[00N8]

Are you sure about that? AFAIK effective laser drone defenses are not yet widely deployed proven technology, but I don't think small beam size is a limiting factor. Getting enough power onto the target to disable it is a big challenge, but part of that is fighting the natural tendency of the beam to spread out & be attenuated by the atmosphere - not that the beam affects too small of a spot on the drone.

Having a laser that spreads out to e.g. 30cm radius at 500m is not hard to do if you need an area of effect weapon & can push enough power (ie. your laser is powerful enough, but not so intense that it ionizes the air & blocks itself). Reflections seem like a bigger problem: If the most effective defense includes guys with shotguns &/or there are a lot of unprotected personnel in the area, how do you make sure stray reflections don't end up blinding them?

[glitchc]

The point is that a focused laser will put a hole through the drone, much like an armor piercing round, but that is often insufficient to disable the drone. A larger ballistic projectile (think a solid shell or a rock) is much more effective. Alternative energy weapons based on microwaves and SPL also work well.

[Oarch]

Presumably hitting any rotor, even a small amount, could be enough to bring it down? They're finely balanced things

[glitchc]

Already tested. Success rate is too low. A great deal of aenergy gets wasted.

Remember, this is about asymmetric warfare. If the number of rounds or amount of energy required costs more than the drone it shoots down, then it's not an effective deterrent. Militaries are looking for single-shot weapons to take down drones. Fire once and move on. It's the only way to deal with a swarm. Think about it for a bit and it will become very obvious.