Seminar on
Modern Optics and Spectroscopy


Katherine Stone, MIT

"Multi-excitonic coupling in semiconductor nanostructures studied by multidimensional electronic Fourier transform spectroscopy"

April 8, 2008

12:00 noon - 1:00 p.m. Grier Room 34-401


Abstract:

Ultrafast excitation of solids creates coherent superpositions of correlated many-particle states. For electronic excitations, important high-order many-body correlations may contribute strongly to signals measured in nonlinear spectroscopy, but often the contributions are highly convolved with those from lower-order correlations. These high-order correlations are often involved in coherent control schemes for quantum information processing, accessing exciton spin coherence and controlling electromagnetically induced transparency in semiconductors. Two-dimensional Fourier Transform spectroscopy has revealed vibrational or electronic coupling in a variety of condensed phase systems. In order to isolate the high-order correlations in nonlinear signals from semiconductor quantum wells we employ a Two-quantum 2D electronic FTS technique that is based on spatiotemporal pulse shaping. This is the optical analogue of multiple-quantum techniques used routinely in 2D NMR spectroscopy. We are able to isolate and record direct observations of the many-body dynamics in a condensed phase system that are beyond a mean-field approximation.

TUESDAYS, 12:00-1:00, GRIER ROOM (34-401)
Refreshments served following the seminar

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Co-sponsored by the George R. Harrison Spectroscopy Laboratory,
the Department of Electrical Engineering and Computer Science and
the School of Science, Massachusetts Institute of Technology.