help with optics

[b52productions]

im not the best with optics so i hope someone can help me out.

i have seen builds where people use the diode sleds to combine colors but i would imagine there is a great loss since the pbs is only 3~4mm. The beamprofile itself is approx 6mm.

so i would like to do this in a slightly different manner. i would like to focus the aixiz module to a point approx 1.25 in from the aperture and within this focal point introduce some collimation optics to better fit the beam through this aperture.

my reason is for project below:


i have seen this done without the colimating lense but that requires expensice pbs cubes something i just cant afford. So i dont see why we cant make use of the already surplus optics.

anyhelp in my endevor is greatly appreciated.

Great forum by the way. I am a noob so pardon my misakes lol.

[sbk]

Hi,

First, you can only use ONE PBS cube to combine diode's beams.
Since the diode's beam is polarized, and the cube reflects the horizontal polarized beam and transmit the vertical one, you have to place one diode vertically and the other horizontaly. This means that after the cube, you have both horizontal and vertical polarized beams, so you cannot combine any more using another cube... I hope it was clear enough

Here's a picture of the principle of a PBS cube :

You have other methods to combine more that two beams, like mirrors knife edging. And the PBS cubes are usually bigger than 3-4mm. Mine is 10x10mm for example.

And that people usually do to reduce the beam size, is placing a lens system, but after the beams were combined.

[mixedgas]

What he saw was probably a Arctos style design, and perhaps he has PBS confused with Knife edged mirrors.

Steve

[buffo]

What he saw was probably a Arctos style design, and perhaps he has PBS confused with Knife edged mirrors.

Exactly. The Acrtos design uses a large mirror mount that looks a lot like a cube. But yeah, it's just a mirror, and they're using the same knife-edge mirror trick that we've discussed before.

b52productions: Do a search here on PL for "Knife mirror" and you'll get plenty of ideas.

Adam

[b52productions]

AHHHH something new to learn Knife edge hmmmm...thanks for the input !!!

[FourDee]

I find that name somewhat funny as it implies that you need very thin mirrors, but in fact the thickness of your mirrors doesn't matter

[Laserman532]

well I would say thickness of mirror does count because if the back of the mirror is beveled away from the coating you can get your beams closer together. IMHO

[mixedgas]

I find that name somewhat funny as it implies that you need very thin mirrors, but in fact the thickness of your mirrors doesn't matter

but if you can polish off the edge of the mirror, it does help considerably in aligning them.

Steve

[b52productions]

can some one point me to a good post on that subject as i couldnt find one.

[buffo]

can some one point me to a good post on that subject as i couldnt find one.

Here are a few you might find useful:

One from me that explains the basics

Phritzler's massive 24-diode red project

Andy Con explains how hard it is to align the mirrors to pull off the "knife edge" trick

Good thread explaining the difference between PBS cubes and mounts. Note the picture of an Arctos projector mentioned above in the 8th post. (the square mirror mounts look like cubes, but they're not)

Adam