Exploring the physical principles of electromagnetic energy harvesting in GHz and THz metamaterials.

Metamaterials, consisting of periodically arranged sub-wavelength structures, exhibit extraordinary electromagnetic (EM) properties that can be used for a wide range of applications such as subdiffraction imaging, EM induced transparency, and invisible cloaking. Recently, metamaterial absorbers get a lot of attention as ambient EM energy harvester to absorb, for example, unused energy from wireless hotspots, and convert it into electric currents as a source of cheap and renewable energy. Unfortunately, a major part of absorbed energies in metamaterials is dissipated via dielectric losses, limiting the applicability for energy harvesting. In addition, several fundamental questions dealing with the dynamics of the energy dissipation that may be essential to boost up the conversion efficiency, have not been addressed.

In this proposal, we will explore the fundamental physics of dissipation processes in metamaterial absorbers for harvesting GHz and THz EM radiation. We will 1) study the energy conversion process in GHz and THz metamaterials that are designed for high-efficient energy harvesting by simultaneously excitation of electric and magnetic resonances; 2) design and characterize metamaterials that show broadband perfect absorption behavior for simultaneous harvesting of multiple energy sources; and 3) identify the main dissipation processes following radiation absorption in THz metamaterials and quantify their corresponding time scales.