Absorption coefficient

Definition: The absorption coefficient of a medium, mu_a is related to the probability of a photon to be absorbed by the medium after it travels some distance in the medium; more precisely, it is the rate of photon absorption per unit length in the medium. The absorption coefficient depends on medium composition and light wavelength. The inverse of the absorption coefficient, known as the absorption length, l_a can be understood as the distance traveled by a photon before its probability of not being absorbed in the medium has decreased by e^{-1}. Quantitatively, the absorption coefficient can be related with the light intensity attenuation as it traverses the medium. Let I represent the intensity at any point of the path, such that the differential intensity is dI, dl a differential length along the path of the radiation. Then frac{dI}{dl}=-mu_al , and the constant mu_{a} is known as the absorption coefficient.Definition: The absorption coefficient of a medium, mu_a is related to the probability of a photon to be absorbed by the medium after it travels some distance in the medium; more precisely, it is the rate of photon absorption per unit length in the medium. The absorption coefficient depends on medium composition and light wavelength. The inverse of the absorption coefficient, known as the absorption length, l_a can be understood as the distance traveled by a photon before its probability of not being absorbed in the medium has decreased by e^{-1}. Quantitatively, the absorption coefficient can be related with the light intensity attenuation as it traverses the medium. Let I represent the intensity at any point of the path, such that the differential intensity is dI, dl a differential length along the path of the radiation. Then frac{dI}{dl}=-mu_al , and the constant mu_{a} is known as the absorption coefficient.

Alternative definition: At any given point in the path of radiation, the Absorption Coefficient determines the fractional reduction in intensity per unit length of the path.

Synonym:

References: https://doi.org/10.1036/1097-8542.001600

Related terms: Absorption  

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