WorldWideScience

Sample records for high-q terahertz metamaterials

  1. High-Q terahertz reconfigurable metamaterials using graphene

    Science.gov (United States)

    Arezoomandan, Sara; Sensale Rodriguez, Berardi

    2016-09-01

    We propose and discuss high-Q reconfigurable metamaterials based on graphene. The key components of the device are periodic concentric metallic ring resonators with interdigitated fingers, which are placed in-between the rings and provide for the large Q in the metamaterial, as well as several strategically located gaps where active graphene sheets are placed. We can easily adjust the frequency response of the metamaterial by means of varying a couple of parameters, such as the ring dimensions, number of fingers, etc., but also dynamically by means of varying conductivity in graphene.

  2. Terahertz metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hou-tong [Los Alamos National Laboratory; Taylor, Antoineete J [Los Alamos National Laboratory; Azad, Abul K [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory

    2009-01-01

    In this paper we present our recent developments in terahertz (THz) metamaterials and devices. Planar THz metamaterials and their complementary structures fabricated on suitable substrates have shown electric resonant response, which causes the band-pass or band-stop property in THz transmission and reflection. The operational frequency can be further tuned up to 20% upon photoexcitation of an integrated semiconductor region in the splitring resonators as the metamaterial elements. On the other hand, the use of semiconductors as metamaterial substrates enables dynamical control of metamaterial resonances through photoexcitation, and reducing the substrate carrier lifetime further enables an ultrafast switching recovery. The metamaterial resonances can also be actively controlled by application of a voltage bias when they are fabricated on semiconductor substrates with appropriate doping concentration and thickness. Using this electrically driven approach, THz modulation depth up to 80% and modulation speed of 2 MHz at room temperature have been demonstrated, which suggests practical THz applications.

  3. Metamaterials for terahertz polarimetric devices

    Energy Technology Data Exchange (ETDEWEB)

    O' hara, John F [Los Alamos National Laboratory; Taylor, Antoinette J [Los Alamos National Laboratory; Smirnova, Evgenya [Los Alamos National Laboratory; Azad, Abul [Los Alamos National Laboratory

    2008-01-01

    We present experimental and numerical investigations of planar terahertz metamaterial structures designed to interact with the state of polarization. The dependence of metamaterial resonances on polarization results in unique amplitude and phase characteristics of the terahertz transmission, providing the basis for polarimetric terahertz devices. We highlight some potential applications for polarimetric devices and present simulations of a terahertz quarter-wave plate and a polarizing terahertz beam splitter. Although this work was performed at terahertz frequencies, it may find applications in other frequency ranges as well.

  4. Active terahertz metamaterial devices

    Science.gov (United States)

    Chen, Houtong; Padilla, Willie John; Averitt, Richard Douglas; O'Hara, John F.; Lee, Mark

    2010-11-02

    Metamaterial structures are taught which provide for the modulation of terahertz frequency signals. Each element within an array of metamaterial (MM) elements comprises multiple loops and at least one gap. The MM elements may comprise resonators with conductive loops and insulated gaps, or the inverse in which insulated loops are present with conductive gaps; each providing useful transmissive control properties. The metamaterial elements are fabricated on a semiconducting substrate configured with a means of enhancing or depleting electrons from near the gaps of the MM elements. An on to off transmissivity ratio of about 0.5 is achieved with this approach. Embodiments are described in which the MM elements incorporated within a Quantum Cascade Laser (QCL) to provide surface emitting (SE) properties.

  5. Metamaterials for terahertz polarimetric devices

    Energy Technology Data Exchange (ETDEWEB)

    O' hara, John F [Los Alamos National Laboratory; Taylor, Antoinette J [Los Alamos National Laboratory; Smirnova, Evgenya [Los Alamos National Laboratory; Azad, Abul [Los Alamos National Laboratory; Chen, Hou-tong [Los Alamos National Laboratory; Peralta, Xomalin G [SNL; Brener, Igal [SNL

    2008-01-01

    We present experimental and numerical investigations of planar terahertz metamaterial structures designed to interact with the state of polarization. The dependence of metamaterial resonances on polarization results in unique amplitude and phase characteristics of the terahertz transmission, providing the basis for polarimetric terahertz devices. We highlight some potential applications for polarimetric devices and present simulations of a terahertz quarter-wave plate and a polarizing terahertz beam splitter. Although this work was performed at tcrahertz frequencies, it may find applications in other frequency ranges as well.

  6. A Perfect Terahertz Metamaterial Absorber

    OpenAIRE

    Bagheri, Alireza; Moradi, Gholamreza

    2015-01-01

    In this paper the design for an absorbing metamaterial with near unity absorbance in terahertz region is presented. The absorber's unit cell structure consists of two metamaterial resonators that couple to electric and magnetic fields separately. The structure allows us to maximize absorption by varying dielectric material and thickness and, hence the effective electrical permittivity and magnetic permeability.

  7. Polarization insensitive terahertz metamaterial absorber.

    Science.gov (United States)

    Grant, J; Ma, Y; Saha, S; Lok, L B; Khalid, A; Cumming, D R S

    2011-04-15

    We present the simulation, implementation, and measurement of a polarization insensitive resonant metamaterial absorber in the terahertz region. The device consists of a metal/dielectric-spacer/metal structure allowing us to maximize absorption by varying the dielectric material and thickness and, hence, the effective electrical permittivity and magnetic permeability. Experimental absorption of 77% and 65% at 2.12 THz (in the operating frequency range of terahertz quantum cascade lasers) is observed for a spacer of polyimide or silicon dioxide respectively. These metamaterials are promising candidates as absorbing elements for thermally based terahertz imaging.

  8. Terahertz antireflection coatings using metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hou-tong [Los Alamos National Laboratory; Zhou, Jiangfeng [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Azad, Abul K [Los Alamos National Laboratory; Chen, Frank [Los Alamos National Laboratory; Taylor, Antoinette J [Los Alamos National Laboratory

    2010-01-01

    We demonstrate terahertz metamaterial antireflection coatings (ARCs) that significantly reduce the reflection and enhance the transmission at an interface of dielectric media. They are able to operate over a wide range of incidence angles for both TM and TE polarizations. Experiments and finite-element simulations will be presented and discussed.

  9. Asymmetric planar terahertz metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ramjan [Los Alamos National Laboratory; Al - Naib, Ibraheem A. I. [PHILIPPS UNIV; Koch, Martin [PHILIPPS UNIV; Zhang, Weili [OKLAHOMA STATE UNIV

    2010-01-01

    Using terahertz time-domain spectroscopy, we report an experimental observation of three distinct resonances in split ring resonators (SRRs) for both vertical and horizontal electric field polarizations at normal incidence. Breaking the symmetry in SRRs by gradually displacing the capacitive gap from the centre towards the comer of the ring allows for an 85% modulation of the fundamental inductive-capacitive (LC) resonance. Increasing asymmetry leads to the evolution of an otherwise inaccessible high quality factor electric quadrupole resonance that can be exploited for bio-sensing applications in the terahertz region.

  10. Reconfigurable metamaterials for terahertz wave manipulation

    Science.gov (United States)

    Hashemi, Mohammed R.; Cakmakyapan, Semih; Jarrahi, Mona

    2017-09-01

    Reconfigurable metamaterials have emerged as promising platforms for manipulating the spectral and spatial properties of terahertz waves without being limited by the characteristics of naturally existing materials. Here, we present a comprehensive overview of various types of reconfigurable metamaterials that are utilized to manipulate the intensity, phase, polarization, and propagation direction of terahertz waves. We discuss various reconfiguration mechanisms based on optical, electrical, thermal, and mechanical stimuli while using semiconductors, superconductors, phase-change materials, graphene, and electromechanical structures. The advantages and disadvantages of different reconfigurable metamaterial designs in terms of modulation efficiency, modulation bandwidth, modulation speed, and system complexity are discussed in detail.

  11. High-Q lattice mode matched structural resonances in terahertz metasurfaces

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ningning; Zhang, Weili, E-mail: weili.zhang@okstate.edu [School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078 (United States); Singh, Ranjan, E-mail: ranjans@ntu.edu.sg [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Centre for Disruptive Photonic Technologies, The Photonics Institute, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2016-07-11

    The quality (Q) factor of metamaterial resonances is limited by the radiative and non-radiative losses. At terahertz frequencies, the dominant loss channel is radiative in nature since the non-radiative losses are low due to high conductivity of metals. Radiative losses could be suppressed by engineering the meta-atom structure. However, such suppression usually occurs at the fundamental resonance mode which is typically a closed mode resonance such as an inductive-capacitive resonance or a Fano resonance. Here, we report an order of magnitude enhancement in Q factor of all the structural eigenresonances of a split-ring resonator fueled by the lattice mode matching. We match the fundamental order diffractive mode to each of the odd and even eigenresonances, thus leading to a tremendous line-narrowing of all the resonances. Such precise tailoring and control of the structural resonances in a metasurface lattice could have potential applications in low-loss devices, sensing, and design of high-Q metamaterial cavities.

  12. Polarization insensitive, broadband terahertz metamaterial absorber.

    Science.gov (United States)

    Grant, James; Ma, Yong; Saha, Shimul; Khalid, Ata; Cumming, David R S

    2011-09-01

    We present the simulation, implementation, and measurement of a polarization insensitive broadband resonant terahertz metamaterial absorber. By stacking metal-insulator layers with differing structural dimensions, three closely positioned resonant peaks are merged into one broadband absorption spectrum. Greater than 60% absorption is obtained across a frequency range of 1.86 THz where the central resonance frequency is 5 THz. The FWHM of the device is 48%, which is two and half times greater than the FWHM of a single layer structure. Such metamaterials are promising candidates as absorbing elements for bolometric terahertz imaging.

  13. Three-dimensional broadband tunable terahertz metamaterials

    DEFF Research Database (Denmark)

    Fan, Kebin; Strikwerda, Andrew; Zhang, Xin

    2013-01-01

    We present optically tunable magnetic three-dimensional (3D) metamaterials at terahertz (THz) frequencies which exhibit a tuning range of ~30% of the resonance frequency. This is accomplished by fabricating 3D array structures consisting of double-split-ring resonators (DSRRs) on silicon on sapph......We present optically tunable magnetic three-dimensional (3D) metamaterials at terahertz (THz) frequencies which exhibit a tuning range of ~30% of the resonance frequency. This is accomplished by fabricating 3D array structures consisting of double-split-ring resonators (DSRRs) on silicon...

  14. Narrowband Metamaterial Absorber for Terahertz Secure Labeling

    Science.gov (United States)

    Nasr, Magued; Richard, Jonathan T.; Skirlo, Scott A.; Heimbeck, Martin S.; Joannopoulos, John D.; Soljacic, Marin; Everitt, Henry O.; Domash, Lawrence

    2017-09-01

    Flexible metamaterial films, fabricated by photolithography on a thin copper-backed polyimide substrate, are used to mark or barcode objects securely. The films are characterized by continuous-wave terahertz spectroscopic ellipsometry and visualized by a scanning confocal imager coupled to a vector network analyzer that constructed a terahertz spectral hypercube. These films exhibit a strong, narrowband, polarization- and angle-insensitive absorption at wavelengths near 1 mm. Consequently, the films are nearly indistinguishable at visible or infrared wavelengths and may be easily observed by terahertz imaging only at the resonance frequency of the film.

  15. Active metamaterials terahertz modulators and detectors

    CERN Document Server

    Rout, Saroj

    2017-01-01

    This book covers the theoretical background and experimental methods for engineers and physicist to be able to design, fabricate and characterize terahertz devices using metamaterials. Devices utilize mainstream semiconductor foundry processes to make them for communication and imaging applications. This book will provide engineers and physicists a comprehensive reference to construct such devices with general background in circuits and electromagnetics. The authors describe the design and construction of electromagnetic (EM) devices for terahertz frequencies (108-1010cycles/sec) by embedding solid state electronic devices into artificial metamaterials where each unit cell is only a fraction of the wavelength of the incident EM wave. The net effect is an electronically tunable bulk properties with effective electric (permittivity) and magnetic (permeability) that can be utilized to make novel devices to fill the terahertz gap.

  16. A new class of electrically tunable metamaterial terahertz modulators.

    Science.gov (United States)

    Yan, Rusen; Sensale-Rodriguez, Berardi; Liu, Lei; Jena, Debdeep; Xing, Huili Grace

    2012-12-17

    Switchable metamaterials offer unique solutions for efficiently manipulating electromagnetic waves, particularly for terahertz waves, which has been difficult since naturally occurring materials rarely respond to terahertz frequencies controllably. However, few terahertz modulators demonstrated to date exhibit simultaneously low attenuation and high modulation depth. In this letter we propose a new class of electrically-tunable terahertz metamaterial modulators employing metallic frequency-selective-surfaces (FSS) in conjunction with capacitively-tunable layers of electrons, promising near 100% modulation depth and graphene, Si, MoS(2), oxides etc, thus opening up myriad opportunities for realizing high performance switchable metamaterials over an ultra-wide terahertz frequency range.

  17. Equivalent circuit analysis of terahertz metamaterial filters

    KAUST Repository

    Zhang, Xueqian

    2011-01-01

    An equivalent circuit model for the analysis and design of terahertz (THz) metamaterial filters is presented. The proposed model, derived based on LMC equivalent circuits, takes into account the detailed geometrical parameters and the presence of a dielectric substrate with the existing analytic expressions for self-inductance, mutual inductance, and capacitance. The model is in good agreement with the experimental measurements and full-wave simulations. Exploiting the circuit model has made it possible to predict accurately the resonance frequency of the proposed structures and thus, quick and accurate process of designing THz device from artificial metamaterials is offered. ©2011 Chinese Optics Letters.

  18. Waveguide-based terahertz metamaterial functional components

    Science.gov (United States)

    Wang, Z. G.; Zhou, Y. Q.; Yang, L. M.; Gong, Cheng

    2017-09-01

    We suggest a flexible platform based on waveguides for constructing metamaterial functional components which work in the terahertz waveband. The properties of the components can be changed by selecting the specified metamaterial resonance structures on the waveguide’s narrow wall. In the paper, metallic circular patches are used as resonance structures to design the functional component which can be configured as a filter or absorber. The simulation and experimental results demonstrate that the component’s attenuation and absorption bandwidth can be configured by changing the quantities and sizes of the resonance structures.

  19. Graphene and Graphene Metamaterials for Terahertz Absorbers

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Pizzocchero, Filippo; Booth, Tim

    2013-01-01

    Graphene, due to the possibility to tune its conductivity, is the promising material for a range of the terahertz (THz) applications, such as tunable reflectors, absorbers, modulators, filters and polarization converters. Subwavelength structuring of graphene in order to form metamaterials allows...... for even more control over the THz waves. In this poster presentation I will show an elegant way to describe the graphene metamaterials and the design of graphene based absorbers. I will also present our recent experimental results on the graphene absorbers characterization....

  20. Terahertz broadband polarization converter based on metamaterials

    Science.gov (United States)

    Li, Yonghua; Zhao, Guozhong

    2018-01-01

    Based on the metamaterial composed of symmetrical split resonant ring, a broadband reflective terahertz polarization converter is proposed. The numerical simulation shows that it can rotate the polarization direction of linear polarized wave 90° in the range of 0.7-1.8THz and the polarization conversion ratio is over 90%. The reflection coefficient of the two electric field components in the diagonal direction is the same and the phase difference is 180° ,which leads to the cross-polarization rotation.In order to further study the physical mechanism of high polarization conversion, we analyze the surface current distribution of the resonant ring. The polarization converter has potential applications in terahertz wave plate and metamaterial antenna design.

  1. Theoretical and experimental study of high-Q resonant modes in terahertz optical systems

    NARCIS (Netherlands)

    Jellema, Willem; Withington, S.; Trappe, Neil; Murphy, J. A.; Wild, Wolfgang

    2004-01-01

    The existence of multiple reflections in terahertz optical system causes numerous problems in applications ranging from astronomical to medical instrumentation. We have performed a detailed theoretical study, using waveguide and free-space modal matching, of the high-Q modes that appear on THz

  2. Graphene plasmonics for tunable terahertz metamaterials.

    Science.gov (United States)

    Ju, Long; Geng, Baisong; Horng, Jason; Girit, Caglar; Martin, Michael; Hao, Zhao; Bechtel, Hans A; Liang, Xiaogan; Zettl, Alex; Shen, Y Ron; Wang, Feng

    2011-09-04

    Plasmons describe collective oscillations of electrons. They have a fundamental role in the dynamic responses of electron systems and form the basis of research into optical metamaterials. Plasmons of two-dimensional massless electrons, as present in graphene, show unusual behaviour that enables new tunable plasmonic metamaterials and, potentially, optoelectronic applications in the terahertz frequency range. Here we explore plasmon excitations in engineered graphene micro-ribbon arrays. We demonstrate that graphene plasmon resonances can be tuned over a broad terahertz frequency range by changing micro-ribbon width and in situ electrostatic doping. The ribbon width and carrier doping dependences of graphene plasmon frequency demonstrate power-law behaviour characteristic of two-dimensional massless Dirac electrons. The plasmon resonances have remarkably large oscillator strengths, resulting in prominent room-temperature optical absorption peaks. In comparison, plasmon absorption in a conventional two-dimensional electron gas was observed only at 4.2 K (refs 13, 14). The results represent a first look at light-plasmon coupling in graphene and point to potential graphene-based terahertz metamaterials.

  3. Broadband plasmon induced transparency in terahertz metamaterials

    KAUST Repository

    Zhu, Zhihua

    2013-04-25

    Plasmon induced transparency (PIT) could be realized in metamaterials via interference between different resonance modes. Within the sharp transparency window, the high dispersion of the medium may lead to remarkable slow light phenomena and an enhanced nonlinear effect. However, the transparency mode is normally localized in a narrow frequency band, which thus restricts many of its applications. Here we present the simulation, implementation, and measurement of a broadband PIT metamaterial functioning in the terahertz regime. By integrating four U-shape resonators around a central bar resonator, a broad transparency window across a frequency range greater than 0.40 THz is obtained, with a central resonance frequency located at 1.01 THz. Such PIT metamaterials are promising candidates for designing slow light devices, highly sensitive sensors, and nonlinear elements operating over a broad frequency range. © 2013 IOP Publishing Ltd.

  4. Plasmonic Terahertz Amplification in Graphene-Based Asymmetric Hyperbolic Metamaterial

    Directory of Open Access Journals (Sweden)

    Igor Nefedov

    2015-05-01

    Full Text Available We propose and theoretically explore terahertz amplification, based on stimulated generation of plasmons in graphene asymmetric hyperbolic metamaterials (AHMM, strongly coupled to terahertz radiation. In contrast to the terahertz amplification in resonant nanocavities, AHMM provides a wide-band THz amplification without any reflection in optically thin graphene multilayers.

  5. Plasmon induced transparency in graphene based terahertz metamaterials

    OpenAIRE

    Devi, Koijam Monika; Islam, M.; Chowdhury, Dibakar R.; Sarma, Amarendra K.; Kumar, Gagan

    2017-01-01

    Plasmon induced transparency (PIT) effect in a terahertz graphene metamaterial is numerically and theoretically analyzed. The proposed metamaterial comprises of a pair of graphene split ring resonators placed alternately on both sides of a graphene strip of nanometer scale. The PIT effect in the graphene metamaterial is studied for different vertical and horizontal configurations. Our results reveal that there is no PIT effect in the graphene metamaterial when the centers of both the split ri...

  6. Effective Surface Conductivity Approach for Graphene Metamaterials Based Terahertz Devices

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Pizzocchero, Filippo; Booth, Tim

    2013-01-01

    We propose a description of graphene metamaterials properties through the effective surface conductivity. On the example of tunable absorber we demonstrate that this approach allows for fast and efficient design of functional terahertz devices.......We propose a description of graphene metamaterials properties through the effective surface conductivity. On the example of tunable absorber we demonstrate that this approach allows for fast and efficient design of functional terahertz devices....

  7. Tunable reflecting terahertz filter based on chirped metamaterial structure.

    Science.gov (United States)

    Yang, Jing; Gong, Cheng; Sun, Lu; Chen, Ping; Lin, Lie; Liu, Weiwei

    2016-12-12

    Tunable reflecting terahertz bandstop filter based on chirped metamaterial structure is demonstrated by numerical simulation. In the metamaterial, the metal bars are concatenated to silicon bars with different lengths. By varying the conductivity of the silicon bars, the reflectivity, central frequency and bandwidth of the metamaterial could be tuned. Light illumination could be introduced to change the conductivity of the silicon bars. Numerical simulations also show that the chirped metamaterial structure is insensitive to the incident angle and polarization-dependent. The proposed chirped metamaterial structure can be operated as a tunable bandstop filter whose modulation depth, bandwidth, shape factor and center frequency can be controlled by light pumping.

  8. Terahertz metamaterials for linear polarization conversion and anomalous refraction.

    Science.gov (United States)

    Grady, Nathaniel K; Heyes, Jane E; Chowdhury, Dibakar Roy; Zeng, Yong; Reiten, Matthew T; Azad, Abul K; Taylor, Antoinette J; Dalvit, Diego A R; Chen, Hou-Tong

    2013-06-14

    Polarization is one of the basic properties of electromagnetic waves conveying valuable information in signal transmission and sensitive measurements. Conventional methods for advanced polarization control impose demanding requirements on material properties and attain only limited performance. We demonstrated ultrathin, broadband, and highly efficient metamaterial-based terahertz polarization converters that are capable of rotating a linear polarization state into its orthogonal one. On the basis of these results, we created metamaterial structures capable of realizing near-perfect anomalous refraction. Our work opens new opportunities for creating high-performance photonic devices and enables emergent metamaterial functionalities for applications in the technologically difficult terahertz-frequency regime.

  9. Tunable terahertz metamaterial with a graphene reflector

    Science.gov (United States)

    Deng, Guangsheng; Xia, Tianyu; Yang, Jun; Qiu, Longzhen; Yin, Zhiping

    2016-11-01

    An hybrid graphene/metamaterial(MM) structure by directly depositing single-layer graphene on bottom of a SiO2/Si substrate of the electric ring resonators is proposed and theoretically investigated in the terahertz(THz) region. Our calculated results show that the presence of the graphene strongly changes the THz MM transmittance in the frequency range from 0.1 to 1.7 THz, and a modulation depth of 80% or above is reached on the whole frequency range except a narrow band. The tunability of the proposed structure is mainly dependent on the transmission bands between two neighboring resonance frequencies, which is different from the conventional graphene MM structure based on single resonance dip. Moreover, the energy absorption in graphene layer plays an important role in THz wave modulation. This easy-to-fabricate structure shows potential applications in developing broadband transmission modulators and sensors.

  10. Review on Polarization Selective Terahertz Metamaterials: from Chiral Metamaterials to Stereometamaterials

    Science.gov (United States)

    Philip, Elizabath; Zeki Güngördü, M.; Pal, Sharmistha; Kung, Patrick; Kim, Seongsin Margaret

    2017-09-01

    In this article, recent progress and development of terahertz chiral metamaterials including stereometamaterials are thoroughly reviewed. This review mainly focuses on the fundamental principles of design and arrangement of meta-atoms in metamaterials exhibiting chirality with various asymmetry and symmetry and 2D and 3D configuration. Related optical and propagation properties in chiral metamaterials, such as optical activity, circular dichroism, and negative refraction for each different chiral metamaterials, are compared and investigated. Finally, comparison between chiral metamaterials with stereometamaterials in terms of the polarization selective operation along with the similarity and the distinction is addressed as well.

  11. Controlling Gigahertz and Terahertz Surface Electromagnetic Waves with Metamaterial Resonators

    Directory of Open Access Journals (Sweden)

    W.-C. Chen

    2011-12-01

    Full Text Available We computationally and experimentally investigate the use of metamaterial resonators as bandpass filters and other components that enable control of guided surface electromagnetic waves. The guided surface electromagnetic wave propagates on a planar Goubau line, launched via a coplanar waveguide coupler with 50Ω impedance. Experimental samples targeted for either microwave or terahertz frequencies are measured and shown to be in excellent agreement with simulations. Metamaterial elements are designed to absorb energy only of the planar Goubau line and yield narrow-band resonances with relatively high quality factors. Two independent configurations of coupled metamaterial elements are demonstrated that modify the otherwise flat transmission spectrum of the planar Goubau line. By physically shunting the capacitive gaps of the coupled metamaterial elements, we demonstrate the potential for a large dynamic range in transmissivity, suggesting the use of this configuration for high-bandwidth terahertz communications.

  12. Terahertz wave manipulation with metamaterials based on metal and graphene

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Zalkovskij, Maksim

    2013-01-01

    The terahertz (THz) technology provides with exciting possibilities for spectroscopy, food quality control, defense, communication and biomedical imaging [1]. Being relatively young (the massive exploitation of the THz range began only in the beginning of 1990-ies), the THz science demands...... for active and passive materials and devices. Metamaterials, metal-dielectric artificial composites, propose wide possibilities for achieving unconventional electromagnetic properties, not found in nature. Moreover, metamaterials constructed of graphene, a monolayer of carbon atoms, allow for tunable...

  13. Distinguishing octane grades in gasoline using terahertz metamaterials.

    Science.gov (United States)

    Li, J; Tian, Z; Chen, Y; Cao, W; Zeng, Z

    2012-06-01

    Distinguishing octane numbers of commercial gasoline is experimentally demonstrated by use of single split-ring resonator metamaterials functioning at terahertz frequencies. The differences in frequency-dependent absorption coefficients and refractive indices of various grades of gasoline lead to a modification in the surrounding dielectric environment and consequently the resonance properties of the planar metamaterials. This consequently enables a distinct frequency shift in the inductive-capacitive electric dipolar resonances. This paper reveals that such metamaterial arrays, as highly sensitive chemical sensors, have promising potential in petroleum industrial applications.

  14. Nanoparticles doped film sensing based on terahertz metamaterials

    Science.gov (United States)

    Liu, Weimin; Fan, Fei; Chang, Shengjiang; Hou, Jiaqing; Chen, Meng; Wang, Xianghui; Bai, Jinjun

    2017-12-01

    A nanoparticles concentration sensor based on doped film and terahertz (THz) metamaterial has been proposed. By coating the nanoparticles doped polyvinyl alcohol (PVA) film on the surface of THz metamaterial, the effects of nanoparticle concentration on the metamaterial resonances are investigated through experiments and numerical simulations. Results show that resonant frequency of the metamaterial linearly decreases with the increment of doping concentration. Furthermore, numerical simulations illustrate that the redshift of resonance results from the changes of refractive index of the doped film. The concentration sensitivity of this sensor is 3.12 GHz/0.1%, and the refractive index sensitivity reaches 53.33 GHz/RIU. This work provides a non-contact, nondestructive and sensitive method for the detection of nanoparticles concentration and brings out a new application on THz film metamaterial sensing.

  15. Ultrasensitive Terahertz Waveguide Modulators Using Multilayer Graphene Metamaterials

    DEFF Research Database (Denmark)

    Khromova, I.; Andryieuski, Andrei; Lavrinenko, Andrei

    2014-01-01

    We study terahertz-infrared electromagnetic properties of multilayer graphene- dielectric metamaterial and present novel waveguide-based devices: modulators with high mod- ulation depth ( > 38 dB at 0 : 07 eV graphene’s Fermi energy change) or extreme sensitivity (mod- ulation depth of > 13 : 2 d...

  16. Enhanced quadruple-resonant terahertz metamaterial with asymmetric hybrid resonators

    Science.gov (United States)

    Shi, Minglei; Lan, Feng; Mazumder, Pinaki; Aghadjani, Mahdi; Yang, Ziqiang; Meng, Lin; Zhou, Jun

    2018-01-01

    This paper presents the design, fabrication and investigation of a quadruple-resonant terahertz metamaterial that comprises two different Electric-inductance capacitance (ELC) resonators in a vertical configuration. Owing to asymmetric electric field coupling between the two resonators, the combined structure exhibits better performance in terms of transmission minima and bandwidths than the individual particles. The distributions of the surface current and electric field reveal quasi-quadrupole resonance, electric dipolar resonance and coupling between these resonances at different resonant frequencies. Moreover, the resonant frequencies are tunable by adjusting the corresponding geometrical parameters. Above all, the excellent performance of the proposed structure makes it promising for application in multiband terahertz devices.

  17. Graphene active plasmonic metamaterials for new types of terahertz lasers

    Science.gov (United States)

    Otsuji, Taiichi; Watanabe, Takayuki; Satou, Akira; Popov, Vyacheslav; Ryzhii, Victor

    2013-05-01

    This paper reviews recent advances in graphene active plasmonic metamaterials for new types of terahertz lasers. We theoretically discovered that when the population of Dirac Fermionic carriers in graphene are inverted by optical or electrical pumping the excitation of graphene plasmons by the THz photons results in propagating surface plasmon polaritons with giant gain in a wide THz range. Furthermore, when graphene is patterned in a micro- or nano-ribbon array by grating gate metallization, the structure acts as an active plasmonic metamaterial, providing a super-radiant plasmonic lasing with giant gain at the plasmon modes in a wide THz frequency range.

  18. Electrically tunable terahertz metamaterials based on graphene stacks array

    Science.gov (United States)

    Liu, Hanqing; Liu, Peiguo; Bian, Li-an; Liu, Chenxi; Zhou, Qihui; Chen, Yuwei

    2017-12-01

    With the ability of tuning chemical potential via gate voltage, the permittivity of graphene stack can be dynamically adjusted over a wide range. In this paper, we design electrically tunable metamaterials based on the graphene/Al2O3 stacks array, which can achieve a good modulation of resonant frequency and peak value in terahertz region. Due to the enlargement of plasmonic resonance response and the broaden distribution of electric field, our proposed structures perform a better tunability compared with traditional metamaterials loaded monolayer graphene. Since the dipole-dipole coupling between adjacent stacks strengthens immensely as reduces the filling factor of array, the modulated capacity could be further improved. It is found that for oblique incidence, the transmission property is also sensitive to the chemical potential of graphene as well as the polarization direction of incident terahertz wave. These results could be very instructive for the potential applications in voltage-sensitive devices, tunable sensors and photovoltaic switches.

  19. A terahertz polarization insensitive dual band metamaterial absorber.

    Science.gov (United States)

    Ma, Yong; Chen, Qin; Grant, James; Saha, Shimul C; Khalid, A; Cumming, David R S

    2011-03-15

    Metamaterial absorbers have attracted considerable attention for applications in the terahertz range. In this Letter, we report the design, fabrication, and characterization of a terahertz dual band metamaterial absorber that shows two distinct absorption peaks with high absorption. By manipulating the periodic patterned structures as well as the dielectric layer thickness of the metal-dielectric-metal structure, significantly high absorption can be obtained at specific resonance frequencies. Finite-difference time-domain modeling is used to design the structure of the absorber. The fabricated devices have been characterized using a Fourier transform IR spectrometer. The experimental results show two distinct absorption peaks at 2.7 and 5.2 THz, which are in good agreement with the simulation. The absorption magnitudes at 2.7 and 5.2 THz are 0.68 and 0.74, respectively.

  20. Multi-Spectral Materials: Hybridisation of Optical Plasmonic Filters and a Terahertz Metamaterial Absorber

    OpenAIRE

    Mccrindle, Iain J.H.; Grant, James; Drysdale, Timothy D.; Cumming, David R. S.

    2014-01-01

    Multi-spectral materials, using hybridised plasmonic and metamaterial structures, can simultaneously exhibit unique resonant phenomena over several decades of wavelengths. A multi-spectral material that combines a plasmonic colour filter array and a terahertz metamaterial absorber into a single material is a promising prospect for a coaxial multi-spectral imager operating in the visible, near IR, and terahertz wavebands.

  1. Ultra-flexible polarization-insensitive multiband terahertz metamaterial absorber.

    Science.gov (United States)

    Chen, Xu; Fan, Wenhui

    2015-03-20

    A thin-flexible and polarization-insensitive multiband terahertz metamaterial absorber (MMA) has been investigated. Each unit cell of the MMA consists of two metallic structures, which include the top metal resonator ring and the bottom metal ground plane, separated by a thin-flexible dielectric spacer. Finite element simulation indicates that this MMA has three high absorption peaks in the terahertz region, with absorptivities of 89% at 0.72 THz, 98% at 1.4 THz, and 85% at 2.3 THz. However, because of its rotationally symmetric structure, this MMA is polarization-insensitive and can perform very well at a wide range of incident angles, namely, 30° for transverse electric waves and 40° for transverse magnetic waves. The thin-flexible device structure and good performance shows that this MMA is very promising to disguise objects and make them less detectable to radar in the terahertz region.

  2. Terahertz bandwidth optical nonlinearity of graphene metamaterial

    OpenAIRE

    Nikolaenko, A.E.; Atmatzakis, E.; Papasimakis, N.; Luo, Z.; Shen, Z.X.; Boden, S.A.; Ashburn, P.; Zheludev, N.I.

    2012-01-01

    We provide the first observation that hybridizing graphene with plasmonic metamaterial results in order of magnitude resonant enhancement of its nonlinear optical properties and enables THz-bandwidth optical switching at near-infrared wavelengths.

  3. Switching terahertz waves with gate-controlled active graphene metamaterials.

    Science.gov (United States)

    Lee, Seung Hoon; Choi, Muhan; Kim, Teun-Teun; Lee, Seungwoo; Liu, Ming; Yin, Xiaobo; Choi, Hong Kyw; Lee, Seung S; Choi, Choon-Gi; Choi, Sung-Yool; Zhang, Xiang; Min, Bumki

    2012-11-01

    The extraordinary electronic properties of graphene provided the main thrusts for the rapid advance of graphene electronics. In photonics, the gate-controllable electronic properties of graphene provide a route to efficiently manipulate the interaction of photons with graphene, which has recently sparked keen interest in graphene plasmonics. However, the electro-optic tuning capability of unpatterned graphene alone is still not strong enough for practical optoelectronic applications owing to its non-resonant Drude-like behaviour. Here, we demonstrate that substantial gate-induced persistent switching and linear modulation of terahertz waves can be achieved in a two-dimensional metamaterial, into which an atomically thin, gated two-dimensional graphene layer is integrated. The gate-controllable light-matter interaction in the graphene layer can be greatly enhanced by the strong resonances of the metamaterial. Although the thickness of the embedded single-layer graphene is more than six orders of magnitude smaller than the wavelength (metamaterial, can modulate both the amplitude of the transmitted wave by up to 47% and its phase by 32.2° at room temperature. More interestingly, the gate-controlled active graphene metamaterials show hysteretic behaviour in the transmission of terahertz waves, which is indicative of persistent photonic memory effects.

  4. Performance of terahertz metamaterials as high-sensitivity sensor

    Science.gov (United States)

    He, Yanan; Zhang, Bo; Shen, Jingling

    2017-09-01

    A high-sensitivity sensor based on the resonant transmission characteristics of terahertz (THz) metamaterials was investigated, with the proposal and fabrication of rectangular bar arrays of THz metamaterials exhibiting a period of 180 μm on a 25 μm thick flexible polyimide. Varying the size of the metamaterial structure revealed that the length of the rectangular unit modulated the resonant frequency, which was verified by both experiment and simulation. The sensing characteristics upon varying the surrounding media in the sample were tested by simulation and experiment. Changing the surrounding medium from that of air to that of alcohol or oil produced resonant frequency redshifts of 80 GHz or 150 GHz, respectively, which indicates that the sensor possessed a high sensitivity of 667 GHz per unit of refractive index. Finally, the influence of the sample substrate thickness on the sensor sensitivity was investigated by simulation. It may be a reference for future sensor design.

  5. Nonlinear terahertz devices utilizing semiconducting plasmonic metamaterials

    OpenAIRE

    Seren, Huseyin R.; Zhang, Jingdi; Keiser, George R.; Maddox, Scott J.; Zhao, Xiaoguang; Fan, Kebin; Bank, Seth R.; Zhang, Xin; Averitt, Richard D.

    2015-01-01

    The development of responsive metamaterials has enabled the realization of compact tunable photonic devices capable of manipulating the amplitude, polarization, wave vector, and frequency of light. Integration of semiconductors into the active regions of metallic resonators is a proven approach for creating nonlinear metamaterials through optoelectronic control of the semiconductor carrier density. Metal-free subwavelength resonant semiconductor structures offer an alternative approach to cre...

  6. Dynamic metamaterial based on the graphene split ring high-Q Fano-resonnator for sensing applications.

    Science.gov (United States)

    Tang, Weiwei; Wang, Lin; Chen, Xiaoshuang; Liu, Changlong; Yu, Anqi; Lu, Wei

    2016-08-18

    Structured plasmonic metamaterials offer a new way to design functionalized optical and electrical components, since they can be size-scaled for operation across the whole electromagnetic spectrum. Here, we theoretically investigated electrical active split ring resonators based on graphene metamaterials on a SiO2/Si substrate that shows tunable frequency and amplitude modulation. For the symmetrical structure, the modulation depth of the frequency and amplitude can reach 58.58% and 99.35%, and 59.53% and 97.7% respectively in the two crossed-polarization orientations. Once asymmetry is introduced in the structure, the higher order mode which is inaccessible in the symmetrical structure can be excited, and a strong interaction among the modes in the split ring resonator forms a transparency window in the absorption band of the dipole resonance. Such metamaterials could facilitate the design of active modulation, and slow light effect for terahertz waves. Potential outcomes such as higher sensing abilities and higher-Q resonances at terahertz frequencies are demonstrated through numerical simulations with realistic parameters.

  7. [Research progress in the application of biosensors by using metamaterial in terahertz wave].

    Science.gov (United States)

    Yan, Xin; Zhang, Xing-Fang; Liang, Lan-Ju; Yao, Jian-Quan

    2014-09-01

    In the present paper, the recent progress in terahertz metamaterials-based sensing is reviewed with the principle of metamaterial biosensor,metamaterial substrate, and structure design, respectively. The paper introduces the principle in detail, analyzes the sensitivity of the biosensor with the material and the thickness of the substrate and the structure of metamaterial. The analysis shows that we can enhance the sensitivity and resolution of biosensor by designing specific metamaterial structure, using low dielectric constant and low loss thin substrate, especially many materials have a specific response in the terahertz frequency. So, there is a large potential application for label-free sensing by using the terahertz metamaterials. This paper also presents the future development of THz metamaterial sensors.

  8. Ultrasensitive terahertz metamaterial sensor based on spoof surface plasmon.

    Science.gov (United States)

    Chen, Xu; Fan, Wenhui

    2017-05-18

    A planar terahertz metamaterial sensor consisting of a corrugated metal stripe perforated by three rectangular grooves is proposed and investigated numerically. Due to the formation of Fabry-Perot resonance of the spoof surface plasmons mode on the corrugated metal stripe, the extremely sharp resonance in transmission spectrum associated with strong local field enhancement and high quality factor can be realized and exploited for ultrasensitive sensing. Since the intense interaction between electromagnetic waves and analyte materials, the frequency sensitivity of 1.966 THz per refractive index unit and the figure of merit of 19.86 can be achieved. Meanwhile, the film thickness sensitivity of this metamaterial sensor is higher than 52.5 GHz/μm when the analyte thickness is thinner than 4 μm. More interestingly, we find that the metal thickness has a great effect on the sensor performance. These findings open up opportunities for planar metamaterial structures to be developed into practical sensors in terahertz regime.

  9. A dual band terahertz metamaterial absorber

    Energy Technology Data Exchange (ETDEWEB)

    Tao Hu; Fan Kebin; Zhang Xin [Department of Mechanical Engineering, Boston University, Boston, MA 02215 (United States); Bingham, C M; Shrekenhamer, D; Padilla, W J [Department of Physics, Boston College, Chestnut Hill, MA 02467 (United States); Pilon, D; Strikwerda, A C; Averitt, R D, E-mail: xinz@bu.ed, E-mail: raveritt@physics.bu.ed [Department of Physics, Boston University, Boston, MA 02215 (United States)

    2010-06-09

    We present the design, fabrication and characterization of a dual band metamaterial absorber which experimentally shows two distinct absorption peaks of 0.85 at 1.4 THz and 0.94 at 3.0 THz. The dual band absorber consists of a dual band electric-field-coupled (ELC) resonator and a metallic ground plane, separated by an 8 {mu}m dielectric spacer. Fine tuning of the two absorption resonances is achieved by individually adjusting each ELC resonator geometry.

  10. Broadband terahertz metamaterial absorber based on sectional asymmetric structures

    Science.gov (United States)

    Gong, Cheng; Zhan, Mingzhou; Yang, Jing; Wang, Zhigang; Liu, Haitao; Zhao, Yuejin; Liu, Weiwei

    2016-01-01

    We suggest and demonstrate the concept and design of sectional asymmetric structures which can manipulate the metamaterial absorber’s working bandwidth with maintaining the other inherent advantages. As an example, a broadband terahertz perfect absorber is designed to confirm its effectiveness. The absorber’s each cell integrates four sectional asymmetric rings, and the entire structure composed of Au and Si3N4 is only 1.9 μm thick. The simulation results show the bandwidth with absorptivity being larger than 90% is extended by about 2.8 times comparing with the conventional square ring absorber. The composable small cell, ultra-thin, and broadband absorption with polarization and incident angle insensitivity will make the absorber suitable for the applications of focal plane array terahertz imaging. PMID:27571941

  11. Broadband terahertz metamaterial absorber based on sectional asymmetric structures.

    Science.gov (United States)

    Gong, Cheng; Zhan, Mingzhou; Yang, Jing; Wang, Zhigang; Liu, Haitao; Zhao, Yuejin; Liu, Weiwei

    2016-08-30

    We suggest and demonstrate the concept and design of sectional asymmetric structures which can manipulate the metamaterial absorber's working bandwidth with maintaining the other inherent advantages. As an example, a broadband terahertz perfect absorber is designed to confirm its effectiveness. The absorber's each cell integrates four sectional asymmetric rings, and the entire structure composed of Au and Si3N4 is only 1.9 μm thick. The simulation results show the bandwidth with absorptivity being larger than 90% is extended by about 2.8 times comparing with the conventional square ring absorber. The composable small cell, ultra-thin, and broadband absorption with polarization and incident angle insensitivity will make the absorber suitable for the applications of focal plane array terahertz imaging.

  12. Graphene-based tunable terahertz plasmon-induced transparency metamaterial.

    Science.gov (United States)

    Zhao, Xiaolei; Yuan, Cai; Zhu, Lin; Yao, Jianquan

    2016-08-18

    A novel terahertz plasmon induced transparency (PIT) metamaterial structure consisting of single-layered graphene microstructures was proposed and numerically studied in this study. A pronounced transparency peak was obtained in the transmission spectrum, which resulted from the destructive interference between the graphene dipole and monopole antennas. Further investigations have shown that the spectral location and lineshape of the transparency peak can be dynamically controlled by tuning the Fermi level in graphene. Since the monopole antennas in our designed structure exist in a continuous form, a more convenient method for tunablity is available by applying a gate voltage compared to those structures with discrete graphene patterns. This work may open up new avenues for designing tunable terahertz functional devices and slow light devices.

  13. Microelectromechanical systems bimaterial terahertz sensor with integrated metamaterial absorber.

    Science.gov (United States)

    Alves, Fabio; Grbovic, Dragoslav; Kearney, Brian; Karunasiri, Gamani

    2012-06-01

    This Letter describes the fabrication of a microelectromechanical systems (MEMS) bimaterial terahertz (THz) sensor operating at 3.8 THz. The incident THz radiation is absorbed by a metamaterial structure integrated with the bimaterial. The absorber was designed with a resonant frequency matching the quantum cascade laser illumination source while simultaneously providing structural support, desired thermomechanical properties and optical readout access. Measurement showed that the fabricated absorber has nearly 90% absorption at 3.8 THz. A responsivity of 0.1°/μW and a time constant of 14 ms were observed. The use of metamaterial absorbers allows for tuning the sensor response to the desired frequency to achieve high sensitivity for potential THz imaging applications.

  14. A kind of graphene film metamaterial for terahertz absorbers

    Science.gov (United States)

    Gao, Run-mei; Xu, Zong-cheng; Ding, Chun-feng; Yao, Jian-quan

    2016-01-01

    A kind of functional graphene thin film metamaterial on a metal-plane separated by a thick dielectric layer is designed for terahertz (THz) absorbers. We investigate the properties of the graphene metamaterial with different interlayers in the 0-3 THz range. The simulation results show that the absorption rate reaches up to 99.9% at the frequency of 1.917 THz. Changing the period to 80 μm×18 μm can get a narrow-band high quality factor ( Q) absorber. We present a novel theoretical interpretation based on the standing wave field theory, which shows that the coherent superposition of incident and reflection rays produces standing waves, and the field energy is localized inside the thick spacers and dissipates through the metal-planes.

  15. Study of the interaction between graphene and planar terahertz metamaterial with toroidal dipolar resonance.

    Science.gov (United States)

    Chen, Xu; Fan, Wenhui

    2017-05-15

    A planar terahertz metamaterial consisting of square split ring resonators is proposed, and the excitation of toroidal dipolar resonance is demonstrated. Moreover, we theoretically investigate the strong interaction between graphene and toroidal dipolar resonance of the metamaterial. By varying its Fermi energy, the simulations show that graphene can actively modulate the transmission amplitude of toroidal dipolar resonance and even switch it off. The interaction of the toroidal dipolar resonance with monolayer graphene further highlights the ultrasensitive sensing characteristic of the planar metamaterial, which can be utilized for other graphene-like two-dimensional materials. These intriguing properties of the proposed metamaterial may have potential applications in terahertz modulators and ultrasensitive sensors.

  16. Tunable metamaterial dual-band terahertz absorber

    Science.gov (United States)

    Luo, C. Y.; Li, Z. Z.; Guo, Z. H.; Yue, J.; Luo, Q.; Yao, G.; Ji, J.; Rao, Y. K.; Li, R. K.; Li, D.; Wang, H. X.; Yao, J. Q.; Ling, F. R.

    2015-11-01

    We report a design of a temperature controlled tunable dual band terahertz absorber. The compact single unit cell consists of two nested closed square ring resonators and a layer metallic separated by a substrate strontium titanate (STO) dielectric layer. It is found that the absorber has two distinctive absorption peaks at frequencies 0.096 THz and 0.137 THz, whose peaks are attained 97% and 75%. Cooling the absorber from 400 K to 250 K causes about 25% and 27% shift compared to the resonance frequency of room temperature, when we cooling the temperature to 150 K, we could attained both the two tunabilities exceeding 53%. The frequency tunability is owing to the variation of the dielectric constant of the low-temperature co-fired ceramic (LTCC) substrate. The mechanism of the dual band absorber is attributed to the overlapping of dual resonance frequencies, and could be demonstrated by the distributions of the electric field. The method opens up avenues for designing tunable terahertz devices in detection, imaging, and stealth technology.

  17. Tunable electromagnetically induced transparency from a superconducting terahertz metamaterial

    Science.gov (United States)

    Zhang, Caihong; Wu, Jingbo; Jin, Biaobing; Jia, Xiaoqing; Kang, Lin; Xu, Weiwei; Wang, Huabing; Chen, Jian; Tonouchi, Masoyoshi; Wu, Peiheng

    2017-06-01

    We demonstrate in this paper the tunable electromagnetically induced transparency (EIT) made from a superconducting (SC) niobium nitride (NbN) film induced by an intense terahertz (THz) field. As the variation of the incident THz field alters the intrinsic ohmic loss of the SC NbN film, the field-dependent transmittance is observed. To elaborate the role of the bright and dark modes, a hybrid coupling model is introduced to fit the experimental transmission spectra and extract the characteristic parameters of each mode. It is shown that the resonator for the bright mode is altered greatly due to strong direct coupling to the incident intense THz field, whereas the dark mode resonator has little interaction with the incident THz field via a weak near-filed coupling to the bright-mode resonator. This implies that we can partially control a mode or a part of metamaterial by introducing the intense THz field, which offers an effective manner to selectively control the electromagnetic property of the metamaterial. This work may bring many potential applications for the tunable EIT-like metamaterial.

  18. Tailoring the plasmon-induced transparency resonances in terahertz metamaterials.

    Science.gov (United States)

    Liu, Meng; Tian, Zhen; Zhang, Xueqian; Gu, Jianqiang; Ouyang, Chunmei; Han, Jiaguang; Zhang, Weili

    2017-08-21

    We experimentally demonstrate that a coupled metamaterial composed of sub-wavelength split-ring-resonators (SRRs) and closed-ring-resonators (CRRs) can tailor the plasmon-induced-transparency (PIT) resonances when the external electric field is parallel to the gaps of SRRs. Rotating or moving SRRs in vertical direction plays a critical role in the EIT functionality, while an excellent robust performance can be acquired via moving SRRs in the horizontal direction. Based on the results, a polarization-independent and polarization-dependent planar metamaterial are designed, fabricated and measured. In contrast to the spectral property of the polarization-independent medium, the polarization-dependent one is featured by isolated PIT phenomena in the frequency-domain, with respect to the horizontal and vertical polarized incident beam. Transmission responses of the PIT metamaterial are characterized with terahertz time-domain spectroscopy, showing a good agreement with the rigorous numerical simulation results. The presented work delivers a unique way to excite and modulate the PIT response, toward developing polarization-independent and polarization-dependent slow-light building blocks, ultrasensitive sensors and narrow-band filters functioning in the THz regime.

  19. Terahertz polarization converter based on all-dielectric high birefringence metamaterial with elliptical air holes

    KAUST Repository

    Zi, Jianchen

    2018-02-15

    Metamaterials have been widely applied in the polarization conversion of terahertz (THz) waves. However, common plasmonic metamaterials usually work as reflective devices and have low transmissions. All-dielectric metamaterials can overcome these shortcomings. An all-dielectric metamaterial based on silicon with elliptical air holes is reported to achieve high artificial birefringence at THz frequencies. Simulations show that with appropriate structural parameters the birefringence of the dielectric metamaterial can remain flat and is above 0.7 within a broad band. Moreover, the metamaterial can be designed as a broadband quarter wave plate. A sample metamaterial was fabricated and tested to prove the validity of the simulations, and the sample could work as a quarter wave plate at 1.76 THz. The all-dielectric metamaterial that we proposed is of great significance for high performance THz polarization converters.

  20. Terahertz chiral metamaterial based on twisted closed ring resonators

    Science.gov (United States)

    Stojanović, Danka B.; Beličev, Petra P.; Gligorić, Goran; Hadžievski, Ljupčo

    2018-01-01

    We present a chiral metamaterial (CMM) made of periodically distributed compact elements in a form of twisted closed ring resonators designed to be operational in terahertz (THz) frequency range. We analyze the three observed resonances in the absorption spectra and electric field distribution of linearly polarized incident electromagnetic waves. It has been shown that they arise due to excitation of symmetric and antisymmetric modes and are dependent on the geometry of resonant elements as well as the periodicity of the system. For the case of incident circularly polarized waves, a phenomenon of circular dichroism was observed, and its origin and dependency on the geometrical parameters and metal and dielectric losses was examined. This study indicates that the proposed CMM has a high potential for applications in the design of different THz components.

  1. Graphene-based tunable polarization sensitive terahertz metamaterial absorber

    Science.gov (United States)

    Deng, Guangsheng; Chen, Ping; Yang, Jun; Yin, Zhiping; Qiu, Longzhen

    2016-12-01

    A tunable metamaterial absorber composed of a metal ground plane, a SiO2 dielectric spacer, a graphene layer and a metal pattern layer, which is polarization sensitive is numerically proposed at terahertz (THz) frequencies. Our calculated results show that when the Fermi level of graphene is fixed at 0.7 eV, the absorptivities for x-polarized wave are about 0.985 at 6.42 THz, and 0.991 at 8.37 THz, respectively, while the absorptivity for y-polarized wave is about 0.99 at 7.22 THz. Moreover, the calculated electric field and surface current distributions, along with power loss distributions enable us to deeply understand the physical mechanism of resonance absorption. More importantly, absorption spectra at different Fermi levels of graphene and different incident angles are displayed and tuning functions are discussed in detail. This work may provide a further step in the development of potential applications based on metamaterial absorber, such as THz polarization imaging, THz sensing and polarization multiplexing.

  2. Broadband and high-efficient terahertz wave deflection based on C-shaped complex metamaterials with phase discontinuities

    KAUST Repository

    Tian, Zhen

    2013-09-01

    A terahertz metamaterial comprised of C-shaped SRRs was experimentally devised and demonstrated to exhibit high-efficient and broadband anomalous refraction with strong phase discontinuities. The generalized refraction properties of the proposed metamaterial, including the effect of various incident angles and polarizations were investigated at broad terahertz frequencies. By employing such metasurface, we demonstrated a simple method to tailor transmission and phase of terahertz wave. © 2013 IEEE.

  3. Enantiomeric switching of chiral metamaterial for terahertz polarization modulation employing vertically deformable MEMS spirals

    Science.gov (United States)

    Kan, Tetsuo; Isozaki, Akihiro; Kanda, Natsuki; Nemoto, Natsuki; Konishi, Kuniaki; Takahashi, Hidetoshi; Kuwata-Gonokami, Makoto; Matsumoto, Kiyoshi; Shimoyama, Isao

    2015-01-01

    Active modulation of the polarization states of terahertz light is indispensable for polarization-sensitive spectroscopy, having important applications such as non-contact Hall measurements, vibrational circular dichroism measurements and anisotropy imaging. In the terahertz region, the lack of a polarization modulator similar to a photoelastic modulator in the visible range hampers expansion of such spectroscopy. A terahertz chiral metamaterial has a huge optical activity unavailable in nature; nevertheless, its modulation is still challenging. Here we demonstrate a handedness-switchable chiral metamaterial for polarization modulation employing vertically deformable Micro Electro Mechanical Systems. Vertical deformation of a planar spiral by a pneumatic force creates a three-dimensional spiral. Enantiomeric switching is realized by selecting the deformation direction, where the polarity of the optical activity is altered while maintaining the spectral shape. A polarization rotation as high as 28° is experimentally observed, thus providing a practical and compact polarization modulator for the terahertz range. PMID:26423346

  4. Multi-spectral materials: hybridisation of optical plasmonic filters, a mid infrared metamaterial absorber and a terahertz metamaterial absorber.

    Science.gov (United States)

    Grant, James; McCrindle, Iain J H; Cumming, David R S

    2016-02-22

    Multi-spectral imaging systems typically require the cumbersome integration of disparate filtering materials and detectors in order to operate simultaneously in multiple spectral regions. Each distinct waveband must be detected at different spatial locations on a single chip or by separate chips optimised for each band. Here, we report on a single component that optically multiplexes visible, Mid Infrared (4.5 μm) and Terahertz (126 μm) radiation thereby maximising the spectral information density. We hybridise plasmonic and metamaterial structures to form a device capable of simultaneously filtering 15 visible wavelengths and absorbing Mid Infrared and Terahertz. Our synthetic multi-spectral component could be integrated with silicon complementary metal-oxide semiconductor technology where Si photodiodes are available to detect the visible radiation and micro-bolometers available to detect the Infrared/Terahertz and render an inexpensive, mass-producible camera capable of forming coaxial visible, Infrared and Terahertz images.

  5. Membrane metamaterial resonators with a sharp resonance: A comprehensive study towards practical terahertz filters and sensors

    Directory of Open Access Journals (Sweden)

    Yongyao Chen

    2012-06-01

    Full Text Available We investigate the resonant properties of high quality-factor membrane-based metamaterial resonators functioning in the terahertz regime. A number of factors, including the resonator geometry, dielectric loss, and most importantly the membrane thickness are found to extensively influence the resonance strength and quality factor of the sharp resonance. Further studies on the membrane thickness-dependent-sensitivity for sensing applications reveal that high quality-factor membrane metamaterials with a moderate thickness ranging from 10 to 50 μm are the most promising option towards developing realistic integrated terahertz filters and sensors.

  6. Voltage adjusting characteristics in terahertz transmission through Fabry-Pérot-based metamaterials

    Directory of Open Access Journals (Sweden)

    Jun Luo

    2015-10-01

    Full Text Available Metallic electric split-ring resonators (SRRs with featured size in micrometer scale, which are connected by thin metal wires, are patterned to form a periodically distributed planar array. The arrayed metallic SRRs are fabricated on an n-doped gallium arsenide (n-GaAs layer grown directly over a semi-insulating gallium arsenide (SI-GaAs wafer. The patterned metal microstructures and n-GaAs layer construct a Schottky diode, which can support an external voltage applied to modify the device properties. The developed architectures present typical functional metamaterial characters, and thus is proposed to reveal voltage adjusting characteristics in the transmission of terahertz waves at normal incidence. We also demonstrate the terahertz transmission characteristics of the voltage controlled Fabry-Pérot-based metamaterial device, which is composed of arrayed metallic SRRs. To date, many metamaterials developed in earlier works have been used to regulate the transmission amplitude or phase at specific frequencies in terahertz wavelength range, which are mainly dominated by the inductance-capacitance (LC resonance mechanism. However, in our work, the external voltage controlled metamaterial device is developed, and the extraordinary transmission regulation characteristics based on both the Fabry-Pérot (FP resonance and relatively weak surface plasmon polariton (SPP resonance in 0.025-1.5 THz range, are presented. Our research therefore shows a potential application of the dual-mode-resonance-based metamaterial for improving terahertz transmission regulation.

  7. Tunable terahertz absorption in graphene-based metamaterial

    Science.gov (United States)

    Zhang, Qinfei; Ma, Qixiang; Yan, Shitao; Wu, Fengmin; He, Xunjun; Jiang, Jiuxing

    2015-10-01

    One of the most important advantages of graphene is the capability of dynamically tuning its conductivity by means of chemical doping or gate voltage. Based on this property, we proposed a tunable graphene-based terahertz absorber composed of a periodically patterned graphene structure and a metal ground plane spaced by a thin SiO2 dielectric layer. Our calculated results show that a perfect absorption can be achieved by using a single layer of graphene-based metamaterial structure at a fixed Fermi energy level. Moreover, the calculated electric field and power loss distributions enable us to reveal the absorption mechanism of the designed absorber. More importantly, we found that the absorption peak can be dynamically controlled over a broadband frequency range by adjusting the gate voltage without re-optimizing or re-fabricating the physical structure. This work may provide a further step in the development of compact tunable devices, such as tunable sensors and absorbers, switches, and slow light devices.

  8. Characteristic analysis of a photoexcited metamaterial perfect absorber at terahertz frequencies

    Science.gov (United States)

    Bing, Pibin; Huang, Shichao; Li, Zhongyang; Yu, Zhou; Lu, Ying; Yao, Jianquan

    2017-06-01

    The absorption characteristics of a photoexcited metamaterial absorber at terahertz frequencies were analyzed in this study. Filling photosensitive semiconductor silicon into the gap between the resonator arms leads to modulation of its electromagnetic response through a pump beam which changes conductivity of silicon. Comparisons of terahertz absorbing properties which were caused by different thicknesses and dielectric constants of polyimide, cell sizes and widths of SRRs, and lengths and conductivities of the photosensitive silicon, were studied by using Finite Difference Time Domain (FDTD) from 0.4 THz to 1.6 THz. The results of this study will facilitate the design and preparation of terahertz modulator, filters and absorbers.

  9. Uncooled CMOS terahertz imager using a metamaterial absorber and pn diode.

    Science.gov (United States)

    Escorcia, Ivonne; Grant, James; Gough, John; Cumming, David R S

    2016-07-15

    We demonstrate a low-cost uncooled terahertz (THz) imager fabricated in a standard 180 nm CMOS process. The imager is composed of a broadband THz metamaterial absorber coupled with a diode microbolometer sensor where the pn junction is used as a temperature sensitive device. The metamaterial absorber array is integrated in the top metallic layers of a six metal layer process allowing for complete monolithic integration of the metamaterial absorber and sensor. We demonstrate the capability of the detector for stand-off imaging applications by using it to form transmission and reflection images of a metallic object hidden in a manila envelope.

  10. Metamaterials on parylene thin film substrates: Design, fabrication, and characterization at terahertz frequency

    Science.gov (United States)

    Liu, X.; MacNaughton, S.; Shrekenhamer, D. B.; Tao, H.; Selvarasah, S.; Totachawattana, A.; Averitt, R. D.; Dokmeci, M. R.; Sonkusale, S.; Padilla, W. J.

    2010-01-01

    We design, fabricate, and characterize terahertz (THz) resonant metamaterials on parylene free-standing thin film substrates. Several different metamaterials are investigated and our results show strong electromagnetic responses at THz frequencies ranging from 500 GHz to 2.5 THz. The complex frequency dependent dielectric properties of parylene are determined from inversion of reflection and transmission data, thus indicating that parylene is an ideal low loss substrate or coating material. The biostable and biocompatible properties of parylene coupled with the multifunctional exotic properties of metamaterials indicate great potential for medical purposes such as THz imaging for skin cancer detection.

  11. Controlling terahertz waves with meta-materials and photonic bandgap structures

    Energy Technology Data Exchange (ETDEWEB)

    Shchegolkov, Dmitry [Los Alamos National Laboratory; Azad, Abul [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Moody, Nathan A [Los Alamos National Laboratory; Simakov, Evgenya I [Los Alamos National Laboratory

    2010-12-07

    We will describe research conducted at Los Alamos National Laboratory towards developing components for controlling terahertz waves. We employ meta-materials and, particularly, meta-films, as very compact absorbers for controlling quasioptical beams. We believe that dielectric photonic bandgap structures could replace ordinary metal waveguide devices at THz, since metal structures become extremely lossy in this frequency range.

  12. Subluminal and superluminal terahertz radiation in metamaterials with electromagnetically induced transparency.

    Science.gov (United States)

    Bai, Zhengyang; Hang, Chao; Huang, Guoxiang

    2013-07-29

    We propose a scheme to design a new type of optical metamaterial that can mimic the functionality of four-state atomic systems of N-type energy-level configuration with electromagnetically induced transparency (EIT). We show that in such metamaterial a transition from a single EIT to a double EIT of terahertz radiation may be easily achieved by actively tuning the intensity of the infrared pump field or passively tuning the geometrical parameters of resonator structures. In addition, the group velocity of the terahertz radiation can be varied from subluminal to superluminal by changing the pump field intensity. The scheme suggested here may be used to construct chip-scale slow and fast light devices and to realize rapidly responded switching of terahertz radiation at room temperature.

  13. Design and analysis of perfect terahertz metamaterial absorber by a novel dynamic circuit model.

    Science.gov (United States)

    Hokmabadi, Mohammad Parvinnezhad; Wilbert, David S; Kung, Patrick; Kim, Seongsin M

    2013-07-15

    Metamaterial terahertz absorbers composed of a frequency selective layer followed by a spacer and a metallic backplane have recently attracted great attention as a device to detect terahertz radiation. In this work, we present a quasistatic dynamic circuit model that can decently describe operational principle of metamaterial terahertz absorbers based on interference theory of reflected waves. The model comprises two series LC resonance components, one for resonance in frequency selective surface (FSS) and another for resonance inside the spacer. Absorption frequency is dominantly determined by the LC of FSS while the spacer LC changes slightly the magnitude and frequency of absorption. This model fits perfectly for both simulated and experimental data. By using this model, we study our designed absorber and we analyze the effect of changing in spacer thickness and metal conductivity on absorption spectrum.

  14. Experimental demonstration of ultrasensitive sensing with terahertz metamaterial absorbers: A comparison with the metasurfaces

    Energy Technology Data Exchange (ETDEWEB)

    Cong, Longqing; Singh, Ranjan, E-mail: ranjans@ntu.edu.sg [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Tan, Siyu [School of Electrical Engineering and Computer Science, Oklahoma State University, Stillwater, Oklahoma 87074 (United States); Key Lab of All Optical Network and Advanced Telecommunication Network of EMC, Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044 (China); Yahiaoui, Riad [XLIM, Limoges University, CNRS, UMR 7252, 7 rue Jules Vallès, F-19100 Brive (France); Yan, Fengping [Key Lab of All Optical Network and Advanced Telecommunication Network of EMC, Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Weili [School of Electrical Engineering and Computer Science, Oklahoma State University, Stillwater, Oklahoma 87074 (United States)

    2015-01-19

    Planar metasurfaces and plasmonic resonators have shown great promise for sensing applications across the electromagnetic domain ranging from the microwaves to the optical frequencies. However, these sensors suffer from lower figure of merit and sensitivity due to the radiative and the non-radiative loss channels in the plasmonic metamaterial systems. We demonstrate a metamaterial absorber based ultrasensitive sensing scheme at the terahertz frequencies with significantly enhanced sensitivity and an order of magnitude higher figure of merit compared to planar metasurfaces. Magnetic and electric resonant field enhancement in the impedance matched absorber cavity enables stronger interaction with the dielectric analyte. This finding opens up opportunities for perfect metamaterial absorbers to be applied as efficient sensors in the finger print region of the electromagnetic spectrum with several organic, explosive, and bio-molecules that have unique spectral signature at the terahertz frequencies.

  15. Experimental demonstration of ultrasensitive sensing with terahertz metamaterial absorbers: A comparison with the metasurfaces

    Science.gov (United States)

    Cong, Longqing; Tan, Siyu; Yahiaoui, Riad; Yan, Fengping; Zhang, Weili; Singh, Ranjan

    2015-01-01

    Planar metasurfaces and plasmonic resonators have shown great promise for sensing applications across the electromagnetic domain ranging from the microwaves to the optical frequencies. However, these sensors suffer from lower figure of merit and sensitivity due to the radiative and the non-radiative loss channels in the plasmonic metamaterial systems. We demonstrate a metamaterial absorber based ultrasensitive sensing scheme at the terahertz frequencies with significantly enhanced sensitivity and an order of magnitude higher figure of merit compared to planar metasurfaces. Magnetic and electric resonant field enhancement in the impedance matched absorber cavity enables stronger interaction with the dielectric analyte. This finding opens up opportunities for perfect metamaterial absorbers to be applied as efficient sensors in the finger print region of the electromagnetic spectrum with several organic, explosive, and bio-molecules that have unique spectral signature at the terahertz frequencies.

  16. Towards loss compensated and lasing terahertz metamaterials based on optically pumped graphene.

    Science.gov (United States)

    Weis, P; Garcia-Pomar, J L; Rahm, M

    2014-04-07

    We evidence by numerical calculations that optically pumped graphene is suitable for compensating inherent loss in terahertz (THz) metamaterials. We calculate the complex conductivity of graphene under optical pumping and determine the proper conditions for terahertz amplification in single layer graphene. It is shown that amplification in graphene occurs up to room temperature for moderate pump intensities at telecommunication wavelength λ = 1.5 μm. Furthermore, we investigate the coupling between a plasmonic split ring resonator (SRR) metamaterial and optically pumped graphene at a temperature T = 77 K and a pump intensity I = 300 mW/mm(2). We find that the loss of a SRR metamaterial can be compensated by optically stimulated amplification in graphene. Moreover, we show that a hybrid material consisting of asymmetric split-ring resonators and optically pumped graphene can emit coherent THz radiation at minimum output power levels of 60 nW/mm(2).

  17. Transmission and reflection properties of terahertz fractal metamaterials

    DEFF Research Database (Denmark)

    Malureanu, Radu; Lavrinenko, Andrei; Cooke, David

    2010-01-01

    We use THz time-domain spectroscopy to investigate transmission and reflection properties of metallic fractal metamaterial structures. We observe loss of free-space energy at certain resonance frequencies, indicating excitation of surface modes of the metamaterial....

  18. Generation of high-power terahertz radiation by nonlinear photon-assisted tunneling transport in plasmonic metamaterials

    Science.gov (United States)

    Chen, Pai-Yen; Salas, Rodolfo; Farhat, Mohamed

    2017-12-01

    We propose an optoelectronic terahertz oscillator based on the quantum tunneling effect in a plasmonic metamaterial, utilizing a nanostructured metal-insulator-metal (MIM) tunneling junction. The collective resonant response of meta-atoms can achieve >90% optical absorption and strongly localized optical fields within the MIM plasmonic nanojunction. By properly tailoring the radiation aperture, the nonlinear quantum conductance induced by the metamaterial-enhanced, photon-assisted tunneling may produce miliwatt-level terahertz radiation through the optical beating (or heterodyne down conversion) of two lasers with a slight frequency offset. We envisage that the interplay between photon-assisted tunneling and plasmon coupling within the MIM metamaterial/diode may substantially enhance the modulated terahertz photocurrent, and may therefore realize a practical high-power, room-temperature source in applications of terahertz electronics.

  19. Optically active Babinet planar metamaterial film for terahertz polarization manipulation

    DEFF Research Database (Denmark)

    Zalkovskij, Maksim; Malureanu, Radu; Kremers, C.

    2013-01-01

    A planar Babinet-inverted dimer metamaterial possessing strong optical activity is proposed and characterized. An original fabrication method to produce large area (up to several cm2) freely suspended flexible metallic membranes is implemented to fabricate the metamaterial. Its optical properties...

  20. Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach.

    Science.gov (United States)

    Andryieuski, Andrei; Lavrinenko, Andrei V

    2013-04-08

    In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers.

  1. Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Lavrinenko, Andrei

    2013-01-01

    In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity...... we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers....

  2. Optically and thermally controlled terahertz metamaterial via transition between direct and indirect electromagnetically induced transparency

    Directory of Open Access Journals (Sweden)

    Jiawei Sui

    2014-12-01

    Full Text Available This passage presents a design of tunable terahertz metamaterials via transition between indirect and direct electromagnetically induced transparency (EIT effects by changing semiconductor InSb’s properties to terahertz wave under optical and thermal stimuli. Mechanical model and its electrical circuit model are utilized in analytically calculating maximum transmission of transparency window. Simulated results show consistency with the analytical expressions. The results show that the metamaterials hold 98.4% modulation depth at 189 GHz between 300 K, σInSb =256000 S/m, and 80 K, σInSb =0.0162 S/m conditions , 1360 ps recovery time of the excited electrons in InSb under optical stimulus at 300 K mainly considering the direct EIT effect, and minimum bandwidth 1 GHz.

  3. Ultra-broadband and polarization-insensitive wide-angle terahertz metamaterial absorber

    Science.gov (United States)

    Li, Xinwang; Liu, Hongjun; Sun, Qibing; Huang, Nan

    2015-06-01

    In this paper, an ultra-broadband and polarization insensitive terahertz (THz) metamaterial absorber is presented and investigated. With the optimization of the structural parameters, resonant peaks are merged into a broadband absorption spectrum. The simulation results demonstrate that a wide bandwidth of 3.1 THz is obtained in the range from 2.6 to 5.7 THz, where the absorption is higher than 90% for the normal incident THz waves. The full width at half maximum (FWHM) of absorption spectrum is 95% with respect to central frequency (∼4 THz), which is five times greater than the FWHM of a single layer structure. Furthermore, this structure can keep the absorption above 88% over a large frequency range (>2.5 THz) when the incident angle is smaller than 50°. This metamaterial absorber can find potential applications in terahertz imaging and stealth technology.

  4. A novel graphene metamaterial design for tunable terahertz plasmon induced transparency by two bright mode coupling

    Science.gov (United States)

    Zhang, Huiyun; Cao, Yanyan; Liu, Yuanzhong; Li, Yue; Zhang, Yuping

    2017-05-01

    A novel graphene-based metamaterial for terahertz plasmon induced transparency (PIT) is presented in this paper, which consists of a graphene ring and a graphene strip compound structure. Both the ring and strip are performed as bright modes which are induced by electric dipole resonances, respectively. The weak hybridization between two elements leads to a novel PIT window. The PIT window can be controlled by adjusting the geometric parameters of graphene-based metamaterial structure. More importantly, the resonant frequency of transparency window can be dynamically tuned over a broad frequency range by varying the Fermi energy of graphene through controlling the electrostatic gating instead of refabricating the structures. Correspondingly, through adjusting the Fermi energy of graphene, a large group delay could also be observed, reaching up to 0.5 ps at the transparent peak. These results may offer great promise for tunable terahertz switching, slow light device, and sensing technology.

  5. Enhanced circular dichroism based on the dual-chiral metamaterial in terahertz regime

    Science.gov (United States)

    Jian, Shao; Jie, Li; Ying-Hua, Wang; Jia-Qi, Li; Zheng-Gao, Dong; Lin, Zhou

    2016-05-01

    The obvious circular dichroism (CD) and optical activity can be obtained based on the chiral metamaterial due to the plasmon-enhanced effect, which is very attractive for future compact devices with enhanced capabilities of light manipulation. In this paper, we propose a dual-chiral metamaterial composed of bilayer asymmetric split ring resonators (ASRR) that are in mirror-symmetry shape. It is demonstrated that the CD can get enhancement in the terahertz regime. Moreover, the CD can be further improved by modulating the asymmetry of ASRR. The enhanced CD effect in the terahertz regime has great potential applications in sensing, biomedical imaging, and molecular recognition. Project supported by the National Natural Science Foundation of China (Grant Nos. 11174051, 11374049, and 11204139), the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20131283), and the Fundamental Research Funds for the Central Universities, China.

  6. Low-bias active control of terahertz waves by coupling large-area CVD graphene to a terahertz metamaterial.

    Science.gov (United States)

    Valmorra, Federico; Scalari, Giacomo; Maissen, Curdin; Fu, Wangyang; Schönenberger, Christian; Choi, Jong Won; Park, Hyung Gyu; Beck, Mattias; Faist, Jérôme

    2013-07-10

    We propose an hybrid graphene/metamaterial device based on terahertz electronic split-ring resonators directly evaporated on top of a large-area single-layer CVD graphene. Room temperature time-domain spectroscopy measurements in the frequency range from 250 GHz to 2.75 THz show that the presence of the graphene strongly changes the THz metamaterial transmittance on the whole frequency range. The graphene gating allows active control of such interaction, showing a modulation depth of 11.5% with an applied bias of 10.6 V. Analytical modeling of the device provides a very good qualitative and quantitative agreement with the measured device behavior. The presented system shows potential as a THz modulator and can be relevant for strong light-matter coupling experiments.

  7. External amplitude and frequency modulation of a terahertz quantum cascade laser using metamaterial/graphene devices.

    Science.gov (United States)

    Kindness, S J; Jessop, D S; Wei, B; Wallis, R; Kamboj, V S; Xiao, L; Ren, Y; Braeuninger-Weimer, P; Aria, A I; Hofmann, S; Beere, H E; Ritchie, D A; Degl'Innocenti, R

    2017-08-09

    Active control of the amplitude and frequency of terahertz sources is an essential prerequisite for exploiting a myriad of terahertz applications in imaging, spectroscopy, and communications. Here we present a optoelectronic, external modulation technique applied to a terahertz quantum cascade laser which holds the promise of addressing a number of important challenges in this research area. A hybrid metamaterial/graphene device is implemented into an external cavity set-up allowing for optoelectronic tuning of feedback into a quantum cascade laser. We demonstrate powerful, all-electronic, control over the amplitude and frequency of the laser output. Full laser switching is performed by electrostatic gating of the metamaterial/graphene device, demonstrating a modulation depth of 100%. External control of the emission spectrum is also achieved, highlighting the flexibility of this feedback method. By taking advantage of the frequency dispersive reflectivity of the metamaterial array, different modes of the QCL output are selectively suppressed using lithographic tuning and single mode operation of the multi-mode laser is enforced. Side mode suppression is electrically modulated from ~6 dB to ~21 dB, demonstrating active, optoelectronic modulation of the laser frequency content between multi-mode and single mode operation.

  8. Anti-reflection coating design for metallic terahertz meta-materials

    Science.gov (United States)

    Pancaldi, Matteo; Freeman, Ryan; Hudl, Matthias; Hoffmann, Matthias C.; Urazhdin, Sergei; Vavassori, Paolo; Bonetti, Stefano

    2018-02-01

    We demonstrate a silicon-based, single-layer anti-reflection coating that suppresses the reflectivity of metals at near-infrared frequencies, enabling optical probing of nano-scale structures embedded in highly reflective surroundings. Our design does not affect the interaction of terahertz radiation with metallic structures that can be used to achieve terahertz near-field enhancement. We have verified the functionality of the design by calculating and measuring the reflectivity of both infrared and terahertz radiation from a silicon/gold double layer as a function of the silicon thickness. We have also fabricated the unit cell of a terahertz meta-material, a dipole antenna comprising two 20-nm thick extended gold plates separated by a 2 $\\mu$m gap, where the terahertz field is locally enhanced. We used the time-domain finite element method to demonstrate that such near-field enhancement is preserved in the presence of the anti-reflection coating. Finally, we performed magneto-optical Kerr effect measurements on a single 3-nm thick, 1-$\\mu$m wide magnetic wire placed in the gap of such a dipole antenna. The wire only occupies 2\\% of the area probed by the laser beam, but its magneto-optical response can be clearly detected. Our design paves the way for ultrafast time-resolved studies, using table-top femtosecond near-infrared lasers, of dynamics in nano-structures driven by strong terahertz radiation.

  9. A Brief Review on Metamaterial-Based Vacuum Electronics for Terahertz and Microwave Science and Technology

    Science.gov (United States)

    Matsui, Tatsunosuke

    2017-09-01

    Metamaterials, which enable us to realize novel physical effects that cannot be achieved using natural materials, have been extensively studied in recent years and significant progress has been made, especially in the field of optics. This game-changing concept has also initiated a rich variety of research activity in vacuum electronics. Here we review the recent development of metamaterial-based vacuum electronics for terahertz (THz) and microwave science and technology. The reversed Cherenkov radiation (RCR) in double-negative (DNG) metamaterials predicted by Veselago back in the 1960s has been experimentally verified in the microwave frequency range by utilizing specially designed DNG metamaterials. The interaction of an electron beam (e-beam) with DNG metamaterials may lead to the realization of novel applications such as microwave and THz radiation sources, accelerators, and even the visualization of invisibility cloaks. Smith-Purcell radiation (SPR) has recently received renewed interest owing to the development of metamaterials and the concept of spoof surface plasmon polaritons, as discussed in this review, and recent results on e-beam-induced directional and wide-band THz radiation with sharp multiple peaks from a graded grating, as well as directional and monochromatic special SPR and their possible application to THz orotron devices, are also reviewed.

  10. Graphene based metamaterials for terahertz cloaking and subwavelength imaging

    Science.gov (United States)

    Forouzmand, Seyedali

    Graphene is a two-dimensional carbon crystal that became one of the most controversial topics of research in the last few years. The intense interest in graphene stems from recent demonstrations of their potentially revolutionary electromagnetic applications -- including negative refraction, subdiffraction imaging, and even invisibility -- which have suggested a wide range of new devices for communications, sensing, and biomedicine. In addition, it has been shown that graphene is amenable to unique patterning schemes such as cutting, bending, folding, and fusion that are predicted to lead to interesting properties. A recent proposed application of graphene is in engineering the scattering properties of objects, which may be leveraged in applications such as radar-cross-section management and stealth, where it may be required to make one object look like another object or render an object completely invisible. We present the analytical formulation for the analysis of electromagnetic interaction with a finite conducting wedge covered with a cylindrically shaped nanostructured graphene metasurface, resulting in the scattering cancellation of the dominant scattering mode for all the incident and all the observation angles. Following this idea, the cylindrical graphene metasurface is utilized for cloaking of several concentric finite conducting wedges. In addition, a wedge shaped metasurface is proposed as an alternative approach for cloaking of finite wedges. The resolution of the conventional imaging lenses is restricted by the natural diffraction limit. Artificially engineered metamaterials now offer the possibility of creating a superlens that overcomes this restriction. We demonstrate that a wire medium (WM) slab loaded with graphene sheets enables the enhancement of the near field for subwavelength imaging at terahertz (THz) frequencies. The analysis is based on the nonlocal homogenization model for WM with the additional boundary condition in the connection of

  11. Mode coupling in terahertz metamaterials using sub-radiative and super-radiative resonators

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Shen; Zhang, Yaxin, E-mail: Zhangyaxin@uestc.edu.cn; Zhao, Yuncheng; Xu, Gaiqi; Sun, Han; Yang, Ziqiang [Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054 (China); Liang, Shixiong [National Key Laboratory of Application Specific Integrated Circuit, Hebei Semiconductor Research Institute, Shijiazhuang 050051 (China)

    2015-11-21

    We theoretically and experimentally explored the electromagnetically induced transparency (EIT) mode-coupling in terahertz (THz) metamaterial resonators, in which a dipole resonator with a super-radiative mode is coupled to an inductance-capacitance resonator with a sub-radiative mode. The interference between these two resonators depends on the relative spacing between them, resulting in a tunable transparency window in the absorption spectrum. Mode coupling was experimentally demonstrated for three spacing dependent EIT metamaterials. Transmittance of the transparency windows could be either enhanced or suppressed, producing different spectral linewidths. These spacing dependent mode-coupling metamaterials provide alternative ways to create THz devices, such as filters, absorbers, modulators, sensors, and slow-light devices.

  12. Metamaterial composite bandpass filter with an ultra-broadband rejection bandwidth of up to 240 terahertz

    DEFF Research Database (Denmark)

    Strikwerda, Andrew; Zalkovskij, Maksim; Lorenzen, Dennis Lund

    2014-01-01

    We present a metamaterial, consisting of a cross structure and a metal mesh filter, that forms a composite with greater functional bandwidth than any terahertz (THz) metamaterial to date. Metamaterials traditionally have a narrow usable bandwidth that is much smaller than common THz sources......, such as photoconductive antennas and difference frequency generation. The composite structure shown here expands the usable bandwidth to exceed that of current THz sources. To highlight the applicability of this combination, we demonstrate a series of bandpass filters with only a single pass band, with a central...... frequency (f) that is scalable from 0.86–8.51 THz, that highly extinguishes other frequencies up to >240 THz. The performance of these filters is demonstrated in experiment, using both air biased coherent detection and a Fourier transform infrared spectrometer (FTIR), as well as in simulation. We present...

  13. Electrically tunable terahertz wave modulator based on complementary metamaterial and graphene

    Energy Technology Data Exchange (ETDEWEB)

    He, Xun-jun, E-mail: hexunjun@hrbust.edu.cn; Li, Teng-yue; Wang, Lei; Wang, Jian-min; Jiang, Jiu-xing [Department of Electronic Science and technology, School of Applied Sciences, Harbin University of Science and Technology, Harbin 150080 (China); Yang, Guo-hui; Meng, Fan-yi; Wu, Qun [Department of Electronic and Communications Engineering, School of Electronic Information Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2014-05-07

    In this paper, we design and numerically demonstrate an electrically controllable light-matter interaction in a hybrid material/metamaterial system consisting of an artificially constructed cross cut-wire complementary metamaterial and an atomically thin graphene layer to realize terahertz (THz) wave modulator. By applying a bias voltage between the metamaterial and the graphene layer, this modulator can dynamically control the amplitude and phase of the transmitted wave near 1.43 THz. Moreover, the distributions of current density show that this large modulation depth can be attributed to the resonant electric field parallel to the graphene sheet. Therefore, the modulator performance indicates the enormous potential of graphene for developing sophisticated THz communication systems.

  14. Terahertz metamaterial based on dual-band graphene ring resonator for modulating and sensing applications

    Science.gov (United States)

    Liu, Chenxi; Liu, Peiguo; Yang, Cheng; Bian, Lian

    2017-11-01

    A new design of terahertz (THz) metamaterial is proposed for modulating and sensing purposes. The metamaterial consists of two resonators based on periodical arrays of graphene rings with different radii. For each small ring, it is surrounded by four large rings, and vice versa. By varying the Fermi level through electrostatically gating, the transmission of the graphene metamaterial can be controlled dynamically and the maximum modulation depths can reach up to 86% and 73%. Especially, an electromagnetically induced transparency (EIT)-like phenomenon can be generated, which results from the weak hybridization between two nearest neighbor rings performed as bright modes induced by electric dipole. Consequently, frequency sensitivity of 830 GHz per refractive index unit and figure-of-merit of 17 can be realized at the transparency peak. Our work offers an additional opportunity to achieve an EIT-like effect and potential applications in designing active THz modulators and sensors.

  15. Flexible metamaterial absorbers for stealth applications at terahertz frequencies

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Strikwerda, Andrew; Fan, K.

    2012-01-01

    We have wrapped metallic cylinders with strongly absorbing metamaterials. These resonant structures, which are patterned on flexible substrates, smoothly coat the cylinder and give it an electromagnetic response designed to minimize its radar cross section. We compare the normal-incidence, small...... frequency of 0.87 THz. In addition we discuss the effect of finite sample dimensions and the spatial dependence of the reflection spectrum of the metamaterial. (C)2011 Optical Society of America...

  16. Detection of terahertz radiation in metamaterials: giant plasmonic ratchet effect (Conference Presentation)

    Science.gov (United States)

    Rudin, Sergey; Rupper, Greg; Kachorovski, Valentin; Shur, Michael S.

    2017-05-01

    The electromagnetic wave impinging on the spatially modulated two-dimensional electron liquid (2DEL) induces a direct current (DC) when the wave amplitude modulated with the same wave vector as the 2DEL but is shifted in phase (the ratchet effect). The recent theory of this phenomenon predicted a dramatic enhancement at the plasmonic resonances and a non-trivial polarization dependence [1]. We will present the results of the numerical simulations using a hydrodynamic model exploring the helicity dependence of the DC current for silicon, InGaAs, and GaN metamaterial structures at cryogenic and room temperatures. In particular we will report on the effect of the DEL viscosity and explore the nonlinear effects at large amplitudes of the helical electromagnetic radiation impinging on the ratchet structures. We will then discuss the applications of the ratchet effect for terahertz metamaterials in order to realize ultra-sensitive terahertz (THz) radiation detectors, modulators, phase shifters, and delay lines with cross sections matching the terahertz wavelength and capable of determining the electromagnetic wave polarization and helicity. To this end, we propose and analyze the four contact ratchet devices capable of registering the two perpendicular components of the electric currents induced by the elliptically or circularly polarized radiation and analyze the load impedance effects in the structures optimized for the ratchet metamaterial THz components. The analysis is based on the hydrodynamic model suitable for the multi-gated semiconductor structures, coupled self-consistently with Poisson's equation for the electric potential. The model accounts for the effects of pressure gradients and 2DEL viscosity. Our numerical solutions are applicable to the wide ranges of electron mobility and terahertz power. [1] I. V. Rozhansky, V. Yu. Kachorovskii, and M. S. Shur, Helicity-Driven Ratchet Effect Enhanced by Plasmons, Phys. Rev. Lett. 114, 246601, 15 June 2015

  17. Studies on the resonant properties in the asymmetric dipole-array terahertz metamaterials

    Science.gov (United States)

    Chen, Wei; Zhou, Qingli; Li, Chenyu; Shi, Lan; Liu, Changxiang; Zhang, Cunlin

    2018-01-01

    Artificial metamaterials with appropriate design can exhibit unique electromagnetic phenomena which do not exist in natural materials. Some studies have shown that the method of breaking the geometric symmetry is capable to modify the electromagnetic response, such as the metamaterial induced transparency in the Fano resonators. In this work, by using the finite-difference time-domain method, we firstly simulate the process that terahertz wave interacts with double-bar structures, in which one bar length is fixed at 36 μm and the other bar length is set to be 12, 24, 36, 48, and 56 μm, respectively. The incident terahertz polarization is along the bar direction. Simulated results show when the variable bar length is less than 36 μm, there is only one obvious resonant dip in transmission spectrum. Meanwhile, with the decreased bar length, this dip frequency presents a slight blueshift. Additionally, by tuning the spacing vertical to bar direction between these two bars, it still exhibits one dip. This result indicates the short bar less than 36 μm does not play important role and the coupling between vertical bars is weak. However, when the variable bar length is larger than 36 μm there are two obvious Fano-shaped resonant dips. With the increased bar length, the low-frequency dip shows a remarkable redshift, while the high-frequency one is almost unchanged. By further tuning the bar spacing vertical to the bar direction, two dips always exist. This phenomenon implies that the coupling between horizontal bars is dominated in this process. Moreover, the metamaterial induced transparency window is found between two resonant dips. The appearance of the resonances is attributed to the excitation of trapped mode. Our obtained results indicate that such metamaterials with very simple configuration could also provide the potential application in the field of terahertz slow-light devices, amplitude and phase modulators.

  18. Tunable Multilayer Graphene Metamaterials for Terahertz/Infrared Waveguide Modulators

    DEFF Research Database (Denmark)

    Khromova, Irina; Andryieuski, Andrei; Lavrinenko, Andrei

    of radiation. Various approaches have been proposed for THz/IR amplitude, phase, spatial and temporal profile modulation, including the employment of metamaterials [1] and, recently, one-atom-thick graphene [2]. Most of the proposed modulators, including graphene-based ones, are developed for free...... regimes of multilayer graphene-dielectric artificial metamaterials. The interplay between interband and intraband transitions in graphene allows converting the structure into a transparent and/or electromagnetically dense artificial medium. The gate voltage can be used to electrically control...... the concentration of carriers in the graphene sheets and, thus, efficiently change the dispersion of the whole structure. Placed inside a hollow waveguide, a multilayer graphene/dielectric metamaterial provides high-speed modulation and tunable bandpass filtering. The absence of scattered radiation enables dense...

  19. Enhancing Microbolometer Performance at Terahertz Frequencies with Metamaterial Absorbers

    Science.gov (United States)

    2013-09-01

    57  Figure 33.  Wheatstone bridge configuration for THz metamaterial microbolometer characterization. The thermally shorted...efficiently, but will have essentially the same thermal properties as the sensitive pixel. Several Wheatstone bridges are fabricated together, their...resistance in a microbolometer pixel, a Wheatstone bridge is employed in readout systems [10] as illustrated in Figure 33. To ensure the load

  20. Graphene metamaterial for multiband and broadband terahertz absorber

    Science.gov (United States)

    Gao, Runmei; Xu, Zongcheng; Ding, Chunfeng; Wu, Liang; Yao, Jianquan

    2015-12-01

    In this paper, we present the efficient design of functional graphene thin film metamaterial on a metal-plane separated by a thick dielectric layer. Perfect absorption is characterized by the complete suppression of incident and reflected light and complete dissipation of incident energy. We investigate the properties of graphene metamaterials and demonstrate multiband absorbers that have five absorption bands, using silicon interlayers, in the 0-2.2 THz range. The absorption rate reached up to 99.9% at a frequency of 1.08 THz, and the quality factor was 6.98 for a 0.14 THz bandwidth. We present a novel theoretical interpretation based on standing wave field theory, which shows that coherent superposition of the incident and reflection rays produce stationary waves, and the field energy localized inside the thick spacers and dissipated through the metal-planes. Thus, light was effectively trapped in the metamaterial absorbers with negligible near-field interactions, causing high absorption. The theory developed here explains all features observed in multiband metamaterial absorbers and therefore provides a profound understanding of the underlying physical mechanisms.

  1. Ultrafast refractive index control of a terahertz graphene metamaterial.

    Science.gov (United States)

    Lee, Seung Hoon; Choi, Jeongmook; Kim, Hyeon-Don; Choi, Hyunyong; Min, Bumki

    2013-01-01

    Modulation of the refractive index of materials is elementary, yet it is crucial for the manipulation of electromagnetic waves. Relying on the inherent properties of natural materials, it has been a long-standing challenge in device engineering to increase the index-modulation contrast. Here, we demonstrate a significant amount of ultrafast index modulation by optically exciting non-equilibrium Dirac fermions in the graphene layer integrated onto a high-index metamaterial. Furthermore, an extremely-large electrical modulation of refractive index up to Δn ~ -3.4 (at 0.69 THz) is achieved by electrical tuning of the density of the equilibrium Dirac fermion in the graphene metamaterial. This manifestation, otherwise remaining elusive in conventional semiconductor devices, fully exploits the characteristic ultrafast charge relaxation in graphene as well as the strong capacitive response of the metamaterial, both of which enable us to drastically increase the light-matter interaction of graphene and the corresponding index contrast in the graphene metamaterials.

  2. Hybrid Lead Halide Perovskites for Ultrasensitive Photoactive Switching in Terahertz Metamaterial Devices.

    Science.gov (United States)

    Manjappa, Manukumara; Srivastava, Yogesh Kumar; Solanki, Ankur; Kumar, Abhishek; Sum, Tze Chien; Singh, Ranjan

    2017-08-01

    The recent meteoric rise in the field of photovoltaics with the discovery of highly efficient solar-cell devices is inspired by solution-processed organic-inorganic lead halide perovskites that exhibit unprecedented light-to-electricity conversion efficiencies. The stunning performance of perovskites is attributed to their strong photoresponsive properties that are thoroughly utilized in designing excellent perovskite solar cells, light-emitting diodes, infrared lasers, and ultrafast photodetectors. However, optoelectronic application of halide perovskites in realizing highly efficient subwavelength photonic devices has remained a challenge. Here, the remarkable photoconductivity of organic-inorganic lead halide perovskites is exploited to demonstrate a hybrid perovskite-metamaterial device that shows extremely low power photoswitching of the metamaterial resonances in the terahertz part of the electromagnetic spectrum. Furthermore, a signature of a coupled phonon-metamaterial resonance is observed at higher pump powers, where the Fano resonance amplitude is extremely weak. In addition, a low threshold, dynamic control of the highly confined electric field intensity is also observed in the system, which could tremendously benefit the new generation of subwavelength photonic devices as active sensors, low threshold optically controlled lasers, and active nonlinear devices with enhanced functionalities in the infrared, optical, and the terahertz parts of the electromagnetic spectrum. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Materials and Mechanics of Metamaterial Enhanced MEMS for Terahertz Technology

    Science.gov (United States)

    2013-12-23

    for electrical excitation in comparison to magnetic excitation in terms of hybridization arising from inductive and capacitive coupling...the capacitive and inductive coupling. However, for ABC-SRRs, in-plane shifting between the two resonators by more than 0.375 Lo (Lo=SRR sidelength...Field by Radar Cross Section Measurements," Presented at the International Workshop on Optical Terahertz Science and Technology, Santa Barbara, CA

  4. Ultrafast refractive index control of a terahertz graphene metamaterial

    OpenAIRE

    Seung Hoon Lee; Jeongmook Choi; Hyeon-Don Kim; Hyunyong Choi; Bumki Min

    2013-01-01

    Modulation of the refractive index of materials is elementary, yet it is crucial for the manipulation of electromagnetic waves. Relying on the inherent properties of natural materials, it has been a long-standing challenge in device engineering to increase the index-modulation contrast. Here, we demonstrate a significant amount of ultrafast index modulation by optically exciting non-equilibrium Dirac fermions in the graphene layer integrated onto a high-index metamaterial. Furthermore, an ext...

  5. A three-dimensional all-metal terahertz metamaterial perfect absorber

    Science.gov (United States)

    Wu, Meng; Zhao, Xiaoguang; Zhang, Jingdi; Schalch, Jacob; Duan, Guangwu; Cremin, Kevin; Averitt, Richard D.; Zhang, Xin

    2017-07-01

    We present a three-dimensional terahertz metamaterial perfect absorber (MPA) that exhibits a high quality factor and is polarization insensitive. The unit cell is composed of two orthogonally oriented copper stand-up split ring resonators deposited on a copper ground plane with capacitive gaps in free space away from the substrate. Near unity (99.6%) absorption at ˜1.65 THz is experimentally obtained in excellent agreement with simulation results. The quality factor is ˜37, which is quite large for a terahertz MPA because of reduced material losses in the all-metal structure. According to simulation results, the MPA is insensitive to the polarization of the incident wave, and more than 90% absorption can be achieved for angles of incidence up to 60° for both TE and TM polarized incident THz waves.

  6. Terahertz dual-band metamaterial absorber based on graphene/MgF(2) multilayer structures.

    Science.gov (United States)

    Su, Zhaoxian; Yin, Jianbo; Zhao, Xiaopeng

    2015-01-26

    We design an ultra-thin terahertz metamaterial absorber based on graphene/MgF(2) multilayer stacking unit cells arrayed on an Au film plane and theoretically demonstrate a dual-band total absorption effect. Due to strong anisotropic permittivity, the graphene/MgF(2) multilayer unit cells possess a hyperbolic dispersion. The strong electric and magnetic dipole resonances between unit cells make the impedance of the absorber match to that of the free space, which induces two total absorption peaks in terahertz range. These absorption peaks are insensitive to the polarization and nearly omnidirectional for the incident angle. But the absorption intensity and frequency depend on material and geometric parameters of the multilayer structure. The absorbed electromagnetic waves are finally converted into heat and, as a result, the absorber shows a good nanosecond photothermal effect.

  7. Analog of electromagnetically induced transparency at terahertz frequency based on a bilayer-double-H-metamaterial

    Science.gov (United States)

    Wang, Yue’e.; Li, Zhi; Hu, Fangrong

    2018-01-01

    We designed a bilayer-double-H-metamaterials (BDHM) composed of two layers of metal and two layers of dielectric to analog a spectral response of electromagnetically induced transparency (EIT) at terahertz frequency. By changing the incident angle, the BDHM exhibits an EIT-like spectral response. The tunable spectral performances and modulation mechanism of the transparent peak are theoretically investigated using full-wave electromagnetic simulation software. The physical mechanism of the EIT-like effect is based on the constructive and destructive interference between the induced electrical dipoles. Our work provides a new way to realize the EIT-like effect only by changing the incident angles of the metamaterials. The potential applications include tunable filters, sensors, attenuators, switches, and so on.

  8. Frequency-tunable terahertz absorber with wire-based metamaterial and graphene

    Science.gov (United States)

    Xiong, Han; Jiang, Yan-Nan; Yang, Cheng; Zeng, Xiao-Ping

    2018-01-01

    We present a dynamically tunable metamaterial graphene absorber (MGA) in the terahertz regime. The unit cell of the proposed MGA consists of metal wire and graphene sheet over the grounded dielectric absorber. The MGA achieves frequency tunable characteristics via changing the chemical potential. In order to understand the absorption mechanism of this absorber, a simple equivalent circuit method has been proposed. Because the coupling between wire-based metamaterial and graphene is complicated and cannot be neglected an equivalent surface impedance was introduced and extracted for simplification. In addition to the chemical potential of graphene, the constitutive parameters of metal wire are also discussed in detail to completely understand how these factors affect the absorption properties. It is believed that this study may be useful for providing valuable guidance in the development of more advanced MGAs.

  9. Low-index-metamaterial for gain enhancement of planar terahertz antenna

    Directory of Open Access Journals (Sweden)

    Qing-Le Zhang

    2014-03-01

    Full Text Available We theoretically present a high gain planar antenna at terahertz (THz frequencies by combing a conventional log-periodic antenna (LPA with a low-index-metamaterial (LIM, |n| < 1. The LIM is realized by properly designing a fishnet metamaterial using full-wave finite-element simulation. Owing to the impedance matching, the LIM can be placed seamlessly on the substrate of the LPA without noticeable reflection. The effectiveness of using LIM for antenna gain enhancement is confirmed by comparing the antenna performance with and without LIM, where significantly improved half-power beam-width (3-dB beam-width and more than 4 dB gain enhancement are seen within a certain frequency range. The presented LIM-enhanced planar THz antenna is compact, flat, low profile, and high gain, which has extensive applications in THz systems, including communications, radar, and spectroscopy.

  10. Sensing self-assembled alkanethiols by differential transmission interrogation with terahertz metamaterials.

    Science.gov (United States)

    Wu, Xiaojun; Quan, Baogang; Pan, Xuecong; Xu, Xinlong; Lu, Xinchao; Xia, Xiaoxiang; Li, Junjie; Gu, Changzhi; Wang, Li

    2013-07-10

    Surface-enhanced electromagnetic response in the resonant regions of split-ring resonators offers a sensitive way to probe the surface dipoles formed by alkanethiol molecules with a terahertz wave by a differential transmission (DT) interrogation method. The DT signal mainly comes from the interaction between alkanethiols and metamaterials by electron transfer and/or the variation of the dielectric constant. The Lorentz model is used to demonstrate the principle of DT interrogation theoretically, which suggests the variation of both frequency and damping of resonance can be captured cooperatively. This method has been employed to experimentally demonstrate the sensing feasibility for the chain length dependence of the alkanethiol molecules. Numerical simulations confirm that the enhancement is large at the gap and corner regions of this kind of metamaterials.

  11. Extremely Nonperturbative Nonlinearities in GaAs Driven by Atomically Strong Terahertz Fields in Gold Metamaterials

    CERN Document Server

    Lange, C; Hohenleutner, M; Baierl, S; Schubert, O; Edwards, E; Bougeard, D; Woltersdorf, G; Huber, R

    2016-01-01

    Terahertz near fields of gold metamaterials resonant at a frequency of $0.88\\,\\rm THz$ allow us to enter an extreme limit of non-perturbative ultrafast THz electronics: Fields reaching a ponderomotive energy in the keV range are exploited to drive nondestructive, quasi-static interband tunneling and impact ionization in undoped bulk GaAs, injecting electron-hole plasmas with densities in excess of $10^{19}\\,\\rm cm^{-3}$. This process causes bright luminescence at energies up to $0.5\\,\\rm eV$ above the band gap and induces a complete switch-off of the metamaterial resonance accompanied by self-amplitude modulation of transmitted few-cycle THz transients. Our results pave the way towards highly nonlinear THz optics and optoelectronic nanocircuitry with sub-picosecond switching times.

  12. Graphene based tunable metamaterial absorber and polarization modulation in terahertz frequency.

    Science.gov (United States)

    Zhang, Yin; Feng, Yijun; Zhu, Bo; Zhao, Junming; Jiang, Tian

    2014-09-22

    Graphene can be utilized in designing tunable terahertz devices due to its tunability of sheet conductivity. In this paper, we combine the metamaterial having unit cell of cross-shaped metallic resonator with the double layer graphene wires to realize polarization independent absorber with spectral tuning at terahertz frequency. The absorption performance with a peak frequency tuning range of 15% and almost perfect peak absorption has been demonstrated by controlling the Fermi energy of the graphene that can be conveniently achieved by adjusting the bias voltage on the graphene double layers. The mechanism of the proposed absorber has been explored by a transmission line model and the tuning is explained by the changing of the effective inductance of the graphene wires under gate voltage biasing. Further more, we also propose a polarization modulation scheme of terahertz wave by applying similar polarization dependent absorbers. Through the proposed polarization modulator, it is able to electrically control the reflected wave with a linear polarization of continuously tunable azimuth angle of the major axis from 0° to 90° at the working frequency. These design approaches enable us to electrically control the absorption spectrum and the polarization state of terahertz waves more flexibly.

  13. Investigating Dielectric and Metamaterial Effects in a Terahertz Traveling-Wave Tube Amplifier

    Science.gov (United States)

    Starinshak, David P.; Wilson, Jeffrey D.

    2008-01-01

    Adding material enhancements to a terahertz traveling-wave tube amplifier is investigated. Isotropic dielectrics, negative-index metamaterials, and anisotropic crystals are simulated, and plans to increase the efficiency of the device are discussed. Early results indicate that adding dielectric to the curved sections of the serpentine-shaped slow-wave circuit produce optimal changes in the cold-test characteristics of the device and a minimal drop in operating frequency. Additional results suggest that materials with simultaneously small relative permittivities and electrical conductivities are best suited for increasing the efficiency of the device. More research is required on the subject, and recommendations are given to determine the direction.

  14. Ultra-flexible multiband terahertz metamaterial absorber for conformal geometry applications.

    Science.gov (United States)

    Yahiaoui, Riad; Guillet, Jean Paul; de Miollis, Frédérick; Mounaix, Patrick

    2013-12-01

    Standard optical lithography relying on clean room and microelectronic facilities is used to fabricate a thin-flexible metamaterial absorber, designed to operate at submillimeter wavelengths over the 0.1-1 THz frequency band. Large terahertz absorption has been demonstrated numerically and through experimental measurements with a maximum level of about 80%. We put emphasis in this present work on the use of single-sized "meta-cells" to achieve multiple absorption peaks. Furthermore, the use of a thin-flexible dielectric spacer makes it promising for stealth technology applications in order to disguise objects and make them less visible to radar and other detection methods.

  15. Novel quad-band terahertz metamaterial absorber based on single pattern U-shaped resonator

    Science.gov (United States)

    Wang, Ben-Xin; Wang, Gui-Zhen

    2017-03-01

    A novel quad-band terahertz metamaterial absorber using four different modes of single pattern resonator is demonstrated. Four obvious frequencies with near-perfect absorption are realized. Near-field distributions of the four modes are provided to reveal the physical picture of the multiple-band absorption. Unlike most previous quad-band absorbers that typically require four or more patterns, the designed absorber has only one resonant structure, which is simpler than previous works. The presented quad-band absorber has potential applications in biological sensing, medical imaging, and material detection.

  16. Trapping waves with terahertz metamaterial absorber based on isotropic Mie resonators.

    Science.gov (United States)

    Yahiaoui, Riad; Hanai, Kenichiro; Takano, Keisuke; Nishida, Tsubasa; Miyamaru, Fumiaki; Nakajima, Makoto; Hangyo, Masanori

    2015-07-01

    Quasi-monodisperse dielectric particles organized in a periodic hexagonal network on an aluminum surface are exploited numerically and experimentally as a single-layered near-perfect absorber in the terahertz regime. Of particular interest are titanium dioxide (TiO(2)) microspheres because of their large dielectric permittivity and isotropic shape leading to Mie resonances with insensitive polarization. Absorption higher than 80% at normal incidence covering two distinct ranges of frequencies is demonstrated experimentally. Furthermore, the performance of the metamaterial absorber is kept over a wide range of incident angles.

  17. HfO 2 -based ferroelectric modulator of terahertz waves with graphene metamaterial

    Science.gov (United States)

    Jiang, Ran; Wu, Zheng-Ran; Han, Zu-Yin; Jung, Hyung-Suk

    2016-10-01

    Tunable modulations of terahertz waves in a graphene/ferroelectric-layer/silicon hybrid structure are demonstrated at low bias voltages. The modulation is due to the creation/elimination of an extra barrier in Si layer in response to the polarization in the ferroelectric Si:HfO2 layer. Considering the good compatibility of HfO2 with the Si-based semiconductor process, the highly tunable characteristics of the graphene metamaterial device under ferroelectric effect open up new avenues for graphene-based high performance integrated active photonic devices compatible with the silicon technology. Project supported by the National Natural Science Foundation of China (Grant No. 11374182).

  18. Tunable terahertz electromagnetically induced transparency based on a complementary graphene metamaterial

    Science.gov (United States)

    Zhang, Huiyun; Zhang, Xiaoqiuyan; Cao, Yanyan; Zeng, Beibei; Zhou, Mingdong; Zhang, Yuping

    2017-01-01

    We proposed a dynamically tunable electromagnetically induced transparency (EIT) in the terahertz region based on a complementary graphene metamaterials within two asymmetric slot structures. A transparency peak is enabled through the coupling between the asymmetric slot-structure elements when their symmetry is broken. The width of transparency window can be controlled by varying the asymmetry degree. Moreover, by varying the Fermi energy of graphene, the transmission peak can be dynamically tuned, realizing a blue-shift without re-optimizing or re-fabricating the nanostructure. Therefore, the work opens up opportunities for the development of tunable compact elements such as slow light devices, sensors and switches.

  19. Fabrication of terahertz metamaterials using electrohydrodynamic jet printing for sensitive detection of yeast

    Science.gov (United States)

    Pradhipta Tenggara, Ayodya; Park, S. J.; Teguh Yudistira, Hadi; Ahn, Y. H.; Byun, Doyoung

    2017-03-01

    We demonstrated the fabrication of terahertz metamaterial sensor for the accurate and on-site detection of yeast using electrohydrodynamic jet printing, which is inexpensive, simple, and environmentally friendly. The very small sized pattern up to 5 µm-width of electrical split ring resonator unit structures could be printed on a large area on both a rigid substrate and flexible substrate, i.e. silicon wafer and polyimide film using the drop on demand technique to eject liquid ink containing silver nanoparticles. Experimental characterization and simulation were performed to study their performances in detecting yeast of different weights. It was shown that the metamaterial sensor fabricated on a flexible polyimide film had higher sensitivity by more than six times than the metamaterial sensor fabricated on a silicon wafer, due to the low refractive index of the PI substrate and due to the extremely thin substrate thickness which lowers the effective index further. The resonance frequency shift saturated when the yeast weights were 145 µg and 215 µg for metamaterial structures with gap size 6.5 µm fabricated on the silicon substrate and on the polyimide substrate, respectively.

  20. Thermally and optically tunable sub-terahertz superconducting fishnet metamaterial

    Science.gov (United States)

    Sabah, Cumali; Mulla, Batuhan; Altan, Hakan; Ozyuzer, Lutfi

    2018-01-01

    In this paper, a novel fishnet metamaterial structure is designed and analyzed under different material combinations and under different active controlling techniques. The results indicate that, the proposed fishnet metamaterial has a single resonance with double negativity at 0.39 THz when quartz substrate and aluminum is utilized in the design. Moreover, when the metallic parts are replaced with YBCO, the proposed design also exhibits double negativity with a stronger resonance and can be used as a switch between the double negative and single negative modes if the temperature is altered. In addition to these, when substrate (quartz) is replaced with MgO, the resonance shifts from 0.39 THz to 0.26 THz and shows double negativity. Moreover, switching properties under illumination can also be obtained when the silicon is utilized in the design (MgO-YBCO combination). According to these results, it is found that, in the case that the conductivity of silicon exceeds a certain value, the character of the resonance changes from double negative to the single negative mode.

  1. Active manipulation of electromagnetically induced reflection in complementary terahertz graphene metamaterial

    Science.gov (United States)

    He, Xunjun; Yao, Yuan; Huang, Yiming; Zhang, Qinfei; Zhu, Lei; Wu, Fengmin; Ying, Guobing; Jiang, Jiuxing

    2018-01-01

    A graphene-based metamaterial,featuring a dynamically tunable terahertz electromagnetically induced reflection (EIR) window, is numerically investigated in this paper. The designed metamaterial consists of a graphene single layer perforated with wire-slot pair array and a split-ring resonator slot (SRR-slot) structures printed on a SiO2/Si substrate, where the wire-slot pair and SRR-slot structures can act as the superradiant and subradiant elements, respectively. The surface current distributions demonstrate that the destructive interference caused by strong near field coupling between two resonators can induce a sharp reflection peak. Through varying lateral displacement between two resonators within the unit cell, moreover, the reflection peak amplitude and the corresponding group delay can be actively controlled due to the electromagnetic energy transfer between two resonators. In addition, the reflection peak can also exhibit obvious blue-shift by changing Fermi energy of graphene. Therefore, the work opens up the possibility for the development of compact terahertz elements such as modulators, switches and slow light devices.

  2. A three-dimensional ultra-broadband metamaterial absorber in terahertz region

    Science.gov (United States)

    Ling, Xinyan; Xiao, Zhongyin; Zheng, Xiaoxia; Tang, Jingyao; Xu, Kaikai

    2016-11-01

    In this paper, we proposed a three-dimensional metamaterial absorber with ultra-broadband in terahertz region. Compared with other three-layer structures, our structure is only composed of graphite film and a metal plate. The simulated results show that the metamaterial absorber can achieve an ultra-broadband absorption more than 90 % from 3 to 9 THz for either transverse electric or magnetic polarization wave at normal incidence. In addition, the absorption properties based on the oblique incidence and different polarization angles are also observed. A good absorption bandwidth can be kept when the incidence angle is up to 60°. Moreover, the absorber is polarization-insensitive with the polarization angle increase. Finally, the power loss density and surface current distributions at distinct resonance point are analyzed, which can demonstrate that the graphite plays an important role for the absorption of electromagnetic waves. We believe that the design idea of the three-dimensional metamaterial absorber maybe can extend to microwave, infrared or optical region.

  3. Electrically tunable superconducting terahertz metamaterial with low insertion loss and high switchable ratios

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chun; Zhang, Caihong, E-mail: chzhang@nju.edu.cn; Hu, Guoliang; Zhou, Gaochao; Jiang, Shoulu; Jiang, Chengtao; Zhu, Guanghao; Jin, Biaobing, E-mail: bbjin@nju.edu.cn; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng [Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China)

    2016-07-11

    With the emergence and development of artificially structured electromagnetic materials, active terahertz (THz) metamaterial devices have attracted significant attention in recent years. Tunability of transmission is desirable for many applications. For example, short-range wireless THz communications and ultrafast THz interconnects require switches and modulators. However, the tunable range of transmission amplitude of existing THz metamaterial devices is not satisfactory. In this article, we experimentally demonstrate an electrically tunable superconducting niobium nitride metamaterial device and employ a hybrid coupling model to analyze its optical transmission characteristics. The maximum transmission coefficient at 0.507 THz is 0.98 and decreases to 0.19 when the applied voltage increases to 0.9 V. A relative transmittance change of 80.6% is observed, making this device an efficient narrowband THz switch. Additionally, the frequency of the peak is red shifted from 0.507 to 0.425 THz, which means that the device can be used to select the frequency. This study offers an alternative tuning method to existing optical, thermal, magnetic-field, and electric-field tuning, delivering a promising approach for designing active and miniaturized THz devices.

  4. Terahertz ultrathin film thickness sensor below λ/90 based on metamaterial.

    Science.gov (United States)

    Chen, Meng; Fan, Fei; Shen, Si; Wang, Xianghui; Chang, Shengjiang

    2016-08-10

    The film thickness sensing based on metamaterial is investigated in the terahertz (THz) region. We fabricated the metamaterial sensor, and demonstrated its resonance by using the THz time-domain spectroscopy system. The results show that the resonant dip redshifts as the film thickness increases, which achieves reliable film sensing in the THz band. Its sensitivity is larger than 9.4 GHz/μm with a film thinner than λ/90. Meanwhile, the sensing mechanism is revealed by the simulation of near-field resonance distribution, which shows that the resonant intensity is stronger when the field is closer to the interface between the metamaterial surface and polyvinyl alcohol film. Therefore, the nonlinear type of the sensing sensitivity in our experiment can be well explained, and a higher sensitive sensing can be obtained when the film thickness is smaller. This simple and flexible method can realize the ultrathin film sensing in the THz region, and has application potential in the real-time monitoring of sample quality.

  5. Strong interaction between graphene layer and Fano resonance in terahertz metamaterials

    Science.gov (United States)

    Xiao, Shuyuan; Wang, Tao; Jiang, Xiaoyun; Yan, Xicheng; Cheng, Le; Wang, Boyun; Xu, Chen

    2017-05-01

    Graphene has emerged as a promising building block in modern optics and optoelectronics due to its novel optical and electrical properties. In the mid-infrared and terahertz (THz) regime, graphene behaves like metals and supports surface plasmon resonances (SPRs). Moreover, the continuously tunable conductivity of graphene enables active SPRs and gives rise to a range of active applications. However, the interaction between graphene and metal-based resonant metamaterials has not been fully understood. In this work, a simulation investigation on the interaction between the graphene layer and THz resonances supported by the two-gap split ring metamaterials is systematically conducted. The simulation results show that the graphene layer can substantially reduce the Fano resonance and even switch it off, while leaving the dipole resonance nearly unaffected, which is well explained with the high conductivity of graphene. With the manipulation of graphene conductivity via altering its Fermi energy or layer number, the amplitude of the Fano resonance can be modulated. The tunable Fano resonance here together with the underlying physical mechanism can be strategically important in designing active metal-graphene hybrid metamaterials. In addition, the ‘sensitivity’ to the graphene layer of the Fano resonance is also highly appreciated in the field of ultrasensitive sensing, where the novel physical mechanism can be employed in sensing other graphene-like two-dimensional materials or biomolecules with the high conductivity.

  6. High-performance terahertz wave absorbers made of silicon-based metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Sheng; Zhu, Jianfei; Jiang, Wei; Yuan, Jun; Yin, Ge; Ma, Yungui, E-mail: yungui@zju.edu.cn [State Key Lab of Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310058 (China); Xu, Wendao; Xie, Lijuan; Ying, Yibin [College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058 (China)

    2015-08-17

    Electromagnetic (EM) wave absorbers with high efficiency in different frequency bands have been extensively investigated for various applications. In this paper, we propose an ultra-broadband and polarization-insensitive terahertz metamaterial absorber based on a patterned lossy silicon substrate. Experimentally, a large absorption efficiency more than 95% in a frequency range of 0.9–2.5 THz was obtained up to a wave incident angle as large as 70°. Much broader absorption bandwidth and excellent oblique incidence absorption performance are numerically demonstrated. The underlying mechanisms due to the combination of a waveguide cavity mode and impedance-matched diffraction are analyzed in terms of the field patterns and the scattering features. The monolithic THz absorber proposed here may find important applications in EM energy harvesting systems such as THz barometer or biosensor.

  7. Photo-generated metamaterials induce modulation of CW terahertz quantum cascade lasers

    Science.gov (United States)

    Mezzapesa, Francesco P.; Columbo, Lorenzo L.; Rizza, Carlo; Brambilla, Massimo; Ciattoni, Alessardro; Dabbicco, Maurizio; Vitiello, Miriam S.; Scamarcio, Gaetano

    2015-11-01

    Periodic patterns of photo-excited carriers on a semiconductor surface profoundly modifies its effective permittivity, creating a stationary all-optical quasi-metallic metamaterial. Intriguingly, one can tailor its artificial birefringence to modulate with unprecedented degrees of freedom both the amplitude and phase of a quantum cascade laser (QCL) subject to optical feedback from such an anisotropic reflector. Here, we conceive and devise a reconfigurable photo-designed Terahertz (THz) modulator and exploit it in a proof-of-concept experiment to control the emission properties of THz QCLs. Photo-exciting sub-wavelength metastructures on silicon, we induce polarization-dependent changes in the intra-cavity THz field, that can be probed by monitoring the voltage across the QCL terminals. This inherently flexible approach promises groundbreaking impact on THz photonics applications, including THz phase modulators, fast switches, and active hyperbolic media.

  8. Broadband, polarization-insensitive and wide-angle terahertz metamaterial absorber

    Science.gov (United States)

    Wang, Ben-Xin; Wang, Ling-Ling; Wang, Gui-Zhen; Huang, Wei-Qing; Zhai, Xiang

    2014-11-01

    We present a broadband and polarization-insensitive terahertz metamaterial absorber formed from double-layered same-sized patterned square patches on top of a metallic ground plane. The combination of the two same-sized metallic patches gives rise to an absorption bandwidth of 380 GHz with absorption over 90%. The full width at half maximum of this device with respect to the central resonance frequency can be up to 33%, which is double that of a single-layered structure. The mechanism of the broadband absorber is attributed to longitudinal coupling between layers, and a hybridized charge distribution model is proposed for analyzing the origin of the resonance bandwidth. The proposed absorber has potential applications in detection, imaging and stealth technology.

  9. Structural imaging of nanoscale phonon transport in ferroelectrics excited by metamaterial-enhanced terahertz fields

    Science.gov (United States)

    Zhu, Yi; Chen, Frank; Park, Joonkyu; Sasikumar, Kiran; Hu, Bin; Damodaran, Anoop R.; Jung, Il Woong; Highland, Matthew J.; Cai, Zhonghou; Tung, I.-Cheng; Walko, Donald A.; Freeland, John W.; Martin, Lane W.; Sankaranarayanan, Subramanian K. R. S.; Evans, Paul G.; Lindenberg, Aaron M.; Wen, Haidan

    2017-11-01

    Nanoscale phonon transport is a key process that governs thermal conduction in a wide range of materials and devices. Creating controlled phonon populations by resonant excitation at terahertz (THz) frequencies can drastically change the characteristics of nanoscale thermal transport and allow a direct real-space characterization of phonon mean-free paths. Using metamaterial-enhanced terahertz excitation, we tailored a phononic excitation by selectively populating low-frequency phonons within a nanoscale volume in a ferroelectric BaTi O3 thin film. Real-space time-resolved x-ray diffraction microscopy following THz excitation reveals ballistic phonon transport over a distance of hundreds of nm, two orders of magnitude longer than the averaged phonon mean-free path in BaTi O3 . On longer length scales, diffusive phonon transport dominates the recovery of the transient strain response, largely due to heat conduction into the substrate. The measured real-space phonon transport can be directly compared with the phonon mean-free path as predicted by molecular dynamics modeling. This time-resolved real-space visualization of THz-matter interactions opens up opportunities to engineer and image nanoscale transient structural states with new functionalities.

  10. Gbps terahertz external modulator based on a composite metamaterial with a double-channel heterostructure.

    Science.gov (United States)

    Zhang, Yaxin; Qiao, Shen; Liang, Shixiong; Wu, Zhenhua; Yang, Ziqiang; Feng, Zhihong; Sun, Han; Zhou, Yucong; Sun, Linlin; Chen, Zhi; Zou, Xianbing; Zhang, Bo; Hu, Jianhao; Li, Shaoqian; Chen, Qin; Li, Ling; Xu, Gaiqi; Zhao, Yuncheng; Liu, Shenggang

    2015-05-13

    The past few decades have witnessed a substantial increase in terahertz (THz) research. Utilizing THz waves to transmit communication and imaging data has created a high demand for phase and amplitude modulation. However, current active THz devices, including modulators and switches, still cannot meet THz system demands. Double-channel heterostructures, an alternative semiconductor system, can support nanoscale two-dimensional electron gases (2DEGs) with high carrier concentration and mobility and provide a new way to develop active THz devices. In this Letter, we present a composite metamaterial structure that combines an equivalent collective dipolar array with a double-channel heterostructure to obtain an effective, ultrafast, and all-electronic grid-controlled THz modulator. Electrical control allows for resonant mode conversion between two different dipolar resonances in the active device, which significantly improves the modulation speed and depth. This THz modulator is the first to achieve a 1 GHz modulation speed and 85% modulation depth during real-time dynamic tests. Moreover, a 1.19 rad phase shift was realized. A wireless free-space-modulation THz communication system based on this external THz modulator was tested using 0.2 Gbps eye patterns. Therefore, this active composite metamaterial modulator provides a basis for the development of effective and ultrafast dynamic devices for THz wireless communication and imaging systems.

  11. Tunable electromagnetically induced transparency at terahertz frequencies in coupled graphene metamaterial

    Science.gov (United States)

    Ding, Guo-Wen; Liu, Shao-Bin; Zhang, Hai-Feng; Kong, Xiang-Kun; Li, Hai-Ming; Li, Bing-Xiang; Liu, Si-Yuan; Li, Hai

    2015-11-01

    A graphene-based metamaterial with tunable electromagnetically induced transparency (EIT)-like transmission is numerically studied in this paper. The proposed structure consists of a graphene layer composed of coupled cut-wire pairs printed on a substrate. The simulation confirms that an EIT-like transparency window can be observed due to indirect coupling in a terahertz frequency range. More importantly, the peak frequency of the transmission window can be dynamically controlled over a broad frequency range by varying the Fermi energy levels of the graphene layer through controlling the electrostatic gating. The proposed metamaterial structure offers an additional opportunity to design novel applications such as switches or modulators. Project supported by the National Natural Science Foundation of China (Grant No. 61307052), the Youth Funding for Science & Technology Innovation in Nanjing University of Aeronautics and Astronautics, China (Grant No. NS2014039), the Chinese Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20123218110017), the Innovation Program for Graduate Education of Jiangsu Province, China (Grant Nos. KYLX_0272, CXZZ13_0166, and CXLX13_155), the Open Research Program in National State Key Laboratory of Millimeter Waves of China (Grant No. K201609), and the Fundamental Research Funds for the Central Universities of China (Grant No. kfjj20150407).

  12. Electric-field tuning of a planar terahertz metamaterial based on strained SrTiO3 layers

    Science.gov (United States)

    Kadlec, Christelle; Skoromets, Volodymyr; Kadlec, Filip; Němec, Hynek; Chen, Hou-Tong; Jurka, Vlastimil; Hruška, Karel; Kužel, Petr

    2018-02-01

    We demonstrate a metamaterial exhibiting a frequency-tunable response in the terahertz domain, controlled by a bias electric field. The active part of the metamaterial consists of a periodic metallic pattern deposited on a thin epitaxially strained strontium titanate film. The role of the metallic structure is two-fold: it gives rise to the metamaterial resonance and it enables applying an electric bias to the strontium titanate layer. The strained film exhibits a pronounced dependence of its permittivity on the bias, which exerts a strong influence on the resonance. Specifically, the resonance of our structure occurs near 0.5 THz and, upon applying a bias voltage of 55 V, a relative tunability of the resonance frequency of 19% was achieved at room temperature.

  13. Comparison of gold- and graphene-based resonant nanostructures for terahertz metamaterials and an ultrathin graphene-based modulator

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Nian-Hai [Ames Laboratory; Tassin, Philippe [Ames Laboratory; Koschny, Thomas [Ames Laboratory; Soukoulis, Costas M [Ames Laboratory

    2014-09-01

    Graphene exhibits unique material properties, and in electromagnetic wave technology it raises the prospect of devices miniaturized down to the atomic length scale. Here we study split-ring resonator metamaterials made from graphene and we compare them to gold-based metamaterials. We find that graphene's huge reactive response derived from its large kinetic inductance allows for deeply subwavelength resonances, although its resonance strength is reduced due to higher dissipative loss damping and smaller dipole coupling. Nevertheless, tightly stacked graphene rings may provide for negative permeability and the electric dipole resonance of graphene meta-atoms turns out to be surprisingly strong. Based on these findings, we present a terahertz modulator based on a metamaterial with a multilayer stack of alternating patterned graphene sheets separated by dielectric spacers. Neighboring graphene flakes are biased against each other, resulting in modulation depths of over 75% at a transmission level of around 90%.

  14. A Route to Terahertz Metamaterial Biosensor Integrated with Microfluidics for Liver Cancer Biomarker Testing in Early Stage.

    Science.gov (United States)

    Geng, Zhaoxin; Zhang, Xiong; Fan, Zhiyuan; Lv, Xiaoqing; Chen, Hongda

    2017-11-27

    Engineered Terahertz (THz) metamaterials presented an unique characteristics for biosensing application due to their accurately tunable resonance frequency, which is in accord with vibrational frequency of some important biomolecules such as cancer biomarker. However, water absorption in THz regime is an obstacle to extend application in trace biomolecules of cancer antibody or antigen. Here, to overcome water absorption and enhance the THz biosensing sensitivity, two kinds of THz metamaterials biosensor integrated with microfluidics were fabricated and used to detect the Alpha fetoprotein (AFP) and Glutamine transferase isozymes II (GGT-II) of liver cancer biomarker in early stage. There were about 19 GHz resonance shift (5 mu/ml) and 14.2 GHz resonance shift (0.02524 μg/ml) for GGT-II and AFP with a two-gap-metamaterial, respectively, which agreed with simulation results. Those results demonstrated the power and usefulness of metamaterial-assisted THz spectroscopy in trace cancer biomarker molecular detection for biological and chemical sensing. Moreover, for a particular cancer biomarker, the sensitivity could be further improved by optimizing the metamaterial structure and decreasing the permittivity of the substrate. This method might be powerful and potential for special recognition of cancer molecules in the early stage.

  15. Fourcross shaped metamaterial filters fabricated from high temperature superconducting YBCO and Au thin films for terahertz waves

    Science.gov (United States)

    Demirhan, Y.; Alaboz, H.; Nebioğlu, M. A.; Mulla, B.; Akkaya, M.; Altan, H.; Sabah, C.; Ozyuzer, L.

    2017-07-01

    In this study, we present a new, unique fourcross shaped metamaterial terahertz (THz) filter fabricated from both gold thin films and YBa2Cu3O7-d high T c superconducting thin films. A commercial electromagnetic simulation software, CST Microwave Studio, is used to design and optimize the metamaterial filter structures. The proposed fourcross shaped rectangular filter structure consists of periodic metallic rings where strip lines are located at the sides of the ring. Fourcross metamaterial filters are fabricated by using e-beam lithography and ion beam etching techniques. Terahertz time-domain spectroscopy measurements validated the design predictions for both the center frequencies and bandwidths of the resonances due to the fourcross structures. The resonance switching of the transmission spectra was investigated by lowering the temperature below the critical transition temperature. This resonance switching effect is not observed in filters made up of metals. This novel fourcross rectangular resonator with a temperature-dependent resonance behavior holds great potential for active, tunable and low loss THz devices for imaging, sensing, and detection applications.

  16. Bulk magnetic terahertz metamaterial based on TiO2 microresonators(Conference Presentation)

    Science.gov (United States)

    Kadlec, Christelle; Sindler, Michal; Dominec, Filip; Němec, Hynek; Elissalde, Catherine; Mounaix, Patrick; Kuzel, Petr

    2017-05-01

    Dielectric spheres with high permittivity represent a Mie resonance-based metamaterial. Owing to its high far-infrared permittivity and low dielectric losses, TiO2 is a suitable material for the realization of magnetic metamaterials based on micro-resonators for the terahertz (THz) range. In a previous work, we experimentally demonstrated the magnetic effective response of TiO 2 microspheres dispersed in air, forming nearly a single-layer sample enclosed between two sapphire wafers [1]. Here we embedded the polycrystalline TiO2 microparticles into a polyethylene matrix, which enabled us to prepare a rigid bulk metamaterial with a controllable concentration of micro- resonators. TiO2 microspheres with a diameter of a few tens of micrometers were prepared by a bottom up approach. A liquid suspension of TiO2 nanoparticles was first spray-dried producing fragile TiO2 microspheres. These were subsequently sintered in a furnace at 1200° C for two hours, in order to consolidate individually each sphere. The particles show polycrystalline rutile structure with a porosity of 15%. The microspheres were finally sieved and sorted along their diameters in order to obtain a narrow size distribution. They were mixed with polyethylene powder and a pressure of 14 MPa was used to prepare rigid pellets with random spatial distribution of the TiO2 microspheres. Using finite-difference time-domain simulations, we investigated how the filling fraction and the ratio between the permittivities of the microspheres and the host matrix affect the position and the strength of the magnetic response associated with the lowest Mie mode. We found that a range of negative effective magnetic permeability can be achieved for sufficiently high filling factors and contrasts between the permittivities of the resonators and the embedding medium. Using time-domain THz spectroscopy we experimentally characterized the response of the realized structures and confirmed the magnetic character of their

  17. Double-stacked hyperbolic metamaterial waveguide arrays for efficient and broadband terahertz quarter-wave plates.

    Science.gov (United States)

    Ke, Xianmin; Zhu, Hua; Li, Junhao; Chen, Lin; Li, Xun

    2017-04-03

    We demonstrate how it is possible to achieve weak dispersion in the phase delay between two orthogonal polarization states by using double-stacked hyperbolic metamaterial (HMM) waveguide arrays. The weak dispersion in the phase delay originates from the different signs of phase delay from the two different HMM waveguide arrays. The condition of dispersion-free phase delay for the transmitted waves has been theoretically derived from the transmission matrix as the propagation characteristic of the HMM waveguide is involved. We further reveal that the designed double-stacked HMM waveguide array can function as an efficient quarter-wave plate that enables the conversion of linearly polarized light to circularly polarized light within a broad frequency band. In addition, the bandwidth over which the degree of linear polarization is nearly unity and over which the angle of linear polarization is kept at approximately 45° is basically consistent with the phase bandwidth. This offers a promising approach for developing a practical polarization converter in the terahertz domain.

  18. Investigation of a broadband refractory metal metamaterial absorber at terahertz frequencies.

    Science.gov (United States)

    Hu, Dan; Wang, Hongyan; Tang, Zhenjie; Zhang, Xiwei

    2016-07-01

    A broadband, polarization-independent, and wide-angle refractory metal metamaterial absorber is numerically investigated at terahertz frequencies, which consists of a periodic array of a chromium metallic loop and a chromium metallic film separated by a polyimide layer. Results show that a higher than 90% broadband absorption can be achieved for the range of frequencies from 1.00 through 2.43 THz, and the full absorption width at half-maximum can attain 110.80%, which is considerably larger than in previously reported results. Moreover, the greater than 90% broadband absorption response can still be maintained when the incidence angle increases to 45°. The physical origin of the proposed broadband absorber originates from localized surface plasmon resonances of the single metallic loop resonator. Furthermore, the designed concept also can be achieved in the visible and near-infrared region by rationally designing the dimensions of the absorber. This compact design has potential applications in stealth technology, energy harvesting, and thermal imaging.

  19. Solid analyte and aqueous solutions sensing based on a flexible terahertz dual-band metamaterial absorber

    Science.gov (United States)

    Yan, Xin; Liang, Lan-Ju; Ding, Xin; Yao, Jian-Quan

    2017-02-01

    A high-sensitivity sensing technique was demonstrated based on a flexible terahertz dual-band metamaterial absorber. The absorber has two perfect absorption peaks, one with a fundamental resonance (f1) of the structure and another with a high-order resonance (f2) originating from the interactions of adjacent unit cells. The quality factor (Q) and figure of merit of f2 are 6 and 14 times larger than that of f1, respectively. For the solid analyte, the changes in resonance frequency are monitored upon variation of analyte thickness and index; a linear relation between the amplitude absorption with the analyte thickness is achieved for f2. The sensitivity (S) is 31.2% refractive index units (RIU-1) for f2 and 13.7% RIU-1 for f1. For the aqueous solutions, the amplitude of absorption decreases linearly with increasing the dielectric constant for the ethanol-water mixture of f1. These results show that the designed absorber cannot only identify a solid analyte but also characterize aqueous solutions through the frequency shift and amplitude absorption. Therefore, the proposed absorber is promising for future applications in high-sensitivity monitoring biomolecular, chemical, ecological water systems, and aqueous biosystems.

  20. Investigation of tunable terahertz metamaterial perfect absorber with anisotropic dielectric liquid crystal

    Directory of Open Access Journals (Sweden)

    Mohammad P. Hokmabadi

    2017-01-01

    Full Text Available In this letter, we report the unique design, simulation and experimental verification of an electrically tunable THz metamaterial perfect absorber consisting of complementary split ring resonator (CSRR arrays integrated with liquid crystal as the subwavelength spacer in between. We observe a shift in resonance frequency of about 5.0 GHz at 0.567 THz with a 5 V bias voltage at 1KHz between the CSRR and the metal backplane, while the absorbance and full width at half maximum bandwidth are maintained at 90% and 0.025 THz, respectively. Simulated absorption spectrum by using a uniaxial model of LC matches perfectly the experiment data and demonstrates that the effective refractive index of LC changes between 1.5 and 1.7 by sweeping a 1 kHz bias voltage from 0 V to 5 V. By matching simulation and experiment for different bias voltages, we also estimate the angle of LC molecules versus the bias voltage. Additionally, we study the created THz fields inside the spacer to gain a better insight of the characteristics of tunable response of this device. This structure and associated study can support the design of liquid crystal based tunable terahertz detectors and sensors for various applications.

  1. Transmission line model and fields analysis of metamaterial absorber in the terahertz band.

    Science.gov (United States)

    Wen, Qi-Ye; Xie, Yun-Song; Zhang, Huai-Wu; Yang, Qing-Hui; Li, Yuan-Xun; Liu, Ying-Li

    2009-10-26

    Metamaterial (MM) absorber is a novel device to provide near-unity absorption to electromagnetic wave, which is especially important in the terahertz (THz) band. However, the principal physics of MM absorber is still far from being understood. In this work, a transmission line (TL) model for MM absorber was proposed, and with this model the S-parameters, energy consumption, and the power loss density of the absorber were calculated. By this TL model, the asymmetric phenomenon of THz absorption in MM absorber is unambiguously demonstrated, and it clarifies that strong absorption of this absorber under studied is mainly related to the LC resonance of the split-ring-resonator structure. The distribution of power loss density in the absorber indicates that the electromagnetic wave is firstly concentrated into some specific locations of the absorber and then be strongly consumed. This feature as electromagnetic wave trapper renders MM absorber a potential energy converter. Based on TL model, some design strategies to widen the absorption band were also proposed for the purposes to extend its application areas.

  2. Single- and double-sided sensor applications of metamaterials based on square-ring and diamond resonators for terahertz region

    Science.gov (United States)

    Shawky, Najlaa; Adnan Taha, Salah Al-Deen; Altan, Hakan; Sabah, Cumali

    2017-03-01

    This study investigates the sensing applications of metamaterial (MTM) structures in the terahertz (THz) region and is based on a broadside-coupled diamond and square-ring resonator (DSRR) structures. The resonators are designed and simulated as sensors in detail. Compared with single-sided sensors, the sensing capability of double-sided sensors provide an enhancement with respect to the sensitivity. To analyze the structure as sensor, the changes in the transmission resonance are investigated as a function of the permittivity and thickness of overlayer for the single- and double-sided MTM. The results demonstrate that this design can provide good sensitivity when sensing the chemical or biological agents that are resonant in the terahertz region of the electromagnetic spectrum. These types of designs can be employed in the many sensing applications that are of interest in the THz region.

  3. Metamaterials

    Science.gov (United States)

    Smith, David R.; Schurig, David; Starr, Anthony F.; Mock, Jack J.

    2014-09-09

    One exemplary metamaterial is formed from a plurality of individual unit cells, at least a portion of which have a different permeability than others. The plurality of individual unit cells are arranged to provide a metamaterial having a gradient index along at least one axis. Such metamaterials can be used to form lenses, for example.

  4. Terahertz band-pass filters based on fishnet metamaterials fabricated on free-standing SiNx membrane

    Science.gov (United States)

    Ao, Tianhong; Xu, Xiangdong; Gu, Yu; Chen, Zhegeng; Jiang, Yadong; Li, Xinrong; Lian, Yuxiang; Wang, Fu; He, Qiong; Chen, Zexiang; Zhou, Jun

    2017-12-01

    Terahertz (THz) band-pass filters constructed by metal-SiNx-metal hollow fishnet metamaterials were designed and fabricated. Results reveal that the as-fabricated single-layer filter responds at 3.75 THz with a high transmission of 88.1% and broad full width at half maximum of 2.79 THz. For such filters, a free-standing SiNx membrane is utilized specially as both dielectric and supporting materials, by which the insertion loss widely existed in those filters fabricated on rigid substrates can be efficiently avoided. Moreover, the critical parameters for determining the responses of the filters were systematically investigated. In our approach, multi-layer filters can be easily fabricated just by stacking the metamaterials layer by layer, and thus the spectral transmission, bandwidth, and out-of-band rejection can be rationally adjusted. This work describes a promising approach to design and fabricate THz band-pass filters based on substrate-free fishnet metamaterials.

  5. Metamaterial Composite with an Ultra-Broadband Usable Range of over 25 Terahertz

    DEFF Research Database (Denmark)

    Strikwerda, Andrew; Zalkovskij, Maksim; Krabbe, Alexander

    2014-01-01

    Using a metamaterial composite , we demonstrate a band pass filter that has only a single transmission mode from 0 to >25 THz. This usable bandwidth match es , or e xceed s , that of current ly used THz sources and demonstrates a path towards broadband metamaterial design.......Using a metamaterial composite , we demonstrate a band pass filter that has only a single transmission mode from 0 to >25 THz. This usable bandwidth match es , or e xceed s , that of current ly used THz sources and demonstrates a path towards broadband metamaterial design....

  6. A simple design of ultra-broadband and polarization insensitive terahertz metamaterial absorber

    Science.gov (United States)

    Wang, Ben-Xin; Wang, Ling-Ling; Wang, Gui-Zhen; Huang, Wei-Qing; Li, Xiao-Fei; Zhai, Xiang

    2014-06-01

    Ultra-broadband metamaterial absorbers have attracted considerable attention due to their great prospect for practical applications. These absorbers are usually stacked by many (no. stealth technology.

  7. Metamaterials

    CERN Document Server

    Cui, Tie Jun

    2009-01-01

    Includes an introduction to optical transformation theory, revealing invisible cloaks, EM concentrators, beam splitters, and new-type antennas. This title offers a presentation of general theory on artificial metamaterials composed of periodic structures, and coverage of a rapid design method for inhomogeneous metamaterials.

  8. Experimental realization of ultrathin, double-sided metamaterial perfect absorber at terahertz gap through stochastic design process.

    Science.gov (United States)

    Huang, Tsung-Yu; Tseng, Ching-Wei; Yeh, Ting-Tso; Yeh, Tien-Tien; Luo, Chih-Wei; Akalin, Tahsin; Yen, Ta-Jen

    2015-12-22

    We design and demonstrate a flexible, ultrathin and double-sided metamaterial perfect absorber (MPA) at 2.39 terahertz (THz), which enables excellent light absorbance under incidences from two opposite sides. Herein, the MPA is fabricated on a λ0/10.1-thick flexible polyethylene terephthalate substrate of εr = 2.75 × (1 + 0.12i), sandwiched by two identical randomized metallic patterns by our stochastic design process. Such an MPA provides tailored permittivity and permeability to approach the impedance of free space for minimizing reflectance and a great imaginary part of the refractive index for reducing transmittance and finally results in high absorbance. Both experimental measurement and numerical simulation are in a good agreement. The flexible, ultrathin and double-sided MPA significantly differs from traditional quarter-wavelength absorbers and other single-sided perfect absorbers, paving a way toward practical THz applications in thermal emission, sensing and imaging, communications, stealth technique, and even energy harvesting.

  9. Plasmonic Dimer Metamaterials and Metasurfaces for Polarization Control of Terahertz and Optical Waves

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Zalkovskij, Maksim; Malureanu, Radu

    2013-01-01

    We explore the capabilities of planar metamaterials and metasurfaces to control and transform the polarization of electromagnetic radiation, and present a detailed covariant multipole theory of dimer-based metamaterials. We show that various optical properties, such as optical activity, elliptical...

  10. A ‘T’ shaped flexible multiband ultra-thin terahertz metamaterial with consistent curved transmission spectra

    Science.gov (United States)

    Chen, Hairun; Yang, Bin; Zhao, Xiaoqing; Gui, Yan; Liu, Jingquan; Chen, Xiang; Wang, Xiaolin; Yang, Chunsheng

    2017-06-01

    In this paper, we designed a flexible multiband ultra-thin terahertz metamaterial with four ‘T’ shaped beams deposited on parylene-C substrate to achieve sensing. The simulated and experimental investigations of transmission spectra showed two resonant peaks, respectively, which demonstrated a good numerical and experimental agreement. Due to this special ‘T’ shaped structure, the transmission spectra were nearly unchanged in the first resonant peak and slightly fluctuant in the second resonant peak after bending with a constant step, which successfully confirmed a pretty consistent curved transmission performance. A further study about the effect of polarization and incident angle direction of terahertz wave on transmission spectra indicated that the transmission of the sample did not vary with the change of polarization angles but would be influenced by incident angles. In order to explore the performance of the structure in terms of sensing phenomenon, a final contrast simulation on different surface analytes and without analyte was carried out, consequently suggesting a promising and remarkable function in sensing applications especially in detecting biomolecules.

  11. A single-patterned five-band terahertz metamaterial absorber based on multiple resonance mechanisms

    Science.gov (United States)

    Ju, Zong-De; Xu, Guo-Qing; Wei, Zhi-Hua; Li, Jing; Zhao, Qian; Huang, Jie

    2018-01-01

    A single-patterned five-band terahertz metamaterial absorber based on simple metal-dielectric-metal sandwich structure is investigated and demonstrated. The numerical simulations reveal the different dependence of the absorption ability on the incident polarization angle, dielectric layer, and structural dimensions of the single pattern. The extracted electric field distribution indicates that the five-band near-perfect absorption performance (average over 98%) mainly originates from the combination of LC, dipole, quadrupole, and high-order resonance. The researches on magnetic field and power loss density distributions further reveal the absorption mechanism. Moreover, additional resonance mode can be excited to form a six-band high-performance absorber only by adjusting some geometric dimensions of the single pattern with multiple resonance modes. The simple method provides us a very good idea to implement a super multi-band absorber. The proposed absorbers here can be applied in massive related fields, such as metamaterial sensors, thermal radiation, and imaging system.

  12. Anisotropy modeling of terahertz metamaterials: polarization dependent resonance manipulation by meta-atom cluster.

    Science.gov (United States)

    Jung, Hyunseung; In, Chihun; Choi, Hyunyong; Lee, Hojin

    2014-06-09

    Recently metamaterials have inspired worldwide researches due to their exotic properties in transmitting, reflecting, absorbing or refracting specific electromagnetic waves. Most metamaterials are known to have anisotropic properties, but existing anisotropy models are applicable only to a single meta-atom and its properties. Here we propose an anisotropy model for asymmetrical meta-atom clusters and their polarization dependency. The proposed anisotropic meta-atom clusters show a unique resonance property in which their frequencies can be altered for parallel polarization, but fixed to a single resonance frequency for perpendicular polarization. The proposed anisotropic metamaterials are expected to pave the way for novel optical systems.

  13. Structural control of metamaterial oscillator strength and electric field enhancement at terahertz frequencies

    DEFF Research Database (Denmark)

    Keiser, G. R.; Seren, H. R.; Strikwerda, Andrew C.

    2014-01-01

    The design of artificial nonlinear materials requires control over internal resonant charge densities and local electric field distributions. We present a MM design with a structurally controllable oscillator strength and local electric field enhancement at terahertz frequencies. The MM consists ...

  14. Comparison of gold- and graphene-based resonant nano-structures for terahertz metamaterials and an ultra-thin graphene-based modulator

    CERN Document Server

    Shen, Nian-Hai; Koschny, Thomas; Soukoulis, Costas M

    2014-01-01

    Graphene exhibits unique material properties and in electromagnetic wave technology, it raises the prospect of devices miniaturized down to the atomic length scale. Here we study split-ring resonator metamaterials made from graphene and we compare them to gold-based metamaterials. We find that graphene's huge reactive response derived from its large kinetic inductance allows for deeply subwavelength resonances, although its resonance strength is reduced due to higher dissipative loss damping and smaller dipole coupling. Nevertheless, tightly stacked graphene rings may provide for negative permeability and the electric dipole resonance of graphene meta-atoms turns out to be surprisingly strong. Based on these findings, we present a terahertz modulator based on a metamaterial with a multi-layer stack of alternating patterned graphene sheets separated by dielectric spacers. Neighbouring graphene flakes are biased against each other, resulting in modulation depths of over 75% at a transmission level of around 90%...

  15. Broadband terahertz wave deflection based on C-shape complex metamaterials with phase discontinuities

    KAUST Repository

    Zhang, Xueqian

    2013-06-21

    A broadband terahertz wave deflector based on metasurface induced phase discontinuities is reported. Various frequency components ranging from 0.43 to 1.0 THz with polarization orthogonal to the incidence are deflected into a broad range of angles from 25° to 84°. A Fresnel zone plate consequently developed from the beam deflector is capable of focusing a broadband terahertz radiation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Complementary graphene metamaterial with independently tunable dual absorption bands at terahertz frequency

    Science.gov (United States)

    Li, Lei; Cao, Maoyong; Li, Tongtong; Meng, Lihua; Zhang, Huiyun; Zhang, Yuping

    2017-10-01

    We design an independently tunable dual-band terahertz absorber consisting of graphene ribbons patterned with a combination of two complementary crosses of different sizes within a unit-cell. The Fermi energy of the interdigitated graphene ribbons can be tuned independently via applied gate voltages. Our simulations indicate that the absorption at two resonant bands can be ~75% under normal incidence. In addition, our design allows independent tuning of the resonant frequencies by changing the Fermi energy of graphene via controlling the applied bias voltages. Our results may find application in developing frequency tunable terahertz modulators, sensors, and detectors.

  17. Anisotropic anti-rod dimer metamaterial film for terahertz polarization manipulation

    DEFF Research Database (Denmark)

    Zalkovskij, Maksim; Malureanu, Radu; Novitsky, Andrey

    2012-01-01

    We demonstrate the concept of an anti-rod dimer planar metamaterial with strong birefringence and optical activity in the THz range. The retrieval of circular transmission components shows an asymmetric transmission effect for right-to-left and left-to-right polarization conversion....

  18. Permanently reconfigured metamaterials due to terahertz induced mass transfer of gold

    DEFF Research Database (Denmark)

    Strikwerda, Andrew; Zalkovskij, Maksim; Iwaszczuk, Krzysztof

    2015-01-01

    response is dictated by its geometry, this structural change massively alters the metamaterial's behavior. We show this by optically forming a conducting pathway between two closely spaced dipole antennas, thereby changing the resonance frequency by a factor of two. After discussing the physics...

  19. Subwavelength silicon through-hole arrays as an all-dielectric broadband terahertz gradient index metamaterial

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang-Gil; Jeong, Ki-Hun, E-mail: kjeong@kaist.ac.kr [Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); KAIST Institute for Optical Science and Technology, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Lee, Kanghee; Han, Daehoon; Ahn, Jaewook [KAIST Institute for Optical Science and Technology, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2014-09-01

    Structuring at subwavelength scales brings out artificial media with anomalous optical features called metamaterials. All-dielectric metamaterials have high potential for practical applications over the whole electromagnetic spectrum owing to low loss and optical isotropy. Here, we report subwavelength silicon through-hole arrays as an all-dielectric gradient index metamaterial with broadband THz operation. The unit cell consists of a single subwavelength through-hole on highly resistive monocrystalline silicon. Depending on the fill-factor and period, the effective index was linearly modulated at 0.3–1.6 THz. The experimental results also demonstrate silicon gradient refractive index (Si-GRIN) lenses with parabolic index profiles through the spatial modification of a single unit cell along the radial direction. Si-GRIN lenses either focus 0.4–1.6 THz beam to the diffraction-limit or serve as a flat and thin solid immersion lens on the backside of THz photoconductive antenna for highly efficient pulse extraction. This all-dielectric gradient index metamaterial opens up opportunities for integrated THz GRIN optics.

  20. Slot-dimer babinet metamaterials as polarization shapers for terahertz waves

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Chigrin, D. N.; Lavrinenko, Andrei

    2013-01-01

    We theoretically study optical properties of free-standing metallic membranes patterned with an array of two-slot elements (dimers) comprising two rectangular slots of different dimensions and orientation. It is shown that these structures feature extraordinary optical transmission with strong an...... and spectrally selective polarization conversion capabilities. The output polarization is highly dependent on the dimer geometry, which can be used in the design of compact polarization shapers for terahertz waves....

  1. Broadband terahertz generation from metamaterials and their hybrid quantum structures (Conference Presentation)

    Science.gov (United States)

    Wang, Jigang

    2017-02-01

    The terahertz spectral regime, ranging from about 0.1-15 THz, is one of the least explored yet most technologically transformative spectral regions. One current challenge is to develop efficient and compact terahertz emitters/detectors with a broadband and gapless spectrum that can be tailored for various pump photon energies. A particularly essential and topical question is how to create nonlinear broadband terahertz devices using deeply subwavelength nanoscale meta-atom resonators. Here we demonstrate efficient single-cycle broadband THz generation, ranging from about 0.1-4 THz, in two model hybrid quantum nanostructures: (1) a thin layer of split-ring resonators (SRRs) with few tens of nanometers thickness by pumping at the telecommunications wavelength of 200 THz; (2) SRRs coupled to intersubband transitions in quantum wells pumping at 30 THz. We also reveal a giant sheet nonlinear susceptibility that far exceeds thin films and bulk non-centrosymmetric materials. Finally, I will also discuss their significances for THz enabled nonlinear spectroscopy and quantum phase discovery applications.

  2. Active terahertz metamaterials based on the phase transition of VO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H., E-mail: heungsoo.kim@nrl.navy.mil [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States); Charipar, N. [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States); Breckenfeld, E. [National Research Council Fellow at the Naval Research Laboratory, Washington, DC 20375 (United States); Rosenberg, A. [NOVA Research, Inc., Alexandria, VA 22308 (United States); Piqué, A. [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2015-12-01

    Vanadium dioxide (VO{sub 2}) thin films were prepared on single crystal sapphire substrates by pulsed laser deposition. VO{sub 2} films exhibited a significant resistivity drop (> 10{sup 4} Ω-cm) and large optical transmittance change (> 60%) in the near-infrared region across their semiconductor-to-metal transition. Hybrid metamaterial devices designed for the THz frequency regime were fabricated by combining double split-ring resonators (SRRs) with phase changing VO{sub 2} films. By changing the conductivity of VO{sub 2} via temperature, the behavior of the SRR gap was adjusted from capacitive to resistive in order to modulate the THz beam transmission at their resonance frequencies. A modulation efficiency greater than 50% was achieved at the magnetic resonance frequencies (0.3 THz and 0.7 THz) in these hybrid SRR–VO{sub 2} metamaterial devices. - Highlights: • Pulsed laser deposition of phase changing VO{sub 2} thin films • Hybrid metamaterial devices composed of split-ring resonators and phase changing VO{sub 2} • Tunable THz transmission with a modulation efficiency over 50%.

  3. A polarization-independent terahertz plasmon-induced transparency metamaterial based on hybrid graphene-gold structure for bio-sensing

    Science.gov (United States)

    Zhao, Xiaolei; Yuan, Cai; Lv, Wenhua; Xu, Shilin; Yao, Jianquan

    2016-02-01

    A polarization-independent terahertz metamaterial based on hybrid graphene-gold structure with excellent refractive index sensing characteristics is proposed. The proposed structure exhibits a sharply narrow plasmon-induced transparency peak in the transmission spectrum at the terahertz regime. Obvious frequency shift in the transparency peak can be observed by varying the surrounding medium's refractive index or the Fermi level in graphene, which can be well applied in bio-sensing technology. Moreover, an electrical RLC circuit model is used to provide a reasonable explanation for the optical response process in the proposed structure. Our work can offer reference value for the application of graphene technology as well as new idea for designing novel biosensors.

  4. Broadband and polarization-insensitive helix metamaterial absorber using graphene for terahertz region

    Science.gov (United States)

    Agarwal, Sajal; Prajapati, Y. K.

    2016-06-01

    A polarization-independent broadband metamaterial absorber having graphene layer is proposed in this study. It is found that the absorption spectrum of the absorber becomes more promising after using graphene layers. Graphene layer increases the device robustness and stability of the device. The proposed absorber works for a wide operating region covering near ultraviolet to near infrared, i.e., 200-1792 nm. Absorption characteristics including the operating wavelength and the polarization nature of various existing absorbers is compared with the proposed absorber. It is noticed that the proposed absorber is physically realizable since it has a sufficiently large geometry and resistivity toward change in the number of graphene layers.

  5. Electrically tunable terahertz polarization converter based on overcoupled metal-isolator-metal metamaterials infiltrated with liquid crystals

    Science.gov (United States)

    Vasić, Borislav; Zografopoulos, Dimitrios C.; Isić, Goran; Beccherelli, Romeo; Gajić, Radoš

    2017-03-01

    Large birefringence and its electrical modulation by means of Fréedericksz transition makes nematic liquid crystals (LCs) a promising platform for tunable terahertz (THz) devices. The thickness of standard LC cells is in the order of the wavelength, requiring high driving voltages and allowing only a very slow modulation at THz frequencies. Here, we first present the concept of overcoupled metal-isolator-metal (MIM) cavities that allow for achieving simultaneously both very high phase difference between orthogonal electric field components and large reflectance. We then apply this concept to LC-infiltrated MIM-based metamaterials aiming at the design of electrically tunable THz polarization converters. The optimal operation in the overcoupled regime is provided by properly selecting the thickness of the LC cell. Instead of the LC natural birefringence, the polarization-dependent functionality stems from the optical anisotropy of ultrathin and deeply subwavelength MIM structures. The dynamic electro-optic control of the LC refractive index enables the spectral shift of the resonant mode and, consequently, the tuning of the phase difference between the two orthogonal field components. This tunability is further enhanced by the large confinement of the resonant electromagnetic fields within the MIM cavity. We show that for an appropriately chosen linearly polarized incident field, the polarization state of the reflected field at the target operation frequency can be continuously swept between the north and south pole of the Poincaré sphere. Using a rigorous Q-tensor model to simulate the LC electro-optic switching, we demonstrate that the enhanced light-matter interaction in the MIM resonant cavity allows the polarization converter to operate at driving voltages below 10 Volt and with millisecond switching times.

  6. Ultrasensitive terahertz/infrared waveguide modulators based on multilayer graphene metamaterials

    DEFF Research Database (Denmark)

    Khromova, Irina; Andryieuski, Andrei; Lavrinenko, Andrei

    2014-01-01

    This paper studies and classifies the electromagnetic regimes of multilayer graphene-dielectric artificial metamate- rials in the terahertz/infrared range. The employment of such composites for waveguide-integrated modulators is analysed and three examples of novel tunable devices are presented....... The first one is a modulator with excellent ON-state transmission and very high modulation depth: > 38 dB at 70 meV graphene’s electrochemical potential (Fermi energy) change. The second one is a modulator with extreme sensitivity towards graphene’s Fermi energy - a minute 1 meV variation of the latter...... leads to > 13 . 2 dB modulation depth. The third one is a tunable waveguide-based passband filter. The narrow-band cut-off con- ditions around the ON-state allow the latter to shift its central frequency by 1 . 25% per every meV graphene’s Fermi energy change...

  7. Terahertz Response of a Microfabricated Rod Split-Ring-Resonator Electromagnetic Metamaterial

    Science.gov (United States)

    Moser, H. O.; Casse, B. D.; Wilhelmi, O.; Saw, B. T.

    2005-02-01

    The first electromagnetic metamaterials (EM3) produced by microfabrication are reported. They are based on the rod split-ring-resonator design as proposed by Pendry et al. [IEEE Trans. Microwave Theory Tech. 47, 2075 (1999)IETMAB0018-948010.1109/22.798002] and experimentally confirmed by Smith et al. [Phys. Rev. Lett.PRLTAO0031-9007 84, 4184 (2000)10.1103/PhysRevLett.84.4184] in the GHz frequency range. Numerical simulation and experimental results from far infrared (FIR) transmission spectroscopy support the conclusion that the microfabricated composite material is EM3 in the range 1 2.7 THz. This extends the frequency range in which EM3 are available by about 3 orders of magnitude well into the FIR, thereby widely opening up opportunities to verify the unusual physical implications on electromagnetic theory as well as to build novel electromagnetic and optical devices.

  8. LiTaO3 based metamaterial perfect absorber for terahertz spectrum

    Science.gov (United States)

    Shankhwar, Nishant; Kalra, Yogita; Sinha, Ravindra Kumar

    2017-11-01

    In this article a new design of metamaterial perfect absorber (MPA) has been proposed which comprises a periodic array of LiTaO3 microcylinders grown over a silver substrate. The fundamental principle of the structure is the occurrence of Mie resonance in the cylinders due to high value of refractive index (∼10) of LiTaO3 in the wavelength range 65-100 μm. This remarkably high refractive index is a manifestation of polaritonic resonance of LiTaO3 in the considered wavelength range. The proposed structure shows high absorption coefficient in the said wavelength range with a maximum of 99.9% around 88 μm.

  9. Optically Modulated Multiband Terahertz Perfect Absorber

    DEFF Research Database (Denmark)

    Seren, Huseyin R.; Keiser, George R.; Cao, Lingyue

    2014-01-01

    response of resonant metamaterials continues to be a challengingendeavor. Resonant perfect absorbers have flourished as one of the mostpromising metamaterial devices with applications ranging from power har-vesting to terahertz imaging. Here, an optically modulated resonant perfectabsorber is presented...

  10. Fast terahertz optoelectronic amplitude modulator based on plasmonic metamaterial antenna arrays and graphene

    Science.gov (United States)

    Jessop, David S.; Sol, Christian W. O.; Xiao, Long; Kindness, Stephen J.; Braeuninger-Weimer, Philipp; Lin, Hungyen; Griffiths, Jonathan P.; Ren, Yuan; Kamboj, Varun S.; Hofmann, Stephan; Zeitler, J. Axel; Beere, Harvey E.; Ritchie, David A.; Degl'Innocenti, Riccardo

    2016-02-01

    The growing interest in terahertz (THz) technologies in recent years has seen a wide range of demonstrated applications, spanning from security screening, non-destructive testing, gas sensing, to biomedical imaging and communication. Communication with THz radiation offers the advantage of much higher bandwidths than currently available, in an unallocated spectrum. For this to be realized, optoelectronic components capable of manipulating THz radiation at high speeds and high signal-to-noise ratios must be developed. In this work we demonstrate a room temperature frequency dependent optoelectronic amplitude modulator working at around 2 THz, which incorporates graphene as the tuning medium. The architecture of the modulator is an array of plasmonic dipole antennas surrounded by graphene. By electrostatically doping the graphene via a back gate electrode, the reflection characteristics of the modulator are modified. The modulator is electrically characterized to determine the graphene conductivity and optically characterization, by THz time-domain spectroscopy and a single-mode 2 THz quantum cascade laser, to determine the optical modulation depth and cut-off frequency. A maximum optical modulation depth of ~ 30% is estimated and is found to be most (least) sensitive when the electrical modulation is centered at the point of maximum (minimum) differential resistivity of the graphene. A 3 dB cut-off frequency > 5 MHz, limited only by the area of graphene on the device, is reported. The results agree well with theoretical calculations and numerical simulations, and demonstrate the first steps towards ultra-fast, graphene based THz optoelectronic devices.

  11. Multispectral metamaterial absorber

    OpenAIRE

    Grant, James; McCrindle, I.J.H.; Li, C; D. R. S. Cumming

    2014-01-01

    We present the simulation, implementation, and measurement of a multispectral metamaterial absorber (MSMMA) and show that we can realize a simple absorber structure that operates in the mid-IR and terahertz (THz) bands. By embedding an IR metamaterial absorber layer into a standard THz metamaterial absorber stack, a narrowband resonance is induced at a wavelength of 4.3 μm. This resonance is in addition to the THz metamaterial absorption resonance at 109 μm (2.75 THz). We demonstrate the inhe...

  12. Ultrathin Six-Band Polarization-Insensitive Perfect Metamaterial Absorber Based on a Cross-Cave Patch Resonator for Terahertz Waves.

    Science.gov (United States)

    Cheng, Yong Zhi; Huang, Mu Lin; Chen, Hao Ran; Guo, Zhen Zhong; Mao, Xue Song; Gong, Rong Zhou

    2017-05-28

    A simple design of an ultrathin six-band polarization-insensitive terahertz perfect metamaterial absorber (PMMA), composed of a metal cross-cave patch resonator (CCPR) placed over a ground plane, was proposed and investigated numerically. The numerical simulation results demonstrate that the average absorption peaks are up to 95% at six resonance frequencies. Owing to the ultra-narrow band resonance absorption of the structure, the designed PMMA also exhibits a higher Q factor (>65). In addition, the absorption properties can be kept stable for both normal incident transverse magnetic (TM) and transverse electric (TE) waves. The physical mechanism behind the observed high-level absorption is illustrated by the electric and power loss density distributions. The perfect absorption originates mainly from the higher-order multipolar plasmon resonance of the structure, which differs sharply from most previous studies of PMMAs. Furthermore, the resonance absorption properties of the PMMA can be modified and adjusted easily by varying the geometric parameters of the unit cell.

  13. Ultrathin Six-Band Polarization-Insensitive Perfect Metamaterial Absorber Based on a Cross-Cave Patch Resonator for Terahertz Waves

    Directory of Open Access Journals (Sweden)

    Yong Zhi Cheng

    2017-05-01

    Full Text Available A simple design of an ultrathin six-band polarization-insensitive terahertz perfect metamaterial absorber (PMMA, composed of a metal cross-cave patch resonator (CCPR placed over a ground plane, was proposed and investigated numerically. The numerical simulation results demonstrate that the average absorption peaks are up to 95% at six resonance frequencies. Owing to the ultra-narrow band resonance absorption of the structure, the designed PMMA also exhibits a higher Q factor (>65. In addition, the absorption properties can be kept stable for both normal incident transverse magnetic (TM and transverse electric (TE waves. The physical mechanism behind the observed high-level absorption is illustrated by the electric and power loss density distributions. The perfect absorption originates mainly from the higher-order multipolar plasmon resonance of the structure, which differs sharply from most previous studies of PMMAs. Furthermore, the resonance absorption properties of the PMMA can be modified and adjusted easily by varying the geometric parameters of the unit cell.

  14. Six-band terahertz metamaterial absorber based on the combination of multiple-order responses of metallic patches in a dual-layer stacked resonance structure.

    Science.gov (United States)

    Wang, Ben-Xin; Wang, Gui-Zhen; Sang, Tian; Wang, Ling-Ling

    2017-01-25

    This paper reports on a numerical study of the six-band metamaterial absorber composed of two alternating stack of metallic-dielectric layers on top of a continuous metallic plane. Six obvious resonance peaks with high absorption performance (average larger than 99.37%) are realized. The first, third, fifth, and the second, fourth, sixth resonance absorption bands are attributed to the multiple-order responses (i.e., the 1-, 3- and 5-order responses) of the bottom- and top-layer of the structure, respectively, and thus the absorption mechanism of six-band absorber is due to the combination of two sets of the multiple-order resonances of these two layers. Besides, the size changes of the metallic layers have the ability to tune the frequencies of the six-band absorber. Employing the results, we also present a six-band polarization tunable absorber through varying the sizes of the structure in two orthogonal polarization directions. Moreover, nine-band terahertz absorber can be achieved by using a three-layer stacked structure. Simulation results indicate that the absorber possesses nine distinct resonance bands, and average absorptivities of them are larger than 94.03%. The six-band or nine-band absorbers obtained here have potential applications in many optoelectronic and engineering technology areas.

  15. Electrically switchable metamaterials and devices (Conference Presentation)

    Science.gov (United States)

    Chen, Hou-Tong

    2016-09-01

    The promise of metamaterials lies in the realization of desirable electromagnetic functionalities simply through tailoring the geometric structure and deliberate arrangement of metal/dielectric building blocks (meta-atoms) to yield envisaged material properties that may be difficult or impossible to accomplish using natural materials. Integration of functional materials into metamaterial structures further extends switchable and frequency tunable functionalities through applying an external stimulus such as temperature change, photoexcitation, and voltage bias. Among them electrically switchable metamaterials are of particular interest for a host of applications. In this work we present our recent progress in this direction. More specifically, hybrid terahertz metamaterials can be formed through integrating semiconducting Schottky junctions into the metallic resonators, enabling highly efficient, electrically switchable resonant response. Such hybrid terahertz metamaterials can be applied in creating terahertz spatial light modulators and active diffraction gratings. Furthermore, graphene can be used to extend the active metamaterials to the mid-infrared frequency range.

  16. EDITORIAL: Terahertz nanotechnology Terahertz nanotechnology

    Science.gov (United States)

    Demming, Anna; Tonouchi, Masayoshi; Reno, John L.

    2013-05-01

    within the THz spectral region providing an additional benefit. His review describes the principle, characteristics, and applications of terahertz molecular imaging, where the use of nanoparticle probes allows dramatically enhanced sensitivity. Jiaguang Han and Weili Zhang and colleagues in China, Saudi Arabia, Japan and the US report exciting developments for optoelectronics [11]. They describe work on plasmon-induced transparency (PIT), an analogue of electromagnetically induced transparency (EIT) where interference leads to a sharp transparency window that may be useful for nonlinear and slow-light devices, optical switching, pulse delay, and storage for optical information processing. While PIT has advantages over the cumbersome experimental systems required for EIT, it has so far been constrained to very narrow band operation. Now Zhang and colleagues present the simulation, implementation, and measurement of a broadband PIT metamaterial functioning across a frequency range greater than 0.40 THz in the terahertz regime. 'We can foresee a historic breakthrough for science and technology through terahertz research,' concluded Masayoshi Tonouchi in his review over five years ago as momentum in the field was mounting [12]. He added, 'It is also noteworthy that THz research is built on many areas of science and the coordination of a range of disciplines is giving birth to a new science.' With the inherently multidisciplinary nature of nanotechnology research it is not so strange to see the marriage of the two fields form such a fruitful partnership, as this special section highlights. References [1] Williams B S, Kumar S, Hu Q and Reno J L 2006 High-power terahertz quantum-cascade lasers Electron. Lett. 42 89-91 [2] Köhler R et al 2002 Terahertz semiconductor-heterostructure laser Nature 417 156-9 [3] Mittendorff M, Xu M, Dietz R J B, K¨unzel H, Sartorius B, Schneider H, Helm M and Winnerl S 2013 Large area photoconductive THz emitter for 1.55 μm excitation based on

  17. Metamaterials and Metasurfaces in THz Applications

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Malureanu, Radu; Zalkovskij, Maksim

    We present a set of terahertz optical components, such as linear and circular polarizers, absorbers, devices with enhanced transmittance, and single layer chiral systems based on metamaterials. Discussion covers design rules, fabrication and characterization.......We present a set of terahertz optical components, such as linear and circular polarizers, absorbers, devices with enhanced transmittance, and single layer chiral systems based on metamaterials. Discussion covers design rules, fabrication and characterization....

  18. Multispectral metamaterial absorber.

    Science.gov (United States)

    Grant, J; McCrindle, I J H; Li, C; Cumming, D R S

    2014-03-01

    We present the simulation, implementation, and measurement of a multispectral metamaterial absorber (MSMMA) and show that we can realize a simple absorber structure that operates in the mid-IR and terahertz (THz) bands. By embedding an IR metamaterial absorber layer into a standard THz metamaterial absorber stack, a narrowband resonance is induced at a wavelength of 4.3 μm. This resonance is in addition to the THz metamaterial absorption resonance at 109 μm (2.75 THz). We demonstrate the inherent scalability and versatility of our MSMMA by describing a second device whereby the MM-induced IR absorption peak frequency is tuned by varying the IR absorber geometry. Such a MSMMA could be coupled with a suitable sensor and formed into a focal plane array, enabling multispectral imaging.

  19. Tunable metamaterials fabricated by fiber drawing

    DEFF Research Database (Denmark)

    Fleming, Simon; Stefani, Alessio; Tang, Xiaoli

    2017-01-01

    We demonstrate a practical scalable approach to the fabrication of tunable metamaterials. Designed for terahertz (THz) wavelengths, the metamaterial is comprised of polyurethane filled with an array of indium wires using the well-established fiber drawing technique. Modification of the dimensions...

  20. Water: Promising Opportunities For Tunable All-dielectric Electromagnetic Metamaterials.

    Science.gov (United States)

    Andryieuski, Andrei; Kuznetsova, Svetlana M; Zhukovsky, Sergei V; Kivshar, Yuri S; Lavrinenko, Andrei V

    2015-08-27

    We reveal an outstanding potential of water as an inexpensive, abundant and bio-friendly high-refractive-index material for creating tunable all-dielectric photonic structures and metamaterials. Specifically, we demonstrate thermal, mechanical and gravitational tunability of magnetic and electric resonances in a metamaterial consisting of periodically positioned water-filled reservoirs. The proposed water-based metamaterials can find applications not only as cheap and ecological microwave devices, but also in optical and terahertz metamaterials prototyping and educational lab equipment.

  1. Dispersion management with metamaterials

    Science.gov (United States)

    Tassin, Philippe; Koschny, Thomas; Soukoulis, Costas M.

    2017-03-07

    An apparatus, system, and method to counteract group velocity dispersion in fibers, or any other propagation of electromagnetic signals at any wavelength (microwave, terahertz, optical, etc.) in any other medium. A dispersion compensation step or device based on dispersion-engineered metamaterials is included and avoids the need of a long section of specialty fiber or the need for Bragg gratings (which have insertion loss).

  2. Recent Progress in Terahertz Metasurfaces

    Science.gov (United States)

    Al-Naib, Ibraheem; Withayachumnankul, Withawat

    2017-09-01

    In the past decade, the concept of metasurfaces has gradually dominated the field of metamaterials owing to their fascinating optical properties and simple planar geometries. At terahertz frequencies, the concept has been driven further by the availability of advanced micro-fabrication technologies that deliver sub-micron accuracy, well below the terahertz wavelengths. Furthermore, terahertz spectrometers with high dynamic range and amplitude and phase sensitivity provide valuable information for the study of metasurfaces in general. In this paper, we review recent progress in terahertz metasurfaces mainly in the last 5 years. The first part covers nonuniform metasurfaces that perform beamforming in reflection and transmission. In addition, we briefly overview four different methodologies that can be utilized in realizing high-quality-factor metasurfaces. We also describe two recent approaches to tuning the frequency response of terahertz metasurfaces using graphene as an active medium. Finally, we provide a brief summary and outlook for future developments in this rapidly progressing field.

  3. Group Delay of High Q Antennas

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert Frølund

    2013-01-01

    become an issue, when working with high Q antennas, because of the steep phase shift over the frequency. In this paper, it is measured how large group delay variations can become, when going from a low Q antenna to a high Q antenna. The group delay of a low Q antenna is shown to be around 1.3 ns, whereas...... a high Q antenna has group delay of around 22 ns. It is due to this huge group delay variation characteristics of high Q antennas, that signal distortion might occur in the radio system with high Q antennas....

  4. Perfect terahertz absorber using fishnet based metafilm

    Energy Technology Data Exchange (ETDEWEB)

    Azad, Abul Kalam [Los Alamos National Laboratory; Shchegolkov, Dmitry Yu [Los Alamos National Laboratory; Chen, Houtong [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; Smirnova, E I [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory

    2009-01-01

    We present a perfect terahertz (THz) absorber working for a broad-angle of incidence. The two fold symmetry of rectangular fishnet structure allows either complete absorption or mirror like reflection depending on the polarization of incident the THz beam. Metamaterials enable the ability to control the electromagnetic wave in a unique fashion by designing the permittivity or permeability of composite materials with desired values. Although the initial idea of metamaterials was to obtain a negative index medium, however, the evolution of metamaterials (MMs) offers a variety of practically applicable devices for controlling electromagnetic wave such as tunable filters, modulators, phase shifters, compact antenna, absorbers, etc. Terahertz regime, a crucial domain of the electromagnetic wave, is suffering from the scarcity of the efficient devices and might take the advantage of metamaterials. Here, we demonstrate design, fabrication, and characterization of a terahertz absorber based on a simple fishnet metallic film separated from a ground mirror plane by a dielectric spacer. Such absorbers are in particular important for bolometric terahertz detectors, high sensitivity imaging, and terahertz anechoic chambers. Recently, split-ring-resonators (SRR) have been employed for metamaterial-based absorbers at microwave and THz frequencies. The experimental demonstration reveals that such absorbers have absorptivity close to unity at resonance frequencies. However, the downside of these designs is that they all employ resonators of rather complicated shape with many fine parts and so they are not easy to fabricate and are sensitive to distortions.

  5. Microelectromechanically tunable multiband metamaterial with preserved isotropy.

    Science.gov (United States)

    Pitchappa, Prakash; Ho, Chong Pei; Qian, You; Dhakar, Lokesh; Singh, Navab; Lee, Chengkuo

    2015-06-26

    We experimentally demonstrate a micromachined reconfigurable metamaterial with polarization independent characteristics for multiple resonances in terahertz spectral region. The metamaterial unit cell consists of eight out-of-plane deformable microcantilevers placed at each corner of an octagon ring. The octagon shaped unit cell geometry provides the desired rotational symmetry, while the out-of-plane movable cantilevers preserves the symmetry at different configurations of the metamaterial. The metamaterial is shown to provide polarization independent response for both electrical inductive-capacitive (eLC) resonance and dipolar resonance at all states of actuation. The proposed metamaterial has a switching range of 0.16 THz and 0.37 THz and a transmission intensity change of more than 0.2 and 0.7 for the eLC and dipolar resonances, respectively for both TE and TM modes. Further optimization of the metal layer thickness, provides an improvement of up to 80% modulation at 0.57 THz. The simultaneously tunable dual band isotropic metamaterial will enable the realization of high performance electro-optic devices that would facilitate numerous terahertz applications such as compressive terahertz imaging, miniaturized terahertz spectroscopy and next generation high speed wireless communication possible in the near future.

  6. Broadband terahertz generation of metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Liang; Wang, Jigang; Koschny, Thomas; Wegener, Martin; Soukoulis, Costas M.

    2017-06-20

    Provided are systems and methods to generate single-cycle THz pulses from a few tens of nanometers thin layer of split ring resonators (SRRs) via optical rectification of femtosecond laser pulses. The emitted THz radiation, with a spectrum ranging from about 0.1 to 4 THz, arises exclusively from pumping the magnetic-dipole resonance of SRRs around 200 THz. This resonant enhancement, together with pump polarization dependence and power scaling of the THz emission, underpins the nonlinearity from optically induced circulating currents in SRRs, with a huge effective nonlinear susceptibility of 0.8.times.10.sup.-16 m.sup.2/V that far exceeds surface nonlinearities of both thin films and bulk organic/inorganic crystals and sheet nonlinearities of non-centrosymmetric materials such as ZnTe.

  7. Direct Measurements of Terahertz Meta-atoms with Near-Field Emission of Terahertz Waves

    Science.gov (United States)

    Serita, Kazunori; Darmo, Juraj; Kawayama, Iwao; Murakami, Hironaru; Tonouchi, Masayoshi

    2017-09-01

    We present the direct measurements of terahertz meta-atoms, an elementary unit of metamaterials, by using locally generated terahertz waves in the near-field region. In contrast to a conventional far-field terahertz spectroscopy or imaging, our technique features the localized emission of coherent terahertz pulses on a sub-wavelength scale, which has a potential for visualizing details of dynamics of each meta-atom. The obtained data show the near-field coupling among the meta-atoms and the impact of the electric field distribution from the excited meta-atom to neighbor meta-atoms. The observable LC resonance response is enhanced with an increase of numbers of meta-atoms. Furthermore, our approach also has a potential for visualizing the individual mode of meta-atom at different terahertz irradiation spots. These data can help us to understand the important role of the meta-atom in metamaterials and develop the novel terahertz components and devices such as active terahertz metamaterial and compact, high-sensitive bio-sensor devices.

  8. Coding Metamaterials, Digital Metamaterials and Programming Metamaterials

    OpenAIRE

    Cui, Tie Jun; Qi, Mei Qing; Wan, Xiang; Zhao, Jie; Cheng, Qiang

    2014-01-01

    As artificial structures, metamaterials are usually described by macroscopic effective medium parameters, which are named as "analog metamaterials". Here, we propose "digital metamaterials" in two steps. Firstly, we present "coding metamaterials" that are composed of only two kinds of unit cells with 0 and {\\pi} phase responses, which we name as "0" and "1" elements. By coding "0" and "1" elements with controlled sequences (i.e., 1-bit coding), we can manipulate electromagnetic (EM) waves and...

  9. Frequency selective terahertz retroreflectors

    Science.gov (United States)

    Williams, Richard James

    The use of novel optical structures operating at terahertz frequencies in industrial and military applications continues to grow. Some of these novel structures include gratings, frequency selective surfaces, metamaterials and metasurfaces, and retroreflectors. A retroreflector is a device that exhibits enhanced backscatter by concentrating the reflected wave in the direction of the source. Retroreflectors have applications in a variety of diverse fields such as aviation, radar systems, antenna technology, communications, navigation, passive identification, and metrology due to their large acceptance angles and frequency bandwidth. This thesis describes the design, fabrication, and characterization of a retroreflector designed for terahertz frequencies and the incorporation of a frequency selective surface in order to endow the retroreflector with narrow-band frequency performance. The radar cross section of several spherical lens reflectors operating at terahertz frequencies was investigated. Spherical lens reflectors with diameters ranging from 2 mm to 8 mm were fabricated from fused silica ball lenses and their radar cross section was measured at 100 GHz, 160 GHz, and 350 GHz. Crossed-dipole frequency selective surfaces exhibiting band-pass characteristics at 350 GHz fabricated from 12 um-thick Nickel screens were applied to the apertures of the spherical lens reflectors. The radar cross section of the frequency selective retroreflectors was measured at 160 GHz and 350 GHz to demonstrate proof-of-concept of narrow-band terahertz performance.

  10. Experimental evidence of resonant effective permittivity in a dielectric metamaterial

    Science.gov (United States)

    Lepetit, T.; Akmansoy, É.; Ganne, J.-P.

    2011-01-01

    We designed and fabricated a dielectric metamaterial consisting of one set of high permittivity resonators. We experimentally showed that this metamaterial exhibits resonant effective permittivity, issued from the second mode of Mie resonances of these resonators. Therefore, metamaterials consisting of high permittivity resonators may provide either effective permeability or permittivity issued from the first two modes of Mie resonances, respectively. This ensures that all-dielectric metamaterials involving two sets of matched high permittivity resonators may exhibit negative index issued from these two modes, notably up to the terahertz domain.

  11. Subwavelength micropillar array terahertz lasers.

    Science.gov (United States)

    Krall, Michael; Brandstetter, Martin; Deutsch, Christoph; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Strasser, Gottfried; Unterrainer, Karl

    2014-01-13

    We report on micropillar-based terahertz lasers with active pillars that are much smaller than the emission wavelength. These micropillar array lasers correspond to scaled-down band-edge photonic crystal lasers forming an active photonic metamaterial. In contrast to photonic crystal lasers which use significantly larger pillar structures, lasing emission is not observed close to high-symmetry points in the photonic band diagram, but in the effective medium regime. We measure stimulated emission at 4 THz for micropillar array lasers with pillar diameters of 5 µm. Our results not only demonstrate the integration of active subwavelength optics in a terahertz laser, but are also an important step towards the realization of nanowire-based terahertz lasers.

  12. Metamaterial Sensors

    Directory of Open Access Journals (Sweden)

    Jing Jing Yang

    2013-01-01

    Full Text Available Metamaterials have attracted a great deal of attention due to their intriguing properties, as well as the large potential applications for designing functional devices. In this paper, we review the current status of metamaterial sensors, with an emphasis on the evanescent wave amplification and the accompanying local field enhancement characteristics. Examples of the sensors are given to illustrate the principle and the performance of the metamaterial sensor. The paper concludes with an optimistic outlook regarding the future of metamaterial sensor.

  13. Dielectric Metamaterials

    Science.gov (United States)

    2015-05-29

    Final Report  29 May 2015 Dielectric Metamaterials SRI Project P21340 ONR Contract N00014-12-1-0722 Prepared by: Srini Krishnamurthy...2 2. Theory of Metamaterials ....................................................................................................... 2 2.1...accurately assess the impact of various forms of disorder on metamaterials (MMs) (both dielectric and metal inclusions); and (5) identify designs

  14. Stealth metamaterial objects characterized in the far field by Radar Cross Section measurements

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Fan, K.; Strikwerda, A. C.

    Reflection spectra and radar cross sections (RCS) at terahertz frequencies are measured on structures incorporating absorbing metamaterials. Reduction of the RCS by the factor of 375 at the resonant frequencies is observed.......Reflection spectra and radar cross sections (RCS) at terahertz frequencies are measured on structures incorporating absorbing metamaterials. Reduction of the RCS by the factor of 375 at the resonant frequencies is observed....

  15. Integrated Ultra-High-Q Optical Resonator

    OpenAIRE

    Yang, Ki Youl; Oh, Dong Yoon; Lee, Seung Hoon; Yang, Qi-Fan; Yi, Xu; Vahala, Kerry

    2017-01-01

    Optical microcavities are compact, often chip-based devices, that are essential in technologies spanning frequency metrology to biosensing. They have also enabled new science in quantum information and cavity optomechanics. Performance requirements in subjects like cavity-QED and sensing have long placed emphasis on low-optical-loss (high-Q-factor) micrometer-scale resonators. However, an array of system-on-a-chip applications have emerged that also require millimeter-scale devices. To avoid ...

  16. Ground-plane-less bidirectional terahertz absorber based on omega resonators

    NARCIS (Netherlands)

    Balmakou, Alexei; Podalov, Maxim; Khakhomov, Sergei; Stavenga, Doekele; Semchenko, Igor

    2015-01-01

    We present a new ultrathin metamaterial that acts as a frequency-selective absorber of terahertz radiation. The absorber is a square array of pairs of omega-shaped micro-resonators made of high-ohmic-loss metal. The metamaterial provides significant suppression of transmitted and reflected radiation

  17. Fiber-Drawn Metamaterial for THz Waveguiding and Imaging

    Science.gov (United States)

    Atakaramians, Shaghik; Stefani, Alessio; Li, Haisu; Habib, Md. Samiul; Hayashi, Juliano Grigoleto; Tuniz, Alessandro; Tang, Xiaoli; Anthony, Jessienta; Lwin, Richard; Argyros, Alexander; Fleming, Simon C.; Kuhlmey, Boris T.

    2017-09-01

    In this paper, we review the work of our group in fabricating metamaterials for terahertz (THz) applications by fiber drawing. We discuss the fabrication technique and the structures that can be obtained before focusing on two particular applications of terahertz metamaterials, i.e., waveguiding and sub-diffraction imaging. We show the experimental demonstration of THz radiation guidance through hollow core waveguides with metamaterial cladding, where substantial improvements were realized compared to conventional hollow core waveguides, such as reduction of size, greater flexibility, increased single-mode operating regime, and guiding due to magnetic and electric resonances. We also report recent and new experimental work on near- and far-field THz imaging using wire array metamaterials that are capable of resolving features as small as λ/28.

  18. Fiber-Drawn Metamaterial for THz Waveguiding and Imaging

    DEFF Research Database (Denmark)

    Atakaramians, Shaghik; Stefani, Alessio; Li, Haisu

    2017-01-01

    In this paper, we review the work of our group in fabricating metamaterials for terahertz (THz) applications by fiber drawing. We discuss the fabrication technique and the structures that can be obtained before focusing on two particular applications of terahertz metamaterials, i.e., waveguiding...... and sub-diffraction imaging. We show the experimental demonstration of THz radiation guidance through hollow core waveguides with metamaterial cladding, where substantial improvements were realized compared to conventional hollow core waveguides, such as reduction of size, greater flexibility, increased...... single-mode operating regime, and guiding due to magnetic and electric resonances. We also report recent and new experimental work on near- and far-field THz imaging using wire array metamaterials that are capable of resolving features as small as λ/28....

  19. Bianisotropic metamaterial

    Energy Technology Data Exchange (ETDEWEB)

    El-Kady, Ihab F.; Reinke, Charles M.

    2017-07-18

    The topology of the elements of a metamaterial can be engineered from its desired electromagnetic constitutive tensor using an inverse group theory method. Therefore, given a desired electromagnetic response and a generic metamaterial elemental design, group theory is applied to predict the various ways that the element can be arranged in three dimensions to produce the desired functionality. An optimizer can then be applied to an electromagnetic modeling tool to fine tune the values of the electromagnetic properties of the resulting metamaterial topology.

  20. Graphene Based Terahertz Absorber Designed With Effective Surface Conductivity Approach

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Pizzocchero, Filippo; Booth, Tim

    Young field of terahertz (THz) science and technology demands new materials and devices, such as filters, modulators, polarization converters and absorbers. Graphene, a recently discovered single-atom-thick material, provides exciting properties for functional terahertz applications. Graphene...... in the working range. We demonstrate the possibility of the absorber bandwidth control with the metamaterial’s unit cell geometry. The results of fabrication and characterization of the THz graphene metamaterials based absorbers will be presented at the conference....

  1. Terahertz sources

    National Research Council Canada - National Science Library

    Shumyatsky, Pavel; Alfano, Robert R

    2011-01-01

    We present an overview and history of terahertz (THz) sources for readers of the biomedical and optical community for applications in physics, biology, chemistry, medicine, imaging, and spectroscopy...

  2. Optical Anapole Metamaterial.

    Science.gov (United States)

    Wu, Pin Chieh; Liao, Chun Yen; Savinov, Vassili; Chung, Tsung Lin; Chen, Wei Ting; Huang, Yao-Wei; Wu, Pei Ru; Chen, Yi-Hao; Liu, Ai-Qun; Zheludev, Nikolay I; Tsai, Din Ping

    2018-02-05

    The toroidal dipole is a localized electromagnetic excitation independent from the familiar magnetic and electric dipoles. It corresponds to currents flowing along minor loops of a torus. Interference of radiating induced toroidal and electric dipoles leads to anapole, a nonradiating charge-current configuration. Interactions of induced toroidal dipoles with electromagnetic waves have recently been observed in artificial media at microwave, terahertz, and optical frequencies. Here, we demonstrate a quasi-planar plasmonic metamaterial, a combination of dumbbell aperture and vertical split-ring resonator, that exhibits transverse toroidal moment and resonant anapole behavior in the optical part of the spectrum upon excitation with a normally incident electromagnetic wave. Our results prove experimentally that toroidal modes and anapole modes can provide distinct and physically significant contributions to the absorption and dispersion of slabs of matter in the optical part of the spectrum in conventional transmission and reflection experiments.

  3. Switchable tri-band THz polarizing rotator based on chiral metamaterials

    Science.gov (United States)

    Lu, Yuying; Li, Jining; Yao, Jianquan

    2018-01-01

    One kind of switchable, tri-band, terahertz linear polarizing rotator is presented in this paper, which consists of sandwiched metal chiral metamaterial structure composed of twisted electric field-coupled resonators in C4 symmetry and a VO2 film on substrate for active controlling. The polarizing rotation is switchable with the state change of VO2 from an insulator to metal. Simulated results consistently demonstrate that the switchable rotator exhibits extremely low loss, high polarization conversion ratio and optical activity at the three resonance frequencies. The influence of different geometric parameters of the chiral metamaterial structure is investigated to optimize the multiband rotating response of the polarizing rotator. This switchable terahertz metamaterial-based rotator has various potential applications in terahertz wave controlling and the terahertz functional devices.

  4. Hybrid metamaterial switching for manipulating chirality based on VO2 phase transition

    Science.gov (United States)

    Lv, T. T.; Li, Y. X.; Ma, H. F.; Zhu, Z.; Li, Z. P.; Guan, C. Y.; Shi, J. H.; Zhang, H.; Cui, T. J.

    2016-01-01

    Polarization manipulations of electromagnetic waves can be obtained by chiral and anisotropic metamaterials routinely, but the dynamic and high-efficiency modulations of chiral properties still remain challenging at the terahertz range. Here, we theoretically demonstrate a new scheme for realizing thermal-controlled chirality using a hybrid terahertz metamaterial with embedded vanadium dioxide (VO2) films. The phase transition of VO2 films in 90° twisted E-shaped resonators enables high-efficiency thermal modulation of linear polarization conversion. The asymmetric transmission of linearly polarized wave and circular dichroism simultaneously exhibit a pronounced switching effect dictated by temperature-controlled conductivity of VO2 inclusions. The proposed hybrid metamaterial design opens exciting possibilities to achieve dynamic modulation of terahertz waves and further develop tunable terahertz polarization devices. PMID:27000427

  5. Liquid crystal tunable metamaterial absorber.

    Science.gov (United States)

    Shrekenhamer, David; Chen, Wen-Chen; Padilla, Willie J

    2013-04-26

    We present an experimental demonstration of electronically tunable metamaterial absorbers in the terahertz regime. By incorporation of active liquid crystal into strategic locations within the metamaterial unit cell, we are able to modify the absorption by 30% at 2.62 THz, as well as tune the resonant absorption over 4% in bandwidth. Numerical full-wave simulations match well to experiments and clarify the underlying mechanism, i.e., a simultaneous tuning of both the electric and magnetic response that allows for the preservation of the resonant absorption. These results show that fundamental light interactions of surfaces can be dynamically controlled by all-electronic means and provide a path forward for realization of novel applications.

  6. Active graphene-silicon hybrid diode for terahertz waves.

    Science.gov (United States)

    Li, Quan; Tian, Zhen; Zhang, Xueqian; Singh, Ranjan; Du, Liangliang; Gu, Jianqiang; Han, Jiaguang; Zhang, Weili

    2015-05-11

    Controlling the propagation properties of the terahertz waves in graphene holds great promise in enabling novel technologies for the convergence of electronics and photonics. A diode is a fundamental electronic device that allows the passage of current in just one direction based on the polarity of the applied voltage. With simultaneous optical and electrical excitations, we experimentally demonstrate an active diode for the terahertz waves consisting of a graphene-silicon hybrid film. The diode transmits terahertz waves when biased with a positive voltage while attenuates the wave under a low negative voltage, which can be seen as an analogue of an electronic semiconductor diode. Here, we obtain a large transmission modulation of 83% in the graphene-silicon hybrid film, which exhibits tremendous potential for applications in designing broadband terahertz modulators and switchable terahertz plasmonic and metamaterial devices.

  7. Active graphene–silicon hybrid diode for terahertz waves

    Science.gov (United States)

    Li, Quan; Tian, Zhen; Zhang, Xueqian; Singh, Ranjan; Du, Liangliang; Gu, Jianqiang; Han, Jiaguang; Zhang, Weili

    2015-01-01

    Controlling the propagation properties of the terahertz waves in graphene holds great promise in enabling novel technologies for the convergence of electronics and photonics. A diode is a fundamental electronic device that allows the passage of current in just one direction based on the polarity of the applied voltage. With simultaneous optical and electrical excitations, we experimentally demonstrate an active diode for the terahertz waves consisting of a graphene–silicon hybrid film. The diode transmits terahertz waves when biased with a positive voltage while attenuates the wave under a low negative voltage, which can be seen as an analogue of an electronic semiconductor diode. Here, we obtain a large transmission modulation of 83% in the graphene–silicon hybrid film, which exhibits tremendous potential for applications in designing broadband terahertz modulators and switchable terahertz plasmonic and metamaterial devices. PMID:25959596

  8. Terahertz Techniques

    CERN Document Server

    Bründermann, Erik; Kimmitt, Maurice FitzGerald

    2012-01-01

    Research and development in the terahertz portion of the electromagnetic spectrum has expanded very rapidly during the past fifteen years due to major advances in sources, detectors and instrumentation. Many scientists and engineers are entering the field and this volume offers a comprehensive and integrated treatment of all aspects of terahertz technology. The three authors, who have been active researchers in this region over a number of years, have designed Terahertz Techniques to be both a general introduction to the subject and a definitive reference resource for all those involved in this exciting research area.

  9. Visible Spectrum Circular Dichroism in Extrinsic Chirality Metamaterials

    CERN Document Server

    Lee, Seoungjun; Feng, Cheng; Jiao, Jiao; Khan, Ashfaq; Li, Lin

    2012-01-01

    We present the new planar extrinsic chirality metamaterial (ECM) design that manifests giant circular dichroism (CD) in the visible spectrum range rather than usual near-infrared and terahertz range. Effects of incident beam angles and meta-molecules unit sizes on the CD spectrums were theoretically analyzed; Physical mechanism was illustrated in new figures of asymmetrical current excitation in neighboring unit cells.

  10. THz near-field Faraday imaging in hybrid metamaterials

    NARCIS (Netherlands)

    Kumar, N.; Strikwerda, A.C.; Fan, K.; Zhang, X.; Averitt, R.D.; Planken, P.C.M.; Adam, A.J.L.

    2012-01-01

    We report on direct measurements of the magnetic near-field of metamaterial split ring resonators at terahertz frequencies using a magnetic field sensitive material. Specifically, planar split ring resonators are fabricated on a single magneto-optically active terbium gallium garnet crystal.

  11. Terahertz deconvolution

    National Research Council Canada - National Science Library

    Walker, Gillian C; Bowen, John W; Labaune, Julien; Jackson, J-Bianca; Hadjiloucas, Sillas; Roberts, John; Mourou, Gerard; Menu, Michel

    2012-01-01

    The ability to retrieve information from different layers within a stratified sample using terahertz pulsed reflection imaging and spectroscopy has traditionally been resolution limited by the pulse width available...

  12. Using COMSOL Multiphysics Software to Model Anisotropic Dielectric and Metamaterial Effects in Folded-Waveguide Traveling-Wave Tube Slow-Wave Circuits

    Science.gov (United States)

    Starinshak, David P.; Smith, Nathan D.; Wilson, Jeffrey D.

    2008-01-01

    The electromagnetic effects of conventional dielectrics, anisotropic dielectrics, and metamaterials were modeled in a terahertz-frequency folded-waveguide slow-wave circuit. Results of attempts to utilize these materials to increase efficiency are presented.

  13. Terahertz scanning probe microscope

    NARCIS (Netherlands)

    Klapwijk, T.M.

    2014-01-01

    The invention provides aterahertz scanning probe microscope setup comprising (i) a terahertz radiation source configured to generate terahertz radiation; (ii) a terahertz lens configured to receive at least part of the terahertz radiation from the terahertz radiation source; (iii) a cantilever unit

  14. Experimental Realization of an Epsilon-Near-Zero Graded-Index Metalens at Terahertz Frequencies

    Science.gov (United States)

    Pacheco-Peña, Victor; Engheta, Nader; Kuznetsov, Sergei; Gentselev, Alexandr; Beruete, Miguel

    2017-09-01

    The terahertz band has been historically hindered by the lack of efficient generators and detectors, but a series of recent breakthroughs have helped to effectively close the "terahertz gap." A rapid development of terahertz technology has been possible thanks to the translation of revolutionary concepts from other regions of the electromagnetic spectrum. Among them, metamaterials stand out for their unprecedented ability to control wave propagation and manipulate electromagnetic response of matter. They have become a workhorse in the development of terahertz devices such as lenses, polarizers, etc., with fascinating features. In particular, epsilon-near-zero (ENZ) metamaterials have attracted much attention in the past several years due to their unusual properties such as squeezing, tunneling, and supercoupling where a wave traveling inside an electrically small channel filled with an ENZ medium can be tunneled through it, reducing reflections and coupling most of its energy. Here, we design and experimentally demonstrate an ENZ graded-index (GRIN) metamaterial lens operating at terahertz with a power enhancement of 16.2 dB, using an array of narrow hollow rectangular waveguides working near their cutoff frequencies. This is a demonstration of an ENZ GRIN device at terahertz and can open the path towards other realizations of similar devices enabling full quasioptical processing of terahertz signals.

  15. A Flexible Metamaterial Terahertz Perfect Absorber

    Science.gov (United States)

    Chen, X. R.; Zheng, Y. W.; Qin, L. M.; Wei, G. C.; Qin, Z. P.; Zhang, N. G.; Liu, K.; Li, S. Z.; Wang, S. X.

    2017-12-01

    We designed a THz matematerial absorber using metallic wires (MWs) and split resonant rings (SRRs). This matematerial absorber exhibits perfect absorption which up to 96% at 4.03 THz and is capable of wrapped around objects because of flexible polyimide dielectric substrate.

  16. Metamaterial Resonant Absorbers for Terahertz Sensing

    Science.gov (United States)

    2015-12-01

    5  Figure 4.  Example of the Basic Unit Cell Geometry for COMSOL ...Representation of a COMSOL Simulation with Initial Boundary Conditions...throughout this research using COMSOL Multiphysics software. The goal was to obtain geometric and physical configurations to maximize absorption of

  17. Strain Imaging Using Terahertz Waves and Metamaterials

    Science.gov (United States)

    2016-11-01

    NOT TO BE CONSTRUED AS AN OFFICIAL DEPARTMENT OF THE ARMY POSITION UNLESS SO DESIGNATED BY OTHER AUTHORIZED DOCUMENTS. TRADE NAMES USE...uu Polarization ............................................ 7 8. 500 μm Region of Sample MM6 for ux Polarization...8 9. 500 μm Region of Sample MM6 Mueller Matrix Prediction for ux Transmission

  18. Detuning effect study of High-Q Mobile Phone Antennas

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert F.

    2015-01-01

    Number of frequency bands that have to be covered by smart phones, are ever increasing. This broadband coverage can be obtained either by using a low-Q antenna or a high-Q tunable antenna. This study investigates high-Q antennas performance when placed in proximity of the user. This study...

  19. Implementation of an Optical Readout System for High-Sensitivity Terahertz Microelectromechanical Sensor Array

    Science.gov (United States)

    2014-09-01

    thin films and metamaterial structures. This effort culminated in the design and fabrication of novel microelectromechanical systems (MEMS) bi-material...applications, it has been reported that Golay cell micro arrays based on a graphene membrane have been developed with a responsivity of 400 nm/K [26...Grbovic, B. Kearney, and G. Karunasiri, “Microelectromechanical systems bimaterial terahertz sensor with integrated metamaterial absorber,” Opt. Lett

  20. Detection of Terahertz Radiation

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a system for detecting terahertz radiation, a camera device, and a method for detecting terahertz radiation.......The present invention relates to a system for detecting terahertz radiation, a camera device, and a method for detecting terahertz radiation....

  1. Feasibility of graphene CRLH metamaterial waveguides and leaky wave antennas

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Derrick A.; Itoh, Tatsuo [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Hon, Philip W. C. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); NG NEXT Nanophotonics and Plasmonics Laboratory, Northrop Grumman Aerospace Systems, Redondo Beach, California 90278 (United States); Williams, Benjamin S., E-mail: bswilliams@ucla.edu [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute (CNSI), University of California, Los Angeles, California 90095 (United States)

    2016-07-07

    The feasibility of composite right/left-handed (CRLH) metamaterial waveguides based upon graphene plasmons is demonstrated via numerical simulation. Designs are presented that operate in the terahertz frequency range along with their various dimensions. Dispersion relations, radiative and free-carrier losses, and free-carrier based tunability are characterized. Finally, the radiative characteristics are evaluated, along with its feasibility for use as a leaky-wave antenna. While CRLH waveguides are feasible in the terahertz range, their ultimate utility will require precise nanofabrication, and excellent quality graphene to mitigate free-carrier losses.

  2. Feasibility of graphene CRLH metamaterial waveguides and leaky wave antennas

    Science.gov (United States)

    Chu, Derrick A.; Hon, Philip W. C.; Itoh, Tatsuo; Williams, Benjamin S.

    2016-07-01

    The feasibility of composite right/left-handed (CRLH) metamaterial waveguides based upon graphene plasmons is demonstrated via numerical simulation. Designs are presented that operate in the terahertz frequency range along with their various dimensions. Dispersion relations, radiative and free-carrier losses, and free-carrier based tunability are characterized. Finally, the radiative characteristics are evaluated, along with its feasibility for use as a leaky-wave antenna. While CRLH waveguides are feasible in the terahertz range, their ultimate utility will require precise nanofabrication, and excellent quality graphene to mitigate free-carrier losses.

  3. Tunable waveguide bends with graphene-based anisotropic metamaterials

    KAUST Repository

    Chen, Zhao-xian

    2016-01-15

    We design tunable waveguide bends filled with graphene-based anisotropic metamaterials to achieve a nearly perfect bending effect. The anisotropic properties of the metamaterials can be described by the effective medium theory. The nearly perfect bending effect is demonstrated by finite element simulations of various structures with different bending curvatures and shapes. This effect is attributed to zero effective permittivity along the direction of propagation and matched effective impedance at the interfaces between the bending part and the dielectric waveguides. We envisage that the design will be applicable in the far-infrared and terahertz frequency ranges owing to the tunable dielectric responses of graphene.

  4. Application of Metamaterial in Perfect Absorber

    Directory of Open Access Journals (Sweden)

    ZHANG Yong

    2016-11-01

    Full Text Available Electromagnetic response of metamaterials is not only determined by its component materials but also the microstructure and arrangements of its resonant elements. The perfect absorber prepared by metamaterial (PMA can realize 100% absorption in specific frequency bands by designing reasonable structures of resonators. PMA can be applied in many domains, such as stealth material, frequency selective surface, terahertz imaging, micro antenna, intelligent communication, detection and regulation of electromagnetic wave because of its flexible designing, adjustable response, strong absorption, broad band, thin thickness, light mass. Based on the present study situation at home and abroad, we summarized the development, structure, preparation and test of PMA. In order to gain a more profound and comprehensive understanding on PMA, we also explored its trends, prospects and urgent problems. Proactive and intelligent PMA with multi functions and new PMA prepared by new material and new process are the future development trends.

  5. Single and multiband THz Metamaterial Polarizers

    CERN Document Server

    Sangala, Bagvanth Reddy; Deshmukh, Prathmesh; Surdi, Harshad; Rana, Goutam; Gopal, Achanta Venu; Prabhu, S S

    2015-01-01

    We report single and multiband linear polarizers for terahertz (THz) frequencies using cut-wire metamaterials (MM). The MMs are designed by finite element method, fabricated by electron beam lithography, and characterized by THz time-domain spectroscopy. The MM unit cells consist of single or multiple length cut-wire pads of gold on semi-insulating Gallium Arsenide for single or multiple band polarizers. The dependence of the resonance frequency of the single band polarizer on the length of the cut-wires is explained based a transmission line model.

  6. Identifying the perfect absorption of metamaterial absorbers

    Science.gov (United States)

    Duan, G.; Schalch, J.; Zhao, X.; Zhang, J.; Averitt, R. D.; Zhang, X.

    2018-01-01

    We present a detailed analysis of the conditions that result in unity absorption in metamaterial absorbers to guide the design and optimization of this important class of functional electromagnetic composites. Multilayer absorbers consisting of a metamaterial layer, dielectric spacer, and ground plane are specifically considered. Using interference theory, the dielectric spacer thickness and resonant frequency for unity absorption can be numerically determined from the functional dependence of the relative phase shift of the total reflection. Further, using transmission line theory in combination with interference theory we obtain analytical expressions for the unity absorption resonance frequency and corresponding spacer layer thickness in terms of the bare resonant frequency of the metamaterial layer and metallic and dielectric losses within the absorber structure. These simple expressions reveal a redshift of the unity absorption frequency with increasing loss that, in turn, necessitates an increase in the thickness of the dielectric spacer. The results of our analysis are experimentally confirmed by performing reflection-based terahertz time-domain spectroscopy on fabricated absorber structures covering a range of dielectric spacer thicknesses with careful control of the loss accomplished through water absorption in a semiporous polyimide dielectric spacer. Our findings can be widely applied to guide the design and optimization of the metamaterial absorbers and sensors.

  7. Theoretical Modeling and Electromagnetic Response of Complex Metamaterials

    Science.gov (United States)

    2017-03-06

    Index Semiconductor Metamaterials,” Physical Review B, Vol. 90, No. 3, 035138 (6 pages), July 29, 2014. [Fig. 5 from this paper has been selected...Alù, “ Graphene -Based Plasmonic Platform for Reconfigurable Terahertz Devices,” ACS Photonics, Vol. 1, No. 8, pp. 647-654, August 1, 2014. J11. A...Acoustically Modulated Surface Plasmons over a Graphene Monolayer,” Journal of Optics, Special Issue on Mid-IR and THz Photonics, Vol. 16, No. 9

  8. A comparison of graphene, superconductors and metals as conductors for metamaterials and plasmonics

    Energy Technology Data Exchange (ETDEWEB)

    Tassin, Philippe; Koschny, Thomas; Kafesaki, Maria; Soukoulis, Costas

    2012-03-30

    Recent advancements in metamaterials and plasmonics have promised a number of exciting applications, in particular at terahertz and optical frequencies. Unfortunately, the noble metals used in these photonic structures are not particularly good conductors at high frequencies, resulting in significant dissipative loss. Here, we address the question of what is a good conductor for metamaterials and plasmonics. For resonant metamaterials, we develop a figure-of-merit for conductors that allows for a straightforward classification of conducting materials according to the resulting dissipative loss in the metamaterial. Application of our method predicts that graphene and high-T{sub c} superconductors are not viable alternatives for metals in metamaterials. We also provide an overview of a number of transition metals, alkali metals and transparent conducting oxides. For plasmonic systems, we predict that graphene and high-T{sub c} superconductors cannot outperform gold as a platform for surface plasmon polaritons, because graphene has a smaller propagation length-to-wavelength ratio.

  9. Graphene metamaterial modulator for free-space thermal radiation.

    Science.gov (United States)

    Fan, Kebin; Suen, Jonathan; Wu, Xueyuan; Padilla, Willie J

    2016-10-31

    We proposed and demonstrated a new metamaterial architecture capable of high speed modulation of free-space space thermal infrared radiation using graphene. Our design completely eliminates channel resistance, thereby maximizing the electrostatic modulation speed, while at the same time effectively modulating infrared radiation. Experiment results verify that our device with area of 100 × 120 µm2 can achieve a modulation speed as high as 2.6 GHz. We further highlight the utility of our graphene metamaterial modulator by reconstructing a fast infrared signal using an equivalent time sampling technique. The graphene metamaterial modulator demonstrated here is not only limited to the thermal infrared, but may be scaled to longer infrared and terahertz wavelengths. Our work provides a path forward for realization of frequency selective and all-electronic high speed devices for infrared applications.

  10. Isotropic optical metamaterials

    DEFF Research Database (Denmark)

    Lederer, Falk; Rockstuhl, C.; Menzel, C.

    2010-01-01

    Metamaterial imaging applications require optical isotropy. We show that highly symmetric unit cells do not necessarily exhibit this property. We prove that the dispersion relation can be tailored using a supercell metama-terial. Such metamaterial exhibits an isotropic negative index close to -1...

  11. Large-scale fabrication of achiral plasmonic metamaterials with giant chiroptical response

    Directory of Open Access Journals (Sweden)

    Morten Slyngborg

    2016-06-01

    Full Text Available A variety of extrinsic chiral metamaterials were fabricated by a combination of self-ordering anodic oxidation of aluminum foil, nanoimprint lithography and glancing angle deposition. All of these techniques are scalable and pose a significant improvement to standard metamaterial fabrication techniques. Different interpore distances and glancing angle depositions enable the plasmonic resonance wavelength to be tunable in the range from UVA to IR. These extrinsic chiral metamaterials only exhibit significant chiroptical response at non-normal angles of incidence. This intrinsic property enables the probing of both enantoimeric structures on the same sample, by inverting the tilt of the sample relative to the normal angle. In biosensor applications this allows for more precise, cheap and commercialized devices. As a proof of concept two different molecules were used to probe the sensitivity of the metamaterials. These proved the applicability to sense proteins through non-specific adsorption on the metamaterial surface or through functionalized surfaces to increase the sensing sensitivity. Besides increasing the sensing sensitivity, these metamaterials may also be commercialized and find applications in surface-enhanced IR spectroscopy, terahertz generation and terahertz circular dichroism spectroscopy.

  12. High Quality Factor Fano-Resonant All-Dielectric Metamaterials

    CERN Document Server

    Yang, Yuanmu; Briggs, Dayrl P; Valentine, Jason

    2014-01-01

    Fano-resonant plasmonic metamaterials and nanostructures have become a major focus of the nanophotonics fields over the past several years due their ability to produce high quality factor (Q-factor) resonances. The origin of such resonances is the interference between a broad and narrow resonance, ultimately allowing suppression of radiative damping. However, Fano-resonant plasmonic structures still suffer non-radiative damping due to Ohmic loss, ultimately limiting the achievable Q-factors to values less than 10. Here, we report experimental demonstration of Fano-resonant silicon-based metamaterials that have a response that mimics the electromagnetically induced transparency (EIT) found in atomic systems. Due to extremely low absorption loss, a record-high Q-factor of 306 was experimentally observed. Furthermore, the unit cell of the metamaterial was designed with a feed-gap which results in strong local field enhancement in the surrounding medium resulting in strong light-matter interaction. This allows th...

  13. Metamaterial antennas: the most successful metamaterial technology?

    DEFF Research Database (Denmark)

    Breinbjerg, Olav

    2015-01-01

    The Thomson Reuters Web of Science™ lists more than 1500 journal articles related to metamaterial antennas from 2001 to 2015; this paper overviews some major objectives of such antennas.......The Thomson Reuters Web of Science™ lists more than 1500 journal articles related to metamaterial antennas from 2001 to 2015; this paper overviews some major objectives of such antennas....

  14. High-Q Bandpass Comb Filter for Mains Interference Extraction

    Directory of Open Access Journals (Sweden)

    Neycheva T.

    2009-12-01

    Full Text Available This paper presents a simple digital high-Q bandpass comb filter for power-line (PL or other periodical interference extraction. The filter concept relies on a correlated signal average resulting in alternating constructive and destructive spectrum interference i.e. the so-called comb frequency response. The presented filter is evaluated by Matlab simulations with real ECG signal contaminated with low amplitude PL interference. The made simulations show that this filter accurately extract the PL interference. It has high-Q notches only at PL odd harmonics and is appropriate for extraction of any kind of odd harmonic interference including rectangular shape. The filter is suitable for real-time operation with popular low-cost microcontrollers.

  15. Metamaterials beyond electromagnetism

    Science.gov (United States)

    Kadic, Muamer; Bückmann, Tiemo; Schittny, Robert; Wegener, Martin

    2013-12-01

    Metamaterials are rationally designed man-made structures composed of functional building blocks that are densely packed into an effective (crystalline) material. While metamaterials are mostly associated with negative refractive indices and invisibility cloaking in electromagnetism or optics, the deceptively simple metamaterial concept also applies to rather different areas such as thermodynamics, classical mechanics (including elastostatics, acoustics, fluid dynamics and elastodynamics), and, in principle, also to quantum mechanics. We review the basic concepts, analogies and differences to electromagnetism, and give an overview on the current state of the art regarding theory and experiment—all from the viewpoint of an experimentalist. This review includes homogeneous metamaterials as well as intentionally inhomogeneous metamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics. Examples are laminates, transient thermal cloaks, thermal concentrators and inverters, ‘space-coiling’ metamaterials, anisotropic acoustic metamaterials, acoustic free-space and carpet cloaks, cloaks for gravitational surface waves, auxetic mechanical metamaterials, pentamode metamaterials (‘meta-liquids’), mechanical metamaterials with negative dynamic mass density, negative dynamic bulk modulus, or negative phase velocity, seismic metamaterials, cloaks for flexural waves in thin plates and three-dimensional elastostatic cloaks.

  16. High-Q microwave photonic filter with a tuned modulator.

    Science.gov (United States)

    Capmany, J; Mora, J; Ortega, B; Pastor, D

    2005-09-01

    We propose the use of tuned electro-optic or electroabsorption external modulators to implement high-quality (high-Q) factor, single-bandpass photonic filters for microwave signals. Using this approach, we experimentally demonstrate a transversal finite impulse response with a Q factor of 237. This is to our knowledge the highest value ever reported for a passive finite impulse-response microwave photonic filter.

  17. High-Q Antennas with built-in coils

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Svendsen, Simon; Pedersen, Gert Frølund

    2014-01-01

    Efficiency and isolation, at low frequencies (700 MHz), are two of the most important metrics for successful multicommunication implementation. This paper presents an antenna concept, that exhibits a very high isolation between high-Q Tx and Rx antennas at 700 MHz. Furthermore, it is shown how...... coils can be integrating into the antenna structure for obtaining better efficiency. It is shown that by integrated coils into the antenna structure, the efficiency can be improved by 2dB for each antenna....

  18. Review of Recent Metamaterial Microfluidic Sensors.

    Science.gov (United States)

    Salim, Ahmed; Lim, Sungjoon

    2018-01-15

    Metamaterial elements/arrays exhibit a sensitive response to fluids yet with a small footprint, therefore, they have been an attractive choice to realize various sensing devices when integrated with microfluidic technology. Micro-channels made from inexpensive biocompatible materials avoid any contamination from environment and require only microliter-nanoliter sample for sensing. Simple design, easy fabrication process, light weight prototype, and instant measurements are advantages as compared to conventional (optical, electrochemical and biological) sensing systems. Inkjet-printed flexible sensors find their utilization in rapidly growing wearable electronics and health-monitoring flexible devices. Adequate sensitivity and repeatability of these low profile microfluidic sensors make them a potential candidate for point-of-care testing which novice patients can use reliably. Aside from degraded sensitivity and lack of selectivity in all practical microwave chemical sensors, they require an instrument, such as vector network analyzer for measurements and not readily available as a self-sustained portable sensor. This review article presents state-of-the-art metamaterial inspired microfluidic bio/chemical sensors (passive devices ranging from gigahertz to terahertz range) with an emphasis on metamaterial sensing circuit and microfluidic detection. We also highlight challenges and strategies to cope these issues which set future directions.

  19. Optical isotropic negative index metamaterials

    DEFF Research Database (Denmark)

    Menzel, Christoph; Paul, Thomas; Rockstuhl, Carsten

    2010-01-01

    Towards isotropic metamaterials, we analyze isofrequency surfaces of the dispersion relation of high symmetry metamaterials and show that they are optically not isotropic. We achieve instead isotropic metamaterials that consist of carefully designed multiple layers....

  20. Aperiodic-metamaterial-based absorber

    OpenAIRE

    Quanlong Yang; Xieyu Chen; Yanfeng Li; Xueqian Zhang; Yuehong Xu; Zhen Tian; Chunmei Ouyang; Jianqiang Gu; Jiaguang Han; Weili Zhang

    2017-01-01

    The periodic-metamaterial-based perfect absorber has been studied broadly. Conversely, if the unit cell in the metamaterial-based absorber is arranged aperiodically (aperiodic-metamaterial-based absorber), how does it perform? Inspired by this, here we present a systematic study of the aperiodic-metamaterial-based absorber. By investigating the response of metamaterial absorbers based on periodic, Fibonacci, Thue-Morse, and quasicrystal lattices, we found that aperiodic-metamaterial-based abs...

  1. Hybrid semiconductor-dielectric metamaterial modulation for switchable bi-directional THz absorbers

    Science.gov (United States)

    Le, Ly Nguyen; Thang, Nguyen Manh; Thuy, Le Minh; Tung, Nguyen Thanh

    2017-01-01

    There is an increasing interest for electromagnetic metamaterials that show mutable absorption properties with real-time and dynamic control. In this paper, we investigate a modulation of bi-directional metamaterial absorbers that is thermally switchable at terahertz frequencies. The metamaterial absorber is composed of symmetric hybrid semiconductor-dielectric cut-wire-pair structures, whose electromagnetic responses can be actively manipulated by utilizing an external heat source. As increasing the temperature of metamaterials from 300 to 350 K, we demonstrate that the magnetic resonance can be systematically blue-shifted and overlapped with the electric resonance, which is unaffectedly settled at about 0.8 THz. This superposition provides an effective mechanism to control the absorption intensity from 43% to nearly 95%. Finite integration simulation technique, standard retrieval method, and equivalent circuit model are employed to elaborate our idea.

  2. Near-field probing of Mie resonances in single TiO.sub.2./sub. microspheres at terahertz frequencies

    Czech Academy of Sciences Publication Activity Database

    Mitrofanov, O.; Dominec, Filip; Kužel, Petr; Reno, J.L.; Brener, I.; Chung, U.-C.; Elissalde, C.; Maglione, M.; Mounaix, P.

    2014-01-01

    Roč. 22, č. 19 (2014), s. 23034-23042 ISSN 1094-4087 R&D Projects: GA ČR(CZ) GA14-25639S EU Projects: European Commission(XE) 607521 - NOTEDEV Institutional support: RVO:68378271 Keywords : metamaterials * near-field microscopy * resonators * terahertz imaging Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.488, year: 2014

  3. [A Double Split Ring Terahertz Filter on Ploymide Substrate].

    Science.gov (United States)

    He, Jun; Zhang, Tie-jun; Xiong, Wei; Zhang, Bo; He, Ting; Shen, Jing-ling

    2015-11-01

    Metamaterials are artificial composites that acquire their electromagnetic properties from embeded subwavelength metalic structure. With proper design of metamaterials, numerrous intriguing phenomena that not exhibited naturally can be realized, such as invisible cloaking, perfect absorption, negative refractive index and so on. In recent years, With the development of THz technology, the extensive research onTHz metamaterials devices areattracting more and more attentions. Since silicon (Si) has a higher transmittance for THz wave, it is usually selected as substrate in metamaterials structure. However, Si has the shortcomings of hardness, not easy to bend, and fragile, which limit the application of THz metamaterials. In this work, we use polyimide as the substrate to overcome the shortcomings of the Si substrate. Polyimide is flexible, smooth, suitable for conventional lithography process and the THz transmittance can compete with that of the Si. Frist, we test the THz optical properties of polymide, and get the refractive index of 1.9, and the transmittance of 80%. Second, we design a double splits ring resonators (DSRRs), and study the properties of transmission by changing the THz incidence angle and curvature of the sample. We find the resonant amplitude and resonant frequencies are unchanged. Fabricating metamaterials structures on a thin plastic substrate is a possible way to extend plane surface filtering to curved surface filtering. Third, we try to make a broadband filter by stacking two samples, and the 181GHz bandwidth at 50% has been achieved. By stacking several plane plastic metamaterial layers with different resonance responses into a multi-layer structure, a broadband THz filter can be built. The broadband filter has the advantages of simple manufacture, obvious filtering effect, which provides a new idea for the production of terahertz band filter.

  4. High-Q gold and silicon nitride bilayer nanostrings

    Science.gov (United States)

    Biswas, T. S.; Suhel, A.; Hauer, B. D.; Palomino, A.; Beach, K. S. D.; Davis, J. P.

    2012-08-01

    Low-mass, high-Q, silicon nitride nanostrings are at the cutting edge of nanomechanical devices for sensing applications. Here we show that the addition of a chemically functionalizable gold overlayer does not adversely affect the Q of the fundamental out-of-plane mode. Instead the device retains its mechanical responsiveness while gaining sensitivity to molecular bonding. Furthermore, differences in thermal expansion within the bilayer give rise to internal stresses that can be electrically controlled. In particular, an alternating current (AC) excites resonant motion of the nanostring. This AC thermoelastic actuation is simple, robust, and provides an integrated approach to sensor actuation.

  5. Proton structure at high Q/sup 2/

    CERN Document Server

    Nagano, K

    2001-01-01

    The H1 and ZEUS experiments at HERA have measured e/sup +/p and e/sup -/p deep inelastic scattering cross sections at high Q/sup 2/ both for neutral and charged current interactions. Results are presented from data taken during the 1994-1997 (e/sup +/p) and 1998-April 1999 (e/sup -/p) running periods. Preliminary results by H1 from the e/sup +/p data taken during the recent July 1999-2000 running period are also presented.

  6. High Q-factor tunable superconducting HF circuit

    CERN Document Server

    Vopilkin, E A; Pavlov, S A; Ponomarev, L I; Ganitsev, A Y; Zhukov, A S; Vladimirov, V V; Letyago, A G; Parshikov, V V

    2001-01-01

    Feasibility of constructing a high Q-factor (Q approx 10 sup 5) mechanically tunable in a wide range of frequencies (12-63 MHz) vibration circuit of HF range was considered. The tunable circuit integrates two single circuits made using YBaCuO films. The circuit frequency is tuned by changing distance X (capacity) between substrates. Potentiality of using substrates of lanthanum aluminate, neodymium gallate and strontium titanate for manufacture of single circuits was considered. Q-factor of the circuit amounted to 68000 at resonance frequency of 6.88 MHz

  7. Metamaterial Demonstrates Both a High Refractive Index and Extremely Low Reflection in the 0.3-THz Band

    Science.gov (United States)

    Ishihara, Koki; Suzuki, Takehito

    2017-09-01

    Communication and imaging in the terahertz waveband have advanced rapidly in offering industrial applications. However, optical elements such as collimated lenses in the terahertz waveband are bulky compared with the wavelength due to the lack of naturally occurring substances with a high refractive index and low loss. It is essential to miniaturize optical elements in the terahertz waveband for industrial application. Metamaterials consisting of subwavelength structures can arbitrarily control permittivity and permeability and provide a range of refractive indices. Here, we demonstrate a metamaterial with both a high refractive index and extremely low reflection consisting of symmetrically aligned paired cut metal wires with 18,800 units on the front and back surfaces of a dielectric substrate. Measurements by terahertz time-domain spectroscopy (THz-TDS) confirm a high effective refractive index of 6.66 + j0.123, extremely low reflection power of 1.16%, and the unprecedented high figure of merit (FOM = | n real/ n imag|) of above 300 in the 0.3-THz band. Components with such specifications would enable miniature, high-performance optical elements in the terahertz waveband such as ultrathin flat antennas with high directivity. Further, the concept of the metamaterial with both a high refractive index and extremely low reflection potentially offers a wide range of attractive applications such as solid immersion lenses and cloaking devices.

  8. Graphene superstrates for metamaterials

    OpenAIRE

    Papasimakis, N.; Luo, Z.; Shen, Z.X.; De Angelis, F.; Di Fabrizio, E.; Nikolaenko, A.E.; Zheludev, N.I.

    2010-01-01

    The electromagnetic properties of a photonic metamaterial are dramatically modified by a graphene monolayer superstrate. The strong polarizability of the graphene layer combined with the Fano-type, resonant plasmonic modes supported by the metamaterial leads to substantial red-shift of the narrow metamaterial resonances. These frequency shifts translate to multi-fold increase in the measured transmission at a specific wavelength. In our experiments we used chemical vapor deposited (CVD) graph...

  9. Tunable and Memory Metamaterials

    Science.gov (United States)

    2015-12-02

    direction of the proposed work was to implement graphene -based metamaterials . A complimentary direction of research was focused on the development and...tunability of the electromagnetic response. The PI has investigated various schemes for implementation of graphene -based metamaterials . One outcome...of this work is that plasmonic-based approaches were established to be most beneficial for realization of graphene -based metamaterials [Nature

  10. Thermal Hyperbolic Metamaterials

    OpenAIRE

    Guo, Yu; Jacob, Zubin

    2013-01-01

    We explore the near-field radiative thermal energy transfer properties of hyperbolic metamaterials. The presence of unique electromagnetic states in a broad bandwidth leads to super-planckian thermal energy transfer between metamaterials separated by a nano-gap. We consider practical phonon-polaritonic metamaterials for thermal engineering in the mid-infrared range and show that the effect exists in spite of the losses, absorption and finite unit cell size. For thermophotovoltaic energy conve...

  11. High-Q MEMS Resonators for Laser Beam Scanning Displays

    Directory of Open Access Journals (Sweden)

    Ulrich Hofmann

    2012-06-01

    Full Text Available This paper reports on design, fabrication and characterization of high-Q MEMS resonators to be used in optical applications like laser displays and LIDAR range sensors. Stacked vertical comb drives for electrostatic actuation of single-axis scanners and biaxial MEMS mirrors were realized in a dual layer polysilicon SOI process. High Q-factors up to 145,000 have been achieved applying wafer level vacuum packaging technology including deposition of titanium thin film getters. The effective reduction of gas damping allows the MEMS actuator to achieve large amplitudes at high oscillation frequencies while driving voltage and power consumption can be minimized. Exemplarily shown is a micro scanner that achieves a total optical scan angle of 86 degrees at a resonant frequency of 30.8 kHz, which fulfills the requirements for HD720 resolution. Furthermore, results of a new wafer based glass-forming technology for fabrication of three dimensionally shaped glass lids with tilted optical windows are presented.

  12. Polarization-maintaining reflection-mode THz time-domain spectroscopy of a polyimide based ultra-thin narrow-band metamaterial absorber.

    Science.gov (United States)

    Astorino, Maria Denise; Fastampa, Renato; Frezza, Fabrizio; Maiolo, Luca; Marrani, Marco; Missori, Mauro; Muzi, Marco; Tedeschi, Nicola; Veroli, Andrea

    2018-01-31

    This paper reports the design, the microfabrication and the experimental characterization of an ultra-thin narrow-band metamaterial absorber at terahertz frequencies. The metamaterial device is composed of a highly flexible polyimide spacer included between a top electric ring resonator with a four-fold rotational symmetry and a bottom ground plane that avoids misalignment problems. Its performance has been experimentally demonstrated by a custom polarization-maintaining reflection-mode terahertz time-domain spectroscopy system properly designed in order to reach a collimated configuration of the terahertz beam. The dependence of the spectral characteristics of this metamaterial absorber has been evaluated on the azimuthal angle under oblique incidence. The obtained absorbance levels are comprised between 67% and 74% at 1.092 THz and the polarization insensitivity has been verified in transverse electric polarization. This offers potential prospects in terahertz imaging, in terahertz stealth technology, in substance identification, and in non-planar applications. The proposed compact experimental set-up can be applied to investigate arbitrary polarization-sensitive terahertz devices under oblique incidence, allowing for a wide reproducibility of the measurements.

  13. Metamaterials for Remote Generation of Spatially Controllable Two Dimensional Array of Microplasma

    Science.gov (United States)

    Singh, Pramod K.; Hopwood, Jeffrey; Sonkusale, Sameer

    2014-08-01

    Since the initial demonstration of negative refraction and cloaking using metamaterials, there has been enormous interest and progress in making practical devices based on metamaterials such as electrically small antennas, absorbers, modulators, detectors etc that span over a wide range of electromagnetic spectrum covering microwave, terahertz, infrared (IR) and optical wavelengths. We present metamaterial as an active substrate where each unit cell serves as an element for generation of plasma, the fourth state of matter. Sub-wavelength localization of incident electromagnetic wave energy, one of the most interesting properties of metamaterials is employed here for generating high electric field to ignite and sustain microscale plasmas. Frequency selective nature of the metamaterial unit cells make it possible to generate spatially localized microplasma in a large array using multiple resonators. A dual resonator topology is shown for the demonstration. Since microwave energy couples to the metamaterial through free space, the proposed approach is naturally wireless. Such spatially controllable microplasma arrays provide a fundamentally new material system for future investigations in novel applications, e.g. nonlinear metamaterials.

  14. Graphene hyperlens for terahertz radiation

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Chigrin, D.; Novitsky, Andrey

    2012-01-01

    We propose the structured graphene terahertz hyperlens that allows overcoming natural diffraction limit and resolving subwavelength features. The proposed hyperlens can have applications in terahertz spectroscopy and imaging.......We propose the structured graphene terahertz hyperlens that allows overcoming natural diffraction limit and resolving subwavelength features. The proposed hyperlens can have applications in terahertz spectroscopy and imaging....

  15. Vibrant times for mechanical metamaterials

    DEFF Research Database (Denmark)

    Christensen, Johan; Kadic, Muamer; Kraft, Oliver

    2015-01-01

    Metamaterials are man-made designer matter that obtains its unusual effective properties by structure rather than chemistry. Building upon the success of electromagnetic and acoustic metamaterials, researchers working on mechanical metamaterials strive at obtaining extraordinary or extreme...... mass density, negative modulus, pentamode, anisotropic mass density, Origami, nonlinear, bistable, and reprogrammable mechanical metamaterials....

  16. Metamaterials with Gain

    Science.gov (United States)

    Hess, Ortwin

    2012-02-01

    Nanoplasmonic metamaterials are the key to an extreme control of light and allow us to conceive materials with negative or vanishing refractive index. Indeed, metamaterials enable a multitude of exciting and useful applications, such as subwavelength focusing, invisibility cloaking, and ``trapped rainbow'' stopping of light. The realization of these materials has recently advanced from the microwave to the optical regime. However, at optical wavelengths, metamaterials may suffer from high dissipative losses owing to the metallic nature of their constituent nanoplasmonic meta-molecules. It is therefore not surprising that overcoming loss restrictions by gain is currently one of the most important topics in metamaterials' research. At the same time, providing gain on the nanoplasmonic (metamolecular) level opens up exciting new possibilities such as a whole new type of metamaterial nano-laser with a cavity length of about a tenth of the wavelength. The talk gives an overview of the state of the art of gain-enhanced metamaterials. Particular focus will be placed on nano-plasmonic metamaterials (such as double-fishnet metamaterials) with integrated laser dyes as gain medium. The successful compensation of loss by gain is demonstrated on the meta-molecular level. On the basis of a comprehensive, microscopic Maxwell-Bloch Langevin approach of spatio-temporal light amplification and lasing in gain-enhanced nanoplasmonic (negative-index) metamaterials a methodology based on the discrete Poynting's theorem is introduced that allows dynamic tracing of the flow of electromagnetic energy into and out of ``microscopic'' channels (light field, plasmons, gain medium). It is shown that steady-state amplification can be achieved in nanoplasmonic metamaterials. Finally, a complex spatio-temporal interplay of light-field and coherent absorption dynamics is revealed in the lasing dynamics of a nanoplasmonic gain-enhanced double-fishnet metamaterial.

  17. High-Q Supercavity Modes in Subwavelength Dielectric Resonators.

    Science.gov (United States)

    Rybin, Mikhail V; Koshelev, Kirill L; Sadrieva, Zarina F; Samusev, Kirill B; Bogdanov, Andrey A; Limonov, Mikhail F; Kivshar, Yuri S

    2017-12-15

    Recent progress in nanoscale optical physics is associated with the development of a new branch of nanophotonics exploring strong Mie resonances in dielectric nanoparticles with a high refractive index. The high-index resonant dielectric nanostructures form building blocks for novel photonic metadevices with low losses and advanced functionalities. However, unlike extensively studied cavities in photonic crystals, such dielectric resonators demonstrate low quality factors (Q factors). Here, we uncover a novel mechanism for achieving giant Q factors of subwavelength nanoscale resonators by realizing the regime of bound states in the continuum. In contrast to the previously suggested multilayer structures with zero permittivity, we reveal strong mode coupling and Fano resonances in homogeneous high-index dielectric finite-length nanorods resulting in high-Q factors at the nanoscale. Thus, high-index dielectric resonators represent the simplest example of nanophotonic supercavities, expanding substantially the range of applications of all-dielectric resonant nanophotonics and meta-optics.

  18. High Q, Miniaturized LCP-Based Passive Components

    KAUST Repository

    Shamim, Atif

    2014-10-16

    Various methods and systems are provided for high Q, miniaturized LCP-based passive components. In one embodiment, among others, a spiral inductor includes a center connection and a plurality of inductors formed on a liquid crystal polymer (LCP) layer, the plurality of inductors concentrically spiraling out from the center connection. In another embodiment, a vertically intertwined inductor includes first and second inductors including a first section disposed on a side of the LCP layer forming a fraction of a turn and a second section disposed on another side of the LCP layer. At least a portion of the first section of the first inductor is substantially aligned with at least a portion of the second section of the second inductor and at least a portion of the first section of the second inductor is substantially aligned with at least a portion of the second section of the first inductor.

  19. Digitally Programmable High-Q Voltage Mode Universal Filter

    Directory of Open Access Journals (Sweden)

    D. Singh

    2013-12-01

    Full Text Available A new low-voltage low-power CMOS current feedback amplifier (CFA is presented in this paper. This is used to realize a novel digitally programmable CFA (DPCFA using transistor arrays and MOS switches. The proposed realizations nearly allow rail-to-rail swing capability at all the ports. Class-AB output stage ensures low power dissipation and high current drive capability. The proposed CFA/ DPCFA operates at supply voltage of ±0.75 V and exhibits bandwidth better than 95 MHz. An application of the DPCFA to realize a novel voltage mode high-Q digitally programmable universal filter (UF is given. Performances of all the proposed circuits are verified by PSPICE simulation using TSMC 0.25μm technology parameters.

  20. Ultra-high-Q nanobeam cavity design in Diamond

    CERN Document Server

    Bayn, Igal; Kalish, Rafi

    2010-01-01

    A novel nanobeam design with a triangular cross-section is proposed. This design makes possible implementing nanocavities with improved optical properties. The dependence of a diamond-based cavity quality factor Q and mode volume Vm on geometry parameter space are studied via 3D FDTD computations. An ultra-high-Q cavity with Q\\aprox 2.51 \\times 10^6 and Vm=1.06 \\times ({\\lambda}/n)^3 is predicted. The mode preferential radiation is upward. The implications on the potential applications are discussed. The proposed nanobeam enables fabrication of the cavity without relying on a pre-existing free-standing diamond membrane as required in most previous approaches.

  1. Towards terahertz microscopy

    NARCIS (Netherlands)

    Van der Valk, N.C.J.

    2005-01-01

    Terahertz (=1012 Hz) radiation is a form of electromagnetic radiation that is at this moment used rarely for imaging purposes. However, there are indeed reasons to assume that imaging with terahertz radiation could be very useful. First, many materials, such as paper, plastics and clothing are

  2. Terahertz polarization imaging

    NARCIS (Netherlands)

    Van der Valk, N.C.J.; Van der Marel, W.A.M.; Planken, P.C.M.

    2005-01-01

    We present a new method to measure the polarization state of a terahertz pulse by using a modified electrooptic sampling setup. To illustrate the power of this method, we show two examples in which the knowledge of the polarization of the terahertz pulse is essential for interpreting the results:

  3. Mass Separation by Metamaterials

    Science.gov (United States)

    Restrepo-Flórez, Juan Manuel; Maldovan, Martin

    2016-02-01

    Being able to manipulate mass flow is critically important in a variety of physical processes in chemical and biomolecular science. For example, separation and catalytic systems, which requires precise control of mass diffusion, are crucial in the manufacturing of chemicals, crystal growth of semiconductors, waste recovery of biological solutes or chemicals, and production of artificial kidneys. Coordinate transformations and metamaterials are powerful methods to achieve precise manipulation of molecular diffusion. Here, we introduce a novel approach to obtain mass separation based on metamaterials that can sort chemical and biomolecular species by cloaking one compound while concentrating the other. A design strategy to realize such metamaterial using homogeneous isotropic materials is proposed. We present a practical case where a mixture of oxygen and nitrogen is manipulated using a metamaterial that cloaks nitrogen and concentrates oxygen. This work lays the foundation for molecular mass separation in biophysical and chemical systems through metamaterial devices.

  4. Isotropic Single Negative Metamaterials

    Directory of Open Access Journals (Sweden)

    P. Protiva

    2008-09-01

    Full Text Available This paper presents the application of simple, and therefore cheap, planar resonators for building 3D isotropic metamaterials. These resonators are: a broadside-coupled split ring resonator with a magnetic response providing negative permeability; an electric dipole terminated by a loop inductor together with a double H-shaped resonator with an electric response providing negative permittivity. Two kinds of 3D isotropic single negative metamaterials are reported. The first material consists of unit cells in the form of a cube bearing on its faces six equal planar resonators with tetrahedral symmetry. In the second material, the planar resonators boxed into spherical plastic shells and randomly distributed in a hosting material compose a real 3D volumetric metamaterial with an isotropic response. In both cases the metamaterial shows negative permittivity or permeability, according to the type of resonators that are used. The experiments prove the isotropic behavior of the cells and of the metamaterial specimens.

  5. Thermal hyperbolic metamaterials.

    Science.gov (United States)

    Guo, Yu; Jacob, Zubin

    2013-06-17

    We explore the near-field radiative thermal energy transfer properties of hyperbolic metamaterials. The presence of unique electromagnetic states in a broad bandwidth leads to super-planckian thermal energy transfer between metamaterials separated by a nano-gap. We consider practical phonon-polaritonic metamaterials for thermal engineering in the mid-infrared range and show that the effect exists in spite of the losses, absorption and finite unit cell size. For thermophotovoltaic energy conversion applications requiring energy transfer in the near-infrared range we introduce high temperature hyperbolic metamaterials based on plasmonic materials with a high melting point. Our work paves the way for practical high temperature radiative thermal energy transfer applications of hyperbolic metamaterials.

  6. Terahertz Spectroscopy and Imaging

    CERN Document Server

    Zeitler, Axel; Kuwata-Gonokami, Makoto

    2013-01-01

    "This book presents the current state of knowledge in the field of terahertz spectroscopy, providing a comprehensive source of information for beginners and experienced researchers alike whose interests lie in this area. The book aims to explain the fundamental physics that underpins terahertz  technology and to describe its key applications. Highlights of scientific research in the field of terahertz science are also outlined in some chapters, providing an overview as well as giving an insight into future directions for research.  Over the past decade terahertz spectroscopy has developed into one of the most rapidly growing areas of its kind, gaining an important impact across a wide range of scientific disciplines. Due to substantial advances in femtosecond laser technology, terahertz time-domain spectroscopy (THz-TDS) has established itself as the dominant spectroscopic technique for experimental scientists interested in measurements at this frequency range. In solids and liquids THz radiation is in reso...

  7. An electromechanically reconfigurable plasmonic metamaterial operating in the near-infrared.

    Science.gov (United States)

    Ou, Jun-Yu; Plum, Eric; Zhang, Jianfa; Zheludev, Nikolay I

    2013-04-01

    Current efforts in metamaterials research focus on attaining dynamic functionalities such as tunability, switching and modulation of electromagnetic waves. To this end, various approaches have emerged, including embedded varactors, phase-change media, the use of liquid crystals, electrical modulation with graphene and superconductors, and carrier injection or depletion in semiconductor substrates. However, tuning, switching and modulating metamaterial properties in the visible and near-infrared range remain major technological challenges: indeed, the existing microelectromechanical solutions used for the sub-terahertz and terahertz regimes cannot be shrunk by two to three orders of magnitude to enter the optical spectral range. Here, we develop a new type of metamaterial operating in the optical part of the spectrum that is three orders of magnitude faster than previously reported electrically reconfigurable metamaterials. The metamaterial is actuated by electrostatic forces arising from the application of only a few volts to its nanoscale building blocks-the plasmonic metamolecules-that are supported by pairs of parallel strings cut from a flexible silicon nitride membrane of nanoscale thickness. These strings, of picogram mass, can be driven synchronously to megahertz frequencies to electromechanically reconfigure the metamolecules and dramatically change the transmission and reflection spectra of the metamaterial. The metamaterial's colossal electro-optical response (on the order of 10(-5)-10(-6) m V(-1)) allows for either fast continuous tuning of its optical properties (up to 8% optical signal modulation at up to megahertz rates) or high-contrast irreversible switching in a device only 100 nm thick, without the need for external polarizers and analysers.

  8. A tunable hybrid metamaterial absorber based on vanadium oxide films

    Science.gov (United States)

    Wen, Qi-Ye; Zhang, Huai-Wu; Yang, Qing-Hui; Chen, Zhi; Long, Yang; Jing, Yu-Lan; Lin, Yuan; Zhang, Pei-Xin

    2012-06-01

    A tunable hybrid metamaterial absorber (MA) in the microwave band was designed, fabricated and characterized. The hybrid MA was realized by incorporating a VO2 film into the conventional resonant MA. By thermally triggering the insulator-metal phase transition of the VO2 film, the impedance match condition was broken and a deep amplitude modulation of about 63.3% to the electromagnetic wave absorption was achieved. A moderate blue-shift of the resonance frequency was observed which is promising for practical applications. This VO2-based MA exhibits many advantages such as strong tunability, frequency agility, simple fabrication and ease of scaling to the terahertz band.

  9. Equal-potential interpretation of electrically induced resonances in metamaterials

    DEFF Research Database (Denmark)

    Peng, Liang; Mortensen, N. Asger

    2011-01-01

    We propose a general description of electrically induced resonances (EIR) in metamaterials (MMs) comprising subwavelength unit cells. Based on classical electrodynamics, we found that EIR is governed by an equal-potential effect. Our theory accounts for the EIR phenomena and can give a renewed...... definition of the effective electric field and hence effective permittivity for MMs made of either dielectrics or metals as well as combinations thereof. The EIR, inherent to the periodic structures, may be the unifying origin of recently observed anomalous electromagnetic phenomena, e.g. the enhanced...... transmission, the suppressed transmission and the enhanced absorption by a variety of metal film structures in the terahertz range....

  10. Polarization-insensitive FSS-based perfect metamaterial absorbers for GHz and THz frequencies

    Science.gov (United States)

    Sabah, Cumali; Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Akgol, Oguzhan

    2014-04-01

    New perfect frequency selective surface (FSS) metamaterial absorbers (MAs) based on resonator with dielectric configuration are numerically presented and investigated for both microwave and terahertz frequency ranges. Also, to verify the behaviors of the FSS MAs, one of the MAs is experimentally analyzed and tested in the microwave frequency range. Suggested FSS MAs have simple configuration which introduces flexibility to adjust their FSS metamaterial properties and to rescale the structure easily for any desired frequency range. There is no study which simultaneously includes microwave and terahertz absorbers in a single design in the literature. Besides, numerical simulations verify that the FSS MAs could achieve very high absorption levels at wide angles of incidence for both transverse electric and transverse magnetic waves. The proposed FSS MAs and their variations enable many potential application areas in radar systems, communication, stealth technologies, and so on.

  11. Dichroism, chirality, and polarization eigenstates in Babinet nanoslot-dimer membrane metamaterials

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Chigrin, Dmitry N.; Kremers, Christian

    2013-01-01

    We present a detailed theoretical description of the optical properties of planar metamaterials comprising a metal membrane patterned with openings (microslots) arranged in closely located couples (dimers). Using the covariant coupled-dipole approach, the effective material tensors of such a meta...... numerical simulations is demonstrated. The results obtained are promising for the design of thin-film frequency selective polarization shapers for terahertz waves....

  12. Planar Holographic Metasurfaces for Terahertz Focusing

    Science.gov (United States)

    Kuznetsov, Sergei A.; Astafev, Mikhail A.; Beruete, Miguel; Navarro-Cía, Miguel

    2015-01-01

    Scientists and laymen alike have always been fascinated by the ability of lenses and mirrors to control light. Now, with the advent of metamaterials and their two-dimensional counterpart metasurfaces, such components can be miniaturized and designed with additional functionalities, holding promise for system integration. To demonstrate this potential, here ultrathin reflection metasurfaces (also called metamirrors) designed for focusing terahertz radiation into a single spot and four spaced spots are proposed and experimentally investigated at the frequency of 0.35 THz. Each metasurface is designed using a computer-generated spatial distribution of the reflection phase. The phase variation within 360 deg is achieved via a topological morphing of the metasurface pattern from metallic patches to U-shaped and split-ring resonator elements, whose spectral response is derived from full-wave electromagnetic simulations. The proposed approach demonstrates a high-performance solution for creating low-cost and lightweight beam-shaping and beam-focusing devices for the terahertz band.

  13. Metamaterials and wave control

    CERN Document Server

    Lheurette, Eric

    2013-01-01

    Since the concept was first proposed at the end of the 20th Century, metamaterials have been the subject of much research and discussion throughout the wave community. More than 10 years later, the number of related published articles is increasing significantly. Onthe one hand, this success can be attributed to dreams of new physical objects which are the consequences of the singular properties of metamaterials. Among them, we can consider the examples of perfect lensing and invisibility cloaking. On other hand,metamaterials also provide new tools for the design of well-known wave functions s

  14. Passive THz metamaterials

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Malureanu, Radu; Zalkovskij, Maksim

    2012-01-01

    . Our interest lies in metamaterials for a broad spectrum of linear properties in operations with THz waves, such as linear and circular polarizers, absorbers and devices with enhanced transmittivity, single layer dichroic and chiral systems. All the three steps (modelling, fabrication......In this work we present our activities in the fabrication and characterization of passive THz metamaterials. We use two fabrication processes to develop metamaterials either as free-standing metallic membranes or patterned metallic multi-layers on the substrates to achieve different functionalities...

  15. Superconducting metamaterials and qubits

    Science.gov (United States)

    Plourde, B. L. T.; Wang, Haozhi; Rouxinol, Francisco; LaHaye, M. D.

    2015-05-01

    Superconducting thin-film metamaterial resonators can provide a dense microwave mode spectrum with potential applications in quantum information science. We report on the fabrication and low-temperature measurement of metamaterial transmission-line resonators patterned from Al thin films. We also describe multiple approaches for numerical simulations of the microwave properties of these structures, along with comparisons with the measured transmission spectra. The ability to predict the mode spectrum based on the chip layout provides a path towards future designs integrating metamaterial resonators with superconducting qubits.

  16. Metamaterials Application in Sensing

    Directory of Open Access Journals (Sweden)

    Hui Sun

    2012-02-01

    Full Text Available Metamaterials are artificial media structured on a size scale smaller than wavelength of external stimuli, and they can exhibit a strong localization and enhancement of fields, which may provide novel tools to significantly enhance the sensitivity and resolution of sensors, and open new degrees of freedom in sensing design aspect. This paper mainly presents the recent progress concerning metamaterials-based sensing, and detailedly reviews the principle, detecting process and sensitivity of three distinct types of sensors based on metamaterials, as well as their challenges and prospects. Moreover, the design guidelines for each sensor and its performance are compared and summarized.

  17. A Metamaterial-Inspired Approach to RF Energy Harvesting

    Science.gov (United States)

    Fowler, Clayton; Zhou, Jiangfeng

    2016-03-01

    We demonstrate an RF energy harvesting rectenna design based on a metamaterial perfect absorber (MPA). With the embedded Schottky diodes, the rectenna converts captured RF energy to DC currents. The Fabry-Perot cavity resonance of the MPA greatly improves the amount of energy captured and hence improves the rectification efficiency. Furthermore, the FP resonance exhibits a high Q-factor and significantly increases the voltage across the Schottky diodes. This leads to a factor of 16 improvement of RF-DC conversion efficiency at ambient intensity level.

  18. Macroscopic quantum electrodynamics of high-Q cavities

    Energy Technology Data Exchange (ETDEWEB)

    Khanbekyan, Mikayel

    2009-10-27

    In this thesis macroscopic quantum electrodynamics in linear media was applied in order to develop an universally valid quantum theory for the description of the interaction of the electromagnetic field with atomic sources in high-Q cavities. In this theory a complete description of the characteristics of the emitted radiation is given. The theory allows to show the limits of the applicability of the usually applied theory. In order to establish an as possible generally valid theory first the atom-field interaction was studied in the framework of macroscopic quantum electrodynamics in dispersive and absorptive media. In order to describe the electromagnetic field from Maxwell's equations was started, whereby the noise-current densities, which are connected with the absorption of the medium, were included. The solution of these equations expresses the electromagnetic field variables by the noise-current densities by means of Green's tensor of the macroscopic Maxwell equations. The explicit quantization is performed by means of the noise-current densities, whereby a diagonal Hamiltonian is introduced, which then guarantees the time development according to Maxwell's equation and the fulfillment of the fundamental simultaneous commutation relations of the field variables. In the case of the interaction of the medium-supported field with atoms the Hamiltonian must be extended by atom-field interactions energies, whereby the canonical coupling schemes of the minimal or multipolar coupling can be used. The dieelectric properties of the material bodies as well as their shape are coded in the Green tensor of the macroscopic Maxwell equations. As preparing step first the Green tensor was specified in order to derive three-dimensional input-output relations for the electromagnetic field operators on a plane multilayer structure. Such a general dewscription of the electromagnetic field allows the inclusion both of dispersion and absorption of the media and the

  19. Intrinsically polarized elastic metamaterial

    Science.gov (United States)

    Bilal, Osama; Suesstrunk, Roman; Huber, Sebastian; Daraio, Chiara

    Mechanical metamaterials, with periodically repeating basic building blocks in space, expand the envelope of possible properties of matter. Metamaterials harness their effective properties through structure rather than chemical composition. Successful implementations of such materials enabled the realization of ultrastiff-utralight materials, negative Poisson ratio materials, and fluid-like solids. In this work, we theoretically analyze and experimentally implement a new design principle for mechanical metamaterials. By combining states of self-stress, topological invariants and additive manufacturing techniques, we realize a new class of three-dimensional mechanical metamaterials with polar elasticity. The fabricated specimens show, at two of its opposing faces along the same axis, an asymmetric elastic response (i.e., soft on one face and harder on the other). We design our lattice to retain angular dependency to a perpendicular load, providing a direct experimental observation of nodal Weyl lines.

  20. Blackbody metamaterial lasers

    KAUST Repository

    Liu, Changxu

    2015-01-01

    We investigate both theoretically and experimentally a new type of laser, which exploits a broadband light "condensation" process sustained by the stimulated amplification of an optical blackbody metamaterial. © 2014 Optical Society of America.

  1. Metamaterials critique and alternatives

    CERN Document Server

    Munk, Ben A

    2009-01-01

    A Convincing and Controversial Alternative Explanation of Metamaterials with a Negative Index of Refraction In a book that will generate both support and controversy, one of the world's foremost authorities on periodic structures addresses several of the current fashions in antenna design-most specifically, the popular subject of double negative metamaterials. Professor Munk provides a comprehensive theoretical electromagnetic investigation of the issues and concludes that many of the phenomena claimed by researchers may be impossible. While denying the existence of negative refractio

  2. Resonant dielectric metamaterials

    Science.gov (United States)

    Loui, Hung; Carroll, James; Clem, Paul G; Sinclair, Michael B

    2014-12-02

    A resonant dielectric metamaterial comprises a first and a second set of dielectric scattering particles (e.g., spheres) having different permittivities arranged in a cubic array. The array can be an ordered or randomized array of particles. The resonant dielectric metamaterials are low-loss 3D isotropic materials with negative permittivity and permeability. Such isotropic double negative materials offer polarization and direction independent electromagnetic wave propagation.

  3. Superconducting metamaterial transmission line

    Science.gov (United States)

    Rouxinol, Francisco; Wang, Haozhi; Plourde, B. L. T.

    2014-03-01

    Left-handed metamaterials are artificial composite structures with unusual properties. Such systems have a wide range of potential applications in photonics. We are developing transmission lines composed of superconducting metamaterials using thin-film lumped circuit elements. Such structures allow for the possibility of generating novel transmission spectra with a high density of modes in some frequency ranges and stop-bands in others. We discuss possible couplings of these lines to superconducting qubits in circuit QED architectures.

  4. Superconducting metamaterials and qubits

    OpenAIRE

    Plourde, B. L. T.; Wang, Haozhi; Rouxinol, Francisco; LaHaye, M. D.

    2015-01-01

    Superconducting thin-film metamaterial resonators can provide a dense microwave mode spectrum with potential applications in quantum information science. We report on the fabrication and low-temperature measurement of metamaterial transmission-line resonators patterned from Al thin films. We also describe multiple approaches for numerical simulations of the microwave properties of these structures, along with comparisons with the measured transmission spectra. The ability to predict the mode ...

  5. Magnetic graphene metamaterial

    OpenAIRE

    Papasimakis, N.; Thongrattanasiri, S.; Zheludev, N.I.; García de Abajo, F.J.

    2013-01-01

    Graphene has emerged as a novel plasmonic material with advantageous properties for metamaterial design, such as highly confined plasmons and fast electrical tuning by carrier injection. Here, we predict strong magnetic dipole response by graphene split nanorings at THz frequencies allowing to achieve metamaterials with a high degree of field confinement (~ one hundredth of the excitation wavelength) that is not attainable by using thin layers of conventional noble metals.

  6. Nanoscale Terahertz Emission Spectroscopy

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Kim, Hyewon; Colvin, Vicki L.

    By utilizing plasmonic coupling to an AFM probe, we demonstrate Laser Terahertz Emission Nanoscopy (LTEN) with sub-20 nm resolution. We demonstrate the resolution by imaging a single gold nanorod on an InAs substrate.......By utilizing plasmonic coupling to an AFM probe, we demonstrate Laser Terahertz Emission Nanoscopy (LTEN) with sub-20 nm resolution. We demonstrate the resolution by imaging a single gold nanorod on an InAs substrate....

  7. Optomechanical soft metamaterials

    Science.gov (United States)

    Peng, Xiangjun; He, Wei; Liu, Yifan; Xin, Fengxian; Lu, Tian Jian

    2017-06-01

    We present a new type of optomechanical soft metamaterials, which is different from conventional mechanical metamaterials, in that they are simple isotropic and homogenous materials without resorting to any complex nano/microstructures. This metamaterial is unique in the sense that its responses to uniaxial forcing can be tailored by programmed laser inputs to manifest different nonlinear constitutive behaviors, such as monotonic, S-shape, plateau, and non-monotonic snapping performance. To demonstrate the novel metamaterial, a thin sheet of soft material impinged by two counterpropagating lasers along its thickness direction and stretched by an in-plane tensile mechanical force is considered. A theoretical model is formulated to characterize the resulting optomechanical behavior of the thin sheet by combining the nonlinear elasticity theory of soft materials and the optical radiation stress theory. The optical radiation stresses predicted by the proposed model are validated by simulations based on the method of finite elements. Programmed optomechanical behaviors are subsequently explored using the validated model under different initial sheet thicknesses and different optical inputs, and the first- and second-order tangential stiffness of the metamaterial are used to plot the phase diagram of its nonlinear constitutive behaviors. The proposed optomechanical soft metamaterial shows great potential in biological medicine, microfluidic manipulation, and other fields.

  8. Chalcogenide glass metamaterial optical switch

    OpenAIRE

    Sámson, Z.L; MacDonald, K. F.; De Angelis, F.; ADAMO, G.; Knight, K; Huang, C. C.; Hewak, D W; Di Fabrizio, E.; Zheludev, N. I.

    2009-01-01

    The technology behind rewritable optical disks offers a new switching paradigm for metamaterials. A switch comprising resonant plasmonic metamaterial and electro-optic chalcogenide glass layers provides 75% optical transmission modulation in a device of subwavelength thickness

  9. Mechanical metamaterials: When size matters

    Science.gov (United States)

    Kadic, Muamer; Frenzel, Tobias; Wegener, Martin

    2018-01-01

    That the unit cell of a metamaterial can't be considered vanishingly small like in ordinary crystals has long been deemed more burden than opportunity. The emergence of a characteristic length scale in metamaterial chains may change that trend.

  10. Thermal Loss of High-Q Antennas in Time Domain vs. Frequency Domain Solver

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert Frølund

    2014-01-01

    High-Q structures pose great challenges to their loss simulations in Time Domain Solvers (TDS). Therefore, in this work the thermal loss of high-Q antennas is calculated both in TDS and Frequency Domain Solver (FDS), which are then compared with each other and with the actual measurements....... The thermal loss calculation in FDS is shown to be more accurate for high-Q antennas....

  11. Direct modeling of near field thermal radiation in a metamaterial.

    Science.gov (United States)

    Lu, Dawei; Das, Ananda; Park, Wounjhang

    2017-05-29

    The study of near field thermal radiation is gaining renewed interest thanks in part to their great potential in energy harvesting applications. It is well known that plasmonic or polaritonic materials exhibit strongly enhanced fields near the surface, but it is not trivial to quantitatively predict their impact on thermal radiation intensity in the near field. In this paper, we present a case study for a metamaterial that supports a surface plasmon mode in the terahertz region and consequently exhibits strongly enhanced near field thermal radiation at the plasmon resonance frequency. We implemented a finite-difference time-domain method that thermally excites the metamaterial with randomly fluctuating dipoles according to the fluctuation-dissipation theorem. The calculated thermal radiation from the metamaterial was then compared with the case of optical excitation by the plane wave incident on the metamaterial surface. The optical excitation couples only to the mode that satisfies the momentum matching condition while thermal excitation is not bound by it. As a result, the near field thermal radiation exhibits substantial differences compared to the optically excited surface plasmon modes. Under thermal excitation, the near field intensity at 1 µm away from metal surface of the metamaterial reaches a maximum enhancement of 43 fold over the far field at the frequency of the Brillouin zone boundary mode while the near field intensity under optical excitation reaches a maximum enhancement of 24 fold at the frequency of the Brillouin zone center mode. In addition, the peak near field intensity under thermal excitation shows a 4-fold enhancement over blackbody radiation with linear polarization radiation in the far field. The ability to precisely predict the local field intensity under thermal excitation is critical to the development of advanced energy devices that take advantage of this near field enhancement and could lead to the development of new generation of

  12. Metamaterial electromagnetic wave absorbers.

    Science.gov (United States)

    Watts, Claire M; Liu, Xianliang; Padilla, Willie J

    2012-06-19

    The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch-the metamaterial perfect absorber (MPA)-has garnered interest due to the fact that it can achieve unity absorptivity of electromagnetic waves. Since its first experimental demonstration in 2008, the MPA has progressed significantly with designs shown across the electromagnetic spectrum, from microwave to optical. In this Progress Report we give an overview of the field and discuss a selection of examples and related applications. The ability of the MPA to exhibit extreme performance flexibility will be discussed and the theory underlying their operation and limitations will be established. Insight is given into what we can expect from this rapidly expanding field and future challenges will be addressed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Active nanoplasmonic metamaterials

    Science.gov (United States)

    Hess, O.; Pendry, J. B.; Maier, S. A.; Oulton, R. F.; Hamm, J. M.; Tsakmakidis, K. L.

    2012-07-01

    Optical metamaterials and nanoplasmonics bridge the gap between conventional optics and the nanoworld. Exciting and technologically important capabilities range from subwavelength focusing and stopped light to invisibility cloaking, with applications across science and engineering from biophotonics to nanocircuitry. A problem that has hampered practical implementations have been dissipative metal losses, but the efficient use of optical gain has been shown to compensate these and to allow for loss-free operation, amplification and nanoscopic lasing. Here, we review recent and ongoing progress in the realm of active, gain-enhanced nanoplasmonic metamaterials. On introducing and expounding the underlying theoretical concepts of the complex interaction between plasmons and gain media, we examine the experimental efforts in areas such as nanoplasmonic and metamaterial lasers. We underscore important current trends that may lead to improved active imaging, ultrafast nonlinearities on the nanoscale or cavity-free lasing in the stopped-light regime.

  14. Seismic auxetic metamaterials as novel earthquake protections

    CERN Document Server

    Ungureanu, Bogdan; Enoch, Stefan; Brûlé, Stéphane; Guenneau, Sébastien

    2015-01-01

    We propose that wave propagation through a class of elastodynamic metamaterials opens unprecedented avenues in seismic wave protection based on spectral properties of auxetic metamaterials. The elastic parameters of these metamaterials, like the Poisson ratio {\

  15. Terahertz beam switching by electrical control of graphene-enabled tunable metasurface.

    Science.gov (United States)

    Zhang, Yin; Feng, Yijun; Zhao, Junming; Jiang, Tian; Zhu, Bo

    2017-10-26

    Controlling the terahertz wave, especially the dynamical and full control of terahertz wavefront, is highly demanded due to the increasing development of practical devices and application systems. Recently considerable efforts have been made to fill the 'terahertz gap' with the help of artificial metamaterial or metasurface incorporated with graphene material. Here, we propose a scheme to design tunable metasurface consisting of metallic patch array on a grounded polymer substrate embedded with graphene layers to electrically control the electromagnetic beam reflection at terahertz frequency. By adjusting geometric dimension of the patch elements, 360 degree reflection phase range may be achieved, thus abrupt phase shifts can be introduced along the metasurface for tailoring the reflected wavefront. Moreover, the reflective phase gradient over the metasurface can be switched between 90 and 360 degree by controlling the Fermi energy of the embedded graphene through voltage biasing, hence dynamically switching the reflective beam directions. Numerical simulations demonstrate that either single beam or dual beam dynamically switching between normal and oblique reflection angles can be well attained at working frequency. The proposed approach will bring much freedom in the design of beam manipulation devices and may be applied to terahertz radiation control.

  16. Conformal dual-band near-perfectly absorbing mid-infrared metamaterial coating.

    Science.gov (United States)

    Jiang, Zhi Hao; Yun, Seokho; Toor, Fatima; Werner, Douglas H; Mayer, Theresa S

    2011-06-28

    Metamaterials offer a new approach to create surface coatings with highly customizable electromagnetic absorption from the microwave to the optical regimes. Thus far, efficient metamaterial absorbers have been demonstrated at microwave frequencies, with recent efforts aimed at much shorter terahertz and infrared wavelengths. The present infrared absorbers have been constructed from arrays of nanoscale metal resonators with simple circular or cross-shaped geometries, which provide a single band response. In this paper, we demonstrate a conformal metamaterial absorber with a narrow band, polarization-independent absorptivity of >90% over a wide ±50° angular range centered at mid-infrared wavelengths of 3.3 and 3.9 μm. The highly efficient dual-band metamaterial was realized by using a genetic algorithm to identify an array of H-shaped nanoresonators with an effective electric and magnetic response that maximizes absorption in each wavelength band when patterned on a flexible Kapton and Au thin film substrate stack. This conformal metamaterial absorber maintains its absorption properties when integrated onto curved surfaces of arbitrary materials, making it attractive for advanced coatings that suppress the infrared reflection from the protected surface.

  17. High Reliability Oscillators for Terahertz Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Terahertz sources based on lower frequency oscillators and amplifiers plus a chain of frequency multipliers are the workhorse technology for NASA's terahertz...

  18. THz leaky-wave antenna with high-directivity and beam-steering using CPW CRLH meta-material resonators

    Science.gov (United States)

    Si, Li-Ming; Sun, Hou-Jun; Lv, Xin

    2009-07-01

    A novel coplanar waveguide (CPW)-based composite right/left-handed (CRLH) structure for terahertz (THz) leaky wave antennas (LWAs) application with high directivity and beam steering capability is introduced. The structure of the CRLH-TL was composed of a slot and embedded resonators termed metamaterial resonators using planar CPW technology. There were three steps involved to design the structure of metamaterial resonator and position distribution of metamaterial resonators in the composite right/left-handed (CRLH) transmission lines. First, equivalent circuit model method (also called "transmission line model method") was used to create an equivalent circuit model of the element of metamaterial resonator. Second, from the equivalent circuit model, it was possible to correspond to two basic equivalent circuit parameters "series impedance and shunt admittance" from artificial transmission line structure "CPW-based metamaterial resonator". Finally, the dimensions of metamaterial resonator were calculated and optimized according to the dispersion diagram. Meanwhile, ohmic loss needs to be considered because it is high at THz wave and above frequency region. The LWAs with CPW-based CRLH could implement high-directivity and backward-to-forward beam steering which differs from the conventional one. A balanced CPW CRLH LWA is designed at the transition frequency of 1485 GHz and performances of high-directivity and wide-angle continuous beam-steering are demonstrated.

  19. Transformation optics and metamaterials.

    Science.gov (United States)

    Chen, Huanyang; Chan, C T; Sheng, Ping

    2010-05-01

    Underpinned by the advent of metamaterials, transformation optics offers great versatility for controlling electromagnetic waves to create materials with specially designed properties. Here we review the potential of transformation optics to create functionalities in which the optical properties can be designed almost at will. This approach can be used to engineer various optical illusion effects, such as the invisibility cloak.

  20. Mechanical meta-materials

    NARCIS (Netherlands)

    Zadpoor, A.A.

    2016-01-01

    The emerging concept of mechanical meta-materials has received increasing attention during the last few years partially due to the advances in additive manufacturing techniques that have enabled fabricating materials with arbitrarily complex micro/nano-architectures. The rationally designed

  1. Fractal THz metamaterials

    DEFF Research Database (Denmark)

    Malureanu, Radu; Jepsen, Peter Uhd; Xiao, S.

    2010-01-01

    The concept of metamaterials (MTMs) is acknowledged for providing new horizons for controlling electromagnetic radiations thus their use in frequency ranges otherwise difficult to manage (e.g. THz radiation) broadens our possibility to better understand our world as well as opens the path for new...

  2. Terahertz generation from graphite

    NARCIS (Netherlands)

    Ramakrishnan, G.; Chakkittakandy, R.; Planken, P.C.M.

    2009-01-01

    Generation of subpicosecond terahertz pulses is observed when graphite surfaces are illuminated with femtosecond near-infrared laser pulses. The nonlinear optical generation of THz pulses from graphite is unexpected since, in principle, the material possesses a centre of inversion symmetry.

  3. Terahertz Radome Inspection

    Directory of Open Access Journals (Sweden)

    Fabian Friederich

    2018-01-01

    Full Text Available Radomes protecting sensitive radar, navigational, and communications equipment of, e.g., aircraft, are strongly exposed to the environment and have to withstand harsh weather conditions and potential impacts. Besides their significance to the structural integrity of the radomes, it is often crucial to optimize the composite structures for best possible radio performance. Hence, there exists a significant interest in non-destructive testing techniques, which can be used for defect inspection of radomes in field use as well as for quality inspection during the manufacturing process. Contactless millimeter-wave and terahertz imaging techniques provide millimeter resolution and have the potential to address both application scenarios. We report on our development of a three-dimensional (3D terahertz imaging system for radome inspection during industrial manufacturing processes. The system was designed for operation within a machining center for radome manufacturing. It simultaneously gathers terahertz depth information in adjacent frequency ranges, from 70 to 110 GHz and from 110 to 170 GHz by combining two frequency modulated continuous-wave terahertz sensing units into a single measurement device. Results from spiraliform image acquisition of a radome test sample demonstrate the successful integration of the measurement system.

  4. Aperiodic-metamaterial-based absorber

    Directory of Open Access Journals (Sweden)

    Quanlong Yang

    2017-09-01

    Full Text Available The periodic-metamaterial-based perfect absorber has been studied broadly. Conversely, if the unit cell in the metamaterial-based absorber is arranged aperiodically (aperiodic-metamaterial-based absorber, how does it perform? Inspired by this, here we present a systematic study of the aperiodic-metamaterial-based absorber. By investigating the response of metamaterial absorbers based on periodic, Fibonacci, Thue-Morse, and quasicrystal lattices, we found that aperiodic-metamaterial-based absorbers could display similar absorption behaviors as the periodic one in one hand. However, their absorption behaviors show different tendency depending on the thicknesses of the spacer. Further studies on the angle and polarization dependence of the absorption behavior are also presented.

  5. Aperiodic-metamaterial-based absorber

    Science.gov (United States)

    Yang, Quanlong; Chen, Xieyu; Li, Yanfeng; Zhang, Xueqian; Xu, Yuehong; Tian, Zhen; Ouyang, Chunmei; Gu, Jianqiang; Han, Jiaguang; Zhang, Weili

    2017-09-01

    The periodic-metamaterial-based perfect absorber has been studied broadly. Conversely, if the unit cell in the metamaterial-based absorber is arranged aperiodically (aperiodic-metamaterial-based absorber), how does it perform? Inspired by this, here we present a systematic study of the aperiodic-metamaterial-based absorber. By investigating the response of metamaterial absorbers based on periodic, Fibonacci, Thue-Morse, and quasicrystal lattices, we found that aperiodic-metamaterial-based absorbers could display similar absorption behaviors as the periodic one in one hand. However, their absorption behaviors show different tendency depending on the thicknesses of the spacer. Further studies on the angle and polarization dependence of the absorption behavior are also presented.

  6. Existence conditions for bulk large-wavevector waves in metal-dielectric and graphene-dielectric multilayer hyperbolic metamaterials

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Andryieuski, Andrei; Lavrinenko, Andrei

    2014-01-01

    -dielectric and recently introduced graphene-dielectric stacks. We confirm that short-range surface plasmons in thin metal layers can give rise to hyperbolic metamaterial properties and demonstrate that long-range surface plasmons cannot. We also show that graphene-dielectric multilayers tend to support high-k waves...... and explore the range of parameters, where this is possible, confirming the prospects of using graphene for materials with hyperbolic dispersion. The suggested formalism is applicable to a large variety of structures, such as continuous or structured microwave, terahertz (THz) and optical metamaterials......We theoretically investigate general existence conditions for broadband bulk large-wavevector (high-k) propagating waves (such as volume plasmon polaritons in hyperbolic metamaterials) in arbitrary subwavelength periodic multilayers structures. Treating the elementary excitation in the unit cell...

  7. Manipulating scattering features by metamaterials

    Directory of Open Access Journals (Sweden)

    Lu Cui

    2016-01-01

    Full Text Available We present a review on manipulations of electromagnetic scattering features by using metamaterials or metasurfaces. Several approaches in controlling the scattered fields of objects are presented, including invisibility cloaks and radar illusions based on transformation optics, carpet cloak using gradient metamaterials, dc cloaks, mantle cloaks based on scattering cancellation, “skin” cloaks using phase compensation, scattering controls with coding/programmable metasurfaces, and scattering reductions by multilayered structures. Finally, the future development of metamaterials on scattering manipulation is predicted.

  8. Controlling light with photonic metamaterials

    OpenAIRE

    Zhang, Jianfa

    2013-01-01

    This thesis reports on my research efforts towards controlling light with photonic metamaterials for desired functionalities:I have demonstrated a new family of continuously metallic metamaterials-‘intaglio’ and ‘bas-relief’ metamaterials. They are formed of indented or raised sub-wavelength patterns with depth/height of the order 100 nm and offer a robust and flexible paradigm for engineering the spectral response of metals in the vis-NIR domains. Controlling the colour of metals by intaglio...

  9. Homogenization of resonant chiral metamaterials

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Menzel, C.; Rockstuhl, Carsten

    2010-01-01

    Homogenization of metamaterials is a crucial issue as it allows to describe their optical response in terms of effective wave parameters as, e.g., propagation constants. In this paper we consider the possible homogenization of chiral metamaterials. We show that for meta-atoms of a certain size...... an analytical criterion for performing the homogenization and a tool to predict the homogenization limit. We show that strong coupling between meta-atoms of chiral metamaterials may prevent their homogenization at all....

  10. Research Advance in Smart Metamaterials

    OpenAIRE

    Yu, Xiang-Long; Zhou, Ji

    2016-01-01

    Metamaterials, man-made materials, enable us to design our own "atoms", and thereby to create materials with unprecedented effective properties that have not yet been found in nature. Smart metamaterial is one of those that is an intelligent perceptive to the changes from external environments and simultaneously having the capability to respond to thermal and mechanical stimuli. This paper can provide a review on these smart metamaterials in perspective of science, engineering and industrial ...

  11. Graphene in a photonic metamaterial.

    Science.gov (United States)

    Papasimakis, Nikitas; Luo, Zhiqiang; Shen, Ze Xiang; De Angelis, Francesco; Di Fabrizio, Enzo; Nikolaenko, Andrey E; Zheludev, Nikolay I

    2010-04-12

    We demonstrate a photonic metamaterial that shows extraordinary sensitivity to the presence of a single atomic layer of graphene on its surface. Metamaterial's optical transmission increases multi-fold at the resonance frequency linked to the Fano-type plasmonic mode supported by the periodic metallic nanostructure. The experiments were performed with chemical vapor deposited (CVD) graphene covering a number of size-scaled metamaterial samples with plasmonic modes at different frequencies ranging from 167 to 187 Thz.

  12. Doped Chiral Polymer Metamaterials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Doped Chiral Polymer Metamaterials (DCPM) with tunable resonance frequencies have been developed by adding plasmonic inclusions into chiral polymers with variable...

  13. Cochlear bionic acoustic metamaterials

    Science.gov (United States)

    Ma, Fuyin; Wu, Jiu Hui; Huang, Meng; Fu, Gang; Bai, Changan

    2014-11-01

    A design of bionic acoustic metamaterial and acoustic functional devices was proposed by employing the mammalian cochlear as a prototype. First, combined with the experimental data in previous literatures, it is pointed out that the cochlear hair cells and stereocilia cluster are a kind of natural biological acoustic metamaterials with the negative stiffness characteristics. Then, to design the acoustic functional devices conveniently in engineering application, a simplified parametric helical structure was proposed to replace actual irregular cochlea for bionic design, and based on the computational results of such a bionic parametric helical structure, it is suggested that the overall cochlear is a local resonant system with the negative dynamic effective mass characteristics. There are many potential applications in the bandboard energy recovery device, cochlear implant, and acoustic black hole.

  14. Transformable topological mechanical metamaterials

    Science.gov (United States)

    Rocklin, D. Zeb; Zhou, Shangnan; Sun, Kai; Mao, Xiaoming

    2017-01-01

    Mechanical metamaterials are engineered materials whose structures give them novel mechanical properties, including negative Poisson's ratios, negative compressibilities and phononic bandgaps. Of particular interest are systems near the point of mechanical instability, which recently have been shown to distribute force and motion in robust ways determined by a nontrivial topological state. Here we discuss the classification of and propose a design principle for mechanical metamaterials that can be easily and reversibly transformed between states with dramatically different mechanical and acoustic properties via a soft strain. Remarkably, despite the low energetic cost of this transition, quantities such as the edge stiffness and speed of sound can change by orders of magnitude. We show that the existence and form of a soft deformation directly determines floppy edge modes and phonon dispersion. Finally, we generalize the soft strain to generate domain structures that allow further tuning of the material.

  15. Active photonic metamaterials

    OpenAIRE

    Sámson, Z.L; Gholipour, B; De Angelis, F.; Li, S.; Knight, K. J.; Zhang, J.; Uchino, T.; Huang, C. C.; MacDonald, K. F.; Ashburn, P.; Di Fabrizio, E.; Hewak, D W; Zheludev, N. I.

    2010-01-01

    Nanostructured photonic metamaterials with narrow-band responses provide a promising platform for applications ranging from slow-light and polarization control to optical modulation and the 'lasing spaser'. We show that the introduction of functional (nonlinear, switchable, gain, etc.) media into such structures provides a powerful paradigm for the active control of their resonant properties, for the enhancement of nonlinear responses and for strong switching performance in sub-wavelength dev...

  16. Infrared Semiconductor Metamaterials

    Science.gov (United States)

    2016-09-01

    AFRL-AFOSR-VA-TR-2016-0310 Infrared Semiconductor Metamaterials Jon Schuller UNIVERSITY OF CALIFORNIA SANTA BARBARA 3227 CHEADLE HL SANTA BARBARA, CA...S) AND ADDRESS(ES) University of California , Santa Barbara Office of Research, 3227 Cheadle Hall Santa Barbara, CA 93106-2050 8. PERFORMING...Using Heterojunction Resonators. Advanced Optical Materials, available online (2016). New discoveries, inventions, or patent disclosures: Do you have

  17. Microwave metamaterial absorber based on multiple square ring structures

    Directory of Open Access Journals (Sweden)

    Weicheng Zhou

    2015-11-01

    Full Text Available In this paper, we report the design, analysis, and simulation of quintuple-band metamaterial absorber (MMA in the microwave region. The absorber is constructed of a delicate periodic patterned structures and a metallic background plane, separated by a dielectric substrate. By manipulating the periodic patterned structures, high absorption can be obtained at five specific resonance frequencies. Moreover, the significantly high absorptions of quintuple-peaks are persistent with polarization independence, and the influence of angle of incidence for both TE and TM modes was also elucidated. For explaining the absorption mechanism of proposed structures, the electric and magnetic field distributions and resistance matching principal were given. Importantly, the design idea has the ability to be extended to other frequencies, like terahertz, infrared and optical frequencies.

  18. Microwave metamaterial absorber based on multiple square ring structures

    Science.gov (United States)

    Zhou, Weicheng; Wang, Pinghe; Wang, Nan; Jiang, Wei; Dong, Xiaochun; Hu, Song

    2015-11-01

    In this paper, we report the design, analysis, and simulation of quintuple-band metamaterial absorber (MMA) in the microwave region. The absorber is constructed of a delicate periodic patterned structures and a metallic background plane, separated by a dielectric substrate. By manipulating the periodic patterned structures, high absorption can be obtained at five specific resonance frequencies. Moreover, the significantly high absorptions of quintuple-peaks are persistent with polarization independence, and the influence of angle of incidence for both TE and TM modes was also elucidated. For explaining the absorption mechanism of proposed structures, the electric and magnetic field distributions and resistance matching principal were given. Importantly, the design idea has the ability to be extended to other frequencies, like terahertz, infrared and optical frequencies.

  19. Rich hybridized-polarization surface phonon polaritons in hyperbolic metamaterials

    Directory of Open Access Journals (Sweden)

    Q. Zhang

    2017-10-01

    Full Text Available We investigated hybridized-polarization surface phonon polaritons (HSPhPs of transversely truncated a metamaterial (MM that consists of alternating ionic-crystal and ordinary-dielectric layers. We predicted five HSPhPs in the reststrahlen frequency window of ionic-crystal layers, which belong to five different types, respectively. One is of Dyakonov-like type and another is traditional-like. The other three HSPhPs are of new type. We used a numerical-simulating method of attenuated total reflection (ATR measurements to examine them. The obtained ATR spectra also demonstrate that they are observable and exhibit their polarization features. These results expand the potential-application space of phononics and photonics in the infrared to the terahertz range.

  20. Rich hybridized-polarization surface phonon polaritons in hyperbolic metamaterials

    Science.gov (United States)

    Zhang, Q.; Zhou, S.; Fu, S. F.; Wang, X. Z.

    2017-10-01

    We investigated hybridized-polarization surface phonon polaritons (HSPhPs) of transversely truncated a metamaterial (MM) that consists of alternating ionic-crystal and ordinary-dielectric layers. We predicted five HSPhPs in the reststrahlen frequency window of ionic-crystal layers, which belong to five different types, respectively. One is of Dyakonov-like type and another is traditional-like. The other three HSPhPs are of new type. We used a numerical-simulating method of attenuated total reflection (ATR) measurements to examine them. The obtained ATR spectra also demonstrate that they are observable and exhibit their polarization features. These results expand the potential-application space of phononics and photonics in the infrared to the terahertz range.

  1. Light propagation in multilayer metamaterials

    NARCIS (Netherlands)

    Maas, R.C.

    2015-01-01

    Metamaterials are artificially constructed materials composed of sub-wavelength building blocks that are designed to interact with light in ways that cannot be achieved with natural materials. Over the last years, improvements in nanoscale fabrication and in metamaterial design have led to the

  2. Circuit modeling of graphene absorber in terahertz band

    Science.gov (United States)

    Taghvaee, Hamid Reza; Nasari, Hadiseh; Abrishamian, Mohammad Sadegh

    2017-01-01

    Here we develop and extend a transmission line method (TLM) to analyze the performance of graphene assisted metamaterial (GM) devices working in the terahertz (THz) band. We demonstrate that a circuit model can be presented for different parts of the device including graphene and also the patterned metallic sheet by analyzing the distribution of surface induced current. In pursuit of evaluating the efficiency and accuracy of our proposed method, we compare its results, obtained from an easy to implement MATLAB code for a typical GM absorber with those obtained from full wave simulations. The excellence of the proposed method in terms of computation time (showing more than 3 orders of magnitude reduction in run time) and memory resource besides producing results with acceptable agreement with the results of full wave simulation (with an error less than 5%) versus incident angle, dielectric thickness and chemical potential, nominates it as a promising approach to simulate other graphene-based devices.

  3. Radar illusion via metamaterials

    Science.gov (United States)

    Jiang, Wei Xiang; Cui, Tie Jun

    2011-02-01

    An optical illusion is an image of a real target perceived by the eye that is deceptive or misleading due to a physiological illusion or a specific visual trick. The recently developed metamaterials provide efficient approaches to generate a perfect optical illusion. However, all existing research on metamaterial illusions has been limited to theory and numerical simulations. Here, we propose the concept of a radar illusion, which can make the electromagnetic (EM) image of a target gathered by radar look like a different target, and we realize a radar illusion device experimentally to change the radar image of a metallic target into a dielectric target with predesigned size and material parameters. It is well known that the radar signatures of metallic and dielectric objects are significantly different. However, when a metallic target is enclosed by the proposed illusion device, its EM scattering characteristics will be identical to that of a predesigned dielectric object under the illumination of radar waves. Such an illusion device will confuse the radar, and hence the real EM properties of the metallic target cannot be perceived. We designed and fabricated the radar illusion device using artificial metamaterials in the microwave frequency, and good illusion performances are observed in the experimental results.

  4. Metamaterial saturable absorber mirror.

    Science.gov (United States)

    Dayal, Govind; Ramakrishna, S Anantha

    2013-02-01

    We propose a metamaterial saturable absorber mirror at midinfrared wavelengths that can show a saturation of absorption with intensity of incident light and switch to a reflecting state. The design consists of an array of circular metallic disks separated by a thin film of vanadium dioxide (VO(2)) from a continuous metallic film. The heating due to the absorption in the absorptive state causes the VO(2) to transit to a metallic phase from the low temperature insulating phase. The metamaterial switches from an absorptive state (R≃0.1%) to a reflective state (R>95%) for a specific threshold intensity of the incident radiation corresponding to the phase transition of VO(2), resulting in the saturation of absorption in the metamaterial. The computer simulations show over 99.9% peak absorbance, a resonant bandwidth of about 0.8 μm at 10.22 μm wavelengths, and saturation intensity of 140 mW cm(-2) for undoped VO(2) at room temperature. We also carried out numerical simulations to investigate the effects of localized heating and temperature distribution by solving the heat diffusion problem.

  5. Tunability of Superconducting Metamaterials

    Science.gov (United States)

    Ricci, Michael C.; Xu, Hua; Prozorov, Ruslan; Zhuravel, Alexander P.; Ustinov, Alexey V.; Anlage, Steven M.

    2007-06-01

    Metamaterials are artificial structures with unique electromagnetic properties, such as relative dielectric permittivity and magnetic permeability with values less than 1, or even negative. Because these properties are so sensitive to loss, we have developed metamaterials comprised of superconducting waveguides, wires, and split-ring resonators. An important requirement for applications of these metamaterials is the ability to tune the frequency at which the unique electromagnetic response occurs. In this paper we present three methods (unique to superconductors) to accomplish this tuning: temperature, dc magnetic field, and rf magnetic field. Data are shown for dc and rf magnetic field tuning of a single Nb split-ring resonator (SRR). It was found that the dc field tuning was hysteritic in the resonant frequency data, while the quality factor, $Q$, was less hystertic. The rf power tuning showed no hysteresis, but did show supression of the $Q$ at high power. Magneto-optical images reveal inhomogeneous magnetic vortex entry in the dc field tuning, and laser scanning photoresponse images for a YBa$_2$Cu$_3$O$_{7-\\delta}$ SRR reveals the current distribution in the rings.

  6. Ultrasonic metamaterials with negative modulus.

    Science.gov (United States)

    Fang, Nicholas; Xi, Dongjuan; Xu, Jianyi; Ambati, Muralidhar; Srituravanich, Werayut; Sun, Cheng; Zhang, Xiang

    2006-06-01

    The emergence of artificially designed subwavelength electromagnetic materials, denoted metamaterials, has significantly broadened the range of material responses found in nature. However, the acoustic analogue to electromagnetic metamaterials has, so far, not been investigated. We report a new class of ultrasonic metamaterials consisting of an array of subwavelength Helmholtz resonators with designed acoustic inductance and capacitance. These materials have an effective dynamic modulus with negative values near the resonance frequency. As a result, these ultrasonic metamaterials can convey acoustic waves with a group velocity antiparallel to phase velocity, as observed experimentally. On the basis of homogenized-media theory, we calculated the dispersion and transmission, which agrees well with experiments near 30 kHz. As the negative dynamic modulus leads to a richness of surface states with very large wavevectors, this new class of acoustic metamaterials may offer interesting applications, such as acoustic negative refraction and superlensing below the diffraction limit.

  7. Controlling sound with acoustic metamaterials

    DEFF Research Database (Denmark)

    Cummer, Steven A. ; Christensen, Johan; Alù, Andrea

    2016-01-01

    -scale metamaterial structures and converting laboratory experiments into useful devices. In this Review, we outline the designs and properties of materials with unusual acoustic parameters (for example, negative refractive index), discuss examples of extreme manipulation of sound and, finally, provide an overview......Acoustic metamaterials can manipulate and control sound waves in ways that are not possible in conventional materials. Metamaterials with zero, or even negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales....... The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. Active acoustic metamaterials use external control to create...

  8. Electrical access to critical coupling of circularly polarized waves in graphene chiral metamaterials.

    Science.gov (United States)

    Kim, Teun-Teun; Oh, Sang Soon; Kim, Hyeon-Don; Park, Hyun Sung; Hess, Ortwin; Min, Bumki; Zhang, Shuang

    2017-09-01

    Active control of polarization states of electromagnetic waves is highly desirable because of its diverse applications in information processing, telecommunications, and spectroscopy. However, despite the recent advances using artificial materials, most active polarization control schemes require optical stimuli necessitating complex optical setups. We experimentally demonstrate an alternative-direct electrical tuning of the polarization state of terahertz waves. Combining a chiral metamaterial with a gated single-layer sheet of graphene, we show that transmission of a terahertz wave with one circular polarization can be electrically controlled without affecting that of the other circular polarization, leading to large-intensity modulation depths (>99%) with a low gate voltage. This effective control of polarization is made possible by the full accessibility of three coupling regimes, that is, underdamped, critically damped, and overdamped regimes by electrical control of the graphene properties.

  9. A dynamically reconfigurable Fano metamaterial through graphene tuning for switching and sensing applications

    KAUST Repository

    Amin, M.

    2013-07-01

    We report on a novel electrically tunable hybrid graphene-gold Fano resonator. The proposed metamaterial consists of a square graphene patch and a square gold frame. The destructive interference between the narrow- and broadband dipolar surface plasmons, which are induced respectively on the surfaces of the graphene patch and the gold frame, leads to the plasmonic equivalent of electromagnetically induced transparency (EIT). The response of the metamaterial is polarization independent due to the symmetry of the structure and its spectral features are shown to be highly controllable by changing a gate voltage applied to the graphene patch. Additionally, effective group index of the device is retrieved and is found to be very high within the EIT window suggesting its potential use in slow light applications. Potential outcomes such as high sensing ability and switching at terahertz frequencies are demonstrated through numerical simulations with realistic parameters.

  10. A metamaterial-coupled hot-electron-bolometer working at THz frequencies

    Science.gov (United States)

    Cibella, S.; Carelli, P.; Castellano, M. G.; Chiarello, F.; Gaggero, A.; Giovine, E.; Scalari, G.; Torrioli, G.; Leoni, R.

    2017-02-01

    We will report our recent results using ultrathin NbN films (4-5 nm) for developing both conventional antenna-coupled hot-electron-bolometers (AC-HEBs) and of a novel type of phonon cooled HEB electrically-coupled to a metamaterial acting as a resonant absorber at THz frequencies (MM-HEB), optically-coupled through arrays of split ring resonators (metadevices). In a phonon-cooled HEB, being the active layer an ultrathin film of superconducting NbN, we have an ultrafast thermal direct detector that is also frequency selective thanks to the integration with the resonant metamaterial. We characterized both the AC-HEB and the MM-HEB by electro optical measurements using as a sources both the black body emission and terahertz quantum cascade lasers (THz-QCLs) and we compared their performances.

  11. A polarization insensitive and broadband metamaterial absorber based on three-dimensional structure

    Science.gov (United States)

    Tang, Jingyao; Xiao, Zhongyin; Xu, Kaikai; Liu, Dejun

    2016-08-01

    In this paper, we propose a three-dimensional metamaterial absorber based on tailored resistive film patch array. The numerical results show that a broadband abs orption more than 90% can be achieved from 58.6 to 91.4 GHz for either transverse electric or magnetic polarization wave at normal incidence. And the E-field, surface current and power loss density distributions in the absorber are investigated to explain the physical mechanism of high absorption. In addition, the absorption efficiency of oblique incidence is also elucidated. According to the analysis of the E-field and power loss density distributions, we explain the absorption differences between TE and TM mode at oblique incidence. The proposed metamaterial absorber will pave the way for practical applications, such as sensing, imaging and stealth technology. Importantly, the design idea has the ability to be extended to terahertz, infrared and optical region.

  12. A dynamically reconfigurable Fano metamaterial through graphene tuning for switching and sensing applications.

    Science.gov (United States)

    Amin, M; Farhat, M; Baǧcı, H

    2013-01-01

    We report on a novel electrically tunable hybrid graphene-gold Fano resonator. The proposed metamaterial consists of a square graphene patch and a square gold frame. The destructive interference between the narrow- and broadband dipolar surface plasmons, which are induced respectively on the surfaces of the graphene patch and the gold frame, leads to the plasmonic equivalent of electromagnetically induced transparency (EIT). The response of the metamaterial is polarization independent due to the symmetry of the structure and its spectral features are shown to be highly controllable by changing a gate voltage applied to the graphene patch. Additionally, effective group index of the device is retrieved and is found to be very high within the EIT window suggesting its potential use in slow light applications. Potential outcomes such as high sensing ability and switching at terahertz frequencies are demonstrated through numerical simulations with realistic parameters.

  13. Pancharatnam-Berry phase induced spin-selective transmission in herringbone dielectric metamaterials

    CERN Document Server

    Kenney, Mitchell; Zhang, Xueqian; Su, Xiaoqiang; Kim, Teun-Teun; Wang, Dongyang; Wu, Dongmin; Ouyang, Chunmei; Han, Jiaguang; Zhang, Weili; Sun, Hongbo; Zhang, Shuang

    2016-01-01

    Manipulating the polarisation of light is crucial for sensing and imaging applications. One such aspect in particular is selective transmission of one circular polarisation (spin) when light is transmitted through a medium or a device. However, most present methods of achieving this have relatively low efficiency and selectivity, whilst high selectivity examples rely on lossy and complex three-dimensional helical or multilayer structures. Here, we propose a dielectric metamaterial approach for achieving spin-selective transmission of electromagnetic waves, utilizing spin-controlled constructive or destructive interference between two Pancharatnam-Berry (PB) phases in conjunction with propagative dynamic phase. The dielectric metamaterial, consisting of monolithic silicon herringbone structures, exhibits a broadband operation in the terahertz regime whilst obtaining a spin-selective efficiency upwards of 60%. Such a device is robust and is not easily degraded by errors in fabrication.

  14. Highly sensitive and selective sugar detection by terahertz nano-antennas

    CERN Document Server

    Lee, Dong-Kyu; Lee, Jun-Seok; Kim, Hyo-Seok; Kim, Chulki; Kim, Jae Hun; Lee, Taikjin; Son, Joo-Hiuk; Park, Q-Han; Seo, Minah

    2015-01-01

    Molecular recognition and discrimination of carbohydrates are important because carbohydrates perform essential roles in most living organisms for energy metabolism and cell-to-cell communication. Nevertheless, it is difficult to identify or distinguish various carbohydrate molecules owing to the lack of a significant distinction in the physical or chemical characteristics. Although there has been considerable effort to develop a sensing platform for individual carbohydrates selectively using chemical receptors or an ensemble array, their detection and discrimination limits have been as high in the millimolar concentration range. Here we show a highly sensitive and selective detection method for the discrimination of carbohydrate molecules using nano-slot-antenna array-based sensing chips which operate in the terahertz frequency range. This THz metamaterial sensing tool recognizes various types of carbohydrate molecules over a wide range of molecular concentrations. Strongly localized and enhanced terahertz t...

  15. A micromachined freestanding terahertz absorber with an array of metallic patches

    Directory of Open Access Journals (Sweden)

    Hamdi Torun

    2016-03-01

    Full Text Available An array of square metallic patches on a thin suspended dielectric layer is introduced as an effective terahertz absorber. The suspended structure is placed on a metalized substrate and the device exhibits metamaterial behavior at specific frequencies determined by the size of the patches. It is feasible to place patches with different sizes in an array formation for a broadband absorber. In array configuration, individual elements induce distinct resonances yielding narrow band absorption regions. Design of the absorber is described using electromagnetic simulations. The absorber structure was fabricated on a silicon wafer using standard microfabrication techniques. The characteristics of the absorber were measured using a terahertz time domain spectroscope. The measured data match well the simulations indicating strong absorption peaks in a band of 0.5-2 THz.

  16. Low-loss, infrared and terahertz nanophotonics using surface phonon polaritons

    Directory of Open Access Journals (Sweden)

    Caldwell Joshua D.

    2015-04-01

    Full Text Available The excitation of surface-phonon-polariton (SPhP modes in polar dielectric crystals and the associated new developments in the field of SPhPs are reviewed. The emphasis of this work is on providing an understanding of the general phenomenon, including the origin of the Reststrahlen band, the role that optical phonons in polar dielectric lattices play in supporting sub-diffraction-limited modes and how the relatively long optical phonon lifetimes can lead to the low optical losses observed within these materials. Based on this overview, the achievements attained to date and the potential technological advantages of these materials are discussed for localized modes in nanostructures, propagating modes on surfaces and in waveguides and novel metamaterial designs, with the goal of realizing low-loss nanophotonics and metamaterials in the mid-infrared to terahertz spectral ranges.

  17. Observation of electromagnetically induced transparency-like transmission in terahertz asymmetric waveguide-cavities systems.

    Science.gov (United States)

    Chen, Lin; Gao, Chunmei; Xu, Jiaming; Zang, Xiaofei; Cai, Bin; Zhu, Yiming

    2013-05-01

    Electromagnetically induced transparency (EIT)-like transmission was demonstrated in terahertz asymmetric parallel plate waveguides with two identical cavities. By shifting the position of the bottom cavity from the symmetric position in the propagation direction, both the phases of the propagating wave at resonances and the coupling strengths between two cavities are changed, resulting in exciting the additional asymmetric resonance and manipulating the detuning of two different resonant frequencies. The transparent peak between two resonances comes from the cancelation of symmetric and asymmetric resonances. We also use the physical picture of excitation of quasi-dark mode to explain this EIT-like transmission, which is similar to the metamaterial systems.

  18. Terahertz spectrum splitting by a graphene-covered array of rectangular grooves.

    Science.gov (United States)

    Tavakol, Mohammad Reza; Saba, Amirhossein; Jafargholi, Amir; Khavasi, Amin

    2017-12-01

    We propose a bidirectional terahertz (THz) spectrum splitter using a practically simple metamaterial structure consisting of rectangular grooves covered by graphene. Thanks to the graphene optoelectronic tunability and by adjusting the grooves width, this structure provides nearly 2π phase shift. At the same time, the reflection efficiency is acceptable throughout the phase shifts. We design each of the meta-atoms using a circuit model, and then we synthesize the final supercell based on the generalized Snell's law so that the structure reflects different frequency waves to totally different directions. The full-wave simulations demonstrate the beam splitting with a remarkable efficiency of around 80%.

  19. Three Dimensional Micro and Nano Fabrication of Metamaterials

    Science.gov (United States)

    Zhou, Fan

    The concept of artificially structured metamateials arises as a promising solution to offer broad tunability of material properties. Rather than on its chemical composition, macroscopic properties of metamateirals depend on the hierarchical assembly of the "artificial atoms" of the structure. Many novel designs have been reported to enable exotic properties of metamaterials. However, experimental realization of these designs is facing a great challenge due to stringent requirements on precise fabrication of subwavelength fine features in three dimensional (3D). In this dissertation, we aim to create powerful and reliable 3D fabrication approaches to bridge the gap between design and realization. Three dimensional fabrication of terahertz (THz) metamaterial and optical metamaterial by additive manufacturing approaches are demonstrated. For fabricating THz metamaterials, the design and testing of a scalable projection micro-stereo-lithography system that offers the 3D fabrication capability is presented. By taking advantage of transformation optics theory, a study in design, fabrication, and characterization of the THz invisibility cloak was performed. The cloak successfully concealed both the geometrical and spectroscopic signatures of an alpha-lactose monohydrate absorber, making it undetectable from 0.3 to 0.6 THz. Following this successful demonstration, we further created the broadband 3D flattened Luneburg lens for THz imaging. The lens is transformed from its original spherical shape and can focus THz plane waves from ultra-wide angles at the focal plane without geometrical aberrations, and vice versa. 2D imaging independent of polarizations is demonstrated. For optical metamaterial, we developed nanoimprint lithography and nanotransfer printing process to realize 3D nano-grating structure in an additive fashion. Based on this method, we successfully designed and created the upright U-shaped spit ring resonators (SRRs) showing artificial magnetism beyond the

  20. Numerical study of long Josephson junctions coupled to a high-Q cavity

    DEFF Research Database (Denmark)

    Grønbech-Jensen, N.; Pedersen, Niels Falsig; Davidson, A.

    1990-01-01

    Long Josephson junctions coupled to a high-Q resonator are studied numerically and compared with recently published approximative results, obtained by using a perturbative approach to the fluxon motion in the junction. The similarities and differences in the two approaches are discussed.......Long Josephson junctions coupled to a high-Q resonator are studied numerically and compared with recently published approximative results, obtained by using a perturbative approach to the fluxon motion in the junction. The similarities and differences in the two approaches are discussed....

  1. Applications of Hyperbolic Metamaterial Substrates

    Directory of Open Access Journals (Sweden)

    Yu Guo

    2012-01-01

    Full Text Available We review the properties of hyperbolic metamaterials and show that they are promising candidates as substrates for nanoimaging, nanosensing, fluorescence engineering, and controlling thermal emission. Hyperbolic metamaterials can support unique bulk modes, tunable surface plasmon polaritons, and surface hyperbolic states (Dyakonov plasmons that can be used for a variety of applications. We compare the effective medium predictions with practical realizations of hyperbolic metamaterials to show their potential for radiative decay engineering, bioimaging, subsurface sensing, metaplasmonics, and super-Planckian thermal emission.

  2. Mid-infrared tunable metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Brener, Igal; Miao, Xiaoyu; Shaner, Eric A.; Passmore, Brandon Scott

    2017-07-11

    A mid-infrared tunable metamaterial comprises an array of resonators on a semiconductor substrate having a large dependence of dielectric function on carrier concentration and a semiconductor plasma resonance that lies below the operating range, such as indium antimonide. Voltage biasing of the substrate generates a resonance shift in the metamaterial response that is tunable over a broad operating range. The mid-infrared tunable metamaterials have the potential to become the building blocks of chip based active optical devices in mid-infrared ranges, which can be used for many applications, such as thermal imaging, remote sensing, and environmental monitoring.

  3. Quantum metamaterial without local control

    Science.gov (United States)

    Shvetsov, A.; Satanin, A. M.; Nori, Franco; Savel'ev, S.; Zagoskin, A. M.

    2013-06-01

    A quantum metamaterial can be implemented as a quantum coherent one-dimensional array of qubits placed in a transmission line. The properties of quantum metamaterials are determined by the local quantum state of the system. Here we show that a spatially periodic quantum state of such a system can be realized without direct control of the constituent qubits, by their interaction with the initializing (“priming”) pulses sent through the system in opposite directions. The properties of the resulting quantum photonic crystal are determined by the choice of the priming pulses. This proposal can be readily generalized to other implementations of quantum metamaterials.

  4. Solid-state quantum metamaterials

    Science.gov (United States)

    Wilson, Richard; Everitt, Mark; Saveliev, Sergey; Zagoskin, Alexandre

    2013-03-01

    Quantum metamaterials provide a promising potential test bed for probing the quantum-classical transition. We propose a scalable and feasible architecture for a solid-state quantum metamaterial. This consists of an ensemble of superconducting flux qubits inductively coupled to a superconducting transmission line. We make use of fully quantum mechanical models which account for decoherence, input and readout to study the behaviour of prototypical 1D and 2D quantum metamaterials. In addition to demonstrating some of the novel phenomena that arise in these systems, such as ``quantum birefringence,'' we will also discuss potential applications.

  5. Mid-infrared tunable metamaterials

    Science.gov (United States)

    Brener, Igal; Miao, Xiaoyu; Shaner, Eric A; Passmore, Brandon Scott; Jun, Young Chul

    2015-04-28

    A mid-infrared tunable metamaterial comprises an array of resonators on a semiconductor substrate having a large dependence of dielectric function on carrier concentration and a semiconductor plasma resonance that lies below the operating range, such as indium antimonide. Voltage biasing of the substrate generates a resonance shift in the metamaterial response that is tunable over a broad operating range. The mid-infrared tunable metamaterials have the potential to become the building blocks of chip based active optical devices in mid-infrared ranges, which can be used for many applications, such as thermal imaging, remote sensing, and environmental monitoring.

  6. Metamaterial Perfect Absorber Analyzed by a Meta-cavity Model Consisting of Multilayer Metasurfaces.

    Science.gov (United States)

    Bhattarai, Khagendra; Silva, Sinhara; Song, Kun; Urbas, Augustine; Lee, Sang Jun; Ku, Zahyun; Zhou, Jiangfeng

    2017-09-05

    We demonstrate that the metamaterial perfect absorber behaves as a meta-cavity bounded between a resonant metasurface and a metallic thin-film reflector. The perfect absorption is achieved by the Fabry-Perot cavity resonance via multiple reflections between the "quasi-open" boundary of resonator and the "close" boundary of reflector. The characteristic features including angle independence, ultra-thin thickness and strong field localization can be well explained by this meta-cavity model. With this model, metamaterial perfect absorber can be redefined as a meta-cavity exhibiting high Q-factor, strong field enhancement and extremely high photonic density of states, thereby promising novel applications for high performance sensor, infrared photodetector and cavity quantum electrodynamics devices.

  7. Simulation and Analysis of a Metamaterial Sensor Based on a Microring Resonator

    Science.gov (United States)

    Huang, Ming; Yang, Jingjing; Jun, Sun; Mu, Shujuan; Lan, Yaozhong

    2011-01-01

    Metamaterials are artificial media structured on a size scale smaller than the wavelength of external stimuli, that may provide novel tools to significantly enhance the sensitivity and resolution of the sensors. In this paper, we derive the dispersion relation of hollow cylindrical dielectric waveguide, and compute the resonant frequencies and Q factors of the corresponding Whispering-Gallery-Modes (WGM). A metamaterial sensor based on microring resonator operating in WGM is proposed, and the resonance intensity spectrum curves in the frequency range from 185 to 212 THz were studied under different sensing conditions. Full-wave simulations, considering the frequency shift sensitivity influenced by the change of core media permittivity, the thickness and permittivity of the adsorbed substance, prove that the sensitivity of the metamaterial sensor is more than 7 times that of the traditional microring resonator sensor, and the metamaterial layer loaded in the inner side of the microring doesn’t affect the high Q performance of the microring resonator. PMID:22163933

  8. Terahertz (THZ) Imaging

    Science.gov (United States)

    2006-03-01

    Especially for thin films of material the absorption and time delay of a THz pulse are mostly too low to be detected. 48. Nemec, H.; Kuzel, P.; Khazan, M...the summary) states that the use of thin ZnTe electro-optic sensors for coherent characterization of a freely propagating terahertz beam...on a GaAs wafer is determined by the diameter of the gating- 40 beam-induced thin photo carrier layer. With a dynamic aperture created on a GaAs

  9. Thermal loss and soldering effect study of high-Q antennas in handheld devices

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Jagielski, Ole; Pedersen, Gert Frølund

    2013-01-01

    High-Q antennas are attractive because, besides being narrow-band, they have the advantage of being more compact and therefore occupy less volume in a mobile device. However, they can become very lossy especially at lower frequencies. In this paper it is investigated how low a thermal loss...

  10. Tunable High-Q N-Path Band-Pass Filters: Modeling and Verification

    NARCIS (Netherlands)

    Ghaffari, A.; Klumperink, Eric A.M.; Soer, M.C.M.; Nauta, Bram

    2011-01-01

    Abstract—A differential single-port switched-RC N-path filter with band-pass characteristic is proposed. The switching frequency defines the center frequency, while the RC-time and duty cycle of the clock define the bandwidth. This allows for high-Q highly tunable filters which can for instance be

  11. High-Q plasmonic infrared absorber for sensing of molecular resonances in hybrid lead halide perovskites

    Science.gov (United States)

    Dayal, Govind; Solanki, Ankur; Chin, Xin Yu; Sum, Tze Chien; Soci, Cesare; Singh, Ranjan

    2017-08-01

    Plasmonic resonances in sub-wavelength metal-dielectric-metal cavities have been shown to exhibit strong optical field enhancement. The large field enhancements that occur in sub-wavelength regions of the cavity can drastically boost the performance of microcavity based detectors, electromagnetic wave absorbers, metasurface hologram, and nonlinear response of the material in a cavity. The performance efficiencies of these plasmonic devices can be further improved by designing tunable narrow-band high-Q cavities. Here, we experimentally and numerically demonstrate high-Q resonances in metal-dielectric-metal cavity consisting of an array of conductively coupled annular and rectangular apertures separated from the bottom continuous metal film by a thin dielectric spacer. Both, the in-plane and out of plane coupling between the resonators and the continuous metal film have been shown to support fundamental and higher order plasmonic resonances which result in high-Q response at mid-infrared frequencies. As a sensor application of the high-Q cavity, we sense the vibrational resonances of an ultrathin layer of solution-processed organic-inorganic hybrid lead halide perovskites.

  12. Conical and bi-conical high-Q optical nanofiber microcoil resonator

    OpenAIRE

    Xu, Fei; Horak, Peter; Brambilla, Gilberto

    2006-01-01

    The Q-factor of the optical nanowire microcoil resonator is calculated and compared for different geometries. The results suggest that the Q-factor is very sensitive to the coupling conditions and high-Q resonators can be obtained more easily when the geometry of the nanowire microcoil resonator or its coupling contour has a bi-conical profile.

  13. Conical and biconical ultra-high-Q optical-fiber nanowire microcoil resonator.

    Science.gov (United States)

    Xu, Fei; Horak, Peter; Brambilla, Gilberto

    2007-02-01

    New 3D geometries of the optical nanowire microcoil resonator are suggested and investigated theoretically. The dependence of the Q factor on coupling parameters is calculated and compared for three different profiles. Results suggest that ultra-high-Q resonators can be fabricated more easily when the nanowire microcoil resonator has a biconical profile.

  14. Materials selection for low temperature processed high Q resonators using ashby approach

    NARCIS (Netherlands)

    Kazmi, S.N.R.; Salm, Cora; Schmitz, Jurriaan

    2009-01-01

    MicroElectroMechanical Systems (MEMS) is an emerging class of microfabrication technology that can truly be anticipated as an enabling technology for future radio frequency (RF) communications. This work focuses on the material selection using the Ashby approach for the high-Q resonators that need

  15. Photonic crystals and metamaterials

    Science.gov (United States)

    Lourtioz, Jean-Michel

    2008-01-01

    Recent results obtained on semiconductor-based photonic crystal devices are of great promise for future developments of photonic crystals and their applications to 'all-photonic' integrated circuits. Device performance mostly relies on the strong confinement of light thanks to photonic bandgap effects, but photonic crystals also exhibit remarkable dispersion properties in their transmission bands, thus opening the perspective of new optical functionalities. Slow light, supercollimation, superprism, and negative refraction effects are among the fascinating phenomena which strongly motivate the community. Studies in these directions parallel those on metamaterials, which are expected to provide a simultaneous control of the dielectric permittivity and of the magnetic permeability. In this article, we briefly review some important advances on photonic crystals and metamaterials, as these two topics received a particular attention during the "Nanosciences et Radioélectricité" workshop organized by CNFRS in Paris on the 20th and 21st of March 2007. To cite this article: J.-M. Lourtioz, C. R. Physique 9 (2008).

  16. Properties of dynamical electromagnetic metamaterials

    Science.gov (United States)

    Padilla, Willie J.; Averitt, Richard D.

    2017-08-01

    Electromagnetic metamaterials consist of two or three dimensional arrays of tailored metallic and/or dielectric inclusions and provide unprecedented sub-wavelength control over light-matter interactions. Metamaterials are fashioned to yield a specific response to the electric and magnetic components of light and may be treated as effective media, described by effective optical constants {μ }{{eff}} and {{ɛ }}{{eff}}, and have realized a multitude of exotic properties difficult to achieve with natural materials. An inductive-capacitive unit cell geometry provides enhanced values of optical constants, as well as the ability to dynamically control the novel responses exhibited by electromagnetic metamaterials. The ability of metamaterials to achieve real-time dynamic properties has realized novel applications and has made them relevant for the next revolution in advanced materials and related devices.

  17. Stimulated Brillouin scattering in metamaterials

    CERN Document Server

    Smith, M J A; de Sterke, C Martijn; Wolff, C; Lapine, M; Poulton, C G

    2016-01-01

    We compute the SBS gain for a metamaterial comprising a cubic lattice of dielectric spheres suspended in a background dielectric material. Theoretical methods are presented to calculate the optical, acoustic, and opto-acoustic parameters that describe the SBS properties of the material at long wavelengths. Using the electromagnetic and strain energy densities we accurately characterise the optical and acoustic properties of the metamaterial. From a combination of energy density methods and perturbation theory, we recover the appropriate terms of the photoelastic tensor for the metamaterial. We demonstrate that electrostriction is not necessarily the dominant mechanism in the enhancement and suppression of the SBS gain coefficient in a metamaterial, and that other parameters, such as the Brillouin linewidth, can dominate instead. Examples are presented that exhibit an order of magnitude enhancement in the SBS gain as well as perfect suppression.

  18. Optical Metamaterials Fundamentals and Applications

    CERN Document Server

    Cai, Wenshan

    2010-01-01

    Metamaterials—artificially structured materials with engineered electromagnetic properties—have enabled unprecedented flexibility in manipulating electromagnetic waves and producing new functionalities. In just a few years, the field of optical metamaterials has emerged as one of the most exciting topics in the science of light, with stunning and unexpected outcomes that have fascinated scientists and the general public alike. This volume details recent advances in the study of optical metamaterials, ranging from fundamental aspects to up-to-date implementations, in one unified treatment. Important recent developments and applications such as superlenses and cloaking devices are also treated in detail and made understandable. Optical Metamaterials will serve as a very timely book for both newcomers and advanced researchers in this rapidly evolving field. Early praise for Optical Metamaterials: "...this book is timely bringing to students and other new entrants to the field the most up to date concepts. Th...

  19. Advanced fabrication of hyperbolic metamaterials

    DEFF Research Database (Denmark)

    Shkondin, Evgeniy; Sukham, Johneph; Panah, Mohammad Esmail Aryaee

    2017-01-01

    Hyperbolic metamaterials can provide unprecedented properties in accommodation of high-k (high wave vector) waves and enhancement of the optical density of states. To reach such performance the metamaterials have to be fabricated with as small imperfections as possible. Here we report on our...... advances in two approaches in fabrication of optical metamaterials. We deposit ultrathin ultrasmooth gold layers with the assistance of organic material (APTMS) adhesion layer. The technology supports the stacking of such layers in a multiperiod construction with alumina spacers between gold films, which...... is expected to exhibit hyperbolic properties in the visible range. As the second approach we apply the atomic layer deposition technique to arrange vertical alignment of layers or pillars of heavily doped ZnO or TiN, which enables us to produce hyperbolic metamaterials for the near- and mid-infrared ranges....

  20. Hyperbolic Metamaterials with Complex Geometry

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Andryieuski, Andrei; Zhukovsky, Sergei

    2016-01-01

    We investigate new geometries of hyperbolic metamaterialssuch as highly corrugated structures, nanoparticle monolayer assemblies, super-structured or vertically arranged multilayersand nanopillars. All structures retain basic propertiesof hyperbolic metamaterials, but have functionality improved...

  1. Terahertz imaging for styrofoam inspection

    Science.gov (United States)

    Pradarutti, B.; Riehemann, S.; Notni, G.; Tünnermann, A.

    2007-09-01

    Imaging of styrofoam with the help of ultrashort Terahertz pulses is investigated. With a combination of pulse amplitude and time delay imaging it is possible to speed up the measurement about two orders of magnitudes.

  2. From surface to volume plasmons in hyperbolic metamaterials: General existence conditions for bulk high-k waves in metal-dielectric and graphene-dielectric multilayers

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Andryieuski, Andrei; Sipe, John E.

    2014-01-01

    -dielectric and recently introduced graphene-dielectric stacks. We confirm that short-range surface plasmons in thin metal layers can give rise to hyperbolic metamaterial properties and demonstrate that long-range surface plasmons cannot. We also show that graphene-dielectric multilayers tend to support high- k waves...... and explore the range of parameteres for which this is possible, confirming the prospects of using graphene for materials with hyperbolic dispersion. The approach is applicable to a large variety of structures, such as continuous or structured microwave, terahertz, and optical metamaterials.......We theoretically investigate general existence conditions for broadband bulk large-wave-vector (high- k ) propagating waves (such as volume plasmon polaritons in hyperbolic metamaterials) in subwavelength periodic multilayer structures. Describing the elementary excitation in the unit cell...

  3. Implementation of a Quantum Metamaterial

    OpenAIRE

    Macha, Pascal; Oelsner, Gregor; Reiner, Jan-Michael; Marthaler, Michael; André, Stephan; Schön, Gerd; Huebner, Uwe; Meyer, Hans-Georg; Il'ichev, Evgeni; Ustinov, Alexey V.

    2013-01-01

    Manipulating the propagation of electromagnetic waves through sub-wavelength sized artificial structures is the core function of metamaterials. Resonant structures, such as split ring resonators, play the role of artificial "atoms" and shape the magnetic response. Superconducting metamaterials moved into the spotlight for their very low ohmic losses and the possibility to tune their resonance frequency by exploiting the Josephson inductance. Moreover, the nonlinear nature of the Josephson ind...

  4. Quantum metamaterial without local control

    OpenAIRE

    Shvetsov, A.; Satanin, A. M.; Nori, Franco; Savel'ev, S.; Zagoskin, A. M.

    2013-01-01

    A quantum metamaterial can be implemented as a quantum coherent 1D array of qubits placed in a transmission line. The properties of quantum metamaterials are determined by the local quantum state of the system. Here we show that a spatially-periodic quantum state of such a system can be realized without direct control of the constituent qubits, by their interaction with the initializing ("priming") pulses sent through the system in opposite directions. The properties of the resulting quantum ...

  5. Terahertz Imaging of Subjects With Concealed Weapons

    National Research Council Canada - National Science Library

    Dickinson, Jason C; Goyette, Thoms M; Gatesman, Andrew J; Joseph, Cecil S; Root, Zachary G; Giles, Robert H; Waldman, Jerry; Nixon, William E

    2006-01-01

    .... Two contrasting techniques were used to collect the imagery. Both methods made use of in-house transceivers, consisting of two ultra-stable far-infrared lasers, terahertz heterodyne detection systems, and terahertz anechoic chambers...

  6. Resonant metallic nanostructures for enhanced terahertz spectroscopy

    KAUST Repository

    Toma, A.

    2015-11-12

    We present our recent studies on terahertz resonant dipole nanoantennas. Exploiting the localization and enhancement capabilities of these devices, we introduce an effective method to perform terahertz spectroscopy on an extremely small number of nano-objects.

  7. Metamaterial light sources driven by electron beams

    OpenAIRE

    ADAMO, G.; MacDonald, K. F.; De Angelis, F.; Di Fabrizio, E.; Zheludev, N. I.

    2011-01-01

    We demonstrate a new generation of free-space and fibre-coupled tuneable light sources based on nanostructured photonic metamaterials driven by free-electrons beams. Emission wavelengths are determined by metamaterial resonant modes and electron energies

  8. Multilayer Graphene for Waveguide Terahertz Modulator

    DEFF Research Database (Denmark)

    Khromova, I.; Andryieuski, Andrei; Lavrinenko, Andrei

    2014-01-01

    We study terahertz to infrared electromagnetic properties of multilayer graphene/dielectric artificial medium and present a novel concept of terahertz modulation at midinfrared wavelengths. This approach allows the realization of high-speed electrically controllable terahertz modulators based...... on hollow waveguide sections filled with multilayer graphene....

  9. REVIEW ARTICLE: Chiral metamaterials: simulations and experiments

    Science.gov (United States)

    Wang, Bingnan; Zhou, Jiangfeng; Koschny, Thomas; Kafesaki, Maria; Soukoulis, Costas M.

    2009-11-01

    Electromagnetic metamaterials are composed of periodically arranged artificial structures. They show peculiar properties, such as negative refraction and super-lensing, which are not seen in natural materials. The conventional metamaterials require both negative epsilon and negative μ to achieve negative refraction. Chiral metamaterial is a new class of metamaterials offering a simpler route to negative refraction. In this paper, we briefly review the history of metamaterials and the developments on chiral metamaterials. We study the wave propagation properties in chiral metamaterials and show that negative refraction can be realized in chiral metamaterials with a strong chirality, with neither epsilon nor μ negative required. We have developed a retrieval procedure, adopting a uniaxial bi-isotropic model to calculate the effective parameters such as n ± , κ, epsilon and μ of the chiral metamaterials. Our work on the design, numerical calculations and experimental measurements of chiral metamaterials is introduced. Strong chiral behaviors such as optical activity and circular dichroism are observed and negative refraction is obtained for circularly polarized waves in these chiral metamaterials. We show that 3D isotropic chiral metamaterials can eventually be realized.

  10. Dual broadband metamaterial absorber.

    Science.gov (United States)

    Kim, Young Ju; Yoo, Young Joon; Kim, Ki Won; Rhee, Joo Yull; Kim, Yong Hwan; Lee, YoungPak

    2015-02-23

    We propose polarization-independent and dual-broadband metamaterial absorbers at microwave frequencies. This is a periodic meta-atom array consisting of metal-dielectric-multilayer truncated cones. We demonstrate not only one broadband absorption from the fundamental magnetic resonances but additional broadband absorption in high-frequency range using the third-harmonic resonance, by both simulation and experiment. In simulation, the absorption was over 90% in 3.93-6.05 GHz, and 11.64-14.55 GHz. The corresponding experimental absorption bands over 90% were 3.88-6.08 GHz, 9.95-10.46 GHz and 11.86-13.84 GHz, respectively. The origin of absorption bands was elucidated. Furthermore, it is independent of polarization angle owing to the multilayered circular structures. The design is scalable to smaller size for the infrared and the visible ranges.

  11. Universal metamaterial absorbe

    CERN Document Server

    Smaali, Rafik; Moreau, Antoine; Taliercio, Thierry; Centeno, Emmanuel

    2016-01-01

    We propose a design for an universal absorber, characterized by a resonance frequency that can be tuned from visible to microwave frequencies independently of the choice of the metal and the dielectrics involved. An almost resonant perfect absorption up to 99.8 % is demonstrated at resonance for all polarization states of light and for a very wide angular aperture. These properties originate from a magnetic Fabry-Perot mode that is confined in a dielectric spacer of $\\lambda/100$ thickness by a metamaterial layer and a mirror. An extraordinary large funneling through nano-slits explains how light can be trapped in the structure. Simple scaling laws can be used as a recipe to design ultra-thin perfect absorbers whatever the materials and the desired resonance wavelength, making our design truly universal.

  12. Waves in metamaterials

    CERN Document Server

    Solymar, Laszlo

    2014-01-01

    Metamaterials is a young subject born in the 21st century. It is concerned with artificial materials which can have electrical and magnetic properties difficult or impossible to find in nature. The building blocks in most cases are resonant elements much smaller than the wavelength of the electromagnetic wave. The book offers a comprehensive treatment of all aspects of research in this field at a level that should appeal to final year undergraduates in physics or in electrical and electronic engineering. The mathematics is kept at a minimum; the aim is to explain the physics in simple terms and enumerate the major advances. It can be profitably read by graduate and post-graduate students in order to find out what has been done in the field outside their speciality, and by experts who may gain new insight about the inter-relationship of the physical phenomena involved.

  13. Metamaterials for perfect absorption

    CERN Document Server

    Lee, Young Pak; Yoo, Young Joon; Kim, Ki Won

    2016-01-01

    This book provides a comprehensive overview of the theory and practical development of metamaterial-based perfect absorbers (MMPAs). It begins with a brief history of MMPAs which reviews the various theoretical and experimental milestones in their development. The theoretical background and fundamental working principles of MMPAs are then discussed, providing the necessary background on how MMPAs work and are constructed. There then follows a section describing how different MMPAs are designed and built according to the operating frequency of the electromagnetic wave, and how their behavior is changed. Methods of fabricating and characterizing MMPAs are then presented. The book elaborates on the performance and characteristics of MMPAs, including electromagnetically-induced transparency (EIT). It also covers recent advances in MMPAs and their applications, including multi-band, broadband, tunability, polarization independence and incidence independence. Suitable for graduate students in optical sciences and e...

  14. Doped Chiral Polymer Metamaterials

    Science.gov (United States)

    Park, Cheol (Inventor); Kang, Jin Ho (Inventor); Gordon, Keith L. (Inventor); Sauti, Godfrey (Inventor); Lowther, Sharon E. (Inventor); Bryant, Robert G. (Inventor)

    2017-01-01

    Some implementations provide a composite material that includes a first material and a second material. In some implementations, the composite material is a metamaterial. The first material includes a chiral polymer (e.g., crystalline chiral helical polymer, poly-.gamma.-benzyl-L-glutamate (PBLG), poly-L-lactic acid (PLA), polypeptide, and/or polyacetylene). The second material is within the chiral polymer. The first material and the second material are configured to provide an effective index of refraction value for the composite material of 1 or less. In some implementations, the effective index of refraction value for the composite material is negative. In some implementations, the effective index of refraction value for the composite material of 1 or less is at least in a wavelength of one of at least a visible spectrum, an infrared spectrum, a microwave spectrum, and/or an ultraviolet spectrum.

  15. High-Q photonic crystal cavities in all-semiconductor photonic crystal heterostructures

    Science.gov (United States)

    Bushell, Z. L.; Florescu, M.; Sweeney, S. J.

    2017-06-01

    Photonic crystal cavities enable the realization of high Q-factor and low mode-volume resonators, with typical architectures consisting of a thin suspended periodically patterned layer to maximize confinement of light by strong index guiding. We investigate a heterostructure-based approach comprising a high refractive index core and lower refractive index cladding layers. While confinement typically decreases with decreasing index contrast between the core and cladding layers, we show that, counterintuitively, due to the confinement provided by the photonic band structure in the cladding layers, it becomes possible to achieve Q factors >104 with only a small refractive index contrast. This opens up opportunities for implementing high-Q factor cavities in conventional semiconductor heterostructures, with direct applications to the design of electrically pumped nanocavity lasers using conventional fabrication approaches.

  16. The Design of High-Q Sallen-Key Biquads with Unity-Gain Buffer Amplifiers

    DEFF Research Database (Denmark)

    Gaunholt, Hans; Guldbrandsen, Birthe

    1997-01-01

    and to implement the Sallen- Key biquad even in the high-Q case with reasonable sensitivities. The method is based on the unity gain version of the biquad and as unity gain buffer amplifiers are readily manufactured in integrated circuit technology the results may be very useful in the fabrication of integrated...... analog filters in voltage-mode as well as current-mode technology. As an example we will choose the band-pass biquad as biquads of this type often has to be designed with high-Q values. The results in the band-pass case may readily be transferred to the low-pass and high-pass cases....

  17. Metasurfaces in terahertz waveband

    Science.gov (United States)

    He, Jingwen; Zhang, Yan

    2017-11-01

    Metasurface, composed of subwavelength antennas, allows us to obtain arbitrary permittivity and permeability in electromagnetic (EM) waveband. It can be used to control the polarization, frequency, amplitude, and phase of the EM wave. Conventional terahertz (THz) components, such as high-impedance silicon lens, polyethylene lens, and quartz wave plate, rely on the phase accumulation along the wave propagation to reshape the THz wavefront. The metasurface employs the localized surface plasmon resonance to modulate the wavefront. Compared with conventional THz components, metasurface has the advantages of being ultrathin, ultralight, and low cost. In recent years, a large number of THz devices based on metasurface have been proposed. We review in broad outline the metasurface devices in the THz region and describe the progress of static and tunable THz field-modulated metasurfaces in detail. Finally, we discuss current challenges and opportunities in this rapidly developing research field.

  18. First-principles method for high-$Q$ photonic crystal cavity mode calculations

    CERN Document Server

    Mahmoodian, Sahand; Poulton, Christopher G; Dossou, Kokou B; Botten, Lindsay C; McPhedran, Ross C; de Sterke, C Martijn

    2012-01-01

    We present a first-principles theory to compute radiation properties of ultra-high quality factor photonic crystal (PC) cavities using a basis of bound PC waveguide states. This method is used to compute the far-field radiation pattern and quality factor of cavity modes $\\sim 100$ times more rapidly than conventional finite-difference time domain methods. Our method provides a simple rule for engineering the PC cavity far-field radiation pattern in high $Q$ cavities.

  19. STIR-Physics: Cold Atoms and Nanocrystals in Tapered Nanofiber and High-Q Resonator Potentials

    Science.gov (United States)

    2016-11-02

    STIR-Physics: Cold Atoms and Nanocrystals in Tapered Nanofiber and High-Q Resonator Potentials We worked on a tapered fiber in cold atomic cloud...setup. At the end of this program, we had built the vacuum system, specialized cold atom chamber and were working on the fiber epoxy mount for the...Triangle Park, NC 27709-2211 Tapered Fibers, Cold atoms , Nonlinear Optics REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 10. SPONSOR

  20. Metamaterial, plasmonic and nanophotonic devices.

    Science.gov (United States)

    Monticone, Francesco; Alù, Andrea

    2017-03-01

    The field of metamaterials has opened landscapes of possibilities in basic science, and a paradigm shift in the way we think about and design emergent material properties. In many scenarios, metamaterial concepts have helped overcome long-held scientific challenges, such as the absence of optical magnetism and the limits imposed by diffraction in optical imaging. As the potential of metamaterials, as well as their limitations, become clearer, these advances in basic science have started to make an impact on several applications in different areas, with far-reaching implications for many scientific and engineering fields. At optical frequencies, the alliance of metamaterials with the fields of plasmonics and nanophotonics can further advance the possibility of controlling light propagation, radiation, localization and scattering in unprecedented ways. In this review article, we discuss the recent progress in the field of metamaterials, with particular focus on how fundamental advances in this field are enabling a new generation of metamaterial, plasmonic and nanophotonic devices. Relevant examples include optical nanocircuits and nanoantennas, invisibility cloaks, superscatterers and superabsorbers, metasurfaces for wavefront shaping and wave-based analog computing, as well as active, nonreciprocal and topological devices. Throughout the paper, we highlight the fundamental limitations and practical challenges associated with the realization of advanced functionalities, and we suggest potential directions to go beyond these limits. Over the next few years, as new scientific breakthroughs are translated into technological advances, the fields of metamaterials, plasmonics and nanophotonics are expected to have a broad impact on a variety of applications in areas of scientific, industrial and societal significance.

  1. Nonlinear Optical Terahertz Technology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Our approach is based on high-Q optical WGM resonators made with a nonlinear crystal. Such resonators have been demonstrated to dramatically enhance nonlinear...

  2. All-optical tunable buffering with coupled ultra-high Q whispering gallery mode microcavities.

    Science.gov (United States)

    Yoshiki, Wataru; Honda, Yoshihiro; Tetsumoto, Tomohiro; Furusawa, Kentaro; Sekine, Norihiko; Tanabe, Takasumi

    2017-09-06

    All-optical tunable buffering was recently achieved on a chip by using dynamically tuned coupled mode induced transparency, which is an optical analogue of electromagnetically induced transparency. However, the small Q s of about 105 used in those systems were limiting the maximum buffering time to a few hundred ps. Although employing an ultra-high Q whispering gallery mode (WGM) microcavity can significantly improve the maximum buffering time, the dynamic tuning of the WGM has remained challenging because thermo-optic and pressure tunings, which are widely used for WGM microcavities, have a very slow response. Here we demonstrate all-optical tunable buffering utilizing coupled ultra-high Q WGM cavities and the Kerr effect. The Kerr effect can change the refractive index instantaneously, and this allowed us to tune the WGM cavity very quickly. In addition, from among the various WGM cavities we employed a silica toroid microcavity for our experiments because it has an ultra-high Q factor (>2 × 107) and a small mode volume, and can be fabricated on a chip. Use of the Kerr effect and the silica toroid microcavity enabled us to observe an on-chip all-optical tunable buffering operation and achieve a maximum buffering time of 20 ns.

  3. Microwave diode switchable metamaterial reflector/absorber

    Science.gov (United States)

    Xu, Wangren; Sonkusale, Sameer

    2013-07-01

    We embed diodes as active circuit elements within a metamaterial to implement a switchable metamaterial reflector/absorber at microwave frequencies. Diodes are placed in series with the unit cells of the metamaterial array. This results in just a pair of control lines to actively tune all the diodes in a metamaterial. Diodes can be tuned on and off to switch the function of the metamaterial between a perfect absorber and a reflector. The design, simulation, and experimental results of a switchable reflector/absorber in 2-6 GHz range are presented.

  4. Perfect selective metamaterial solar absorbers.

    Science.gov (United States)

    Wang, Hao; Wang, Liping

    2013-11-04

    In this work, we numerically investigate the radiative properties of metamaterial nanostructures made of two-dimensional tungsten gratings on a thin dielectric spacer and an opaque tungsten film from UV to mid-infrared region as potential selective solar absorbers. The metamaterial absorber with single-sized tungsten patches exhibits high absorptance in the visible and near-infrared region due to several mechanisms such as surface plasmon polaritons, magnetic polaritons, and intrinsic bandgap absorption of tungsten. Geometric effects on the resonance wavelengths and the absorptance spectra are studied, and the physical mechanisms are elucidated in detail. The absorptance could be further enhanced in a broader spectral range with double-sized metamaterial absorbers. The total solar absorptance of the optimized metamaterial absorbers at normal incidence could be more than 88%, while the total emittance is less than 3% at 100°C, resulting in total photon-to-heat conversion efficiency of 86% without any optical concentration. Moreover, the metamaterial solar absorbers exhibit quasi-diffuse behaviors as well as polarization independence. The results here will facilitate the design of novel highly efficient solar absorbers to enhance the performance of various solar energy conversion systems.

  5. Controlling sound with acoustic metamaterials

    Science.gov (United States)

    Cummer, Steven A.; Christensen, Johan; Alù, Andrea

    2016-03-01

    Acoustic metamaterials can manipulate and control sound waves in ways that are not possible in conventional materials. Metamaterials with zero, or even negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales. The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. Active acoustic metamaterials use external control to create effective material properties that are not possible with passive structures and have led to the development of dynamically reconfigurable, loss-compensating and parity-time-symmetric materials for sound manipulation. Challenges remain, including the development of efficient techniques for fabricating large-scale metamaterial structures and converting laboratory experiments into useful devices. In this Review, we outline the designs and properties of materials with unusual acoustic parameters (for example, negative refractive index), discuss examples of extreme manipulation of sound and, finally, provide an overview of future directions in the field.

  6. Multi-band slow light metamaterial.

    Science.gov (United States)

    Zhu, Lei; Meng, Fan-Yi; Fu, Jia-Hui; Wu, Qun; Hua, Jun

    2012-02-13

    In this paper, a multi-band slow light metamaterial is presented and investigated. The metamaterial unit cell is composed of three cut wires of different sizes and parallel to each other. Two transparency windows induced by two-two overlaps of absorption bands of three cut wires are observed. The multi-band transmission characteristics and the slow light properties of metamaterial are verified by numerical simulation, which is in a good agreement with theoretical predictions. The impacts of structure parameters on transparency windows are also investigated. Simulation results show the spectral properties can be tuned by adjusting structure parameters of metamaterial. The equivalent circuit model and the synthesis method of the multi-band slow light metamaterial are presented. It is seen from simulation results that the synthesis method accurately predicts the center frequency of the multi-band metamaterial, which opens a door to a quick and accurate construction for multi-band slow light metamaterial.

  7. Room temperature detector array technology for the terahertz to far-infrared.

    Energy Technology Data Exchange (ETDEWEB)

    Camacho, Ryan; Shaw, Michael; Zhang, X.; Tao, Hu; Lentine, Anthony L.; Wright, Jeremy Benjamin; Shaner, Eric Arthur; Trotter, Douglas Chandler; Averitt, Richard D.; Kadlec, Emil G; Rakich, Peter T.

    2011-10-01

    Thermal detection has made extensive progress in the last 40 years, however, the speed and detectivity can still be improved. The advancement of silicon photonic microring resonators has made them intriguing for detection devices due to their small size and high quality factors. Implementing silicon photonic microring or microdisk resonators as a means of a thermal detector gives rise to higher speed and detectivity, as well as lower noise compared to conventional devices with electrical readouts. This LDRD effort explored the design and measurements of silicon photonic microdisk resonators used for thermal detection. The characteristic values, consisting of the thermal time constant ({tau} {approx} 2 ms) and noise equivalent power were measured and found to surpass the performance of the best microbolometers. Furthermore the detectivity was found to be D{sub {lambda}} = 2.47 x 10{sup 8} cm {center_dot} {radical}Hz/W at 10.6 {mu}m which is comparable to commercial detectors. Subsequent design modifications should increase the detectivity by another order of magnitude. Thermal detection in the terahertz (THz) remains underdeveloped, opening a door for new innovative technologies such as metamaterial enhanced detectors. This project also explored the use of metamaterials in conjunction with a cantilever design for detection in the THz region and demonstrated the use of metamaterials as custom thin film absorbers for thermal detection. While much work remains to integrate these technologies into a unified platform, the early stages of research show promising futures for use in thermal detection.

  8. Family of graphene-assisted resonant surface optical excitations for terahertz devices

    Science.gov (United States)

    Lin, I.-Tan; Liu, Jia-Ming; Tsai, Hsin-Cheng; Wu, Kaung-Hsiung; Syu, Jheng-Yuan; Su, Ching-Yuan

    2016-10-01

    The majority of the proposed graphene-based THz devices consist of a metamaterial that can optically interact with graphene. This coupled graphene-metamaterial system gives rise to a family of resonant modes such as the surface plasmon polariton (SPP) modes of graphene, the geometrically induced SPPs, also known as the spoof SPP modes, and the Fabry-Perot (FP) modes. In the literature, these modes are usually considered separately as if each could only exist in one structure. By contrast, in this paper, we show that even in a simple metamaterial structure such as a one-dimensional (1D) metallic slit grating, these modes all exist and can potentially interact with each other. A graphene SPP-based THz device is also fabricated and measured. Despite the high scattering rate, the effective SPP resonances can still be observed and show a consistent trend between the effective frequency and the grating period, as predicted by the theory. We also find that the excitation of the graphene SPP mode is most efficient in the terahertz spectral region due to the Drude conductivity of graphene in this spectral region.

  9. Numerical methods for metamaterial design

    CERN Document Server

    2013-01-01

    This book describes a relatively new approach for the design of electromagnetic metamaterials.  Numerical optimization routines are combined with electromagnetic simulations to tailor the broadband optical properties of a metamaterial to have predetermined responses at predetermined wavelengths. After a review of both the major efforts within the field of metamaterials and the field of mathematical optimization, chapters covering both gradient-based and derivative-free design methods are considered.  Selected topics including surrogate-base optimization, adaptive mesh search, and genetic algorithms are shown to be effective, gradient-free optimization strategies.  Additionally, new techniques for representing dielectric distributions in two dimensions, including level sets, are demonstrated as effective methods for gradient-based optimization.  Each chapter begins with a rigorous review of the optimization strategy used, and is followed by numerous examples that combine the strategy with either electromag...

  10. Electrically tunable infrared metamaterial devices

    Science.gov (United States)

    Brener, Igal; Jun, Young Chul

    2015-07-21

    A wavelength-tunable, depletion-type infrared metamaterial optical device is provided. The device includes a thin, highly doped epilayer whose electrical permittivity can become negative at some infrared wavelengths. This highly-doped buried layer optically couples with a metamaterial layer. Changes in the transmission spectrum of the device can be induced via the electrical control of this optical coupling. An embodiment includes a contact layer of semiconductor material that is sufficiently doped for operation as a contact layer and that is effectively transparent to an operating range of infrared wavelengths, a thin, highly doped buried layer of epitaxially grown semiconductor material that overlies the contact layer, and a metallized layer overlying the buried layer and patterned as a resonant metamaterial.

  11. Nonlinear, tunable and active metamaterials

    CERN Document Server

    Lapine, Mikhail; Kivshar, Yuri

    2015-01-01

    Metamaterials, artificial electromagnetic media achieved by structuring on the subwave-length-scale were initially suggested for the negative index and superlensing. They became a paradigm for engineering electromagnetic space and controlling propagation of waves. The research agenda is now shifting on achieving tuneable, switchable, nonlinear and sensing functionalities. The time has come to talk about the emerging research field of metadevices employing active and tunable metamaterials with unique functionalities achieved by structuring of functional matter on the subwave-length scale. This book presents the first systematic and comprehensive summary of the reviews written by the pioneers and top-class experts in the field of metamaterials. It addresses many grand challenges of the cutting edge research for creating smaller and more efficient photonic structures and devices.

  12. A programmable nonlinear acoustic metamaterial

    Science.gov (United States)

    Yang, Tianzhi; Song, Zhi-Guang; Clerkin, Eoin; Zhang, Ye-Wei; Sun, Jia-He; Su, Yi-Shu; Chen, Li-Qun; Hagedorn, Peter

    2017-09-01

    Acoustic metamaterials with specifically designed lattices can manipulate acoustic/elastic waves in unprecedented ways. Whereas there are many studies that focus on passive linear lattice, with non-reconfigurable structures. In this letter, we present the design, theory and experimental demonstration of an active nonlinear acoustic metamaterial, the dynamic properties of which can be modified instantaneously with reversibility. By incorporating active and nonlinear elements in a single unit cell, a real-time tunability and switchability of the band gap is achieved. In addition, we demonstrate a dynamic "editing" capability for shaping transmission spectra, which can be used to create the desired band gap and resonance. This feature is impossible to achieve in passive metamaterials. These advantages demonstrate the versatility of the proposed device, paving the way toward smart acoustic devices, such as logic elements, diode and transistor.

  13. Terahertz Science, Technology, and Communication

    Science.gov (United States)

    Chattopadhyay, Goutam

    2013-01-01

    The term "terahertz" has been ubiquitous in the arena of technology over the past couple of years. New applications are emerging every day which are exploiting the promises of terahertz - its small wavelength; capability of penetrating dust, clouds, and fog; and possibility of having large instantaneous bandwidth for high-speed communication channels. Until very recently, space-based instruments for astrophysics, planetary science, and Earth science missions have been the primary motivator for the development of terahertz sensors, sources, and systems. However, in recent years the emerging areas such as imaging from space platforms, surveillance of person-borne hidden weapons or contraband from a safe stand-off distance and reconnaissance, medical imaging and DNA sequencing, and in the world high speed communications have been the driving force for this area of research.

  14. Computational and theoretical investigation of micro- and nano-scale chiral electromagnetic metamaterials

    Science.gov (United States)

    Wongkasem, Nantakan

    metamaterials, which, besides providing magnetoelectric coupling, have a negative refractive index passband which can easily be tuned in both the frequency of operation and bandwidth. Moreover, the transmission bands can be generated over a broad frequency regime with a lower loss than other known chiral structures e.g. omega, gammadion, and the NRI metamaterial, e.g. the "S-shaped" resonator. The design methodology for the novel metamaterials development is presented. Proof of the negative refractive index of the proposed structure, through simulation, using a wedge model and a triangle-shaped structure of the design, is also provided. Furthermore, a couple of the metamaterial designs are fabricated and tested in the microwave regime for validation purposes. Circuit analysis is applied to design the negative index property. Group theory is used to derive material properties which are then used to analyze the magnetoelectric coupling of this design. Co- and cross-polarizations from the experimental and numerical results in the terahertz regime are discussed. Advantages and disadvantages of our novel chiral NRI structures are compared to those of the other recognized structures previously mentioned. The complimentary synthesis and modeling techniques of our novel chiral NRI metamaterials provide a guide to the optimization of metamaterial designs in the near-IR and visible frequency regime.

  15. A metamaterial for directive emission.

    Science.gov (United States)

    Enoch, Stefan; Tayeb, Gérard; Sabouroux, Pierre; Guérin, Nicolas; Vincent, Patrick

    2002-11-18

    In this paper we present the first results on emission in metamaterial. We show how the specific properties of metallic composite material can modify the emission of an embedded source. We show that under proper conditions the energy radiated by a source embedded in a slab of metamaterial will be concentrated in a narrow cone in the surrounding media. An experimental demonstration of this effect is given in the microwave domain, and the constructed antenna has a directivity equivalent to the best reported results with photonic-crystal-based antennas but using a completely different physical principle [B. Temelkuaran, J. Appl. Phys. 87, 603 (2000)

  16. Broadband terahertz fiber directional coupler

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Rasmussen, Henrik K.; Jepsen, Peter Uhd

    2010-01-01

    We present the design of a short broadband fiber directional coupler for terahertz (THz) radiation and demonstrate a 3 dB coupler with a bandwidth of 0:6 THz centered at 1:4 THz. The broadband coupling is achieved by mechanically downdoping the cores of a dual-core photonic crystal fiber by micro......We present the design of a short broadband fiber directional coupler for terahertz (THz) radiation and demonstrate a 3 dB coupler with a bandwidth of 0:6 THz centered at 1:4 THz. The broadband coupling is achieved by mechanically downdoping the cores of a dual-core photonic crystal fiber...

  17. A terahertz grid frequency doubler

    OpenAIRE

    Moussessian, Alina; Wanke, Michael C.; Li, Yongjun; Chiao, Jung-Chih; Allen, S. James; Crowe, Thomas W.; Rutledge, David B.

    1998-01-01

    We present a 144-element terahertz quasi-optical grid frequency doubler. The grid is a planar structure with bow-tie antennas as a unit cell, each loaded with a planar Schottky diode. The maximum output power measured for this grid is 24 mW at 1 THz for 3.1-μs 500-GHz input pulses with a peak input power of 47 W. An efficiency of 0.17% for an input power of 6.3 W and output power of 10.8 mW is measured. To date, this is the largest recorded output power for a multiplier at terahertz frequenci...

  18. Topological Gyroscopic Metamaterials

    Science.gov (United States)

    Nash, Lisa Michelle

    Topological materials are generally insulating in their bulk, with protected conducting states on their boundaries that are robust against disorder and perturbation of material property. The existence of these conducting edge states is characterized by an integer topological invariant. Though the phenomenon was first discovered in electronic systems, recent years have shown that topological states exist in classical systems as well. In this thesis we are primarily concerned with the topological properties of gyroscopic materials, which are created by coupling networks of fast-spinning objects. Through a series of simulations, numerical calculations, and experiments, we show that these materials can support topological edge states. We find that edge states in these gyroscopic metamaterials bear the hallmarks of topology related to broken time reversal symmetry: they transmit excitations unidirectionally and are extremely robust against experimental disorder. We also explore requirements for topology by studying several lattice configurations and find that topology emerges naturally in gyroscopic systems.A simple prescription can be used to create many gyroscopic lattices. Though many of our gyroscopic networks are periodic, we explore amorphous point-sets and find that topology also emerges in these networks.

  19. Applications of High-Q Microresonators in Cavity Optomechanics and Nonlinear Photonics

    Science.gov (United States)

    Jiang, Wei C.

    Optical microresonators confining light to small volumes are indispensable for a great variety of studies and applications. This thesis is devoted to a study of cavity optomechanical and nonlinear optical phenomena in high-Q microresonators with different materials and structures. Based on that, it proposes and demonstrates several novel schemes and device platforms that exhibit great potential for various applications ranging from frequency metrology and quantum photonics, to information processing and sensing. The thesis starts with a demonstration of a high-frequency (above 1 GHz) regenerative optomechanical oscillator based on a 2-mum-radius high-Q silicon microdisk resonator in the silicon-on-insulator platform with an ultra-low threshold pump power at room temperature and atmosphere. It then continues to explore the cavity optomechanics in single-crystal lithium niobate. A compact lithium niobate microdisk optomechanical resonator with high optical and mechanical qualities, large optomechanical coupling, and high mechanical frequency is achieved, enabling the demonstration of regenerative oscillation in the ambience. Meanwhile, I propose and investigate a novel approach for single molecule detection that utilizes the optical spring effect in a high-Q coherent optomechanical oscillator to dramatically enhance the sensing resolution by orders of magnitude compared with conventional resonator-based approaches. In particular, a high-Q silica microsphere is employed to experimentally demonstrate the detection of single Bovine Serum Albumin proteins with a molecular weight of 66 kDalton at a signal-to-noise ratio of 16.8. On the other hand, the thesis focuses on the theoretical and experimental investigation of the generation of high-purity bright photon pairs in a silicon microdisk based on the cavity enhanced four-wave mixing. The device is able to produce multiple photon pairs at different wavelengths in the telecom band with a high spectral brightness of 6.24 x

  20. Coupled high Q-factor Surface Nanoscale Axial Photonics (SNAP) microresonators

    CERN Document Server

    Sumetsky, M; DiGiovanni, D J; Dulashko, Y; Fini, J M; Monberg, E

    2011-01-01

    We experimentally demonstrate series of identical two, three, and five coupled high Q-factor Surface Nanoscale Axial Photonics (SNAP) microresonators formed by periodic nanoscale variation of the optical fiber radius. These microresonators are fabricated with a 100 \\mum period along an 18 \\mum radius optical fiber. The axial FWHM of these microresonators is 80 \\mum and their Q-factor exceeds 107. In addition, we demonstrate a SNAP microresonator with the axial FWHM as small as 30 \\mum and the axial FWHM of the fundamental mode as small as 10 \\mum. These results may potentially enable the dense integration of record low loss coupled photonic microdevices on the optical fiber platform.

  1. Two-dimensional Josephson junction arrays coupled through a high-Q cavity

    DEFF Research Database (Denmark)

    Filatrella, G.; Pedersen, Niels Falsig; Wiesenfeld, K.

    2001-01-01

    The problem of disordered two-dimensional arrays of underdamped Josephson junctions is addressed. Our simulations show that when coupled to a high-Q cavity, the array exhibits synchronized behavior, and the power emitted can be considerably increased once enough junctions are activated to pump...... emission frequency of the junctions and the cavity resonant frequency. We show with a simple argument that we can predict the scaling behavior of disorder with the size of the array. The consequences for the design of microwave oscillators in the Gigahertz region are discussed...

  2. Numerical and Experimental Study of the Q Factor of High-Q Micropillar Cavities

    DEFF Research Database (Denmark)

    Gregersen, Niels; Reitzenstein, S.; Kistner, C.

    2010-01-01

    Micropillar cavities are potential candidates for high-efficiency single-photon sources and are testbeds for cavity quantum electrodynamics experiments. In both applications a high quality (Q) factor is desired. It was recently shown that the Q of high-Q semiconductor micropillar cavities exhibit...... to the effective reflectivity of the fundamental mode arising from coupling to scattering channels involving higher-order cavity modes and propagating Bloch modes in the distributed Bragg reflectors (DBRs). We show how these weak contributions lead to strong variations of the Q factor, and we relate the average...

  3. Charged Particle Production in High Q2 Deep-Inelastic Scattering at HERA

    CERN Document Server

    Aaron, F.D.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smiljanic, Ivan; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2007-01-01

    The average charged track multiplicity and the normalised distribution of the scaled momentum, $\\xp$, of charged final state hadrons are measured in deep-inelastic $\\ep$ scattering at high $Q^2$ in the Breit frame of reference. The analysis covers the range of photon virtuality $100 < Q^2 < 20 000 \\GeV^{2}$. Compared with previous results presented by HERA experiments this analysis has a significantly higher statistical precision and extends the phase space to higher $Q^{2}$ and to the full range of $\\xp$. The results are compared with $e^+e^-$ annihilation data and with various calculations based on perturbative QCD using different models of the hadronisation process.

  4. High-Q X-band distributed Bragg resonator utilizing an aperiodic alumina plate arrangement.

    Science.gov (United States)

    Bale, Simon; Everard, Jeremy

    2010-01-01

    This paper describes a high-Q X-band distributed Bragg resonator that uses an aperiodic arrangement of non-lambda/4 low loss alumina plates mounted in a cylindrical waveguide. An ABCD parameter waveguide model was developed to simulate and optimize the cavity. The dielectric plates and air waveguide dimensions were optimized to achieve maximum quality factor by redistributing the energy loss within the cavity. An unloaded quality factor (Q(0)) of 196,000 was demonstrated at 9.93 GHz.

  5. Graphene-based extremely wide-angle tunable metamaterial absorber

    National Research Council Canada - National Science Library

    Linder, Jacob; Halterman, Klaus

    2016-01-01

    We investigate the absorption properties of graphene-based anisotropic metamaterial structures where the metamaterial layer possesses an electromagnetic response corresponding to a near-zero permittivity...

  6. Optical forces in nanorod metamaterial.

    Science.gov (United States)

    Bogdanov, Andrey A; Shalin, Alexander S; Ginzburg, Pavel

    2015-10-30

    Optomechanical manipulation of micro and nano-scale objects with laser beams finds use in a large span of multidisciplinary applications. Auxiliary nanostructuring could substantially improve performances of classical optical tweezers by means of spatial localization of objects and intensity required for trapping. Here we investigate a three-dimensional nanorod metamaterial platform, serving as an auxiliary tool for the optical manipulation, able to support and control near-field interactions and generate both steep and flat optical potential profiles. It was shown that the 'topological transition' from the elliptic to hyperbolic dispersion regime of the metamaterial, usually having a significant impact on various light-matter interaction processes, does not strongly affect the distribution of optical forces in the metamaterial. This effect is explained by the predominant near-fields contributions of the nanostructure to optomechanical interactions. Semi-analytical model, approximating the finite size nanoparticle by a point dipole and neglecting the mutual re-scattering between the particle and nanorod array, was found to be in a good agreement with full-wave numerical simulation. In-plane (perpendicular to the rods) trapping regime, saddle equilibrium points and optical puling forces (directed along the rods towards the light source), acting on a particle situated inside or at the nearby the metamaterial, were found.

  7. Metamaterial hyperlens for the MIR

    DEFF Research Database (Denmark)

    Hayashi, J. G.; Lwin, R.; Stefani, Alessio

    2016-01-01

    We report the first metamaterial tapered hyperlens for operation in the mid-infrared (3 μm) made of 470 tin wires embedded in soda-lime glass. The taper presents a magnification of 2x and is 62.5 μm in length. The structure on the smallest side has an average wire diameter and spacing of 300...

  8. Engineering resonances in infrared metamaterials.

    Science.gov (United States)

    Kanté, Boubacar; de Lustrac, André; Lourtioz, Jean-Michel; Gadot, Frédérique

    2008-05-12

    Engineering resonances in metamaterials has been so far the main way of reaching simultaneously negative permittivity and negative permeability leading to negative index materials. In this paper, we present an experimental and numerical analysis of the infrared response of metamaterials made of continuous nanowires and split ring resonators (SRR) deposited on low-doped silicon when the geometry of the SRRs is gradually altered. The impact of the geometric transformation of the SRRs on the spectra of the composite metamaterial is measured in the 20-200 THz frequency range (i.e., in the 1.5-15 microm wavelength range) for the two field polarizations under normal to plane propagation. We show experimentally and numerically that tuning the SRRs towards elementary cut wires translates in a predictable manner the frequency response of the artificial material. We also analyze coupling effects between the SRRs and the continuous nanowires for different spacings between them. The results of our study are expected to provide useful guidelines for the design of negative index metamaterials on silicon.

  9. Homogenization scheme for acoustic metamaterials

    KAUST Repository

    Yang, Min

    2014-02-26

    We present a homogenization scheme for acoustic metamaterials that is based on reproducing the lowest orders of scattering amplitudes from a finite volume of metamaterials. This approach is noted to differ significantly from that of coherent potential approximation, which is based on adjusting the effective-medium parameters to minimize scatterings in the long-wavelength limit. With the aid of metamaterials’ eigenstates, the effective parameters, such as mass density and elastic modulus can be obtained by matching the surface responses of a metamaterial\\'s structural unit cell with a piece of homogenized material. From the Green\\'s theorem applied to the exterior domain problem, matching the surface responses is noted to be the same as reproducing the scattering amplitudes. We verify our scheme by applying it to three different examples: a layered lattice, a two-dimensional hexagonal lattice, and a decorated-membrane system. It is shown that the predicted characteristics and wave fields agree almost exactly with numerical simulations and experiments and the scheme\\'s validity is constrained by the number of dominant surface multipoles instead of the usual long-wavelength assumption. In particular, the validity extends to the full band in one dimension and to regimes near the boundaries of the Brillouin zone in two dimensions.

  10. Quantum informatics with plasmonic metamaterials

    OpenAIRE

    Kamli, Ali A.; Moiseev, Sergey A.; Sanders, Barry C.

    2010-01-01

    Surface polaritons at a meta-material interface are proposed as qubits. The SP fields are shown to have low losses, subwavelength confinement and can demonstrate very small modal volume. These important properties are used to demonstatre interesting applications in quantum information, i.e., coherent control of weak fields and large Kerr nonlinearity at the low photon level.

  11. Mimicking Celestial Mechanics in Metamaterials

    Science.gov (United States)

    2009-09-01

    general theory of relativity is the bending of light that passes near massive celestial objects such as stars, nebulas or galaxies . This effect...optical metamaterial exhibiting negative refractive index. Nature 455, 376–379 (2008). 14. Shapiro, S. L. & Teukolsky, S. A.White Dwarfs , and Neutron

  12. Terahertz near-field microspectroscopy

    NARCIS (Netherlands)

    Knab, J.R.; Adam, A.J.L.; Chakkittakandy, R.; Planken, P.C.M.

    2010-01-01

    Using near-field, terahertz time-domain spectroscopy (THz-TDS), we investigate how the addition of a dielectric material into a subwavelength-diameter, cylindrical waveguide affects its transmission properties. The THz electric near-field is imaged with deep subwavelength resolution as it emerges

  13. Terahertz radar cross section measurements

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd

    2010-01-01

    We perform angle- and frequency-resolved radar cross section (RCS) measurements on objects at terahertz frequencies. Our RCS measurements are performed on a scale model aircraft of size 5-10 cm in polar and azimuthal configurations, and correspond closely to RCS measurements with conventional radar...

  14. Terahertz antenna technology for space applications

    CERN Document Server

    Choudhury, Balamati; Jha, Rakesh Mohan

    2016-01-01

    This book explores the terahertz antenna technology towards implementation of compact, consistent and cheap terahertz sources, as well as the high sensitivity terahertz detectors. The terahertz EM band provides a transition between the electronic and the photonic regions thus adopting important characteristics from these regimes. These characteristics, along with the progress in semiconductor technology, have enabled researchers to exploit hitherto unexplored domains including satellite communication, bio-medical imaging, and security systems. The advances in new materials and nanostructures such as graphene will be helpful in miniaturization of antenna technology while simultaneously maintaining the desired output levels. Terahertz antenna characterization of bandwidth, impedance, polarization, etc. has not yet been methodically structured and it continues to be a major research challenge. This book addresses these issues besides including the advances of terahertz technology in space applications worldwide,...

  15. Mass diffusion cloaking and focusing with metamaterials

    Science.gov (United States)

    Restrepo-Flórez, Juan Manuel; Maldovan, Martin

    2017-08-01

    Recent advances in the design of metamaterials that control diffusive transport processes have enabled efficient devices to manipulate heat conduction. In contrast, control of mass diffusion with metamaterial devices has been largely unexplored. Mass diffusion is critically important in multiple research areas ranging from electronic and energy materials to chemical and biological systems. In this work, we introduce a physical approach to design mass diffusion metamaterial devices that take into account the fundamental physical mechanisms behind mass transport. We demonstrate that mass concentration discontinuities arising from different material solubilities are critical physical factors that need to be incorporated for the accurate design and characterization of mass diffusion metamaterial devices. We employ our approach to devise and analyze cloaking and focusing of molecules and show how the difference in solubilities is critically important for the efficiency of the metamaterials. This work provides physical insights and guidelines to understand and design mass diffusion in metamaterial devices.

  16. Electrifying photonic metamaterials for tunable nonlinear optics.

    Science.gov (United States)

    Kang, Lei; Cui, Yonghao; Lan, Shoufeng; Rodrigues, Sean P; Brongersma, Mark L; Cai, Wenshan

    2014-08-11

    Metamaterials have not only enabled unprecedented flexibility in producing unconventional optical properties that are not found in nature, they have also provided exciting potential to create customized nonlinear media with high-order properties correlated to linear behaviour. Two particularly compelling directions are active metamaterials, whose optical properties can be purposely tailored by external stimuli in a reversible manner, and nonlinear metamaterials, which enable intensity-dependent frequency conversion of light waves. Here, by exploring the interaction of these two directions, we leverage the electrical and optical functions simultaneously supported in nanostructured metals and demonstrate electrically controlled nonlinear optical processes from a metamaterial. Both second harmonic generation and optical rectification, enhanced by the resonance behaviour in the metamaterial absorber, are modulated externally with applied voltage signals. Our results reveal an opportunity to exploit optical metamaterials as self-contained, dynamic electro-optic systems with intrinsically embedded electrical functions and optical nonlinearities.

  17. Casimir interactions between graphene sheets and metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Drosdoff, D.; Woods, Lilia M. [Department of Physics, University of South Florida, Tampa, Florida 33620 (United States)

    2011-12-15

    The Casimir force between graphene sheets and metamaterials is studied. Theoretical results based on the Lifshitz theory for layered, planar, two-dimensional systems in media are presented. We consider graphene-graphene, graphene-metamaterial, and metal-graphene-metamaterial configurations. We find that quantum effects of the temperature-dependent force are not apparent until the submicron range. In contrast to results with bulk dielectric and bulk metallic materials, no Casimir repulsion is found when graphene is placed on top of a magnetically active metamaterial substrate, regardless of the strength of the low-frequency magnetic response. In the case of the metal-graphene-metamaterial setting, repulsion between the metamaterial and the metal-graphene system is possible only when the dielectric response from the metal contributes significantly.

  18. Multiband Negative Permittivity Metamaterials and Absorbers

    Directory of Open Access Journals (Sweden)

    Yiran Tian

    2013-01-01

    Full Text Available Design and characteristics of multiband negative permittivity metamaterial and its absorber configuration are presented in this paper. The proposed multiband metamaterial is composed of a novel multibranch resonator which can possess four electric resonance frequencies. It is shown that, by controlling the length of the main branches of such resonator, the resonant frequencies and corresponding absorbing bands of metamaterial absorber can be shifted in a large frequency band.

  19. Active elastic metamaterials with applications in acoustics

    OpenAIRE

    Pope, Simon; Laalej, Hatim; Daley, Steve

    2012-01-01

    International audience; Elastic metamaterials provide a new approach to solving existing problems in acoustics. They have also been associated with novel concepts such as acoustic invisibility and subwavelength imaging. To be applied to many of the proposed applications a metamaterial would need to have the desired mass density and elastic moduli over a wide frequency band. To minimise scatter in acoustics applications the impedance of solid elastic metamaterials also need to be matched to th...

  20. Flexible frequency selective metamaterials for microwave applications

    Science.gov (United States)

    Gao, Bo; Yuen, Matthew M. F.; Ye, Terry Tao

    2017-03-01

    Metamaterials have attracted more and more research attentions recently. Metamaterials for electromagnetic applications consist of sub-wavelength structures designed to exhibit particular responses to an incident EM (electromagnetic) wave. Traditional EM (electromagnetic) metamaterial is constructed from thick and rigid structures, with the form-factor suitable for applications only in higher frequencies (above GHz) in microwave band. In this paper, we developed a thin and flexible metamaterial structure with small-scale unit cell that gives EM metamaterials far greater flexibility in numerous applications. By incorporating ferrite materials, the thickness and size of the unit cell of metamaterials have been effectively scaled down. The design, mechanism and development of flexible ferrite loaded metamaterials for microwave applications is described, with simulation as well as measurements. Experiments show that the ferrite film with permeability of 10 could reduce the resonant frequency. The thickness of the final metamaterials is only 0.3mm. This type of ferrite loaded metamaterials offers opportunities for various sub-GHz microwave applications, such as cloaks, absorbers, and frequency selective surfaces.

  1. Design of Fano Resonators for Novel Metamaterial Applications

    KAUST Repository

    Amin, Muhammad

    2014-05-01

    The term “metamaterials” refers to engineered structures that interact with electromagnetic fields in an unusual but controllable way that cannot be observed with natural materials. Metamaterial design at optical frequencies oftentimes makes of controllable plasmonic interactions. Light can excite collective oscillations of conduction band electrons on a metallic nanostructure. These oscillations result in localized surface plasmon modes which can provide high confinement of fields at metal-dielectric interfaces at nanoscale. Additionally scattering and absorption characteristics of plasmon modes can be controlled by geometrical features of the metallic nanostructures. This ease of controllability has lead to the development of new concepts in light manipulation and enhancement of light-material interactions. Fano resonance and plasmonic induced transparency (PIT) are among the most promising of those. The interference between different plasmon modes induced on nanostructures generates PIT/Fano resonance at optical frequencies. The unusual dispersion characteristics observed within the PIT window can be used for designing optical metamaterials to be used in various applications including bio-chemical sensing, slow light, modulation, perfect absorption, and all-optical switching. This thesis focuses on design of novel plasmonic devices to be used in these applications. The fundamental idea behind these designs is the generation of higher-order plasmon modes, which leads to PIT/Fano resonance-like output characteristics. These are then exploited together with dynamic tunability supported by graphene and field enhancement provided by nonlinear materials to prototype novel plasmonic devices. More specifically, this thesis proposes the following plasmonic device designs. I.\\tNano-disk Fano resonator: Open disk-like plasmonic nanostructures are preferred for bio-chemical sensing because of their higher capacity to be in contact with greater volumes of analyte. High

  2. Metamaterial-enabled transformation optics

    Science.gov (United States)

    Landy, Nathan

    Transformation Optics is a design methodology that uses the form invariance of Maxwell's equations to distort electromagnetic fields. This distortion is imposed on a region of space by mimicking a curvilinear coordinate system with prescribed magnetoelectric material parameters. By simply specifying the correct coordinate transformation, researchers have created such exotic devices as invisibility cloaks, ``perfect'' lenses, and illusion devices. Unfortunately, these devices typically require correspondingly exotic material parameters that do not occur in Nature. Researchers have therefore turned to complex artificial media known as metamaterials to approximate the desired responses. However, the metamaterial design process is complex, and there are limitations on the responses that they achieve. In this dissertation, we explore both the applicability and limitations of metamaterials in Transformation Optics design. We begin in Chapter 2 by investigating the freedoms available to use in the transformation optics design process itself. We show that quasi-conformal mappings may be used to alleviate some of the complexity of material design in both two- and three-dimensional design. We then go on in Chapter 3 to apply this method to the design of a transformation-optics modified optic. We show that even a highly-approximate implementation of such a lens would retain many of the key performance feautures that we would expect from a full material prescription. However, the approximations made in the design of our lens may not be valid in other areas of transformation optical design. For instance, the high-frequency approximations of our lens design ignore the effects of impedance mismatch, and the approximation is not valid when the material parameters vary on the order of a wavelength. Therefore, in Chapter 4 we use other freedoms available to us to design a full-parameter cloak of invisibility. By tailoring the electromagnetic environment of our cloak, we are able to

  3. Charged particle production in high Q{sup 2} deep-inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Aktas, A. [DESY, Hamburg (DE)] (and others)

    2007-05-15

    The average charged track multiplicity and the normalised distribution of the scaled momentum, x{sub p}, of charged final state hadrons are measured in deep-inelastic ep scattering at high Q{sup 2} in the Breit frame of reference. The analysis covers the range of photon virtuality 100 < Q{sup 2} < 20 000 GeV{sup 2}. Compared with previous results presented by HERA experiments this analysis has a significantly higher statistical precision and extends the phase space to higher Q{sup 2} and to the full range of x{sub p}. The results are compared with e{sup +}e{sup -} annihilation data and with various calculations based on perturbative QCD using different models of the hadronisation process. (orig.)

  4. Universal nonlinear scattering in ultra-high Q whispering gallery-mode resonators.

    Science.gov (United States)

    Lin, Guoping; Diallo, Souleymane; Dudley, John M; Chembo, Yanne K

    2016-06-27

    Universal nonlinear scattering processes such as Brillouin, Raman, and Kerr effects are fundamental light-matter interactions of particular theoretical and experimental importance. They originate from the interaction of a laser field with an optical medium at the lattice, molecular, and electronic scale, respectively. These nonlinear effects are generally observed and analyzed separately, because they do not often occur concomitantly. In this article, we report the simultaneous excitation of these three fundamental interactions in mm-size ultra-high Q whispering gallery mode resonators under continuous wave pumping. Universal nonlinear scattering is demonstrated in barium fluoride and strontium fluoride, separately. We further propose a unified theory based on a spatiotemporal formalism for the understanding of this phenomenology.

  5. Low-threshold stimulated Brillouin scattering in high-Q whispering gallery mode tellurite microspheres.

    Science.gov (United States)

    Guo, Changlei; Che, Kaijun; Zhang, Pan; Wu, Jinshu; Huang, Yantang; Xu, Huiying; Cai, Zhiping

    2015-12-14

    We demonstrate the first observation of stimulated Brillouin scattering (SBS) in a high-Q whispering gallery mode tellurite microsphere. Tellurite glass with composition of 70TeO₂-20ZnO-5Na₂O-5La₂O₃ (molar ratio) was prepared in-house using a melt-quenching technique. Moreover, tellurite microspheres with Q in excess of 13 millions at 1550 nm were fabricated by melting tellurite microwires using a CO₂ laser. By pumping the tellurite microspheres with a tunable single frequency laser, SBS is further realized with a threshold as low as 0.58 mW. At last, the beat notes between the pump and the Stokes signals were measured, which indicated the Brillouin frequency shift is at the 8.2 GHz band for our tellurite glass. Our results could propel significant applications utilizing SBS by employing tellurite microspheres.

  6. High Q-factor micro-cavity laser: Fabrication and lasing emission properties

    Energy Technology Data Exchange (ETDEWEB)

    Pham Van Hoi; Ha Xuan Vinh; Chu Thi Thu Ha; Tran Thi Cham [Institute of Materials Science, Vietname Academy of Science and Technology 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Bui Van Thien [Faculty of Natural Science, College of Medicine, Thai Nguyen (Viet Nam); Gruzintsev, A N [Institute of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences (IPMT-RAS) (Russian Federation)], E-mail: hoipv@ims.vast.ac.vn

    2009-09-01

    In this article the fabrication method and lasing emission properties of High-Q micro-cavity lasers based on High-concentration Erbium-doped silica-alumina glasses are presented in detail. The configurations of micro-cavities were spherical and/or modified toroidal forms. The lasing threshold of micro-cavity laser pumped by laser diodes was of hundred micro-watts and Q-factor of cavity had been achieved up-to 10{sup 8} in experiment. The emission power of one whispering-gallery-mode (WGM) lasing from micro-cavity laser was of 0.05-0.5 mW that would be enough for applying in the quantum information and optical sensor techniques. The modified toroidal micro-cavity permits to decrease the polar-mode of WGMs, which help to obtain the single-mode emission from micro-cavity lasers.

  7. Fabrication of high-Q microresonators in dielectric materials using a femtosecond laser: Principle and applications

    Science.gov (United States)

    Wang, Min; Lin, Jin-Tian; Xu, Ying-Xin; Fang, Zhi-Wei; Qiao, Ling-Ling; Liu, Zheng-Ming; Fang, Wei; Cheng, Ya

    2017-07-01

    Femtosecond laser micromachining has been a promising technique for fabricating three-dimensional (3D) micro/nano-structures in various kinds of dielectric materials with unprecedented spatial resolutions as well as flexibility in terms of the geometry and the materials can be processed. This unique capability opens opportunities for fabrication of 3D high-quality (Q) microresonators, which are one of the key elements in modern photonic applications. Here, we review the recent progress in fabrication of high-Q microresonators on glass and crystalline substrates by employing femtosecond laser direct writing. We demonstrate the applications of the fabricated microresonators in generating low-threshold lasers, high-sensitivity chemical sensing and nonlinear optical wavelength conversion.

  8. Reproducibility of High-Q SRF Cavities by High Temperature Heat Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Dhakal, Pashupati [JLAB; Ciovati, Gianluigi [JLAB; Kneisel, Peter [JLAB; Myneni, Ganapati Rao [JLAB

    2014-07-01

    Recent work on high-temperature (> 600 °C) heat treatment of ingot Nb cavities in a customized vacuum furnace for several hours showed the possibility of achieving Q0-values of up to ~5×1010 at 2.0 K, 1.5 GHz and accelerating gradients of ~20 MV/m. This contribution presents results on further studies of the heat treatment process to produce cavities with high Q0 values for continuous-wave accelerator application. Single-cell cavities of different Nb purity have been processed through few cycles of heat-treatments and chemical etching. Measurements of Q0 as a function of temperature at low RF field and of Q0 as a function of the RF field at or below 2.0 K have been made after each treatment. Measurements by TOF-SIMS of the impurities depth profiles were made on samples heat treated with the cavities.

  9. Vertical integration of high-Q silicon nitride microresonators into silicon-on-insulator platform.

    Science.gov (United States)

    Li, Qing; Eftekhar, Ali A; Sodagar, Majid; Xia, Zhixuan; Atabaki, Amir H; Adibi, Ali

    2013-07-29

    We demonstrate a vertical integration of high-Q silicon nitride microresonators into the silicon-on-insulator platform for applications at the telecommunication wavelengths. Low-loss silicon nitride films with a thickness of 400 nm are successfully grown, enabling compact silicon nitride microresonators with ultra-high intrinsic Qs (~ 6 × 10(6) for 60 μm radius and ~ 2 × 10(7) for 240 μm radius). The coupling between the silicon nitride microresonator and the underneath silicon waveguide is based on evanescent coupling with silicon dioxide as buffer. Selective coupling to a desired radial mode of the silicon nitride microresonator is also achievable using a pulley coupling scheme. In this work, a 60-μm-radius silicon nitride microresonator has been successfully integrated into the silicon-on-insulator platform, showing a single-mode operation with an intrinsic Q of 2 × 10(6).

  10. Coupling Light from a High-Q Microsphere Resonator Using a UV-induced Surface Grating

    Science.gov (United States)

    Ilchenko, V. S.; Starodubov, D. S.; Gorodetsky, M. L.; Maleki, L.; Feinberg, J.

    2000-01-01

    High-Q microspheres with whispering-gallery modes have very narrow resonances that can be used for fiber-optic filters, ultra-compact narrow-linewidth lasers and optical/microwave oscillators. Whispering-gallery modes were previously excited in microspheres using evanescent optical fields. The necessary phase synchronism was obtained by adjusting the incident angle of input light beam (prism coupler) or adjustment of the waveguide propagation constant (fiber taper coupler). For many applications, however, bulky near-field couplers are undesirable. They compromise the symmetry and generate stray fields. Also, the control of coupling is crucial for the performance of microsphere resonators: in analogy with radio frequency circuits, the loading Q-factor should be less than the intrinsic Q-factor, Q(sub L) less than or equal to Q(sub O). Ideally one should combine a stable coupling element and a resonator into a single microsphere component.

  11. Perspective: Acoustic metamaterials in transition

    KAUST Repository

    Wu, Ying

    2017-12-15

    Acoustic metamaterials derive their novel characteristics from the interaction between acoustic waves with designed structures. Since its inception seventeen years ago, the field has been driven by fundamental geometric and physical principles that guide the structure design rules as well as provide the basis for wave functionalities. Recent examples include resonance-based acoustic metasurfaces that offer flexible control of acoustic wave propagation such as focusing and re-direction; parity-time (PT)-symmetric acoustics that utilizes the general concept of pairing loss and gain to achieve perfect absorption at a single frequency; and topological phononics that can provide one-way edge state propagation. However, such novel functionalities are not without constraints. Metasurface elements rely on resonances to enhance their coupling to the incident wave; hence, its functionality is limited to a narrow frequency band. Topological phononics is the result of the special lattice symmetry that must be fixed at the fabrication stage. Overcoming such constraints naturally forms the basis for further developments. We identify two emergent directions: Integration of acoustic metamaterial elements for achieving broadband characteristics as well as acoustic wave manipulation tasks more complex than the single demonstrative functionality; and active acoustic metamaterials that can adapt to environment as well as to go beyond the constraints on the passive acoustic metamaterials. Examples of a successful recent integration of multi-resonators in achieving broadband sound absorption can be found in optimal sound-absorbing structures, which utilize causality constraint as a design tool in realizing the target-set absorption spectrum with a minimal sample thickness. Active acoustic metamaterials have also demonstrated the capability to tune bandgaps as well as to alter property of resonances in real time through stiffening of the spring constants, in addition to the PT symmetric

  12. Experimental realization of a terahertz all-dielectric metasurface absorber.

    Science.gov (United States)

    Liu, Xinyu; Fan, Kebin; Shadrivov, Ilya V; Padilla, Willie J

    2017-01-09

    Metamaterial absorbers consisting of metal, metal-dielectric, or dielectric materials have been realized across much of the electromagnetic spectrum and have demonstrated novel properties and applications. However, most absorbers utilize metals and thus are limited in applicability due to their low melting point, high Ohmic loss and high thermal conductivity. Other approaches rely on large dielectric structures and / or a supporting dielectric substrate as a loss mechanism, thereby realizing large absorption volumes. Here we present a terahertz (THz) all dielectric metasurface absorber based on hybrid dielectric waveguide resonances. We tune the metasurface geometry in order to overlap electric and magnetic dipole resonances at the same frequency, thus achieving an experimental absorption of 97.5%. A simulated dielectric metasurface achieves a total absorption coefficient enhancement factor of FT=140, with a small absorption volume. Our experimental results are well described by theory and simulations and not limited to the THz range, but may be extended to microwave, infrared and optical frequencies. The concept of an all-dielectric metasurface absorber offers a new route for control of the emission and absorption of electromagnetic radiation from surfaces with potential applications in energy harvesting, imaging, and sensing.

  13. Low frequency piezoresonance defined dynamic control of terahertz wave propagation.

    Science.gov (United States)

    Dutta, Moumita; Betal, Soutik; Peralta, Xomalin G; Bhalla, Amar S; Guo, Ruyan

    2016-11-30

    Phase modulators are one of the key components of many applications in electromagnetic and opto-electric wave propagations. Phase-shifters play an integral role in communications, imaging and in coherent material excitations. In order to realize the terahertz (THz) electromagnetic spectrum as a fully-functional bandwidth, the development of a family of efficient THz phase modulators is needed. Although there have been quite a few attempts to implement THz phase modulators based on quantum-well structures, liquid crystals, or meta-materials, significantly improved sensitivity and dynamic control for phase modulation, as we believe can be enabled by piezoelectric-resonance devices, is yet to be investigated. In this article we provide an experimental demonstration of phase modulation of THz beam by operating a ferroelectric single crystal LiNbO3 film device at the piezo-resonance. The piezo-resonance, excited by an external a.c. electric field, develops a coupling between electromagnetic and lattice-wave and this coupling governs the wave propagation of the incident THz beam by modulating its phase transfer function. We report the understanding developed in this work can facilitate the design and fabrication of a family of resonance-defined highly sensitive and extremely low energy sub-millimeter wave sensors and modulators.

  14. Terahertz Sensor Using Photonic Crystal Cavity and Resonant Tunneling Diodes

    Science.gov (United States)

    Okamoto, Kazuma; Tsuruda, Kazuisao; Diebold, Sebastian; Hisatake, Shintaro; Fujita, Masayuki; Nagatsuma, Tadao

    2017-09-01

    In this paper, we report on a terahertz (THz) sensing system. Compared to previously reported systems, it has increased system sensitivity and reduced size. Both are achieved by using a photonic crystal (PC) cavity as a resonator and compact resonant tunneling diodes (RTDs) as signal source and as detector. The measured quality factor of the PC cavity is higher than 10,000, and its resonant frequency is 318 GHz. To demonstrate the operation of the refractive index sensing system, dielectric tapes of various thicknesses are attached to the PC cavity and the change in the resonator's refractive index is measured. The figure of merit of refractive index sensing using the developed system is one order higher than that of previous studies, which used metallic metamaterial resonators. The frequency of the RTD-based source can be swept from 316 to 321 GHz by varying the RTD direct current voltage. This effect is used to realize a compact frequency tunable signal source. Measurements using a commercial signal source and detector are carried out to verify the accuracy of the data obtained using RTDs as a signal source and as a detector.

  15. Ultrafast terahertz electrodynamics of photonic and electronic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Liang [Iowa State Univ., Ames, IA (United States)

    2015-01-01

    This thesis summarizes my work on using ultrafast laser pulses to study Terahertz (THz) electrodynamics of photonic and electronic nanostructures and microstructures. Ultrafast timeresolved (optical, NIR, MIR, THz) pump-probe spectroscopy setup has been successfully built, which enables me to perform a series of relevant experiments. Firstly, a novel high e ciency and compact THz wave emitter based on split-ring-resonators has been developed and characterized. The emitter can be pumped at any wavelength by tailoring the magnetic resonance and could generate gapless THz waves covering the entire THz band. Secondly, two kinds of new photonic structures for THz wave manipulation have been successfully designed and characterized. One is based on the 1D and 2D photo-imprinted di ractive elements. The other is based on the photoexcited double-split-ring-resonator metamaterials. Both structures are exible and can modulate THz waves with large tunability. Thirdly, the dark excitons in semiconducting singlewalled carbon nanotubes are studied by optical pump and THz probe spectroscopy, which provides the rst insights into the THz responses of nonequilibrium excitonic correlations and dynamics from the dark ground states in carbon nanotubes. Next, several on-going projects are brie y presented such as the study of ultrafast THz dynamics of Dirac fermions in topological insulator Bi2Se3 with Mid-infrared excitation. Finally, the thesis ends with a summary of the completed experiments and an outlook of the future plan.

  16. Metamaterial Apertures for Computational Imaging

    Science.gov (United States)

    Hunt, John; Driscoll, Tom; Mrozack, Alex; Lipworth, Guy; Reynolds, Matthew; Brady, David; Smith, David R.

    2013-01-01

    By leveraging metamaterials and compressive imaging, a low-profile aperture capable of microwave imaging without lenses, moving parts, or phase shifters is demonstrated. This designer aperture allows image compression to be performed on the physical hardware layer rather than in the postprocessing stage, thus averting the detector, storage, and transmission costs associated with full diffraction-limited sampling of a scene. A guided-wave metamaterial aperture is used to perform compressive image reconstruction at 10 frames per second of two-dimensional (range and angle) sparse still and video scenes at K-band (18 to 26 gigahertz) frequencies, using frequency diversity to avoid mechanical scanning. Image acquisition is accomplished with a 40:1 compression ratio.

  17. Terahertz applications: trends and challenges

    Science.gov (United States)

    Robin, Thierry; Bouye, Clementine; Cochard, Jacques

    2014-03-01

    The objective of our work [1] was to determine the opportunities and challenges for Terahertz application development for the next years with a focus on systems: for homeland security and for Non Destructive Testing (NDT). Terahertz radiation has unique abilities and has been the subject of extensive research for many years. Proven concepts have emerged for numerous applications including Industrial NDT, Security, Health, Telecommunications, etc. Nevertheless, there has been no widely deployed application and Businesses based on THz technologies are still in their infancy. Some technological, market and industrial barriers are still to be broken. We summarize the final analysis and data: study of the technology trends and major bottlenecks per application segment, main challenges to be addressed in the next years, key opportunities for THz technologies based on market needs and requirements.

  18. Extrinsic electromagnetic chirality in all-photodesigned one-dimensional THz metamaterials

    CERN Document Server

    Rizza, Carlo; Brambilla, Massimo; Prati, Franco; Ciattoni, Alessandro

    2016-01-01

    We suggest that all-photodesigned metamaterials, sub-wavelength custom patterns of photo-excited carriers on a semiconductor, can display an exotic extrinsic electromagnetic chirality in terahertz (THz) frequency range. We consider a photo-induced pattern exhibiting 1D geometrical chirality, i.e. its mirror image can not be superposed onto itself by translations without rotations and, in the long wavelength limit, we evaluate its bianisotropic response. The photo-induced extrinsic chirality turns out to be fully reconfigurable by recasting the optical illumination which supports the photo-excited carriers. The all-photodesigning technique represents a feasible, easy and powerful method for achieving effective matter functionalization and, combined with the chiral asymmetry, it could be the platform for a new generation of reconfigurable devices for THz wave polarization manipulation.

  19. Review in terahertz spectral analysis

    OpenAIRE

    El Haddad, Josette; Bousquet, Bruno; Canioni, Lionel; Mounaix, Patrick

    2013-01-01

    International audience; Nowadays terahertz spectroscopy is a well-established technique and recent progresses in technology demonstrated that this new technique is useful for both fundamental research and industrial applications. Varieties of applications such as imaging, non destructive testing, quality control are about to be transferred to industry supported by permanent improvements from basic research. Since chemometrics is today routinely applied to IR spectroscopy, we discuss in this p...

  20. Regulatory effects of terahertz waves

    OpenAIRE

    Vyacheslav F. Kirichuk; Alexey N. Ivanov

    2013-01-01

    There are modern data about biological effects of terahertz (THz) waves in this article. Items of interaction of THz waves with bio objects of different organization level. A complex of the data indicates that the realization of a THz wave effect in biosystems is possible at molecular, cellular, tissular, organ and system levels of regulation. There are data about changes in nervous and humoral regulation of an organism and metabolic effects of THz waves.

  1. Ultrabroadband terahertz conductivity of Si nanocrystal films

    DEFF Research Database (Denmark)

    Cooke, D. G.; Meldrum, A.; Jepsen, P. Uhd

    2012-01-01

    The terahertz conductivity of silicon nanoparticles embedded in glass with varying density is studied with ultra-broadband terahertz spectroscopy on picosecond time scales following fs optical excitation. The transition from relatively isolated charge carriers to densities which allow inter...... the applicability of this simple model to the conductivity of nanoparticle ensembles over the entire THz spectral window....

  2. Modeling terahertz heating effects on water

    DEFF Research Database (Denmark)

    Kristensen, Torben T.L.; Withayachumnankul, Withawat; Jepsen, Peter Uhd

    2010-01-01

    We apply Kirchhoff’s heat equation to model the influence of a CW terahertz beam on a sample of water, which is assumed to be static. We develop a generalized model, which easily can be applied to other liquids and solids by changing the material constants. If the terahertz light source is focused...

  3. Design of a programmable active acoustics metamaterial

    Science.gov (United States)

    Smoker, Jason J.

    Metamaterials are artificial materials engineered to provide properties which may not be readily available in nature. The development of such class of materials constitutes a new area of research that has grown significantly over the past decade. Acoustic metamaterials, specifically, are even more novel than their electromagnetic counterparts arising only in the latter half of the decade. Acoustic metamaterials provide a new tool in controlling the propagation of pressure waves. However, physical design and frequency tuning, is still a large obstacle when creating a new acoustic metamaterial. This dissertation describes active and programmable design for acoustic metamaterials which allows the same basic physical design principles to be used for a variety of application. With cloaking technology being of a great interest to the US Navy, the proposed design approach would enable the development of a metamaterial with spatially changing effective parameters while retaining a uniform physical design features. The effective parameters would be controlled by tuning smart actuators embedded inside the metamaterial structure. Since this design is based on dynamic effective parameters that can be electrically controlled, material property ranges of several orders of magnitude could potentially be achieved without changing any physical parameters. With such unique capabilities, physically realizable acoustic cloaks can be achieved and objects treated with these active metamaterials can become acoustically invisible.

  4. Coaxial plasmonic metamaterials for visible light

    NARCIS (Netherlands)

    van de Haar, M.A.

    2016-01-01

    Optical metamaterials are materials built from sub-wavelength building blocks, and can be designed to have effective optical properties that are not found in natural materials. A much-studied class of metamaterials uses small noble-metal resonant structures as building blocks, which have a

  5. Circuit QED with hybrid metamaterial transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Ruloff, Stefan; Taketani, Bruno; Wilhelm, Frank [Theoretical Physics, Universitaet des Saarlandes, Saarbruecken (Germany)

    2016-07-01

    We're working on the theory of metamaterials providing some interesting results. The negative refraction index causes an opposite orientation of the wave vector k and the Poynting vector S of the travelling waves. Hence the metamaterial has a falling dispersion relation ∂ω(k)/∂k < 0 implying that low frequencies correspond to short wavelengths. Metamaterials are simulated by left-handed transmission lines consisting of discrete arrays of series capacitors and parallel inductors to ground. Unusual physics arises when right-and left-handed transmission lines are coupled forming a hybrid metamaterial transmission line. E.g. if a qubit is placed in front of a hybrid metamaterial transmission line terminated in an open circuit, the spontaneous emission rate is weakened or unaffected depending on the transition frequency of the qubit. Some other research interests are the general analysis of metamaterial cavities and the mode structure of hybrid metamaterial cavities for QND readout of multi-qubit operators. Especially the precise answer to the question about the definition of the mode volume of a metamaterial cavity is one of our primary goals.

  6. The left hand of electromagnetism : metamaterials

    OpenAIRE

    Alıcı, Kamil Boratay

    2010-01-01

    Ankara : The Department of Physics and the Institute of Engineering and Science of Bilkent University, 2010. Thesis (Ph. D.) -- Bilkent University, 2010. Includes bibliographical references leaves 160-172. Metamaterials are artificial periodic structures whose electromagnetic response is solely dependent on the constituting unit cells. In the present thesis, we studied unit cell characteristics of metamaterials that has negative permeability and permittivity. We investigate...

  7. Metamaterials for Miniaturization of Optical Components

    Science.gov (United States)

    2014-09-24

    work for reported period is related to two major areas: (i) Neoclassical theory of electromagnetic interactions with special features at nanoscale...relativistic and spinorial aspects of our neoclassical electromagnetic theory . Metamaterials, fundamentals of electromagnetic theory , dissipation, magnetic...the our neoclassical electromagnetic theory for elementary charges including atomic nanoscales relevant to metamaterials and miniaturization of

  8. Various uses for optical metamaterials

    Science.gov (United States)

    Barbosa, Jose G.

    2015-05-01

    Optical metamaterials promise aberration free and better than diffraction limited performance for imaging systems through constructed materials made to regulate the interaction with electromagnetic waves. Optical metamaterials have the potential to miniaturize the optical bench and obtain diffraction-limited performance with a single device. The reduction of size, weight, and complexity of optical systems while maintaining performance is desired. In unmanned aircrafts, buoy systems, 360 degree imaging systems, and optronic or traditional periscope systems the lenses constitute a considerable percentage of the weight and volume. Another characteristic that is desired is optical cross section reduction for both visible and infrared bands. Optical cloaking using metamaterials has the potential to make objects indiscernible from its environment by masking objects signature. Other characteristics that are desired are materials that are perfect light absorbers for stray light baffles, detectors, or solar energy harvesting, nonlinear frequency conversion for photonics devices, and lenses or head window coatings to achieve specific properties. These topics are discussed in this paper.

  9. Acoustic metamaterials with synergetic coupling

    Science.gov (United States)

    Ma, Fuyin; Huang, Meng; Wu, Jiu Hui

    2017-12-01

    In this paper, we propose a general design concept for acoustic metamaterials that introduces a ubiquitous synergetic behavior into the design procedure, in which the structure of the design is driven by its functional requirements. Since the physical properties of the widely used, resonant-type metamaterials are mainly determined by the eigenmodes of the structure, we first introduce the design concept through the modal displacement distributions on two typical plate-type structures. Next, by employing broadband sound attenuations that involve both the insulation and absorption as the typical targets, two synergetic coupling behaviors are systematically revealed among the dense resonant modes and multi-cell. Furthermore, through plate-type multiple-cell structures assembled from nine oscillators, the design is shown to realize strong broadband attenuations with either the average sound transmission loss (STL) below 2000 Hz higher than 40 dB or the absorption approximately 0.99 in the range of 400-700 Hz wherein the average absorption below 800 Hz remains higher than 0.8. Finally, two multi-cell plate-type samples are fabricated and then used experimentally to measure the STLs in support of the proposed synergetic coupling design method. Both the computational and experimental results demonstrate that the proposed synergetic design concept could effectively initiate a design for metamaterials that offer a new degree of freedom for broadband sound attenuations.

  10. Terahertz semiconductor-heterostructure laser.

    Science.gov (United States)

    Köhler, Rüdeger; Tredicucci, Alessandro; Beltram, Fabio; Beere, Harvey E; Linfield, Edmund H; Davies, A Giles; Ritchie, David A; Iotti, Rita C; Rossi, Fausto

    2002-05-09

    Semiconductor devices have become indispensable for generating electromagnetic radiation in everyday applications. Visible and infrared diode lasers are at the core of information technology, and at the other end of the spectrum, microwave and radio-frequency emitters enable wireless communications. But the terahertz region (1-10 THz; 1 THz = 10(12) Hz) between these ranges has remained largely underdeveloped, despite the identification of various possible applications--for example, chemical detection, astronomy and medical imaging. Progress in this area has been hampered by the lack of compact, low-consumption, solid-state terahertz sources. Here we report a monolithic terahertz injection laser that is based on interminiband transitions in the conduction band of a semiconductor (GaAs/AlGaAs) heterostructure. The prototype demonstrated emits a single mode at 4.4 THz, and already shows high output powers of more than 2 mW with low threshold current densities of about a few hundred A cm(-2) up to 50 K. These results are very promising for extending the present laser concept to continuous-wave and high-temperature operation, which would lead to implementation in practical photonic systems.

  11. Nanoscale Laser Terahertz Emission Microscopy

    DEFF Research Database (Denmark)

    Klarskov, Pernille; Kim, Hyewon; Colvin, Vicki L.

    2017-01-01

    Laser terahertz emission microscopy (LTEM) has become a powerful tool for studying ultrafast dynamics and local fields in many different types of materials. This technique, which relies on acceleration of charge carriers in a material upon femtosecond excitation, can provide insight into the phys......Laser terahertz emission microscopy (LTEM) has become a powerful tool for studying ultrafast dynamics and local fields in many different types of materials. This technique, which relies on acceleration of charge carriers in a material upon femtosecond excitation, can provide insight...... into the physics of charge transport, built-in fields, grain boundaries or surface states. We describe a new implementation of LTEM with a spatial resolution in the nanoscale regime based on a scattering-type near-field tip-based approach. We observe a spectral reshaping of the signal compared to conventional LTEM......-size-limited spatial resolution of ∼20 nm by imaging a gold nanorod using terahertz emission from the underlying substrate. This work enables for the first time the possibility of performing LTEM measurements on individual nanostructures....

  12. Broadband electromagnetic cloaking with smart metamaterials

    Science.gov (United States)

    Shin, Dongheok; Urzhumov, Yaroslav; Jung, Youngjean; Kang, Gumin; Baek, Seunghwa; Choi, Minjung; Park, Haesung; Kim, Kyoungsik; Smith, David R.

    2012-11-01

    The ability to render objects invisible with a cloak that fits all objects and sizes is a long-standing goal for optical devices. Invisibility devices demonstrated so far typically comprise a rigid structure wrapped around an object to which it is fitted. Here we demonstrate smart metamaterial cloaking, wherein the metamaterial device not only transforms electromagnetic fields to make an object invisible, but also acquires its properties automatically from its own elastic deformation. The demonstrated device is a ground-plane microwave cloak composed of an elastic metamaterial with a broad operational band (10-12 GHz) and nearly lossless electromagnetic properties. The metamaterial is uniform, or perfectly periodic, in its undeformed state and acquires the necessary gradient-index profile, mimicking a quasi-conformal transformation, naturally from a boundary load. This easy-to-fabricate hybrid elasto-electromagnetic metamaterial opens the door to implementations of a variety of transformation optics devices based on quasi-conformal maps.

  13. Broadband electromagnetic cloaking with smart metamaterials.

    Science.gov (United States)

    Shin, Dongheok; Urzhumov, Yaroslav; Jung, Youngjean; Kang, Gumin; Baek, Seunghwa; Choi, Minjung; Park, Haesung; Kim, Kyoungsik; Smith, David R

    2012-01-01

    The ability to render objects invisible with a cloak that fits all objects and sizes is a long-standing goal for optical devices. Invisibility devices demonstrated so far typically comprise a rigid structure wrapped around an object to which it is fitted. Here we demonstrate smart metamaterial cloaking, wherein the metamaterial device not only transforms electromagnetic fields to make an object invisible, but also acquires its properties automatically from its own elastic deformation. The demonstrated device is a ground-plane microwave cloak composed of an elastic metamaterial with a broad operational band (10-12 GHz) and nearly lossless electromagnetic properties. The metamaterial is uniform, or perfectly periodic, in its undeformed state and acquires the necessary gradient-index profile, mimicking a quasi-conformal transformation, naturally from a boundary load. This easy-to-fabricate hybrid elasto-electromagnetic metamaterial opens the door to implementations of a variety of transformation optics devices based on quasi-conformal maps.

  14. Water based fluidic radio frequency metamaterials

    Science.gov (United States)

    Cai, Xiaobing; Zhao, Shaolin; Hu, Mingjun; Xiao, Junfeng; Zhang, Naibo; Yang, Jun

    2017-11-01

    Electromagnetic metamaterials offer great flexibility for wave manipulation and enable exceptional functionality design, ranging from negative refraction, anomalous reflection, super-resolution imaging, transformation optics to cloaking, etc. However, demonstration of metamaterials with unprecedented functionalities is still challenging and costly due to the structural complexity or special material properties. Here, we demonstrate for the first time the versatile fluidic radio frequency metamaterials with negative refraction using a water-embedded and metal-coated 3D architecture. Effective medium analysis confirms that metallic frames create an evanescent environment while simultaneously water cylinders produce negative permeability under Mie resonance. The water-metal coupled 3D architectures and the accessory devices for measurement are fabricated by 3D printing with post electroless deposition. Our study also reveals the great potential of fluidic metamaterials and versatility of the 3D printing process in rapid prototyping of customized metamaterials.

  15. Optical properties of nanowire metamaterials with gain

    DEFF Research Database (Denmark)

    Isidio de Lima, Joaquim Junior; Adam, Jost; Rego, Davi

    2016-01-01

    The transmittance, reflectance and absorption of a nanowire metamaterial with optical gain are numerically simulated and investigated. It is assumed that the metamaterial is represented by aligned silver nanowires embedded into a semiconductor matrix, made of either silicon or gallium phosphide....... The gain in the matrix is modeled by adding a negative imaginary part to the dielectric function of the semiconductor. It is found that the optical coefficients of the metamaterial depend on the gain magnitude in a non-trivial way: they can both increase and decrease with gain depending on the lattice...... constant of the metamaterial. This peculiar behavior is explained by the field redistribution between the lossy metal nanowires and the amplifying matrix material. These findings are significant for a proper design of nanowire metamaterials with low optical losses for diverse applications....

  16. Nonlinear electromagnetic response of superconducting quantum metamaterials

    Science.gov (United States)

    Kawabata, Shiro

    Metamaterials are artificial electromagnetic materials consisting of artificial atoms, that is, artificial structures whose sizes are small compared to the wavelength of respective electromagnetic (EM) wave. The effective permittivity and permeability of metamaterials can be controlled at will by changing shapes and arrangements of the artificial atoms. The concept of metamaterial is quite useful for fabricating novel optical devices such as cloaking devices. Recently, quantum metamaterial (QMM), which utilizes superconducting qubits as artificial atoms, has been theoretically proposed and its prototypes have been realized experimentally. Unlike conventional metamaterials composed of classical elements, QMMs are expected to show several unique EM responses originating from quantum superposition and entanglement of qubits. In this talk, we will present our recent theoretical studies on the nonlinear EM response of a QMM based on superconducting qubit arrays. Especially, we will discuss on a peculiar lasing phenomena and the formation of a superconducting-vortex state in such systems.

  17. Tunable beam steering enabled by graphene metamaterials.

    Science.gov (United States)

    Orazbayev, B; Beruete, M; Khromova, I

    2016-04-18

    We demonstrate tunable mid-infrared (MIR) beam steering devices based on multilayer graphene-dielectric metamaterials. The effective refractive index of such metamaterials can be manipulated by changing the chemical potential of each graphene layer. This can arbitrarily tailor the spatial distribution of the phase of the transmitted beam, providing mechanisms for active beam steering. Three different beam steerer (BS) designs are discussed: a graded-index (GRIN) graphene-based metamaterial block, an array of metallic waveguides filled with graphene-dielectric metamaterial and an array of planar waveguides created in a graphene-dielectric metamaterial block with a specific spatial profile of graphene sheets doping. The performances of the BSs are numerically analyzed, showing the tunability of the proposed designs for a wide range of output angles (up to approximately 70°). The proposed graphene-based tunable beam steering can be used in tunable transmitter/receiver modules for infrared imaging and sensing.

  18. Multimode, Aperiodic Terahertz Surface-Emitting Laser Resonators

    Directory of Open Access Journals (Sweden)

    Simone Biasco

    2016-05-01

    Full Text Available Quasi-crystal structures are conventionally built following deterministic generation rules although they do not present a full spatial periodicity. If used as laser resonators, they open up intriguing design possibilities that are simply not possible in conventional periodic photonic crystals: the distinction between symmetric (vertically radiative but low quality factor Q and anti-symmetric (non-radiative, high Q modes is indeed here fully overcome, offering a concrete perspective of highly efficient vertical emitting resonators. We here exploit electrically pumped terahertz quantum cascade heterostructures to devise two-dimensional seven-fold quasi-crystal resonators, exploiting rotational order or irregularly distributed defects. By lithographically tuning the lattice quasi-periodicity and/or the hole radius of the imprinted patterns, efficient multimode surface emission with a rich sequence of spectral lines distributed over a 2.9–3.4 THz bandwidth was reached. We demonstrated multicolor emission with 67 mW of peak optical power, slope efficiencies up to ≈70 mW/A, 0.14% wall plug efficiencies and beam profile results of the rich quasi-crystal Fourier spectrum that, in the case of larger rotational order, can reach very low divergence.

  19. Sub-picosecond optical switching with a negative index metamaterial

    Energy Technology Data Exchange (ETDEWEB)

    Dani, Keshav M [Los Alamos National Laboratory; Upadhya, Prashant C [Los Alamos National Laboratory; Zahyum, Ku [CHTM-UNM

    2009-01-01

    Development of all-optical signal processing, eliminating the performance and cost penalties of optical-electrical-optical conversion, is important for continu,ing advances in Terabits/sec (Tb/s) communications.' Optical nonlinearities are generally weak, traditionally requiring long-path, large-area devicesl,2 or very high-Q, narrow-band resonator structures.3 Optical metamaterials offer unique capabilities for optical-optical interactions. Here we report 600 femtosecond (fs) all-optical modulation using a fIShnet (2D-perforated metallamorphous-Si (a-Si)/metal film stack) negative-index meta material with a structurally tunable broad-band response near 1.2 {micro}m. Over 20% modulation (experimentally limited) is achieved in a path length of only 116 nm by photo-excitation of carriers in the a-Si layer. This has the potential for Tb/s aU-optical communication and will lead to other novel, compact, tunable sub-picosecond (ps) photonic devices.

  20. Multiple-band light absorber via combining the fundamental mode and multiple splitting modes of the 3-order response of metamaterial resonator

    Science.gov (United States)

    Wang, Ben-Xin; Xie, Qin; Dong, Guangxi; Huang, Wei-Qing

    2017-12-01

    We present a rather simple metamaterial design consisted of only a rectangle-shape patch structure with a very small air strip on it to realize triple-band absorption at terahertz frequency. Results prove that three narrow-band absorption peaks are obtained at frequencies of 0.94 THz, 2.44 THz, and 2.85 THz, and the average absorption rates of the three peaks are 97.00%. The resonance at 0.94 THz is attributed to the fundamental mode (or 1-order) response of the metamaterial, while the last two modes are due to the two splitting modes of the 3-order response. The parameter changes of the small air strip in the rectangle-shape patch structure have large influence on the absorption performance of the metamaterial, in particular of the last two modes. Importantly, quad-band absorption can be obtained by introducing one more air strip in the rectangle-shape patch structure. It is found that the first resonance peak is derived from the 1-order response, whereas the last three modes stem from the three splitting modes of the 3-order response of the metamaterial. The combination of the 1-order resonance and multiple splitting modes of the 3-order response provides new design method to realize multiple-band light absorbers.

  1. Versatile tissue lasers based on high-Q Fabry-Pérot microcavities.

    Science.gov (United States)

    Chen, Yu-Cheng; Chen, Qiushu; Zhang, Tingting; Wang, Wenjie; Fan, Xudong

    2017-01-31

    Biolasers are an emerging technology for next generation biochemical detection and clinical applications. Progress has recently been made to achieve lasing from biomolecules and single living cells. Tissues, which consist of cells embedded in an extracellular matrix, mimic more closely the actual complex biological environment in a living body and therefore are of more practical significance. Here, we developed a highly versatile tissue laser platform, in which tissues stained with fluorophores are sandwiched in a high-Q Fabry-Pérot microcavity. Distinct lasing emissions from muscle and adipose tissues stained respectively with fluorescein isothiocyanate (FITC) and boron-dipyrromethene (BODIPY), and hybrid muscle/adipose tissue with dual staining were achieved with a threshold of only ∼10 μJ mm-2. Additionally, we investigated how the tissue structure/geometry, tissue thickness, and staining dye concentration affect the tissue laser. Lasing emission from FITC conjugates (FITC-phalloidin) that specifically target F-actin in muscle tissues was also realized. It is further found that, despite the large fluorescence spectral overlap between FITC and BODIPY in tissues, their lasing emissions could be clearly distinguished and controlled due to their narrow lasing bands and different lasing thresholds, thus enabling highly multiplexed detection. Our tissue laser platform can be broadly applicable to various types of tissues/diseases. It provides a new tool for a wide range of biological and biomedical applications, such as diagnostics/screening of tissues and identification/monitoring of biological transformations in tissue engineering.

  2. A broadband reflective filter for applying dc biases to high-Q superconducting microwave cavities

    Science.gov (United States)

    Hao, Yu; Rouxinol, Francisco; Lahaye, Matt

    2015-03-01

    The integration of dc-bias circuitry into low-loss microwave cavities is an important technical issue for topics in many fields that include research with qubit- and cavity-coupled mechanical system, circuit QED and quantum dynamics of nonlinear systems. The applied potentials or currents serve a variety of functions such as maintaining the operating state of device or establishing tunable electrostatic interactions between devices (for example, in order to couple a nanomechanical resonator to a superconducting qubit to generate and detect quantum states of a mechanical resonator). Here we report a bias-circuit design that utilizes a broadband reflective filter to connect to a high-Q superconducting coplanar waveguide (CPW) cavity. Our design allows us to apply dc-voltages to the center trace of CPW, with negligible changes in loaded quality factors of the fundamental mode. Simulations and measurements of the filter demonstrate insertion loss greater than 20 dB in the range of 3 to 10 GHz. Transmission measurements of the voltage-biased CPW show that loaded quality factors exceeding 105 can be achieved for dc-voltages as high as V = +/- 20V for the cavity operated in the single photon regime. National Science Foundation under Grant No. DMR-1056423 and Grant No. DMR-1312421.

  3. Development of Ultra High Gradient and High Q{sub 0} Superconducting Radio Frequency Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Rongli [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Clemens, William A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Follkie, James E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Harris, Teena M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kushnick, Peter W. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Machie, Danny [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Martin, Robert E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Palczewski, Ari D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Perry, Era A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Slack, Gary L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Williams, R. S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Adolphsen, C. [SLAC, Menlo Park, California, (United States); Li, Z. [SLAC, Menlo Park, California, (United States); Hao, J. K. [Peking University, Beijing (China); Li, Y. M. [Peking University, Beijing (China); Liu, K. X. [Peking University, Beijing (China)

    2013-06-01

    We report on the recent progress at Jefferson Lab in developing ultra high gradient and high Q{sub 0} superconducting radio frequency (SRF) cavities for future SRF based machines. A new 1300 MHz 9-cell prototype cavity is being fabricated. This cavity has an optimized shape in terms of the ratio of the peak surface field (both magnetic and electric) to the acceleration gradient, hence the name low surface field (LSF) shape. The goal of the effort is to demonstrate an acceleration gradient of 50 MV/m with Q{sub 0} of 10{sup 10} at 2 K in a 9-cell SRF cavity. Fine-grain niobium material is used. Conventional forming, machining and electron beam welding method are used for cavity fabrication. New techniques are adopted to ensure repeatable, accurate and inexpensive fabrication of components and the full assembly. The completed cavity is to be first mechanically polished to a mirror-finish, a newly acquired in-house capability at JLab, followed by the proven ILC-style processing recipe established already at JLab. In parallel, new single-cell cavities made from large-grain niobium material are made to further advance the cavity treatment and processing procedures, aiming for the demonstration of an acceleration gradient of 50 MV/m with Q{sub 0} of 2-10{sup 10} at 2K.

  4. Design of high Q-factor metallic nanocavities using plasmonic bandgaps.

    Science.gov (United States)

    Ee, Ho-Seok; Park, Hong-Gyu; Kim, Sun-Kyung

    2016-02-10

    The surface plasmon polariton modes often excited in metallic nanocavities enable the miniaturization of photonic devices, even beyond the diffraction limit, yet their severe optical losses deteriorate device performance. This study proposes a design of metallic nanorod cavities coupled to plasmonic crystals with the aim of reducing the radiation loss of surface plasmon modes. Periodic Ag disks placed on an insulator-metal substrate open a substantial amount of plasmonic bandgaps (e.g., Δλ=290  nm at λ=1550  nm) by modifying their diameter and thickness. When an Ag nanorod with a length of ∼400  nm is surrounded by the periodic Ag disks, its Q-factor increases up to 127, yielding a 16-fold enhancement compared with a bare Ag nanorod, while its mode volume can be as small as 0.03(λ/2n)³. Ag nanorods with gradually increasing lengths exhibit high Q-factor plasmonic modes that are tunable within the plasmonic bandgap. These numerical studies on low-radiation-loss plasmonic modes excited in metallic nanocavities will promote the development of ultrasmall plasmonic devices.

  5. Mid-Infrared ultra-high-Q resonators based on fluoride crystalline materials

    CERN Document Server

    Lecaplain, C; Gorodetsky, M L; Kippenberg, T J

    2016-01-01

    Decades ago, the losses of glasses in the near infrared (near-IR) were investigated in views of developments for optical telecommunications. Today, properties in the mid-infrared (mid-IR) are of interest for molecular spectroscopy applications. In particular, high-sensitivity spectroscopic techniques based on high-finesse mid-IR cavities hold high promise for medical applications. Due to exceptional purity and low losses, whispering gallery mode microresonators based on polished alkaline earth metal fluoride crystals (i.e the $\\mathrm{XF_2}$ family, where X $=$ Ca, Mg, Ba, Sr,...) have attained ultra-high quality (Q) factor resonances (Q$>$10$^{8}$) in the near-IR and visible spectral ranges. Here we report for the first time ultra-high Q factors in the mid-IR using crystalline microresonators. Using an uncoated chalcogenide (ChG) tapered fiber, light from a continuous wave quantum cascade laser (QCL) is efficiently coupled to several crystalline microresonators at 4.4 $\\mu$m wavelength. We measure the optica...

  6. Ultra-high-frequency microwave response from flexible transparent Au electromagnetic metamaterial nanopatterned antenna.

    Science.gov (United States)

    Liu, Dingxin; Niu, Jiebin; Zhu, Haolin; Zhang, Jianyong

    2018-02-09

    Flexible transparent materials are a hot spot in current research but also a key technical difficulty in industry. They are playing an increasingly important role in flexible transparent display applications such as organic light-emitting diodes, transparent electrodes, and so on. On the other hand, the present research on nanopatterned antennas is mainly concentrated on the optical frequency but rarely on the microwave (such as 3G, 4G, and 5G) and terahertz frequency band communications, where nanopatterned antennas can have many novel applications. To the authors' knowledge, this is the first paper that presents a method for preparing a flexible transparent Au electromagnetic metamaterial nanopatterned antenna. We study its free-space performance at ultra-high frequency and its application in electronic products such as smartphones, tablets, personal computers, and wearable devices (such as smart watches) which have the function of mobile communication. The experimental results showed that the transparency of the antenna designed and fabricated in this work can be as high as 94%, and its efficiency can reach 74.5%-91.9% of antennas commonly seen at present in academia and industry. By adjusting the capacitive and inductive reactance of the nanopatterned antenna's matching circuit, combined with its measured efficiency and 3D electromagnetic simulation results, we speculate on the mechanism of the Au electromagnetic metamaterial nanopatterned antenna with good performance.

  7. Ultra-high-frequency microwave response from flexible transparent Au electromagnetic metamaterial nanopatterned antenna

    Science.gov (United States)

    Liu, Dingxin; Niu, Jiebin; Zhu, Haolin; Zhang, Jianyong

    2018-02-01

    Flexible transparent materials are a hot spot in current research but also a key technical difficulty in industry. They are playing an increasingly important role in flexible transparent display applications such as organic light-emitting diodes, transparent electrodes, and so on. On the other hand, the present research on nanopatterned antennas is mainly concentrated on the optical frequency but rarely on the microwave (such as 3G, 4G, and 5G) and terahertz frequency band communications, where nanopatterned antennas can have many novel applications. To the authors’ knowledge, this is the first paper that presents a method for preparing a flexible transparent Au electromagnetic metamaterial nanopatterned antenna. We study its free-space performance at ultra-high frequency and its application in electronic products such as smartphones, tablets, personal computers, and wearable devices (such as smart watches) which have the function of mobile communication. The experimental results showed that the transparency of the antenna designed and fabricated in this work can be as high as 94%, and its efficiency can reach 74.5%–91.9% of antennas commonly seen at present in academia and industry. By adjusting the capacitive and inductive reactance of the nanopatterned antenna’s matching circuit, combined with its measured efficiency and 3D electromagnetic simulation results, we speculate on the mechanism of the Au electromagnetic metamaterial nanopatterned antenna with good performance.

  8. An Ultrafast Switchable Terahertz Polarization Modulator Based on III-V Semiconductor Nanowires.

    Science.gov (United States)

    Baig, Sarwat A; Boland, Jessica L; Damry, Djamshid A; Tan, H Hoe; Jagadish, Chennupati; Joyce, Hannah J; Johnston, Michael B

    2017-04-12

    Progress in the terahertz (THz) region of the electromagnetic spectrum is undergoing major advances, with advanced THz sources and detectors being developed at a rapid pace. Yet, ultrafast THz communication is still to be realized, owing to the lack of practical and effective THz modulators. Here, we present a novel ultrafast active THz polarization modulator based on GaAs semiconductor nanowires arranged in a wire-grid configuration. We utilize an optical pump-terahertz probe spectroscopy system and vary the polarization of the optical pump beam to demonstrate ultrafast THz modulation with a switching time of less than 5 ps and a modulation depth of -8 dB. We achieve an extinction of over 13% and a dynamic range of -9 dB, comparable to microsecond-switchable graphene- and metamaterial-based THz modulators, and surpassing the performance of optically switchable carbon nanotube THz polarizers. We show a broad bandwidth for THz modulation between 0.1 and 4 THz. Thus, this work presents the first THz modulator which combines not only a large modulation depth but also a broad bandwidth and picosecond time resolution for THz intensity and phase modulation, making it an ideal candidate for ultrafast THz communication.

  9. Active Graphene-Based Terahertz Dual-Band Modulator Implemented in the Presence of External Fields

    Science.gov (United States)

    Hu, Xiang; Huang, Qiuping; Zhao, Yi; Cai, Honglei; Lu, Yalin

    2017-07-01

    In this work, we numerically demonstrate a dynamic graphene-based dual-band metamaterial modulator (gDMM) in the presence of an external magnetic field and gate electric field. With the objective of modulating terahertz waves at two separate channels, we utilize the proposed dual-field control method to dynamically modulate the optical conductivity of graphene, and thus the working frequencies of the gDMM. An interpretation for such dependence on the external fields is presented based on a quantum understanding of the energy structure of graphene, and a numerical method based on the finite element method (FEM) is employed to investigate the optical responses of our proposed gDMM. Our results show that, by varying the strength of external fields, one can switch the operation status of the two working channels located at 3.18 THz and 9.04 THz, with modulation depths exceeding 84.4%. Only 30 meV of energy is required for shifting the Fermi level to accomplish the switch, which is extremely low compared with methods in previous works using gate electric control alone. Simultaneous ON/OFF statuses are also realized. Such great tunability and controllability of our proposed gDMM over a wide frequency range may give rise to a new class of dynamic devices for terahertz and microwave applications.

  10. Section 1Tunable broadband terahertz absorbers based on multiple layers of graphene ribbons.

    Science.gov (United States)

    Chen, Dingbo; Yang, Junbo; Zhang, Jingjing; Huang, Jie; Zhang, Zhaojian

    2017-11-20

    A novel metamaterial structure consisting of multiple graphene/dielectric layers and metallic substrate is proposed to achieve the broadband absorption response at terahertz (THz) frequencies. Utilizing the phase modulation effect generated by graphene ribbons, the bright-dark field is formed to suppress the reflection based on interference theory in a wide period. By irregularly stacking four graphene ribbons of varying widths on four dielectric layers with unequal thickness in a period, we merge successive absorption peaks into a broadband absorption spectrum successfully. The absorption decreases with fluctuations as the incident angle increases. The position of the absorption spectrum can be dynamically tuned by a small change in the Fermi level of graphene instead of re-optimizing and re-fabricating the device. In addition, the bandwidth of the absorber can be further improved by means of increasing the graphene/dielectric layers. The structure proposed in this paper has potential applications in tunable terahertz photonic devices such as dynamic broadband filters, modulators and sensors.

  11. Hyperbolic metamaterials: Novel physics and applications

    Science.gov (United States)

    Smolyaninov, Igor I.; Smolyaninova, Vera N.

    2017-10-01

    Hyperbolic metamaterials were originally introduced to overcome the diffraction limit of optical imaging. Soon thereafter it was realized that hyperbolic metamaterials demonstrate a number of novel phenomena resulting from the broadband singular behavior of their density of photonic states. These novel phenomena and applications include super resolution imaging, new stealth technologies, enhanced quantum-electrodynamic effects, thermal hyperconductivity, superconductivity, and interesting gravitation theory analogues. Here we briefly review typical material systems, which exhibit hyperbolic behavior and outline important novel applications of hyperbolic metamaterials. In particular, we will describe recent imaging experiments with plasmonic metamaterials and novel VCSEL geometries, in which the Bragg mirrors may be engineered in such a way that they exhibit hyperbolic metamaterial properties in the long wavelength infrared range, so that they may be used to efficiently remove excess heat from the laser cavity. We will also discuss potential applications of three-dimensional self-assembled photonic hypercrystals, which are based on cobalt ferrofluids in external magnetic field. This system bypasses 3D nanofabrication issues, which typically limit metamaterial applications. Photonic hypercrystals combine the most interesting features of hyperbolic metamaterials and photonic crystals.

  12. Metamaterial Inspired Microstrip Antenna Investigations Using Metascreens

    Directory of Open Access Journals (Sweden)

    Muhammad Tauseef Asim

    2015-01-01

    Full Text Available A dual layer periodically patterned metamaterial inspired antenna on a low cost FR4 substrate is designed, simulated, fabricated, and tested. The eigenmode dispersion simulations are performed indicating the left handed metamaterial characteristics and are tunable with substrate permittivity. The same metamaterial unit cell structure is utilized to fabricate a metascreen. This metascreen is applied below the proposed metamaterial antenna and next used as superstrate above a simple patch to study the effects on impedance bandwidth, gain, and radiation patterns. The experimental results of these antennas are very good and closely match with the simulations. More importantly, the resonance for the proposed metamaterial antenna with metascreen occurs at the left handed (LH eigenfrequency of the metamaterial unit cell structure. The measured −10 dB bandwidths are 14.56% and 22.86% for the metamaterial antenna with single and double metascreens, respectively. The metascreens over the simple patch show adjacent dual band response. The first and second bands have measured −10 dB bandwidths of 9.6% and 16.66%. The simulated peak gain and radiation efficiency are 1.83 dBi and 74%, respectively. The radiation patterns are also very good and could be useful in the UWB wireless applications.

  13. Connection overlap deviation analysis of pentamode metamaterials

    Science.gov (United States)

    Wang, Zhaohong; Liu, Guangshun; Cai, Chengxin; Chu, Yangyang; Li, Yucheng; Xu, Zhuo

    2017-12-01

    The adjacent double-cones of the pentamode metamaterials form a connection overlap for the non-180° angle connection, and the overlap leads to a connection overlap deviation between the actual effective narrow touch diameters d‧ and the defined narrow touch diameters d. The connection overlap deviation increases with the increasing of wide touch diameters D of the double-cones of the pentamode metamaterials with linear outside profile cones. In order to decrease the influence of the connection overlap deviation on the pentamode metamaterials, three types of pentamode metamaterials with small connection overlap (second and third order polynomial outside profile cones structures and the cones stacked by the cylinders-frustums) are proposed and studied in this paper. The connection overlap deviations of pentamode metamaterials with different outside profile cones are analyzed, the phononic band structures are calculated, and the ratio of bulk modulus B to shear modulus G are analyzed for evaluating fluid property. The results show that the pentamode metamaterials proposed by us have smaller connection overlap deviation and more excellent fluid properties than the pentamode metamaterials with linear outside profile cones. The ratio of bulk modulus to shear modulus can be increased by 7.47%–215.92% with the increasing of D from 1 mm to 9.6 mm.

  14. Transforming guided waves with metamaterial waveguide cores

    Science.gov (United States)

    Viaene, S.; Ginis, V.; Danckaert, J.; Tassin, P.

    2016-04-01

    Metamaterials make use of subwavelength building blocks to enhance our control on the propagation of light. To determine the required material properties for a given functionality, i.e., a set of desired light flows inside a metamaterial device, metamaterial designs often rely on a geometrical design tool known as transformation optics. In recent years, applications in integrated photonics motivated several research groups to develop two-dimensional versions of transformation optics capable of routing surface waves along graphene-dielectric and metal-dielectric interfaces. Although guided electromagnetic waves are highly relevant to applications in integrated optics, no consistent transformation-optical framework has so far been developed for slab waveguides. Indeed, the conventional application of transformation optics to dielectric slab waveguides leads to bulky three-dimensional devices with metamaterial implementations both inside and outside of the waveguide's core. In this contribution, we develop a transformationoptical framework that still results in thin metamaterial waveguide devices consisting of a nonmagnetic metamaterial core of varying thickness [Phys. Rev. B 93.8, 085429 (2016)]. We numerically demonstrate the effectiveness and versatility of our equivalence relations with three crucial functionalities: a beam bender, a beam splitter and a conformal lens. Our devices perform well on a qualitative (comparison of fields) and quantitative (comparison of transmitted power) level compared to their bulky counterparts. As a result, the geometrical toolbox of transformation optics may lead to a plethora of integrated metamaterial devices to route guided waves along optical chips.

  15. Acoustic metamaterial design and applications

    Science.gov (United States)

    Zhang, Shu

    The explosion of interest in metamaterials is due to the dramatically increased manipulation ability over light as well as sound waves. This material research was stimulated by the opportunity to develop an artificial media with negative refractive index and the application in superlens which allows super-resolution imaging. High-resolution acoustic imaging techniques are the essential tools for nondestructive testing and medical screening. However, the spatial resolution of the conventional acoustic imaging methods is restricted by the incident wavelength of ultrasound. This is due to the quickly fading evanescent fields which carry the subwavelength features of objects. By focusing the propagating wave and recovering the evanescent field, a flat lens with negative-index can potentially overcome the diffraction limit. We present the first experimental demonstration of focusing ultrasound waves through a flat acoustic metamaterial lens composed of a planar network of subwavelength Helmholtz resonators. We observed a tight focus of half-wavelength in width at 60.5 KHz by imaging a point source. This result is in excellent agreement with the numerical simulation by transmission line model in which we derived the effective mass density and compressibility. This metamaterial lens also displays variable focal length at different frequencies. Our experiment shows the promise of designing compact and light-weight ultrasound imaging elements. Moreover, the concept of metamaterial extends far beyond negative refraction, rather giving enormous choice of material parameters for different applications. One of the most interesting examples these years is the invisible cloak. Such a device is proposed to render the hidden object undetectable under the flow of light or sound, by guiding and controlling the wave path through an engineered space surrounding the object. However, the cloak designed by transformation optics usually calls for a highly anisotropic metamaterial, which

  16. EDITORIAL: Photonic terahertz technology

    Science.gov (United States)

    Lisauskas, Alvydas; Löffler, Torsten; Roskos, Hartmut G.

    2005-07-01

    In recent years, when reading newspapers and journals or watching TV, one has been able to find feature presentations dealing with the prospects of terahertz (THz) technology and its potential impact on market applications. THz technology aims to fill the THz gap in the electro-magnetic spectrum in order to make the THz frequency regime, which spans the two orders of magnitude from 100 GHz to 10 THz, accessible for applications. From the lower-frequency side, electronics keeps pushing upwards, while photonic approaches gradually improve our technological options at higher frequencies. The popular interest reflects the considerable advances in research in the THz field, and it is mainly advances in the photonic branch, with the highlight being the development of the THz quantum cascade laser, which in recent years have caught the imagination of the public, and of potential users and investors. This special issue of Semiconductor Science and Technology provides an overview of key scientific developments which currently represent the cutting edge of THz photonic technology. In order to be clear about the implications, we should define exactly what we mean by 'THz photonic technology', or synonymously 'THz photonics'. It is characterized by the way in which THz radiation (or a guided THz wave) is generated, namely by the use of lasers. This may be done in one of two fundamentally different schemes: (i) by laser action in the terahertz frequency range itself (THz lasers), or (ii) by down-conversion processes (photomixing) involving the radiation of lasers which operate in the visible, near-infrared or infrared spectral ranges, either in pulsed or continuous-wave mode. The field of THz photonics has grown so considerably that it is out of the question to cover all its aspects in a single special issue of a journal. We have elected, instead, to focus our attention on two types of development with a potentially strong impact on the THz field: first, on significant advances

  17. Photonic crystal nanofiber air-mode cavity with high Q-factor and high sensitivity for refractive index sensing

    Science.gov (United States)

    Ma, Xiaoxue; Chen, Xin; Nie, Hongrui; Yang, Daquan

    2018-01-01

    Recently, due to its superior characteristics and simple manufacture, such as small size, low loss, high sensitivity and convenience to couple, the optical fiber sensor has become one of the most promising sensors. In order to achieve the most effective realization of light propagation by changing the structure of sensors, FOM(S •Q/λres) ,which is determined by two significant variables Q-factor and sensitivity, as a trade-off parameter should be optimized to a high value. In typical sensors, a high Q can be achieved by confining the optical field in the high refractive index dielectric region to make an interaction between analytes and evanescent field of the resonant mode. However, the ignored sensitivity is relatively low with a high Q achieved, which means that the resonant wavelength shift changes non-obviously when the refractive index increases. Meanwhile, the sensitivity also leads to a less desirable FOM. Therefore, a gradient structure, which can enhance the performance of sensors by achieving high Q and high sensitivity, has been developed by Kim et al. later. Here, by introducing parabolic-tapered structure, the light field localized overlaps strongly and sufficiently with analytes. And based on a one-dimensional photonic-crystal nanofiber air-mode cavity, a creative optical fiber sensor is proposed by combining good stability and transmission characteristics of fiber and strengths of tapered structure, realizing excellent FOM {4.7 x 105 with high Q-factors (Q{106) and high sensitivities (<700 nm/RIU).

  18. Handbook of terahertz technologies devices and applications

    CERN Document Server

    Song, Ho-Jin

    2015-01-01

    Terahertz waves, which lie in the frequency range of 0.1-10 THz, have long been investigated in a few limited fields, such as astronomy, because of a lack of devices for their generation and detection. Several technical breakthroughs made over the last couple of decades now allow us to radiate and detect terahertz waves more easily, which has triggered the search for new uses of terahertz waves in many fields, such as bioscience, security, and information and communications technology. The book covers some of the technical breakthroughs in terms of device technologies. It discusses not only th

  19. Terahertz Tools Advance Imaging for Security, Industry

    Science.gov (United States)

    2010-01-01

    Picometrix, a wholly owned subsidiary of Advanced Photonix Inc. (API), of Ann Arbor, Michigan, invented the world s first commercial terahertz system. The company improved the portability and capabilities of their systems through Small Business Innovation Research (SBIR) agreements with Langley Research Center to provide terahertz imaging capabilities for inspecting the space shuttle external tanks and orbiters. Now API s systems make use of the unique imaging capacity of terahertz radiation on manufacturing floors, for thickness measurements of coatings, pharmaceutical tablet production, and even art conservation.

  20. Reversed rainbow with a nonlocal metamaterial

    Energy Technology Data Exchange (ETDEWEB)

    Morgado, Tiago A., E-mail: tiago.morgado@co.it.pt; Marcos, João S.; Silveirinha, Mário G., E-mail: mario.silveirinha@co.it.pt [Department of Electrical Engineering, Instituto de Telecomunicações, University of Coimbra, 3030 Coimbra (Portugal); Costa, João T. [CST AG, Bad Nauheimer Strasse 19, 64289 Darmstadt (Germany); Costa, Jorge R. [Instituto de Telecomunicações and Instituto Universitário de Lisboa (ISCTE-IUL), 1649-026 Lisboa (Portugal); Fernandes, Carlos A. [Instituto de Telecomunicações, and Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal)

    2014-12-29

    One of the intriguing potentials of metamaterials is the possibility to realize a nonlocal electromagnetic reaction, such that the effective medium response at a given point is fundamentally entangled with the macroscopic field distribution at long distances. Here, it is experimentally and numerically verified that a microwave nonlocal metamaterial formed by crossed metallic wires enables a low-loss broadband anomalous material response such that the refractive index decreases with frequency. Notably, it is shown that an electromagnetic beam refracted by our metamaterial prism creates a reversed microwave rainbow.

  1. Magneto-optical response in bimetallic metamaterials

    Science.gov (United States)

    Atmatzakis, Evangelos; Papasimakis, Nikitas; Fedotov, Vassili; Vienne, Guillaume; Zheludev, Nikolay I.

    2018-01-01

    We demonstrate resonant Faraday polarization rotation in plasmonic arrays of bimetallic nano-ring resonators consisting of Au and Ni sections. This metamaterial design allows the optimization of the trade-off between the enhancement of magneto-optical effects and plasmonic dissipation. Nickel sections corresponding to as little as 6% of the total surface of the metamaterial result in magneto-optically induced polarization rotation equal to that of a continuous nickel film. Such bimetallic metamaterials can be used in compact magnetic sensors, active plasmonic components, and integrated photonic circuits.

  2. Plasmonic toroidal excitation with engineering metamaterials

    Science.gov (United States)

    Wu, Pin Chieh; Hsiao, Hui-Hsin; Liao, Chun Yen; Chung, Tsung Lin; Wu, Pei Ru; Savinov, Vassili; Zheludev, Nikolay I.; Tsai, Din Ping

    2017-08-01

    Natural toroidal molecules, such as biomolecules and proteins, possess toroidal dipole moments that are hard to be detected, which leads to extensive studies of artificial toroidal materials. Recently, toroidal metamaterials have been widely investigated to enhance toroidal dipole moments while the other multipoles are eliminated due to the spacial symmetry. In this talk, we will show several cases on the plasmonic toroidal excitation by engineering the near-field coupling between metamaterials, including their promising applications. In addition, a novel design for a toroidal metamaterial with engineering anapole mode will also be discussed.

  3. Magneto-optical response in bimetallic metamaterials

    CERN Document Server

    Atmatzakis, Evangelos; Fedotov, Vassili; Vienne, Guillaume; Zheludev, Nikolay I

    2016-01-01

    We demonstrate resonant Faraday polarization rotation in plasmonic arrays of bimetallic nano-ring resonators consisting of Au and Ni sections. This metamaterial design allows to optimize the trade-off between the enhancement of magneto-optical effects and plasmonic dissipation. Although Ni sections correspond to as little as ~6% of the total surface of the metamaterial, the resulting magneto-optically induced polarization rotation is equal to that of a continuous film. Such bimetallic metamaterials can be used in compact magnetic sensors, active plasmonic components and integrated photonic circuits.

  4. Metamaterial Loadings for Waveguide Miniaturization

    CERN Document Server

    Odabasi, H

    2013-01-01

    We show that a rectangular metallic waveguide loaded with metamaterial elements consisting of electric-field coupled (ELC) resonators placed at the side walls can operate well below the cutoff frequency of the respective unloaded waveguide. The dispersion diagrams indicate that propagating modes in ELC-loaded waveguides are of forward-type for both TE and TM modes. We also study the dispersion diagram and transmission characteristics of rectangular metallic waveguides simultaneously loaded with ELCs and split ring resonators (SRRs). Such doubly-loaded waveguides can support both forward wave and backward waves, and provide independent control of the propagation characteristics for the respective modes.

  5. Graphene hyperlens for terahertz radiation

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Lavrinenko, Andrei; Chigrin, Dmitry N.

    2012-01-01

    We propose a graphene hyperlens for the terahertz (THz) range. We employ and numerically examine a structured graphene-dielectric multilayered stack that is an analog of a metallic wire medium. As an example of the graphene hyperlens in action, we demonstrate an imaging of two point sources...... separated by a distance λ0/5. An advantage of such a hyperlens as compared to a metallic one is the tunability of its properties by changing the chemical potential of graphene. We also propose a method to retrieve the hyperbolic dispersion, check the effective medium approximation, and retrieve...

  6. Pulsed Terahertz Spectroscopy of Biomolecules

    Science.gov (United States)

    Markelz, A. G.; Heilweil, E. J.

    1998-03-01

    Measurements of the collective vibrational modes associated with the 3D tertiary structure of biomolecules were undertaken using pulse terahertz spectroscopy. Transmission measurements of calf thymus DNA (CT-DNA), bovine serum albumin (BSA), and collagen were made for 2 cm-1 to 45 cm-1. For all three biomolecules, low frequency absorption bands could be distinguished from a broadband absorption increasing with frequency. For lyophilized powder samples, features appear at 15 cm-1 and 22 cm-1 for CT-DNA, 10 cm-1 for BSA, and 8 cm-1 and 12 cm-1 for collagen. Measurements were performed as a function of hydration and conformation.

  7. Metamaterial phenomenons via uniform motion

    Science.gov (United States)

    Mackay, Tom G.; Lakhtakia, Akhlesh

    2007-05-01

    Metamaterials offer exotic electromagnetic possibilities, beyond those usually associated with conventional materials. Two general phenomenons associated with metamaterials have attracted much recent attention: negative- phase-velocity (NPV) propagation, and cloaking and invisibility. Relatively simple materials may (i) support NPV propagation, and (ii) offer concealment to a substantial degree, by means of translation at constant velocity. By virtue of the Minkowski constitutive relations, planewave propagation in a homogeneous, instantaneously responding, dielectric-magnetic material that is isotropic in the co-moving reference frame, can be classified as positive-, negative-, and orthogonal-phase-velocity (PPV, NPV, and OPV) propagation in a non-co-moving reference frame, depending upon the magnitude and direction of that reference frame's velocity relative to the material. The perceived lateral position of a transmitted beam, upon propagating at an oblique angle through a slab of homogeneous, instantaneously responding, isotropic, dielectric material, can be controlled via the velocity of the slab. Therefore, by appropriate choice of the slab's velocity, the transmitted beam can emerge from the slab with no lateral shift in position, and a substantial degree of concealment may be achieved.

  8. Self-assembled nanostructured metamaterials

    Science.gov (United States)

    Ponsinet, Virginie; Baron, Alexandre; Pouget, Emilie; Okazaki, Yutaka; Oda, Reiko; Barois, Philippe

    2017-07-01

    The concept of metamaterials emerged in the years 2000 with the achievement of artificial structures enabling nonconventional propagation of electromagnetic waves, such as negative phase velocity or negative refraction. The electromagnetic response of metamaterials is generally based on the presence of optically resonant elements —or meta-atoms— of sub-wavelength size and well-designed morphology so as to provide the desired electric and magnetic optical properties. Top-down technologies based on lithography techniques have been intensively used to fabricate a variety of efficient electric and magnetic resonators operating from microwave to visible light frequencies. However, the technological limits of the top-down approach are reached in visible light where a huge number of nanometre-sized elements is required. We show here that the bottom-up fabrication route based on the combination of nanochemistry and the self-assembly methods of colloidal physics provide an excellent alternative for the large-scale synthesis of complex meta-atoms, as well as for the fabrication of 2D and 3D samples exhibiting meta-properties in visible light. Contribution to the Focus Issue Self-assemblies of Inorganic and Organic Nanomaterials edited by Marie-Paule Pileni.

  9. Metal Mesh Filters for Terahertz Receivers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The technical objective of this SBIR program is to develop and demonstrate metal mesh filters for use in NASA's low noise receivers for terahertz astronomy and...

  10. Investigating murals with terahertz reflective tomography

    Science.gov (United States)

    Yuan, Minjie; Sun, Wenfeng; Wang, Xinke; Wang, Sen; Zhang, Qunxi; Ye, Jiasheng; Zhang, Yan

    2015-08-01

    Terahertz time-domain spectroscopy (THz-TDS) imaging technology has been proposed to be used in the non-invasive detection of murals. THz-TDS images provide structural data of the sample that cannot be obtained with other complementary techniques. In this paper, two types of defects hidden in the plaster used to simulate the cases of defects in the murals, have been investigated by the terahertz reflected time domain spectroscopy imaging system. These preset defects include a leaf slice and a slit built in the plaster. With the terahertz reflective tomography, information about defects has been determined involving the thickness from the surface of sample to the built-in defect, the profile and distribution of the defect. With this THz tomography, different defects with the changes of optical thickness and their relative refractive index have been identified. The application of reflective pulsed terahertz imaging has been extended to the defect detection of the murals.

  11. Research on a multiband metamaterial absorber

    Science.gov (United States)

    Yu, Xiebin; Song, Yaoliang; Fan, Shicheng

    2017-10-01

    This paper describes the design of a multiband metamaterial absorber based on double-gap sheet metal and takes it into simulation by CST microwave studio. The results of simulation show that the metamaterial absorber achieves absorption rate up to 99.6%, 99.8%, 99.9% and 93.5% at 4.64 GHz, 8.67 GHz, 13.93 GHz and 18.53 GHz respectively. The thickness of the metamaterial absorber is just 3.3%, 6.3%, 10.0% and 13.3% of its working wavelength respectively. Finally, the absorption mechanism is analyzed by using the surface current,surface charge and the impedance matching theory. This metamaterial absorber has potential application in multifrequency radar, electromagnetic compatibility of complex electronic platform and so on.

  12. Hyperbolic metamaterial lens with hydrodynamic nonlocal response

    DEFF Research Database (Denmark)

    Yan, Wei; Mortensen, N. Asger; Wubs, Martijn

    2013-01-01

    We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves of the f......We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves...... in the local-response approximation and in the hydrodynamic Drude model can differ considerably. In particular, the optimal frequency for imaging in the nonlocal theory is blueshifted with respect to that in the local theory. Thus, to detect whether nonlocal response is at work in a hyperbolic metamaterial, we...... propose to measure the near-field distribution of a hyperbolic metamaterial lens....

  13. Metamaterial polarization converter analysis: limits of performance

    DEFF Research Database (Denmark)

    Markovich, Dmitry L.; Andryieuski, Andrei; Zalkovskij, Maksim

    2013-01-01

    In this paper, we analyze the theoretical limits of a metamaterial-based converter with orthogonal linear eigenpolarizations that allow linear-to-elliptical polarization transformation with any desired ellipticity and ellipse orientation. We employ the transmission line approach providing a needed...... level of the design generalization. Our analysis reveals that the maximal conversion efficiency for transmission through a single metamaterial layer is 50 %, while the realistic reflection configuration can give the conversion efficiency up to 90 %. We show that a double layer transmission converter...... and a single layer with a ground plane can have 100 % polarization conversion efficiency. We tested our conclusions numerically reaching the designated limits of efficiency using a simple metamaterial design. Our general analysis provides useful guidelines for the metamaterial polarization converter design...

  14. Multifrequency Printed Antennas Loaded with Metamaterial Particles

    Directory of Open Access Journals (Sweden)

    D. Segovia-Vargas

    2009-06-01

    Full Text Available This paper provides a review of printed antennas loaded with metamaterial particles. This novel technique allows developing printed antennas with interesting features such as multifrequency (simultaneous operation over two or more frequency bands and multifunctionality (e. g. radiation pattern diversity. Moreover, compactness is also achieved and the main advantages of conventional printed antennas (light weight, low profile, low cost ... are maintained. Different types of metamaterial-loaded printed antennas are reviewed: printed dipoles and patch antennas. Several prototypes are designed, manufactured and measured showing good results. Furthermore, simple but accurate equivalent models are proposed. These models allow an easy and quick design of metamaterial-loaded printed antennas. Finally, two interesting applications based on the proposed antennas are reviewed: the patch antennas are used as radiating elements of emerging active RFID systems in the microwave band and the metamaterial-loaded printed dipoles are employed to increase the performance of log-periodic arrays.

  15. Microwave mode structure of superconducting metamaterial resonators

    Science.gov (United States)

    Wang, Haozhi; Rouxinol, Francisco; Lahaye, Matthew; Plourde, Britton

    2015-03-01

    Arrays of lumped circuit elements can be used to form metamaterial resonant structures that exhibit novel behavior compared to resonators made from conventional distributed transmission lines. By engineering the parameters and configurations of the lumped elements composing the unit cell of such a metamaterial resonator, one can generate spectra with wide stop-bands as well as pass-bands with dense microwave modes. If the metamaterials are fabricated from superconducting traces, the losses can be low enough to allow for these dense modes to be resolved and potentially coupled to quantum systems, such as superconducting qubits. We will present our low-temperature measurements of a variety of superconducting metamaterial resonators and we will compare these with numerical simulations of the microwave properties.

  16. Interferometric direction finding with a metamaterial detector

    Energy Technology Data Exchange (ETDEWEB)

    Venkatesh, Suresh; Schurig, David, E-mail: david.schurig@utah.edu [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Shrekenhamer, David; Padilla, Willie [Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States); Xu, Wangren; Sonkusale, Sameer [Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155 (United States)

    2013-12-16

    We present measurements and analysis demonstrating useful direction finding of sources in the S band (2–4 GHz) using a metamaterial detector. An augmented metamaterial absorber that supports magnitude and phase measurement of the incident electric field, within each unit cell, is described. The metamaterial is implemented in a commercial printed circuit board process with off-board back-end electronics. We also discuss on-board back-end implementation strategies. Direction finding performance is analyzed for the fabricated metamaterial detector using simulated data and the standard algorithm, MUtiple SIgnal Classification. The performance of this complete system is characterized by its angular resolution as a function of radiation density at the detector. Sources with power outputs typical of mobile communication devices can be resolved at kilometer distances with sub-degree resolution and high frame rates.

  17. Metamaterial with electromagnetic transparency under multiband absorptions

    Science.gov (United States)

    Zhang, Xu; Qi, Limei

    2017-02-01

    We propose a metal-dielectric-metal (MDM) metamaterial that has an electromagnetic (EM) transparency spectrum under multiband absorptions in the C and the X bands. The ground continuous metal film used in the conventional metamaterial absorber (MA) is replaced by a structured ground plane (SGP) in our design. The band-pass properties of the front patterned metal film and the SGP determine the EM transparency spectrum, while the magnetic and the electric resonances in the MDM structure contribute to the multiband absorptions. Due to the symmetric structure of the unit cell, the absorption bands and the EM transparency spectrum of the metamaterial have the property of polarization independency. Despite the normal incidence, the metamaterial can also be used for non-normal incidence.

  18. Frequency-Temperature Compensation Techniques for High-Q Microwave Resonators

    Science.gov (United States)

    Hartnett, John G.; Tobar, Michael E.

    Low-noise high-stability resonator oscillators based on high-Q monolithic sapphire ``Whispering Gallery'' (WG)-mode resonators have become important devices for telecommunication, radar and metrological applications. The extremely high quality factor of sapphire, of 2 x10^5 at room temperature, 5 x10^7 at liquid nitrogen temperature and 5 x10^9 at liquid helium temperature has enabled the lowest phase noise and highly frequency-stable oscillators in the microwave regime to be constructed. To create an oscillator with exceptional frequency stability, the resonator must have its frequency-temperature dependence annulled at some temperature, as well as a high quality factor. The Temperature Coefficient of Permittivity (TCP) for sapphire is quite large, at 10-100parts per million/K above 77K. This mechanism allows temperature fluctuations to transform to resonator frequency fluctuations.A number of research groups worldwide have investigated various methods of compensating the TCP of a sapphire dielectric resonator at different temperatures. The usual electromagnetic technique of annulment involves the use of paramagnetic impurities contributing an opposite temperature coefficient of the magnetic susceptibility to the TCP. This technique has only been realized successfully in liquid helium environments. Near 4K the thermal expansion and permittivity effects are small and only small quantities of the paramagnetic ions are necessary to compensate the mode frequency. Compensation is due to impurity ions that were incidentally left over from the manufacturing process.Recently, there has been an effort to dispense with the need for liquid helium and make a compact flywheel oscillator for the new generation of primary frequency standards such as the cesium fountain at the Laboratoire Primaire du Temps et des Fréquences (LPTF), France. To achieve the stability limit imposed by quantum projection noise requires that the local oscillator stability is of the order of 10

  19. Nano-optomechanical Nonlinear Dielectric Metamaterials

    CERN Document Server

    Karvounis, Artemios; MacDonald, Kevin F; Zheludev, Nikolay I

    2015-01-01

    By harnessing the resonant nature of localized electromagnetic modes in a nanostructured silicon membrane, an all-dielectric metamaterial can act as nonlinear medium at optical telecommunications wavelengths. We show that such metamaterials provide extremely large optomechanical nonlinearities, operating at intensities of only a few {\\mu}W per unit cell and modulation frequencies as high as 152 MHz, thereby offering a path to fast, lossless, compact and energy efficient all-optical metadevices.

  20. Optical Propagation in Anisotropic Metamaterials (Postprint)

    Science.gov (United States)

    2017-02-22

    OPTICAL PROPAGATION ANALYSIS USING BERREMAN MATRIX METHOD Figure 2 shows a TM polarized plane wave propagating in the − plane from free space...respectively, inside the anisotropic metamaterial. TM represents the component of the wave vector in the metamaterial for TM polarization and...or alternatively, refractive index and characteristic impedance. These properties depend not only on the wavelength and polarization but also the