Wang, LeiKruk, SergeyKoshelev, KirillKravchenko, Ivan I.Luther-Davies, BarryKivshar, Yuri2020-01-081530-6984http://hdl.handle.net/1885/196602Metasurfaces, two-dimensional lattices of nanoscale resonators, offer unique opportunities for functional flat optics and allow the control of the transmission, reflection, and polarization of a wavefront of light. Recently, all-dielectric metasurfaces reached remarkable efficiencies, often matching or out-performing conventional optical elements. The exploitation of the nonlinear optical response of metasurfaces offers a paradigm shift in nonlinear optics, and dielectric nonlinear metasurfaces are expected to enrich subwavelength photonics by enhancing substantially nonlinear response of natural materials combined with the efficient control of the phase of nonlinear waves. Here, we suggest a novel and rather general approach for engineering the wavefront of parametric waves of arbitrary complexity generated by a nonlinear metasurface. We design all-dielectric nonlinear metasurfaces, achieve a highly efficient wavefront control of a third-harmonic field, and demonstrate the generation of nonlinear beams at a designed angle and the generation of nonlinear focusing vortex beams. Our nonlinear metasurfaces produce phase gradients over a full 0-2π phase range with a 92% diffraction efficiency.The authors acknowledge a financial support from the Ministry of Education and Science of the Russian Federation (grant no. 3.1668.2017), the Australian Research Council and the Australian National University. Part of this research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. K. K. acknowledges FASIE (grant no. 10864GU/2016) for the valuable support.application/pdfen-AU© 2018 American Chemical SocietyMetasurfacesnonlinear opticsthird-harmonic generationMie resonanceswavefront control2018-05-1110.1021/acs.nanolett.8b014602019-08-25