Microwave sink using plasma based localized surface plasmons

TL;DR

This paper demonstrates that sub-wavelength plasmas can act as passive microwave sinks by exciting localized surface plasmon resonances, enabling intense wave focusing beyond the diffraction limit for potential applications in imaging and communication.

Contribution

It introduces the concept of using plasma-based localized surface plasmons to achieve microwave wave focusing, extending plasmonic phenomena into the microwave regime.

Findings

Sub-wavelength plasmas support localized surface plasmon resonances.

Plasmas can function as passive microwave sinks.

Enhanced wave focusing beyond diffraction limit achieved.

Abstract

Overcoming the diffraction limit, meaning focusing waves on a sub-wavelength scale, has received considerable attention for applications involving light and acoustics. Indeed, the intense focusing achieved enhances the interactions between waves and matter, and the improved spatial resolution opens up possibilities in fields such as imaging, detection and communication. In optics, a passive sink may be obtained if the incident light couples to localized surface plasmon (LSP) resonances, resulting in Coherent Perfect Absorption condition. The presence of optical surface plasmons at metal interfaces is due to the angular frequency of metals, which lies in the optical regime due to their high density of free electrons. Plasmas, which consists of ionized gazes with a lower electron density, can support surface plasmons in the microwave regime. Hence, we demonstrate in this paper that sub-wavelength plasmas behave as a passive microwave sink by exciting LSP resonance inside the plasma.