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Advanced Applications
Our advanced applications team develops complete
systems by integrating components from a broad
range of suppliers. These setups are designed
and built by an interdisciplinary team of engineers,
scientists, and collaborators with the purpose of
allowing users to quickly get familiar with specific
photonics technologies. Their ease of use and
adaptability makes these systems ideal tools for
advanced teaching labs and allows researchers
to save time by using these systems as the
initial building blocks for the construction of more
complex systems.
For more information about our
custom capabilities and support,
contact our Advanced Applications
Team at 973-300-3000 or email us
at [email protected].
Optical Tweezers Setup
Magneto-Optical Trap Setup
1804
www.thorlabs.com
Advanced Applications
Selection Guide
Frequency
Atomic ForceOpticalOptical Delay
StablizationMicrosocpeTweezersLine
Suercontinuum
Pages XXX - XXX
Pages XXX - XXX
Pages XXX - XXX
Pages XXX - XXX
Pages XXX - XXX
Frequency Stabilization
Selection Guide
Dichroic Atomic Vapor Spectroscopy
Pages XXX - XXX
Saturated Absorption Spectroscopy
Pages XXX - XXX
Stabilized Laser Systems
Pages XXX - XXX
Magneto-Optical Trap
Pages XXX - XXX
Proportional and Integral Feedback Controller
Page XXX
Since this portion of our product line is rapidly expanding, we
ask that you look for frequent updates at www.thorlabs.com
and search on Advanced Applications.
www.thorlabs.com
1805
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Dichroic Atomic Vapor Spectroscopy (Page 1 of 2)
Features
Optical Tweezers
n
Optical Delay Line
n
Supercontinuum
n
DAV Spectroscopy
SA Spectroscopy
Complete Stabilized
Laser Systems
MOT Application
Dichroic Atomic Vapor Spectroscopy
PI Feedback
Controller
Dichroic Atomic Vapor Spectroscopy (DAVS) utilizes the Zeeman
effect to create a signal suitable for laser locking. A Rubidium or
Potassium vapor cell is placed in a weak longitudinal magnetic field.
Laser light travels through a Glan-Taylor Polarizer prior to entering
the vapor cell, thereby ensuring that the input is linearly polarized.
Due to the presence of the weak magnetic field, the absorption profiles
of the two circular components (+ and -) that comprise the linearly
polarized input beam are shifted to higher and lower frequencies,
respectively. After passing through the vapor cell, the beam propagates
through a quarter-wave plate and a polarizing beamsplitter (Wollaston
prism). The dispersion-like curve generated from the difference
between the two signals (as shown in the graph to the right), provides
an error signal for the frequency lock.
The quarter-wave plate placed after the vapor cell can be rotated so as
to alter the intensities of each component as well as the zero crossing
of the error signal. This in turn allows for the frequency of the tunable
laser to be shifted to higher or lower values. Tuning of the laser lock is
very useful for applications such as magneto-optical trapping (see page
XXX).­­­­­
Thorlabs’ frequency stabilization system offers a turn-key
method for producing a highly stable lock for tunable
lasers. The laser frequencies that our spectroscopic systems
are capable of stabilizing are dependent upon the atomic
transition frequencies of the reference gas used. Currently,
we offer Rubidium and Potassium versions. A variety of
custom reference cells are also available; please contact
[email protected] for more details. Due to the
method of signal generation, the Dichroic Atomic Vapor
Spectroscopy System provides the additional benefit of
being able to detune the locking frequency from the atomic
transitions.
DAVS Signal
3
2
Signal (a.u)
t SECTIONS
Allows Tuning of Locking Wavelength Off
of Transitions
Maintenance-Free, PM Fiber-Coupled Setup
Rb, K, or Custom Reference Cells Available
1
0
-1
87
Rb
85
85
Rb
87
Rb
Rb
-2
-2
-1
0
1
2
3
4
Relative Laser Frequency (GHz)
Absorption (a.u.)
Absorption (No Field)
Red-Shifted Absorption
Blue-Shifted Absorption
DAVS Signal
Using Dichroic Atomic Vapor Spectroscopy, a laser can be locked
to any of the zero crossings in the above signal. The circled zero
crossings correspond to transitions in atomic Rb, each of which can
be tuned by approximately 500 MHz.
Specifications
n
n
n
Frequency (a.u.)
In the absence of a magnetic field, the absorption profile is independent of
polarization, as shown by the red line in the graph above. After a magnetic field
is applied, the Zeeman shift can be observed for the two circularly polarized
components (refer to the green and blue lines). The useful DAVS Signal is the
difference between the absorption profiles of these two components.
1806
www.thorlabs.com
n
n
n
n
Long-Term Stability: <2 MHz (RMS)
Required Input Power: ~100 µW
Input Fiber Termination:* FC/PC
Wide Capture Range: ~500 MHz
Detector Bandwidth: 1 MHz
Detector Output Range: ±10 V
Reference Cell can be Heated to 50 ºC
*Alternate Fiber Inputs Available
Advanced
Applications
CHAPTERS
Dichroic Atomic Vapor Spectroscopy (Page 2 of 2)
Rubidium or Potassium
Vapor Cell
Glan-Taylor Polarizer
Balanced
Detector
Wollaston Prism
λ/4
Magnet
Optical Tweezers
DAVS Schematic
+
Simplified optical schematic
of the DAVS system that is
embedded in the enclosure
shown on the previous page.
–
t
Frequency
Stabilization
Atomic Force
Microscope
Optical Delay Line
Supercontinuum
SECTIONS t
Magnet
DAV Spectroscopy
SA Spectroscopy
1.5
MOT Application
1
PI Feedback
Controller
0.5
0
-0.5
-1
-1.5
-2
0
Electronic
Spectrum
Analyzer
100
200
300
400
500
600
Time (minutes)
Photodetector
SV2-FC
Complete Stabilized
Laser System
FLK-DAV-TLK-RB
(Tuned to 87Rb Transition)
Complete Stabilized
Laser Systems
Rb-85 vs Rb-87 D2
2
Beat Frequency Drift (MHz)
Tests of the DAVS system’s ability to maintain frequency
stabilization revealed that the laser’s long-term drift was <2 MHz
RMS. During the experiment, one tunable laser kit (see page XXX)
was stabilized by a Dichroic Atomic Vapor Spectroscopy Kit
(FLK-DAV-RB) to the 85Rb D2 transition, while a second
tunable laser was stabilized by another DAVS system to the 87Rb
line (see the schematic below). The output beams from the lasers
were spatially overlapped and coupled into a fiber. The beat note
between the two lasers was recorded using an SV2-FC (page XXX)
fast photodetector and analyzed using an electronic spectrum
analyzer.
Complete Stabilized
Laser System
FLK-DAV-TLK-RB
(Tuned to 85Rb Transition)
The results shown in the graph above depict the drift in the beat
frequency over a period of 10 hours. As seen, the beat frequency
drift was less than 2 MHz RMS. What should be noted is that
the most probable cause of the drift was temperature change.
Temperature shifts throughout the test period change the
birefringence of the gas cell windows. This in turn will affect the
signal intensity of the two light polarizations, thereby impacting
the frequency stability of the lock.
ITEM #
FLK-DAV-RB
$
$ 5,800.00
£
£ 4,176.00
ERMB
DESCRIPTION
E 5.046,00
¥ 46,226.00
Dichroic Atomic Vapor Spectroscopy System, Rubidium
FLK-DAV-K
$ 5,800.00
£ 4,176.00
E 5.046,00
¥ 46,226.00
Dichroic Atomic Vapor Spectroscopy System, Potassium
Have you seen our...
Complete Stabilized Laser System
Thorlabs’ laser frequency stabilization
systems extend our line of Tunable
Laser Kits by providing an option for
stabilizing the laser output to an atomic
transition frequency. Stabilized light
sources are frequently used in atomic
physics applications such as the cooling
and trapping of atoms.
Included Components
◆Dichroic Atomic Vapor Spectroscopy System
◆Tunable Laser Kit, Housing, and Heater
◆Laser Diode Temperature and Current
Controller
◆IdestaQE’s Integral Feedback Controller
◆All Necessary Optics and Optomechanics
See pages XXX - XXX
www.thorlabs.com
1807
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Saturated Absorption Spectroscopy (Page 1 of 2)
Thorlabs’ frequency stabilization system offers a turnkey method for producing a highly stable optical lock
for a tunable diode laser. The laser frequencies that
our spectroscopic systems are capable of stabilizing are
dependent upon the atomic transition frequencies of the
reference gas used. Currently, we offer Rubidium and
Potassium versions. A variety of custom reference cells are
also available; please contact [email protected] for
more details. Saturated Absorption Spectroscopy resolves
the hyperfine structure of the atomic transition through
the elimination of Doppler Broadening, thus providing a
robust lock that is directly tied to an atomic transition.
Optical Tweezers
Optical Delay Line
Supercontinuum
t SECTIONS
DAV Spectroscopy
SA Spectroscopy
Complete Stabilized
Laser Systems
MOT Application
Saturated Absorption Spectroscopy
Thorlabs’ Saturated Absorption Spectroscopy Systems provide a means to
create a highly sensitive lock directly tied to an atomic transition. When
an atom absorbs (or emits) a photon, the absorption (emission) frequency
is Doppler shifted. The direction and magnitude of the shift with respect
to line center will depend on the atom’s velocity compared to that of the
photon. The Maxwell-Boltzmann velocity distribution in a thermal gas
is the cause of Doppler Broadening in Absorption Spectroscopy Signals.
To create a more narrow laser lock, Doppler Broadening is eliminated by
use of the well known Saturated Absorption technique that resolves the
hyperfine structure of atomic transitions.
To implement a Saturated Absorption system, a beamsplitter is used to
obtain two counterpropagating beams. The first beam, the pump beam,
is used to excite the atoms in a gas cell at a particular frequency. Near the
resonant transition frequency of the sample, more atoms will be pumped
into an excited state by this pump beam.
Rb Saturated Absorption Spectrum
1.6
Absorption (a.u.)
PI Feedback
Controller
1.4
1.2
1.0
0.8
0.08
0.10
0.12
0.14
0.16
0.18
0.20
Time (s)
The second beam, the probe beam, will go through the gas cell and be detected by one port of a balanced detector. The frequency of this
beam is identical to that of the pump beam but propagates in the opposite direction; thus the Doppler shift observed from this beam is of
opposite sign. Hence, only atoms with zero velocity will be in resonance with both the pump and probe beams. If the laser frequency is
in resonance with zero-velocity atoms, a drop in absorption of the probe beam is observed since the pump beam is depleting the number
of ground-state, zero-velocity atoms. This reduction in population is evidenced by the dips in the Doppler-broadened absorption profile
(refer to the plot above). By passing a third reference beam through the vapor cell so that it doesn’t overlap with the pump beam, the
balanced detector is used to subtract the Doppler broadened background. The resulting profile is shown on the next page.
Balanced
Detector
Rubidium or Potassium Vapor Cell
+
λ/2
Polarizing
Beamsplitter
Cube
Polarizing
Beamsplitter
Cube
4 µW
–
50/50
400 µW
1808
www.thorlabs.com
SAS Schematic
Simplified optical
schematic of the SAS
system that is embedded
in the enclosure pictured
at the top of this page.
Advanced
Applications
CHAPTERS
Saturated Absorption Spectroscopy (Page 2 of 2)
Features
n
n
n
n
n
Specifications
Eliminate Doppler Broadening using
Counterpropagating Beams
Allows Locking Directly to Transitions
Narrow Absorption Lines Provide Highly Sensitive
Feedback
Maintenance-Free, PM Fiber-Coupled Setup
Rb, K, or Custom Reference Cells Available
n
n
n
n
n
t
Frequency
Stabilization
Atomic Force
Microscope
Required Input Power: ~500 µW
Input Fiber Termination:* FC/PC
Detector Bandwidth: 1 MHz
Detector Output Range: ±10 V
Reference Cell can be Heated to 50 ºC
Optical Tweezers
Optical Delay Line
Supercontinuum
*Alternate Fiber Inputs Available
SECTIONS t
DAV Spectroscopy
SAS Signal
SA Spectroscopy
Difference Signal
0.22
Direct Transmission – Doppler-Free Transmission
MOT Application
0.14
Signal (V)
Signal (a.u.)
0.18
Complete Stabilized
Laser Systems
1.10
PI Feedback
Controller
V(f0)
V(f)
0.06
Doppler-Free Transmission
Direct Transmission
0.02
0.0
0.2
0.4
0.6
0.6
1.0
Frequency (f)
Time (s)
The Direct and Doppler-Free Transmission Spectra as detected
by the + and - ports of the balanced detector are shown above.
The difference between these two signals is then plotted to see
the narrow transition peaks.
To use these transition signals for laser frequency stabilization,
the laser is locked to a frequency corresponding to the sharp
edge of a transition peak. This side locking technique allows the
user to lock directly to the transition frequency. It can be seen
Do you
need an...
f f0
that there is a voltage V(f0) corresponding to a particular lock
point. As the laser frequency drifts, another voltage V(f) will be
produced. An error signal, calculated by Error(f) = V(f0) - V(f),
can then be used in a feedback loop to adjust the current
and grating angle, which controls the laser frequency, until
Error(f) = 0. In this manner, the laser frequency is locked directly
to the transition.
ITEM #
FLK-SAS-RB
$
$ 5,800.00
£
£ 4,176.00
ERMB
DESCRIPTION
E 5.046,00
¥ 46,226.00
Saturated Absorption Spectroscopy System, Rubidium
FLK-SAS-K
$ 5,800.00
£ 4,176.00
E 5.046,00
◆Heat-Treated Stainless Steel Minimizes
Temperature-Dependent Hysteresis to Less than
2 µrad Deviation after Temperature Cycling
◆Actuators Matched to Body/Bushing to Reduce
Drift and Backlash
◆Sapphire Seats Ensure Long-Term Durability
For more details,
see pages XXX - XXX
¥ 46,226.00
IR Viewing
Card
THORLABS
Detector Card
VRC2: 400 - 540 nm
800 - 1700 nm
Always take appropriate safety
precautions when working with lasers
See page
XXX
Saturated Absorption Spectroscopy System, Potassium
POLARIS-K05
POLARIS-K1
Mechanical and Temperature Test
Data at www.Thorlabs.com
POLARIS-K1-H
www.thorlabs.com
1809
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Complete Stabilized Laser Systems (Page 1 of 2)
Optical Tweezers
Includes Complete
System as Shown
(Breadboard Not Included)
Optical Delay Line
Supercontinuum
t SECTIONS
DAV Spectroscopy
SA Spectroscopy
Complete Stabilized
Laser Systems
MOT Application
PI Feedback
Controller
Features
n
n
n
n
n
Saturated Absorption Spectroscopy or
Dichroic Atomic Vapor Spectroscopy System
Included
~40 mW Output Power
from Tunable Laser
Frequency Stability Signal Processed by
IdestaQE's PI Feedback Controllers
Includes All Necessary Controllers and
Optics
Installation Included
Fluctuations in beam alignment, pump current, and temperature will all affect
the output frequency of a laser. Thorlabs’ Complete Stabilized Laser Systems
provide every component needed to control these variables and construct your
own Frequency Stabilized Laser.
Four versions of the kit are available, allowing the user to choose a Potassium
or Rubidium reference cell and either a Saturated Absorption (pages XXX XXX) or Dichroic Atomic Vapor (pages XXX - XXX) Spectroscopy System.
The Saturated Absorption version provides a highly sensitive signal by locking
directly to a narrow atomic transition of either Potassium or Rubidium. In
contrast, the Dichroic Atomic Vapor version offers a wider locking range and
the ability to tune the locking wavelength at the expense of losing the ability
to lock directly onto a known atomic transition wavelength.
Proportional and Integral Feedback Controller
IFC-B50 SPECIFICATIONS
-3 dB P-Gain Roll-Off Frequency
10 MHz
Low Frequency Gain
>80 dB
PI Corner Frequency
<1 MHz
Group Delay
<50 ns up to 12 MHz
Gain Flatness
>0.5 dB to ~8 MHz
Input Voltage Noise
Input Impedance
<10 nV/√Hz
50 Ω
IFC-B50
In order to stabilize the tunable laser kit, the signal created by the spectroscopy system is fed through the IdestaQE Proportional and
Integral Feedback Controller (see page XXX for details). The controller utilizes an “error” value given by the difference between a
measured process variable, produced by the spectroscopy systems, and a desired set point. Through a proportional and integral gain stage,
the controller will then generate a weighted output to minimize the “error.”
The IFC-B50 feedback controller is ideal for any application where low noise, flat phase, and high bandwidth are required. Its
proportional -3 dB bandwidth extends to 10 MHz, while the low-frequency gain is more than 80 dB. The group delay through the device
is also less than 50 ns up to a frequency of 12 MHz.
1810
www.thorlabs.com
Advanced
Applications
CHAPTERS
Complete Stabilized Laser Systems (Page 2 of 2)
Tunable Laser
Thorlabs’ Tunable Laser Kits (pages XXX - XXX) deliver
a highly stable free-space beam with linewidths of less than
130 kHz. The stock DC servo motor, which typically
drives the Littman Mirror, has been replaced with a PE4
Piezoelectric Actuator for quick response and precise
wavelength adjustment. The feedback loop generated by
the spectroscopy system, integral feedback controller, piezodriven wavelength selection mirror, and current driver
ensure a stable wavelength lock.
Also included with the TLK-780M tunable laser kit are the
sealed enclosure and heater. The TLK-E Enclosure allows
for gas purging in order to remove unwanted absorption
lines, which may interfere with the spectroscopic signals.
The heater provides the ability to control and stabilize the
temperature of the external cavity.
Optical Tweezers
Optical Delay Line
Supercontinuum
SECTIONS t
TLK-E
DAV Spectroscopy
TLK-L780M SPECIFICATIONS
MIN
TYPICAL
MAX
Center Wavelength
760 nm
770 nm
780 nm
Tuning Range (10 dB)
15 nm
30 nm
–
Peak Power
15 mW
50 mW
–
Wavelength Tuning Resolution
–
–
1 pm
Tuning Speed
–
–
40 nm/s
–
100 kHz
130 kHz
30 dB
45 dB
–
Linewidth
Side Mode Supression Ratio
Included Electronics
Included Optics and Mechanics
n
n
T-Cube Piezo Controller (TPZ001, See Page XXX)
n Laser Diode Temperature Controller (TED200C,
See Page XXX)
n Laser Diode Driver (LDC202C, See Page XXX)
n Two Heater Controllers (TC200, See Page XXX)
n All Necessary Cables, Connectors, etc.
n Two IdestaQE IFC-B50 Integral Feedback
Controllers (See Page XXX)
t
Frequency
Stabilization
Atomic Force
Microscope
n
n
n
n
n
SA Spectroscopy
Complete Stabilized
Laser Systems
MOT Application
PI Feedback
Controller
Free-Space Isolator (IO-3D-780-VLP, See Page XXX)
Anamorphic Prism Pair (PS875-B, See Page XXX)
Ø1/2" Mounted Multi-Order Half-Wave Plate
(WPMH05M-780, See Page XXX)
Cube-Mounted Polarizing Beamsplitter
(CM1-PBS252, See Page XXX)
FiberPort (PAF-X-11-B, See Page XXX)
All Necessary Mounts, etc.
ITEM #
FLK-DAV-TL-RB
$
$ 28,665.00
£
£ 20,638.80
ERMB
DESCRIPTION
E 24.938,60 ¥ 228,460.05 Complete Stabilized Laser System with DAV Spectroscopy, Rubidium
FLK-DAV-TL-K
$ 28,665.00
£ 20,638.80
E 24.938,60
¥ 228,460.05 Complete Stabilized Laser System with DAV Spectroscopy, Potassium
FLK-SAS-TL-RB
$ 28,665.00
£ 20,638.80
E 24.938,60
¥ 228,460.05
Complete Stabilized Laser System with SA Spectroscopy, Rubidium
FLK-SAS-TL-K
$ 28,665.00
£ 20,638.80
E 24.938,60
¥ 228,460.05
Complete Stabilized Laser System with SA Spectroscopy, Potassium
http://science.thorlabs.com
Multimedia is an increasingly effective tool at transferring knowledge from the
research lab it was created in to the minds of the people whose goals it will
inspire and enable. Thorlabs has started a site where researchers can present
their stories. Visit http://science.thorlabs.com to watch, learn, discuss, and
contribute. As always, we hope to hear from you.
Instrumentation Video:
The complete construction of a custom, real-time confocal scanning imaging
system for video-rate microscopy and microendoscopy is presented.
Research Method Video:
Quantitative measurements using optical tweezers require an accurate estimate
of the spring constant of the trap. Three methods for obtaining the constant are
demonstrated.
www.thorlabs.com
1811
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Optical Tweezers
Optical Delay Line
Supercontinuum
t SECTIONS
DAV Spectroscopy
SA Spectroscopy
Frequency Stabilized Laser Application:
Magneto-Optical Trap (Page 1 of 2)
Magneto-optical traps (MOTs) use a combination of lasers
and magnetic fields to localize and cool neutral atoms to
temperatures in the microkelvin regime. MOTs are essential
to ultra-cold atoms research and have enabled extensive studies
of Bose Einstein Condensates and Degenerate Fermi Gases.
To operate a MOT, two lasers need to be frequency locked
such that they are slightly detuned to the red of the atomic
transitions and stabilized to less than the natural transition
linewidth (~5 MHz). This locking offset can be achieved with
Thorlabs’ DAVS Stabilized Tunable Laser featured on pages
XXX - XXX.
Complete Stabilized
Laser Systems
MOT Application
PI Feedback
Controller
Have you
seen our...
New
Handheld
Power
and
Energy
Meter
Frequency Stabilized Lasers
The two lasers used in a MOT
provide both cooling and
confinement for the atoms. When
an atom absorbs a photon, its
momentum will increase in the
initial direction of the photon. To
ensure this absorption will slow the atom, the cooling
laser’s frequency is detuned to the red of atomic resonance
using the DAVS System. Under these conditions, only
atoms moving towards the laser source will be shifted into
resonance. Directionally dependent absorption of a photon will
thus slow the atom down. Additionally, a magnetic field gradient,
as described on the next page, is employed to create a positiondependent force that confines the atoms. The field and laser
polarizations (see image below) are chosen such that the
photons exert a restoring force on the atoms, which always
points toward the trap center.
F=4
5P3/2
F=3
F=2
F=1
σ+
I
See page XXX
σ-
σ
+
σ+
σ-
σ
-
1812
F=3
5S1/2
www.thorlabs.com
I
(a)
(b)
(c)
(d)
(e)
F=2
Six beams are necessary to provide confinement and cooling in three
dimensions. The diagram to the left shows these beams, three of
which are right circularly polarized (σ+) and three of which are left
circularly polarized (σ - ). For successful operation, two lasers have to
be stabilized close to the Rubidium D2 transitions. One laser, often
referred to as the “trap laser,” represented by (a) in the energy level
diagram above, provides the trapping forces. The second laser, known
as the “re-pump laser,” represented by (c) in the above diagram,
ensures that the Rubidium atoms do not accumulate in the F=2
ground state, which cannot be accessed by the trap laser.
Advanced
Applications
CHAPTERS
Frequency Stabilized Laser Application:
Magneto-Optical Trap (Page 2 of 2)
Magnetic Coils
n
n
n
n
n
Designed to Create 10 G/cm/A Field Gradient
Anti-Helmholtz Configuration
3 A @ 100% Duty Cycle with Passive Air Cooling
6 A with Limited Duty Cycle
Actual Field within 5% of Calculated Simulation (Simulation
Takes into Account Finite Coil Size)
To generate a linear magnetic field gradient for confinement, an
Anti-Helmholtz Coil System was designed and simulated. As shown
in the graphs below, a field gradient is produced within a 20 mm
range when measured along the axis created by the two coils (shown
in red). Centered between the coils, a uniform field gradient,
symmetric around the axis, with a 40 mm range in a perpendicular
plane (shown in blue) is also created.
t
Frequency
Stabilization
Atomic Force
Microscope
Optical Tweezers
Optical Delay Line
Supercontinuum
SECTIONS t
DAV Spectroscopy
SA Spectroscopy
Complete Stabilized
Laser Systems
MOT Application
PI Feedback
Controller
Magnetic Flux Density on Plane
Perpendicular to Axis
MOT Coils @ 3 A
Magnetic Flux Density on Axis
MOT Coils @ 3 A
80
Coaxial Field
Linear Fit
40
40
Field (G)
20
Field (G)
Perpendicular Field
Linear Fit
60
0
-20
20
0
-20
-40
-40
-60
-20
-10
0
Position (mm)
Vacuum
System
10
20
-40
-30
-20
-10
0
10
20
30
40
Position (mm)
A gas cell provides optical access for the six MOT beams. This chamber is evacuated
to a base pressure of 10-9 mbar by an ion pump. To dispense Rubidium into the
MOT chamber, small ovens containing Rubidium are situated inside the vacuum
system. By resistively heating these ovens using a current of typically 3 - 5 A, the
Rubidium will sublimate and diffuse inside the chamber volume.
Distinct solutions and individual components are
available. For more information or to place an order,
contact one of our Customer Support Specialists in
the USA at 973-300-3000 or visit www.thorlabs.com.
International contact details provided on the back cover.
Fluorescence of Rb atoms in the MOT cell, as
detected by a CCD camera.
www.thorlabs.com
1813
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Optical Tweezers
Optical Delay Line
Supercontinuum
t SECTIONS
10 MHz, Proportional and Integral Feedback Controller
Features
Adjustable Output Voltage Window Allows Seamless
Connection to a Variety of Different Instruments
n A Switchable Integrator Gain Limit to Easily Find the
Right Locking Point
n Error Signal Invert Switch
n Sweep Input
n
DAV Spectroscopy
SA Spectroscopy
Complete Stabilized
Laser Systems
MOT Application
PI Feedback
Controller
IFC-B50
IFC-50B
IdestaQE’s feedback controller features proportional (P) and
integral (I) gain stages. This purely analog device is designed for
ultra-low internal noise. The pick up and dielectric architectures
have been designed with a heavy emphasis on minimizing
transients. The proportional -3 dB bandwidth extends to 10 MHz,
while the low-frequency gain is more than 80 dB. The group delay
through the device is less than 50 ns up to a frequency of 12 MHz.
Gain settings can be changed completely independent of corner
frequencies. The IFC-B50 features an easy-to-control output
offset window, whose size and center can be changed orthogonally
between -10 V to 10 V. This allows the user to integrate the IFCB50 seamlessly into an application.
The IFC-B50 is the perfect instrument to frequency and intensity
stabilize lasers, for CEP/fceo stabilization, or any other kind of
feedback loop where low noise, flat phase, and high bandwidth are
required.
Feedback Control 101
A proportional–integral controller (PI controller) is a generic
control loop feedback mechanism widely used in control systems.
A PI controller uses an “error” value given by the difference
between a measured process variable and a desired setpoint and
attempts to minimize the error by adjusting the process control
inputs.
Component Block Diagram of an Elementary
Feedback Control
Error Signal
Reference
Σ
The proportional term in a feedback controller makes a change
to the output that is proportional to the current error value. The
proportional response can be adjusted by multiplying the error by
a constant proportional gain. A high proportional gain results in a
large change in the output for a given change in the error.
The contribution from the integral term is proportional to both
the magnitude of the error and the duration of the error. The
integral in a PI controller is the sum of the instantaneous error
over time and gives the accumulated offset that should have been
corrected previously. The accumulated error is then multiplied by
the integral gain and added to the controller output. The integral
term accelerates the movement of the process towards setpoint and
eliminates the residual steady-state error that occurs with a pure
proportional controller. The I response of the controller outweighs
the P response in frequency space below the PI corner frequency.
The output of the controller is the weighted sum of the
proportional and integral sections.
Applications
Laser Frequency Stabilization
Intensity Stabilization
n Laser Repetition Rate Stabilization
n CEP/fceo Stabilization
n
n
Perturbation
Specifications
Device to be Stabilized
IFC-B50
Actuator
Process
Sensor
The concept of a feedback loop is to control the dynamic behavior of a system. The sensed value
is subtracted from the reference to create the error signal, which is then processed by the feedback
controller and fed back into the system to compensate for perturbations.
ITEM #
IFC-B50
1814
www.thorlabs.com
$
$ 2,150.00
£
£ 1,548.00
-3 dB P-Gain Roll-Off Frequency:
10 MHz
n Low Frequency Gain: >80 dB
n PI Corner Frequency: <1 MHz
n Group Delay: <50 ns up to 12 MHz
n Gain Flatness: >0.5 dB to ~8 MHz
n Input Voltage Noise: <10 nV/√Hz
n Input Impedance: 50 Ω
n
Output
ERMB
E 1.870,50
¥ 17,135.50
DESCRIPTION
High-Bandwidth Integral Feedback Controller
Advanced
Applications
CHAPTERS
Have you seen our new...
Optical Spectrum Analyzers
Thorlabs’ Optical Spectrum
Analyzers are general-purpose
instruments that measure
optical power as a function
of wavelength. These OSA
instruments are versatile enough
to analyze broadband optical
signals as shown in Figures 1 and
2, the Fabry Perot modes of a gain
chip as shown on the computer
monitor to the right, or a longcoherent-length, single mode external
cavity laser as shown in Figure 3.
t
Frequency
Stabilization
Atomic Force
Microscope
Optical Tweezers
Optical Delay Line
Supercontinuum
SECTIONS t
DAV Spectroscopy
SA Spectroscopy
OSA201
Complete with Laptop Computer
Complete Stabilized
Laser Systems
MOT Application
PI Feedback
Controller
◆Wavelength Ranges Available
• OSA201: 350 - 1100 nm
• OSA203: 1000 - 2500 nm
◆Resolution
• Optical Spectrum Analyzer: 10 pm @ 633 nm
• Wavelength Meter Mode: 0.1 ppm
◆Update Rate as Fast as 2 Hz
◆Includes Laptop with Pre-Installed Software
Figure 1: Thorlabs’ LS2000B broadband optical
source, approximately 270 nm edge to edge, with
approximately 5 µW of power delivered to the input
of the FT-OSA. The fine structure visible across
the spectrum is due to Fabry Perot modes of the
semiconductor element, and the structure on the right
are the expected water absorption lines that occur in
the 1350 to 1400 nm range.
Figure 2: Using the analysis features of the Optical Spectrum
Analyzer, the absorption lines can be viewed by subtracting
off the overall envelope of the source. An additional function
allows automatic labeling of any valley (or peak) that crosses
a user-defined threshold.
Figure 3: 1550 nm gain chip in an external cavity laser.
The software is set up to display the spectrum and the
optical power. The Wavelength Meter Mode window is also
activated. Long-term wavelength accuracy is ensured by the
the stabilized HeNe Reference Laser, incorporated inside of
the system.
For more details, see pages XXX - XXX
www.thorlabs.com
1815
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Atomic Force Microscope Teaching Kit (Page 1 of 6)
Features
n
Modular Advanced Teaching Setup
Images Nanometer-Sized Height Features
n Contact Mode Measurement
n Interdigital Cantilever Probes
n 20 µm x 20 µm Scan Range (Longer
Range Available Upon Request)
n Measurement of Young’s Modulus and
Boltzmann’s Constant
Optical Tweezers
n
Optical Delay Line
Supercontinuum
t SECTIONS
Atomic Force
Microscope
Thorlabs’ Atomic Force Microscope (TKAFM) Kit
was designed in collaboration with Steven Nagle and
Prof. Scott Manalis at MIT’s biological engineering group for
use in undergraduate teaching labs. It allows students to learn about
the measurement principles and fundamental physics important to highresolution scanning probe microscopy. Besides imaging, users can analyze noise
sources, probe stiffness, and Young’s modulus of samples and replicate the experiment
of measuring the Boltzmann constant as described by M. Shusteff et al.1
The System Includes Everything Needed to Get Started
n
Set of Cantilevers with Various
Geometries
n Calibration Sample with
25 nm Steps
n Data Acquisition Hardware
n
CMOS Camera and Light Source
to Facilitate Sample Alignment
n Control Software
(A Computer with USB Ports is
Required to Operate the AFM Kit.)
Thorlabs’ AFM is a modular system
that can be adapted and extended to
meet a variety of needs in teaching
and basic metrology applications. The
three-axis flexure stage (MAX311D)
that is used for sample positioning
is the same one as used in Thorlabs’
Optical Trapping kit, allowing multiple
educational setups to be built from the
same components.
Have you
seen our...
Cage
Systems
AFM Image of ~ 1 µm Polystyrene Beads
Image Area: 8 µm x 8 µm
AFM 3D Plot of AppNano Silicon Step Height
Reference
Image Area: 10 µm x 10 µm
Feature Height: 83 nm with 3 µm Pitch
AFM Image of the Calibration Sample
Image Area: 20 µm x 20 µm
Feature Height: 25 nm
See page XXX
To discuss your specific application requirements, please contact your local Tech Support office or email [email protected].
1M. Shusteff, T. P. Burg, and S.R. Manalis, “Measuring Boltzmann’s constant with a low-cost atomic force microscope: an undergraduate experiment.” Am. J. Phys., 74, 873-79 (2006).
1816
www.thorlabs.com
Advanced
Applications
CHAPTERS
Atomic Force Microscope Teaching Kit (Page 2 of 6)
t
Frequency
Stabilization
Atomic Force
Microscope
AFMs allow sub-nanometer scale imaging of surfaces
by scanning a nanometer scale cantilever tip across the
sample and recording the vertical movement of the
tip as it moves across the specimen. Typical AFMs
direct a laser beam onto the cantilever tip assembly
and measure the displacement of the reflection
using a segmented photodiode. Alignment and
noise sensitivity can be a challenge in such a setup;
this challenge is simplified by using an interdigital
cantilever tip assembly.
Optical Tweezers
Optical Delay Line
Supercontinuum
SECTIONS t
Atomic Force
Microscope
The Thorlabs AFM kit uses a different kind of probe
system that includes interdigital (ID) fingers on the
cantilever. Half of these fingers are fixed, while the
other half move with the cantilever. The two groups
of fingers form a diffraction grating, which is optically
interrogated via the resulting diffraction effects.
Electron micrograph of a cantilever tip. Scanning the sub-nanometer-sized tip across a sample
allows one to obtain information on length scales much smaller than the diffraction limits of
optical microscopy.
To measure the deflection of the cantilever, a visible (635 nm) class 1 laser beam is focused
on the finger structure. The beam gets diffracted into several modes, which are collected by
the focusing lens.
Laser Diode with
Collimating Optic
The modes are guided by a beamsplitting cube towards an amplified photodetector. An iris
diaphragm ensures that only the one diffraction mode is recorded by the detector.
Detector
The power recorded in the mode is a measure of the cantilever’s displacement. For example,
the zero-order mode (i.e., the reflected beam) has its maximum intensity when there is no
cantilever displacement. In this case the path difference between light reflected from the
fixed and moving fingers is zero, and the outgoing light interferes constructively.
Beamsplitter Cube
Iris
Focusing Lens
LED Sample Illuminator
When the cantilever is displaced by a quarter of a wavelength (~150 nm), the power in
the zero-order mode is minimized. Light reflected by the moving fingers has a l/2 path
difference with respect to light coming off the fixed reference fingers, leading to destructive
interference. The separation between the fingers at this point is l/4, since the light will need
to travel this distance two times.
The displacement is therefore determined by measuring the optical power of the reflected
mode. Due to this, sensitivity to mechanical noise is reduced and laser pointing noise will
not be an issue.
ID Cantilever
Sample
Quantum Dots
180
2.5
160
Position (µm)
140
120
2
100
80
60
1.5
40
20
1
2
3
4
5
6
7
Position (µm)
8
9
0
AFM image of 1:5 solution of PbS quantum dots in chloroform spun
on Si substrate.
Electron micrograph of an ID cantilever. The
central beam houses the tip and moves with sample
height, while the outer beams are stationary.
Power in the diffraction modes changes with cantilever
position. The white and gray boxes represent the fingers
on the cantilever probe. The two groups of fingers form a
diffraction grating.
www.thorlabs.com
1817
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Optical Tweezers
Optical Delay Line
Supercontinuum
t SECTIONS
Atomic Force
Microscope
Atomic Force Microscope Teaching Kit (Page 3 of 6)
Force Measurement Technique
To allow quantitative measurements and optimize
image quality, the setup needs to be calibrated.
During calibration, the sample is oscillated
vertically using the stage piezo while the detector
voltage is plotted as a function of the piezo
drive voltage. With the tip in contact with the
sample surface, the set of fingers connected to the
cantilever will move up and down accordingly.
The reflection from the moving fingers will
interfere with the one from the fixed fingers,
resulting in a sinusoidal intensity variation. A
change of the detector voltage (I) from minimum
to maximum therefore corresponds to a relative
movement ∆z of the fingers of a quarter
wavelength:
I µ sin2 [
2π
λ
Δz]
The highest sensitivity is achieved if the system is operating around the point with the highest slope on the calibration curve.
Residual strain in the silicon nitride from which the cantilevers are fabricated results in a relative planar displacement of the two
finger sets, even if the cantilever is not in contact. Since this displacement varies slightly over the area of the grating structure,
typically by a few hundred nanometers, the detector output level can be adjusted along the calibration curve by moving the incident
laser spot side to side on the diffraction grating. The image above shows the detector voltage vs. stage piezo voltage. The red (green)
curve is acquired while the sample is moved towards (away from) the cantilever. Due to adhesive forces, the stage usually needs to be
moved significantly farther away before the tip will be released from the surface.
In the bottom two frames, the detector signal as a function of time and the corresponding histogram are shown.
Included with the TKAFM kit is an application software package that operates all controls needed to obtain 2D images. Operation
includes piezo motion control for a scan area up to 20 µm x 20 µm (larger area available upon request). Resolution and image contrast
may be adjusted in the 20 µm x 20 µm area by dividing the image canvas into as few as 10 by 10 pixel points, or as many as 500 by
500 pixel points. The developed TKAFM software integrates National Instruments’ data acquisition software and Thorlabs’ apt™
(advanced positioning technology) software under NI’s LabWindows™/CVI to control and operate the TKAFM.
AFM main control panel
shown capturing an image of
bond pads in a phase-locked
loop integrated circuit.
1818
www.thorlabs.com
Advanced
Applications
CHAPTERS
Atomic Force Microscope Teaching Kit (Page 4 of 6)
In addition to many other applications, Thorlabs’ TKAFM kit can be used to measure the Boltzmann constant by observing thermal
motion of the cantilever. The optical detection scheme described previously is sensitive enough to detect and quantify these thermal
fluctuations of the cantilever position. The magnitude of this motion is used to deduce the Boltzmann constant.
Modeling the cantilever as a one-dimensional harmonic oscillator, the total energy of the system E can be expressed as the sum of kinetic
and potential energies:
1
1
2
2
1
1 〈
2 〈
2
Optical Tweezers
Optical Delay Line
Supercontinuum
1
1
2
2
SECTIONS t
Here, m is the mass, k the spring constant, and z the deflection of the cantilever. By the equipartition theorem, the average potential
energy of the cantilever due to thermal fluctuations is given by
1
1
2
2
t
Frequency
Stabilization
Atomic Force
Microscope
Atomic Force
Microscope
〉
〉
where T is the absolute temperature and <z 2> is the mean-square displacement.
Letting the cantilever oscillate freely (i.e., without contact to a sample), the mean-square
displacement can be directly obtained from
1
|
time-domain data recorded by a photodetector (refer
to| the Force Measurement
1 Technique presentation on the previous page for details).
|
|
However, this method generally yields poor results, as the data will include 1/f noise due to thermal drifts, enhanced oscillations at
the resonant frequency of the cantilever, and other non-thermal noise sources, depending on the environment (e.g., 60 Hz noise from
ambient lighting or 10 1- 40 kHz noise
1 from switching power supplies).
2
|
|
1
where Q is the quality factor of the oscillation, and ω0 is the
resonant frequency. Typical values for the ID cantilevers are
ω0 = 1.1 kHz and Q = 40.
100
Fitted Model
Detector Background
Thermal Noise
Cantilever Deflection (pm/ Hz)
2
Analysis in the frequency domain allows for better results. The
TKAFM software package performs a fast Fourier transform (FFT)
on the time domain data to obtain the signal’s power spectral
1
density (PSD). Such a1plot is shown
〈 to
〉 the right. By fitting the
2 cantilever
2 to the data, the Boltzmann
transfer function of the
constant can be determined. The transfer function is given by
10
1
100
1000
Frequency (Hz)
The Boltzmann constant obtained by fitting
the data shown above is 1.69 x 10-23 J/K.
Typically, one obtains a result matching the
accepted value for kB (1.38 x 10-23 J/K) within a
factor of two. The largest source of error in the
analysis is the spring constant k, which has to
be calculated from the cantilever’s material and
geometrical properties. The cantilever used for
the thermal noise experiment is shown to the
left. Its symmetric structure helps to reduce any
common noise.
www.thorlabs.com
1819
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Atomic Force Microscope Teaching Kit (Page 5 of 6)
Young’s Modulus Experiment
Optical Tweezers
Another educational experiment that can be conducted using the Thorlabs AFM Kit is to measure the elasticity (Young’s modulus) of
microscopic samples, as demonstrated by Touhami et al.2
Optical Delay Line
To perform the measurement, a hard surface (e.g., a Silicon Nitride wafer or steel plate) is used as a reference. A plot of detector signal
versus stage displacement is recorded as the AFM tip comes in contact
with the surface, which causes the cantilever to be displaced.
Supercontinuum
t SECTIONS
Atomic Force
Microscope
After recording this calibration curve, the same procedure is followed
for the actual sample, such as a biological cell. When the cantilever
comes into contact with a soft biological sample, the elasticity of the
cell will retard the displacement of the cantilever. This retardation in
displacement is a result of the atomic forces acting between the cantilever
tip and the relatively soft biological sample that readily compresses as the
cantilever tip approaches. The effect is illustrated in the plot to the right
by the black and red curves, which show this retardation when using
a steel and then glass plate, respectively, as illustrative samples. When
deforming the glass plate, the sample needs to be moved farther than for
a steel plate to achieve the same cantilever displacement.
The elasticity of the sample can then be quantified by analyzing the
difference in the period of the curve. Assuming a conical shape of the
AFM tip, the cantilever displacement z is related to Young’s modulus of
the sample E by
Z
2E
(1
)
Here, k is the known spring constant of the cantilever, α is the
cone angle of the tip, v is the substrate’s Poisson ratio, and δ is the
deformation of the sample surface. Since the probes delivered with the
system have a pyramidal shape, the absolute values measured will deviate
from values in the literature.
2A.
Force Curves: a sample of steel (black curve) and glass (red curve) is
brought in contact with the cantilever tip while the detector voltage
is measured. The period of the signal while in contact depends on the
elasticity of the sample.
Touhami, B. Nysten, and Y. F. Dufrene. "Nanoscale Mapping of the Elasticity of Microbial Cells by Atomic Force Microscopy" Langmuir 19 (11), 4539-43 (2003).
Fiber Interferometric Option
The modularity of the TKAFM allows for simple conversion to alternative measurement
techniques. One technique popular in scanning probe microscopes utilizes optical fiber.
In this case, the end surface of a fiber is brought into close proximity
to the cantilever. At the fiber-air interface, about 4% of the light is
reflected back. This light will interfere with the light reflected
back into the fiber from the cantilever.
By converting the TKAFM so it utilizes optical
fiber, standard cantilevers can be used, although
not necessary. Similarly to the interdigital
cantilevers, as the probe is scanned over the
sample, the vertical movement is detected
interferometrically. The height
change determines the phase shift
between light reflected at the fiber end
face and the light reflected off the cantilever.
A cage segment with the laser diode, beamsplitter cube, and detector
is mounted on the optical table. The focusing lens, usually placed above the ID
cantilever, is replaced by a FiberPort that couples the laser into a segment of single mode fiber.
The other end of the fiber is cleaved and mounted above the cantilever using a K6X kinematic mount (see page XXX).
This conversion is also particularly well suited for advanced teaching labs, as it allows users to get familiar with fiber handling
techniques, such as stripping and cleaving fibers. If you are interested in this option, please contact us at [email protected].
1820
www.thorlabs.com
Advanced
Applications
CHAPTERS
Atomic Force Microscope Teaching Kit (Page 6 of 6)
t
Frequency
Stabilization
Atomic Force
Microscope
Interdigital Cantilevers
Thorlabs’ replacement interdigital cantilevers are silicon nitride
cantilevers with a silicon tip. The grating structure, which is built
into the cantilever, allows measurement of displacement between
the cantilever tip and the sample via interference rather than
displacement, which reduces sensitivity to mechanical and laser
pointing noise. For an analysis of the properties of interdigital
cantilevers, please refer to Yaralioglu, et al., “Analysis and design of
an interdigital cantilever as a displacement sensor” J. Appl. Phys.
83, 7405 (1998.)
Optical Tweezers
Optical Delay Line
Supercontinuum
SECTIONS t
Atomic Force
Microscope
Due to the fact that AFMs utilizing these cantilevers operate via
interference, rather than direct reflection, effects such as thermal
noise are reduced.
Offered in sets of 10, each wafer supports 4 cantilevers with spring
constants ranging from 0.03 – 0.1 N/m and resonant frequencies
from 6 – 16 kHz, as seen in the chart below. This variety facilitates
multiple applications and experiments.­­­­
The largest cantilever facilitates the cleanest imaging over a range of feature heights, while the shortest pair of cantilevers are best suited for
Young’s Modulus Measurements (see opposite page). A cantilever containing only one set of fingers has been included for vibrational noise
measurements. By using a pair of identical cantilevers that support the fingers, common drift effects and unwanted resonances are reduced.
0 µm
CANTILEVER SPECIFICATIONS
Long Imaging
Thermal Noise
Modulus Measurement
Modulus Measurement
Length (±10 µm)
375 µm
350 µm
300 µm
225 µm
Width (±2 µm)
50 µm
60 µm
60 µm
60 µm
Resonance Frequency*
6 kHz
7 kHz
9 kHz
16 kHz
0.014 - 0.022 N/m
0.028 - 0.043 N/m
0.067 - 0.100 N/m
0.014 - 0.022 N/m
Force Constant*
50 µm
Application
Schematic Drawing
50 µm
*Calculated Using Design Parameters
$
$ 9,990.00
£
£ 7,192.80

TKAFM/M
$ 9,990.00
£ 7,192.80

TKAFM-CTL
CALL CALL
ERMB DESCRIPTION
8.691,30
¥ 79,620.30
AFM Kit with Interdigital Cantilever
8.691,30
¥ 79,620.30 AFM Kit with Interdigital Cantilever, Metric
CALL
CALL
Have you seen our...
Cantilever Probes, Set of 10
50 µm
ITEM #
TKAFM
ScienceDesk™
Workstations
Thorlabs’ ScienceDesk™ is a modular workstation with a versatile selection
of frames and optional accessories that allows you to build a customized,
ergonomic work space for your specific application. New to the line is an
active-air frame and 5' x 6' (1500 mm x 1800 mm) breadboard designed to
accommodate a multiphoton imaging setup.
◆Rigid, Passive, and
Active-Air Welded Steel
Frames
◆Stainless Steel Tabletop
SDA150180 Frame
and PerfomancePlus Breadboard
shown with Thorlabs’ MPM200
Multiphoton Microscopy System
(With or Without
Holes; Nonmagnetic
Options also Available)
◆Modular System of
Accessories
For more details, see page XXX
www.thorlabs.com
1821
Advanced
Applications
t CHAPTERS
Optical Tweezer Kit (Page 1 of 4)
Frequency
Stabilization
Atomic Force
Microscope
Optical Tweezers
Optical Delay Line
Supercontinuum
t SECTIONS
Optical Tweezers
Accessories
Optical Tweezers, or traps as they are often called, have become
an important tool in a wide range of fields such as bioengineering,
material science, and physics due to their ability to hold and
manipulate micron-sized particles and to measure forces in the
pN range.
The OTKB Optical Tweezer Kit bundles a carefully selected
set of components to construct an optical tweezer system. The
modular nature of the system makes it attractive for advanced
teaching and research laboratories as changes in users’ applications
can easily be accommodated. Since the optical trap system is built
using mainly standard Thorlabs components, it is easy to modify
or upgrade the system using other standard Thorlabs parts. The
kit is shipped in several preassembled segments. When received,
setup consists of connecting the segments and doing the necessary
laser alignment.
While the OTKB kit includes all components required to build
the optical trap, the OTKBFM Force Measurement Module can
be added to allow quantitative measurements (see page XXX).
S. Wasserman, D. Appleyard, and M. Lang at the Department of
Biological Engineering, MIT published an article [Optical trapping
for undergraduates, Am. J. Phys. 75 (1), January 2007] on an
optical trapping system that they built for use in teaching labs.
Features
n
Complete Optical Tweezer Kit
Inverted Light Microscope Design
n 975 nm DFB Trap Laser, 330 mW Power (Max)
n 5 W, 1064 nm Fiber Laser Available Upon Request
n Nikon 100X Oil Immersion Objective
n 3-Axis Sample Positioning Stage
n CCD Camera for Video Imaging
n Position-Sensing Detector Module Available
n
Thorlabs, in collaboration with the aforementioned individuals,
has developed this kit so that others may build an optical trap with
similar capabilities as the system published in the American Journal
of Physics. Some examples of additional modules that have been
added to the system include multiple trap creation, beam steering,
fluorescence spectroscopy, Raman spectroscopy, and two-photon
excitation. If you have an application that requires a particular
modification, please contact us at [email protected].
Optical Tweezer Setup
LEDWE-10
2.6 mW White LED
OTKBFM
Force Measurement
Module
TCH002, TPZ001,
TSG001, TQD001
Controllers for
Stage and Quadrant
Position Detector
MAX3SLH
Microscopy Slide Holder
Condenser
MAX311D
NanoMax™ Stage
Laser Diode and
Temperature Controller
Oil
Immersion
Objective
DCU224
CCD Camera
Beam
Expander
PL980P330J
Trapping Laser
PAF-X-7-B
FiberPort
1822
www.thorlabs.com
LM14S2
Butterfly Laser Diode
Mount
Advanced
Applications
CHAPTERS
Optical Tweezer Kit (Page 2 of 4)
OPTICAL TWEEZER SPECIFICATIONS
Tweezer Resolution
~0.05 pN
Spot Size
≥0.6 µm
Depth of Focus
Optical Tweezers
~1 µm
Power at Optical Trap
~42% of Fiber Output
­Power at Fiber Output*
330 mW (Max)
Input Beam Diameter
Optical Delay Line
Supercontinuum
Ø4.74 mm
SECTIONS t
OBJECTIVE SPECIFICATIONS
Type
Nikon 100X Immersion Objective
Numerical Aperture
Optical Tweezers
1.25
Input Aperture
Ø5 mm
Working Distance
0.23 mm
Transmission
Accessories
380 - 1100 nm
Recommended Cover Glass Thickness
System Description
t
Frequency
Stabilization
Atomic Force
Microscope
0.17 mm
CONDENSER LENS SPECIFICATIONS
Type
The trapping source in the Optical Tweezer Kit is
Numerical Aperture
a temperature-stabilized 330 mW (max) SM fiberWorking Distance
pigtailed laser diode with a central wavelength of
Transmission
975 nm. The output of the laser is collimated using
*5 W laser at 1064 nm available upon request.
a FiberPort, which allows the aspheric collimation
lens to be precisely positioned along 5 axes (X, Y, Z,
Pitch, and Yaw). For polarization-sensitive applications, the keyway on
White Light
the FiberPort can be rotated about the optical axis so that the orientation
Source
of a linearly polarized collimated beam can be set. A 2.5X Galilean beam
expander is used to fill the aperture of the focusing objective. The dichroic
mirror reflects 975 nm light (trapping source) into the vertical path of the
setup where a 100X oil immersion Nikon objective lens is used to focus the
Position Sensing
Detector
trapping laser beam down to a spot size greater than 0.6 µm.
The microscope slide is positioned using a 3-axis (X, Y, and Z) translation
stage that provides 4 mm of manual travel in combination with 20 µm
of piezo actuation and a resolution of 20 nm. Using the internal strain
gauges for positional feedback, 5 nm resolution can be achieved. The stage
is mounted on a single-axis, long-travel translation stage, which allows
scanning over a range of 2" (50 mm). The complete sample holder setup
is placed on a translating breadboard, which facilitates loading/unloading
of samples. The trapping laser is collimated by the condenser and reflected
down the optional OTKBFM Force Measurement Module (see page XXX).
If the OTKBFM is not being used, the laser is blocked using an SM1CP2
end cap.
A single emitter white light LED (LED driver included) is used to
illuminate the sample. The light coming from the LED will pass through
the dichroic mirrors and is imaged on a 1280 x 1024 CCD camera. An
additional laser (e.g., to generate fluorescence) can easily be coupled into
the setup by adding another dichroic mirror as shown on next page.
Lens
0.25
7 mm
380 - 1100 nm
EC
LD & TEC
ler
Controller
Dichroic
Mirror
Condenser
Lens
Sample
Holder
Butterfly
Mount
Fiber
FiberPort
Objective
Lens
Sample
XYZ Sa
am e Stage
Mirror
Software
The Optical Tweezer Kit includes the powerful apt™ software package for
full computer control of the 3-axis piezo-driven sample positioning stage
and to read out the quadrant detector signal. For faster data acquisition, a
DAQ card is needed. It also includes software for the CCD camera for video
imaging. The ActiveX®-based software modules can be used to develop
custom applications (e.g., using LabWindows CVI, Visual C++, Matlab,
HPVEE). A procedure for this data analysis can be found in “Calibration of
optical tweezers with positional detection in the back-focal-plane, Review of
Scientific Instruments 77, 103101, 2006.”
Nikon 10X Air Condenser
Lenss
CCD Im
Imaging
Detec
cttor
Detector
Beam
Expander Dichroic
Mirror
Assembly and Testing
The Optical Tweezer Kit is shipped partially assembled with an easyto-follow step-by-step assembly instruction manual. For customers who
prefer to have the system installed, please contact technical support at
[email protected] for a quotation. For testing, we recommend
the OTKBTK Sample Preparation Kit (page XXX), which provides users
with everything necessary to prepare a sample of 1 µm fused silica beads.
www.thorlabs.com
1823
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Optical Tweezers
Optical Delay Line
Supercontinuum
t SECTIONS
Optical Tweezers
Accessories
Optical Tweezer Kit (Page 3 of 4)
Optical Tweezer Theory Basics
The forces that enable particle trapping using light are created
by momentum transfer from laser light interacting with particles.
With a Gaussian input beam and a dielectric particle, reflection
and refraction are the two mechanisms that can be used to
describe the process. Usually the sum of those forces is divided
into two components: the gradient force component, which
draws an object into the center of the beam, and a scattering
force component, which pushes the object along the direction
of light propagation. Unless there is a steep gradient of light
intensity, the scattering force will push the object out of the
trap. This condition is met by using a high-numerical-aperture
objective that produces a gradient force large enough to balance
the scattering force, and as such, the trap location will always be
above the focal point of the objective.
The size of this focal point will always be greater than the limit
imposed by diffraction theory according to the equation:
≥
1 .22
In most situations, however, the particle sizes are comparable
to the wavelength, like in our case where we have demonstrated
1 - 2 µm particle trapping with a 0.975 µm wavelength. The
complete treatment in this case becomes a little complex but has
been described in several publications.* However, there are a few
important things to note about the strength of the optical trap;
it increases with the power of the light beam, it increases with a
decrease in the size of the focused spot, and the trap is weakest in
the direction of beam propagation. This can be summarized in
the expression for the maximum force that can be exerted by the
trap in a medium with refractive index n:
1
Here, Q is a scaling constant that depends on the particle size
and refractive index difference between particle and medium, P is
the incident power, and c is the speed of light in vacuum.
Here, l is the wavelength, η is the refractive index of the
medium, and NA is the numerical aperture of the objective.
*e.g., “Optical trapping,” Keir C. Neuman and Steven M. Block, Rev. Sci. Instrum. 75, 2787 (2004)
Optical Tweezer Application Module: Fluorescence Spectroscopy
Objective
Tweezers
Laser
By combining Fluorescence Spectroscopy with optical tweezers, researchers can visualize, manipulate, and
rapidly characterize the properties of various samples including single molecules. Such a technique can be used
to detect the arrival of a single molecule into a small volume of space, detect the conformational changes of
a single molecule, study elastic properties of single DNA, and demarcate different parts of a larger molecular
complex and measure the response of each to an applied force.
The application example presented
here shows a fluorescence module
Excitation
added to the Thorlabs optical tweezer
Incident
Radiation
system. As a sample, a diluted solution
Fluorescence
Excitation
(Emission)
of 1.0 µm uniform dyed polystyrene
Filter
beads (Bangs Lab FS04F/9066) with
Emission
Filter
an excitation wavelength of 480 nm
and an emission wavelength of
CCD Camera
520 nm were used. The excitation
(or other detection system)
light is selected from Thorlabs’ HPLS
high-power plasma source in combination with the MF475-35 excitation
filter, which has a transmission of more than 85% in the 470 - 490 nm range.
The light is then coupled into the tweezer system using a MD499 dichroic
mirror, which reflects light in the 470 - 490 nm range and transmits light in
the 508 - 675 nm range. As with any standard epi-fluorescence technique, the
fluorescence light, which is emitted by the sample, will be collected by the
objective together with any reflected excitation light, giving a better signal-tonoise ratio as with a transmissive detection scheme. This signal then goes back
through the dichroics and an MF530-43 emission filter with a 530 nm center
wavelength and a 43 nm bandwidth and is detected by the CCD camera.
Fluorescence
Source Input
Dichroic
Mirrors
Please see page XXX for different fluorescence filters and combinations that will
be suitable for your application.
1824
Theoretical calculations of the forces exerted by an optical trap on a
trapped particle usually fall into one of two regimes. If the trapping
wavelength is greater than the size of the particle, the Rayleigh
scattering treatment is used, and when the wavelength is less than the
particle diameter, the Mie scattering treatment is considered.
www.thorlabs.com
CCD Camera
Dichroic
Filter Cube
OTKB
Advanced
Applications
CHAPTERS
Optical Tweezer Kit (Page 4 of 4)
t
Frequency
Stabilization
Atomic Force
Microscope
Optical Tweezer Application Module: Galvonic Steering
Optical Tweezers
Optical Delay Line
Supercontinuum
SECTIONS t
Optical Tweezers
Accessories
Automated trap positioning capability can be added to the optical tweezer kit by
integrating Thorlabs’ 2D galvo mirror GVS002 (see pages XXX - XXX). The
galvo mirror replaces the turning mirror at the fiber input and is positioned
in a plane conjugate to the back aperture of the objective. For the Keplerian
configuration, rotations introduced by the galvo mirrors at a distance x
from the first lens will be recreated at a distance y from the second lens
according to equation
y=
(
⁄
− (x−
)
)
y = lenses.
− ( xThe
− )
where f1 and f2 are the focal lengths of the two relay
magnitude of this rotation at location y is ( ⁄ ) times the
magnitude at location x.
The example shown in the picture above is constructed with achromatic doublet lenses
(AC254-060-B and AC254-150-B; see page XXX). The first achromatic doublet is
mounted into an adjustable lens tube (SM1V10 featured on page XXX) and is positioned
one focal length away from the center of the scanning mirrors. The multiplying factor to
rotations created at the galvo mirrors position is 0.4.
Drive voltages are applied to the galvo mirror controller boards via a DAQ card, allowing
the user to position the trap while the sample stage remains stationary. Due to the
optical path length between the galvo mirror and the back aperture of the objective, only
small angle adjustments are necessary, which means that the galvo mirror can operate
at its maximum bandwidth of 1 kHz. By moving the beam back and forth between two
positions with an appropriate dwell time at each position, it is possible to create two stable
traps from a single laser beam. The images below display an example of two beads, 1 µm
in diameter, that are simultaneously trapped by scanning the galvo mirrors at 200 Hz. The
separation of the beads is about 6 µm.
For more details regarding
customization or modifications
to the Optical Tweezer Kit,
please contact the Advanced
Applications Group at
[email protected]
Simultaneously
Trapped 1 µm Beads
Our optical tweezer samples preparation kit is recommended for customers new to the field of optical
tweezers. See page XXX for ordering details.
ITEM #
OTKB
METRIC ITEM #
$
£
ERMB
OTKB/M
$ 17,390.00 £12,520.80 E 15.129,30 ¥ 138,598.30
DESCRIPTION
Optical Tweezer Kit – Base Module
www.thorlabs.com
1825
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Optical Trapping Force Measurement Module
Features
Optical Tweezers
Position Calibration
Stiffness Calibration
n Optical Trapping Force Measurement
n Simple Integration into OTKB Optical Tweezer Kit
n Quadrant Position Detector and Strain Gauge Controller
Software Included
n
n
Optical Delay Line
Supercontinuum
t SECTIONS
Optical Tweezers
Accessories
The power spectrum below exhibits measurement
data from the XDIFF signal of the Quadrant
Detector Reader for 200 ms. The drive current was
around 300 mA, and the signal was acquired using a
DAQ card at a sampling frequency of 100 kHz. The
power spectrum was calculated and plotted against
the log of the frequency. A Lorentzian fit (not shown)
will enable the determination of the corner frequency
from which the trap stiffness can be calculated.
10-5
10-6
Thorlabs’ OTKBFM Force Measurement Module offers the
ability to calibrate the OTKB Optical Tweezer Kit for position
detection and measurement of small forces. The module contains
the hardware needed to calibrate the trap using positional
detection in the back focal plane of the condenser. By placing
the Quadrant Position Detector (QPD) in a plane conjugate to
the back focal plane of the condenser, the signal generated by
the QPD is sensitive to the relative displacement of the trapped
particle from the laser beam axis. As a result, the output of the
detector can be used to calibrate the position, stiffness, and force
of the optical trap. The detector is connected to the cage cube
above the condenser. A TQD001 T-Cube Quadrant Detector
Reader and two TSG001 T-Cube Strain Gauge Readers are the
main components included in this module. For high-bandwidth
measurements, the QPD signal can be read out from the
controller cube directly via a DAQ card (not included).
Power Spectrum (a.u.)
10-7
10-8
10-9
10-10
10-11
10-12
10-13
10-14
101
102
103
104
The OTKBFM includes the powerful apt™ software
package to read out the quadrant detector signal; data
analysis and calculation routines are to be written by
the user. The ActiveX®-based software modules can
be used to develop custom applications (e.g., using
LabWindows CVI, Visual C++, Matlab, HPVEE).
The example MATLAB-based graphical user interface
described below is available for download from our web
presentation at www.thorlabs.com/OpticalTweezers.
Frequency (Hz)
The MATLAB-based graphical user interface (GUI), shown to the
left, was developed through a collaboration with Massachusetts
Institute of Technology and allows calibration of Thorlabs’
Optical Tweezer system. Among the features developed with this
software is a position calibration capabilitiy along the X and Y
axes, stiffness calibration using the power spectral density, Stokes
Drag and Equipartition methods. It also includes an example
Biological Assay - DNA tether. This involves stretching a piece
of DNA that is attached to a coverslip on one side and a bead on
the other side, thereby allowing the determination of the DNA
tether length. For more information about the methods referred
to above, please see Appleyard et al. “Optical Trapping for
Undergraduates” Am. J. Phys. 75 (1) January 2007.
ITEM #
OTKBFM
1826
www.thorlabs.com
$
$2,800.00
£
£2,016.00
ERMB
E 2.436,00
¥ 22,316.00
DESCRIPTION
Force Measurement Module
Updated Specs
1-29-14 - LF
Advanced
Applications
CHAPTERS
Optical Tweezer Sample Preparation Kit
The OTKBTK Sample Preparation Kit is designed to allow users to quickly
prepare a sample with 1 µm fused silica beads and test any optical tweezer
system. We usually recommend purchasing this with our optical tweezer system.
Optical Tweezers
Kit Contents
n
n
n
n
n
OTKBTK
n
n
ITEM #
OTKBTK
$
$ 118.88
£
£ 85.59
ERMB
E 103,43
¥ 947.47
t
Frequency
Stabilization
Atomic Force
Microscope
Non-Drying Immersion Oil for Microscopy,
Cargille Type B
Non-Functionalized Fused Silica Beads in
Water, Ø1 µm, <0.5 g/mL
Mini Pipette with a 50 µL Volume
Two Plastic Slides with Built-In Channel,
400 µm Height, 100 µL Volume
5 Microscope Slides with Reaction Walls,
Ø10 mm, 20 µm Deep
100 Pieces of 18 mm x 18 mm Cover Glass,
No. 1 Thickness
Dropper for Immersion Oil
Optical Delay Line
Supercontinuum
SECTIONS t
Optical Tweezers
Accessories
DESCRIPTION
Sample Preparation Kit for Optical Trapping
Microscopy Slide Holder
Features
Accommodates Glass Slides of Variable Width
and a Length ≥ 44.0 mm (1.73")
n Compatible Petri Dish Diameters:
37 - 41.4 mm (1.46" - 1.63")
n Spring Clips Hold Sample Firmly in Place
n Mounting Hole Compatibility
• MAX Series Stages (See Pages XXX - XXX)
• Any Stage with 1/4"-20 (M6) Taps on
2" Centers
n Dimensions: 101.6 mm x 68.6 mm x 12.7 mm
(4" x 2.7" x 0.5")
n
MAX3SLH
The MAX3SLH Microscopy Slide Holder
offers your motion control stages the ability
to mount petri dishes and glass slides for integration
into personalized microscopy setups like the optical
tweezers. Two sets of mounting holes allow versatility:
one set of four 6-32 (M3) counterbores compatible with our
3-axis MAX Series stages (see pages XXX - XXX) and a set of
1/4"-20 (M6) slots with 2" separation for mounting to most other
translation stages. Spring clips are also rotatable to accommodate easy
swapping of petri dishes and glass slides.
ITEM #
MAX3SLH
$
$ 150.00
£
£ 108.00
ERMB
E 130,50
¥ 1,195.50
MAX3SLH
Shown Mounted on MAX311D
Nanopositioning Stage Holding
R1L3S3P Grid Distortion Target
DESCRIPTION
Microscopy Slide Holder
www.thorlabs.com
1827
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Optical Delay Line
Features
n
n
Optical Tweezers
n
Optical Delay Line
n
n
Supercontinuum
n
n
t SECTIONS
Optical Delay Range: 1466 ps
Delay Sensitivity: 0.67 fs
Computer Control via APT Software
Incorporates the DDS220 Long Travel Stage (See Page XXX)
Input Beam Height (Adjustable using Periscope): 2.4" – 6" (60 mm – 152 mm)
Output Beam Height: 2.4"
Software Interface Included
ODL220-FS
Breadboard Sold Separately
Optical Delay Line
Thorlabs’ ODL220-FS Free-Space Optical Delay Line Kit offers customers
a tested set of Thorlabs components to build an optical delay line. The kit is
based on our DDS220 long-travel, low-profile direct drive stage, capable of
tuning the optical delay up to 1466 ps. Repeatable delay shifts down to
0.67 fs are achievable. The high accuracy and long-term stability of the
stage make this system a suitable choice for pump-probe spectroscopy, THz
spectroscopy, interferometry, and related applications.
The direct-drive technology used in this delay line kit eliminates the need for
a lead screw, which enables backlash-free operation. The absolute position of
the stage is determined using a high-resolution, closed-loop optical feedback
signal that provides bidirectional repeatability of 0.25 µm. The stage also
features twin, precision-grooved linear bearings that provide superior linearity
and on-axis accuracy, which makes the stage an ideal choice for a delay line
setup.
The Optical Delay Line Kit includes a periscope assembly that can
accommodate input beam heights from 2.4" - 6" (60 mm - 152 mm).
By purchasing additional Ø1" RS Series Pillar Posts (see page XXX), the
input beam height that can be accommodated is easily increased. The first
POLARIS-K1 Mirror Mount is used to align the beam to be parallel to
the translation axis of the DDS220 direct drive stage. The stage’s V-block,
containing two kinematic mirror mounts, facilitates alignment on the stage.
Finally, a second POLARIS-K1 mount is then used to steer the output beam.
Six Ø1" protected silver mirrors, which provide an average reflectivity in
excess of 96% over the entire 450 nm - 2 µm range, are included. If your
application would benefit from gold, aluminum, broadband dielectric,
dielectric laser line, or ultrafast mirrors, please contact technical support at
[email protected] to discuss the various options.
1828
www.thorlabs.com
ODL220-FS
Optical Path
Advanced
Applications
Optical Delay Line
DDS220
Direct Drive Stage
Kit Components
Direct Drive, Linear Translation Stage
(DDS220, See Page XXX)
n Benchtop 3 Phase Brushless DC Servo Controller
(BBD101, See Page XXX)
n Two Ultra Stable Kinetic Mirror Mounts
(POLARIS-K1, See Pages XXX - XXX)
n Periscope Assembly
(RS99, See Page XXX)
n Six 1" Protected Silver Mirrors
(PF10-03-P01, See Page XXX)
n Custom V-Block
n Thorlabs Software Included
n
CHAPTERS
t
Frequency
Stabilization
Atomic Force
Microscope
Optical Tweezers
Optical Delay Line
Supercontinuum
DDS220 STAGE*
Travel Range
220 mm (8.6")
Speed (Max)
300 mm/s
5000 mm/s2
Acceleration (Max)
Bidirectional Repeatability
SECTIONS t
Optical Delay Line
±0.25 µm
Backlash**
N/A
Incremental Movement (Min)
0.1 µm
Absolute On-Axis Accuracy
±2.0 µm
Home Location Accuracy (Unidirectional)
±0.25 µm
Bearing Type
Precision Linear Bearing
Motor Type
Brushless DC Linear Motor
Dimensions
370 mm x 90 mm x 45 mm
(14.6" x 3.5" x 1.77")
*See page XXX for more information.
**The stage does exhibit backlash since it does not utilize a leadscrew.
BBD101 CONTROLLER*
Control Algorithm
BBD101
Controller Included
Velocity Profile
Trapezoidal/S-Curve
Position Feedback
Incremental Encoder
Encoder Bandwidth
Input Power Requirements
The optical delay line includes the apt™ software package
for computer control of the stage. This apt™ software
also allows for advanced custom control applications and
sequences in various programming languages through Active
X. Also included is software with a GUI (shown below) to
control timing changes to the stage. With this software,
it is possible to precisely choose the optical delay you wish
to add or subtract from your beam path. For interferometry
experiments, the option to scan the stage continuously or
in discrete steps, with each step’s position being held for a
specific time period, is available.
16-Bit Digital PID Servo Loop with
Velocity and Acceleration Feedforward
Dimensions
2.5 MHz (10 M Counts/s)
250 VA
Voltage: 85 to 264 VAC
Frequency: 47 to 63 Hz
Fuse: 3.15 A
174 mm x 245 mm x 126 mm
(6.85" x 9.65" x 4.96")
*See pages XXX for more information.
Applications
Pulsed Pump/Probe Experiments
Auto-Correlation, Cross-Correlation, and
Optical Sampling
n Pulse Synchronization
n Interferometric Sensors and Instruments
(See Our FT-OSA Spectrometer on Pages XXX - XXX)
n Coherent Communication Systems
n Reconfigurable Switching, Buffering, and Processing
n
n
ITEM #
ODL220-FS
$
$ 7,500.00
£
£ 5,400.00
ERMB
e 6.525,00
¥ 59,775.00
ODL220-FS/M
$ 7,500.00
£ 5,400.00
e 6.525,00
¥ 59,775.00
DESCRIPTION
Free-Space Optical Delay Line
Free-Space Optical Delay Line Metric
www.thorlabs.com
1829
Advanced
Applications
t CHAPTERS
Frequency
Stabilization
Atomic Force
Microscope
Optical Tweezers
Optical Delay Line
Supercontinuum
t SECTIONS
Supercontinuum
Supercontinuum Generation Kit
Thorlabs’ Supercontinuum Generation Kits use FemtoWhite highly nonlinear fibers to spectrally broaden femtosecond pulses near 800 nm.
The SCKB(/M) produces an output beam that combines the high power and spatial coherence of a laser with
the broad spectrum of an incandescent source. The SCKB-CARS(/M) provides a stable beam with peaks at two
separate center wavelengths.
When pumped with a femtosecond Ti:Sapphire Laser, the SCKB(/M) produces smooth, stable output
providing even intensity across the 400 - 1600 nm spectral range, as shown in the plot below. The
shape and intensity of the supercontinuum is determined by the pump wavelength, peak power,
and pulse length.
SCKB
Breadboard
Sold Separately
Depending on the relative distance from the zero dispersion
wavelength of the fiber, a variety of nonlinear effects are responsible
for the creation of the spectrum; these effects include self-phase
modulation, Raman scattering, soliton fission, and fourwave mixing. Please refer to J.M. Dudley, G. Genty,
S. Coen, “Supercontinuum generation
in photonic crystal fiber” Rev.
Mod. Phys. 78, 1135 (2006) for
a review of these effects in
photonic crystal fibers.
Features
n
n
n
n
n
400 – 1600 nm Output Spectrum
Optimized for 800 nm Femtosecond
Pulsed Ti:Sapphire Lasers
Utilizes FemtoWhite Highly Nonlinear
Fiber
Includes Custom Broadband Optical
Isolator to Protect Input Laser Source
CARS Version Available
Major Kit Components*
n
n
n
n
n
n
n
n
Nonlinear Fiber Cell (SCKB-FW800 or
SCKB-FWCARS)
Custom Free Space Isolator (See Page XXX)
MicroBlock 3-Axis Stage (MBT616D, See Page XXX)
Olympus Objectives
(RMS20X and RMS40X, See Page XXX)
Periscope Assembly (RS99, See Page XXX)
Polaris™ Ultra Stable Mirror Mounts
(POLARIS-K1, See Pages XXX - XXX)
Glan-Laser Calcite Polarizer (GL10-B, See Page XXX)
Mounted Achromatic Half-Wave Plate
(AHWP05M-980, See Page XXX)
Beam Traps (BT610, See Page XXX)
*All items shown in the picture are included,
except for the breadboard.
Spectral Output
-40
Relative intensity (dB)
n
-50
-60
-70
-80
Coupled average power: 67 mW
Pump Wavelength : 800 nm
Pulse duration: 50 fs
Rep. Rate: 79 MHz
-90
-100
400
600
800
1000
1200
Wavelength (nm)
Dispersed Supercontinuum Generated
with Coherent’s Chameleon Ti:Sapphire
Laser and the SCKB Supercontinuum
Generation Kit.
1830
www.thorlabs.com
1400
1600
Advanced
Applications
CHAPTERS
The SCKB-CARS(/M) contains a fiber with two zero-dispersion wavelengths for generation of an output with two distinct peaks,
suitable for Coherent Anti-Stokes Raman Scattering applications. When pumped at a wavelength between the two zero-dispersion
wavelengths, more than 99% of the light is converted into two spectral peaks.
Frequency
Stabilization
Atomic Force
Microscope
The peak wavelengths are a result of the two zero-dispersion wavelengths that are determined solely by the design of the nonlinear
PCF fiber. Due to this, the output wavelength is insensitive to changes in pump wavelength, pulse energy, pulse width, and spectral
bandwidth. However, the relative intensity of the two peaks can be adjusted by varying of the pump wavelength.
Optical Tweezers
Optical Delay Line
For more information, please see K. M. Hilligsøe, T. V. Andersen, H. N. Paulsen, C. K. Nielsen, K. Mølmer, S. Keiding, R. E.
Kristiansen, K. P. Hansen, and J. J. Larsen, “Supercontinuum Ceneration in a Photonic Crystal Fiber with two Zero Dispersion
Wavelengths” Opt. Express 12, 1045 (2004).
Supercontinuum
SECTIONS t
Relative
Output
Power
Typical Dispersion
t
Supercontinuum
Max
20
1400
Wavelength (nm)
Dispersion (ps/nm/km)
0
-20
-40
1200
1000
800
-60
600
-80
Min
0.2
700
750
800
850
900
950
1000
1050
0.2
1100
0.4
0.6
0.8
1
Energy (nJ)
Wavelength (nm)
Output Spectra versus Pulse Energy for
FemtoWhite-Cars Pumped at 790 nm with 50 fs Pulses
ITEM #*
SCKB
$
$ 14,490.00
£
£ 10,432.80
ERMB
E 12.606,30
¥ 115,485.30
DESCRIPTION
Supercontinuum Generation Kit
SCKB/M
$ 14,490.00
£ 10,432.80
E 12.606,30
¥ 115,485.30
Supercontinuum Generation Kit - Metric
SCKB-CARS
$ 16,200.00
£ 11,664.00
E 14.094,00
¥ 129,114.00
CARS-Suitable Supercontinuum Generation Kit
SCKB-CARS/M
$ 16,200.00
£ 11,664.00
E 14.094,00
¥ 129,114.00
CARS-Suitable Supercontinuum Generation Kit - Metric
*Please contact our technical support group if you wish to order the kit preassembled.
Have you seen our...
Dispersion-Compensating Optics
Mirror Sets
Prism Pairs
θ
B
◆Group Velocity Dispersions
◆ Operating Wavelength Range: 700 - 1000 nm
◆ Reflectivity: >99.5%
◆ Dispersion per Reflection (@ 800 nm): -175 fs2
Thorlabs’ dispersion-compensating mirror sets are specifically
designed so that longer wavelengths experience larger group
velocity delay than shorter wavelengths, thereby negating the
pulse broadening caused by other optical elements.
See page XXX
(@ 800 nm):
• CaF2: -5 fs2/cm
• Fused Silica: -16.5 fs2/cm
• SF10: -97.5 fs2/cm
• N-SF14: -113.5 fs2/cm
λ Long
λ Center
λ Short
To achieve the specified Group Velocity Dispersion while maximizing
transmission, light should be incident on the first prism at Brewster’s Angle
(ΘB). As shown in the schematic, the first prism is used to separate the various
wavelength components. Then, a second prism is positioned such that the
various wavelengths of refracted light will propagate parallel to each other upon
exiting the second prism but with a wavelength-dependent position referred to
as spatial chirp.
See page XXX
www.thorlabs.com
1831