Maser microwave amplification by stimulated emission

Since htjkT is small, the ratio of the two transition probabilities is small and Amn Bmn p (vam). This condition is obtained in the microwave region and is utilized in the construction of masers (microwave amplification by stimulated emission of radiation). 

Microwaves sources include electron beams (e.g.. magnetron, klystron), semiconductors (e.g, Gunn diode, transistor) and masers (microwave amplification by stimulated emission of radiation) [88]. The depth of penetration d of microwaves into a dielectric is a function of the lo.ss factor S in the dielectric material and the frequency / of operation (or vacuum wavelength aq) [89] and is given by... 

The idea of amplification of EM radiation by stimulated emission was first realized for microwaves. The MASER (microwave amplification by stimulated emission of radiation) was developed in the Soviet Union in the early part of the 1950s, particularly by N. Basov and A. Prokhorov. At the same time, it was developed by C. H. Townes, A. L. Schawlow, and others in the United States. Originally, the laser was called light-maser, but the name was changed to LASER (light amplification by stimulated emission of radiation). 

Maser (Charles Hard Townes) The maser (microwave amplification by stimulated emission of radiation) is a laser for microwaves. Discovered later, the laser patterned its name the acronym maser. ... 

Lymph A clear, colorless fluid which circulates through the vessels of the lymphatic system. Maser Microwave amplification by stimulated emission of radiation. 

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... 

The term MASER stands for Microwave Amplification by Stimulated Emission Radiation... 

Atomic filter A sort of device with an ultra-high Q obtained by using the vibrations of atoms. These systems employ the microwave amplification by stimulated emission of radiation (maser) of substances such as cesium or ruby to stabilize the primary oscillator of extremely precise devices that work at high frequency values [i]. 

Charles Townes was the first person to take advantage of the stimulated emission process to be used in the form of an amplifier by conceiving and constructing the first maser (an acronym for microwave amplification by stimulated emission of radiation). The maser produced a pure beam of microwaves that were anticipated to be useful for communications in a similar way to that of a klystron or a traveling-wave tube. The first maser was produced in ammonia vapor, and the inversion occurred between... 

The acronym MASER denotes Microwave Amplification by Stimulated Emission of Radiation." However, observations have shown that masers emit over a broad portion of the electromagnetic spectrum so the word microwave does no longer mean that such phenomena can only be observed in the microwave range. 

Amplification by Stimulated Emission of Radiation . (Similar devices producing coherent beams of microwave radiation are known as masers) A typical arrangement for a pulsed ruby laser is depicted in Figure 8.5. 

A laser (acronym for light amplification by stimulated emission of radiation) amplifies light in a different region of the electromagnetic spectrum by the same method that the maser amplifies microwaves. 

During recent years, the techniques of spectroscopy have been greatly enhanced by the introduction of lasers. The word laser is an acronym for Light Amplification by Stimulated Emission of Radiation. The development of this field began in 1953 with the introduction by the American physicist Charles H. Townes of the maser, which stands for Microwave Amjplification by Stimulated Emission of Radiation. 

In 1951, Charles H. Townes had an idea for stimulated emission of microwave radiation. He and his coworkers at Columbia University used a transition of the ammonia molecule that occurred in the microwave region of its spectrum in order to create a maser (micro-wave amplification by stimulated emission of radiation). On producing ammonia molecules in the upper state involved in the transition, the application of microwave radiation at the transition frequency caused excited state molecules to emit a photon and drop to the ground state. Since the emitted photons were at the same frequency as that of the incident radiation, the process led to an amplification of the applied radiation. 

This illustrates why resonant cavities for amplification by stimulated emission in the visible region (lasers) need to have very much greater 0 values than those for the amplification of microwaves (masers). 

The first stimulated-emission amplification device was produced at microwave frequencies by Townes and co-workers in 1954. (This was the maser—microwave amplification ) In 1958 Schawlow and Townes de-... 

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. 

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