Biomedical Engineering Reference
In-Depth Information
Figure 4.19
(a) The ratio of the radiative decay rate of spontaneous
emission of the “left” (
m
0
=−
0.1
d
0
) chiral molecule and the radiative
decay rate of spontaneous emission of the “right” (
m
0
=+
0.1
d
0
)chiral
molecule,and(b)viceversa,asafunctionoftherealpartofthepermittivity
(
ε
=
ε
+
μ
=
μ
+
i
0.1) and the real part of the permeability (
i
0.1) of the
=
χ
=
material of cluster of two chiral nanoparticles with
k
0
a
0.2.
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
0.1 and
→
a
,
2
r
0
=
−
a
) in the common
z-axis. The relative distance between the particles centers is
l
l
/
=
(2
a
)
1.1.
The particles are placed in vacuum.
The significant difference between the radiative decay rates of
“right” and “left” enantiomers of molecules located near a cluster
of two chiral nanoparticles made of metamaterials allows using
such clusters for creation of effective devices for detection and
selectionofenantiomers.Notethatduetoincreaseoflocalmagnetic
fields, the effect of discrimination for a chiral nanoantenna is much
greater than for a single chiral nanoparticle. Possible variants of the
application of these effects are discussed in the followingsection.
4.5 Applications
The predicted effect of influence of chiral nanoparticles on the
radiation of optically active molecules can be used in many
applications[42].Here,wementiononlytwo,themostobviousones.
The first application is the observation of “right” or “left” molecules
separately witha scanning microscope (see Fig. 4.20).
To do so, specially prepared nanoparticles [see (4.50)] are
attached to the tip of a scanning microscope to increase the
