Investigation of explosively pumped photo-dissociation iodine laser with phase conjugation of super-high quality

Summary form only given results of simulations and experiments on a high-power double-pass explosively pumped photo-dissociation iodine laser (EPDL) with phase conjugation (PC) are presented. Laser system consists of master oscillator, two exploding amplifiers at working mixture 25 Torr C₃F₇I+125 Torr Xe and amplifier aperture 15 cm, and SBS mirror. SBS mirror consists of an angular selector of Stokes radiation, an ordered raster of small diffraction lenses, a main focusing lens, and a SBS cell. The calculation model and computer code package take into account actual three-dimensionality of space, nonsteady-state and transient effects at SBS and laser amplifications. An optimal configuration of the SBS mirror is used that possesses unique properties if compared to the current SBS mirrors. It stably gives a nearly ideal quality of PC at any reflection coefficient that has been experimentally confirmed. A good agreement of calculated results with experimental data has been shown in energy, time dependence of power and Strehl number of EPDL radiation. The EPDL has output energy of about 400 J and brightness of about 10¹²J/ster. It has been found that under rising input signal of the master oscillator, the brightness of the EPDL increases whereas the full energy varies relatively slightly. It has been shown that parasitic reflections of laser radiation from the elements of the optical scheme with a coefficient exceeding 10^-7 considerably decrease the axial brightness of output radiation. In order to reduce the harmful effect of parasitic reflections on brightness, the distance between the amplifiers should be increased.