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Encyclopedia > Maser
A hydrogen radio frequency discharge, the first element inside a hydrogen maser (see description below)

A maser is a device that produces coherent electromagnetic waves through amplification due to stimulated emission. Historically the term came from the acronym "Microwave Amplification by Stimulated Emission of Radiation", although modern masers emit over a broad portion of the electromagnetic spectrum. This has led some to replace "microwave" with "molecular" in the acronym, as suggested by Townes.[1] When optical coherent oscillators were first developed, they were called optical masers, but it has become more common to refer to these as lasers. See the section on terminology below for more on this. Image File history File links Download high resolution version (530x694, 205 KB)Retrieved at http://horology. ... Image File history File links Download high resolution version (530x694, 205 KB)Retrieved at http://horology. ... A hydrogen radio frequency discharge, the first element inside a hydrogen maser (see description below) A maser is a device that produces coherent electromagnetic waves through amplification due to stimulated emission. ... Coherence is the property of wave-like states that enables them to exhibit interference. ... Electromagnetic radiation or EM radiation is a combination (cross product) of oscillating electric and magnetic fields perpendicular to each other, moving through space as a wave, effectively transporting energy and momentum. ... In optics, stimulated emission is the process by which, when perturbed by a photon, matter may lose energy resulting in the creation of another photon. ... Charles Hard Townes (born July 28, American physicist and educator. ... Experiment with a laser (US Military) In physics, a laser is a device that emits light through a specific mechanism for which the term laser is an acronym: Light Amplification by Stimulated Emission of Radiation. ...

Contents

History

Theoretically, reflecting principles previously discussed by Joseph Weber at the June 1952 conference of the Institute of Radio Engineers,[2] the principle of the maser was described by Nikolay Basov and Alexander Prokhorov from Lebedev Institute of Physics at an All-Union Conference on Radio-Spectroscopy held by USSR Academy of Sciences in May 1952. They subsequently published their results in October 1954. Independently, Charles H. Townes, J. P. Gordon, and H. J. Zeiger built the first maser at Columbia University in 1953. The device used stimulated emission in a stream of energized ammonia molecules to produce amplification of microwaves at a frequency of 24 gigahertz. Townes later worked with Arthur L. Schawlow to describe the principle of the optical maser, or laser, which Theodore H. Maiman first demonstrated in 1960. For their research in this field Townes, Basov and Prokhorov were awarded the Nobel Prize in Physics in 1964. Joseph Weber (May 17, 1919 – September 30, 2000) was an American physicist. ... Following several attempts to form a technical organization of wireless practitioners in 1908-1912, the Institute of Radio Engineers (IRE) was finally established in 1912 in New York. ... Nikolay Gennadiyevich Basov (Russian:Николай Геннадиевич Басов) (December 14, 1922 – July 1, 2001) was a Soviet/Russian physicist and educator. ... Aleksandr Mikhailovich Prokhorov (Russian: Александр Михайлович Прохоров) (July 11, 1916 – January 8, 2002) was an Australian-Russian physicist. ... The Lebedev Physical Institute of the Russian Academy of Sciences is a Russian research institute specializing in physics. ... Russian Academy of Sciences (Росси́йская Акаде́мия Нау́к) is the national academy of Russia. ... 1952 (MCMLII) was a Leap year starting on Tuesday (link will take you to calendar). ... Year 1954 (MCMLIV) was a common year (link will display full calendar) of the Gregorian calendar. ... Charles Hard Townes (born July 28, American physicist and educator. ... Columbia University is a private research university in the United States. ... Year 1953 (MCMLIII) was a common year starting on Thursday (link will display full calendar) of the Gregorian calendar. ... In optics, stimulated emission is the process by which, when perturbed by a photon, matter may lose energy resulting in the creation of another photon. ... Ammonia is a compound with the formula NH3. ... Microwaves are electromagnetic waves with wavelengths longer than those of terahertz (THz) frequencies, but relatively short for radio waves. ... A gigahertz is a billion hertz or a thousand megahertz, a measure of frequency. ... Arthur Leonard Schawlow (May 5, 1921–April 28, 1999) was an American physicist. ... Theodore Harold Maiman (born July 11, 1927) is an American physicist who invented the first operable laser device (patent number 3,353,115). ... Year 1960 (MCMLX) was a leap year starting on Friday (link will display full calendar) of the Gregorian calendar. ... Hannes Alfvén (1908–1995) accepting the Nobel Prize for his work on magnetohydrodynamics [1]. List of Nobel Prize laureates in Physics from 1901 to the present day. ... 1964 (MCMLXIV) was a leap year starting on Wednesday (the link is to a full 1964 calendar). ...


Technology

The maser is based on the principle of stimulated emission proposed by Albert Einstein in 1917. When atoms have been put into an excited energy state, they can amplify radiation at the proper frequency. By putting such an amplifying medium in a resonant cavity, feedback is created that can produce coherent radiation. In optics, stimulated emission is the process by which, when perturbed by a photon, matter may lose energy resulting in the creation of another photon. ... “Einstein” redirects here. ... A cavity resonator uses resonance to amplify a wave. ... Coherence is the property of wave-like states that enables them to exhibit interference. ...


Some common types of masers

  • Atomic beam masers
    • Ammonia maser
    • Hydrogen maser
  • Gas masers
    • Rubidium maser
  • Solid State masers
    • Ruby maser

The dual noble gas maser is an example of a masing medium which is nonpolar.[3] Neon, like all noble gases, has a full valence (outermost) electron shell. ... In chemistry, a nonpolar compound is one that does not have concentrations of positive or negative electric charge. ...


Uses

Masers serve as high precision frequency references. These "atomic frequency standards" are one form of atomic clock. They are also used as electronic amplifiers in radio telescopes. FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. ... Chip-scale atomic clock unveiled by NIST An Atomic Clock is a type of clock that uses an atomic resonance frequency standard to feed its counter. ... It has been suggested that Rf power amplifier be merged into this article or section. ... The 64 meter radio telescope at Parkes Observatory A radio telescope is a form of directional radio antenna most often used in radio astronomy and in tracking and collecting data from satellites and space probes (see Deep Space Network), and are also used in the SETI project. ...


Hydrogen maser

A hydrogen maser.

Today, the most important type of maser is the hydrogen maser which is currently used as an atomic frequency standard. Together with other types of atomic clocks, they constitute the "Temps Atomique International" or TAI. This is the international time scale, which is coordinated by the Bureau International des Poids et Mesures, or BIPM. Image File history File links Hmaser. ... Image File history File links Hmaser. ... Chip-scale atomic clock unveiled by NIST An Atomic Clock is a type of clock that uses an atomic resonance frequency standard to feed its counter. ... International Atomic Time (TAI, from the French name Temps Atomique International) is a high-precision atomic time standard that tracks proper time on Earths geoid. ... The International Bureau of Weights and Measures is the English name of the Bureau international des poids et mesures (BIPM, often written in English Bureau International des Poids et Mesures), a standards organisation, one of the three organizations established to maintain the International System of Units (SI) under the terms...


It was Norman Ramsey and his colleagues who first realized this device. Today's masers are identical to the original design. The maser oscillation relies on stimulated emission between two hyperfine levels of atomic hydrogen. Here is a brief description of how it works: Norman Foster Ramsey, Jr. ... In atomic physics, hyperfine structure is a small perturbation in the energy levels (or spectra) of atoms or molecules due to the magnetic dipole-dipole interaction, arising from the interaction of the nuclear magnetic dipole with the magnetic field of the electron. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ...

  • First, a beam of atomic hydrogen is produced. This is done by submitting the gas at low pressure to an RF discharge (see the picture on this page).
  • The next step is "state selection"—in order to get some stimulated emission, it is necessary to create a population inversion of the atoms. This is done in a way that is very similar to the famous Stern-Gerlach experiment. After passing through an aperture and a magnetic field, many of the atoms in the beam are left in the upper energy level of the lasing transition. From this state, the atoms can decay to the lower state and emit some microwave radiation.
  • A small fraction of the signal in the microwave cavity is coupled into a coaxial cable and then sent to a coherent receiver.
  • The microwave signal coming out of the maser is very weak (a few pW) and the frequency is extremely stable but can not be changed. The coherent receiver is used to amplify the signal and change the frequency. This is done using a series of phase-locked loops and a high performance quartz oscillator.

In physics, specifically statistical mechanics, the concept of population inversion is of fundamental importance in laser science because the production of a population inversion is a necessary step in the workings of a laser. ... In quantum mechanics, the Stern–Gerlach experiment, named after Otto Stern and Walther Gerlach, is a celebrated experiment in 1920 on deflection of particles, often used to illustrate basic principles of quantum mechanics. ... The Q factor or quality factor is a measure of the quality of a resonant system. ... Generally, an amplifier is any device that uses a small amount of energy to control a larger amount of energy. ... It has been suggested that this article or section be merged with Feedback loop. ... Oscillation is the variation, typically in time, of some measure as seen, for example, in a swinging pendulum. ... This article is about resonance in physics. ... In atomic physics, hyperfine structure is a small perturbation in the energy levels (or spectra) of atoms or molecules due to the magnetic dipole-dipole interaction, arising from the interaction of the nuclear magnetic dipole with the magnetic field of the electron. ... In electronics, a phase-locked loop (PLL) is a closed-loop feedback control system that generates and outputs a signal in relation to the frequency and phase of an input (reference) signal. ... A crystal oscillator is an electronic device that uses the mechanical resonance of a physical crystal of piezoelectric material to create an electrical signal with a very precise frequency. ...

Astrophysical masers

Main article: Astrophysical maser

Stimulated microwave and radio wave emission is observed in astronomy, and this is usually called "masing", even in the absence of the resonant feedback that would be required for a true maser. Technically this form of stimulated emission is called superradiant emission, and it is closely associated with lasing and masing. Such emission is observed from molecules such as water (H2O), hydroxyl radicals (OH), methanol (CH3OH), formaldehyde (CH2O), and silicon monoxide (SiO). An astrophysical maser is a naturally occurring source of stimulated spectral line emission, typically in the microwave portion of the electromagnetic spectrum. ... A giant Hubble mosaic of the Crab Nebula, a supernova remnant Astronomy (also frequently referred to as astrophysics) is the scientific study of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earths atmosphere (such as the cosmic background radiation). ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... In chemistry, radicals (often referred to as free radicals) are atomic or molecular species with unpaired electrons on an otherwise open shell configuration. ... Natural Occurance Astronomical OH masers were the first masers to be discovered in space and have been observed in more environments than any other type of maser. ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol (ethyl alcohol). ... The chemical compound formaldehyde (also known as methanal) is a gas with a pungent smell. ...


Maser-like stimulated emission also occurs in nature in interstellar space. Water molecules in star-forming regions can undergo a population inversion and emit radiation at 22 GHz, creating the brightest spectral line in the radio universe. Some water masers also emit radiation from a vibrational mode at 96 GHz. The interstellar medium (or ISM) is a term used in astronomy to describe the rarefied gas and dust that exists between the stars (or their immediate circumstellar environment) within a galaxy. ... Space has been an interest for philosophers and scientists for much of human history. ... STAR is an acronym for: Organizations Society of Ticket Agents and Retailers], the self-regulatory body for the entertainment ticket industry in the UK. Society for Telescopy, Astronomy, and Radio, a non-profit New Jersey astronomy club. ... In physics, specifically statistical mechanics, the concept of population inversion is of fundamental importance in laser science because the production of a population inversion is a necessary step in the workings of a laser. ... Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... A quantum vibration is a vibration of a chemical bond in a molecule that must be treated quantum mechanically. ...


Terminology

The meaning of the term maser has changed slightly since its introduction. Initially the acronym was universally given as "microwave amplification by stimulated emission of radiation," which described devices which emitted in the microwave region of the electromagnetic spectrum. The principle of stimulated emission has since been extended to more devices and frequencies, and so the original acronym is sometimes modified, as suggested by Charles H. Townes,[4] to "molecular amplification by stimulated emission of radiation." Some have asserted that Townes's efforts to extend the acronym in this way were primarily motivated by the desire to increase the importance of his invention, and his reputation in the scientific community.[5] Microwaves are electromagnetic waves with wavelengths longer than those of terahertz (THz) frequencies, but relatively short for radio waves. ... Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... In optics, stimulated emission is the process by which, when perturbed by a photon, matter may lose energy resulting in the creation of another photon. ... Charles Hard Townes (born July 28, American physicist and educator. ...


When the laser was developed, Townes and Schawlow and their colleagues at Bell Labs pushed the use of the term optical maser, but this was largely abandoned in favor of laser, coined by their rival Gordon Gould.[6] In modern usage, devices that emit in the X-ray through infrared portions of the spectrum are typically called lasers, and devices that emit in the microwave region and below are commonly called masers, regardless of whether they emit microwaves or other frequencies. Arthur Leonard Schawlow (May 5, 1921–April 28, 1999) was an American physicist. ... Gordon Gould (July 17, 1920 — September 16, 2005) was an American physicist and the credited inventor of the laser. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... Image of two girls in mid-infrared (thermal) light (false-color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... Experiment with a laser (US Military) In physics, a laser is a device that emits light through a specific mechanism for which the term laser is an acronym: Light Amplification by Stimulated Emission of Radiation. ...


Gould originally proposed distinct names for devices that emit in each portion of the spectrum, including grasers (gamma ray lasers), xasers (x-ray lasers), uvasers (ultraviolet lasers), lasers (visible lasers), irasers (infrared lasers), masers (microwave masers), and rasers (RF masers). Most of these terms never caught on, however, and all have now become (apart from in science fiction) obsolete except for maser and laser. This article is about electromagnetic radiation. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... “UV” redirects here. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... Image of two girls in mid-infrared (thermal) light (false-color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... Microwaves are electromagnetic waves with wavelengths longer than those of terahertz (THz) frequencies, but relatively short for radio waves. ... It has been suggested that this article or section be merged with Radio waves. ...


Masers in science fiction

Masers often appear as weapons in science fiction movies and novels. Their characteristics often differ from those of real masers, however, and it is doubtful whether a practical maser weapon such as these can actually be made. Science fiction is a form of speculative fiction principally dealing with the impact of imagined science and technology, or both, upon society and persons as individuals. ...


Some notable science fiction appearances of masers:

  • Masers are the most recognizable weapon in the Godzilla series and Toho's other monster movies. "Maser tanks" are often deployed against monsters. These fire a bolt of electricity, presumably created by amplified microwaves. Maser tanks have also appeared in various video games and in other science fiction movies.
  • Masers are common in anime and Japanese-inspired animated science fiction stories. They have appeared in the Transformers, Gundam SEED, GaoGaiGar, Code Geass and others. In Gundam SEED, masers are described as sound waves focused in laser-like fashion, rather than microwave devices.
  • Masers are used predominantly as weaponry, both from spaceships and by ground troops in Peter F. Hamilton's Night's Dawn universe, as well as appearing in his Commonwealth saga.
  • Masers are frequently used as the assault weapon-of-choice by military forces in William Shatner's fictional novel series "Quest for Tomorrow".
  • In the Star Wars Expanded Universe, masers are the primary weapon for the Chiss race, on their fighters and for handheld rifles.
  • The DANGI Maser is a prominent and very lethal weapon in a popular (and free) scenario for Marathon called Marathon Rubicon.
  • In Carl Sagan's novel Contact, the main character, Ellie Arroway, does her thesis project on developing a "ruby maser".
  • In the video game Ratchet and Clank: Size Matters, there is a weapon called the Laser Tracer. When fully upgraded to level 4, it becomes the Optical Maser Array.
  • In the Star Control series history, the Androsynth defeated the humans' defenses with the use of MASER technology.
  • The Monkeylord unit in Supreme Commander is armed with a "Microwave Laser".

For other uses, see Godzilla (disambiguation). ... The English-language version of Tohos famous logo, used from the early 1960s to the late 1990s. ... Namcos Pac-Man was a hit, and became a universal phenomenon. ... The main cast of the anime Cowboy Bebop (1998) (L to R: Spike Spiegel, Jet Black, Ed Tivrusky, Faye Valentine, and Ein the dog) For the oleo-resin, see Animé (oleo-resin). ... This page is about the original Transformers animated series. ... Title of the series Mobile Suit Gundam SEED (or Gundam Seed) is an anime television series from Japan. ... The King of Braves GaoGaiGar (勇者王ガオガイガー or Yuusha-Oh GaoGaiGar) is a Japanese animated television series series made in 1997, and the eighth and final Yuusha or Brave Fighter series funded by Takara and produced by Sunrise during the lapse in Transformers popularity. ... Code Geass: Lelouch of the Rebellion ) is a Japanese anime television series, created by Sunrise. ... Experiment with a laser (US Military) In physics, a laser is a device that emits light through a specific mechanism for which the term laser is an acronym: Light Amplification by Stimulated Emission of Radiation. ... Peter F. Hamilton Peter F. Hamilton Peter F. Hamilton (born 1960, Rutland, England), is a British science fiction author. ... British author Peter F. Hamiltons The Nights Dawn Trilogy consists of three epic science fiction novels: The Reality Dysfunction (1996), The Neutronium Alchemist (1997), and The Naked God (1999). ... Star Wars is an epic science fantasy saga and fictional universe created by George Lucas during the late 1970s. ... This article does not cite any references or sources. ... In the fictional Star Wars universe, the Chiss are a humanoid species with pale blue skin, blue-black hair and glowing red eyes. ... The Marathon Trilogy is a science fiction series of first-person shooter computer games from Bungie Software, originally released for the Macintosh. ... Look up Contact in Wiktionary, the free dictionary. ... The Star Control series is a trilogy of computer games with a cult following. ... The Androsynth are a fictional race of beings featured in the Star Control science fiction computer game series. ... Supreme Commander - Wikipedia, the free encyclopedia /**/ @import /skins-1. ...

See also

Experiment with a laser (US Military) In physics, a laser is a device that emits light through a specific mechanism for which the term laser is an acronym: Light Amplification by Stimulated Emission of Radiation. ... An immense slab of continuous melt processed neodymium doped laser glass for use on the National Ignition Facility. ...

Footnotes

  1. ^ http://nobelprize.org/physics/laureates/1964/townes-lecture.pdf
  2. ^ Yodh, Gaurang B. and Wallis, Richard F. (2001). "Obituaries: Joseph Weber". Physics Today 54 (7). 
  3. ^ http://cfa-www.harvard.edu/Walsworth/Activities/DNGM/old-DNGM.html
  4. ^ http://nobelprize.org/physics/laureates/1964/townes-lecture.pdf
  5. ^ Taylor, Nick (2000). LASER: The inventor, the Nobel laureate, and the thirty-year patent war. New York: Simon & Schuster. ISBN 0-684-83515-0. 
  6. ^ Taylor (2000), p. 66–70.

References

  • J.R. Singer, Masers, John Whiley and Sons Inc., 1959.
  • J. Vanier, C. Audoin, The Quantum Physics of Atomic Frequency Standards, Adam Hilger, Bristol, 1989.
  • Cartoon Megas XLR 2005

Megas XLR is an American animated television series that aired on the Toonami block on Cartoon Network and is produced by Cartoon Network Studios. ...

External links

  • arXiv.org search for "maser"
  • Noble gas Maser
  • The Red Shift (Hydrogen Maser Clock) Experiment

  Results from FactBites:
 
Maser - Wikipedia, the free encyclopedia (1230 words)
The maser is based on the principle of stimulated emission proposed by Albert Einstein in 1917.
The dual noble gas maser [2] is an example of a masing medium which is nonpolar.
Masers are used predominantly as weaponry, both from spaceships and by ground troops in Peter F. Hamilton's Night's Dawn universe, as well as appearing in his Commonwealth saga.
Astrophysical maser - Wikipedia, the free encyclopedia (2339 words)
In 1997, 1667-MHz maser emission from the OH molecule was observed from comet Hale-Bopp.
The 1720 MHz maser transition of the OH molecule is known to be associated with supernova remnants that interact with molecular clouds.
Astronomical masers remain an active field of research in radio astronomy and laboratory astrophysics due, in part, to the fact that they are valuable diagnostic tools for astrophysical environments which may otherwise elude rigorous quantitative study and because they may facilitate the study of conditions which are inaccessible in terrestrial laboratories.
  More results at FactBites »

 
 

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