DIRECT EVIDENCE OF THE FAILURE OF ELECTRIC-DIPOLE APPROXIMATION IN 2ND-HARMONIC GENERATION FROM A CHIRAL POLYMER FILM

Second-harmonic generation from Langmuir-Blodgett films of a polythiop hene is strongly influenced by the chirality of the polymer. The polar ization dependence of the process cannot be explained in the electric- dipole approximation. Evidence of contributions beyond electric dipole s is obtained directly from individual second-harmonic signals. (C) 19 97 American Institute of Physics.