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ArcticMyst Security by Avery

Laser best for daylight visibility

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Feb 15, 2016
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I need some recommendations for a laser with a beam that would provide the best visibility in daylight environments. I'm a forester and I want to use a tripod mounted laser to shoot property line boundaries. Basically it will allow me to distinguish between trees standing to one side of the beam or the other. Working distance could be up to a 1/4 mile away from the laser but generally would not exceed 500ft.

From the research I have conducted so far it seems a green 532 nm, 300+ mW, would fit the bill.

What about a 520nm? I read they are more stable and cheaper but I do not want to sacrifice too much visibility and defeat my purpose.

Duty cycle is not an issue as I have devised a remote switch where I don't have to leave the laser on continuously.

Thanks for your help in advance.
 





diachi

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What will the conditions be? Broad daylight - clear air (no smoke)? You need *AT LEAST* a watt to get any decent amount of visibility over any sort of distance in those conditions - and even then it isn't going to be great. That's also a major safety hazard. You might be able to get away with less power by using a pair of green colour glasses, but the safety issue is still going to be there.

Here's a cheaper, easier and much safer way to achieve your goal: A long piece of fluorescent green string.

Not trying to be a downer, just being practical.
 
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Thanks for the reply diachi,

Conditions will be daylight hours, and usually (but not always) under a forested canopy.

Air quality will be clear other than the high humidity.

As for safety I will be the only one around as my work is in secluded areas and I will be wearing proper safety glasses and not standing in the direct path of the laser. I will remotely turn on the laser with an RF switch long enough to determine where the boundary is (couple of seconds).

I currently use the string method you stated and various other methods but I'm looking to improve efficiency and accuracy.
 
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520nm would be your best option in this case. You can get about 1W of it for about $400-$500 depending on sources and would be much more efficient then a similar powered 532nm laser.

Thing is, I believe the duty cycle on 520nm lasers are pretty short unless properly heatsinke so keep that in mind. Even so, 1W of 520nm is going to have a hard beam to see in daylight :yh:

-Alex
 

diachi

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Even so, 1W of 520nm is going to have a hard beam to see in daylight :yh:

-Alex

Being in the shade from the trees will help - that's much different than being in a wide open field at mid day in the middle of a beautiful summer day! Then you still need to take divergence over a quarter mile into account, that's really not going to help once you get further away - especially with 520, seeing as it has worse divergence than your average 532. A beam expander may be a good choice - Alaskan, care to comment? Seeing as you probably have the most experience with beam expanders. :D

Alex is right though, 1W 520 is your best bet. Equivalent power for 532nm DPSS is going to cost twice as much as the 520, and be less stable/durable.

Also - back to safety for a minute - you won't be able to see the beam with safety glasses on, that's the point of safety glasses - they block the laser light, meaning the dot, the beam, everything at or around the intended wavelength. Just a heads up in case that wasn't already clear :)

Ahh yes, also worth mentioning, there may be a potential fire hazard if you are going to be operating anywhere that doesn't get much precipitation. Just something to think about!

Edit: Also, the beam will be most visible when facing the laser (looking down the path of beam) or looking from behind the laser towards the dot, again down the path of the beam. Obviously getting that close the beam would be dangerous without safety glasses. Viewing from side on you may have a hard time seeing the beam, even at 1W.
 
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Thanks Alex,
So in your opinion there would not be a significant difference in visibility between 520nm and 532nm in this application to warrant getting the 532nm?
 
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diachi

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Thanks Alex,
So in your opinion there would not be a significant difference in visibility between 520nm and 532nm in this application to warrant getting the 532nm?


No, 532nm will be marginally brighter - I don't imagine you'd even notice it. The difference in brightness wouldn't be worth the difference in cost. As I said too, 532nm is less stable/durable.
 
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Going to try a 1W 520 and hopefully not burn down the forest! :)
Seriously though I do these jobs in the winter and it stays pretty wet around here and the laser shouldn't be on long enough to ignite anything (just a quick 1-2 sec max momentary flash).

And if my original plan doesn't work, then I still have a cool laser. :) :)
I like tinkering with electronic gadgetry anyways, just never delved into the world of lasers.

Thanks all, I appreciate the insight.
 
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Going to try a 1W 520 and hopefully not burn down the forest! :)

And if my original plan doesn't work, then I still have a cool laser. :) :)

I like tinkering with electronic gadgetry anyways, just never delved into the world of lasers.

Thanks all, I appreciate the insight.

No problemo,

Have fun Mike :p

-Alex
 
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Just be sure that your eyes are nowhere lined up with that beam because you most probably will be getting a class IV laser.
A beam expander or line lens might help you out. I do not have any beam expanders left. A great use for the line lens is painting lines in parking lots so it is a viable tool for this application also. You will need a very high powered laser though if you get into any areas of direct sunlight.
 




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