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Using a polarizer in landscape photography is often advised. And with reason: colors will be enhanced, reflections in water and on the leaves can be removed, and skies can turn deep blue. But it is not advisable to use a polarizer as a standard filter, because there are situations when it can turn against you.

Refraction occurs when a beam of light passes from one material into another material. At the surface of the two materials, the path of the beam changes its direction. Since these two refracted rays are polarized with a perpendicular orientation, a polarizing filter can be used to completely block one of the images.

Hence the light that passes through the sheet is polarised. The end result is that for any light aligned in the direction of conduction the polariser absorbs the light and converts it to heat.

Brewster’s angle (also known as the polarization angle) is an angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection.

The special angle of incidence that produces a 90o angle between the reflected and refracted ray is called the Brewster angle, θp. A little geometry shows that tan(θp) = n2/n1. Why is the reflected light polarized?

According to the law, the tangent of the polarizing angle is equal to the refractive index of the medium.

Answer. It has been observed experimentally that the reflected and refracted rays are at right angles to each other, when the light is incident at polarising angle. Thus, The tangent of the polarising angle is numerically equal to the refractive index of the medium.

If light strikes an interface so that there is a 90o angle between the reflected and refracted rays, the reflected light will be linearly polarized. The direction of polarization (the way the electric field vectors point)is parallel to the plane of the interface.

Polarization (also polarisation) is a property applying to transverse waves that specifies the geometrical orientation of the oscillations. In linear polarization, the fields oscillate in a single direction. In circular or elliptical polarization, the fields rotate at a constant rate in a plane as the wave travels.

Polarization happens when people become divided into contrasting groups. Outside science, polarization usually refers to how people think, especially when two views emerge that drive people apart, kind of like two opposing magnets.

Types of Polarization

• Linear polarization.
• Circular polarization.
• Elliptical polarization.

P-polarized (from the German parallel) light has an electric field polarized parallel to the plane of incidence, while s-polarized (from the German senkrecht) light is perpendicular to this plane.

Linearly polarised light is the light wave in which the vibration of electric field vectors are confined in one plane and parallel to one unique direction.

Circularly polarized light can be converted into linearly polarized light by passing it through a quarter-waveplate. Passing linearly polarized light through a quarter-waveplate with its axes at 45° to its polarization axis will convert it to circular polarization.

Most light sources emit unpolarized light, but there are several ways light can be polarized. One way to polarize light is by reflection. Light reflecting off a surface will tend to be polarized, with the direction of polarization (the way the electric field vectors point) being parallel to the plane of the interface.

In many, although not all, cases the output of a laser is polarized. This normally means a linear polarization state, where the electric field oscillates in a certain (stable) direction perpendicular to the propagation direction of the laser beam.

In gas lasers, many different modes may be excited in the cavity, but only modes that are not very lossy end up being amplified and emitted – this can result in a single polarization. However, there may be multiple modes with different polarizations that have this property, resulting in a more random polarization.

The usual way linear polarisation is measured is by shining polarised light onto a polarising filter, rotating that filter and then using Malus’ law to fit the data to a I0cos2(θbeam−θpolariser) shape. By finding the angular position of the intensity peak we can infer the angle of polarisation of the incoming beam.