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I'll take lasers for $800, Alex
December 10, 2004 3:58 PM   Subscribe

Sam's Laser FAQ is an online bible for laser enthusiasts (of all shapes, sizes, colors, and creeds). Curious novices can start by learning how lasers work and what is inside those nifty green laser pointers. Graduate students, why not fix up that large frame Argon-ion laser sitting the back of the lab? Or just build your own? Of course there are lots of pretty pictures and for hobbyists not terribly interested in glorious amounts of light, don't miss the wonderful discrete semiconductor test guide thrown in for free. And above all, MeFi, let's think safety.
posted by fatllama (17 comments total)

 
This site has been so useful to me I was very surprised when I found it hadn't been posted here yet (let's hope my search-fu was sufficient). Oh and let's try to keep this nonsense [site has sound] to a minimum, ok?
posted by fatllama at 4:01 PM on December 10, 2004


US Warns of Terrorist Lasers!!!!!

Now they're warning us that someone's going to get an eye put out, playing that way with the lasers.
posted by salsamander at 4:05 PM on December 10, 2004


Agggghhhhhh! The goggles! They do NOTHING!

I wanted to build a really BIG laser that was powerful enough to burn through stuff and mount it on an old flatbed plotter mechanism and drive it with a CAD system, but I found out they regulate that sort of thing.

Damn.

Maybe I'll go look at the site and see if things have changed...
posted by Enron Hubbard at 4:29 PM on December 10, 2004


Now all we need is a giant foil ball of unpopped popcorn.
posted by Meaney at 4:29 PM on December 10, 2004


You beat me to it, Meaney.

Curses.
posted by TeamBilly at 4:34 PM on December 10, 2004


salsamander beat me to it, too. Foiled again!

Seriously though, that laser-shining-into-cockpits is a real thing, and it's very dangerous. One of my best friends is an Army helicopter pilot, and a couple of his fellow pilots had their vision seriously damaged by someone (they allege bored Russian troops) shining high-powered lasers into their choppers as they flew patrols in Bosnia.

Might not have been the best time to put that site up, or FPP it here... but you couldn't have known, fatllama.
posted by zoogleplex at 4:56 PM on December 10, 2004


zoogleplex - Ack, you're right. That'll teach me not to keep up with the latest terror warnings. I guess now my only hope for boarding a plane home this holiday rests on quonsar not, in fact, being employed by Homeland Security.
*crosses fingers*
posted by fatllama at 5:13 PM on December 10, 2004


Outstanding site. But hey, I need another hobby like I need another hole in my head.

I would love to make holograms, though. If you haven't seen a real 3D hologram, you've really missed out. When I was a physics major, some 20 years ago, I made one of a 6-sided die ("dice") around which I placed a strip of 1" film. On reconstructing the image, it was like that die was -there-, but it wasn't. Freaky.
posted by neuron at 5:25 PM on December 10, 2004


Eh, Sam's Laser FAQ is extremely well known to anyone with even a passing interest in lasers and how they work. Just posting it to MeFi isn't going to arm any terrorists.

Though, you do still have to watch out for asshats with lasers, but we've had to do that since before diode pointers fell to the 2 buck range and available in every convenience store on the planet.

Don't point lasers at aircraft, moving or not. Also don't point them at cars or from cars. I'm pretty sure pointing a laser at any aircraft is a felony in the US, and I think pointing a laser at any vehicle is a felony in California, and I'm pretty sure pointing one at any unwilling participant is at least a misdeamenor in California as well.

I love lasers, I've been mucking about with them since Helium Neon tubes and solid state drive transformers became actually affordable. Though, it's difficult to have fun with a laser and still remain totally safe and within sensible operating procedures. Beaming one of those scanned cones-of-light tricks through a fogbank and sticking your head in it is just way too much fun to pass up.

Those insanely bright frequency-doubled green pointers are now on the open market and getting cheaper and cheaper. I want one, but I don't want every careless e-tard and grabass from here to Goa and back to have one. I've only played with one once, and it took about 15 seconds before I accidently scanned it across a group of people at a campout I was at, when I was intending to aim it only at some near-by hills. I said "Woah, cool. Put that away, would you?" and handed it back to him.
posted by loquacious at 5:28 PM on December 10, 2004


Rather than take down the plane with a laser, NASA flies the plane with a laser.
posted by caddis at 6:22 PM on December 10, 2004


Enron, their used to be the occasional CO2 cutting laser on eBay. I haven't checked in a while though.

Lasers are amazing things, even those pen lasers. In grad school a buddy and myself had a habit of breaking into labs and playing with stuff. One of the things we did was borrow a very expensive Milles Griot HeNe laser. We waited on top of the roof till the drunks started evacuating the bars and had some fun. This was before pen lasers I think, or at least they were terribly expensive. Some people were amazed by the darting light on the sidewalk (we were stupid, but not stupid enough to shine it at somebody) and one person was very pissed off.
posted by substrate at 7:15 PM on December 10, 2004


Having only taken (and forgotten in a drunk and drugged haze) elementary physics in college, a what altitude or distance do the green key chained laser pointers have enough power to damage eyesight.

Really, I have no desire to be an ass, I'm just really fascinated that something powered by a watch battery could retain enough of its power at that distance to cause damage to the retina.

Also, is there any precautions that could be taken to filter out coherent light. Some sort of coating on cockpit glass or even special glasses?

You would think if there were, they would hand them out to every high school principal who's officiated a graduation. There is always some strap-on who's thinks its hilarious to shine them at the inevitable bald spot.
posted by PissOnYourParade at 8:52 PM on December 10, 2004


Thanks for the ebay tip, substrate. I'll have to check that out.

Though, you do still have to watch out for asshats with lasers

I have finally found the perfect name for my new band - Asshats with Lasers.

Sweet.
posted by Enron Hubbard at 5:51 AM on December 11, 2004


POYP: They make protective goggles for specific wavelengths of light or ranges of wavelengths of light, and they generally have a corresponding color tint to them.

As far as I know, to block all coherent light in all visible frequencies and near-visible frequencies like UV and infrared, the filter would have to be pretty much opaque. Lasers - especially solid state lasers or semiconductor lasers - generally only output specific and well-known frequencies of light. 635, 650 nanometer for red diodes, 532 for the green ones (With a crapton of energy in the infrared-band at about 1000 nanometers for the crappy green pointers without an IR filter).

This would make adding filters to cockpit windows rather easier, but would still add a tint that would probably be unacceptable to pilots, and it would only block specific ranges. Tunable dye lasers or multi-spectral tunable "white light" lasers are pretty easily accessible to the hobbyist in high wattages that would easily cook a retina in microseconds.

The effective distance, altitude or range of any laser varies on the type of laser, how powerful it is, how well it is focused, the quality of the optics, and atmospheric conditions. More moisture or particles in the atmosphere would generally decrease a laser's range.

Out in the boonies, one can use a laser diode pointer for looking for retro-reflective painted signs or plastic reflectors on signposts at night. I've bounced back flashes of light bright enough to stun myself off of such signs from more than 3-4 miles away.

Granted, at 3-5 miles, most pointers have a beam so expanded that it's up to a dozen feet or more across, but it would still be a not-so-good idea to stick your eyeballs in the beamline and look towards the source.

So, for a nicely calibrated red diode or green frequency doubled crystal+diode, maybe running it a little hot with some extra voltage, I'd say a 5mw+ laser is potentially hazardous for up to 10 miles.

It depends on so many factors though. It's not unimaginable that a badly-focused laser beam could become much more dangerous through being refocused by cockpit or window glass, reflections off of concave surfaces, or otherwise being accidently re-concentrated.
posted by loquacious at 10:00 AM on December 11, 2004


Piss: there's a detailed answer to your question re: power to blind, in the Laser FAQs (inneresting that LASER is now Laser, but FAQ is still FAQ...)
posted by five fresh fish at 10:06 AM on December 11, 2004


FFF - I stopped capitalizing laser the same day I heard the verb to lase and the gerund lasing used in conversation. Anyone up for some faqing this afternoon?
posted by fatllama at 11:53 AM on December 11, 2004


I'm wondering how long till they come up with an automated laser blinding system, like I read about in a sci-fi novel, the system would point the laser at any lenses it could detect, people looking at it with binoculars ect.

I have read about an existing system that can detect cameras by looking for lenses(for finding security camers/hidden cameras), so I think the only reason this hasnt been made is because of humanitarian reasons. Which i think is a good thing.
posted by Iax at 2:12 AM on December 12, 2004


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