<title>Recent results for visible Rayleigh guide-star atmospheric experiments</title>

Abstract

We report on the operation and performance of an integrated 1 m adaptive optics system for compensation of atmospheric distortion of optical wavefronts. Both visible artificial laser guide stars (doubled Nd:Yag laser with wavelength of 0.532 rim) and natural stars can be used as sources for reference wavefronts. A shearing interferometer which uses a narrow optical bandwidth and has 500 subapertures is employed to sense wavefront distortion. These measurements are used to compute a conjugate wavefront to the distorted input light. The computed conjugate is then imprinted on a deformable mirror which consists of 500 square mirror segments. The effectiveness of the compensation is determined from a measured PSF of the system. Both indoor benchtop and atmospheric experiments are under way to test the performance of the integrated system.The results of these initial tests are very promising, yielding short-exposure images at 0.532 microns which contain discernible energy at the diffraction limit of 0. 1 arcsec.

<title>Adaptive (immunized) speckle interferometry concept</title>

“…During the subsequent decentralized estimation of OTF and of sought-for O(r) , these signals can be asynchronously and semiindependently processed with exchange of information (intercorrection) in part of current estimates H[s] and HR [8] . Signals emitted by RS and object are purposely selected and are recorded separately.…”