Fabry-Perot interferometer


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Related to Fabry-Perot interferometer: Brewster's angle

Fabry–Perot interferometer

(fah-bree pair-oh ) A type of interferometer used in spectroscopy to study the fine structure within a spectrum. It has extremely high resolution. It consists essentially of two flat plates, separated and held parallel to each other very accurately. A beam of light, infrared, etc., is multiply reflected in the gap between the inner surfaces, so the plate material must have high reflectivity and low absorption in the wavelength region of interest. The gap is normally precisely controlled and adjustable.

The Fabry–Perot can be thought of as acting like a tunable filter. The gap (d) is related to the wavelength (λ) passed with maximum efficiency by the following equation: 2d cosθ = m λ, where m is an integer known as the order number and θ is the angle of incidence of the beam on the plates (usually arranged to be zero so that cosθ = 1). When the beam is multiply reflected, the particular wavelengths that satisfy the above equation are partially transmitted. This transmitted radiation is focused by a lens or mirror system onto a detector or screen to produce an interference pattern consisting of narrow sharp bright rings on a dark background. The instrument is able to distinguish, or resolve, two very close wavelengths as two almost overlapping superimposed ring patterns, giving it its high resolving power. The wavelength producing the second ring pattern satisfies the equation for the same value of the gap (d) as the first wavelength, but with a different order number (m ). The ring patterns can be separated by the use of a diffraction grating or dispersion by the prism of a spectrograph, which acts as an order sorter. Instruments using two or three Fabry–Perots in series have even higher spectral resolutions.

Fabry-Pérot interferometer

[fä′brē pə′rō ‚int·ə·fə′räm·əd·ər]
(optics)
An interferometer having two parallel glass plates (whose separation of a few centimeters may be varied), silvered on their inner surfaces so that the incoming wave is multiply reflected between them and ultimately transmitted.
References in periodicals archive ?
In order to prepare the mirrors of the Fabry-Perot interferometer, it is known that FBGs, diffraction gratings that only reflect the light of the specific wavelength called Bragg wavelength, are applicable.
Pratt, "Analytical model for low finesse, external cavity, fiber Fabry-Perot interferometers including multiple reflections and angular misalignment," Applied Optics, Vol.
The advantage of the Fabry-Perot interferometer is its very narrow spectral resolution.
One of the major research areas currently under investigation in the project is the field of optical acoustic/seismic/ultrasonic microsensors using the principles of the Fabry-Perot interferometer (FPI) [4, 5], because of the simplicity in the principle and the availability of MEMS technologies for fabrication.
As with the Fabry-Perot interferometer, the resonant frequency and cavity Q are measured with and without the test sample in the cavity.
A micromachined Fabry-Perot interferometer developed by IC Sensors in conjunction with British Telecom (London) is precision-assembled from two separate pieces of silicon.
The Fabry-Perot interferometer was invented around the turn of the century by two French physicists, and it was applied to the Orion Nebula as early as 1914.
Successfully awarded as a result of HBM and Smartecs joint experience and ability to supply FBG (Fiber Bragg Grating) technology and Fabry-Perot interferometers to measure strain, displacement and temperature in the cryogenic environment found in the ITER magnets, the tender is one of the largest single orders ever received at FiberSensing.
Recently, several types of optical waveguide sensors or optical fiber-based refractometer have been proposed, including long period fiber gratings, Fabry-Perot interferometers, and Mach-Zehnder interferometers (MZI).