A 640 × 512 InGaAs camera for range-gated and staring applications

We report on a 640 x 512 pixel, 25 μm pitch, InGaAs focal plane array based camera with the ability to perform range-gated imaging, while also allowing integration times longer than 32 ms for imaging in a staring mode at video rates. The combination of gated and video imaging is achieved through a high bandwidth pixel with a capacitive transimpedance amplifier (CTIA) design. The CTIA pixel may be switched between two feedback capacitor sizes to allow two different sensitivities and capacities, depending on the illumination conditions. Anti-blooming is included in the pixel to prevent charge spreading from oversaturated pixels. All pixels are gated simultaneously for "snapshot" exposure. The all solid-state gated camera is very reliable, in addition to being small and lightweight. The low dark current and high bandwidth of the InGaAs photodetectors enables both high sensitivity imaging at long exposure times and high bandwidth at short exposure times. The spectral response of InGaAs extends from 0.9 μm to 1.7 μm, allowing the use of eye-safe commercially available pulsed lasers with 1.5 μm wavelength, several millijoule pulse energies, and nanosecond scale pulse durations.

[1]  Robert M. Brubaker,et al.  A 320x256 InGaAs camera for range gated and staring applications , 2005, SPIE Defense + Commercial Sensing.