CUNY Advanced Science Seminar Series
Steven Cundiff 's primary research interest is in the general area of ultrafast optics. His lab's research areas includes the use of ultrafast pulses to study light-matter interactions, as well as their production and manipulation.The primary tool for studying light-matter interaction is multidimensional coherent spectroscopy, which the lab is currently applying to both semiconductor nanostructures and atomic vapors. The lab is also working on developing a new type of mode-locked fiber laser to produce ultrafast pulses and on manipulating them by pushing pulse-shaping techniques to their ultimate limit in terms of spectral resolution.
The concept of multidimensional Fourier transform spectroscopy originated in NMR where it enabled the determination of molecular structure. In either NMR or optics, a sample is excited by a series of pulses. The key concept is to correlate what happens during multiple time periods between pulses by
taking a multidimensional Fourier transform. The presence of a correlation, which is manifest as an off-diagonal peak in the resulting multidimensional spectrum, indicates that the corresponding resonances are coupled. Migrating multidimensional Fourier transform spectroscopy to the infrared and visible regimes is difficult because of the need to obtain full phase information about the emitted signal and for the phase difference between the excitation pulses to be stable and precisely incremented. I will give an introduction to optical two-dimensional coherent spectroscopy and then present our use of it to study optical resonances in semiconductor nanostructures. In quantum wells, our results show that many-body effects dominate the light-matter interaction for excitons in semiconductors and provide a rigorous and quantitative test of the theory. In quantum dots, there is inhomogeneous broadening due to size dispersion, however two-dimensional coherent spectroscopy can make size-resolved measurements without the need to isolate individual quantum dots. The understanding of how semiconductor nanostructures interact with light is critical for their application in photonics.
The Office of the Vice Chancellor for Research presents the CUNY Advanced Science Seminar (CASS) series focusing on five key and emerging science flagship disciplines at CUNY: nanoscience, photonics, environmental science, structural biology, and neuroscience. The seminars feature leaders in these fields, who spend a day at CUNY and meet with faculty and students. These disciplines are the focus of the CUNY Advanced Science Research Center (ASRC), which is scheduled to open in 2014. For more information please visit the ASRC website
The Fall 2013 series will take the form of lunchtime seminars. Lunch will be provided.
Friday March 14, 2014, 12:30-2:00pm
Optical Two-Dimensional Coherent Spectroscopy of Semiconductor Nanostructures
Steven T. Cundiff, University of Colorado, Boulder
Shepherd Hall, Room 95, The City College of New York
Click HERE to register