A HEL focuses optical power on one point and heats or burns the target: drones, missiles, optics and sensors. Its strengths are speed-of-light effect, pinpoint precision, a low cost per shot and a deep magazine. But the limitations are substantial:
- Line of sight required: a laser does not bend over the horizon (Radar) and does not go through mountains or buildings.
- Dwell time: the target has to be "held" for several seconds to deliver enough energy — difficult against fast, manoeuvring targets.
- Atmosphere: absorption and scattering weaken the beam, and thermal blooming (the beam heats the air and defocuses) comes into play. Rain, fog and dust make this worse — compare the atmospheric windows for IR (Infrared).
Which systems are in service or in development at the end of 2026, and what their first use has taught, is covered in From trial to service: the status at the end of 2026.