Luminescence thermometry based on time gates: highly sensitive approach for real time sensing and imaging

TL;DR

This paper introduces a luminescence thermometry method based on time-gated intensity ratios, enabling real-time thermal imaging with higher sensitivity and adjustable performance for various applications.

Contribution

The authors propose a novel time-gated luminescence intensity ratio approach that surpasses traditional decay profile analysis, allowing real-time thermal imaging with enhanced sensitivity.

Findings

Achieved higher relative sensitivity SR=17.1% K-1 for Ba2LaNbO6:1%Mn4+

Enabled real-time thermal imaging, unlike decay profile methods

Optimized thermometric performance by selecting appropriate gate lengths

Abstract

Undoubtedly, one of the most significant advantages of luminescence thermometry is its ability to be used not only for spot temperature measurements but also for imaging temperature changes. Among the commonly proposed approaches, luminescence thermometry based on luminescence kinetics holds particular promise. However, most thermometric studies rely on the analysis of luminescence decay profiles, a method that significantly hinders, if not entirely precludes, real-time thermal imaging. In this paper, we propose an alternative approach based on the luminescence intensity ratio integrated over two temporal gates. Tests conducted on two representative phosphors, Ba2LaNbO6:1%Mn4+ and Ca2LaNbO6:1%Mn4+, demonstrate that the proposed method not only enables thermal imaging but also achieves substantially higher relative sensitivity, reaching SR=17.1 % K-1 for Ba2LaNbO6:1%Mn4+ and SR=9.4 % K-1 for Ca2LaNbO6:1%Mn4+, compared to the conventional lifetime-based approach (SR=4.2 % K-1 for Ba2LaNbO6:1%Mn4+ and SR=1.2 % K-1 for Ca2LaNbO6:1%Mn4+). Furthermore, careful selection of gate lengths allows optimization of the thermometric performance of the proposed luminescent thermometers. This approach enables expansion of the thermal operating range at the cost of relative sensitivity, providing versatility to adapt the thermometer for specific applications.