I’m contemplating a purchase of a green LASER pointer, one I’ve found says it produces from 45-50 mW on 2AAA batteries, with an operating time of approximately 3 hours. Even claims to burn holes in black trash bags, and has a 20 mile range. Now, I’ve done the math, and the batteries will at least supply the necessary mW, but I’m not sure about 3 hours, and I’m REALLY not sure if the trash bag bit is the least bit true.
So, the questions are;
Is this legal, since it is a class 3 device? (well, 3B actually)
Will a LASER of that power do as they advertise, and if so how quickly?
As for is it worth it? Well, no. A 5mw green laser is already wicked bright. And seeing as you can only use a souped up one at home, you’re going to burn through a few black plastic trashbags and get bored. If you do use the laser outside, you’re opening yourself up to some legal problems if you shine it in someone’s eyes, even accidentally. (From what I can tell, 40 mw is getting very close to the point where even blinking may not be fast enough to prevent some eye damage.)
Precisely! That’s why it’s class III. If we can hold off until tomorrow, I can quote all of the good stuff from the ANSI spec. I went to laser safety officer school a couple of months ago. But, I didn’t certify and don’t use it every day, so I can’t quote it like the real experts. It’s really cool, good stuff.
No offense taken. Actually, I know they’re dangerous, that’s why I asked what I asked. Finally, I’m an arson investigator, so I’d like to examine the end results of a laser related fire. I suppose that I’d like to know if I could get them cheaper than that. Plus, I get to burn stuff with light from across the room. How cool would THAT be?
Well, VERY cool, obviously. Not to mention being able to travel and visit native bush tribes who are just comming to grips with making stone tools and wow them with your ability to create fire at a distance with only a hand gesture and some quiet chanting.
So did you say you’re an arson investigator or an arsonist? (or is one a front for the other)
Being able to burn holes in black trash bags isn’t that impressive. Back in grad school, I was working with a dye laser pumped by an Argon Ion (green) laser. The gren beam not absorbed by the dye proceeded away from the laser toward the wall. It was pretty weak by thi time, and it was a rapidly expanding beam (having been focused down to pump the dye laser), and normally it was stopped by the case on the dye laser. I had the case off to do some tweaking, and I didn’t care about the weak, expanded green beam that was now hitting me in the stomach.
Until I felt a little strange, and looked down. Even weak and expanded, that beam had melted a hole in my shirt! It was a black polyester shirt, which greedily absorbed the beam. Once the beam struck my now-exposed stomach, it simply warmed it a little. But I stopped wearing black shirts in the lab.
Corollary: I’ll bet the hand-held green laser won’t do anything to white trash bags.
2. The eye responds to green much more than to red, so if you have green and red laser pointers of equal power, the green seems much brighter. I think this was the big selling point – when they first came out, someone with a green laser made a big splash because a.) it was green; b.) it was bright. Geek one-upmanship. But green isn’t really any better than red as a laser pointer, especially now that the novelty has worn off.
Any laseer is potentially damaging to the eye, especially if you keep it trained there a long time. If you want a laser pointer that’s green for the novelty, by all means get one, but use it responsibly. If you just want a pointer, get the cheaper red one. It’ll work just as well.
Slightly better, actually, because you can see the beam under most conditions. Makes it really useful for pointing out stars for astronomy. Still, 5mw is more than enough for this application.
