Second-harmonic generation in mixed hemicyanine: fatty-acid Langmuir–Blodgett monolayers

Abstract

The second-order nonlinear optical properties of a hemicyanine-dye-containing monolayer are measured by using second-harmonic generation. An unexpected large enhancement of the second-harmonic signal from the dye is observed on dilution by optically passive fatty acid, with the maximum enhancement occurring at around 50% dilution. Possible mechanisms are discussed.