We propose an ultrathin perfect absorber for normal incident waves using a Dirac cone metasurface with the thickness of 1/38 free-space wavelength. First, we prepare Dirac cone metasurfaces consisting of periodic metallic chain patterns on a dielectric substrate having the Γ-point frequencies of approximately 30 GHz. The perfect absorber is designed by adjusting the external coupling of the Dirac cone metasurfaces with their chain densities. Based on the one-port resonator model, we clarify that the perfect absorber is realized at the critical coupling condition with identical internal and external Q-factors. We experimentally demonstrate a perfect absorption with the reflectance as small as -37 dB by the metasurface with the critical external coupling.

中文翻译：

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使用具有临界外部耦合的狄拉克锥超表面的超薄完美吸收器，用于正常入射波


我们提出了一种使用厚度为 1/38 自由空间波长的狄拉克锥超表面的超薄完美吸收器，用于正常入射波。首先，我们在介电基板上制备由周期性金属链图案组成的狄拉克锥超表面，其 Γ 点频率约为 30 GHz。通过调整狄拉克锥超表面的外部耦合及其链密度来设计完美的吸收器。基于单端口谐振器模型，我们阐明完美的吸收器是在具有相同的内部和外部 Q 因子的临界耦合条件下实现的。我们通过实验证明了具有临界外部耦合的超表面的完美吸收，反射率小至-37 dB。