Optical spectroscopy of Nd³⁺ in LiLuF₄ single crystals

Abstract

The polarized absorption spectra, polarized fluorescence spectra and fluorescence decay curve of Nd 3+ : LiLuF 4 crystals are measured at room temperature. The peak absorption cross-sections are 6.944×10 −20 cm 2 and 1.664 × 10 −20 cm 2 at around 795 nm with full-width at half-maximum of 3.4 nm and 3.2 nm for π-polarization and σ-polarization, respectively. Based on Judd–Ofelt theory, the spectral parameters of Nd 3+ in LiLuF 4 crystals are investigated. The emission probabilities, branching ratio and radiative lifetime for the transitions from 4 F 3/2 are calculated. The radiative lifetime, fluorescence lifetime and quantum efficiency are 536 µs, 489 µs and 91%, respectively. Its spectroscopic parameters are also compared with those of some other important Nd 3+ -doped laser crystals.