Scattering of Light
Scattering of light is the phenomenon in which light is deviated in all directions when it interacts with the atoms and molecules of the atmosphere. The particles that cause this deviation are called scatterers. Thus, the beam of light gets redirected when it passes through a medium.
Types of scattering
When light interacts with particles of a medium, different types of scattering occur depending on the energy of the incident and scattered light.
Elastic scattering
Elastic scattering occurs when the energy of the incident light and scattered light remain the same. Only the direction of light changes, but its wavelength does not change.
Inelastic scattering
Inelastic scattering occurs when the energy of the incident light and scattered light are not the same. The nature and size of the scatterer result in different types of scattering.
Types of scattering
The following are the types of inelastic scattering:
- Rayleigh scattering
- Mie scattering
- Tyndall scattering
- Raman scattering
Rayleigh scattering
Rayleigh scattering is the scattering of sunlight by the atoms or molecules of gases present in the Earth’s atmosphere. According to Rayleigh’s law, the amount of scattering is inversely proportional to the fourth power of wavelength\(\frac{1}{\lambda ^{4}}\). Hence, shorter wavelengths are scattered more than longer wavelengths.
Mie scattering
Mie scattering occurs when the size of the scattering particles is similar to or larger than the wavelength of light. It is almost independent of wavelength. This type of scattering is caused by dust, smoke, pollen, and water droplets present in the lower atmosphere.
Tyndall scattering (Tyndall effect)
Tyndall scattering is the scattering of light by colloidal or fine suspended particles in a medium. Due to this effect, the path of a light beam becomes visible when it passes through dusty air or colloidal solutions.
Raman scattering
Raman scattering occurs when a beam of monochromatic light passes through a gas, liquid, or transparent solid, and a part of the light is scattered with a change in wavelength or frequency. The scattered light contains Rayleigh lines (same frequency) and Raman lines (different frequencies).