US Patent 10042091 Holey optical device

A planar optical device, comprised of sets of nanometer-scale holes milled into a thin metal or ceramic film of subwavelength thickness serves to form arbitrary waveform of light. The holes form a pattern, preferrably rings, of various sizes in order to achieve a given phase front of light due to photonic effect. When designed as a lens, the device focuses incident light into a tight focal spot. In symmetric design, the focusing property of the device does not depend on the incident polarization angle. The lens can be manufactured based on high-throughput fabrication methods and easily integrated with a chip or placed at the end of an optical fiber.