Polarization selective, graded-reflectivity resonance filter, using a space-varying guided-mode resonance structure.

We designed, fabricated, and tested, polarization selective, graded-reflectivity resonant filters; based on a radial-gradient spatially-distributed, guided-mode resonance device architecture. The demonstrated filters have polarized spectral-resonance responses, distributed across their aperture extent, in the range between 1535 nm and 1540 nm wavelengths. Spectral sensitivity was observed on device tests, for wavelength changes as low as 0.2 nm. Using multiple lithographic exposures and biasing exposure methods, the devices were engineered to have a sub-aperture region, with no hard boundaries or diffraction anomalies.