Harvard School of Engineering and Applied Sciences researchers developed an ultra-thin, completely flat lens made of a glass substrate and tiny, light-concentrating silicon antennas. Color correction is achieved in the single, miniaturized device.

Light shining on the "achromatic metasurface" lens bends instantaneously, rather than gradually, while passing through. The bending effects can be designed in advance, by an algorithm, and fine-tuned to fit specific applications.

With no need to increase the lens thickness and footprint, the optical technology compensates for wavelength differences and produces a consistent effect — for example, deflecting three beams of different colors by the same angle, or focusing those colors on a single spot.

The model uses a dielectric material rather than a metal for the nanoantennas, a change which greatly improves its efficiency and, combined with a new design approach, enables operation over a broad range of wavelengths.

The technology could be used to create new miniature optical communications devices, compact cameras, and imaging technologies.

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