Broadband high-efficiency dielectric metasurfaces for the visible spectrum.
Metasurfaces are planar optical elements that hold promise for overcoming the limitations of refractive and conventional diffractive optics. Original dielectric metasurfaces are limited to transparency windows at infrared wavelengths because of significant optical absorption and loss at visible wavelengths. Thus, it is critical that new materials and nanofabrication techniques be developed to extend dielectric metasurfaces across the visible spectrum and to enable applications such as high numerical aperture lenses, color holograms, and wearable optics. Here, we demonstrate high performance dielectric metasurfaces in the form of holograms for red, green, and blue wavelengths with record absolute efficiency (>78%). We use atomic layer deposition of amorphous titanium dioxide with surface roughness less than 1 nm and negligible optical loss. We use a process for fabricating dielectric metasurfaces that allows us to produce anisotropic, subwavelength-spaced dielectric nanostructures with shape birefringence. This process is capable of realizing any high-efficiency metasurface optical element, e.g., metalenses and axicons.
Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; devlin@fas.harvard.edu capasso@seas.harvard.edu.
Robert C
RC
Devlin
Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138;
Mohammadreza
M
Khorasaninejad
Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138;
Wei Ting
WT
Chen
Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; University of Waterloo, Waterloo, ON N2L 3G1, Canada.
Jaewon
J
Oh
Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; devlin@fas.harvard.edu capasso@seas.harvard.edu.
Federico
F
Capasso
hologram; metasurface; nanophotonics