Clear Description On Polarisation

In physics, polarisation can be described as a phenomenon caused because of the nature of the waves of electromagnetic radiation. One common example of electromagnetic waves is the sunlight travelling to the earth through a vacuum. Since these waves form an electric field, they are referred to as electromagnetic waves.  

Polarisation

Polarisation is one of the properties of transverse waves associated with the geometrical orientation of their oscillations. In other words, it is the property of transverse waves which tells about the direction of their oscillations. A polarised light wave oscillates only in one direction, while the non-polarised wave can oscillate in multiple directions. The process of transformation of the non-polarised waves into polarised waves is called polarisation.

Types of Polarisation 

There are mainly three different types of polarisation. These include – 

• Linear polarisation 

The first type of polarisation is linear polarisation, where the electric field of the light is only limited to a single plane through the direction of propagation.

• Circular polarisation

In the electric field of light, there are mainly two linear components perpendicular to one another so that their amplitudes are the same. In contrast, their phase is different between two. The occurring electric field’s propagation will be in a circular motion. 

• Elliptical polarisation

The electric field of the light follows the elliptical polarisation. The phase and the amplitude difference between both linear components are not the same. 

Methods used in the light polarisation 

There are several methods used in light polarisation – 

1. Polarisation by Reflection

• Polarisation by Transmission
• Polarisation by Refraction
• Polarisation by Scattering

2. Polarisation by scattering 

The electromagnetic waves produced by the movement of light through a medium are caused by the vibration of the medium’s atoms (also dust present in the medium). The light is scattered as a result of these waves radiating outward. Light waves are absorbed and re-emitted throughout the entire process. The scattered light is also called partial polarisation, and they cause glare by transmitting partially polarised light.

3. Polarisation by reflection

In the case of unpolarised light falling at a particular angle on a non-metallic surface, the surface reflects the polarised light. To regulate the magnitude of polarisation, angles of incidence and non-metallic surfaces play an important role in this process.

4. Polarisation by refraction 

The refraction of light is the act of changing the direction and speed of a light wave as it travels from one medium to another. In doing so, there is polarisation within the refracted beam. Refraction by polarisation is a phenomenon most frequently observed in perpendicular planes.

4. Polarisation by transmission 

A filter material with a special chemical composition is used in this method. The filters are called polaroids and block electromagnetic waves on one of their two axes. In a single plane, these polaroid filters let the light that is polarised transmit half of its vibrations. Polarised light has half the intensity.

Applications of polarisation

Some applications of polarisation include the following:

• Chemists who study organic molecules and establish their chirality are said to be practising chiral chemistry, a field of chemistry that uses polarised methods to accomplish this task.
• We can distinguish between longitudinal and transverse waves thanks to polarisation information.
• Stress analysis with polaroid filters is a common practice in the plastics industry.
• Three-dimensional films are created and displayed with the help of polarisation.
• A glare-reducing technology, polarisation is used in sunglasses to reduce glare and reflection.
• This method finds applications in seismology, the study of earthquakes.
• It is possible to improve the resolution of infrared spectroscopy data by employing polarisation.

Conclusion 

We come to the end of the topic description on polarisation with this. Polarisation can be described as a phenomenon caused because of the nature of the waves of electromagnetic radiation. One common example of electromagnetic waves is the sunlight travelling to the earth through a vacuum. Further, it is classified into three major parts, linear, circular, and elliptical polarisation, which we discussed. Also, a series of methods are used in light polarisation. We ended the topic with a detailed description of electromagnetic waves. We hope it has helped you attain a better understanding of the topic of Polarisation.