A group of researchers from Princeton University and University of Washington in the United States (US) have developed a new camera sensor that is the size of a coarse grain of salt. The researchers call this a nano-optic imager, and it consists of 1.6 million cylindrical posts laid on a surface. It works exactly like a camera sensor, but takes much less space as compared to alternatives. Each of the cylindrical posts works as an optical antenna, which takes in light. The sensors then use artificial intelligence (AI) algorithms that take in all this information to create high quality images in full colours.
Other than the size, the primary difference between these sensors and traditional camera sensors is the surface that takes in the light. While traditional sensors use a combination of plastic and glass lenses in order to collect light, the nano-sensors use what is called a metasurface, which is sort of like a really thin film.
“Nano-optic imagers that modulate light at sub-wavelength scales could enable new applications in diverse domains ranging from robotics to medicine. Although metasurface optics offer a path to such ultra-small imagers, existing methods have achieved image quality far worse than bulky refractive alternatives, fundamentally limited by aberrations at large apertures and low f-numbers,” a summary of the research in scientific journal, Nature, said.
The metasurface is made of silicon nitride, which is easily available and allows such sensors to be produced at scale. The researchers devised the signal algorithm that will help produce the final image, and differs significantly from what is used in traditional cameras. “We devise a fully differentiable learning framework that learns a metasurface physical structure in conjunction with a neural feature-based image reconstruction algorithm,” the researchers wrote.
They also developed the design of the cylindrical posts in a way to ensure that the sensors could accommodate full colour photos.
The main idea behind these smaller sensors though is not to create smartphone cameras, though it’s not clear why they couldn’t be used in phones and tablets too. Instead, the nano-sensors are meant for robots, and especially those used for surgery and other healthcare applications.