Sound amplification by stimulated emission of radiation a mathematical calculation of the starting conditions. Bubbles with resonance frequencies close to the pump frequency make the main contribution to the gain of the useful mode. In contrast, the determination of the starting pressure in ordinary lasers is independent from the number of radiators. The useful mode grows with the number of particles but sound absorption increases at the same time. Both these factors neutralize each other. Bubbles play the main role in the energy dispersion in a SASER. A relevant suggested scheme of sound amplification by stimulated emission of radiation using gas bubbles as the active medium was
Sound amplification by stimulated emission of radiation energy of the lattice can take discrete values for every excitation. Every one of this "excitation packages" is called phonon. An electron does not stay in an excited state for too long. It readily releases energy to return to its stable low energy state. The electrons release energy in any random direction and at any time (after their excitation). At some particular times, some electrons get excited while others lose energy in a way that the average energy of system is the lowest possible. By pumping energy into the system we can achieve a population inversion. This means that there