A new optical device made of silicon “nanopillars” could lead to advanced microscopes, displays, sensors, and cameras that can be mass-produced using the same techniques used to manufacture computer microchips.
“Currently, optical systems are made one component at a time, and the components are often manually assembled,” says Andrei Faraon, an assistant professor of applied physics and materials science at Caltech. “But this new technology is very similar to the one used to print semiconductor chips onto silicon wafers, so you could conceivably manufacture millions of systems such as microscopes or cameras at a time.”
Seen under a scanning electron microscope, the new metasurfaces that the team created resemble a cut forest where only the stumps remain. Each silicon stump, or pillar, has an elliptical cross section, and by carefully varying the diameters of each pillar and rotating them around their axes, the scientists were able to simultaneously manipulate the phase and polarization of passing light.
Light is an electromagnetic field, and the field of single-color, or monochromatic, light oscillates at all points in space with the same frequency but varying relative delays, or phases. Manipulating this relative delay, or phase, influences the degree to which a light ray bends, which in turn influences whether an image is in or out of focus.
