5mW LEDShoppe Green Laser Safety Concerns

[usapatriot]

Hello all,

I suppose this being my first post that I will introduce myself here as well. I've always had an affinity for lasers ever since I was gifted a 1mW cheap red laser years ago. I've been thinking and I may want to collect a few lasers as a hobby. Anyways, I decided I'd like to get another laser this past week and using money left over in my PayPal account ordered a $13 5mW green laser pen pointer from LEDShoppe. Now, I am aware of some of the safety considerations when using a laser pointer but I'd like to learn a bit more.

I've read that occasionally, LEDShoppe's 5mW lasers are over specification making them much more dangerous to the eye. I've also heard they give off a lot of IR light which is invisible and can do damage. I'll phrase my concerns as questions as they will be easier to see and respond to.

Anyways, here are my concerns:

1. Is there any way to tell if my laser is over 5mW? I've heard of there being a device that does this but I don't want to spend money on something expensive at this point. Is there a way of roughly estimating power output?

2. Is there any way of telling how much IR light is being put out, if so, how much would be dangerous to the eye and how exactly would one get exposed to IR light while using a laser? Any methods of blocking the IR light?

3. Obviously, I won't be pointing the laser at any living animal or reflective surfaces. But are there are other surfaces I shouldn't point the laser at?

4. I've read that it is not good to look at the point of light at the end of the beam. However, the general consensus is that this only applies to really powerful lasers, is there some truth to this?

5. Any other safety considerations I should be aware of?

Thank you so much! I'd love to collect a few lasers here and there, but I'd also would like to be keenly aware of any and all safety implications!

 

[photonaholic]

Welcome to LPF. Enjoy your time with us here.

Regardless of stated power, Treat your laser like a loaded gun, always respect it.

As for other surfaces, white walls for extended periods will give enough reflection to make your eyes itch after a few moments. most any glass surface will reflect a lot back, fish tanks can split the beam into multiple beams.

road signs, driveway markers and bicycle reflectors are really bad, since the coating is retro reflective, meaning nearly all light is directed back at the source, regardless of the angle.

I wish I had more time right now, but I'm sure someone else will chime in soon.

I have included a handy guide to assist you in finding what you need.

 

[hakzaw1]

You can seriously mess up a digital camera with a laser as well as your eyes(straight shot). search and read ==read and search-- its mostly all there.

 

[Bluefan]

Making a rough estimate of power is quite hard, I've turned up a red keychain pointer to 10mW, but it really didn't look more dangerous than 1mW. A power meter would be needed to measure the output. This also goes for the IR, unless it's not present, there's not really a way to measure it. At least I'm not aware of it. Detecting it's presence can be done by hacking a cheap webcam into an IR cam (very nice to have around), or a camera with a night vision feature.
Power meters can be very expensive, at least the real deal. But there are cheaper alternatives, some people experiment with homemade tec or photodiode based power meters. Sending lasers to another members to spec them also occurs sometimes.

Assuming we've got 5mW of green and no IR, any diffuse surface is no problem. The spot will be bright, but not hurting your eyes. Glossy surfaces and mirror bounce significant portions of the light, up to 90% in a worst case. For below 5mW, you can get away without safety eyewear if you have a normal blink reflex. I'd be a bit more cautios, like around 3mW. But common sense can perfectly keep you safe here. Above 5mW is too dangerous without glasses, damage can occur before you can react.
Again, if the spot can be looked at without hurting your eyes, it's fine. Around 200-300mW the spot really gets very bright, I'd wear glasses even for the diffuse reflection. Looking up close lowers this off course. Above 500mW you really need goggles. But at these high powers, a direct hit is so dangerous that you should be wearing glasses anyway.

laservision has a nice guide, this explains the whole safety thing.