Hi-Speed DM97-15 deformable mirror
The ALPAO Hi-Speed DM97-15 features all the benefits of voice-coil technology: linearity, large stroke, no hysteresis with a large bandwidth (>750Hz) and large inter-actuator stroke. All these performances are obtained with a compact mirror thanks to a pitch of 1.5mm between to actuators.
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This is the ideal mirror for applications requiring large strokes and fast temporal response such as astronomy, vision science, free space optics and all adaptive optics without wavefront sensors.
Stroke performances
Thanks to its know-how, ALPAO engineers have designed an adaptive optics with optimized influence functions: a large stroke when all actuators are pushing/pulling in the same directions and in waffle mode.
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| Typical stroke obtained while applying currents (20% of maximal stroke) on 3x3 actuators (mirror suface, half of the wavefront value) |
Typical inter-actuator stroke obtained with 5x5 actuators (the field of view has been reduced because of the dynamic of the wavefront sensor). |
The image on the right shows the typical wavefront amplitudes (peak-to-valley) that are achievable with the Hi-Speed DM97-15.
The Hi-Speed DM97-15 is able to correct very large aberrations like focus but also astigmatism (45µm). |
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Temporal performances
The large bandwidth of the Hi-Speed DM97-15 has been represented hereafter. The figure shows the typical step response featuring a low overshoot and a quick stabilization time. Thanks to a settling time lower of 1 milli-second, it is possible to compensate fast phenomenon encountered such as in astronomy and free space optics. Furthermore, thanks to a quick stabilization, adaptive optics without wavefront sensors are possible using iterative algorithms.
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The ALPAO Hi-Speed DM97-15 features very high stroke with
a very fast stabilization as needed in adaptive optics. |
Drive electronics
The compact Hi-Speed DM97-15 deformable mirror comes with high precision drive electronics. The new ALPAO drive electronics controls the currents (not the voltages) sent to the deformable mirror in order to increase the control precision. Furthermore, thanks to its 14 bits DAC and its high frame rate (>7 kHz), all the benefits of the deformable mirror are used. It features built-in monitoring functions for diagnostic or calibration purposes.
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As this high precision drive electronics is scalable up to 1024 channels, a single drive electronics might be used to control multiple deformable mirrors such as needed in most demanding applications (Multi-Conjugate Adaptive Optics, Multiple Objects Adaptive Optics).
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ALPAO Hi-Speed DM97-15 |
| Clear aperture size |
13.5 mm |
| Number of actuators |
97 |
| Distance between two actuators |
1.5mm |
| Geometry of the actuators |
Square Grid |
| Mirror surface quality in closed loop |
Error < 7.0 nm RMS |
| Wavefront tip/tilt stroke (Peak-to-Valley) |
>+/- 60µm |
| Wavefront astigmatism and focus (Peak-to-Valley) |
> +/- 45µm |
| Wavefront inter-actuator stroke (Peak-to-Valley) |
>3.0 µm |
| Wavefront 3x3 stroke (Peak-to-Valley) |
> +/- 20µm |
| Non linearity errors |
< 3% |
| Bandwidth(1) |
>750 Hz |
| Settling time (at +/- 5%) |
1 ms |
| Coating(2) |
Silver Protected |
| Operating Temperature |
15 - 35 °C |
| Software interface |
C/C++, Matlab, Labview |
| Hardware interface |
PCI I/O Board |
(1) First resonance of the membrane
(2) Other metallic coatings available
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