Angle- and polarization-adaptive aperiodic-anisotropic metasurfaces for broadband reflectance suppression.

Authors

Jeongbin Yoon, Mingwan Cho, Hyeonhee Kim, Hyeonjin Park, In-Sung Joe, Jonghwa Shin

Published in

iScience. Volume 29. Issue 8. Pages 116833. Aug 21, 2026. Epub Jul 17, 2026.

Abstract

Optical reflectance at the air-silicon interface degrades CMOS image sensor (CIS) performance, causing signal loss and image artifacts. Conventional single-layer anti-reflective coatings (1-ARCs) offer CMOS-compatible simplicity, but their isotropic nature and limited spatial tunability make them poorly suited to handle angle- and polarization-dependent characteristics of incident light, particularly where the chief-ray angle varies across the sensor surface. Here, we present an aperiodic-anisotropic metasurface (AAM) composed of subwavelength TiO₂ nanodisks with spatially varying geometric anisotropy, enabling broadband, angle- and polarization-resolved impedance matching tailored to local incidence conditions. Its performance was verified through unit-cell-level optimization and further validated by full-area simulations on a 20 × 20 μm² Si substrate under Gaussian beam illumination, where the AAM achieved ∼1.40% average reflectance across 400-700 nm for both polarizations, outperforming conventional 1-ARC and double-layer anti-reflective coating (2-ARC). This offers a practical solution for CIS and other systems such as LiDAR (light detection and ranging) receivers under spatially varying illumination.

PMID:
42502409
Bibliographic data and abstract were imported from PubMed on 26 Jul 2026.

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