| • Science | • People | • Locations | • Timeline |
This technique is the basis for radio telescope arrays which, spread out over a wide area of hundreds of miles, can together produce a picture with resolution similar or equivalent to a single telescope with the diameter of the combined spread of telescopes. It has more recently been used for arrays of optical telescopes such as the Cambridge Optical Aperture Synthesis Telescope (COAST), resulting in the highest resolution optical images ever achieved in astronomy. The proposed Keck interferometer will have 6 optical telescopes working in such an array for astronomy research, while the Magdalena Ridge Observatory Interferometer may have an array of up to 10 optical telescopes.
An interferometer works on the principle that two waves that coincide with the same phase will amplify each other while two waves that have opposite phases will cancel each other out.
The basic building blocks of a laboratory Michelson interferometer are a monochromatic light source, usually a laser, a detector, two mirrors and one semitransparent mirror. These are put together as shown in the figure.
There are two paths from the light source to the detector. One reflects off the semi-transparent mirror, goes to the top mirror and then reflectsThe term reflection (also spelt reflexion can refer to several different concepts: In mathematics, reflection is the transformation of a space. In physics, reflection is a wave phenomenon. In computer science, reflection is a programming language feature back, goes through the semi-transparent mirror, to the detector. The other first goes through the semi-transparent mirror, to the mirror on the right, reflects back to the semi-transparent mirror, then reflects from the semi-transparent mirror into the detector.
If these two paths differ by a whole number (including 0) of wavelengthThe wavelength is the distance between repeating units of a wave pattern. It is commonly designated by the greek letter lambda (λ). In a sine wave, the wavelength is the distance between peaks: The x axis represents distance, and I would be some vas, there is constructive interferenceIn communications, interference is anything which alters, modifies, or disrupts a message; as it travels along a channel, between a source and a receiver. Below is an article about the physical phenomenon of wave interference. See also the legal concept o and a strong signal at the detector. If they differ by a whole number and a half wavelengths (eg, 0.5, 1.5, 2.5 ...) there is destructive interference and a weak signal.
The interferometer setup shown to the right was used in the famous Michelson-Morley experimentThe Michelson-Morley experiment one of the most important and famous experiments in the history of physics, was performed in 1887 (at what is now Case Western Reserve University), and is considered to be the first strong evidence against the theory of a l that provided evidence for special relativitySpecial relativity (SR or the special theory of relativity is the physical theory published in 1905 by Albert Einstein. It replaced Newtonian notions of space and time, and incorporated electromagnetism as represented by Maxwell's equations. The theory is. Of course, in MichelsonAlbert Abraham Michelson ( December 19, 1852 May 9, 1931), was a Polish- American physicist known for his work on the measurement of the speed of light. In 1907 he received a Nobel prize for physics. Life Michelson was born in Strzelno, Poland (then Strel's day, they did not have lasers, so instead they used a gas discharge lamp, a filter, and a thin slot or pinhole to make more-or-less coherentCoherence is a property of waves that measures the ability of the waves to interfere with each other. Two waves that are coherent can be combined to produce an unmoving distribution of constructive and destructive interference (a visible interference patt monochromatic light. In one version of the Michelson- Morley experiment, they even ran the interferometer off starlight. The Michelson interferometer finds use not only in these experiments but also for other purposes, e.g. in gravitational wave detection.
There are many other types of interferometer. They all work on the same basic principles, but the geometry is different for the different types. One familar use of the technique is in radio and optical interferometer telescope s. However, interferometers are perhaps even more widely used in integrated optical circuits , in the form of a Mach-Zehnder interferometer, in which light interferes between two branches of a waveguide that are (typically) externally modulated to vary their relative phase. Such components are the basis of a wide variety of devices, from RF modulators to sensors to optical switches.
The highest-resolution astronomical images are produced using interferometers (at both optical and radio wavelengths). Here is a description of astronomical interferometry.
Another geometry is the Sagnac interferometer.