Fiber-optic thermometer using Cr-doped YAlO3 sensor head

Abstract

Cr-doped ${\mathrm{YAlO}}_3$ phosphor crystals have been grown and characterized for applications in fiber-optic thermometers based on the temperature dependence of the photoluminescence (PL) lifetime. PL peaking at $\text{λ=735\hspace{0.17em}}\mathrm{nm}$ is observed from the crystals following an excitation by a light-emitting diode at $\text{λ=520\hspace{0.17em}}\mathrm{nm}.$ Long PL lifetime $\text{(τ=43.14\hspace{0.17em}}\mathrm{ms})$ is observed from Cr-doped ${\mathrm{YAlO}}_3$ at room temperature as compared with those of ruby $\text{(τ=4.2\hspace{0.17em}}\mathrm{ms})$ and spinel $\text{(τ=8.0\hspace{0.17em}}\mathrm{ms}\mathrm{).}$ The temperature coefficient (−0.075 ms/K) of Cr-doped ${\mathrm{YAlO}}_3$ is also larger than those of ruby (−0.010 ms/K) or spinel (−0.037 ms/K). ${\mathrm{YAlO}}_3$ is considered to be a sensitive sensor head material for fiber-optics thermometers.