Investigation of temperature dependent tunable Goos—Hanchen shift at the interface of dielectric—nanocomposites containing non- spherical nanoparticles

Abstract

We develop a theoretical modeling of the temperature-dependent Goos-Hanchen (GH) shift of the reflected waves from the nanocomposites made of spheroidal metal nanoparticles in a dielectric host. The temperature impact on GH shift is explained by the temperature-dependence permittivity of metal nanoparticles with varying volume fraction in the visible and UV wavelength ranges from 250–400 nm for temperatures up to 1200 K. Simulation analysis is performed for both aligned metallic nanoparticles at room temperature and randomly oriented metallic nanoparticles at high temperatures. The effective permittivity of a composite (ϵeff) is calculated using the effective medium approximation theory and the stationary phase method is adopted to study the GH shifts. The impact of the change in the shape of the nanoparticles is simulated by the depolarization factor. Simulation results show that GH shift at elevated temperatures in pseudo-Brewster angle is more negative than the GH shift at room temperature for nanocomposites of small volume fraction with dielectric behavior and we find that the pseudo-Brewster angle is sensitive to the variation of temperature. Using Bruggman theory for numerical results, we show that varying the shape of spheroidal nanoparticles in dielectric nanocomposites leads to significant change in the value of GH shifts for some depolarization factors. Also based on the results, it is possible to obtain a transition from negative to positive GH shift just by adjusting the incident angle in a given depolarization factor. Moreover, the reversal GH shift may occur by adjusting the depolarization factor for a given wavelength, incident angle and volume fraction