Nanophotonics of low-dimensional semiconductor oxides in the infrared and terahertz regimes

Abstract

Nanostructured semiconductors represent one of the most relevant advances in Science with applications in several areas of the industry. However, employing them for the development of nanophotonic devices is still a challenge. In contrast, two-dimensional materials, such as graphene and others, have proved to be exceptional platforms for the confinement of light at the nanoscale. Through the coupling of light with fundamental resonances of matter, hybrid modes of light and polarization, called polaritons, can be confined beyond the diffraction limit. Recently, Semiconductor Oxides (SO) have presented themselves as alternative materials, demonstrating exotic polaritonic properties, such as anisotropic propagation in the plane, chemically tunable dispersion, and vibration activity in the mid-infrared (Mid-IR) to Terahertz (THz). Despite these advances, there is still a diversity of nanostructured SO that can be exploited. In this project, we will study the polaritonic properties of SO, such as h-MoO3, TeO2, and SnO2 designed and fabricated through electron beam lithography (e-beam) and plasma corrosion to operate as nanoresonators and waveguides. Numerical simulations will support the design of resonant nanostructures so that they can be fabricated in an optimized way. Through Scattering Near-Field Optical Microscopy (s-SNOM) and other experimental techniques, we will access the fundamental nano-optical properties of these materials. We emphasize that the results foreseen in this research can potentially serve as basis for the development of new nanophotonic devices in the Mid-IR to the THz ranges. (AU)