Cathodoluminescence is most commonly experienced in everyday life as the light emission from the inner surface of the cathode ray tube in television sets and computer CRT monitors.

Cathodoluminescence is an optical and electrical phenomenon whereby a beam of electrons is generated by an electron gun and then impacts on a luminescent material such as a phosphor, causing the material to emit visible light.

** Cathodoluminescence, a result of being struck by an electron

Cathodoluminescence occurs because the impingement of a high energy electron beam onto a semiconductor will result in the promotion of electrons from the valence band into the conduction band, leaving behind a hole.

Cathodoluminescence is used in cathode ray tubes, photoluminescence in fluorescent lighting and plasma display panels, phosphorescence in safety signs and low energy lighting, fluorescence in pigments, inks, optical brighteners, safety clothing, and biological and medicinal analysis and diagnostics, chemoluminescence and bioluminescence in analysis, diagnostics and sensors, and electroluminescence in the burgeoning areas of light-emitting diodes ( LEDs / OLEDs ), displays and panel lighting.

Cathodoluminescence has been exploited as a probe to map the local density of states of planar dielectric photonic crystals and nanostructured photonic materials.

Cathodoluminescence and EBIC are referred to as " beam-injection " techniques, and are very powerful probes of the optoelectronic behavior of semiconductors, in particular for studying nanoscale features and defects.

* B. G. Yacobi and D. B. Holt, Cathodoluminescence Microscopy of Inorganic Solids, New York, Plenum ( 1990 )

* C. M. Parish and P. E. Russell, Scanning Cathodoluminescence Microscopy, in Advances in Imaging and Electron Physics, V. 147, ed.

The input light distributions considered are P-11 and P-20 phosphor emission and the so-called `` night light '' ( N.L. ) as given by H.W. Babcock and J. J. Johnson.

( The P-20 input is of interest because it corresponds roughly to the light emission of conventional X-ray fluorescent screens ).

After Bohr's use of Einstein's explanation of the photoelectric effect to relate energy levels in atoms with the wavelength of emitted light, the connection between the structure of electrons in atoms and the emission and absorption spectra of atoms became an increasingly useful tool in the understanding of electrons in atoms.

Arcturus is a type K1. 5 IIIpe orange giant star — the letters " pe " stand for " peculiar emission ," which indicates that the spectrum of light given off by the star is unusual and full of emission lines.

A low-intensity double-slit experiment was first performed by G. Taylor in 1909, by reducing the level of incident light until photon emission / absorption events were mostly nonoverlapping.

The matter-composition of the medium through which the light travels determines the nature of the absorption and emission spectrum.

Erbium-doped glasses or crystals can be used as optical amplification media, where erbium ( III ) ions are optically pumped at around 980 nm or 1480 nm and then radiate light at 1530 nm in stimulated emission.

The lost energy is converted into alternative forms such as heat, emission of low-energy secondary electrons and high-energy backscattered electrons, light emission ( cathodoluminescence ) or X-ray emission, which provide signals carrying information about the properties of the specimen surface, such as its topography and composition.

The gravitational weakening of light from high-gravity stars was predicted by John Michell in 1783 and Pierre-Simon Laplace in 1796, using Isaac Newton's concept of light corpuscles ( see: emission theory ) and who predicted that some stars would have a gravity so strong that light would not be able to escape.

Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation.

The mercury vapor emission spectrum is dominated by a short-wave UV line at 254 nm ( which provides most of the energy to the phosphors ), accompanied by visible light emission at 436 nm ( blue ), 546 nm ( green ) and 579 nm ( yellow-orange ).

These same visible lines, accompanied by the emission lines of trivalent europium and trivalent terbium, and further accompanied by the emission continuum of divalent europium in the blue region, comprise the more discontinuous light emission of the modern trichromatic phosphor systems used in many compact fluorescent lamp and traditional lamps where better color rendition is a goal.

The combination of the blue light that continues through the phosphor and the green to red fluorescence from the phosphors produces a net emission of white light.

Fluorescence in the life sciences is used generally as a non-destructive way of tracking or analysis of biological molecules by means of the fluorescent emission at a specific frequency where there is no background from the excitation light, as relatively few cellular components are naturally fluorescent ( called intrinsic or autofluorescence ).

The radio emission of a planet was first detected in 1955, when Burke and Franklin ( 1955 ) identified the origin of interference-like radio noise on their records at about 15 meters wave length as emission from Jupiter.

This technique ( named after their inventors ) is based on the line-broadening and self-reversal of emission lines from HCL when high current is applied.

Field ion microscopy techniques were initially construed as a modification of field emission, a technique which allows for a stream of electrons to be emitted from a sharp needle when subjected to a sufficiently high electric field (~ 3-6 V / nm ).

Thermionic emission occurs when the thermal energy exceeds the metal's work function, while field electron emission occurs when the electric field at the surface of the metal is high enough to cause tunneling, which results in the ejection of free electrons from the metal into the vacuum.

Cold electrodes can also spontaneously produce electron clouds via thermionic emission when small incandescent regions ( called cathode spots or anode spots ) are formed.

A similar phenomenon occurs for emission, which is seen when the emitting gas is glowing due to excitation of the atoms from any mechanism, including heat.

is the wavelength of the electromagnetic radiation ( photon ) when measured at the source of emission.

However, when the absorbed electromagnetic radiation is intense, it is possible for one electron to absorb two photons ; this two-photon absorption can lead to emission of radiation having a shorter wavelength than the absorbed radiation.

However, the International Prototype Metre remained the standard until 1960, when the eleventh CGPM defined the metre in the new International System of Units ( SI ) as equal to 1, 650, 763. 73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum.

Quantum dots ( nanoparticles with quantum confinement properties, such as size-tunable light emission ), when used in conjunction with MRI ( magnetic resonance imaging ), can produce exceptional images of tumor sites.

Attenuation correction: Attenuation occurs when photons emitted by the radiotracer inside the body are absorbed by intervening tissue between the detector and the emission of the photon.

Therefore, when the numbers of atoms in the ground and excited states are equal, the rate of stimulated emission is equal to the rate of absorption for a given radiation density.

In contrast fluorescence in materials is characterized by emission which ceases when the external illumination is removed.

Round observed light emission when electric current passed through silicon carbide crystals, the principle behind the light emitting diode.

However when a population inversion is present the rate of stimulated emission exceeds that of absorption, and a net optical amplification can be achieved.

# Flexible Mechanisms: The " flexibility " mechanisms which the United States had strongly favored when the Protocol was initially put together, including emissions trading ; Joint Implementation ( JI ); and the Clean Development Mechanism ( CDM ) which allow industrialized countries to fund emissions reduction activities in developing countries as an alternative to domestic emission reductions.

The parties also began discussing the post-Kyoto mechanism, on how to allocate emission reduction obligation following 2012, when the first commitment period ends.

The heated filament, or cathode, was capable of thermionic emission of electrons that would flow to the plate ( or anode ) when it was at a higher voltage.

They were the first to notice bright spectral emission lines when viewing the limb of the Sun without the aid of a total solar eclipse.

For instance, positron emission tomography ( PET ) studies report increases in dopamine release in the dorsal striatum ( as measured by displacement of endogenous dopamine by radioligands ) when participants are presented with potential rewards, such as the opportunity to gain money ( Koepp et al., 1998 ; Zald et al., 2004 ) or even when presented with food stimuli while in a state of hunger ( Volkow et al., 2002 ).