Perfect Transmission through Disordered Media

TL;DR

This paper introduces complex-valued disordered permittivity profiles that are one-way reflectionless and perfectly transmitting for all angles, challenging the typical exponential decay of wave transmission in disordered media.

Contribution

It demonstrates the existence of complex-valued disordered media that are perfectly transmitting and reflectionless for all angles, unlike traditional real-valued profiles.

Findings

Complex-valued profiles are one-way reflectionless at all angles.

Real-valued profiles are reflectionless only at specific angles.

Transmission coefficient remains unity despite disorder.

Abstract

The transmission of a wave through a randomly chosen `pile of plates' typically decreases exponentially with the number of plates, a phenomenon closely related to Anderson localisation. In apparent contradiction we construct disordered planar permittivity profiles which are complex-valued (i.e. have reactive and dissipative properties) that appear to vary randomly with position, yet are one-way reflectionless for all angles of incidence and exhibit a transmission coefficient of unity. We contrast these complex-valued 'random' planar permittivity profiles with a family of real-valued, two-way reflectionless and perfectly transmitting disordered permittivity profiles that function only for a single angle of incidence and frequency.