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What I'm talking about is a gun that shoots red laser beams at the speed of light in pulses in an equivalent of semiautomatic fire, delivering electromagnetic damage to an enemy that melts through his armor and slices through body parts while making a pew pew sound of some type? Something that makes cauterized holes and slices through the target, plus or minus lighting nearby tissue/clothes on fire.

Think blaster from Star Wars, if the beam traveled at the speed of light and not a crossbow bolt, but otherwise behaving as a blaster does in all other respects. Is this possible, unlikely or not?

Cyn
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Charlotte Wolery
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  • if you turn a light off and on, can you make out the line of light that comes out of the bulb, pushes the darkness back, and lights up the room? of course not! Remember, speed of light is 300'000 km/second and would not be in your view for much more than a couple nanoseconds. – Twelfth Aug 19 '16 at 19:46
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    I have observed and/or executed the operation of a flashlight, a laser pointer, a laser CNC machine. and a particle accelerator. Not one of them made a pew pew noise. I get it though, I was also disappointed. – cobaltduck Aug 19 '16 at 20:12
  • Not quite a "pew pew", but high power electrolasers can produce a sonic boom – Kys Aug 19 '16 at 20:18
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    Star Wars blasters do not fire lasers, instead they fire plasma charges. – Cem Kalyoncu Aug 19 '16 at 20:52
  • Cauterization happens over time. 3rd degree wounds are usually open wounds that bleed, the cells and bloodvessles nearby burst from the boiling blood and liquids which can even flash-evaporate in an explosion-like manner, the debris of which can also cause burning wounds if the weapon is hot enough. For a medical procedure they used an electrical cutter on me, this bled a lot. To cauterize the wound they dialed the electrical cutter way down and applied this much lower temperature over a time to the wound. Lasers, lightsabers and plasma bolts in scify should not cauterize. – Demigan Feb 04 '19 at 16:41

6 Answers6

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Man portable laser weapons and sidearms are not going happen soon at our current level of technology, mostly because the energy density of portable power sources is too low, and the heat rejection issues of lasers (especially visible light lasers) is pretty high (something like 20% of the input energy is converted to laser light). Even Free Electron Lasers with a theoretical "wall plug" efficiency of 65% would have issues, especially since an electron beam moving at close to the speed of light would be a source of pretty intense radiation.

There is a reason laser weapons are currently designed for use on ships, aircraft and large ground vehicles. More on the mechanics of laser weapons on the Atomic Rockets page.

As for sound effects, a pulse laser (which is what you are describing) would actually sound much like a current semiautomatic rifle or machine gun. Ne "pew pew" but rather "crack-crack-crack".

The reasons is the same as the clap of thunder accompanying a lightning bolt. The energetic laser beam causes the air to rapidly expand and clear the laser channel. Once the laser beam stops, air rushes back into the vacant space, creating a miniature clap of thunder. Since the laser pulse is moving at the speed of light, there is still a finite space the beam fills as the laser pulses, so there will be a gap for air to smash back into.

As for the mechanisms of damage from a laser weapon, Atomic Rockets has pages devoted to that as well (although the general thrust of that section is massive megawatt+ weapons for spaceships). The principles are the same, however, and by filling in the appropriate numbers, you can calculate the potential damage your laser weapon can cause, range and other important information.

Now the theoretical workaround for a man portable laser weapon is going to sound strange; use chemical energy stored in disposable cartridges. Each cartridge is pushed into a chamber where the energy is rapidly released. The hot gasses pass through a MHD generator, and the electrical energy is converted into laser energy while the empty cartridge is ejected and a fresh one inserted.

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Of course, you could make things simple and just have the chemical energy drive a projectile directly...

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Thucydides
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Pew-Pew sound would definitely not come from the laser beam itself - light doesn't make any discernible sound. I could see you making it an artifact of the power rapidly charging and discharging, though it's not necessary for the device to function. Typically solid state electronics are pretty silent.

As mentioned in a comment, light moves way too fast for you to see. Assuming you could shove that much electrical power in a blaster-sized package (not possible with modern technology), you might have something slightly close. Some differences includes that there would be no recoil to the shot, and no explosive impact - it would burn the target, and not much else. Also, even the most powerful modern lasers take time to put a hole in a target - a sustained beam, not a gun-like shot in a single instant.

automaton
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  • And it's the wrong kind of energy. If you drop the frequency of light to the "audible frequency spectrum" (e.g., 5Khz), you're still dealing with electro-magnetic energy, not sound waves. A radio can broadcast with a base frequency of 5Khz, but you can't hear it. Electromagnetics do not push air. – JBH Sep 06 '17 at 16:01
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I know that this type of weapon is not a laser, and probably not exactly what you think, but there is a theoretical weapon explained in this video called Plasma Railgun. Basically, it shoots plasma "bubbles" with electromagnetic fields that can reach speeds of 200 km/s and higher temperatures than the sun.

It could be visible for the eye (200 km/s is REALLY fast), but it's not a laser, I don't know if make Pew Pew sounds, but I really hope this helps you.

Gryphon
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Fulano
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Visible component

Several people have commented that light travels too fast to see it travelling in bursts.

Here's how you can overcome that and produce any apparent speed from zero to C. The gun fires pulses of say a metre in length in very rapid succession. Thus the pulses overlay each other. There is a critical level of overlay that causes the air to ionise. It is the maximally overlaid portion that travels at visible speeds. (I'll add the maths here when I have time).

The main problem is that you want red. Air fluoresces in what is called electric blue. https://en.wikipedia.org/wiki/Ionized-air_glow

You could use overlaid bursts of a red laser without having to cause ionisation. The apparent slow movement of the beam would be caused by an animation effect of rapidly repeating pulses combined with persistence of vision. However there would have to be sufficient dust in the air for it to be visible from the side. Maybe the gun could project a cloud of powder or smoke for some unfathomable reason. Maybe the anti-hero has bad dandruff.

Pew pew component

This is pretty easy. You amplitude modulate the pulses. As they pass the listener and the air is distorted you get the characteristic Doppler effect. Only an observer at the side would notice the pitch change. For the shooter and the victim the pitch would be constant but the volume would still vary.

Mach diamonds

This is another possibility that doesn't use lasers. I'll have to flesh this out later.

Mach diamonds video https://youtu.be/kEw2msVaVy0?t=7

chasly - supports Monica
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Closest existing thing I can think of to your answer is a magnetron gun... You mentioned electromagnetic and laser as the same thing. They are not at all. You should touch up on some scientific articles regarding this, it's quite interesting. Even in a magnetron gun you can not see the radio waves going through the air (it is a HERF, high energy radio frequency), unless you covered it in flammable gas... :/. Also pew pew sounds don't really exist in this kind of thing unless you are slowly deflating a balloon with it. :)

Ember
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Hello From the Future!

(This answer purely deals with seeing and hearing a beam, and assumes power supply questions and the like are non-issues.)

I don't know why WBSE showed linked me to this question again after so many years, but under the right conditions lasers may indeed make sounds frequently associated with sci-fi depictions of them. Naturally, a shorter dwell time on a given surface would create a shorter sound than the following sources.

This video of laser rust removal gives an excellent example of the variety of tones lasers may make when interacting with certain surfaces. Thus the device producing the beam itself is fairly silent, but the sound is produced by the beam interacting with its target. As a bonus, this video shows how a beam may be clearly visible when moving through a cloud of the very material it vaporized. A dusty or hazy environment would increase visibility significantly.

I can't be certain, but the latter video appears to have audio filtering applied to highlight certain tones. In the same way, one's chances of hearing this noise would be (perhaps accidentally) improved for anyone wearing certain electronic hearing protection that implements the audio equivalent of a high pass filter. Such hearing protection is common in military, industrial, and aviation contexts.

A laser won't always be visible and make pew-pew-zap noises, but it is certainly plausible under the right conditions.

automaton
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