Highly-doped YAG:Sm3+ transparent ceramics: Effect of Sm3+ ions concentration

Abstract

YAG:Sm3+ (3–15 at.%) transparent ceramics, a promising cladding material for suppressors of parasitic oscillations at 1064 nm of YAG:Nd3+ lasers, have been prepared by solid-state reactive sintering at 1725 °C. The effect of samarium ions concentration on the microstructure and optical properties of YAG:Sm3+ sintered ceramics was studied for the first time. The solubility limit of samarium ions in the garnet matrix was found to lie within the range of 9–11 at.%. The spectroscopic characterization of YAG:Sm3+ (3–15 at.%) ceramic samples showed that the absorption coefficients corresponding to Sm3+ ions transitions increased linearly with increasing Sm3+ doping. Also, the increase in the concentration of Sm3+ ions contributes to the increase in the intensities of the satellites, leading to the broadening of the main spectral lines and implicitly to the increase of the absorption coefficient around 1064 nm. It was shown that YAG:Sm3+ ceramics doped with 9 at.% Sm3+ ions possess optical losses of 0.07 cm−1 at 808 nm and an optical absorption coefficient of 4.45 cm−1 at 1064 nm. The concentration dependence of the 4G5/2 level decay confirmed that the luminescence extinction is due to the energy transfer between the Sm3+ ions through cross-relaxation processes. All these results show that highly-doped YAG:Sm3+ (9 at.%) ceramics could be the best candidate for parasitic oscillation suppression in high-power YAG:Nd3+ lasers at 1064 nm.