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Proceedings Paper

Gated IR imaging with 128 × 128 HgCdTe electron avalanche photodiode FPA
Author(s): Jeff Beck; Milton Woodall; Richard Scritchfield; Martha Ohlson; Lewis Wood; Pradip Mitra; Jim Robinson
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Paper Abstract

The next generation of IR sensor systems will include active imaging capabilities. One example of such a system is a gated-active/passive system. The gated-active/passive system promises long-range target detection and identification. A detector that is capable of both active and passive modes of operation opens up the possibility of a self-aligned system that uses a single focal plane. The detector would need to be sensitive in the 3-5 μm band for passive mode operation. In the active mode, the detector would need to be sensitive in eye-safe range, e.g. 1.55 μm, and have internal gain to achieve the required system sensitivity. The MWIR HgCdTe electron injection avalanche photodiode (e-APD) not only provides state-of-the-art 3-5 μm spectral sensitivity, but also high avalanche photodiode gain without minimal excess noise. Gains of greater than 1000 have been measured in MWIR e-APDs with a gain independent excess noise factor of 1.3. This paper reports the application of the mid-wave HgCdTe e-APD for near-IR gated-active/passive imaging. Specifically a 128x128 FPA composed of 40 μm pitch, 4.2 μm to 5 μm cutoff, APD detectors with a custom readout integrated circuit was designed, fabricated, and tested. Median gains as high as 946 at 11 V bias with noise equivalent inputs as low as 0.4 photon were measured at 80 K. A gated imaging demonstration system was designed and built using commercially available parts. High resolution gated imagery out to 9 km was obtained with this system that demonstrated predicted MTF, precision gating, and sub 10 photon sensitivity.

Paper Details

Date Published: 14 May 2007
PDF: 18 pages
Proc. SPIE 6542, Infrared Technology and Applications XXXIII, 654217 (14 May 2007); doi: 10.1117/12.719358
Show Author Affiliations
Jeff Beck, DRS Sensors and Targeting Systems, Inc. (United States)
Milton Woodall, DRS Sensors and Targeting Systems, Inc. (United States)
Richard Scritchfield, DRS Sensors and Targeting Systems, Inc. (United States)
Martha Ohlson, DRS Sensors and Targeting Systems, Inc. (United States)
Lewis Wood, DRS Sensors and Targeting Systems, Inc. (United States)
Pradip Mitra, DRS Sensors and Targeting Systems, Inc. (United States)
Jim Robinson, DRS Sensors and Targeting Systems, Inc. (United States)


Published in SPIE Proceedings Vol. 6542:
Infrared Technology and Applications XXXIII
Bjørn F. Andresen; Gabor F. Fulop; Paul R. Norton, Editor(s)

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