Transverse Fresnel-Fizeau drag effects in strongly dispersive media

TL;DR

This paper explores enhanced transverse Fresnel-Fizeau drag effects in strongly dispersive media with slow group velocities, predicting novel upstream drag phenomena and complex light propagation behaviors.

Contribution

It introduces the prediction of significant upstream Fresnel-Fizeau drag and complex light path effects in strongly dispersive media, expanding understanding of slow-light phenomena.

Findings

Enhanced drag effects in EIT media with slow group velocities

Prediction of upstream drag for negative group velocities

Complex light paths due to higher order dispersion effects

Abstract

A light beam normally incident upon an uniformly moving dielectric medium is in general subject to bendings due to a transverse Fresnel-Fizeau light drag effect. In conventional dielectrics, the magnitude of this bending effect is very small and hard to detect. Yet, it can be dramatically enhanced in strongly dispersive media where slow group velocities in the m/s range have been recently observed taking advantage of the electromagnetically induced transparency (EIT) effect. In addition to the usual downstream drag that takes place for positive group velocities, we predict a significant anomalous upstream drag to occur for small and negative group velocities. Furthermore, for sufficiently fast speeds of the medium, higher order dispersion terms are found to play an important role and to be responsible for peculiar effects such as light propagation along curved paths and the restoration of the spatial coherence of an incident noisy beam. The physics underlying this new class of slow-light effects is thoroughly discussed.