Changing green laser to an IR Laser

Ok so I have had a weapon mount cheap green laser for a little while.

Well I am into the whole NVG thing and I dont think anyone should pay $800 for an IR laser and not when I found out that there is more work to make a green one. Anyway, I pulled mine apart and pulled out the crystals. Worked great went back together. Slapped on my NVGs and the beam sucks. It looks like a little bubbly spot. I checked to make sure that the lense was back in and tried it with and without with no luck.

Any one that has done one of these before have any idea what the problem could be?

Oh and there is also this odd little thing inside the assymbly between the diode and the lense that looks like a little sensor of some sort with two wires connected to it. I moved it out of the way but it had a crystal over it when I removed the magic crystals.

What you have there sounds like uncolimated IR...it is unfocused, and will be VERY hard to focus now....

HMMMMM, I ordered a red one just like it from ebay. It is a G&P airsoft company. Anyway, I am thinking about just unscrewing the upper half above the diode on the red and attaching the IR one. Since the red one does not use crystals I am hoping this will fix the problem. Is there another way around doing this?

Trial and error with focusing IR unfortunately....sounds like you have a pretty good grip, though !

OK --- Sooooo -- Like you took out the crystals. The lens system was made to focus on the green portion of the laser assembly. You need to move the focusing lens closer to the source (LD). The RED LD mount might work. Remember that the faint dot is deceiving -- there's a bunch there -- be careful.

Mike

Nice idea... I think the dot should be VERY bright with night vision... but invisible without it! ;D

Here's a couple pointers... What power was the green? Remember that it takes a TON of IR to make a bit of green. So, for a 20mW green you're looking at about 100mW or more even. (fiures might be exaggerated, if pseudo passes by he'll post the right numbers ) So, the whole thing should look something like this... looking from the outside in, the collimator, then the IR filter, then the crystals, then the laser diode. The collimator would be as far away from the crystals as would be needed to get a correct collimation, and if you remove the crystals, the collimator should be that much closer to the source, which now becomes the LD. Is you can move the diode forward, or if you can move the lens back, you should have a working IR laser. This should also be doable with the red gun mount. There are a couple problems you might run into with the red laser mount though. IR collimation is very much not like red collimation, and IR beam specs are very sucky at best. Also, the drive circuit for a red diode might not be powerful enough to get the IR diode to lase, and you would have a hard time trying to get the this to even light up, let alone lase. This should be a very interesting mod if you can actually get it working, and please post pictures and update us on your findings. But also be very careful using such a laser for aiming as if it is in fact that powerful you really do not want it to be shining into people's eyes. That would be very bad... :-?

GL;
DDL

Well I am on the right track. I found an old pointer and tried the plastic lense out of there. It made a much nicer dot. Nothing intense but good enough to spot at a distance with super night shot on my cameral. I am having a small electrical problem with the unit that I have had since I got it which prevents it from always working. When I get the red one I will try that lense and replace the presure switch.

another thing to keep in mind is that diodes emit a line rather than a dot. it can look a little wierd with the wrong optics.

i have tried this, and mine burnt stuff, but focusing is very hard, since the output can be lined, not a dot. maybe you could put it back together, but disaline the crystal a little bit, so it doesn't make green?

things said:

i have tried this, and mine burnt stuff, but focusing is very hard, since the output can be lined, not a dot. maybe you could put it back together, but disaline the crystal a little bit, so it doesn't make green?

Click to expand...

that won't work at all.

you COULD split the crystal in half and remove just the KTP portion and keep the ND:YVO4 then you'd have a 1064 laser, proably 80-90% the power pf the raw pump diode and it would be tem00 ( a dot ).

That's a pretty cool idea! I'm not sure about the visibility of such a beam in NVG though... :-/

--DDL

most ccd based nvg are sensitive to 900-1300nm. should show up fine.