I got my first Green Laser 532nm today !

[Accutronitis]

So far it's just a green dot on the wall but it should be pretty cool at night !

I have just a few thoughts, During my searching and reading up on lasers I have read many time about how some lasers use crystals to achieve their color, And sometimes a dif type of crystal for a dif color.

Now having read that it should have came as no surprise that when I dug into it to straighten out the beam a bit and at the same time see what make it tick I realized that the beam has to go through the crystal it's self......

The crystal is down underneath the part holding the lens and must be align just right for the beam to turn green.....

 

[RedCowboy]

The driver powers an 808nm pump diode that can have it's own lens or not, but it pumps a 2 part krystal that's bonded of neodymium doped YV04 and KTP to convert 808 to 1064 then double the frequency to 532nm, there is a mirror coating that passes best 1 way at the input and the output has the OC or output coupler which is a mirrored coating with a tiny hole in the center, these mirrors are typically coated onto the crystal pair in this case, understand that if you pop off that brass ring that has the crystal glued in you will be looking into invisible 808 that's typically 5X the power of the laser, so don't look into it.

Interesting thing you have no doubt seen is the BE built into the output end, it has a double concave sometimes refered to as a gradient index lens and a final focus lens because the output from the crystal is needle thin but it diverges faster, so they use a BE.

The older ones were set up for a nice infinity beam, the newer ones to burn a dam match so I replace a lot of my final focus lenses, sometimes with a bigger lens at a longer FL in a sliding cardstock tube.

You can take the crystal off and refocus the lens to project 808 onto your wall that you can see with CCD cameras such as security or old cell phones, many new cameras and cell cams have an IR blocking filter.

Here's a couple pics so you don't have to pop yours off to see, I have a bunch of crystals somewhere, they are tiny and bonded from the 2 parts with mirrored coatings on the ends.

You can see how cheaply made these are, overheating the glue or shock can throw them out of alignment.

I have some that have a separate crystal setup and some that use a C-mount diode in the back, those are rare.

This one has a lens for the 808

I know this stuff has been posted before and we are kinda wasting bandwidth, but it's cool to see the work that goes into these and the evolution of designs.

 

[diachi]

Damn, those crystals are all yours RCB? You've got quite the collection!

Think you covered the basics of how these work pretty well!

 

[RedCowboy]

I have a lot more, but they used to fail a lot more easily.

What I really want are some 1/2 watt to 1 watt 532 modules, and a 10 watt lab would be cool, I have some of the medium housings that put out 30-40mw, but what am I going to do with them now, I don't think I could just put in a bigger C-mount pump, it would burn the crystal.

5W C-mounts are getting cheap, I could get some new lenses and make IR units.

This should fit it but I wonder how good the beam quality would be, it has a micro lens no doubt for axis correction. It says 8/1.5
http://www.ebay.com/itm/808nm-10W-C...hash=item3a75f6603b:m:mWxJJhJUIgHQbdrQQV-3xBA

 

[diachi]

I have a lot more, but they used to fail a lot more easily.

What I really want are some 1/2 watt to 1 watt 532 modules, and a 10 watt lab would be cool, I have some of the medium housings that put out 30-40mw, but what am I going to do with them now, I don't think I could just put in a bigger C-mount pump, it would burn the crystal.

5W C-mounts are getting cheap, I could get some new lenses and make IR units.

This should fit it but I wonder how good the beam quality would be, it has a micro lens no doubt for axis correction. It says 8/1.5
808nm 10W C-Mount Laser Diode with Micro-lens | eBay

That's true, even the cheap ones tend to last a while now.

Up at those powers design gets more complicated, definitely need bigger crystals to start off!

Yep, that's a FAC lens on there, should improve the output beam a good chunk! Still going to be nasty, but better than just raw.

 

[Accutronitis]

I know this stuff has been posted before and we are kinda wasting bandwidth, but it's cool to see the work that goes into these and the evolution of designs.[/QUOTE]

If you had never reposted this I would more than likely have never seen this SO I thank you !

 

[paul1598419]

I was surprised to see they want $10.00 shipping from NJ.

 

[Gordon Shumway]

Congrats, I remember my first 532nm green pointer, it was back in 2003 and it was a custom build, 50 mW of power and cost $550. How far we have come. I was mesmerized by the lime green beam. I also had a cryonics 75mw cylindrical multi-line, I was in love��. The 515nm line captured me. I currently have a eghemus 515nm custom built and am quite happy with it. It looks like a weathered lightsaber. Again, having a new laser is an amazing feeling, may it serve you for many years!!!!

 

[Accutronitis]

This laser seems to have very, very, low divergence ?

I shot it across the lake (aprox 800m) last night and the dot was very small, Smaller than I thought it would be ?

 

[Alaskan]

Measure the dot size at 1 foot and at 25 feet and let's calculate the divergence. You can measure it at any distance, not just 25 feet, but the further the more accurate.

 

[CurtisOliver]

Yes what Alaskan said.

With green DPSS's you could be seeing anything from 0.8-1.2mRad. They usually have very good divergence.

 

[paul1598419]

This laser seems to have very, very, low divergence ?

I shot it across the lake (aprox 800m) last night and the dot was very small, Smaller than I thought it would be ?

If you are just looking at the dot from where you are shooting the beam from, the dot will always look the same size as it is farther away and the distance makes it look smaller than it actually is. Look at a paper plate at 800 meters and see how small it looks. You need someone else to be at the spot to measure the diameter. Then you will know exactly how good the divergence is.

 

[diachi]

If you are just looking at the dot from where you are shooting the beam from, the dot will always look the same size as it is farther away and the distance makes it look smaller than it actually is. Look at a paper plate at 800 meters and see how small it looks. You need someone else to be at the spot to measure the diameter. Then you will know exactly how good the divergence is.

Yep, unless you've got a target with a meter stick or something on it and a pair of binoculars to look at the dot at said target.

It's difficult to judge divergence with any accuracy just by looking at the dot from a distance, at least with lower divergence lasers. You can compare lasers, you can see that some are objectively terrible, but extracting any sort of numerical value out of that requires actual measurements.

 

[Accutronitis]

I'm sure you are both right, I need to do some tests with my buddy "PJ", I guess I'm use to the divergence monster the 44 so it seem really small but there is only one way to know for sure.......