Twisted light by a Kerr-like TiO2 thin film with Au-Pt nanoparticles

Third-order nonlinear optical effects exhibited by Gold-Platinum nanoparticles in a Titanium Dioxide thin solid film were induced by a two-wave mixing configuration with digitally-modulated irradiance profiles. The nanomaterials were prepared by a sol-gel method, and a spinning coating technique was employed for the preparation of the samples in thin film form. We used a Nd:YAG laser system at 532 nm wavelength and 4 nanosecond for the exploration of the thirdorder optical nonlinearities. The characterization of the morphology and optical transmittance was carried out by transmission electronic microscopy and UV-vis spectroscopy studies; respectively. A round continuously variable nonlinear refractive index was proposed to generate twisted light by nanosecond pulses in the sample. The system was designed with a randomly distributed density of the nanoparticles. This technique can be considered an alternative for performing ultrafast all-optical instrumentation functions.