Polarization

[Ashish]

In order to show unpolarized light we use the

 

 

 

 

can you tell me please about what this arrow on the unpolarized represent

 

whether it represent electric field or what?

[insane_alien]

either electric or magnetic field, it doesn't really matter.

[Ashish]

can you tell me why?

 

I've read its electric field

[Klaynos]

The direction of the electric field vector is the definition of polarisation.

[swansont]

By convention it's the electric field; the magnetic field will always be at 90º so there's no need to depict it.

 

 

Edit: Gah! One minute late! Kurse you, Klaynos!

[timo]

I have a follow-up question on polarization of light. Assume I want to polarize microwaves with a metal grate. Assume the grate is oriented such that the bars of the grate are vertically aligned. Staying in the definition above: What will be the polarization of the beam of microwaves after the grate - and why?

[Klaynos]

I think... Perpendicular to the grating, the E field induced a charge in the grating along it's axis, and gets absorbed through non-radiative damping. I wonder though about the diffraction through these slits, or if they're below the diffraction limit, the surface plasmon polaritons you would create and their associated fields...

 

I will check with a microwave physicist in the morning

[swansont]

Apply the boundary conditions. The perpendicular component of the field has to go to zero for a conductor where there is no net charge, and the parallel component suffers no discontinuity. This assumes that the perpendicular direction can't support the wave, i.e. it's smaller than the wavelength.