ELECTRICAL AND ELECTRONICS ENGINEERING


Kadir Üstün

Picture of the person
Room No: 
D-223
Tel No: 
+90 (312) 210-4417
E-mail: 
ukadir metu edu tr
Education: 

PhD candidate @ METU EE since 09/2011 Master of Science: TOBB University of Economics and Technology 09/2011 Bachelor: METU EE 06/2008

Research Interests: 

Metamaterials, Photonic Crystals

Publications: 

· Khalil Dadashi, Hamza Kurt, Kadir Üstün, and Ramazan Esen, "Graded index optical microresonators: analytical and numerical analyses," J. Opt. Soc. Am. B 31, 2239-2245 (2014) http://www.opticsinfobase.org/josab/abstract.cfm?URI=josab-31-9-2239 · Kadir Üstün and Hamza Kurt, "Efficient and broadband guided wave one-way mode-order conversion with theoretical and numerical analysis," J. Opt. Soc. Am. B 30, 2992-2998 (2013) http://www.opticsinfobase.org/josab/abstract.cfm?URI=josab-30-11-2992 · Kadir Üstün and Hamza Kurt, "Slow light structure with enhanced delay–bandwidth product," J. Opt. Soc. Am. B 29, 2403-2409 (2012). http://www.opticsinfobase.org/josab/abstract.cfm?URI=josab-29-9-2403 · Hamza Kurt, Nur Erim, and Kadir Üstün, "Slow light based on optical surface modes of two-dimensional photonic crystals," J. Opt. Soc. Am. B 29, 1187-1193 (2012). http://www.opticsinfobase.org/josab/abstract.cfm?URI=josab-29-6-1187 · Kadir Üstün and Hamza Kurt, "Compact coupling of light from conventional photonic wire to slow light waveguides", Journal of Applied Physics, vol. 110, pp. 113109 (1-7) (2011). http://jap.aip.org/resource/1/japiau/v110/i11/p113109_s1?isAuthorized=no · Hamza Kurt, İbrahim H. Giden, and Kadir Üstün, "Highly efficient and broadband light transmission in 90° nanophotonic wire waveguide bends," J. Opt. Soc. Am. B vol. 28, 495-501 (2011) http://www.opticsinfobase.org/josab/abstract.cfm?URI=josab-28-3-495. · Hamza Kurt, Kadir Üstün, and Lokman Ayas, "Study of different spectral regions and delay bandwidth relation in slow light photonic crystal waveguides," Optics Express vol. 18, 26965-26977 (2010) http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-18-26-26965. · Kadir Üstün and Hamza Kurt, "Ultra slow light achievement in photonic crystals by merging coupled cavities with waveguides," Optics Express vol. 18, 21155-21161 (2010). http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-18-20-21155

Thesis / Research Information: 

ELECTRICAL, OPTICAL AND MECHANICAL TUNING OF METAMATERIALS IN INFRARED AND TERAHERTZ REGIME Metamaterials are artificial materials designed as periodic arrays of sub-wavelength resonators. Around the resonance wavelength, real parts of effective permittivity and/or effective permeability of metamaterials can attain near zero or negative values. The case of metamaterials with negative refractive index attracts special attention because of potential applications such as sub-diffraction imaging and cloaking. However, an important drawback of these engineered materials is their narrow-band spectral behavior calling for the need to design structures with adjustable resonance frequencies by including tunable features into the metamaterial design. Accordingly, the aim of this thesis is to devise novel methods of tuning the resonance frequency of metamaterials within a wide frequency window in Terahertz and Infrared regimes. One of the tuning mechanisms would be changing the geometry or period of the resonating unit cells with application of stress-strain onto the material. Another tuning mechanism is to change the electrical properties of the material, which is embedded in the resonating structures, using some sort of external stimuli.