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

In this paper, the polarized absorption and fluorescence spectra of Nd3+ ion in the BaCaBO3F 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 x 10(-20) cm(2) and 15.21 x 10(-20) cm(2) at 1068 nm for pi- and sigma-polarization using the Fuchtbauer-Ladenburg (F-L) equation. The fluorescence lifetime of F-4(3/2) manifold is equal to 57.7 mu s, and the quantum efficiency is 26.8%, which is higher than those of most of other borates. The potential of Nd3+:8aCaBO(3)F as a new self-frequency doubling laser crystal has also been evaluated preliminarily. Appreciable self-absorption at the second-harmonic wavelength of Nd3+:BaCaBO3F crystal should be considered for further laser operations. (C) 2010 Elsevier B.V. All rights reserved.