Abstract

It has been well recognized that introducing corrugative configuration into nonlinear optical (NLO) susceptibility χ⁽²⁾ results in an extreme enhancement of SHG power with quasi-phase-matching (QPM) scheme. The authors et al have also demonstrated significant SHG enhancement with the NLO corrugation even in the Cerenkov-radiative schemes¹-³. In these recent works the NLO corrugations have been electrically introduced with either contact-electrode or corona discharges. However, organic polymers have, in general, tendency to change their optical properties, i.e. refractive index and NLO susceptibility, with ultra-violet (UV) sbsorption. Fortunately, it has been found from spectroscopy that vinylidene cyanide/vinyl acetate (VDCN/VAc) copolymer has a strong absorption band around 200 nm wavelength. In addition, it has also been preliminarily expected that the UV irradiation tends to reduce or dissipate its NLO susceptibility and the refractive index due to dissociation of the side chain in VDCN/VAc co-polymer. In the present paper we shall thus attempt to enhance the Cerenkovian SHG power with a periodic or chirped NLO χ⁽²⁾ corrugation by irradiating ArF 193 nm laser source, together with discussion of the optimum UV irradiation.

© 1995 Optical Society of America