How good is the initial figure of OKO deformable mirrors?

The surface quality of all OKO mirrors is similar to any other solid reflective optics produced by leading manufacturers. It is good enough to work with very low scattering in the whole visible spectrum.

The initial figure of MMDM is flat with RMS deviation from the nearest reference plane better than 400nm. OKO mirror with 37 channels and a diameter of 15mm will have less than 1 fringe of astigmatism averaged over a number of devices. Larger MMDM have 8 adjustment screws that allow to set the initial figure of the mirror. The initial optical quality is very good.

The initial figure of PDM is flat with RMS deviation from the nearest sphere better than 500 nm. The initial surface may have some irregularity due to random hysteresis state of different actuators. These irregularities are always formed as combinations of the mirror influence functions and they are completely correctable by the mirror.