Researcher:
Kocabaş, Şükrü Ekin

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Şükrü Ekin

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Kocabaş

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Kocabaş, Şükrü Ekin

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2012 - 20189

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Researcher Of Publications: search.filters.isAuthorOfPublication.144efb00-b6ba-490b-b7c2-6fd2d421f170

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Now showing 1 - 9 of 9
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    Resonance fluorescence in a waveguide geometry
    (IEEE, 2012) Rephaeli, Eden; Fan, Shanhui; Department of Electrical and Electronics Engineering; Kocabaş, Şükrü Ekin; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; N/A
    We show how to calculate the first-and second-order statistics of the scattered fields for an arbitrary intensity coherent-state light field interacting with a two-level system in a waveguide geometry. Specifically, we calculate the resonance fluorescence from the qubit, using input-output formalism. We derive the transmission and reflection coefficients, and illustrate the bunching and antibunching of light that is scattered in the forward and backward directions, respectively. Our results agree with previous calculations on one-and two-photon scattering as well as those that are based on the master equation approach.
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    Experimental investigation of stub resonators built in plasmonic slot waveguides
    (Ieee-Inst Electrical Electronics Engineers Inc, 2017) Karasahin, Aziz; N/A; N/A; Department of Electrical and Electronics Engineering; N/A; Naghizadeh, Solmaz; Kocabaş, Şükrü Ekin; Arısev, Ongun; PhD Student; PhD Student; Faculty Member; Master Student; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; Graduate School of Sciences and Engineering; N/A; N/A; N/A; N/A
    In this letter, we focus on stub resonators embedded in plasmonic slot waveguides. The resonators have potential applications in optical interconnects and sensors. We fabricate the samples by electron beam lithography and lift-off. We use a scattering matrix-based model to quantify the optical power output from the samples. We measure the properties of the resonators by coupling light in and out of the slot waveguides by optical antennas, making use of a cross-polarization-based setup utilizing a supercontinuum source and a high numerical aperture objective lens operating in the telecom-wavelength range. Our model agrees well with the measured data. Furthermore, development on the stub resonators can be made by using the methods in this letter.
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    Few photon - qubit scattering in dispersive waveguides
    (Institute of Electrical and Electronics Engineers (IEEE), 2016) N/A; Department of Electrical and Electronics Engineering; Kocabaş, Şükrü Ekin; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; N/A
    Dispersion in waveguides leads to atom-photon bound states in qubits embedded in waveguides. We utilize Feynman diagrams and numerical simulations to analyze one-and two-photon scattering from qubits with the aim to test different quantum information processing schemes.
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    Few-photon scattering in dispersive waveguides with multiple qubits
    (Optical Soc Amer, 2016) N/A; Department of Electrical and Electronics Engineering; Kocabaş, Şükrü Ekin; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; N/A
    We extend the Krylov-subspace-based time-dependent numerical simulation technique for a qubit interacting with photons in a waveguide to the multiple qubit case. We analyze photon scattering from two qubits and derive expressions for the bound states in the continuum (BICs). We show how the BIC can be excited. We use the BIC in a recent Pauli-Z gate proposal involving decoherence free subspaces and obtain the gate fidelity as a function of the gate parameters. The techniques presented in this Letter are useful for investigating the time evolution of quantum gates and other many-body systems with multiple quenches in the Hamiltonian.
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    The effect of metal thickness on si wire to plasmonic slot waveguide mode conversion
    (Süleyman Demirel Üniversitesi, 2018) N/A; Department of Electrical and Electronics Engineering; Kocabaş, Şükrü Ekin; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; N/A
    We investigate mode converters for Si wire to plasmonic slot waveguides at 1550 nm telecom wavelength. The structures are based on a taper geometry. We provide optimal dimensions with more than 90% power transmission for a range of metal (Au) thicknesses between 30-250 nm. We provide details on how to differentiate between the total power and the power in the main mode of the plasmonic slot waveguide. Our analysis is based on the orthogonality of modes of the slot waveguide subject to a suitable inner product definition. Our results are relevant for lowering the insertion loss and the bit error rate of plasmonic modulators. / Bu çalı¸smada 1550 nm telekom dalga boyunda çalı¸san, Si tel dalga kılavuzundan plazmonik yiv dalga kılavuzuna kip dönü¸stürücülerini inceledik. Söz konusu yapılar gittikçe incelen bir geometriye sahiptir. 30-250 nm arasındaki metal (Au) kalınlıkları için %90’dan yüksek güç iletimine sahip en uygun boyutları sunduk. Plazmonik yiv dalga kılavuzuna e¸slenen güç ile iletilen toplam gücün nasıl birbirinden ayrılabilecegini ˘ ayrıntılarıyla açıkladık. ˙Incelememiz yiv dalga kılavuzu kiplerinin uygun bir iç çarpım tanımı sonucu birbirlerine dikgen olmasına dayanmaktadır. Sonuçlarımız plazmonik modülatörlerin baglanma kaybı ve bit hata oranlarının azaltılmasına katkı sunacaktır.
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    Beam steering and impedance matching of plasmonic horn nanoantennas
    (Optical Soc Amer, 2016) N/A; Department of Electrical and Electronics Engineering; Afridi, Adeel; Kocabaş, Şükrü Ekin; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A
    In this paper, we study a plasmonic horn nanoantenna on a metal-backed substrate. The horn nanoantenna structure consists of a two-wire transmission line (TWTL) flared at the end. We analyze the effect of the substrate thickness on the nanoantenna's radiation pattern, and demonstrate beam steering in a broad range of elevation angles. Furthermore, we analyze the effect of the ground plane on the impedance matching between the antenna and the TWTL, and observe that the ground plane increases the back reflection into the waveguide. To reduce the reflection, we develop a transmission line model to design an impedance matching section which leads to 99.75% power transmission to the nanoantenna. (C) 2016 Optical Society of America.
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    Guidelines for designing 2D and 3D plasmonic stub resonators
    (Optical Soc Amer, 2017) N/A; N/A; Department of Electrical and Electronics Engineering; Naghizadeh, Solmaz; Kocabaş, Şükrü Ekin; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A
    In this work, we compare the performance of plasmonic waveguide integrated stub resonators based on 2D metal-dielectric-metal and 3D slot waveguide (SWG) geometries. We show that scattering matrix theory can be extended to 3D devices, and by employing scattering matrix theory, we provide the guidelines for designing plasmonic 2D and 3D single-stub and double-stub resonators with a desired spectral response at the design wavelength. We provide transmission maps of 2D and 3D double-stub resonators versus stub lengths, and we specify the different regions on these maps that result in a minimum, a maximum, or a plasmonically induced transparency shape in the transmission spectrum. Radiation loss from waveguide terminations leads to a degradation of the 3D SWG-based resonators. We illustrate improved waveguide terminations that boost resonator properties. We verify our results with 3D finite-difference time-domain (FDTD) simulations.
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    PublicationOpen Access
    Effects of modal dispersion on few-photon-qubit scattering in one-dimensional waveguides
    (American Physical Society (APS), 2016) Department of Electrical and Electronics Engineering; Kocabaş, Şükrü Ekin; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering
    We study one- and two-photon scattering from a qubit embedded in a one-dimensional waveguide in the presence of modal dispersion. We use a resolvent based analysis and utilize techniques borrowed from the Lee model studies. Modal dispersion leads to atom-photon bound states which necessitate the use of multichannel scattering theory. We present multichannel scattering matrix elements in terms of the solution of a Fredholm integral equation of the second kind. Through the use of the Lippmann-Schwinger equation, we derive an infinite series of Feynman diagrams that represent the solution to the integral equation. We use the Feynman diagrams as vertex correction terms to come up with closed-form formulas that successfully predict the trapping rate of a photon in the atom-photon bound state. We verify our formalism through Krylov-subspace based numerical studies with pulsed excitations. Our results provide the tools to calculate the complex correlations between scattered photons in a dispersive environment.
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    PublicationOpen Access
    Resonance fluorescence in a waveguide geometry
    (American Physical Society (APS), 2012) Rephaeli, Eden; Fan, Shanhui; Department of Electrical and Electronics Engineering; Kocabaş, Şükrü Ekin; PhD Student; Department of Electrical and Electronics Engineering; College of Engineering
    We show how to calculate the first-and second-order statistics of the scattered fields for an arbitrary intensity coherent-state light field interacting with a two-level system in a waveguide geometry. Specifically, we calculate the resonance fluorescence from the qubit, using input-output formalism. We derive the transmission and reflection coefficients, and illustrate the bunching and antibunching of light that is scattered in the forward and backward directions, respectively. Our results agree with previous calculations on one-and two-photon scattering as well as those that are based on the master equation approach.