[jandrewrogers]

Reflectivity of the target doesn’t matter. The specified power levels are high enough by design that a reflective surface will instantly be converted into plasma.

Even if you covered the target in dielectric mirrors specifically engineered for the wavelength of the laser, assuming such a thing was even feasible on a cost, weight, and functional basis for the target, you would have to keep them spotlessly clean in an operational military environment for them to be effective — an impossible task.

Hence why the military doesn’t concern itself with shiny targets. At the power levels they target, nothing real can be sufficiently shiny as a matter of practical physics.