1. a Physics Department , Brooklyn College of the City University of New York , Brooklyn , New York , 11210 , USA
2. d Graduate School and University Center of the City University of New York , New York , New York , 10036 , USA
3. b Institute for Ultrafast Spectroscopy and Lasers, Electrical Engineering and Physics Departments, City College of the City University of New York , New York , New York , 10031 , USA
4. e Hamamatsu Photonics K.K., Central Research Laboratory , Shizuoka , 434 , Japan
5. c Coordinated Science Laboratory and Materials Research Laboratory , 1045 S. Goodwin Avenue University Of Illinois At Urbana-Champaign , Urbana , Illinois , 61801 , USA
6. f Texas Instruments , Dallas , Texas , 75262 , USA