Polarized spectroscopic properties of a potential self-frequency doubling crystal, Nd3+:BaCaBO3F

Abstract In this paper, the polarized absorption and fluorescence spectra of Nd 3+ ion in the BaCaBO 3 F non-linear optical crystal have been investigated at room temperature. The Judd–Ofelt theory, extended to anisotropic system, has been applied to calculate the phenomenological intensity parameters, spontaneous transition probabilities, branching ratios and radiative lifetimes. The maximum emission cross-sections have been calculated to be 7.22 × 10 −20 cm 2 and 15.21 × 10 −20 cm 2 at 1068 nm for π - and σ -polarization using the Fuchtbauer–Ladenburg (F–L) equation. The fluorescence lifetime of 4 F 3/2 manifold is equal to 57.7 μs, and the quantum efficiency is 26.8%, which is higher than those of most of other borates. The potential of Nd 3+ :BaCaBO 3 F as a new self-frequency doubling laser crystal has also been evaluated preliminarily. Appreciable self-absorption at the second-harmonic wavelength of Nd 3+ :BaCaBO 3 F crystal should be considered for further laser operations.