Wednesday, 26 October 2016

electromagnetism - In which direction due to a polarizing grid the photon's electric field is oriented?


After a photon passes the slit, is it's electric field oriented perpendicular or parallel to the slit and why this is so?




Answer



Wire grid polarisers allow radiation to pass that has it's electric field polarised perpendicularly to the direction of the wires.


The explanation is that the component of the light polarised parallel to the wires sees the grid as if it were a solid conductor and therefore most of it is reflected and the rest absorbed in the first couple of skin depths.


In order to act like this the grid spacing must be smaller than the wavelength. I guess this is why microwave ovens have a mesh on the door with wires in two perpendicular directions.


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