Surface magneto-plasmons in magnetic multilayers - Walther ...

Section 2.2
Dispersion relation 11
Further, it is noted that surface plasmons can only be excited by p-polarised light
(electric field vector parallel to the incident plane). This is obvious since surface
plasmons are longitudinal oscillations and therefore only an electric field which has a
parallel component to the propagation direction, can excite those oscillations.
ω [s -1 ]
4x10 16
3x10 16
1x10 16
2x10 16
ω
p
ω
sp
0
4x10 16
3x10 16
2x10 16
1x10 16
k
(a)
(c)
k
εprism θ
εAu εdielectric kc/sinθ√ε prism
0 5x10 7
0
Au-Air
Au-Air
c sin(θ)
( )
/ √ε 0
( )
c/√ε 0
1x10 8
(b)
(d)
k
k
k
0 5x10 7
k x [m -1 ]
εAu εdielectric θ
ε θ
prism
εAu εdielectric kc/sinθ√ε prism
Au-Air
/
Au-Air
c sin(θ)
c sin(θ)
c
( )
/ √ε 0
( )
c/√ε 0
Au-Glass
1x10 8
4x10 16
3x10 16
2x10 16
1x10 16
0
4x10 16
3x10 16
2x10 16
1x10 16
Figure 2.2: Dispersion relation of surface plasmons. The black line ( )is the dispersion
relation for a gold-air interface. The red line ( ) is the dispersion relation for
light with k-vector parallel to the interface. The dotted red line ( ) is the
dispersion relation for light under the incident angle θ. The blue lines are the
dispersion relations for light coupled through a prism, parallel to the interface
( ) and under the incident angle θ ( ). And the magenta line ( ) is the
dispersion relation for a glas-gold interface. The inset in the upper left shows
the Kretschmann configuration with the k vectors for the incident light and
the surface plasmons.
2.2.1 Kretschmann-Raether configuration
As mentioned above it is possible to excite surface plasmons when the light is coupled
into a prism before it is reflected at the metal interface.
This method was first introduced by Erwin Kretschmann and Heinz Raether in 1968
0