Sound amplification by stimulated emission of radiation the axes of the mirrors, it is possible for photons to repeat multiple reflections and force more and more photons to follow them producing an avalanche effect. The number of photons of this coherent laser beam increases and competes the number of photons perished due to losses. The basic necessary condition for the generation of a laser radiation is the population inversion, which can be achieved either by exciting atoms and inducing percussion or by external radiation absorption. A SASER device mimics this procedure using a source-pump to induce a sound beam of phonons. This sound beam propagates not in
Sound amplification by stimulated emission of radiation in the system leads to both the appearance of a backward wave and a dynamical instability of the system. Mathematical analyses have shown that two types of losses must be overcome for generation of oscillations to start. Losses of the first type are associated with the dispersion of energy inside the active medium and second type losses are due to radiation losses at the ends of the resonator. These types of losses are inversely proportional to the amount of energy stored in the resonator. In general, the disparity of the radiators does not play a role in any attempt of