Hu Xiao-Long, Li Fen, Xu Shi-Hang, Liu Wen-Jie
Opt Lett. 2023 Aug 1;48(15):4033-4036. doi: 10.1364/OL.497058.
Metal plasmonic nano-gratings possess a high absorption ability and exhibit potential applications in sensing, hot-electron photodetection, metasurfaces, etc. However, the fabrication techniques of high-quality nano-gratings are challenging. In this article, a binary metal micron grating for near-infrared hot-electron photodetectors (HEPDs) is designed in which the surface plasmons are excited by high-diffraction-order modes. The high-diffraction-order micron grating can be fabricated by conventional lithography and has a significantly higher tolerance in the grating parameters than a nano-grating. The range of absorption greater than 70% is ∼3 times that of a nano-grating. Moreover, an interesting relationship between the resonant wavelength and the grating duty cycle is found. When the high-diffraction-order micron grating is applied in metal-insulator-metal HEPDs, a high zero-biased responsivity of 0.533 mA/W is achieved.
金属等离子体纳米光栅具有高吸收能力，在传感、热电子光探测、超表面等方面展现出潜在应用。然而，高质量纳米光栅的制造技术具有挑战性。在本文中，设计了一种用于近红外热电子光探测器（HEPD）的二元金属微米光栅，其中表面等离子体由高衍射级模式激发。高衍射级微米光栅可通过传统光刻制造，并且在光栅参数方面比纳米光栅具有显著更高的容差。吸收率大于70%的范围约为纳米光栅的3倍。此外，还发现了共振波长与光栅占空比之间的有趣关系。当将高衍射级微米光栅应用于金属-绝缘体-金属热电子光探测器时，实现了0.533 mA/W的高零偏置响应率。
