A laser that is powerful enough to hurt a human target (especially a human target with body armor) is going to be powerful enough that it'll be ionizing the air to some degree. It'll be like a lightning bolt, there'll be flashes of light and sharp cracking sounds. That's also ignoring the fact that the random bits of terrain that the laser is hitting will also be exploding. Someone under "suppressing fire" from a laser weapon would be quite aware of the fact.
All that said, the successful laser weapons right now seem to all be anti drone/aircraft and they are typically using tracked CW (not pulsed) lasers with heating over time to avoid atmospheric lensing. Lots of challenges to overcome in getting pulsed energy a long way through air.
I was wondering if we'd see pulsed lasers in anti-drone warfare.... the power supply advantages aside, focusing on just the right point in time with the pulse seems hard.
Suppressive fire is already an obselete doctrine. That's why the British army is replacing their machine guns with DMRs (Canadian military may be heading in the same direction).
Turns out turning a motherfuckers head into a fine red mist with a 7.62 tends to make everyone else around them really eager to seek cover. The threat of a well placed shot has a far better suppressing effect than the reality of a bunch of inaccurate fire.
I'd imagine a sniper is probably one of the most effective ways to suppress a group. They probably don't know where the shots are coming from, and don't know when it's safe to move again.
Having said that, I would imagine there are situations where traditional suppression is better. A hail of bullets against the side of an APC is probably terrifying even if none of them are getting through. It's going to be tough to get someone to open the hatch as the bullets are flying in. But, with designated marksmen only, you'd have to wait until the enemy tries to get out of the APC and then make a tough shot to hit them as they do.
So, basically what the USSR did ? (IIRC, machine gunners and sharpshooters carrying some semi auto scoped rifle were basically interchangeable in their doctrine, at least during WW2)
You also wont be able to see them with the naked eye. Imagine you're on patrol and your buddy drops dead and there was no sound and no visible sign except the crackling from the fire that carved a hole in his chest. War is already scary enough tyvm. Everyone is going to have to wear white or reflective gear.
If they are wearing white, all the better to see them, and use a variety of guns on them. Besides, no white is perfect, even when clean, (which won't last long) so the laser would still chew them up.
And ironically, some armies are moving away from it because they’ve realized that suppressive fire isn’t super effective in modern urban warfare. When you’re trying to “suppress” someone in a building, there’s a good chance that they can just relocate and continue firing before you have a chance to move up. Your suppressive fire is suddenly aiming at the wrong area and isn’t doing anything.
Instead, some armies (like the British armed forces) have started focusing on quality over quantity. Turns out, when every shot has a good chance to turn you to paste, you’re much more inclined to stay in cover. Even when you’re not being actively suppressed, knowing that they have a dozen scoped 7.62 rifles trained on your location means you’re hesitant to even peek your head out. They don’t need to burn through ammo to keep you suppressed, and the suppression is more effective. The occasional “hey we still have rifles aimed at you” warning shot is enough to keep them behind cover.
The purpose of suppressive fire is to force the enemy to keep their heads down, so that you can flank them or something. Unless what you're firing is harmless, it could be used to suppress.