Coherent multi-exciton dynamics in semiconductor nanostructures via two-dimensional Fourier transform optical spectroscopy

The Coulomb correlations between photoexcited charged particles in materials such as photosynthetic complexes, conjugated polymer systems, J-aggregates, and bulk or nanostructured semiconductors produce a hierarchy of collective electronic excitations (i.e. excitons, biexcitons, etc.) which may be harnessed for applications in quantum optics, light-harvesting, or quantum information technologies. These excitations represent correlations among successively greater numbers of electrons and holes, and their associated multiple-quantum coherences could reveal detailed information about complex many-body interactions and dynamics. However, unlike single-quantum coherences involving excitons, multiple-quantum coherences do not radiate and they have largely eluded direct observation and characterization. In this work, I present a novel optical technique, two-quantum two-dimensional Fourier transform optical spectroscopy, which allows direct observation of the dynamics of multiple-exciton states that reflect the correlations of their constituent electrons and holes. The approach is based on closely analogous methods in nuclear magnetic resonance, in which multiple phase-coherent fields are used to drive successive transitions such that multiple-quantum coherences can be accessed and probed. A spatiotemporal femtosecond pulse shaping technique has been used to overcome the challenge of control over multiple, noncollinear phase-coherent optical Fields in the experimental geometries that are used to isolate selected signal contributions through wavevector matching.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Stone, Katherine Walowicz

Advisor dc:contributor.advisor

• Keith A. Nelson.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/49554

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/49554