Nano-Optics for Highly Localized EM Fields and Some Applications

This presentation describes studies of optical phenomena at the nanoscale for coupling electromagnetic waves into bright, sub-diffraction-limited spots. In particular, we investigate optical and infrared antennas designed to strongly resonate with radiation. The gain of the antenna is further increased using various strategies to enhance resonances or arranging antenna arrays such that antenna apertures are strongly coupled via the magnetic field. Numerical and experimental studies have shown that these antennas can provide transmission many orders of magnitude higher than an aperture with a comparable size, can absorb the incoming radiation completely, and can be highly sensitive to polarization directions. The role of plasmonics or plasmonic resonant effect in some particular metal structures will also be discussed. We demonstrate that these high-gain antennas can be used in a wide range of applications, including parallel nanolithography, ultra-high density data storage, selective radiation surfaces, and enhanced, polarizationsensitive sensing in novel 2D materials. This presentation will also discuss some of our other research efforts including thermal transport in two-dimensional materials and transport of the surface spin states in thin film topological insulators.

Biography

Xianfan Xu is James J. and Carol L. Shuttleworth Professor of Mechanical Engineering at Purdue University with a courtesy appointment in Electrical and Computer Engineering. He obtained his M.S. (1991) and Ph.D. (1994) degrees in Mechanical Engineering from the University of California, Berkeley. His current research is focused on ultrafast and nanoscale optics and their applications in energy transfer/conversion studies and nanomanufacturing. He is the recipient of the ASME Heat Transfer Memorial Award. He is a Fellow of the American Society of Mechanical Engineers, SPIE, and Optical Society of America. He currently serves as Associate Editor for Optics Express and Scientific Reports.