Publications by authors named "Hakan Bagci"

22 Publications

  • Page 1 of 1

An explicit marching-on-in-time scheme for solving the time domain Kirchhoff integral equation.

J Acoust Soc Am 2019 Sep;146(3):2068

Division of Computer, Electrical, and Mathematical Science and Engineering, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.

A fully explicit marching-on-in-time (MOT) scheme for solving the time domain Kirchhoff (surface) integral equation to analyze transient acoustic scattering from rigid objects is presented. A higher-order Nyström method and a PE(CE)-type ordinary differential equation integrator are used for spatial discretization and time marching, respectively. The resulting MOT scheme uses the same time step size as its implicit counterpart (which also uses Nyström method in space) without sacrificing from the accuracy and stability of the solution. Numerical results demonstrate the accuracy, efficiency, and applicability of the proposed explicit MOT solver.
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http://dx.doi.org/10.1121/1.5125259DOI Listing
September 2019

An FMM-FFT Accelerated SIE Simulator for Analyzing EM Wave Propagation in Mine Environments Loaded With Conductors.

IEEE J Multiscale Multiphys Comput Tech 2018 5;3:3-15. Epub 2018 Feb 5.

Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109 USA.

A fast and memory efficient three-dimensional full-wave simulator for analyzing electromagnetic (EM) wave propagation in electrically large and realistic mine tunnels/galleries loaded with conductors is proposed. The simulator relies on Muller and combined field surface integral equations (SIEs) to account for scattering from mine walls and conductors, respectively. During the iterative solution of the system of SIEs, the simulator uses a fast multipole method-fast Fourier transform (FMM-FFT) scheme to reduce CPU and memory requirements. The memory requirement is further reduced by compressing large data structures via singular value and Tucker decompositions. The efficiency, accuracy, and real-world applicability of the simulator are demonstrated through characterization of EM wave propagation in electrically large mine tunnels/galleries loaded with conducting cables and mine carts.
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http://dx.doi.org/10.1109/JMMCT.2018.2802420DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5928803PMC
February 2018

Epigenetic reprogramming enables the transition from primordial germ cell to gonocyte.

Nature 2018 03 7;555(7696):392-396. Epub 2018 Mar 7.

MRC London Institute of Medical Sciences (LMS), Du Cane Road, London W12 0NN, UK.

Gametes are highly specialized cells that can give rise to the next generation through their ability to generate a totipotent zygote. In mice, germ cells are first specified in the developing embryo around embryonic day (E) 6.25 as primordial germ cells (PGCs). Following subsequent migration into the developing gonad, PGCs undergo a wave of extensive epigenetic reprogramming around E10.5-E11.5, including genome-wide loss of 5-methylcytosine. The underlying molecular mechanisms of this process have remained unclear, leading to our inability to recapitulate this step of germline development in vitro. Here we show, using an integrative approach, that this complex reprogramming process involves coordinated interplay among promoter sequence characteristics, DNA (de)methylation, the polycomb (PRC1) complex and both DNA demethylation-dependent and -independent functions of TET1 to enable the activation of a critical set of germline reprogramming-responsive genes involved in gamete generation and meiosis. Our results also reveal an unexpected role for TET1 in maintaining but not driving DNA demethylation in gonadal PGCs. Collectively, our work uncovers a fundamental biological role for gonadal germline reprogramming and identifies the epigenetic principles of the PGC-to-gonocyte transition that will help to guide attempts to recapitulate complete gametogenesis in vitro.
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http://dx.doi.org/10.1038/nature25964DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5856367PMC
March 2018

Quantum-corrected transient analysis of plasmonic nanostructures.

Opt Express 2017 Mar;25(6):5891-5908

A time domain surface integral equation (TD-SIE) solver is developed for quantum-corrected analysis of transient electromagnetic field interactions on plasmonic nanostructures with sub-nanometer gaps. "Quantum correction" introduces an auxiliary tunnel to support the current path that is generated by electrons tunneled between the nanostructures. The permittivity of the auxiliary tunnel and the nanostructures is obtained from density functional theory (DFT) computations. Electromagnetic field interactions on the combined structure (nanostructures plus auxiliary tunnel connecting them) are computed using a TD-SIE solver. Time domain samples of the permittivity and the Green function required by this solver are obtained from their frequency domain samples (generated from DFT computations) using a semi-analytical method. Accuracy and applicability of the resulting quantum-corrected solver scheme are demonstrated via numerical examples.
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http://dx.doi.org/10.1364/OE.25.005891DOI Listing
March 2017

Transient analysis of electromagnetic wave interactions on plasmonic nanostructures using a surface integral equation solver.

J Opt Soc Am A Opt Image Sci Vis 2016 Sep;33(9):1747-59

Transient electromagnetic interactions on plasmonic nanostructures are analyzed by solving the Poggio-Miller-Chan-Harrington-Wu-Tsai (PMCHWT) surface integral equation (SIE). Equivalent (unknown) electric and magnetic current densities, which are introduced on the surfaces of the nanostructures, are expanded using Rao-Wilton-Glisson and polynomial basis functions in space and time, respectively. Inserting this expansion into the PMCHWT-SIE and Galerkin testing the resulting equation at discrete times yield a system of equations that is solved for the current expansion coefficients by a marching on-in-time (MOT) scheme. The resulting MOT-PMCHWT-SIE solver calls for computation of additional convolutions between the temporal basis function and the plasmonic medium's permittivity and Green function. This computation is carried out with almost no additional cost and without changing the computational complexity of the solver. Time-domain samples of the permittivity and the Green function required by these convolutions are obtained from their frequency-domain samples using a fast relaxed vector fitting algorithm. Numerical results demonstrate the accuracy and applicability of the proposed MOT-PMCHWT solver.
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http://dx.doi.org/10.1364/JOSAA.33.001747DOI Listing
September 2016

Ordered chromatin changes and human X chromosome reactivation by cell fusion-mediated pluripotent reprogramming.

Nat Commun 2016 08 10;7:12354. Epub 2016 Aug 10.

Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK.

Erasure of epigenetic memory is required to convert somatic cells towards pluripotency. Reactivation of the inactive X chromosome (Xi) has been used to model epigenetic reprogramming in mouse, but human studies are hampered by Xi epigenetic instability and difficulties in tracking partially reprogrammed iPSCs. Here we use cell fusion to examine the earliest events in the reprogramming-induced Xi reactivation of human female fibroblasts. We show that a rapid and widespread loss of Xi-associated H3K27me3 and XIST occurs in fused cells and precedes the bi-allelic expression of selected Xi-genes by many heterokaryons (30-50%). After cell division, RNA-FISH and RNA-seq analyses confirm that Xi reactivation remains partial and that induction of human pluripotency-specific XACT transcripts is rare (1%). These data effectively separate pre- and post-mitotic events in reprogramming-induced Xi reactivation and reveal a complex hierarchy of epigenetic changes that are required to reactivate the genes on the human Xi chromosome.
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http://dx.doi.org/10.1038/ncomms12354DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4987517PMC
August 2016

Mirror-backed Dark Alumina: A Nearly Perfect Absorber for Thermoelectronics and Thermophotovotaics.

Sci Rep 2016 Jan 28;6:19984. Epub 2016 Jan 28.

Department of Electrical and Computer Engineering, Wayne State University, Detroit, Michigan 48202, USA.

We present here a broadband, wide-angle, and polarization-independent nearly perfect absorber consisting of mirror-backed nanoporous alumina. By electrochemically anodizing the disordered multicomponent aluminum and properly tailoring the thickness and air-filling fraction of nanoporous alumina, according to the Maxwell-Garnet mixture theory, a large-area dark alumina can be made with excellent photothermal properties and absorption larger than 93% over a wide wavelength range spanning from near-infrared to ultraviolet light, i.e. 250 nm-2500 nm. The measured absorption is orders of magnitude greater than other reported anodized porous alumina, typically semi-transparent at similar wavelengths. This simple yet effective approach, however, does not require any lithography, nano-mixture deposition, pre- and post-treatment. Here, we also envisage and theoretically investigate the practical use of proposed absorbers and/or photothermal converters in integrated thermoelectronic and/or thermophotovoltaic energy conversion devices, which make efficient use of the entire spectrum of ambient visible to near-infrared radiation.
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http://dx.doi.org/10.1038/srep19984DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4730200PMC
January 2016

Jarid2 Coordinates Nanog Expression and PCP/Wnt Signaling Required for Efficient ESC Differentiation and Early Embryo Development.

Cell Rep 2015 Jul 16;12(4):573-86. Epub 2015 Jul 16.

Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK. Electronic address:

Jarid2 is part of the Polycomb Repressor complex 2 (PRC2) responsible for genome-wide H3K27me3 deposition. Unlike other PRC2-deficient embryonic stem cells (ESCs), however, Jarid2-deficient ESCs show a severe differentiation block, altered colony morphology, and distinctive patterns of deregulated gene expression. Here, we show that Jarid2(-/-) ESCs express constitutively high levels of Nanog but reduced PCP signaling components Wnt9a, Prickle1, and Fzd2 and lowered β-catenin activity. Depletion of Wnt9a/Prickle1/Fzd2 from wild-type ESCs or overexpression of Nanog largely phenocopies these cellular defects. Co-culture of Jarid2(-/-) with wild-type ESCs restores variable Nanog expression and β-catenin activity and can partially rescue the differentiation block of mutant cells. In addition, we show that ESCs lacking Jarid2 or Wnt9a/Prickle1/Fzd2 or overexpressing Nanog induce multiple ICM formation when injected into normal E3.5 blastocysts. These data describe a previously unrecognized role for Jarid2 in regulating a core pluripotency and Wnt/PCP signaling circuit that is important for ESC differentiation and for pre-implantation development.
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http://dx.doi.org/10.1016/j.celrep.2015.06.060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4534826PMC
July 2015

Graphene metascreen for designing compact infrared absorbers with enhanced bandwidth.

Nanotechnology 2015 Apr 31;26(16):164002. Epub 2015 Mar 31.

Department of Electrical and Computer Engineering, Wayne State University, Detroit, MI 48202, USA.

We propose a compact, wideband terahertz and infrared absorber, comprising a patterned graphene sheet on a thin metal-backed dielectric slab. This graphene-based nanostructure can achieve a low or negative effective permeability, necessary for realizing the perfect absorption. The dual-reactive property found in both the plasmonic graphene sheet and the grounded high-permittivity slab introduces extra poles into the equivalent circuit model of the system, thereby resulting in a dual-band or broadband magnetic resonance that enhances the absorption bandwidth. More interestingly, the two-dimensional patterned graphene sheet significantly simplifies the design and fabrication processes for achieving resonant magnetic response, and allows the frequency-reconfigurable operation via electrostatic gating.
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http://dx.doi.org/10.1088/0957-4484/26/16/164002DOI Listing
April 2015

A nonlinear plasmonic resonator for three-state all-optical switching.

Opt Express 2014 Mar;22(6):6966-75

A nonlinear plasmonic resonator design is proposed for three-state all-optical switching at frequencies including near infrared and lower red parts of the spectrum. The tri-stable response required for three-state operation is obtained by enhancing nonlinearities of a Kerr medium through multiple (higher order) plasmons excited on resonator's metallic surfaces. Indeed, simulations demonstrate that exploitation of multiple plasmons equips the proposed resonator with a multi-band tri-stable response, which cannot be obtained using existing nonlinear plasmonic devices that make use of single mode Lorentzian resonances. Multi-band three-state optical switching that can be realized using the proposed resonator has potential applications in optical communications and computing.
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http://dx.doi.org/10.1364/OE.22.006966DOI Listing
March 2014

An ultra-broadband multilayered graphene absorber.

Opt Express 2013 Dec;21(24):29938-48

An ultra-broadband multilayered graphene absorber operating at terahertz (THz) frequencies is proposed. The absorber design makes use of three mechanisms: (i) The graphene layers are asymmetrically patterned to support higher order surface plasmon modes that destructively interfere with the dipolar mode and generate electromagnetically induced absorption. (ii) The patterned graphene layers biased at different gate voltages backed-up with dielectric substrates are stacked on top of each other. The resulting absorber is polarization dependent but has an ultra-broadband of operation. (iii) Graphene's damping factor is increased by lowering its electron mobility to 1000 cm²/Vs. Indeed, numerical experiments demonstrate that with only three layers, bandwidth of 90% absorption can be extended upto 7THz, which is drastically larger than only few THz of bandwidth that can be achieved with existing metallic/graphene absorbers.
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http://dx.doi.org/10.1364/OE.21.029938DOI Listing
December 2013

Exciting graphene surface plasmon polaritons through light and sound interplay.

Phys Rev Lett 2013 Dec 5;111(23):237404. Epub 2013 Dec 5.

Division of Computer, Electrical, and Mathematical Sciences and Engineering, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.

We propose a concept that allows for efficient excitation of surface plasmon spolaritons (SPPs) on a thin graphene sheet located on a substrate by an incident electromagnetic field. Elastic vibrations of the sheet, which are generated by a flexural wave, act as a grating that enables the electromagnetic field to couple to propagating graphene SPPs. This scheme permits fast on-off switching of the SPPs and dynamic tuning of their excitation frequency by adjusting the vibration frequency (grating period). Potential applications include single molecule detection and enhanced control of SPP trajectories via surface wave patterning of graphene metasurfaces. Analytical calculations and numerical experiments demonstrate the practical applicability of the proposed concept.
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http://dx.doi.org/10.1103/PhysRevLett.111.237404DOI Listing
December 2013

Behavior of obliquely incident vector Bessel beams at planar interfaces.

J Opt Soc Am A Opt Image Sci Vis 2013 Jun;30(6):1172-9

We investigate the behavior of full-vector electromagnetic Bessel beams obliquely incident at an interface between two electrically different media. We employ a Fourier transform domain representation of Bessel beams to determine their behavior upon reflection and transmission. This transform, which is geometric in nature, consists of elliptical support curves with complex weighting associated with them. The behavior of the scattered field at an interface is highly complex, owing to its full-vector nature; nevertheless, this behavior has a straightforward representation in the transform domain geometry. The analysis shows that the reflected field forms a different vector Bessel beam, but in general, the transmitted field cannot be represented as a Bessel beam. Nevertheless, using this approach, we demonstrate a method to propagate a Bessel beam in the refractive medium by launching a non-Bessel beam at the interface. Several interesting phenomena related to the behavior of Bessel beams are illustrated, such as polarized reflection at Brewster's angle incidence, and the Goos-Hänchen and Imbert-Federov shifts in the case of total reflection.
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http://dx.doi.org/10.1364/JOSAA.30.001172DOI Listing
June 2013

Atypical heterochromatin organization and replication are rapidly acquired by somatic cells following fusion-mediated reprogramming by mouse ESCs.

Cell Cycle 2013 Oct 3;12(20):3253-61. Epub 2013 Sep 3.

Lymphocyte Development Group; MRC Clinical Sciences Centre; Imperial College London; London, UK.

We recently reported that mouse embryonic stem cells (ESCs) in S/G 2 are more efficient at reprogramming somatic cells than ESCs at other stages of the cell cycle. We also provided evidence that DNA replication is induced in the nuclei of somatic partners upon fusion with ESC partners, and showed that this was critical for their conversion toward a pluripotent state. (1) Here we have used counterflow centrifugal elutriation to enrich for ESCs at different cell cycle phases, so as to examine in detail the properties of S/G 2 phase cells. This revealed that the replication and organization of DAPI-intense heterochromatin in ESCs is unusual in two respects. First, replication of heterochromatin occurred earlier during S phase and was associated with precocious H3S10 phosphorylation. Second, heterochromatin protein 1 α (HP1α), which invariably marks DAPI-intense and H3K9me3-enriched pericentromeric domains in mouse somatic cells, (2) was not necessarily associated with these H3K9me3-enriched domains in undifferentiated ESCs. These data, which complement recent replication timing (3) and electron spectroscopic imaging (ESI) analyses, (4) suggest that heterochromatin is atypical in ESCs. Interestingly, as these unusual features were rapidly acquired by somatic nuclei upon ESC fusion-mediated reprogramming, our results suggest that fundamental changes in cell cycle structure and heterochromatin dynamics may be important for conferring pluripotency.
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http://dx.doi.org/10.4161/cc.26223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3885636PMC
October 2013

DNA demethylation in pluripotency and reprogramming: the role of tet proteins and cell division.

Cell Stem Cell 2013 Sep;13(3):265-9

Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK.

Cytosine methylation is found in the genomes of many plants and animals and has been associated with transcriptional silencing in mammals. At critical stages in embryo development, when cellular potential is reset, DNA methylation is lost in a series of "sequential waves." The mechanism underlying this is controversial and complex. Several new reports now suggest that TET enzymes and cell division are important for these in vivo transitions as well as for experimentally induced reprogramming.
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http://dx.doi.org/10.1016/j.stem.2013.08.005DOI Listing
September 2013

A 3D tunable and multi-frequency graphene plasmonic cloak.

Opt Express 2013 May;21(10):12592-603

Division of Computer, Electrical, and Mathematical Sciences and Engineering 4700 King Abdullah University of Science and Technology Thuwal 23955-6900, Saudi Arabia.

We demonstrate the possibility of cloaking three-dimensional objects at multi-frequencies in the far-infrared part of the spectrum. The proposed cloaking mechanism exploits graphene layers wrapped around the object to be concealed. Graphene layers are doped via a variable external voltage difference permitting continuous tuning of the cloaking frequencies. Particularly, two configurations are investigated: (i) Only one graphene layer is used to suppress the scattering from a dielectric sphere. (ii) Several of these layers biased at different gate voltages are used to achieve a multi-frequency cloak. These frequencies can be set independently. The proposed cloak's functionality is verified by near- and far-field computations. By considering geometry and material parameters that are realizable by practical experiments, we contribute to the development of graphene based plasmonic applications that may find use in disruptive photonic technologies.
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http://dx.doi.org/10.1364/OE.21.012592DOI Listing
May 2013

Different roles for Tet1 and Tet2 proteins in reprogramming-mediated erasure of imprints induced by EGC fusion.

Mol Cell 2013 Mar 28;49(6):1023-33. Epub 2013 Feb 28.

Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK.

Genomic imprinting directs the allele-specific marking and expression of loci according to their parental origin. Differential DNA methylation at imprinted control regions (ICRs) is established in gametes and, although largely preserved through development, can be experimentally reset by fusing somatic cells with embryonic germ cell (EGC) lines. Here, we show that the Ten-Eleven Translocation proteins Tet1 and Tet2 participate in the efficient erasure of imprints in this model system. The fusion of B cells with EGCs initiates pluripotent reprogramming, in which rapid re-expression of Oct4 is accompanied by an accumulation of 5-hydroxymethylcytosine (5hmC) at several ICRs. Tet2 was required for the efficient reprogramming capacity of EGCs, whereas Tet1 was necessary to induce 5-methylcytosine oxidation specifically at ICRs. These data show that the Tet1 and Tet2 proteins have discrete roles in cell-fusion-mediated pluripotent reprogramming and imprint erasure in somatic cells.
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http://dx.doi.org/10.1016/j.molcel.2013.01.032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3613797PMC
March 2013

DNA synthesis is required for reprogramming mediated by stem cell fusion.

Cell 2013 Feb;152(4):873-83

Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK.

Embryonic stem cells (ESCs) can instruct the conversion of differentiated cells toward pluripotency following cell-to-cell fusion by a mechanism that is rapid but poorly understood. Here, we used centrifugal elutriation to enrich for mouse ESCs at sequential stages of the cell cycle and showed that ESCs in S/G2 phases have an enhanced capacity to dominantly reprogram lymphocytes and fibroblasts in heterokaryon and hybrid assays. Reprogramming success was associated with an ability to induce precocious nucleotide incorporation within the somatic partner nuclei in heterokaryons. BrdU pulse-labeling experiments revealed that virtually all successfully reprogrammed somatic nuclei, identified on the basis of Oct4 re-expression, had undergone DNA synthesis within 24 hr of fusion with ESCs. This was essential for successful reprogramming because drugs that inhibited DNA polymerase activity effectively blocked pluripotent conversion. These data indicate that nucleotide incorporation is an early and critical event in the epigenetic reprogramming of somatic cells in experimental ESC-heterokaryons.
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http://dx.doi.org/10.1016/j.cell.2013.01.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3605571PMC
February 2013

Modulation of propagation-invariant Localized Waves for FSO communication systems.

Opt Express 2012 Jul;20(14):15126-38

Division of Physical Sciences and Engineering, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.

The novel concept of spatio-temporal modulation of Nyquist pulses is introduced, and the resulting wave-packets are termed Nyquist Localized Waves (LWs). Ideal Nyquist LWs belong to the generic family of LW solutions and can propagate indefinitely in unbounded media without attenuation or chromatic dispersion. The possibility of modulating Nyquist LWs for free-space optical (FSO) communication systems is demonstrated using two different modulation techniques. The first technique is on-off keying (OOK) with alternate mark inversion (AMI) coding for 1-bit per symbol transmission, and the second one is 16-ary quadrature amplitude modulation (16-QAM) for 4-bits per symbol transmission. Aspects related to the performance, detection and generation of the spatio-temporally coupled wave-packets are discussed and future research directions are outlined.
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http://dx.doi.org/10.1364/OE.20.015126DOI Listing
July 2012

Reflection and transmission of normally incident full-vector X waves on planar interfaces.

J Opt Soc Am A Opt Image Sci Vis 2012 Jan;29(1):139-52

Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.

The reflection and transmission of full-vector X waves normally incident on planar half-spaces and slabs are studied. For this purpose, X waves are expanded in terms of weighted vector Bessel beams; this new decomposition and reconstruction method offers a more lucid and intuitive interpretation of the physical phenomena observed upon the reflection or transmission of X waves when compared to the conventional plane-wave decomposition technique. Using the Bessel beam expansion approach, we have characterized changes in the field shape and the intensity distribution of the transmitted and reflected full-vector X waves. We have also identified a novel longitudinal shift, which is observed when a full-vector X wave is transmitted through a dielectric slab under frustrated total reflection condition. The results of our studies presented here are valuable in understanding the behavior of full-vector X waves when they are utilized in practical applications in electromagnetics, optics, and photonics, such as trap and tweezer setups, optical lithography, and immaterial probing.
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http://dx.doi.org/10.1364/JOSAA.29.000139DOI Listing
January 2012

Energy flow characteristics of vector X-Waves.

Opt Express 2011 Apr;19(9):8526-32

Division of Physical Sciences and Engineering, 4700 King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.

The vector form of X-Waves is obtained as a superposition of transverse electric and transverse magnetic polarized field components. It is shown that the signs of all components of the Poynting vector can be locally changed using carefully chosen complex amplitudes of the transverse electric and transverse magnetic polarization components. Negative energy flux density in the longitudinal direction can be observed in a bounded region around the centroid; in this region the local behavior of the wave field is similar to that of wave field with negative energy flow. This peculiar energy flux phenomenon is of essential importance for electromagnetic and optical traps and tweezers, where the location and momenta of micro-and nanoparticles are manipulated by changing the Poynting vector, and in detection of invisibility cloaks.
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http://dx.doi.org/10.1364/OE.19.008526DOI Listing
April 2011

On the propagation of truncated localized waves in dispersive silica.

Opt Express 2010 Dec;18(25):25482-93

Division of Physical Sciences and Engineering, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.

Propagation characteristics of truncated Localized Waves propagating in dispersive silica and free space are numerically analyzed. It is shown that those characteristics are affected by the changes in the relation between the transverse spatial spectral components and the wave vector. Numerical experiments demonstrate that as the non-linearity of this relation gets stronger, the pulses propagating in silica become more immune to decay and distortion whereas the pulses propagating in free-space suffer from early decay and distortion.
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http://dx.doi.org/10.1364/OE.18.025482DOI Listing
December 2010