Coherent Excitation of the Optic Phonon in Si: Transiently Stimulated Raman Scattering with aFinite-Lifetime Electronic Excitation

Authors

D. Mark Riffe, Utah State UniversityFollow
A. J. Sabbah

Document Type

Article

Journal/Book Title/Conference

Physical Review B

Volume

76

Issue

8

Publication Date

8-17-2007

First Page

085207-1

Last Page

085207-12

Abstract

Using 28-fs, 800-nm laser pulses we have coherently excited and subsequently probed, with time-dependent reflectivity, the Si zone-center optic phonon. The phonon-induced reflectivity change ΔR∕R is well described by the response of an underdamped oscillator: ΔR∕R∝ exp(−t∕τ_ph) cos(2πt∕T_ph+ϕ). The measured phase ϕ indicates that transiently stimulated Raman scattering (TSRS) is responsible for the coherent-phonon generation: our results are in good agreement with a recent theory of TSRS for opaque materials [ T. E. Stevens et al. Phys. Rev. B 65 144304 (2002)] when we extend the theory to include the finite lifetime of the excited charge density that couples to the oscillation. We also discuss previous experimental results on Te, Bi, Sb, Si, and Ge in light of this extended theory. Additionally, our measured period T_ph and decay time τ_ph of the Si coherent oscillation are consistent with carrier-density-dependent Raman-scattering measurements.

Comments

Published by American Physical Society in Physical Review B. Publisher PDF is available for download through link above.

Recommended Citation

"Coherent Excitation of the Optic Phonon in Si: Transiently Stimulated Raman Scattering with a Finite-Lifetime Electronic Excitation," D. M. Riffe and A. J. Sabbah, Phys. Rev. B 76, 085207 (2007).