What is planar optics?

Meta-lenses are an emerging technology that overcomes the limits of traditional lenses. Meta-lenses are made by arranging tiny structures on a surface. The size of the structures are about a few 100 nanometers in width and height. With the right combination of structures any optical function can be made. This means both lenses and optical components can be made or applications that were not possible before.

Meta-lenses have serious advantages compared to standard lenses:

• Meta-lenses are thinner than a hair. Standard lenses are thick and heavy.

• Spherical and other shape aberrations can be entirely removed. With “cut glass” lenses aberration corrected lenses are difficult to make and therefore expensive.

• The nano-structures can be tailored to the colours (wavelengths) that are needed. In normal lenses complicated assemblies are needed to reduce these chromatic aberations.

• Because of the improvements above lens systems like cameras, VR goggles, microscopes and telescopes will become much less complicated. This will make them lighter, less costly and better.

• Meta-lenses can be made with CMOS processes and equipment. These are the processes that are used to mass produce computer chips.

The optical nanostructures can be used for more than just making lenses. You can also make polarizers, colour filters, diffraction gratings or holograms. In those cases, the term meta-surfaces or planar optics is more appropriate.