Growth and optical properties of a Sm3+, Eu3+ co-doped La2CaB10O19 crystal

Abstract

Due to the excellent spectral properties, Eu3+-doped La2CaB10O19 (Eu3+:LCB) single crystals have shown promising prospect as a medium for laser radiation in the visible region. However, the weak absorption and emission intensities of Eu3+:LCB single crystals limit their laser application. Here, a Sm3+, Eu3+ co-doped La2CaB10O19 (Sm3+, Eu3+:LCB) crystal is grown to improve its optical performance. The intensity parameters, spontaneous transition probability, radiation lifetime and fluorescence branch ratio of the Sm3+, Eu3+:LCB crystal are studied with the Judd–Ofelt theory. Compared with an Eu3+-doped La2CaB10O19 (Eu3+:LCB) crystal, the Sm3+, Eu3+:LCB crystal exhibits higher absorption intensities and optical transition line strengths. Based on emission spectra, an energy transfer process from Sm3+ to Eu3+ ions in the Sm3+, Eu3+:LCB crystal is supposed. Fluorescence lifetimes for the Sm3+ and Sm3+→Eu3+ energy transfer process are calculated to be 1.698 ms and 3.648 ms, and energy transfer efficiency from Sm3+ to Eu3+ ions is calculated to be 13.7%. Compared with the Eu3+:LCB crystal, the emission intensity of the Sm3+, Eu3+:LCB crystal is doubled. Our work shows that the absorption and emission intensities of Eu3+:LCB crystals are significantly enhanced by co-doping with Sm3+ ions, which is conducive to their application for visible lasers.