We fabricate all-inorganic, high refractive index optics, including metalenses, waveguides, and diffractive optical elements via nanoimprint lithography with TiO2 nanoparticle dispersion inks and report full-wafer fabrication of visible wavelength metalenses with absolute focusing efficiencies greater than 80% (>95% of design efficiency). 3-D metal oxide log-piles are possible via direct NIL using sequential imprint, planarization, imprint cycles followed by removal of the sacrificial planarization layers. 3-D metal log-piles are possible via metallization of imprinted 3-D sacrificial templates. Several examples will be discussed.
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