Influence of energy-transfer upconversion and excited-state absorption on a high power Nd:YVO4 laser at 134 μm

Abstract

A self-consistent theoretical model considering both energy-transfer upconversion (ETU) and excited-state absorption (ESA) effects, as well as the couplings among the temperature distribution in the laser crystal, the thermal fractional loading, the upper state population involved in the ETU and ESA effects, the laser output and other temperature-dependent parameters, was developed to simulate the behaviors of diode-end-pumped continuous-wave (CW) single-transverse-mode (TEM00) lasers. Based on the theoretical and experimental investigations of the influences of ETU and ESA effects on laser performance, a high power CW TEM00 Nd:YVO4 1.34 μm laser dual-end pumped at 880 nm was achieved with a maximum output power of 16 W. The measured laser beam quality was M2x = M2y = 1.17 and the stability of the laser output was better than ± 0.9% in a given four hours. The theoretical predictions considering both ETU and ESA effects are in good agreement with experimental results.