Multiple-prism grating laser oscillator
Encyclopedia
Multiple-prism grating laser oscillators, or MPG laser oscillators, use multiple-prism beam expansion
to illuminate a diffraction grating mounted either in Littrow configuration or grazing-incidence configuration. Originally, these narrow-linewidth tunable dispersive oscillators were introduced as multiple-prism Littrow (MPL) grating oscillators, or hybrid multiple-prism near-grazing-incidence (HMPGI) grating cavities
, in organic dye lasers
. However, these designs were quickly adopted for other types of lasers such as gas lasers
, diode lasers, and more recently fiber lasers
.
The multiple-prism dispersion theory
is applied to design these beam expanders either in additive configuration, thus adding or subtracting their dispersion to the dispersion of the grating, or in compensating configuration (yielding zero dispersion at a design wavelength) thus allowing the diffraction grating to control the tuning characteristics of the laser cavity. Optimized solid-state multiple-prism grating laser oscillators have been shown, by Duarte
, to generate pulsed single-longitudinal-mode emission limited only by Heisenberg's uncertainty principle. The laser linewidth
in these experiments is reported as
≈ 350 MHz (or 
≈ 0.0004 nm at 590 nm) in pulses ~ 3 ns wide, at power levels in the kW regime.
Applications of these tunable narrow-linewidth lasers include combustion diagnostics, LIDAR
, laser spectroscopy
, and atomic vapor laser isotope separation.
Beam expander
Beam expanders are used in laser physics either as intracavity or extracavity elements. They can be telescopic in nature or prismatic. Generally prismatic beam expanders use several prisms and are known as multiple-prism beam expanders....
to illuminate a diffraction grating mounted either in Littrow configuration or grazing-incidence configuration. Originally, these narrow-linewidth tunable dispersive oscillators were introduced as multiple-prism Littrow (MPL) grating oscillators, or hybrid multiple-prism near-grazing-incidence (HMPGI) grating cavities
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...
, in organic dye lasers
Dye laser
A dye laser is a laser which uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths. The wide bandwidth makes them particularly suitable for tunable lasers and...
. However, these designs were quickly adopted for other types of lasers such as gas lasers
Gas laser
A gas laser is a laser in which an electric current is discharged through a gas to produce coherent light. The gas laser was the first continuous-light laser and the first laser to operate "on the principle of converting electrical energy to a laser light output...
, diode lasers, and more recently fiber lasers
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...
.
The multiple-prism dispersion theory
Multiple-prism dispersion theory
The first description of multiple-prism arrays, and multiple-prism dispersion, was given by Newton in his book Opticks. Prism pair expanders were introduced by Brewster in 1813. A modern mathematical description of the single-prism dispersion was given by Born and Wolf in 1959...
is applied to design these beam expanders either in additive configuration, thus adding or subtracting their dispersion to the dispersion of the grating, or in compensating configuration (yielding zero dispersion at a design wavelength) thus allowing the diffraction grating to control the tuning characteristics of the laser cavity. Optimized solid-state multiple-prism grating laser oscillators have been shown, by Duarte
F. J. Duarte
F. J. Duarte is a laser physicist and author/editor of several well-known books on tunable lasers. He introduced the generalized multiple-prism dispersion theory and has discovered various multiple-prism grating oscillator laser configurations...
, to generate pulsed single-longitudinal-mode emission limited only by Heisenberg's uncertainty principle. The laser linewidth
Laser linewidth
←Laser linewidth is the spectral linewidth of a laser beam.Two of the most distinctive characteristics of laser emission are spatial coherence and spectral coherence. While spatial coherence is related to the beam divergence of the laser, spectral coherence is evaluated by measuring the laser...
in these experiments is reported as
≈ 350 MHz (or ≈ 0.0004 nm at 590 nm) in pulses ~ 3 ns wide, at power levels in the kW regime.Applications of these tunable narrow-linewidth lasers include combustion diagnostics, LIDAR
LIDAR
LIDAR is an optical remote sensing technology that can measure the distance to, or other properties of a target by illuminating the target with light, often using pulses from a laser...
, laser spectroscopy
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
, and atomic vapor laser isotope separation.
See also
- Dye lasers
- Solid state dye lasersSolid state dye lasersSolid state dye lasers were introduced in 1967 by Soffer and McFarland. In these solid state lasers, the gain medium is a laser dye-doped organic matrix such as poly , rather than a liquid solution of the dye...
- Laser cavityOptical cavityAn 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...
- Laser linewidthLaser linewidth←Laser linewidth is the spectral linewidth of a laser beam.Two of the most distinctive characteristics of laser emission are spatial coherence and spectral coherence. While spatial coherence is related to the beam divergence of the laser, spectral coherence is evaluated by measuring the laser...
- Multiple-prism dispersion theoryMultiple-prism dispersion theoryThe first description of multiple-prism arrays, and multiple-prism dispersion, was given by Newton in his book Opticks. Prism pair expanders were introduced by Brewster in 1813. A modern mathematical description of the single-prism dispersion was given by Born and Wolf in 1959...
- Tunable laserTunable laserA tunable laser is a laser whose wavelength of operation can be altered in a controlled manner. While all laser gain media allow small shifts in output wavelength, only a few types of lasers allow continuous tuning over a significant wavelength range....
s