Wavelength selective filter based on polarization control in a photonic bandgap structure with a defect

We present a technique for achieving wavelength specific half-wave retardation upon reflection from an asymmetric one-dimensional photonic band-gap structure with a defect. The approach is based on a high finesse Gires-Tournois type interferometer and makes use of the large mode splitting of TE and TM defect modes that occurs in structures with a wide photonic band-gap. We use this structure to demonstrate a polarization-based selective tuneable filter with a narrow pass-band and wide rejection-band.