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I need a lens or beam narrower? to make a beam tighter.

TheUniverseX

TheUniverseX

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I have a Rayfoss 500mw Green laser TORCH and the beam is quite thick when it comes out of the apperture which i expected when i bought it. I want to narrow the beam to make it tighter and more focused, is there an inexpensive lens or beam narrower? that i can affix to the apperture to do so? I dont know much about beam expanders or beam narrowers? I did a little research but then ended up deciding to ask about it here with people who are knowledgeable. Thanks in advance.
 





T

Things

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Unfortunately what you are trying to correct is a law of light physics. If you make the beam narrower, your divergence will increase significantly.

Unless you just want to focus it down to a single point for burning, there is not really any way to physically get the beam any smaller apart from beam masking.
 
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donprado

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Thats not easy! There are beam expanders, which make your beam wider, but give you better divergence. Probably you could use a beam expander in the other direction, BUT it will not be easy to attach it to the laser AND with narrowing the beam, you will automatically end up with a worse divergence!
I'm afraid, you will have to live with the wide beam! But hey - 500mW green should give great beamshots, even with a wider beam :evil:
 
TheUniverseX

TheUniverseX

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Thats kinda what i thought that it would be extremely difficult to do. I will have to stick with the wide beam on this laser torch i do love it anyway. And yes it does give amazing beamshots, thick beam like a lightsaber :takeit:
 
TheUniverseX

TheUniverseX

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Oh and one more question since it would be difficult to narrow the beam is there any inexpensive focusing lenses or devices i could affix to the aperture to just focus it into a small point since this laser torch does not have a focus? I want a focus on it because it takes a little longer to light a match seeing as the beam is so thick and the light energy is spread out and less into a single point because of the thick beam.
 
Bluefan

Bluefan

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Beam expanders give a thicker or thinner beam, but just a simple positive lens (for example a magnifying glass) will already focus the beam to a small spot.
 
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donprado

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You can use any convex lense. You get them for example at Optotronics: Lenses
The smaller the focal length, the smaller the point but the smaller the depth of focus (see Newport Gaussian Beam Tutorial).
I would recommend a focal length of about 10cm, which should give you a spot of aprximately 10 microns. Small enough for burning like hell :eg:


The most improtant: if you do burning, especially with additional optics you have to wear good savety goggles. Your eyes will say :thanks:
 
TheUniverseX

TheUniverseX

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Indeed safety first :) Ugh this site has a $20 minimum purchase :yabbmad: and all i need is a small focusing lens, any more suggestions for the best lens to do what im looking for? sites? Cant wait to get burning *pyro grin*
 
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anselm

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Every green module has an inbuilt beam expander: a set of one expanding lens directly
after the crystals, and one collimating lens, the one you can see from the outside.
On some modules you can remove both of these lenses, leaving nothing
but the bare crystals.
I'll spam this picture once more, because it's so helpful visualizing!
glpmca1.gif

Picture shamelessly stolen from Sam Goldwasser's awesome LASER Repair FAQ.

The beam exiting the crystal is very thin, and consequently has very nasty divergence,
maybe some 10cm dot 2 meters away!

I'll admit I've only found this to be easily done on one of my green modules,
the expanding lens is often glued in place, and I wouldn't want to break the glue and mess with it.
 
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LSRFAQ

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Would you mind giving Dr Sam credit for the pic please? He goes nuclear sometimes when he sees that one used without credit. As in DMCA takedown nuclear...

Thanks, Steve
 
daguin

daguin

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LSRFAQ said:
Would you mind giving Dr Sam credit for the pic please? He goes nuclear sometimes when he sees that one used without credit. As in DMCA takedown nuclear...

Thanks, Steve
Click to expand...

Hmmmm. Maybe it needs a watermark. This is an ongoing issue once a picture has made it into the "wild."

That being said, anselm, you should edit in at least an attribution. If you can, it would be even better to include the URL.

Peace,
dave
 
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anselm

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Sorry about that, I tend to show this particular diagram a lot to people to help them
visualize how a DPSS works.
Sometimes I even forget it's from Sam's page originally. It's the 1st thing that pops
up when you "google image" for "DPSS".
I edited in the source with a link, an I'll remember for the future.:whistle:

The watermark would indeed be a good idea, its what everybody who doesn't want
their pictures all over the web without due credits does.
 
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steve001

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Use Without Permission or Acknowledgement Alerts
While I am flattered when other people are interested in what I've developed, everything in Sam's Laser FAQ is copyrighted material. This includes, but may not be limited to: all text, photos, diagrams, and schematics, as well as the look and feel. Obfuscation of the material by removing or adding to it, changing colors, etc., does not make it acceptable! The laser community is rather small so violations will very likely be uncovered. If you're using Sam's Laser FAQ material on a public Web site or in an eBay auction, I will find it. As noted in the section above, non-commercial use of this material is permitted as long as the source is acknowledged in an appropriate manner. So, why take a chance at ending up in this hall of shame for the World to see! :) However, for-profit use is strictly prohibited without prior approval. Sam's Laser FAQ - Preface, Introduction, What is a Laser?, Safety
Click to expand...

Let's not see the name of this site listed on Sams Laser FAQ and bring shame upon us
 
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