A computational model for operation of co-doped Tm,Ho solid-state lasers is developed coupling (i) 8-level rate equations with (ii) TEM00 laser beam distribution, and (iii) complex heat dissipation model. Simulations done for Q-switched ≈0.1 J giant pulse generation by Tm,Ho:YLF laser show that ≈43% of the 785 nm light diode side-pumped energy is directly transformed into the heat inside the crystal, whereas ≈45% is the spontaneously emitted radiation from 3F4, 5I7 , 3H4 and 3H5 levels. In water-cooled operation this radiation is absorbed inside the thermal boundary layer where the heat transfer is dominated by heat conduction. In high-power operation the resulting temperature increase is shown to lead to (i) significant decrease in giant pulse energy and (ii) thermal lensing.
© 2007 Optical Society of AmericaPDF Article