Spectroscopic properties of Eu:Bi4Ge3O12 single crystal grown by the micro-pulling-down method

Abstract

Eu3+-doped Bi4Ge3O12 (BGO) single crystal with the size of Ø2 × 83 mm3 was successfully grown by the micro-pulling-down method. The absorption cross section, emission cross section and Judd–Ofelt analysis of Eu:Bi4Ge3O12 (Eu:BGO) were reported for the first time. The absorption cross-section is 1.03 × 10−20 cm2 with full-width at half-maximum of 3.1 nm at around 393 nm. The spectroscopic intensity parameter Ωt (t = 2,4,6), radiative transition probabilities, branching ratios and radiative lifetime were obtained, respectively. Furthermore, the stimulated emission cross-section centered at 611 nm was calculated to be 6.32 × 10−21 cm2. The fluorescence lifetime of 5D0 level was obtained to be 1.51 ms. The results indicate that Eu: BGO single crystal could be a potential laser host in the visible range.