79-ch 15 mm MMDM with optimised actuator geometry
OKO introduces a 79-channel 15 mm membrane deformable mirror MI4-v1. The device features novel geometry of actuators, specially designed for the best approximation of the low-order Zernike polynomials in the working aperture of 8.7 mm.
The mirror is commercialision of our research and development activities funded by ECSEL in terms of MADEin4 project.
The membrane can be controlled using 2 40-ch standard HV amplifier units connected to 2 USB or Ethernet DAC modules.
Typical specs of the MI4-v1 mirror
Actuator stucture of the mirror features 14 alignment actuators outside the active aperture of 8.7 mm.
These actuators are important for correction of the low-order Zernike plynomials. The actuators inside the aperture are subdivided in 7 concentric rings, with the radii calculated for the optimal approximation of the first 25 Zernike polynomials (see the table below).
Aberrations to be corrected |
Max amplitude (in λ, bidirectional) for the residual shape error of 0.005 λ |
Z4 |
1 |
Z5-Z8 |
0.5 |
Z9 |
0.3 |
Z10-Z15 |
0.2 |
Z16 |
0.15 |
Z17-Z20 |
0.1 |
Z21-z24 |
0.07 |
Z25 |
0.06 |