enter image description here I miss the part where that kid screams in agony as the vaporized water in his cells cause small bits of him to violently explode.

In my story, future's warfare extensively uses laser weapons both in infantry and vechicles, as energy supply is no longer a problem. *

Information: Laser weapon types

There are two types of laser weapons, but we're only going to look at one type:

Impulse laser:

  • Mainly used by the infantry.
  • They are capable of producing short, intense laser pulses.
  • They however, have a "recharge time" : before shooting with it, the lasers created in the separated parts of the magazine must gain enough power, before getting relased.
  • They are more suitable for causing smaller explosions, via thermal shock, than heating up the target.

General attributes:

  • the line of sight must be kept between the target and the weapon until the end of the interception / attack (in impulse weapons this means: until one impulse is delivered into the target).
  • Both of them can change their spectrums.

My interests

The following list contains the things, I want to know the effects of the lasers on.


  • Covers
  • High ground
  • Collateral damage
  • Explosive objects
  • Small areas such as rooms


  • Body armor
  • Suppression tactics
  • Wounds
  • Snipers

How would these change?

  • $\begingroup$ your biggest limit will be you have to hold the laser on a person to do any serious damage, which is going to be very difficult. You may want to look at the research by Dr Bernard S. Gerstmany who has been looking at laser effects on biological tissue for years. Plasma acoustic laser flashbangs look very useful. this paper will also be relevent bmo.uni-luebeck.de/uploads/tx_wapublications/… $\endgroup$
    – John
    Commented Mar 13, 2017 at 22:22
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    $\begingroup$ The important question, which everyone seems to be ignoring, is the total energy delivered in one pulse, over what period of time (i.e. Power). Are you talking 1 megajoule? 1 gigajoule? 1 GJ in a 1 ms pulse is a terawatt, which might cause significant problems in the air at the sniper's location. At that power atmospheric effects will limit effectiveness. $\endgroup$ Commented Mar 14, 2017 at 1:02
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    $\begingroup$ It is really really hard to beat kinetic energy as a way to transfer energy to a target. I'd expect handheld railguns before lasers. $\endgroup$ Commented Mar 14, 2017 at 10:07
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    $\begingroup$ Note that laser weapons are already a risk to eyes: en.wikipedia.org/wiki/Protocol_on_Blinding_Laser_Weapons If a laser weapon was nominally designed to powerful enough to cut though human flesh, it is probably also powerful enough to "accidentally" blind a group of hostiles. $\endgroup$
    – gmatht
    Commented Mar 14, 2017 at 10:40
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    $\begingroup$ @gmatht They not cut, they explode bits of the target. $\endgroup$ Commented Mar 14, 2017 at 10:44

7 Answers 7


It seems to me that your future infantrymen will have access to Pulse Energy Projectile (PEP) lasers. If so, let's examine how these weapons would be deployed, employed, their effects, and their limitations. All of these will have effects on your primary questions.

Energy source aside - and unless your universe has some wonderous, handwavium metamaterials - Directed Energy Weapons like the PEP are generally heavy and bulky. This is because it requires a lot more components for it to generate a shot than current technology projectile weapons (we're not talking about miniature mass accelerator a la Mass Effect here). As such, even at the infantry level, these weapons will either be mounted on tripods to be carried around by its crew (hence the moniker 'crew-served weapons') or mounted on vehicles.

Only the PHaSR (Personnel Halting and Stimulation Response Rifle developed by the USAF; yes they actually called it that because of course) is somewhat man-portable, and that's a non-lethal, non-PEP device.

So for your PEP, I think the most realistic way it would be deployed is at the Platoon level as a specialized support weapon, either by a crew on a tripod, or mounted on vehicles. Everyone else will still use projectile weapons (advanced ones, of course, but essentially the rifles and machine guns we have today).

Onto your questions.

The effects of your PEP on the battlespace.

1. Cover

According to the literature I read, the PEP 'involves the emission of an invisible laser pulse which, upon contact with the target, ablates the surface and creates a small amount of exploding plasma.' (this is per Wikipedia, so keep that in mind I guess). While current technology PEPs are meant to be non-lethal, it's easy to see that if you scale this up, you can use PEPs to disable and/or destroy all manner of things that can be disabled and/or destroyed through exploding plasma. This includes vehicles (as they are currently looking at developing a counter-UAV PEP), buildings, etc.

Basically, the PEP is a very fast, long-range weapon that fires explosive projectiles without the kinetic energy transfer at the target. So if you fire a PEP at people hiding behind, say, a brick wall, well the wall will explode like its hit by - say - a 30mm shell (this is pure conjecture, by the way. I failed to locate sufficient data on how powerful the PEP plasma explosions are). The PEP projectile will not, of course, penetrate the wall, but shrapnel from the wall exploding might ruin their day, so it balances out.

The advantages of this system are that the projectiles travel at the speed of light; the PEP gunner no longer has to incorporate a lead to his aiming solutions for moving targets. The projectiles also travel in a straight line over long distances. Current technology PEP is effective up to 2km. This means that there is no ballistic drop for the gunner to compute and offset to as well. Basically, within its effective range, you can hit what you are aiming at almost instantaneously with an explosive projectile. That's an attractive thing for grunts.

Edited to add: The PEP is also an excellent point air defense system against missiles and low-flying aircraft. The PEP's advantages outlined in the paragraph above makes it an ideal system of choice - especially coupled with an automatic/autonomous target tracking and engagement guidence system like the AEGIS in US Navy ships.

There are several disadvantages as well: Laser Pulses can be dissipated through smoke/fog. Adversary forces will develop special counter-laser smoke grenades (say, containing particulates that reflect and/or disrupt the pulses) that their infantry can deploy to basically negate the effects of your weapon on target. Unlike physical projectiles which can punch through the smoke like nobody's business, that PEP projectile will just stop at the smoke. Funny thing about war is, the countermeasure is almost always cheaper than the systems they are designed to counter. So your PEP crew served might cost you USD 1.5 million per unit, while that smoke grenade probably costs the adversary USD 150 a pop. That's a bargain. Grunts love that too.

They are also heavy and bulky. A PEP team would consist of a gunner, an assistant gunner to set up and load the weapon, and an ammunition man to carry extra batteries, ammunition (whatever your PEP uses for ammo), etc. If they move, the gunner will hump the PEP gun, the a-gunner will hump the tripod, the ammo guy will hump his rucksack. Add to their loads their armor, personal weapons, supplies, etc. That is not a happy team. That is also not a fast team.

2. High ground

Well, since there are no ballistic calculations necessary for the PEP, then the high ground will have no effects on the PEP - other than if you're stupid enough to silhouette yourself on the crest of a hill, some guy with a PEP 2km away might take a potshot at you.

3. Collateral Damage

The PEP is highly accurate. You hit what you are aiming at. While the nature of the explosion can potentially cause collateral damage (exploding walls or vehicles, you know), the chances of it hitting something the gunner isn't aiming at is negligible at best.

This means that if you have to talk to the village elder to apologize about that goat that your PEP laser exploded, then your gunner was aiming at the goat.

4. Explosive Objects

I'd imagine that since the PEP creates exploding plasma on the target, then if the target is explosive, it would explode.

5. Small enclosed area

Well, two ways to see this. One, unlike traditional explosive projectiles, the PEP projectile itself does not generate fragments. So firing a PEP projectile into a room through a window, for instance, will just cause the PEP projectile to generate exploding plasma at whatever wall, object, or person it hits. The effect on the room is dependent on what object it hits. If it hits your buddy, you'd probably be covered in blood. You'd be unhappy, of course, but you'll generally be fine. On the other hand, there is that secondary effect. You fire a PEP projectile into the room, aiming for the back wall. When it hits that wall, it explodes, taking chunks of the wall with it, probably showering the occupants of the room with sharp brick fragments. The level of dismay and anger directed at you by the occupants of that room is directly proportional to the level of protection/armor they were wearing at the time.

The Effects of the PEP on Soldiers

As we have established above, the PEP is a support weapon. A highly specialized support weapon among other support weapons in the company. Remember: the PEP fires straight. This means that you can't use it for indirect support. It also doesn't have any kinetic energy, you can't use it to punch through walls or armor. It will, however, ablate armor and create plasma explosions, which you can use to disable or destroy vehicles, walls, etc. Combined with its lightspeed projectile and flat trajectory, the PEP is a pretty decent support weapon.

However, to gauge its effect on infantry equipment and tactics, several things must be considered.

1. Armor.

Here's how you design infantry armor: You figure out what the most casualty-inducing weapon on the battlefield is, then you design armor that lowers the risk to your infantry to acceptable levels. Note that I did not say 'protects your infantry against this threat.' That is because this is impossible to do (unless we're talking about HALO/WH40K level power armors here).

Armor has to balance protection and mobility. Safety and comfort. The more comfortable your guys are, the longer they are combat effective. Add mobility, reduce protection and vice versa. Up to as recently as the late 90s, artillery is still the number one infantry killer. As such infantry armor up to the 90s was designed primarily against this threat (see the PASGT system for US Forces, for instance).

It is only when the US started to get into all these fights with guys who generally only have small arms and not a lot of artillery that the focus of armor shifted, somewhat, to defeat direct fire ballistic threats (with the development of the BALCS/SPEAR system for SOF troops, that trickled down to GPF troops later on for instance. And the SAPI/ESAPI ballistic plates of today).

Back to your question, having established that the PEP laser is a specialized support weapon, and, due to its limitations, most other weapons are still ballistic in nature (from bullets to artillery shells), then the armor your troops wear will be designed to defeat those threats. A combination of soft armor to defeat fragments and pistol caliber bullets, and hard armor plates to defeat rifle rounds. So, no change there.

There will be individual, vehicular, and area counter-laser systems, though, such as the smoke dispenser/grenade we discussed earlier. Or maybe some reflective panel add-ons to vehicle armor.

2. Suppression tactics.

This is where the PEP's rate of fire comes into play. You don't have to have a fully automatic system to suppress. You just need something that can fire accurately enough (no problems for the PEP), and quick enough to render the enemy combat ineffective within its beaten zone. If you can fire PEP lasers fast enough to keep the enemy from going anywhere and/or doing anything effective to you, then you're suppressing him. If not, then you're not. In any case, suppressing an enemy with direct fire weapons (which is what the PEP is), is pretty much that. It's really quite similar with suppressing the enemy with your carbine. Except that the PEP generates plasma explosions on the enemy's cover. Probably negating it after a while like hitting them with explosive projectiles.

The enemy will try to suppress your PEP crews like they would your other support weapons too. So, again, not a whole lot of difference.

3. Wounds

The PEP wounds by a pressure wave that stuns the target and knocks them off their feet, and electromagnetic radiation that affects nerve cells causing a painful sensation. (again, Wikipedia). You scale this enough, then I suppose you have overpressure wounds and burns on human targets.

4. Snipers

Can the PEP be a sniping weapon? Well, yes. It hits stuff it's aimed at 2km away, that's precise enough to be used to snipe folks. Is it practical? No. It's a support weapon. This is not to say that no one has ever sniped with support weapons before. As we discussed, it is heavy and cumbersome. So no sniping PEPs, at least none that was designed to do specifically that.

On the other hand, PEP crews are prime sniper targets - as support weapon crews generally are. Support weapons are force multipliers. Taking out its crew at critical points in a battle may very well change the course of the fight.

So TL;DR: Your PEP is a specialized support weapon because it's not practical enough to be man-portable, and it is inadvisable to replace the versatility and simplicity of projectile weapons on the battlefield.


Effect of laser weaponry upon:


By this, I assume the conventional taking cover tactic to avoid or stop incoming small arms projectiles. You have not specified how powerful your infantry laser weapons are and what are their capabilities for melting or boiling away metals and rock. I am inclined to assume that taking cover behind buildings and rocks would still provide pretty much the same level of protection as it does now. However, taking cover behind a tree would be a bad idea as exploding out some parts of the thick branches overhead would result in the branches breaking and falling on the person taking refuge under them.

Collateral damage

What do you mean what impact would laser weapons have on collateral damage? Shooting your own team mates isn't fun, no matter you shoot them with rocks, bullets, cannonballs or laser beams!

Explosive objects

Explosive compounds are already not stored in barrels, stacked by the walls, outdoors, as depicted in movies and video games. You might employ a quick tactic tough. In the absence of remote controlled explosive devices, you could just place a grenade near the target zone and shoot it with the laser from far. It will get you the explosion you desired, even without a proper remote controlled explosive device.

Small areas such as rooms

Rooms will continue to remain rooms (I guess?). No laser weapons (or any weapons for that case) are known to convert rooms into something else. How safe rooms would be, depends on whether your laser weapons have the ability to destroy a major portion of a wall with a few laser shots or not. Even without laser weaponry, you could easily summon the demons of hell on the inhabitants of a small room with a vehicle mounted machinegun. A few RPGs would do the trick, too.

Body Armor

Will be rendered useless. Considering that your weapon shoots a light beam, you can easily shoot very precisely on your target. Body armor does not cover the face or the neck, so just take a couple seconds to aim for the face or neck, and shoot.


Will continue to be debilitating and painful. Even getting shot with a normal firearm (bullets) can be easily fatal. Getting hit by a laser beam on the leg or the arm will perhaps be more painful and debilitating than a bullet wound though. Something like getting shot by a machinegun round. It could end up severing the limb.


Will be much more successful, considering that you wouldn't have to count factors such as wind speed, coriolis effect, elevation and distance. You only have to aim and shoot. A fairly good sniper would have a 90% success rate while a good one will easily have a 100% success rate for all his shots.

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    $\begingroup$ Fog machines are now a viable defense system; sufficient fog would break up the lasers AND make an awesome light show. $\endgroup$
    – CaM
    Commented Mar 13, 2017 at 20:55
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    $\begingroup$ You are not going to be any more accurate with a laser than most modern firearms not at medium or close range. modern firearms are incredibly precise, the ability of the person to aim is the limiting factor. $\endgroup$
    – John
    Commented Mar 13, 2017 at 22:11
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    $\begingroup$ the recoil of most modern firearms don't make it to the person until after the bullet has left the barrel, lasers might help with "automatic" fire but not much else. your limiting factor is still the person trying to line up the shot on the fly. $\endgroup$
    – John
    Commented Mar 13, 2017 at 22:33
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    $\begingroup$ Even if modern weapons have reduced recoil, the vibration of the cannon because of the explosion and the bullet moving through it at Mach 3 cannot be avoided. Laser guns would be more precise, although I can't calculate how much so. $\endgroup$
    – Rekesoft
    Commented Mar 14, 2017 at 8:17
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    $\begingroup$ @inappropriateCode: depends on how localized the exploding flesh is. Since a weapon usually is designed to cause deadly damage, it has to deliver enough energy to ensure that it isn’t consumed by the surface only. If, however, you try to develop a non-lethal laser weapon, you might experience your burned enemies to become angry instead of giving up… $\endgroup$
    – Holger
    Commented Mar 14, 2017 at 10:35

Covers: Laser weapons are most effective against optics (biological or electronic) and living tissue (because it contains water that explodes upon being heated). Other things can be also destroyed by heating. Anything that is resistant to heating and melting (such as earth) will provide very good cover. Laser travels in a straight line, obviously. Your infantry will still need mortars and grenades to be tossed over cover. Fog, smoke, and dust will also provide very good cover and will be extensively used.

High ground: In modern warfare, this is less important since your infantry probably won't be bayonet charging uphill. Still gives you a better view if you do not have drones overhead.

Collateral damage: Since the "projectile" travels instantly (well, at the speed of light), you are only hitting the thing in your reticle.

Explosive objects: Can easily be made to explode with the laser, very vulnerable.

Small areas such as rooms: Depends on how small you can make the laser rifle. Also, your soldiers will not want to be waiting for the rifle to recharge with an enemy 3 meters in front of them. They would probably have their conventional firearm drawn in close quarters. Hand grenades remain the workhorse for clearing rooms.

Body armor: Eye protection will be of supreme importance. A high powered laser shot to the eyes will permanently blind and instantly incapacitate. Laser reflective materials are available and will be used on body armor. Perhaps something akin to the smoke grenades that tanks use for cover.

Suppression tactics: Since the "projectiles" are invisible and make no noise, and your version of the laser rifle seems to have a horrible rate of fire, you'll probably have to use something else for suppressive fire.

Wounds: No exit wounds. Horrible burns. Blindness.

Snipers: Laser rifles probably not well suited for this application at very long ranges due to blooming and dissipation but if with your technology you can miniaturize something that the US Navy is using to an infantry size weapon, there are advantages: Not effected by wind or gravity, instant hit, no muzzle flash. At mid-range, snipers will probably use your version of the sniper rifle but switch to a projectile weapon for long range.

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    $\begingroup$ you might also see use of large mirrored panels like these. camouflage and defense in one. i.ytimg.com/vi/W_uE9mtFRc4/hqdefault.jpg and these s-media-cache-ak0.pinimg.com/originals/bf/47/20/… Niven's second law, never fire a lazer at a mirror. $\endgroup$
    – John
    Commented Mar 13, 2017 at 22:02
  • $\begingroup$ @John Though do note that the mirror will likely be destroyed as well. Even the best mirrors we have (that can be used outside of a precisely controlled environment) will absorb enough energy of the incident beam to stop being mirrors, and possibly fracture and/or melt. How much damage this means exactly is hard to guess, of course, but you can't expect the laser to bounce back on the same trajectory either - that would be rather lucky. Mirrors can be just as dangerous to the defenders as the attackers, as they make stray shots much more random. $\endgroup$
    – Luaan
    Commented Mar 14, 2017 at 11:54
  • $\begingroup$ not entirely random, a laser is not going to reflect perpendicular to the incoming fire. Plus the mirrors in question are designed to reflect the light down, that is how they work as camouflage. the mirror will block several shots as long as they don't hit the same place. enough for that single rush from cover, or protect a sniper from stray shots. $\endgroup$
    – John
    Commented Mar 14, 2017 at 15:13
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    $\begingroup$ I really wonder is simple oak paneling might work as well, the chinese used it for reentry shielding because it has such amazingly low thermal conductive and makes great ablative armor. It would certainly make body armor lighter. newscientist.com/article/mg14619738-300-space-oddities $\endgroup$
    – John
    Commented Mar 14, 2017 at 15:27

On collateral damage, poor civilians. Laser beams will be invisible except the target itself will have a small dot. This means it's impossible to see a laser fight taking place except when looking at the targets.

This makes it hard for bystanders to know what's happening. Any beam good enough to kill a person will absolutely completely fry your eyes. So imagine fighting in an urban environment. Hit a metal street light post, a window, the side mirror on a car or motorcycle. The laser will reflect in unexpected ways. Bystanders will be blinded.

Your soldiers will obviously wear protective goggles but even those need to be calibrated to the right frequency. Blocking all will simply make them to dark to see through.

  • $\begingroup$ There probably is going to be noise, at least - the weapons themselves can be quite noisy (we're talking about a very high-powered laser here, with a local power supply), the hits will certainly be noisy (especially hitting flesh and other water-containing materials), and depending on the frequency and power, even the beam itself might interact with the atmosphere enough to produce lots of noise and even light. But stray shots and chance reflections will probably be even more dangerous than with projectiles, yeah. $\endgroup$
    – Luaan
    Commented Mar 14, 2017 at 11:58

Laser would differ from projectile weapon in one aspect only - speed of delivery. While bullet would spend travelling whole second to the target a kilometere away, the laser gets there immediately. As soon as there is a line of sight between an attacker and target, the target becomes a sitting duck. That is not because the target is not fast enough but because of Einstein.

Attack by means of projectile could be countered, modern tanks shoot back at the incoming missiles, aircraft may maneuver or shoot back.

We could divide the attack into two phases - targeting (spot the enemy, make decision to engage, pull the trigger) and deployment (hit the target). The second phase gets zeroed out when laser is used.

That leaves us with the possility to optimize the speed of targeting and decision-making. Which again means that in high-tech warfare it will not be human pulling the trigger. The battle will probably play out in the course of milliseconds and the quality of algorithms will have important role.


There is one big other factor involved here.

Does Thermally super-conducting material exist? If so is it feasible to make armour out of it? (Weight/Cost)

If so, any hand-held laser is likely to be useless, since with a thin thermal superconducting layer across the target, you will cause the majority of the affect of the beam/pulse to spread across the target. Only the very biggest weapons would be able to cause the normal plasma affect, the rest of the heat would spread across the entirety of the material too quickly for it to heat up to plasma temperatures.

The 2nd major factor (other than the weapon tech itself) will be reflective materials, the major problem with energy weapons are that most forms of energy can be effectively reflected or dispersed with much more ease than a projectile round can. Laser weapons are only effective if the targets struck can't reflect the majority of the beam.


One thing that I have is: it's a laser and you think with infantry.

Let me get one thing straight. It's a friggin laser! Laser range is far superior to be used by infantry. Because infantry have human eyes and they are pretty bad compared to laser.

So with introduction of a laser you make infantry obsolete. You just combine laser with thermal/movement/shape recognition and you can start Skynet.

You shift war/battles from close combat to long distance robot skirmishes. That's what people wanted from the start. To kill others from as far as possible with lowering the chance to die to zero.

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    $\begingroup$ Unfortunately, as many other answers said: there's an easy way to protect against lasers with specialized smoke grenades and lasers would dissipate in the atmosphere over long enough distances and we're "limited "to the horizon. $\endgroup$ Commented Mar 14, 2017 at 9:57
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    $\begingroup$ You still think with modern guns. Smoke screen? With lasers you would need to cover your "objects" 24/7. Horizon? With robots? Ever heard of drones? Atmosphere have impact on laser aperture over 140 km. Almost 100 miles. Modern howitzers have range of 50 km. Also laser in CC is useless. Because this is where you can use smoke screens and in interiors you could have antilaser atmosphere. $\endgroup$ Commented Mar 14, 2017 at 10:07
  • $\begingroup$ Yes. Yes. vehicles are outfitted with them, but that's for another question. Lasers would be good for stealthy sharpshooters and for anything else there's grenade. $\endgroup$ Commented Mar 14, 2017 at 10:17
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    $\begingroup$ " To kill others from as far as possible with lowering the chance to die to zero." - The problem being, both sides want that, which means none of them get it. $\endgroup$
    – Peter
    Commented Mar 14, 2017 at 11:25
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    $\begingroup$ Actually projectiles have a longer range than lasers as they can curve with gravity. Lasers also have major problems at long range with thermal blooming and atmospheric absorption/deflection which can all cause the beam to miss.... let alone more extreme conditions. $\endgroup$
    – Drenzul
    Commented Mar 14, 2017 at 15:41

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