Polarizing optical devices based on embedded one-dimensional subwavelength-structured photonic-crystal layers

Quarter-wave retarders (QWR) that employ total internal reflection (TIR) and interference of light in a transparent thin-film coating at the base of a prism are presented. Explicit equations that guide the optimal design are provided. The optimal refractive index and normalized thickness of QWR coatings on glass and ZnS prisms are determined as functions of the internal angle of incidence from 45° to 75°. An achromatic QWR that uses an Si3N4-coated N-BK10-Schott glass prism is also presented with retardance error of < 3° over the 400-600 nm wavelength range.;An iterative procedure for the design of a polarizing beam splitter (PBS) that uses a form-birefringent, subwavelength-structured, one-dimensional photonic-crystal layer (SWS 1-D PCL) embedded in a high-index cubical prism is presented. The PBS is based on index matching and total transmission for the p polarization and total internal reflection for the s polarization at the prism-PCL interface at a 45° angle of incidence. A high extinction ratio in reflection (>50 dB) over the 4-12 mum IR spectral range is achieved using a SWS 1-D PCL of ZnTe embedded in a ZnS cube within an external field of view (FOV) of +/-6.6° and in the presence of grating filling factor errors of up to +/-10%. Comparable results, but with a wider field of view, are also obtained with a Ge PCL embedded in a Si prism. A design for visible spectrum (553-713 nm) PBS SWS 1-D PCL of ZnTe embedded in a ZnS cube is also presented. The PBS shows a FOV of +/-7°.;A circular polarizing beam splitter (CPBS) with equal throughput for p and s polarization using SWS 1-D PCL embedded in a high-index cubical prism is introduced. A dual QWR in transmission and reflection with 50-50% CPBS is designed using the PCL. Such a PBS shows large deviation from the design point as a result of small changes in the design parameters; e.g. a change of ≈ 10% in the filling factor results in > 12° shift from the 90° phase shift between p and s polarizations, which limits the practical utility of the device.;Keywords. Beam Splitters, Form Birefringence, Gratings, Photonic Crystal, Polarization, Quarter-Wave Retarder.