Resonant Spin Hall Effect of Light in Random Photonic Arrays

TL;DR

This paper demonstrates that disordered photonic arrays with Mie resonances can exhibit a giant and observable spin Hall effect of light at small scales, especially near resonances, and introduces a method to observe a time-dependent SHE.

Contribution

It reveals that Mie resonances enable a large, observable SHE in disordered media at small scales and proposes a new measurement approach for time-dependent SHE.

Findings

Giant SHE observed near Mie resonances in disordered arrays.

SHE can be detected at scales smaller than the mean free path.

Time-dependent SHE achievable through cooperative emission after abrupt extinction.

Abstract

It has been recently shown that the coherent component of light propagating in transversally disordered media, the so-called coherent mode, exhibits an optical spin Hall effect (SHE). In non-resonant materials, however, this phenomenon shows up at a spatial scale much larger than the mean free path, making its observation challenging due to the exponential attenuation of the coherent mode. Here, we show that in disordered photonic arrays exhibiting Mie resonances, the SHE on the contrary appears at a scale smaller than the mean free path if one operates in the close vicinity of the lowest transverse-magnetic resonance of the array. In combination with a weak measurement, this gives rise to a giant SHE that should be observable in optically-thin media. Furthermore, we show that by additionally exploiting the cooperative emission of a flash of light following the abrupt extinction of the incoming beam, one can achieve a time-dependent SHE, observable at large optical thickness as well.