Subwavelength resolution imaging by ultra-thin meta-lens

We demonstrate high numerical aperture (NA=0.8) transmissive metasurface-based lenses with efficiencies as high as 86% in the visible spectrum. Meta-lenses allow diffraction-limited focusing at red (λ=660 nm), green (λ=532 nm), and blue (λ=405 nm) wavelengths. They can resolve nanoscale features with sub-wavelength gaps.