플라즈모닉스 - SNU OPEN COURSEWARE

이 병 호

서울대학교 전기공학부

‰ Introduction

‰ Photonic crystals

‰ Vectorial diffractive optics

‰ Plasmonics - Surface plasmon polaritons

‰ Concluding remarks

Contents

Nano

Photonic crystals

Light cavities Light waveguides (‘wires’)

Periodic electromagnetic media Photonic bandgap: optical insulator

Photonic crystals

(a) (b )

(c)

(d) (e) (f)

a : guide b : sharp bend c : add/drop

d : Y-coupler e : filter f : dispersive element

Photonic bandgap waveguides

클래딩 지름 80μm 유효 코어 모드 지름 11.5 μm 전송 손실 (1550nm) 0.35dB/km

허용 곡률 반경 7.5mm

벤딩 손실 (1550nm)

φ 15mm × 10 turn <0.1dB

Mitsubishi Cable

Fujikura

FutureGuide^®-SR15

→허용 곡률 반경 15 mm FutureGuide^®-SR7.5

→ 허용 곡률 반경 7.5 mm

Holey fibers

Two categories of diffractive optics

Vectorial diffractive optics

Scalar diffractive optics

1. Homogeneous medium (free space)

2. Large scale structures ( )

> 10 λ

1. Inhomogeneous medium

(photonic crystals, holograms, plasmonic devices)

2. Small scale structures ( )

< 10 λ

- Electromagnetic theory - Non-paraxial regime - Rigorous modeling of

diffractive elements

- Scalar diffraction theory - Paraxial regime

- Approximate modeling of diffractive elements

‰ FDTD is a rigorous analysis method with widely applications from nano- to all length-scales using the Maxwell’s equations and curl equations

(i,j,k) (i,j,k+1)

Ez

y

(i,j+1,k)

(i -1,j+1,k)

Ex Hz

Hx

Hy

Ez Ez

Ez

Ex E x

Ex

Hz

Ey E

y

Ey Ey

Hy

Hx

x z

1 *

y z x

y y

y

H E E

t x z σ H

μ

∂∂ = ⎛⎜⎝∂∂ −∂∂ − ⎞⎟⎠ 1 y *

x z

x x

x

H E E

t z y σ H

μ

⎛∂ ⎞

∂∂ = ⎜⎝ ∂ − ∂∂ − ⎟⎠

1 x y *

z

z z

z

E E

H H

t y x σ

μ

⎛∂ ∂ ⎞

∂∂ = ⎜⎝ ∂ − ∂ − ⎟⎠

1 x y

z

z z z

H H

E E

t y x σ

ε

⎛∂ ∂ ⎞

∂∂ = ⎜⎝ ∂ − ∂ − ⎟⎠

y 1 z x

y y y

E H H

t x z σ E

ε

∂∂ = ⎛⎜⎝∂∂ − ∂∂ − ⎞⎟⎠

1 y

x z

x x x

E H H

t z y σ E

ε

⎛∂ ⎞

∂∂ = ⎜⎝ ∂ − ∂∂ − ⎟⎠

3D Yee’s cell geometry

Finite-difference time-domain (FDTD) method

Ex – component Ey – component

Extension to three-dimensional solid immersion lens nano-focusing for high

density optical memory

Solid immersion lens simulation (FDTD)

Frequency domain method for the Maxwell equations

( ) ( )

0 , , ˆ _x ˆ _y ˆ _z

E jwμ μ x y z xH yH zH

∇× = + +

( ) ( )

0 , , ˆ _x ˆ _y ˆ _z

H jwε ε x y z xE yE zE

∇× = − + +

Homogeneous Maxwell equations in the spatial domain

The Maxwell equations in the spatial domain have partial differential operators. But Maxwell equations in the frequency domain are

described by several algebraic equations.

( ) ( )

( )

( )

( )

( )

0

0 0 0 0 0

0 0 0 0

0 0 0 0 0

0 0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0

0 0 0 0 0

0 0 0 0

0 0 0 0 0

x

z y

x x

y

z x

y y

z z y x z

x x z y x

z x

y y

y

y x

z z

z

jK jK

E E

jK jK

E E

jK jK

E E

k H jK jK H

jK jK

H H

jK jK

H H

ε ε

ε

μ

μ

μ

⎡ ⎤

⎡ − ⎤

⎡ ⎤ ⎡

⎢ ⎥

⎢ ⎥

⎢ ⎥ ⎢

⎢ ⎥⎢ ⎥ ⎢ − ⎥

⎢ ⎥

⎢ − ⎥

⎢ ⎥

⎢ ⎥

= ⎢ ⎥

⎢ ⎥

⎢ ⎥⎢ ⎥ ⎢ − ⎥

⎢ ⎥

⎢ ⎥

⎢ ⎥

⎢ ⎥ −

⎢ ⎥

⎢ ⎥

⎢ ⎥⎢⎣ ⎥ ⎢⎦ − ⎥⎣

⎢ ⎥ ⎣ ⎦

⎣ ⎦

⎤⎥

⎢ ⎥

⎢ ⎥

⎢ ⎥

⎢ ⎥

⎢ ⎥

⎢ ⎥

⎢ ⎥⎦

Homogeneous Maxwell equations in the (spatial) frequency domain

Fourier

transform

Rigorous coupled wave analysis (RCWA)

i

layer (i+1)

layer

( )^{i M N x mn}( )^{i, ( )} ( )^{y mni, ( ) z mn}( )^{,i ( ) exp}

(

)

m M n N

E xS z yS z zS z j k x k y

=− =−

⎡ ⎤ ⎡ ⎤

=

∑ ∑

( ) ⁰ ( ), ( ), ( ),

(

)

0

( ) ( ) ( ) exp

M N

i i i i

x mn y mn z mn x m y n

m M n N

H j ε xU z yU z zU z j k x k y

μ _{=− =−} ^{⎡ ⎤ ⎡ ⎤}

=

∑ ∑

( ) ( )

, ,

,

( , ) exp ( )

i i

gh x g x h

g h

x y j G x G y

ε =

∑

Fourier representation of the EM fields in the i^th layer Structure modeling (staircase approximation)

Fourier representation of the permittivity of the i^th layer

RCWA examples

2D-binary dielectric grating showing polarization-dependent diffraction

TM-polarization TE-polarization

RCWA examples

•• Modal analysis of dielectric waveguideModal analysis of dielectric waveguide

-- The eigenmodeThe eigenmode extraction from total-extraction from total-field by observing the field by observing the eigenvalueeigenvalue..

Total field

Total field EigenmodeEigenmode

RCWA examples

3D micro-pyramid structure (15 level staircase approximation)

x-y crosssection

Ey

x-y crosssection

Ex

Wavelength(λ)=532nm Period=3λ, Height=6λ Normal incidence

RCWA examples

3D micro-metal-sphere structure (15 level staircase approximation)

E_y E_y E_z

E_z

E_x E_x

Pseudo-Fourier modal analysis (PFMA)

( )

( (

) )

2 2 2

, , exp

M N H

stp x stp y stp z stp

s M t N p H

x y z j k x k y k z

ε ε

=− =− =−

=

∑ ∑ ∑

( ^{,0 ,0 ,0} )

(

) ( (

) )

, ,

e^{j kx x ky y kz z} _{x m n q y m n q z m n q} exp _{x mnq y mnq z mnq}

m n q

E x E y E z j k x k y k z

+ +

=

∑

Ek

Pseudo-Fourier representation of the E-M field

Maxwell equation in the PFMA

Structure modeling (3D Fourier series)

( ) ( ) ( )

( ) ( ) ( )

( ) ( ) ( )

( ) ( ) ( )

1 1

1 1

,0

1 1

0

1 1

0 0

0 0

z y z x x y z y

y y

z y x z x x z y x z x

y y

y z x x y z y z

x x

x x x y z

y z z

jG K K K K

E E

jG K K K K E jk E

H k H

K K K K jG

H H

K K K K jG

ε μ ε

μ ε ε

μ ε μ

ε μ μ

− −

− −

− −

− −

⎡ − − ⎤⎡ ⎤ ⎡ ⎤

⎢ ⎥

⎢ ⎥ ⎢ ⎥

− − + −

⎢ ⎥

⎢ ⎥ ⎢ ⎥

⎢ − − ⎥⎢ ⎥= ⎢ ⎥

⎢ ⎥

⎢ ⎥ ⎢ ⎥

⎢− + − − ⎥ ⎢ ⎥⎣ ⎦ ⎢⎣ ⎥⎦

⎢ ⎥

⎣ ⎦

Eigenvalue

Eigenmode profile

PFMA example

Longitudinally periodic and finite 2D photonic crystals

g g

=

∑

E E Total field distribution is a superposition of pseudo-Fourier eigenmodes with appropriate coupling coefficients.

Wavelength(λ)=532nm Period=1.2λ, radius=0.4 λ Normal incidence

Comparison

FDTD RCWA PFMA

Domain Space Frequency Frequency

Field representation Finite-difference method Piles of truncated 2D- pseudo-Fourier series

Truncated 3D-pseudo- Fourier series Structure modeling Mesh-structure Staircase approximation

& piles of 2D-Fourier series

3D-Fourier series (no staircase approximation) Aperiodic structure

Analysis

Yes No

(If using PML, yes)

No

(If using PML, yes) Evanescent field

analysis

No (Cannot separate) Yes Yes

Modal analysis No No Yes

Computation cost Very huge Large Huge

Parallel computing

Parallel computing system Parallel computing system

Master Master

AMD

Athlon MP

‰ Parallel computation based on Linux MPI

‰ 16 × AMD MP 2000+ CPU

‰ 32G memory

‰ 1Gbps network

‰ MPI and Scalapack library for parallel linear algebra

node 1

node 2

node 3

node 4 Total

30 layers

10 layers

MPI 1 layer Total 4 nodes

node 1 : master / node 2,3,4 : slave

What is a plasmon?

− “Plasma-oscillation”: density fluctuation of free electrons

Plasmonics

The Lycurgus Cup (glass) British Museum

4th century A.D.

“Labors of the Months“Labors of the Months”” Norwich, England Norwich, England

ca. 1480 ca. 1480

+ + +

- - - + - +

k

Bulk plasmon

Surface plasmon

Confined plasmon in nanoparticle

Green when illuminated from outside and red when illuminated from within the cup due to very small amounts of gold powder about 40 parts per million)

The ruby color is attributed to gold nanoparticles.

Surface plasmon (SP)

- EM surface-bound wave between a metal and dielectric surface (p- polarized, TM wave)

- The metal behaves like a plasma, having equal amounts of positive and negative charges, of which the electrons are mobile.

- The bound wave has an evanescent field which decays exponentially perpendicular to the surface.

- SPs can be produced by photons in the attenuated total reflection device.

- SPs have played a significant role in a variety of areas of fundamental and applied research, from surface sensitive technique to surface plasmon resonance microscopy and a wide range of photonic applications.

Metal Dielectric

x z

+++ - - - +++

H_y

• E

z

|E_z| δ_m

δ_d

k_x

ω ω=ck

ω

k_SP k₀

Surface plasmon

- Dispersion of SP

- Propagation length, δ_SP

ex) for silver-air interface, k_sp= 1.03k_o

ex) for silver-air interface, δ_SP=20 μm

m d

m d m

d m d

SP k c

k ε ε

ε ε ω ε ε

ε ε

= +

= ₀ +

( )

m m d

m d m SP

SP

c

k ε

ε ε

ε ε ε δ ω

′′

⎟⎟ ′

⎠

⎜⎜ ⎞

⎝

⎛

′

′ +

′′ =

= ^{2 2}

3

2 1

‰ Excitation methods

− Kretschmann geometry, Otto geometry, SNOM probe

− Diffraction grating, bumped metal surfaces

SPP excitation configurations θ_sp

z

θ_sp1 θ_sp2

θ_sp

Surface plasmon excitation

Surface plasmon

Confined SPs in Nanoparticles

− Particle can be considered as a dipole

- Uniform sphere, spheroid, rod shaped metal nano-particles - Interaction between particles, plasmonic chains

- Focusing and guidance of light at nanometer length scales

Surface plasmons in nanoparticles

Electric polarizability of a sphere α

0 3

0

2

4 R E

p

m

m

G

G ε

ε ε

ε πε ε

+

= −

4

2

m m

R ε ε α πε

ε ε

= −

+

ε= ε₁(ω)+iε₂(ω)

Dielectric constant of the metal particle

ε_m: Dielectric constant of the embedding medium. Usually real and taken

independent of frequency.

Bohren and Huffman (1983), p.136

minimum

= + ε_m ω

ε( ) 2 _Æ Negative real dielectric constant ε₁(ω)

Resonant enhancement of p if

SiO₂

Ag SiO₂ E_z

SP excited

EM wave is coupled to the plasma oscillations of the surface charges

( )

(

)

d

z

e

E t

z x

E G , , = G

(

)

i m

m

z

e

E t

z x

E G ( , , ) = G

For propagating bound waves:

- k_xis real

- k_z is imaginary x

z

Surface plasmon polariton

10㎛

Optical waveguide

core size : ~ 10 μm

Semiconductor IC

line width : ≤ 100 nm

Semiconductor IC

line width : ≤ 100 nm 100㎚

R xΔ L xΔ

R xΔ L xΔ

…

Rin

( )

v to

C0

( )

uin t

CMOS VLSI RLC transmission line interconnection

50%

50% signal propagation delay

(Ismail-Friedman formula) T

Surface plasmon polariton wave propagation

Coupled RLC resonator transmission line

R xΔ L xΔ R xΔ

L xΔ

R xΔ L xΔ

…

50%,

c,CMOS

1 T CMOS

∝ω

50%,

c,SPP

1 T SPP

∝ω

50%, 50%,

> T _CMOS T _SPP

R xΔ L xΔ

R xΔ L xΔ

…

Rin

( )

v to

C0

( )

uin t R xΔ

L xΔ R xΔ

L xΔ

…

Rin

( )

v to

C0

( )

uin t

CMOS VLSI RLC transmission line interconnection

50%

50% signal propagation delay

(Ismail-Friedman formula) T

Surface plasmon polariton wave propagation

Coupled RLC resonator transmission line

R xΔ L xΔ R xΔ

L xΔ

R xΔ L xΔ R xΔ …

L xΔ R xΔ

L xΔ R xΔ

L xΔ R xΔ

L xΔ R xΔ

L xΔ R xΔ

L xΔ

R xΔ L xΔ R xΔ

L xΔ

…

50%,

c,CMOS

1 T CMOS

∝ω

50%,

c,SPP

1 T SPP

∝ω

50%, 50%,

> T _CMOS T _SPP

Surface plasmon

line width : ≤ 50 nm

Surface plasmon

line width : ≤ 50 nm

Transmission model

H. Ditlbacher et al., “Silver Nanowires as Surface Plasmon Resonators,” Physical Review Letters 95, pp.257403, 2005.

Surface plasmon dispersion relation

ω

ω_p

d p

ε ω

+ 1

Re k_x

real k_x real k_z

imaginary k_x real k_z

real k_x

imaginary k_z

d

ckx

ε

Bound modes Radiative modes

Quasi-bound modes

Dielectric: ε_d

Metal: εx _m= ε_m^'+ ε_m^"

z

(−ε_d < ε'_m

< 0)

(ε'_m < −ε_d) (ε'_m>

0)

2 / 1

⎟⎟ ⎠

⎜⎜ ⎞

⎝

⎛

= +

d m

d m

x

c

k ε ε

ε ε ω

large k

small wavelength

X-ray wavelengths at optical frequencies Ar laser:

λ_vac= 488 nm λ_diel = 387 nm λ_SP = 100 nm 3.4 eV

(360 nm)

dielectric dielectric

metal metal

bounded mode bounded mode

zz

xx

In metal, z<0

1 1 1

1 1 1 1

(0, , 0) exp[ ( )]

( , 0, ) exp[ ( )]

y x z

x z x z

H H j k x k z

E E E j k x k z

= −

= −

JJG JG

In dielectric, z>0

2 2 2

2

(0, , 0) exp[ ( )]

( , 0, ) exp[ ( )]

y x z

H H j k x k z

E E E j k x k z

= +

= +

JJG JG

Using the

continuity relation

1 2

0 1 2

ksp

c

ε ε ω

= ε ε

+ ε1

ε2

Semi-infinite metal structure

Surface plasmon dispersion relation

Surface plasmon dispersion relation

die2die2

metal metal

die1die1

die2die2

metal metal

die1die1

bound mode

bound mode radiation moderadiation mode zz

xx

dd

1 2 1 2

1 2 1 2

Char. eqn. : ^{m z} 1 ^{m z} 1 ^{m z} 1 ^{m z} 1 exp( 2 _zm )

zm zm zm zm

k k k k

k k k k k d

ε ε ε ε

ε ε ε ε

⎛ ⎞⎛ ⎞ ⎛ ⎞⎛ ⎞

+ + = − − −

⎜ ⎟⎜ ⎟ ⎜ ⎟⎜ ⎟

⎝ ⎠⎝ ⎠ ⎝ ⎠⎝ ⎠

1 2 1 2

1 2 1 2

let ( )_x ^{m z} 1 ^{m z} 1 ^{m z} 1 ^{m z} 1 exp( 2 _zm )

zm zm zm zm

k k k k

f k k d

k k k k

ε ε ε ε

ε ε ε ε

⎛ ⎞⎛ ⎞ ⎛ ⎞⎛ ⎞

= ⎜ + ⎟⎜ + −⎟ ⎜ − ⎟⎜ − ⎟ −

⎝ ⎠⎝ ⎠ ⎝ ⎠⎝ ⎠

Finite metal slab structure

S. Kitson, PRL, 77, 2670, (1996)

S. Bozhevolnyi, PRL, 86, 3008, (2001)

Metal surface relief gratings

and pulses in TIR geometry

Finite metal slab structure

x y

At metal surface At metal surface

x y

22σσ_ss=₌22μμm_m 22σσ_tt=₌22fsfs T=T=5050fsfs

x

z

22σσ_ss=2₌2μμm_m

2020μμ_mm Surface

plasmon

Damping radiation

Surface

Surface plasmonplasmon excited by Gaussian beamexcited by Gaussian beam

Surface plasmon excitation by NSOM tips

x

z

-4 -3 -2 -1 0 1 2 3 4

x 10^-6 0

1

2

3

4

5

6

7

8

9 x 10^-6

2μm

6μm

n_core

=1.76 n_clad=1.46

x

z

-4 -3 -2 -1 0 1 2 3 4

x 10^-6 0

1

2

3

4

5

6

7

8

9 x 10^-6

x

z

-4 -3 -2 -1 0 1 2 3 4

x 10^-6 0

1

2

3

4

5

6

7

8

9 x 10^-6

2μm 2μm

6μm6μm

n_core

=1.76 n_clad=1.46

Intensity

x

z

-4 -3 -2 -1 0 1 2 3 4

x 10^-6 0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1 x 10^-5

AirAir

Ag 40nm Ag 40nm n=2n=2

n=0.7 n=0.7

Regenerated surface plasmon

50μm

Gaussian beam by a dielectric grating coupler

Beaming light from a

Beaming light from a subwavelength subwavelength aperture aperture

H. J. Lezec, A. Degiron, E. Devaux, R. A. Linke, L. Martin-Moreno, F. J. Garcia-Vidal, T. W. Ebbesen, Science, vol. 297, no. 2, pp. 820-822, 2002.

Light usually diffracts in all directions when it emerges from a subwavelength aperture, which puts a lower limit on the size of features that can be used in photonics. This limitation can be overcome by creating a periodic texture on the exit side of a single aperture in a metal film. The transmitted light emerges from the aperture as a beam with a small angular divergence

Surface

Surface plasmon plasmon subwavelength subwavelength optics optics

W. L. Barnes, A. Degiron, and T. W. Ebbesen, Nature, vol. 424, pp. 824-830, 2003.

Bull’s eye structure- beaming light by subwavelength structures

2~32~3μμm_m

25mm25mm

Slit flanked by 10 grooves (periodically distributed) at each side (geometrical parameters:

slit and grooves widths 40nm, groove depth: 100 nm, groove period: 500 nm, working wavelength: 560 nm).

Metal-gap waveguide with bottom surface grating

λ λ =532 =532 nm, nm, TM TM

grating period / width / height grating period / width / height

= 500

= 500nmnm / 250nm/ 250nm / 80nm/ 80nm

x

z

Ag clad Ag clad n=1.52n=1.52

surface grating

surface grating flat surfaceflat surface Reflection is

Reflection is decreased decreased

Metal-gap waveguide analysis

•• Metal-Metal-gap waveguide with upper surface gratinggap waveguide with upper surface grating

λ λ =532 =532 nm, nm, TM TM

Ag clad Ag clad

x

z

grating period / width / height grating period / width / height

= 500

= 500 nmnm/ 250 / 250 nmnm / 80 nm/ 80 nm

Surface grating

Metal-gap waveguide analysis

x [um]

z [um]

-10 -5 0 5 10

0

5 10 15 20

25 ^{-300 -2000 -100 0 100 200 300}

2 4 6 8

x 10^{- 3}

Diffraction order

|T x|

components components

①

②

-300 -2000 -100 0 100 200 300 2

4 6 8

x 10^{- 3}

Diffraction order

|T x|

components components

①

②

x [um]

z [um]

-10 -5 0 5 10

0 5 10 15

20

25 _-300⁰ _{-200 -100 0 100 200 300}

2 4 6 8

x 10^-3

Diffraction order

|T x|

propagation components

evanescent components

① ②

③

-3000 -200 -100 0 100 200 300 2

4 6 8

x 10^-3

Diffraction order

|T x|

propagation components

evanescent components

① ②

③

diverging converging

x

z 100 nm Ag

Grating D, E Grating A, B

diverging converging

x

z 100 nm Ag

Grating D, E Grating A, B

x

z ^{100 nm}

Ag

Grating C

x

z ^{100 nm}

Ag

Grating C

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,”Applied Physics Letters, vol. 90, no. 5, 051113, 2007.

K. G. Lee, H. W. Kihm, J. E. Kihm, W. J. Choi, H. Kim, C. Ropers, D. J. Park, Y. C. Yoon, S. B. Choi, D. H. Woo, J. Kim, B. Lee, Q. H. Park, C. Lienau, and D. S. Kim, “Vector field microscopic imaging of light,”Nature Photonics, vol. 1, no. 1, pp. 53-56, 2007.

P-Polarized Light

Prism Ligands

Proteins

SPR biosensors

10 20 30 40 50 60 70 80 90 0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

theta_m = 37.9

Inc ident angle(degree)

Reflectance

0 . 4 0 . 6 0 . 8 1 1 . 2 1 . 4 1 . 6 1 . 8 2

a b s ( E x )

1 1 . 5 2 2 . 5 3 3 . 5 4 4 . 5 5

a b s ( E z )

SF10

SF10: 1.732

@633nm

Au :30nm He-Ne 633nm

E_z

E_x E_y

Experimental result

Simulation result

Surface plasmon resonance on a flat boundary

Multiple SPR on multilayer structures

AZ1512 (4000

rpm for 30sec) AZ 1512 (3000 rpm for 30sec)

AZ 1512 (2000 rpm for 30sec) AZ 1512 (1000 rpm for 30sec)

White light source (Halogen lamp) White light source

(Halogen lamp)

Fiber bundle coupler Fiber bundle coupler

Spatial filter Spatial filter

Bi convex lens Bi convex lens

Plano convex lens Plano convex lens

Polarizer Polarizer

ATR device ATR device

Couplig optics Couplig optics Spectrometer

Spectrometer MirrorMirror

Rotational stage Rotational stage

Visualization of SPR using R-TMM and Gaussian angular spectrum decomposition

SPR analysis

8874, 2005.

‰ SPP Applications

- Surface sensitive techniques, SPR microscopy - SPR technologies and a wide range of

photonic ICs.

Waveguides of surface plasmons Surface plasmon Bragg reflectors Bio- and flow-sensors using SPR Light transmission enhancement Laser beam shaping

Surface plasmon applications

A. Degiron et al. Appl. Phys. Lett. 81,4327 (2002).

Ag Film with hole arrays (Period = 300, 450, 550nm Hole diameter=155,180,225nm)

J. C. Weeber et al., Phys. Rev. B 64, 045411(2001).

40 nm thick, 2.5 μm wide gold stripe lying on a glass substrate

2.5 μm 30 μm

Plasmonic

Plasmonic nanolithography nanolithography

W. Srituravanich, N. Fang, C. Sun, Q. Luo, and X. Zhang, Nano Letters, vol . 4, no. 6, pp. 1085-1088, 2004.

Surface plasmons

1. Much shorter wavelength compared to the excitation light wavelength

2. E-field intensity of surface plasmons can be boosted by several orders of magnitude Metal mask : 90nm holes, 170nm period

Nano metal rod memory

Reading at 760nm

690nm

950nm Spindle

Nano Metal Rod

R/W Lights w.r.t. Stectrums

Swinburne University of Technology

Resonant surface plasmon couplings (SuperLens)

Superlens-based nanopatterning

- A flat plane of NRM behaves as superlens and amplifies evanescent waves in near-field through a series of plasmon resonances.

- This allows super-resolutions below diffraction limit.

- Experimentally achieved improvements in UV range: 5-10x beyond the operating wavelength - Applicable for direct imaging of evanescent modes, thus for immediate recognition of analytes - Also applicable for nanopatterning through subwavelength contact lithography

UV exposure (365nm)

d2

Thin silver film

Resonant surface plasmon couplings (LED)

Ultrahigh efficiency LED via plasmon light extraction

46x PL enhancement for wafers with periodicities of 480nm and 650nm.

Nanodot focusing array

(A) SEM image of a nanodot focusing array coupled to a 250-nm-wide Ag strip guide.

(B) NSOM image of the SP intensity showing subwavelength focusing.

W. Nomura, M. Ohtsu, and T. Yatsui, Appl. Phys. Lett. 86, 181108 (2005).

Plasmonic toolbox: ω, e(ω), d - engineer λ(ω)

Plasmonic modulator & IC

Plasmonic resonator & laser Plasmonic Bragg mirror & waveguide

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