Ergun Simsek
Ergun Simsek, Ph.D.
Manager
Electrical Engineering & Computer Science
Bowie

Dr. Simsek has over 15 years of research, development, and teaching experience in electromagnetics and optics. He leverages his broad experience and educational background to solve a wide variety of problems in consumer electronics, appliances, vehicles, military and medical devices, data science, and manufacturing. He has experience in design, development and manufacturing processes, failure analysis, microelectronic and photonic circuits, and passive components.

Dr. Simsek’s expertise in electromagnetics includes development of finite-difference time-domain and frequency domain (method of moments, spectral integral method, finite-element method) solvers tailored for specific applications; design and characterization of passive and active RF/microwave devices using his own algorithms as well as commercial software packages such as Wavenology, Ansoft HFSS, FEKO, and Lumerical; electromagnetic compatibility and interference analysis; electromagnetic inversion; and realistic modeling of power systems.

In optics, Dr. Simsek has conducted theoretical, computational, and experimental studies on plasmonic and photonic devices deploying periodic metal nano-structures, quantum dots, nano-wires, and atomically thin layered materials (i.e. graphene and transition-metal dichalcogenides). He is versed in all the major optical characterization techniques and equipment and nanofabrication methods.

Dr. Simsek has a successful record of utilizing his expertise in other areas of science and engineering such as quantum dynamics, geophysics, and data science. He proposed novel mathematical frameworks to investigate exciton dynamics in thin semi-conducting films, luminescence mechanisms, and laser ablation. From borehole seismic downhole array tool design to seismic interpretation, structural and fault analysis to signal processing, Dr. Simsek is highly knowledgeable about borehole geophysics. Dr. Simsek is competent in number of computer programming languages (C, C++, FORTRAN, and Java), scripting languages (R and Python), and engineering platforms (Matlab, Octave, Mathematica) and he is skilled at using this knowledge and experience in data science for regression, classification, and unsupervised learning.

Dr. Simsek received his Ph.D. in Electrical Engineering from Duke University. His doctoral work centered on the development of efficient and robust algorithms revealing the interaction of electromagnetic waves with objects embedded in multilayered media. The results of this research have been utilized in various fields from underground object detection to plasmonic laser design. During his post-doctoral work at the Schlumberger Doll Research Center, he was a member of the team who carried in-depth analysis of future drilling devices and provided feedback for performance improvement. He performed advanced studies on the influence of borehole shape, deviation, pressure, and anisotropy on the slowness dispersions of the borehole modes. As a Marie Curie fellow and an academic, Dr. Simsek conducted research on nano-optics. His experience includes design, fabrication, and characterization of surface plasmon resonance sensors, electro-optic modulators, and highly efficient polarization-independent absorbers; characterization of atomically thin layered materials through spectroscopy, and development of wavelength, temperature, and Fermi energy dependent complex electrical permittivity models for such thin films. During his fellowship at the Naval Research Laboratory, he collaborated with quantum chemists on dark states to be used for exciton storage in transition-metal dichalcogenides. 

Dr. Simsek has published 30 peer-reviewed research articles in top international journals and made more than 60 presentations at major international conferences. He taught several electrical engineering courses on electromagnetics, optics, microwave engineering, antennas, and scientific computing at both undergraduate and graduate levels.

CREDENTIALS & PROFESSIONAL HONORS

  • Ph.D., Electrical and Computer Engineering, Duke University, 2006
  • M.S., Electrical Engineering, University of Massachusetts, Dartmouth, 2003
  • B.S., Electrical and Electronics Engineering, Bilkent University, 2001

Publications

Mukherjee B, Kaushik N, Tripathi RP, Joseph AM, Mohapatra PK, Dhar S, Pavan Kumar GV, Simsek E, Lodha S. Exciton Emission Intensity Modulation of Monolayer MoS2 via Au Plasmon Coupling. Scientific Reports 2017:41175.

Mukherjee B, Varghese B, Zheng M, Tok ES, Simsek E, Sow CH. Photoconductivity in VO2-ZnO Inter-nanowire Junction and Nanonetwork Device. Nanoscience and Nanotechnology Letters 2016; 8:492-497.

Simsek E, Mukherjee B. Utilization of monolayer MoS2 in Bragg Stacks and Metamaterial Structures as Broadband Absorbers. Optics Communications 2016; 369:89-93.

Mukherjee B, Simsek E. Plasmonics Enhanced Average Broadband Absorption of Monolayer MoS2. Plasmonics 2016; 11(1): 285-289.

Tseng F, Simsek E, Gunlycke D. Using Dark States for Exciton Storage in Transition-Metal Dichalcogenides. Journal of Physics: Condensed Matter. 2016; 28(3): 034005.

Mukherjee B, Simsek E. Visibility of Atomically Thin Layered Materials Buried in Silicon Dioxide. IOP Nanotechnology 2015; 26(45): 455701. 

Mukherjee B, Leong WS, Li Y, Gong H, Sun L, Shen Z, Simsek E, Thong J. Raman analysis of gold on WSe2 single crystal film. Material Research Express 2015; 2:065009. 

Mukherjee B, Tseng F, Gunlcyke D, Kumar Amara K, Eda G, Simsek E. Complex Electrical Permittivity of the Monolayer Molybdenum Disulfide (MoS2) in Near UV and Visible. Optical Material Express 2015; 5(2): 447-455. 

Sahin R, Akturk S, Simsek E. Quantifying the Quality of Femtosecond Laser Ablation of Graphene. Applied Physics A 2014; 116(2): 555-560. 

Sahin R, Simsek E, Akturk S. Nanoscale Patterning of Graphene through Femtosecond Laser Ablation. Applied Physics Letters 2014; 104: 053118. 

Ye C, Sikandar K, Li Z, Simsek E, Sorger VJ. Wavelength-Size ITO and Graphene-based Electro-optic Modulators on SOI. IEEE Journal of Selected Topics in Quantum Electronics 2014; 20(4): 40-49.

Simsek E, Graphene in Layered Medium Applications. Microwave and Optical Technology Letters 2013; 55(10): 2293-2296.

Sahin R, Morova Y, Simsek E, Akturk S. Bessel-Beam-Written Nanoslit Arrays and Characterization of their Optical Response. Applied Physics Letters 2013; 102 (19): 193106. 

Simsek E. A Closed-Form Approximate Expression for the Optical Conductivity of Graphene. Optics Letters 2013; 38(9): 1437-1439. 

Simsek E. Improving the Tuning Range and Sensitivity of Localized Surface Plasmon Resonance Sensors with Graphene. IEEE Photonics Technology Letters 2013; 25(9): 867-870. 

Simsek E, Akturk S. Plasmonic Enhancement during Femtosecond Laser Drilling of sub-Wavelength Holes in Metals. Plasmonics 2011; 6(4): 767-772.

Simsek E. Full Analytical Model for Surface Plasmon Coupling in Periodic Metallic Nanoparticle Structures Embedded in Layered Media. Optics Express 2010; 18(2): 1722-1733. 

Simsek E. On the Surface Plasmon Resonance Modes of Nanoparticle Chains and Arrays. Plasmonics 2009; 4(3): 223-230. 

Sinha BK, Simsek E, S. Asvadurov. Influence of a Pipe Tool on Borehole Modes in Fast and Slow Formations. Geophysics 2009; 74(3): E111. 

Liu QH, Y. Lin, Liu J, Lee JH, Simsek E. A 3-D Spectral Integral Method for Surface Integral Equations. IEEE Microwave and Wireless Component Letters 2009; 19(2): 62-64. 

Simsek E, Sinha BK. Analysis of Noncircular Fluid-Filled Boreholes in Elastic Formations using a Perturbation Model. The Journal of the Acoustical Society of America 2008; 124(1): 213-217. 

Crozier K, Togan E, Simsek E, Yang T. Experimental measurement of the dispersion relations of the surface plasmon modes of metal nanoparticle chains. Optics Express 2007; 15: 17482. 

Wei B, Simsek E, Yu C, Liu QH. Three-Dimensional Electromagnetic Nonlinear Inversion in Layered Media by a Hybrid Diagonal Tensor Approximation - Stabilized Biconjugate Gradient Fast Fourier Transform Method. Waves in Random and Complex Media 2007; 17(2): 129-147. 

Wei B, Simsek E, Liu QH. Improved diagonal tensor approximation (DTA) and hybrid DTA/BCGS-FFT method for accurate simulation of 3-D inhomogeneous objects in layered media. Waves in Random and Complex Media 2007; 17(1): 55-66. 

Sinha BK, Simsek E, Liu QH. Elastic wave propagation in deviated wells in anisotropic formations. Geophysics 2006; 71(6): 191-202.

Song LP, Simsek E, Liu QH. A Fast 2-D Volume Integral Equation Solver for Scattering from Inhomogeneous Objects in Layered Media. Microwave and Optical Technology Letters 2005; 47 (2): 128-134.

Simsek E, Liu J, Liu QH. A Spectral Integral Method and Hybrid SIM/FEM for Layered Media. IEEE Transactions on Microwave Theory and Techniques 2006; 54(11): 3878-3884. 

Simsek E, Liu J, Liu QH, A Spectral Integral Method (SIM) for Layered Media, IEEE Transactions on Antennas and Propagation 2006; 54(6): 1742-1749. 

Simsek E, Liu QH, Wei B. Singularity subtraction for evaluation of Green's functions for multilayer media. IEEE Transactions on Microwave Theory and Techniques 2006; 54(1): 216-225.

Patents

Patent 9,176,250: Estimation of Depletion or Injection Induced Reservoir Stresses Using Time-Lapse Sonic Data in Cased Holes (with BK Sinha).

Prior Experience

Assistant Professor, George Washington University, 2011-2017

Marie Curie Fellow & Assistant Professor, Bahcesehir University, 2008-2011

Post-doctoral Research Associate, Schlumberger-Doll Research Center, 2007-2008

Professional Affiliations

IEEE (Senior Member)

Project Experience

Electromagnetics

Development of:
  • Singularity extraction for fast evaluation of layered medium Green’s functions
  • Spectral Integral Method for homogeneous objects embedded in stratified media
  • Hybrid Finite Element – Spectral Integral Method for inhomogeneous objects embedded in stratified media
  • Layered-medium discrete dipole approximation
  • Simulation of various types of RF/microwave devices, RCS calculations, antenna design and optimization
  • Device metrology, anechoic chamber, network analyzer

Optics and Opto-Electronics

Design, fabrication, and characterization of:
  • Surface plasmon resonance sensors for biological and chemical substances
  • ITO and graphene based electro-optic modulators
  • Multilayered silicon substrate yielding maximum visibility for thin films
    Absorbers with Bragg stacks and metamaterials
  • Nano- and micro-fabrication via laser ablation
  • Reflection and transmission spectroscopy, Raman spectroscopy, interferometry, and photon-counting experiments
  • Light, scanning electron, and atomic force microscopy imaging
  • Photoconductivity measurements of interconnected nanowires
  • Electroluminescence and photoluminescence enhancement via nano antennas and quantum dots
  • Modeling excitons in transition-metal dichalcogenides

Geophysics

  • Evaluation of a pipe tool’s influence on borehole modes in fast and slow formations
  • Analysis of noncircular fluid-filled boreholes in elastic formations using a perturbation model
  • Investigation of elastic wave propagation in deviated wells in anisotropic formations
  • Estimation of depletion- or injection-induced changes in reservoir stresses using time-lapse sonic data
  • Identification of formation stress effects on wave propagation in boreholes

Software Engineering

  • Algorithm development in C, C++, FORTRAN, Assembly, R, and Python.
  • Debugging and acceleration.
  • Algorithm review