# Polarization Of light

1. Jul 23, 2009

### abid220

Hey all,

Polarization of light is still confusing for me :-( i read alot but i couldn´t clear my concept . can any body of yous explain...

I would be very thankful.

Best regards
Abid

2. Jul 23, 2009

### tiny-tim

Welcome to PF!

Hi Abid! Welcome to PF!

Light is a vibration.

If the vibration is in a particular plane, then it is polarised in that plane (which will be perpendicular to the direction of the light)

If the vibration "spirals" round, then it is circularly or elliptically polarised.

3. Jul 23, 2009

### Andy Resnick

The polarization of light is defined at the instantaneous direction of the electric field vector. If the electric field is confined to a single direction, the light is said to be 'linearly polarized'. Of the electric field traces out a circle, the light is 'circularly polarized'. There's also elliptical polarization states and 'randomly polarized' (sometimes called unpolarized) light. Given a spatially extended electromagnetic wave, 'polarization' has implications for coherence and is also a statistical measure of the EM field.

Any(*) polarization state can be decomposed into two orthogonal states: vertical and horizontal linear states, right- and left-handed circular states, s- and p- states, etc.

(*)-the light must be completely polarized, not partially or unpolarized.

Does that help?

4. Jul 24, 2009

### abid220

Actually, i m new to optics, and it very difficult for me to imigine theoritically and experimentally...... could you plz give us some simple example to imigine...
we are working on Ellipsometer, which apply polarize light on the material and than check it change in polarization, in order to study the material

5. Jul 24, 2009

### Cyrus

http://www.molecularexpressions.com/optics/lightandcolor/images/polarizationfigure1.jpg

Does this help?

6. Jul 24, 2009

### Andy Resnick

It's not clear if you are having problems with the optics concepts, or the matter-EM interaction.

The classic text is "ellipsometry and polarized light" by Azzam and Bashara. But in general Jones matrices suffice to describe the interaction- read up on those.