Based on Faraday effect, If a piece of glass is exposed to a magnetic field, it optically activates.As the linearly polarized light passes parallel to the applied magnetic field, the plane of light polarization rotates.
1- can we pass light through fiber optic and fiber optic works as glass?
2- in some sources I see the linearly polarized light should be circularly polarized,because left and right circular polarized light waves have different speeds in magnetic field, I dont know to use linear or circular polarized light?
The linearly polarized light mathematically can be presented as a superposition of equal amplitude of right and left circularly polarized light. Due to Faraday effect, the phase velocity of the right/left polarization light becomes different therefore they arrive with different phases and that effectively seen as rotation of superposition linear 'sum' light.
Nikolay Pavlov
according to attached file (paragragh 2: At the top of the column there is a circular polarizer that converts the two linearly-polarized light signals into right and left circular polarizations. ,is circular polarizer mandatory? or the linear light can be presented as a superposition of equal amplitude of right and left circularly polarized light?
another question in faraday effect a medium with specific verdet constant is necessary,can fiber optic passing light be supposed as the medium with specific verdet constant?
Shabnam Jamshidi Please check out the following work:
Article Theory for the Faraday effect in optical fiber
The conversion from linear polarization to circular is performed by so-called quarter plates ( they provide lambda/4 phase shift between different polarizations):
https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=8635
In that device the quarter plate is not necessary (the signal would be there anyway) however it suppresses the errors which can be caused e.g. by twisting of the fiber.
Nikolay Pavlov
1-in this device what is the benefit of circular polarizer ( the quarter plate)?
2- according to your answer "The linearly polarized light mathematically can be presented as a superposition of equal amplitude of right and left circularly polarized light. Due to Faraday effect, the phase velocity of the right/left polarization light becomes different therefore they arrive with different phases and that effectively seen as rotation of superposition linear 'sum' light." if the light is composed of equal amplitude of right and left circularly polarized light, so existence of circular polarizer is optional?
3- is it possible to pass the light through fiber optic and then light comes out of fiber optic and goes through the quarter plate and the again continue the way through fiber optic?
1- it suppresses the errors which can be caused e.g. by twisting of the fiber.
2- existence of circular polarizer is optional? -Yes
3- Yes, you can have a look at special setup E.G. https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=2161
Is faraday effect limited just to light wavelength (400-700 nm) or all electromagnetic wavelength?
what is the effect of wavelength on the result of rotation of polarization state?
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