
Originally Posted by
-bart-
If two beams combined with a pbs are not perfectly overlaping, the power-density of the beam is not doubled.
You are in fact laying beams next to each-other, like knife edging, doubling output power but preserving power-density, doubling beam area.
Combining beams in a way that doubles the power-density both in the near and far field is a though job. With two gaussian1/e2 1mm beams, you'll need at least 100µ position accuracy or better in the near field. The naked eye is not suitable for this job.
Use a diverging lens right after the pbs to make proper alignment possible.