Any known greens with Really GREAT divergence?

I am sorry if this had been posted somewhere, but I couldn't find anything....

I HAD two green lasers. The weak one (which I broke), bought online had great divergence, and would seem to out point my more powerful green laser.
My more powerful one, was a custom build. It is about 150mW and is way brighter and more visible than my weaker one was. But its divergence is pretty lacking.
I used pseudonomen137's mRad Calculator to give me a good estimate of the divergence....

What I ended up with is 2.59 mRad. (which is pretty horrible)
Long story short, I am looking for a green laser or module (doesn't have to be really high powered) that has a great divergence.
Does anyone know of any green lasers or modules with really good divergence, regardless of the power?

I like to use my lasers for long distance pointing.... Seeing if I can hit tree tops waaaay off in the horizon and stuff.

Thanks a lot


UPDATE:
Here is a couple pics to show how bad the divergence is.

I was pointing at a tree top that is only a block away. And the dot is roughly 3 feet round..... :banghead:



And zoomed in....

I suggest a beam expander, you can make a crude one with camera optics and such.

Companies known for great divergence are CNI (Dragonlasers, Laserglow, Novalasers), Optotronics, and as long as you're talking portables, My Skylasers 200mW, when focused to infinity, gets a .88 mRad.

Woodofcville said:

Companies known for great divergence are CNI (Dragonlasers, Laserglow, Novalasers), Optotronics, and as long as you're talking portables, My Skylasers 200mW, when focused to infinity, gets a .88 mRad.

Click to expand...

Thats really nice...
Wish mine had divergence like that. This module has crap focus.

I wish I could get a CNI or skylasers. If only they weren't so expensive.

Pontiacg5,
I have no idea how to even start making a beam expander. But I would love to have one....

The only problem is finding or building one that would work with my host.... :thinking:

Perhaps you can build a "beam expander" into the existing module.
I've done it a long time ago with a CNI module (X105). I was a laser modding/building noob back then.
Here is the old as hell thread: http://laserpointerforums.com/f49/cni-pen-improved-divergence-34095.html

Basically all it took was expanding the beam some more using a plano-concave lens and then adjusting the collimating lens for best divergence.

What module is used in your laser?

A beam expander is just a magnifying assembly that focuses.

So it could be as simple as two lenses. I am currently developing a beam expander that I will be producing soon and selling here at the forum with different end caps to fit different laser models.

You can use any optical magnifier for a crude beam expander, and it is pretty neat to try just so you can see the effect.

Take a small 10X pair of binoculars and shine your green laser through the eyepiece. It will cut the power down by maybe 60%, but you still get a very tiny expanded dot. A proper expander would minimize lenses to lessen power loss, and have anti-reflective coatings as well.

What I do is take a pair of binoculars, and I hold my Aries in the right hand and up to the right side eyepiece, while looking through the left side eyepiece with my right eye. That way, I can see the dot through the pair of binocs while it is being expanded. I can see the dot hitting things at over 2 miles away while doing this.

RA_pierce,
It is a module from LPF member NexBox. The module isn't bad. The only problem that I have with the module is the divergence. It burns very nicely and is crazy bright.... but I don't do as much burning as I do long distance pointing.

Seems like I might have to try making some type of beam expander.

Because this 2.59 mRad is just horrible, and I can't afford a CNI or equivalent laser right now.
I am pretty sure the the divergence on this, is worse than the divergence on my 445nm. But the green is so much brighter that it is still more visible at farther distances.

For starters, where would I get the optics/lenses?
I have a few AiXiz lens not being used, but I don't know if those will do anything.

Exerd,
Thanks for the help. I will for sure try the binoculars as a test.

Thanks a lot

I had one of those modules from Nexbox. Non of them seemed to be adjusted for divergence properly.

You need to break the glue on the lens thread and simply adjust the front lens yourself. It will have way better divergence when done!

The module I bought from nexbox died in about 30 seconds of use, so I took it apart to see what was inside. I found out that it is the same module that O-Like uses, driver and all, but the O-Like modules have bigger and more efficient crystals. So maybe they are handpicked better at O-Like.

Let us know how it goes once you adjust the lens.

Exerd said:

A beam expander is just a magnifying assembly that focuses.

So it could be as simple as two lenses. I am currently developing a beam expander that I will be producing soon and selling here at the forum with different end caps to fit different laser models.

Click to expand...

I'll be interested in seeing what you produce for sale

A useful app Optical calculations from LightMachinery > Thin Lens Gaussian Beam Program
gausian beam rev 2.0.xls
Be sure to use Internet explorer to see the graphical presentation for your results.

Exerd said:

I had one of those modules from Nexbox. Non of them seemed to be adjusted for divergence properly.

You need to break the glue on the lens thread and simply adjust the front lens yourself. It will have way better divergence when done!

The module I bought from nexbox died in about 30 seconds of use, so I took it apart to see what was inside. I found out that it is the same module that O-Like uses, driver and all, but the O-Like modules have bigger and more efficient crystals. So maybe they are handpicked better at O-Like.

Let us know how it goes once you adjust the lens.

Click to expand...

Yea, I know.

When I received the module, the lens was glued in place, and at a horrible focus point. I had a dead o-like module, and I just replaced the whole barrel/lens with the o-like module barrel/lens instead of dealing with the glue.

Then I focused the lens as best as I could. But I can't get it focused any better than 2.59 mRad

I too noticed that the modules look identical to o-likes modules. But one difference that I noticed.... Nexbox's have reverse polarity protection and o-like don't. (thats how I killed my o-like module, I accidentally put the battery in backwards). But the o-like had a much better focus/divergence.

I have had this module for a few months, I use it quite a bit and its still going strong. knock on wood. Hopefully it doesn't fail.

Is there any place that I can get the optics to make a beam expander?

I don't have any digital cameras that I can destroy.

I use one of those cheap roof prism binocs like bushnell 10X25. Disassembled it into 2 tubes then I took the lenses off to get the prisms out( less glass surfaces for losses).

I then reassembled the one tube and with aid of a telescope made slight adjustments to the objective tube till the dot was smallest on a cell tower a mile away and duct taped it in place.

I then used pipe insulation foam taped to the end where the laser goes so it slips in and doesnt move much.

There are only 2 lenses, both of which are coated, so losses arent terrible and end up putting a dot roughly 5 or 6 inches wide onto a cell tower a mile away.

Dot that size i cant even see it with naked eye very well. Cheap mans beam expander looks ugly but works.

herektir said:

I use one of those cheap roof prism binocs like bushnell 10X25. Disassembled it into 2 tubes then I took the lenses off to get the prisms out( less glass surfaces for losses).

I then reassembled the one tube and with aid of a telescope made slight adjustments to the objective tube till the dot was smallest on a cell tower a mile away and duct taped it in place.

I then used pipe insulation foam taped to the end where the laser goes so it slips in and doesnt move much.

There are only 2 lenses, both of which are coated, so losses arent terrible and end up putting a dot roughly 5 or 6 inches wide onto a cell tower a mile away.

Dot that size i cant even see it with naked eye very well. Cheap mans beam expander looks ugly but works.

Click to expand...

Yea that would be perfect. I don't care how ugly the beam expander works, as long as it helps.

If I could get one that I can take off when I don't need it.... that would be even better.

If only I could actually build one. :undecided:

EDIT:
I added pics to the original post showing how bad it really is.

The easiest way would be to find a internally threaded tube with threaded bulkheads. All you would need to do would be to epoxy a lens on each bulkhead, and then you could thread them for perfect focus. You could then machine an adapter from solid PVC rod, which is very cheap stuff. You would buy the rod oversize, then drill one end out to fit the threaded tube, and drill the other end the same size as the laser body.

Pretty simple

The laser slips into and out of the pipe insulation with relative ease but cant just fall out. A snug fit is all that is needed