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By:Tie Jun Cui and Xiaopeng Shen, State Key Laboratory of Millimeter Waves,
Southeast University, Nanjing 210096, China. Email: tjcui@seu.edu.cn
Forum for Electromagnetic Research Methods and Application Technologies (FERMAT)
Spoof Surface Plasmons and Applications in Microwave Frequencies
Keyword: Surface plasmon polaritons (SPPs), conformal surface plasmons, localized surface plasmons, SPP waveguide, passive SPP components, active SPP components.
Abstract:We present several spoof surface plasmon structures in the microwave and terahertz frequencies, including surface plasmon polariton (SPP) waveguides and the relevant devices, and localized surface plasmons (LSPs). In details, we will introduce our recent work on ultrathin and flexible SPP waveguides with subwavelength width, which can sustain highly localized SPPs along two orthogonal directions in broadband by keeping good modal shapes and propagating long distance with low bending loss, and the resulting compact plasmonic filters, bends, beam spillters, polarizers, and resonantors. We also demonstrate spoof LSPs on planar ultrathin textured metallic disks with subwavelength scales, which have potential applications as plasmonic sensors in the microwave and terahertz frequencies.
References 1. X. Shen, T. J. Cui, D. Martin-Canob, and F. J. Garcia-Vidal, “Conformal
surface plasmons propagating on ultrathin and flexible films,” Proceedings of the National Academy of Science, PNAS, vol. 110, no. 1, pp. 40-45 (2013)
2. X. Shen and T. J. Cui, “Planar plasmonic metamaterial on a thin film with nearly zero thickness,” Applied Physics Letters, vol. 102, 211909 (2013)
3. X. Gao, J. H. Shi, X. Shen, H. F. Ma, W. X. Jiang, L. Li, and T. J. Cui, “Ultrathin dual-band SPP waveguide and frequency splitter in microwave frequencies,” Applied Physics Letters, vol. 102, 151912 (2013)
4. H. F. Ma, X. Shen, Q. Cheng, W. X. Jiang, and T. J. Cui, “Broadband and high-efficiency conversion from guided waves to spoof surface plasmon polaritons,” Laser and Photonics Review, vol. 8, no. 1, pp. 146-151 (2014)
5. X. Gao, L. Zhou, Z. Liao, H. F. Ma, and T. J. Cui, “An ultra-wideband surface plasmonic filter in microwave frequencies,” Applied Physics Letters, vol. 104, 191603 (2014)
6. B. C. Pan, Z. Liao, J. Zhao, and T. J. Cui, “Controlling rejections of spoof surface plasmon polaritons using metamaterial particles,” Optics Express, vol. 22, pp. 13940-13950 (2014)
References
7. H. C. Zhang, S. Liu, X. Shen, L. H. Chen, L. Li, and T. J. Cui, “Broadband amplification of spoof surface plasmon polaritons in the microwave frequency,” Laser and Photonics Review, DOI 10.1002/lpor.201400131, (2014)
8. X. Shen and T. J. Cui, “Ultrathin plasmonic metamaterial for spoof localized surface plasmons,” Laser and Photonics Review, vol. 8, no. 1, pp. 137-145 (2014)
9. P. A. Huidobro, X. Shen, J. Cuerda, E. Moreno, L. Martin-Moreno, F. J. Garcia-Vidal, T. J. Cui, and J. B. Pendry, “Magnetic localized surface plasmons,” Physical Review X, vol. 4, 021003 (2014).
10. J. J. Xu, H. C. Zhang, Q. Zhang, and T. J. Cui, “Efficient conversion of surface-plasmon-like modes to spatial radiated modes,” Applied Physics Letters, vol. 105, accepted for publication, 2015.
◆ Prof. Francisco J. Garcia-Vidal
Universidad Autonoma de Madrid, Spain
◆ Sir John Pendry
Imperial College London, UK
Collaboration Acknowledgments
Outline
◆ Background and Motivations
◆ Conformal Spoof SPPs and Devices
◆ Conversion from SPPs to Guided Waves
◆ Spoof Localized SPs
◆ Conclusions
Spoof (or Mimicking, Designer) SPPs
Natural SPPs only exist at optical frequencies.
To realize SPPs at lower frequencies (GHz, THz), spoof SPPs have been proposed.
The concept of “designer” surface modes opens opportunities to control and direct the radiations at surfaces within a subwavelength region.
Pendry et al. , Science 305, 847 (2004). Garcia-Vidal et al., J. Opt. A: Pure Appl. Opt. 7, S94 (2005).
A theoretical study on localized surface plasmons (LSPs)
Spoof LSPs
F. J. Garcia-Vidal, PRL 108, 223905, 2012
The Motivation of Our Study The existing spoof SP structures are all 3D
(corrugated structures on metal surface, drilling holes on metal surface, Domino structures).
They are inconvenient for integration.
Our motivations: To propose, design, and realize spoof SPPs and
LSPs on ultrathin metal surfaces; To construct planar and conformal SPP waveguides,
SPP devices, and SPP circuits; To propose and construct ultrathin planar LSPs.
Spoof SPPs on Different-Thickness Structured Metal Strip
Shen, et al., PNAS 110, 40-45 (2013)
The proposed ultrathin SPP structure works from microwave to THz frequencies
Spoof SPPs on Ultrathin Metal Film
Experiment results: Wideband (7GHz – 11 GHz)
Excellent propagation properties with low loss and long propagation distance.
Low loss
Good modal
shape
Long distance
Exponential
decay in both
orthogonal
directions
Spoof SPPs Devices
Beam Bending Beam Splitter
(Wideband)
Ring Resonator
Shen and Cui, APL 102, 211909, 2013
Spoof SPPs Devices Gao et al., APL 102, 151912, 2013
Dual-Band SPP Frequency Splitter
Flexible and Conformal SPPs
Flexible Copper Clad Laminate (FCCL)
Shen, et al., PNAS 110, 40-45 (2013)
Flexible and Conformal SPPs
Efficient Polarization Conversion
Sharp Bending
Flexible and Conformal SPPs
Shen, et al., PNAS 110, 40-45 (2013)
Conversion of Guided Modes and SPPs Ma et al., Laser & Photonics Review,
vol. 8, pp. 146-151 (2014)
Conversion of Guided Modes to SPPs
• Very high efficiency • Very broad band • Direct measurements of
reflection & transmission
Advantage: Very Small Cross Talk
SPP Filters Gao et al., APL 104, 191603 (2014)
SPP Filters Pan et al., Opt. Exp. 22, 13940 (2014)
SPP Filters
Spoof Integrated SPP Circuits Shen, Zhang & Cui, unpublished, 2014
• Five-Port Circuit: • Splitter • Ring Resonator • Directional Coupler
Radiation of SPP Waves Xu et al., Efficient conversion of surface-plasmon-like modes to spatial radiated modes, APL, accepted for publication, 2015
A Spoof SPP Emitter, in which the gradient index metasurface will change the SPP modes to radiated modes
Radiation of SPP Waves
Different gradience of the metasurface will result in different radiation performance.
Radiation of SPP Waves
The simulated and measured reflection coefficients, showing good radiation efficiency in wide frequency band.
The measured near-field distributions (phases) and far-field radiation patterns of the proposed spoof SPP emitters, in which the beam deflection angles are -22.5o, -2o, and 16.1o
Amplification of SPP Waves
Amplifier Chip SPP Waveguide
Zhang et al., Laser and Photonics Review, DOI 10.1002/lpor.201400131, (2014)
Amplification of SPP Waves
Measured Near Fields for SPP Amplification
• Hybrid SPP-
Conventional
Integrated Circuits
• Hybrid Passive
and Active SPP
Integrated Circuits
SPP Mixers
Zhang, Liu & Cui, unpublished, 2014
Spoof Localized SPs Shen and Cui, Laser and Photonics Review, vol. 8, pp. 137-145 (2014)
Spoof Localized SPs Monopole Excitation: Simulation Results
quadrupole
dipole
hexapole octopole
decapole dodeca-pole quattuordec-pole
Spoof Localized SPs Monopole Excitation: Measured Results
quadrupole
dipole
hexapole octopole
decapole dodeca-pole quattuordec-pole
Spoof Localized SPs
Shen and Cui, Laser and Photonics Review, vol. 8, pp. 137-145 (2014)
Subwavelength Spoof LSPs
Huidobro, Shen et al., Physical Review X 4, 021003 (2014)
0.5 1.0 1.5 2.0 2.50
1000
2000
3000
4000
ECS RCS ACS
ECS/
RCS/
ACS
Frequency (GHz)
r w
g
x, K
y, E
. H
ED
MD
The spirally curved grooves make the ultrathin LSP structure more compact: with subwavelength scale. The right figure shows the electric and magnetic dipole resonances.
Electric Dipole Magnetic Dipole
Power Flux
Far-Field Patterns
Near Fields
Subwavelength Spoof LSPs
Measurement Results
Summary
With the ultrathin planar or flexible structures, SPs will be practical in the microwave and terahertz frequencies.
We produced compact-size SPP waveguides and various passive devices.
We proposed the first SPP amplifier in the microwave frequencies, which is the basis to realize SPP circuits and systems.
We also produced subwavelength LSP sensors.
Thank you!
tjcui@seu.edu.cn
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