We show theoretically that coherent perfect absorption (CPA) of light is possible by a graphene monolayer without doping. To achieve the CPA, undoped graphene is embedded inside a multilayer structure called mirror structure, which increases the effective impedance of the surrounding medium. The increased effective impedance allows the destructive interference of light outside the structure that induces an increased Joule heat generating perfect absorption of light by graphene. We find that the CPA is possible for any wavelength as long as the thickness of each layer of the structure is a quarter of the corresponding wavelength. By changing the incident wavelength, but keeping the thickness of each layer, we show that the optical absorption is sensitive to the change of the incident wavelength. Therefore, we can design a photo detector for a specific wavelength.

中文翻译：

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未掺杂石墨烯单层对光的相干完美吸收

我们从理论上证明，单层石墨烯可以实现光的相干完美吸收（CPA），而无需兴奋剂。为了实现 CPA，未掺杂的石墨烯被嵌入称为镜面结构的多层结构内，这增加了周围介质的有效阻抗。增加的有效阻抗允许结构外部的光发生破坏性干扰，从而引起焦耳热增加，从而使石墨烯完美吸收光。我们发现，只要结构每层的厚度是相应波长的四分之一，CPA 对于任何波长都是可能的。通过改变入射波长，但保持每层的厚度，我们表明光学吸收对入射波长的变化敏感。因此，我们可以设计针对特定波长的光电探测器。