2020/08/04 by Fatih Balli, Mansoor A. Sultan, Sarah K. Lami +1 · 1 voice · 8 citations
Materials Science · Physics and Astronomy · #Metamaterials and Metasurfaces Applications #Optical Coatings and Gratings #Photonic Crystals and Applications
paper · pdf · doi:10.1038/s41467-020-17646-y
openalex publication_date 2020/08/04 · openalex created_date 2020/08/10 · openalex updated_date 2026/07/31
Metalenses, ultra-thin optical elements that focus light using subwavelength structures, have been the subject of a number of recent investigations. Compared to their refractive counterparts, metalenses offer reduced size and weight, and new functionality such as polarization control. However, metalenses that correct chromatic aberration also suffer from markedly reduced focusing efficiency. Here we introduce a Hybrid Achromatic Metalens (HAML) that overcomes this trade-off and offers improved focusing efficiency over a broad wavelength range from 1000-1800 nm. HAMLs can be designed by combining recursive ray-tracing and simulated phase libraries rather than computationally intensive global search algorithms. Moreover, HAMLs can be fabricated in low-refractive index materials using multi-photon lithography for customization or using molding for mass production. HAMLs demonstrated diffraction limited performance for numerical apertures of 0.27, 0.11, and 0.06, with average focusing efficiencies greater than 60% and maximum efficiencies up to 80%. A more complex design, the air-spaced HAML, introduces a gap between elements to enable even larger diameters and numerical apertures.