An optical detector pixel element. The novel pixel element includes a metallic substrate having a plurality of resonant apertures, each aperture adapted to resonantly transmit electromagnetic energy in a distinct frequency band, and a plurality of detectors adapted to detect the energy transmitted by the apertures. Each aperture is adapted to collect energy incident on an area larger than the aperture and focus the energy into a smaller, localized region in which one or more of the detectors is placed. The plural apertures are positioned such that they collect energy incident on a substantially common area, but are of different sizes such that they are resonant to different frequencies. Energy in different frequency bands are therefore funneled through different apertures. In an illustrative embodiment, several identical pixel elements are joined together to form an array.