High phase retardation by waveguiding in slanted photonic nanostructures

We report a physical mechanism leading to high phase retardation in slanted photonic nanostructures. The phenomenon is based on the waveguiding of the transverse electric polarization component inside the slanted pillars, while the transverse magnetic component is not guided. Such a mechanism leads to very high phase retardation even with shallow structures that are suitable also for lithographical mass production. We present physical principle, numerical analysis of the phenomenon and designs for half-wave retarders. As an experimental result, a slanted grating producing 177 degrees retardation and 95.5% efficiency is presented.