Determination of laser parameters of ytterbium-doped oxide crystalline materials

Abstract

Spectroscopic and laser properties at ∼1 µm of seven new ytterbium-doped crystalline materials—silicates ${\mathrm{Y}}_2{\mathrm{SiO}}_5,$ ${\mathrm{Ca}}_2{\mathrm{Al}}_2{\mathrm{SiO}}_7,$ ${\mathrm{SrY}}_4({\mathrm{SiO}}_4{)}_3\mathrm{O},$ borates ${\mathrm{Ca}}_3{\mathrm{Y}}_2({\mathrm{BO}}_3{)}_4,$ ${\mathrm{Ca}}_3{\mathrm{Gd}}_2({\mathrm{BO}}_3{)}_4,$ ${\mathrm{Sr}}_3\mathrm{Y}({\mathrm{BO}}_3{)}_3,$ and ${\mathrm{Ba}}_3\mathrm{Lu}({\mathrm{BO}}_3{)}_3$— are investigated. Absorption and emission cross sections are strongly dependent on the crystalline host. Good agreement is obtained between emission cross sections calculated by the reciprocity method and by the Füchtbauer–Ladenburg method. The wavelength dependence of the gain cross sections are also determined. Except for ${\mathrm{Ba}}_3\mathrm{Lu}({\mathrm{BO}}_3{)}_3,$ which is of poor crystalline quality, laser oscillations in a plano-concave cavity are obtained for all the presented hosts. From optical spectroscopy and laser results, large tunability of the emission is expected for these materials. Slope efficiencies are in the range 40%–60% with very low threshold values.