System Schematic
Hardware Description
| BMC’s deformable mirror(DM) technology is used as the central component in the WS-AOD-B to compensate for phase aberrations. The BMC DM is a continuous facesheet deformable mirror that is controlled by hysteresis-free electrostatic acutators located on a square grid. The full DM active aperture can be as little as 1.5 mm to as much as 25 mm across. Each actuator can provide up to 5.5 µm of mechanical stroke, which corresponds to about 11 µm of phase control. The electrostatic actuator array is driven using independent high voltage channels with 14-bit resolution. This corresponds to sub-nanometer displacement precision. The drive electronics can provide frame rates from about 4.6 kHz up to 100 kHz. |
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Measurements of the on-axis intensity metric used by the controller are performed using a Thorlabs PDA36A silicon photodetector. The pinhole used to sample the on-axis beam intensity is placed directly above the active photodetector area. The photodetector output voltage is acquired using a multifunction measurement board that is configured to read a single-ended analog input channel with 12-bit resolution. The board interfaces with the PCI bus of a standard PC and communicates data to the system control software at an average data rate of 6 kHz. |
| The demonstration system also includes a Thorlabs DCU223M monochrome CCD camera to image the point-spread function of the focused beam. The camera-to-PC interface is a USB 2.0 connection, providing full resolution images (1024 × 768 pixels) at a frame rate of 30 Hz. |
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Software Description
 The control software for the Wavefront Sensorless Adaptive Optics Demonstrator-Beam Shaping is open source code based in Mathwork’s Matlab, Release 2007a, and runs on platforms using Windows operating systems. The software interfaces with the deformable mirror drive electronics and CCD camera via a USB 2.0 connection, and the photodetector data acquisition board via the PCI bus. The software allows the user to correct for aberrations introduced as well as generate a random aberration using the DM. The interface consists of the standard Matlab entry screen as well as a live image of the CCD camera signal and plot of the previous system convergence. The closed-loop frame rate measured for the system using the hardware and layout described with a Multi-DM system is 720 Hz.
Customization Opportunity
The Wavefront Sensorless AO Demonstrator is a fully- customizable instrument. BMC can tailor the system for researchers and scientists with existing setups and applications. Please contact us to arrange a meeting to discuss how the WS-AOD can be customized for you
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Typical Performance
Left: Image of focused beam with aberration applied to a Multi-DM. Right: Image of focused beam with flattened Multi-DM. This performance is typical of low perturbation and gain inputs to the SPGD controller. |
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WS-AOD-B Standard Components
- BMC deformable mirror*
- Photodetector
- Photodetector data acquisition board
- Monochrome CCD camera
- T-cube laser source
- All optical components for system including lenses, mounts, translation stages, irises, etc.
* Standard configurations with Mini-DM, Multi-DM or Kilo-DM are available |
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WS-AOD-B Options
- Demo-in-a-box:
Includes
Mathworks’ MATLAB©-single license and DAQ Toolbox
Full installation with included Dell© PC
- Fundamentals Kit:
Includes DM*, data acquisition board and software only
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