Laser action in chromium-activated forsterite for near-infrared excitation: Is Cr4+ the lasing ion?

Abstract

Room-temperature pulsed laser action has been obtained in chromium-activated forsterite (Cr:Mg2SiO4) for excitation of the near-infrared absorption band of the system by the 1064 nm radiation from a Nd:YAG laser. The characteristics of laser emission are similar to those observed for 532 nm pumping. It is suggested that the laser action is due to a ‘‘center’’ other than the trivalent chromium (Cr3+), presumably the tetravalent chromium (Cr4+).