Influence of the thermal effect on the TEM00 mode output power of a laser-diode side-pumped solid-state laser

A fraction of pump power has been converted to TEM, mode laser power for a side-pumped solid-state laser by use of a space-dependent rate equation. We investigated the pump-to-mode (TEM00) ratio when scaling laser-diode side- pumped solid-state lasers to high-power levels by including the thermal eff ect in the space-dependent rate equation. Based on the assumption that Gaus sian pump power is the same at any cross section of a laser rod, we resolve d the output power with a space-dependent rate equation; temperature distri bution in the laser rod was obtained; the optical path difference distribut ion was derived, and we estimated the diffraction losses that result from t hermally induced spherical aberration by use of the Strehl intensity ratio. We determined that thermally induced diffraction losses are strongly depen dent on pump power and on the pump-to-mode ratio. (C) 2000 Optical Society of America OCIS codes: 140.3480, 140.3580, 140.4780.