Megapixel Image Sensor for Low Light

Sample photo taken with the one Megapixel Quanta Image Sensor operating at 1,040 frames per second, with total power consumption as low as 17 mW. It is a binary single-photon image, so if the pixel was hit by one or more photons, it is white; if not, it is black. (Source: J. Ma)

Engineers from Dartmouth’s Thayer School of Engineering have produced a new imaging technology that may revo­lutionize medical and life sciences research, security, photo­graphy, cinema­tography and other appli­cations that rely on high quality, low light imaging. The Quanta Image Sensor, or QIS, enables highly sensitive, more easily mani­pulated and higher quality digital imaging than is currently available, even in low light situa­tions, according to Eric R. Fossum, professor of engi­neering at Dartmouth. Fossum also invented the CMOS image sensor found in nearly all smart­phones and cameras across the world today.

The new QIS tech­nology is able to reliably capture and count the lowest level of light, single photons, with resolution as high as one megapixel and as fast as thousands of frames per second. Plus, the QIS can accomplish this in low light, at room tempera­ture and while using main­stream image sensor technology. Previous tech­nology required large pixels or cooling to low tempera­tures or both.

For cinemato­graphers, the QIS will enable IMAX-quality video in an easily edited digital format while still providing many of the same charac­teristics of film. For astro­physicists, the QIS will allow for the detection and capture of better signals from distant objects in space. And for life science researchers, the QIS will provide improved visua­lization of cells under a microscope, which is critical for deter­mining the effec­tiveness of therapies.

Building this new imaging capa­bility in a commer­cially accessible, inex­pensive process is important, said Fossum, so he and his team made it compa­tible with the low cost and mass produc­tion of today’s CMOS image sensor technology. They also made it readily scalable for higher reso­lution, with as many as hundreds of mega­pixels per chip. “That way it’s easier for industry to adopt it and mass produce it,” said Fossum. “The QIS is a revo­lutionary change in the way we collect images in a camera,” said Jiaju Ma, Saleh Masoo­dian and researcher Dakota Starkey. Ma and Masoo­dian received their PhDs in electrical and elec­tronics engi­neering from Thayer and are co-inven­tors of the QIS with Fossum.

The QIS platform tech­nology is unique, according to Ma, because the sensor incor­porates “Jots”, named by the research team for very small pixels, which are sensitive enough to detect a single photon of light. With this combi­nation, the QIS captures data from every single photon, or particle of light, enabling extremely high quality, easily mani­pulated digital imaging, as well as computer vision and 3-D sensing, even in low light conditions.

While the current QIS reso­lution is one megapixel, the team’s goal is for the QIS to contain hundreds of millions to billions of these jots, all scanned at a very fast rate, said Ma. Earlier this year, Masoo­dian, Ma and Fossum co-founded the startup company Gigajot Tech­nology to further develop and apply the techno­logy to a number of promising appli­cations. (Source: Dartmouth Col.)

Reference: J. Ma et al.: Photon-number-resolving megapixel image sensor at room temperature without avalanche gain, Optica 4, 1474 (2017). DOI: 10.1364/OPTICA.4.001474

Link: Thayer School of Eng., Dartmouth Col., Hanover, USA

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