Ring laser
Encyclopedia
A ring laser is a laser
in which the laser cavity has the shape of a ring. Light in ring lasers has two possible directions of propagation: clockwise and counter-clockwise.
Ring lasers are sometimes modified to allow only one direction of propagation by placing a device into the ring which leads to different losses for different propagation directions. For instance, this could be a Faraday rotator
combined with a polarizing element.
One type of ring laser design is a single crystal design, where light reflects around inside the laser crystal so as to circulate in a ring. This is the "monolithic crystal" design, and such devices are known as "non-planar ring oscillators" (NPROs) or MISERs. There are also ring fiber laser
s.
Ring lasers have several applications. Currently the most widespread application is the ring laser gyroscope
. If a ring laser is rotating, the two counter-propagating waves are slightly shifted in frequency and a beat
interference pattern is observed, which can be used to determine the rotational speed.
Semiconductor ring laser
s have potential applications in all-optical computing. One primary application is as an optical memory device where the direction of propagation represents either 0 or 1. They can maintain the propagation of light in exclusively the clockwise or counterclockwise direction as long as they remain powered.
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
in which the laser cavity has the shape of a ring. Light in ring lasers has two possible directions of propagation: clockwise and counter-clockwise.
Ring lasers are sometimes modified to allow only one direction of propagation by placing a device into the ring which leads to different losses for different propagation directions. For instance, this could be a Faraday rotator
Faraday effect
In physics, the Faraday effect or Faraday rotation is a Magneto-optical phenomenon, that is, an interaction between light and a magnetic field in a medium...
combined with a polarizing element.
One type of ring laser design is a single crystal design, where light reflects around inside the laser crystal so as to circulate in a ring. This is the "monolithic crystal" design, and such devices are known as "non-planar ring oscillators" (NPROs) or MISERs. There are also ring fiber laser
Fiber laser
A fiber laser or fibre laser is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, and thulium. They are related to doped fiber amplifiers, which provide light amplification without lasing...
s.
Ring lasers have several applications. Currently the most widespread application is the ring laser gyroscope
Ring laser gyroscope
A ring laser gyroscope consists of a ring laser having two counter-propagating modes over the same path in order to detect rotation. It operates on the principle of the Sagnac effect which shifts the nulls of the internal standing wave pattern in response to angular rotation...
. If a ring laser is rotating, the two counter-propagating waves are slightly shifted in frequency and a beat
Beat (acoustics)
In acoustics, a beat is an interference between two sounds of slightly different frequencies, perceived as periodic variations in volume whose rate is the difference between the two frequencies....
interference pattern is observed, which can be used to determine the rotational speed.
Semiconductor ring laser
Semiconductor ring laser
Semiconductor ring lasers are miniature ring laser devices with potential applications in optoelectronics, photonics and all-optical circuits. The first SRLs were developed in the 1980s...
s have potential applications in all-optical computing. One primary application is as an optical memory device where the direction of propagation represents either 0 or 1. They can maintain the propagation of light in exclusively the clockwise or counterclockwise direction as long as they remain powered.
See also
- Optical ring resonatorsOptical ring resonatorsAn optical ring resonator is a set of three or more waveguides in which at least one is a closed loop coupled to one input waveguide and one output waveguides...
- Ring laser gyroscopeRing laser gyroscopeA ring laser gyroscope consists of a ring laser having two counter-propagating modes over the same path in order to detect rotation. It operates on the principle of the Sagnac effect which shifts the nulls of the internal standing wave pattern in response to angular rotation...
- Semiconductor ring laserSemiconductor ring laserSemiconductor ring lasers are miniature ring laser devices with potential applications in optoelectronics, photonics and all-optical circuits. The first SRLs were developed in the 1980s...