Masers

Hess H F, Kochanski G P, Doyle J M, Greytak T J, and Kleppner D 1986 Spin-polarized hydrogen maser Phys.Rev. A 34 1602-4... 

Gadolinium ethyl sulfate has extremely low noise characteristics and may find use in duplicating the performance of amplifiers, such as the maser. 

The word laser is an acronym derived from light amplification by the stimulated emission of radiation . If the light concerned is in the microwave region then the alternative acronym maser is often used. Although the first such device to be constructed was the ammonia maser in 1954 it is the lasers made subsequently which operate in the infrared, visible or ultraviolet regions of the spectrum which have made a greater impact. 

Mar tius Yellow Maruzen process Mascaras Masers Mashing... 

Synthetic gemstone materials often have multiple uses. Synthetic mby and colodess sapphire are used for watch bearings, unscratchable watch crystals, and bar-code reader windows. Synthetic quartz oscillators are used for precision time-keeping, citizen s band radio (CB) crystals, and filters. Synthetic mby, emerald, and garnets are used for masers and lasers (qv). 

C. H. Townes (Massachusetts Institute of Technology), and N. G. Basov and A. M. Prokhorov (Moscow) fundamental work in the field of quantum electronics, which led to the construction of oscillators and amplifiers based on the maser-laser-principle. 

N. F. Ramsey (Harvard) invention of the separated oscillatory fields method and its use in the hydrogen maser and other atomic clocks. 

Maser, /. speckle, spot, mark grain (of wood) pi.) measles. 

By 1954 Townes, with the help of graduate students Herbert Zeiger and James Gordon, developed the maser, an acronym for microwave amplification by stimulated emission of radiation. The maser had... 

In 1957, this team of brothers-in-law started working together on Townes s idea for an optical maser. They found atoms that they felt had the most potential, based on transitional probabilities and lifetimes. However, there was still one major problem In the visible light portion of the electromagnetic spectrum, atoms don t remain in an excited state as long as... 

Townes s academic life continued. He served as provost of MIT from 1961 to 1966. In 1964, Townes received the Nobel Prize in physics for work in quantum electronics leading to construction of oscillators and amplifiers based on the maser-laser principle. He was named university professor at the University of California-Berkeley in 1967. There he worked for more than 20 years in astrophysics. Ironically, this field is one of many that were transformed by die laser, and Townes often tised lasers in his subsequent research. 

Peny, T. S. (1991). Charles H. Townes Masers, Lasers More. TEEE Spectrwn 28 32. 

Maser, F., Bode,K., Pillai, V. N. R. and Mutter, M. Conformational Studies on Model Peptides. Their Contribution to Synthetic, Structural and Functional Innovations on Proteins. Vol. 65, pp. 177 — 214. 

The shape of the maser curve not only depends on the rubber compound, but also on the surface on which it slides. On dry, clean polished glass the friction master curve for gum rubbers rises from very small values at low log ajv to a maximum which may reach friction coefficients of more than 3 and falls at high log ajv to values which are normally associated with hard materials, i.e., 0.3 shown for an ABR gum compound in Figure 26.2. If the position of the maximum on the log a-fV axis for different gum rubbers is compared with that of their maximum log E frequency curves, a constant length A = 6 X 10 m results which is of molecular dimension, indicating that this is an adhesion process [10]. 

Mobus E, M Jahn, R Schmid, D Jahn, E Maser (1997) Testosterone-regulated expression of enzymes involved in steroid and aromatic hydrocarbon catabolism in Comamonas testosteroni. J Bacteriol 179 5951-5955. 

Hie possibility that a particle with energy Jess than the barrier height can penetrate is a quantum-mechanical phenomenon known as the tunnel effect. A number of examples are known in physics and chemistry. The problem illustrated here with a rectangular barrier was used by Eyring to estimate the rates of chemical reactions. ft forms the basis of what is known as the absolute reaction-rate theory. Another, more recent example is the inversion of the ammonia molecule, which was exploited in the ammonia maser - the fbiemnner of the laser (see Section 9.4,1). 

The presence of the potential barrier in the ammonia molecule results in splitting of the vibrational energy levels, as shown in Fig. 5. The separation between die two components of the first level is equal to 23.87 GHz 0.79 cm-1). The corresponding absorption line is easily observable in the microwave spectrum of ammonia. In fact, this transition was utilized in the MASER,f the forerunner of die LASER. 

First, let s look at what current lasers and masers do. Lasers vary in size from single atoms, or submicroscopic size, to lasers as big as tall buildings. Well, the single atoms in small lasers produce fantastically small amounts of power - let s say, 10 16 watts. The big ones have produced as much as 10+16 watts - that is, ten million billion watts, more than we have from any other kind of source. Now, that lasts for a short time, because it would be too expensive to have it on all the time, of course. Nevertheless, it s very powerful, and that great power produces an intensity which allows us to study and to understand new states of matter with very high energy concentration. 

Also, the laser or maser measures time very precisely. The hydrogen maser, for example, can measure times with a precision of about 10 15. It can also measure short times - as short as 10 15 seconds. So we can see atomic and molecular phenomena occurring on very short time scales. 

Amplifiers. The maser produced a new kind of amplifier, which was about a hundred times more sensitive than the amplifiers we had at the time. The maser had a so-called noise temperature of about one degree Absolute - you can get down to about that amount of noise. However, other amplifiers at that time were a hundred times more noisy. Thus the maser allowed us to measure more sensitively. 

Well, those are some of the kinds of things that masers and lasers have made possible. 

The maser and the laser, I m delighted to say, have been very useful scientific tools. And that was my primary interest, to get a good scientific tool to do new things. Since the Nobel Prize in 1954 there have been twelve other Nobel Prizes that used masers or lasers as tools. That doesn t mean that the masers and lasers produced the Nobel Prize, but the person who did the Nobel Prize work was able to do things that he couldn t do otherwise, using masers and lasers as tools. 

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