Hybrid dual-color MWIR detector for airborne missile warning systems

Dual-color imaging in the Mid-Wave Infrared (MWIR) is required in some airborne Missile Warning Systems (MWS) due to its ability to reduce the number of false alarms in this application by comparing the signal in the two spectral bands. Furthermore, such systems demand high frame rate, spatial resolution, and spectral resolution, while at the same time call for simultaneous collection and readout of the two color images. Monolithic dual-color Focal Plane Arrays (FPAs) lack at least some of these requirements. In this work we introduce a new hybrid dual-color detector based on two 480×384/20μm digital InSb FPAs, assembled in a single Dewar, where the high degree of spatial registration between the two color channels enables a solution that achieves the above requirements. Each FPA has its own cold shield and spectral filter, and the signal is snapshot integrated and read out in parallel to obtain complete dual-color simultaneity. The sensor imaging optics is integrated inside the Dewar for both channels in order to reduce the overall system size and weight, and improve its performance at the extreme environmental conditions imposed by this application. In this case the hybrid dual-color Integrated Dewar-Cooler Assembly (IDCA) is designed for a very wide field of view (>100°), suited for the specific airborne Missile Warning System (MWS). We present the independent electro-optical results of both the red and the blue channels, together with the measured negligible spectral cross-talk and high spatial registration between them.