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For instance, the laser, superconductivity and superfluidity are examples of highly coherent quantum systems whose effects are evident at the macroscopic scale. The macroscopic quantum coherence (off-diagonal long-range order, ODLRO) [ 25 ] [ 26 ] for superfluidity, and laser light, is related to first-order (1-body) coherence/ODLRO, while ...
For an electromagnetic wave, the coherence time is the time over which a propagating wave (especially a laser or maser beam) may be considered coherent, meaning that its phase is, on average, predictable. In long-distance transmission systems, the coherence time may be reduced by propagation factors such as dispersion, scattering, and diffraction.
Multimode helium–neon lasers have a typical coherence length on the order of centimeters, while the coherence length of longitudinally single-mode lasers can exceed 1 km. Semiconductor lasers can reach some 100 m, but small, inexpensive semiconductor lasers have shorter lengths, with one source [4] claiming 20 cm. Singlemode fiber lasers with linewidths of a few kHz can have coherence ...
The back-formed verb "to lase" is frequently used in the field, meaning "to give off coherent light," especially about the gain medium of a laser; [16] when a laser is operating, it is said to be "lasing". [17] The terms laser and maser are also used for naturally occurring coherent emissions, as in astrophysical maser and atom laser. [18] [19]
For instance, a coherent state describes the oscillating motion of a particle confined in a quadratic potential well (for an early reference, see e.g. Schiff's textbook [3]). The coherent state describes a state in a system for which the ground-state wavepacket is displaced from the origin of the system.
Coherent control is a quantum mechanics-based method for controlling dynamic processes by light.The basic principle is to control quantum interference phenomena, typically by shaping the phase of laser pulses.
Coherent state are quantum mechanical states that have the maximal coherence and have the most "classical"-like behavior. A coherent state is defined as the quantum mechanical state that is the eigenstate of the electric field operator E ^ + {\displaystyle {\hat {E}}^{+}} .
In physics, coherent backscattering is observed when coherent radiation (such as a laser beam) propagates through a medium which has a large number of scattering centers (such as milk or a thick cloud) of size comparable to the wavelength of the radiation. Propagation of two rays in a random medium.