Polarization-dependent reflective dispersion relations of photonic crystals for waveplate mirror construction

We have measured the polarization-dependent phase shift imparted to the radiation reflected by a two-dimensional photonic crystal within the band gap spectral region. We show that the relative phase between retroreflected basis polarizations can be large, reaching and exceeding a quarter of a wave in spectral regions of extremely high reflectivity for certain crystals. Using this property, we have directly experimentally demonstrated the operation of a reflective quarter-waveplate. All-dielectric, reflective waveplates could generate new applications involving polarization control