M. Hattori and S. Komatsu: Real-time Adaptive Optics with a Twisted Nematic Liquid Crystal Light Modulator Controlled by the Wave Front Reconstruction Sensor, Opt. Rev., Vol. 9 (2002) 126-131.

We propose adaptive optics constructed with a new principle. In this syatem, numerical phase reconstruction algorithm is incorporated with the Hartmann wave front sensor and the phase compensator is driven to the conjugate of the input phase distortion at each step. The computer simulation shows a sufficient robustness and swiftness of the wave front reconstruction sensor. Then, the experimental system is configured putting special emphasis on the simplicity and feasibility of the system. A small 2-dimensional grid mask is used in the Hasrtmann sensor, and a twisted nematic phase modulator with a response time of 30 ms is used as the phase compensator. The control system has a simple open loop setup using a phase reconstruction algorithm. This experimental system was effective not only for static phase distorion, but also for the dynamic phase perturbation induced by a thermal convection.