Abstract
Previous femtosecond experiments have shown that a silicon surface becomes highly reflective1,2. and microscopically disordered3 in less than one picosecond following femtosecond pulsed excitation above a threshold fluence of approximately 0.1 J/cm2. The present experiment investigates the temperature rise of crystalline silicon excited below the threshold for melting through time-resolved measurements of refractive index changes in a submicron silicon film, and resolves a delay of tens of picoseconds in semiconductor lattice heating4. This technique5,6 relies upon the well characterized temperature dependence7 of the refractive index n + ik of silicon in the wavelength range between the indirect (1.15 eV) and direct (3.0 eV) band gaps. The temperature dependence of the index results from a downward shift of the direct band edge of silicon caused by renormalization of the band energy by the electron-phonon interaction, with a small contribution from lattice thermal expansion.8
© 1986 Optical Society of America
PDF ArticleMore Like This
A. MARCO MALVEZZI, N. BLOEMBERGEN, C. Y. HUANG, and H. KURZ
TULL5 International Quantum Electronics Conference (IQEC) 1986
M. C. DOWNER and C. V. SHANK
TUE2 Conference on Lasers and Electro-Optics (CLEO:S&I) 1985
K. Bohnert, H. Kalt, Thomas F. Boggess, Arthur L. Smirl, and R. Y. Loo
WE1 International Conference on Ultrafast Phenomena (UP) 1986