In one embodiment, a multiband infrared (IR) detector array includes a metallic surface having a plurality of periodic resonant structures configured to resonantly transmit electromagnetic energy in distinct frequency bands. A plurality of pixels on the array each include at least first and second resonant structures corresponding to first and second wavelengths. For each pixel, the first and second resonant structures have an associated detector and are arranged such that essentially all of the electromagnetic energy at the first wavelength passes through the first resonant structure onto the first detector, and essentially all of the electromagnetic energy at the second wavelength passes through the second resonant structure onto the second detector. In one embodiment, the resonant structures are apertures or slots, and the IR detectors may be mercad telluride configured to absorb radiation in the 8-12 μm band. Detection of more than two wavelengths may be achieved by proper scaling. A method of forming an IR detector array is also disclosed.