Semiconductor quantum dot superlattice for coherent acoustic phonon emission

We present a novel concept of using quantum dot superlattices for coherent acoustic phonon emission. Coherent lattice wave generation is proposed by collective dot vibrations in a self-assembled quantum dot array, where superlattice structure acts as a phonon resonator. The dots vibrations are synchronized by an external electric field. The proposed scheme has advantage of low phonon scattering rate in quantum dots, that enables generating high intensity phonon beams at low amplitude of the pumping electric field. The advantage is illustrated by numerical simulations carried out for Si/Ge superlattice. The proposed scheme may find many phonon applications, such as for local temperature control, phonon assisted optical transition enhancement, and characterization of low-dimensional structures.