Linear polarized light and polarisation

[Gavroy]

hi

if you have linear polarized light and you have a metal grid and the angle between the e-vector and the metal grid is 30°. now you split up the e-vector in one component parallel and one component perpendicular to the metal grid. okay. so the component of the wave, that survives this prodcedure is the component perpendicular to the metal grid that has an angle of 90°-30°=60° to the initial wave. ( in the opposite direction)

my problem is: that if you now have another grid, that has a component that is parallel to the initial wave, this original wave would have not been able to pass the grid. but, if you regard the wave with the shift of 60°. there is a component perpendicular to the initial wave that could also pass this grid.

my only question is: are these considerations all right so far? cause i am a little bit wondered about this fact...

 

[Born2bwire]

You don't really have a component that is perpendicular to the grid though unless you are talking about one that is normal to the grid's plane. There are two modes, transverse magnetic and transverse electric, to the grid's plane. So in the TM mode, the electric field must lie in the plane of the grid and so you can always decompose the electric field into two components that point along the two axes of the grid.

In the TE mode, the electric field has a component that lies in the plane of the grid (which we know will be canceled out via above) and one that lies perpendicular to the grid. But if the normal component would to pass through, then this means that the transmitted radiation could only travel along the metal grid (because in an open isotropic medium EM waves are transverse to the direction of propagation). So now, if it could exist (which it doesn't, well in general it doesn't) you can only have a transmitted surface wave.

So either way, you cannot have transmission of the electromagnetic wave through a grid provided that the grid is dense enough and has a high enough conductivity to extinguish the wave.

EDIT: Are you talking about a grid or a grating?

 

[Antiphon]

hi

if you have linear polarized light and you have a metal grid and the angle between the e-vector and the metal grid is 30°. now you split up the e-vector in one component parallel and one component perpendicular to the metal grid. okay. so the component of the wave, that survives this prodcedure is the component perpendicular to the metal grid that has an angle of 90°-30°=60° to the initial wave. ( in the opposite direction)

my problem is: that if you now have another grid, that has a component that is parallel to the initial wave, this original wave would have not been able to pass the grid. but, if you regard the wave with the shift of 60°. there is a component perpendicular to the initial wave that could also pass this grid.

my only question is: are these considerations all right so far? cause i am a little bit wondered about this fact...

It's all correct. Each polarizer launches a new wave which is how multiple polarizers can rotate the original polarization by 90 degrees.

 

[Gavroy]

It's all correct. Each polarizer launches a new wave which is how multiple polarizers can rotate the original polarization by 90 degrees.

thank you that was exactly what i wanted to know...

 

[sardar]

Yes, your considerations are correct so far. This phenomenon is known as polarization and it occurs when light waves are confined to vibrate in a certain direction, either parallel or perpendicular to a surface. When a polarized light wave encounters another surface, such as the metal grid in this case, the wave is either transmitted or reflected depending on the orientation of the surface and the direction of the wave's polarization. This is because the electric field of the wave is only allowed to vibrate in a certain direction, and if the surface is not aligned with this direction, the wave will not be able to pass through it. This is why polarized sunglasses can reduce glare from surfaces like water, as they only allow light waves vibrating in a certain direction to pass through, reducing the overall brightness and glare. So in your scenario, the initial wave would not be able to pass through the second grid if it is oriented in the same direction as the first grid, but the component that is perpendicular to the initial wave and has an angle of 60° can pass through the second grid. This is why linear polarized light is often used in applications such as communication and imaging, as it can selectively transmit or block certain components of a light wave.