Compact active high-resolution imaging system

Abstract

High-resolution telescope systems used for observational tasks require sufficiently large apertures to enhance the spatial resolution. Due to the propagation through turbulent layers of the atmosphere the distorted wavefront implicates a broadening of the imaged spot and hence a loss in optical resolution. The improvement in visual resolution by applying adaptive optics has been successfully demonstrated in a mobile telescope platform. To compensate for the effects of atmospheric turbulence, a closed-loop system was developed with a bandwidth of up to 600 Hz capable to achieve a wavefront correction with a residual wavefront deformation of 50 nm RMS. A reference signal which is probing the wavefront distortion is realized with the help of a coherent laser beam emanating from the object. The developed adaptive optical system is capable of compensating phase distortions in a conjugated plane with time constants of 30 ms. Turbulence was artificially induced along the optical path by a turbulence generator. Measurements of MTF values and Strehl ratio will be presented.