SENSORS FOR ADAPTIVE OPTICS.

Adaptive optics providing automatic compensation for wavefront deformation in systems which employ highpower lasers in communication, energy and military applications are discussed. The basic requirements for atomspheric wavefront correction include speed of 100 to 1,000 hertz and spatial resolution of about 300 points for a one-square-meter aperture, with at least linear interpolation of phase between the resolution points. The corrector must provide a constant optical-path difference for all wavelengths, rather than a constant phase correction, with correction amplitude 1 to 2 micrometers plus over-all tilt, and root-mean-square accuracy within 1/20 wave. These requirements can be met with a monolithic piezoelectric corrector. The sensor must meet the same requirements for speed and resolution as the corrector. To provide input to the corrector, the sensor also must observe the same wavefront disturbance experienced by the light coming from the object being viewed.