Mini polarisation camera heralds new imaging applications 

Published in Science, the work details how the team used metasurfaces - nanoscale structures that interact with light at wavelength size-scales - to capture the polarisation. Current devices that produce similar results are bulky and expensive, but the Harvard device is about the size of a thumb. This means it could conceivably be installed in a smartphone, assisting in applications varying from machine vision and atmospheric chemistry to detecting objects that are camouflaged.  

"If we want to measure the light's full polarisation state, we need to take several pictures along different polarisation directions," said first author Noah Rubin, from Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS). 

"Previous devices either used moving parts or sent light along multiple paths to acquire the multiple images, resulting in bulky optics. A newer strategy uses specially patterned camera pixels, but this approach does not measure the full polarisation state and requires a non-standard imaging sensor. In this work, we were able to take all of the optics needed and integrate them in a single, simple device with a metasurface."