Lord Rayleigh (12th November 1842) was discovered rayleigh scattering. We know the phenomenon of light that is reflection and refraction. The particles in the atmosphere called scatter because when the light is entered into the atmosphere then these particles will be scattered into lights. This phenomenon of refraction can be called as a scattering of light. There are two types of scatterings like elastic and non-elastic. The rayleigh, Mie, and non-selective scatterings are elastic scatterings and the Brillou, Raman, In-elastic X-ray, Compton is the in-elastic scatterings. In this article, one type of elastic scattering namely Rayleigh is discussed briefly.
What is Rayleigh Scattering?
Definition: The rayleigh is the scattering of the molecules by the gas in the atmosphere of the earth. The scattering strength depends on the light wavelength and also on the particle size. Due to density & compositional variations and fluctuation in refractive index, this scattering occurs because of the inhomogeneities.
Scattering of Light
All most all objects scatter lights, that means the reflected light that illuminates them in all direction. The rayleigh or linear scattering is caused by the interference with particles smaller than the wavelength of the light. The light travels through the fiber interacts with the particles and then scattered in all directions, it causes energy losses and attenuation during the data transmission.
Scattering Losses
The loss is proportional to the λ4 and to the P(r), A(r), and r. The mathematical expression is given by
αR = 1/λ4 ∫0+∞ A(r) P(r)rdr / ∫0+∞ P(r)rdr
Where A(r) = Linear scattering coefficient, P(r) = Light intensity propagation, 'r' = Radial distance.
Difference Between Rayleigh and Mie Scattering
The difference between these two is discussed below.
| S.NO | Rayleigh or Linear Scattering | Mie Scattering |
|---|---|---|
| 1 | In Rayleigh or linear scattering, the particle size is less than the wavelength | In Mie scattering, the particle size is greater than the wavelength |
| 2 | The dependence on wavelength is strong in this scattering | The dependence on wavelength is weak in this scattering |
| 3 | It is a linear scattering | It is also a linear scattering |
| 4 | The kind of particles in this scattering is air molecules | The kind of particles in Mie scattering is smoke, fume, and haze |
| 5 | The air molecule particle diameter is 0.0001 to 0.001 micrometers and the phenomena of air molecules are blue sky and red sunsets | The aerosols particle diameter in Mie scattering is from 0.01 to 1.0 micrometers and the phenomena of aerosols (pollutants) are brownish smog |
Rayleigh Scattering in Optical Fiber
The optical fiber is thin, flexible, and transparent of optically pure silica glass and plastic. The optical fibers are faster, impervious to electromagnetic interference, cannot catch on fire and the signal loss is less. When a beam of light that carries signals travels from the fiber optics, then the strength of the light becomes lower, this loss of light power is generally called attenuation. An attenuation has to be a top priority for many engineers to consider selecting and handling fiber optics.
FAQs
1). What causes Rayleigh or linear scattering?
The causes of rayleigh or linear scattering are, it results from inhomogeneities in the cladding and core. The density & compositional variations and fluctuation in refractive index are the problems that occur because of the inhomogeneities.
2). Who discovered Rayleigh scattering?
John William Strut was discovered.
3). What is the difference between Rayleigh and Mie scattering?
In the Rayleigh or linear scattering, the size of the scattering particles is smaller than the radiation wavelength and in the Mie-scattering the size of the scattering particles and the wavelength of radiation is the same.
4). What are the three types of scattering?
The three types of scattering are the rayleigh, non-selective scattering, and the Mie scattering.
5). What is the Rayleigh ratio?
The rayleigh ratio is one of the parameters which is used for the light scattering measurements.
In this article, an overview of Rayleigh Scattering or linear scattering, scattering of light, scattering losses, and the difference between Rayleigh and Mie scattering are discussed. Here is a question for what are the causes of Mie scattering?