Plasmonic Interferometry for Photovoltaics and Biosensing Applications

Description
BSTRACT: Surface Plasmon Polaritons (SPPs) are fluctuations of the free electron density in metals coupled to electromagnetic waves.  SPPs at optical frequencies show a significant momentum mismatch with respect to the light incident on a flat metal/dielectric interface, therefore coupling strategies generally rely on prisms (Kretschmann configuration) or metal gratings to excite them. 
In this talk I will show alternative methods to generate SPPs at optical frequencies using light diffraction by individual nanocorrugations etched in metal films. In particular, I will show how nanometer scale slits, grooves and holes can be used as efficient, localized sources of SPPs.
Spatial localization of the source of SPPs allows for control of the SPP propagative phase, thus enabling researchers to perform "plasmonic interferometry," i.e. optical interferometry at the nano- and micro- scale using SPPs as the interfering waves.
By properly varying the nanoscatterer separation distance and in-plane distribution, the optical interference of SPPs can be spatially modulated and spectrally tuned. This property, together with the highly confined nature of SPPs, can be used to enhance the optical absorption in thin film solar cells and improve the sensitivity to chemical analytes in biosensors employing plasmonic interferometry.

Biosketch: Domenico Pacifici joined Brown University in 2009 as an Assistant Professor in the School of Engineering. He received his Laurea (2000) and Ph.D. (2004) in Physics, both summa cum laude, from the University of Catania in Italy, where he studied the optical, structural and electrical properties of silicon quantum dots and their interaction with rare-earth ions for a silicon-based Microphotonics, under the supervision of Prof. Francesco Priolo. Prior to joining Brown, Professor Pacifici spent four years as a senior postdoctoral scholar in the Department of Applied Physics at the California Institute of Technology, under the supervision of Prof. Harry A. Atwater.
Prof. Pacifici and his group are currently leading research projects involving the use of photons and surface plasmons in nanostructured materials for optical communication, sensing and energy-harvesting applications. Recently, the Pacifici Group has demonstrated: (1) plasmonic concentrators for broad-band enhanced absorption in ultra-thin film solar cells, and (2) high-throughput biochemical sensors using plasmonic interferometers integrated on-chip for detection of extremely low glucose concentrations, typically found in saliva, for non-invasive glucose screening.  
Prof. Pacifici has been awarded the Richard B. Salomon Faculty Research Award (2010), established to “support excellence in scholarly work by providing funding for selected faculty research projects deemed to be of exceptional merit.” He received a Dedicated Faculty Award from Brown University’s School of Engineering and Tau Beta Pi (2012), for “enriching the undergraduate education experience and demonstrating superior teaching, dedication, and involvement both in and out of the classroom.” He is recipient of a Henry Merritt Wriston Fellowship (2013) for “his contributions to excellence in teaching and for the devotion to the intellectual development of both graduate and undergraduate students.” In 2013 Prof. Pacifici received a Seed Grant to pursue collaborative research activity with the Department of Physics at Brown University. The Pacifici group is regularly funded by NSF, the National Science Foundation (CBET and DMR divisions), by ONR, the Office of Naval Research, and recently by JDRF, the Juvenile Diabetes Research Foundation.
Organised by Salvo Mirabella