Light matter interaction in plexcitonic crystals and moiré cavities
Author
Karademir, Ertuğrul
Advisor
Aydınlı, Atilla
Date
2015-01Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
102
views
views
241
downloads
downloads
Abstract
Surface plasmon polaritons (SPPs) are quanta of electromagnetic excitations at
the interface between metal and dielectric media. SPPs with an evanescent tail
in the perpendicular direction, thus their properties are sensitive to variations
in the optical properties of the dielectrics film. If SPPs are created near excitonic
media, coupling between excitons and SPs can be achieved. In this thesis,
interaction dynamics of SPP-exciton coupling is investigated. In weak coupling
case, properties of SPPs and excitons are perturbed as the enhancement of the
optical absorption in excitonic matrices. In the strong coupling, coupled pairs
(plexcitons) causes Rabi splitting in SPP dispersion curves. By patterning the
metal-dielectric interface with sine profile grating, it is possible to form a band
gap on the dispersion curve, width of which can be tuned by the groove depth
and SPP-Exciton coupling can be engineered. Using this, a new type of crystal,
plexcitonic crystal, is proposed and demonstrated that exhibit directional
dependent coupling on square and triangular lattices. Superposing an additional
grating on the initial one but with a slight difference in pitch, results in Moir e
cavities, in which, slow plasmon modes can be confined. We show that we can
directly image these modes using dark field microscopy. Further, the slow cavity
mode in contact with an excitonic source, where SPPs are coupled with near
field coupling, results in ampliffed light signal. Various Moire cavities are shown
to exhibit plasmonic lasing when slow plasmon modes in Ag coated cavities are
excited inside a suitable gain medium.
Keywords
Surface plasmon polaritonsExcitons
Light matter interaction
Plexcitonic crystals
Moire cavities
Plasmonic lasers