Lecture 13 – Nanophotonics in plasmonics

EECS 598-002 Winter 2006Nanophotonics and Nano-scale Fabrication

P.C.Ku

2EECS 598-002 Nanophotonics and Nanoscale Fabrication by P.C.Ku

Schedule for the rest of the semesterIntroduction to light-matter interaction (1/26):

How to determine ε(r)? The relationship to basic excitations.

Basic excitations and measurement of ε(r). (1/31)Structure dependence of ε(r) overview (2/2)Surface effects (2/7):

Surface EM waveSurface polaritonsSize dependence

Case studies (2/9 – 2/16):Quantum wells, wires, and dotsNanophotonics in microscopyNanophotonics in plasmonics

Dispersion engineering (2/21 – 3/7):Material dispersionWaveguide dispersion (photonic crystals)

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Outline

Today, we will discuss the applications of surface plasmon polaritons in the following areas.

SensingNanoscale light guidingNanolithographyLED efficiency enhancement

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Surface plasmon for sensing

Ref: Prasad, Biophotonics, figures 9.23 and 9.24.

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Bio sensing

Ref: Prasad, Biophotonics, figure 9.25.

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Surface plasmon polariton (SPP) confinement

dielectric

metal

~100nm

~10nm

Most of the energy is confined in the dielectric side.

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Plasmonic planar waveguide

Ref: J. R. Krenn and J. C. Weeber, Phil. Trans. R. Soc. Lond. A 362 (2004) 739.

L

W

λ=633 nm

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Interference

Ref: J. R. Krenn and J. C. Weeber, Phil. Trans. R. Soc. Lond. A 362 (2004) 739.

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Plasmonic nanoparticle waveguide

λ=1.55µm. Propagation length = 50µm.

Ref: S. Maier et al., Appl. Phys. Lett., 86 (2005) 071103.

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Plasmonic V-groove waveguide

Ref: S. Bozhevolnyi et al., Phys. Rev. Lett., 95 (2005) 046802.

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Another example of coupler

Ref: W. Nomura et al., Appl. Phys. Lett., 86 (2005) 181108.

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Plasmonic printing

Ref: P. G. Kik et al., Proc. Of SPIE, 4810 (2002) 7.

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Ref: P. G. Kik et al., Proc. Of SPIE, 4810 (2002) 7.

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Line/space pattern

Ref: X. Luo and T. Ishihara, Appl. Phys. Lett., 84 (2004) 4780.

2mm

Interference of SPPgenerates extra fringes

Mask pitch 300nm

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g-line (436 nm)

Ref: X. Luo and T. Ishihara, Appl. Phys. Lett., 84 (2004) 4780.

The authors attributed the LER tothe mask roughness.

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Superlens version

Ref:N. Fang et al., Science, 308 (2005) 534.

I-line (365 nm)

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Ref:N. Fang et al., Science, 308 (2005) 534.

Negative resist~ 120 nm thick beforeprinting

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Spontaneous emission enhancement

Corrugated metal can coupleSP to radiation.

Ref: K. Okamoto et al., Appl. Phys. Lett., 87 (2005) 071102.

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Top-emitting organic LEDs

Ref: S. Wedge et al., Appl. Phys. Lett., 85 (2004) 182.

Active layer Alq3 ispumped by a diodelaser @ 410 nm fromthe bottom silica sub.

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MDPC = metallic-dielectric photonic crystal

L/S=150/150 nm

Ref: C. Liu et al., Appl. Phys. Lett., 86 (2005) 143501.

Active layer MEH-PPVis electrically pumped.

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Radiative lifetime shortening in fluorescence process

Reduce the risk of photochemical destruction when molecules are in excited states for long time.Enhance quantum yield

Ref: D. A. Weitz et al., Opt. Lett., 7 (1982) 89.

τ=2 µs

w/o Ag: τ=280 µs

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Directional fluorescence

Ref: J. R. Lakowicz et al., J. Phys. D, 36 (2003) R240.

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Recommended Readings

Plasmonic biosensingP. N. Prasad, Biophotonics

Plasmonic waveguideE. Ozbay, Science, 311 (2006) 189.

Plasmonic printingP. G. Kik et al., Proc. Of SPIE, 4810 (2002) 7.