Evolutionary algorithms for designing metalenses

The paper describes an evolutionary algorithm based method for the rapid design of efficient metasurface flat-optics lenses (metalens). Current design methods based on the local-phase approach suffer from reduced efficiency, particularly, towards the edges of the lenses. The shortcomings of the local-phase approach can be addressed by resorting to extended unit-cells. We have recently reported on evolutionary approaches [1] that are helpful in designing such extended unit-cells. The work on beam-deflecting metasurfaces using extended unit-cells reported earlier is extended here to the design of an entire metalens composed of many such beam-deflectors.