Materials Science and Engineering Seminar Series: Henry Du
Photonic Crystal Fiber as an Optofluidic Platform for Surface-Enhanced Raman Scattering-Based Sensing
Professor and Chair
Department of Chemical Engineerng and Materials Science
Stevens Institute of Technology
This presentation will focus on the strategy and the methods to integrate surface-enhanced Raman scattering (SERS) functionality with the emerging photonic crystal fiber (PCF) technology in order to achieve a robust optofluidic sensing platform for ultra-trace chemical detection and molecular fingerprinting. SERS is referred to as the orders of magnitude enhancement of the Raman scattering cross section in the presence of a metallic nanostructure. PCF is a class of specialty optical fibers with axially aligned air holes along the fiber length. Key to realizing SERS-active silica-based PCF platform lies in the controlled immobilization of Ag nanoparticles in the fiber air channels. Highlighted in the presentation will be (1) our theoretically study of the interaction of the evanescent field with the nanoparticles immobilized on the guiding core for proper selection of their size and the coverage density in consideration of the resultant light scattering and absorption losses; (2) synthesis of colloids of Ag nanoparticles and their general characteristics; (3) immobilization of the Ag nanoparticles inside of the PCF using self-assembled polyelectrolyte monolayers as intermediate; and (4) demonstrated feasibility of SERS-active PCF platform with measurements of model analytes in aqueous solution as examples.
About the Speaker
Henry Du is Professor and Director of Department of Chemical Engineering and Materials Science at Stevens Institute of Technology, Hoboken, New Jersey. Du holds a doctoral degree in Ceramic Science from Penn State. His primary research interests include photonic crystal fibers as novel sensing platform, molecular and nanoscale surface functionalization, targeted delivery and release of drugs, and biomedical imaging. His research has been funded by NSF, AFOSR, NASA, ONR, US Army, Bell Laboratories, and Honeywell International. Dus work has resulted in nearly one hundred publications and numerous invited talks in the US and abroad. He is a recipient of Jess Davis Memorial Award and Deans Research Award at Stevens. He is a member of the American Ceramic Society, the Materials Research Society, and SPIE. He also serves as Associate Editor for the Journal of the American Ceramic Society and a Chair of SPIEs annual fiber-optic sensing conference series.