“When you take a laser outdoors, the atmosphere becomes part of the system”

Prof. Eichhorn, high-energy lasers have suddenly become central to defense technology debates. Why now?

Marc Eichhorn: Two trends are converging: major progress in fiber lasers and beam combining, and a rapidly changing conflict landscape with growing use of unmanned aerial vehicles. This makes directed energy attractive because it enables highly precise engagement at the speed of light while drawing only electrical power—an almost unlimited “magazine”—at a very low cost per shot. This is exactly the profile needed for accurate, repeatable counter-UAS measures.

Many people assume it’s mainly about achieving “more kilowatts.” Is that true?

High output power matters, but operational capability is defined by predictable irradiance on target. In practice, this means holding a small spot on a fast, dynamic object long enough to create an effect. That requires an end-to-end system view: sensors, optics, control loops and real-time algorithms—plus the mitigation of atmospheric effects such as turbulence, absorption, thermal blooming and platform jitter. The laser is only one element in a tightly coupled chain.

Which core building blocks are you working on along this chain?

We cover the full span: scaling and characterizing laser sources, including beam combining; precise multi stage tracking concepts and sensors; and the simulation and modeling of atmospheric propagation so that performance can be predicted rather than guessed. In parallel, we investigate laser–matter interaction and laser safety, because field use demands both effectiveness and controlled risk.

How do you bridge the gap between models, lab setups and reality?

Validation is key. That’s why we are setting up HELIKS, a flexible, container based mobile high energy laser investigation system. Its modular architecture enables experiments even where infrastructure is limited and supports high power beams via coherent coupling, allowing realistic measurements of safety, atmospheric propagation, laser–matter interaction and overall system performance. These data feed directly back into our full system simulations.

How do you make the leap from demo to dependable capability?

High-energy lasers are not a single breakthrough component but a system of systems. Laser source, beam control, tracking, atmosphere and safety all interact. Dependable capability comes from investing in the less visible parts − robust tracking, propagation understanding and field experimentation − that turn impressive demos into predictable performance.

Marc Eichhorn is head of institute of Fraunhofer IOSB and division manager Defense.