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Proceedings Paper

Linear-mode avalanche photodiode arrays in HgCdTe at Leonardo, UK: the current status
Author(s): Ian Baker; Chris Maxey; Les Hipwood; Vincent Isgar; Harald Weller; Mark Herrington; Keith Barnes
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Paper Abstract

Linear-mode avalanche photodiode arrays, LmAPDs, based on bandgap engineered HgCdTe, grown by Metal Organic Vapour Phase Epitaxy, MOVPE, can produce virtually noise-free infrared sensors. These are required for applications in big science, security and biochemistry. A custom device called SAPHIRA (320x256/24μm) has been designed specifically for LmAPDs. SAPHIRA has been deployed as a wavefront sensor for adaptive optic systems in nine major telescopes and notably five devices control the four 8.2 metre telescopes of the VLT interferometer. These demanding applications have driven frames rates up to 200 kframes/s and avalanche gains to x600 achieving read noise as low as 0.26 e- rms and enabling single photon counting. The detector is baselined for time-domain astronomy vital for exoplanet spectroscopy and understanding the physics of active stellar objects. The three 30 metre class telescopes currently under construction and the three candidate space telescopes, HabEx, Luvoir and EZE will depend on noise-free infrared detectors at very low dark current. Work at the University of Hawaii and European Southern Observatory has demonstrated dark currents in the 4-10 electrons/hour range and with avalanche gain offers the prospect of higher science return from these instruments. A 1kx1k/15μm 3-side buttable array is currently in development to service extreme low background applications especially spectroscopy. A 512x512/24μm SAPHIRA array with 64 parallel video outputs is in development for pyramid wavefront sensing on the European Extremely Large telescope, ELT, mirror co-phasing and rapid time-domain astronomy.

Paper Details

Date Published: 13 May 2019
PDF: 10 pages
Proc. SPIE 10980, Image Sensing Technologies: Materials, Devices, Systems, and Applications VI, 109800K (13 May 2019); doi: 10.1117/12.2519830
Show Author Affiliations
Ian Baker, Leonardo MW Ltd. (United Kingdom)
Chris Maxey, Leonardo MW Ltd. (United Kingdom)
Les Hipwood, Leonardo MW Ltd. (United Kingdom)
Vincent Isgar, Leonardo MW Ltd. (United Kingdom)
Harald Weller, Leonardo MW Ltd. (United Kingdom)
Mark Herrington, Leonardo MW Ltd. (United Kingdom)
Keith Barnes, Leonardo MW Ltd. (United Kingdom)

Published in SPIE Proceedings Vol. 10980:
Image Sensing Technologies: Materials, Devices, Systems, and Applications VI
Nibir K. Dhar; Achyut K. Dutta; Sachidananda R. Babu, Editor(s)

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