Type: 
Colloquium
Date-Time: 
Monday, February 6, 2012 - 16:00 to 17:00
Location: 
Weniger 153
Event Speaker: 
Dr. Ahmet Ali Yanik, Harvard Medical School
Local Contact: 
Tate
Abstract: 

Nanoplasmonic devices, with a unique ability to slow down, localize, and manipulate photons below sub-wavelength dimensions, have the potential to reinvent most of the known optical phenomena by boosting light-matter interactions by orders of magnitude in strength. The last decade has seen an explosion of research in the field of plasmonics for a wide range of applications, from information technology, to light harvesting, and biophotonics. In this talk, I will mainly focus on nanoplasmonics for life sciences and point-of-care diagnostics. However, the concepts and physical processes leading to enhanced light-matters interactions are equally applicable to other fields. In my talk, I will show how the principles and methods of nanoscale physics can be applied to real world problems. Using a bottom-up approach, I will bring concepts and techniques from multiple disciplines (nanophotonics, nanofabrication, and nano-biotechnology/microfluidics) to fundamental limitations.
In the first part of my talk, I will introduce an ultrasensitive infrared nanospectroscopy technique for conformational dynamics of proteins at few molecule levels. Conformational dynamics of proteins is one of the most critical components of life-sustaining biomolecular processes. However, the small intrinsic absorption cross-section of IR active modes of proteins has been a fundamental limitation in absorption spectroscopy. I will demonstrate 105 fold signal enhancements in the vibrational signatures of proteins by using the collective excitation of plasmonic nanoantenna arrays leading to unprecedented near field enhancements and record low zepto-mole detection limits. I will also show how the integration of our spectroscopic technique with optical fiber surfaces can achieve a real-time tissue biopsy in the human body to eliminate the need for current surgical approaches.
In the second part of the talk, I will introduce an optofluidic-nanoplasmonic biosensor merging nanofluidics and biosensing to overcome fundamental mass transport limitations. I will introduce the extra-ordinary light transmission effect through subradiant plasmonic resonances and demonstrate ultrasensitive biosensors with detection limits surpassing the gold standard for surface plasmon sensors. Furthermore, I will introduce a novel sensing scheme which enables label-free detection of biomarker proteins “with the naked eye” using plasmonic analogs of atomic Fano resonances. I will conclude my talk by discussing a real world application of our plasmonic sensors for the detection of live and intact viruses in biological media at medically relevant low concentrations. ________________________________________________________________

Ahmet Ali Yanik is a senior research associate in The Center for Engineering in Medicine at Harvard University Medical School and Massachusetts General Hospital. He received his Ph.D. degree in 2007 from the Department of Physics at Purdue University, under the supervision of Prof. Supriyo Datta.