I present a model devoted to linking the properties of a quasi-three-level laser crystal to microscopic parameters. The role of the radiative diffusion is taken into account with a sample-size-dependent parameter, including the total internal reflections, allowing both radiative and nonradiative diffusions to be treated equally. The radiation self-trapping aspect is quantified with the number η′<sub>imp</sub> of imprisoned photons engendered by one absorbed pump photon. The losses toward the traps that are not always well known are described with the dipole-dipole interaction, giving a microscopic interpretation of the heat dispensed in the sample from the pump. One prediction is that the excited-state decay of the donor subsystem is exponential, in agreement with experiment. The main experimental data, which are the excited-state intrinsic and extrinsic lifetimes τ and τ′ and the extrinsic fractional thermal loading ξ′, can be calculated by adjusting a small number of parameters. This number can be reduced by use of spectroscopy. I have shown that this model can be applied with a reasonable success to Yb3+-doped Y3Al5O12.
© 2006 Optical Society of America
Original Manuscript: October 14, 2005
Revised Manuscript: May 18, 2006
Manuscript Accepted: June 1, 2006
Alain Brenier, "Excited-state dynamics including radiative diffusion in quasi-three-level laser crystals: application to Yb3+-doped Y3Al5O12," J. Opt. Soc. Am. B 23, 2209-2216 (2006)