I'd like to see tha patent filing for that: as far as I understand the relevant physics, the smaller the aperture the greater the diffraction. So the gains available are very limited.

Not really. It seems that by "drilling" a specific pattern of holes into some optical materials weird effects can be created. This is how a negative index of refraction can be obtained. I think it is therefore quite likely that they are actually using diffraction to their advantage.

I am not an expert and I hope someone with specific knowledge of photonics and photonic crystals would comment.