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Proceedings Paper

Leonardo (formerly Selex ES) infrared sensors for astronomy: present and future
Author(s): Ian Baker; Chris Maxey; Les Hipwood; Keith Barnes
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Paper Abstract

Many branches of science require infrared detectors sensitive to individual photons. Applications range from low background astronomy to high speed imaging. Leonardo in Southampton, UK, has been developing HgCdTe avalanche photodiode (APD) sensors for astronomy in collaboration with European Southern Observatory (ESO) since 2008 and more recently the University of Hawaii. The devices utilise Metal Organic Vapour Phase Epitaxy, MOVPE, grown on low-cost GaAs substrates and in combination with a mesa device structure achieve very low dark current and near-ideal MTF. MOVPE provides the ability to grow complex HgCdTe heterostructures and these have proved crucial to suppress breakdown currents and allow high avalanche gain in low background situations. A custom device called Saphira (320x256/24μm) has been developed for wavefront sensors, interferometry and transient event imaging. This device has achieved read noise as low as 0.26 electrons rms and single photon imaging with avalanche gain up to x450. It is used in the ESO Gravity program for adaptive optics and fringe tracking and has been successfully trialled on the 3m NASA IRTF, 8.2m Subaru and 60 inch Mt Palomar for lucky imaging and wavefront sensing. In future the technology offers much shorter observation times for read-noise limited instruments, particularly spectroscopy. The paper will describe the MOVPE APD technology and current performance status.

Paper Details

Date Published: 29 July 2016
PDF: 8 pages
Proc. SPIE 9915, High Energy, Optical, and Infrared Detectors for Astronomy VII, 991505 (29 July 2016); doi: 10.1117/12.2231079
Show Author Affiliations
Ian Baker, SELEX ES Infrared Ltd. (United Kingdom)
Chris Maxey, SELEX ES Infrared Ltd. (United Kingdom)
Les Hipwood, SELEX ES Infrared Ltd. (United Kingdom)
Keith Barnes, SELEX ES Infrared Ltd. (United Kingdom)

Published in SPIE Proceedings Vol. 9915:
High Energy, Optical, and Infrared Detectors for Astronomy VII
Andrew D. Holland; James Beletic, Editor(s)

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