Self-heating of a YAG:Nd3+ crystal in an illumination enclosure of a cw laser

A calculation is reported of the temperature of an active element in an illumination enclosure containing a cw YAG:Nd³⁺ laser. It is shown that, depending on the absorption coefficient δ of the active element at the 1.06 μ wavelength, quenching of stimulated emission may result in an increase (in the case of low values of δ) or a reduction in the temperature of the active element. A calculation, carried out allowing for the self-heating of the active element by stimulated radiation and absorption of part of the spontaneous radiation, demonstrates that the heat balance in the active element inside a laser illumination enclosure is attained when the quantum efficiency of the luminescence originating from the ⁴F_3/2 level is close to unity. The calculations are supported by experimental data.