Photon cascade emission in Pr3+-doped fluorides

An overview about Pr3+-doped fluorides exhibiting photon cascade emission is given. The materials investigated, i.e. Pr3+-doped YF3, LuF3, PrF3, BaMgF4, LiCaAlF6, LiSrAlF6 and KMgF3, exhibit quantum cutting under vacuum ultraviolet (VUV) synchrotron excitation at wavelengths below 200 nm with a theoretical, internal quantum efficiency higher than one. This quantum efficiency was calculated with the Judd–Ofelt model, which allows the determination of the transition branching ratios. In the emission spectra bands due to the intraconfigurational 4f2→4f2 transitions originating from the 1S0 and 3P0 multiplets of the Pr3+-ion have been identified. In the excitation spectra in the ultraviolet/VUV spectral range, weak lines due to the 1S0 as well as broad bands due to the interconfigurational 4f2→4f5d transitions are observed.