Metasurface flat optics: from high-performance components to cameras

Metasurfaces are leading to the emergence of new optical components based on dispersion engineering of nanoscale structures, which enable circumventing the limitations of standard refractive and diffractive optics as well as entirely new functionalities. Broadband metasurface achromatic optics based on metasurface and on hybrid refractive/diffractive design will be presented, along with ultracompact spectrometers consisting of a single off axis metalens, where high resolution is achieved by designing chromatic dispersion and eliminating field curvature. New metaoptical components where different functionalities can be accessed by changing either the wavelength, the angle of incidence or the incidence polarization will be presented. As an example, using waveplates with designed arbitrary elliptical birefringence, the eigen-polarizations and the output polarization can be tuned continuously from linear to elliptical by changing the angle of incidence. A new approach to polarization optics will be presented, based on a powerful generalization of Fourier optics ( Matrix Fourier Optics), which leads to the replacement of conventional phase plates and analyzers, This has led to the demonstration of a compact, single shot, full Stokes polarization sensitive camera using a single metasurface, thus dramatically reducing the complexity of existing cameras and increasing their functionality. Finally taking inspiration from how jumping spiders capture their prey, a new depth sensing camera at video rates based on co-design of hardware (metalenses) and software, which requires far computational resources than stereo and time of flight cameras has been developed. It combines spatially multiplexed metalenses and efficient computations to measure depth from image defocus. Compared with previous passive artificial depth sensors, this bioinspired design is lightweight, single-shot, and requires much less computation.