Metallic photonic band gap (MPBG) filter structures operating at far infrared wavelengths have been designed, fabricated, and characterized. The MPBGs are multilayer metallic meshes imbedded in a flexible polyimide dielectric. Depending on the periodic pattern of the metal grids, the filters have either simple high-pass or more complex transmission characteristics. The critical frequencies of the filters depend on the spatial periodicity of the metal grids and the interlayer separation. Optical transmission measurements on a high-pass structure show cutoff frequency of 3 THz and attenuation of more than 35 dB in the cutoff region, in good agreement with predicted results. Band-reject filters show similarly good attenuation and large fractional bandwidths. The filters maintain their optical characteristics after repeated bending, demonstrating mechanical robustness of the MPBG structure.

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Polymer electrolyte films based on poly(ethylene oxide) doped with salt sodium nitrate and ionic liquid (IL; 1-ethyl 3-methylimidazolium thiocyanate) have been prepared and characterized by differential scanning calorimetry (DSC) and impedance spectroscopy. The relative percentage of crystallinity of polymer electrolytes has been calculated by using DSC thermograms and electrical properties by using impedance spectroscopy. The incorporation of IL in polymer matrix increases the conductivity of polymer electrolyte. The maximum value of ionic conductivity of polymer electrolyte is found to be 1.93 × 10−4 S m−1 with 9 wt% IL.