Effective 3.5 μm emission of Er3+ ions in fluoroindate glass with improved thermal stability

Abstract

The development of effective 3.5 μm laser derived from a gain medium doped with Er3+ ions is of great significance for research on mid-infrared (MIR) lasers. Existing 3.5 μm laser materials are unable to exhibit both stable thermal and excellent MIR optical properties simultaneously. In this study, a system of fluoroindate glasses was prepared and analyzed through differential scanning calorimetry (DSC) and Raman spectra. The thermal stability was improved by regulating the Al(PO3)3 content with the value of ΔT up to 110 °C. Notably, a maximum Er3+ concentration up to 11 mol% can be contained in this transparent high-optical-quality glass with an effective 3.5 μm emission. In addition, the energy transfer mechanisms and theoretical calculation results of the absorption and emission coefficients also verify the outstanding 3.5 μm fluorescence of Er3+ in the proposed fluoroindate glass, which can provide a new and attractive choice for 3.5 μm laser gain media.