Biomedical Engineering Reference
In-Depth Information
Figure 4.12
Radiative decay rate of the spontaneous emission of a chiral
molecule located in close vicinity to the surface of a chiral dielectric
spherical particle (
r
0
→
a
) with
ε
=
6and
μ
=
1 as a function of its size,
k
0
a
. (a) The transition electric dipole moment of the molecule is oriented
tangentially to the surface of the particle. (b) The transition electric dipole
moment of the molecule is normal to the surface of the particle. The solid
line corresponds to the transition magnetic dipole moment of a molecule
orientedalongthesurface(
m
0
x
=
0.1
d
0
),whilethedashedlinecorresponds
to the transition magnetic dipole moment of a molecule oriented normally
to the sphere surface (
m
0
z
=
0.1
d
0
). The particle is placed in vacuum.
to smaller resonant values of
k
0
a
than those of a nonchiral particle.
Even more interesting feature of ordinary dielectric particles with
a small admixture of chirality is a substantial increase in the quality
factorofwhisperinggallerymodes.Thisfigureclearlyshowsthatthe
corresponding linewidth can beincreased by factor 9or even more.
Note also that in Fig. 4.12 only a slight difference between the
radiative decay rates of spontaneous emission corresponding to the
different orientations of the transition magnetic dipole moment of
a chiral molecule at a fixed electric dipole moment is observed.
However,oneshouldexpectanincreaseofthisdifferenceinthecase
of increasing of absolutevalues of the magnetic dipole momentum.
Figure 4.13 shows the radiative decay rate of spontaneous emis-
sion of a chiral molecule located near chiral spherical nanoparticles
as a function of the chirality
χ
. As it is clearly seen in this figure,
changing the chirality of the sphere has the greatest impact on
the rate of spontaneous decay of the molecules near a dielectric
and left-handed spherical particles, in which high-
Q
modes can
be excited. When
the
chirality parameter approaches a critical
value
/
√
εμ
χ
crit
=
1
, the number of oscillations in the radiative
