Engineered Highly Efficient Nanofocusing Plasmonic Waveguides

Scientific and commercial applications of optical nanofcousing devices have attracted a lot of research efforts in recent years. Sub-diffraction-limited microscopy, nano-photolithography, tipbased nanofabrication, and heat-assisted magnetic recording (HAMR) for achieving data density beyond 1 Tbits/in^2 are a few examples. To realize these applications, nanofocusing devices must be able to confine light into sub-50-nm space (sub-20nm for HAMR applications) at high efficiency. Previously, researchers have achieved nanofocusing using scanning-tunnelingmicroscope (STM) tips, tapered plasmonic pins, enhanced transmission apertures, and tapered fiber probes [1-4].