Time-resolved Raman scattering measurements are made by using 110 fs laser pulses in germanium at the initial carrier density of 3×${10}^{18}$ ${\mathrm{cm}}^{\mathrm{-}3}$. Intensity build-up is clearly observed for the Raman scattering due to photoexcited electrons in L valleys and is quantitatively analyzed in terms of the theory on the electronic light scattering from a multicomponent electron gas. We show that photoexcited electrons initially created in the Γ valley are scattered into L valleys with a time constant of 1.2±0.1 ps.

• Received 29 July 1993

DOI:https://doi.org/10.1103/PhysRevLett.71.1935