Imagine you need to have a copy of an object. You take a snapshot with your smartphone, send it to your 3D printer, and within minutes you have a replica accurate to within microns of the original. That’s what a tiny new high-resolution 3D imager called a “nanophotonic coherent imager” (NCI) could achieve.
The NCI provides the highest depth-measurement accuracy of any such nanophotonic 3D imaging device, using an inexpensive silicon chip less than a millimeter square in size, says Ali Hajimiri, the Thomas G. Myers Professor of Electrical Engineering in the Caltech Division of Engineering and Applied Science, who heads the research. While 3D imaging systems are available, the most sensitive ones are too large and expensive to be used in consumer applications.
In a regular camera, each pixel represents the intensity of the light received from a specific point in the image, which could be near or far from the camera, meaning that the pixels provide no information about the relative distance of the object from the camera.
In contrast, each pixel in an image created by the NCI provides both distance and intensity information. “Each pixel on the chip is an independent interferometer, an instrument that uses the interference of light waves to make precise measurements, which detects the phase and frequency of the signal in addition to the intensity,” says Hajimiri.