Surface Plasmon Polaritons (SPPs) - Introduction and basic properties

metal/air
interface
E
( x)
k
x
ω
= k′
+ ′
x ikx
=
c
ik xx ik′
x x −k
x′
′ x
= E0e
= E0e
e
propagating term exponential decay
in x-direction
L
x
1
=
2k′
′
x
SP propagation length
ε m
ε + 1
m
propagation
length
intensity !
ε d
= 1
2
ω p
ε m = 1−
2
ω + iγω
γ = 0.
2
10
7.5
5
2.5
-2.5
-5
-7.5
-10
Lx( λvac)
ε ′′ m
ε ′ m
Drude
model
0.4 0.6 0.8 1
ω p
ωSP
=
2
200 ε = −1
= 514. 5 nm : Lx
= 1060 nm : Lx 22 μ
500 μm
20
10
5
2
1
0.2 0.4 0.6 0.8 ω
ω 1 p
Example silver: λ = m
λ =
100
50
ω
ω p