Blue or ultra violet

[TJ 47]

Hi everyone,
does anyone have an opinion on what laser i should get because i wanted one with an output of at least 150mW so it could burn things
and go very far. And i have a choice out of a blue laser and an ultra violet so can anyone give me advice?

 

[nanoWatt]

You'd want to be very careful with anything UV, because your eyes focus it quite well, and you can't see it. UV lasers are used to cut fabric in some industries, so that's a consideration.

For burning stuff, the best cost is usually found in green. From what I've read, even IR doesn't really burn stuff more than other frequencies, unless they can absorb the light well.

You will also find blue objects would be more difficult to burn with a blue laser. I'm not sure how much power you'd need, but I think green ones of at least 30-50mW can do small burning of black objects like tape.

Before you start burning stuff, it would be good to read up on the safety of lasers through this forum.

 

[TJ 47]

yes green would proberbly do the best but i dont know why my friends think that blue is more powerful than green and red (with burning things)
but aw well your proberbly right i wonder if i can get a green laser module
that has ajustable output, better do some research
Thanks

 

[Shreknow91]

if you get a burning laser, you should get laser shades, the more respectable companies are Novalasers.com, laserglow.com, and optotronics.com

what ever you do DO NOT go to wicked lasers for the lasers, they are overpriced and underpowered

 

[nanoWatt]

I know some of the companies in China will custom build you a laser. I believe CNI will, and I know that laserbtb does, as I am working with them on a powerful greenie. The manufacturers will typically have the shades as well.

 

[Shreknow91]

i dont think CNI will work with individual people, only companies.
im not entirely sure

just shoot them an email and ask, laserbtb i think is now known as S-KY lasers
btw

 

[nanoWatt]

Thanks. I didn't want to just recommend one company since people tend to think it's spamming. S-KY lasers is very responsive to emails. I haven't worked with CNI but they were the only other one I could think of. Anyway, if need be I could use my internet company.

S-KY seems to be knowledgable about using TEC (Thermal Electric Cooling) to allow lasers to run at higher power for longer. The laser I ordered from them a few days ago is spec'd to run 10-mins continuously before attenuation sets in due to heat.

I would also like to thank drlava for introducing this company to me via a post. His recommendation to me regarding TEC was also to "add a large heatsink on the output transistor on the power supply board", then I'd be able to run it over an hour on a single charge of the 18650 cells.

However, I needed a portable laser that is fairly durable, can project 1-2 miles for aligning antennas. So while I will have a laser that can burn stuff, my use is more long range.

If you want a serious burning laser, try researching CO2, but be sure that it is aligned with a 2nd visible laser so you can see. CO2 lasers are used for cutting and welding metal. Definately need goggles, and the 10.6 micron wavelength reflects very well off of metal, so you'd have to be careful. I'd try around 5 Watts or so for some good burning. However, being invisible, it is critical that you have an overlap beam, of perhaps green.

 

[allthatwhichis]

Burning with a laser has more to do with power and focus point than wavelength. It may be a tiny, insignificant amount easier to focus a blue laser than a green or red laser due to the wave size, but not enough to matter when trying to burn things. We're talking a 200nm difference. I think that is what your friend is thinking about.

200mW of coherent light in two different wavelengths is still 200mW. They will burn the same whether they are green, UV or IR, although there may be a small veriation given the surface you are burning. It may reflect one wavelength a little better than another...

The main think you need is to focus the beam. The smaller the beam the more photons are hitting the same "point" on the surface you are burning. the more photons impacting the surface the more "damage" will be done.

Um, I am making an assumption from your first comment... You can get a 150mW UV laser??? :candle: Is this near UV, 405nm, or true UV, <390nm?

 

[nanoWatt]

You are right that power and focus are important. I recommended the CO2 because they tend to be very efficient, and even 25W is not too difficult to come by. I have never built one, but from reading, they seem easier to create than other gas lasers for what you get.

For getting power, efficiency is very important. Wavelength is more important if you want that laser coolness factor of seeing the beam. But yeah, the difference between UV and IR depends on the material you are burning. It's about imparting enough energy to vaporize the material.

I've seen a multi-watt red laser put a nice black burn mark on a thick yellow pencil that was swiped in front of it (probably 0.25 second contact).

Also you will notice that blue and UV can be focused down more than green or red, so you can get finer burn patterns.
For poweful UV, I'd look into a Nitrogen laser. But AFAIK, they are typically pulsed.

 

[TJ 47]

I like the idea for a co2 laser they are extreamly powerful but the things to make it normally have a high price like the transformer and the tube that the light is foccossed through and i dont really have a very high buget because from what ive heard about co2 lasers is that they cost up to $10,000 and the cost doesnt go below $2,000. But i still like the idea.
Nitrogen laser also sounds like a good idea but your right they are usually pulsed but they can be made to have a very high output but only for a split second so thats something for me to think about.
Thanks everyone.
:thumbsup: