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

Waveguides are formed in beta metaborate (beta-BBO) single crystals by Heion implantation. Both Y-cut and Z-cut samples are used. Refractive index p rofiles n(o) and n(e) are reconstructed from the effective indices measured by dark-line mode spectroscopy and by using an 1UIKB method. The profiles show a step-like guiding region. Optical barriers with depth to Delta n(e) = 0.04 and Delta n(o) = 0.1 for Y-cut and Delta n(e) = 0.08 and Delta n(o) = 0.05 for Z-cut sample are, respectively, obtained. The index changes obse rved in the electronic interaction region are small, 0.3 x 10(-2) for n(o) in both crystal cuts and -0.1 x 10(-2) and -0.8 x 10(-2) for n(e) in Y-cut and Z-cut, respectively. This is to our knowledge the first report on optic al waveguide characterization in this important non-linear material. (C) 20 00 Elsevier Science B.V. All rights reserved.