DARPA's advanced imaging systems to extend field of view

WASHINGTON. The Defense Advanced Research Projects Agency (DARPA) has developed the Focal arrays for Curved Infrared Imagers (FOCII) program to expand upon the current commercial trend for visible sensor arrays by extending the capability to both large and medium format midwave (MWIR) and/or longwave (LWIR) infrared detectors.

Graphic courtesy of the Defense Advanced Research Projects Agency.

The program seeks to develop and demonstrate technologies for curving existing state-of-the-art large format, high performance infrared (IR) focal plane arrays (FPA) to a small radius of curvature (ROC) to maximize performance, as well as curve smaller format FPAs to an extreme ROC to enable the smallest form factors possible while maintaining exquisite performance. FOCII will address this challenge through two approaches to fabricating a curved FPA.

The first involves curving existing FPAs, while keeping the underlying design intact. The focus of the research will be on achieving significant performance improvements over existing, flat FPAs, with a target radius of curvature of 70mm.  The second approach will focus on achieving an extreme ROC of 12.5 mm to enable a transformative reduction in the size and weight compared to current imagers.

The fundamental challenge that both approaches will face will be to mitigate the mechanical strain created by curving the FPGA, particularly in silicon, which is very brittle.