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MesaPhotonics VideoFROG FROGscan User Manual

Realtime ultrashort pulse measurement
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FROGscan products are protected by United States patents 8068230, 7130052, 6219142

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Summary of Contents for MesaPhotonics VideoFROG FROGscan

  • Page 1 FROGscan products are protected by United States patents 8068230, 7130052, 6219142...
  • Page 3 Tel: +1 505 216 5015 Fax: +1 866 569 6994 E-mail: support@mesaphotonics.com. Mesa Photonics, LLC, ©2003-2018. All Rights Reserved. Mesa Photonics reserves the right to make changes to the FROGscan system and the User’s Manual at any time and without prior notice. As manuals and instructions are updated, omissions may occur.

  • Page 5: Table Of Contents

    Contents Chapter 1. Overview ............................. 1 1.1 General Information..........................1 1.2 Safety Considerations ......................... 1 Optical radiation hazards ........................1 Electrical hazards........................... 1 1.3 Specifications ............................2 Environmental ............................2 Operational ............................2 Instrument Specifications........................2 1.4 FROGscan System Components and Beam Path ................3 Chapter 2.
  • Page 6 6.2 Changing the Spectrometer ......................46 6.3 Installing a Reflective Fiber Collimator ....................47 Chapter 7. Retrieving Pulses ........................50 7.1 Optimizing Pulse Symmetry ......................50 7.2 Centering the FROG Trace in time....................50 7.3 Adjusting the Grid Size ........................50 7.4 Setting the Background Level ......................

  • Page 7: Chapter 1. Overview

    Chapter 1. Overview Chapter 1. Overview 1.1 General Information FROGscan is a high-performance ultrashort laser pulse measurement system that runs under VideoFROGscan (VFS) laser pulse measurement software. It uses a unique combination of a high performance servo delay line and a high performance, compact spectrometer. This combination provides real-time performance and high dynamic range.

  • Page 8: Specifications

    Chapter 1. Overview 1.3 Specifications Environmental Operating temperature: +10° C to +40° C Storage temperature: -30° C to +70° C Humidity: 95% non-condensing Operational Computers vary widely in their characteristics and performance. The exact pulse retrieval rate depends on many factors including the speed of the processor, the speed of the bus, the speed of the memory, and the graphics card.

  • Page 9: Frogscan System Components And Beam Path

    Chapter 1. Overview 1.4 FROGscan System Components and Beam Path 1= Entrance Iris 2= Center Iris 3= Beam Splitter 4= Servo Mirror 5= Focusing Mirror 6= Fixed Delay Mirror 7= Overlap Mirror 8= Exit Iris/Fixed Delay Beam Camera 9= Focusing Mirror Camera 10= Diverter Mirror 11= 1 Turning Mirror...

  • Page 10: Chapter 2. Setup

    Chapter 2. Setup Chapter 2. Setup 2.1 Inspecting the FROGscan Shipment Contents Inspect the contents of the FROGscan box, which contains the following: 1. FROGscan Device. 2. Power Supply, Power Cable and Mini XLR Power Supply plug. 3. 2 USB Cables (for the Spectrometer and Servo Motor). 4.

  • Page 11: Installing Videofrogscan Software

    Chapter 2. Setup To free the crystal: Follow the steps shown in the Figure 3 below. (a) Release the crystal by pulling out the knurled head of the locking screw. (b) Rotate the locking screw 90˚. (c) The Crystal Tilt is now in the unlocked position. (d) Carefully place one fingertip on top of the crystal frame and verify that it is free to rotate a few degrees in either direction.
  • Page 12 Chapter 2. Setup Follow these steps: 1. Insert the USB Flash drive into a USB port on your computer. 2. Open the VideoFROGscan 9 folder and right click on the VideoFROGscan 9 application. Select Run as Administrator. 3. In the User Account Control Window, click on Yes to allow the app to make changes to the computer.
  • Page 13 Chapter 2. Setup 6. In the Customer Registration window input the User Name and Organization, then click Next. 7. The default Destination Directory is C:\Program Files\Mesa Photonics\VideoFROG Scan 9 - NC. It is highly recommended not to change the Destination Directory. Click Next to accept the directory.
  • Page 14 Chapter 2. Setup 9. Click Next in the Completing the InstallAware Wizard Window to start the installation and configuration. The installation will take several minutes. 10. Read the information in the Important Information Window pertaining to the USB connections from the computer to the FROGscan.
  • Page 15 Chapter 2. Setup 11. The installation program will install the Drivers for both the FTDI and the Ocean Optics Spectrometer. Click on Extract to start the process for the FTDI drivers. 12. Wait until the drivers are extracted. 13. Click on Next in the Device Driver Installation Wizard to start the FTDI driver Installation.
  • Page 16 Chapter 2. Setup 14. Click on I accept this agreement to accept the License Agreement in the Device Driver Installation Wizard. 15. Wait while the FTDI Drivers install. 16. Installation is complete when the Completing Device Driver Installation Wizard Window appears. Click on Finish to close the window.
  • Page 17 Chapter 2. Setup 17. The Ocean Optics Drivers will now install. A Setup window with a progress bar will open to indicate the start and progress of the Omni Driver. 18. Part of the Ocean Optics driver installation includes Microsoft Visual C++.
  • Page 18 Chapter 2. Setup If your FROGscan instrument includes the optional Camera Alignment system, the software will load the Camera Drivers. Otherwise, continue with Step 25. 20. The VideoFROGscan 9 – WC InstallAware Wizard will open. Follow the instructions in the open Window by plugging both USB Cables from the FROGscan device to the computer and allowing the...
  • Page 19 Chapter 2. Setup 23. When the Installation is complete, click on Finish in the Driver Installation Window. 24. Ensure the RegSvr32 window opens and then click on OK. The software will now continue with the installation of LabView Run Time Engine. Continue with the following installation steps for FROGscan Instrument with or without cameras.
  • Page 20 Chapter 2. Setup 27. Click on OK to acknowledge that the extractor unzipped 315 files. The installation will now begin. 28. Click Next in the NI LabVIEW Run Time Engine Installation window. 29. The default Destination Directory is C:\Program Files\National Instruments.
  • Page 21 Chapter 2. Setup 30. In the Features Window, click Next to accept all the default features. 31. In the Products Notification Window, uncheck Search for important messages… then click Next. 32. Accept the National Instruments License Agreement by selecting I accept the License Agreement Then click Next.
  • Page 22 Chapter 2. Setup 33. Click Next in the Start Installation Window. The installation may take a few minutes to complete. 34. Click on Finish when the Installation Complete Window is displayed. 35. Close all open windows, then reboot the computer. 36.

  • Page 23: Opening The Videofrogscan Software Program

    Chapter 2. Setup 2.4 Opening the VideoFROGscan Software Program Now that VideoFROGscan has installed, follow these steps to open the program on your computer: 1. Connect the power supply to FROGscan. If the USB cables were connected as part of the VideoFROGscan installation, disconnect the USB cables before running VideoFROGscan for the first time.

  • Page 24: Chapter 3. Program Menus

    Chapter 3. Program Menus Chapter 3. Program Menus Now that VideoFROGscan has been uploaded, please familiarize yourself with the program menus. VideoFROGscan has been carefully designed to provide near turnkey operation while providing the user with very sophisticated options for FROG pulse retrieval. New as of Version 8 is an entirely new, more intuitive user interface that uses a tabbed interface to allow different operating windows to be displayed.
  • Page 25 Chapter 3. Program Menus Figure 4: Main Menu with several data saving options and hardcopy output. The directory where the data is saved is set in the VideoFROGscan Configuration program. Figure 5: Operate menu with options for program operation. Figure 6: Help menu with options for support. 09/07/2018 Vs 003 FROGSCAN USER’S MANUAL Page 19...

  • Page 26: Left Control Panel

    Chapter 3. Program Panels 3.2 Left Control Panel Remember to activate popup windows containing more detailed information by clicking on the desired heading. Video FROGscan data is displayed in eight different Panels. Each of these Panels displays a panel on the left in which the following parameters can be set: Time Center ̶...
  • Page 27 Chapter 3. Program Panels Figure 7. Important settings can be entered on the control panel on any of the eight Menu Panels. 09/07/2018 Vs 003 FROGSCAN USER’S MANUAL Page 21...

  • Page 28: Quitting Videofrogscan Software

    Chapter 3. Program Panels 3.2.1 Quitting VideoFROGscan software VideoFROGscan can be exited from any panel by clicking the QUIT (Exit) button on the top right of the front panel. This allows the program to stop correctly and close all drivers. Do not close down VideoFROGscan by clicking on the “X”...

  • Page 29: Summary Panel

    Chapter 3. Program Panels 3.3 Summary Panel Clicking on the plots will bring up popup windows of the plots (except for the autocorrelation on the right) and a more detailed description of the function (see Figure 10). Double clicking on the FROG Results opens a floating FROG Results window.

  • Page 30: Data Acquisition Panel

    Chapter 3. Program Panels 3.4 Data Acquisition Panel Most of the program settings can be set in this Panel. Time Calibration – The servo calibration constant in femtoseconds per step; each step is ~ 1 fs or 150 Grid Size – Determines the size of the FROG Trace sent to the retrieval algorithm. For example, when a 64 x 64 array is selected, the region inside the square on the raw video display is resampled to a 64 x 64 pixel array before the pulse characteristics are extracted from the FROG Trace.
  • Page 31 Chapter 3. Program Panels 3 Frame Background – Requires one dark frame for each beam being blocked. This can be complicated, and is only needed when one or both of the beams is creating scatter in the spectrometer. Background Frames to Average – sets the number of background frames to be averaged for the 3 Frame Background subtraction.

  • Page 32: Automated Crystal Tilt Function

    Chapter 3. Program Panels 3.4.1 Automated Crystal Tilt Function In instruments with Autotilt function, the crystal tilt settings are entered in the Data Acquisition Panel. The crystal tilt is controlled using a direct drive, five pole stepper motor designed specifically for microstepping.

  • Page 33: Setup And Alignment Panel

    Chapter 3. Program Panels 3.5 Setup and Alignment Panel The intensity of the signal is displayed in this Panel, which is used when the intensity of the Signal Beam is maximized (Chapter 5). Raw Spectrum (red) – Displays the spectrum recorded by the spectrometer. Center Spectrum (green) –...
  • Page 34 Chapter 3. Program Panels Figure 14. Setup and Alignment Panel. The wavelength range a given spectrometer is able to read is automatically displayed on the x-axis. Page 28 FROGSCAN USER’S MANUAL 09/07/2018 Vs 003...

  • Page 35: Pulse Display Panel

    Chapter 3. Program Panels 3.6 Pulse Display Panel The retrieved pulses are displayed in two separate windows (see Figure 15). The Temporal Panel displays the temporal intensity and phase, and the Spectral Panel (not shown) displays spectral intensity and phase. Each window contains the plot area as well as the plot menu. Shown are the Pulse Width, the Time Bandwidth Product (TBWP), and the FROG Error.

  • Page 36: Pulse Analysis Panel

    Chapter 3. Program Panels 3.7 Pulse Analysis Panel The Measured and Retrieved FROG Traces are displayed as in the Summary Panel (see Section 3.3). This Panel contains various controls: Bar Graph: Shows the spectral dispersion coefficients calculated from a linear least squares fit to the spectral phase.

  • Page 37: Program Information Panel

    Chapter 3. Program Panels 3.8 Program Information Panel Various program settings and operations can be checked in the Program Information Panel (see Figure 17). Retrieved Stats – Displays the retrieved pulse statistics. VI Name and Application Name – Program information only required if the program is not operating correctly.

  • Page 38: Frog Trace Panel

    Chapter 3. Program Panels 3.9 FROG Trace Panel The steps required for measuring an ultrafast laser pulse using FROGscan first involve first obtaining all the spectra required to build up the raw FROG Trace. At each time delay, a single spectrum is taken, with N time delays taken, where N x N is the grid size for the resampled FROG Trace.

  • Page 39: Error Analysis Panel

    Chapter 3. Program Panels 3.10 Error Analysis Panel Under this Panel, the plots of the measured and retrieved frequency and time marginals are displayed. For good retrievals and measurements, the measured and retrieved marginals are the same. Figure 19. Screenshot of the Error Analysis Panel. 09/07/2018 Vs 003 FROGSCAN USER’S MANUAL Page 33...

  • Page 40: Chapter 4. Aligning A Laser Beam Into Frogscan

    Chapter 4. Aligning a LASER Beam into FROGscan Chapter 4. Aligning a LASER Beam into FROGscan FROG Scan is factory aligned and in most cases all that is required to obtain a FROG signal is  Proper alignment of the LASER beam into FROGscan ...
  • Page 41 Chapter 4. Aligning a LASER Beam into FROGscan The Center Iris can be removed after initial alignment if it is blocking part of a beam that is wider than 8 mm. Ensure that the input laser is blocked and that laser light is not entering into FROGscan. Remove the Center Iris by twisting it counterclockwise.

  • Page 42: Aligning A Laser Beam Into Frogscan Using Alignment Cameras

    Chapter 4. Aligning a LASER Beam into FROGscan 4.2 Aligning a LASER Beam into FROGscan using Alignment Cameras The camera alignment option was added to FROGscan systems to simplify LASER beam alignment into FROGscan. The camera on the right (Focusing Mirror Camera, see Figure 1) is positioned such that the distance between the Focusing Mirror –...
  • Page 43 Chapter 4. Aligning a LASER Beam into FROGscan Figure 22. Clicking Alignment Mode to ON turns off data acquisition and pops up an image viewer for the beam cameras. Figure 23. Screen capture of the alignment screen. In this image the Fixed Delay Beam appears in the lower half of the screen because the FROG instrument...

  • Page 44: Chapter 5. Maximizing The Intensity Of The Signal Beam

    Chapter 5. Maximizing the Intensity of the Signal Beam Chapter 5. Maximizing the Intensity of the Signal Beam Once initial alignment is achieved, the SHG beams should be visible by eye on a fluorescing card or with the aid of a viewer if the instrument is set up correctly. The setup process then continues to: 5.1 Optimizing the crystal tilt.

  • Page 45: Optimizing The Crystal Tilt

    Chapter 5. Maximizing the Intensity of the Signal Beam 5.1 Optimizing the Crystal Tilt 1. Ensure that your LASER has the same horizontal polarization as the crystal. If the crystal cut angle corresponds to the Theta angle for a particular wavelength, the crystal will be vertical. When the crystal cut angle corresponds to the phase matching angle for the input wavelength.

  • Page 46: Optimizing The Entry Of The Signal Beam Into The Spectrometer

    Chapter 5. Maximizing the Intensity of the Signal Beam 5.2 Optimizing the Entry of the Signal Beam into the Spectrometer FROGscan Ultra contains additional optics behind the crystal as compared to FROGscan Standard (see Figure 1 and 20, respectively). The spectrometer alignment procedure is therefore described for each instrument separately, although the principle is the same.

  • Page 47: Optimizing The Time Center On The Instrument

    Chapter 5. Maximizing the Intensity of the Signal Beam 5.3 Optimizing the Time Center on the Instrument 1. Check the paperwork from the Factory to ensure that the Time Center number for temporal overlap is entered correctly in the Summary Panel. 2.

  • Page 48: Troubleshooting

    Chapter 5. Maximizing the Intensity of the Signal Beam 5.4 Troubleshooting The Signal beam is not visible. The Signal beam will appear only when the beams overlap in the crystal. Therefore, the device must be aligned for simultaneous temporal overlap and spatial overlap, which can be very difficult. The following approaches have been used successfully: 1.

  • Page 49: Chapter 6. Installing And Changing Hardware

    Chapter 6. Installing and Changing Hardware Chapter 6. Installing and Changing Hardware FROGscan systems enable data acquisition at different wavelengths without the need for purchasing a separate instrument. All that is needed to switch between different wavelength measurements is to change the crystal and the spectrometer.
  • Page 50 Chapter 6. Installing and Changing Hardware Figure 27. Change Crystal button in the Setup and Alignment Panel. 2. Open and carefully lift the FROGscan cover and follow the steps below. 1. With the 5/64 Ball point Hex L-key 2. Remove the loosened 3.
  • Page 51 Chapter 6. Installing and Changing Hardware Install the new Crystal 5. Carefully, slide the Crystal Cartridge into the Crystal Mount, taking note of the location of the microSD Card with respect to the SD Card slot. 6. Ensure that the microSD Card has fully engaged into the SD Card slot by gently pushing on the top of the Crystal Cartridge.

  • Page 52: Changing The Spectrometer

    Chapter 6. Installing and Changing Hardware 6.2 Changing the Spectrometer One of the specified spectrometers was installed into FROGscan at the factory and can easily be changed if more than one spectrometer was purchased in order to obtain data at different wavelengths. Each spectrometer is already mounted on its own baseplate so that only the baseplate/spectrometer assembly is replaced.

  • Page 53: Installing A Reflective Fiber Collimator

    Chapter 6. Installing and Changing Hardware 6.3 Installing a Reflective Fiber Collimator If your LASER is guided through a fiber collimator, Mesa Technologies will supply you with a kinematic mount that fits in the Thorlabs cage rod system, 4 short cage rods, an adaptor, and a fiber collimator (usually reflective).
  • Page 54 Chapter 6. Installing and Changing Hardware Kinematic mount that fits in the Thorlabs cage rod 4. Install four (4) Cage Assembly Rods to the system, adapter, and a fiber collimator. 4-40 tapped holes surrounding Entrance Iris. 5. Secure the Kinematic Mount to the Rods by The Adapter is installed in the mount at the tightening the set-screws on both sides of the factory.
  • Page 55 Chapter 6. Installing and Changing Hardware 8. Use the Locking Ring on the Kinematic Mount to 9. The final assembly should look like this. secure the Collimator in place. 09/07/2018 Vs 003 FROGSCAN USER’S MANUAL Page 49...

  • Page 56: Chapter 7. Retrieving Pulses

    Chapter 7. Retrieving Pulses Chapter 7. Retrieving Pulses Once the system is aligned and FROG Traces are appearing on the raw video display, pulses will be automatically retrieved by the VideoFROGscan software. Through the use of controls on the Panel, the measured FROGscan Trace can be adjusted and optimized.
  • Page 57 Chapter 7. Retrieving Pulses Too much background. This Trace contains too much speckle (light blue) If you are unsure about the adjustment, or see what you think is too much blue speckle, error on the side of too much blue speckle. b) Too much clipping Because the Live View is on while the adjustment is being made, it is easy to see the change in the size of...
  • Page 58 Chapter 7. Retrieving Pulses The best way to remove background is to set the background level in VideoFROGscan. This is a very important and relatively simple adjustment. Thus, it is worth a few minutes of your time to become familiar with this adjustment.
  • Page 59 Chapter 7. Retrieving Pulses To determine if the measurements are good, two different checks can be useful. 1. Check the FROG Trace error, although this can sometimes be misleading. Typically, the FROG Trace error should be below about 1-2% for small grids and less than 1% for larger grid sizes;...

  • Page 60: Chapter 8. Warnings

    Chapter 8. Warnings Chapter 8. Warnings The following warnings may appear in the bottom of the left panel. 8.1 Spatial Chirp Spatial Chirp usually only occurs in amplified ultrafast laser pulses when the stretcher and the compressor of an amplifier are not well aligned. While FROGscan cannot quantitatively measure spatial chirp, it can provide an excellent qualitative indication of the spatial chirp.

  • Page 61: Frog Trace Clipped

    Chapter 8. Warnings Turn on the time centering by clicking the Time Offset Correction on (under the Control Menu in the Data Acquisition Panel). Be sure the background subtraction is on. 8.6 FROG Trace Clipped VideoFROGscan can sense when the FROG Trace is being vignetted or clipped. The clipping can occur either along the wavelength axis or the time axis.

  • Page 62: Background

    Chapter 8. Warnings 8.8 Background This warning appears either when the background was not subtracted or when settings were changed such that the background must be taken again. Sometimes, the adjustments are small enough so that that background looks OK. If this is the case, you can ignore the warning. Quick Fix: Re-take the background.
  • Page 63 Chapter 8. Warnings The program seems to hang while displaying the …FTDI USB-RS232 message in the warning display. This usually happens when the program does not exit properly, and the communication systems have not closed out properly. Click the red “X” in the upper right hand corner of the VideoFROGscan program window, to completely exit the program.

  • Page 64: Chapter 9. Customization

    Chapter 9. Customization Chapter 9. Customization 9.1 Data Pipes VideoFROGscan supplies access to "pipes" to access the retrieved pulse and resampled trace while the program is running in real-time. This allows running concurrent programs that have access to the data. These could be error analysis, database, or a variety of other programs such as those used to save data in any chosen format.

  • Page 65: Chapter 10. Literature

    Chapter 10. Literature Chapter 10. Literature Papers: 1. Measuring ultrashort laser pulses in the time-frequency domain using frequency-resolved optical gating Rick Trebino, Kenneth W. DeLong, David N. Fittinghoff, John N. Sweetser, Marco A. Krumbügel, Bruce A. Richman, Daniel J. Kane Review of Scientific Instruments 68, 3277 (1997);...

  • Page 66: Chapter 11. Appendices

    Chapter 11. Appendices Chapter 11. Appendices Appendix A: Pinout for Analog and Digital I/O Pin Number Pin Name Notes Analog Channel 1 + 16-bit A/D differential input (+) +/- 2V max Analog Channel 1- 16-bit A/D differential input (-) Analog Channel 2+ 16-bit A/D differential input (+) +/- 2V max Analog Channel 2- 16-bit A/D differential input (-)

  • Page 67: Appendix C: Function Reference For The Pcgpmonitor Dll

    Chapter 11. Appendices Pulse_Freq_Domain (date and time).txt – Frequency or Spectral domain retrieved pulse File Format: ASCII, space delimited Four columns of data: 1) Frequency axis (in Petahertz) 2) Wavelength axis (in nanometers) 3) Spectral intensity Spectral phase Pulse_Complex_Time_Domain (date and time).txt – Complex (real and imaginary) version of the time domain retrieved pulse File Format: ASCII, space delimited Three columns of data:...
  • Page 68 Chapter 11. Appendices Function Descriptions: double __stdcall GetPulseWidth(void) Calling sequence: None. This subroutine returns the pulse width. int __stdcall GetSize(void) Calling sequence: None. This subroutine returns the size of the FROG Trace. void __stdcall ReturnPulseParams(double *PulseParams) Calling sequence: PulseParams is a pointer to a 4 element double float array to receive all of the pulse parameters. This subroutine is void (returns nothing).
  • Page 69 Chapter 11. Appendices void __stdcall ReturnSpec(double *Spec) Calling sequence: Spec is a pointer to double float array, double (64 bit float) of length isize*isize to receive the spectrogram used in the inversion. This subroutine is void (returns nothing). All data is passed in the previously allocated double array. void __stdcall GetIntensityandPhase(double *pulse, double *tdI, double *tdP, double *fdI, double *fdP, int N) This function returns the intensity and phase in the time and frequency domain when provided a raw,...
  • Page 70 Chapter 11. Appendices Appendix D: Warranty Term and Coverage: For a period of twelve (12) months from the date of shipment (the “Instrument Warranty Period”), we warrant that our instruments are free from defects in materials and workmanship (the “Warranty”). During the Instrument Warranty Period, except otherwise indicated by us in a quotation, we will provide the following services at no additional charge: ...

  • Page 71: Appendix E: Calibration Sheets

    Chapter 11. Appendices Appendix E: Calibration Sheets Appended in the following are screenshots and calibration sheets for your instrument. FROGscan Calibration Sheet Servo Calibration Sheet VideoFROGscan screen captures Spectrometer Wavelength Calibration Sheet Spectrometer Linearity Test Sheet Hollow Retroflector Calibration Sheet (where applicable) 09/07/2018 Vs 003 FROGSCAN USER’S MANUAL Page 65...

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