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A novel bandwidth-tunable notch filter is proposed based on the guided-mode resonance effect. The notch is created due to the superposition spectra response of two guided-mode resonant filters. The compact, bandwidth tuning capability is realized by taking advantage the effect of spectra-to-polarization sensitivity in one-dimensional classical guided-mode resonance filter, and using a liquid crystal polarization rotator for precise and simple polarization control. The operation principle and the design of the device are presented, and we demonstrate it experimentally. The central wavelength is fixed at 766.4 nm with a relatively symmetric profile. The full width at half maximum bandwidth could be tuned from 8.6 nm to 18.2 nm by controlling the applied voltage in electrically-driving polarization rotator.

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We report a large-area broadband optical absorber consisting of Ag/SiO stacked plasmonic layers fabricated on a self-assembly polystyrene sphere monolayer using the glancing angle deposition. Such an absorber can absorb more than 90% of light in the spectral range of 350 - 850 nm when the polystyrene spheres have a diameter of 750 nm. The broadband absorption is due to the overlap of localized plasmonic resonance wavelengths resulting from different patchy sizes and shapes of Ag coating on polystyrene spheres. Such a simple, flexible and large-area absorber has potential applications in light cloaking and energy conversion.

A compact, tunable guided-mode resonant (GMR) filter whose spectral reflectance wavelength varies as a function of the spatial position on the device is experimentally demonstrated. The filter incorporates a wedge-shaped waveguide layer that is fabricated using masked ion beam etching (MIBE) technology. A ceramic plate mask consisting of an isosceles triangular window is placed between the ion source and the sample to achieve different etching times at difference locations on the film. The increment in the magnitude of the film thickness is approximately 50 nm over a length of 33 mm, which results in a primary reflectance peak whose spectral location spans the range of 684.2-725.3 nm. The device is designed using the rigorous coupled-wave analysis (RCWA) method, and the proposed device is directed toward the practical application of GMR tunable filters.