Subwavelength-thick lenses with high numerical apertures and large efficiency based on high-contrast transmitarrays

Flat optical devices thinner than a wavelength promise to replace conventional free-space components for wavefront and polarization control. Transmissive flat lenses are particularly interesting for applications in imaging and on-chip optoelectronic integration. Several designs based on plasmonic metasurfaces, high-contrast transmitarrays and gratings have been recently implemented but have not provided a performance comparable to conventional curved lenses. Here we report polarization-insensitive, micron-thick, high-contrast transmitarray micro-lenses with focal spots as small as 0.57 λ. The measured focusing efficiency is up to 82%. A rigorous method for ultrathin lens design, and the trade-off between high…

• UD
  U.S. Department of Energy

  Awards: DE-SC0001293, SC0001293
• CI
  California Institute of Technology
• JS
  Japan Student Services Organization
• DA
  Defense Advanced Research Projects Agency
• OO
  Office of Science

  Award: DE-SC0001293
• KN
  Kavli Nanoscience Institute, California Institute of Technology
• BE
  Basic Energy Sciences

  Award: DE-SC0001293