Masers (Microwave Amplification by Stimulated Emission of Radiation)

1. Masers(Microwave Amplification by Stimulated Emission of Radiation) Ariunaa Bayarbat Chuck Protheroe John Leone Phys 4D 2006SRJC

2. What’s a maser? • Maser is a microwave beam that has been amplified through coherent stimulated radiation emission • What this means is that a molecule is in a certain environment where its outer electrons are in a high energy state and is bombarded by a photon (in this case a microwave) which causes the electrons to ‘jump down’ in energy level and release another photon so that both photons have the same phase, frequency, and direction. This makes the photons add up and create an amplified beam. • Masers occur naturally in space and also are created in laboratories

3. History and background • A maser is based on Einstein’s 1917 stimulated emission principle • Two soviet scientists, Nikolay Basov and Alexander Prokhorov came up with the idea in 1952 • In 1953, the first ammonia maser was developed by Townes, Gordon and Zeiger at Columbia University. • Norman Ramsey created the first laboratory hydrogen maser in 1960. His design is still being used today • Discovery of laser (optical maser) was followed in December of 1958 • Natural masers in space have been discovered since 1965 • Everyone has different names for masers, such as losers

4. Maser Molecule Types • Atomic beam Hydrogen and ammonium • GasRubidium • Solid stateRuby • Dual noble gasHe3 and 129Xe • Liquid Water

5. Maser Beam Types • Originally masers emitted only microwaves • Upon the discovery of emissions of other wavelengths in different parts of the EM spectrum the definition of a maser became hazy • Now masers can be considered as emitting solely microwaves, or any type of stimulated radiation emission depending on the classification used • Basically, despite what you call it, amplification by stimulated emission of radiation can happen for any wavelength in EM spectrum, some are more common then others • Means beam can be x-ray, infra red, radio, visible light(laser), etc.

6. Laboratory vs. Natural • Naturally occurring masers are usually much weaker than laboratory made masers. So radio telescopes are used to detect • The laboratory made masers usually emit more powerful beams because, with technology, we can create the perfect coherence, resonant frequencies, etc. • Natural masers use magnetic field to polarize movement and create coherence

7. Laboratory made Hydrogen Maser • The high frequency and regularity of hydrogen maser can be used as a standard to keep the atomic clock accurate (HMC) • Works similarly to a laser with twomirrors designed to reflectmicrowaves

8. Astrophysical Maser • For an Astrophysical Maser to function in space, it requires a magnetic field for the resonant frequency to be formed • Less effective than engineered masers, because of the inability to make a perfect resonant cavity. • Can be used to identify conditions in space, such as temperature, magnetic field, and velocity. • OH, water, methanol- common types

9. Maser Applications • Improved atomic clock • Electronic amplifiers in radio telescopes • Masers are also used as a low-noise radio frequency amplifiers in satellite communication and radio astronomy • Used as a non-lethal weapon (VMADS) for military purposes

10. Works Cited • http://en.wikipedia.org/wiki/Maser • http://www-ra.phys.utas.edu.au/~sellings/queens.html • http://www.factmonster.com/ce6/sci/A0832083.html • http://www.foundationalquestions.net/townes/articles/lasers.asp • http://www.absoluteastronomy.com/ref/maser • http://www.reference.com/browse/wiki/Maser • http://www.Globalsecurity.org/org/news/2001/010227/zapper.htm • web.haystack.mit.edu/RET/Astrochemistry