Single-Photon Project Launched
MILAN, Aug. 2, 2010 — “MISPIA” (Microelectronic Single-Photon 3-D Imaging Arrays for low-light high-speed safety and security applications) is a new collaborative research project funded by the European Commission in its Seventh Framework Programme for research, technological development and demonstration activities (2007-2013). The program was launched in June under the coordination of the Polytechnic of Milan, Electronics and Information Department. According to the grant agreement (#257646) signed between the project coordinator and the European Community, the project will be funded for about €2.6 for performing activities for 36 months in the field of photonics.
Recently, more than 20 representatives of the MISPIA consortium met in Milan to start the project activities. They will have the occasion to present their expertise to the other members of the consortium, but also to discuss in-depth requirements, specifications and constrains of the devices to be developed within the MISPIA project.
Many social needs require the acquisition of images at low light levels (possibly with no artificial illumination), at video or even higher frame rates (possibly thousands of frames per second, fps), and with distance-resolution (possibly millimeter precision). Currently, the imager market offers a broad portfolio of either commercial- or scientific-grade cameras, ranging from consumer CMOS active pixel sensor (APS) cameras up to high-end CCD imagers. None of them simultaneously offer high speed and ultrahigh sensitivity: CCDs reach the single-photon level, but necessarily require cooling and long integration times (i.e., very low frame rates); APS imagers provide video rates but with relatively limited detection efficiency, thus requiring bright illumination scenes. The MISPIA concept is to provide simultaneously both high frame rates and single-photon sensitivity chips with monolithic integration of single-photon avalanche diode (SPAD) pixels and sophisticated in-pixel intelligence able to process at the pixel-level intensity-data and depth-ranging information, enabling 3-D mapping of rapidly changing scenes in light-starved environments.
MISPIA proposes to exploit both standard CMOS technology, for cost-effective 2-D imaging and 3-D ranging cameras, and highly innovative beyond the state-of-the-art SOI/CMOS processing, for advanced imager performance.
MISPIA’s idea is to develop advanced microelectronic SPAD array chips able not only to count single photons, but also to accurately tag them with their arrival time (“single photon timing”) and so provide a full image (“single-photon imaging”) of the object under investigation. Therefore, MISPIA aims to conceive, develop and fabricate photonic and microelectronic technologies for cost-effective manufacturing of very fast, highly sensitive 2-D and 3-D SPAD cameras running at higher speed than standard video rate.
The MISPIA consortium consists of seven partners, who are among the leading European research groups in their fields:
• Politecnico di Milano, Italy (SPAD arrays and single-photon instrumentation)
• Fraunhofer-Gesellschaft zur Foerderung der Angewandten Forschung E.V., Germany (CMOS sensor fabrication and advanced SOI processes)
• Heriott-Watt University, UK (design and fabrication of microlens arrays)
• Micro Photon Devices s.r.l., Italy (development of time-correlated single-photon counting detection modules and cameras)
• Centro Ricerche Fiat scpa, Italy (safety applications in automotive field)
• EMZA Visual Sense Ltd., Israel (security surveillance monitoring)
• CF Consulting srl, Italy (management and dissemination of European projects)
The MISPIA Project will have major impacts on technological fields, application environments and end-user needs, because MISPIA technology for SPAD arrays, 2-D imaging and 3-D ranging chips will define a new paradigm in the fields of silicon photonics and microelectronics integration and of advanced ultrasensitive time-resolved and spectrally-resolved imaging. Not only safety and security scenarios will benefit by MISPIA cameras, but also completely different fields. The European Union will become more and more competitive against US, Japan and Canada, and will acquire a renowned leadership in conceiving, manufacturing and deploying ultrahigh sensitivity and fast camera sensor chips and systems.
Novel photonics components will push towards further chances to achieve MISPIA foreseen impacts. Growing progress in laser and LED sources, with higher efficiency and different wavelengths, can improve the 3-D scene illuminator (hence signal quality and signal-to-noise ratio), the multispectral ranging approach (e.g., to near-ultraviolet), and the overall 3-D system compactness. Also, progress in CMOS technologies, crystallographic quality, and manufacturing yield will render the SPAD chips even more appealing, due to performance improvements (e.g., lower dark-counting rate and afterpulsing, higher uniformity, etc.), and cost reduction.
Innovative scientific research and growing studies on single-photon detectors and time-resolved techniques can raise interest for further developments of smart-pixels and arrays within the MISPIA project. Finally, the microelectronic scalability of the proposed MISPIA CMOS SPAD imagers will positively impact on further advancement on SPAD array density (toward megapixels), in-pixel smartness (more complex in-pixel and on-chip processing), and overall imager compactness.
For more information, visit: www.polimi.it
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