Energy transfer in LaF3: R3+, Pr3+ (where R = Nd, Dy)

Abstract
Fluorescence is observed for 1D2 levels of Pr3+ on exciting the higher lying level 3P0 in doubly doped systems LaF3: R3+, Pr3+ (R = Nd or Dy) but not in LaF3:Pr3+. From the recorded excitation spectra, and the measured decay times, it has been found that the drain mechanism of population to 1D2 levels is caused in doubly doped systems by ion‐pair relaxation between Pr3+ (3P01D2) and Nd3+ (ZX) or Dy3+ (ZY) ions.