I have both a green and a red 5mw laser pointer and they were fairly inexpensive. I've always heard the warning that cheaper laser pointers aren't UV shielded so you should either be careful (always good advice) or not buy cheap laser pointers and buy an expensive laser pointer:)
I have some material that is very sensitive to UV. They are white beads that turn colors in the sun (UV) or under a UV light. I have a UV light so I can test this out (as well as taking them outside).
They react quickly to UV and return to white fairly quickly as well. I tested both of my laser pointers for UV by shining them at the beads and the beads stayed white.
So, even though this is hardly scientific and specifically it only applies to my two laser pointers I found it interesting and thought I'd pass that information along.
Your cheap laser pointers may not be the UV leaking sources that you've been told that they were.
It's not UV that they leak it is IR. Your cheap green pointer has no IR filter. It will be leaking some amount of IR. Your red pointer is just pure red and has no IR or UV in its output.
I did try using my digital camera but I didn't have a way to filter out the green laser. I don't have safety glasses for a 5mw pointer.
Regarding the IR. I don't suppose it's anything to really worry about anyway. I shouldn't have a problem with it if I'm not pointing the laser at my eyes and if I am pointing the laser at my eyes I'd have bigger problems anyway.
The problem usually comes when you have a pair of safety glasses rated for 532nm, which does not block IR. So you could be staring right at 0.001mW of 532nm radiation and think it is safe, but in fact you are being blasted by an extra 15mW of IR. This is esp so if you are dealing with "low" quality yet extremely powerful lasers. Bob Laser is notorious for high mW 532s (read about it on LPF), but a major part of that is IR. Just giving a wild example, 700mW 532, 80mW IR. That'd pop your eyes within 0.1s from a window pane, even if the IR diverges more than the 532. In short - it gives you "false protection". It might be safer if you are not wearing any safety goggles and using it safely esp outdoors.
Do not stare at any beam straight on. However "accidents" do happen and if you manage to catch a reflection off a mirror or the chairs' legs of polished aluminum or shiny silvery refrigerator, or window panes, microwave oven glass or mirror-surfaced kettle or whatever, you might have a very bad day if you have a high-power 532nm. Lasers behave in a very different way compared to flashlights - totally different animal.
PS. If you read more and lurk at LPF, you'd know that the laser hobby is a deeper hole than flashlights....you have high-end stuff that make Surefire/Titanium customs look budget. But none of the funny talk at CPF. LPF is like a more techie version of BLF? Dunno...
This is sort of off-topic, but since we have so many knowledgeable members, I figured I'd go and ask the experts.
I understand that IR is potentially dangerous because the human eye's blink reflex is only triggered by visible light and with IR being invisible to us, you could expose your eye to a damaging amount of IR radiation without knowing it. And that's all I need to know to stay away from high-powered lasers.:D
Now, there are several IR heaters at a cabin we sometimes hang out at. They look like this one, only much larger.
(Image hotlinked from Wikipedia)
I also understand that the reptile heat lamps they sell at the pet store (the type that emits very little and sometimes no visible, red light) are in fact IR lamps. Some of these heaters come with a warning label but I've never seen any warning about potential retinal damage. There's the usual stuff (hot surface, do not submerge, for indoor use only, etc) but never anything about eye damage from IR exposure.
So... are these safe to use? Why is it that the IR radiation from a high-powered 18650 laser appears to be much more dangerous than what comes out of a large IR heater that operates on 110-230V?
I assume the IR emitted by these heaters has a different wavelength, and is therefore less dangerous, but I could be totally off base here.
In the case of IR I don't think it's necessarily a different wavelength but I'm guessing it would be much more focused (as is the laser). It's also not just the blink reflex but the fact that your iris will be wide open rather than constricted as it normally would be with bright light.
Well, those reptile lamps are flood lamps. You can probably get eye damage from a 10kW flood unit and staring at it from 1m away. But I guess your hair will get burnt first. :)
The IR from the pointers are like "throwers". You can get eye damage by staring at maybe a 100W HID's reflection from 1m away?
It's like a matter of intensity at a particular spot.
And the thing is that safety glasses give a false sense of security, as it filters the green but not IR. So maybe a greenie has 80mW of green and the glasses cut it to a safe 0.1mW. There could be 10mW of IR and maybe when it hits the eyes it's 1mW. Still plent of IR, esp as i've said it gives you a false sense of security and you stare at it straight for a minute or two. You don't stare at a XR-E thrower's output for a minute or two as well.
One question I have about these scenarios with the safety glasses...why would anyone be staring straight into a laser for a minute even with safety glasses?
1. I definitely wont! :D 1, 2, 3 minutes is just an arbitary figure that i gave.
2. Check out the youtube vids above. Definitely out of the world's what 6 billion population, and 1 billion (?) in developed countries, I guess there would be at least a couple of thousand people trying to doing similar things like that either on mirrors or directly. "Horsing around"
3. The actual risk is not very high, but nobody bothers with it until "something happens". It was an accident and i was checking out the glow of the arc chamber of the HID bulb at a close distance. A hot restrike happened and all it took was a near point blank brief flash (not 100% power even) of my 100W HID and a good few hours of slightly puffy eyes and 1 day of a linger flash hotspot in my retina to drill into my head that powerful flashlights could be dangerous.
If flashlights can do that, what more would lasers do....
You can easily add a IR filter to any green lasers. Only green (532nm) lasers might leak IR. There are larger IR filters on ebay as well that you can cut into four.
^ True but the difference in perceived brightness will be slight enough that you won't notice it at all. Don't want anyone to avoid a filter in fear it will reduce beam brightness.
Brightness doesn't increase equally as mW power increases (or decreases), e.g., Double the power won't get you double the brightness.
