Browsing by Author "Aydın, Koray"
Now showing items 1-19 of 19
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Characterization and applications of negative-index metamaterials
Aydın, Koray (Bilkent University, 2008)Metamaterials offer novel electromagnetic properties and promising applications including negative refraction, flat-lenses, superlenses, cloaking devices. In this thesis, we characterized the negative-index metamaterials ... -
Exceptional adaptable MWIR thermal emission for ordinary objects covered with thin VO2 film
Durna, Yılmaz; Kocer, Hasan; Aydın, Koray; Cakir, Mehmet Cihan; Soydan, Mahmut Can; Odabasi, Oguz; Işık, Halil; Ozbay, Ekmel (Elsevier Ltd, 2021-01-25)Monotonous thermal radiation emitted from an ordinary object can be brought into a dynamic and versatile form that can be shaped according to the application area with the ingenious design of the surface coatings. Building ... -
Experimental analysis of true left-handed behaviour and transmission properties of composite metamaterials
Güven, Kaan; Aydın, Koray; Özbay, Ekmel (Elsevier, 2005-12)We report the true left-handed transmission of a composite metamaterial (CMM) consisting of periodically stacked split-ring resonator (SRR) and wire elements. The negative permeability (μ < 0) gap is demonstrated explicitly ... -
Experimental demonstration of negative refraction and subwavelength imaging by left-handed composite metamaterials
Özbay, Ekmel; Aydın, Koray; Özkan, Gonca; Bulu, İrfan (Cambridge University Press, 2006)We report a true left-handed (LH) behavior and focusing in a composite metamaterial consisting of periodically arranged split ring resonator (SRR) and wire structures. The magnetic resonance of the SRR structure is ... -
Experimental observation of true left-handed metamaterial
Aydın, Koray; Güven, Kaan; Özbay, Ekmel (IEEE, 2005)We report a true left-handed (LH) behavior in composite metamaterials. The magnetic resonance of the SRR structure is demonstrated. Plasma frequency of the LH material is shown to be lower than that of the wires. -
Ferroelectric based tuneable SRR based metamaterial for microwave applications
Özbay, Ekmel; Aydın, Koray; Bütün, Serkan; Kolodziejak, K.; Pawlak, D. (IEEE, 2007)We discuss the possibility of achieving tunable split ring resonators at microwave frequencies. One method is to use varying capacitance values to tune the magnetic resonance frequency. As another method ferroelectric thin ... -
Microwave transmission through metamaterials in free space
Aydın, Koray; Bayındır, Mehmet; Özbay, Ekmel (2002)To investigate properties of metamaterials, composite structures which consists of periodical arrangement of thin copper wires and SRRs on a circuit board was constructed. Through this, the transmission properties of ... -
Negative phase advance in polarization independent, multi-layer negative-index metamaterials
Aydın, Koray; Zhaofeng, Li; Şahin, Levent; Özbay, Ekmel (Optical Society of American (OSA), 2008)We demonstrate a polarization independent negative-index metamaterial (NIM) at microwave frequencies. Transmission measurements and simulations predict a left-handed transmission band with negative permittivity and negative ... -
Negative refraction and focusing by a left-handed material slab in free space
Aydın, Koray; Özbay, Ekmel (IEEE, 2006)Negative refraction and focusing by a left-handed metamaterial (LHM) slab are experimentally verified. We measured refractive index of slab as -1.86. The flat lens behavior of LHM is demonstrated for two different point ... -
Negative refraction and subwavelength focusing using left-handed composite metamaterials
Özbay, Ekmel; Aydın, Koray (SPIE, 2008-01)We review experimental studies performed on left-handed metamaterials (LHM) at microwave frequencies. The metamaterial structure is composed of periodic arrays of split-ring resonators and wire meshes and exhibits a ... -
Negative refraction and subwavelength focusing using photonic crystals
Özbay, Ekmel; Aydın, Koray; Alıcı, Kamil Boratay; Güven, Kaan (SPIE, 2005-01)We review certain novel optical properties of two-dimensional dielectric photonic crystals (PCs) which exhibit negative refraction behavior. We investigate two mechanisms which utilize the band structure of the PC and lead ... -
Negative refraction using true left-handed metamaterials
Aydın, Koray (Bilkent University, 2004)Left-handed materials and negative refraction attracted a great amount of attention in recent years due to their unique physical properties. It is possible to obtain a left-handed material by combining a novel artificial ... -
Physics and applications of photonic nanocrystals
Özbay, Ekmel; Güven, Kaan; Aydın, Koray; Bayındır, Mehmet (Inderscience Publishers, 2004)Photonic nanocrystals are periodic dielectric or metallic structures having photonic bands in analogy to electronic bands of semiconductors. The presence of photonic band-gaps, where the propagation of photons of certain ... -
Review of experimental studies on microwave left-handed metamaterials
Özbay, Ekmel; Aydın, Koray (American Institute of Physics, 2007)We review experimental studies on left-handed metamaterials operating at microwave frequencies. Left-handed transmission is obtained from a composite metamaterial consisting of periodic split ring resonator and wire arrays. ... -
Spectral negative refraction and focusing analysis of a two-dimensional left-handed photonic crystal lens
Güven, Kaan; Aydın, Koray; Alıcı, Kamil Boratay; Soukoulis, C. M.; Özbay, Ekmel (American Physical Society, 2004-11)We report the spectral refraction analysis and focusing properties of a two-dimensional, dielectric photonic crystal (PC) slab in freespace. A transverse electric polarized upper band of the crystal is used. The measured ... -
Transmission and reflection properties of composite metamaterials in free space
Aydın, Koray; Çubukcu, Ertuğrul; Özbay, Ekmel; Bayındır, Mehmet (OSA, 2003)We measured transmission and reflection from SRRs, thin wires, and composite metamaterials in free space. X-band measurement exhibits high transmission magnitude for frequencies where both SRR and wire have effective ... -
Transmission properties of various split-ring resonator systems
Aydın, Koray; Bulu I.; Güven, K.; Özbay, Ekmel (Optical Society of America, 2006)We investigated the magnetic resonance of split-ring resonators (SRR) experimentally. The dependence of the geometrical parameters on the resonance frequency of SRR is studied. We further investigated the effect of disorder ... -
Two-dimensional left-handed metamaterial with a negative refractive index
Aydın, Koray; Güven, Kaan; Özbay, Ekmel (IOP, 2006)We present a two-dimensional metamaterial with left-handed properties in a certain frequency range where both effective dielectric permittivity and magnetic permeability is simultaneously negative. A wedge-shaped metamaterial ... -
Verification of impedance matching at the surface of left-handed materials
Aydın, Koray; Bulu, İrfan; Özbay, Ekmel (Wiley, 2006)Impedance matching at the surface of left-handed materials (LHM) is required for certain applications including a perfect lens. In this study, we present the experimental and theoretical verification of an impedance-matched ...