Opaque pixel mask with a broadband absorbing metasurface: application to infrared detectors

We present an imager architecture comprising dark and active pixels allowing the simultaneous measurement of photonic and dark current, which is of particular interest for low-photon-flux astronomical applications. The principle of operation relies on both the total opacity of a thin metallic screen of sufficient area and the anti-reflective properties of well-designed resonant metal-dielectric gratings made on the same screen. The concept is exemplified in the context of cooled HgCdTe hybrid detectors, at short- and long-wave infrared ranges.