Xiao Peng, Tu Xuecou, Kang Lin, Jiang Chengtao, Zhai Shimin, Jiang Zhou, Pan Danfeng, Chen Jian, Jia Xiaoqing, Wu Peiheng
School of Electronic Science and Engineering, Nanjing University, Nanjing, 210023, China.
Sci Rep. 2018 May 23;8(1):8032. doi: 10.1038/s41598-018-26204-y.
A reflective grating-coupled structure on the silicon substrate was designed to improve the detection efficiency of terahertz detectors for the frequency ranging from 0.26 THz to 0.36 THz. By using finite difference time domain (FDTD) solutions, the simulation and optimized design of the grating-coupled structure were carried out. The results showed that the signal was effectively reflected and diffracted by the reflective grating-coupled structure which significantly enhanced the electric field in the place of the detector. The maximum electric field can be increased by 2.8 times than that of the Fabry-Perot resonator. To verify the design results, the reflective grating-coupled structure was applied in the preparation of the NbN array detector chip and compared with the NbN array detector chip with the F-P resonator. The results showed that the maximum voltage responsivity of the NbN detector with the reflective grating-coupled structure was 2 times larger than the NbN detector with the F-P resonator. It indicates that the reflective grating-coupled structure can efficiently improve the detection efficiency of THz detectors.
设计了一种硅衬底上的反射光栅耦合结构，以提高太赫兹探测器在0.26太赫兹至0.36太赫兹频率范围内的探测效率。利用时域有限差分（FDTD）解法，对光栅耦合结构进行了模拟和优化设计。结果表明，反射光栅耦合结构有效地反射和衍射了信号，显著增强了探测器位置处的电场。最大电场比法布里-珀罗谐振器的电场可提高2.8倍。为验证设计结果，将反射光栅耦合结构应用于NbN阵列探测器芯片的制备，并与具有F-P谐振器的NbN阵列探测器芯片进行比较。结果表明，具有反射光栅耦合结构的NbN探测器的最大电压响应率比具有F-P谐振器的NbN探测器大2倍。这表明反射光栅耦合结构可以有效地提高太赫兹探测器的探测效率。
