Ga_2O_3 microwires as wide dynamical range temperature sensors

Abstract

In this work, we present our recent results on the applicability of optical microcavities based on Cr doped Ga_2O_3 wires to operate as a nanothermometer in a wide temperature range (at least from 150 up to 550 K) and achieving a temperature precision of around 1 K. To this purpose, DBR (distributed Bragg reflectors) have been used to enhance the reflectivity at the lateral ends of the wires. The transduction mechanism encompasses both the luminescence features of the characteristic R-lines of Cr^(3+) ions in this host as well as the interferometric effects of the Fabry-Perot resonances within the cavity.