Beam manipulation via plasmonic structure

Kwang Hee, Lee2010. 5. 19

Photonic Systems Laboratory

Photonic Systems Lab School of EECS, S.N.U.

Contents

• Introduction of surface plasmon polariton(SPP)

• Extraordinary transmission(EOT)

• Effect factors of transmission

• Exit patterning

• Summary

Photonic Systems Lab School of EECS, S.N.U.

What is the SPP?

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2

1

1

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Evanescent modes

+ +

ze 1

ze 2

x

Metal

Dielectric

+ + + + - - - -

2

1

+ +

z

Photonic Systems Lab School of EECS, S.N.U.

SPP at a single interface

Photonic Systems Lab School of EECS, S.N.U.

Where can SPP be used?

Integrated electro-photonics, will remove the crosstalk and Ohmic loss of Electronics

meanwhile retaining the nano-features of Electronics

Photonic Systems Lab School of EECS, S.N.U.

EOT

• Extraordinary Transmission (EOT) Sub-wavelength hole arrays : peak at above a0

contribution of surface modes Due to grating coupling at regular, periodic lattice

Phase matching condition

Ebbesen, T. W., Lezec, H. J, Ghaemi, H. F., Thio, T., and Wolff, P. A. “Extraordinary optical transmission through sub-wavelength hole arrays.” Nature, 931:667–669. 1998.

Photonic Systems Lab School of EECS, S.N.U.

EOT

• Extraordinary Transmission (EOT) EOT occurs at another structures : Bull’s eye, square dimple

array, slit array

Thio, Tineke, Pellerin, K. M., Linke, R. A., Lezec, H. J., and Ebbesen, T. W. “Enhanced light transmission through a single subwavelength aperture.” Opt. Lett., 26(24):1972–1974. 2001.Porto, J. A., Garcia-Vidal, F. J., and Pendry, J. B. “Transmission resonances on metallic gratings with very narrow slits.” Phys. Rev. Lett., 83(14):2845–2848. 1999.

Photonic Systems Lab School of EECS, S.N.U.

Effect factors of transmission

• Factor for Surface Plasmon Polaritons (SPP)– Flim thickness : T saturation for small thickness (order of

skin depth)– Hole width : T increases and the peaks broaden for increas-

ing hole width

Degiron, A., Lezec, H. J., Barnes,W. L., and Ebbesen, T.W. “Effects of hole depth on enhanced light transmission through subwavelength hole arrays.” Appl. Phys. Lett., 81(23):4327–4329. 2002.van der Molen, K. L., Segerink, F. B., van Hulst, N. F., and Kuipers, L. “Influence of hole size on the extraordinary transmission through subwavelength hole arrays.” Appl. Phys. Lett., 85(19):4316–4318. 2004.

Photonic Systems Lab School of EECS, S.N.U.

Effect factors of transmission

• Factor for Surface Plasmon Polaritons (SPP)– Coupled cavity modes in the grooves

• h : about frequency• d : about in-phase re-emmision

– Exit side grooves don’t influence T

García-Vidal, F. J., Lezec, H. J., Ebbesen, T. W., and Martín-Moreno, L. “Multiple paths to enhance optical transmission through a single subwavelength slit.” Phys. Rev. Lett., 90(21):213901. 2003.

Photonic Systems Lab School of EECS, S.N.U.

Effect factors of transmission

• Localized Surface Plasmons (LSP)

In contrast to PEC case, the maximum in the transmission of real metal near 580 nm can be associated with the excitation of a localized surface plasmon.the nanohole excitation decays not only into scattered light, but into surface plasmon polaritons.

Chang et al.,“Surface plasmon generation and light transmission by isolated nanoholes and arrays of nanoholes in thin metal films”, Opt. Express, Vol.13, No.8, 3150, 2005.

Photonic Systems Lab School of EECS, S.N.U.

Effect factors of transmission

• Localized Surface Plasmons (LSP)

Charges accumulate at the edges with a length scale of one wavelength. This increasing charge density enhances the electric field.

The electric field is proportional to the charging time or equivalently 1/f.

Seo et al.,“Terahertz field enhancement by a metallic nano slit operating beyond the skin-depth limit”, Nature Photonics, Vol.3,No.3,152-156, 2009.

Photonic Systems Lab School of EECS, S.N.U.

Effect factors of transmission

• Waveguide resonance

F.J.Garcia-Vidal et al., “Transmission of Light through a Single Rectangular Hole” , PRL, 95, 103901, 2005.

Normalized-to-area transmittance at resonance is proportional to the aspect ratio, and to the dielectric constant inside the hole.

A transmission peak develops at approximately λc=2ay, with increasing maximum transmittance and decreasing linewidth as ay/ax increases.

Photonic Systems Lab School of EECS, S.N.U.

Exit surface patterning

• Exit surface patterning enables directional emission

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

Photonic Systems Lab School of EECS, S.N.U.

Exit surface patterning

• Narrow beam profile is obtained with about 10 grooves

Martín-Moreno, L., Garcia-Vidal, F. J., Lezec, H. J., Degiron, A., and Ebbesen, T. W. “Theory of highly directional emission from a single subwavelength aperture surrounded by surface corrugations.” Phys. Rev. Lett., 90(16):167401. 2003.

Photonic Systems Lab School of EECS, S.N.U.

• Off-axis beaming with asymmetric surface gratings

Exit surface patterning

Seyoon Kim, Hwi Kim, Yongjun Lim, and Byoungho Lee, “Off-axis directional beaming of optical field diffracted by a singlesubwavelength metal slit with asymmetric dielectric surface gratings” Applied Physics Letters 90, 051113, 2007

Photonic Systems Lab School of EECS, S.N.U.

• Near-field optical probe(conical geometry)

• Micro-fluidic detector

Applications

Drezet et al., “Extension of Bethe’s diffraction model to conical geometry” ,Europhys. Lett., 54(6), pp. 736-740, 2001. Bravo-Abad et al., “Transmission properties of a single metallic slit” ,Physical Review E, 69, 026601, 2004.

ε=1.8978

ε=2.2506

Photonic Systems Lab School of EECS, S.N.U.

• Optical switching using nonlinear material

Applications

Porto et al., “Optical bistability in subwavelength slit apertures containing nonlinear media”, Phys. Rev. B, 70, 081402, 2004.

The transmission spectra differ for increasing and decreasing fluxes.

d=0.75, a=0.05, h=0.45 um

Optical bistability

Photonic Systems Lab School of EECS, S.N.U.

Summary

• SPP has a great possibility to integrate electronics and photonics

• Extraordinary transmission is generated from SPP which is influenced by geometrical parameters.

• Transmission is also influenced by LSP and waveguide resonance.

• With exit surface patterning, directional emmision and off-axis beaming can be possible.

• EOT is applicable to various optical devices such as switch, probe and so on.