Spectral cross-talk in dual-band quantum well infrared detectors

We propose a general definition of the spectral cross-talk in dual-band infrared (IR) photodetectors, based on the common information carried by the spectral channels. This definition includes detector characteristics as well as scene characteristics and can be applied to any real configuration. We use it to evaluate narrowband and wideband quantum well infrared photodetector structures and set up their interest for dual-band imaging. The spectral cross-talk is negligible for interband IR $(3–5\mu \mathrm{m}∕8–12\mu \mathrm{m})$ applications and can be minimized for intraband IR $(8–12\mu \mathrm{m})$ applications by properly tailoring the responsivity peaks.