Measuring the Polarisation of Light

In summary, the question is about which component of linearly polarised light is measured when using a polarising filter, specifically the oscillating electric or magnetic field. The Wikipedia page on polarizers, specifically the section on absorptive polarizers, may provide further information on this topic.
  • #1
Miss_Astro
15
0
Maybe this is a trivial question, I'm not sure, but when you measure linearly polarised light, such as that in the CMB which component of the light is 'measured'.

By this I mean is it the oscillating electric field or the oscillating magnetic field that is oscillating in the direction of the polarising filter. Of course the E and B fields (not to be confused with E and B modes) cannot occur independently as it is an 'Electromagnetic wave' but as they are perpendicular the polarising filter can then only lie in the direction of the oscillations of one of the components.
 
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  • #2
Please read http://en.wikipedia.org/wiki/Polarizer

If you are talking about Polaroid films, then you might be interested in the 6th paragraph in the section called "Absorptive polarizers"
 

1. What is polarisation of light?

Polarisation of light refers to the orientation of the electric field in an electromagnetic wave. It is a property of light that can be described as the direction in which the electric field oscillates. Light can be polarised in various orientations such as horizontal, vertical, or diagonal.

2. How is the polarisation of light measured?

The polarisation of light can be measured using a polarimeter, which is a specialized instrument that measures the angle and intensity of polarized light. Another common method is using a polarizing filter, which only allows light of a specific orientation to pass through. By rotating the filter and measuring the intensity of light passing through, the polarisation can be determined.

3. What are some applications of measuring the polarisation of light?

Measuring the polarisation of light is important in various fields such as optics, astronomy, and telecommunications. It is used in the production of polarizing lenses for sunglasses and camera filters. In astronomy, it helps in studying the properties of light from celestial objects. In telecommunications, it is used to improve signal transmission and reduce interference.

4. How does the polarisation of light affect its properties?

The polarisation of light affects its properties in several ways. For example, polarised light can become unpolarized when passing through certain materials or when reflected from certain surfaces. It can also be rotated or filtered by other materials, which can impact its intensity and direction.

5. Can light of any wavelength be polarised?

Yes, light of any wavelength can be polarised. However, the degree of polarisation may vary depending on the wavelength and the materials it interacts with. For example, visible light can be polarised by passing through certain materials, while radio waves can be polarised by reflecting off certain surfaces.

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