How much of a laser beam can you fit onto the galvo mirrors?

[MisterWilling]

I tried to get this question answered in another thread but it kept getting skipped because my other questions we answered instead.

I need to know what size I need to get my laser beam down to. This is so that I can fit all (or most) of it onto the mirrors. I plan on building a knife edge array and so far it doesn't look I can do it with the lenses I have. I may need to shrink the beams down more after the knifed edging with a lens.

I would guess if the mirror is at a near 45° angle that I would just use trig and that would show me how much. On my 5mm mirrors I could fit 3.5mm of laser. Please let me know if I am approaching this the wrong way.

I have included a crude paint drawing to further illustrate what I mean.

[allthatwhichis]

I got nothing personaly, but check this thread out; I wouldn't exactly call it a start as more of a goal.

http://www.photonlexicon.com/forums/...3519#post33519

[tocket]

You can calculate it with trigonometry. When the galvos are in their resting position they are at a 45° angle. That means a 5 cos 45° = 3.54 mm wide beam fits the mirrors. It's probably more useful to know the width at the maximum scan angle though. It can be calculated as:

Mirror width * cos (45° + scan angle/4)

[MisterWilling]

Excellent, thanks for confirming that.

With my current lenses I get a 4mmx2mm beam. Looks like I'm going to need to shrink them down after knife edging 4 diodes because the beam will be huge.