Fluorescent contactless method for temperature determination of YAl₃(BO₃)₄ crystals doped with Yb³⁺ ions

Here we present an experimental implementation of the fluorescence concatless method for the temperature determination of YAl3(BO3)(4) crystals doped with Yb3+ ions. We have investigated the anti-Stokes fluorescence spectra of the crystal in the 900-1020 nm spectral range. The spectra have been measured while heating the crystal in the temperature range from 290 to 573 K. The increase of crystal temperature results in an enhancement of the relative fluorescence intensity in the short-wavelength region. The linear dependencies obtained can be used as a calibration function for contactless temperature measurements of YAl3(BO3)(4) laser crystals doped with Yb3+ ions.