Abstract

We describe the use of a grating disperser to allow effective phase conjugation of broadband radiation with stimulated Brillouin scattering. With conventional configurations the bandwidth of the pump radiation is restricted because the Brillouin reflectivity decreases when the pump bandwidth becomes wider than the Brillouin linewidth and the conjugate fidelity decreases when the coherence length becomes shorter than the effective interaction length. With our technique the pump beam is focused into a laterally extended focal region, each element of which has effectively narrowband radiation. As long as these narrowband focal-region elements carry sufficient spatial information each will provide a conjugate of the pump wave at its appropriate wavelength. Because the return beam from the Brillouin cell is a conjugate of the incoming beam it will reconstruct off the grating to form a conjugate of the beam as a whole, rather than a beam with double the dispersion. We demonstrate the performance of this technique in correcting phase aberrations using radiation at 353 nm from a XeF laser and SBS in n-hexane. Comparisons are made of performance with and without the grating disperser and results are compared with theory. In addition we present studies of the effects of various types and degrees of aberration and various amounts of grating dispersion.

© 1986 Optical Society of America