Sound amplification by stimulated emission of radiation was first experimentally demonstrated in the Gigahertz range in 2009. Announced in 2010, two independent groups came up with two different devices that produce coherent phonons at any frequency in the range megahertz to terahertz. One group from the University of Nottingham consisted of A.J. Kent and his colleagues R.P. Beardsley, A.V. Akimov, W. Maryam and M. Henini. The other group from the California Institute of Technology (Caltech) consisted of Ivan S. Grudinin, Hansuek Lee, O. Painter and Kerry J. Vahala from Caltech implemented a study on Phonon Laser Action in a tunable two-level system. The University of Nottingham device
Sound amplification by stimulated emission of radiation optics. Basic understanding of the SASER development requires the evaluation of some proposed examples of SASER devices and SASER theoretical schemes. In this proposed theoretical scheme, the active medium is a liquid dielectric (e.g. ordinary distilled water) in which dispersed particles are uniformly distributed. Means of electrolysis cause gas bubbles that serve as the dispersed particles. A pumped wave excited in the active medium produces a periodic variation of the volumes of the dispersed particles (gas bubbles). Since, the initial spatial distribution of the particles is uniform, the waves emitted by the particles are added with different phases and give