Wu Jun, Sun Yasong, Wu Feng, Wu Biyuan, Wu Xiaohu
College of Electrical Engineering, Anhui Polytechnic University, Wuhu, 241000, China.
Basic Research Center, School of Power and Energy, Northwestern Polytechnical University, Xi'an 710064, Shaanxi, China.
Beilstein J Nanotechnol. 2022 Jul 19;13:675-681. doi: 10.3762/bjnano.13.59. eCollection 2022.
A tunable graphene absorber, composed of a graphene monolayer and a substrate spaced by a subwavelength dielectric grating, is proposed and investigated. Strong light absorption in the graphene monolayer is achieved due to the formation of embedded optical quasi-bound states in the continuum in the subwavelength dielectric grating. The physical origin of the absorption with high quality factor is examined by investigating the electromagnetic field distributions. Interestingly, we found that the proposed absorber possesses high spatial directivity and performs similar to an antenna, which can also be utilized as a thermal emitter. Besides, the spectral position of the absorption peak can not only be adjusted by changing the geometrical parameters of dielectric grating, but it is also tunable by a small change in the Fermi level of the graphene sheet. This novel scheme to tune the absorption of graphene may find potential applications for the realization of ultrasensitive biosensors, photodetectors, and narrow-band filters.
提出并研究了一种由石墨烯单层和由亚波长介质光栅隔开的衬底组成的可调谐石墨烯吸收器。由于在亚波长介质光栅中形成了连续统中的嵌入式光学准束缚态，石墨烯单层中实现了强光吸收。通过研究电磁场分布来考察具有高品质因数吸收的物理起源。有趣的是，我们发现所提出的吸收器具有高空间方向性，并且表现得类似于天线，它也可以用作热发射器。此外，吸收峰的光谱位置不仅可以通过改变介质光栅的几何参数来调节，而且还可以通过石墨烯片费米能级的微小变化来调谐。这种调节石墨烯吸收的新颖方案可能会在实现超灵敏生物传感器、光电探测器和窄带滤波器方面找到潜在应用。
