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Terahertz Spectroscopic Polarimetry and the Quest for THz Vibrational Circular Dichroism

Dr. Charles Schmuttenmaer, Yale University

Thursday, March 21, 2013
3:30 p.m.–4:30 p.m.
Sloan Auditorium

Abstract:
Professor Schuttenmaer will describe a new method to fully characterize the polarization state of every spectral component present in a time-domain THz pulse.  We have characterized a series of lithographically defined chiral metal spirals of opposite handedness to highlight these new capabilities.  It requires only the addition of a rotating polarizer in an existing THz time-domain spectrometer, and is akin to the familiar rotating analyzer method used in spectroscopic ellipsometers.

He will also describe recent progress toward the goal of measuring THz vibrational circular dichroism (VCD) spectra of organic molecular crystals.  Mid-infrared VCD studies of chiral molecules over the last three decades have proven to be a powerful tool for assigning IR spectra, particularly with regard to their absolute stereochemical configuration.  However, there has not yet been a broadband THz measurement of optical activity of any sort reported for molecular or biomolecular systems.  That is the goal.

Bio:
Charles A. Schmuttenmaer was born in Oak Park, IL in the USA.  He received a B.S. degree in chemistry from the University of Illinois, Urbana-Champaign in 1985, and a Ph.D. degree in chemistry from the University of California, Berkeley in 1991.  He was a Postdoctoral Fellow at the University of Rochester.  In 1994, he joined Yale University, New Haven, CT, where he is currently a Professor of Chemistry.  He is a pioneer in development and applications of terahertz (THz) spectroscopy.  Prof. Schmuttenmaer is a member of the American Chemical Society, the American Physical Society, the Optical Society of America, and the American Association for the Advancement of Science. 

His current research interests include novel applications of time-resolved THz spectroscopy (TRTS) and THz time-domain spectroscopy (THz-TDS).  In particular, he has exploited the unique features of TRTS to characterize the efficiency of electron injection in dye-sensitized solar cells (DSSCs), which are a promising alternative to silicon photovoltaic solar cells, as well as transient photoconductivity in semiconductors, quantum dots, nanoparticles, and nanotubes.  He is a founding member of the Yale Green Energy Consortium (www.chem.yale.edu/~green).  A second major research area involves THz-TDS coupled with high level ab initio quantum chemical calculations to probe and understand the low-frequency collective vibrational modes in organic molecular crystals.  A primary goal is to experimentally measure and theoretically compute the optical activity of these low-frequency modes.