Spectral and optical nonlinear characteristics of methylene blue-titanate nanohybrid film

The method for preparing solid thin films with high-order nonlinear effects was explored, and the optical properties of the materials were investigated to obtain an ideal nonli-near optical device. The MB/HTO nanohybrid thin film was prepared by intercalating reaction between the dye and titanate nanosheets. The spectral characteristics of methylene blue dye before and after intercalating into layered titanate nanosheets and forming a nanohybrid thin film were investigated by measuring absorption and fluorescence spectra. It was found that the absorption peak of the film generated a more obvious blue shift than that of the solution, which indicated the formation of H-aggregates of the dye in the interlayer space of nanosheets. In addition, the nonlinear optical properties were studied using single beam Z-scan technique under irradiation of low power continuous wave (CW) produced by He-Ne laser with a wavelength of 632.8 nm. The sample exhibited a negative (self-defocusing) nonlinearity and large nonlinear refractive index with an order of 10-10 m2/W.