II.A.2.d.4.4 Terahertz Metasurfaces for Wavefront Control and Waveform Synthesis
Abstract
Major Goals: The major goal of this project is to explore the use of switchable metasurfaces for controlling terahertz waves. The project is specifically focused on a slab waveguide geometry, in which the metasurface serves as one of the waveguide boundaries. By varying the DC voltage applied to a patch of the metasurface, we can controllably vary the surface impedance of that patch, and thereby control the waveguide parameters. This should provide a facile method for both amplitude and (especially interesting) phase control of the propagating guided wave. The first goal, which has occupied much of our first year of research, has been to characterize the correlation between the voltage applied to the metasurface and the corresponding change in the surface impedance. We have adopted a two-pronged approach, in which we both compute and measure these changes. The measurements involve terahertz ellipsometry, and the calculations involve a combination of analytical and numerical methods. Once these results are complete and correlated, they will point the way towards subsequent measurements of voltage-controlled propagation effects in the slab waveguide geometry. We hope to demonstrate both frequency- dependent surface radiation (using a geometry in which the surface impedance is modulated along the propagation axis) and frequency-dependent beam steering (using a geometry in which the surface impedance is modulated along an axis perpendicular to the propagation axis). These two configurations will provide new capabilities for the manipulation of the spectral content of a terahertz wave, and for beam steering and wave front control. Both of these capabilities are crucial for the development of future terahertz systems, especially for wireless networking.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 04, 2018
- Source ID
- W911NF1510513
Entities
People
- Daniel Mittleman
Organizations
- Army Contracting Command
- Brown University
- United States Army