[damnfine]

Interesting that he compares them to firearms, and all that entails. With power levels increasing, we may see a viable laser rifle soon, and with it, a need for a new regulatory structure (or adoption and expansion of an existing one, atf, etc.) They seem to have many of the same public safety aspects, but will someone popularize a legitimate 'Sporting Use' for these devices before they are sold as 'Death Rays to Blind Everyone and Set the World on Fire', And deemed unsutable for mere mortals to own? I hope so. I guess based on this article, you could sell a kit without much liability.

[throwanem]

> we may see a viable laser rifle soon

We won't. It's been a while since I compared the muzzle energy of a rifle bullet and that of a relatively powerful laser, and I don't have the time to dig up the comparison again right now, but the tl;dr: is that we won't see an even theoretically man-portable laser that can put a hole through someone for a very long time, if ever. Setting things on fire and damaging light sensors, sure - but those tasks are absurdly easy by comparison with rearranging bulk matter.

[adrianN]

A rifle has a muzzle energy of a couple kilojoules. So you're looking at lasers in the kW power range. I doubt that you could do comparable damage even if you could deliver comparable energy. Flesh doesn't conduct heat terribly well and vaporizing a centimeter of skin is not very lethal.

[StavrosK]

Sure, but who hasn't thought of turning their enemies into zebras?

[dsfyu404ed]

Just throw an Arduino, some servo motors, a camera and some ML on it and you can keep the squirrels off your bird feeder.

edit: if it's not obvious this is a joke

[atemerev]

I don't think so. Lasers are ineffective as lethal weapons (they are very effective as blinding weapons, which is probably worse and inhumane).

[Filligree]

I don't know about you, but I'd rather be blinded than die.

[joncrocks]

I don't think you get a choice:

https://en.wikipedia.org/wiki/Convention_on_Certain_Conventi...

[gambiting]

If I absolutely had to pick, and the choice was between 1) get shot and maybe survive; or 2) 100% chance of getting blinded - I'd pick the first one.

[stavros]

Why are you comparing a weapon that has to hit a whole person and misses to a weapon that has to hit a 5mm retina and somehow never misses?

[jdietrich]

It's not difficult to track eyes consistently using computer vision. It's not difficult to aim a laser beam using a mirror galvanometer. If you're struck in the eye with a UV laser beam, the blink reflex doesn't kick in - by the time you've noticed the pain in your eyes, it's already too late. The beam doesn't have to track with particularly high accuracy to cause certain blindness, especially if there's an array of beams.

A decent hardware hacker could build an area-denial laser turret in a long weekend with a couple of hundred bucks of parts. I hope to god that nobody ever does.

[wnkrshm]

A UV-laser would be humane, since UV (and shorter wavelengths) will interact with the outermost portion of your eye - visible light or the near IR (up to 1500) is what your imaging system operates on and it's focused onto the retina.

Edit: Also, the blink reflex isn't fast enough to save you from damage if the Class is higher than Class 2 (and even then it's a roll of the dice, since there are some who don't have that fabled reflex).

[pjc50]

A sufficiently powerful laser - over 0.5W - can cause blindness from diffuse reflection. A 100W laser fired into a room with white walls for a fraction of a second can permanently blind everyone whose eyes were open at the time.

[wnkrshm]

cause

a) you can't see when you're being shot at b) it suffices if there is a sufficiently large (to you invisible) reflection within your field of vision c) you can automatically scan a whole field very quickly, invisibly, silently d) the laser spot gets larger at a distance, so the laser is not a pointer but a shotgun cone with 2m diameter

[matthewmacleod]

I think the thing is though that it doesn't. It just has to scatter off of something else in the wrong way, and boom.

[atemerev]

Because lasers are usually continuous and even reflections are very dangerous.

[anfractuosity]

I wonder how practical a portable laser gun would be, as I'm imagining a laser diode array would need to be amazingly powerful (I'm assuming much greater than the 40W version in the video?) and they'd require a very beefy power source.

It seems diode lasers are up to 60% efficient?

It looks like you can get extremely high power pulsed laser arrays though.

[dhimes]

It's not so much the power as the total energy delivered that matters. So, in that sense, it will depend on the batteries (or whatever storage mechanism they use) as much as the lasers themselves.

[anfractuosity]

Yeah definitely, I can't help but think the power source needed would be very heavy too.

[rini17]

Who makes you unable to help yourself? Say, one watt delivered onto the retina can do damage very quickly. One AA battery can easily supply that.

[anfractuosity]

Sorry I wasn't thinking about a system capable of blinding people, those do definitely exist though. Also there are devices such as 'dazzlers' which are intended to cause non-permanent damage.

[dhimes]

Yeah, we were talking about something really fun, like being able to melt a boulder or something. %^)

[wnkrshm]

It's been researched in the 80s/90s. The best solution was a gas-dynamic laser with a Po-220 (the activity of U238 within its entire 10k years halflife packed into a time of two weeks) reservoir as a heat source.

[anfractuosity]

Very interesting, I'd never heard of a gas dynamic laser before.

Edit: Is it the Stavatti device you're referring to? Apparently there are some claims that it was a hoax.

[wnkrshm]

Oh thanks, I've looked into it again and it seems it's highly controversial. I mean, even if it wasn't a hoax, the design is pretty much infeasible if you need a heat source that you can only store for less than a week and that'll kill everyone within line of sight if its container is breached.

[agumonkey]

I also wonder how quickly damage occurs when using all 8 beams through to focusing lens.

[bfu]

What about 3D printed lasers?