Research Projects

Research is focused on modulating electromagnetic energy at sub-diffraction limit length scales, allowing for confinement, amplification, and switching of light in material platforms. This area has applications in on-chip optical communication, ultra-thin absorbers and emitters, quantum communication, and information processing. The weak nature of light-matter interactions, exemplified by the small value of the fine structure constant, poses the biggest hurdle. Consequently, research is focused on developing techniques and platforms to realize controllable strong interaction regimes, such as optical cavities and photonic resonators. Epsilon near zero (ENZ) systems, characterized by an ENZ wavelength (L_ENZ), have been realized in various meta-materials, but homogeneous ENZ materials like transparent conducting oxides and conducting polymers have a unique advantage. Their Drude-like dielectric constant enables ready tunability of L_ENZ via control of their free carrier density. The study explores applications of dynamic tuning of L_ENZ by carrier depletion/accumulation via electrical gating for switching waveguide modes in ENZ systems and to tailor emission from emitters embedded in ENZ material. Stabilization of the interaction via nonradiating modes is pertinent to understanding photonic quasiparticles like plasmon-polaritons that lead to extreme field confinement. Multilayer ENZ thinfilms with different L_ENZ can be used to tune and expand the ENZ spectral regime and create spectrally selective reflectors with step-function like reflectivity on both opaque and transparent substrates.