Helium ion-implanted planar waveguide in Y-cut and Z-cut β-BBO (BaB2O4)

Abstract Waveguides are formed in beta metaborate (β-BBO) single crystals by He + ion implantation. Both Y -cut and Z -cut samples are used. Refractive index profiles n o and n e are reconstructed from the effective indices measured by dark-line mode spectroscopy and by using an i WKB method. The profiles show a step-like guiding region. Optical barriers with depth to Δ n e =0.04 and Δ n o =0.1 for Y -cut and Δ n e =0.08 and Δ n o =0.05 for Z -cut sample are, respectively, obtained. The index changes observed in the electronic interaction region are small, 0.3 × 10 −2 for n o in both crystal cuts and −0.1 × 10 −2 and −0.8 × 10 −2 for n e in Y -cut and Z -cut, respectively. This is to our knowledge the first report on optical waveguide characterization in this important non-linear material.