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We propose an original technique for the grating metasurfaces fabrication by low-power ultraviolet laser treatment of fluorinated graphene (FG) films with the focus on terahertz applications. The laser treatment reduces dielectric FG to its conductive counterparts, increasing DC conductivity to 170 S·m−1 for treated areas. The electromagnetic response of the grating metasurfaces studied by THz time-domain spectroscopy in the 100 GHz–1 THz frequency range demonstrates enhanced resonant transmittance through metasurfaces. The intensity and position of transmittance peak could be tuned by changing the metasurface geometry, i.e. the period of the structure and width of the reduced and unreduced areas. In particular, the decrease of the reduced FG area width from 400 to 170 μ m leads to the shift of the resonance peak from 0.45 THz to the higher frequencies, 0.85 THz. Theoretical description based on the multipole theory supported by finite element numerical calculations confirms the excitation of the dark state in the metasurface unit cells comprising reduced and unreduced FG areas at resonance frequency determined by the structure geometrical features. Fabricated metasurfaces have been proved to be efficient narrowband polarizers being rotated by 50° about the incident THz field vector. [ABSTRACT FROM AUTHOR]

The dependence of transmission/absorption of terahertz (THz) radiation on strain in graphene is investigated experimentally and with the aid of ab initio calculations. By applying strain to chosen graphene layer(s), the effective sheet conductance can be fine‐tuned to necessary value to design tunable passive THz components (such as shields, filters, polarizers, etc.) utilizing the high absorption ability of graphene. The positive influence of non‐perfectness of chemically vapor deposited (CVD) graphene for strong tunability versus mechanical deformations is also discussed. [ABSTRACT FROM AUTHOR]