Researchers Unveil a Novel Color-Coding 3D Light-Field Sensor with Stunning Resolution
Coding the angle of incoming light rays — or X-rays — by color, this sensor can scale down to an angular resolution of 0.0018°.
Researchers from the National University of Singapore (NUS) and Tianjin University have come up with a new light-field sensor which, they say, can create 3D images with an angular resolution as fine as 0.0018° — and can even extend into X-ray frequencies.
"Currently, light-field detectors use an array of lenses or photonic crystals to obtain multiple images of the same space from many different angles. However, integrating these elements into semiconductors for practical use is complicated and costly," claims Liu Xiaogang, professor in the NUS department of chemistry. "Conventional technologies can detect light fields only in the ultraviolet to visible light wavelength range, leading to limited applicability in X-ray sensing."
The team's work, by contrast, extends its spectral response from 0.002nm to 550nm — meaning it can be used in X-ray imaging — and offers a wide angular measurement range over 80° with a resolution as fine as 0.0018° — enough to produce highly detailed 3D images across a wide portion of the light spectrum.
The prototype sensor is built around inorganic perovskite nanocrystals, patterned onto a transparent thin-film substrate and integrated into a charge-coupled device (CCD) sensor. Light hitting the sensor excites the nanocrystals, which causes the perovskite to emit its own light — varying in color depending on the angle of incoming light, allowing the CCD to capture angle data.
"A single angle value, however, is not enough to determine the absolute position of the object in a three-dimensional space," notes Yi Luying, PhD and first author of the paper. "We discovered that adding another basic crystal converter unit perpendicular to the first detector and combining it with a designed optical system could provide even more spatial information regarding the object in question."
The resulting prototype imaging system proved capable of capturing detailed 3D images of objects as far away as five feet — something which could be of use in autonomous vehicles for better capturing details about their surrounding environment. The team is now working on improving the sensor's spatial accuracy and resolution still further — and has applied for a patent ahead of commercialization.
The team's work has been published under open-access terms in the journal Nature.