Refined Sellmeier equations for BaGa4S7

This paper reports refined Sellmeier equations for the biaxial nonlinear crystal B a G a 4 S 7 that provide a good reproduction of the phase-matching angles for second-harmonic generation (SHG) and sum-frequency generation (SFG) of the mid-IR outputs of Nd:YAG and Ho:YLF laser-pumped optical parametric oscillators (OPOs) and a frequency-doubled C O 2 laser in the 0.7584–8.018 µm range. The theoretical results are found to agree with the recent experimental data for 1-µm-pumped optical parametric processes based on B a G a 4 S 7 beyond 8 µm.