Solid active media for tunable lasers based on dye-doped polyurethanes

This article is devoted to a brief review of the main results of the research cycle aimed at developing solid active media based on dye-activated polyurethane compounds. The ultimate goal of these studies is the creation of solid-state active elements that make it possible to realize a wide-band solid-state dye laser (SSDL), which emits frequency-tunable radiation with a microsecond pulse duration. The problem has been solved mainly by experimental methods. At the same time, the studies carried out included a full range of works from the production of samples of solid-state active media to the study of the lasing characteristics of the active elements created. In the course of the work, lasents based on industrial polyurethanes of various grades activated with the Rhodamin 6G, Sulforhodamine 101, Oxazin 17, and Oxazin 1 dye have been created, and their spectral-luminescent characteristics have been studied. The experimental samples of laser matrices are made. The optical properties of the created media are studied, and the influence of the technique of making samples on the nature of possible distortions of their optical homogeneity is determined. The emission ability of polyurethane matrices is studied. With transverse monochromatic excitation, laser emission on polyurethane matrices has been obtained with an efficiency of 12 to 26% and energies from 23 to 127 mJ. Radiation resistance and possible service life of polyurethane media are investigated. The thermo-optical properties of polyurethane active media and their effect on the directivity of SSDL radiation is studied. The effect of induced birefringence, which occurs under conditions of asymmetric pumping of microsecond duration, is observed. It is found that under such conditions, polyurethane active elements emit polarized radiation even when excited by depolarized light. The possibilities of narrowing and tuning the emission spectrum of polyurethane matrices in dispersive resonators with angular and amplitude types of selection have been investigated. The laboratory model of a tunable SSDL with replaceable polyurethane laser elements generating a pulsed radiation of a microsecond duration in the spectral range of 565...700 nm is created and tested. The results of the performed studies allow us to conclude that industrial polyurethane compounds can be successfully used as solid media for active elements of SSDL. ©2019 by Begell House, Inc.