2

Typically unpolarised light is shown like this: enter image description here

Basically, from what I've seen, unpolarised light is just a lot of overlapping individual light waves. However, if they truly overlapped, would their electric and magnetic fields not cancel out?

In the picture above, shouldn't there be a net electric field direction (or even 0 in this case - meaning no EM wave?), as $E$ fields can add (as evidenced by circular polarization)? Is it because this net direction would rapidly change throughout the light ray that it's considered non-polarised? But if this cancellation was true, wouldn't that mean that all the intensity and energy of the original waves have been "destroyed"?

John Hon
  • 2,384

2 Answers2

1

The different polarized components follow each other in time and therefore you can not add them all at a given moment.

Usual optical receiver has a large response time compared to the characteristic change time of the polarization and on average (temporal) the light is unpolarized.

Sorry for my english.

Vincent Fraticelli
  • 4,960
0

The unpolarizedness is in a time averaged sense.

At any instant, if you measure the electric field, you have a definite axis for it. But over time, this axis changes in the way described by your diagram such that there is no preferred axis.

Navneeth Ramakrishnan
  • 1,221