Experimental Realization of an Achromatic Magnetic Mirror based on Metamaterials

TL;DR

This paper reports the experimental creation of a broadband, low-loss, polarization- and angle-insensitive magnetic mirror using metamaterials, surpassing previous narrowband resonant designs and applicable across various spectral regions.

Contribution

The authors demonstrate a frequency-independent, non-resonant magnetic mirror with record performance at millimetre wavelengths, enabling broader applications in optics and electromagnetics.

Findings

Achieved 144% bandwidth with <1% losses

Device performance is angle- and polarization-independent

Operates effectively at millimetre wavelengths

Abstract

Our work relates to the use of metamaterials engineered to realize a meta-surface approaching the exotic properties of an ideal object not observed in nature, a "magnetic mirror". Previous realizations were based on resonant structures which implied narrow bandwidths and large losses. The working principle of our device is ideally frequency-independent, it does not involve resonances and it does not rely on a specific technology. The performance of our prototype, working at millimetre wavelengths, has never been achieved before and it is superior to any other device reported in the literature, both in the microwave and optical regions. The device inherently has large bandwidth (144%), low losses (<1 %) and is almost independent of incidence-angle and polarization-state and thus approaches the behaviour of an ideal magnetic mirror. Applications of magnetic mirrors range from low-profile antennas, absorbers to optoelectronic devices. Our device can be realised using different technologies to operate in other spectral regions.