Nonlinear, passive and active inclusions to tailor the wave interaction in metamaterials and metasurfaces
MetadataShow full item record
Metamaterials have experienced a rapid growth of interest over the past few years and new capabilities are being explored to broaden the range of their unique electromagnetic properties for functional devices, including tunable, switchable, and nonlinear properties. In the future, there is the prospect of opening even more exciting applications with metamaterials, not yet imagined and thought not to be possible with currently available techniques. In my dissertation, I discuss several solutions for passive and active metamaterials and metasurfaces, with a particular focus on their potential applications, enabling a new class of metamaterials in the spectral range from radio frequencies (RF) and microwaves, terahertz (THz) to visible light. First, I demonstrate that by loading plasmonic nanoantennas with nonlinear nanoparticles, the nonlinear optical processes, such as multiple wave mixing, high harmonic generation, phase conjugation and optical bistability may be realized at the nanoscale, thanks to the strongly enhanced optical near fields accompanied with the plasmonic resonance. I present here the design, practical realization, and homogenization theory of nonlinear optical metamaterials and metasurfaces formed by optical nanoantenna arrays loaded with nonlinearities. As an extreme case of light manipulation at the "atomic" scale, I also study the collective oscillation of massless Dirac fermions inside grapheme monolayers, in which surface plasmon polaritons are controlled by electrostatic gating. I present how a graphene monolayer may serve as a building block and design paradigm for adaptable, switchable and frequency-configurable THz metamaterials and nanodevices, realizing various functionalities for cloaking, sensing, absorbing, switching, modulating, phasing, filtering, impedance transformation, photomixing and frequency synthesis in the THz spectrum. Last I present various metamaterial designs applied to invisibility cloaks based on the scattering cancellation mechanism enabled by plasmonic materials and passive/active metamaterials and metasurfaces. This cloaking technology may be used for camouflaging, enhancing the sensitivity and signal-to-noise ratio in RF wireless communication and sensor networks. In addition, electrically-small antennas based on the phase compensation effect offered by metamaterials with low or negative material properties are presented, with tailorable modal frequencies, bandwidth, and radiation properties.