Date: Wednesday, January 31, 2018
Time: 11:00 AM to Noon
Location: CHTM, Room 101
Map to CHTM:
Parking passes are available at the receptionist desk.
Research progress in nanooptics and nanophotonics over the past several decades shows that nanoscale materials increase light-matter interaction dramatically and provide optical tunability simply by changing the dimension of the same material composition. These optical characteristics are desirable for harvesting energy of the broad solar spectrum, highly sensitive microscopy, spectroscopy, photodetection, photocatalysis, and many other optoelectronic applications. Our research utilizes nanoscale optical properties to overcome the fundamental resolution limit imposed by the diffraction property of light and achieve super-resolution near-field imaging, to investigate interface properties and interparticle interactions, and to drive and probe surface chemistry with highly sensitive in situ vibrational spectroscopy. In this presentation, representative results that illustrate each of these research activities will be discussed with particular emphasis on recent not yet published results. Plasmon-driven photochemical reactions will be discussed based on our recent exciting experimental observations, where the remarkable effects of surface ligands as well as simultaneous excitation of particle and molecular resonances are demonstrated. The results provide important insight into the mechanism of plasmon-driven surface photochemistry, and at the same time, indicate the hidden chemistry on metal surfaces, where looking at molecules based on their fluorescence is no longer a possibility. Plasmon enhanced exciton generation and temperature dependent emission enhancement will be discussed based on results obtained on epitaxial quantum dots and quantum well near-infrared emitters. Plasmonic interactions at touching or subnanometer coupling limit that leads to quantum mechanical phenomena will be highlighted as current and future research directions.
Terefe Habteyes is assistant Professor in the Department of Chemistry and Chemical Biology and member of the Center for High Technology Materials at the University of New Mexixo (UNM). He received his BS (1997) and MS (2000) both in Chemistry from Addis Ababa University, and his PhD in Chemistry in 2008 from the University of Arizona. From 2008 to 2012, he worked on the development of near-field scanning optical microscopy as well as on the design, fabrication and characterization of plasmonic materials as a University of California President’s postdoctoral fellow working at UC Berkeley, and the Molecular Foundry, Lawrence Berkeley National Lab, under the supervision of Profs. Leone and Alivisatos. He began his faculty position at UNM in August 2012. His research interests include super-resolution near-field optical imaging, exciton-plasmon interactions, plasmon enhanced surface photochemical reactions and self-assembly of nanomaterials. His research is supported by the NSF CAREER award program and the AFOSR.