PSA: A 200 mW 532 nm laser is not a laser pointer

[Mark R]

I was sitting in the front row at a lecture, and the lecturer insisted on using this as his laser pointer. It was surprisingly uncomfortable on the eyes, and left trippy grey trails behind the spot in my vision, so I couldn't actually see the slide.

Just when I thought it couldn't get much worse, the audience are asked to point stuff on the screen out, so the laser gets passed around. Cue beam going every where and glinting off people's specs and stuff. (That's how I found out it's output).

I also used to have a 50 mW laser, but I don't recall it being as bright as this one.

 

[Joseph F]

LOL, that's ridiculous.

 

[jagec]

I agree.

That said, I bought a 5 mW green laser pointer off of amazon for $4, and it's STILL too bright to be used as a presentation pointer. Crazy!

 

[DaWhim]

wow....the guy is retarded. i would say anything anove 20mW need a safety goggle

 

[Rubycon]

Was it a pen with a <200mW label?
Chances are it was considerably below 200mW CW 532nm. Many of the hopped up pens peak near this figure but drop quickly due to overheating of their pump diodes and vanadate! Just not possible to cram in a sufficient cooling system into those.

That said, it's very irresponsible to use said device as a presenter and even more irresponsible to pass it around to the audience! If someone looked into it they could be blinded immediately! Also one thing commonly overlooked on these devices is the lack of any IR filtering so even though they may be putting out far less than advertized 532nm there could be class IV levels (>499mW!) lurking in the 808 and 1064nm range! Might as well pass a (loaded) Sig Sauer around.

(in the case with a gun at least people know what would happen if they did the un-thinkable!)

 

[RavenSEAL]

200?

 

[Uhtrinity]

I doubt a lot of the stuff coming out of china is even regulated. Last year I bought a few cheap airsoft guns and they came with some super bright red pointers that are most definitely not safe. If that pointer is truly in the 200mW range i would be a Class 3B which does require goggles. I suspect it was somewhat lower, but still too bright.

 

[DrPizza]

We were just talking about lasers in my physics class today. The students asked why I didn't have more powerful lasers - they were sure that I was the type of person to have a bunch of lasers that could start fires or at least pop balloons. Said I, "over the years, doing demonstrations and with other people handling lasers in the class for legitimate reasons, I've been hit in the eyes multiple times from the beam being reflected accidentally off something reflective. These cheap $2 dollar store lasers aren't powerful. I can blink before damage is done. Those more powerful lasers - the damage is done BEFORE you have time to blink. I like my eyes. "

 

[Imp]

Should sue Professor (school) and profit...

 

[slayer202]

god forbid you speak up about it

 

[FeuerFrei]

Sounds more like a designator. Target designator, IYKWIM.

 

[Rubycon]

We were just talking about lasers in my physics class today. The students asked why I didn't have more powerful lasers - they were sure that I was the type of person to have a bunch of lasers that could start fires or at least pop balloons. Said I, "over the years, doing demonstrations and with other people handling lasers in the class for legitimate reasons, I've been hit in the eyes multiple times from the beam being reflected accidentally off something reflective. These cheap $2 dollar store lasers aren't powerful. I can blink before damage is done. Those more powerful lasers - the damage is done BEFORE you have time to blink. I like my eyes. "

Any time a class IIIa or higher source is present and the risk of reflections is real ocular protection is a must.

Popping balloons can be accomplished with a relatively low class IIIb power of ~30mW. It must be dark colored and well collimated with the waist near the point of contact but it will go. The balloon needs to be well inflated too as sometimes it will make a tiny hole pissing out the contents instead. :biggrin:

For ignition (without accelerants) class IV powers are nearly always required. The 445nm diodes found in projectors are quite popular with the laser community for this task. 2+ WATTS of CW power is possible and can ignite paper/cardboard from considerable distance. These are quite dangerous and should NEVER be placed in the hands of untrained individuals.