S Polarized vs P Polarized:Comparative Analysis

A wave can undergo many phenomena such as reflection, refraction, diffraction, and dispersion, which you already know from our previous articles. One among such wave phenomena is polarization.

Polarization is the property of the electromagnetic wave that confines the shattered waves into a single direction. The polarization is further classified into s-polarized and p-polarized by considering the behavior of waves on the plane of propagation. This post is concerned with a comparative analysis of s polarized vs p polarized wave.

Comparison of s polarized vs p polarized wave

Not all wave has the ability to undergo polarization. There are some restrictions for the wave to undergo polarization; such properties are discussed in the table below, giving a brief comparison of s polarized vs p polarized wave.

S polarizedP polarized
DefinitionWhen electromagnetic radiation is incident on a plane medium, the polarization of radiation will occur perpendicular to the plane of incidence; such polarization is called as s polarized.When an electromagnetic radiation incident on a plane medium, the polarization of the radiation occurs parallel to the plane of incidence, such polarization is called p polarized.
Nature of angle of incidenceIn most cases, when an incident wave is made to fall on the polarizer at an angle equal to Brewster’s angle, one can achieve an s-polarized wave.At Brewster’s angle, we cannot achieve the p polarized wave. The angle of incidence must be greater or less than Brewster’s angle.
Variation of Brewster’s angleThe Brewster’s angle does not affect by the s-polarization; it remains as usual with the incident wave.The Brewster’s angle vanishes as the wave incident on the plane medium
Reflective abilityAs the angle of incidence increases, the ability to reflect the wave also increases in s polarized wave.There will be no reflection occurring at Brewster’s angle. Almost up to 90°, the reflection is less. As the angle incidence increases above 90°, the reflective ability slightly increases.
Phase differenceThere will always be a 180° phase shift of the polarized wave with the incident wave, Brewster’s angle does not matter for the phase difference in s polarized wave.In the case of a p polarized wave above Brewster’s angle, the phase difference can be seen in a p polarized wave. There will be a 180° phase shift with the incident wave, but below the Brewster’s, the polarized wave is in phase with the incident wave.
The amplitude of the reflected waveThe amplitude of the reflected wave increases with the incidence angle in s polarized wave.In the case of a p polarized wave also the amplitude of the reflected ray gradually increases with the angle of incidence.
Comparative analysis of s polarized vs p polarized wave
Image credits: Image by WikiImages from Pixabay 
s polarized vs p polarized
Free body diagram illustrating s polarized vs p polarized wave

Facts to be remember

  • S polarized, and P polarized waves are essential properties for the reflection and transmission of waves in the medium.
  • The terms s and prefers to their alignment in the medium. S refers to Senkrecht, which is derived from the German word that means perpendicular or normal, whereas P refers to parallel, based on the alignment of wave incident on the medium.
  • In the diffraction grating, the s polarized wave refers to the perpendicular polarization with respect to the lines on the grating, not to the perpendicular to the plane of incidence.
  • If you consider the prism of Brewster’s angle, the reflected ray staying in the horizontal direction is considered to be s polarized because if you tilt the prism, the reflected rays go upward, but it does not change.
  • The nature of polarization as s polarized and p polarized is considered according to the direction polarization with respect to the plane of incidence. Thus s and p polarized waves must be relevant to the plane of incidence.

Frequently asked questions

What is meant by polarization?

When a wave undergoes any phenomena such as reflection, refraction, diffraction, etc., the waves can propagate in any direction. These waves have not bounded to propagate in a particular direction.

Polarization is the process applied to the waves to bring all the scattered waves in a single proper direction. The longitudinal waves cannot undergo polarization; only the transverse wave can be polarized. The polarization involves the transverse waves to specify the geometrical orientation.

What are the conditions required for polarization?

A wave has to possess several properties to undergo polarization. Some of such conditions are listed below.

  • A wave should be a transverse wave to undergo polarization.
  • The wave must be coherent, and the phase difference of the incident wave should be constant.
  • The medium of propagation should be homogenous.
  • The wave should be perpendicular to the direction of propagation.

Can sound waves undergo polarization?

We have understood that only transverse waves can undergo polarisation from the definition of polarization. However, the sound wave is a longitudinal wave; it cannot undergo polarization.

Sound waves cannot undergo polarization because the sound wave vibrates only in a single direction, along the direction of propagation. Thus it becomes quite difficult to confine the wave. Hence sound waves cannot be polarized.

An only transverse waves can undergo polarization; explain why?

A wave is said to be transverse when the wave oscillates along the path at a right angle to the direction of propagation.

The transverse wave can vibrate in the direction perpendicular to the energy level so that vibration can occur in all the perpendicular directions, and it becomes easy to confine them. So for transverse waves, there could be two orthogonal directions for propagation in three-dimensional space.

What is meant by Brewster’s angle?                             

When a light incident on a transparent dielectric medium, the maximum amount of light get polarized at a certain angle, that angle of incidence is nothing but Brewster’s angle.

Brewster’s angle is more precisely stated as it is an angle of incidence at which the wave can perfectly transmit along the transparent surface without letting back reflection of the wave so that one can get the maximum amount of polarized wave.

What are different types of polarization?

Depending on the transverse and longitudinal motion of waves and their behavior in the medium, the polarization is divided into three kinds they are

  • Linearly polarized wave – the wave is restricted to a single plane along the direction of wave propagation.
  • Circularly polarized wave – the wave has two linear components perpendicular to each other. Their amplitudes are equal with a phase difference of π/2, resulting in the circular motion of the polarized wave.
  • Elliptically polarized wave – the wave has two linear components whose amplitudes and phase differences are unequal, resulting in the elliptical motion of the polarized wave
Scroll to Top