Saturation effects in the upconversion efficiency of Er-doped fluorozirconate glasses

Abstract

A series of transparent erbium-doped fluorozirconate glasses has been investigated usingdifferential scanning calorimetry, optical absorption, and upconverted fluorescencespectroscopy. The upconverted fluorescence intensity versus excitation power dependenceshows that the ratio of the two-photon upconverted emission in the near infrared at 980 nmto the three-photon upconverted emissions in the visible at 530, 550, and 660 nm decreaseswith increasing excitation power. The integrated upconverted fluorescence intensity toexcitation power ratio shows ‘saturation’ with increasing excitation power, while the pointof saturation shifts to lower excitation power with increasing erbium concentration. Theexperimental lifetime of the upconverted fluorescence decreases with increasing erbiumconcentration.