Stimulated Brillouin scattering in metamaterials

TL;DR

This paper develops theoretical methods to calculate stimulated Brillouin scattering (SBS) properties in dielectric metamaterials, revealing how structural parameters influence SBS gain and linewidth, with potential for significant enhancement or suppression.

Contribution

It introduces a comprehensive framework for calculating SBS parameters in metamaterials, highlighting the roles of electrostriction and other factors in SBS gain modulation.

Findings

Demonstrates order of magnitude SBS gain enhancement.

Shows SBS gain can be perfectly suppressed.

Identifies parameters beyond electrostriction that influence SBS.

Abstract

We compute the SBS gain for a metamaterial comprising a cubic lattice of dielectric spheres suspended in a background dielectric material. Theoretical methods are presented to calculate the optical, acoustic, and opto-acoustic parameters that describe the SBS properties of the material at long wavelengths. Using the electromagnetic and strain energy densities we accurately characterise the optical and acoustic properties of the metamaterial. From a combination of energy density methods and perturbation theory, we recover the appropriate terms of the photoelastic tensor for the metamaterial. We demonstrate that electrostriction is not necessarily the dominant mechanism in the enhancement and suppression of the SBS gain coefficient in a metamaterial, and that other parameters, such as the Brillouin linewidth, can dominate instead. Examples are presented that exhibit an order of magnitude enhancement in the SBS gain as well as perfect suppression.