Radiation properties of sources inside photonic crystals
Author
Bulu, İrfan
Advisor
Özbay, Ekmel
Date
2003Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Abstract
The control of spontaneous emission is an important problem both in basic
and applied physics. Two main problems arise in the control of emission: enhancement
or suppression and angular confinement of radiation. In this work we
studied the properties of emission of radiation from a localized microwave source
embedded inside a photonic crystal. We showed that by using a photonic crystal
it is possible to enhance the emitted power. We achieved up to 22 times enhancement
of power at the band edge of the photonic crystal. We also studied the
properties of emission of radiation from a source embedded inside a single defect
structure and embedded inside a coupled defect structure. Enhanced emission
for single defect and coupled defect structures was also observed. Moreover, angular
distribution of power from a localized microwave source embedded inside a
photonic crystal was studied. Angular confinement was achieved near the band
edge of the photonic crystal. Half power beam widths as small as 6 degrees were
obtained. This is the smallest half power beam width in the literature obtained
by using photonic crystals. We also investigated frequency and size dependence
of the angular distribution. We observed that the angular confinement strongly
depends on frequency and on the size of the photonic crystal. In fact, we showed
that angular confinement could be obtained just at the band edge frequency. In
conclusion, our work showed that the problem of controlling the spontaneous
emission could be solved at once by using photonic crystals.
Keywords
photonic crystalangular confinement
group velocity
dipole
spontaneous emission
enhanced radiation
FDTD
band structure
radiation