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Proceedings Paper

Photon counting imaging: the DigitalAPD
Author(s): Stephen Bellis; Reuben Wilcock; Carl Jackson
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Paper Abstract

Geiger Mode avalanche photodiodes offer single photon detection, however, conventional biasing and processing circuitry make arrays impractical to implement. A novel photon counting concept is proposed which greatly simplifies the circuitry required for each device, giving the potential for large, single photon sensitive, imaging arrays. This is known as the DigitalAPD. The DigitalAPD treats each device as a capacitor. During a write, the capacitor is periodically charged to photon counting mode and then left open circuit. The arrival of photons causes the charge to be lost and this is later detected during a read phase. Arrays of these devices have been successfully fabricated and a read out architecture, employing well known memory addressing and scanning techniques to achieve fast frame rates with a minimum of circuitry, has been developed. A discrete prototype has been built to demonstrate the DigitalAPD with a 4x4 array. Line rates of up to 5MHz have been observed using discrete electronics. The frame burst can be transferred to a computer where the arrival of single photons at any of the 16 locations can be examined, frame by frame. The DigitalAPD concept is highly scalable and is soon to be extended to a fully integrated implementation for use with larger 32x32 and 100x100 APD arrays.

Paper Details

Date Published: 6 February 2006
PDF: 10 pages
Proc. SPIE 6068, Sensors, Cameras, and Systems for Scientific/Industrial Applications VII, 60680D (6 February 2006); doi: 10.1117/12.642755
Show Author Affiliations
Stephen Bellis, SensL Technologies Ltd. (Ireland)
Reuben Wilcock, SensL Technologies Ltd. (Ireland)
Carl Jackson, SensL Technologies Ltd. (Ireland)

Published in SPIE Proceedings Vol. 6068:
Sensors, Cameras, and Systems for Scientific/Industrial Applications VII
Morley M. Blouke, Editor(s)

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