Physics PhD Thesis Defense by Aybike Ural Yalçın

KOÇ UNIVERSITY

GRADUATE SCHOOL OF SCIENCES & ENGINEERING

PHYSICS

PhD THESIS DEFENSE BY AYBİKE URAL YALÇIN

Title:Chiral resonators: Selected electromagnetic and optomechanic applications in microwave and plasmonics

Speaker:Aybike Ural Yalçın

Time:January 29, 2018, 10:00

Place: SCI-103

Koç University

Rumeli Feneri Yolu

Sariyer, Istanbul

Thesis Committee Members:

Assoc.Prof. Kaan Güven (Advisor, Koc University)

Prof. Ali Serpengüzel (Koc University)

Prof. İrşadi Aksun (Koc University)

Assoc.Prof. Hakan Özgür Özer (Istanbul Technical University)

Assoc.Prof.Ahmet Levent Subaşı (Istanbul Technical University)

Abstract:

This thesis work comprises the investigation of metal canonical spirals as chiral resonators at two different parts of the electromagnetic spectrum (namely microwave C-band and optical/near infrared bands) and aims to exemplify their functionalization for microwave transmission and optical force generation, respectively.

The first part encapsulates the systematic analysis of the electromagnetic response of canonical spirals in the microwave regime. In this context, 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 the 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. One-dimensional periodic arrays of canonical spirals with same or alternating handedness within a waveguide are constructed, that give rise to chirality-dependent band gaps within the transmission band of the fundamental mode of the waveguide.

The second part investigates the optomechanical effects of canonical spiral chiral plasmonic resonators which can be utilized for chirality selective optical trapping and binding functionalities. The radiation pressure exerted by the plane-wave is even stronger due to the excitation of the plasmonic resonances of the nanoparticle. In coupled configurations, other optical force components come into play by the field created from coupled chiral structures. Furthermore, the effect of the substrate under the canonical spirals is discussed.