Is my laser dead or...?

I have a green laser that I got a while ago that has stopped working. so I decided to take it apart to see what was wrong. I carefully broke it down and tried to get it to work. It turns out it was just some cheap china solder that broke, so I fixed that and tested it... WTF it is red, and why is it so dim?! I hopped on the computer and found out that it was actually IR, and that can happen when something is broken in the laser. So I sadly put it back together and shelfed it. But then I was looking on this site and saw a diagram showing that the diode itself is IR and that funky prism thing in there was "turning it green".

So it should work assembled, right? Well, it still doesn't. Using a digital camera I verified that the light is still coming out very dimly IR, you have to look down the tube to see it with the camera, it won't shine out.

So did I assemble it wrong? Is there something that needs adjusting? Is it just plain broken?

One more thing. farther up on the assembly, where the prism looking thing is, there is what looks like a photoreceptor with two wires that lead back to the driver board. What is this, and what does it do?

Thanks.

Ok first of all DO NOT LOOK AT THE IR DOT, BEAM OR DOWN THE TUBE!!! it is extremely dangerous... you see it as dim red because the IR is very close to the red wavelength... secondly im not sure what you mean by funky looking prism... but I'm guessing your talking about the crystal.. this crystal changes the IR beam from the diode to a green beam... this is probably your problem.. you have either broken or dislodged this crystal.. if so you probably need to buy a new one! next the photorecptor is most probably the IR diode... if you can see that you most probably recked the assembly or easly dislodged everything inside!

Please post some pics so i can be 100% sure of what your problem is!

Hope I helped! -Adrian

Yeah, don't worry, I only saw the dim red when I had the diode by itself without any focusing, then I decided it would be best to view it through a camera. I can still see, so I HOPE I won't go blind x_x...

I don't have any pictures ATM, but I'll describe it as best I can.

The IR diode itself has three prongs and is soldered onto the driver board edge with one prong on one side and the other two on the opposite side. The diode is then screwed into another assembly that most likely contains the crystal. At the top of this assembly there is what I called the prism. It is a piece if transparent material with a blue-ish green tint under normal light. This piece is angles at about 45*, and behind it is the photoreceptor(?) mounted perpandicular to the axis of the laser. I am assuming that the piece of material is angled to direct some of the beam towards the photoreceptor.

I do not believe that I have dislodged any of the crystals because they are in this separate assembly, and all seem to be in place. I have a feeling it may be the diode itself, that it may have had it's wavelength altered slightly so it won't work with the crystal. If the diode is shining IR light in the proper wavelength, it should be coming out green from the other side of the crystal assembly, correct? Is there any kind of focusing that needs to be done between the diode and the crystal?

This may be more trouble than it is worth, but I spend $120 on this dumb thing back in the day, and I'd like for it not to be permanently broken... At the very least I can gain knowledge on these green lasers from this discussion.

Thanks again.

1. yes if it is outputing the proper wavelength it should be making a green beam (assuming everything else is placed right and working)
2. no there is no way as far as i know of focusing the diode and crystal
3. I'm not 100% sure of the assembly of this laser but I would guess that could be the IR filter which filters out the infared rays and only allows the green wavelength through.
4. What output power is this laser?

Btw this is what you are talking about right??



or is it the one below?



Can you please explain where in this assembly u think the problem lies? if you want you can save the image and put a circle around the area in question!

I still recommend you buy a new module but if you insist that you are able to fix it i might be able to help you out..

Hope that helped -Adrian

There is no such crystal that converts IR to green. The IR is there to PUMP the crystal, and it's the crystal itself actually lasing, thus why it's called diode PUMPED solid state.

Chances are you have killed the IR diode (most likely), or killed the crystals.

If it's the diode thats dead, then it can be repaired, if the crystals are dead, then you may aswell just replace the whole laser.

You could get a Green module from... O-Like... here...

www.0-like.com--product

It would probably be the least expensive way to fix your laser...


Jerry

things said:

There is no such crystal that converts IR to green. The IR is there to PUMP the crystal, and it's the crystal itself actually lasing, thus why it's called diode PUMPED solid state.

Chances are you have killed the IR diode (most likely), or killed the crystals.

If it's the diode thats dead, then it can be repaired, if the crystals are dead, then you may aswell just replace the whole laser.

Click to expand...

Really.. I always thought the beam of IR passes through the crystal, excite them then releases a beam of green and that pasted through some sort of lens assembly to get it into a uniform pattern...

You learn something new every day!

Thank you -Adrian

that red thing.. meaning the CRYSTAL is already dead. hehehe get a new module... go o-like.com

Thanks for the help everyone!

The whole setup I have here looks just like the top one you posted(the one from o-like), but it is slightly different. I'll try and get some pictures today.

I agree the simplest thing would be to replace it, right now I'm just learning :yh:

There definitely is such a thing as a crystal that converts IR to green, and there are actually two crystals in that module. They are sandwiched together into a tiny module called a DPM.. What happens is the 808nm diode's output gets focused on to a crystal which turns its output into 1064nm light. Still in the IR, only farther out. Then this output is fed through another crystal that converts (frequency-doubles) the 1064nm IR into 532nm green.

808nm near IR => 1064nm IR => 532nm green


I would suspect that since there is absolutely no green coming out of there even when the crystals are positioned correctly, the crystals might be in backwards. They will only work if the pump light enters from the rear, so you could try flipping the crystal assembly around.

It's good to try this stuff for experimentation, and to learn about how these things work, but in the case of most pointer modules you won't get a truly useful output by trying to repair them yourself. Alignment can be pretty tough, so you'll likely get a lot of flickering and mode-hopping when you finally get some output.

If you just want to make your pointer work again, buy a new module from o-like.

Thanks,
I don't thing the crystals are in backwards... I don't think I can even remove them.

What do you think about the laser diode pumping the wrong frequency. Maybe it got dropped, or over heated from the soldering iron? Maybe it got hit with too much voltage or current? I was testing it with out power supply set at 3.0v (the output of the batteries normally) I didn't realize that wasn't such a good idea until I started reading here. I'm not really sure what it takes to get one of these things off. It was sitting on my desk for a while and people like to fiddle with it so it may have been dropped.

How far did you disassembe the module?

If the crystals and their mount haven't been moved of removed, then most likely the diode has rotated in it's housing, causing it the whole thing to go out of alignment. You could try rotating it. The diode is retained by a tiny brass ring. If you loosen the ring it should allow the diode to be rotated.

I will try that. it is in a brass ring and I may have not gotten it oriented properly when I put it back in.

ElektroFreak said:

There definitely is such a thing as a crystal that converts IR to green, and there are actually two crystals in that module. They are sandwiched together into a tiny module called a DPM.. What happens is the 808nm diode's output gets focused on to a crystal which turns its output into 1064nm light. Still in the IR, only farther out. Then this output is fed through another crystal that converts (frequency-doubles) the 1064nm IR into 532nm green.

808nm near IR => 1064nm IR => 532nm green

Click to expand...

There you go I thought I read that some where.. I guess its not standard in all modules then.. thanks for clearing that up ElectroFreak