Can you use a dichro to join two red beams or does it have to be a beam splitter??
Can you use a dichro to join two red beams or does it have to be a beam splitter??
Eat Sleep Lase Repeat
Andy;
You need to use a polarizing beam-splitting cube to combine two red beams of the same wavelength. You also need to be sure both red lasers are outputing a polarized beam (some are randomly polarized), and finally you need to be certain the polarization angles are both 90 degrees to one another.
A dichro will only work when you're trying to mix *different* wavelengths. For example, you could use a dichro to mix a 660 nm beam with a 635 nm beam.
But if you want to mix two 660 nm beams (or two 635 nm beams for that matter), you need to use the polarizing beam splitting cube.
Adam
There is *one* other alternative, but it's messy...
You can try to bring the two beams as close together as possible using a first-surface mirror placed very carefully so that it reflects one beam while letting the other one shoot past it.
Have a look at what Marconi is doing here in this post for an idea as to what I'm talking about. Note that this isn't perfect. You will always have two separate beams when you do this, but if you get the alignment really close, you might not notice it when the beam(s) are scanning around. (Think of it like a TEM01 laser!)
Adam