Studies on a novel Ho3+:KBGM crystal toward the ∼2 μm laser applications

Abstract

A Ho3+:KBGM crystal with good quality and large size was successfully grown via TSSG method. The crystal’s structure, ambient-temperature polarized absorption and emission spectra and fluorescence lifetime were studied. The J-O theory was adopted to analyze the absorption spectra and results show that crystal exhibits relatively large intensity parameters Ω2 and spectroscopic quality factor which is up to 3.12. At 453 nm, the absorption band is the strongest, and the corresponding cross-sections are 21.94 × 10–20 cm2, 26.66 × 10–20 cm2 and 18.56 × 10–20 cm2 for the -X, -Y and -Z polarizations, respectively. The emission spectra also demonstrate the broad and strong emission band at 2030 nm. The FWHMs and cross-sections are 74 nm, 0.37 × 10−20 cm2, 50 nm, 0.68 × 10−20 cm2, and 49 nm 0.52 × 10−20 cm2 for the three polarizations, respectively. In addition, the crystal has a superior quantum efficiency which is as high as 97.1%. Taking all the analyses into account, it is reasonable to assert that the Ho3+:KBGM crystal an ideal candidate for ∼2 µm laser applications in many areas.