Updated Sellmeier Equations For Beta-Bab2o4

We present updated Sellmeier equations for beta-BaB2O4 based on measurements of the phase-matching angles for second-harmonic (SHG) and sum-frequency generation (SFG) of a Nd:YAG laser-pumped 90 degrees phase-matched RbTiOAsO4 optical parametric oscillator (OPO) and a Nd:YAG laser in the 0.6407 - 3.1392 mu m range. The phase-matching angles predicted by this index formula agree well with the recently published data points of SFG between a Ti:Al2O3 laser and a Nd:YAG laser-pumped KTiOAsO4 OPO in the 0.40 - 5.3 mu m range [G. Tamosauskas et al., Opt. Mater. Express 8, 1410 (2018)] as well as those for SFG below 0.2048 mu m thus far reported in the literature.