0.32 mRad DPSS 532nm green!

[crazyhobo]

This defies all that I've ever seen. I glued a second expanding lens in my "Cyber" 532 100mw green laser to reduce divergence. I did this 2 years ago to another laser (http://laserpointerforums.com/f42/lazerer-classic-150-divergence-cut-half-69924.html) but I had even better results this time. Check out that thread for instruction on how to do this.

At aperture, the beam diameter is 3mm, or about 1/8".
At 230 feet, the beam diameter is ONE INCH.

That's 0.32 mRad ya'll.

I don't have an LPM, but it still burns like crazy when focused to a point. I imagine there are some considerable losses with the light passing through a second PLASTIC expanding lens. It's worth it to me to have this ridiculously low divergence though.

Picture descriptions:

1. SCARY IR (I swapped out the crystals while I was in there.)
2. Dual expanders!
3. The spot without the collimating lens.
4. I was shining it on that white fence.
5. View from the fence.
6. The spot at 230 feet.
7. Cell phone beam shot without fog.

Note that this only works with focusable lasers, as it increases the distance needed between the expanding lens(es) and the collimating lens. With this laser the point at which it is focused to infinity is now when the head is about 1/3 of the way unscrewed.

 

[hwang21]

Impressive :drool:

 

[NO4H99]

Very nice, I have to do this with one of mine now. thanks :beer:

EDIT: Must spread it around.

 

[kaunak]

That is very impressive, esp comparing to the multimode diodes today. I still have an old sl1236 that can get a similar divergence when focused. ie .3mrad at 24meters

Zraffle: correct, but I was *mostly* referring to a diode/single lens setup. I'm going to see what kind of numbers I can get at 24m and prime focus using just a 3 element tomorrow

 

[ZRaffleticket]

Not really impressive in response to the multimode diode comment.

As long as the IR spot gets focused correctly into the crystals, the conversion process more or less corrects the multimode specs.

___

Regarding the divergence itself: Holy crap that is awesome.

 

[steve001]

This defies all that I've ever seen. I glued a second expanding lens in my "Cyber" 532 100mw green laser to reduce divergence. I did this 2 years ago to another laser (http://laserpointerforums.com/f42/lazerer-classic-150-divergence-cut-half-69924.html) but I had even better results this time. Check out that thread for instruction on how to do this.

At aperture, the beam diameter is 3mm, or about 1/8".
At 230 feet, the beam diameter is ONE INCH.

That's 0.32 mRad ya'll.

I don't have an LPM, but it still burns like crazy when focused to a point. I imagine there are some considerable losses with the light passing through a second PLASTIC expanding lens. It's worth it to me to have this ridiculously low divergence though.

Picture descriptions:

1. SCARY IR (I swapped out the crystals while I was in there.)
2. Dual expanders!
3. The spot without the collimating lens.
4. I was shining it on that white fence.
5. View from the fence.
6. The spot at 230 feet.
7. Cell phone beam shot without fog.

Note that this only works with focusable lasers, as it increases the distance needed between the expanding lens(es) and the collimating lens. With this laser the point at which it is focused to infinity is now when the head is about 1/3 of the way unscrewed.

Amaze yourself some more by swapping out the collimating lens, that's the lens the beam passes through as it exits the laser with a longer focal length one. Make sure it's has a wider diameter so you catch all of the beam. Use a plano-convex, they have one flat side making them easier to mount. If you don't know what 0.32mrd actually means it means the beam is expanding 0.32 millimeters per meter once it is beyond the Rayleigh length. Rayleigh length is where the beam only expands the square root of 2 or 1.4 times its diameter starting at the lens surface, so your beam of 3mm will have a diameter at the maximum Rayleigh length of 4.2mm, beyond that distance the beam expands in a linear fashion like a flashlight beam does.
There's no limit to how low of a divergence one can get.

 

[crazyhobo]

Very nice, I have to do this with one of mine now. thanks :beer:

EDIT: Must spread it around.

Word up!

I wish there was a beam diameter / divergence option from the manufacturers.
I'd much rather have a 3mm beam that stayed tight than a 1.5mm one that didn't. And I don't think I am alone in that.

 

[Atomicrox]

Great work, I might try that in one of mine!