Re: Laser light

[rshotwel@ivy.tec.in.us (Allen Shotwell)]

> Bill and David,
> 	I think you both need to give a short glossary of your terms.  I
> hear what you both are saying and I partially agree with both of you, but
> I am still confused.  I hope I'm not jumping out of my league here and
> these may sound stupid but...
>
> A couple questions:
> 1)  Isn't the "speckle" we see when a laser strikes a surface, just say an
> index card, caused by the interference of the "in step", same phase,
> photons as they reflect off the surface?
>
> 2)  If the photons aren't in phase, then why does a 1/4 wave plate do what
> it does to a laser beam?
>
> 3)  Bill, are you saying that all the photons have the same frequency, but
> are not necessarily in phase with each other?
>
> 4)  What is the purpose of the brewster window and why don't small HeNe
> lasers have them?
>
> I know the answer to some of these but hearing your explanations will help
> me figure out what you guys are trying to say.  Just playing Devil's
> advocate in a way.


Still working on answers for 1-3 (and comments for Bill and David), but I
can answer #4 sort of "off the cuff" which is probably a bad idea.
Brewster's window is a polarizing tool used to produce linearly polarized
beams. Some small HenE have one but most don't (they are therefore
unpolarized beams).
R. Allen Shotwell
Chair, Science and Math
Ivy Tech State College
Terre Haute, IN