Laser Constructing Short‐Range Disordered Metagratings for Visible Near‐Infrared Polarization‐Independent Absorption

Subwavelength-structured metasurfaces working in visible and near-infrared bands present a high challenge in large-scale device fabrication. In this study, a scalable, high-efficient, and low-cost laser-induced nanopatterning technique is exploited to fabricate a kind of short-range disordered metagratings, which enables broadband polarization-independent absorption in the visible to near-infrared wavelength. The short-range disorder of the laser-induced nanogratings originates from the laser-induced thermal effect and can be spontaneously organized during laser nanopatterning. The unique disorder can break the unidirectional characteristics of the nanogratings, which empowers the metagratings to excite coupled resonance modes. This helps to achieve near-perfect absorption in the visible to near-infrared band (400-1100 nm) with an excellent angular tolerance (up to 60 degrees) and average absorptivities of 96.3% and 93.5% under the TM and TE modes, respectively. These low-cost metagratings can potentially inspire wide applications in the fields of solar cells, sensing, and thermal emitters.