Near-zero-index nanophotonic technologies

ongoing

Near-zero-index (NZI) media is a family of photonic nanostructures (continuous media and/or metamaterials) characterized by a near-zero refractive index. As the refractive index approaches zero, spatial and temporal variations of the electromagnetic field decouple, giving rise of a regime of qualitatively different light-matter interactions. Therefore, NZI nanostructures exhibit a unique optical response, where a concept as basic as the geometry plays an essentially different role. Examples of the exotic wave phenomena include transmission through deformed waveguides, cavities whose resonant frequency does not depend on the geometry of their external boundary, nonradiating modes in three-dimensional open cavities, violation of effective medium theories, anomalous dispersion, nonperturbative nonlinear optics, to name a few. These unconventional effects have a high potential for technological innovation. However, the crucial challenge of transforming these basic phenomena into practical devices has not yet been addressed. In NZINATECH, we will address this challenge pushing forward the basic theoretical research on NZI media to the stage of NZI nanophotonic technologies. To this end, we have outlined an ambitious research plan that includes the experimental demonstration of NZI devices in different material platforms, including polar dielectrics, doped semiconductors and silicon photonics. This multidisciplinary research plan will combine the fields of NZI media, metamaterials, quantum optics, electron-beam spectroscopy, thermal emission and silicon photonics. Our results will also open new areas of research for NZI media, including nontrivial interactions of NZI optical modes with free-electrons and small quantum systems. Finally, by examining fundamental questions in limiting cases (i.e., extreme constitutive parameters) we will provide a better understanding of the quantum theory of light-matter interactions.