IMPROVEMENT OF THE CERENKOV RADIATIVE 2ND HARMONIC-GENERATION IN THE SLAB WAVE-GUIDE WITH A PERIODIC NONLINEAR OPTICAL SUSCEPTIBILITY

Introducing a periodically corrugated nonlinear optical (NLO) susceptibility chi(2) in the guiding layer of a three-layered slab waveguide, we propose a Cerenkov radiative second harmonic generation (SHG) with numerical calculations, and experimentally demonstrate it. With vinylidene cyanide/vinyl acetate copolymer film having a sinusoidal chi(2) corrugation of 60 mum period as a guiding layer, the Cerenkov scheme of SHG was enhanced over a wide film thickness range at 1. 06-mum fundamental wavelength, obtaining an enhancement factor of approximately 1. 5 in comparison with a uniform chi(2) scheme. Experimental dependences of the SHG power on both corrugation period and path length agree well with theoretical estimates, indicating usefulness of the modified Cerenkovian SHG with the corrugated chi(2).