ENHANCEMENT OF 2ND-HARMONIC POWER DUE TO SELF-CONSTRUCTION OF AN ANTI-GUIDE STRUCTURE IN A THIN-FILM WAVE-GUIDE OF A NONLINEAR-OPTICAL PHOTOCONDUCTING POLYMER

A theoretical analysis, to explain the increase of the Cerenkov-radiat ion-type second-harmonic power with time in a thin-film waveguide of a nonlinear-optical photoconducting polymer, is given. An anti-guide st ructure, which confines both a fundamental wave and its second-harmoni c wave, is gradually constructed by reorientation of the nonlinear-opt ical chromophores within the fundamental beam width in the thin-film p olymer. The space-charge field formed by the initially weak second-har monic wave itself causes the reorientation.