The spectral and lasing properties of Li-Nd phosphate glass

A procedure for preparing Li-Nd phosphate glass of a composition similar to that of mixed metaphosphate is described. The glass is characterized by high physicochemical stability, is not affected by atmospheric humidity, and has a refractive index of 1.55. Samples of this glass were used for spectroscopic and lasing studies. A portion of the absorption spectrum at 700 to 910 microns is presented. The values of the absorption coefficients were approximately 15 times the values of commercial silicate glasses. Using a Raman laser for pumping a 2.26-mm thick sample placed in the focus of a spherical mirror and a lens, a lasing threshold of 15 mJ (energy of radiation incident on the sample) was obtained. The lasing spectrum width was 40 A. The wavelength at the line center was 1.055 microns. The lasing spectrum was composed of equidistant lines spaced 1.6 A apart.