Beam Question (532nm)

[J0SHUA]

I have read a ton and I still don't quite understand something. Every visible beam seems to stop at some point (it appears to stop) and I kinda understand why, but is there a way to make a 532nm beam go farther, or will a 3W laser go farther than a 200mw laser? I want something that is extremely bright and visible at night (for pointing long distances), I would like to have the beam as thick as I can get it, and I'm not sure if a beam expander would do the trick but it sounds like it might help. I don't really care if it burns or not, and I don't care how much it costs either...

All advice welcome and appreciated greatly, thanks.

 

[Livinloud]

3W 532nm will set you back $6k so I hope money isnt an issue

 

[NightExplorer96]

You are correct! A beam expander will definitely help in regards to keeping the beam tight and focused which in turn, makes it visible farther.


Power somewhat determines the beams visibility, the main factor is a lasers wavelength. A 200mW green laser will have a more visible beam then let's say a 1W blue laser.

Another factor into determining a lasers beam visibility is the amount of "particles" in the air. The beam of a 5mW red(which normally, the beam is invisible) can be seen quite easily if enough particles are present in the air. Long story short, the best wavelength for you would be 532nm.

Here is a good company which has what you need to get started:
LP 515nm 532nm 1-150


Make sure to also "check" the box marked "IR filter installed"!!!

Best of luck!

 

[trencheel303]

A 200mW green will go farther than you think (and is probably brighter than you think). Distance won't really come into it as over a certain distance the beam will just converge into a central point(assuming it is you who is holding it). It is fun seeing a dot on clouds and distant trees though, which is not at all out of the reach of a good 200mW.

 

[Atomicrox]

All beams appear to stop at the same distance, no matter what power or wavelength. There has been a very long discussion here about the causes of this, you can probably find it if you search. Some think it stops where the lowest layer of the atmosphere ends, due to the lack of aerosols to scatter the light. Others think it ends at the vanishing point, due to perspective.
There's nothing you can do to "improve it", one way or the other.

Of course in reality the laser beam goes on and on until it hits something

As for the dot, you can improve the visible distance by lowering the divergence, increasing the power or using more visible wavelengths. In my experience 638nm red is the best, as it scatters less and has less of a visible beam then green (the beam makes it harder to see the dot).

 

[CheeseHasLeafs]

Some think it stops where the lowest layer of the atmosphere ends, due to the lack of aerosols to scatter the light.

If that were true then wouldn't the beam appear longer if you had it at an angle to the sky, as opposed to perpendicular to the sky (well, as perpendicular as you can get it, anyway). From my experience, it doesn't seem to.

@OP Regardless, yes, what Atomicrox said is quite right in that all beams appear to stop at the same distance. A 3W 532nm will cost a lot for no real gain in perceivable beam length. Might as well get a 50mW because that will go the same distance.

What do you want to use it for? The beam expander will certainly improve divergence, but it will increase the beam diameter, which also sounds like something you want, tho I have to say it wouldn't really make the beam look like it's longer. In fact, if the visible beam length is due to the vanishing point of perception a thicker beam would look shorter (but not by much. Most likely not by a perceptible amount).

 

[Atomicrox]

Yes it would. I'm more fond of the perspective hypothesis

 

[J0SHUA]

3W 532nm will set you back $6k so I hope money isnt an issue

I would love to see a $6k portable handheld pointer, that would just be to awesome so if you have a link to something even close to that I would love to see what it looks like...

You are correct! A beam expander will definitely help in regards to keeping the beam tight and focused which in turn, makes it visible farther.


Power somewhat determines the beams visibility, the main factor is a lasers wavelength. A 200mW green laser will have a more visible beam then let's say a 1W blue laser.

Another factor into determining a lasers beam visibility is the amount of "particles" in the air. The beam of a 5mW red(which normally, the beam is invisible) can be seen quite easily if enough particles are present in the air. Long story short, the best wavelength for you would be 532nm.

Here is a good company which has what you need to get started:
LP 515nm 532nm 1-150


Make sure to also "check" the box marked "IR filter installed"!!!

Best of luck!

Thanks Greenlander, thats the kind of answer I was looking for, I'm still new to all this and I can only read for so many hours each day. But why is it so rare to see anything over 200mw?

A 200mW green will go farther than you think (and is probably brighter than you think). Distance won't really come into it as over a certain distance the beam will just converge into a central point(assuming it is you who is holding it). It is fun seeing a dot on clouds and distant trees though, which is not at all out of the reach of a good 200mW.

trencheel, yes you are right. A 200mw will go very far, but I want to know how to take a laser that goes extremely far, and build one that goes even farther... (I'm talking about the visible beam)

All beams appear to stop at the same distance, no matter what power or wavelength. There has been a very long discussion here about the causes of this, you can probably find it if you search. Some think it stops where the lowest layer of the atmosphere ends, due to the lack of aerosols to scatter the light. Others think it ends at the vanishing point, due to perspective.
There's nothing you can do to "improve it", one way or the other.

Of course in reality the laser beam goes on and on until it hits something

As for the dot, you can improve the visible distance by lowering the divergence, increasing the power or using more visible wavelengths. In my experience 638nm red is the best, as it scatters less and has less of a visible beam then green (the beam makes it harder to see the dot).

Atomicrox, I have read most of the discussions here about why the beam appears to stop. Those discussions are what caused these questions. I have even seen some videos showing the beam ending and it seemed to me that different builds of the same 532nm seemed to travel farther than the others, and I wanted to know why? It just made me feel that the builds that seemed to have a brighter more visible beam went farther than the others... As for the dot, I actually care more about the beam, but if what you are telling me is that all beams will end at the same place, then yes, I would start caring about the dot...

If that were true then wouldn't the beam appear longer if you had it at an angle to the sky, as opposed to perpendicular to the sky (well, as perpendicular as you can get it, anyway). From my experience, it doesn't seem to.

@OP Regardless, yes, what Atomicrox said is quite right in that all beams appear to stop at the same distance. A 3W 532nm will cost a lot for no real gain in perceivable beam length. Might as well get a 50mW because that will go the same distance.

What do you want to use it for? The beam expander will certainly improve divergence, but it will increase the beam diameter, which also sounds like something you want, tho I have to say it wouldn't really make the beam look like it's longer. In fact, if the visible beam length is due to the vanishing point of perception a thicker beam would look shorter (but not by much. Most likely not by a perceptible amount).

CheeseHasLeafs, you kind of hit on something... if you were not pointing the beam in the direction that would cause it to travel through the troposphere, wouldn't the beam be visible until you could no longer see it, instead of just stopping at some point???

As far as what I want to use it for, I just want a pointer that will travel the farthest I can make it go, the brightest I can get it, with a nice thick beam.

Thanks for all the help guys...

 

[Livinloud]

afaik you'd have to contact CNI or someone and have it custom made. They have lab styles up to 18W in 532nm but iirc the handhelds stop just above 1W. They would have to build you something and the $6k was a guess on price. afaik no one sells a legit 3W handheld, they would all have to be custom built but I may be wrong. A 3W 532nm handheld isnt something I search for, ever lol

 

[Atomicrox]

I can guarantee you that more power does *not* make the beam go further. I have tried this with every single laser in my sig and all those that have a visible beam end on the same point. Do you mind linking one of those videos? Might be an illusion of perspective.

 

[Livinloud]

Well they might seem to end at the same point when viewed from behind. Did you happen to have someone observe them from 90 degrees off at a distance? I would be interested to see a shot like that, although it takes 2 people and at least a mile of distance between you to get a good perspective. Might have to ask my buddy to let me know when he is leaving work so I can shine mine in the air and freak 99% of Tampa out :eg:

 

[Atomicrox]

You'll need a lot of power to see a beam sideways from a mile away - maybe pushing one of the new diodes very hard. My 3W dominator is barely visible from 100m away.

But yes, sideways it gets strange. It always looks like the beam is pointing "the wrong way" and you completely lose your sense of direction/distance.

On an interesting note, power seems to make a lot more difference in brightness when viewing sideways

 

[trencheel303]

Thanks Greenlander, thats the kind of answer I was looking for, I'm still new to all this and I can only read for so many hours each day. But why is it so rare to see anything over 200mw?

The laser uses a process called DPSS (diode pumped solid state) which actually uses an Infrared diode to fire at some crystals which alters the frequency of the light, causing it, in the case of this type of laser, to exit the aperture as green. The "pump diode" has to be many more times powerful than what the pure green output measures as, because of operational losses. That's it very much in a nutshell - and is about all I know about it. Read more about DPSSLs here: Diode-pumped solid-state laser - Wikipedia, the free encyclopedia

trencheel, yes you are right. A 200mw will go very far, but I want to know how to take a laser that goes extremely far, and build one that goes even farther... (I'm talking about the visible beam)

The problem with going higher and higher in power is you get diminishing returns. The difference between a 50 and a 200mW for instance will be about the same as 200mW and 1W - but the latter jump will cost you much more. I would also be surprised if you'd see the beam going much farther, as at this stage power isn't your limiting factor.

 

[NightExplorer96]

Thanks Greenlander, thats the kind of answer I was looking for, I'm still new to all this and I can only read for so many hours each day. But why is it so rare to see anything over 200mW?

Thanks for all the help guys...

It isn't too rare to see 200mW 532's. In fact they can be had for about $150-$250 so they can be obtained pretty easily.

Some wavelengths which could be considered *rare*(handheld)at 200mW and/or above are listed below:

473nm
589nm
593.5nm

 

[J0SHUA]

I can guarantee you that more power does *not* make the beam go further. I have tried this with every single laser in my sig and all those that have a visible beam end on the same point. Do you mind linking one of those videos? Might be an illusion of perspective.

This is good to know since I haven't had the time or the experience to see the results myself... And I think your right, it was a matter of perspective...

afaik you'd have to contact CNI or someone and have it custom made. They have lab styles up to 18W in 532nm but iirc the handhelds stop just above 1W. They would have to build you something and the $6k was a guess on price. afaik no one sells a legit 3W handheld, they would all have to be custom built but I may be wrong. A 3W 532nm handheld isnt something I search for, ever lol

Very interesting, and good to know also...

Well they might seem to end at the same point when viewed from behind. Did you happen to have someone observe them from 90 degrees off at a distance? I would be interested to see a shot like that, although it takes 2 people and at least a mile of distance between you to get a good perspective. Might have to ask my buddy to let me know when he is leaving work so I can shine mine in the air and freak 99% of Tampa out :eg:

This would definitely be interesting to see, because based on everything covered here the beam should stay visible, right?

The problem with going higher and higher in power is you get diminishing returns. The difference between a 50 and a 200mW for instance will be about the same as 200mW and 1W - but the latter jump will cost you much more. I would also be surprised if you'd see the beam going much farther, as at this stage power isn't your limiting factor.

This I would have never thought, thanks...

 

[J0SHUA]

It isn't too rare to see 200mW 532's. In fact they can be had for about $150-$250 so they can be obtained pretty easily.

Yes, 200mw can be found, but what seemed to be rare are handhelds that are over 200mw, which I would be interested in, if it made the beam brighter...