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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). 1 3 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 4 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 6 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 7 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 8 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 9 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 11 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 12 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. 13 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 14 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 15 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. 16 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 5106W/cm2 were investigated. Single spatial mode samples with 4m-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 20-30m 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 35 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. 36 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 37 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. 38 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. 42 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