Broadened and Enhanced Mir Emission in Yb3+/Er3+/Dy3+ Triply-Doped Cayalo4 Crystal

Abstract

Yb3+/Er3+/Dy3+ triply-doped CaYAlO4 single crystal was successfully grown to obtain the broadened and enhanced 3 μm MIR emission. The structure characters were studied by XRD measurement. The optical properties and energy transfer mechanisms between Yb3+, Er3+, and Dy3+ were investigated according to the measured absorption spectra, emission spectra and fluorescence decay curves. The absorption spectra show that the triply-doped crystal could be effective pumped by 980 nm due to the introduced of Yb3+ and Er3+. In comparison with Dy3+ singly-doped CaYAlO4 crystal, a broadened and enhanced ~3 μm MIR emission with a full width at half maximum (FWHM) of 286 nm was obtained due to the fact that there exists effective energy transfer process from Yb3+ and Er3+ to Dy3+. For Yb3+, it serves as an effective sensitized ion. For Er3+, it could be not only used as an effective sensitized ion, but also as 2.7 μm MIR emission center. For Dy3+, on the one hand, it can serve as a deactivating ion to solve the self-termination bottleneck effect of Er3+, and more importantly, as an emission center to achieve 3 μm emission. The comprehensive effect is to obtain enhanced and broadened MIR emission in the triply-doped crystal. In addition, the corresponding energy transfer efficiency from Yb3+: 2F5/2 to Dy3+: 6H5/2 is as high as 90%. Hence, the Yb3+/Er3+/Dy3+: CaYAlO4 crystal could be used as promising medium for mid-infrared broadband tunable laser applications.

Keywords: Yb3+/Er3+/Dy3+: CaYAlO4, Crystal structure, Optical properties, Energy transfer, Mid-infrared laser