Phase conjugation method in adaptive light beam shaping systems

Abstract

The results obtained permit making certain deductions about the operation of systems using a phase conjugation algorithm. If the object surface possesses a multihighlight structure, then system operation depends substantially on the relationship between the diffraction-limited size of the spot and the spacing between the highlights. The stationary field distribution on an object is ordinarily the result of multiple interference of the fields from individual highlights, and depends on the initial focusing conditions. In the presence of a highlight with maximal brightness the adaptive system focuses the radiation on this highlight independently of the initial condition with a characteristic convergence time dependent on the difference in the highlight brightnesses. Weak random phase modulation of the highlights has practically no influence on adaptation in the system. Nonatationary thermal blooming substantially reduces the efficiency of a phase-conjugate correction. Beam wandering, a periodic change in its parameters, is possible under a strong phase-conjugate correction. Beam wandering, a periodic change in its parameters, is possible under a strong nonlinearity.