Analysis on energy transfer process of Ho3+ doped fluoroaluminate glass sensitized by Yb3+ for mid-infrared 2.85 μm emission

This work reports the mid-infrared emission properties around 2.85 mu m in a Yb3+/Ho3+ codoped fluoroaluminate glass. This fluoroaluminate glass shows a good thermal stability and high transmittance around 3 mu m. The mid-infrared emission characteristics and energy transfer mechanism upon the excitation of the conventional 980 nm laser diode have been investigated. The prepared glass possesses higher spontaneous transition probability (31.77 s(-1)) along with the larger calculated emission cross section (1.91 x 10(-20) cm(2)) corresponding to the laser transition of Ho3+:I-5(6)-> I-5(7). Besides, the upconversion, 1.2 mu m and 2 mu m fluorescence spectra were measured to understand mid-infrared emission behavior together with decay curves of Ho3+:I-5(6) level. Moreover, energy transfer microparameters between Yb3+ and Ho3+ were calculated and discussed based on Dexter's model. Hence, the advantageous spectroscopic characteristics of Yb3+/Ho3+ codoped fluoroaluminate glass as well as the good thermal property indicate that this kind of glass is an attractive host for developing mid-infrared solid state laser. (C) 2014 Elsevier Ltd. All rights reserved.