Observation of genuine wave vector (k or β) gap in a dynamic transmission line and temporal photonic crystals

By definition, a temporal photonic crystal (TPC) has a permittivity epsilon(t) that varies periodically with time. We prove that, in the long wavelength limit, a TPC is accurately mimicked by a dynamic transmission line (DTL) having a capacitance (inductance) per unit length equal to epsilon(t) (mu). Employing a DTL in the microwave region, we measured the photonic band structure, which results to display a genuine wave vector (k or beta) gap, in very good agreement with our theoretical model and the equivalent TPC. (C) 2015 AIP Publishing LLC.