There's something non-intuitive (to me, anyway) in the Nimtz paper. In
addition to undersized waveguides, he states that waves can tunnel through
"periodic dielectric heterostructures". An illustration of this appears to
be nothing more than a series of alternating blocks of materials with
differing dielectric constants. This is the non-intuitive part. The
propagation velocity through either of them should be less than c, so how is
the total propagation velocity greater than c?
--"Withdraw in disgust is not the same thing as apathy." --R.E.M.