Sources of light

A source of light for excitation. Surfece studies generally require a continuous or pulsed laser. A dye or Tlisapphire laser is used if tunability is needed. 

The source of light emission. Each individual animal in a colony of Pyrosoma has two groups of luminous cells at the entrance to the branchial sac (Herring, 1978a). The luminous cells contain tubular inclusions whose identity has been a matter of dispute for nearly a century. Buchner (1914) originally suggested that the inclusions were symbiotic luminous bacteria. However, efforts to cultivate luminous bacteria from the luminous cells of Pyrosoma consistently failed. In... 

Fig. 3.—Diagram of instrument, showing dumbbell assembly mounted between pole pieces of two small permanent magnets, source of light, and scale.

Free Electron Lasers and Other Advanced Sources of Light Scientific Research Opportunities, National Research Council, National Academy Press, Washington, D.C., 1994. 

At present time, these studies cannot be carried out, due to the short lifetimes involved, but with more intense sources of light it may be possible to reduce the measurement time enabling the measurement of 9 in the millisecond range with FTIR ellipsometry. 

Atomic absorption completely replaced OES in archaeological chemistry during the 1980s, and differs from it in a number of ways. Firstly, it is primarily a solution-based technique, therefore requiring solid samples to be dissolved prior to analysis. Secondly, it is based on the absorption of light by atomized samples in a flame, in contrast to OES which is based on emission. Because of this, AAS requires a source of light that has a wavelength... 

Depending on the type of laser used, this energy can come from a source of light, an electrical discharge or via chemical reactions. 

Beckman Instruments, one of the pioneers in Analytical Instruments and dominating this field since 50 years, has come up with their latest Beckman DU Series 60 Spectrophotometer, which essentially makes use of two different sources of light, namely ... 

Because there is no phase relation between the light emitted by different molecules, fluorescence can be considered as the result of three independent sources of light polarized along three perpendicular axis Ox, Oy, Oz without any phase relation between them. Ix, Iy, Iz are the intensities of these sources, and the total intensity is I = Ix + Iy + Iz. The values of the intensity components depend on the polarization of the incident light and on the depolarization processes. Application of the Curie symmetry principle (an effect cannot be more dissymmetric than the... 

Instead of glowbars, as used in MIR, tungsten halogen lamps are the sources of light. The detectors are solid-state semiconductors such as lead sulfide (PbS) or indium gallium arsenide (InGaAs). These are orders of magnitude quieter than typical MIR detectors and often more sensitive. 

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