Sound amplification by stimulated emission of radiation Such values approach the electric puncture intensity of liquid dielectrics. Hence, a study proposes a SASER scheme without this limitation. The pumping is created by radial mechanical pulsations of a cylinder. This cylinder contains an active medium—a liquid dielectric with gas bubbles. The radiation emits through the faces of the cylinder. A proposal for the development of a phonon laser on resonant phonon transitions has been introduced from a group in Institute of Spectroscopy in Moscow, Russia. Two schemes for steady stimulated phonon generation were mentioned. The first scheme exploits a narrow - gap indirect semiconductor or analogous indirect gap
Sound amplification by stimulated emission of radiation of Nottingham. Wannier-Stark effect, exists in superlattices. Electron states in quantum wells respond sensitively to moderate electric fields either by the quantum confined Stark effect in the case of wide barriers or by Wannier-Stark localization in the case of a superlattice. Both effects lead to large changes of the optical properties near the absorption edge, which are useful for intensity modulation and optical switching. Namely, in a mathematical point of view, if an electric field is applied to a superlattice the relevant Hamiltonian exhibits an additional scalar potential. If an eigenstate exists, then the states corresponding to wave functions are