Wave-front tilt sensor with two quadrant detectors and its application to a laser beam pointing system

Abstract

A method that uses two quadrant detectors (QDs) for sensing wave-front tilt is described. The detectors are set at the front and back of the focal plane of the focusing optics. When the intensity distribution at the aperture of a telescope is not uniform because of atmospheric turbulence, the wave-front tilt can be measured more accurately with our two-QD method than with a conventional single-focal-plane QD. We proved this method to be effective by using it for fixed-star observation. Application of the method to a ground-to-satellite laser beam pointing system showed that it increases the intensity of the laser beam that is transmitted to a satellite.