Effect of OH~- Content on Mid-infrared Emission Properties in Er~(3+)-doped Ge-Ga-S-CsI Glasses

A series of Er3+-doped chalcogenide glasses based on Ge-Ga-S-CsI system were prepared by melt-quenching technique with distillation processing.Properties including refractive index,infrared transmission spectra,2.85μm mid-infrared emission spectra and fluorescence lifetime under 800 nm laser excitation were measured.The infrared absorption coefficients of OH- groups at 3μm according to the infrared transmission spectra were calcu-lated,and the constant KOH-Er,determined by the strength of interactions between Er3+ ions and OH- groups in the case of energy transfer was also calculated.The effect of hydroxyl content on mid-infrared emission properties of glass samples was discussed.The results show that the remnants OH- content of glass samples can be effectively reduced by the distillation processing.The 2.85μm mid-infrared fluorescence emission intensity and fluorescence lifetime of Er3+ ions are also enhanced.The calculated constant KOH-Er is about 1.08×10-16cm4/s.Because of the efficiency of energy transfer between Er3+ ions and OH- groups,the remnants of a small amount of OH- groups can still directly affect the intensity of 2.85μm fluorescence.