Experimental demonstration of one-way slow wave in waveguide involving gyromagnetic photonic crystals

We experimentally demonstrate that electromagnetic waves in the waveguide comprising gyromagnetic photonic crystals (GMPCs) and a metal cladding are robust one-way slow waves in the frequency range of the chiral edge states of GMPC. Measured with phase shift technique in microwave regime, the group velocity of the wave could be one order of magnitude smaller than the speed of light with group index up to 15.6. The one-way wave with much slower group velocity is shown by retailoring the waveguide further. This waveguide provides a potential way to realize robust slow-light transmission lines in electromagnetic or optical systems. (C) 2013 AIP Publishing LLC.