Abstract

Recently organic nonlinear optical (NLO) materials have been extensively investigated because of their large second-order nonlinear optical coefficients and ultra fast response in the field of optoelectronics[1]. In order to obtain a highly efficient second harmonic generation (SHG), the materials match the phase velocity over the long propagation distance for light at fundamental and harmonic waves. To realize phase-matching, a general technique is using natural birefringence in certain anisotropic crystal to compensate the refractive index dispersions between the fundamental and second harmonic wavelength and fulfill nω = n2ω. The advantages of birefringence phase-matching is that one can satisfy this condition relatively easy by rotating the crystal. Recently the bulk-type phase-matched SHG was observed for the first time from poled polymers with large positive birefringence[2]. The conversion efficiency of this SHG device is not enough because of small nonlinear optical coefficients. Large off-diagonal tensor components are required to improve the conversion efficiency of bulk type SHG devices. However the molecular design concept and their assembly to optimize off- diagonal tensor component are not clear. In this presentation, the effects of drawing on second order nonlinear optical coefficients of poled polymers will be discussed using A type main chain polymers and a side chain polymer.

© 1995 Optical Society of America