Which is very cool, but still very experimental and appears to only block a single frequency range (not what OP was proposing). I've also yet to see any publish

Which is very cool, but still very experimental and appears to only block a single frequency range (not what OP was proposing). I've also yet to see any published specs at all for the stuff (i.e. what's the actual optical density at those wavelengths?), so I'm a little skeptical still.