Biomedical Engineering Reference
In-Depth Information
Figure 9.5
Scatteringe
ciencies
Q
FS
and
Q
BS
fortheparticlewith
q
=
0.02
versus
ε
. Insets show the far-field scattering diagrams at the corresponding
frequencies, calculated with Eq. (9.8) at the corresponding frequencies:
ε
1
10
−
5
corresponds to zero forward
=−
1.5
−
δ
1
,where
δ
1
=
1.67
·
10
−
5
corresponds to zero
scattering,
ε
2
=−
1.5
+
δ
2
where
δ
2
=
1.67
·
backward scattering.
9.4 Formation of Vortices within the Mie Theory
Another type of interference phenomena is related to topological
optics, and it is associated with terms such as singular optics,
vortices, and dislocations of the wave front [12-15]. The basic point
of the topological optics is an undefined phase of electromagnetic
field at the points where the intensity of the wave vanishes. Any
2
π
n
phase values can be continuously conjugated at this point.
The integer
n
presents the so-called topological charge, which
shows the number of twists that light does in one wavelength.
There are many methods to create optical vortices by diffraction,
computer-generated holograms, and a special light modulator.
Recently, it was shown that the vortices can be created during
