37-element adaptive optics experimental system and turbulence compensation experiments

A 37 element adaptive optics system has been built in the Institute of Optics and Electronics for experimental research of atmospheric effect compensation. In this system a 37 subaperture Shack-Hartmann sensor with frame rate 380 Hz is used as wavefront sensor, a 37/55 element deformable mirror and a fast steering mirror as wavefront correctors, a digital signal processor with peak operation speed 100 Mops as wavefront processor and controller, and 39 channels of high voltage amplifier for controlling the wavefront correctors. This system has been integrated with a turbulence cell developed by the Anhui Institute of Optics and Fine Mechanics and experiments for compensating for wavefront errors induced by the turbulence of the cell with different strength have been conducted. Another Shack- Hartmann wavefront sensor is used for measuring the strength of turbulence. The integrated probability density functions of both the coherence length r0 and the Strehl ratio of S of the focused spot are used to describe the strength of turbulence and the sharpness of focused spots with and without correction. In this paper the adaptive optics system and the experimental results are briefly reported.