LASER protective glasses

[TinkeringSteve]

Howdy, folks!

I thought to myself, now would be a good time to tinker with some lasers.
For now, of the "< 5mW, Red, Won Hung Lo" laser diode from ebay kind.
Especially since the experiments will involve deliberate bouncing off lasers between mirrors, I also thought now might be a really good time to get a clue about proper eye protection for such fooling around.

I assume it's not a good idea to just buy something willy nilly that says "laser protection glasses", but something that has known specs and are made for the outlined purpose (save for bouncing between mirrors and laughing like a madman).

So, what would you recommend me to get?

[noname4me]

+1

 I'd like to find out about the safety aspects too,  from someone who knows rather than just reading websites

Sent from my SM-G935F using Tapatalk

[TinkeringSteve]

Well, I don't trust things to be optimal circumstances. Not to mention that an accident with such a laser is at best bloody unpleasant.

Having extra protection won't hurt.

I did experiment with some green glasses that were said to be against lasers some use for doing some cosmetic stuff with, by looking through them at red things which were still pretty red, so those things are apparently not so great.
I would have though that green filters would hinder red, but apparently those were not very effective filters.

[TinkeringSteve]

The glasses were green, i.e. green light passes better than other wavelengths. So I would have expected that red gets through much worse, but, well, not by much apparently.

Thanks for the warning about cheap "unclean" lasers, I had never heard of that.

[BBBbbb]

Real protective glasses won't just have the "opposite colored" lenses for protection, those are probably cheap crap and nothing more.
For example I have never seen red glasses for 532nm (green) lasers, they are usually orange(-ish) and quite transparent.
For example mine are the darkest I've seen, and I've seen many green laser glasses:


With your glasses you should get some kind of technical specification/declaration of conformity, stating all the affected wavelengths and the level of protection at those wavelengths, and as expected it should cover also the auxiliary wavelengths that blueskull mentioned (with Yb:YAG you could be pumping with 940nm)

I've seen many manufacturers of these laser protective glasses, just google and see if they state technical specifications clearly for their products. I definitely wouldn't go the ebay way, but just as a warning I've never paid less than 100 USD for any of my protective glasses, but mine are "medically approved" meaning extra charge.


Now, having said all of this, you won't be able to do a damn thing with those glasses. Since you mentioned you want to bounce them off of mirrors it means you'll have to align the mirrors, and you don't see the laser if you have your glasses on, so your option is to risk it or use a pilot/aiming beam (in your case a weak green laser if the main one is red). Using a pilot beam adds complexity to your project because it takes some good planing of the beampath to align it with the main beam.
I usually risk it, except when touching the beampath of the CO2 laser or moving around the KTP in the 532, since it might bounce off of whatever I'm using to move the KTP. 


P.S.
If you're into lasers and near Munich on June 26-29, there is a fair there: "LASER World of PHOTONICS", some really cool and nerdy exhibitions every time.

 
 

[crazyguy]

It depends on what laser wavelength you are working on. Normally the OD (Optical Density of the Lenses) for that particular range of wavelengths will be marked on the glasses/goggles.

Laser Safety Glasses
https://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=762

To Select Laser Glasses, Goggles, Barriers, Windows or Signs you'll need to know the following:
http://www.lasersafetyindustries.com/Selecting_Laser_Safety_Glasses_Goggles_and_Protection_s/55.htm