Polarization issues.....

[MechEng3]

Would it be correct for one to assume that if a laser beam is sent through a PBS cube and obtaining the highest level of output would be optimal polarization for that laser? If said laser has an output of 290mw and you can get 250mw max out through the cube, is this considered around 78:1 polarization of this particular laser beam? I have studied this and it would seem ,that where the rubber meets the road, some lasers aren't truely 100:1 as advertised. Any additions/comments?

[dave]

It wouldn't surprise me.

We have had a few issues trying to do this with 2 high power greens, and the greens didn't have the polarization that was stated by the manufacturer...

[drlava]

In general this would be right, but you have to take into account reflection losses.

To really get the ratio, measure both max. and min. transmission levels (orthogonal polarisation angles) through the PBS.

[kaz]

The other thing to take into consideration is the cube itself like all mass produces optics and components things can go wrong with the coatings, Like Dave, I had a similar problem with combining a couple of reds, I purchased a cube off the doctor a while back and the problem was almost eliminated straight away,