Control of Glass–Metal Composite Optical Nonlinearity via Nanostructuring

We perform theoretical study of the nonlinear transmission and nonlinear diffraction in nanogratings etched at the surface of copper- and silver-based glass–metal composites. By assuming low metal concentration in the glass matrix, we employ Maxwell Garnett approach to obtain refractive index and absorption coefficient, while the optical nonlinearity of the composite is described using anharmonic oscillator model. We demonstrate that both nonlinear refraction and nonlinear absorption contribute to the light-induced transmittance of the nanostructured slab of the copper-based composite. In particular, in contrast to the silver-based composite, the nonlinear refraction modifies considerably the wavelength dependence of the light-induced transmission change in the copper copper-based composite.