Sound amplification by stimulated emission of radiation the lattice levels, until they escape from the lattice structure in a form of an ultrahigh frequency-phonon beam. Namely, a concerted emission of phonons can lead to coherent sound and an example of concerted phonon emission is the emission coming from quantum wells. This stands in similar paths with the laser where a coherent light can build up by the concerted stimulated emission of light from a lot of atoms. A SASER device transforms the electric potential energy in a single vibrational mode of the lattice (phonon). The medium where the amplification takes place, consists of stacks of thin layers
Sound amplification by stimulated emission of radiation leads to the appearance of an additional quasi-periodic wave. This wave is coupled with the spatial variation of the bubble density under the action of radiation pressure forces. Hence, the wave amplitude and the bubble density vary slowly compared with the period of the oscillations. In the theoretical scheme where the usage of resonators is essential, the SASER radiation passes through the resonator walls, which are perpendicular to the direction of propagation of the pump wave. According to an example of an electrically pumped SASER, the active medium is confined between two planes, which are defined by the solid walls