Sound amplification by stimulated emission of radiation "acoustic laser" or "sound laser". SASERs could have wide applications. Apart from facilitating the investigation of terahertz-frequency ultrasound, the SASER is also likely to find uses in optoelectronics (electronic devices that detect and control light—as a method of transmitting a signal from an end to the other of, for instance, fiber optics), as a method of signal modulation and/or transmission. Such devices could be high precision measurement instruments and they could lead to high energy focused sound. Using SASERs to manipulate electrons inside semiconductors could theoretically result in terahertz-frequency computer processors, much faster than the current chips. This concept can
Stimulated emission to the number of atoms in the lower state, "N". Einstein showed that the coefficient for this transition must be identical to that for stimulated emission: Thus absorption and stimulated emission are reverse processes proceeding at somewhat different rates. Another way of viewing this is to look at the "net" stimulated emission or absorption viewing it as a single process. The net rate of transitions from "E" to "E" due to this combined process can be found by adding their respective rates, given above: Thus a net power is released into the electric field equal to the photon energy "hν"