Abstract

Strong correlation between π-electrons in effectively reduced spatial dimensions^[1] is a guiding concept in designing organic materials possessing large nonlinear optical responses. Microscopic descriptions of second β_ijk(-ω₃;ω₁,ω₂) and third γ_ijkl(-ω₄;ω₁,ω_2,ω₃) order π-electron virtual excitation processes are required in order to understand at a fundamental level the physical properties and behavior of β_ijk and γ_ijkl and to provide guidelines for molecular designs of new material structures. The purpose of this paper is to report recent developments concerning the origin and mechanisms for γ_ijkl of quasi-1D conjugated structures and recent observations of optical bistability in quasi-2D structures.

© 1988 Optical Society of America