High-optical conversion efficiency and high-beam quality using self-consistent thermal effect

Spatial distributions of pump and oscillating beams are altered by thermal effect in high-power end-pumped solid-state lasers. This study revealed a specific pump power range within which the pump beam and fundamental-mode oscillating beam almost completely overlap in the Nd: YAG gain medium under thermal effect, which results in high optical-optical conversion efficiency and high beam quality. When pumping power ranges from 105 W to 115 W, the output power and the optical-optical conversion efficiency are higher than 42 W and 38%, respectively, with beam quality less than 2.3. The maximum output power and optical-optical conversion efficiency are 45 W and 42.1%, respectively, with M_x ²=2.14 (M_y²=2.32) when the pump power is 109 W. Outside of this range, the values rapidly deteriorate.