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Welcome
The “1st Canterbury Workshop on Optical Coherence Tomography and Adaptive Optics” has been
initiated as a reporting meeting of the Marie Curie training site (MCTS) for early stage training
(EST) researchers, MEST-2005-020353 supported by the European Commission (EC) with
participants from National University of Galway, Ireland, University of Porto, Portugal, Imagine
Eyes, Paris, France, Multiwave Photonics, Porto, Portugal and coordinated by the University of Kent.
The reporting meeting has the generous support of the EC to gather over 20 supervisors and EST
researchers to review the achievements in research of the Marie Curie Training Site.
In opening participation to this meeting to the outside world we aimed not only for a wider scientific
communication exercise, but also to add education to our EST researchers by involving them in an
international exchange of ideas with other specialists in their fields, optical coherence tomography
(OCT) and adaptive optics (AO). At the same time, we hope that other researchers and specialists in
these fields take advantage of the educational component of this meeting.
We are grateful to the sponsors who agreed to offer their generous support to transform the Marie
Curie meeting into a larger size workshop with wide international participation. These industrial
sponsors are innovative companies active in the field of systems and devices for OCT and AO:
Imagine Eyes (France), Michelson Diagnostics (UK), Multiwave Photonics (Portugal), Thorlabs (UK),
Santec (Japan), Superlum (Russia).
We also appreciate the continuing support given by the Ratiu Family Charitable Foundation to the
University of Kent in the form of bursaries enabling Romanian students to further their education in
the field of biomedical imaging and we thank the Foundation for co-sponsoring this workshop.
We welcome you to the University of Kent where research in OCT dates back to 1991, when some of
the precursors of spectral domain OCT, Talbot bands and channelled spectrum low coherence
interferometry for sensing were investigated.
The field of non-invasive high resolution imaging has progressed considerably in the last three years.
Among the participants to our workshop we are fortunate to have leaders in the field, who have been
pushing the limits of acquisition speed. We will all be interested in finding out where those limits stand
today. In the last few years, spectral domain OCT led to a significant increase in the number of
Mega-voxels acquired from the tissue volume, 100 times more than in time domain OCT. Using swept
sources, we expect this limit to exceed 350 Mega-voxels, while good images of the retina at 122
Mega-voxels have been demonstrated so far1. The time to generate an en-face image in spectral domain
OCT has also decreased, but we have not achieved as yet the capability of resonant scanning time
domain OCT. A steady flow of research is manifest in improving the resolution, in depth by OCT and
lateral by AO. In a B-scan generated by spectral OCT, we have recently seen the first demonstration of
AO correction on shrinking the depth profile of the confocal microscope in the retina, however we are
still far from achieving an ultimate resolution of 50 microns in the in vivo retina.
How would the two technologies, OCT and AO look when this limit will finally be achieved? How will
they be best combined? These are stimulating challenges for our continuing research in pushing the
limits of our capabilities. We hope that the “1st Canterbury Workshop in Optical Coherence
Tomography and Adaptive Optics” will contribute towards advancing the frontier of knowledge in
OCT and AO beyond the “natural “ limit which appears to be imposed by current technology.
Adrian Podoleanu
A. Gh. Podoleanu, R. B. Rosen, “Combinations of techniques in imaging the retina with high resolution,“
Progress in Retinal and Eye Research, Vol. 27, No. 4, 464-499 (2008).
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Marie Curie Coordinator
Adrian Podoleanu
School of Physical Sciences, University of Kent
Local organising committee
George Dobre
Michael Hughes
David Jackson
James Redmond
Simon Tuohy
School of Physical Sciences, University of Kent
International organizing committee
Peter E. Andersen, Technical University Denmark
Nicolas Chateau, Imagine Eyes, Paris, France
Tatyana Cherezova, Active Optics Ltd, Moscow, Russia
Chris Dainty, National University of Ireland, Galway, Ireland
Aristide Dogariu, University of Central Florida, Orlando, Florida, USA
Wolfgang Drexler, Cardiff University
Costel Flueraru, National Research Council Canada, Ottawa
Thomas Glynn, National University of Ireland, Galway, Ireland
Fabrice Harms, Imagine Eyes, Paris, France
Joseph Izatt, Duke University, USA
Dean Johnson, Haag-Streit UK
Peter Koch, Thorlabs Luebeck, Germany
Antonio Lobo, Multiwave Photonics, Porto, Portugal
Donald Miller, Indiana University, USA
Carla Rosa, University of Porto, Portugal
Richard Rosen, New York Eye and Ear Infirmary, NY, USA
Jose Salcedo, Multiwave Photonics, Porto, Portugal
David Sampson, University of Western Australia, Crawley, Australia
Jose Luis Santos, University of Porto, Portugal
Ruikang Wang, Oregon Health and Science University, USA
Maciej Wojtkowski, Torun University, Poland
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Conference planner
Monday
8 September
Tuesday
9 September
Wednesday
10 September
9:30 – 10:30 Visit of the
Applied Optics Labs in
the Photonics Centre
9:00 – 10:30
Session 9
Adaptive Optics I
10:30 – 11:00
Santec
refreshments break
10:45 – 11:15
Michelson Diagnostics
refreshments break
10:30 – 11:00
Thorlabs
refreshments break
11:00 – 12:30
Session 2
OCT in the clinic
11:15-12:30
Session 5
Optical sources II
11:00-12:15
Session 10
Imaging the eye I
12:30 – 14:00
Lunch
12:30-14:00
Lunch
12:15-13:45
Lunch
14:00 – 15:30
Session 3
OCT technology
14:00- 15:15
Session 6
Modulation of Optical
Reflectivity
13:45- 15:30
Session 11
Adaptive Optics II
15:30 – 16:00
Superlum
refreshments break
15:15 – 15:45
Multiwave Photonics
refreshments break
15:30 - 16:00
Imagine Eyes
refreshments break
15:45-16:45
Session 7
OCT for art
16:00 – 17:15
Session 12
Imaging the eye II
9:15 – 9:30
Welcome and opening
remarks
9:30 – 10:30
Session 1
OCT Microscopy
16:00 – 17:30
Session 4
Optical sources I
17:30 – 19:00
Poster session 1 with
wine and nibbles
16:45 - 17:45
Session 8
Intellectual Property
Rights
19:00 – 21:30
Gala Dinner
Darwin College
Conference Suite
5
17:15-19:00
Poster session 2 with
farewell drinks
1st Canterbury Workshop on OCT and AO
Daily events planner and conference schedule
Each paper’s proceedings number is indicated in the first column in the
table below. Please use this number in your correspondence.
MONDAY 8th September
Registration, Marlowe building foyer, 8:00-9:15
Paper
Number
1
Time
Speaker
Title
9:15 - 9:30
A. Podoleanu
Welcome and opening remarks
Session 1: OCT Microscopy
Chair: Robert Huber
2,3
4
9:30 - 10:00
10:00-10:15
J. P. Rolland
Y. Verma
5
10:15-10:30
L. Ma
10:30 – 11:00
Gabor Domain Optical Coherence Microscopy
In-Vivo Imaging of Adult Zebrafish Using OCT
Using en-face OCT to analyse gene function in Drosophila
Melanogaster larval heart
Santec Refreshments Break
Session 2: OCT in the clinic Chair: Jannick Rolland
6
11:00-11:30
D. D. Sampson
7
8
9
11:30-11:45
11:45-12:00
12:00-12:15
M. Bonesi
R. A. McLaughlin
A. Z. Freitas
10
12:15-12:30
C. Todea
Anatomical optical coherence tomography of the
upper and lower airway
Doppler OCT in cardiovascular physiology
Can normal lymph node architecture be characterised by OCT?
Structural Characterization of Hair Fiber by OCT
En-face OCT microleakage investigation after laser-assisted dental
hard tissue treatment
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MONDAY 8th September
Afternoon sessions
12:30 – 14:00
Lunch
Session 3: OCT technology
Chair: David Sampson
11
14:00 - 14:15 S. Tamborski
Analysis of extinction and flow velocity with joint Spectral and Time
domain OCT
12
14:15 - 14:30 B. Veksler
Application of OCT for imaging of scaffold structure and micro-flows
characterization
13
14:30 - 14:45 V. F. Duma
Theoretical approach on a galvanometric scanner with an enhanced duty cycle
14
14:45 - 15:00 J. Holmes
Theory & Applications of multi-beam OCT
15
15:00 - 15:15 P D Woolliams
Measurement of the 3D Point-Spread Function in an OCT Imaging
System
16
15:15 - 15:30 M.R.N. Avanakia
Denoising Based on Noise Parameter Estimation in Speckled OCT
Images Using Neural Network
15:30-16:00
Superlum Refreshments break
Session 4: Optical sources I Chair: Antonio B. Lobo Ribeiro
17
16:00-16:45
R. Huber
Wavelength swept laser sources: Technology and applications
for OCT
18
16:45-17:30
H. Crespo and
C. Rosa
Femtosecond lasers in OCT
17:30-19:00
Poster session 1 and drinks reception
The list of posters is at the end of this document
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TUESDAY 9th September
Morning Sessions
No
Time
Speaker
Title
Visits of the Applied Optics Group Labs 3 groups of 10 people at 15 minute intervals. Please book your option early
9:30 - 10:00
Visit of the AOG labs
9:45 - 10:15
Visit of the AOG labs
10:00-10:30
Visit of the AOG labs
10:45 – 11:15
Michelson Diagnostics Refreshments Break
Session 5: Optical sources II
Chair: Thomas Glynn
19
11:15-11:45
A. B. Lobo Ribeiro
Optical Fibre Sources for Measurement and Imaging
20
11:45-12:00
Yu.O.Kostin
Towards 1.0W CW Reliable SLD at 840 nm
21
12:00-12:15
Yu.O.Kostin
Towards 100 nm Wide SLDs at 840 nm Band
22
12:15-12:30
S. Marschall
Frequency-swept laser light source at 1050 nm with higher bandwidth
due to multiple SOAs in series
12:30-14:00
Lunch
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TUESDAY 9th September
Afternoon Sessions
Session 6: Modulation of optical reflectivity
Chair: Yoshiaki Yasuno
23
14:00-14:45
A. R. Tumlinson
Retinal intrinsic optical signal and OCT
25
14:45-15:00
M. Leitner
Differential absorption OCT with nanoparticles as the contrast agent
26
15:00-15:15
S. G. Adie
Optical coherence elastography of tissue at acoustic frequencies
15:15-15:45
Multiwave Photonics Refreshments Break
Session 7: OCT for art
Chair: Michael Pircher
27
15:45-16:15
H. Liang
Optical Coherence Tomography in Art Conservation &
Archaeology – a new emerging field
28
16:15-16:30
E. Kwiatkowska
Optical Coherence Tomography for Non-Destructive Investigations of
Structure of Easel Paintings
29
16:30-16:45
M. Hughes
A Swept-Source OCT at 1300 nm for Art & Archaeological
Conservation
Session 8: General skills
30
16:45 - 17:45 T. Prock
19:00–21:30
Chair: Adrian Podoleanu
Intellectual Property Rights
DINNER
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WEDNESDAY 10th September
Morning sessions
No
Time
Speaker
Title
Session 9: Adaptive Optics I
Chair: Robert Zawadzki
31
9:00 - 9:45
C. Dainty
Adaptive Optics
32
9:45 - 10:00
D. T. Miller
Does transverse chromatic aberration limit performance of AO-OCT retinal
imaging?
33
10:00 -10:15 S. Tuohy
Imagine Eye Adaptive Optics Loop for en-face OCT
34
10:15-10:30
Performance Assessment of a Pupil Tracking System for Adaptive Optics
Retinal Imaging
B. Sahin
10:30-11:00
Thorlabs Refreshments Break
Session 10: Imaging the eye I
35
11:00-11:30
M. Pircher
36
11:30-11:45
B. Považay
37
11:45-12:15
C. Torti
Chair: Christopher Dainty
Simultaneous SLO/OCT Imaging of the Human Retina in vivo with
High Speed Axial Eye Motion Correction
High-Speed High-Resolution Optical Coherence Tomography at 800 and
1060 nm
Revealing fine microstructural morphology in the living human
retina using optical coherence tomography with pancorrection
12:15-13:45
Lunch
10
WEDNESDAY 10th September
Afternoon sessions
Session 11: Adaptive Optics II
Chair: Donald T. Miller
38
13:45-14:30
F. Harms
Applications of Adaptive Optics in ophthalmology
39
14:30-14:45
E. Odlund
Optimization of the Temporal Performance of a Deformable Mirror for Use in
Ophthalmic Applications
40
14:45-15:00
M. Blavier
First steps toward 3D high resolution imaging using adaptive optics and
full-OCT
41
15:00-15:30
R. Zawadzki
Challenges and possibilities for developing AO - ultra-high
resolution OCT for clinical in vivo retinal imaging
15:30-16:00
Imagine Eyes Refreshments Break
Session 12: Imaging the eye II
Chair: Wolfgang Drexler
42
16:00-16:45
Y. Yasuno
Optical Coherence Tomography for the Investigation of Posterior
and Anterior Eye Segments
43
16:45-17:00
K.M.
Karnowski
Anterior Segment Imaging Using High Speed Swept Source OCT
44
17:00-17:15
S. Makita
Full-range, high-speed, high-resolution 1 μm spectral-domain optical
coherence tomography with BM-scan method for the human posterior eye
imaging
17:15-19:00
Poster Session 2 and Farewell drinks
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Posters
Please display the posters as soon as you arrive. All posters will be subject to discussion starting from the first refreshments break on
Monday and continuing with Poster session 1 on Monday at 17:30. Posters should be displayed for the whole duration of the workshop.
Poster session 2 is scheduled on Wednesday at 17:15. Please collect your poster after 19:00 on Wednesday evening. Poster authors should
be present at both poster sessions.
Number Poster
Presenter
of paper Number
45
1
S. Chiesa
Title
46
47
48
49
2
3
4
5
M. Nowakowski
A. Meadway
S. Gigan
M. L. Negrutiu
50
6
R. O. Romînu
51
7
C. Sinescu
52
53
8
9
S. Gruensteidl
S. Manjooran
54
55
56
10
11
12
J. Wang
L. Neagu
I. Trifanov
57
58
13
M. Volynsky
An Adaptive Optics Assisted Retinal Imaging System using a Pyramid Wavefront
Sensor
Measurements of the optical aberrations within a 10deg field in the eye
Multi-Channel Time Domain Spectroscopic Optical Coherence Tomography System
Towards a compact coherence-gated wavefront sensor for microscopy
Optical coherence tomography and confocal microscopy investigations of dental
prostheses
An Innovative Approach for Investigating the Ceramic Bracket-Enamel Interface –
OCT and Confocal Microscopy
Combining Optical Coherence Tomography and Confocal Microscopy Investigation of
the defects inside the Ceramic Fixed Partial Dentures
Improvement of the mode quality in Large Mode Area (LMA) fibres
Development and characterisation of laser ablative process for synthesis of
nanoparticles
Multiple Delay Lines Full-field Optical Coherence Tomography
En-face OCT system at 1060 nm
Development and Optimization of Fibre Optic Broadband Sources at 1 micron region
for OCT
High-resolving full-field OCT system for investigation of random tissues
14
N Krstajic
In-vitro and in-vivo OCT image contrast
59
15
I. Trifanov
24
60
16
17
C. Maule
B. R. Penmetsa
Quasi – sequential operation of en-face OCT and CM(SLO) synchronous with the
transversal scanner
Nanoparticles for Enhanced Contrast OCT
Imaging of basal cell carcinoma tissue using en-face OCT
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MONDAY 8th September
SESSION 1
OCT Microscopy
Chair: Robert Huber
9:30 - 10:00 Invited: Gabor Domain Optical Coherence
Microscopy
Jannick P. Rolland*, Panomsak Meemon, Supraja Murali, and Kye-sung Lee
CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, FL
32816
*Corresponding author: [email protected]
Optical Coherence Microscopy (OCM) is an emerging technology capable of depth
sectioning of biological tissue at the micrometer scale. In this paper, we propose a
developing technology called Gabor Domain Optical Coherence Microscopy (GD-OCM),
whose innovation is two folds: (1) A high lateral resolution optical design of a
dynamic-focusing optical probe with no moving parts, which provides an invariant
resolution of currently 3 m and up to 2 mm full-field of view and 2 mm imaging depth by
design; (2) An acquisition scheme (using the probe) that is capable of performing automatic
data fusion to render an in-focus high resolution image throughout the depth of sample at
in vivo speeds.
10:00:10:15 In-Vivo Imaging of Adult Zebrafish Using Optical Coherence
Tomography
Y. Verma , K. Divakar Rao, and P. K. Gupta
Laser Biomedical Applications and Instrumentation Division
Raja Ramanna Centre for Advanced Technology
Indore, India-452013, [email protected]
Zebrafish (Danio rerio) a vertebrate is a good model system in medical research to understand
a variety of human biological processes. These studies often require measurements of the
morphological and physiological parameters of Zebrafish. Therefore, development of
noninvasive imaging techniques for this purpose is of considerable interest. In this article, we
present a brief overview of use of OCT for noninvasive in-vivo imaging of adult Zebrafish.
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10:15- 10:30 Using en-face optical coherence tomography to analyse gene
function in Drosophila Melanogaster larval heart
Adrian Bradu1, Lisha Ma2, Jim Bloor2 and Adrian Podoleanu1
Applied Optics Group, School of Physical Sciences, University of Kent, CT2 7NH, Canterbury, United
Kingdom
2 Cell Biology & Developmental Group, Department of Biosciences, University of Kent, CT2
7NJ,
Canterbury, United Kingdom
In-vivo Optical Coherence Tomography (OCT) imaging of the fruit fly Drosophila
Melanogaster larval heart allows non invasive visualizations and assessment of its cardiac
function. In order to image Drosophila heart, we have developed a dedicated imaging
instrument able to provide simultaneous OCT and Laser Scanning Confocal Microscopy
(LSCM) images. With this dual imaging system, the heart can easily be located and
visualised within the specimen and the change of the heart shape in a cardiac cycle
monitored. Here we have used targeted gene expression to knockdown the myospheroid
(mys) gene in the larval heart using a specific RNAi construct. By knocking down a β
integrin subunit encoded by mys we have recorded an enlarged heart chamber in both
diastolic and systolic states. Also, the fraction of reduction of the chamber diameter was
smaller in the knockdown heart. These phenotypic differences indicate that impaired
cardiac contractility occurs in the heart where the integrin gene express level is reduced.
At our knowledge, this is for the first time when it is shown that integrins have a direct
relationship to a dilated heart defect.
1
10:30 – 11:00 Santec Refreshments break
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SESSION 2
OCT in the clinic
Chair: Jannick Rolland
11:00 - 11:30 Invited: Anatomical optical coherence
tomography of the upper and lower airway
D. D. Sampson
Optical & Biomedical Engineering Laboratory, University of Western Australia, Crawley
WA 6009, Australia
Anatomical optical coherence tomography (aOCT) is an endoscopic optical technique that
enables continuous, quantitative assessment of hollow organ size and shape in three
dimensions - at the bedside and in the operating theatre. It is a powerful alternative to
X-ray computed tomography, magnetic resonance imaging, and other indirect methods
for the assessment of hollow-organ anatomy. We will describe examples of clinical
research underway with aOCT in the upper and lower airway. In the upper airway, this
includes studies in sleep apnoea, such as evaluation of changes in pharyngeal shape and
size in individuals with and without obstructive sleep apnoea, including the effect of body
posture. In the lower airway, we demonstrate the capacity of aOCT to usefully determine
stent size in the theatre during treatment of lower airway obstruction in a range of
patients, as well as the ability to perform regional compliance measurements. The
capacity of aOCT to monitor dynamic breathing-related changes in airway shape and size
will be demonstrated. Technical issues, including the incidence of incomplete data due to
shadowing or low signal-to-noise ratio, the necessary measurement range,
and limitations caused by motion artefact and means of addressing it, will be
described. Finally examples of three-dimensional anatomical reconstruction will be
given.
11:30 – 11:45 Doppler OCT in cardiovascular physiology
M Bonesi, IV Meglinski and SJ Matcher
Biomedical Engineering, The Kroto Institute, University of Sheffield, Broad Lane, Sheffield
S3 7HQ
Doppler optical coherence tomography (DOCT) is a functional extension of OCT and has
the capability to simultaneously perform cross-sectional imaging of sample structure and
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fluid flow velocity distribution in turbid media. It offers high spatial resolution (1-15 um)
and good velocity resolution, down to 10 um s-1. Several groups have reported the
capability of DOCT technique to image flow velocity profiles in phantoms and blood vessels
in vivo. The study of the mutual effect and interactions of the blood flow with the
surrounding vessel geometry is of great interest in biorheology and cardiology. In
particular, DOCT technique could become a valid support for cardiologists as a means of
simultaneous imaging of the vessel morphology and related blood flow velocity
distribution. A range of useful information can be derived from the acquired velocity
profiles including turbulence monitoring in complex geometry vessels (e.g. at vessels
junction or vessels with aneurysm), the effect of stenting on blood flow dynamic, and
computation of shear stress acting on vessel walls. Using the DOCT system, we performed
a set of experiments to get better insight into flow dynamics and formation at the junction
site of vessels with deployed stent. The artificial vessels were custom built and designed to
mimic the complex geometry of human blood vessels of ~1 mm in diameter. Flow dynamics
was monitored through the Y-shaped junction with deployed stent. Measurements were
performed with constant input volume flow rate. We observed: 1) laminar cross-sectional
flow dynamic distribution, 2) disruption of laminar regime at the junction site and past the
stent, and 3) restoration of laminar regime where the vessel geometry returned to regular
shape. The performed measurements include also the monitoring of the flow dynamics in
sub-millimeter vessels using an oscillatory pump.
11:45 – 12:00 Can normal lymph node architecture be characterised by optical
coherence tomography?
R.A.McLaughlina, L.Scolaroa, B.R.Klyena, S.Hamzab, P.Robbinsc, C.Saundersb,d,
D.D.Sampsona
aOptical+Biomedical Engineering Laboratory, University of Western Australia, Crawley
WA 6009, Australia
bSir Charles Gairdner Hospital, Crawley WA 6009, Australia
cPathWest QEII Medical Centre, Crawley WA 6009, Australia
dSchool of Surgery, Uni. Western Australia, Crawley WA 6009, Australia
Assessment of lymph node involvement is a key prognostic marker in early breast cancer.
This paper demonstrates the ability of optical coherence tomography (OCT) to characterise
the micro-architecture of healthy, non-cancerous lymph nodes. OCT is shown to
differentiate stroma, cortex and adipose tissue. Characteristic patterns are also identified
for germinal centres and blood vessels within the node. Results are correlated against a
histopathological gold standard.
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12:00 – 12:15 Structural Characterization of Hair Fiber by Optical Coherence
Tomography
Freitas, A.Z.1; Velasco, M.V.R.2; Raele, M.P.1; Kaneko, T.M.2; Vieira Jr., N.D.1;
Baby, AR.2
1 Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e
Nucleares (IPEN-CNEN/SP), Brasil
2 Departamento de Farmácia, Faculdade de Ciências Farmacêuticas,
Universidade de São Paulo (FCF-USP), Brasil
In this work we use the OCT technique to produce in vitro transversal section images of
human hair. It was possible to identify in the A-scan protocol its principal structures:
cuticle, cortex and medulla. The mean diameter of medulla was 29 ± 7 μm and hair
diameter was 122 ± 16 μm in our samples of standard Afro-ethnic hair. We also compared
the OCT signal before and after chemical treatment with 18% w/w ammonium
thioglycolate solution. After chemical treatment, it was not possible to identify the main
structures of hair fiber, due the index matching promoted by deleterious action of chemical
agent. A tridimensional image was built starting from 601 cross-sectional images (slices).
Each slice was taken in steps of 6.0 μm at 8 frames per second, and the whole 3D image
was built in 60 seconds.
12:15–12:30 En-face OCT microleakage investigation after laser-assisted dental
hard tissue treatment
Carmen Todea1, Cosmin Balabuc1, Cosmin Sinescu1, Meda Negrutiu1, Laura Filip1,
Michael Hughes2, Adrian Bradu2, Adrian Podoleanu2
1School of Dentistry, University of Medicine and Pharmacy of Timisoara, Bvd. Revolutiei
1989 No. 9, 300070, Timisoara, Romania
2University of Kent, School of Physical Sciences, Applied Optics Group, Canterbury, CT2
7NH United Kingdom
Purpose: To investigate using en-face Optical Coherence Tomography (OCT) the
microleakage after Er:YAG laser cavity preparation.
Material and Methods: Thirty single- and multi-rooted freshly extracted human teeth
divided into two study groups, group I (laser) and group II (control), were used in this
study. In group I, Class V cavities were prepared using laser on the buccal surface of each
tooth. The laser device used was an Er:YAG laser (2940 nm, VSP, 250-320 mJ, 10-20 Hz).
In group II, cavities were prepared conventionally and acid etched on the oral surface of
the same tooth. All cavities were filled with composite resin. The cavity microleakage was
17
investigated using en-face Optical Coherence Tomography prototype, based on transverse
scanning and operating at 1300 nm.
Results: The investigation demonstrated qualitatively the reduction of microleakage in
cavities prepared with Er:YAG laser as compared to the control group, in which cavities
were prepared conventionally.
Conclusion: The en-face OCT method provided a superior non-invasive and real time
investigation method, thus reducing the occurrence of secondary caries by early detection.
Moreover, based on the results of this investigation, it may be concluded that Er:YAG
laser-assisted cavity preparation leads to reduction of microleakage.
12:30 – 14:00
Lunch
SESSION 3
OCT technology
Chair: David Sampson
14:00 – 14:15 Analysis of extinction and flow velocity with joint Spectral and
Time domain OCT
Szymon Tamborski, Maciej Szkulmowski, Anna Szkulmowska, Andrzej Kowalczyk,
Maciej Wojtkowski
Institute of Physics, Nicolaus Copernicus University, ul. Grudziądzka 5, PL–87-100 Toruń,
Poland [email protected]
Optical Coherence Tomography in both Spectral and Time domain variants has become an
exceptionally useful tool for retrieval of structural information of diverse media of
sufficient scattering properties. Advantages of its applications are taken especially in
circumstances where non-invasive in situ and in vivo imaging techniques are desired.
Moreover, the great potential which lies in coding information in properties of laser light
scattered back from the inside of the object under investigation gives a possibility of
gaining much more information than just structural. In this contribution the recipe is
presented how to make use of it to get both depth dependent extinction and velocity of
flows. In the presented method, which takes advantages of both Spectral and Time domain
OCT variants, spectral fringe patterns of sufficient number are acquired in time
18
increments for the fixed point of the sample. This enables estimation of an axial component
of a flow velocity vector from Doppler beating signal. On the other hand, FT−1 of measured
signal followed by windowed FT returns light spectrum as a function of an axial
coordinate. From such data spatial distribution of extinction coefficient may be determined
providing additional characteristics of the medium. In this contribution the details of the
theory of this spectroscopic OCT analysis as well as flow velocity measurement technique
are followed by the demonstration and comments on experimental results.
14:15 – 14:30 Application of optical coherence tomography for imaging of scaffold
structure and micro-flows characterization
B. Veksler, E. Kobzev, M. Bonesi, and I. Meglinski
Cranfield Health, Cranfield University, Silsoe, MK45 4DT, UK
Three-dimensional porous scaffolds possess a great opportunity for the directional growth
of the cells in tissue engineering and for the supplying them with nutrients. However, the
complex porous structure of the scaffolds creates difficulties for the measurements and
control of nutrients flow. We applied optical coherence tomography (OCT) for imaging of
the scaffold structure. We also investigated the possibility of using Doppler OCT to
monitor the flow velocity distribution within the scaffold. The average scaffold’s pore
diameter has been estimated using electron microscopy. We shown that with Doppler OCT
it is possible to monitor complex micro-flow and estimate the shear stress (i.e. enhancing
factor of cell growing) acting on the cells within the scaffold and to find the optimal input
flow rate, consequently.
14:30 – 14:45 Theoretical approach on a galvanometric scanner with an
enhanced duty cycle
V.-F. Duma*a, A. Gh. Podoleanub
aDept. of Product Design, Aurel Vlaicu University of Arad, 77 Revolutiei Ave., 310130
Arad, Romania;
bSchool of Physical Sciences, University of Kent at Canterbury, Canterbury, CT2 7NH,
U.K.
The paper explores the possibilities of achieving a galvanometric scanner with an
enhanced, as close as possible to 100%, duty cycle (η) even for high scan, i.e. high
oscillation, frequencies. Nowadays solutions provide high η, but up to certain frequencies.
The study of this limit frequency, of its relationship with the duty cycle, and the
ascertainment of the scanning and command functions that may produce better results, is
the final scope of this work. The scanning device is considered in a setup characteristic to
the dimensional, usually on-line, industrial measurements. A detailed theoretical study is
performed, starting with the equation of the mobile element of the galvoscanner. The
19
expressions of the active torque and of the necessary command function that has to be used
are obtained, with regard to the desired scanning function. This is considered linear and
symmetrical on its active portions and with non-linear returning portions that have to be
performed as fast as possible. Two such functions for the returning portions are considered
and studied: parabolic and sinusoidal. The best scanning function, with regard to
achieving the objectives of the device (high duty cycle for high frequencies), is discussed
and the way the necessary command function has to be deduced is discussed.
14:45 - 15:00 Theory & Applications of multi-beam OCT
Jon Holmes, Chief Executive, Michelson Diagnostics Ltd
Orpington, Kent, UK
The lateral resolution of Fourier domain optical coherence tomography (FD-OCT) systems
is limited by the depth of focus that can be achieved over the desired imaging depth at the
chosen wavelength. We present a solution in which multiple beams focused at different
depths are scanned together, so that a mosaic image can be produced, with at least double
the resolution possible from a single beam system. Side-benefits also arise from the ability
to combine data from each beam to improve signal-to-noise. The theory of this approach is
discussed, advantages, and also the practical realisation in a variety of ex-vivo and in-vivo
OCT imaging probes, together with results from a number of applications.
15:00 - 15:15 Measurement of the Three-Dimensional Point-Spread Function in
an Optical Coherence Tomography Imaging System
P D Woolliams1*, P H Tomlins1, M Tedaldi1, C J Hart1, A Grimwood2
1)Optical Technologies Group, National Physical Laboratory, Hampton Road,
Teddington, Middlesex, TW11 0LW, UK
2)London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH
*Contact [email protected]. +44(0)20 8943 6328
As Optical Coherence Tomography (OCT) is now becoming established as an important
clinical tool for both diagnostics and fundamental biological research a simple way of
characterising the resolution performance of OCT instruments would aid in the
quantitative analysis of the data. We are developing a reference phantom and
measurement methodology to enable this. Conventionally the axial resolution is generally
defined in terms of the coherence length of a Gaussian shaped source, the transverse
system resolution being defined using the Rayleigh Criterion or from Gaussian beam
optics. Whilst these definitions provide a useful mathematical reference they are
somewhat abstracted from the three dimensional resolution that is encountered under
practical imaging conditions. Therefore, we have developed a three-dimensional resolution
target and measurement methodology that can be used to calibrate the three-dimensional
resolution of OCT systems.
20
15:15 – 15:30 Denoising based on noise parameter estimation in speckled OCT
images using neural network
Mohammad R. N. Avanakia, P. Philippe Laissuea, Adrian G. Podoleanub and Ali Hojjata
a Kent Institute of Medicine and Health Sciences,
University of Kent, Canterbury, CT2 7PD, UK
b Applied Optics Group, School of Physical Sciences,
University of Kent, Canterbury, CT2 7NH, UK
This paper presents a neural network based technique to denoise speckled images in
optical coherence tomography (OCT). Speckle noise is modeled as Rayleigh distribution,
and the neural network estimates the noise parameter, sigma. Twenty features from each
image are used as inputs for training the neural network, and the sigma value is the single
output of the network. The certainty of the trained network was more than 91 percent and
the Signal-to-Noise ratio of the denoised image is considerably increased. Image
assessment was done with three No-Reference metrics and the results were promising.
15:30-16:00
Superlum Refreshments break
SESSION 4
Optical Sources I
Chair: Antonio B. Lobo Ribeiro
16:00 – 16: 45 Invited: “Wavelength swept laser sources:
Technology and applications for optical coherence
tomography”
Robert Huber, LMU Munich at the Chair for BioMolecular Optics
Wavelength swept laser sources are the key component in swept source optical coherence
tomography (ss-OCT) or for optical frequency domain imaging (OFDI). Whereas tunable
lasers have been applied for other applications for a long time, the required performance
specifications for OCT differ from typical tunable lasers. Compared to standard tunable
lasers, swept lasers for OCT require less coherence length, but orders of magnitude faster
sweep rates and tuning ranges. Different approaches to achieve this goal will be reviewed
21
and the advantages and disadvantages of ss-OCT/OFDI compared to other
OCT-techniques will be discussed. The physics and laser dynamics of these sources will be
explained and a technical overview over the integration of these sources into high
performance OCT systems will be given. The analysis of strengths and weaknesses of
ss-OCT systems serves for a prognosis of the future of such systems in OCT.
16:45-17:30 Invited: "Femtosecond lasers in OCT"
Helder Crespo and Carla Rosa,
University of Porto, Portugal
"Femtosecond mode-locked Ti:sapphire laser oscillators are an optical source of choice for
ultrahigh-resolution optical coherence tomography. Dispersive mirror technology has
enabled the generation of smooth near-octave-spanning spectra centered at 800 nm
directly from these lasers, which provide sub-micrometer axial and lateral resolutions
with high signal-to-noise ratios. Nonlinear optical devices, in particular photonic crystal
fibers (PCFs) can be used to further extend the spectral range of the laser output, both in
terms of bandwidth and available wavelengths. We will focus on the technology and
particular characteristics of femtosecond laser systems, as well as on practical aspects on
the use of these optical sources in optical coherence tomography, such as spectral shaping
techniques, optical configurations and their performance."
17:30-19:00
Poster session and drinks reception
The list of posters is at the end of this document
22
TUESDAY 9th September
9:30 to 10:30 Group visit of AOG labs at 15 minute intervals
Please book your option on registration
10:45-11:15
Michelson Diagnostics Refreshments break
SESSION 5
OPTICAL SOURCES II
Chair: Thomas Glynn
11:15 – 11:45 Invited: Optical Fibre Sources for Measurement
and Imaging
Antonio B. Lobo Ribeiro, Multiwave Photonics, Porto, Portugal
http://www.multiwavephotonics.com
This course describes the basic principles of fibre optic sources based in rare earth-doped
glass fibres, which are used in metrology and optical imaging. It also provides a broad
overview of the different types of fibre broadband sources (or superfluorescent fibre
sources - SFS) and some fibre laser sources that operate as broadband sources for imaging
applications. The performance and characteristics of several fibre sources are reviewed,
including configurations, emission spectra profiles, autocorrelation functions, noise,
wavelength and power stability, and polarization behaviour.
11:45 – 12:00 Towards 100 nm Wide SLDs at 840 nm Band
Yu.O.Kostin, P.I.Lapin, V.R.Shidlovsky, and S.D.Yakubovich
SUPERLUM DIODES Ltd. P.O.Box-70, Moscow 119454 Russia
E-mail: [email protected]
The results of development of superluminescent diodes (SLDs) based on a new
quantum-well (QW) (GaAl)As and (InGa)As heterostructures in 800 – 900 nm spectral
range with spectral bandwidths of 70-80 nm are presented.
23
12:00 – 12:15
Towards 1.0W CW Reliable SLD at 840nm
Yu.O.Kostin, P.I.Lapin, V.V.Prokhorov, V.R.Shidlovsky, and S.D.Yakubovich
SUPERLUM DIODES Ltd. P.O.Box-70, Moscow 119454 Russia
E-mail: [email protected]
The prototypes of high-efficiency SLDs with COD threshold of more than
5106W/cm2 were investigated. Single spatial mode samples with 4m-wide
active channel exhibited CW output power of more than 200mW. Preliminary
reliability tests at 100mW level were successful. It was shown that in
double-pass operation mode achieved using SM fiber reflector, external
efficiency can be increased significantly. The estimations show that
multimode SLD with 20-30m active channel width based on the same QW
heterostructure may ensure reliable enough operation at output power level
of more than 0.5W.
12:15 – 12:30
Frequency-swept laser light source at 1050 nm with higher
bandwidth due to multiple SOAs in series
Sebastian Marschall1, Lars Thrane1, Christian Pedersen1, Kevin Hsu2, and Peter E. Andersen1
1 Dept. Photonics Engineering, Technical University of Denmark, Roskilde, Denmark
2 Micron Optics, Atlanta, US
Semiconductor Optical Amplifiers (SOA) in a fibre ring cavity in combination with rapidly
tuneable narrowband filters are one possible way to implement frequency-swept laser light
sources that can be used for OCT. The effective spectral bandwidth of the output is limited by
the width of the gain spectrum of the SOA. To further increase the bandwidth one can put
several SOA's with different centre wavelengths in parallel. However, provided the gain
spectra are sufficiently similar two SOA's in series can also enhance the spectral width of the
output.
In this work, we demonstrate that two SOA's in series with nearly equal gain spectra can
improve the performance of the light source. This is explained by the higher small signal gain
allowing saturation of the amplifiers even at higher tuning speeds of the filter. We compare the
so-called Serial SOA configuration (SSOA) with the common Master Oscillator/Power
Amplifier architecture (MOPA), where one has a single SOA in the ring resonator and a second
one outside to boost the output power. We show that for high sweep rates the SSOA
configuration could maintain significantly higher bandwidths—or alternatively higher output
power at the same bandwidth—compare to the MOPA architecture.
12:30-14:00
Lunch
24
SESSION 6
Modulation of optical reflectivity
Chair: Yoshiaki Yasuno
14:00 – 14:45 Invited: Retinal intrinsic optical signal and
optical coherence tomography
A. R. Tumlinson1, B. Hermann1, B. Hofer1, B. Povazay2, C. Torti1, W. Drexler1
1Biomedical
Imaging Group, School of Optometry & Vision Sciences, Cardiff University,
Wales, UK
2 Department of Physiology, Medical University of Vienna, Austria
The amount of light backscattered from neural tissues changes as a function of activation
and is the basis of intrinsic optical signal (IOS). Typically IOS is observed by looking at
darkfield scatter with a CCD camera. The retina is a calculating portion of the central
nervous grey matter with an optical quality window, and is likewise easily stimulated
optically. Therefore the retina makes a natural model for observing neural interactions
with optical tools. Optical coherence tomography (OCT) is an imaging modality that
provides depth resolved maps of the amount of light backscattered from tissue that has
wide clinical use for observing structural defects associated with ophthalmic disease. It is
therefore also natural to use OCT as means to observe intrinsic optical signal in the retina.
Indeed, OCT has recently been used to observe in an excised rabbit retina an increase in
backscatter at the level of the outer photoreceptor segment after bleaching light
stimulation. We are currently attempting to translate this result towards a diagnostic
technique for photoreceptor dysfunction in human patients. Currently patient motion and
physiological noise present barriers that must be overcome with increases in technological
and experimental sophistication. The talk will review current understanding of retinal
intrinsic optical signal and discuss its measurement challenge.
25
14:45-15:00 Differential absorption optical coherence tomography with
nanoparticles as the contrast agent
*a,b,c
Michael Leitner
, César Maulea,b, Carla C. Rosaa,b, Adrian Podoleanuc
a Optoelectronics Group, Faculty of Science, University of Porto, Rua do Campo Alegre,
687, 4169-007
Porto, Portugal
b INESC Porto, Instituto de Engenharia de Sistemas e Computadores-Porto, Rua do
Campo Alegre, 687,
4169-007 Porto, Portugal
c Applied Optics Group, School of Physical Sciences, University of Kent at Canterbury,
Canterbury,
CT2 7NH, UK
A new variety of nanoparticles show characteristic optical properties that make them
appealing for contrast agents in medical imaging. Metal nanoshells, quantum dots and
rare-earth doped glass nanoparticles are new forms of promising contrast agents which
can be tuned to specific absorption or scattering characteristics within the near-infrared
(NIR) spectrum ranging from 650 – 1300 nm. They have the ability to be used for both
image enhancement and as photosensitive markers due to their well designable scattering
and absorption properties. Furthermore, their strong optical absorption permits treatment
of malignant cells by photoablation processes, induced by heating the nanoparticles with a
matched light source. Differential absorption optical coherence tomography (DA-OCT)
allows for the detection and depth resolved concentration measurement of such markers.
DA-OCT systems normally work with A-scan based images to assess depth resolved
information about the absorption properties and the concentration of a chemical
compound. En-face OCT (B(T) or C scan based images) allows for better depth localization
and a depth resolved concentration measurement of the compound under investigation.
For this aim a multiscan time-domain OCT setup, compatible with different light sources
with different wavelengths and bandwidths in the NIR, is used to study the differential
absorption technique, using different nanoparticles as the contrast agent.
15:00 – 15:15 A first demonstration of audio-frequency optical coherence
elastography of tissue
Steven G. Adie, Sergey A. Alexandrov, Julian J. Armstrong, Brendan F. Kennedy and
David D. Sampson
Optical & Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer
Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western
Australia 6009, Australia
Optical elastography is aimed at using the visco-elastic properties of soft tissue as a
contrast mechanism, and could be particularly suitable for high-resolution differentiation
of tumour from surrounding normal tissue. We present a new approach to measure the
26
effect of an applied stimulus in the kilohertz frequency range that is based on optical
coherence tomography. We describe the approach and present the first in vivo optical
coherence elastography measurements in human skin at audio excitation frequencies.
15:15-15:45
Multiwave Photonics Refreshments Break
SESSION 7
OCT for Art
Chair: Michael Pircher
15:45 – 16:15 Invited: Optical Coherence Tomography in Art
Conservation & Archaeology – a new emerging field
Haida Liang, Nottingham Trent University,
There has been a long tradition of applying biomedical imaging techniques to the
examination of historical artefacts, owing to similar demands for non-invasiveness in both
fields. Optical Coherence Tomography (OCT) is no exception. We review the achievements
on OCT applications to art conservation and archaeology since the publication of the first
papers in 2004. Historical artefacts include a much broader range of materials than
biological tissues, hence presenting a greater and somewhat different challenge to the field
of OCT. New results from a Leverhulme Trust funded project on OCT for art conservation
will be presented to illustrate the various applications of OCT including both qualitative
and quantitative analysis.
16:15 – 16:30 Optical Coherence Tomography for Non-Destructive Investigations
of Structure of Easel Paintings
Ewa Kwiatkowska1, Bogumiła J. Rouba2, Ludmiła Tymińska-Widmer2, Magdalena
Iwanicka2, and Piotr Targowski1
1Institute of Physics, Nicolaus Copernicus University, ul. Grudziądzka 5, 87-100 Toruń,
Poland, e-mail: [email protected]
2Institute for the Study, Restoration and Conservation of Cultural Heritage, Nicolaus
Copernicus University, ul. Gagarina 9, 87-100 Toruń, Poland
In this contribution the application of Optical Coherence Tomography (OCT) for
non-invasive structural imaging of easel paintings will be presented. Since the technique
permits imaging semi-transparent layers accessible for infrared light, the varnish and
27
glaze layers are usually under investigation. The major emphasis will be laid on
application of OCT to resolving specific conservation problems, arising during the
restoration process. The examples of imaging multi-layer varnishes and subsequent
alterations will be given and the application of these images for authentication of
inscriptions will be discussed. Since the thickness of imaged layers may be directly
measured with OCT in completely non-destructive, quick and convenient way as many
times as necessary, the application of the technique to generation of varnish thickness
maps will be presented.
16:30-16:45 A Swept-Source OCT at 1300 nm for Art & Archaeological Conservation
M. Hughes*, D. Jackson, A. Podoleanu
Applied Optics Group, School of Physical Sciences, University of Kent, Canterbury
H. Liang, B. Peric
School of Biomedical & Natural Sciences, Nottingham Trent University,
Nottingham NG11 8NS
D. Saunders
Department of Conservation, Documentation and Science, The British Museum, Great
Russell Street, London WC1B 3DG
M. Spring
Scientific Department, National Gallery, Trafalgar Square, London WC2N 5DN
* [email protected]
We have assembled a swept source OCT at 1300nm for use in Art Conservation and
Archaeology. This system includes dedicated optics to allow for angular averaging for
speckle noise reduction. We describe the operation of the system and present some early
results.
28
SESSION 8
General skills
Chair: Adrian Podoleanu
16:45 - 17:45 Invited: Intellectual Properties Rights
Thomas Prock PhD, Dipl. Ing (Medical Physics and Engineering, Germany)
European Patent Attorney and UK Chartered Patent Attorney
Marks & Clerk, 90 Long Acre, London, WC2E 9RA
[email protected]
http://www.marks-clerk.com/attorneys/profiles_one.aspx?pid=257
The presentation will start with a very basic summary of the requirements for obtaining patent
protection. It would then explain time frames involved in the patent process, the interaction between
patent applications in different countries and the structure of a patent application. This explanation
will be coupled with an exercise attempting to show the contrast between the preferred embodiments of
an invention and the actual inventive concept (which will often be much broader than any specific
embodiment). The talk will finish with considerations specific to the medical technologies field.
19:00–20:30
Gala Dinner
Darwin College Conference Suite
29
WEDNESDAY 10th September
SESSION 9
Adaptive Optics I
Chair: Robert Zawadzki
9:00 - 9:45 Invited: Adaptive Optics
Christopher Dainty, National University of Ireland, Galway, Ireland
Summary

Overview of adaptive optics, Describing aberrations: Zernike polynomials,
Wavefront sensors, Wavefront correctors, Control systems for AO Applications of
AO in vision science, Other applications of AO
9:45 – 10:00 Does transverse chromatic aberration limit performance of AO-OCT
retinal imaging?
Donald T. Miller, Barry Cense, Eric Koperda, Ravi S. Jonnal, and Weihua Gao
Indiana University, School of Optometry, Bloomington IN 47405
The combination of adaptive optics (AO) and optical coherence tomography (OCT) has been
successfully applied to in vivo retinal imaging, motivated by the potential of
unprecedented 3D resolution. The eye, however, not only suffers from monochromatic
aberrations, which are corrected by AO, but also substantial chromatic aberrations, which
are not. To correct chromatic aberrations, achromatizing lenses have been recently
employed in ultrahigh resolution AO-OCT instruments. These lenses, like their earlier
predecessors for vision improvement, effectively correct the eye’s longitudinal chromatic
aberration (LCA), but make no attempt at the complementary transverse chromatic
aberration (TCA). This raises an important concern as to the degrading impact of TCA on
the 3D resolution of AO-OCT and OCT retina cameras. To address this, we undertook a
theoretical analysis of TCA for high-resolution retinal imaging in conjunction with
laboratory measurements. The theoretical analysis included the two primary contributors
of TCA for retinal imaging: (1) errors in the lateral positioning of the eye and (2) off-axis
imaging. The analysis predicted the extent to which TCA impacts retinal imaging and the
conditions under which it can be held at acceptable levels for AO-OCT and OCT. Several
near-infrared bands were chosen that correspond to common OCT light sources. To
substantiate the theoretical predictions, laboratory measurements were obtained with the
Indiana AO-OCT instrument and from which TCA properties were derived.
30
10:00 – 10:15 Imagine Eye Adaptive Optics Loop for en-face OCT / microscopy
Simon Tuohya, Adrian Gh. Podoleanua, Fabrice Harmsb, Nicolas Chateaub
aPhotonics
Centre, School of Physical Sciences, University of Kent, CT2 7NH Canterbury,
UK
bImagine Eyes, 91400 Orsay, France
The capabilities of a novel deformable mirror and wavefront sensor combination to correct
aberrations in microscopy are analyzed. The deformable mirror, (Mirao52-D, Imagine
Eyes) is incorporated with a Shack-Hartmann sensor (HASO, Imagine Optic) within a
complex imaging system able to produce simultaneous en-face Optical Coherence
Tomography (OCT) and Confocal microscopy images. A large angle imaging along one of
the scanning directions is demonstrated using the AO loop to correct for the interface
optics aberration. The image is split into three panels, and each panel is imaged using its
own set of corrections. The three images are subsequently collaged into a final image.
10:15 – 10:30
Performance Assessment of a Pupil Tracking System for AO
Retinal Imaging
1, 2
2
2
Betul Sahin , Fabrice Harms , Barbara Lamory
Applied Optics Group, Physics Department, National University of Ireland Galway
(NUIG)
1
Imagine Eyes, Orsay, France
2
Adaptive Optics (AO) is particularly suitable for correction of aberrations that change over
time – a necessity for high resolution imaging of the retina. However, AO imaging
performance is affected by eye and head motion so wavefront sensors with high repetition
rates are often required. We developed a new approach for enhancing aberration correction
in AO retinal imaging by integrating a Pupil Tracking System (PTS) into the AO loop. In
this study we assessed the performance of the PTS developed for this purpose. Tests have
demonstrated that the device achieves an accuracy of <15 μm in a ±2 mm range of eye
movements with a standard deviation <10 μm, and requires less than 12 ms for each
detection. PTS can tolerate ±5 mm defocus with an increase of 4 μm in mean standard
deviation. In vivo measurements done with two subjects after their pupils are temporarily
paralyzed have resulted in a precision of 13 μm.
10:30 – 11:00
Thorlabs Refreshments break
31
SESSION 10
Imaging the Eye I
Chair: Christopher Dainty
11:00 – 11:30 Invited: Simultaneous SLO/OCT Imaging of the
Human Retina in vivo with High Speed Axial Eye Motion
Correction
M. Pircher, E. Götzinger, B. Baumann, H. Sattmann and C.K. Hitzenberger
Center for Biomedical Engineering and Physics, Medical University of Vienna, Austria
Transversal scanning (or en-face) optical coherence tomography (TS-OCT) represents an
imaging modality that is capable to record high isotropic resolution images of the human
retina in vivo. However, axial eye motion still remains a challenging problem of this
technique. In this paper we introduce an improved method of our previously published
axial eye motion correction technique. To measure accurately the position of the cornea an
auxiliary spectral domain partial coherence interferometer (SD-PCI) (operating at
1310nm) that is integrated into a TS-OCT system is used. The recorded corneal position is
used to drive a rapid scanning optical delay line in the reference arm of the TS-OCT
system to correct for axial eye motion. Currently, the correction can be performed with rate
of ~500Hz which is approximately 10 times faster than our previous system and practically
eliminates axial eye motion artifacts. The TS-OCT instrument is operated with a line scan
rate of 4000 transversal lines per second which enables simultaneous SLO/OCT imaging at
a frame rate of 40fps.
11:30 – 11:45 High-Speed High-Resolution Optical Coherence Tomography at 800
and 1060 nm
B. Považay, B. Hofer, B. Hermann, C. Torti, V. Kajić A. Unterhuber, W. Drexler
School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
Purpose:
To evaluate the feasibility of clinical high and ultrahigh-resolution optical coherence
tomography (OCT) devices for retinal imaging at different wavelengths, capable of
isotropic sampling with 70 to 500 frames per second at 512 depth scans/frame.
Methods:
Ophthalmic high-speed OCT systems have been designed with novel high-speed line
cameras, capable of acquiring more than 70 frames per second at 1060 nm and >300 fps at
800 nm respectively. A broad bandwidth amplified spontaneous emission (ASE) and a
specially designed ultra-broadband Ti:Sapphire laser based on all chirped specialty
mirrors have been set up, delivering <7 μm (at 70 nm bandwidth FWHM) and <3 μm
(>150 nm) axial resolution respectively. Both were integrated to clinical OCT systems to
retrieve densely sampled three-dimensional sections of the human fundus in vivo.
32
11:45 – 12:15 Invited: Revealing fine microstructural
morphology in the living human retina using optical
coherence tomography with pancorrection
C. Torti1, B. Povazay1, B. Hofer1, A. Unterhuber1, B. Hermann1, V. Kajic1, P. Ahnelt2,
E.J. Fernandez3, and W. Drexler1
1 Biomedical Imaging Group, School of Optometry & Vision Sciences, Cardiff University,
Wales, UK
2 Department of Physiology, Medical University of Vienna, Austria
3 Laboratorio de Optica, Universidad de Murcia, Campus de Espinardo (CiOyN), Spain
1. Purpose
To obtain enhanced visualisation of retinal morphology using ultra-high resolution OCT
with pancorrection, providing a very powerful tool for the early diagnosis of retinal
pathologies.
2. Methods
The light source is a Ti:Sapphire laser emitting a spectrum of 140-240 nm FWHM centred
at 800 nm. The achromatic blur of the eye is corrected statically using a custom
achromatizing lens while the monochromatic aberrations are corrected dynamically using
adaptive optics (AO) with a closed-loop bandwidth of 8 Hz. The spectrometer utilises a
transmissive grating and a high speed CMOS camera capturing volumetric tomograms at
a line rate of 120 kHz (240 fps). Post-processing techniques including registration using
cross-correlation, and a Gaussian wavelet filter are employed to account for motion
artifacts and to reduce noise.
12:15-13:45
Lunch
SESSION 10
Adaptive Optics II
Chair: Donald T. Miller
13:45 – 14:30 Invited: Applications of Adaptive Optics in
ophthalmology
Fabrice Harms, Imagine Eyes, Paris, France
http://www.imagine-eyes.com
Overview of AO in ophthalmology , Ocular wavefront sensing, Adaptive optics visual
simulation, Adaptive optics retinal imaging, Adaptive optics in corneal femtosecond lasers
33
14:30 – 14:45 Optimization of the Temporal Performance of a Deformable Mirror
for Use in Ophthalmic Applications
1,
2
Erika Odlund , Xavier Levecq2; Franck Martins2, Maurice Navarro2, Emeric Lavergne3,
Adrian Podoleanu1
1Applied Optics Group, School of Physical Sciences, University of Kent, Canterbury, United
Kingdom, 2Imagine Eyes, Orsay, France, 3Imagine Optic, Orsay, France
Adaptive optics (AO) is used to correct the wavefront aberrations of optical light beams in
real-time. An AO system is principally made up of three parts ; a measuring device, a
correction device, and a control algorithm to compute the residuals between the measured
and a reference wavefront. Deformable mirrors (DM) are commonly used as the correction
devices in such a system.
This paper presents a method to improve a DM’s time performance by attenuating
undesired oscillations of its reflective membrane when applying signals to the mirror
actuators. The method consists of implementing low-pass filtering into the software
driving the mirror. Different filtering functions were studied both when stimulating one
single actuator, and when applying voltages to the complete array of actuators. A linear
decomposition in 41 substeps showed the best performance for all considered
configurations. The obtained results represented an important reduction of the settling
time as well as for the overshoot in the signal response.
14:45 – 15:00 First steps toward 3D high resolution imaging using adaptive optics
and
full-field optical coherence tomography
Marie Blaviera, Leonardo Blancob, Florence Pouplarda, Sarah Ticka, Marie Glancb, Ivan
Maksimovica,
Gérard Roussetb,c, Michel Pâquesa, Jean-François Le Gargassona, Alain José Sahela
aCentre
d’Investigations Cliniques du CHNO des Quinze-Vingts, Université Paris VI,
France
bPHASE/LESIA Observatoire de Paris, UMR CNRS 8109, 5 place Janssen 92190 Meudon,
France
cPHASE/LESIA Université Paris VII, 5 place Janssen 92190 Meudon, France
dPHASE/DOTA ONERA, BP 72, 29 avenue de la Division Leclec, 92322 Châtillon cedex,
France
We describe here two parts of our future 3D fundus camera coupling Adaptive Optics and
full-field Optical Coherence Tomography. The first part is an Adaptive Optics flood imager
installed at the Quinze-Vingts Hospital, regularly used on healthy and pathological eyes. A
posteriori image reconstruction is performed, increasing the final image quality and field
34
of view. The instrument lateral resolution is better than 2 microns. The second part is a
full-field Optical Coherence Tomograph, which has demonstrated capability of performing
a simple kind of “4 phases” image reconstruction of non biological samples and ex situ
retinas. Final aim is to couple both parts in order to achieve 3D high resolution mapping of
in vivo retinas.
15:00 – 15:30 Invited: Challenges and possibilities for
developing adaptive optics - ultra-high resolution optical
coherence tomography for clinical in vivo retinal imaging
Robert J. Zawadzki, Stacey S. Choi, Julia W. Evans, and John S. Werner
Vision Science and Advanced Retinal Imaging Laboratory (VSRI) and Dept. of
Ophthalmology & Vision Science,
University of California Davis, 4860 Y Street, Suite 2400, Sacramento, California 95817
[email protected]
Recent developments in adaptive optics - optical coherence tomography (AO-OCT) allow
for ultra-high isotropic resolution imaging of in-vivo retina, offering unprecedented insight
into its volumetric microscopic and cellular structures. In addition to this promising
achievement, the clinical impact and application of this technology still needs to be
explored. This includes assessment of limitations and challenges for existing as well as
future AO-OCT systems, especially in the context of potential transfer of this technology
from an optical bench to a portable imaging system. To address these issues we will
describe our current UHR AO-OCT focusing on all its sub components, as well as
application for clinical imaging. Additionally, we describe some directions for future
development of our AO-OCT instrument that would improve its clinical utility including:
new compact AO-OCT design, new improved OA sub-system (extreme AO), and new
generations of FD-OCT.
15:30-16:00
Imagine Eyes Refreshments Break
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SESSION 12
Imaging the eye II
Chair: Wolfgang Drexler
16:00 -16:45 Invited: Optical Coherence Tomography for the
Investigation of Posterior and Anterior Eye Segments
Yoshiaki Yasuno, Computational Optics Group in the University of Tsukuba, Tsukuba,
Ibaraki, Japan
Since the first invention of optical coherence tomography (OCT), this technology has been
intensively employed in the ophthalmology, especially for the purpose of the investigation
of posterior eye. Recent development of Fourier domain (FD-) OCT technology enabled the
three-dimensional (3-D) investigation of the posterior eye not only in a laboratory but also
in a clinic. Currently several groups are also working for the application of FD-OCT to the
3-D investigation of the anterior eye. Another attempt to improve the OCT technology is
the introduction of new contrast technique including Doppler OCT and polarization
sensitive OCT. In this presentation, the author describes the 3-D investigation of the
anterior and posterior eye by FD-OCT and new clinical findings obtained by the
application of Doppler OCT and polarization sensitive OCT to the ophthalmology.
16:45 - 17:00 Anterior Segment Imaging Using High Speed Swept Source OCT
K.M. Karnowski1, M. Gora1, D. Szlag1, B.J. Kaluzny2,
R. Huber3, A. Kowalczyk1, M. Wojtkowski1
1Institute of Physics, Nicolaus Copernicus University, Torun, Poland;
2Dept of Ophthalmology, Collegium Medicum UMK, Bydgoszcz, Poland;
3Dept of Physics, Ludwig-Maximilians University, Munich, Germany.
To present applicability of high speed swept-source optical coherence tomography
(SS-OCT) to in vivo imaging of the anterior segment of the eye. High speed imaging
enables volumetric imaging of the entire anterior segment. An anterior and posterior
surface of the cornea can be extracted with decreased number of motion artifacts, which is
beneficial in corneal topography and thickness maps recovering.
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17:00 – 17:15 Full-range, high-speed, high-resolution 1 μm spectral-domain
optical coherence tomography with BM-scan method for the human posterior
eye imaging
1
Shuichi Makita , Tapio Fabritius1,2, Masahiro Miura3,1, Yoshiaki Yasuno1
1Computational Optics Group in the University of Tsukuba, Tsukuba, Ibaraki, Japan.
2Optoelectronics and Measurement Techniques Laboratory, University of Oulu, 90014
University of Oulu, Finland.
3Depertment of Ophtahlmology, Tokyo Medical University, Kasumigaura Hospital,
Inashiki, Ibaraki, Japan.
An alternative optical coherence tomography (OCT) to clinical ophthalmic 840 nm
spectral-domain OCTs (SD-OCT) is demonstrated. An axial resolution of 7.4 μm, ranging
depth of 4.2 mm in tissue, sensitivity of 94.4 dB, and detection speed of 46,900 axial scans/s
have been achieved. These are comparable or superior to those of recently commercially
available ophthalmic 840 nm SD-OCTs in clinics. In addition, fast volumetric imaging for
the in vivo human posterior eye with high-contrast of the choroid is achieved. A broadband
1.04 μm light source enables the high-contrast and high resolution imaging of the retina
and choroid. The ranging depth is extended by applying a full-range imaging method with
an electro-optic modulator (BM-scan method). A sensitivity improvement property of the
BM-scan method demonstrates a sensitivity enhancement of 4.4 dB. The threedimensional
structure of the in vivo human optic nerve head with a very deep cupping is successfully
visualized. In the comparison to a commercial SD-OCT system in the patient with type II
choroidal neovascularization, the lower extinction of signals and the high contrast in the
choroid is achieved.
17:15-19:00
Posters Session 2 and Farewell drinks
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LIST OF POSTERS
Poster 1: An Adaptive Optics Assisted Retinal Imaging System using a Pyramid
Wavefront Sensor
Sabine Chiesa and Chris Dainty
School of Physics,
National University of Ireland, Galway, Ireland
[email protected]
A breadboard retinal imaging system that incorporates adaptive optics is being
constructed. It comprises four sub-systems for: (i) pupil alignment, (ii) wavefront sensing,
(iii) retinal illumination and (iv) retinal imaging. Control and data acquisition is carried
out through LabView. The system is designed to be flexible for use in laboratory-based
clinical studies.
Poster 2: Measurements of the optical aberrations within a 10deg field in the eye
Maciej Nowakowski, Alexander Goncharov, Chris Dainty
Applied Optics Group, School of Physics, National University of Ireland, Galway, Ireland
([email protected])
The human eye is far from being a perfect optical system and in addition to the usual
refractive errors it suffers from high-order aberrations like coma, trefoil, spherical
aberration and others. Little is known about how these aberrations vary across the visual
field of view.
The nature of aberrations is complex mainly due to the lack of rotational symmetry of the
eye, irregular shape of the cornea and gradient-index lens structure (GRIN) of the
crystalline lens. A study of ocular aberrations, their field dependence and statistical
distribution within young population is the main objective of this project.
We investigated 15 eyes of the population of young and healthy subjects without any optical
abnormalities under cycloplegia conditions. The wavefront aberrations were measured
along horizontal and vertical meridians up to ±5 deg visual field with an aberrometer
consisting of Shack-Hartmann (SH) wavefront sensor. We found that the dominant
contributors to the total RMS of the off-axis wavefront error (i.e. wavefront off-axis minus
wavefront on-axis) are astigmatism and defocus (about 80% of the total RMS error). Thus a
significant improvement in retinal imaging quality over a large field might be achievable by
correcting astigmatism and defocus using suitable optical methods, plus a deformable
mirror (DM) to correct on-axis aberrations. We also found that some higher order
aberrations (e.g. spherical and trefoil coma) show no significant variation with the field
angle indicating a single DM optically conjugated to the pupil can remove their contribution
from the entire field.
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Poster 3: Multi-Channel Time Domain Spectroscopic Optical Coherence
Tomography System
Alexander Meadway, Seyed Hamid Hosseiny Darbrazi, Ramona Cernat, Michael Hughes,
George Dobre, Adrian Gh. Podoleanu
Applied Optics Group, School of Physical Sciences, University of Kent, CT2 7NH, UK
Richard Rosen
Advanced Retinal Imaging Center, New York Eye and Ear Infirmary
New York, New York 10003, USA and New York Medical College, Valhalla, New York,
10595, USA
A detection method based on 7 spectral windows at the photodetection stage is tested. We
investigate its utility into two directions: spectroscopic optical coherence tomography
(OCT) and signal to noise ratio improvement. A diffraction grating is used in the
photodetection unit to diffract light over a 16 photodetector array cells. For the moment,
this array is configured to deliver 7 channels only, by binning two adjacent photodetectors.
Improvement of the S/N ratio has been demonstrated using a mirror. Preliminary results
of spectroscopy analysis will be shown by performing B-scan imaging on different paint
layers. The main goal is to perform spectroscopic analysis of the retina.
Poster 4: Towards a compact coherence-gated wavefront sensor for microscopy
S. Gigan*, V. Loriette and A. C. Boccara
Laboratoire d’Optique Physique de l’ESPCI, LPEM UPR5 du CNRS, UPMC, INSERM,10,
rue Vauquelin - 75 231 Paris Cedex 05 (France)
Optical microscopy is an inescapable technique in the life sciences, in particular for
studying the intracellular organization of biochemical events. However, there is an
increasing need in a variety of fields (neurophysiology, developmental biology, biopsy) to
image cells in their native environment, i.e. intact tissue. The task is difficult because
tissues are heterogeneous media that strongly affect light propagation, causing large
amounts of scattering and wavefront aberration at large depths. These effects reduce
resolution and contrast in optical techniques (such as confocal and 2 photon microscopy),
and prevent them to provide images deep within intact tissue. Ideally, aberration
correction requires measuring the wavefront distortion induced along the path to the
focus. This can be realized by combining coherence-gated detection (OCT like) of the light
backscattered by the sample and wavefront sensing. We will describe our ongoing effort to
develop robust aberration correction techniques for multiphoton and OCT imaging of thick
tissues.
39
Poster 5: Optical coherence tomography and confocal microscopy investigations
of dental prostheses
Meda L.Negrutiua, Cosmin Sinescua, Michael Hughesb, Adrian Bradub, Mihai Rominua,
Carmen Todeac, George Dobreb and Adrian Gh. Podoleanub
Department of Prostheses Technology and Dental Materials, Faculty of Dental Medicine,
University of Medicine and Pharmacy "Victor Babeş" Timişoara, Romania
bApplied Optics Group, School of Physical Sciences, University of Kent, Canterbury, UK
c Department of Oral Rehabilitation and Dental Emergencies, Faculty of Dental Medicine,
University of Medicine and Pharmacy "Victor Babeş" Timişoara, Romania
d Department of Strength of Materials, Politehnica University Timişoara, Romania
a
Dental prostheses are very complex systems, heterogenous in structure, made up from
various materials, with different physical properties. An essential question mark is on the
physical, chemical and mechanical compatibility between these materials. They have to
satisfy high stress requirements as well as esthetic challanges. The masticatory stress
may induce fractures of the prostheses, which may be triggered by initial materials defects
or by alterations of the technological process. The failures of dental prostheses lead to
functional, esthetic and phonetic disturbances which finally render the prosthetic
treatment inefficient. The purpose of this study is to evaluate the capability of en-face
optical coherence tomography as a possible non-invasive high resolution method in
supplying the necessary information on the material defects of dental prostheses and
microleakage at prosthetic interfaces. C-scan and B-scan OCT images as well as confocal
images are acquired from a large range of samples. Gaps between the dental interfaces and
material defects are clearly exposed. We conclude that OCT can successfully be used as a
noninvasive analysis method.
Poster 6: An Innovative Approach for Investigating the Ceramic
Bracket-Enamel Interface – Optical Coherence
Tomography and Confocal Microscopy
Roxana Otilia Romînu1, Cosmin Sinescu1, Mihai Romînu1, Meda Negruþiu1, Phillippe
Laissue2, Sorin Mihali3, Michael Hughes4, Adrian Bradu4, Adrian Gh. Podoleanu4
1
“Victor Babes” University of Medicine and Pharmacy, School of Dentistry, Department of
Prosthetic Technology and Dental Materials
2 Kent Institute of Medical Science, University of Kent, Canterbury, UK
3 “Victor Babes”University of Medicine and
Pharmacy Timisoara, School of Dentistry
4 Applied Optics Group, School of Physical Sciences, University of Kent, Canterbury, UK
In many fields of dentistry, the investigation of different bonded interfaces is widely used
since bonding has become routine procedure in several dental specialties – from
prosthodontics to conservative dentistry and even orthodontics. Up until now all known
40
investigation methods are invasive which means that samples are destroyed and no longer
of use during and after testing. In our study we investigated the interface between human
enamel and bonded ceramic brackets from a new perspective, introducing a combination of
new, non-invasive investigation methods – optical coherence tomography (OCT) and
confocal microscopy. Brackets were conventionally bonded on the conditioned buccal
surfaces of the teeth. The samples were assessed using the above mentioned methods.
Poster 7: Combining Optical Coherence Tomography and Confocal Microscopy
Investigation of the defects inside the Ceramic Fixed Partial Dentures
Cosmin Sinescu1, Meda Negrutiu1, Mihai Romînu1, Phillippe Laissue2, Cezar Clonda3,
Michael Hughes4,
Adrian Bradu4, George Dobre4, Adrian Gh. Podoleanu4
“Victor Babes” University of Medicine and Pharmacy,School of Dentistry, Department of
Prosthetic Technology and Dental Materials
2 Kent Institute of Medical Science, University of Kent, Canterbury, UK
3“Victor Babes” University of Medicine and
Pharmacy Timisoara, School of Dentistry
4 Applied Optics Group, School of Physical Sciences, University of Kent, Canterbury, UK
1
Combining the optical coherence tomography with the confocal microscopy investigations
represent the next level in identification of materials defects inside the ceramic layers of
the fixed partial dentures located in the most stressful zones. All-ceramic fixed partial
dentures (FPDs) have an aesthetic approach for oral rehabilitation. However,
metalceramic FPDs are best indicated in the posterior area where the follow-up studies
found a lower failure rate. The results pointed out the necessity of a good non-invasive
method in order to identified the critical spots in a ceramic fixed partial denture before
inserting in the oral cavity in order to avoid the failure of the prosthetic treatment.
Poster 8: Improvement of the mode quality in Large Mode Area (LMA) fibres
Stefan Grünsteidl1,2, JM Sousa1, Ger O’Connor2, Tom Glynn2
1Multiwave Photonics, Porto, Portugal
2NCLA, National University of Ireland, Galway, Ireland
[email protected]
Using an offset-launch technique and near-field-imaging, we studied the modal
distribution of light on LMA fibres in different launch conditions for different fibres. We
also developed novel coiling techniques to improve the higher order modes suppression and
to lower the fundamental mode loss. These results will be applied on a pulsed high power
fiber laser, that will be later tested for materials processing applications.
41
Poster 9: Development and characterisation of laser ablative process for
synthesis of nanoparticles.
Sujith Manjooran
School of Physics, National University of Ireland – Galway, Galway, Ireland
Engineered nanoparticles offer many new applications in optical, electronic, and chemical,
and healthcare sectors. While there are many methods for producing nanoparticles, no
single technique has emerged that is capable of producing nanoparticles in high volumes
that have a mono-disperse size distribution. Short-pulse laser technology offers some
potential to cost effectively produce nano-scale particles from a bulk material. This paper
investigates this process and describes a laser ablative cell which is under-development
that will produce and characterise nano-particles from bulk materials in novel ambients.
Poster 10: Multiple Delay Lines Full-field Optical Coherence Tomography
Jingyu Wanga, Christopher Daintyb, Adrian Podoleanua
a Applied Optics Group, School of Physical Sciences, University of Kent,
Canterbury, Kent, UK
b National University of Ireland, Galway, Ireland
Full-field Optical Coherence Tomography (FF-OCT) is a kind of parallel detection OCT
technique, with which samples are illuminated in full field of view and imaged with the
help of a 2D sensor array. With relatively low NA optics, large images and depth of view
can be obtained from FF-OCT. This configuration is also known as coherence radar, which
is widely used to image reflective surfaces. A novel feature is investigated to be
implemented in FF-OCT. This consists in a Multiple Delay Element (MDE) which can be
inserted into the optical source path or the reference path. This is useful in providing
topography information in one frame on the expense of in-depth information from the
object which is discarded. The reflections from the surface of the object are considerably
larger compared to the back-scattering light from inside of the sample; therefore a FF-OCT
frame will present several contours superposed on a scattering background due to the
internal structure of the sample. The relative height of the object surface points are infered
from the multiple contours generated by the delays in the MDE. We have assembled a
FF-OCT system which incorporates an MDE. to evaluate the topography of curved objects
in a single shot imaging. We evaluate the optimum combination of the MDE principle with
the FF-OCT method in general and assess two possibilities: (i) MDE in the optical source
path and (ii) in the reference path. FF-OCT uses full-field illumination and 2D detector
array and in this way eliminates the need for transverse electromechanical scanning,
which slows the imaging process and gives rise to motion artefacts due to mechanical jitter
and limited repeatability. This study is a preliminary step in extending the technique to
the human cornea.
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Poster 11: En-face OCT system at 1060 nm
Liviu Neagu1, Antonio B. Lobo Ribeiro2, Jose Salcedo2, Adrian Bradu1, Lisha Ma3, Jim
Bloor3, Adrian Podoleanu1
1 Applied
Optics Group, University of Kent, Canterbury, UK
2 Multiwave Photonics, Porto, Portugal
3 Department of Biosciences, University of Kent, Canterbury, UK
A microscope system has been devised which implements a dual channel OCT and confocal
microscope. The configuration is driven by a novel broadband fibre source centred at 1060
nm wavelength (Multiwave Photonics). The dual channel configuration has been designed
and constructed to acquire live images from scattering biological samples. The
configuration consists in an optical circulator and at least two couplers in a symmetric
arrangement for the object and reference arm. The OCT channel microscope is based on a
Mach-Zehnder interferometer configuration. Each arm of the interferometer contains an
in- fibre acousto-optic modulator. One of the in-fibre acousto-optic modulator is driven at a
fixed frequency of 40 MHz and the other via an RF Function Generation, with adjustable
frequency. In this way, the carrier frequency can be conveniently changed in the range 100
kHz to 1.5 MHz. Light retroreflected by the sample is sent to a balanced coupler where it
interferes with the reference beam. The interference signal is photodetected using two
photodetectors followed by a differential amplifier.
Poster 12: Development and Optimization of Fibre Optic Broadband Sources at
1 micron region for Optical Coherence Tomography
I. Trifanov, A.G. Podoleanu(a), J.R. Salcedo and A.B. Lobo Ribeiro
Multiwave Photonics S.A., R. Eng. Frederico Ulrich 2650, 4470-605 Moreira da Maia,
Portugal
(a) Applied Optics Group, School of Physical Sciences, University of Kent, Canterbury, Kent
CT2 7NH, UK
Recent developments on broadband optical sources emitting at 1050 nm wavelength for
medical applications, in particular optical coherence tomography (OCT), have revealed
enhanced depth penetration into the choroid, reduced scattering losses and improved
image performances in eyes with turbid media, when compared to the most commercial
used semiconductor optical source technology at 820 nm.
In this paper, we present our ongoing work on the development of fibre optic broadband
sources (BBS) at 1 micron region, based on the amplified spontaneous emission (ASE) from
rare-earth doped silica fibres for the integration into OCT systems. Our target
specifications for this type of sources are: 1050 nm central emission wavelength, with
spectral linewidths of ~70 nm (full-width at half maximum), tens of miliwatts of output
43
power and smoothly shaped output spectra. Several combinations of rare-earth doped
optical fibres integrated into different fibre optic configurations have been tested. Optical
bandwidth optimization and spectral shaping using different fibre optic techniques are
presented and their autocorrelation function compared.
Poster 13: High-resolving full-field OCT system for investigation of random
tissues
Igor Gurov, Anna Umanets, Maxim Volynsky
Saint Petersburg State University of Information Technologies, Mechanics and Optics
49 Kronverksky ave., Saint Petersburg, 197101, Russia
E-mail: [email protected]
High-resolving full-field OCT method is considered that provides increased resolution and
interferometric data acquisition speed due to high optical magnification and electronic
lateral scan provided by video camera. OCT data processing method based on Kalman
filtering algorithm is considered. Experimental results obtained when evaluating samples
of random tissues are presented and discussed.
Poster 14: In-vitro and in-vivo OCT image contrast.
N Krstajic, J Jacobs, L Smith, P Deshpande, S MacNeil, R Smallwood, SJ Matcher
Biomedical Engineering, The Kroto Institute, University of Sheffield, Broad Lane, Sheffield
S3 7HQ
We present results of OCT and polarization-OCT imaging applied to various in-vitro
tissue samples and discuss related issues of image contrast, comparing in-vivo and in-vitro
preparations.Time-domain and frequency-domain OCT at 800nm and 1300nm has been
applied to ex vivo human skin and rabbit cornea. We can distinguish rabbit cornea
epithelium for up to a month after excision, however, the skin loses all contrast upon
excision and despite numerous experiments we cannot distinguish epidermis, which is
clearly visible in vivo. The effects of different tissue sample and preservation strategies on
image contrast are explored. We have also applied polarization-OCT for the first time, to
our knowledge, to bone tissue. Using a time-domain system, birefringence is clearly visible
for decalcified tissue but can also be detected more weakly on fully mineralised tissue.
Analysis suggests that demineralisation increases the birefringence value.
44
Poster 15: Quasi–sequential operation of en-face OCT and CM(SLO)
synchronous with the transversal scanner
Irina Trifanov1,2, Michael Hughes, Adrian.Gh. Podoleanu,
of Kent, School of Physical Sciences, Applied Optics Group,
Canterbury,CT2 7NH, United Kingdom
2Multiwave Photonics S.A., R. Eng. Frederico Ulrich 2650, 4470-605 Moreira da Maia,
Portugal
1University
Richard B. Rosen
Advanced Retinal Imaging Center, New York Eye and Ear Infirmary, New York, New York
10003 and New York Medical College, Valhalla, New York 10595
A new approach of acquiring quasi-simultaneous optical coherence tomography _OCT_
and confocal images is presented. The two images are generated using different principles,
OCT and confocal microscopy. The acquisition and display of en face OCT and confocal
images are quasi-simultaneous, without the need of a beamsplitter. By using a chopper to
periodically obstruct the reference beam in the OCT interferometer, synchronized with the
XY-transversal scanner, much higher acquisition speed is obtained than in a previous
report where we flipped an opaque screen in the reference arm of the interferometer.
Successful operation of the novel configuration was achieved by stable synchronization of
the chopper’s movement with the horizontal line scanner and fast self-adjusting of the gain
value of avalanche photodiodes, depending on the optical power. Images from coin, leaves,
and retina in vivo have been collected to demonstrate the functionality of the system.
Poster 16: Nanoparticles for Enhanced Contrast Optical Coherence
Tomography
César Maule1a,b, Michael Leitner a,b,c, Pedro A. S. Jorgeb, N.Sooraj Hussainb, Gerardo G.
Aguilac, Carla C. Rosaa,b
a Physics Department, Faculty of Science, University of Porto, Rua do Campo Alegre, 687,
4169-007 Porto, Portugal
b Optoelectronics Unit, INESC Porto, Instituto de Engenharia de Sistemas e
Computadores-Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
c Applied Optics Group, School of Physical Sciences, University of Kent, Canterbury
CT2 7NH, UK
Recently the area of bioimaging has beneficiated from a new type of image enhancing
agent such as quantum dots, carbon nanotubes and other nanoparticles. Cellular or even
molecular level resolution has been achieved with different techniques during these last
years (i.a. Fluorescence microscopy, PET/CT scan, AFM). Optical Coherence Tomography
(OCT) as an imaging technique should also take profit from newly developed probes. In
this work we aim to explore the tunable properties of different types of nanoparticles as
contrast enhancers in OCT applications. We will mainly study the development and
45
characteristics of different nanoparticles, such as tunable gold nanoshells, rare-earth
doped lithium boro tellurite glasses and rare-earth doped solgel nanoparticles. We will
discuss nanoshell and nanoparticles processing techniques and their optimization for
designing particles with specific absorption and scattering characteristics, and its use in
OCT imaging.
Poster 17: Imaging of basal cell carcinoma tissue using en-face OCT
Bhanu Rakesh Penmetsa1, Mona Khandwala2, Adrian Bradu1, Michael Hughes1, Carole A.
Jones2, John Schofield2, George Dobre1, Adrian Gh. Podoleanu1
1Applied
Optics Group, University of Kent, Canterbury CT2 7NH, UK
2 Maidstone and Tunbridge Wells NHS Trust
En-face OCT was used to image tumour tissue excised from 8 patients, all with biopsy
proven basal cell carcinoma (BCC) of the periorbital region. The samples were fixated and
markers have been applied to ensure correlation with the histology. The samples were
stored in formaldehyde and the scans performed with occasional hydration with drops of
formaldehyde. The samples were imaged in C scan and B scan mode in three different OCT
machines: (i) operating at 1300 nm, 9 mm image size; (ii) operating 1300 nm, 1.5 mm
image size, equipped with a confocal microscope at 970 nm and (iii) operating at 840 nm
and 5 mm image size. Better penetration was obtained at 1300 nm as expected. Results
will be presented of comparisons of images with histology.
46