Either IBM has cracked optically transparent coatings that cycle from 300 to 1K repeatedly and acrylic that has a metal's thermal conductivity, or it's a sham.
Oh hush, you're not going to nerd snipe me into doing the thermal flux calculations today.
Optical photons don't carry an impossible amount of energy: I've seen liquid helium through a small coated window. The window was there for ion beam purposes, not "entertaining the grad student", and it was a big element in the heat budget!
Really hard to tell which it could be.