Spherical aberration correction system using an adaptive optics deformable mirror

A deformable membrane mirror is often used in closed loop adaptive optics systems to correct for aberrations and improve image quality. In certain applications, the correction of only one type of aberration is sufficient, the calibration procedure of the mirror can be simplified and the control scheme can be reduced to a fast feed forward system. For these cases we developed a procedure that is easy to implement, accurate and delivers a large correction range. An application example is the writing and readout of three-dimensional optical memory. Here the spherical aberration component is dominant and can be inferred from the focussing depth. We describe the principle of the new calibration and feed forward control scheme and give experimental results.