Ultraviolet-Induced Transient and Stable Color Centers in Self-Q-Switching Laser Glass

Abstract

The optical absorption spectrum of ultraviolet- (uv-) induced room-temperature stable color centers and the uv spectrum for their generation in a laser self-Q-switching glass were obtained. The optical absorption spectrum is similar to that for x-ray-irradiated silicate glasses of simpler composition. The uv generation spectrum was found to consist of a narrow Gaussian line of width 2250 cm−1 with peak at 45 800 cm−1. The optical absorption spectrum of the uv-induced transient color centers was also obtained and appears to consist of the superposition of a broad asymmetric absorption band peaked near 740 nm and a Gaussian-shaped annihilation band peaked near 674 nm. The lifetime of the 740-nm band was found to be about 200 msec and that of the 674-nm band about 400 msec. The 740-nm transient absorption band is identified with the E1,2− band which Mackey, Smith, and Halperin attribute to a trapped electron polaron. The line shape of this transient absorption is interpreted in terms of a large-polaron strong-coupling model from which various properties are inferred. The transient annihilation band at 674 nm is identified with the temporary bleaching of a room-temperature stable trapped-hole center. A model is suggested for the production of both stable and transient color centers.