Mie scattering, named after the German physicist Gustav Mie, refers to the scattering of electromagnetic radiation (such as light) by spherical particles. Unlike Rayleigh scattering, which is applicable to particles much smaller than the wavelength of the incident radiation, Mie scattering is a more general scattering theory that can be applied to particles of any size.
Key points about Mie scattering:
Spherical particles: Mie scattering is specifically formulated for the scattering of electromagnetic waves by spherical particles. This can include particles in gases, liquids, or solids, as long as the particles have a size comparable to or larger than the wavelength of the incident radiation.
Wavelength dependency: Unlike Rayleigh scattering, which is more pronounced for shorter wavelengths (blue light is scattered more than red light), Mie scattering does not have a strong dependence on wavelength. It is applicable across a broad range of wavelengths.
Application to various fields: Mie scattering is used to explain phenomena observed in various fields, including atmospheric science, astronomy, optics, and remote sensing. It plays a role in the appearance of clouds, the colors of the sky, and the scattering of light by aerosols and particles in different media.
Scattering cross-section: The Mie theory provides a mathematical framework to calculate the scattering cross-section, which quantifies the probability of scattering per unit solid angle. The scattering cross-section is dependent on the size parameter, which is the ratio of the particle size to the wavelength of the incident radiation.
Scattering patterns: Mie scattering predicts distinctive scattering patterns, including forward scattering (in the direction of the incident light) and backward scattering (opposite to the incident light). The scattering pattern depends on the size and refractive index of the particles.
Rainbows and halos: Mie scattering is responsible for the formation of certain optical phenomena, such as halos around the sun or moon and the appearance of rainbows. The scattering of light by water droplets in the atmosphere contributes to these effects.
Complex refractive index: Mie scattering theory can be extended to account for particles with complex refractive indices, which is especially important when dealing with materials that exhibit both absorptive and scattering properties.
Mie scattering provides a valuable tool for understanding the interaction of electromagnetic radiation with particles of various sizes and is essential in interpreting observations in fields ranging from atmospheric physics to materials science.