A significant enhancement of middle infrared fluorescence and upconversion of Er3+-doped transparent germanate glasses containing LaF3 nanocrystals

摘要： Er3+-doped oxyfluoride germanate glass containing LaF3 nanocrystals have been prepared via heat treatment from the precursor glass. Dynamic and static spectroscopic characteristics of IR, MIR and upconversion fluorescence of Er3+ doped transparent oxyfluoride germanate glass ceramic were investigated. When heat treat temperature increased from 540 to 600 (cid:1), NIR and MIR fluorescence intensity increase about 3 times, and companied with 2060 times 550 nm and 350 times 660 fluorescence enhancement. Increasing the heat treat time at 560 (cid:1) from 2 to 12 hours, the NIR and MIR fluorescence intensity increased about 2.5 and 1.8 times. It was due to the part of Er3+ ions were incorporated into LaF3 nanocrystals, resulting in the decrease of the multi-phonon relaxation of Er3+. According to the ratio between MIR fluorescence intensity of the heat treated glass sample to that of the untreated glass sample, the number of the Er3+ which was incorporated into the LaF3 nanocrystals can be quantificationally estimated. It was estimated to be 0.98% to 5.8% when the heat treat temperature increased from 540 to 600 (cid:1), and 1.21% to 1.63% with increasing heat treat time from 2 to 12 hours.