Optomechanics of random media

TL;DR

This paper explores how structural disorder in media can enhance optomechanical interactions, revealing that disorder can be harnessed to improve light-driven mechanical effects rather than hinder them.

Contribution

It demonstrates that disorder increases optomechanical forces and fluctuations, especially near the Anderson transition, challenging the assumption that scattering reduces optomechanical effects.

Findings

Disorder enhances optical forces at the Anderson transition.

Optomechanical fluctuations reach a maximum when Thouless conductivity is below unity.

Disorder can be exploited for designing advanced optomechanical devices.

Abstract

Using light to control the movement of nano-structured objects is a great challenge. This challenge involves fields like optical tweezing, Casimir forces, integrated optics, bio-physics, and many others. Photonic "robots" could have uncountable applications. However, if the complexity of light-activated devices increases, structural disorder unavoidably occurs and, correspondingly, light scattering, diffusion and localization. Are optically-driven mechanical forces affected by disorder-induced effects? A possible hypothesis is that light scattering reduces the optomechanical interaction. Conversely, we show that disorder is a mechanism that radically enhances the mechanical effect of light. We determine the link between optical pressure and the light diffusion coefficient, and unveil that when the Thouless conductivity becomes smaller than the unity, at the so-called Anderson transition, optical forces and their statistical fluctuations reach a maximum. Recent advances in photonics demonstrate the possibility of harnessing disorder for fundamental physics and applications. Designing randomness allows new materials with innovative optical properties. Here we show that disorder and related phenomena may be exploited for optomechanical devices.