Optical temperature sensing in Tm3+/Yb3+-doped GeO2–PbO–PbF2 glass ceramics based on ratiometric and spectral line position approaches

Abstract

Development of new contactless thermometers with improved characteristics is highly demanded for science and technology. In this work, we present upconverting Tm3+/Yb3+-doped GeO2–PbO–PbF2 glass ceramics as optical temperature sensor. Upon 973 nm laser excitation, sample generates intense emission bands from blue to NIR regions due to ladder-like energy levels of Tm3+ ion. A ratiometric technique involving the Tm3+ thermally and non-thermally coupled levels (1G4(a), 1G4(b), 3F2,3, 3H4) and spectral line position of 3H4–3H6 transition was used to provide thermal sensing in the 300–466 K temperature range. The performance of suggested sensing parameters was compared and discussed in terms of relative thermal sensitivity. The maximal thermal resolution, which can be achieved using Tm3+/Yb3+-doped GeO2–PbO–PbF2 thermometers, is better than 1 K at both 303 and 465 K. The obtained results show the potential use of GeO2–PbO–PbF2: Tm3+,Yb3+ phosphor for optical sub-degree temperature sensing.