Phase-matched second-harmonic generation from free-standing periodically stacked polymer films

Abstract

Visible green light has been observed by quasi-phase-matched second-harmonic generation from a periodic stack of free-standing poled polymer films, when pumped by a cw mode-locked near-infrared laser. The total thickness of the polymer film and phase-matching length was 300 μm with a conversion efficiency of 10−6–10−5 depending on absorption. A polymer thin film processing technique is described for this application that could make large area poled and stretched films with enhanced nonlinear optical susceptibilities.