
95Materials for Nanosensors
line. All light is reected at incident angles >θ
c
. If a semitransparent noble
metal lm is placed at the interface (Figure 2.3b), then under conditions
of total internal reection, SPR occurs. This is commonly known as the
Kretschmann conguration.
The condition of surface plasmon resonance will occur when the following con-
ditions are satised. The incident wave vector (a vector which helps describe
a wave and whose direction is the direction of wave propagation) is given by
the equation (ICX Nomadics: Overview of surface plasmon resonance)
k
i i
=
⎛
⎝
⎜
⎞
⎠
⎟
2π
λ
μ θsin
(2.2)
where
k
i
is a component of ...