Temporal Brewster angle

TL;DR

This paper introduces the concept of a temporal Brewster angle using time-modulated metamaterials, enabling control over electromagnetic wave transmission and reflection in real time.

Contribution

It proposes the first theoretical and numerical analysis of a temporal Brewster angle, extending wave control concepts into the time domain with a novel metamaterial approach.

Findings

Analytical expression for the temporal Brewster angle derived.

Numerical simulations confirm the elimination of backward waves at this angle.

Potential for real-time electromagnetic wave control using temporal metamaterials.

Abstract

Controlling amplitude, phase and polarization of electromagnetic waves is key for a full manipulation of wave-matter interactions. The Brewster angle is one of the important features in this context. Here, we exploit metamaterial concepts with a time-modulated permittivity to propose the temporal equivalent of the spatial Brewster angle, a concept we call temporal Brewster angle. We consider temporal boundaries (as the temporal equivalent of the spatial boundaries between two media) by rapidly changing the permittivity of the medium, where a wave travels, from isotropic to an anisotropic permittivity tensor. It is theoretically shown that when the incidence angle coincides with that of the temporal Brewster angle a forward (temporal transmission) wave is produced while the backward (temporal reflection) is eliminated. We provide a closed-form analytical expression of the temporal Brewster angle and demonstrate its performance both theoretically and numerically. Our findings may provide a fresh view on how to control electromagnetic wave propagation and wave-matter interactions in real time using temporal metamaterials.