Nonlinear grating behavior of phthalocyanine Langmuir-Blodgett films

Optical second-harmonic generation was observed from nickel tetracumylphenoxy phthalocyanine films deposited on quartz by the Langmuir-Blodgett (L-B) technique. The L-B films consist of microcrystallites, i.e., phthalocyanine aggregates, which have a preferred in-plane orientation with respect to the deposition direction. The L-B films also display characteristics of a nonlinear grating with the same periodicity and groove depth over the entire surface. This is to our knowledge the first time that such nonlinear grating behavior has been observed from an organometallic multilayer film.