[nradov]

Reflectivity doesn't matter in practice. No finish is sufficiently reflective and so the first part of the laser pulse burns it off and then the rest of the pulse gets through.

An ablative heat shield can be more effective, although that adds weight and interferes with sensors. Spinning the target can also help a little by spreading the heat across a wider surface area.

[shpx]

What about shooting out a gas that’s dark in infrared between yourself and the laser?

[jandrewrogers]

Nope, same issue, it would absorb the energy and turn into a very low density plasma, blocking nothing. That is equivalent to very weak ablation shielding.

In fact, using a high-power laser to punch a hole in the atmosphere, essentially creating a functional vacuum by superheating the atmosphere in the beam path, is an old school engineering trick for exotic systems. Though in those cases, they tune the laser so that it gets absorbed by the atmosphere (similar to the gas you are suggesting). The use case is roughly analogous to employing supercavitation on torpedos.

[ianai]

Where can I read up more on such applications?