Experimental verification of backward wave propagation at photonic crystal surfaces

Backward wave propagation is the true manifestation of left-handed electromagnetism and not negative refraction which occurs also at the interface of right-handed systems. Here we experimentally demonstrate in a direct fashion the backward wave propagation phenomenon, which takes place at the surface of a properly designed photonic crystal. Our microwave experiment could open other venues for the verification of left-handed behavior in optical metamaterials. (C) 2007 American Institute of Physics.