Abstract
We have demonstrated the generation of intense coherent longitudinal optical (LO) phonon oscillations with use of intersubband energy tuning by application of electric field. The coherent LO phonon in a GaAs/AlAs multiple quantum well was investigated in detail as a function of electric field by using a reflection-type pump-probe technique. In the case that the intersubband energy is tuned to the LO phonon energy of GaAs by the electric field owing to a quantum confined Stark effect, the amplitude of the coherent LO phonon is intensively enhanced by a factor of 23 in comparison with the amplitude in a low electric field regime. This enhancement is caused by the coupling between the coherent LO phonon and the longitudinal polarization due to the impulsive interference between excitons with different subbands.
- Received 6 April 2004
DOI:https://doi.org/10.1103/PhysRevB.70.233306
©2004 American Physical Society