Temperature sensitivity boost

Appl. Phys. Lett. 108, 061902 (2016)

Optical temperature sensing based on making fluorescence intensity ratio measurements of two thermally linked transitions in rare-earth-doped materials is now a well-established concept. However, to date, the sensitivity of the approach has been a limitation. Researchers from Harbin Institute of Technology in China now report that the sensitivity of the approach can be dramatically improved by employing ferroelectric Pr³⁺-doped (K_0.5Na_0.5)NbO₃ (also known as KNN:Pr³⁺) as a sensing medium. The team achieve an ultrahigh sensitivity of 7,997/T², the highest value achieved so far and more than twice that of earlier work, by measuring the intensity ratio of the ¹D₂–³H₄ (603 nm) and ³P₀–³H₄ (489 nm) transitions under excitation with 325 nm ultraviolet light. Photoluminescence measurements made between 293 and 456 K confirm the validity of the approach.