NanoPlasmonics, Microphotonics & Imaging

Optical antennas are widely used in surface-enhanced Ramon spectroscopy (SERS) because of their ability to focus light in sub-diffraction-limited area, resulting in strong field enhancement. The field enhancement depends critically on the gap spacing of optical antennas. Current nanofabrication techniques such as focused ion beam milling and electron beam lithography are limited by poor uniformity and reproducibility as the dimension decreases below 10 nm, making it difficult to fabricate optical antennas with well-defined sub-10 nm gap spacing. In this project, we report on the...

Atomically-thin nature of graphene nanopores make it possible to sequence single DNA molecules with base-pair resolution. However, conventional approaches to fabricate nanopores on graphene require expensive and sophisticated process such as electron beam sculpting/drilling. Here, we report a simple single-step fabrication for creating graphene nanopores with integrated plasmonic nanoantenna by photothermal effect of gold nanorods. Tunability of nanopore dimensions and optical properties of plasmonic nanoantennas has been demonstrated by controlling laser fluence. The optical...

We developed an optical phased array incorporating a single-layer high-index-contrast sub- wavelength grating (HCG) for 2D beamsteering. There are a number of other approaches for optical phased arrays such as liquid-crystal-based phased arrays and microelectromechanical system (MEMS) phased array. Switching of liquid-crystal based phased arrays typically takes on the order of milliseconds. Arrays of MEMS mirrors moving perpendicular to the substrate are usually made of silicon so that a metal-coated layer is required on top, resulting in thermal induced stress when very high optical...

The wavelength selective switch (WSS) is a key enabling component for many optical circuit switching (OCS) architectures, which have the potential to allow datacenters to continue scaling beyond the cost and power efficiency constraints of current electrical networks. The applicability of these OCS networks in real-world datacenters is highly dependent on the speed and optical loss of the WSS elements. We have demonstrated a grating-based WSS in silicon photonics that improves on these metrics and allows greater integration potential relative to previously demonstrated MEMS-based WSS...