On 9/22/15, Juan <juan.g71 at gmail.com> wrote: > ... > Isn't it possible to focus any sort(frequency) of EM wave, at > least in theory? in theory, with "metamaterials", yes. in practice this is akin to the perfect invisibility cloak problem, full of devilish details... a full spectrum Superlens for any EM freq would be quite handy indeed :) best regards,