High numerical aperture meta-lenses at visible wavelengths Khorasaninejad, M. Chen, W. T. Zhu, A. Oh, J. Roques-Carmes, Charles Mishra, I. Devlin, R. C. Capasso, F. We report high numerical aperture meta-lenses in the visible spectrum with focal spots as small as 0.65λ. Meta-lenses are based on ultra-thin titanium dioxide metasurface phase masks. They operate in transmission mode and are polarization-insensitive. Optica Publishing Group 2016 info:eu-repo/semantics/conferenceObject doc-type:ConferenceObject ConferenceObject http://purl.org/coar/resource_type/c_5794 https://research-explorer.ista.ac.at/record/21635 Khorasaninejad M, Chen WT, Zhu A, et al. High numerical aperture meta-lenses at visible wavelengths. In: <i>Frontiers in Optics 2016</i>. Optica Publishing Group; 2016. doi:<a href="https://doi.org/10.1364/fio.2016.jw4a.63">10.1364/fio.2016.jw4a.63</a> eng info:eu-repo/semantics/altIdentifier/doi/10.1364/fio.2016.jw4a.63 info:eu-repo/semantics/altIdentifier/e-isbn/9781943580194 info:eu-repo/semantics/altIdentifier/issn-l/2162-2701 info:eu-repo/semantics/closedAccess