Reposting what I posted as AC up above on accident: Just to clarify: the demonstrated lens operates at 1.55 micron (near-IR). The same phase-control concept has already been demonstrated in the mid-IR by the same authors, in the terahertz (THz) by some other authors. The approach is trivially generalizable to any longer wavelength (shorter frequency) which means millimeter wave, radio waves, etc, though it is unclear if it is very useful in the radio frequency region compared to conventional receiving/transmitting phased arrays.

Hey guys, I'm one of the co-authors of that Nature Materials paper. Please let me know if you have any technical questions about the work. I'm not an expert on terahertz semiconductor lasers or their applications (I was really only involved in the surface patterning of the facet with the spoof plasmonic structures), but I'll do my best to answer any questions you might have.

I'd recommend Melanie Mitchell's "An Introduction to Genetic Algorithms".