An approximate deconvolution method for the luminescence intensity ratio calculations from overlapping emissions

Abstract Two experimental practices in luminescence intensity ratio (LIR) thermometry based on the spectral deconvolution (SD) and separation at chosen wavelength (WS) were analyzed for the case when sharp emission is overlapping with a broad one, which is frequently the case for Cr3+ and Mn4+ in the intermediate or strong crystal fields. Their performances were compared showing that, depending on several parameters, separation at chosen wavelength method gives lower sensitivities than spectral deconvolution one. With requirement that the sharp emission quenches at high temperatures, which is also the case for the mentioned luminescent centers, an alternative method, named approximate deconvolution (AD) is proposed. The novel method retains the simplicity of the WS, while matching the sensitivities of the SD method. The detailed algorithm for the AD method is presented. Although the temperature resolution is not improved, the AD method allows fit to the Boltzmann equation and extraction of the physically relevant parameters. All three methods are compared using Cr3+ emission in LiAl5O8, MgAl2O4 and YAG showing that WS gives significantly lower sensitivities than SD and AD, while SD and AD are highly matching in performance.