View Full Version : Anamorphic prisms- FA or mode correction?

11-05-2010, 21:28
OK, so, really stupid question. O_o

I've done what I can to read up about these things, with not much luck.

I just want to know- are they for mode correction or for FA correction?

Some say they simply fix the highly-divergent fast axis, while others have said they circularize the beam.

So what's the case with these, then? Do you need seperate optics after the prisms to get a round beam profile, or do the prisms also fix up the beam profile as well as correcting the fast axis?

Thanks in advance.

11-05-2010, 23:51
I believe it is FA correction and I truly don't feel we are going to get a round beam out of these. Perfectly square is the best we can hope for in my opinion. I think we might want to start looking for ways to expand our greens a bit to match the red and blues a bit more.

11-06-2010, 00:23
Mmm, didn't think it'd work miracles with the beam profile. O_o

Anyway, I'd just be happy if the FA and SA have the same divergence. You could probably adjust your green out to match it, and the red too.

11-06-2010, 00:52
what reds and blues are you using that are bigger than greens ?
my problem is the other way round i have 640nm @.8mrad ,445 @1mrad, and a fat arsed green @1.5mrad

11-06-2010, 03:53
A tilted bi convex lens can go some way to circularising a beam.

11-06-2010, 21:22
Ahh, so it is for divergence correction.

Thanks for clearing that up.

I wasn't expecting miracles either, but if it's got less than 2mRad divergence, I'm happy.