Electromagnetic Time Interfaces in Wire Media: Innovations for Subwavelength Imaging

TL;DR

This paper explores how temporal interfaces in wire media can transform subwavelength spectra into higher frequency plane waves, potentially enabling advanced subwavelength imaging techniques.

Contribution

It introduces a theoretical framework for temporal transitions in wire media, transforming subwavelength spectra into propagating plane waves at higher frequencies.

Findings

Transformation of subwavelength spectra into higher frequency plane waves

Different frequencies propagate in different directions after transition

Unique relation between wave amplitudes and initial spatial harmonics

Abstract

In this work, we theoretically study temporal interfaces between media with strong spatial dispersion and dielectrics. In particular, we consider a temporal discontinuity that transforms a wire medium sample, a metamaterial with resonant spatial dispersion, into a uniaxial dielectric. We show that this transition results in a transformation of the deeply subwavelength spatial spectrum of TEM waves propagating in the wire medium at a certain frequency into a spectrum of plane waves at new frequencies that are all higher than the initial one. The waves at different frequencies propagate in different directions. Their complex amplitudes and propagation directions are uniquely related to the amplitudes of the spatial harmonics of the fields which existed before the transition. We explain how to implement this transition. The revealed effect may result in a promising method of subwavelength imaging.