High-Impedance Surfaces for Above-IC Integration of Cooled Bolometer Arrays at the 350-μm Wavelength

High-impedance surfaces (HIS) are investigated here for the above-IC integration of sub-millimeter-wave (350 µm here) detectors on CMOS electronics using standard thin film manufacturing processes and materials. We demonstrate theoretically and experimentally the efficient optical absorption of a resistive dipole array above an HIS at cryogenic temperature. More specifically, an absorption above 78% in linear polarization is obtained over a bandwidth of 100 µm around a center wavelength of 350 µm. These results confirm the promising performances of HIS structures in the perspective of future polarimetric bolometers in terms of absorption efficiency, bandwidth and cross-polarization discrimination.