Optical Temperature Sensors Based on Down-Conversion Nd3+,Yb3+:LiYF4 Microparticles

Nd3+ (0.3 mol.%), Yb3+ (0, 1, 2, 3 and 5 mol.%): LiYF4 phosphors were grown by the Bridgman–Stockbarger technique. The luminescence intensity ratio (LIR) of (4F3/2–4I9/2, ~866 nm) emission (2F5/2–2F7/2, ~980 was taken as a parameter. energy exchange between 4F3/2 (Nd3+) 2F5/2 (Yb3+) occurs via phonons, which elucidates LIR temperature dependence. influence cross-relaxation process on sensitivity estimated negligible. function depends concentration at fixed 0.3 mol.% Nd3+. maximum Sa Sr value reached for (0.3%), (1.0%): (Sa = 0.007 K−1 320 K) (5.0%): (Sr 1.03%*K−1 260 K), respectively.