Sound amplification by stimulated emission of radiation despite the difference in phonon and exciton dimensionalities. Phonon laser action has been stated in a wide range of physical systems (e.g. semiconductors). A 2012 publication from the Department of Applied Physics in California Institute of Technology (Caltech), introduces a demonstration of a compound micro-cavity system, coupled with a radio-frequency mechanical mode, which operates in close analogy to a two level-laser system. This compound micro-cavity system can also be called ""photonic molecule"". Hybridized orbitals of an electrical system are replaced by optical supermodes of this photonic molecule while the transitions between their corresponding energy levels are induced by a phonon
Stimulated emission resulting from the distribution of velocities in a gas at a certain temperature. This has a Gaussian shape and reduces the peak strength of the line shape function. In a practical problem the full line shape function can be computed through a convolution of the individual line shape functions involved. Therefore, optical amplification will add power to an incident optical field at frequency formula_17 at a rate given by The stimulated emission cross section is where Stimulated emission can provide a physical mechanism for optical amplification. If an external source of energy stimulates more than 50% of the atoms in