Infrared Detection and Waveguiding Using Metasurfaces
Abstract
The goal of this work is to be able to detect thermal radiation in the long-wave
and mid-infrared spectrum to a reasonable efficiency. In order to aid this effort,
antenna arrays with large collection apertures are coupled with infrared bolometers.
This dissertation shows the performance of a series-fed patch type of leaky-wave
antenna array coupled to a Nickel bolometer in terms of the angular-frequency
scanning abilities of the antenna. The antenna is then made out of electrooptic
Graphene in order to be able to dynamically tune the radiation properties of the
antenna. A two-dimensional leaky-wave antenna array made from Gold is shown to
be able to cover a conical swath of 360degrees in azimuth (ϕ) and 64degrees in
elevation (θ).
Improving the efficiency of the antenna requires designing the antenna out of a
low-loss material. To this effect, hybrid waveguides using phonon polaritons are then
explored. The hybrid waveguide performances are benchmarked using the
propagation length and field-confinement area (modal area) of the guided wave as
figures of merit. A hybrid waveguide is designed using Silicon Carbide and
hexagonal Boron Nitride. In the latter case, the unique hyperbolic properties that result in unique hybrid-waveguide modes based on volumetric hyperbolic phonons
are explored. Finally, a hybrid slot waveguide is designed using h-BN’s hyperbolic
surface phonon polaritons and is shown to have more modal confinement and longer
propagation length (lower loss) than the volumetric hyperbolic phonons. This novel
hyperbolic hybrid slot waveguide is then coupled into an antenna in order to radiate.