The dynamic process and microscopic mechanism of extraordinary terahertz transmission through perforated superconducting films.
Superconductor is a compelling plasmonic medium at terahertz frequencies owing to its intrinsic low Ohmic loss and good tuning property. However, the microscopic physics of the interaction between terahertz wave and superconducting plasmonic structures is still unknown. In this paper, we conducted experiments of the enhanced terahertz transmission through a series of superconducting NbN subwavelength hole arrays, and employed microscopic hybrid wave model in theoretical analysis of the role of hybrid waves in the enhanced transmission. The theoretical calculation provided a good match of experimental data. In particular, we obtained the following results. When the width of the holes is far below wavelength, the enhanced transmission is mainly caused by localized resonance around individual holes. On the contrary, when the holes are large, hybrid waves scattered by the array of holes dominate the extraordinary transmission. The surface plasmon polaritions are proved to be launched on the surface of superconducting film and the excitation efficiency increases when the temperature approaches critical temperature and the working frequency goes near energy gap frequency. This work will enrich our knowledge on the microscopic physics of extraordinary optical transmission at terahertz frequencies and contribute to developing terahertz plasmonic devices.
Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.|School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom.
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Wu
Key Lab of Optical Information Science and Technology (MOE), Institute of Modern Optics, Nankai University, Tianjin 300071, China.
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Zhang
Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
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Jin
Key Lab of Optical Information Science and Technology (MOE), Institute of Modern Optics, Nankai University, Tianjin 300071, China.
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Liu
Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
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Chen
Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
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Li
Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
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Zhang
Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
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Kang
Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
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Xu
Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
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Chen
Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.|National Institute for Materials Science, Tsukuba 305-0047, Japan.
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Wang
Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Tonouchi
Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
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Wu