Indium Gallium Arsenide Focal Plane Array and Camera for Low-Light Level 1-2 Micron Imaging

We propose to develop and deliver a high-performance 1280x960 element camera for low-light imaging of 1-2 ¿m light. The night sky provides illumination from moonlight, starlight, and "night glow". In the absence of moon and starlight, the primary radiance is from night glow in the 1-2 ¿m band peaking at 1.6 ¿m. During this program, we will develop and deliver an InxGa1-xAs-based low-light level camera featuring a 1280x960 element InGaAs focal plane array (FPA) whose alloy composition provides optimum detectivity of 1-2 ¿m night glow and low-noise camera electronics. During Phase I, we will model the detectivity trade-off resulting from extending the wavelength band of the InGaAs beyond the lattice-matched 1.7 ¿m cutoff which will increase the night glow signal detected but will also increase the dark noise of the FPA. We will use the Sensors Unlimited/Rockwell International buffered gate modulated CMOS multiplexer readout to provide 128x128 FPAS from both lattice-matched and extended wavelength InxGa1-xAs. Low-noise support electronics will be developed to allow quantitative characterization of the FPAs. The Phase I deliverable will include test results from both 128x128 FPAS in the 1-2 ¿m band. In Phase II, we will design and build the 1280x960 multiplexer and InGaAs array, optimize the low-noise electronics and deliver the high-resolution camera. The primary benefit derived from this proposal will be the development of a camera capable of high resolution imaging under low-light level conditions, including the overcast night sky. Secondary benefits will include a wide range of short wave infrared applications such as industrial thermal imaging, imaging spectroscopy, and the sub-surface inspection of fine art.