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Terahertz radiation enhancement based on LT-GaAs by optimized plasmonic nanostructure
Laser Physics ( IF 1.2 ) Pub Date : 2021-02-05 , DOI: 10.1088/1555-6611/abd935
Rui Jiang 1 , Shuang Cheng 1 , Quanyong Li 1, 2 , Qishu Wang 1 , Yinjie Xin 1
Affiliation  

Terahertz waves have unique penetrability, safety, spectral resolution, and many other useful properties. Therefore, terahertz waves are widely employed in medical treatment, detection, imaging, security, and spectroscopy. They also possess great development prospects in photoconductive antennas (PCAs) for telecommunication and other devices. However, terahertz PCAs are still limited by the weak photocurrents and small light absorption rates, making the development of PCAs with improved conversion efficiencies highly desirable. In this study, a new type of plasmonic PCAs with high photoelectric conversion efficiency was proposed. The interaction between the 800 nm fs laser and staggered nanorods was studied by the finite difference time domain (FDTD) method. The geometric parameters of the nanorods arrays were optimized. Compared to conventional photoconductive antennas without nanostructures, the PCAs with optimized nano-plasmonic structure I showed threefold higher electric field radiations under 800 nm fs laser irradiation. Optimized plasmonic nanostructure II increases photocurrent up to 335.553 nA that indicates 10 times enhancement in comparison with conventional structure. Hence, the developed structures greatly enhanced the light absorption of the photosensitive layer based on low-temperature-grown gallium arsenide. In sum, the proposed staggered hexagonal plasmonic structures (structure II) could effectively improve the light-terahertz conversion efficiencies of PCAs.



中文翻译:

优化的等离子体纳米结构增强了基于LT-GaAs的太赫兹辐射

太赫兹波具有独特的渗透性,安全性,光谱分辨率和许多其他有用的特性。因此,太赫兹波被广泛用于医疗,检测,成像,安全性和光谱学。它们在电信和其他设备的光电导天线(PCA)中也具有广阔的发展前景。但是,太赫兹PCA仍然受到弱光电流和小的光吸收率的限制,因此非常需要开发具有提高的转换效率的PCA。本研究提出了一种新型的光电转换效率高的等离子体PCA。采用时差有限差分法(FDTD)研究了800nm fs激光与交错纳米棒之间的相互作用。优化了纳米棒阵列的几何参数。与不具有纳米结构的常规光电导天线相比,具有优化的纳米等离子体结构I的PCA在800 nm fs激光辐照下显示出高出三倍的电场辐射。优化的等离子纳米结构II可将光电流增加至335.553 nA,这表明其与常规结构相比提高了10倍。因此,显影的结构大大增强了基于低温生长的砷化镓的感光层的光吸收。总之,提出的交错六边形等离激元结构(结构II)可以有效地提高PCA的光太赫兹转换效率。优化的等离子纳米结构II可将光电流增加至335.553 nA,这表明其与常规结构相比提高了10倍。因此,显影的结构大大增强了基于低温生长的砷化镓的感光层的光吸收。总之,提出的交错六边形等离激元结构(结构II)可以有效地提高PCA的光太赫兹转换效率。优化的等离子纳米结构II可将光电流增加至335.553 nA,这表明其与常规结构相比提高了10倍。因此,显影的结构大大增强了基于低温生长的砷化镓的感光层的光吸收。总之,提出的交错六边形等离激元结构(结构II)可以有效地提高PCA的光太赫兹转换效率。

更新日期:2021-02-05
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