Optical Properties and Reorientation of M Centers in NaF

Abstract

Abstract The reorientation efficiency of M centers in NaF is found to be proportional to the M + concentration, suggesting that M centers reorient via an M + mechanism, as in KCl. In this mechanism light is first absorbed in the higher transitions of the M centers causing them to ionize, and then in the higher transitions of the M + centers causing them to reorient. The higher transitions of both the M and the M + center are identified. In addition, a new absorption band at 516 nm giving rise to emission at 680 nm, seen in lithium‐doped samples, is tentatively identified as due to the lithium M A center.