Abstract

We report on the generation of radiation of high brightness in gas lasers by making use of phase-conjugation (PC) devices. We investigate conditions for obtaining beams of quasidiffraction quality in lasers with PC of radiation at SBS. Experiments have been conducted on a photodissociation iodine laser operating in a free-running mode. The pulse duration is ~4 µs, the lasing energy and the SBS pumping energies are ~300 J and ~60 J, respectively. It has been shown that in high-power pump conditions PC is not ideal and at SBS we observe generation of noise components of angular spectrum, the intensity of which reaches ~10³ of a PC component. Aiming to increase the PC quality, injection of radiation into the SBS cell is achieved through the use of a kinoform array of binary Fresnel lenses. Selection of the PC component of radiation by methods of linear optics allows one to increase the radiation brightness of a laser with a SBS mirror more than five-fold. The Strehl number for a total beam ~100 mm in diameter is 0.3. As a result of the laser system optimization we have obtained a beam divergence of 3 × 10^-5 rad.

© 1992 Optical Society of America