這篇論文以探討石墨烯的特性與模擬利用石墨烯在中紅外線範圍達到完全吸收，石墨烯的能帶結構特殊，其電導率可以分為intra-band和inter-band兩部分，由於inter-band是複數形式的對數函數，這類函數無法直接帶入FDTD模擬方法，因此本實驗室發展了一套近似法，擬合出可以帶入FDTD運算的石墨烯inter-band模型，同時驗證該模型的正確性，接著討論達到完全吸收的三種方法，但這篇論文僅深入討論前兩種方法，第一種方法礙於單層石墨烯的吸收效果有限，因此用薄層金屬去模擬驗證，確認在符合特定條件下可以達到完全吸收的效果，接著第二種方法利用前面提出的石墨烯電導率擬合模型，模擬單層石墨烯在特定條件下實現強吸收與完全吸收的效果，同時也發現這種方法的限制，因此最後改變結構用週期性的石墨烯做完全吸收，驗證在特定條件下，這種結構在中紅外線可以達到近乎完全吸收的效果。

This thesis analyzes the possibility of using graphene to achieve total absorption in the mid-infrared. The auxiliary differential equation method is developed to model the broadband conductivity of graphene in FDTD. Three different methods to achieve total absorption in general are first discussed. The first method of using coherent perfect absorption is analyzed with single metallic layer. It requires that the real and imaginary part of the refractive index are equal. This condition is difficult to be achieved in graphene. The second method of using thin film and PEC Fabry-Perot cavity is analyzed. By applied certain gated voltage, a single graphene sheet with PEC FP cavity can achieve nearly perfect absorption at a particular wavelength. Furthermore, by replace graphene sheet with periodic graphene nanoribbon structure, perfect absorption peak can be tuned.

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