Precise estimation of nonlinear-optical coefficients for anisotropic nonlinear films with C_∞V symmetry

Abstract

An extended theory of Maker fringes, applicable to extraordinary waves, is presented for the exact estimation of nonlinear-optical coefficients d31 and d33 of anisotropic films with C∞υ symmetry, such as poled and Langmuir-Blodgett films. Numerical data show that, while the value of d31 decreases with increasing anisotropy of the refractive index at the harmonic frequency, the value of d33 increases remarkably. Therefore, if anisotropy of a few percent is neglected, as in conventional estimations, the values of d31 and d33 are overestimated and underestimated, respectively, and large errors occur. Moreover, d33 strongly depends on the anisotropy at the fundamental frequency.