Growth and fluorescence characteristics of Cr~(3+): YAG crystal fiber for temperature sensor from -10 ℃ to 500℃

摘要

The temperature-dependent characteristics of fluorescence of transient-metal doped and/or rare-earth-doped YAG has made these materials the focus of fluorescence thermometer. This article reports growth and fluorescence characteristics of Cr~(3+): YAG crystal fiber used for thermometer based on fluorescence decay time. Using a long pure YAG crystal fiber as the seed and a 0.1 at. % Cr_2O_3-doped Y_3Al_5O_(12) sintered powder rod as the source rod, a YAG fiber thermal probe with Cr~(3+)-ions doped end was grown by laser heated pedestal growth method. The crystal fiber shows good optical properties and mechanical strength and offers advantages of compact construct, high performance and ability to withstand high temperature. The fluorescence decay characteristics of the crystal fiber, including the temperature dependence of both fluorescence decay time and intensity, were comprehensively investigated. The experimental results indicated the Cr~(3+):YAG crystal fiber showed a monotonic relationship between the fluorescence lifetime and temperature over a wide temperature range from cryogenic to high temperature( > 500℃). The liber was found to be an excellent candidate material to be used as a fiber thermometer based on fluorescence lifetime. This thermometer may be used as temperature monitor in microwave treatment and Medium Voltage substations.