The fields of plasmonics and metamaterials have seen significant growth in recent years, due to the interest in creating novel photonic devices as well as exploring the physics behind light-matter interaction at the nanoscale. Much of this work has been done in the visible spectral range with traditional metals such as gold and silver. However, the mid-infrared spectral range offers much in the way of applied research in health and the environment, security and defense, communication, and sensing. While it is easy to scale plasmonic device geometries to the infrared, finding materials with the requisite optical properties is more difficult.
In this talk, I will discuss my recent work using new materials, specifically heavily-doped InAs grown by molecular beam epitaxy, for infrared plasmonic devices. I will explain the advantages of these new materials over traditional plasmonic materials in the infrared and demonstrate that they act as near-perfect Drude metals with tunable optical properties which can also be integrated with existing semiconductor optoelectronic devices. I will then exhibit the utility of such materials in the fabrication of nanoantennas, which allow for confinement of the electric field in nano-scale volumes and thus enhanced interaction of long-wavelength infrared light with nano scale particles. These structures have been demonstrated to give improved sensing of the vibrational modes of analytes on the surface. Layered semiconductor samples show wavelength-specific near-perfect absorption due to the excitation of highly-confined negative-index surface plasmon polaritons in a plasmonic crystal structure, one of the first demonstrations of this phenomenon in the infrared.
Stephanie Law received her B.S. in Physics from Iowa State University in May, 2006 where she grew and measured single crystals of novel materials. She earned her Ph.D. in Physics from the University of Illinois Urbana Champaign in May, 2012 using a technique called molecular beam epitaxy (MBE) to study the proximity effect between superconductors and semiconductors. As a postdoc, her work involves using MBE to grow semiconductor films, dots, and other structures to investigate novel materials and device structures for mid-infrared plasmonics, sensors, and emitters.
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University of Illinois at Urbana-Champaign