Over the years there has been considerable investments in dualband infrared focal plane array (FPA) technology. Both quantum well photodetector and HgCdTe photovoltaic approaches have now achieved dualband-imaging capability. The fruits of these investments are being realized with FPAs that approach levels of performance and maturity sufficiently high to meet end-user needs. Dualband FPAs were developed primarily in support of conceptual surveillance, acquisition and tracking scenarios for a variety of target types. These dualband FPAs may be considered the functional equivalent of dual-channel imagers comprising a dichroic beamsplitter and two distinct FPAs. The volume and cooling requirements of the dual-channel imagers are appreciable relative to the single, dualband FPA. Novel spectral imaging concepts are also enabled with the current dual band, and future multi-waveband, FPA technologies.
Paul D. LeVan, Paul D. LeVan,
"Perspectives on dualband infrared focal plane array efforts", Proc. SPIE 5563, Infrared Systems and Photoelectronic Technology, (21 October 2004); doi: 10.1117/12.565674; https://doi.org/10.1117/12.565674