1. Institute for Ultrafast Spectroscopy and Lasers, Department of Physics, The City College of the City University of New York, 160 Convent Avenue, New York, NY 10031 USA
2. Department of Physics, The City College and the Graduate Center of the City University of New York, 160 Convent Avenue, New York, NY 10031 USA
3. Department of Physics, Fairfield University, Fairfield, CT 06824 USA