Xu Yanli, Li Hongxu, Zhang Xin, Bai Zhongchen, Zhang Zhengping, Qin Shuijie
Appl Opt. 2020 Oct 1;59(28):9003-9009. doi: 10.1364/AO.405225.
Black phosphorus (BP) is an important two-dimensional material that plays a key role in new photoelectric devices. In this work, a triple-band BP-based absorber was proposed, in which a monolayer BP is coupled with the missing angle rectangular structure. Due to the critical coupling of the guided resonance, the BP absorber achieves a triple-band absorption. The results showed that the absorption spectra at 2901.76 nm, 3810.71 nm, and 4676.97 nm under TM polarization achieve a high absorption of 95.45%, 98.68%, and 98.06%, respectively. In addition, the absorption peak and resonance wavelength can be flexibly adjusted by the electron doping of BP, the geometrical parameters of the structure, and the refractive index of the dielectric substrate. Because of the anisotropy properties of BP, the structure exhibits polarization-dependent absorption characteristics. Thus, the missing angle rectangular structure will provide a potential to design mid-infrared absorbers and shows a significant practical application in many photoelectric devices such as photodetectors, modulators, and optical switches.
黑磷（BP）是一种重要的二维材料，在新型光电器件中起着关键作用。在这项工作中，提出了一种基于黑磷的三波段吸收器，其中单层黑磷与缺角矩形结构耦合。由于导模共振的临界耦合，该黑磷吸收器实现了三波段吸收。结果表明，在TM偏振下，2901.76 nm、3810.71 nm和4676.97 nm处的吸收光谱分别实现了95.45%、98.68%和98.06%的高吸收。此外，通过黑磷的电子掺杂、结构的几何参数和介电衬底的折射率，可以灵活调节吸收峰和共振波长。由于黑磷的各向异性特性，该结构表现出偏振依赖的吸收特性。因此，缺角矩形结构将为设计中红外吸收器提供潜力，并在许多光电器件如光电探测器、调制器和光开关中显示出重要的实际应用价值。
