Metasurface Flat Lens DevelopedCategory: Science & Technology
Posted: August 27, 2012 06:21AM
When light enters a material, like glass or water, its speed changes which causes the light to bend, and depending on the shape of the material, that bending can be used for different effects. The light can be focused to a single point or dispersed across a larger area, which is useful for a myriad of purposes, including communications. Unfortunately the bending of the light by a lens can cause distortions, such as the 'fisheye' distortion, and these distortions can degrade the image. For photography and telecommunications these distortions can be an issue and now researchers at the Harvard School of Engineering and Applied Sciences have designed a new kind of lens without any distortion.
Metamaterials are manmade materials with special internal structures that give them properties impossible in nature. For example, a metamaterial can bend light backwards; relative to the direction natural materials would bend it. What the researchers made was a metasurface, because at just 60 nm thick, it is nearly two dimensional. This surface has a silicon base with gold antennas at special angles in certain shapes to affect the light similarly to a traditional lens, but instantaneously instead of through the thickness of the material. This prevents there from being any distortion to the light.
This metasurface approach can potentially be used to shrink and enhance any bulky optical system down to a much smaller size. It may even allow for new optical systems to be developed that are impossible with traditional lenses.