Population of excited levels in YLF:Er crystals under CW laser diode pumping

Summary form only given. The main goal of our work was to investigate, both by theoretical and experimental methods, the influence of interionic cross relaxation processes (upconversion, selfquenching) on concentration dependences of inverse population of laser levels in LiYF/sub 4/:Er laser crystals under CW laser-diode pumping with different pump power densities.