Anti-drone lasers and microwave
Directed-energy systems defeat drones with a laser beam or a microwave pulse. Both are real and both are military. The interesting difference between them is single target versus many.
Key facts
- Directed energy covers two distinct approaches. A high-energy laser burns a single aircraft at a point on its structure. A high-power microwave pulse disrupts the electronics of everything within a cone.
- A laser engages one target at a time and needs to hold the beam on a moving aircraft long enough to cause damage, which makes tracking precision the limiting factor rather than power.
- High-power microwave is the answer to a swarm, because it affects a volume rather than a point, and it is correspondingly indiscriminate about other electronics in that volume.
- Both are mitigation, restricted in the United States to authorised federal agencies and certified state, local, tribal and territorial law enforcement and correctional agencies.
- Laser performance degrades in fog, rain, dust and atmospheric turbulence, so a system demonstrated in clear desert conditions is not describing a coastal or northern winter.
- Deployment at present is essentially military, so these systems are generally unavailable for a commercial site to specify, budget for or operate.
Two technologies under one heading
Directed energy sounds like one thing. It is two, and they solve opposite problems.
A high-energy laser puts a concentrated beam on a single point of a single aircraft and holds it there until something structural fails. It is precise, and its difficulty is tracking: keeping a beam on a specific part of a small, moving, possibly manoeuvring object at distance, for long enough.
High-power microwave emits a pulse that disrupts electronics across a cone. It does not need to aim at a point, so it can affect several aircraft at once. The same property makes it indiscriminate about other electronic equipment within that volume, which limits where it can be used.
Why they exist
The argument for directed energy is economic, and it is the same argument as for interceptors, taken further.
An interceptor still costs something per engagement. A laser’s marginal cost per shot is electricity. Against a threat arriving continuously and in volume, that difference decides whether a defence can be sustained at all.
This is a national-scale argument. It matters enormously to a military planner and hardly at all to a facility manager whose problem is a drone appearing over the site every few weeks.
What limits them
Lasers are weather-dependent in a way that marketing rarely emphasises. Fog, rain, dust and atmospheric turbulence all scatter and absorb the beam, so range and time-to-effect degrade with conditions. A figure obtained in clear desert air describes clear desert air.
There is also an eye-safety hazard zone around any high-energy laser, which is a significant siting constraint at any location where people are present.
High-power microwave carries its own version of the same problem: the cone that disrupts the drone’s electronics does not distinguish between the drone’s electronics and anyone else’s.
Where this leaves a civilian buyer
Nowhere, for now, and it is better to say so plainly than to leave it implied.
Directed energy is restricted as mitigation, and it is deployed by militaries and federal agencies rather than sold to venues and industrial sites. It appears in this field’s coverage far out of proportion to its availability, because it is visually striking and strategically significant.
For an organisation trying to decide what to actually do, it is not on the list. Detection is.
FAQ
▸Could a data centre or stadium buy a laser system?
No, on two counts. Directed energy is mitigation and the authority does not extend to private operators, and deployment in practice is military and government rather than commercial. A proposal offering one to a civilian site is describing something that is not available to it.
▸What is the real difference between laser and microwave?
How many targets. A laser is precise and engages one aircraft at a time, so it suits a single intruder and struggles against several. High-power microwave affects everything electronic within a cone, which is the answer to a swarm and the reason it cannot be used casually near anything else with electronics in it.
▸Is a laser silent and invisible in use?
The beam itself is generally invisible, though the effect is obvious. The target heats, may burn and comes down. There is also an eye-safety hazard zone around the system, which is a substantial siting constraint wherever people are present.
▸Why is directed energy discussed so much if almost nobody can use it?
Because it addresses the cost problem that dominates military thinking, where the magazine is effectively electricity rather than interceptors. That argument is genuinely important at national scale and close to irrelevant for a civilian site facing occasional intrusion, which is the gap between the coverage and the buying decision.