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Newbe needs help. (laser "spotlight")

Toad

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I've been surfing the posts all around this forum and candlepower trying to find some info so now I'm left to ask.

I need to enlarge the footprint of lasers to act as a spotlight, so distance is not what I need I'm shooting for coverage.How are some ways that one might go about this safely?
I'm assuming a convex lens will spread my beam out a bit but will the turning mirrors have a big effect on the footprint outcome?

Any help will be awesome and due recognition will come to those willing to help me.
 





Blord

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If the laser is focusable then just turn the focus knob until you get a large dot/footprint.
The laser light will be spread over a larger area so that the power density of the beam is very low. The dot/footprint is harmless.
I still don't advise to look into the laser light.
 

Toad

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I have no full laser(s) to speak of yet, just diodes and heat sinks and power supplies, I'm trying to see what I will need to get in the name of mirrors and lenses. I'm building what I will refer to as a Laser Spotlight Grid one convergence of RGB and three small red and blue sites, and one UV site. Trying to max the footprint to at least one sq foot.
Safety will be a big concern for this build seeing as it will be used in confined space.
 
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First off: Hey Duke, big congrats on 1K posts!!

Toad: It would be massively helpful for you to give some specific information regarding your actual intended application. At the very least, you should provide your intended range (distance) over which you'd like to throw that spot.

And, as TheDukeAnumber1 indicated, we need to know whether you want a low-divergence beam of a given diameter, OR a rapidly diverging "cone" of light. The optics required for achieving each of these goals are very different.
 

Toad

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:oops: Okay, first the application is lighting. Sounds excessive but we have our reasons.
So to elaborate I will need to have the unit at least 6' from the ground and cover at least 2' x 2' to start.
we want to design on small scale and work up.
I know its a risky idea as far as visual safety(eyes in general)
but I'm willing to take that in trade for the hope it works.

I hope this helps to elaborate and really appreciate all the help/advice/info
 

norbyx

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From what I can understand you biggest concern is to keep the light confined to an area of 2' by 2' am I correct?
If you are looking for a white RGB type of light, than you might have a problem since the convergence of such lasers is not always good and you still can pickup some of the 3 colors separately in the edge of the spot.
 
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well i can use my 1.6 W blue laser and zoom it super close, ie the small point is like an inch from the laser front.. to where it will flood my whole yard with blue light so a general focus ring could work
 

Toad

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norbyx, thank you, I'm not too concerned about convergence being choppy as long as I cover all the colors(eventually I want to work in all visible color and a few uv) we want to hit really high on the CRI.
The light doesnt have to stay in the 2'x2' area , just a starting footprint as goal. The more coverage we can get from less power the better.

in the end we don't know if this will all work but...a Japanese company is doing some research on this same level so it cant all be just a shot in the dark.

Focus ring eh? Ill have to look into that Thanks!
 

Toad

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FYI, the lasers we are using are all "lab" lasers no pointers. We need long life on these diodes and the unit in general.
 
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Assuming you already have a collimation lens fitted
Just unfocus the laser .
It should work nicely as a short ranged spotlight.
However for illumination purposes , lasers can't really compete with non-coherent light sources.
 

Toad

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Sadly I get what your saying. But I'm still determined to follow through.
when we did our introductory experiment into this we setup a array of lasers and array of LED. We used nine 1w LED to light up a 6" x 12"x12" container and same with lasers but only six 3.5v 5mw lasers and a set of lenses from a few old Olympus cameras we got. At the time we only had a cheap light meter that only does foot-candles and lumen.(I KNOW NOT THE TOOL TO USE)
In the run we had a consistently higher lumen rate from the lasers over the LED.
Now I know lumen are really only for our eyes and a way to gauge light we see but that gave us some hope that we where in the right direction.
 
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Hey norbyx, I see that you recently passed the 1K post mark as well. Big congrats to you, too!

Back to Toad: Well, I think the advice you've received so far should take you in the right direction, with a bit of diligent research on your part for the details necessary to apply it to your situation. If your lab laser units lack the ability to de-focus their output, then you should obtain some very short focal length lenses (either positive or negative) to produce the divergence you require.

At the risk of sounding as though I'm talking "down" to you, I'd like to mention a few things: It's my understanding that a laser-based RGB "white light" system will only approximate white light, appearing white as interpreted by human vision. I mention this because you said that you "want to hit really high on the CRI". Now, I'm no expert in photography, repro-graphics, or professional video production, BUT I have had a bit of experience in machine vision and software-based image analysis. If your application requires a high CRI, such as that produced by tungsten or tri-phosphor fluorescent sources, then the narrow bandwidth components of a laser-based RGB system may not produce the results that you want. Additionally, I can tell you that many machine vision systems do not play well with laser illumination. This is because the nature of coherent light sources can result in undesired artifacts stemming from interference and diffraction effects. I realize that you haven't gone into that level of detail regarding your application, but I thought this was worthy of mention because it may save you some headaches in the future.

Your project sounds intriguing. Care to share some (non-proprietary) info on what you're actually doing?
 

Toad

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This is awesome.Thanks to you all!!

To make it simple its to grow algae. LED work great but if we can do it with less power then we are on way to a world changing way to process waste in any environment. (also depth is key...LED don't do that)

As soon as we get some good photo logging going on I'll post what we can show.
 
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