I wonder what the countermeasures to these will be. To construct your drones and missiles out of highly reflective mirrors?
For lightweight applications like drones I would hazard a guess that specifically engineered aerogels would do well.
My Children of a Dead Earth favorite is a thin layer of something reflective for short-burst thermal reflection, under that something that can take high temperatures like carbon-carbon for sustained lasers, and then a big slab of aerogel to keep that heat off of the more delicate bits.