The development of, and applications for, extended response (0.7 to 1.7μm) InGaAs focal plane arrays

Historically, the natural structure of Indium Gallium Arsenide backside illuminated FPAs has allowed them to detect light with wavelengths between 0.9 and 1.7 μm. However, new wafer growth and processing methods have allowed extended response InGaAs imagers to be used in high sensitivity cameras to detect light down to 0.7 μm. These extended response imagers hold many advantages over standard cut-on InGaAs. One of these advantages is being able to detect beacons, lasers, and illuminators in the 800-900 nm range, light sources that have historically only been detectable with I2CCD cameras or night vision tubes, while simultaneously being able to detect the longer wavelength convert illuminators and lasers. Another advantage is capturing any additional available photons with wavelengths between 0.7 μm and 0.9 μm. This improves overall imaging capability in most low light level situations. This paper will address the methods used to achieve stable, high sensitivity extended response imagers, as well expand on the applications of this breakthrough.