Cornell researchers are proposing a new way to modulate both the absorptive and the refractive qualities of metamaterials in real time, and their findings open intriguing new opportunities to control, in time and space, the propagation and scattering of waves for applications in various areas of wave physics and engineering.
The research published in the journal Optica, "Spectral causality and the scattering of waves," is authored by doctoral students Zeki Hayran and Aobo Chen, M.S. '19, along with their adviser, Francesco Monticone, assistant professor in the School of Electrical and Computer Engineering in the College of Engineering.
The theoretical work aims to expand the capabilities of metamaterials to absorb or refract electromagnetic waves. Previous research was limited to modifying either absorption or refraction, but the Monticone Research Group has now shown that if both qualities are modulated in real time, the effectiveness of the metamaterial can be greatly increased.
These temporally modulated metamaterials, sometimes referred to as "chrono-metamaterials" may open unexplored opportunities and enable technological advances in electromagnetics and photonics.
"What we demonstrate," Monticone said, "is that if you modulate both properties in time, you manage to absorb electromagnetic waves much more efficiently than in a static structure, or in a structure in which you modulate either one of these two degrees of freedom individually. We combined these two aspects together to create a much more effective system."
The findings may lead to the development of new metamaterials with wave absorption and scattering properties that far outperform what is currently available. For example, a broadband absorber has to be thicker than a certain value to be effective, but the material thickness will limit the applications of the design.
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