Light scattering by particles

Light scattering by particles - part of computational electromagnetics dealing with single particle scattering, single scattering albedo, and absorption of electromagnetic radiation.

Maxwell's equations are the the basis of theoretical and computational methods. In case of geometries for which analytical solutions are known (such as spheres, cluster of spheres, infinite cylinders), the solutions are typically calculated in terms of infinite series. In case of more complex geometries and for inhomogeneous particles the original Maxwell's equations are discretized and solved. Multiple-scattering effects are treated by radiative transfer techniques (see, e.g. atmospheric radiative transfer codes).

Rayleigh scattering

Rayleigh scattering regime is the scattering of light, or other electromagnetic radiation, by particles much smaller than the wavelength of the light. Relative size of a scattering particle is defined by the ratio of its characteristic dimension and wavelength :$x\; =\; frac\{2\; pi\; r\}\; \{lambda\}$. Rayleigh scattering can be defined as scattering in small size parameter regime .

ingle spheres - Mie method

Scattering from any spherical particles with arbitrary size parameter is explained by the Mie theory. Mie theory, also called Lorenz-Mie theory or Lorenz-Mie-Debye theory, is a complete analytical solution of Maxwell's equations for the scattering of electromagnetic radiation by spherical particles (Bohren and Huffman, 1998).

For more complex shapes such as coated spheres, multispheres, spheroids, and infinite cylinders there are extensions which express the solution in terms of infinite series.

Non-spherical particles

There are several techniques for computing scattering of radiation by particles of arbitrary shape (see review in Mishchenko, et al. , 2000).

Discrete dipole approximation

The discrete dipole approximation is an approximation of the continuum target by a finite array of polarizable points. The points acquire dipole moments in response to the local electric field. The dipoles of these points interact with one another via their electric fields.

ee also

*List of light scattering codes
*Dynamic light scattering
*Mie theory
*Discrete dipole approximation - a technique to solve light scattering on non-spherical particles.
*Finite-difference time-domain method
*Scattering

References

*Barber,P.W. and S.C. Hill, Light scattering by particles : computational methods, Singapore ; Teaneck, N.J., World Scientific, c1990, 261 p.+ 2 computer disks (3 1/2 in.), ISBN 9971508133, ISBN 997150832X (pbk.)

*Bohren, Craig F. and Donald R. Huffman, Title Absorption and scattering of light by small particles, New York : Wiley, 1998, 530 p., ISBN 0471293407, ISBN 9780471293408

*Hulst, H. C. van de, Light scattering by small particles, New York, Dover Publications, 1981, 470 p., ISBN 0486642283.

*Kerker, Milton, The scattering of light, and other electromagnetic radiation, New York, Academic Press, 1969, 666 p.

*Mishchenko, Michael I., Joop W. Hovenier, Larry D. Travis, Light scattering by nonspherical particles: theory, measurements, and applications, San Diego : Academic Press, 2000, 690 p., ISBN 0124986609.

*Stratton, Julius Adams, Electromagnetic theory, New York, London, McGraw-Hill book company, inc., 1941. 615 p.