US Patent 10408419 Lighting device including a collimating metalens

Lighting devices including metalenses are disclosed. In some embodiments, the metalenses are in the form of a hybrid multi-region collimating metalens that includes a first region and a second region, wherein the hybrid multi-region collimating metalens is configured to collimate (e.g., visible) light incident thereon. In some instances the first region includes an array of first unit cells that contain sub-wavelength spaced nanostructures, such that the first region functions as a sub-wavelength high contrast grating (SWHCG), whereas the second region includes an array of second unit cell, wherein the array of second unit cells includes a near periodic annular arrangement of nanostructures such that the second region approximates the functionality of a locally periodic radial diffraction grating.