DIRECT EVIDENCE OF THE FAILURE OF ELECTRIC-DIPOLE APPROXIMATION IN SECOND-HARMONIC GENERATION FROM A CHIRAL POLYMER FILM

摘要

Second-harmonic generation from Langmuir-Blodgett films of a polythiophene is strongly influenced by the chirality of the polymer. The polarization dependence of the process cannot be explained in the electric-dipole approximation. Evidence of contributions beyond electric dipoles is obtained directly from individual second-harmonic signals. (C) 1997 American Institute of Physics. [References: 16]