Impact of Merocyanine Dye Concentration in Ultrathin Polymer Films on Nonlinear Optical Response Due to the Aggregation Effect

Abstract

Nonlinear optical properties of thin films of the organic merocyanine dye derived from the class of malonodinitrile dyes, as well as its solid guest-host systems based on polymethyl methacrylate are studied. The optical absorption spectra of films with different dye concentrations and of the dye solutions in non-polar solvents are measured. The scattering indicatrices of films are presented. The films demonstrated the efficient photoinduced variation of the refractive index under the pulsed and continuous wave laser excitations. A nonlinear optical response of films under the picosecond range pulsed laser excitation points to the aggregation effects at the 10-wt.% dye concentration and higher.