Generation of coherent LO phonons in GaAs/AlGaAs MQW by the impulsive stimulated Raman scattering

Summary form only given. We show that the generation mechanism of coherent phonons in a quasi two dimensional GaAs/AlGaAs multiple quantum well structure is mainly the impulsive stimulated Raman scattering (ISRS). This is in sharp contrast with bulk GaAs, where ISRS plays only a minor role, if any. In addition, interference between the allowed and the forbidden Raman scattering plays an important role.