Lasing in slurry-like active medium on LiF:F₂ microparticles

Active media composed of the particles of solid-state laser-active material immersed in the liquid are the subject of research since this approach can provide new solutions to the problem of heat removal from the laser medium. Investigation of the active medium on microparticles of LiF crystal with F₂ color centers is presented. The technique of the preparation and characterization of the index-matched slurry-like mixture was developed. Powders of LiF crystal particles with F₂ color centers with size from 50 to 1000 μm immersed in various liquids and their mixtures were tested. Laser radiation of a compact cavity containing two flat dichroic mirrors and a glass cuvette with the LiF:F₂ slurry with grain size of 500 ÷ 1000 μm and the mixture of heptane and vaseline oil was obtained under Coumarin 120 dye laser pumping. The pulses of the laser radiation with the beam divergence of 2 ÷ 5 mrad at the wavelength of about 680 nm, duration of 10 ns and energy of 83 μJ were obtained under pulsed pumping with the energy of 1.34 mJ. The real and slope efficiencies of the LiF:F₂ slurry laser reached 6.2% and 12.9% correspondingly. (paper)