Abstract

The energy loss lacking and wide spectral band method of one-way dynamic correction for phase distortions, based on the use of the optically addressed liquid crystal spatial phase light modulator (OA LC SLM) in negative optical feedback¹ is very promising Probe beam passes through the distorter and through the LC layer of SLM Then it is collinear combined with reference beam, and the resulting interference pattern controls phase retardation in LC SLM. Negative feedback dynamics results in realisation of the corrector, adding to the distorter influence Practical implementation of the method was blocked by the 2π-problem — indeterminism of phase reconstruction from intensity distribution For the extended range of distortions scale the corrector breaks into domains, and can be used only for narrow spectral band or, without breaking, for small-scale distortions. Recently² we have solved the problem by the application of the dynamic holographic converter of distortions scale The talk describes the improved schematics of the corrector record. The distortions are probed by two collinear beams with wavelengths λ and λ′. Distorted probe beam at λ′ writes in another OA LC SLM the thin dynamic hologram, which is reconstructed by the distorted probe beam at λ. Reconstructed reference wave has residual distortions of the scale |λ − λ′|/λ′. Its interference pattern with nondistorted beam reveals much wider range of monotonous variation. OA LC SLM, controlled by such pattern can be used for wide spectral band correction for large scale (say, several or several dozen λ) distortions. System performance analysis, key technologies involved and performance simulation will be discussed in the talk.

© 1998 IEEE