skylasers 808nm laser pointer

[floridaguy5583]

Hi guys, i recently bought an 808nm laser pointer from skylasers, the laser pointer arrived really fast, i got it and put NEW batteries in it, and you could the see the infrared dot, it was 3x3 mm just like they said, However, it's supposed to be 200mw and it doesn't burn anything, i tried lighting cigarettes, that didn't work i tried lighting matches neither, i tried burning through Dark paper, that didn't work either, i tried doing it in warm temperature, still nothing, i have sent an e-mail to skylasers however they have yet to answer, i sent the e-mail monday, please give me a suggestion on what might be happening.

 

[jwc]

Temperatures won't matter much with an 808nm laser. They simply have output from a diode; there are no DPSS crystals in there that need proper temperature control.

You said this was a pointer? Are you using any focusing optics? You'll probably need some.

 

[davidgdg]

Hi guys, i recently bought an 808nm laser pointer from skylasers, the laser pointer arrived really fast, i got it and put NEW batteries in it, and you could the see the infrared dot, it was 3x3 mm just like they said, However, it's supposed to be 200mw and it doesn't burn anything, i tried lighting cigarettes, that didn't work i tried lighting matches neither, i tried burning through Dark paper, that didn't work either, i tried doing it in warm temperature, still nothing, i have sent an e-mail to skylasers however they have yet to answer, i sent the e-mail monday, please give me a suggestion on what might be happening.

Your problem is almost certainly the spot size.The ability to burn is basically a function of power per unit area. So my 90mw green will make most black plastic and cardboard surfaces smoke with a spot size of ~ 1 mm - giving ~ 115mw per square mm, but my 117mw 405nm will not burn when the spot is set at 2.5 mm (giving only ~24mw per square mm).

Your 200mw 808 with a 3mm spot size is giving you ~ 29mw per square mm which is probably too low. The best spot sizes for non-focusable lasers are greens, hence they tend to burn best.

If you can focus, then any laser over about 50mw will burn.

The other possibility is that the unit is underpowered, but you will need an LPM to test that. Also, it isn't very likely with an 808. They are fairly simple beasts.

David

 

[davidgdg]

Another possiblity is reflection in the near IR. I didn't realise, but apparently many organic surfaces reflect in the near IR. See RAP's post on this thread:

http://laserpointerforums.com/f40/1w-808nm-burns-less-then-loc-46148.html#post621832

Still, I suspect spot size is the most likely culprit.

 

[billg519]

Get a magnifying glass lens in front of this laser and focus the beam into a tiny point a few inches in front of the lens. If it is anywhere near 200mW, it will burn dark objects like electric tape, black plastic, and light dark matches. I hope that you also purchased goggles for this. IR is dangerous as you don't know how much radiation is entering your eyes. Invisible IR is a very effective blinding agent.