Porous and phase change nanomaterials for photonic applications

Abstract

The field of nanophotonics has emerged as a promising platform for applications ranging from communications and computing, to sensing, solar energy harvesting, biomedicine, and beyond. Advancing these technologies requires developing and implementing new material systems, designs, and fabrication strategies. This dissertation focuses on two classes of nanomaterials with attractive optical characteristics: (1) porous nanomaterials and (2) phase change nanomaterials. Direct imprinting of porous subtrates (DIPS) is first introduced and demonstrated for the low-cost fabrication of micro- and nano-structures in porous media, including plasmonic or diffraction based sensors and porous microparticles relevant to drug delivery and imaging. DIPS is further demonstrated for 3D surface patterning and morphological control over local material properties. Second, the phase change nanomaterial vanadium dioxide (VO2) is integrated with silicon photonic components and a new ultra-compact platform for constructing active optical devices is demonstrated. With the hybrid Si-VO2 platform, record values of optically induced phase modulation and absorption modulation are achieved. The slotted photonic crystal nanobeam is also introduced and a low-mode volume nanocavity is demonstrated as an ultra-compact device for enhancing light-matter interactions, thus promoting further improvements to device footprint, sensitivity, and efficiency.