Researchers from NASA's Jet Propulsion Laboratory and the California Institute of Technology have developed flat optical lenses said to be capable of manipulating light in ways that have been difficult or impossible to achieve with conventional optical devices.
The lenses are made of silicon nanopillars arranged into a honeycomb pattern. It is this 'metasurface' that allows light waves to be controlled.
"Currently, optical systems are made one component at a time and the components are often assembled manually," said Andrei Faraon, an assistant professor 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."
Each nanopillar has an elliptical cross section and, by carefully varying the size of each pillar and rotating them around their axes, the scientists could manipulate the phase and polarisation of passing light simultaneously.
"If you think of a modern microscope," Faraon noted, "it has multiple components that have to be carefully assembled inside. With our platform, we can make each of these optical components and stack them atop one another very easily using an automated process. Each component is just 1µm thick."
The lenses may also be used to modify the shape of light beams. According to the team, semiconductor lasers typically emit elliptical beams that are hard to work with. New metasurface optical components could replace expensive optical systems used to make these beams circular and allow more compact systems to be created.
Author
Graham Pitcher
Source: www.newelectronics.co.uk