Searching for the best distant burner

[Sephiroth1]

Hi everyone, I am a new member of LPF :wave:. I'm trying to find a specific handheld laser that is best suited for burning as far away as possible. Gathering information so far, I've learned this:

1. For distant burning beam characteristics (divergence, round dot and diameter at aperture) are more important than raw power.
2. The lowest divergence I've found so far is 0.5mrad on some 405nm lasers.
3. Beam expander lenses are good for lowering the divergence at the cost of increased beam diameter at aperture.
4. Blue and violet beams are better absorbed than others by most materials (color of material also matters).

So, please suggest where to find such laser. What is the highest power of those single-mode 405nm, while still maintaining the 0.5mrad divergence? I prefer buy one instead of build, since I don't know how, but I might as well learn. Also I can't afford to spend much mоnеy so maybe I'm gonna have to make some sort of compromise.

Any suggestions would be greatly appreciated! :thanks:

 

[jander6442]

12x 405nm with a G-2 lens.

 

[cheech226]

for long distance a 12x is the best. i can pop a balloon at 40' with mine using a 3 element lens

 

[TheDukeAnumber1]

I agree, when my 405nm was still running I could snipe balloons with it. Building your own is good experience but as for buying lazerer.com has good prices.

 

[Teslanium]

If you're going for distance, why not just use a lens farther on down the beam?

T.

 

[DrSid]

Sure you can use different optics, but that is usually the most expansive way.

 

[Teslanium]

All you need is one cheap, simple glass lens.

T.

 

[TheDukeAnumber1]

Sure you can use different optics, but that is usually the most expansive way.

Did you mean that literally, or typo? Cause I guess it could be both.

 

[SpyderFire]

Did you mean that literally, or typo? Cause I guess it could be both.

lol that was a good one.

But yes a 405 with a G1/2 has very good range

 

[DrSid]

Did you mean that literally, or typo? Cause I guess it could be both.

Sorry, but I did not catch the pun ..

 

[TheDukeAnumber1]

Referring to a beam expander, and that expansive could have been expensive.

 

[Sephiroth1]

Thanks for all the replys. So most of you suggest that I should stick with 12x 405nm with G1 or G2 lens like the one here for 96$:

https://sites.google.com/site/dtrlpf/home/diodes/s06j-12x-405-diodes

I also found some 500mW 405nm in lazerer but with no beam specs. The only specs of a powerful 405 laser I've found are in survivallasers.com and they say: beam width-5mm and divergence-1.5mrad, which I don' believe are very good for distance. However I'm not sure if this is the same 12x diode (don't even know what 12x means). So please can u give me some beam specs for those lasers you recommend? Do they become better with the G2 lens? I really prefer lower power but with that illusive 0.5mrad divergence than higher with 1.5 or even 1 - 1.2.

 

[DrSid]

Referring to a beam expander, and that expansive could have been expensive.

Oh I see .. .. I was actually not aware those are 2 different words, so thanks.

I've experimented with many lens to improve distant burning. One big planiconvex lens with focal distance of about lens diameter, coated for specific wavelength .. is all you need !

Common loupe is not good, as it is simple convex, and it has high spherical aberration .. you will not get dense clean dot with it. That's where planiconvex is a lot better. Also some are plastic, and do not pass short wavelengths well.

Photographic lens are quite fine. They have right focal distance, often large aperture, and low spherical aberration, ie they make nice dots. But they contain lots of elements, and that mean losses. Even if they have some coating, it usually don't work well at 445 or 405nm.

I also tried large reflector photographic lens, with 80mm aperture. It has only 2 glass elements, the rest are mirrors, which are usually very effective. But center of the lens is masked by secondary mirror, and that is where the most of the laser beam density is. I could hardly pass 10% of my 445nm through it.

 

[cheech226]

you don't need a g1 lens. i think they increase divergence. altho they do let thru more power