Comparative experimental investigation of thermal loading in continuous-wave cr4+: forsterite lasers

Abstract

Results of a detailed experimental study aimed at reducing the thermal loading effects in room-temperature continuous-wave Cr4+:forsterite lasers are presented. By using a Nd:YAG pump laser operated at 1.06 mu m, the effect of the absorption coefficient and crystal cross-sectional area on the power performance of three crystals was compared between 12 and 36 degrees C. Experiments indicated that a low differential absorption coefficient significantly reduces the pump-induced thermal effects and cavity losses that would otherwise give rise to inefficient operation and increased temperature sensitivity. In particular, a Cr4+:forsterite crystal with an absorption coefficient of 0.57 cm(-1) yielded as much as 900 mW of output power at 1.26 mu m and a crystal temperature of 15 degrees C with an incident pump power of only 7.6 W. To the author's knowledge, the demonstrated slope efficiency of 30% represents the highest continuous-wave power performance reported to date from this laser system at elevated temperatures. (C) 1998 Optical Society of America.