Optical Cavity

An optical cavity or optical resonator is an arrangement of mirrors that forms a standing wave cavity resonator for light waves. Optical cavities are a major component of lasers, surrounding the gain medium and providing feedback of the laser light. They are also used in optical parametric oscillators and some interferometers. Light confined in the cavity reflect multiple times producing standing waves for certain resonance frequencies. The standing wave patterns produced are called modes; longitudinal modes differ only in frequency while transverse modes differ for different frequencies and have different intensity patterns across the cross section of the beam.

Different resonator types are distinguished by the focal lengths of the two mirrors and the distance between them. (Flat mirrors are not often used because of the difficulty of aligning them to the needed precision.) The geometry (resonator type) must be chosen so that the beam remains stable (that the size of the beam does not continually grow with multiple reflections). Resonator types are also designed to meet other criteria such as minimum beam waist or having no focal point (and therefore intense light at that point) inside the cavity.

Optical cavities are designed to have a large Q factor; a beam will reflect a very large number of times with little attenuation. Therefore the frequency line width of the beam is very small indeed compared to the frequency of the laser.

Read more about Optical Cavity:  Resonator Modes, Resonator Types, Spherical Cavity, Stability, Practical Resonators, Optical Delay Lines

Other articles related to "optical, optical cavity, cavity":

Laser Diode - Theory of Operation
... Another method of powering some diode lasers is the use of optical pumping ... This means that stimulated emission causes gain in an optical wave (of the correct wavelength) in the injection region, and the gain increases as the ... As in other lasers, the gain region is surrounded with an optical cavity to form a laser ...
Index Of Physics Articles - C
... Cat state Catadioptric sensor Catapult effect Catastrophic optical damage Catherine Bréchignac Cathodoluminescence Cathodoluminescence microscope Catoptrics Cauchy's equation Cauchy horizon Cauchy ... shape resonance Core/Shell Semiconductor Nanocrystals Core (optical fiber) Core electron Core–mantle boundary Coriolis effect Coriolis field Coriolis–Stokes force Corium (nuclear reactor ... Sciences and Education Corner reflector Cornering force Corona Corona (optical phenomenon) Corona discharge Corona poling Coronal mass ejection Coronal radiative losses Coronal seismology Corpuscular theory of light ...
Optical Cavity - Optical Delay Lines
... Optical cavities can also be used as multipass optical delay lines, folding a light beam so that a long path-length may be achieved in a small space ... A plane-parallel cavity with flat mirrors produces a flat zigzag light path, but as discussed above, these designs are very sensitive to mechanical disturbances and walk-off ... The rotation of the beam inside the cavity alters the polarization state of the beam ...

Famous quotes containing the word optical:

    It is said that a carpenter building a summer hotel here ... declared that one very clear day he picked out a ship coming into Portland Harbor and could distinctly see that its cargo was West Indian rum. A county historian avers that it was probably an optical delusion, the result of looking so often through a glass in common use in those days.
    —For the State of New Hampshire, U.S. public relief program (1935-1943)