UB - University at Buffalo, The State University of New York Chemical and Biological Engineering

Surface Plasmon Resonance Sensing at Surfaces with Nanostructured Topology

September 13, 2017

Amol Ajinkya Memorial Fund Lecture

Andrew C. Hillier

Iowa State University

The interaction of light with nanostructured objects, particularly those containing metals, can produce a variety of unique, interesting, and potentially useful optical phenomena. Examples include enhanced optical transmission through nanostructured metals, super focusing through nano-apertures, and optical waveguiding via nanoparticle chains. The origins of many of these optical phenomena can be traced to the excitation and propagation of surface plasmons at nanostructured metal objects. Notably, these surface plasmon effects have also been exploited in a variety of sensing applications. Nanostructure-based plasmonic sensing has been achieved with nanohole arrays, single nanometric holes, nanoslit arrays, and various diffractive nanostructures.

In this presentation, I will describe recent work from my group involving the construction and analysis of diffraction grating couplers for the excitation and sensing of surface plasmons. Gratings provide a unique combination of features that make them promising substrates for the construction of nanoscale optical elements and plasmonic devices. Notably, the ability to control the size (pitch and amplitude), shape (surface profile) and geometry (angle) of gratings allows precise control over the resulting plasmonic features, including the strength of coupling and the details of the optical response, including the shape and location of the optical features. Several examples will be discussed, using both experiment and optical modeling, to investigate the role of various surface features on plasmonic behavior of metal-coated gratings. Examples include enhanced optical transmission through metal-coated gratings, the development of ?chirped? diffraction gratings for detailed structural analysis, and the use of dispersion imaging to fully characterize the complexity of the optical response. The ability to combine grating-coupled surface plasmon resonance to other analytical techniques will also be described. Examples include SPR-based imaging of microarrays and grating-coupled SPR in combination with infrared and optical spectroscopy.

Biographical Sketch

Andrew C. Hillier is Professor and Reginald R. Baxter Endowed Department Chair of the Department of Chemical and Biological Engineering at Iowa State University. Dr. Hillier received his B.S. in chemical engineering from the University of Nebraska in 1990 and his Ph.D. in chemical engineering from the University of Minnesota in 1995. Following a postdoctoral appointment at the University of Texas at Austin working with Al Bard, he started his academic career at the University of Virginia, where he rose to rank of Associate Professor. While at Virginia, Hillier was a member of the Department of Chemical Engineering and the Center for Electrochemical Science and Engineering (CESE). In 2003, Hillier moved to Iowa State University to join the faculty of the Department of Chemical and Biological Engineering and the Department of Chemistry. At Iowa State, Hillier has been on the Executive Committee of the Institute for Combinatorial Discovery, Associate Scientist with the Ames Laboratory, the director of the W.M. Keck Laboratory for High Throughput Atom Scale Analysis, and is currently the Chair of the Department of Chemical and Biological Engineering. Hillier?s research interests include electrochemistry, fuel cells, thin film design and characterization, scanning probe microscopy, optical sensing at nanostructured surfaces, and atom probe tomography. Hillier has been recognized with several awards during his career, including the Camille and Henry Dreyfus New Faculty Award, a National Science Foundation Career Award, and a Young Investigator Award from the Office of Naval Research, and a Young Investigator Award by the Society of Electroanalytical Chemistry.

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