Uncooled Terahertz real-time imaging sensors developed at LETI:
present status and perspectives
F. Simoens
, Jérôme Meilhan
, Jonathan Oden
, Laurent Dussopt
, Jean-Alain Nicolas
, Nicolas
, Gilles Sicard
, Alexandre Siligaris
, Bruno Hiberty
CEA-Leti, Minatec Campus, Université Grenoble Alpes, 17, Rue des Martyrs, 38054 Grenoble,
i2S, F33600 Pessac, France.
The commercial spread of terahertz (THz) cameras has to fulfil simultaneously the
criteria of high sensitivity and low cost and SWAP (size, weight and power). Monolithic siliconbased 2D sensors integrated in uncooled THz real-time cameras are good candidates to meet these
requirements. Over the past decade, LETI has been studying and developing such arrays with two
complimentary technological approaches, i.e. antenna-coupled silicon bolometers and CMOS
Field Effect Transistors (FET), both being compatible to standard silicon microelectronics
LETI has built upon its know-how in thermal infrared bolometer sensors a proprietary
architecture for THz sensing. High technological maturity has been achieved as illustrated by the
demonstration of fast scanning of large field of view and the recent birth of a commercial camera
in collaboration with the French SME I2S.
Two FET-based approaches are developed at LETI: direct detection and heterodyne
detection. The former technic has reached the most advanced demonstration with 31x31 arrays
and real-time 2D imaging, while the latter has been demonstrated with single-point heterodyne
detector and raster scanning and showed very promising sensitivity.
The authors describe the present status of these developments and perspectives of
performance evolutions are discussed.
Fig.1. Three technologies of uncooled Terahertz real-time imaging sensors developed at LETI
[1] Simoens F., Meilhan J., “Terahertz real-time imaging uncooled array based on antenna- and cavitycoupled bolometers,” Philosophical Transactions of the Royal Society of London A: Mathematical,
Physical and Engineering Sciences 372(2012), 20130111 (2014).
[2] A. Boukhayma, J-P. Rostaing, A. Mollard, F. Guellec, M. Benetti, G. Ducournau, J-F. Lampin, A.
Dupret, C. Enz, M. Tchagaspanian, J-A. Nicolas, “A 533pW NEP 31×31 pixel THz image sensor based
on in-pixel demodulation,” IEEE European Solid State Circuits Conference (ESSCIRC), 303-306 (2014)
[3] A. Siligaris, Y. Andee, E. Mercier, J. Moron Guerra, J.-F. Lampin, G. Ducournau, Y.
Quere, “A 278 GHz heterodyne receiver with on-chip antenna for THz imaging in 65 nm CMOS process,”
IEEE European Solid State Circuits Conference (ESSCIRC), 307-310 (2015).

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