OSA's Digital Library

Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 21, Iss. 3 — Feb. 11, 2013
  • pp: 2748–2756
« Show journal navigation

Tunable directive radiation of surface-plasmon diffraction gratings

Youngkyu Lee, Kazunori Hoshino, Andrea Alù, and Xiaojing Zhang  »View Author Affiliations


Optics Express, Vol. 21, Issue 3, pp. 2748-2756 (2013)
http://dx.doi.org/10.1364/OE.21.002748


View Full Text Article

Acrobat PDF (1489 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

We experimentally demonstrate tunable radiation from a periodic array of plasmonic nanoscatterers, tailored to convert surface plasmon polaritons into directive leaky modes. Extending our previous studies on efficient directional beaming based on leaky-wave radiation from periodic gratings driven by a subwavelength slit, we experimentally show dynamic beam sweeping by tuning the directional leaky-wave mechanism in real-time. Two alternative tuning mechanisms, wavelength- and index-mediated beam sweeping, are employed to modify the relative phase of scattered light at each grating edge and provide the required modification of the radiation angle.

© 2013 OSA

1. Introduction

Tailoring the electromagnetic radiation of an array of antennas is a classic subject of interest in many research areas since its first explorations in 1905 by Karl Ferdinand Braun. At microwaves and radio frequencies, phased arrays are commonly used to scan a directive radiation pattern in the angular spectrum. By manipulating the relative phase of the signal feeding each antenna element, radiation can be pointed towards the desired direction and suppressed in all others. One useful feature provided by phased arrays is dynamic beam sweeping: by actively modifying the phase with which each element is driven, it is possible to tailor the overall radiation towards an arbitrary direction and suppress undesired radiation in other directions. A similar approach may be applied in plasmonic nano-optics, where an array of small scatterers [1

1. J. Li, A. Salandrino, and N. Engheta, “Shaping light beams in nanometer scale: A Yagi-Uda nanoantenna in the optical domain,” Phys. Rev. B 76(24), 245403 (2007). [CrossRef]

9

9. X. X. Liu and A. Alù, “Subwavelength leaky-wave optical nanoantennas: Directive radiation from linear array of plasmonic nanoparticles,” Phys. Rev. B 82(14), 144305 (2010). [CrossRef]

] may be used to realize directive optical radiation. By modifying the phase of the excitation of each radiator, the collective optical radiation may be directed and dynamically manipulated towards the direction of interest. Recently, Yagi-Uda nanoantennas [1

1. J. Li, A. Salandrino, and N. Engheta, “Shaping light beams in nanometer scale: A Yagi-Uda nanoantenna in the optical domain,” Phys. Rev. B 76(24), 245403 (2007). [CrossRef]

5

5. T. H. Taminiau, F. D. Stefani, and N. F. van Hulst, “Enhanced directional excitation and emission of single emitters by a nano-optical Yagi-Uda antenna,” Opt. Express 16(14), 10858–6 (2008). [CrossRef] [PubMed]

,8

8. T. Coenen, E. J. R. Vesseur, A. Polman, and A. F. Koenderink, “Directional emission from plasmonic Yagi-Uda antennas probed by angle-resolved cathodoluminescence spectroscopy,” Nano Lett. 11(9), 3779–3784 (2011). [CrossRef] [PubMed]

] consisting of parasitically phased elements driven by a confined quantum source have been demonstrated at optical frequencies, providing directional emission from the nanoscale to the far-field. Similarly, slit-based patterned planar surfaces have been reported showing directive optical radiation [10

10. T. W. Ebbesen, H. J. Lezec, H. F. Ghaemi, T. Thio, and P. A. Wolff, “Extraordinary optical transmission through sub-wavelength hole arrays,” Nature 391(6668), 667–669 (1998). [CrossRef]

17

17. H. Kim and B. Lee, “Unidirectional surface plasmon polariton excitation on single slit with oblique backside illumination,” Plasmonics 4(2), 153–159 (2009). [CrossRef]

]. Albeit various design efforts have been spent to develop directive and controlled radiation for relevant applications in nano-optics, limited experimental efforts showing the possibility of dynamic beam sweeping have been reported [11

11. H. J. Lezec, A. Degiron, E. Devaux, R. A. Linke, L. Martin-Moreno, F. J. Garcia-Vidal, and T. W. Ebbesen, “Beaming light from a subwavelength aperture,” Science 297(5582), 820–822 (2002). [CrossRef] [PubMed]

].

In this paper, we focus on a nanopatterned metallic surface over which tunable directional optical radiation is realized using a subwavelength slit coupled on one side to an array of periodic gratings. The directive radiation is based on the leaky-wave mode supported by the periodic structure in a given frequency band of interest. In the proposed configuration, the subwavelength slit excites the array over a plasmonic screen, launching surface plasmon polaritons (SPPs) that are converted into leaky modes by the proper periodic corrugations. The coupling between the excitation and the SPP mode is maximized by controlling the slit width through nanofabrication and the angle of excitation, so that SPPs are generated primarily on the grating side [17

17. H. Kim and B. Lee, “Unidirectional surface plasmon polariton excitation on single slit with oblique backside illumination,” Plasmonics 4(2), 153–159 (2009). [CrossRef]

19

19. Y. Lee, A. Alù, and J. X. Zhang, “Efficient apertureless scanning probes using patterned plasmonic surfaces,” Opt. Express 19(27), 25990–25999 (2011). [CrossRef] [PubMed]

] to maximize the coupling efficiency with the leaky-wave mode [18

18. Y. Lee, K. Hoshino, A. Alù, and X. J. Zhang, “Efficient directional beaming from small apertures using surface-plasmon diffraction gratings,” Appl. Phys. Lett. 101(4), 041102 (2012). [CrossRef]

]. This solution has also the advantage of suppressing the conventional slit diffraction and unwanted side lobes for a specifically optimized oblique angle of illumination. Similar to radio-frequency leaky-wave antennas [20

20. A. A. Oliner and D. R. Jackson, Antenna Engineering Handbook, 4th ed. (McGraw-Hill, New York, 2007).

,21

21. C. A. Balanis, Antenna Theory Analysis and Design, 3rd ed. (John Wiley & Sons, 2005).

], it is then possible to sweep the direction of optical radiation by manipulating the effective electrical distance between the scatterers.

2. Design of tunable optical phased array

The proposed optical phased array consists of an array of periodic metal bumps driven by a slit aperture, which couples incident transverse-magnetic (TM) light into plasmonic modes. In this configuration, shown in Fig. 1
Fig. 1 Schematic of a tunable directional optical antenna: a subwavelength slit with a left-side array of periodic gratings, consisting of corrugations in a plasmonic screen. Note that εD,εM,andεSUBindicate the relative permittivity of surrounding medium, metal, and supporting substrate (BK7), respectively. Directive radiation at a specific angleθcan be achieved by a proper choice of surrounding mediumεDand wavelengthλof operation; and its directivity can be further enhanced by optimizing illumination angleϕ.
, a one-dimensional (1D) array of periodic metal bumps serves as a directive optical antenna, effectively converting the dominant SPP mode into a leaky-wave mode radiating in free space. Previously we have studied efficient directive radiation from metal bumps excited by SPPs [18

18. Y. Lee, K. Hoshino, A. Alù, and X. J. Zhang, “Efficient directional beaming from small apertures using surface-plasmon diffraction gratings,” Appl. Phys. Lett. 101(4), 041102 (2012). [CrossRef]

].

In our model, we have shown that the phase matching condition to form a collimated directive leaky-mode within the first diffraction order of each scatterer is given by
p(Re[kSP]+kDsinθ)=2π,
(1)
where, the SPP wavenumber is kSP=2π[(εMεD)/(εM+εD)]1/2/λ, which is perturbed into a directive leaky-wave mode with wavenumber kD=2πεD/λ by the periodic corrugations, εD is the dielectric permittivity of background, εM is the metal permittivity, θ is the angle of radiation, and p is the array periodicity. We assume that the permittivity of all involved materials is dispersive hence a function of the operating wavelength λ. Since the effective electrical lengthpRe[kSP]andpkDsinθ,governing the matching condition Eq. (1), are controllable by the operating wavelength and background permittivity, we may tune the direction of optical radiation by tuning either one of these quantities. Following the design methodology [18

18. Y. Lee, K. Hoshino, A. Alù, and X. J. Zhang, “Efficient directional beaming from small apertures using surface-plasmon diffraction gratings,” Appl. Phys. Lett. 101(4), 041102 (2012). [CrossRef]

], we choose initial design parameters to realize maximum radiation at θ=25° for operating wavelength λ=630 nm and free space (εD = 1). It is important to note that the proposed configuration can tailor light into any propagating mode of interest. Even though we focus on coupling energy to free-space with leaky modes, light may also be coupled to surface plasmon modes by properly choosing the design parameters [22

22. F. López-Tejeira, S. G. Rodrigo, L. Martín-Moreno, F. J. García-Vidal, E. Devaux, T. W. Ebbesen, J. R. Krenn, I. P. Radko, S. I. Bozhevolnyi, M. U. González, J. C. Weeber, and A. Dereux, “Efficient unidirectional nanoslit couplers for surface plasmons,” Nat. Phys. 3(5), 324–328 (2007). [CrossRef]

].

For the excitation of such optical phased array consisting of periodic metal bumps, a perforated slit in plasmonic screen is chosen to serve as a driving element, providing efficient conversion of incident TM light into surface plasmon modes [17

17. H. Kim and B. Lee, “Unidirectional surface plasmon polariton excitation on single slit with oblique backside illumination,” Plasmonics 4(2), 153–159 (2009). [CrossRef]

19

19. Y. Lee, A. Alù, and J. X. Zhang, “Efficient apertureless scanning probes using patterned plasmonic surfaces,” Opt. Express 19(27), 25990–25999 (2011). [CrossRef] [PubMed]

]. With tilted illumination, a perforated slit that supports higher-order guided modes can provide unidirectional generation of SPP at its exit, maximizing the radiation efficiency of this system. The mode supported by a plasmonic slit follows the dispersion equation
i[w(β2+kD2)1/2mπ]=2tanh1[iεD(β2εMkD2)1/2/εM(β2+kD2)1/2].
(2)
A slit width w=300 nm is therefore chosen to support the higher-order (m=1) guided mode, which may couple energy into the desired SPP only on the side of the grating for a specific excitation angle.

3. Device fabrication and experimental characterization

The radiation patterns from the fabricated device were then characterized with a custom optical setup allowing us to control the angle of both illumination and radiation. The angular intensity profile was recorded on a CCD, as shown in Fig. 2
Fig. 2 Schematic of the optical setup to measure far-field radiation patterns. Embedded pictures: a scanning electron micrograph (SEM) of the fabricated device (top) and microscope image of PDMS spacer (bottom).
. A 300 nm slit was excited with oblique backside illumination of a collimated TM plane-wave at a specific wavelength of operation. A broadband white light emitting diode (LED) was used with a bandpass filter to acquire the desired spectra at the output. Angular-dependent optical signals from the device were collected with low numerical aperture (NA) optics (Olympus LMPlan X20/0.4 with closed iris) and captured by a charge-coupled device (CCD). The fabricated device and illumination optics were mounted on separate three-axis alignment systems with rotational stage, allowing for the control of both illumination and measurement angles. Detailed intensity profiling for angular dependent radiation are provided in Fig. 3
Fig. 3 Radiation pattern profiles from CCD images captured at various angles for λ=630 nm and no index matching fluid in the spacer.
.

4. Experimental results and discussion

In Fig. 4(a), radiation patterns were recorded after varying the index range of matching fluidsnD=εD1/2=1.26 ~1.62 at the fixed wavelength λ=630 nm. We note that the weak frequency dispersion of each index matching fluid is not significant within the spectral bandwidth considered in each measurement, as it is contained within an index variation of less than 0.001. In illuminating the slit, we used TM polarized light at the operating wavelength with 10 nm of spectral FWHM bandwidth. In Fig. 4(b), conversely, we show beam scanning changing the wavelength of illumination (λ=500 ~650 nm), in the absence of index matching fluids (nD=1). Also here, the spectral FWHM for each illumination was 10 nm. To compare the angular shift and the angular confinement of radiation pattern (angular FWHM) for both tuning mechanisms, each recorded pattern in Fig. 4 is normalized with respect to its peak radiation intensity.

As seen in Fig. 4, we have experimentally demonstrated the two tuning mechanisms scanning directive radiation. By varying the background refractive index (nD=1.00~1.62), we achieve a shift of peak radiation angle of about 39.7°; and by varying the wavelength of operationλfrom 500 nm to 650 nm, the peak radiation angleθchanges from −1° to + 27°. Detailed angular sensitivity of directive radiation with respect to these tuning mechanisms is summarized in Fig. 5
Fig. 5 Peak radiation angle as a function of wavelength (black) and the refractive index of surrounding medium (red). Each dashed line is a fitting curve for varying peak radiation angle.
. As expected, nearly linear variation with the angle of radiation is found, both in terms of wavelength of operation and of change in the refractive index. The angle may scan from positive values to broadside radiation, with interesting implications for beam scanning, optical communications and plasmonic sensors at the molecular scale.

As discussed above, it is important to note that the proposed geometry offers comparable sensitivity to conventional SPR based devices. For instance, the proposed configuration shows an angular sensitivity satisfying the relation δθDRδελ0/2p upon the presence of small dielectric perturbations in the surrounding medium (εD=1+δε) if |Re(εM)|>>1 and |δε|<<1 are assumed. Such sensitivity is comparable to that of conventional Kretschmann configuration [28

28. E. Kretschmann and H. Raether, “Radiative decay of non-radiative surface plasmons excited by light,” Z. Naturforsch. A 23, 2135–2136 (1968).

], so we may find potential sensing applications based on dielectric perturbations.

5. Conclusion

Acknowledgment

This research was performed in the Department of Biomedical Engineering, Microelectronics Research Center (MRC), and Center for Nano and Molecular Science (CNM) at the University of Texas at Austin. We gratefully acknowledge the financial support from NSF CAREER Award Grants (No. 0953311, PI: Alù, and No. 0846313, PI: Zhang) and the DARPA Young Faculty Award (N66001-10-1-4049, PI: Zhang).

References and links

1.

J. Li, A. Salandrino, and N. Engheta, “Shaping light beams in nanometer scale: A Yagi-Uda nanoantenna in the optical domain,” Phys. Rev. B 76(24), 245403 (2007). [CrossRef]

2.

T. Kosako, Y. Kadoya, and H. F. Hofmann, “Directional control of light by a nano-optical Yagi–Uda antenna,” Nat. Photonics 4(5), 312–315 (2010). [CrossRef]

3.

A. G. Curto, G. Volpe, T. H. Taminiau, M. P. Kreuzer, R. Quidant, and N. F. van Hulst, “Unidirectional emission of a quantum dot coupled to a nanoantenna,” Science 329(5994), 930–933 (2010). [CrossRef] [PubMed]

4.

H. F. Hofmann, T. Kosako, and Y. Kadoya, “Design parameters for a nano-optical Yagi–Uda antenna,” New J. Phys. 9(7), 217 (2007). [CrossRef]

5.

T. H. Taminiau, F. D. Stefani, and N. F. van Hulst, “Enhanced directional excitation and emission of single emitters by a nano-optical Yagi-Uda antenna,” Opt. Express 16(14), 10858–6 (2008). [CrossRef] [PubMed]

6.

G. Pellegrini, G. Mattei, and P. Mazzoldi, “Tunable, directional and wavelength selective plasmonic nanoantenna arrays,” Nanotechnology 20(6), 065201 (2009). [CrossRef] [PubMed]

7.

A. F. Koenderink, “Plasmon nanoparticle array waveguides for single photon and single plasmon sources,” Nano Lett. 9(12), 4228–4233 (2009). [CrossRef] [PubMed]

8.

T. Coenen, E. J. R. Vesseur, A. Polman, and A. F. Koenderink, “Directional emission from plasmonic Yagi-Uda antennas probed by angle-resolved cathodoluminescence spectroscopy,” Nano Lett. 11(9), 3779–3784 (2011). [CrossRef] [PubMed]

9.

X. X. Liu and A. Alù, “Subwavelength leaky-wave optical nanoantennas: Directive radiation from linear array of plasmonic nanoparticles,” Phys. Rev. B 82(14), 144305 (2010). [CrossRef]

10.

T. W. Ebbesen, H. J. Lezec, H. F. Ghaemi, T. Thio, and P. A. Wolff, “Extraordinary optical transmission through sub-wavelength hole arrays,” Nature 391(6668), 667–669 (1998). [CrossRef]

11.

H. J. Lezec, A. Degiron, E. Devaux, R. A. Linke, L. Martin-Moreno, F. J. Garcia-Vidal, and T. W. Ebbesen, “Beaming light from a subwavelength aperture,” Science 297(5582), 820–822 (2002). [CrossRef] [PubMed]

12.

S. Kim, H. Kim, Y. Lim, and B. Lee, “Off-axis directional beaming of optical field diffracted by a single subwavelength metal slit with asymmetric dielectric surface gratings,” Appl. Phys. Lett. 90(5), 051113 (2007). [CrossRef]

13.

H. Kim, J. Park, and B. Lee, “Tunable directional beaming from subwavelength metal slits with metal-dielectric composite surface gratings,” Opt. Lett. 34(17), 2569–2571 (2009). [CrossRef] [PubMed]

14.

F. Hao, R. Wang, and J. Wang, “A design methodology for directional beaming control by metal slit–grooves structure,” J. Opt. 13(1), 015002 (2011). [CrossRef]

15.

S. Kim, Y. Lim, H. Kim, J. Park, and B. Lee, “Optical beam focusing by a single subwavelength metal slit surrounded by chirped dielectric surface gratings,” Appl. Phys. Lett. 92(1), 013103 (2008). [CrossRef]

16.

P. Chen, Q. Gan, F. J. Bartoli, and L. Zhu, “Near-field-resonance-enhanced plasmonic light beaming,” IEEE Photon. J. 2(1), 8–17 (2010). [CrossRef]

17.

H. Kim and B. Lee, “Unidirectional surface plasmon polariton excitation on single slit with oblique backside illumination,” Plasmonics 4(2), 153–159 (2009). [CrossRef]

18.

Y. Lee, K. Hoshino, A. Alù, and X. J. Zhang, “Efficient directional beaming from small apertures using surface-plasmon diffraction gratings,” Appl. Phys. Lett. 101(4), 041102 (2012). [CrossRef]

19.

Y. Lee, A. Alù, and J. X. Zhang, “Efficient apertureless scanning probes using patterned plasmonic surfaces,” Opt. Express 19(27), 25990–25999 (2011). [CrossRef] [PubMed]

20.

A. A. Oliner and D. R. Jackson, Antenna Engineering Handbook, 4th ed. (McGraw-Hill, New York, 2007).

21.

C. A. Balanis, Antenna Theory Analysis and Design, 3rd ed. (John Wiley & Sons, 2005).

22.

F. López-Tejeira, S. G. Rodrigo, L. Martín-Moreno, F. J. García-Vidal, E. Devaux, T. W. Ebbesen, J. R. Krenn, I. P. Radko, S. I. Bozhevolnyi, M. U. González, J. C. Weeber, and A. Dereux, “Efficient unidirectional nanoslit couplers for surface plasmons,” Nat. Phys. 3(5), 324–328 (2007). [CrossRef]

23.

L. VJ, N. P. Kobayashi, M. S. Islam, W. Wu, P. Chaturvedi, N. X. Fang, S. Y. Wang, and R. S. Williams, “Ultrasmooth silver film deposited with a germanium nucleation layer,” Nano Lett. 9, 178–182 (2009).

24.

J. Y. Laluet, A. Drezet, C. Genet, and T. W. Ebbesen, “Generation of surface plasmons at single subwavelength slits: from slit to ridge plasmon,” New J. Phys. 10(10), 105014 (2008). [CrossRef]

25.

P. Lalanne, J. P. Hugonin, and J. C. Rodier, “Theory of Surface Plasmon Generation at Nanoslit Apertures,” Phys. Rev. Lett. 95(26), 263902 (2005). [CrossRef] [PubMed]

26.

P. Lalanne and J. P. Hugonin, “Interaction between optical nano-objects at metallo-dielectric interfaces,” Nat. Phys. 2(8), 551–556 (2006). [CrossRef]

27.

Q. Gan, Y. Gao, Q. Wang, L. Zhu, and F. Bartoli, “Surface plasmon waves generated by nanogrooves through spectral interference,” Phys. Rev. B 81(8), 085443 (2010). [CrossRef]

28.

E. Kretschmann and H. Raether, “Radiative decay of non-radiative surface plasmons excited by light,” Z. Naturforsch. A 23, 2135–2136 (1968).

OCIS Codes
(050.1220) Diffraction and gratings : Apertures
(240.6680) Optics at surfaces : Surface plasmons

ToC Category:
Optics at Surfaces

History
Original Manuscript: October 9, 2012
Revised Manuscript: November 16, 2012
Manuscript Accepted: November 19, 2012
Published: January 29, 2013

Citation
Youngkyu Lee, Kazunori Hoshino, Andrea Alù, and Xiaojing Zhang, "Tunable directive radiation of surface-plasmon diffraction gratings," Opt. Express 21, 2748-2756 (2013)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-21-3-2748


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. J. Li, A. Salandrino, and N. Engheta, “Shaping light beams in nanometer scale: A Yagi-Uda nanoantenna in the optical domain,” Phys. Rev. B76(24), 245403 (2007). [CrossRef]
  2. T. Kosako, Y. Kadoya, and H. F. Hofmann, “Directional control of light by a nano-optical Yagi–Uda antenna,” Nat. Photonics4(5), 312–315 (2010). [CrossRef]
  3. A. G. Curto, G. Volpe, T. H. Taminiau, M. P. Kreuzer, R. Quidant, and N. F. van Hulst, “Unidirectional emission of a quantum dot coupled to a nanoantenna,” Science329(5994), 930–933 (2010). [CrossRef] [PubMed]
  4. H. F. Hofmann, T. Kosako, and Y. Kadoya, “Design parameters for a nano-optical Yagi–Uda antenna,” New J. Phys.9(7), 217 (2007). [CrossRef]
  5. T. H. Taminiau, F. D. Stefani, and N. F. van Hulst, “Enhanced directional excitation and emission of single emitters by a nano-optical Yagi-Uda antenna,” Opt. Express16(14), 10858–6 (2008). [CrossRef] [PubMed]
  6. G. Pellegrini, G. Mattei, and P. Mazzoldi, “Tunable, directional and wavelength selective plasmonic nanoantenna arrays,” Nanotechnology20(6), 065201 (2009). [CrossRef] [PubMed]
  7. A. F. Koenderink, “Plasmon nanoparticle array waveguides for single photon and single plasmon sources,” Nano Lett.9(12), 4228–4233 (2009). [CrossRef] [PubMed]
  8. T. Coenen, E. J. R. Vesseur, A. Polman, and A. F. Koenderink, “Directional emission from plasmonic Yagi-Uda antennas probed by angle-resolved cathodoluminescence spectroscopy,” Nano Lett.11(9), 3779–3784 (2011). [CrossRef] [PubMed]
  9. X. X. Liu and A. Alù, “Subwavelength leaky-wave optical nanoantennas: Directive radiation from linear array of plasmonic nanoparticles,” Phys. Rev. B82(14), 144305 (2010). [CrossRef]
  10. T. W. Ebbesen, H. J. Lezec, H. F. Ghaemi, T. Thio, and P. A. Wolff, “Extraordinary optical transmission through sub-wavelength hole arrays,” Nature391(6668), 667–669 (1998). [CrossRef]
  11. H. J. Lezec, A. Degiron, E. Devaux, R. A. Linke, L. Martin-Moreno, F. J. Garcia-Vidal, and T. W. Ebbesen, “Beaming light from a subwavelength aperture,” Science297(5582), 820–822 (2002). [CrossRef] [PubMed]
  12. S. Kim, H. Kim, Y. Lim, and B. Lee, “Off-axis directional beaming of optical field diffracted by a single subwavelength metal slit with asymmetric dielectric surface gratings,” Appl. Phys. Lett.90(5), 051113 (2007). [CrossRef]
  13. H. Kim, J. Park, and B. Lee, “Tunable directional beaming from subwavelength metal slits with metal-dielectric composite surface gratings,” Opt. Lett.34(17), 2569–2571 (2009). [CrossRef] [PubMed]
  14. F. Hao, R. Wang, and J. Wang, “A design methodology for directional beaming control by metal slit–grooves structure,” J. Opt.13(1), 015002 (2011). [CrossRef]
  15. S. Kim, Y. Lim, H. Kim, J. Park, and B. Lee, “Optical beam focusing by a single subwavelength metal slit surrounded by chirped dielectric surface gratings,” Appl. Phys. Lett.92(1), 013103 (2008). [CrossRef]
  16. P. Chen, Q. Gan, F. J. Bartoli, and L. Zhu, “Near-field-resonance-enhanced plasmonic light beaming,” IEEE Photon. J.2(1), 8–17 (2010). [CrossRef]
  17. H. Kim and B. Lee, “Unidirectional surface plasmon polariton excitation on single slit with oblique backside illumination,” Plasmonics4(2), 153–159 (2009). [CrossRef]
  18. Y. Lee, K. Hoshino, A. Alù, and X. J. Zhang, “Efficient directional beaming from small apertures using surface-plasmon diffraction gratings,” Appl. Phys. Lett.101(4), 041102 (2012). [CrossRef]
  19. Y. Lee, A. Alù, and J. X. Zhang, “Efficient apertureless scanning probes using patterned plasmonic surfaces,” Opt. Express19(27), 25990–25999 (2011). [CrossRef] [PubMed]
  20. A. A. Oliner and D. R. Jackson, Antenna Engineering Handbook, 4th ed. (McGraw-Hill, New York, 2007).
  21. C. A. Balanis, Antenna Theory Analysis and Design, 3rd ed. (John Wiley & Sons, 2005).
  22. F. López-Tejeira, S. G. Rodrigo, L. Martín-Moreno, F. J. García-Vidal, E. Devaux, T. W. Ebbesen, J. R. Krenn, I. P. Radko, S. I. Bozhevolnyi, M. U. González, J. C. Weeber, and A. Dereux, “Efficient unidirectional nanoslit couplers for surface plasmons,” Nat. Phys.3(5), 324–328 (2007). [CrossRef]
  23. L. VJ, N. P. Kobayashi, M. S. Islam, W. Wu, P. Chaturvedi, N. X. Fang, S. Y. Wang, and R. S. Williams, “Ultrasmooth silver film deposited with a germanium nucleation layer,” Nano Lett.9, 178–182 (2009).
  24. J. Y. Laluet, A. Drezet, C. Genet, and T. W. Ebbesen, “Generation of surface plasmons at single subwavelength slits: from slit to ridge plasmon,” New J. Phys.10(10), 105014 (2008). [CrossRef]
  25. P. Lalanne, J. P. Hugonin, and J. C. Rodier, “Theory of Surface Plasmon Generation at Nanoslit Apertures,” Phys. Rev. Lett.95(26), 263902 (2005). [CrossRef] [PubMed]
  26. P. Lalanne and J. P. Hugonin, “Interaction between optical nano-objects at metallo-dielectric interfaces,” Nat. Phys.2(8), 551–556 (2006). [CrossRef]
  27. Q. Gan, Y. Gao, Q. Wang, L. Zhu, and F. Bartoli, “Surface plasmon waves generated by nanogrooves through spectral interference,” Phys. Rev. B81(8), 085443 (2010). [CrossRef]
  28. E. Kretschmann and H. Raether, “Radiative decay of non-radiative surface plasmons excited by light,” Z. Naturforsch. A23, 2135–2136 (1968).

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited