Kiral rezonatörler: Mikrodalga ve plazmonik dalgaboylarında seçilmiş elektromanyetik ve optomekanik uygulamalar

This thesis investigates selected electromagnetic and optomechanic properties of chiral resonator structures in the microwave and plasmonic (optic) regime, respectively. The first part of the thesis focuses on the systematic study of the electromagnetic response of canonical spiral shaped chiral resonators in the microwave regime. Canonical spiral provides a chiral extension of the split ring resonator which is a well-known building element of the electromagnetic metamaterials. Various configurations of single and coupled chiral resonators are studied experimentally and computationally. In particular, the role of chirality in coupled configurations consisting of same-handed and opposite handed (enantiomeric) canonical spirals is investigated. Within a waveguide one-dimensional periodic arrays of canonical spirals with same or alternating handedness, that give rise to chirality-dependent band gaps within the transmission band of the fundamental mode of the waveguide are constructed. Based on a good agreement between experiments and simulations the following results are prominent: (i) optimal canonical spirals are fabricated which exhibit both electric and magnetic dipole excitation at the same resonance frequency. (ii) resonance splitting of coupled spirals show that the lower (higher) mode is stronger for spiral pairs of same (opposite) handedness. (iii) chains of spiral pairs exhibit chirality selective stop bands respectively at the lower and upper frequency modes of an individual spiral pair. A chain with uniform helicity opens a gap at the high frequency mode whereas a chain consisting of enantiomer pairs opens a gap at the lower frequency mode. The second study involves the optomechanical effects of canonical spiral chiral plasmonic resonators which can be utilized for chirality selective optical trapping and binding functionalities. The spectra of the optical force components that act on a single or coupled spiral system under plane-wave excitation are computed. We then repeat the calculations in the presence of a planar metal surface in the vicinity of the spirals. This study is based on a theoretical and computational (simulation-based) framework. The major outcomes of this part are that for spiral pair the relative lateral force perpendicular to the incident polarization direction are chirality dependent. The same handed spiral pair tends to bind by an attractive force, whereas the opposite handed pair repel each other. The optical force acting in the direction of the light propagation on the single or coupled spiral pair is independent of the chirality. The presence of the metal substrate generates a strong attractive force towards the metal surface on the spiral resonators.