Time resolved reflectivity of bismuth thin film evaporated on a silicon substrate is measured by an 80 femtosecond (fs) laser at a center wavelength of 800 nm. The reflectivity data reveal that coherent optical phonons (A1g) near 2.9 THz (1 THz = 1012 Hz) are excited by the 80 fs laser pulses. Analyses of the reflectivity data reveal key parameters related to electron and phonon dynamics, including phonon excitation and de-phasing and electron-phonon energy coupling. It is also found that the phonon frequency peaks are red-shifted and broadened at higher laser fluences. We also show that the phonon oscillation can be manipulated by specifically designed ultrafast pulse trains with different pulse separation times.
- Nanotechnology Institute
Coherent Phonon Excitation by Ultrafast Pulse Trains
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Wu, AQ, & Xu, X. "Coherent Phonon Excitation by Ultrafast Pulse Trains." Proceedings of the 2007 First International Conference on Integration and Commercialization of Micro and Nanosystems. First International Conference on Integration and Commercialization of Micro and Nanosystems, Parts A and B. Sanya, Hainan, China. January 10–13, 2007. pp. 955-957. ASME. https://doi.org/10.1115/MNC2007-21591
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