Dispersive Cylindrical Cloaks under Non-Monochromatic Illumination

TL;DR

This paper investigates how dispersive cylindrical cloaks respond to non-monochromatic waves, revealing effects like bandwidth limitations, frequency shifts, and delays crucial for designing metamaterial cloaking devices.

Contribution

It provides a numerical and analytical study of dispersive effects in cylindrical cloaks under broadband illumination, highlighting key performance factors.

Findings

Narrowband behavior dominates dispersive effects

Frequency shifts cause spatial and temporal disturbances

Losses reduce cloaking effectiveness

Abstract

Transformation-based cylindrical cloaks and concentrators are illuminated with non-monochromatic waves and unusual effects are observed with interesting potential applications. The transient responses of the devices are studied numerically with the Finite-Difference Time-Domain method and the results are verified with analytical formulas. We compute the effective bandwidth of several cloaking schemes as well as the effect of losses on the performance of the structures. We also find that narrowband behavior, frequency shift effects, time delays and spatial disturbances of the incoming waves are dominant due to the inherently dispersive nature of the devices. These effects are important and should be taken into account when designing metamaterial-based devices.