Emission, of radiation stimulated

The acronym LASER (Light Amplification via tire Stimulated Emission of Radiation) defines the process of amplification. For all intents and purjDoses tliis metliod was elegantly outlined by Einstein in 1917 [H] wherein he derived a treatment of the dynamic equilibrium of a material in a electromagnetic field absorbing and emitting photons. Key here is tire insight tliat, in addition to absorjDtion and spontaneous emission processes, in an excited system one can stimulate tire emission of a photon by interaction witli tire electromagnetic field. It is tliis stimulated emission process which lays tire conceptual foundation of tire laser. 

LASER, light amplification by stimulated emission of radiation... 

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. 

The term laser is an acronym constmcted from light amplification by stimulated emission of radiation. The first operating laser was produced in 1960 (1). This laser, which used a crystal of mby [12174A9-17, chromium-doped alumina, Al202 Cr, and emitted a pulsed beam of collimated red light, immediately aroused scientific interest. 

The word laser is an acronym for light amplification by the stimulated emission of radiation. Lasers of all kinds consist of several basic components an active medium, an outside energy source, and an optical cavity with carefully designed mirrors on both ends. One of the mirrors is 100 percent reflective... 

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... 

Radical chemistry has undergone something of a renaissance in recent years. The phenomenon of CIDNP has played an important part in this. The growing interest in the role of radical processes in biological systems may stimulate the application of CIDNP in even wider fields in the future. The development of a practical device for radiofrequency amplification by the stimulated emission of radiation (RASER) may well be one such application. 

Acronym for Microwave Amplification by Stimulated Emission of Radiation. ... 

International Union of Pure and Applied Chemistry International Union of Pure and Applied Physics Laser (Ablation) Micro Mass Spectrometry Light Amplification by Stimulated Emission of Radiation Liquid Chromatography... 

The word LASER is an acronym for Light Amplification by Stimulated Emission of Radiation. The physical process upon which lasers depend, stimulated emission, was first elucidated by Einstein in 1917 (1). Einstein showed that in quantized systems three processes involving photons must exist absorption, spontaneous emission, and stimulated emission. These may be represented as follows ... 

Lasers are devices for producing coherent light by way of stimulated emission. (Laser is an acronym for light amplification by stimulated emission of radiation.) In order to impose stimulated emission upon the system, it is necessary to bypass the equilibrium state, characterized by the Boltzmann law (Section 9.6.2), and arrange for more atoms to be in the excited-state E than there are in the ground-state E0. This state of affairs is called a population inversion and it is a necessary precursor to laser action. In addition, it must be possible to overcome the limitation upon the relative rate of spontaneous emission to stimulated emission, given above. Ways in which this can be achieved are described below, using the ruby laser and the neodymium laser as examples. 

In contrast to spontaneous emission, induced emission (also called stimulated emission) is coherent, i.e. all emitted photons have the same physical characteristics - they have the same direction, the same phase and the same polarization. These properties are characteristic of laser emission (L.A.S.E.R. = Light Amplification by Stimulated Emission of Radiation). The term induced emission comes from the fact that de-excitation is triggered by the interaction of an incident photon with an excited atom or molecule, which induces emission of photons having the same characteristics as those of the incident photon. 

Since the field of spectroscopic laser applications is so vast and the number of published papers exceedingly large, this review cannot be complete. However, the author has tried to give a reasonable survey of what has been done and to offer some ideas about what can be done in modem spectroscopy with such an interesting and stimulating invention as the laser (Light Amplification by Stimulated Emission of Radiation). 

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. 

Stimulated emission of photons. This process consists of electronic transitions from the excited energy level to the lower one stimulated by an external radiation of the appropriate frequency ( 2 - E fh and constitutes the basis of the laser (light amplification by stimulated emission of radiation) phenomenon. 

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). 

Considerable attention has been paid in the past few years to the study of both the absorption and emission spectra of the rare earths. This has been boosted further by the development of the new branch of physics, the Laser (light amplification through stimulated emission of radiation). The study of the optical spectra of ions yields valuable information about the energy levels of normal configurations and of excited states, and also about the nature of their environment. However, a detailed analysis of optical spectra demands a considerable knowledge of theoretical techniques. Recent advances in paramagnetic resonance techniques [479] have enabled us to understand the nature of the ground states of the rare earth ions in crystalline environments. 

The word laser stands for fight amplification by stimulated emission of radiation. The process of stimulated emission is the release of a photon by an excited atom or molecule under the impact of an incoming photon. This can be written as... 

Laser Diode (LD)—Light Amplification by Stimulated Emission of Radiation. An electro-optic device that produces coherent light with a narrow range of wavelengths, typically centered around 780 nm, 1320 nm, or 1550 nm. Lasers with wavelengths centered around 780 nm are commonly referred to as CD Lasers. 

The statistics of an assembly of light particles was studied by Bose, who found that ordinary statistics was not applicable. The laws for the new statistics were formulated jointly by Bose and Einstein, By studying an atom in statistical equilibrium, Einstein saw the necessity for the phenomenon of stimulated emission of radiation. This effect is, in the first place, extremely small, but it can be very much enhanced with a suitable apparatus, because of the new statistics. This led to the laser, a useful tool in present-day technology, which we owe to Einstein. 

The theory above has been applied in a variety of realistic situations. The range includes ionic conductance in aqueous solutions and molten alkali chlorides, damped spin-wave behaviour in paramagnetic systems, stimulated emission of radiation in masers, the fractional quantum Hall effect and quantum correlations in high-Tc cuprates and other non-BCS superconductors [4, 5, 7, 8, 14, 30]. In the next section we will also make some comments on the problem of long-range transcorrelations of protons in DNA [31]. 

Laser Laser is an acronym for Light Amplification by. Stimulated Emission of Radiation. Lasers are important in flow cytometry because, as a result of their coherent output, they are a means of illuminating cells with a compact, intense light beam that will produce fluorescence signals that are as bright as possible over a short time period. 

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