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
Sound amplification by stimulated emission of radiation a p-n transition. It has been mentioned that a quantum well is basically a potential well that confines particles to move in two dimensions instead of three, forcing them to occupy a planar region. In coupled quantum wells there are two possible ways for electrons and holes to be bound into an exciton: indirect exciton and direct exciton. In indirect exciton, electrons and holes are in different quantum wells, in contrast with direct exciton where electrons and holes are located in the same well. In a case where the quantum wells are identical, both levels have a two-fold degeneracy. Direct