Author Affiliations

Yici Guo,^* Feng Liu,^* N. Zhadin,^* P. P. Ho,^* H. Savage,^** D. Harris,^** P. Sacks,^** S. Schantz,^** and R. R. Alfano^*,$

^*Institute for Ultrafast Spectroscopy and Lasers and New York State Center for Advanced Technology for Ultrafast Photonic Materials and Applications Departments of Electrical Engineering and Physics The City College of New York and Graduate School of The City University of New York New York, New York 10031

^**Memorial Sloan Kettering Cancer Center 425 East 67 Street, New York, N.Y. 10021

^$Corresponding Author: Prof. R. R. Alfano, Phys. Dept., Rm. J419, Institute for Ultrafast Spectroscopy and Lasers, City Collage of New York, 138^th St. and Convent Ave. N.Y. 10031. Tel: (212) 650 6960, 5533 Fax: (212) 650 5530