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. 2014 Aug 25;9(1):430.
doi: 10.1186/1556-276X-9-430. eCollection 2014.

Spectral and Mode Properties of Surface Plasmon Polariton Waveguides Studied by Near-Field Excitation and Leakage-Mode Radiation Measurement

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Free PMC article

Spectral and Mode Properties of Surface Plasmon Polariton Waveguides Studied by Near-Field Excitation and Leakage-Mode Radiation Measurement

Ming-Yang Pan et al. Nanoscale Res Lett. .
Free PMC article

Abstract

We present a method to couple surface plasmon polariton (SPP) guiding mode into dielectric-loaded SPP waveguide (DLSPPW) devices with spectral and mode selectivity. The method combined a transmission-mode near-field spectroscopy to excite the SPP mode and a leakage radiation optical microscope for direct visualization. By using a near-field fiber tip, incident photons with different wavelengths were converted into SPPs at the metal/dielectric interface. Real-time SPP radiation images were taken through leakage radiation images. The wavelength-dependent propagation lengths for silver- and gold-based DLSPPWs were measured and compared. It confirms that silver-based SPP has a propagation length longer than a gold-based one by 1.25, 1.38, and 1.52 times for red, green, and blue photons. The resonant coupling as a function of wavelength in dual DLSPPWs was measured. The coupling lengths measured from leakage radiation images were in good agreement with finite-difference time domain simulations. In addition, the propagation profile due to multi-SPP modes interference was studied by changing position of the fiber tip. In a multimode DLSPPW, SPP was split into two branches with a gap of 2.237 μm when the tip was at the center of the waveguide. It became a zigzag profile when the SPP was excited at the corner of the waveguide.

Keywords: Coupling method; Nanophotonics; Near-field optics; Optical waveguide; Surface plasmon polariton.

Figures

Figure 1
Figure 1
Schematic setup of a DLSPPW excited by the NFES. The excitation light was a supercontinuum light and the incident wavelength was selected by a monochromator. The DLSPPW was made of a dielectric strip coated on a metallic thin film on a glass substrate.
Figure 2
Figure 2
Leakage radiation images and intensity profiles of DLSPPW for gold-based and silver-based DLSPPWs. Leakage radiation images of SPPs on (a) gold film and (b) silver film. The bright spot is the excitation source from the fiber tip. (c) The SPP intensities as a function of distance as measured at RGB pixels in a color CCD.
Figure 3
Figure 3
A multimode waveguide excited by NFES. (a) Leakage radiation image when the fiber tip was at the center of the waveguide. The red arrow shows the location of intensity was spitted into 50:50. (b, c) Leakage radiation images when the fiber tip was located at two different corners of the waveguide. (d to f) The calculated optical field distributions (Ez) for near-field excitation at different positions, (d) at the center of waveguide, (e, f) and at two different corners.
Figure 4
Figure 4
Dual DLSPPW coupler studied by NFES with different wavelengths. (a) SEM image of DLSPPW-based dual waveguides coupler. (b) Leakage radiation images of SPP waves propagation in the coupler from λ = 700 to 800 nm wavelengths. Cyan dash line showed the coupling length was decreased with the incident wavelength. (c) The measured and calculated coupling lengths as a function of wavelength. Red line shows the calculation results. Black line shows the measured results.

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References

    1. Steinberger B, Hohenau A, Ditlbacher H, Stepanov AL, Drezet A, Aussenegg FR, Leitner A, Krenn JR. Dielectric stripes on gold as surface plasmon waveguides. Appl Phys Lett. 2006;9:094104. doi: 10.1063/1.2180448. - DOI
    1. Oulton RF, Sorger VJ, Genov DA, Pile DFP, Zhang X. A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation. Nat Photonics. 2008;9:496–500. doi: 10.1038/nphoton.2008.131. - DOI
    1. Bozhevolnyi S, Volkov V, Devaux E, Ebbesen T. Channel plasmon-polariton guiding by subwavelength metal grooves. Phys Rev Lett. 2005;9:046802. - PubMed
    1. Bozhevolnyi SI, Volkov VS, Devaux E, Laluet JY, Ebbesen TW. Channel plasmon subwavelength waveguide components including interferometers and ring resonators. Nature. 2006;9:508–511. doi: 10.1038/nature04594. - DOI - PubMed
    1. Dicken MJ, Sweatlock LA, Pacifici D, Lezec HJ, Bhattacharya K, Atwater HA. Electrooptic modulation in thin film barium titanate plasmonic interferometers. Nano letters. 2008;9:4048–4052. doi: 10.1021/nl802981q. - DOI - PubMed

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