Optically controlled adaptive mirror

We report on an adaptive mirror system that allows generating thermo-optically controlled wavefront corrections. The influence of the wavefront is based on the thermal dependence of the refractive index in a thin active layer. The thermal pattern in the active layer is generated by irradiation with a diode laser emitting at 805 nm. The active layer consists of a diluted aqueous solution of NdCl3. A Michelson interferometer is used to measure the wavefront distortions. A phase shift of 6pi with a lateral resolution of better than 1 mm and a temporal rise/fall time of a few seconds can be achieved with an absorbed power of only 150 mW at an intensity of about 10 W/cm(2).