Optical spectroscopy of Pr3+ ion singly doped LiLuF4 single crystal by Bridgman method

Abstract

High quality LiLuF4 single crystals doped with various Pr3+ ions were synthesized by a vertical Bridgman method in completely sealed platinum crucibles. The excitation spectra spans from 420 nm to 500 nm. The prepared single crystals exhibit a blue band at 480 nm (3P0 → 3H4), a green band at 522 nm (3P1 → 3H5), and a red band at 605 nm (1D2 → 3H4) when excited at 446 nm; their corresponding average lifetimes are 38.5 µs, 37.3 µs, and 36.8 µs, respectively, which are much longer than those in oxide single crystals. The effects of excitation wavelength and doping concentration on emission intensities and chromaticity coordinates are investigated. The optimal Pr3+ concentration is confirmed to be 0.5%. The temperature dependent emission shows that the emission intensity constantly decreases with the increase of temperature from 298 K to 443 K due to the enhancement of non-radiative quenching at high temperature. The 3P0 → 3H4 transition is the most vulnerable to temperature, followed by the 3P1 → 3H5 transition and 1D2 → 3H4 transition.