We focus on two main areas in this study: firstly, we concentrate on computational nanophotonic methods, such as the Fourier-Modal Method (FMM) or Rigorous Coupled Wave Analysis (RCWA), which is the method of choice for investigating homogeneous amorphous thin films and periodic nanogratings. Homogeneous amorphous thin films provide a simple platform for studying nonlinear behavior related to structural and amorphous properties, while nanogratings introduce additional geometrical complexity, especially when filled with metal nanoparticles in a host material. The second, is applying effective medium theories such as Maxwell Garnett and Bruggeman to introduce metal nanoparticle distributions. In homogeneous amorphous thin films the distribution of gold and iridium nanoparticles strongly influences the effective nonlinear susceptibility of the materials, increasing it by an order of magnitude in the case of gold due to localized surface plasmonic resonance. The enhancement of nonlinear strength in amorphous composites with respect to the bulk material has an upper limit in metallic composites as dominating absorption effects take over at higher fill factors. Both saturated and induced absorption in the thin films of amorphous composites was observed depending on the selected frequency and relative position to the resonant frequency of electron excitation in metallic inclusions. We demonstrated the depths at which thin films are affected by nonlinear enhancement effects.
Navid Daryakar (Thu,) studied this question.