Abstract

Polyacetylene is a long linear, chainlike material whose optical properties at visible wavelengths arise from the motion of the π-electrons along the bonds that connect the sites. The nonlinear optical properties of polyacetylene materialize from two anharmonic electronic interactions: (1) the π-electrons interact with the phonons and (2) they interact with each other through their Coulomb repulsion. The motion of the π-electrons driven by an optical field were described within a classical framework and the third-order optical susceptibility associated with phase conjugation was determined. The wavelength (λ) has dependence on the nonlinear optical susceptibility; two peaks coincide with a resonant response. A low frequency peak in the vicinity of 1.2 µm reflects a two-photon resonance process and arises from the Coulomb repulsion. A high frequency peak at 0.6 µm is the single photon resonance and arises from both the Coulomb repulsion and the electron phonon coupling.

© 1991 Optical Society of America