Chinese Laser AK-47: Myth Or Reality? | Hackaday

2023-02-19 02:41:49 By : Ms. June Qian

Chinese company ZKZM Laser has produced the ZKZM-500 laser assault rifle which people are calling the Chinese AK-47 because of its similar size, weighing in at three kilos (6.6 lbs). Claims of its capabilities, however, are being disputed.

The South China Morning Post writes that the company claims the laser to: 3waves Lazer Hair Removal

Chinese Laser AK-47: Myth Or Reality? | Hackaday

Burning things with lasers is nothing new but the disputes are mostly based around such a small laser being effective at an 800 meter range. To be fair, while the 800 meter range claim is everywhere, the Post writes that the company brochure says the range is 500 meters (0.3 miles), still quite a long distance.

[styropyro], a YouTuber with a lot of experience with lasers has done an analysis, starting by deducing a wavelength of around 2000 nanometers. He finds that at 800 meters the beam would have dispersed to a diameter of 26 cm (10 inches) and produce 53 W over that area. (EDIT: The 53 W is how much sunlight would produce for that area. In the video he carries the calculations further to work out the minimum power needed, ignoring losses, to light the cotton on fire, 645 W.) For 500 meters, using the same formula we calculate that the dispersion would be a diameter of 16 cm (6 inches) with 500 W spread over that area, which would get uncomfortable very fast, think of half a square meter of sunlight focused down to a circle of that diameter. (EDIT: Again, this it 500 W for sunlight, the laser produces more.) His video doesn’t include enough detail for us to replicate the remainder of the calculations so we’ll just have to go with the 800 meter claim. See the video below for his full analysis. If anyone else has any experience that’ll either support or dispute the claims then please share it with us in the comments.

After all the disputes against their claim, the Chinese company did produce a video firing the laser from a shorter distance. Check it out on this page by the post.

While waiting to see how much truth there is to the Chinese company’s claims we can sit back and enjoy [styropyro’s] home-brew high power ruby laser, both his build and him doing some serious damage with it.

Oh, and don’t try this at home. It’s probably in violation of the Geneva Convention on Certain Conventional Weapons in addition to common sense.

Mirror clothes are the new camo :-D

Tin foil hats for everyone!

Meet Mr. corner reflector, where are your laser gods now?

Swarovski is the new style for the discerning block-block anarchist.

I don’t think the Geneva Convention applies to anything other than warfare between signatory state actors.

Don’t worry, I’m sure we can print you some castanets to “see” with … :-)

Or as many drill instructors have said, the rules of the Geneva Convention only apply if you’re fighting or captured by the Genevans.

Good point… the North Vietnamese didn’t let the Geneva Convention apply to their prisoners.

Neither did Sodamn Insane or ISIS.

Sorry to rain on your parade, but despite the US govt’s assurance that “waterboarding” is not in breach of the Geneva convention, the Genevans have a different view. “On the basis of the 1929 convention the International Military Tribunal for the Far East (IMTFE; 1946–48) convicted 25 Japanese leaders of responsibility for war crimes and crimes against humanity, specifically including torture by waterboarding (referred to by the IMTFE as the “water treatment”).” … so all this GC whataboutery could be said to apply to both the US, and its various allies, but as has been said before, arguments about what is in breach of the Geneva convention, will probably take place long after your (eye) balls have been poached. “Nucular” WMD are also blatantly in convention of the GC, at least in part because they do not discriminate in any way between combatants and non-combatants, and indeed their primary purpose is to kill or threaten to kill large numbers of civilians but that hasn’t stopped a rush for countries to acquire them. The GC, is the second casualty of modern warfare, after “the truth”, of course. I guess the time has come to stock up on the Joo Janta 200 Super-Chromatic Peril Sensitive Sunglasses, and factor two million suncream.

Burning children with napalm is not a North Vietnamese invention though.

No, but the last I heard, all napalm has been removed from the U.S. military inventory.

Yup! Soon as they worked out it was *wrong* to set fire to civilians from aeroplanes, away went the napalm.

“No, but the last I heard, all napalm has been removed from the U.S. military inventory.” Replaced presumably with various thermobaric weapons, that way the civilian victims and the press both get eliminated, thus avoiding the embarrassment of incriminating photographs.

only after declaring war. I don’t think there has been a proper war since WW1.

Sounds like you haven’t read up to the chapter on the 1940s.

Or really any decade since then.

Mostly people can’t comprehend declarations of war.

For example, even when the US Congress passed a bill that spent money on a war, and explicitly said that the language they were using met the standards set out in the War Powers Act for authorizing ongoing military actions, people still blathered on and on about how they “hadn’t declared war.” Even though they had, and then in the next sentence, clarified that they had.

They just don’t use the phrase “We Declare War,” so 99% of the people who purport to care about if a proper declaration was made or not refuse to listen. And yet, no treaty ever has required any particular exact phrase to be used, or submitted in triplicate, or anything of the sort.

This has been the case in every war since the Korean War. And they ignore that the UN authorized war in that case, too, rather explicitly. Regarding WWII, they somehow miss the fact that the US and Japan both declared war on each other, very near to the time that hostilities began. And war between the US and other combatants was mutually declared shortly thereafter.

Heck, a couple decades ago the US Congress declared war on a non-state entity, a war that continues today, and most of the country can’t comprehend that war was really declared on a non-state entity. A small number of people purport to care about the implications, but few of them care enough to find out that it really happened, it was a real war declaration.

I’m getting a decent amount of comments saying that my assumption that they would follow the Geneva convention on blinding weapons is invalid, but they’d have to follow it for practical reasons. The company talks about using it in hostage situations. Even if you shoot the guy with the gun, everybody else in the room instantly goes blind, as well as anybody outside taking even the slightest reflection. Looking at the spot of a 0.5W laser on the wall can permanently damage the eyes, so how about one over 1000 times stronger?

Flashbang, not to mention the noise, and pressure wave.

If the duduced wavelength of 2000 nanometers is correct, then it’s outside the visible range. Hitting your eye with it will blind you, of course, but so will a bullet.

There is no way this would be a 2 micron laser. It would be 1 to 1.1 micron laser.

Where I used to work they had a couple of 2000 watt co2 (10.6um) laser cutters that were almost always set to 2000 watts and cutting shiny stainless or aluminum. None of the operators wore safety glasses, and even with mistakes none of them ever had eye issues.

On piercing aluminum you can feel the reflection of the laser on your face like standing in very, very bright sunlight.

Using long wavelenghts (deep IR) would bypass the geneva convention because the eye does not focus the light, so it does not result in the same blinding effect as say a green laser pointer. Of course it burns just the same, so your eyes will boil off the sockets if you get shot in the eye, but the effect is more “topical”.

Your cornea will still focus that beam into an extremely tight burning spot on your retina. The only difference is, your iris will not react to the brightness, so in effect makes it potentially worse.

No, it won’t be transmitted through the eye. Hence (for example) communications lasers at 1550nm are eyesafe.

A CO2 laser at 10um is as well, but a 100W laser is like sticking a fire on your cornea, even without transmission through the eye.

Also, the US never signed the Geneva Convention and isn’t bound by it.

They signed parts of it. They can cancel it but have to announce that 1 year in advance, and any time the party is in armed conflict does not count, so that year would last forever.

“Also, the US never signed the Geneva Convention and isn’t bound by it.”

Which of the THREE Geneva Conventions did the U.S. not sign?

Also, the guys that got waterboarded were unlawful combatants that are not covered by the convention because they were not uniformed soldiers of a nation state signatory. Actually they could be summarily executed on the battlefield for that offense.

I was under the impression the Geneva Conventions were signed by the U.S.:

Looks like they signed them all to me as noted in my other thought reference and this one:

It also doesn’t count if they don’t advertise it as a “weapon”. Laser guidance systems can easily blind a human and are used all the time, the trick is to “accidentally” sweep it over a crowd of enemies.

Then figure compliance, inspection and enforcement to the regulations???

Helps ensure your flesh remains moist after being cooked

Tuck some potatoes and onions in your hair for a delightful roast.

Hair? What is this hair of thou speakest? B^)

Lasergaming will never be the same…

They could have added a rangefinder and just focus the beam at the target…

The beam diameters I calculated were the absolute minimum obtainable at that distance for a 15mm beam diameter and 2000nm wavelength. You cannot focus it down any better than that with those specs. If you made the beam wider, then you could focus it down smaller at a distance, but the company explicitly says that their laser gun does not require focusing the laser beam to hit a target.

But you are assuming a 2um wavelength, and a multimode beam.

If this device is entirely laser diode based, 2um is unlikely.

2um would make it a Thulium wavelength (if we take your wavelength assumption), so a thulium fiber amplifier in a MOPA setup with with a picosecond seed would allow for far higher peak powers with a single mode beam.

Adaptive optics make the system even better, allowing a much smaller spot size.

If you know of a way to use adaptive optics to significantly beat the Rayleigh criterion, you need to publish it real fast.

You might want to actually read before posting.

“A more useful measure in this case is the Strehl ratio, which is the ratio of the intensity at the peak of the observed seeing disc divided by the intensity at the peak of the theoretical Airy disc, as shown in figure 61.

The Strehl ratio is often used to characterise the performance of the adaptive optics system. A Strehl ratio of 1 indicates perfect correction, yielding diffraction-limited images.”

Adaptive optics can (theoretically) get you to diffraction-limited imaging. It can’t get you beyond it.

It’s all about wavefront control. Controlling the phase of the light at the target allows control of constructive and destructive interference.

With high peak power pulses, these constructive interference patterns can allow material ablation at sizes far smaller the the Rayleigh limit, and at sizes smaller than than the wavelength of the light used.

Not without knowing the distance to target. Maybe if you’ve got some sort of adaptive optics combined with range determination.That *might* be possible, although you’d probably also need some way to actually image the spot… which gets you back to the Rayleigh criterion.

The Rayleigh limit of the imaged target is not a limit to the spot size of the wavefront controlled laser beam. The target is simply imaged as normal using an initial laser pulse to determine what phase correction is needed to compensate for air perturbations. This is akin to using a guide star in astrophotography. Here is an example-

Yeah, but then you need to be able to image the spot, which is what I said. It’s just a reverse problem – you then need large optics, which you could *kinda* do but it doesn’t really look like they’re doing. There’s no optics visible there that are large enough to resolve a spot that small at those wavelengths. Maybe if it’s shorter wavelength (and therefore iffy legal)? But even then that seems unlikely

It’s not the same as a guide star, because a guide star is received via the same optics that you’re trying to correct. Here you’re trying to correct the optics of a *transmitter* at the target, so you need a separate set of optics to measure the spot size.

You’re not imaging the spot with the (destructive) laser beam. You are gathering info from an initial laser beam (which does image to the target plane), and using the distortion data to adjust the phase of the (destructive) laser beam.

It is just like creating a hologram on the fly. You are controlling the wavefront of the beam to cause an interference pattern of your choosing at a particular focal plane, without needing to focus. The interference pattern can be a spot, a circle, or a smiley face if you like.

It’s the same math! Really! If you want to image the spot at 2 um with enough resolution to correct it, you need an aperture *bigger* than the spot. It’s just optics. You either get a huge spot at the target, or need a huge aperture camera to get the light. No free lunch.

To put math to words, a 1 micron laser out a 15 cm aperture is about a 3 cm radius spot at 400 m: (1 um)/(15 cm) times 400 m. Let’s assume you want to use optics to reduce that down to a 1 cm radius spot. So you need 1 cm resolution at 400 m in your camera to see it.

1 cm resolution at 400 m is roughly 25E-6 radians (or around 5 arcseconds). Getting 5 arcsecond resolution at 1 um requires around a *half-meter* aperture. There’s no half-meter camera on that thing. You can’t correct what you can’t see.

It’s likely to be a thermal laser, such as a cavity full of CO2 excited by an arc.

There have been plans for chemical laser weapons based on heating a shot of CO2 to high temperature, and passing the scalding hot gas through a laser cavity as it expands, where the shot of hot gas works as the gain medium for its own thermal radiation. The problem is fouling the mirrors after/during the shot because the gas would be heated up by pyrotechnics.

Another proposed version had a small radioactive pellet inside a pressurized CO2 tank – a radiothermal heater – but that has the obvious problem of cooling the thing because you can’t turn an RTG “off” by any means.

You could power a standard CO2 laser for several minutes off a good enough lithium battery. Technically it would need liquid cooling but if you don’t need a high duty cycle heat sinks and maybe a Peltier could be used.

Yeah, but the peak power will be lower and diminishes as the battery voltage drops. The point of the chemical laser is dumping loads of energy into the cavity in a short pulse.

We do sub-wavelength micro-machining with an ultra-fast laser (1035nm center wavelength) using a 2-D spatial light modulator, and it works like Ted described above. You really are creating a virtual focal plane to create constructive interference upon. You don’t even need to focus to get sub-wavelength features machined, but you need high enough fluence in the area of interest to allow you to create sufficient constructive intensity to ablate the material.

Would atmospheric thermal lensing also be an issue for a 2um laser?

Which would add a motorized zoom lens to something that is supposed to withstand “field use”… There is a good reason why most remotely controlled weapon platforms have several separate fixed magnification cameras instead of one with a zoom lens.

“The fog of war” is the best defense, or any handy smoke screen

Somehow, my highly reflective jumper now seems like a great purchase.

The soldier of the future, indistinct from a disco ball wearing a welding mask…

Microwave popcorn cluster bombs next?

Change your moniker to butterspread, and we’ll really see the humor of the situation.

How can this be of any use in a combat situation? You are revealing your exact location for two seconds and will have an incoming heading your way before your shot is over.

Quick swipe blinds a lot of enemies, before they can shoot.

At 2um wavelength, it should be fairly eye-safe, a lot of modern military-grade laser gear is shifting to these wavelengths to prevent eye damage.

Until it’d actually start burning your face, you’d be fine ;-)

It probably would not work that well in practice and after a couple of encounters the enemy would start wearing goggles and then the weapon becomes a liability.

If the enemy is anywhere near flammable materials it would be a great way to flush him out. Granted, at range, there are assuredly much better methods of starting a fire nearby.

Yeah I don’t think we’ll see this taking over from the ballistic assault rife any time soon but if it does what it claims it might make a good auxiliary weapon useful in some circumstances.

How can this be of any use in a combat situation? You are revealing your exact location for two seconds and will have an incoming heading your way before your shot is over.

The wavelength used is invisible to the human eye so you wouldn’t see where the shooter is. The only way you could tell is if the air near the shooter was filled with some particulate which absorbed and remitted the light in a visible wavelength. Not just anything will do it.

All any combatants would need to do is put on their NVGs and this gun would be as obvious as a searchlight. Or, what I presume [Daniel] was talking about is turn on a heat seeking / laser guided missile and wait for target lock. I suspect given the nature of lasers that might be harder than expected, you’d need to know where the shooter was first. Since many munitions are already laser guided by the aircraft or ground forces it’s a workable, if expensive, solution. 100kUSD to take out maybe a squad of guys giving you minor burns and melting your web gear off of you seems a bit excessive.

Ah, good point. I was thinking mark 1 eyeball only.

Target lock? The “shooter” is limited to 2 seconds per shot, and may actually be selecting targets before shooting.

If the guidance system is already powered up beam riders should lock on in that 2s window if the beam / ‘rifle’ happens to be in their field of view. I don’t know how current munitions behave when they lose the target though, whether they start spiraling in an attempt to re-acquire, self destruct out right, or continue on their path as a now-dumb-munition. If they continue on their trajectory they’d still be moderately effective against comparatively slow moving people. It still seems like overkill for a mostly annoying ‘weapon’ that at worst will blind you. Maybe once someone starts making Prism tanks a la Command & Conquer it’ll be worth it to pursue.

As stated in more thorough articles on the subject, this gun is intended for crowd control measures, such as targeting flags or other flammable objects in an effort to disperse an angry mob.

That doesn’t change the fact that the claimed effectiveness is dubious at best. Even if it does work as advertised, I don’t see it being a terribly effective combat theater weapon though.

Is this some strange kind of flag that I don’t know about that you keep completely still?

I mean, clothing, maybe, but trying to target a flag with this just seems to border on the ridiculous, unless you’re on the Moon.

Moon flags are specially designed for mechanical oscillation that mimics blowing in the wind whenever they’re moved around, so it would present the exact same challenges as an Earth flag.

That said, the laser doesn’t mind the billowing, the focus doesn’t change that much over the range of motion of the flag. Also keep in mind we’re talking about something in the area of 25cm diameter area that you’re heating. So it burns pretty easy.

It’s not the focus that matters. It’s:

1) The spot doesn’t stay at the same point on the material. 2) The angle of incidence doesn’t stay the same either, so the spot is effectively elongated.

A flag billowing is the similar to the guy with the gun waving it back and forth at a stationary target. Obviously that won’t burn anything very well. And that’s completely ignoring the increased convective cooling that you’d have as well.

When protesters get militarized.* Let the tug-of-war begin.

*With a lot of activism going AR, physical crowds isn’t as effective (occupy movement).

Yup. One needs to keep in mind that this gun is intended to be used against civilians of the soldier’s own population.

I don’t think it would take long for serious protesters to develop countermeasures to a weapon like this, there have been guides online for a while on how to counter tear gas. We’ll see protesters wearing laser safety glasses, wrapping themselves with those reflective emergency blankets perhaps and carrying water to douse any burning flags, or make them from flame retardant materials or just not bring them in the first place.

Or they can bring American flags and not care if they burn! (tongue in cheek)

The flashbang of a projectile rifle will do the same. Soldiers are taught how to calculate how far a person is from the the time the flash of the round’s fiery exit of the rifle to the sound of the bang of the explosion. So, having a laser light would actually make it harder to find tbe person firing since the sound component is severely reduced.

500W over a 6″ area works out to less than 5W per sq. in. Not even sunburnih

That 500 W is the sunlight equivalent. The actual is higher but I didn’t have the details for doing the calcs.

Why set fire on clothes, when you can apply this, to retinas on many unsuspected soldiers. What convention you say?

The same convention that says we can’t have explosive ammo for small caliber weapons…or use white phosphorous as a weapon…or use poisonous rounds…

Ah the “what you do to me, I’ll do to you” better known as the eye for an eye doctrine.

I don’t think it is really that broad, I think it just bans exploding bullets without defining what is a bullet and what is a type of larger shell. There isn’t some sort of categorical ban on exploding ammunition for specific weapon calibers. Snipers use exploding anti-armor rounds, and that has always been understood to be legal.

Ultimately, it only tries to ban the things that all sides agreed had limited military effectiveness, so there is no reason to define it; they wouldn’t have agreed to ban anything they considered useful. If they start to think it is useful again, they’ll be able to figure out which word to use.

They agreed to ban exploding bullets because they increased deaths and disability of soldiers without increasing the number of casualties; the soldiers who got hit with regular bullets were just as likely to stop fighting, so the extra injuries were without utility.

Of course for lasers, it in only the purported intent that is even involved; and blinding weapons are only banned when blinding is their sole military purpose. Even a targeting laser that also blinded soldiers would be allowed. Blinding is avoided because it is believed to be harmful to the side doing it; everybody ends up hating them.

It’s actually worse than his calculation claims, because you also need to be at normal incidence to deliver that much power (or be shooting a spherical human). Which, you’ll note, is exactly what’s going on in their tests.

Just because this completely amuses me, he’s also being way, way too *conservative*. The Stefan-Boltzmann law is the *equilibrium temperature* something reaches, while radiating as a blackbody, when exposed to incident power. It doesn’t tell you how *long* it takes to get to that temperature. (He’s also a factor of 2 off, because the object radiates on both sides of the material).

Amazingly there’s actually a calculator online to figure out how long it would take to ignite clothing (for arc flash concerns):

A cotton T-shirt, with a heat flux *5 times higher* than what he gave would take 154 seconds to ignite. It would take *9 cal/s/cm^2* to ignite a cotton T-shirt in 2 seconds. That’s ~20 kW, or 40 kJ, or 40 *megajoules* of energy storage needed for 1000 shots. So, yeah. Total bull at face value.

At deep IR frequencies, the beam would actually go through a cotton shirt, and your epidermis, and get absorbed within the body over a larger volume of flesh.

Take a 500 Watt halogen work light and cover the front glass with your hand, then turn it on for two seconds. Burns? Not much.

Yeah, my guess would be a frequency that is absorbed more my the human body.

I also wonder if there is some sort of multi source beam forming device also to change focus say relating to a range finding central beam where the outer beams can change angle to converge based on the central range finding beam that may contain other spectral target shot optimization and trajectory data.

Water is a good guess since we are mostly made of… wondering what else would be better like proteins, lipids, carbos, vitamins or minerals? Wondering what human body resonance frequency would aid in constructive interference effects also and maybe could be tuned to be optimized.

I also was wondering about what dopes could be placed on the targets to assure a higher degree of target specificity or dog and pony show casing for sales and investors.

Kind of makes me think of ghost cities and fallen over high rises over there in China. More bs than I realized.

The battery capacity checks out– a 500 watt beam for 2000 seconds means it has a ~250 watt-hour battery, and E-bike batteries that come in that capacity are about the size of this device. I’m betting if somebody shot it during combat there’d be a sizeable explosion…

That would be a 250 watt-hour battery at nearly 100% efficiency, a number that would appear about as dubious as some of their other claims. If the laser only converts 1/3 of the electrical power into light (which is still much better than the CO2 lasers I was working with a decade ago), you’d be looking at a battery that already weighs more than the claimed weight of the gun.

And that may be good news for the people/soldiers the weapon is targeting. They may be using “Chinese Battery Rating) on the power source, i.e. overly optimistic. B^)

And “Chinese power rating”, which – at least for LED devices – is often off by a factor of three. “Chinese” Lumen rating” for pocket torches is mostly way more off, claiming 2000lm for a 3W LED torch.

Good point about the laser efficiency! I love how on Hackaday you can always find someone with real experience in any topic.

Except for the proper way to hang a toilet roll.

Is it a gas laser, or a load of LED lasers banked together? There was that vandalism-paint vapouriser a few years ago on HAD, a commercial product, that had a backpack, or a little cart option, crammed full of diode lasers. Fed through a fibre into a thing-that-fires, not exactly a gun, gave a line 15cm or so long. It vapourised paint in a strip 15cm wide.

It’s the same sort of orders of magnitude as this thing, could be the same technology. I admit I don’t know if they made diode lasers in that wavelength.

With a battery operating at no more than a few volts over your diode array, you can build a fiber laser with today’s hardware that’s about 70%efficient.

No, you can’t. You can build a multi-mode fiber coupled laser diode with that efficiency though. Even pumping into a low quantum defect state, for example pumping Ytterbium at 976nm, you still only get ~60% optical to optical efficiency.

That’s news to ipg. They can sell you a fiber laser with >60% wallplug efficiency right now.

IPG can’t do that. They ignore cooling requirements in their estimates. Laser diodes in the NIR range can have 60% electrical to optical efficiency though, hence the ~60% efficiency of fiber coupled laser diodes, sans the active fiber gain media.

You DONT need to cool a laser like this. Look at the specs for the Pete of sake! 2 SECONDS firing time. If it’s 1 shot or even 10 shots every say 10 minutes, then zero cooling is needed. None. Zilch. The thermal inertia of the laser at even only a few lbs would keep the unit from overheating.

You guys keep talking like this is a cw system that’s meant to run 24/7.

No one said it was a CW system. It may be based on a mode locked thulium MOPA setup for all we know. And yes, if the duty cycle is so low as to be useless for any military application, then you could probably get away without cooling.

If all you need is to distract a bad guy, then 1 shot of 2 seconds long is all the use you need.

You are assuming it is 500W average power. It could be 500W peak power pulsed at 25MHz for a duration of 2 seconds.

It’s not the peak power that matters. It’s the average power and duration.. You’re damaging things with heat. You need to heat up and damage the target, and to do that you need energy.

Correct. Someone made an average power assumption. Depending on the application, high peak powers may be preferable. If you want target heating, you go with high average power CW. If you want cutting and ablation with minimal heating, use high peak powers. High peak powers are far easier to produce in this form factor anyway, without the ridiculous cooling requirements needed by a 500W average power laser.

NO cooling is needed for a 500w average power laser that just runs for 2 seconds. None at all.

Try it and see what happens to your expensive diode bars.

Brian, I have. Except with single emmitters. No one uses bars to pump fiber.

Look up heat capacity lasers. This isn’t new. There are applications where no active cooling off a laser makes sense. Llnl made a 10kw flashlamp pumped nd laser with no active cooling, and with good beam quality

Enough single emitters for ~500W class fiber lasers gets ridiculously expensive. The number of pump couplers alone would be ridiculous. Fiber coupled bars are more common, with 200um or 105um cores. These are then coupled using pump couplers.

Kevin, 100% of ipg fiber lasers use individual emmitters. As many other oem’s do. Bars are cheaper per watt but offer 5 or 10% the lifetime. Most high power ipg lasers are pumped with cans of 3 or 6 diodes coupled int a 105u fiber and then those are coupled into the gain medium.

IPG makes their own pump diodes and pump couplers. That’s why they get away with that. Most other manufacturers don’t do that.

I know for a fact other oem’s use single emmittets too.

High average power (CW and long pulse Q-switched) fiber lasers do use single emitters with pump couplers. Single emitters and pump couplers are useful for oscillators and preamplifiers also,. Short pulse and ultra-fast fiber lasers don’t bother using single emitters for final amplifiers.The power required is too high, and the length of gain fiber must be kept short to combat dispersion and self-phase modulation.They free-space couple the pump into the short length of gain fiber.(counter-pumped) using fiber coupled bars. Amplitude, Coherent, and Clark-MXR do it this way because it is best practice, and gives the best pulse quality. PCF or dual-clad LMA gain fiber, either way, dispersion management is a serious design concern.

Ultrafast pulsed amplifiers have no bearing in a discussion such as this.

Short pulse is the way to go in this application.

The average power assumption was made because the company here specifically said that it would light things on fire. You light things on fire by heating them up, hence, average power.

yes, i get it. it’s a “Chinese company” ..not just a regular company but a “Chinese” one. there’s no need to tell me twice.

China does have an appaling human rights record, so it’s not surprising this comes from them.

If this were American, they’d do it on the sly, sell it to foreign governments for use on foreign civilians, or make up some bogeyman to use it against. Those uncontrollable PCP-addled supervillains who regularly lift cars over their head and snap lamp posts over their knees. Or, y’know… THOSE people. You know the ones. I’m not gonna SAY it, but I don’t have to. You know the ones. No use talking to ’em.

Greenaum – You mean like the Yank’s wrestler/thespian JOHN CENA in a car wax advert? :-)

I did not read anything about the wavelength. So it could be a much shorter wavelength, like ulraviolet, which allows a much smaller spot like infrared.

The company claims it goes through glass, and a good portion of UV is blocked by most glass (and there’s a bunch of types of glass that completely blocks UV, too).

Are you kidding me? 75 comments in just 2 hours for a chinese laser?

Please do the maths before you comment.

2000nm? Not a chance. Its just going to bog standard 1047-1064. Dont think for a second these people care if it will cause eye damage.

There is really only one eye safe wavelength commercially made and that is 1550 and those are incredibly rare at high powers. I was “playing” with a 1550 at work that would do 5W max avg at 100-200khz rep rate and it was a raman beast, the company that designed and made it went under a couple years ago. The thing was massive, one rack unit for the fiber laser that pumped it, another for the amp, and another that contained the control computer and seeder.

CO2 lasers are fairly eye safe

“eye safe” in the context of only burning the lens of your eye (requiring a transplant to correct), rather than burning the retina (not fixable).

Not at the powers that most of them run at, especially anything powerful enough to do what they are claiming. Sure your retina will be fine, but the rest of your eye will be a mess.

The convention on blinding weapons applies to lasers DESIGNED to blind. Like low average power q switched lasers. There is a big difference in a laser designed to blind and one that *can* blind. The military has used plenty of lasers that CAN blind.

Where does the supposed 2um wavelength come from?

It would have to match a realistic gain medium for a powerful laser. It’s claimed to be infrared. A CO2 laser (10.6 um) is not practical in such a small space at high power, but a laser diode stack at about 800nm would be plausible. A neodymium laser (1064 nm) sounds like a realistic choice, along with ytterbium doped fibre lasers (about the same wavelength) which are increasingly dominant for both laser weapons and industrial applications.

Someone guessed at it based on nothing.

2um would be thulium, but there is no particular reason to use that wavelength.

It’s guessed based on the specs from the company – has to go through glass, has to burn skin, and then the assumption of it being a non-blinding weapon. It’s the last assumption that’s probably wrong. It’s almost certainly blinding.

But then again, at ~1 micron, that’s only a factor of 2 improvement in the spot size and so a factor of 4 decrease in the spot area. Then if you assume the paper’s 800 m claim is total crap (company doesn’t say it, after all, standard marketing speak of say it can do X, Y, and Z, but not mention that it can’t do all of them together and it’s only X/Y/Z under special conditions), and cut it down to, say, 400 m, now you’re talking about another factor of 4 decrease in spot area.

At this point you’re getting closer to sanity: now you’re talking about needing ~1.2 kW *delivered* assuming a spot size of 30 sq. cm (1 micron beam out a 15 cm aperture at 400 m is roughly a ~3 cm radius or so). That’s 5 megajoules of energy, which you can’t get in 3 kg of batteries, even if you totally ignore laser efficiency. So, OK, maybe marketing speak on the weight is bullcrap. Maybe it’s just the rifle portion that’s 3 kg. With high-end efficiency (50%) you’d be talking about ~10 MJ of energy storage needed, or 3 kWh. Which is like, a 20 kg battery pack. So, uh, not something you’d want to carry around.

But even in this magic case, where we’ve stretched things pretty hard, this would only work if you were firing at a stationary person at normal incidence to you and there was no line-of-sight attenuation. And the cotton T-shirt only *barely* ignites at the end of 2 seconds. So that means that the person doesn’t even move to look at why their shirt is getting hot.

Now, of course, what about the video that’s there? That’s easy – that’s not 400 m. It’s more like 100 m. And things go by distance squared, so that’s a factor of 16 right there: which means now you’re talking about a 75W laser, and a ~200 Wh battery pack – which is about a 5-pound battery pack. Both of which are far, far more reasonable. But again, note that in the video, you still had a stationary target at ideal orientation.

It was guessed at based on crude specifications from the company, and then elaborated on by people with a poor understanding of the operation and implementation of the device.

It really doesn’t matter. It’s a factor of 2. 1 micron vs. 2 microns doesn’t take you from “crazy” to “plausible.” It’s still nuts.

Let’s get you a wavelength-dependent estimate, though. If you just go by the “light a T-shirt in 2 seconds at 500 m” you can get a required flux (~37.5 W/square centimeter) at 500 m. A 15 cm aperture means your spot radius at 500 m is around (3 cm)*(wavelength in microns).

So now your required laser power is around (1 kW)*(wavelength in microns squared), and your required energy storage is correspondingly around (550 Wh)*(wavelength in microns squared)*(laser efficiency), and with a ‘nominal’ laser efficiency of 50%, a good ballpark would be 1 kWh*(wavelength in microns squared).

Oops: required energy storage is ~1100 Wh * (wavelength in microns squared)*(laser efficiency), or ~2 kWh*(wavelength in microns squared), assuming 50% efficiency. Forgot 2 seconds per shot.

1kw at 50% efficiency for 2 seconds is 4kj, ie a hair over one wh where are you getting kwhs from?

1000 shot capacity. I realized that I thought it said 2000 shot capacity, so again, off a factor of 2 again. So yeah, (500 Wh)*(wavelength in microns squared).

The story I saw originally said 500 shot capacity. And if we up the efficiency to bleeding edge levels, you are now at a few hundred wh, a battery of under 1kg with off the shelf technology, and possibly substantialy less using technology demonstrated in the lab (maybe not rechargable)

The South China Post story said “more than” 1000 shots at “under 2 seconds” a shot. So yeah, *maybe* you could stretch it and say 500 shots, 2 seconds, so maybe a 250-500 Wh battery, which becomes reasonable.

But again, that’s super-stretching everything to the limit, so it’s *possible* assuming it’s a massive amount of marketing speak. Which would mean it’s really only ‘useful’ at short distances and super-dangerous to people’s eyesight.

I strongly disagree. You would not need to hot these specs to have a weapon that was VERY usefull in limited circumstances. Have you seen what happens when a high power laser >kws beam interacts with flesh? I played with a 10kw fiber laser and a fat beam, roughly the size of a us quarter, ablated pork chop to a depth of maybe 1/8″ just as quick as I could turn it on and off by double clicking a mouse. 3kw is about the limit for what you can get without a mopa achiecture for single mode out of yb fiber. A few seconds of that with a good focus would sure as heck incapacitate, possibly even kill. Maybe not at 800m, but certainly from lesser, still tactically significant distances. You would have a weapon that is 100% silent, doesn’t care about wind or Target movement (so long as you can keep the spot on the target). You don’t need >1000 shots from a weapon like that. You don’t even need >100. Just carry a spare battery or three. It’s not like snipers don’t carry extra ammo..

The need for a weapon like this is low, it’s usefullness is equally low, but it could prove to be VERY usefull in limited situations. You are making far too much an argument against the idea. It is entirely possible with current technology. Will it replace the 1911 as standard issue? Of course not. It doesn’t need to…

I don’t want to cast any aspersions on the “Laser expert” [Styropyro], but, there is one LASER I suspect he has never encountered. It is possible that the PRC has developed a LIPC Laser that is man-0portable. The US Army (PICATINNY ARSENAL) has been developing the LIPC Laser since 2012. It is possible that PRC has stolen the specs for it and made it work better, or at least smaller. Ours is in a large box that can be made mobile, and is quite devastating to a target. A Dr. Pavel Polynkin of University of Arizona has been doing parallel research on the LIPC LASER since 2014. This may explain the PRC parallel research too..I’m pretty sure ZKZM will not be sharing any data about ZKZM-500 identifying it as a LIPC Laser. PRC President Xi Jinping would not be happy if they did…

This is a car at PICATINNY being hit by a LIPC beam from a distance…

Not strictly a laser weapon since that’s not what does the damage.

Ostracus – Yes a D.E.W. – it actually uses two LASERS to create a channel. It would make for a great crowd control wep if you don’t mind Marvin the Martian type devastation: (2 minutes of wry humor)

Maybe a micro plasma cannon, micro LAWS or micro Marauder type system:

HHhmmm… be creative with the projectile (plasma):

Well… the USAF as well as the NRO related agencies do tend to be modest with their and their contractors systems… even if acknowledging with strange homonyms different alien, UFO, mind control, psychic and other intelligence, space and remote sensing and transmission electromagnetic spectrum abilities systems. Looks like Shiva Star, NIF and the Marauder systems aren’t so well documented, though this one is a little… though not so portable:

Here is the video of the actual test on a roof in Xen China. Analyze it for yourself. I think a similar (but much less powerful) device can be built by cannibalizing your DVD Writer. You could pop black balloons from across the room. The power source is obviously this: “Researchers at the University of Illinois at Urbana-Champaign have developed a new lithium-ion battery technology that is 2,000 times more powerful than comparable batteries. According to the researchers, this is not simply an evolutionary step in battery tech, “It’s a new enabling technology… it breaks the normal paradigms of energy sources. It’s allowing us to do different, new things.” .jpg

Just click on the widget for it to play the video…

Would this be more effective if the target was looking down the scope of a rifle?

Isn’t it common for soldiers to encounter targets looking in their direction through optics?

It’s totally illegal according to the international rules of engagement and war to use weapons to permanently blind people. And miraculously most of the rules are actually followed, albeit not all and not all the time. And that includes against enemies that didn’t sign the treaty incidentally. And including engagements that are not officially called war.

NO IT IS NOT. It is illegal to use weapons DESIGNED to blind. You *could* blind someone with many variants of laser range finders and Target illuminators that have been fielded by many nation’s. Their use, even if it results in blindness is not illegal.

The rules of war don’t always make sense. Case in point, I have an artillary she’ll designed to disperse chemical weapons. It was NEVER filled with any chemicals. It is still a chemical weapons by the rules of war. If I bludgeon you over the head with it, I killed you with a chemical weapons.

I think it’s silly to think if the largest countries went to war any such rules would be honored. The only reason most are honored today is that smaller players fear repercussions from larger players and larger players don’t need them.

Anyways, feels like a really good anti-sniper countermeasure. Even if you assume China can’t create UV lasers, it still would be like looking at the sun through a rifle scope right?

Even with the effort the US did to vote in a person like Trump you are still wrong I think. The problem though is that the US for one does massively use experimental weapons of weapon manufacturers, and in many cases there are no rules yet for those, even if you can tell by their very nature that a decent person would hesitate to deploy them.

Such a weapon would avoid the Geneva convention by obviously having been designed to take care of the killer robots that the pentagon is absolutely and for sure NOT developing. No really, they promise! Except robots don’t wear cotton, or do they? But hey, it’ll burn nylon too surely.

China is like the worst place in the world to deploy laser weapons with all the particulates in the air

They constantly do fire lasers though, the army that is. And China is pretty big, and the pollution has a tendency to hang in places, like we saw with disastrous results in London and LA in the past.

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