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It is in essence a quantum interference effect that permits the propagation of light through an otherwise opaque atomic medium. [ 1 ] Observation of EIT involves two optical fields (highly coherent light sources, such as lasers ) which are tuned to interact with three quantum states of a material.
Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light. In radiative transfer , it describes the absorption and scattering of radiation in a medium , such as a plasma , dielectric , shielding material , glass, etc.
The vacuum wavelength (the wavelength that a wave of this frequency would have if it were propagating in vacuum) is =, where c is the speed of light in vacuum. In the absence of attenuation, the index of refraction (also called refractive index ) is the ratio of these two wavelengths, i.e., n = λ 0 λ = c k ω . {\displaystyle n={\frac ...
Thomson scattering is a model for the effect of electromagnetic fields on electrons when the field energy is much less than the rest mass of the electron .In the model the electric field of the incident wave accelerates the charged particle, causing it, in turn, to emit radiation at the same frequency as the incident wave, and thus the wave is scattered.
When light traveling in a dense medium hits a boundary at a steep angle, the light will be completely reflected. This effect, called total internal reflection, is used in optical fibers to confine light in the core. Light travels along the fiber bouncing back and forth off of the boundary.
Kramers' opacity law describes the opacity of a medium in terms of the ambient density and temperature, assuming that the opacity is dominated by bound-free absorption (the absorption of light during ionization of a bound electron) or free-free absorption (the absorption of light when scattering a free ion, also called bremsstrahlung). [1]
Limb darkening is an optical effect seen in stars (including the Sun) and planets, where the central part of the disk appears brighter than the edge, or limb. [1] Its understanding offered early solar astronomers an opportunity to construct models with such gradients. This encouraged the development of the theory of radiative transfer.
Rough plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including visible light.. The optical window is the portion of the optical spectrum that is not blocked by the Earth's atmosphere.