Biomedical Engineering Reference
In-Depth Information
Figure 4.18
Thedependenceoftheradiativedecayrateofthespontaneous
emission of the “right” (
m
0
=+
0.1
d
0
)and“left”(
m
0
=−
0.1
d
0
)chiral
molecules on the real part of permittivity (
ε
=
ε
+
i
0.1) at
μ
=−
1.6,
k
0
a
0.2. (a) The molecule is placed in close vicinity to the
surface of a single sphere (
r
0
→
=
0.1, and
χ
=
a
). (b) The molecule is placed in the gap
of the two-sphere cluster in close vicinity to the surface of the first sphere
(
1
r
0
→
a
,
2
r
0
=
−
l
a
). The relative distance between the particles centers
/
=
is
l
(2
a
)
1.1. The particles are placed in vacuum.
the chiral nanoantenna has substantially greater values than in the
case of chiral molecule near a singlechiral nanoparticle.
In Fig. 4.19, the ratio of the radiative decay rate of spontaneous
emission of the “left” molecule and the radiative decay rate of the
“right” molecule (
γ
rad
/γ
L
rad
), and vice versa (
γ
R
rad
/γ
R
L
rad
), is shown as
functions of the permittivity and permeability of the chiral cluster.
The molecule is located in the gap between the particles near the
surface ofthe first spherical particles ofthe cluster.
From this figure, it follows that for certain values
ε
and
μ
,there
is a very significant difference in the radiative decay rates of the
“right” and “left” molecules in 40 or even in 300 (and more) times,
which can exceed significantly the analogous results for a single
chiral nanoparticle (cf. Fig. 4.14 and Fig. 4.19).
AsitisseeninFig.4.19,aswellasforasinglechiralnanoparticle,
a chiral nanoantenna with
ε<
0and
μ<
0 (DNG-metamaterial)
willenhancetheradiationofthe“left”moleculesandslowdownthe
radiation of the “right” molecules, while the cluster with
ε>
0and
μ<
0 (MNG-metamaterial) will enhance the radiation of the “right”
molecules and suppress the radiation of the “left” molecules.
