* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Advanced Applications
Chemical imaging wikipedia , lookup
Nonimaging optics wikipedia , lookup
Spectrum analyzer wikipedia , lookup
Astronomical spectroscopy wikipedia , lookup
Ellipsometry wikipedia , lookup
Retroreflector wikipedia , lookup
Photonic laser thruster wikipedia , lookup
X-ray fluorescence wikipedia , lookup
Super-resolution microscopy wikipedia , lookup
Atomic force microscopy wikipedia , lookup
Fiber-optic communication wikipedia , lookup
Silicon photonics wikipedia , lookup
Interferometry wikipedia , lookup
Optical amplifier wikipedia , lookup
Scanning joule expansion microscopy wikipedia , lookup
Vibrational analysis with scanning probe microscopy wikipedia , lookup
Photoconductive atomic force microscopy wikipedia , lookup
Confocal microscopy wikipedia , lookup
Passive optical network wikipedia , lookup
Optical coherence tomography wikipedia , lookup
Nonlinear optics wikipedia , lookup
Photon scanning microscopy wikipedia , lookup
Optical rogue waves wikipedia , lookup
Harold Hopkins (physicist) wikipedia , lookup
Magnetic circular dichroism wikipedia , lookup
3D optical data storage wikipedia , lookup
Ultraviolet–visible spectroscopy wikipedia , lookup
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