Comparative study of Ho:Y2O3 and Ho:Y3Al5O12 transparent ceramics produced from laser-ablated nanoparticles

Ho:Y2O3 and Ho:Y3Al5O12 transparent ceramics are fabricated by vacuum sintering at 1780 degrees C for 20 h from laser-ablated nanopowders (Ho:Y2O3 and Ho:Y2O3 + Al2O3) using ZrO2 and TEOS as sintering aids, respectively. The sesquioxide ceramic exhibits smaller grain size (similar to 5.4 mu m), smaller content of pores (down to 6 ppm) and higher optical transmission (up to 82.2% at similar to 1 mu m) than the garnet one. A detailed comparative spectroscopic study of the two ceramics is performed. For the I-5(7) -> I-5(8) Ho3+ transition, the maximum stimulated-emission cross-sections and the luminescence lifetimes are sigma(SE) = 0.57 x 10(-20) cm(2) at 2087.1 nm and tau(lum) = 10.92 ms (for the Ho:Y2O3 ceramic) and sigma(SE) = 1.70 x 10(-20) cm(2) at 2090.8 nm and tau(lum) = 7.04 ms (for the Ho:Y3Al5O12 one) The rates of multiphonon relaxation are determined for both ceramics. For the Ho:Y2O3 ceramic, they do not exceed those for single-crystals. The crystal-field splitting of Ho3+ multiplets (I-5(7) and I-5(8)) is determined at 12 K and analyzed using the barycenter plot. Due to its broadband emission properties, the Ho:Y2O3 ceramic is suitable for mode-locked lasers emitting above 2 mu m.

Automated summary

Ho:Y2O3 and Ho:Y3Al5O12 transparent ceramics were fabricated by vacuum sintering, showing different grain size, pore content, and optical transmission. Comparative spectroscopic study revealed their potential for different types of lasers based on their emission properties.