Achromatic Metasurface Lens at Telecommunication Wavelengths

TLDR

Nanoscale optical resonators enable flat optical components called metasurfaces, which have demonstrated focusing without monochromatic aberrations, anomalous reflection, and large circular dichroism. The study aims to demonstrate a multiwavelength achromatic lens using an aperiodic array of coupled dielectric nanoresonators. The authors designed and fabricated an aperiodic array of coupled dielectric nanoresonators to achieve achromatic focusing across multiple wavelengths. The lens maintains a constant focal length at 1300, 1550, and 1800 nm, matching full‑wave simulations and marking a key advance toward broadband flat optical elements.

Abstract

Nanoscale optical resonators enable a new class of flat optical components called metasurfaces. This approach has been used to demonstrate functionalities such as focusing free of monochromatic aberrations (i.e., spherical and coma), anomalous reflection, and large circular dichroism. Recently, dielectric metasurfaces that compensate the phase dispersion responsible for chromatic aberrations have been demonstrated. Here, we utilize an aperiodic array of coupled dielectric nanoresonators to demonstrate a multiwavelength achromatic lens. The focal length remains unchanged for three wavelengths in the near-infrared region (1300, 1550, and 1800 nm). Experimental results are in agreement with full-wave simulations. Our findings are an essential step toward a realization of broadband flat optical elements.