The link to this video of someone who made a “real pulse gun” that shoots holes through things is all over the internet.
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Is this a hoax?
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If real, would there be any benefits in a refined version for law enforcement and military applications?
As nifty as it is, this would seem to be useless for law enforcement. The effect of a laser pulse on flesh is to cause localized burning. Painful and annoying, but seriously lacking in stopping power as compared to a bullet. The main thing this gun would be useful for is to permanently blind people, especially if a shot missed the target and then hit something reflective and scattered into the eyes of random bystanders.
Wow! It can pop a balloon!
At 850 grams (just under 2 pounds) you’d inflict more damage by using it as a blunt instrument, than actually firing at anybody.
You’d also have to ask how many shots you can get from whatever the internal energy storage is.
The official site has some more details. It has four lithium ion batteries that probably total around 5000 mAh. Those charge a huge capacitor, which holds 100 joules. That’s not a terribly large amount of energy, but concentrated on a small area it’ll easily vaporize a few milligrams of any material. And that’s good for 50 shots. All of those numbers seem plausible enough to me.
If I’m doing my math correctly, the batteries should hold around 60,000 joules, so less than 10% of the available energy ends up in the capacitor. And a big chunk of energy is probably lost with each shot. So it’s really just a flashy but inefficient way to make tiny holes. You could do a lot more damage using those batteries in a cordless drill…
The OP’s link claims a 1-megawatt pulse power output, but the duration is unspecified, so the total per-pulse luminous energy output is unknown. Your link to the inventor’s site claims kilowatt output, which seems more reasonable for a device this small.
When my brother was in grad school working on high-speed imaging (10M frames per second), he used a dye laser that delivered a 1-megawatt pulse. This was one full joule of luminuous output, with a pulse duration of 1 microsecond. He used black Polaroid photographs as targets for testing the uniformity of the output beam; without lenses, the laser would vaporize a 1-inch diameter circle of the top layer on the target Polaroid, making a pretty good “POW” in the process. One day he used a lens to focus the beam down to a point on the target, and when he fired the laser he said the sound was like a stick of dynamite going off; people from down the hall came running into his lab to see if he was alright.
Effective range on 3m (dark surfaces)…you will see a stinging flame and a 5mm stain will remain on target.
I would say the applications are…limited.
Stranger
Nicer holes, but pretty limited range.
It’ll disperse a pack of mallgoths, but that’s about it.
Next up, a forcefield!
I think what the OP may be getting at is, what if you had more capacitors and were only expecting to get 10 shots. Would 500 joules be a more effective?
Make a 6-8 pound rifle version with even more batteries, and capacitors and get 30 shots at 1,000 joules
According to Wikipedia
Muzzle energy of an average 9mm bullet is 519 joules. I’m assuming this may not be a very good apples to apples comparison, but help us non physics folk out a bit.
That’s assuming perfect efficiency, i.e. all 100 joules stored in the capacitor are delivered to the target. My semi-WAG is that this setup is almost certainly less than 10% efficient, and likely much lower than that. Just the fact that in needs a minute to cool between shots implies that a huge fraction of that energy is lost as heat.
So, again as a WAG, anything handheld would deliver only a few joules at best.
There ARE military lasers in development, but they’re mounted on bigass planes and trailers. And even then they’re not really used as a direct weapon, but instead shoot down missiles or mortar shells. This scary looking laser rifle can… temporarily blind people.
Lasers in general are horribly inefficient. From what I understand, even 10% efficiency would be amazing.
CO2 lasers can be 30% efficient, and VCSELs can be 50% efficient, but YAG lasers like in the OP have pretty miserable efficiency.
Well, it would be pretty handy if you were attacked by a horde of balloon animals. And there is at least one doperwho is kept awake nights by the prospect.
Yes, but only with the power throughput of a really bright incandescent bulb; enough to burn the upper layer of dermis at close range, but not effective at longer ranges.
For an effective high energy anti-personnel laser, you would need it to be at a frequency at which air is almost completely transparent but that flesh and typical integruments will absorb readily. You also need a high instantaneous power throughput–on the order of tens or hundreds of megawatts–in order to obtain sufficient energy delivery in a few tens of milliseconds to result in energetic decomposition of tissue (i.e. it boils and explodes–yick). Realistically, directed energy weapons are most useful for blinding and pain induction, and are likely to remain so for the foreseeable future.
Stranger
We’ve had those since '95! About as much sci-fi usefulness as the OP’s laser, though…
If you really wanted a sci-fi style weapon that played around with capacitors, a coilgun would be the way to go (basically a device which uses an electromagnet to accelerate a magnetic projectile). Not that they’re very efficent either.
Yes but as soon as we apply a field, we couple to a state, it is radiatively coupled to the ground state. I figure we can extract at least ten to the twenty-first photons per cubic centimeter which will give one kilojoule per cubic centimeter at 600 nanometers, or, one megajoule per liter.