473nm lab pictures

[GBD]

Bought one of these "de-functional" units from Ebay a while ago, and it showed up today. (So for the price of it, can't really complain)

The original problem was a spray like emission, there wasn't much of a dot, just a cool looking mess of light:


Luckly for me, the fix was pretty simple, the main cause of this was some junk (that I had no luck removing) stuck on the IR filter (so thats gone and will be replaced), along with some dirt inside the OF, with a bit of re-aligning, it seemed to have a decent output. (still has a wing across the dot though, so Ill need to look at it later).

Dot is about 3X smaller then the camera picked it up, about 7mm wide at 20ft. needs some work as you see, as with a propper lens it should get it to a more respectable diameter at that distance.

The output of these lasers isn't collimated. much like any DPSS, the raw output of the crystals starts out with a thin beam, and quickly diverges.

So tommorow Ill finish it with a propper collimator (might put the OF back on for stability, with the OF, the power output is about 10mw, without it does 35mw average, with the highest 70mw. It does have a pretty weak beam, but still visable in full darkness... I think with the help of some fog it should get interesting.

For now, some meter shots and close ups on the head itself:

The max it ever peaked:


The head with the cover off:


The crystal housing, OC just glued to the front:


Right before the prisms to correct the pump:


temporarly removed a plastic shield to expose the pump itself:


More to come tomorow, when I finish up and do some beamshots

 

[Wolfman29]

How did you take off the IR filter on yours? Mine was being a bit obnoxious too, and so I tried to take off the IR filter, but when I tried to remove it, I discovered it was attached by some wires that pass through holes in the IR filter plastic.

 

[GBD]

Can you take a picture? mine was just glued there and nothing else.

 

[Wolfman29]

Sure. I will show you the guts of mine.

Here it is:

You can't really see it, but that black line is a black wire that goes through a hole in the bottom of the IR filter into the thing to the left of it (my guess is to the TEC?). On the other side, there is a red wire that goes through a hole at the bottom, as well.

 

[GBD]

Well, thats odd, mine didn't have that (It was 4 wires total, 2 red/black for the TEC power, and then another pair, both gray/black (like yours) that are to a feedback sensor to regulate the TEC.)

So total in the front, you should have two (18 gauge?) wires in the front, with heatshrink insulation, those are connected to your TEC for the whole crystal housing.

On the side into the aluminum itself, a pair of thinner wires, probably a thermocouple or some other sensor to regulate the TEC at even tempertures. but that front plastic piece with the IR filter, wasn't there. it was just some piece of plastic to protect the guts. (no optics attached other then 2 metalic strips)

Also, in mine the IR filter isn't even inside the head, it was glued behind the OF, but infront of the housing, if you undo the 2 screws in the front that hold the front plate and OF in place, the IR filter should be exposed. (Don't touch the insides of the OF though)

 

[Wolfman29]

Oh. You know what? I don't think that IS the IR filter. I assumed it was because I thought I saw a window. But maybe not.

Mine is also a tad weak because the alignment of the hole through which the laser passes is a tid bit off (1mm or so) but it effects it. Anyway, I have been told that it isn't a good idea to take the front of the head off, to take away the OF? Is that true? I am a bit concerned that I will kill my head :\

 

[GBD]

It will probably reduce your life from more power (like running 445nm diodes at 1.8W-2W)
But instant death? no, that won't happen.

So yeah, removing the OF and the plate its mounted to, exposes the front of the housing, where a IR filter is just glued to the case. Removing it is very easy.

 

[jeffreythe00]

GBD I swear if you get ONE more laser like this... I will officially be moving to Canada! :beer:

Nice unit btw. Someone I know has about 30 of these units and the output is horrendous. Spray like scatter *yuck*. If most of these units are just dirty filters then maybe I will have to see about getting one

 

[Wolfman29]

But removing the IR filter means a crap ton of IR getting through =o

 

[benmwv]

Hey, I was thinking about buying one of these but now I'm confused. You keep talking about the "OF" and how removing that gets you more power but a shorter lifetime? What the heck is an OF? Output filter? Idk could someone just explain what it is/does?

 

[lazeerer]

Are those power Readings with IR since you said you removed the IR filter.?

If so i dont think there is much IR leaking through these units so that pretty awesome.

I have not taken my front off yet.

10mW is more then enough for me. When you add fog in the picture you will see that it really is bright enough.

 

[Wolfman29]

Yeah - I just want to get one of those lasers that has a decently visible beam in the dark, inside. And portable would be nice, too -.-

I plan on one day putting the whole assembly in a project box so the driver isn't just sitting there, exposed, but I just haven't gotten around to it.

EDIT: GBD, did you pot-mod yours at all? Or is yours just 37mW without the IR filter/OF without touching the driver?

 

[GBD]

Back from work, now to answer some questions in no particular order:

Wolfman:

I didn't modify the driver at all, this is only done to the head, that splatter was fixed by removing the IR filter (I didn't care much for it, so I destructivly removed it ) I have a spare PSU case from a different lab laser that I took apart to modify the PSU, so Ill end up puting this 473nm into it.

Benmwv:

The OF is Optical Feedback, which inside is consisted of some optics and a photodiode of some sort, most likly this laser is a pulsed system, and the OF is just to maintain a stable output optical power. natuarly this is ment to regulate the power output at a fixed value, so removing it pretty much lets the laser dump whatever it has to offer without regulatory feedback. So this could ultimatly shorten lifespan as the pump diode would be running at higher currents.

Hope that explains some stuff.

 

[benmwv]

Ahh ok so it's kind of like APC.

That helps alot, thanks. I'm pretty sure I'm gonna buy one of these or two, I need to use the housing and parts from it but I don't think I could tear it apart if I get a nice unit that is so simple to fix.

 

[Wolfman29]

I actually *did* modify the driver a bit. If you have V4 driver, it's pretty easy to change the current - just turn W2, which is the bottom level of the driver circuit. That pot directly controls driver current. But I am curious as to how you were getting 37mW BLUE output without modifying the driver - the driver is set to output slightly more than 10mW, and then the OF reduces it to exactly 10mW (which is only a theory, but makes sense). You sure that the extra 27mW or so isn't IR?

 

[GBD]

Yes, I got that extra power WITH the IR filter after I took the OF off, if you open the case, you will actually visaully see the whole system glow brighter as soon as the OF comes off.

That 30-35mw average was of 473nm only, as that was when the IR filter was installed. after removal, the power didn't change much exept I started to see it peak as much as 70mw at some points. but rest assured, you will get that increase of power just from removing the OF from the front of the head, without touching the driver.

I do have a pot on there, (labeled as you said)... but I think I will leave it alone.