Nonlinear transmission matrices of random optical media

TL;DR

This paper reports the direct measurement of the nonlinear transmission matrix in complex scattering media, demonstrating controllable and reversible nonlinear effects that could enable advanced optical applications.

Contribution

It introduces a method to measure the nonlinear transmission matrix of complex materials, specifically using silica aerogel with strong optothermal nonlinearity, revealing controllable dephasing effects.

Findings

Nonlinear transmission matrix can be directly measured in complex media.

Dephasing effects due to nonlinearity are controllable and reversible.

Potential for applications leveraging the nonlinear response of random media.

Abstract

Random media with tailored optical properties are attracting burgeoning interest for applications in imaging, biophysics, energy, nanomedicine, spectroscopy, cryptography and telecommunications. A key paradigm for devices based on this class of materials is the transmission matrix, the tensorial link between the input and the output signals, that describes in full their optical behavior. The transmission matrix has specific statistical properties, as the existence of lossless channels, that can be used to transmit information, and are determined by the disorder distribution. In nonlinear materials, these channels may be modulated and the transmission matrix tuned accordingly. Here we report the direct measurement of the nonlinear transmission matrix of complex materials, exploiting the strong optothermal nonlinearity of scattering Silica Aerogel (SA). We show that the dephasing effects due to nonlinearity are both controllable and reversible, opening the road to applications based on the nonlinear response of random media.