light polarization: what is it?

[gib65]

What does it mean to polarize light?

[theCPE]

A filter that polarizes light allows only the light vibrating in a specific plane to pass through.

 

Once the light has passed through that filter it is polarized to one plane of vibration.

[Klaynos]

The polarisation state of light is the alignment of the vector of the E field in the photons.

 

So for linearly polarised light, if you say that it is polarised horizontally then the E field is pointing horizontally (and the B field vertically).

 

There are many words used to describe polarisation, parallel, transverse, p state, s state, with a set number of degrees etc...

 

There is also elliptically (or circularly) polarised light where the fields are moving in direction.

[gib65]

Is it fair to imagine polarized light as waves literally going "left" and "right" (supposing it was horizontal)? I always imagined the peaks and trough of light waves to be more like those of sound waves where it was more like intervals of dense air followed by not so dense air, which sort of makes the whole idea of polarization meaningless. Is this wrong?

[theCPE]

Yeh, I don't believe you can view light exactly as sound waves (with peaks and troughs of dense or no so dense air).

 

Plus, light exists as a duality of waves and particles.

 

A really neat experiment (not sure it would help you much though) is to use polarizing lenses and orient them at 90 degree angles and shine light through them, adjusting the lenses and watching the light appear and disappear.

[grifter]

Yeh, I don't believe you can view light exactly as sound waves (with peaks and troughs of dense or no so dense air).

 

since sound waves are longitudinal, its impossible to relate them to light waves, as with sound waves, the direction of oscillation is along the direction of travel. so polarization cannot occur....

 

think of a normal light "wave" traveling in many planes (like the points on a compass) then once it has been polarized think of the light traveling only in one plane i.e.

 

----\|/----> this is unpolarized (direction of travel -->) (ignore the dots)

....../|\

 

 

........./

------/-----> this light is polarized (direction of travel -->) (ignore dots)

......./

 

try not to think of my random lines as light emitting from a central point, as that is NOTHING TO DO WITH POLARIZATION instead thing of the waves traveling along the screen in this direction -----> instead of light traveling in many different planes (unpolarized) think of the light in a single plain (polarized) i hope this poor description helps, for a better worded version with images that will have more meaning than mine check this link:

http://en.wikipedia.org/wiki/Polarization

[swansont]

The electic and magnetic fields are perpendicular to the direction of travel for the light (and perpendicular to each other). Polarization tells you the specific orientation/behavior of the direction of E.