Deposition of nanostructured methyl violet-10B films/FTO: Optical limiting and optical linearity/nonlinearity

Methyl violet-10B (MV-10B) nanostructured thin films are deposited onto highly cleaned conductive fluorine-doped SnO₂ substrates (FTO) using cost-effective spin coating method for the first time. The structure measurements including both X-ray diffraction and atomic force microscopy are used to describe the structure analysis and surface morphology of the studied films. Optical linearity and nonlinearity of MV-10B have been studied of different thicknesses. XRD of FTO is crystalline with different peaks and MV-10B thin film exhibit amorphous behavior. Indices of absorption, refractive, absorption coefficient and linear optical susceptibility are calculated and analyzed in details. Analysis of absorption coefficient gives the type of bandgap transition and two band gaps are established as follows: one at the higher energy which is related to FTO layer/glass and the other is laid at the lower energy which related to MV-10B and the film thickness is affected slightly. The parameter of nonlinear optical of these films such as nonlinear refractive index n⁽²⁾ and nonlinear optical susceptibility χ⁽³⁾ was calculated and analyzed. The studied nanostructure MV-10B thin films can be also in the optical limiting behavior of low/medium power of He–Ne/green lasers for controlling the laser beam power.