Chemical Additive Cascading System – A new Scheme for Enhancing Optical Nonlinearity

Abstract

Nanophotonics is an emerging area where nanotechnology is used to change the physical and chemical properties of photonic materials or the effectiveness of photonic processes that have major applications in optical communication and computation. Though many photonic devices are developed using nonlinear optical materials, efforts are still going on to increase their efficiency toward 100% and other device characteristics toward their optimum level. In order to improve the efficiency of the third harmonic process further, we have a plan to use dye-sensitized metal nanoparticles doped in PMMA films. It is expected that the ability of nanotechnology in tailoring the physio-chemical properties of the materials will give rise to the optimum nonlinear devices to be used in nanophotonics. A considerable improvement in both nonlinear optical susceptibility and laser damage threshold is expected based on the results published in the case of dye-sensitized metal nanoparticle doped solar cells. Such a research may contribute to the efficient nanophotonic devices such as all optical switches, which are the basic building blocks of the final dream of realizing all optical computers. In this paper, a theoretical study is carried out on the effect of sensitization of some well-known nanocomposites TiO2/Au and ZnS/PVA by nonlinear DASPB dye-doped PMMA-MA polymer matrix in order to change the dielectric and nonlinear susceptibility. This is achieved by the systematic study of the size of nanoparticles used for the sensitization study, various donor-acceptor combinations, and concentration of dyes & nanoparticles in the sample films. The nonlinear absorption coefficient for each case and the theoretical optical limiting properties are expected to be modified based on cascaded nonlinear susceptibility for Type 1, Type 2, and Type 3 Z-scan configurations.

Keywords: Dye-sensitization, Nano-composites, Polymer films, Nonlinear absorption, Optical limiting.