Plasma electromagnetics: from optical computing to the study of topological interface states

The propagation of electromagnetic waves through uniform, non-magnetized, and even magnetized plasmas has been studied for more than a half-century. However, less is understood of how electromagnetic waves propagate through structured plasmas, i.e., plasmas that are non-uniform on scales of order the electromagnetic wavelength, or systems consisting of a collection of discrete plasma elements. In some communities, these spatially varying media fall under the category of metamaterials and photonic crystals. However, unlike traditional photonic crystals constructed from dielectric elements, plasma elements are dispersive, and conducting, supporting plasmonic responses that lead to unexpected transmission. Magnetized plasmas and plasma metamaterials are particularly interesting as they have recently identified topological features that facilitate the identification of interfacial states, which can support non-reciprocal (unidirectional) wave propagation. Finally, transient plasmas (uniform or not, magnetized or not) are also interesting in that they support the opportunity for tunable frequency conversion and power amplification. This presentation will describe our research exploring several of these phenomenon as they may pertain to applications such as cloaking, optical computing, and the development of non-reciprocal devices.