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The dynamic process and microscopic mechanism of extraordinary terahertz transmission through perforated superconducting films.

Wu JB, Zhang X, Jin BB, Liu HT, Chen YH, Li ZY, Zhang CH, Kang L, Xu WW, Chen J, Wang HB, Tonouchi M, Wu PH - Sci Rep (2015)

Bottom Line: The theoretical calculation provided a good match of experimental data.In particular, we obtained the following results.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.

View Article: PubMed Central - PubMed

Affiliation: Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus

Comparison of the experimental data, HW model predictions, and RCWA computation data for the THz transmission spectra of W2.5.(a) The transmission spectra of W2.5 at different temperatures obtained from measurement (solid lines) and calculation using RCWA (dots). (b) The transmission spectra of W2.5 at 8.2 K obtained from the measurement, and calculation using RCWA, HW model and No-HW model. (c) The calculated absolute value of scattering coefficients of α and β at the NbN/air and NbN/MgO interfaces as a function of frequency at 8.2 K. (d) The simulated normalized electric field (E/E0) distribution at the interface of NbN/MgO at 8.2 K, where E is the calculated electric field excited around the hole and E0 denotes the average electric field of incident plane wave.
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f3: Comparison of the experimental data, HW model predictions, and RCWA computation data for the THz transmission spectra of W2.5.(a) The transmission spectra of W2.5 at different temperatures obtained from measurement (solid lines) and calculation using RCWA (dots). (b) The transmission spectra of W2.5 at 8.2 K obtained from the measurement, and calculation using RCWA, HW model and No-HW model. (c) The calculated absolute value of scattering coefficients of α and β at the NbN/air and NbN/MgO interfaces as a function of frequency at 8.2 K. (d) The simulated normalized electric field (E/E0) distribution at the interface of NbN/MgO at 8.2 K, where E is the calculated electric field excited around the hole and E0 denotes the average electric field of incident plane wave.

Mentions: The measured THz transmission frequency domain spectra of W2.5 at different temperatures are plotted in Fig. 3(a). The tuning behaviours of peak amplitude and resonance frequency are consistent with our previous work16. The hole area of W2.5 only takes 1.7% of the total area, and the transmission peak reaches as high as 86.2% at 8.2 K. Correspondingly, the normalized transmission coefficient, which is the ratio of energy transmitted through the sample to the energy incident on the holes at the transmission peak frequency, is 50.7, is much larger than that of perforated gold film (see Supplementary Note 1).


The dynamic process and microscopic mechanism of extraordinary terahertz transmission through perforated superconducting films.

Wu JB, Zhang X, Jin BB, Liu HT, Chen YH, Li ZY, Zhang CH, Kang L, Xu WW, Chen J, Wang HB, Tonouchi M, Wu PH - Sci Rep (2015)

Comparison of the experimental data, HW model predictions, and RCWA computation data for the THz transmission spectra of W2.5.(a) The transmission spectra of W2.5 at different temperatures obtained from measurement (solid lines) and calculation using RCWA (dots). (b) The transmission spectra of W2.5 at 8.2 K obtained from the measurement, and calculation using RCWA, HW model and No-HW model. (c) The calculated absolute value of scattering coefficients of α and β at the NbN/air and NbN/MgO interfaces as a function of frequency at 8.2 K. (d) The simulated normalized electric field (E/E0) distribution at the interface of NbN/MgO at 8.2 K, where E is the calculated electric field excited around the hole and E0 denotes the average electric field of incident plane wave.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4620484&req=5

f3: Comparison of the experimental data, HW model predictions, and RCWA computation data for the THz transmission spectra of W2.5.(a) The transmission spectra of W2.5 at different temperatures obtained from measurement (solid lines) and calculation using RCWA (dots). (b) The transmission spectra of W2.5 at 8.2 K obtained from the measurement, and calculation using RCWA, HW model and No-HW model. (c) The calculated absolute value of scattering coefficients of α and β at the NbN/air and NbN/MgO interfaces as a function of frequency at 8.2 K. (d) The simulated normalized electric field (E/E0) distribution at the interface of NbN/MgO at 8.2 K, where E is the calculated electric field excited around the hole and E0 denotes the average electric field of incident plane wave.
Mentions: The measured THz transmission frequency domain spectra of W2.5 at different temperatures are plotted in Fig. 3(a). The tuning behaviours of peak amplitude and resonance frequency are consistent with our previous work16. The hole area of W2.5 only takes 1.7% of the total area, and the transmission peak reaches as high as 86.2% at 8.2 K. Correspondingly, the normalized transmission coefficient, which is the ratio of energy transmitted through the sample to the energy incident on the holes at the transmission peak frequency, is 50.7, is much larger than that of perforated gold film (see Supplementary Note 1).

Bottom Line: The theoretical calculation provided a good match of experimental data.In particular, we obtained the following results.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.

View Article: PubMed Central - PubMed

Affiliation: Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus