An interferometer is a measuring device whose operation is based on the phenomenon of interference . The principle of operation of the interferometer is as follows: a beam of electromagnetic radiation (light, radio waves, etc.) with the help of one device or another is spatially divided into two or more coherent beams. Each of the beams passes through various optical paths and is sent to the screen, creating an interference pattern by which it is possible to establish the phase difference of the interfering beams at a given point in the picture.
Interferometers are used both for accurate measurement of lengths, in particular in machine and machine building , and for assessing the quality of optical surfaces and checking optical systems as a whole.
Content
Glass flat plates
For accurate measurements of flatness and parallelism of surfaces of various parts, flat glass plates are used. They are made in the form of cylinders about ten centimeters in size with polished bases, which serve as measurements by the interference method [1] . When measuring the flatness of the surface, it is applied to one of the bases of a flat glass plate, which is illuminated with monochromatic light through the second base. If the measured surface is sufficiently flat, even parallel interference fringes are formed on the illuminated surface of the flat glass plate. In the case of deviations from flatness, the stripes are obtained to varying degrees curved. Flat glass plates are also used to measure and control length standards - end measures . The parameters of flat glass plates are determined by GOST 2923–75, examples of their models: PI-60, PI-80, PI-100, PI-120.
Interferometers in Astronomy
Interferometers are widely used in astronomy to create high-resolution radio and optical telescopes . They allow you to replace a telescope with a large aperture (which is necessary to obtain a high resolution ) with a lattice of telescopes with smaller apertures connected by the principle of an interferometer. Interferometers are particularly successful in radio astronomy . Due to the fact that not so strict requirements are imposed on relatively low frequencies for sampling and digitizing signals, it is possible to integrate radio telescopes into VLBI networks.
Experiments for observing interference
- Jung's Experience
- Lloyd's Mirror
- Fresnel Mirrors
- Fresnel Biprism
- Thin Film Interference
- Newton's rings
Types of Interferometers
- Jamena Interferometer
- Mach Interferometer - Zehnder
- Rozhdestvensky Interferometer
- Mine interferometer
- Michelson Interferometer
- Heterodyne interferometer
- Interferometer unequal
- Kösters Interferometer
- Twyman-Green Interferometer
- Chapsky Interferometer
- Linnik Interferometer
- Michelson's Star Interferometer
- Rayleigh Interferometer
- Sagnac Interferometer
- Fizeau Interferometer
- Resonator Fabry - Perot (originally - interferometer Fabry - Perot )
- Shear interferometer
Non-Classical Interferometers
In the 1950s and 1960s, astronomers R. Brown and R. Twiss developed an optical intensity interferometer in which only radiation intensities are measured.
See also
- Light interference
- Radio interferometer
- Holography
- Prism (optics)
- Atacama Large Millimeter Array
- Shuttle Radar Topography Mission
Notes
- ↑ Flat glass plates // Big Soviet Encyclopedia , 2nd ed. B. A. Vvedensky. - The Great Soviet Encyclopedia, 1955. - T. 33 . - S. 195 .
Links
- About interferometry in astronomy
- Theory of Holographic Interferometry
- More on the principle of operation of the radio interferometer
- Examples of practical application of interferometry
- Optical interferometry in astronomy reaches a new frontier
- Kolomiytsov Yu. V. Interferometers. Fundamentals of engineering theory, application. 1976
- Gravity testing using atomic interferometry . Date of appeal September 14, 2013. (unavailable link) (English)