Zhang Ye, Meng Dejia, Li Xiao, Yu Honghao, Lai Jianjun, Fan Zhaoyang, Chen Changhong
Opt Express. 2018 Nov 12;26(23):30862-30872. doi: 10.1364/OE.26.030862.
Here, we present a graphene-based long-wavelength infrared photodetector, for enhancing the infrared absorption of which the design consists of magnetic- and electric-plasmon resonators of metasurface to excite the graphene surface-plasmonic polaritons (SPPs). Through tuning the graphene Fermi energy to achieve the distinct resonances in a matching frequency, peak graphene absorbance exceeding 67.2% is confirmed, even when a lossy dielectric is used, and the field angle of view is up to 90°. If the graphene is of a different carrier mobility, then the absorption frequency is lockable, and the device always can keep the system absorbance close to 100 percent. The significantly enhanced graphene absorbance, up to ~29-fold that of a suspended graphene (general 2.3%), is attributed to the surface-plasmonic coupling between the magnetic and the electric resonances, as well as Fabry-Pérot interference of the coherent SPPs. The plasmonic cavity-mode model and equivalent-circuit method developed in this study will also be useful in guiding other optoelectronic device design.
在此，我们展示了一种基于石墨烯的长波长红外光电探测器，为增强其红外吸收，该设计由超表面的磁等离子体和电等离子体谐振器组成，用于激发石墨烯表面等离子体激元（SPP）。通过调节石墨烯费米能量以在匹配频率上实现明显的谐振，即使使用有损电介质，也证实了石墨烯的峰值吸收率超过67.2%，并且视场角高达90°。如果石墨烯具有不同的载流子迁移率，那么吸收频率是可锁定的，并且该器件总能使系统吸收率接近100%。石墨烯吸收率显著增强，高达悬浮石墨烯（通常为2.3%）的约29倍，这归因于磁谐振和电谐振之间的表面等离子体耦合以及相干SPP的法布里 - 珀罗干涉。本研究中开发的等离子体腔模模型和等效电路方法也将有助于指导其他光电器件设计。
