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Proceedings Paper

Theoretical analysis and comparison of SWIR active imaging detectors
Author(s): Stéphane Demiguel
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Paper Abstract

This paper is a theoretical analysis and a comparison of imaging sensor technologies compatible with active imaging applications that operate in the SWIR band. Two types of sensors are commonly used: detectors with gain induced by internal photoelectron multiplication process (HgCdTe APD FPA and InGaAs/InP TE EBCMOS) and detectors without internal gain (InGaAs FPA). Active imaging requires a sensitive high-speed sensor able to detect a short, weak pulse backscattered from a target. The goal is to reach a sensitivity defined by a NEPh of 10 photons rms, and a SNR of 5-10 for an input signal of 100-200 photons/pulse/pixel. We demonstrate that the HgCdTe APD FPA detector with gain is intrinsically the best technology to fulfill the aforementioned requirements. In comparison, the InGaAs/InP TE EBCMOS also works well but suffers from limited quantum efficiency, less than 30% at the most. The main advantage of detectors with internal gain is their potential to amplify the laser signal above the readout noise level, under the condition that the excess noise factor induced by the multiplication process remains close to 1. The InGaAs FPA detector without gain is lower cost, however it exhibits a NEPh of around one order of magnitude higher and a SNR 3 to 6 times lower. At a system level, a more powerful laser will compensate for this difference but will also increase the cost. In conclusion to the tradeoff regarding performance versus cost, each specific system need should determine the best matched technology.

Paper Details

Date Published: 7 May 2009
PDF: 10 pages
Proc. SPIE 7298, Infrared Technology and Applications XXXV, 729836 (7 May 2009); doi: 10.1117/12.817926
Show Author Affiliations
Stéphane Demiguel, SAGEM, SAFRAN group (France)


Published in SPIE Proceedings Vol. 7298:
Infrared Technology and Applications XXXV
Bjørn F. Andresen; Gabor F. Fulop; Paul R. Norton, Editor(s)

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