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What laser has the best beam divergence?

Kloose

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Oct 21, 2019
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Hello,
I would like a laser that goes pretty far so, i'm going to settle on either the challenger 2, red guardian or striker. I'm not sure which laser goes the farthest though, It doesn't say how far it goes on either one so I need help.
 



Encap

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I would like a laser that goes pretty far so, i'm going to settle on either the challenger 2, red guardian or striker. I'm not sure which laser goes the farthest though, It doesn't say how far it goes on either one so I need help.
There is no real answer to your question--really it is a meaningless question with no real answer---a laser light theoretically goes on forever---way further than you will ever be able to see while holding the laser. It depends on everything not the laser/ everything not including the laser. That is why distance a laser can travel is never part of the specifications of a laser.
All of the resellers from China say whatever they are selling that day goes X distance is just marketing hogwash---is meaningless basically---and not characteristic of a laser beam in any scientific real world sense just marketing BS. If you are talking about visibility of a beam and how far/distance that is another thing and determined by a lot of factors.

"How "far a laser goes" is dependent a few things...
First, Divergence.
Generally, reds have better divergence than greens because of the optics used. This does not meant green lasers have inherently poor divergence. With the right setup, the same or better divergence can be achieved.
Better divergence means that the beam will be visible over a longer distance.
Second, the human eye's response to different wavelengths.
Green is brightest. Red and Violet are close to the same "brightness" mW for mW.
Green and red are "easy" for our eyes to focus on. Near UV is difficult. Violet lasers will appear blurry or fuzzy even though the divergence is about the same as what you get with typical red lasers.
This poor perception of Violet makes it look like the beam doesn't travel as far.
Third, atmospheric conditions and Rayleigh scattering.
Short wavelengths (blues and violets) are scattered by the atmosphere (moisture, dust, and air) more than longer wavelengths like green and red.
This means that the beam of a violet laser will be attenuated by the air much more quickly than the beam of a red laser. On the other hand, this makes the beam appear brighter since more light is being reflected towards you. "
From thread: https://laserpointerforums.com/threads/visible-laser-distance-532-650-405nm.44070/
Also see thread: https://laserpointerforums.com/threads/how-far-does-a-1w-blue-laser-go.91009/

All diode lasers have a relatively poor/bad divergence characteristic due to the actual physical structure of a diode laser.---better beam quality and divergence can be has with a DPSS laser/DPSS lasers have better divergence than any diode laser.
See a little bit about it here: https://en.wikipedia.org/wiki/Diode-pumped_solid-state_laser
For an excellent quality DPSS 532nm green hand held laser see: https://www.jetlasers.org/index.php?id_product=72&controller=product#/1-finish-black/50-battery-no/53-switch_type-pl_e_mechanical/52-10x_beam_expander-no/49-goggles-no/31-power_levels-600mw

For serious list of DPSS lab lasers & wavelengths are available from CNI for relatively low but still expensive prices--see here: http://www.cnilaser.com/

Thread about 1W blue laser seen by International Space Station astronaut in orbit 220 miles up above the ground in Texas where a group flashed it at the ISS see : https://laserpointerforums.com/threads/amateur-astronomers-flash-the-space-station-with-1w-blue-laser.72271/

High powered hand held lasers are not toys, they are dangerous and capable of easily blinding you forever.
Be aware and study up on laser safety.
Today's high power hand held laser can permanently damage your eye faster than you can blink an eye.
See hazard chart here: https://www.lasersafetyfacts.com/resources/FAA---visible-laser-hazard-calcs-for-LSF-v02.png
See all about laser safety here: https://www.laserpointersafety.com/
See the eye damage an LPF member suffered from a split second hit in the eye from a 1W 445nm blue laser here: https://laserpointerforums.com/threads/hit-in-eye-with-1000mw-445nm-blue-laser.69469/

Hope that helps get you started.

Please make a Welcome thread/post in the Welcome subforum
 
Last edited:

Alien Laser

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Single mode diode 405nm ;)
Laser can go very far if you have the correct lens some can be seen on the moon scientist use lasers to measure planet's distances its all about the lens i believe but don't take my word i may be wrong :alien:
 

paul1598419

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Lasers used to measure the moon's distance from earth only send back a few photons from the mirrors that were set up there during the moon landings in the early 1970s. They are not 405nm either.
 

cistercian

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Nov 21, 2009
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Solid state lasers do. Yag, ruby, etc. Best divergence. Epic made gas lasers are superior as well. Like solid state,
thermally limited. Diode lasers are the worst by far...
 




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