efficient random laser for differentiated control of light gain and diffusion

摘要

Summary of the Patent for Invention “RANDOM LASER EFFICIENT BY DIFFERENTIATED CONTROL OF GAIN AND LIGHT DIFFUSION” A new strategy is developed to increase the efficiency of a random laser, which consists in separately controlling the diffusion of light from absorption and gain in the system. Smaller particles are trapped between large particles to serve as centers of absorption and gain, while large particles mainly control the diffusion of light in the sample. In addition to their optical properties (greater absorption and gain), these pockets are pumped from all sides and in any direction so that the penetration or diffusion of the pumping light into the pockets is optimized and the pumping power density is maximized. An efficiency greater than 50% is achieved, optimizing the diffusion and absorption of pumping photons in a sample of polydispersed powder, composed of smaller particles among the largest, of a crushed and sieved crystal of 1.33 mol% Nd: YVO4 with size particle average of 54 micrometers. The smaller particles, which are trapped between the larger particles in pockets, are responsible for a 15% increase in the number of dispersion events, increasing the density of pumping power in these pockets. In direct comparison between polydispersed and monodispersed samples, the effect of the smaller particles causes a 3.1x increase in terms of total output power. This strategy can be extended or extrapolated to other systems where the regions of greatest absorption and gain with the shortest effective transport length (greatest spreading force) can be made of a different material to that which governs the diffusion of light.