Second-harmonic generation and absorption studies of polymer–dye films oriented by corona-onset poling at elevated temperatures

Abstract

Second-harmonic generation and spectroscopic absorption measurements are used to study the nonlinear-optical thin-film properties of azo dye guest molecules oriented in a polymer host by corona-onset poling at elevated temperatures (COPET). Parallel-wire electrode and needle electrode configurations are studied. The orientational order of the nonlinear molecules, the internal electric field, and the stability of the second-harmonic properties are measured. The nonlinear properties stabilize after 10 days and remain relatively constant over a period of at least 8 months, and the films tolerate power densities of at least 60MW/cm2. Compared with other poling methods, COPET produces a more efficient long-range and long-term orientational order in the guest–host system studied, resulting in large, stable second-harmonic properties.