WorldWideScience

Sample records for nonlinear fano resonance

  1. Multi-bi- and tri-stability using nonlinear plasmonic Fano resonators

    KAUST Repository

    Amin, Muhammad

    2013-09-01

    A plasmonic Fano resonator embedding Kerr nonlinearity is used to achieve multi-bi- and tri-stability. Fano resonance is obtained by inducing higher-order plasmon modes on metallic surfaces via geometrical symmetry breaking. The presence of the multiple higher order plasmon modes provides the means for producing multi-bi- or tri-stability in the response of the resonator when it is loaded with a material with Kerr nonlinearity. The multi-stability in the response of the proposed resonator enables its use in three-state all optical memory and switching applications. © 2013 IEEE.

  2. Acoustic Fano resonators

    KAUST Repository

    Amin, Muhammad

    2014-07-01

    The resonances with asymmetric Fano line-shapes were originally discovered in the context of quantum mechanics (U. Fano, Phys. Rev., 124, 1866-1878, 1961). Quantum Fano resonances were generated from destructive interference of a discrete state with a continuum one. During the last decade this concept has been applied in plasmonics where the interference between a narrowband polariton and a broader one has been used to generate electromagnetically induced transparency (EIT) (M. Rahmani, et al., Laser Photon. Rev., 7, 329-349, 2013).

  3. Reconfigurable nonreciprocity with nonlinear Fano diode

    OpenAIRE

    Xu, Yi; Miroshnichenko, Andrey E.

    2013-01-01

    We propose a dynamically tunable nonreciprocal response for wave propagations by employing nonlinear Fano resonances. We demonstrate that transmission contrast of waves propagation in opposite directions can be controlled by excitation signal. In particular, the unidirectional transmission can be flipped at different times of a pulse, resembling a diode operation with {\\em dynamical reconfigurable nonreciprocity}. The key mechanism is the interaction between the linear and nonlinear Fano reso...

  4. All-electrical nonlinear fano resonance in coupled quantum point contacts

    Science.gov (United States)

    Xiao, Shiran

    This thesis is motivated by recent interest in the Fano resonance (FR). As a wave-interference phenomenon, this resonance is of increasing importance in optics, plasmon-ics, and metamaterials, where its ability to cause rapid signal modulations under variation of some suitable parameter makes it desirable for a variety of applications. In this thesis, I focus on a novel manifestation of this resonance in systems of coupled quantum point contacts (QPCs). The major finding of this work is that the FR in this system may be ma-nipulated by applying a nonlinear DC bias to the system. Under such conditions, we are able to induce significant distortions of resonance lineshape, providing a pathway to all-electrical manipulation of the FR. To interpret this behavior we apply a recently-developed model for a three-path FR, involving an additional "intruder" continuum. We have previously used this model to account for the magnetic-field induced distortions of the FR observed in coupled QPCs, and show here that this model also provides a frame-work for understanding the observed nonlinear behavior. Our work therefore reveals a new manifestation of the FR that can be sensitively tailored by external control, a finding that may eventually allow the application of this feature to nanoelectronics. Since the in-terference scheme involves in this thesis is a completely general one, it should be broadly applicable across a variety of different wave-based systems, including those in both pho-tonics and electronics and opening up the possibility of new applications in areas such as chemical and biological sensing and secure communications.

  5. Polaronic quasiparticle picture for generation dynamics of coherent phonons in semiconductors: Transient and nonlinear Fano resonance

    Science.gov (United States)

    Watanabe, Yohei; Hino, Ken-ichi; Hase, Muneaki; Maeshima, Nobuya

    2017-01-01

    We examine generation dynamics of coherent phonons in both polar and nonpolar semiconductors, such as GaAs and Si, based on a polaronic-quasiparticle (PQ) model. In this model, the PQ operator is composed of two kinds of operators: one is a quasiboson operator, defined as a linear combination of a set of pairs of electron operators, and the other is a longitudinal optical (LO) phonon operator. In particular, the problem of transient and nonlinear Fano resonance (FR) is tackled, where the vestige of this quantum interference effect was observed exclusively in lightly n -doped Si immediately after carriers were excited by an ultrashort pulse laser [M. Hase et al., Nature (London) 426, 51 (2003), 10.1038/nature02044], although not observed yet in GaAs. The PQ model enables us to show straightforwardly that the phonon energy state is embedded in continuum states formed by a set of adiabatic eigenstates of the quasiboson; this energy configuration is a necessary condition of the manifestation of the transient FR in the present optically nonlinear system. Numerical calculations are done for photoemission spectra relevant to the retarded longitudinal dielectric function of transient photoexcited states and for power spectra relevant to the LO-phonon displacement function of time. The photoemission spectra show that in undoped Si, an asymmetric spectral profile characteristic of FR comes into existence immediately after the instantaneous carrier excitation to fade out gradually, whereas in undoped GaAs, no asymmetry in spectra appears in the whole temporal region. The similar results are also obtained in the power spectra. These results are in harmony with the reported experimental results. It is found that the obtained difference in spectral profile between undoped Si and GaAs is attributed to a phase factor of an effective interaction between the LO phonon and the quasiboson. More detailed discussion of the FR dynamics is made in the text.

  6. Fano resonances from gradient-index metamaterials.

    Science.gov (United States)

    Xu, Yadong; Li, Sucheng; Hou, Bo; Chen, Huanyang

    2016-01-27

    Fano resonances - resonant scattering features with a characteristic asymmetric profile - have generated much interest, due to their extensive and valuable applications in chemical or biological sensors, new types of optical switches, lasers and nonlinear optics. They have been observed in a wide variety of resonant optical systems, including photonic crystals, metamaterials, metallic gratings and nanostructures. In this work, a waveguide structure is designed by employing gradient-index metamaterials, supporting strong Fano resonances with extremely sharp spectra. As the changes in the transmission spectrum originate from the interaction of guided modes from different channels, instead of resonance structures or metamolecules, the Fano resonances can be observed for both transverse electric and transverse magnetic polarizations. These findings are verified by fine agreement with analytical calculations and experimental results at microwave, as well as simulated results at near infrared frequencies.

  7. Slope tunable Fano resonances in asymmetric embedded microring resonators

    Science.gov (United States)

    Wang, Gencheng; Dai, Tingge; Jiang, Jianfei; Yu, Hui; Hao, Yinlei; Wang, Yuehai; Li, Yubo; Jiang, Xiaoqing; Yang, Jianyi

    2017-02-01

    An asymmetric embedded microring resonant system is proposed and fabricated on a silicon-on-insulator (SOI) to achieve slope tunable Fano resonances. The Fano resonances originate from the nonlinear phase shift produced by adding an inner ring coupling with the outer ring. The slope of the Fano resonance can be well tuned to be ultra-high by controlling the microheaters to adjust the phase condition. Experimentally, we observe Fano resonance with a maximum extinction ratio of about 40 dB, and the slope can be tuned from -35 dB nm-1 to -93 dB nm-1, which shows good agreement with the theoretical analysis. This device could find potential applications in ultra-high sensitivity sensing systems.

  8. Universal formalism of Fano resonance

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Liang [School of Physical Science and Technology and Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, Gansu 730000 (China); Lai, Ying-Cheng [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States); Institute for Complex Systems and Mathematical Biology, King’s College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Luo, Hong-Gang [School of Physical Science and Technology and Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, Gansu 730000 (China); Beijing Computational Science Research Center, Beijing 100084 (China); Grebogi, Celso [Institute for Complex Systems and Mathematical Biology, King’s College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom)

    2015-01-15

    The phenomenon of Fano resonance is ubiquitous in a large variety of wave scattering systems, where the resonance profile is typically asymmetric. Whether the parameter characterizing the asymmetry should be complex or real is an issue of great experimental interest. Using coherent quantum transport as a paradigm and taking into account of the collective contribution from all available scattering channels, we derive a universal formula for the Fano-resonance profile. We show that our formula bridges naturally the traditional Fano formulas with complex and real asymmetry parameters, indicating that the two types of formulas are fundamentally equivalent (except for an offset). The connection also reveals a clear footprint for the conductance resonance during a dephasing process. Therefore, the emergence of complex asymmetric parameter when fitting with experimental data needs to be properly interpreted. Furthermore, we have provided a theory for the width of the resonance, which relates explicitly the width to the degree of localization of the close-by eigenstates and the corresponding coupling matrices or the self-energies caused by the leads. Our work not only resolves the issue about the nature of the asymmetry parameter, but also provides deeper physical insights into the origin of Fano resonance. Since the only assumption in our treatment is that the transport can be described by the Green’s function formalism, our results are also valid for broad disciplines including scattering problems of electromagnetic waves, acoustics, and seismology.

  9. Universal formalism of Fano resonance

    Directory of Open Access Journals (Sweden)

    Liang Huang

    2015-01-01

    Full Text Available The phenomenon of Fano resonance is ubiquitous in a large variety of wave scattering systems, where the resonance profile is typically asymmetric. Whether the parameter characterizing the asymmetry should be complex or real is an issue of great experimental interest. Using coherent quantum transport as a paradigm and taking into account of the collective contribution from all available scattering channels, we derive a universal formula for the Fano-resonance profile. We show that our formula bridges naturally the traditional Fano formulas with complex and real asymmetry parameters, indicating that the two types of formulas are fundamentally equivalent (except for an offset. The connection also reveals a clear footprint for the conductance resonance during a dephasing process. Therefore, the emergence of complex asymmetric parameter when fitting with experimental data needs to be properly interpreted. Furthermore, we have provided a theory for the width of the resonance, which relates explicitly the width to the degree of localization of the close-by eigenstates and the corresponding coupling matrices or the self-energies caused by the leads. Our work not only resolves the issue about the nature of the asymmetry parameter, but also provides deeper physical insights into the origin of Fano resonance. Since the only assumption in our treatment is that the transport can be described by the Green’s function formalism, our results are also valid for broad disciplines including scattering problems of electromagnetic waves, acoustics, and seismology.

  10. Tuning Fano Resonances with Graphene

    DEFF Research Database (Denmark)

    Emani, Naresh K.; Chung, Ting-Fung; Prokopeva, Ludmila

    2013-01-01

    We demonstrate strong electrical control of plasmonic Fano resonances in dolmen structures using tunable interband transitions in graphene. Such graphene-plasmonic hybrid devices can have applications in light modulation and sensing. OCIS codes: (250.5403) Plasmonics; (160.4670) Optical materials...

  11. Quantum Generation Dynamics of Coherent Phonon in Semiconductors: Transient and Nonlinear Fano Resonance

    Science.gov (United States)

    Watanabe, Yohei; Hino, Ken-Ichi; Hase, Muneaki; Maeshima, Nobuya

    The coherent phonon (CP) generation is one of the representative phenomena induced by ultrashort pulsed laser. In particular, in the initial stage of the CP generation in lightly n-doped Si, the vestige of Fano resonance (FR) manifested in a flash was observed in time-resolved spectroscopy experiments, in which it was speculated that this phenomenon results from the birth of transient polaronic quasiparticles composed of electrons and phonons strongly interacting each other. This study is aimed at constructing a fully-quantum-mechanical model for the CP generation and tracking the origin of the transient FR. We calculate two physical quantities in both of polar and non-polar semiconductors such as GaAs and undoped Si. One is a retarded longitudinal susceptibility which allows one to calculate a transient induced photoemission spectrum. The other is the Fourier-transform of LO-phonon displacement into frequency domain. We have succeeded in showing that the transient FR is exclusively caused in Si in harmony with the experiments, though, not observed in GaAs.

  12. Holographic Kondo and Fano Resonances

    CERN Document Server

    Erdmenger, Johanna; O'Bannon, Andy; Papadimitriou, Ioannis; Probst, Jonas; Wu, Jackson M S

    2016-01-01

    We use holography to study a $(1+1)$-dimensional Conformal Field Theory (CFT) coupled to an impurity. The CFT is an $SU(N)$ gauge theory at large $N$, with strong gauge interactions. The impurity is an $SU(N)$ spin. We trigger an impurity Renormalization Group (RG) flow via a Kondo coupling. The Kondo effect occurs only below the critical temperature of a large-$N$ mean-field transition. We show that at all temperatures $T$, spectral functions of certain bosonic operators exhibit a Fano resonance, which in the low-$T$ phase is a large-$N$ manifestation of the Kondo resonance. Such Fano resonances are characteristic features of RG flows between $(0+1)$-dimensional fixed points, and are thus distinct from those observed for example in quantum dots.

  13. Improved switching using Fano resonances in photonic crystal structures

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Kristensen, Philip Trøst; Elesin, Yuriy;

    2013-01-01

    We present a simple and robust structure for realizing asymmetric Fano transmission characteristics in photonic crystal waveguide-cavity structures. The use of Fano resonances for optical switching is analyzed using temporal coupled mode theory in combination with three-dimensional finite...... difference time domain simulations taking into account the signal bandwidth. The results suggest a significant energy reduction by employing Fano resonances compared to more well established Lorentzian resonance structures. A specific example of a Kerr nonlinearity shows an order of magnitude energy...

  14. Structural Colors from Fano Resonances

    CERN Document Server

    Shen, Yichen; Wang, Imbert; Stelmakh, Veronika; Joannopoulos, John D; Soljacic, Marin

    2014-01-01

    Structural coloration is an interference phenomenon where colors emerge when visible light interacts with nanoscopically structured material, and has recently become a most interesting scientific and engineering topic. However, current structural color generation mechanisms either require thick (compared to the wavelength) structures or lack dynamic tunability. This report proposes a new structural color generation mechanism, that produces colors by the Fano resonance effect on thin photonic crystal slab. We experimentally realize the proposed idea by fabricating the samples that show resonance-induced colors with weak dependence on the viewing angle. Finally, we show that the resonance-induced colors can be dynamically tuned by stretching the photonic crystal slab fabricated on an elastic substrate.

  15. Fano resonance Rabi splitting of surface plasmons.

    Science.gov (United States)

    Liu, Zhiguang; Li, Jiafang; Liu, Zhe; Li, Wuxia; Li, Junjie; Gu, Changzhi; Li, Zhi-Yuan

    2017-08-14

    Rabi splitting and Fano resonance are well-known physical phenomena in conventional quantum systems as atoms and quantum dots, arising from strong interaction between two quantum states. In recent years similar features have been observed in various nanophotonic and nanoplasmonic systems. Yet, realization of strong interaction between two or more Fano resonance states has not been accomplished either in quantum or in optical systems. Here we report the observation of Rabi splitting of two strongly coupled surface plasmon Fano resonance states in a three-dimensional plasmonic nanostructure consisting of vertical asymmetric split-ring resonators. The plasmonic system stably supports triple Fano resonance states and double Rabi splittings can occur between lower and upper pairs of the Fano resonance states. The experimental discovery agrees excellently with rigorous numerical simulations, and is well explained by an analytical three-oscillator model. The discovery of Fano resonance Rabi splitting could provide a stimulating insight to explore new fundamental physics in analogous atomic systems and could be used to significantly enhance light-matter interaction for optical sensing and detecting applications.

  16. Anticrossing double Fano resonances generated in metallic/dielectric hybrid nanostructures using nonradiative anapole modes for enhanced nonlinear optical effects.

    Science.gov (United States)

    Zhai, Wu-Chao; Qiao, Tie-Zhu; Cai, Dong-Jin; Wang, Wen-Jie; Chen, Jing-Dong; Chen, Zhi-Hui; Liu, Shao-Ding

    2016-11-28

    Third-harmonic generation with metallic or dielectric nanoparticles often suffer from, respectively, small modal volumes and weak near-field enhancements. This study propose and demonstrate that a metallic/dielectric hybrid nanostructure composed of a silver double rectangular nanoring and a silicon square nanoplate can be used to overcome these obstacles for enhanced third-harmonic generation. It is shown that the nonradiative anapole mode of the Si plate can be used as a localized source to excite the dark subradiant octupole mode of the Ag ring, and the mode hybridization leads to the formation of an antibonding and a bonding subradiant collective mode, thereby forming anticrossing double Fano resonances. With the strong coupling between individual particles and the effectively suppressed radiative losses of the Fano resonances, several strong hot spots are generated around the Ag ring due to the excitation of the octupole mode, and electromagnetic fields within the Si plate are also strongly amplified, making it possible to confine more incident energy inside the dielectric nanoparticle. Calculation results reveal that the confined energy inside the Si plate and the Ag ring for the hybrid structures can be about, respectively, more than three times and four orders stronger than that of the corresponding isolated nanoparticles, which makes the designed hybrid nanostructure a promising platform for enhanced third-harmonic generation.

  17. Fano resonances in scattering: an alternative perspective

    CERN Document Server

    Schwarz, Lukas; Wunner, Günter; Heiss, Walter Dieter; Main, Jörg

    2015-01-01

    In a previous paper it has been shown that the interference of the first and second order pole of the Green's function at an exceptional point, as well as the interference of the first order poles in the vicinity of the exceptional point, gives rise to asymmetric scattering cross section profiles. In the present paper we demonstrate that these line profiles are indeed well described by the Beutler-Fano formula, and thus are genuine Fano resonances. Also further away from the exceptional points excellent agreement can be found by introducing energy dependent Fano parameters.

  18. Phase-controlled Fano resonance by the nanoscale optomechanics

    CERN Document Server

    Zhang, Jian-Qi; Xia, Keyu; Dai, Zhi-Ping; Yang, Wen; Gong, Shangqing; Feng, Mang

    2014-01-01

    Observation of the Fano line shapes is essential to understand properties of the Fano resonance in different physical systems. We explore a tunable Fano resonance by tuning the phase shift in a Mach-Zehnder interferometer (MZI) based on a single-mode nano-optomechanical cavity. The Fano resonance is resulted from the optomechanically induced transparency caused by a nano-mechanical resonator and can be tuned by applying an optomechanical MZI. By tuning the phase shift in one arm of the MZI, we can observe the periodically varying line shapes of the Fano resonance, which represents an elaborate manipulation of the Fano resonance in the nanoscale optomechanics.

  19. Fano resonances in dielectric, metallic and metamaterial photonic structures

    CERN Document Server

    Markos, Peter

    2016-01-01

    We investigate numerically Fano resonances excited in periodic arrays of dielectric, metallic and left-handed cylinders. Of particular interest are Fano resonances excited in the linear array of cylin- ders. We analyze spatial distribution and symmetry of electromagnetic field and discuss the relation between observed Fano resonances and frequency spectra of two-dimensional arrays of cylinders.

  20. Photonic crystal Fano resonances for realizing optical switches, lasers and non-reciprocal elements

    DEFF Research Database (Denmark)

    Bekele, Dagmawi Alemayehu; Yu, Yi; Hu, Hao

    2017-01-01

    structure in combination with cavity-enhanced nonlinearity can be used to realize non-reciprocal transmission at ultra-low power and with large bandwidth. A novel type of laser structure, denoted a Fano laser, is discussed in which one of the mirrors is based on a Fano resonance. Finally, the design...

  1. Demonstration of sharp multiple Fano resonances in optical metamaterials.

    Science.gov (United States)

    Moritake, Yuto; Kanamori, Yoshiaki; Hane, Kazuhiro

    2016-05-01

    We experimentally demonstrated multiple Fano resonances in optical metamaterials. By combination of two different sized asymmetric-double-bar (ADB) structures, triple Fano resonance was observed in the near-infrared region. In addition to Fano resonance due to anti-phase modes in isolated ADB structures, an anti-phase mode due to coupling among different sized ADBs was observed. Dependence of characteristics of resonances on size difference was also investigated. At specific conditions of size difference, quality factors of three Fano resonances were improved compared with ADB metamaterials consisting of one kind of ADBs. The results will help to realize applications using metamaterial resonators with multiple functionalities and high performance.

  2. Polarization-tailored Fano interference in plasmonic crystals: A Mueller matrix model of anisotropic Fano resonance

    CERN Document Server

    Ray, S K; Singh, A K; Kumar, A; Misra, A Mandal S; Mitra, P; Ghosh, N

    2016-01-01

    We present a simple yet elegant Mueller matrix approach for controlling the Fano interference effect and engineering the resulting asymmetric spectral line shape in anisotropic optical system. The approach is founded on a generalized model of anisotropic Fano resonance, which relates the spectral asymmetry to two physically meaningful and experimentally accessible parameters of interference, namely, the Fano phase shift and the relative amplitudes of the interfering modes. The differences in these parameters between orthogonal linear polarizations in an anisotropic system are exploited to desirably tune the Fano spectral asymmetry using pre- and post-selection of optimized polarization states. Experimental control on the Fano phase and the relative amplitude parameters and resulting tuning of spectral asymmetry is demonstrated in waveguided plasmonic crystals using Mueller matrix-based polarization analysis. The approach enabled tailoring of several exotic regimes of Fano resonance including the complete reve...

  3. Fano Resonances observed in Helium Nanodroplets

    CERN Document Server

    LaForge, A C; Jabbari, G; Gokhberg, K; Kryzhevoi, N V; Krishnan, S R; Hess, M; O'Kee?e, P; Ciavardini, A; Prince, K C; Richter, R; Moshammer, R; Cederbaum, L S; Pfeifer, T; Stienkemeier, F; Mudrich, M

    2015-01-01

    Doubly-excited Rydberg states of helium (He) nanodroplets have been studied using synchrotron radiation. We observed Fano resonances related to the atomic N = 2,0 series as a function of droplet size. Although similar qualitatively to their atomic counterparts, the resonance lines are broader and exhibit a shift in energy which increases for the higher excited states. Furthermore, additional resonances are observed which are not seen in atomic systems. We discuss these features in terms of delocalized atomic states perturbed by the surrounding He atoms and compare to singly excited droplets.

  4. Mie scattering as a cascade of Fano resonances.

    Science.gov (United States)

    Rybin, Mikhail V; Samusev, Kirill B; Sinev, Ivan S; Semouchkin, George; Semouchkina, Elena; Kivshar, Yuri S; Limonov, Mikhail F

    2013-12-02

    We reveal that the resonant Mie scattering by high-index dielectric nanoparticles can be presented through cascades of Fano resonances. We employ the exact solution of Maxwell's equations and demonstrate that the Lorenz-Mie coefficients of the Mie problem can be expressed generically as infinite series of Fano functions as they describe interference between the background radiation originated from an incident wave and narrow-spectrum Mie scattering modes that lead to Fano resonances.

  5. Integrated plasmonic refractometric sensor using Fano resonance

    Science.gov (United States)

    Sherif, S. M.; Zografopoulos, D. C.; Shahada, L. A.; Beccherelli, R.; Swillam, M.

    2017-02-01

    We propose a plasmonic refractometric sensor that is based on Fano resonances excited in a resonant rectangular cavity coupled to a metal-insulator-metal bus waveguide. The properties of the resonances are controlled by varying the dimensions of the rectangular resonator and the observed Fano profile stems from the multimode interference of resonant cavity modes. We theoretically investigate the device’s performance as a highly sensitive refractometric plasmonic sensor which operates on gases, water and organic solvent solutions with tens of femtoliters of analyte. The sensor is studied in a wide operational range (0.7-2.7 μm) covering the entire near infrared spectral range, and is characterized by large sensitivity, which reaches 1550 nm RIU-1, and sensitivity per unit volume higher than 107 nm (RIU · nl)-1 at the resonant wavelength of 1.55 μm. The proposed plasmonic structure is very promising for integrated sensing applications owing to its small footprint and surprisingly simple layout.

  6. Coherent Fano resonances in a plasmonic nanocluster enhance optical four-wave mixing

    Science.gov (United States)

    Zhang, Yu; Wen, Fangfang; Zhen, Yu-Rong; Nordlander, Peter; Halas, Naomi J.

    2013-01-01

    Plasmonic nanoclusters, an ordered assembly of coupled metallic nanoparticles, support unique spectral features known as Fano resonances due to the coupling between their subradiant and superradiant plasmon modes. Within the Fano resonance, absorption is significantly enhanced, giving rise to highly localized, intense near fields with the potential to enhance nonlinear optical processes. Here, we report a structure supporting the coherent oscillation of two distinct Fano resonances within an individual plasmonic nanocluster. We show how this coherence enhances the optical four-wave mixing process in comparison with other double-resonant plasmonic clusters that lack this property. A model that explains the observed four-wave mixing features is proposed, which is generally applicable to any third-order process in plasmonic nanostructures. With a larger effective susceptibility χ(3) relative to existing nonlinear optical materials, this coherent double-resonant nanocluster offers a strategy for designing high-performance third-order nonlinear optical media. PMID:23690571

  7. Dynamically tunable Fano resonance in periodically asymmetric graphene nanodisk pair

    CERN Document Server

    Zhang, Zhengren; Fan, Yuancheng; Yin, Pengfei; Zhang, Liwei; Shi, Xi

    2015-01-01

    We present a dynamically frequency tunable Fano resonance planar device composed of periodically asymmetric graphene nanodisk pair for the mid-infrared region. There are two kinds of modes in this structure, that is, the symmetric mode and the antisymmetric mode. The resonance coupling between the symmetric and antisymmetric modes creates a classical Fano resonance. Both of the Fano resonance amplitude and frequency of the structure can be dynamically controlled by varying the Fermi energy of graphene. Resonance transition in the structure is studied to reveal the physical mechanism behind the dynamically tunable Fano resonance. The features of the Fano resonant graphene nanostructures should have promising applications in tunable THz filters, switches, and modulators.

  8. 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

  9. Excitation and tuning of Fano-like cavity plasmon resonances in dielectric-metal core-shell resonators

    Science.gov (United States)

    Gu, Ping; Wan, Mingjie; Wu, Wenyang; Chen, Zhuo; Wang, Zhenlin

    2016-05-01

    Fano resonances have been realized in plasmonic systems and have found intriguing applications, in which, however, precisely controlled symmetry breaking or particular arrangement of multiple constituents is usually involved. Although simple core-shell type architectures composed of a spherical dielectric core and a concentric metallic shell layer have been proposed as good candidates that support inherent Fano resonances, these theoretical predictions have rarely seen any detailed experimental investigation. Here, we report on the experimental investigation of the magnetic and electric-based multipolar plasmonic Fano resonances in the dielectric-metal core-shell resonators that are formed by wrapping a nearly perfect metal shell layer around a dielectric sphere. We demonstrate that these Fano resonances originate from the interference between the Mie cavity and sphere plasmon resonances. Moreover, we present that the variation on either the dielectric core size or core refractive index allows for easily tuning the observed Fano resonances over a wide spectral range. Our findings are supported by excellent agreement with analytical calculations, and offer unprecedented opportunities for realizing ultrasensitive bio-sensors, lasing and nonlinear optical devices.Fano resonances have been realized in plasmonic systems and have found intriguing applications, in which, however, precisely controlled symmetry breaking or particular arrangement of multiple constituents is usually involved. Although simple core-shell type architectures composed of a spherical dielectric core and a concentric metallic shell layer have been proposed as good candidates that support inherent Fano resonances, these theoretical predictions have rarely seen any detailed experimental investigation. Here, we report on the experimental investigation of the magnetic and electric-based multipolar plasmonic Fano resonances in the dielectric-metal core-shell resonators that are formed by wrapping a

  10. Improving nanocavity switching using Fano resonances in photonic crystal structures

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Kristensen, Philip Trøst; Elesin, Yuriy;

    2013-01-01

    We present a simple design for achieving Fano resonances in photonic crystal coupled waveguide-cavity structures. A coupled mode theory analysis shows an order of magnitude reduction in switching energy compared to conventional Lorentz resonances.......We present a simple design for achieving Fano resonances in photonic crystal coupled waveguide-cavity structures. A coupled mode theory analysis shows an order of magnitude reduction in switching energy compared to conventional Lorentz resonances....

  11. Analysis and modeling of Fano resonances using equivalent circuit elements.

    Science.gov (United States)

    Lv, Bo; Li, Rujiang; Fu, Jiahui; Wu, Qun; Zhang, Kuang; Chen, Wan; Wang, Zhefei; Ma, Ruyu

    2016-08-22

    Fano resonance presents an asymmetric line shape formed by an interference of a continuum coupled with a discrete autoionized state. In this paper, we show several simple circuits for Fano resonances from the stable-input impedance mechanism, where the elements consisting of inductors and capacitors are formulated for various resonant modes, and the resistor represents the damping of the oscillators. By tuning the pole-zero of the input impedance, a simple circuit with only three passive components e.g. two inductors and one capacitor, can exhibit asymmetric resonance with arbitrary Q-factors flexiblely. Meanwhile, four passive components can exhibit various resonances including the Lorentz-like and reversely electromagnetically induced transparency (EIT) formations. Our work not only provides an intuitive understanding of Fano resonances, but also pave the way to realize Fano resonaces using simple circuit elements.

  12. Fano resonance between Mie and Bragg scattering in photonic crystals.

    Science.gov (United States)

    Rybin, M V; Khanikaev, A B; Inoue, M; Samusev, K B; Steel, M J; Yushin, G; Limonov, M F

    2009-07-10

    We report the observation of a Fano resonance between continuum Mie scattering and a narrow Bragg band in synthetic opal photonic crystals. The resonance leads to a transmission spectrum exhibiting a Bragg dip with an asymmetric profile, which can be tunably reversed to a Bragg rise. The Fano asymmetry parameter is linked with the dielectric contrast between the permittivity of the filler and the specific value determined by the opal matrix. The existence of the Fano resonance is directly related to disorder due to nonuniformity of a-SiO2 opal spheres. The theoretical "quasi-3D" model produces results in excellent agreement with the experimental data.

  13. Nonlinear Fano Profiles in the Optical Second-Harmonic Generation from Silver Nanoparticles

    CERN Document Server

    Butet, J; Russier-Antoine, I; Bertorelle, F; Mosset, A; Lascoux, N; Jonin, C; Benichou, E; Brevet, P -F

    2012-01-01

    The resonance effects on the optical second harmonic generation from 140 nm silver nanoparticles is studied experimentally by hyper-Rayleigh scattering and numerically by finite element method calculations. We find that the interferences between the broad dipolar and narrow octupolar surface plasmon resonances leads to nonlinear Fano profiles that can be externally controlled by the incident polarization angle. These profiles are responsible for the nonlinear plasmon-induced transparency in the second harmonic generation.

  14. Detecting weak coupling in mesoscopic systems with a nonequilibrium Fano resonance

    Science.gov (United States)

    Xiao, S.; Yoon, Y.; Lee, Y.-H.; Bird, J. P.; Ochiai, Y.; Aoki, N.; Reno, J. L.; Fransson, J.

    2016-04-01

    A critical aspect of quantum mechanics is the nonlocal nature of the wave function, a characteristic that may yield unexpected coupling of nominally isolated systems. The capacity to detect this coupling can be vital in many situations, especially those in which its strength is weak. In this work, we address this problem in the context of mesoscopic physics, by implementing an electron-wave realization of a Fano interferometer using pairs of coupled quantum point contacts (QPCs). Within this scheme, the discrete level required for a Fano resonance is provided by pinching off one of the QPCs, thereby inducing the formation of a quasibound state at the center of its self-consistent potential barrier. Using this system, we demonstrate a form of nonequilibrium Fano resonance (NEFR), in which nonlinear electrical biasing of the interferometer gives rise to pronounced distortions of its Fano resonance. Our experimental results are captured well by a quantitative theoretical model, which considers a system in which a standard two-path Fano interferometer is coupled to an additional, intruder, continuum. According to this theory, the observed distortions in the Fano resonance arise only in the presence of coupling to the intruder, indicating that the NEFR provides a sensitive means to infer the presence of weak coupling between mesoscopic systems.

  15. Electrical Modulation of Fano Resonance in Plasmonic Nanostructures Using Graphene

    DEFF Research Database (Denmark)

    Emani, Naresh K.; Chung, Ting-Fung; Kildishev, Alexander V.;

    2014-01-01

    Pauli blocking of interband transistions gives rise to tunable optical properties in single layer graphene (SLG). This effect is exploited in a graphene-nanoantenna hybrid device where Fano resonant plasmonic nanostructures are fabricated on top of a graphene sheet. The use of Fano resonant......-element simulations. Our approach can be used for development of next generation of tunable plasmonic and hybrid nanophotonic devices....

  16. 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...

  17. Toroidal and magnetic Fano resonances in planar THz metamaterials

    Science.gov (United States)

    Han, Song; Gupta, Manoj; Cong, Longqing; Srivastava, Yogesh Kumar; Singh, Ranjan

    2017-09-01

    The toroidal dipole moment, a localized electromagnetic excitation of torus magnetic fields, has been observed experimentally in metamaterials. However, the metamaterial based toroidal moment was restricted at higher frequencies by the complex three-dimensional structure. Recently, it has been shown that toroidal moment could also be excited in a planar metamaterial structure. Here, we use asymmetric Fano resonators to illustrate theoretically and experimentally the underlying physics of the toroidal coupling in an array of planar metamaterials. It is observed that the anti-parallel magnetic moment configuration shows toroidal excitation with higher quality (Q) factor Fano resonance, while the parallel magnetic moment shows relatively lower Q factor resonance. Moreover, the electric and toroidal dipole interferes destructively to give rise to an anapole excitation. The magnetic dipole-dipole interaction is employed to understand the differences between the toroidal and magnetic Fano resonances. We further study the impact of intra unit-cell coupling between the Fano resonator pairs in the mirrored and non-mirrored arrangements. The numerical and theoretical approach for modelling the near-field effects and experimental demonstration of toroidal and magnetic Fano resonances in planar systems are particularly promising for tailoring the loss in metamaterials across a broad range of the electromagnetic spectrum.

  18. Tuning Fano resonances of graphene-based gratings

    Science.gov (United States)

    de Ceglia, Domenico; Vincenti, Maria A.; Grande, Marco; Bianco, Giuseppe Valerio; Bruno, Giovanni; D'Orazio, Antonella; Scalora, Michael

    2016-09-01

    We present a strategy to control Fano resonances in hybrid graphene-silicon-on-insulator gratings. The presence of a mono- or few-layer graphene film allows to electrically and/or chemically tuning the Fano resonances that result from the interaction of narrow-band, quasi-normal modes and broad-band, Fabry-Perot-like modes. Transmission, reflection and absorption spectra undergo significant modulations under the application of a static voltage to the graphene film. In particular, for low values of the graphene chemical potential, the structure exhibits a symmetric Lorentzian resonance; when the chemical potential increases beyond a specific threshold, the grating resonance becomes Fano-like, hence narrower and asymmetric. This transition occurs when the graphene optical response changes from that of a lossy dielectric medium into that of a low-loss metal. Further increasing the chemical potential allows to blue-shift the Fano resonance, leaving its shape and linewidth virtually unaltered. We provide a thorough description of the underlying physics by resorting to the quasi-normal mode description of the resonant grating and retrieve perturbative expressions for the characteristic wavelength and linewidth of the resonance. The roles of number of graphene layers, waveguide-film thickness and graphene quality on the tuning abilities of the grating will be discussed. Although developed for infrared telecom wavelengths and silicon-on-insulator technology, the proposed structure can be easily designed for other wavelengths, including visible, far-infrared and terahertz, and other photonic platforms.

  19. Acoustically induced transparency using Fano resonant periodic arrays

    KAUST Repository

    El-Amin, Mohamed

    2015-10-22

    A three-dimensional acoustic device, which supports Fano resonance and induced transparency in its response to an incident sound wave, is designed and fabricated. These effects are generated from the destructive interference of closely coupled one broad- and one narrow-band acoustic modes. The proposed design ensures excitation and interference of two spectrally close modes by locating a small pipe inside a wider and longer one. Indeed, numerical simulations and experiments demonstrate that this simple-to-fabricate structure can be used to generate Fano resonance as well as acoustically induced transparency with promising applications in sensing, cloaking, and imaging.

  20. Fano-like resonances in strongly coupled binary Coulomb systems

    CERN Document Server

    Silvestri, Luciano; Donko, Zoltan; Hartmann, Peter; Kaehlert, Hanno

    2014-01-01

    Molecular dynamics (MD) simulations of a strongly coupled binary ionic mixture have shown the presence of a sharp minimum in the dynamical density fluctuation spectrum. This phenomenon is reminiscent of the well known Fano anti-resonance, occurring in various physical processes. We give a theoretical analysis using the Quasi Localized Charge Approximation, pointing out that the observed phenomenon in the equilibrium spectrum is the consequence, induced by the Fluctuation-Dissipation Theorem, of the Fano anti-resonance, whose existence in the system is verified by further MD simulation.

  1. Experimental demonstration of sharp Fano resonance in optical metamaterials composed of asymmetric double bars.

    Science.gov (United States)

    Moritake, Yuto; Kanamori, Yoshiaki; Hane, Kazuhiro

    2014-07-01

    We experimentally demonstrated Fano resonance in metamaterials composed of asymmetric double bars (ADBs) in the optical region. ADB metamaterials were fabricated by a lift-off method, and the optical spectra were measured. Around a wavelength of 1100 nm, measured optical spectra clearly showed sharp Fano resonance due to weak asymmetry of the ADB structures. The highest-quality factor (Q-factor) of the Fano resonance was 7.34. Calculated spectra showed the same tendency as the experimental spectra. Moreover, in a Fano resonant condition, out of phase of induced current flowing along each bar was revealed by electromagnetic field calculations. These antiphase currents decreased radiative loss of the Fano mode, resulting in a high Q-factor of the Fano resonance in ADB metamaterials. As the degree of asymmetry became small, the Q-factor decreased, and the Fano resonance disappeared because the effect of Joule loss became significant.

  2. Fano resonances in antennas: General control over radiation patterns

    CERN Document Server

    Rybin, Mikhail V; Filonov, Dmitry S; Slobozhanyuk, Alexey P; Belov, Pavel A; Kivshar, Yuri S; Limonov, Mikhail F

    2013-01-01

    The concepts of many optical devices are based on the fundamental physical phenomena such as resonances. One of the commonly used devices is an electromagnetic antenna that converts localized energy into freely propagating radiation and vise versa, offering unique capabilities for controlling electromagnetic radiation. Here we propose a concept for controlling the intensity and directionality of electromagnetic wave scattering in radio-frequency and optical antennas based on the physics of Fano resonances. We develop an analytical theory of spatial Fano resonances in antennas that describes switching of the radiation pattern between the forward and backward directions, and confirm our theory with both numerical calculations and microwave experiments. Our approach bridges the concepts of conventional radio antennas and photonic nanoantennas, and it provides a paradigm for the design of wireless optical devices with various functionalities and architectures.

  3. Optically tunable Fano resonance in a grating-based Fabry-Perot cavity-coupled microring resonator on a silicon chip.

    Science.gov (United States)

    Zhang, Weifeng; Li, Wangzhe; Yao, Jianping

    2016-06-01

    A grating-based Fabry-Perot (FP) cavity-coupled microring resonator on a silicon chip is reported to demonstrate an all-optically tunable Fano resonance. In the device, an add-drop microring resonator (MRR) is employed, and one of the two bus waveguides is replaced by an FP cavity consisting of two sidewall Bragg gratings. By choosing the parameters of the gratings, the resonant mode of the FP cavity is coupled to one of the resonant modes of the MRR. Due to the coupling between the resonant modes, a Fano resonance with an asymmetric line shape resulted. Measurement results show a Fano resonance with an extinction ratio of 22.54 dB, and a slope rate of 250.4 dB/nm is achieved. A further study of the effect of the coupling on the Fano resonance is performed numerically and experimentally. Thanks to the strong light-confinement capacity of the MRR and the FP cavity, a strong two-photon absorption induced nonlinear thermal-optic effect resulted, which is used to tune the Fano resonance optically.

  4. Semiconductor-metal nanoparticle molecules: hybrid excitons and the nonlinear fano effect.

    Science.gov (United States)

    Zhang, Wei; Govorov, Alexander O; Bryant, Garnett W

    2006-10-06

    Modern nanotechnology opens the possibility of combining nanocrystals of various materials with very different characteristics in one superstructure. Here we study theoretically the optical properties of hybrid molecules composed of semiconductor and metal nanoparticles. Excitons and plasmons in such a hybrid molecule become strongly coupled and demonstrate novel properties. At low incident light intensity, the exciton peak in the absorption spectrum is broadened and shifted due to incoherent and coherent interactions between metal and semiconductor nanoparticles. At high light intensity, the absorption spectrum demonstrates a surprising, strongly asymmetric shape. This shape originates from the coherent internanoparticle Coulomb interaction and can be viewed as a nonlinear Fano effect which is quite different from the usual linear Fano resonance.

  5. Circular dichroism induced by Fano resonances in planar chiral oligomers

    CERN Document Server

    Hopkins, Ben; Miroshnichenko, Andrey E; Kivshar, Yuri S

    2016-01-01

    We present a general theory of circular dichroism induced in planar chiral nanostructures with rotational symmetry. It is demonstrated, analytically, that the handedness of the incident field's polarization can control whether a nanostructure induces either absorption or scattering losses, even when the total loss (extinction) is polarization-independent. We then show that this effect is a consequence of modal interference so that strong circular dichroism in absorption and scattering can be engineered by combining Fano resonances with chiral nanoparticle clusters.

  6. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

    This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...

  7. Light-tunable Fano resonance in metal-dielectric multilayer structures

    Science.gov (United States)

    Hayashi, S.; Nesterenko, D. V.; Rahmouni, A.; Ishitobi, H.; Inouye, Y.; Kawata, S.; Sekkat, Z.

    2016-01-01

    High-Q optical Fano resonances realized in a variety of plasmonic nanostructures and metamaterials are very much promising for the development of new potent photonic devices, such as optical sensors and switches. One of the key issues in the development is to establish ways to effectively modulate the Fano resonance by external perturbations. Dynamic tuning of the Fano resonance applying the mechanical stress and electric fields has already been demonstrated. Here, we demonstrate another way of tuning, i.e., photo-tuning of the Fano resonance. We use a simple metal-dielectric multilayer structure that exhibits a sharp Fano resonance originating from coupling between a surface plasmon polariton mode and a planar waveguide mode. Using a dielectric waveguide doped with azo dye molecules that undergo photoisomerization, we succeeded in shifting the Fano resonance thorough photo-modulation of the propagation constant of the waveguide mode. The present work demonstrates the feasibility of photo-tuning of the Fano resonance and opens a new avenue towards potential applications of the Fano resonance. PMID:27623741

  8. Fano Resonance in Landau Fermi and Luttinger Liquids

    Institute of Scientific and Technical Information of China (English)

    HAN Yue-Wu; LIU Yu-Liang; CAI Shao-Hong

    2007-01-01

    With a two-channel model,we study the influence of temperature,external voltage and magnetic flux on the line shape of the Fano resonance,and show that in the Luttinger liquid cace,the background transmittance and the asymmetric parameter depend strongly on the temperature and external voltage,while for the Landav Fermi liquid case they are nearly independent of these parameters in the low energy region.Moreover,we demonstrate that the asymmetric parameter changes periodically with an external magnetic flux,which is consictont with the recent experimental data.

  9. Electrically tunable Fano-type resonance of an asymmetric metal wire pair.

    Science.gov (United States)

    Fu, Quanhong; Zhang, Fuli; Fan, Yuancheng; He, Xuan; Qiao, Tong; Kong, Botao

    2016-05-30

    We theoretically and experimentally investigate the electrically tunable Fano-type resonance of asymmetric metal wire pair loaded with varactor diodes. It is illustrated that Fano-type transmission spectrum with high quality factor Q appears as a result of interference between the dipole and quadrupole modes. The ohmic loss of series resistance in varactor diode makes major contribution to absorption. At the Fano-type resonance frequency, both the two metal wires exhibit the strongest electric resonance simultaneously, and the Fano-type resonance manifests a large group delay. As the bias voltage ranges from 0 V to 8 V, the Fano-type resonance frequency exhibits a prominent blueshift of 0.16 GHz and the transmission experiences a modulation with a modulation depth of 97%.

  10. Fano resonance engineering in slanted cavities with hyperbolic metamaterials

    Science.gov (United States)

    Vaianella, Fabio; Maes, Bjorn

    2016-09-01

    We present the possibility to engineer Fano resonances using multilayered hyperbolic metamaterials. The proposed cavity designs are composed of multilayers with a central slanted part. The highly tunable resonances originate from the interference between a propagating and an evanescent mode inside the slanted section. The propagating mode can reach an extremely high effective index, making the realization of deeply subwavelength cavities possible, as small as 5 nm. The evanescent mode is rarely analyzed but plays an important role here, as its contribution determines the particular shape of the cavity characteristic. Moreover, these phenomena cannot be described using effective medium theory, and we provide a more rigorous analysis. The reported resonances are very sensitive to any structural changes and could be used for sensing applications.

  11. Refractive Index Sensor Based on Fano Resonances in Metal-Insulator-Metal Waveguides Coupled with Resonators

    Directory of Open Access Journals (Sweden)

    Yue Tang

    2017-04-01

    Full Text Available A surface plasmon polariton refractive index sensor based on Fano resonances in metal–insulator–metal (MIM waveguides coupled with rectangular and ring resonators is proposed and numerically investigated using a finite element method. Fano resonances are observed in the transmission spectra, which result from the coupling between the narrow-band spectral response in the ring resonator and the broadband spectral response in the rectangular resonator. Results are analyzed using coupled-mode theory based on transmission line theory. The coupled mode theory is employed to explain the Fano resonance effect, and the analytical result is in good agreement with the simulation result. The results show that with an increase in the refractive index of the fill dielectric material in the slot of the system, the Fano resonance peak exhibits a remarkable red shift, and the highest value of sensitivity (S is 1125 nm/RIU, RIU means refractive index unit. Furthermore, the coupled MIM waveguide structure can be integrated with other photonic devices at the chip scale. The results can provide a guide for future applications of this structure.

  12. Fano resonance and wave transmission through a chain structure with an isolated ring composed of defects

    Institute of Scientific and Technical Information of China (English)

    Zhang Cun-Xi; Ding Xiu-Huan; Wang Rui; Zhou Yun-Qing; Kong Ling-Min

    2012-01-01

    We consider a discrete model that describes a linear chain of particles coupled to an isolated ring composed of N defects.This simple system can be regarded as a generalization of the familiar Fano-Anderson model.It can be used to model discrete networks of coupled defect modes in photonic crystals and simple waveguide arrays in two-dimensional lattices.The analytical result of the transmission coefficient is obtained,along with the conditions for perfect reflections and transmissions due to either destructive or constructive interferences.Using a simple example,we further investigate the relationship between the resonant frequencies and the number of defects N,and study how to affect the numbers of perfect reflections and transmissions.In addition,we demonstrate how these resonance transmissions and refections can be tuned by one nonlinear defect of the network that possesses a nonlinear Kerr-like response.

  13. Composite modulation of Fano resonance in plasmonic microstructures by electric-field and microcavity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan; Wu, Chenyun; Yang, Hong [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China); Hu, Xiaoyong, E-mail: xiaoyonghu@pku.edu.cn; Gong, Qihuang [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100871 (China)

    2014-11-03

    Composite modulation of Fano resonance by using electric-field and microcavity simultaneously is realized in a plasmonic microstructure, which consists of a gold nanowire grating inserted into a Fabry-Perot microcavity composited of a liquid crystal layer sandwiched between two indium tin oxide layers. The Fano resonance wavelength varies with the applied voltage and the microcavity resonance. A large shift of 48 nm in the Fano resonance wavelength is achieved when the applied voltage is 20 V. This may provide a new way for the study of multi-functional integrated photonic circuits and chips based on plasmonic microstructures.

  14. Fano resonance control in a photonic crystal structure and its application to ultrafast switching

    CERN Document Server

    Yu, Yi; Hu, Hao; Xue, Weiqi; Peucheret, Christophe; Chen, Yaohui; Oxenløwe, Leif Katsuo; Yvind, Kresten; Mørk, Jesper

    2014-01-01

    Fano resonances appear in quantum mechanical as well as classical systems as a result of the interference between two paths: one involving a discrete resonance and the other a continuum. Compared to a conventional resonance, characterized by a Lorentzian spectral response, the characteristic asymmetric and sharp spectral response of a Fano resonance is suggested to enable photonic switches and sensors with superior characteristics. While experimental demonstrations of the appearance of Fano resonances have been made in both plasmonic and photonic-crystal structures, the control of these resonances is experimentally challenging, often involving the coupling of near-resonant cavities. Here, we experimentally demonstrate two simple structures that allow surprisingly robust control of the Fano spectrum. One structure relies on controlling the amplitude of one of the paths and the other uses symmetry breaking. Short-pulse dynamic measurements show that besides drastically increasing the switching contrast, the tra...

  15. Fano resonance control in a photonic crystal structure and its application to ultrafast switching

    DEFF Research Database (Denmark)

    Yu, Yi; Heuck, Mikkel; Hu, Hao;

    2014-01-01

    We experimentally demonstrate a photonic crystal structure that allows easy and robust control of the Fano spectrum. Its operation relies on controlling the amplitude of light propagating along one of the light paths in the structure from which the Fano resonance is obtained. Short-pulse dynamic...

  16. Coulomb-Modified Fano Resonance in a One-Lead Quantum Dot

    DEFF Research Database (Denmark)

    Johnson, Anna Ansaba; M. Marcus, C.; Hanson, Mats

    2003-01-01

    We investigate a tunable Fano interferometer consisting of a quantum dot coupled via tunneling to a one-dimensional channel. In addition to Fano resonance, the channel shows strong Coulomb response to the dot, with a single electron modulating channel conductance by factors of up to 100. Where...

  17. Realizing of plasmon Fano resonance with a metal nanowall moving along MIM waveguide

    Science.gov (United States)

    Chen, Fang; Yao, Duanzheng

    2016-06-01

    A larger number of complicated plasmonic nanostructures have been realized to exhibit Fano interference. In this paper, we demonstrate a simple nanostructure, side coupled waveguide resonator system with a metal nanowall located in the metal-insulator-metal waveguide (MIM), which can also achieve multiple plasmonic Fano resonance. In the proposed nanostructure, the asymmetric line shape originates from the interference between the slot resonator and the new resonator. Therefore, the Fano line shape can be actively controlled by the phase difference of the two resonators and the thickness of the metal nanowall. A scattering matrix method is used to calculate the transmission spectra. Results obtained by the scattering matrix theory are consistent with those from the finite-difference time-domain simulations (FDTD). Moreover, Fano resonances in the proposed structure show high sensitivity, which may have important application in plasmonic nanosensor and modulator.

  18. Fano-like interference of plasmon resonances at a single rod-shaped nanoantenna

    OpenAIRE

    López-Tejeira, F.; Paniagua-Domínguez, R.; Rodríguez-Oliveros, R.; Sánchez-Gil, J. A.

    2011-01-01

    Single metallic nanorods acting as half-wave antennas in the optical range exhibit an asymmetric, multi-resonant scattering spectrum that strongly depends on both their length and dielectric properties. Here we show that such spectral features can be easily understood in terms of Fano-like interference between adjacent plasmon resonances. On the basis of analytical and numerical results for different geometries, we demonstrate that Fano resonances may appear for such single-particle nanoanten...

  19. Ghost Fano Resonance of Excitons in Twisted Bilayer Graphene

    Science.gov (United States)

    Liang, Yufeng

    2014-03-01

    Metallic systems are generally considered to be unable to harbor tightly bound excitons because of the strong screening effect as well as the absence of a finite band gap. Previously, exception has only been found in one-dimensional metallic carbon nanotubes due to the depressed screening effects and the symmetry gap. We explore the exciton spectra of twisted bilayer graphene (tBLG) and predict the existence of even more strongly bound exciton (with binding energy as large as 0.5eV) in this system despite of its higher dimensionality. Based on our results from first-principles simulations and effective model calculations, a mechanism known as the ghost Fano resonance is proposed for the bound exciton formation in metallic systems beyond the dimensonality-related argument. Our results shed light on engineering the e-h excitations in the few-layer van der Waals heterojunction. NSF Grant No. DMR-1207141.

  20. Enhancing narrowband high order harmonic generation by Fano resonances

    CERN Document Server

    Rothhardt, Jan; Demmler, Stefan; Krebs, Manuel; Fritzsche, Stephan; Limpert, Jens; Tünnermann, Andreas

    2014-01-01

    Resonances in the photo-absorption spectrum of the generating medium can modify the spectrum of high order harmonics. In particular, window-type Fano resonances can reduce photo-absorption within a narrow spectral region and, consequently, lead to an enhanced emission of high-order harmonics in absorption-limited generation conditions. For high harmonic generation in argon it is shown that the 3s3p6 np 1P1 window resonances (n=4,5,6) give rise to enhanced photon yield. In particular, the 3s3p6 4p 1P1 resonance at 26.6 eV allows a relative enhancement up to a factor of 30 compared to the characteristic photon emission of the neighboring harmonic order. This enhanced, spectrally isolated and coherent photon emission line has a relative energy bandwidth of only {\\Delta}E/E=3*10-3. Therefore, it might be directly applied for precision spectroscopy or coherent diffractive imaging without the need of additional spectral filtering. The presented mechanism can be employed for tailoring and controlling the high harmon...

  1. Coil-type Fano Resonances: a Plasmonic Approach to Magnetic Sub-diffraction Confinement

    KAUST Repository

    Panaro, Simone

    2015-05-10

    Matrices of nanodisk trimers are introduced as plasmonic platforms for the generation of localized magnetic hot-spots. In Fano resonance condition, the optical magnetic fields can be squeezed in sub-wavelength regions, opening promising scenarios for spintronics.

  2. Gain enhanced Fano resonance in a coupled photonic crystal cavity-waveguide structure

    Science.gov (United States)

    Zhao, Yanhui; Qian, Chenjiang; Qiu, Kangsheng; Tang, Jing; Sun, Yue; Jin, Kuijuan; Xu, Xiulai

    2016-01-01

    Systems with coupled cavities and waveguides have been demonstrated as optical switches and optical sensors. To optimize the functionalities of these optical devices, Fano resonance with asymmetric and steep spectral line shape has been used. We theoretically propose a coupled photonic crystal cavity-waveguide structure to achieve Fano resonance by placing partially reflecting elements in waveguide. To enhance Fano resonance, optical gain material is introduced into the cavity. As the gain increases, the transmission line shape becomes steepened and the transmissivity can be six times enhanced, giving a large contrast by a small frequency shift. It is prospected that the gain enhanced Fano resonance is very useful for optical switches and optical sensors. PMID:27640809

  3. Emission wavelength tuning of fluorescence by fine structural control of optical metamaterials with Fano resonance

    Science.gov (United States)

    Moritake, Y.; Kanamori, Y.; Hane, K.

    2016-09-01

    We demonstrated fine emission wavelength tuning of quantum dot (QD) fluorescence by fine structural control of optical metamaterials with Fano resonance. An asymmetric-double-bar (ADB), which was composed of only two bars with slightly different bar lengths, was used to obtain Fano resonance in the optical region. By changing the short bar length of ADB structures with high dimensional accuracy in the order of 10 nm, resonant wavelengths of Fano resonance were controlled from 1296 to 1416 nm. Fluorescence of QDs embedded in a polymer layer on ADB metamaterials were modified due to coupling to Fano resonance and fine tuning from 1350 to 1376 nm was observed. Wavelength tuning of modified fluorescence was reproduced by analysis using absorption peaks of Fano resonance. Tuning range of modified fluorescence became narrow, which was interpreted by a simple Gaussian model and resulted from comparable FWHM in QD fluorescence and Fano resonant peaks. The results will help the design and fabrication of metamaterial devices with fluorophores such as light sources and biomarkers.

  4. Emission wavelength tuning of fluorescence by fine structural control of optical metamaterials with Fano resonance.

    Science.gov (United States)

    Moritake, Y; Kanamori, Y; Hane, K

    2016-09-13

    We demonstrated fine emission wavelength tuning of quantum dot (QD) fluorescence by fine structural control of optical metamaterials with Fano resonance. An asymmetric-double-bar (ADB), which was composed of only two bars with slightly different bar lengths, was used to obtain Fano resonance in the optical region. By changing the short bar length of ADB structures with high dimensional accuracy in the order of 10 nm, resonant wavelengths of Fano resonance were controlled from 1296 to 1416 nm. Fluorescence of QDs embedded in a polymer layer on ADB metamaterials were modified due to coupling to Fano resonance and fine tuning from 1350 to 1376 nm was observed. Wavelength tuning of modified fluorescence was reproduced by analysis using absorption peaks of Fano resonance. Tuning range of modified fluorescence became narrow, which was interpreted by a simple Gaussian model and resulted from comparable FWHM in QD fluorescence and Fano resonant peaks. The results will help the design and fabrication of metamaterial devices with fluorophores such as light sources and biomarkers.

  5. Fano Resonance in an Electrically Driven Plasmonic Device

    Science.gov (United States)

    Vardi, Yuval; Cohen-Hoshen, Eyal; Shalem, Guy; Bar-Joseph, Israel

    Electrically driven plasmonic devices offer unique opportunities as a research tool and for practical applications. In such devices, current that flows across a metallic tunnel junction excites a plasmon, which gives rise to light emission. This local nature of the excitation allows access into ''dark'' modes, which are not easily excited by far field illumination. We present an electrically driven plasmonic device, based on a gold nanoparticle single-electron-transistor, and investigate the light emission due to the tunneling current. The applied voltage determines the emitted spectral lineshape, enables an excellent control of the plasmonic spectrum. We show that the use of this structure allows us to characterize the electrical properties of the two tunnel barriers, and determine their role in the light emission process. Furthermore, we find a Fano resonance, resulting from interference between the nanoparticle and electrodes dipoles. This resonance is seen due to the local nature of the excitation, and is manifested as a sharp asymmetrical spectral dip. We show that the spectral position of this resonance can be conveniently controlled by the design of the structural parameters. Such devices may be a step toward the realization of an on-chip nano-optical emitters and sensors.

  6. Mechanism of the Fano resonance in a planar metamaterials: Analysis from the coupled two-oscillator model

    CERN Document Server

    Song, Song-Kum

    2016-01-01

    Mechanism of the Fano resonances in planar metamaterials demonstrate based on the coupled two-oscillator model. We have described the optical spectrums like reflectance and transmittance near the resonances of bright mode (continuum mode) and dark mode (discrete mode) and explained their optical properties by the Fano formulism. the Fano formulism of the resonances in the planar metamaterials can predict the asymmetric shape line and radiative properties occurring in reflectance and transmittance from the coupling between bright and dark modes.

  7. Geometrically Protected Resonance Modes and Optical Fano Resonances

    CERN Document Server

    Regan, Emma C; Lopez, Josue J; Hsu, Chia Wei; Zhen, Bo; Joannopoulos, John D; Soljacic, Marin

    2015-01-01

    Traditionally, photonic crystal slabs can support resonances that are strongly confined to the slab but also couple to external radiation. However, when a photonic crystal slab is placed on a substrate, the resonance modes become less confined, and as the index contrast between slab and substrate decreases, they eventually disappear. Using the scale structure of the Dione Juno butterfly wing as an inspiration, we present a low-index zigzag surface structure that supports resonance modes even without index contrast with the substrate. The zigzag structure supports resonances that are contained away from the substrate; this geometrically protects the modes from coupling to the substrate. We experimentally verify the protected resonance property of the zigzag structure in the visible wavelength regime. Potential applications include substrate-independent structural color and light guiding.

  8. Fano line shape and phase reversal in a split-ring resonator based metamaterial

    Science.gov (United States)

    Wallauer, J.; Walther, M.

    2013-11-01

    We introduce a universal scheme for invoking a full line shape and phase reversal of Fano resonances in plasmonic metamaterials. The effect is based on opening a new excitation channel through minor structural displacements which enable continuous tunability. At the example of a metamaterial designed for terahertz frequencies, consisting of two coupled split-ring resonators, it is demonstrated by simulation and experiment that displacements by only a fraction of the wavelength are sufficient to invoke a full line shape reversal, in combination with the change from inducing a phase delay to a phase advance for a transmitted wave. Our approach provides unprecedented control of Fano asymmetry and phase, potentially enabling the implementation of dynamically tuneable Fano metamaterials and Fano-plasmonic devices such as dynamic filters or phase shifters.

  9. Percolation in photonic crystals revealed by Fano Resonance

    CERN Document Server

    Pariente, Jose Angel; Pecharomán, Carlos; Blanco, Alvaro; García-Martín, Antonio; López, Cefe

    2016-01-01

    The understanding of how the arrangement of defects in photonic crystals impacts its photonic properties is cru-cial for the design of functional materials based thereon. By preparing photonic crystals with random missing scatterers we create crystals where disorder is embodied as vacancies in an otherwise perfect lattice rather than the usual positional or size disorder. We show that the amount of defects not only determines the intensity but also the nature of the light scattering. As the amount of defects varies, light scattering undergoes a transition whereby the usual signatures of photonic gaps (Bragg peak) suffer line-shape changes (Bragg dip) that can be readily described with the Fano resonance q parameter. When the amount of vacancies reaches the percolation threshold, q undergoes a sign change signaling the transition from a crystal to a mosaic of microcrystals through a state where scattering is maximum. Beyond that point the system reenters a state of low scattering that ap-pears in the guise of ...

  10. Electron Transport Through a Quantum Wire with a Side-Coupled Quantum Dot:Fano Resonance

    Institute of Scientific and Technical Information of China (English)

    熊永建; 贺舟波

    2004-01-01

    The Fano resonance of a quantum wire (QW) with a side-coupled quantum dot (QD) is investigated. The QD has multilevel and is in the Coulomb blockade regime. We show that there are two aspects in contribution to asymmetric Fano dip line shape of conductance: (1) the quantum interference between the resonant level and non-resonant levels, (2) the asymmetric electron occupation of levels in the two sides of a resonant level in the QD. The smearing of the asymmetry of the dip structure with the increasing temperature is partially attributed to fluctuation of electron state in the QD.

  11. Fano-like interference of plasmon resonances at a single rod-shaped nanoantenna

    CERN Document Server

    López-Tejeira, F; Rodríguez-Oliveros, R; Sánchez-Gil, J A

    2011-01-01

    Single metallic nanorods acting as half-wave antennas in the optical range exhibit an asymmetric, multi-resonant scattering spectrum that strongly depends on both their length and dielectric properties. Here we show that such spectral features can be easily understood in terms of Fano-like interference between adjacent plasmon resonances. On the basis of analytical and numerical results for different geometries, we demonstrate that Fano resonances may appear for such single-particle nanoantennas provided that interacting resonances overlap in both spatial and frequency domains.

  12. Unconventional Fano effect and off-resonance field enhancement in plasmonic coated spheres

    CERN Document Server

    Arruda, Tiago J; Pinheiro, Felipe A

    2013-01-01

    We investigate light scattering by coated spheres composed of a dispersive plasmonic core and a dielectric shell. By writing the absorption cross-section in terms of the internal electromagnetic fields, we demonstrate it is an observable sensitive to interferences that ultimately lead to the Fano effect. Specially, we show that unconventional Fano resonances, recently discovered for homogeneous spheres with large dielectric permittivities, can also occur for metallic spheres coated with single dielectric layers. These resonances arise from the interference between two electromagnetic modes with the same multipole moment inside the shell and not from interactions between various plasmon modes of different layers of the particle. In contrast to the case of homogeneous spheres, unconventional Fano resonances in coated spheres exist even in the Rayleigh limit. These resonances can induce an off-resonance field enhancement, which is approximately one order of magnitude larger than the one achieved with conventiona...

  13. Fano resonances control and slow light with Bose-Einstein Condensate in a cavity setup

    CERN Document Server

    Akram, M Javed; Khan, M Miskeen; Saif, Farhan

    2015-01-01

    We theoretically investigate the probe field transmission in an optomechanical cavity setup with Bose-Einstein Condensate (BEC), where the standing wave that forms in the cavity results in an one-dimensional optical lattice potential. We report that in the presence of atom-atom interactions, the coupling of the cavity field with condensate (Bogoliubov mode), the cavity field fluctuations and the condensate fluctuations leads to the emergence of the tunable Fano resonances in the probe absorption spectrum. Within the experimental reach, based on analytical and numerical simulations, we find that the optomechanical system with BEC provides great flexibility to tune the Fano resonances, as the width of the resonance is controllable by the coupling field and additionally, with the atom-atom interaction. Moreover, Fano resonances are analyzed for the fluctuations of the cavity field and the fluctuations of the condensate with finite atomic two-body interaction, which shows an excellent compatibility with the origi...

  14. Near-infrared linewidth narrowing in plasmonic Fano-resonant metamaterials via tuning of multipole contributions

    Science.gov (United States)

    Lim, Wen Xiang; Han, Song; Gupta, Manoj; MacDonald, Kevin F.; Singh, Ranjan

    2017-08-01

    We report on an experimental and computational (multipole decomposition) study of Fano resonance modes in complementary near-IR plasmonic metamaterials. Resonance wavelengths and linewidths can be controlled by changing the symmetry of the unit cell so as to manipulate the balance among multipole contributions. In the present case, geometrically inverting one half of a four-slot (paired asymmetric double bar) unit cell design changes the relative magnitude of magnetic quadrupole and toroidal dipole contributions leading to the enhanced quality factor, figure of merit, and spectral tuning of the plasmonic Fano resonance.

  15. Experimental demonstration of non-reciprocal transmission in a nonlinear photonic-crystal Fano structure

    DEFF Research Database (Denmark)

    Yu, Yi; Chen, Yaohui; Hu, Hao;

    2015-01-01

    We suggest and experimentally demonstrate a photonic-crystal structure with more than 30 dB difference between forward and backward transmission levels. The non-reciprocity relies on the combination of ultrafast carrier nonlinearities and spatial symmetry breaking in a Fano structure employing...

  16. Sensing Based on Fano-Type Resonance Response of All-Dielectric Metamaterials

    Directory of Open Access Journals (Sweden)

    Elena Semouchkina

    2015-04-01

    Full Text Available A new sensing approach utilizing Mie resonances in metamaterial arrays composed of dielectric resonators is proposed. These arrays were found to exhibit specific, extremely high-Q factor (up to 15,000 resonances at frequencies corresponding to the lower edge of the array second transmission band. The observed resonances possessed with features typical for Fano resonances (FRs, which were initially revealed in atomic processes and recently detected in macro-structures, where they resulted from interference between local resonances and a continuum of background waves. Our studies demonstrate that frequencies and strength of Fano-type resonances in all-dielectric arrays are defined by interaction between local Mie resonances and Fabry-Perot oscillations of Bloch eigenmodes that makes possible controlling the resonance responses by changing array arrangements. The opportunity for obtaining high-Q responses in compact arrays is investigated and promising designs for sensing the dielectric properties of analytes in the ambient are proposed.

  17. Controlled Electromagnetically Induced Transparency and Fano Resonances in Hybrid BEC-Optomechanics

    CERN Document Server

    Yasir, Kashif Ammar

    2015-01-01

    We investigate the controllability of electromagnetically induced transparency (EIT) and Fano resonances in hybrid optomechanical system which is composed of cigar-shaped Bose-Einstein condensate (BEC) trapped inside high-finesse Fabry-P\\'erot cavity driven by a single mode optical field along the cavity axis and a transverse pump field. Here, transverse optical field is used to control the phenomenon of EIT in the output probe laser field. The output probe laser field can efficiently be amplified or attenuated depending on the strength of transverse optical field. Furthermore, we demonstrate the existence of Fano resonances in the output field spectra and discuss the controlled behavior of Fano resonances using transverse optical field. To observe this phenomena in laboratory, we suggest a certain set of experimental parameters.

  18. Highly Sensitive Aluminum-Based Biosensors using Tailorable Fano Resonances in Capped Nanostructures

    Science.gov (United States)

    Lee, Kuang-Li; Hsu, Hsuan-Yeh; You, Meng-Lin; Chang, Chia-Chun; Pan, Ming-Yang; Shi, Xu; Ueno, Kosei; Misawa, Hiroaki; Wei, Pei-Kuen

    2017-03-01

    Metallic nanostructure-based surface plasmon sensors are capable of real-time, label-free, and multiplexed detections for chemical and biomedical applications. Recently, the studies of aluminum-based biosensors have attracted a large attention because aluminum is a more cost-effective metal and relatively stable. However, the intrinsic properties of aluminum, having a large imaginary part of the dielectric function and a longer evanescent length, limit its sensing capability. Here we show that capped aluminum nanoslits fabricated on plastic films using hot embossing lithography can provide tailorable Fano resonances. Changing height of nanostructures and deposited metal film thickness modulated the transmission spectrum, which varied from Wood’s anomaly-dominant resonance, asymmetric Fano profile to surface plasmon-dominant resonance. For biolayer detections, the maximum surface sensitivity occurred at the dip of asymmetric Fano profile. The optimal Fano factor was close to ‑1.3. The wavelength and intensity sensitivities for surface thickness were up to 2.58 nm/nm and 90%/nm, respectively. The limit of detection (LOD) of thickness reached 0.018 nm. We attributed the enhanced surface sensitivity for capped aluminum nanoslits to a reduced evanescent length and sharp slope of the asymmetric Fano profile. The protein-protein interaction experiments verified the high sensitivity of capped nanostructures. The LOD was down to 236 fg/mL.

  19. Heat Generation by Electrical Current in Quantum Dot System with Fano Resonance

    Institute of Scientific and Technical Information of China (English)

    陈桥; 许迈昌; 屈喜龙

    2012-01-01

    We study the heat generation in quantum dot system with Fano resonance by nonequilibrium Green's functions method. The Fano resonance influences the heat generation significantly. As increases, the heat generation decreases gradually. From the study of Q-eV curves, we llnd that the linewidth function F has huge influence on the heat generation. The Q-eV curves display obvious steps when the linewidth function is small. However, these steps disappear with F increasing. As the source-drain bias eV increases, the Q-eVg curves also display interesting behaviors.

  20. Tailored Fano resonance and localized electromagnetic field enhancement in Ag gratings

    Science.gov (United States)

    Li, Zhaozhu; Klopf, J. Michael; Wang, Lei; Yang, Kaida; Lukaszew, Rosa A.

    2017-01-01

    Metallic gratings can support Fano resonances when illuminated with EM radiation, and their characteristic reflectivity versus incident angle lineshape can be greatly affected by the surrounding dielectric environment and the grating geometry. By using conformal oblique incidence thin film deposition onto an optical grating substrate, it is possible to increase the grating amplitude due to shadowing effects, thereby enabling tailoring of the damping processes and electromagnetic field couplings of the Fano resonances, hence optimizing the associated localized electric field intensity. To investigate these effects we compare the optical reflectivity under resonance excitation in samples prepared by oblique angle deposition (OAD) and under normal deposition (ND) onto the same patterned surfaces. We observe that by applying OAD method, the sample exhibits a deeper and narrower reflectivity dip at resonance than that obtained under ND. This can be explained in terms of a lower damping of Fano resonance on obliquely deposited sample and leads to a stronger localized electric field. This approach opens a fabrication path for applications where tailoring the electromagnetic field induced by Fano resonance can improve the figure of merit of specific device characteristics, e.g. quantum efficiency (QE) in grating-based metallic photocathodes. PMID:28290545

  1. Fano resonance assisting plasmonic circular dichroism from nanorice heterodimers for extrinsic chirality

    CERN Document Server

    Hu, Li; Fang, Liang; Chen, Guo; Wei, Hua; Fang, Yurui

    2015-01-01

    In this work, the circular dichroisms (CD) of nanorice heterodimers consisting of two parallel arranged nanorices with the same size but different materials are investigated theoretically. Symmetry-breaking is introduced by using different materials and oblique incidence to achieve strong CD at the vicinity of Fano resonance peaks. We demonstrate that all Au-Ag heterodimers exhibit multipolar Fano resonances and strong CD effect. A simple quantitative analysis shows that the structure with larger Fano asymmetry factor has stronger CD. The intensity and peak positions of the CD effect can be flexibly tuned in a large range by changing particle size, shape, the inter-particle distance and surroundings. Furthermore, CD spectra exhibit high sensitivity to ambient medium in visible and near infrared regions. Our results here are beneficial for the design and application of high sensitive CD sensors and other related fields.

  2. Manipulating Fano resonance via fs-laser melting of hybrid oligomers at nanoscale

    Science.gov (United States)

    Lepeshov, S. I.; Zuev, D. A.; Makarov, S. V.; Milichko, V. A.; Mukhin, I. S.; Krasnok, A. E.; Belov, P. A.

    2016-08-01

    Here, the novel concept of asymmetric metal-dielectric (hybrid) nanoparticles is proposed. The experimental data and the results of numerical simulation of the optical properties of hybrid nanostructures are presented. The change of their optical response after fs- laser modification is shown. The possibility of manipulating Fano resonance in hybrid oligomers by the gold nanoparticles reshaping is demonstrated.

  3. Control of Fano resonances and slow light using Bose-Einstein condensates in a nanocavity

    Science.gov (United States)

    Akram, M. Javed; Ghafoor, Fazal; Khan, M. Miskeen; Saif, Farhan

    2017-02-01

    In this study, a standing wave in an optical nanocavity with Bose-Einstein condensate (BEC) constitutes a one-dimensional optical lattice potential in the presence of a finite two bodies atomic interaction. We report that the interaction of a BEC with a standing field in an optical cavity coherently evolves to exhibit Fano resonances in the output field at the probe frequency. The behavior of the reported resonance shows an excellent compatibility with the original formulation of asymmetric resonance as discovered by Fano [U. Fano, Phys. Rev. 124, 1866 (1961), 10.1103/PhysRev.124.1866]. Based on our analytical and numerical results, we find that the Fano resonances and subsequently electromagnetically induced transparency of the probe pulse can be controlled through the intensity of the cavity standing wave field and the strength of the atom-atom interaction in the BEC. In addition, enhancement of the slow light effect by the strength of the atom-atom interaction and its robustness against the condensate fluctuations are realizable using presently available technology.

  4. Aharonov-Bohm Oscillations and Fano Resonance of a Coupled Dot-Ring System

    Institute of Scientific and Technical Information of China (English)

    XIONG Yong-Jian

    2006-01-01

    @@ We derive an exact expression for the transmission coefficient through an Aharonov-Bohm ring with a side-coupled quantum dot using the scattering-matrix approach. We show a sudden AB phase change by π as the quantum dot is tuned across the resonance. The Aharonov-Bohm oscillation amplitude can be modulated effectively by tuning the quantum dot level. The transmission coefficient has an expression of the generalized Fano form with a complex Fano parameter q in the presence of the Aharonov-Bohm flux.

  5. Fano Resonance of the Symmetry-Reduced Metal Bar Grating Structure

    Directory of Open Access Journals (Sweden)

    Suxia Xie

    2014-01-01

    Full Text Available We demonstrate that Fano resonance and even multipole Fano resonance can be obtained in a symmetry-reduced structure composed of gold bars with different bar sizes or bar shapes on a layer of dielectric. There is a transparency window opened within the frequency region of the absorptive dipole resonance by metallic bars, as long as the narrow grating waveguide mode induced by reducing symmetry is coincided in spectrum with the dipole resonance such that a destructive interference happens between these two resonant modes. Line shape of the transmission spectra of the nanostructure can be modulated effectively by changing the size or shape of the series of metal bars. The results found can be useful in the design of novel optical device.

  6. Reversible Fano resonance by transition from fast light to slow light in a coupled-resonator-induced transparency structure.

    Science.gov (United States)

    Zhang, Yundong; Zhang, Xuenan; Wang, Ying; Zhu, Ruidong; Gai, Yulong; Liu, Xiaoqi; Yuan, Ping

    2013-04-08

    We theoretically propose and experimentally perform a novel dispersion tuning scheme to realize a tunable Fano resonance in a coupled-resonator-induced transparency (CRIT) structure coupled Mach-Zehnder interferometer. We reveal that the profile of the Fano resonance in the resonator coupled Mach-Zehnder interferometers (RCMZI) is determined not only by the phase shift difference between the two arms of the RCMZI but also by the dispersion (group delay) of the CRIT structure. Furthermore, it is theoretically predicted and experimentally demonstrated that the slope and the asymmetry parameter (q) describing the Fano resonance spectral line shape of the RCMZI experience a sign reversal when the dispersion of the CRIT structure is tuned from abnormal dispersion (fast light) to normal dispersion (slow light). These theoretical and experimental results indicate that the reversible Fano resonance which holds significant implications for some attractive device applications such as highly sensitive biochemical sensors, ultrafast optical switches and routers can be realized by the dispersion tuning scheme in the RCMZI.

  7. Tunable multiple Fano resonances in magnetic single-layered core-shell particles

    CERN Document Server

    Arruda, Tiago Jose; Pinheiro, Felipe Arruda

    2015-01-01

    We investigate multiple Fano, comblike scattering resonances in single-layered, concentric core-shell nanoparticles composed of magnetic materials. Using the Lorenz-Mie theory, we derive, in the long-wavelength limit, an analytical condition for the occurrence of comblike resonances in the single scattering by coated spheres. This condition establishes that comblike scattering response uniquely depends on material parameters and thickness of the shell, provided that it is magnetic and thin compared to the scatterer radius. We also demonstrate that comblike scattering response shows up beyond the long-wavelength limit and it is robust against absorption. Since multiple Fano resonances are shown to depend explicitly on the magnetic permeability of the shell, we argue that both the position and profile of the comblike, morphology-dependent resonances could be externally tuned by exploiting the properties of engineered magnetic materials.

  8. A reconfigurable subwavelength plasmonic fano nano-antenna based on split ring resonator

    Science.gov (United States)

    Hosseinbeig, Ahmad; Pirooj, Azadeh; Zarrabi, Ferdows B.

    2017-02-01

    In this article, a reconfigurable subwavelength plasmonic nano-antenna with Fano resonance effect is presented based on the dual ring structure. In order to achieve reconfigurable characteristics, the interaction of gold with graphene is studied. SiN substrate with refractive index of 1.98 and gold with Palik optical characteristic modified for metal layer are utilized in the design of the proposed nano-antenna. Simulations are performed by using CST Microwave Studio. The biasing effect on extinction cross section is studied for 0 to 0.8 eV. It is shown that the gap method is useful for exciting the Fano resonance in the dual ring nano-antenna and there is only a plasmonic resonance in the simple dual ring antenna. The proposed nano-antenna is useful for THz medical spectroscopy due to its simple design and the ability to control the second resonance frequency by changing the bias of the graphene.

  9. High quality-factor fano metasurface comprising a single resonator unit cell

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, Michael B.; Warne, Larry K.; Basilio, Lorena I.; Langston, William L.; Campione, Salvatore; Brener, Igal; Liu, Sheng

    2017-06-20

    A new monolithic resonator metasurface design achieves ultra-high Q-factors while using only one resonator per unit cell. The metasurface relies on breaking the symmetry of otherwise highly symmetric resonators to induce intra-resonator mixing of bright and dark modes (rather than inter-resonator couplings), and is scalable from the near-infrared to radio frequencies and can be easily implemented in dielectric materials. The resulting high-quality-factor Fano metasurface can be used in many sensing, spectral filtering, and modulation applications.

  10. Nanoscale temperature sensor based on Fano resonance in metal-insulator-metal waveguide

    Science.gov (United States)

    Kong, Yan; Wei, Qi; Liu, Cheng; Wang, Shouyu

    2017-02-01

    In order to realize temperature measurements with high sensitivity using compact structure, a nanoscale metal-insulator-metal waveguide based sensor combining with Fano resonance is proposed in this paper. Sealed ethanol in resonant cavity is adopted to further improve sensing performance. Additionally, dual resonant cavity based configuration is designed to generate a Fano-based sharp and asymmetric spectrum, providing high figure of merit in measurements. Moreover, structural parameters are optimized considering both transmission rate and spectral peak width. Certified by numerical calculation, sensitivity of 0.36 nm/°C is acquired with the optimized structure, indicating the designed sensor can play an important role in the nano-integrated plasmonic devices for high-accurate temperature detection.

  11. Optical and acoustic sensing using Fano-like resonances in dual phononic and photonic crystal plate

    Energy Technology Data Exchange (ETDEWEB)

    Amoudache, Samira [Institut d' Electronique, de Microélectronique et de Nanotechnologie, Université de Lille 1, 59655 Villeneuve d' Ascq (France); Laboratoire de Physique et Chimie Quantique, Université Mouloud Mammeri, B.P. 17 RP, 15000 Tizi-Ouzou (Algeria); Moiseyenko, Rayisa [Department of Physics, Technical University of Denmark, DTU Physics, Building 309, DK-2800 Kongens Lyngby (Denmark); Pennec, Yan, E-mail: yan.pennec@univ-lille1.fr; Rouhani, Bahram Djafari [Institut d' Electronique, de Microélectronique et de Nanotechnologie, Université de Lille 1, 59655 Villeneuve d' Ascq (France); Khater, Antoine [Institut des Molécules et Matériaux du Mans (IMMM), UMR CNRS 6283, l' UNAM, Université du Maine, 72085 Le Mans (France); Lucklum, Ralf [Institute of Micro and Sensor Systems (IMOS), Otto-von-Guericke-University, P.O. Box 4120, D-39016 Magdeburg (Germany); Tigrine, Rachid [Laboratoire de Physique et Chimie Quantique, Université Mouloud Mammeri, B.P. 17 RP, 15000 Tizi-Ouzou (Algeria)

    2016-03-21

    We perform a theoretical study based on the transmissions of optical and acoustic waves normally impinging to a periodic perforated silicon plate when the embedded medium is a liquid and show the existence of Fano-like resonances in both cases. The signature of the resonances appears as well-defined asymmetric peaks in the phononic and photonic transmission spectra. We show that the origin of the Fano-like resonances is different with respect to the nature of the wave. In photonic, the origin comes from guided modes in the photonic plate while in phononic we show that it comes from the excitation of standing waves confined inside the cavity coming from the deformation of the water/silicon edges of the cylindrical inclusion. We finally use these features for sensing and show ultra-sensitivity to the light and sound velocities for different concentrations of analytes.

  12. A subwavelength plasmonic metamolecule exhibiting magnetic-based optical Fano resonance

    Science.gov (United States)

    Shafiei, Farbod; Monticone, Francesco; Le, Khai Q.; Liu, Xing-Xiang; Hartsfield, Thomas; Alù, Andrea; Li, Xiaoqin

    2013-02-01

    The lack of symmetry between electric and magnetic charges, a fundamental consequence of the small value of the fine-structure constant, is directly related to the weakness of magnetic effects in optical materials. Properly tailored plasmonic nanoclusters have been proposed recently to induce artificial optical magnetism based on the principle that magnetic effects are indistinguishable from specific forms of spatial dispersion of permittivity at optical frequencies. In a different context, plasmonic Fano resonances have generated a great deal of interest, particularly for use in sensing applications that benefit from sharp spectral features and extreme field localization. In the absence of natural magnetism, optical Fano resonances have so far been based on purely electric effects. In this Letter, we demonstrate that a subwavelength plasmonic metamolecule consisting of four closely spaced gold nanoparticles supports a strong magnetic response coupled to a broad electric resonance. Small structural asymmetries in the assembled nanoring enable the interaction between electric and magnetic modes, leading to the first observation of a magnetic-based Fano scattering resonance at optical frequencies. Our findings are supported by excellent agreement with simulations and analytical calculations, and represent an important step towards the quest for artificial magnetism and negative refractive index metamaterials at optical frequencies.

  13. Nanoparticle detection using fano-resonance photonic crystal on optical fiber-tip

    Science.gov (United States)

    Yang, Daquan; Yuan, Wei; Ji, Yuefeng

    2016-10-01

    Recently, Fano-resonance photonic crystals (PhC) have been employed within a wide variety of nanophotonic structures for different applications, including imaging, filtering, switching, sensing, and so on. In this paper, we propose a convenient and compact fiber-optic sensor based on optical fiber-tips integrated with Fano-resonance pillar-array PhC. The quality factor 1.04×104 and refractive index sensitivity of 226 nm per refractive index unit (RIU) have been demonstrated. In addition, the proposed Fiber-PhC integrated senor structure can be used for nanoparticle detection by checking the reflection spectrum shift with a narrow line-width. Using this method, we demonstrate that the detection of polystyrene nanoparticles with dimensions down to 50 nm in radius can be achieved. Thus, we believe that the design and results presented here are promising and enable the implementation of simple but functional fiber-optic sensors and devices.

  14. Fano resonance-based highly sensitive, compact temperature sensor on thin film lithium niobate.

    Science.gov (United States)

    Qiu, Wentao; Ndao, Abdoulaye; Vila, Venancio Calero; Salut, Roland; Courjal, Nadège; Baida, Fadi Issam; Bernal, Maria-Pilar

    2016-03-15

    In this Letter, we report a Fano resonance-based highly sensitive and compact temperature sensor fabricated on thin film lithium niobate (TFLN) Suzuki phase lattice (SPL) photonic crystal. The experimental sensitivity is estimated to be 0.77 nm/°C with a photonic crystal size of only 25  μm × 24  μm. This sensitivity is 38 times larger than the intrinsic one of lithium niobate which is 0.02 nm/°C. The demonstrated sharp and high extinction ratio characteristics of the Fano lineshape resonance could be an excellent candidate in developing a high sensitivity temperature sensor, electric field sensor, etc.

  15. Extra loss due to Fano resonances in inhibited coupling fibers based on a lattice of tubes.

    Science.gov (United States)

    Vincetti, L; Setti, V

    2012-06-18

    Confinement loss of inhibited coupling fibers with a cladding composed of a lattice of tubes of various shapes is theoretically and numerically investigated. Both solid core and hollow core are taken into account. It is shown that in case of polygonal shaped tubes, confinement loss is affected by extra loss due to Fano resonances between core modes and cladding modes with high spatial dependence. This explains why hollow core Kagome fibers exhibit much higher confinement loss with respect to tube lattice fibers and why hypocycloid core cladding interfaces significantly reduce fiber loss. Moreover it is shown that tube deformations, due for example to fabrication process, affect fiber performances. A relationship between the number of polygon sides and the spectral position of the extra loss is found. This suggests general guide lines for the design and fabrication of fibers free of Fano resonance in the spectral range of interest.

  16. Giant Goos-Hänchen effect and Fano resonance at photonic crystal surfaces.

    Science.gov (United States)

    Soboleva, I V; Moskalenko, V V; Fedyanin, A A

    2012-03-23

    The Goos-Hänchen effect and Fano resonance are studied in photonic crystals that are considered Fourier counterparts in wave-vector-coordinate space. The Goos-Hänchen effect, which is enhanced by the excitation of Bloch surface electromagnetic waves, is visualized using far-field microscopy and measured at the surface of photonic crystals by angular spectroscopy. The maximal Goos-Hänchen shift is observed to be 66  μm.

  17. Low Threshold, Wide Dynamic Range, Tunable, All-Optical Self-Modulator Based on Fano Resonance and Out-of-Plane Coupling in a Slab Photonic Crystal with a Graphene Layer

    Directory of Open Access Journals (Sweden)

    Reza Asadi

    2015-01-01

    Full Text Available We demonstrate an all-optical modulator based on self-modulation in a one-dimensional slab photonic crystal (PhC by using optical Kerr nonlinearity of graphene and Fano resonance effect. It has been shown that the effect of Fano resonance in a one-dimensional slab PhC for intensity enhancement can provide low threshold (~1 MW/cm2, high frequency (>1 THz, and wide dynamic range (>3 THz tunability for the all-optical self-modulator. Such a self-modulator can find applications in optical pulse generations, optical clocks, frequency shifting, and so forth.

  18. Prediction of quantum interference in molecular junctions using a parabolic diagram: Understanding the origin of Fano and anti-resonances

    DEFF Research Database (Denmark)

    Nozaki, Daijiro; Avdoshenko, Stanislav M.; Sevincli, Haldun;

    2013-01-01

    to predict the appearance of quantum interference, Fano resonances or anti- resonances, and its position in the conductance spectrum by introducing a simple graphical representation (parabolic model). Using it we can easily visualize the relation between the key electronic parameters and the positions...... of normal resonant peaks and anti-resonant peaks induced by quantum interference in the conductance spectrum. We also demonstrate Fano and anti-resonance in T-shaped molecular junctions using a simple tight-binding model. This parabolic model enables one to infer on-site energies of T-shaped molecules...

  19. Higher-order time-symmetry-breaking phase transition due to meeting of an exceptional point and a Fano resonance

    Science.gov (United States)

    Tanaka, Satoshi; Garmon, Savannah; Kanki, Kazuki; Petrosky, Tomio

    2016-08-01

    We have theoretically investigated the time-symmetry-breaking phase-transition process for two discrete states coupled with a one-dimensional continuum by solving the nonlinear eigenvalue problem for the effective Hamiltonian associated with the discrete spectrum. We obtain the effective Hamiltonian with use of the Feshbach-Brillouin-Wigner projection method. Strong energy dependence of the self-energy appearing in the effective Hamiltonian plays a key role in the time-symmetry-breaking phase transition: As a result of competition in the decay process between the Van Hove singularity and the Fano resonance, the phase transition becomes a higher-order transition when both the two discrete states are located near the continuum threshold.

  20. Directional Fano Resonances at Light Scattering by a High Refractive Index Dielectric Sphere

    CERN Document Server

    Tribelsky, Michael I; Litman, Amelie; Eyraud, Christelle; Moreno, Fernando

    2016-01-01

    In this research, we report the experimental evidence of the directional Fano resonances at the scattering of a plane, linearly polarized electromagnetic wave by a homogeneous dielectric sphere with high refractive index and low losses. We observe a typical asymmetric Fano profile for the intensity scattered in, practically, any given direction, while the overall extinction cross section remains Lorentzian. The phenomenon is originated in the interference of the selectively excited electric dipolar and quadrupolar modes. The selectivity of the excitation is achieved by the proper choice of the frequency of the incident wave. Thanks to the scaling invariance of the Maxwell equations, in these experiments we mimic the scattering of the visible and near IR radiation by a nanoparticle made of common superconductor materials (Si, Ge, GaAs, GaP) by the equivalent scattering of a spherical particle of 18 mm in diameter in the microwave range. The theory developed to explain the experiments extends the conventional F...

  1. Nonperturbative spin-boson and spin-spin dynamics and nonlinear Fano interferences: a unified dissipaton theory based study.

    Science.gov (United States)

    Zhang, Hou-Dao; Xu, Rui-Xue; Zheng, Xiao; Yan, YiJing

    2015-01-14

    We consider the hybrid system-bath dynamics, based on the Yan's dissipaton formalism [Y. J. Yan, J. Chem. Phys. 140, 054105 (2014)]. This theory provides a unified quasi-particle treatment on three distinct classes of quantum bath, coupled nonperturbatively to arbitrary quantum systems. In this work, to study the entangled system and bath polarization and nonlinear Fano interference, we incorporate further the time-dependent light field, which interacts with both the molecular system and the collective bath dipoles directly. Numerical demonstrations are carried out on a two-level system, with comparison between phonon and exciton baths, in both linear and nonlinear Fano interference regimes.

  2. Self-induced light trapping in nonlinear Fabry-Perot resonators

    Science.gov (United States)

    Pichugin, K. N.; Sadreev, A. F.

    2016-10-01

    In the framework of the coupled mode theory we consider light trapping between two off-channel resonators which serve as self-adjusted Fano mirrors due to the Kerr effect. By inserting an auxiliary nonlinear resonator between the mirrors we achieve self-tuning of phase shift between the mirrors. That allows for the light trapping for arbitrary distance between the mirrors.

  3. Broken symmetry dielectric resonators for high quality-factor Fano metasurfaces

    CERN Document Server

    Campione, Salvatore; Basilio, Lorena I; Warne, Larry K; Langston, William L; Luk, Ting S; Wendt, Joel R; Reno, John L; Keeler, Gordon A; Brener, Igal; Sinclair, Michael B

    2016-01-01

    We present a new approach to dielectric metasurface design that relies on a single resonator per unit cell and produces robust, high quality-factor Fano resonances. Our approach utilizes symmetry breaking of highly symmetric resonator geoemetries, such as cubes, to induce couplings between the otherwise orthogonal resonator modes. In particular, we design perturbations that couple "bright" dipole modes to "dark" dipole modes whose radiative decay is suppressed by local field effects in the array. Our approach is widely scalable from the near-infrared to radio frequencies. We first unravel the Fano resonance behavior through numerical simulations of a germanium resonator-based metasurface that achieved a quality-factor of ~1300 at ~10.8 um. Then, we present two experimental demonstrations operating in the near-infrared (~1 um): a silicon-based implementation that achieved a quality-factor of ~350; and a gallium arsenide-based structure that achieves a quality-factor of ~600 - the highest near-infrared quality-...

  4. Electronic Raman scattering and the Fano resonance in metallic carbon nanotubes

    Science.gov (United States)

    Hasdeo, Eddwi H.; Nugraha, Ahmad R. T.; Sato, Kentaro; Dresselhaus, Mildred S.; Saito, Riichiro

    2013-09-01

    The Fano resonance spectra for the G band in metallic carbon nanotubes are calculated as a function of laser excitation energy, in which the origin of the resonance is given by an interference between the continuous electronic Raman spectra and the discrete phonon spectra. We found that the second-order scattering process of the q≠0 electron-electron interaction is more relevant to the continuous spectra rather than the q=0 first-order process because the q=0 direct Coulomb interaction vanishes due to the symmetry of the two sublattices of a carbon nanotube.

  5. Interplay of magnetic responses in all-dielectric oligomers to realize magnetic Fano resonances

    CERN Document Server

    Hopkins, Ben; Miroshnichenko, Andrey E; Monticone, Francesco; Alù, Andrea; Kivshar, Yuri S

    2016-01-01

    We study the interplay between collective and individual optically-induced magnetic responses in quadrumers made of identical dielectric nanoparticles. Unlike their plasmonic counterparts, all-dielectric nanoparticle clusters are shown to exhibit multiple dimensions of resonant magnetic responses that can be employed for the realization of anomalous scattering signatures. We focus our analysis on symmetric quadrumers made from silicon nanoparticles and verify our theoretical results in proof-of-concept radio frequency experiments demonstrating the existence of a novel type of magnetic Fano resonance in nanophotonics.

  6. Fano Resonance Based on Metal-Insulator-Metal Waveguide-Coupled Double Rectangular Cavities for Plasmonic Nanosensors

    Directory of Open Access Journals (Sweden)

    Zhidong Zhang

    2016-05-01

    Full Text Available A refractive index sensor based on metal-insulator-metal (MIM waveguides coupled double rectangular cavities is proposed and investigated numerically using the finite element method (FEM. The transmission properties and refractive index sensitivity of various configurations of the sensor are systematically investigated. An asymmetric Fano resonance lineshape is observed in the transmission spectra of the sensor, which is induced by the interference between a broad resonance mode in one rectangular and a narrow one in the other. The effect of various structural parameters on the Fano resonance and the refractive index sensitivity of the system based on Fano resonance is investigated. The proposed plasmonic refractive index sensor shows a maximum sensitivity of 596 nm/RIU.

  7. Magnetic-dipolar-mode Fano resonances for microwave spectroscopy of high absorption matter

    Science.gov (United States)

    Vaisman, G.; Kamenetskii, E. O.; Shavit, R.

    2015-03-01

    The interaction between high absorption matter and microwave radiated energy is a subject of great importance. In particular, this concerns the microwave spectroscopic characterization of biological liquids. The use of effective testing methods to obtain information about physical properties of different liquids on the molecular level is one of the most important problems in biophysics. However, the standard methods based on microwave resonant techniques are not sufficiently suitable for biological liquids because the resonance peak in a resonator with high-loss liquids is so broad that the material parameters cannot be measured correctly. Although molecular vibrations of biomolecules may have microwave frequencies, it is not thought that such resonant coupling is significant due to their low energy compared with thermal energy and the strongly dampening aqueous environment. This paper presents an innovative microwave sensing technique for different types of lossy materials, including biological liquids. The technique is based on the combination of the microwave perturbation method and the Fano resonance effects observed recently in microwave structures with embedded magnetic-dipolar quantum dots. When the frequency of the magnetic dipolar mode (MDM) resonance is not equal to the cavity resonance frequency, one gets Fano transmission intensity. When the MDM resonance frequency is tuned to the cavity resonance frequency, by a bias magnetic field, one observes a Lorentzian line shape. Use of an extremely narrow Lorentzian peak allows exact probing of the resonant frequency of a cavity loaded by a highly lossy material sample. For different kinds of samples, one has different frequencies of Lorentzian peaks. This presents a picture of precise spectroscopic characterization of high absorption matter in microwaves.

  8. Fano coil-type resonances: a plasmonic tool for magnetic field enhancement (Conference Presentation)

    Science.gov (United States)

    Panaro, Simone; Proietti Zaccaria, Remo; Toma, Andrea

    2016-09-01

    Spintronics and spin-based technology rely on the ultra-fast unbalance of the electronic spin population in quite localized spatial regions. However, as a matter of fact, the low susceptibility of conventional materials at high frequencies strongly limits these phenomena, rendering the efficiency of magnetically active devices insufficient for application purposes. Among the possible strategies which can be envisaged, plasmonics offers a direct approach to increase the effect of local electronic unbalancing processes. By confining and enhancing free radiation in nm-size spatial regions, plasmonic nano-assemblies have demonstrated to support very intense electric and magnetic hot-spots. In particular, very recent studies have proven the fine control of magnetic fields in Fano resonance condition. The near-field-induced out-of-phase oscillation of localized surface plasmons has manifested itself with the arising of magnetic sub-diffractive hot-spots. Here, we show how this effect can be further boosted in the mid-infrared regime via the introduction of higher order plasmonic modes. The investigated system, namely Moon Trimer Resonator, combines the high efficiency of a strongly coupled nano-assembly in Fano interferential condition with the elevated tunability of the quadrupolar resonance supported by a moon-like geometry. The fine control of the apical gap in this unique nanostructure, characterizes a plasmonic device able to tune its resonance without any consequence on the magnetic hot-spot size, thus enabling an efficient squeezing in the infrared.

  9. Fano coil-type resonances: a plasmonic tool for the magnetic field manipulation (Conference Presentation)

    Science.gov (United States)

    Panaro, Simone; Proietti Zaccaria, Remo; Toma, Andrea

    2017-02-01

    Spintronics and spin-based technology rely on the ultra-fast unbalance of the electronic spin population in quite localized spatial regions. However, as a matter of fact, the low susceptibility of conventional materials at high frequencies strongly limits these phenomena, rendering the efficiency of magnetically active devices insufficient for application purposes. Among the possible strategies which can be envisaged, plasmonics offers a direct approach to increase the effect of local electronic unbalancing processes. By confining and enhancing free radiation in nm-size spatial regions, plasmonic nano-assemblies have demonstrated to support very intense electric and magnetic hot-spots. In particular, very recent studies have proven the fine control of magnetic fields in Fano resonance condition. The near-field-induced out-of-phase oscillation of localized surface plasmons has manifested itself with the arising of magnetic sub-diffractive hot-spots. Here, we show how this effect can be further boosted in the mid-infrared regime via the introduction of higher order plasmonic modes. The investigated system, namely Moon Trimer Resonator (MTR), combines the high efficiency of a strongly coupled nano-assembly in Fano interferential condition with the elevated tunability of the quadrupolar resonance supported by a moon-like geometry. The fine control of the apical gap in this unique nanostructure, characterizes a plasmonic device able to tune its resonance without any consequence on the magnetic hot-spot size, thus enabling an efficient squeezing in the infrared.

  10. Dynamic control of the asymmetric Fano resonance in side-coupled Fabry–Pérot and photonic crystal nanobeam cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Tong; Chau, Fook Siong; Zhou, Guangya, E-mail: mpezgy@nus.edu.sg [Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore); Deng, Jie [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore)

    2015-11-30

    Fano resonance is a prevailing interference phenomenon that stems from the intersection between discrete and continuum states in many fields. We theoretically and experimentally characterize the asymmetric Fano lineshape in side-coupled waveguide Fabry–Pérot and photonic crystal nanobeam cavities. The measured quality-factor of the Fano resonance before tuning is 28 100. A nanoelectromechanical systems bidirectional actuator is integrated seamlessly to control the shape of the Fano resonance through in-plane translations in two directions without sacrificing the quality-factor. The peak intensity level of the Fano resonance can be increased by 8.5 dB from 60 nW to 409 nW while the corresponding dip intensity is increased by 12.8 dB from 1 nW to 18 nW. The maximum recorded quality-factor throughout the tuning procedure is up to 32 500. Potential applications of the proposed structure include enhancing the sensitivity of sensing, reconfigurable nanophotonics devices, and on-chip intensity modulator.

  11. Investigation of Fano resonances induced by higher order plasmon modes on a circular nano-disk with an elongated cavity

    KAUST Repository

    Amin, Muhammad Ruhul

    2012-08-10

    In this paper, a planar metallic nanostructure design, which supports two distinct Fano resonances in its extinction cross-section spectrum under normally incident and linearly polarized electromagnetic field, is proposed. The proposed design involves a circular disk embedding an elongated cavity; shifting and rotating the cavity break the symmetry of the structure with respect to the incident field and induce higher order plasmon modes. As a result, Fano resonances are generated in the visible spectrum due to the destructive interference between the sub-radiant higher order modes and super-radiant the dipolar mode. The Fano resonances can be tuned by varying the cavity\\'s width and the rotation angle. An RLC circuit, which is mathematically equivalent to a mass-spring oscillator, is proposed to model the optical response of the nanostructure design.

  12. Fano versus Kondo Resonances in a Closed Aharonov-Bohm Interferometer Coupled to Ferromagnetic Electrodes

    Institute of Scientific and Technical Information of China (English)

    WU Shao-Quan; SUN Wei-Li

    2007-01-01

    Using the Keldysh Nonequilibrium Green function and equation-of-motion technique,we investigate Fano versus Kondo resonances in closed Aharonov-Bohm interferometer coupled to ferromagnetic leads and study their effects on the conductance of this system.The conductance with both parallel and antiparallel lead-polarization alignments is analysed for various values of the magnetic flux.Our results show that this system can provide an excellent spin filtering property,and a large tunnelling magnetoresistance can arise by adjusting the system parameters,which indicates that this system is a possible candidate for spin valve transistors and has important applications in spintronics.

  13. Optical and acoustic sensing using Fano-like resonances in dual phononic and photonic crystal plate

    DEFF Research Database (Denmark)

    Amoudache, Samira; Moiseyenko, Rayisa; Pennec, Yan;

    2016-01-01

    -defined asymmetric peaks in the phononic and photonic transmission spectra. We show that the origin of the Fano-like resonances is different with respect to the nature of the wave. In photonic, the origin comes from guided modes in the photonic plate while in phononic we show that it comes from the excitation...... of standing waves confined inside the cavity coming from the deformation of the water/silicon edges of the cylindrical inclusion. We finally use these features for sensing and show ultra-sensitivity to the light and sound velocities for different concentrations of analytes....

  14. Fano-like resonance emerging from magnetic and electric plasmon mode coupling in small arrays of gold particles

    Science.gov (United States)

    Bakhti, Saïd; Tishchenko, Alexandre V.; Zambrana-Puyalto, Xavier; Bonod, Nicolas; Dhuey, Scott D.; Schuck, P. James; Cabrini, Stefano; Alayoglu, Selim; Destouches, Nathalie

    2016-09-01

    In this work we theoretically and experimentally analyze the resonant behavior of individual 3 × 3 gold particle oligomers illuminated under normal and oblique incidence. While this structure hosts both dipolar and quadrupolar electric and magnetic delocalized modes, only dipolar electric and quadrupolar magnetic modes remain at normal incidence. These modes couple into a strongly asymmetric spectral response typical of a Fano-like resonance. In the basis of the coupled mode theory, an analytical representation of the optical extinction in terms of singular functions is used to identify the hybrid modes emerging from the electric and magnetic mode coupling and to interpret the asymmetric line profiles. Especially, we demonstrate that the characteristic Fano line shape results from the spectral interference of a broad hybrid mode with a sharp one. This structure presents a special feature in which the electric field intensity is confined on different lines of the oligomer depending on the illumination wavelength relative to the Fano dip. This Fano-type resonance is experimentally observed performing extinction cross section measurements on arrays of gold nano-disks. The vanishing of the Fano dip when increasing the incidence angle is also experimentally observed in accordance with numerical simulations.

  15. Attosecond dynamics through a Fano resonance: Monitoring the birth of a photoelectron

    Science.gov (United States)

    Gruson, V.; Barreau, L.; Jiménez-Galan, Á.; Risoud, F.; Caillat, J.; Maquet, A.; Carré, B.; Lepetit, F.; Hergott, J.-F.; Ruchon, T.; Argenti, L.; Taïeb, R.; Martín, F.; Salières, P.

    2016-11-01

    The dynamics of quantum systems are encoded in the amplitude and phase of wave packets. However, the rapidity of electron dynamics on the attosecond scale has precluded the complete characterization of electron wave packets in the time domain. Using spectrally resolved electron interferometry, we were able to measure the amplitude and phase of a photoelectron wave packet created through a Fano autoionizing resonance in helium. In our setup, replicas obtained by two-photon transitions interfere with reference wave packets that are formed through smooth continua, allowing the full temporal reconstruction, purely from experimental data, of the resonant wave packet released in the continuum. In turn, this resolves the buildup of the autoionizing resonance on an attosecond time scale. Our results, in excellent agreement with ab initio time-dependent calculations, raise prospects for detailed investigations of ultrafast photoemission dynamics governed by electron correlation, as well as coherent control over structured electron wave packets.

  16. Sensitive temperature measurements based on Lorentzian and Fano resonance lineshapes of a silicon photonic crystal cavity

    Science.gov (United States)

    Zhao, Chenyang; Fang, Liang; Yuan, Qinchen; Gan, Xuetao; Zhao, Jianlin

    2016-10-01

    We report a high-performance photonic temperature sensor by exploiting a silicon photonic crystal (PC) cavity. Since the PC cavity's spectra are very sensitive to the refractive index change, we observe remarkable variations of its resonant wavelength and output power under varying temperature levels. In a PC cavity with Lorentzian resonance lineshape, the sensor exhibits a linear spectrum-sensitivity of 70 pm/°, and the power-variation presents a high sensitivity as 1.28 dB/°. In addition, the Fano resonance lineshape generated by the PC cavity has also been employed to measure the temperature, which shows improved power sensitivity as 2.94 dB/ °. The demonstrated PC cavity-based sensor offers great potentials for low-cost, high sensitivity homogeneous sensing in chip-integrated devices.

  17. Fano resonance and the hidden order in URu2 Si 2 probed by quasiparticle scattering spectroscopy*

    Science.gov (United States)

    Park, W. K.; Greene, L. H.; Bauer, E. D.; Tobash, P. H.; Ronning, F.; Lu, X.; Sarrao, J. L.; Thompson, J. D.

    2011-03-01

    The nature of the hidden order transition occurring at 17.5 K in URu 2 Si 2 remains puzzling despite intensive investigations over the past two and half decades. Recent experimental and theoretical developments render it a timely subject to probe the hidden order state using quasiparticle tunneling and scattering techniques. We report on the Fano resonance in pure and Rh-doped URu 2 Si 2 single crystals using point-contact spectroscopy. The conductance spectra reproducibly reveal asymmetric double peak structures slightly off-centered around zero bias with the two peaks merging well above the hidden order transition temperature. An analysis using the Fano resonance model in a Kondo lattice [1] shows that the conductance peaks arise from the hybridization gap opening. Our estimated gap size agrees well with those reported from other measurements. We will present experimental results over a wide parameter space including temperature and doping dependences and discuss their underlying physics. M. Maltseva, M. Dzero, and P. Coleman, Phys. Rev. Lett. 103, 206402 (2009). * The work at UIUC is supported by the U.S. DOE under Award Nos. DE-FG02-07ER46453 and DE-AC02-98CH10886, and the work at LANL is carried out under the auspices of the U.S. DOE, Office of Science.

  18. Fano resonance in graphene-MoS2 heterostructure-based surface plasmon resonance biosensor and its potential applications

    Science.gov (United States)

    Zheng, Gaige; Zou, Xiujuan; Chen, Yunyun; Xu, Linhua; Rao, Weifeng

    2017-04-01

    We propose a new configuration of surface plasmon resonance (SPR) sensor that is based on graphene-MoS2 hybrid structures for ultrasensitive detection of molecules. The present configuration is consisted of chalcogenide glass (2S2G) prism, Ag, coupling layer, guiding layer, graphene-MoS2 heterostructure and analyte. We perform numerical and analytical study of the impact of the thickness and refractive index (RI) of the coupling and guiding layer in a planar sensing structure within the Kretschmann configuration on the resonance properties of the excitation. Results of reflectivity calculations clearly demonstrate the sharp Fano-type resonance appears in the curve of SPR because of the coupling between surface plasmon polariton (SPP) and planar waveguide (PWG) modes. The properties of the Fano resonance (FR) strongly depend on the parameters of the structure. The calculated magnetic field profiles manifest that the hybrid nature of the electromagnetic (EM) modes excited in the present structure. The proposed system displays an enhancement factor of sensitivity by intensity more than 2 × 103-fold when compared to the SPR sensing scheme.

  19. Density-near-zero using the acoustically induced transparency of a Fano acoustic resonator

    KAUST Repository

    Elayouch, A.

    2017-01-05

    We report experimental results of near-zero mass density involving an acoustic metamaterial supporting Fano resonance. For this, we designed and fabricated an acoustic resonator with two closely coupled modes and measured its transmission properties. Our study reveals that the phenomenon of acoustically induced transparency is accompanied by an effect of near-zero density. Indeed, the dynamic effective parameters obtained from experimental data show the presence of a frequency band where the effective mass density is close to zero, with high transmission levels reaching 0.7. Furthermore, we demonstrate that such effective parameters lead to wave guiding in a 90-degrees-bent channel. This kind of acoustic metamaterial can, therefore, give rise to acoustic functions like controlling the wavefront, which may lead to very promising applications in acoustic cloacking or imaging.

  20. Optical magnetism and plasmonic Fano resonances in metal-insulator-metal oligomers.

    Science.gov (United States)

    Verre, R; Yang, Z J; Shegai, T; Käll, M

    2015-03-11

    The possibility of achieving optical magnetism at visible frequencies using plasmonic nanostructures has recently been a subject of great interest. The concept is based on designing structures that support plasmon modes with electron oscillation patterns that imitate current loops, that is, magnetic dipoles. However, the magnetic resonances are typically spectrally narrow, thereby limiting their applicability in, for example, metamaterial designs. We show that a significantly broader magnetic response can be realized in plasmonic pentamers constructed from metal-insulator-metal (MIM) sandwich particles. Each MIM unit acts as a magnetic meta-atom and the optical magnetism is rendered quasi-broadband through hybridization of the in-plane modes. We demonstrate that scattering spectra of individual MIM pentamers exhibit multiple Fano resonances and a broad subradiant spectral window that signals the magnetic interaction and a hierarchy of coupling effects in these intricate three-dimensional nanoparticle oligomers.

  1. Observation of Fano resonance and classical analog of electromagnetically induced transparency in toroidal metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Han, Song; Yang, Helin [College of Physical Science and Technology, Central China Normal University, Wuhan (China); Cong, Lonqing; Singh, Ranjan [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore (Singapore); Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore (Singapore); Gao, Fei [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore (Singapore)

    2016-05-15

    Toroidal multipoles have recently been explored in various scientific communities, ranging from atomic and molecular physics, electrodynamics, and solid-state physics to biology. Here we experimentally and numerically demonstrate a three-dimensional toroidal metamaterial where two different toroidal dipoles along orthogonal directions have been observed. The chosen toroidal metamaterial also simultaneously supports Fano resonance and the classical analog of electromagnetically induced transparency (EIT) phenomena in the transmission spectra that originate from the electric-toroidal dipole and electric-magnetic dipole destructive interference. The intriguing properties of the toroidal resonances may open up avenues for applications in toroidal moments generator, sensing and slow-light devices. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Strong Modulation of Infrared Light using Graphene Integration with Plasmonic Fano-Resonant Metasurfaces

    CERN Document Server

    Dabidian, Nima; Khanikaev, Alexander B; Tatar, Kaya; Trendafilov, Simeon; Mousavi, S Hossein; Magnuson, Carl; Ruoff, Rodney S; Shvets, Gennady

    2014-01-01

    Plasmonic metasurfaces represent a promising platform for enhancing light-matter interaction. Active control of the optical response of metasurfaces is desirable for applications such as beam-steering, modulators and switches, biochemical sensors, and compact optoelectronic devices. Here we use a plasmonic metasurface with two Fano resonances to enhance the interaction of infrared light with electrically controllable single layer graphene. It is experimentally shown that the narrow spectral width of these resonances, combined with strong light/graphene coupling, enables reflectivity modulation by nearly an order of magnitude leading to a modulation depth as large as 90%. . Numerical simulations demonstrate the possibility of strong active modulation of the phase of the reflected light while keeping the reflectivity nearly constant, thereby paving the way to tunable infrared lensing and beam steering

  3. Tunable Fano resonance and magneto-optical response in magnetoplasmonic structure fabricated by pure ferromagnetic metals

    Science.gov (United States)

    Chen, Leyi; Gao, Jinlong; Xia, Wenbin; Zhang, Shaoyin; Tang, Shaolong; Zhang, Weiyi; Li, Daoyong; Wu, Xiaoshan; Du, Youwei

    2016-06-01

    The developments in nanophotonics demand more efficient and delicate control of light. It has recently been proposed to achieve this goal by combining plasmonics and magneto-optics in so-called magnetoplasmonic nanostructures. However, significant challenges still remain because of the difficulty in the design of spectrally tunable systems exhibiting novel plasmonic and magneto-optical responses simultaneously. Here we report a magnetoplasmonic structure which consists of a two-dimensional nickel nanodisk array on top of a cobalt film substrate. We demonstrate that a tunable Fano resonance can be generated in this system with properly designed geometric parameters. Furthermore, the magneto-optical Kerr responses in this system can be manipulated due to the concerted actions of free electrons in the resonance. Our results reveal the possibility of fabricating large-area magnetoplasmonic structures by a simple, mass-producible method, and tuning the plasmonic and magneto-optical responses simultaneously.

  4. Fano resonances in photoconductivity spectra of hydrogen donors in ZnO and rutile

    Science.gov (United States)

    Lavrov, E. V.; Herklotz, F.; Weber, J.

    2015-02-01

    The results of photoconductivity studies of hydrogen donors in ZnO and rutile TiO2 are presented. It is shown that local vibrational modes of O-H bonds comprising donors in both semiconductors can be detected in photoconductivity spectra as Fano resonances at 3611 and 3290 cm-1 in the case of ZnO and TiO2, respectively. The frequencies of these features red-shift in energy down to 2668 (ZnO) and 2445 cm-1 (TiO2) if hydrogen is substituted by deuterium. Based on the frequency of the deuterium resonance it is concluded that the ionization energy of the hydrogen donor in TiO2 is less than 300 meV, which is in variance with predictions of theory. The reasons for such a discrepancy are discussed.

  5. The electronic conductance of polypyrrole (PPy molecular wires and emergence of Fano resonance phenomena

    Directory of Open Access Journals (Sweden)

    M Mardaani

    2012-06-01

    Full Text Available In this paper, we studied the electronic conductance of a polypyrrole polymer, which is embedded between two semi-infinite simple chains by using Green’s function technique in tight-binding approach. We first reduced the center polymer to a one dimensional chain with renormalized onsite and hopping energies by renormalization method. Then, we calculated the system conductivity as a function of incoming electron energy, polymer length and contact hopping terms. The results showed that by increasing polymer length and decreasing contact hopping energies, the conductance decreases in the gap regions. This means that for larger gaps, the electron tunneling happens with more difficulty. Moreover, at the resonance area, due to the existence of nitrogen atom in the polymer cyclic structure, the Fano resonance will emerge. Furthermore, the polymer can behave like a metallic chain by variation of the value of nitrogen on-site term.

  6. Giant exciton Fano resonance in quasi-one-dimensional Ta2NiSe5

    Science.gov (United States)

    Larkin, T. I.; Yaresko, A. N.; Pröpper, D.; Kikoin, K. A.; Lu, Y. F.; Takayama, T.; Mathis, Y.-L.; Rost, A. W.; Takagi, H.; Keimer, B.; Boris, A. V.

    2017-05-01

    We report the complex dielectric function of the quasi-one-dimensional chalcogenide Ta2NiSe5 , which undergoes a structural phase transition presumably associated with exciton condensation below Tc=326 K [Y. Wakisaka et al., Phys. Rev. Lett. 103, 026402 (2009), 10.1103/PhysRevLett.103.026402; Y. F. Lu et al., Nat. Commun. 8, 14408 (2017), 10.1038/ncomms14408], and of the isostructural Ta2NiS5 , which does not exhibit such a transition. Using spectroscopic ellipsometry, we have detected exciton doublets with pronounced Fano line shapes in both the compounds. The exciton Fano resonances in Ta2NiSe5 display an order-of-magnitude higher intensity than those in Ta2NiS5 . In conjunction with prior theoretical work [E. Rashba, Sov. Phys. Semicond. 8, 807 (1975)], we attribute this observation to the giant oscillator strength of spatially extended exciton-phonon bound states in Ta2NiSe5 . The formation of exciton-phonon complexes in Ta2NiS5 and Ta2NiSe5 is confirmed by the pronounced temperature dependence of sharp interband transitions in the optical spectra, the peak energies and widths of which scale with the thermal population of optical phonon modes. The description of the optically excited states in terms of strongly overlapping exciton complexes is in good agreement with the hypothesis of an exciton insulator ground state.

  7. Graphene plasmonics: multiple sharp Fano resonances in silver split concentric nanoring/disk resonator dimers on a metasurface

    Science.gov (United States)

    Ahmadivand, Arash; Sinha, Raju; Pala, Nezih

    2015-08-01

    We introduce a platform based on plasmonic metamaterials to design various optical devices. A simple structure brokenring with a nanodisk at the center is utilized to excite and hybridize the plasmon resonant modes. We show that the proposed nanoantenna is able to support strong sub- and superradiant plasmon resonances because of its unique geometrical features. Using the concentric ring/disk in a dimer orientation as a nanoantenna on a multilayer metasurface consisting of graphene monolayer, we induced double sharp plasmonic Fano resonant modes in the transmission window across the visible to the near-infrared region. Considering the strong polarization-dependency of the broken-ring/disk dimer antenna, it is shown that the proposed plasmonic metamaterial can be tailored as an optical router device for fast switching applications. This understanding opens new paths to employ plasmonic metamaterials with simple geometrical nanoscale blocks for sensing and switching applications.

  8. Switching from visibility to invisibility via Fano resonances: theory and experiment

    CERN Document Server

    Rybin, Mikhail V; Belov, Pavel A; Kivshar, Yuri S; Limonov, Mikhail F

    2014-01-01

    Subwavelength structures demonstrate many unusual optical properties which can be employed for engineering functional metadevices, as well as scattering of light and invisibility cloaking. Here we demonstrate that the suppression of light scattering for any direction of observation can be achieved for an uniform dielectric object with high refractive index, in a sharp contrast to the cloaking with multilayered plasmonic structures suggested previously. Our finding is based on the novel physics of cascades of Fano resonances observed in the Mie scattering from a homogeneous dielectric rod. We observe this effect experimentally at microwaves by employing high temperature-dependent dielectric permittivity of a glass cylinder with heated water. Our results open a new avenue in analyzing the optical response of hight-index dielectric nanoparticles and the physics of cloaking.

  9. Switching from visibility to invisibility via Fano resonances: theory and experiment.

    Science.gov (United States)

    Rybin, Mikhail V; Filonov, Dmitry S; Belov, Pavel A; Kivshar, Yuri S; Limonov, Mikhail F

    2015-03-05

    Subwavelength structures demonstrate many unusual optical properties which can be employed for engineering of a new generation of functional metadevices, as well as controlled scattering of light and invisibility cloaking. Here we demonstrate that the suppression of light scattering for any direction of observation can be achieved for a uniform dielectric object with high refractive index, in a sharp contrast to the cloaking with multilayered plasmonic structures suggested previously. Our finding is based on the novel physics of cascades of Fano resonances observed in the Mie scattering from a homogeneous dielectric rod. We observe this effect experimentally at microwaves by employing high temperature-dependent dielectric permittivity of a glass cylinder with heated water. Our results open a new avenue in analyzing the optical response of high-index dielectric nanoparticles and the physics of cloaking.

  10. Sensor based on Fano resonances of plane metamaterial with narrow slits

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wan-Xia, E-mail: kate@mail.ahnu.edu.cn [State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Physics Department, Fudan University, Shanghai 200433 (China); The College of Physics and Electronic Information, Anhui Normal University, Wuhu, Anhui 241000 (China); Guo, Juan-Juan; Wang, Mao-Sheng; Zhao, Guo-Ren [The College of Physics and Electronic Information, Anhui Normal University, Wuhu, Anhui 241000 (China)

    2017-03-11

    The optical properties of a composite metamaterial composed of narrow slits and nano hole pairs have been investigated experimentally and numerically. The strength of the transmission peak originating from the interference between the coupled surface plasmon polaritons (SPP) of the narrow slit and the SPP modes of the hole array is modulated by the degree of symmetry breaking. Some SPP modes can be inhibited by controlling the spacer layer thickness. Our metamaterial has potential applications in sensing and weak signal detection. - Highlights: • The plasmonic nanostructure composed of narrow slits and nano hole pairs were designed. • The optical properties were investigated experimentally and numerically. • The Fano resonances were found on the compound nanostructure. • The results have potential applications in sensing and weak signal detection.

  11. Broadband Slow Light Metamaterial Based on a Double-Continuum Fano Resonance

    CERN Document Server

    Wu, Chihhui; Shvets, Gennady

    2010-01-01

    We propose a concept of a low-symmetry three-dimensional metamaterial exhibiting a Double- Continuum Fano (DCF) optical resonance. Such metamaterial is described as a birefringent medium supporting a discrete “dark” electromagnetic state weakly coupled to the continua of two nondegen- erate “bright” bands of orthogonal polarizations. It is demonstrated that light propagation through such DCF metamaterial can be slowed down over a broad frequency range when the medium param- eters (e.g. frequency of the “dark” mode) are adiabatically changed along the optical path. Using a specific metamaterial implementation, we demonstrate that the DCF approach to slow light (SL) is superior to that of the EIT because it enables spectrally uniform group velocity and transmission coefficient.

  12. Prediction of quantum interference in molecular junctions using a parabolic diagram: Understanding the origin of Fano and anti- resonances

    Science.gov (United States)

    Nozaki, Daijiro; Avdoshenko, Stanislav M.; Sevinçli, Hâldun; Gutierrez, Rafael; Cuniberti, Gianaurelio

    2013-03-01

    Recently the interest in quantum interference (QI) phenomena in molecular devices (molecular junctions) has been growing due to the unique features observed in the transmission spectra. In order to design single molecular devices exploiting QI effects as desired, it is necessary to provide simple rules for predicting the appearance of QI effects such as anti-resonances or Fano line shapes and for controlling them. In this study, we derive a transmission function of a generic molecular junction with a side group (T-shaped molecular junction) using a minimal toy model. We developed a simple method to predict the appearance of quantum interference, Fano resonances or anti- resonances, and its position in the conductance spectrum by introducing a simple graphical representation (parabolic model). Using it we can easily visualize the relation between the key electronic parameters and the positions of normal resonant peaks and anti-resonant peaks induced by quantum interference in the conductance spectrum. We also demonstrate Fano and anti-resonance in T-shaped molecular junctions using a simple tight-binding model. This parabolic model enables one to infer on-site energies of T-shaped molecules and the coupling between side group and main conduction channel from transmission spectra.

  13. Far-field Fano resonance in nanoring lattices modeled from extracted, point dipole polarizability

    Energy Technology Data Exchange (ETDEWEB)

    DeJarnette, Drew; Forcherio, Gregory T. [Microelectronics and Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Blake, Phillip [Department of Chemical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Keith Roper, D., E-mail: dkroper@uark.edu [Microelectronics and Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Department of Chemical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

    2014-01-14

    Coupling and extinction of light among particles representable as point dipoles can be characterized using the coupled dipole approximation (CDA). The analytic form for dipole polarizability of spheroidal particles supports rapid electrodynamic analysis of nanoparticle lattices using CDA. However, computational expense increases for complex shapes with non-analytical polarizabilities which require discrete dipole (DDA) or higher order approximations. This work shows fast CDA analysis of assembled nanorings is possible using a single dipole nanoring polarizability extrapolated from a DDA calculation by summing contributions from individual polarizable volume elements. Plasmon resonance wavelengths of nanorings obtained using extracted polarizabilities blueshift as wall dimensions-to-inner radius aspect ratio increases, consistent with published theory and experiment. Calculated far-field Fano resonance energy maximum and minimum wavelengths were within 1% of full volume element results. Considering polarizability allows a more complete physical picture of predicting plasmon resonance location than metal dielectric alone. This method reduces time required for calculation of diffractive coupling more than 40 000-fold in ordered nanoring systems for 400–1400 nm incident wavelengths. Extension of this technique beyond nanorings is possible for more complex shapes that exhibit dipolar or quadrupole radiation patterns.

  14. Fano resonance in the nonadiabatically pumped shot noise of a time-dependent quantum well in a two-dimensional electron gas and graphene

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Rui, E-mail: rzhu@scut.edu.cn; Dai, Jiao-Hua [Department of Physics, South China University of Technology, Guangzhou 510641 (China); Guo, Yong [Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)

    2015-04-28

    Interference between different quantum paths can generate Fano resonance. One of the examples is transport through a quasibound state driven by a time-dependent scattering potential. Previously it is found that Fano resonance occurs as a result of energy matching in one-dimensional systems. In this work, we demonstrate that when transverse motion is present, Fano resonance occurs precisely at the wavevector matching situation. Using the Floquet scattering theory, we considered the transport properties of a nonadiabatic time-dependent well both in a two-dimensional electron gas and monolayer graphene structure. Dispersion of the quasibound state of a static quantum well is obtained with transverse motion present. We found that Fano resonance occurs when the wavevector in the transport direction of one of the Floquet sidebands is exactly identical to that of the quasibound state in the well at equilibrium and follows the dispersion pattern of the latter. To observe the Fano resonance phenomenon in the transmission spectrum, we also considered the pumped shot noise properties when time and spatial symmetry secures vanishing current in the considered configuration. Prominent Fano resonance is found in the differential pumped shot noise with respect to the reservoir Fermi energy.

  15. Arbitrary tunable spaser based on double-Fano resonance of two sets of disk-ring nanostructure

    CERN Document Server

    Huo, Y; Zheng, C; Zhao, H; Jiang, S; Ning, T; Yang, C; Tan, C; Jiao, Y; Man, B

    2015-01-01

    This paper demonstrates an arbitrary tunable spaser based on double-Fano resonance of a plasmonic nanostructure consisting of two sets of disk-ring (TSDR) nanostructure. TSDR nanostructure supports two Fano resonances, which can be served as the lasing mode and the pumping mode of a spaser. These two mode can be tuned in a very wide wavelength range because of the good tunability of the two nanorings. The tuning range of the lasing mode and the pumping mode can be reached to 710 nm and 620 nm. These results represent a significant step in the pursuit of ultimate spasers and propose a approach to manipulate lasing mode and pumping mode over a broad spectral range.

  16. Fano-resonance boosted cascaded field enhancement in a plasmonic nanoparticle-in-cavity nanoantenna array and its SERS application

    CERN Document Server

    Zhu, Zhendong; You, Oubo; Li, Qunqing; Fan, Shoushan

    2015-01-01

    Cascaded optical field enhancement (CFE) can be realized in some specially designed multiscale plasmonic nanostructures, where the generation of extremely strong field at nanoscale volume is crucial for many applications, for example, surface enhanced Raman spectroscopy (SERS). Here, we propose a strategy of realizing a high-quality plasmonic nanoparticle-in-cavity (PIC) nanoantenna array, where strong coupling between a nanoparticle dark mode with a high order nanocavity bright mode can produce Fano resonance at a target wavelength. The Fano resonance can effectively boost the CFE in the PIC, with a field enhancement factor up to 5X10^2. A cost-effective and reliable nanofabrication method is developed with room temperature nanoimprinting lithography to manufacture high-quality PIC arrays. This technique guarantees the generation of only one gold nanoparticle at the bottom of each nanocavity, which is crucial for the generation of the expected CFE. As a demonstration of the performance and application of the...

  17. Glucose sensing through Fano resonances in mesoscale silica core-gold shell particles arrays

    Science.gov (United States)

    Pincella, Francesca; Huang, Zhiwei

    2016-03-01

    We report the development of a versatile, cheap and reusable plasmonic sensor able to detect glucose in the physiological concentration range by means of a simple label-free optical detection scheme. In order to achieve the aforementioned goal we applied a self-assembly deposition technique for the large-scale arraying of mesoscale gold nanoshell particles. Different from metallic nanospheres arrays, the localized surface plasmon resonances of gold nanoshells arrays extend in both the visible and near-infrared range, making them extremely promising for their use in biological media. Furthermore, the optical response of mesoscale gold nanoshells arrays showed another remarkable characteristic, which is the presence of various Fano resonances that have the advantage of enhancing the sensitivity of the plasmonic substrate to the external media thanks to their sharp features and increased spectral contrast. The plasmonic sensor was shown to have an extended working range with a good linear response for large refractive index shifts, where a bulk refractive index sensitivity of 0.93 RIU-1 (RIU, refractive index units) was achieved experimentally. In addition, the plasmonic sensor could detect aqueous glucose solutions in the blood concentration range (0-25 mM), with a sensitivity of 0.24 M-1.

  18. Fano resonance in asymmetric-period two-dimensional plasmonic absorbers for dual-band uncooled infrared sensors

    Science.gov (United States)

    Ogawa, Shinpei; Takagawa, Yousuke; Kimata, Masafumi

    2016-11-01

    The spectral discrimination function of uncooled infrared (IR) sensors has significant advantages for applications such as fire detection, gas analysis, and biological analysis. We have previously demonstrated wavelength-selective uncooled IR sensors using two-dimensional plasmonic absorbers (2-D PLAs) over a wide range spanning the middle- and long-wavelength IR regions. 2-D PLAs are highly promising in terms of practical application due to the ease of fabrication and robustness for structural fluctuations. However, dual-band operation based on this concept has not yet been investigated, even though the ability to absorb in two different wavelength bands is extremely important for object recognition. Thus, a dual-band uncooled IR sensor was developed that employs Fano resonance in the plasmonic structures. To achieve dual-band detection, asymmetric periods in the orthogonal x- and y-directions were introduced into 2-D PLAs. Theoretical investigations predicted an asymmetric absorbance line shape dependent on the polarization attributed to Fano resonance. The spectral responsivity of the developed sensor demonstrated that selective detection occurred in two different wavelength bands due to polarization-dependent Fano resonance. The results obtained in this study will be applicable to the development of advanced sensors capable of multiband detection in the IR region.

  19. Nonlinear interaction of two trapped-mode resonances in a bilayer "fish-scale" metamaterial

    CERN Document Server

    Tuz, Vladimir R; Mladyonov, Pavel L; Prosvirnin, Sergey L; Novitsky, Andrey V

    2014-01-01

    We report on a bistable light transmission through a bilayer "fish-scale" (meander-line) metamaterial. It is demonstrated that an all-optical switching may be achieved nearly the frequency of the high-quality-factor Fano-shaped trapped-mode resonance excitation. The nonlinear interaction of two closely spaced trapped-mode resonances in the bilayer structure composed with a Kerr-type nonlinear dielectric slab is analyzed in both frequency and time domains. It is demonstrated that these two resonances react differently on the applied intense light which leads to destination of a multistable transmission.

  20. Kondo Resonance versus Fano Interference in Double Quantum Dots Coupled to a Two-Lead One-Ring System

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiong-Wen; SHI Zhen-Gang; CHEN Bao-Ju; SONG Ke-Hui

    2007-01-01

    We analyse the transport properties of a coupled double quantum dot (DQD) device with one of the dots (QD1) coupled to metallic leads and the other (QD2) embedded in an Aharonov-Bhom (A-B) ring by means of the slave-boson mean-Geld theory. It is found that in this system, the Kondo resonance and the Fano interference exist simultaneously, the enhancing Kondo effect and the increasing hopping of the QD2-Ring destroy the localized electron state in the QD2 for the QD1-leads, and accordingly, the Fano interference between the DQD-leads and the QD1-leads are suppressed. Under some conditions, the Fano interference can be quenched fully and the single Kondo resonance of the QD1-leads comes into being. Moreover, when the magnetic flux of the A-B ring is zero, the influence of the parity of the A-B ring on the transport properties is very weak, but this inSuence becomes more obvious with non-zero magnetic flux. Thus this model may be a candidate for future device applications.

  1. Stochastic and equilibrium pictures of the ultracold Fano-Feshbach-resonance molecular conversion rate

    Science.gov (United States)

    Yamakoshi, Tomotake; Watanabe, Shinichi; Zhang, Chen; Greene, Chris H.

    2013-05-01

    The ultracold molecular conversion rate occurring in an adiabatic ramp through a Fano-Feshbach resonance is studied and compared in two statistical models. One model, the so-called stochastic phase-space sampling (SPSS) [Hodby , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.94.120402 94, 120402 (2005)] evaluates the overlap of two atomic distributions in phase space by sampling atomic pairs according to a phase-space criterion. The other model, the chemical equilibrium theory (ChET) [Watabe and Nikuni, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.77.013616 77, 013616 (2008)] considers atomic and molecular distributions in the limit of the chemical and thermal equilibrium. The present study applies SPSS and ChET to a prototypical system of K+K→ K2 in all the symmetry combinations, namely Fermi-Fermi, Bose-Bose, and Bose-Fermi cases. To examine implications of the phase-space criterion for SPSS, the behavior of molecular conversion is analyzed using four distinct geometrical constraints. Our comparison of the results of SPSS with those of ChET shows that while they appear similar in most situations, the two models give rise to rather dissimilar behaviors when the presence of a Bose-Einstein condensate strongly affects the molecule formation.

  2. Fano-resonance induced strong-coupling of a hyperbolic cavity to a quantum emitter

    CERN Document Server

    Hasan, Mehedi; Belov, Pavel

    2015-01-01

    Light-matter interaction is studied for an open quantum system in the strong-coupling regime. A quantum dot and a hyperbolic cavity of spherical geometry is shown to couple light with large Rabi frequency and the role of Fano resonance is shown in the coupling mechanism. High Purcell factor and large Lamb shift are outlined. In the near-field spectrum, two distinct anti-crossings are evident, namely -- the one near the epsilon near zero (ENZ) frequency (from the effective medium description) which is detectable in the far-field, and the second anti-crossing is a pseudomode that does not appear in the far-field spectrum. This delineates the phenomenon `farfield propagating large Purcell factor'. Finally, we remark the fidelity of the strong-coupling, i.e. how prone the strong-coupling with respect to the loss mechanisms. This study on strong-coupling will have applications for spectroscopy, control over chemical reaction rate, microcavity, and in quantum information technology.

  3. Fano resonance and hybridization gap in the Kondo lattice URu2Si2^*

    Science.gov (United States)

    Park, Wan Kyu; Tobash, P. H.; Ronning, F.; Bauer, E. D.; Sarrao, J. L.; Thompson, J. D.; Greene, L. H.

    2012-02-01

    The nature of the `hidden' order transition in URu2Si2 remains puzzling despite intensive research over the past two and half decades. A key question under debate is whether a hybridization gap between the renormalized bands can be identified as the long-sought hidden order parameter. We report on the measurement of a hybridization gap in URu2Si2 employing a spectroscopic technique based on quasiparticle scattering across a ballistic metallic junction [1]. The differential conductance data exhibit an asymmetric double-peak structure, a signature for a Fano resonance in a Kondo lattice [2]. The extracted hybridization gap opens well above the hidden order transition temperature, indicating that it is not the order parameter for the hidden order phase. Our results place constraints on the origin of the hidden order transition in URu2Si2.[4pt] [1] W. K. Park et al., arXiv:1110.5541.[0pt] [2] M. Maltseva, M. Dzero, P. Coleman, PRL 103, 206402 (2009).

  4. Fano resonances in Majorana bound states-quantum dot hybrid systems

    Science.gov (United States)

    Schuray, Alexander; Weithofer, Luzie; Recher, Patrik

    2017-08-01

    We consider a quantum wire containing two Majorana bound states (MBS) at its ends that are tunnel-coupled to a current lead on one side and to a quantum dot (QD) on the other side. Using the method of full counting statistics we calculate the conductance and the zero-frequency noise. Using an effective low-energy model, we analyze in detail the Andreev reflection probability as a function of the various system parameters and show that it exhibits a Fano resonance (FR) line shape in the case of a weakly coupled QD as a function of the QD energy level when the two MBS overlap. The asymmetry parameter changes sign as the bias voltage is tuned through the MBS overlap energy. The FR is mirrored as a function of the QD level energy as long as tunneling from the dot to the more distant MBS is negligible. However, if both MBS are coupled to the lead and the QD, the height as well as the asymmetry of the line shapes cease to respect this symmetry. These two exclusive cases uniquely distinguish the coupling to a MBS from the coupling to a fermionic bound state that is shared between the two MBS. We complement the analysis by employing a discretized one-dimensional p -wave superconductor (Kitaev chain) for the quantum wire and show that the features of the effective low-energy model are robust towards a more complete Hamiltonian and also persist at finite temperature.

  5. Beating oscillation and Fano resonance in the laser assisted electron transmission through graphene δ-function magnetic barriers

    Science.gov (United States)

    Biswas, R.; Maity, S.; Sinha, C.

    2016-10-01

    We investigate theoretically the transmission of electrons through a pair of δ-function magnetic barriers in graphene in presence of external monochromatic, linearly polarized and CW laser field. The transmission coefficients are calculated in the framework of non-perturbative Floquet theory using the transfer matrix method. It is noted that the usual Fabry-Perot oscillations in transmission through the graphene magnetic barriers with larger inter barrier separation takes the shape of beating oscillations in presence of the external laser field. The laser assisted transmission spectra are also found to exhibit the characteristic Fano resonances (FR) for smaller values of the inter barrier separation. The appearance of the perfect node in the beating oscillation and the asymmetric Fano line shape can be controlled by varying the intensity of the laser field. The above features could provide some useful and potential information about the light - matter interactions and may be utilized in the graphene based optoelectronic device applications.

  6. Spin-dependent Breit-Wigner and Fano resonances in photon-assisted electron transport through a semiconductor heterostructure

    Institute of Scientific and Technical Information of China (English)

    Hu Li-Yun; Zhou Bin

    2011-01-01

    We theoretically investigate the electron transmission through a seven-layer semiconductor heterostructure with the Dresselhaus spin-orbit coupling under two applied oscillating fields. Numerical results show that both of the spindependent symmetric Breit-Wigner and the asymmetric Fano resonances appear and that the properties of these two types of resonance peaks are dependent on the amplitude and the relative phases of the two applied oscillating fields.The modulation of the spin-polarization efficiency of transmitted electrons by the relative phase is also discussed.

  7. Fano resonant Ge2Sb2Te5 nanoparticles realize switchable lateral optical force

    Science.gov (United States)

    Cao, Tun; Mao, Libang; Gao, Dongliang; Ding, Weiqiang; Qiu, Cheng-Wei

    2016-03-01

    Sophisticated optical micromanipulation of small biomolecules usually relies on complex light, e.g., structured light, highly non-paraxial light, or chiral light. One emerging technique is to employ chiral light to drive the chiral nanoparticle along the direction perpendicular to the propagation of the light, i.e., the lateral optical force. Here, we theoretically study the lateral optical force exerted by a entirely Gaussian beam. For the very first time we demonstrate that the Fano resonances (FRs) of the Ge2Sb2Te5 (GST) phase-change nanoparticles encapsulated with Au shells could enable a conventional Gaussian laser to exert a lateral force on such a dielectric GST nanoparticle, attributed to the strongly asymmetric energy flow around the sphere in the dipole-quadrupole FRs. More interestingly, the direction of this lateral force could be reversible during the state transition (i.e., from amorphous to crystalline). By bonding small biomolecules to the outer surface of the phase-change nanoparticle, the particle behaves as a direction-selective vehicle to transport biomolecules along opposite directions, at pre-assessed states of the Ge2Sb2Te5 core correspondingly. Importantly, the origin of the reversal of the lateral optical force is further unveiled by the optical singularity of the Poynting vector. Our mechanism of tailoring the FRs of phase-change nanoparticles, not just limited to GST, may bring a new twist to optical micromanipulation and biomedical applications.Sophisticated optical micromanipulation of small biomolecules usually relies on complex light, e.g., structured light, highly non-paraxial light, or chiral light. One emerging technique is to employ chiral light to drive the chiral nanoparticle along the direction perpendicular to the propagation of the light, i.e., the lateral optical force. Here, we theoretically study the lateral optical force exerted by a entirely Gaussian beam. For the very first time we demonstrate that the Fano resonances

  8. Demonstration of a self-pulsing photonic crystal Fano laser

    CERN Document Server

    Yu, Yi; Semenova, Elizaveta; Yvind, Kresten; Mork, Jesper

    2016-01-01

    Semiconductor lasers in use today rely on mirrors based on the reflection at a cleaved facet or Bragg reflection from a periodic stack of layers. Here, we demonstrate an ultra-small laser with a mirror based on the Fano resonance between a continuum of waveguide modes and the discrete resonance of a nanocavity. The Fano resonance leads to unique laser characteristics. Since the Fano mirror is very narrow-band compared to conventional lasers, the laser is single-mode and in particular, it can be modulated via the mirror. We show, experimentally and theoretically, that nonlinearities in the mirror may even promote the generation of a self-sustained train of pulses at gigahertz frequencies, an effect that was previously only observed in macroscopic lasers. Such a source is of interest for a number of applications within integrated photonics.

  9. Universal lineshapes at the crossover between weak and strong critical coupling in Fano-resonant coupled oscillators

    CERN Document Server

    Zanotto, Simone

    2015-01-01

    In this article we discuss a model describing key features concerning the lineshapes and the coherent absorption conditions in Fano-resonant dissipative coupled oscillators. The model treats on the same footing the weak and strong coupling regimes, and includes the critical coupling concept, which is of great relevance in numerous applications; in addition, the role of asymmetry is thoroughly analyzed. Due to the wide generality of the model, which can be adapted to various frameworks like nanophotonics, plasmonics, and optomechanics, we envisage that the analytical formulas presented here will be crucial to effectively design devices and to interpret experimental results.

  10. Modeling and experimental investigations of Fano resonances in free-standing LiNbO3 photonic crystal slabs.

    Science.gov (United States)

    Deng, Jun; Hussain, Sajid; Kumar, Vanga Sudheer; Jia, Wei; Png, Ching Eng; Thor, Lim Soon; Bettiol, Andrew A; Danner, Aaron J

    2013-02-11

    In this paper the Fano resonance in a free-standing LiNbO(3) photonic crystal slab is demonstrated. We present a numerical analysis and experimental measurements with free space illumination where the dependence of slab thickness, radius of air holes and lattice types are investigated. The unique property of polarization dependence for LiNbO(3) photonic crystal slabs is also analyzed, and we show that the transmission spectra exhibit significant sensitivity (~25nm) to polarization. A monolithic free-standing LiNbO(3) photonic crystal slab was fabricated using ion beam enhanced etching (IBEE) technology. Measurement results of the reflection spectra agree with the numerical analysis.

  11. Nonlinear optical spectra having characteristics of Fano interferences in coherently coupled lowest exciton biexciton states in semiconductor quantum dots

    Directory of Open Access Journals (Sweden)

    Hideki Gotoh

    2014-10-01

    Full Text Available Optical nonlinear effects are examined using a two-color micro-photoluminescence (micro-PL method in a coherently coupled exciton-biexciton system in a single quantum dot (QD. PL and photoluminescence excitation spectroscopy (PLE are employed to measure the absorption spectra of the exciton and biexciton states. PLE for Stokes and anti-Stokes PL enables us to clarify the nonlinear optical absorption properties in the lowest exciton and biexciton states. The nonlinear absorption spectra for excitons exhibit asymmetric shapes with peak and dip structures, and provide a distinct contrast to the symmetric dip structures of conventional nonlinear spectra. Theoretical analyses with a density matrix method indicate that the nonlinear spectra are caused not by a simple coherent interaction between the exciton and biexciton states but by coupling effects among exciton, biexciton and continuum states. These results indicate that Fano quantum interference effects appear in exciton-biexciton systems at QDs and offer important insights into their physics.

  12. Nonlinear behavior of Helmholtz resonators

    Science.gov (United States)

    Hersh, A. S.

    1990-10-01

    A semi-empirical fluid mechanical model has been derived to predict the nonlinear acoustic behavior of thin-walled, single-orifice Helmholtz resonators. The model assumed that the sound particle velocity field approaches the resonator in a spherically symmetric manner. The incident and cavity sound pressure fields are connected in terms of an orifice discharge coefficient and an end correction parameter whose values are determined empirically. The accuracy of the model was verified by comparing predicted with measured impedance over a wide range of sound amplitudes and frequencies for two different resonator geometries and with measurements conducted by Ingard and Ising.

  13. Nanoscale nonlinear PANDA ring resonator

    CERN Document Server

    Yupapin, Preecha

    2012-01-01

    Microring/nanoring resonator is an interesting device that has been widely studied and investigated by researchers from a variety of specializations. This book begins with the basic background of linear and nonlinear ring resonators. A novel design of nano device known as a PANDA ring resonator is proposed. The use of the device in the form of a PANDA in applications such as nanoelectronics, measurement, communication, sensors, optical and quantum computing, drug delivery, hybrid transistor and a new concept of electron-hole pair is discussed in detail.

  14. Tunable angle-independent refractive index sensor based on Fano resonance in integrated metal and graphene nanoribbons

    Science.gov (United States)

    Pan, Meiyan; Liang, Zhaoxing; Wang, Yu; Chen, Yihang

    2016-07-01

    We propose a novel mechanism to construct a tunable and ultracompact refractive index sensor by using the Fano resonance in metal-graphene hybrid nanostructure. Plasmon modes in graphene nanoribbons and waveguide resonance modes in the slits of metal strip array coexist in this system. Strong interference between the two different modes occurs when they are spectrally overlapped, resulting in a Fano-type asymmetrically spectral lineshape which can be used for detecting the variations of ambient refractive index. The proposed sensor has a relatively high figure of merit (FOM) over 20 and its sensing performance shows a good tolerance to roughness. In addition to the wide range measurement enabled by the electrical tuning of graphene plasmon modes, such ultracompact system also provides an angle-independent operation and therefore, it can efficiently work for the detection of gas, liquid, or solids. Such optical nanostructure may also be applied to diverse fields such as temperature/pressure metering, medical detection, and mechanical precision measurement.

  15. Resonant tunneling and nonlinear current in heterobarrier with complex dispersion of carriers

    CERN Document Server

    Kim, C S; Shtenberg, V B

    2002-01-01

    The study of novel effects in resonant tunneling of electrons in GaAs/Al sub x Ga sub 1 sub - sub x As/GaAs single-barrier structures under an applied electric bias is carried out. GAMMA-X mixing of electron states at the interfaces is responsible for Fano resonance in the barrier transmittance. A motion of Fano resonances and the interaction between Fano and Breit-Wigner resonances in electric field have been investigated. The current-voltage characteristic of the heterobarrier is calculated. It is shown that the differential conductivity presents a way to get the Fano resonance profile and its parameters

  16. Inductive tuning of Fano-resonant metasurfaces using plasmonic response of graphene in the mid-infrared.

    Science.gov (United States)

    Mousavi, S Hossein; Kholmanov, Iskandar; Alici, Kamil B; Purtseladze, David; Arju, Nihal; Tatar, Kaya; Fozdar, David Y; Suk, Ji Won; Hao, Yufeng; Khanikaev, Alexander B; Ruoff, Rodney S; Shvets, Gennady

    2013-03-13

    Graphene is widely known for its anomalously strong broadband optical absorptivity of 2.3% that enables seeing its single-atom layer with the naked eye. However, in the mid-infrared part of the spectrum graphene represents a quintessential lossless zero-volume plasmonic material. We experimentally demonstrate that, when integrated with Fano-resonant plasmonic metasurfaces, single-layer graphene (SLG) can be used to tune their mid-infrared optical response. SLG's plasmonic response is shown to induce large blue shifts of the metasurface's resonance without reducing its spectral sharpness. This effect is explained by a generalized perturbation theory of SLG-metamaterial interaction that accounts for two unique properties of the SLG that set it apart from all other plasmonic materials: its anisotropic response and zero volume. These results pave the way to using gated SLG as a platform for dynamical spectral tuning of infrared metamaterials and metasurfaces.

  17. Asymmetry parameter of peaked Fano line shapes

    Science.gov (United States)

    Meierott, S.; Hotz, T.; Néel, N.; Kröger, J.

    2016-10-01

    The spectroscopic line shape of electronic and vibrational excitations is ubiquitously described by a Fano profile. In the case of nearly symmetric and peaked Fano line shapes, the fit of the conventional Fano function to experimental data leads to difficulties in unambiguously extracting the asymmetry parameter, which may vary over orders of magnitude without degrading the quality of the fit. Moreover, the extracted asymmetry parameter depends on initially guessed values. Using the spectroscopic signature of the single-Co Kondo effect on Au(110) the ambiguity of the extracted asymmetry parameter is traced to the highly symmetric resonance profile combined with the inevitable scattering of experimental data. An improved parameterization of the conventional Fano function is suggested that enables the nonlinear optimization in a reduced parameter space. In addition, the presence of a global minimum in the sum of squared residuals and thus the independence of start parameters may conveniently be identified in a two-dimensional plot. An angular representation of the asymmetry parameter is suggested in order to reliably determine uncertainty margins via linear error propagation.

  18. Analytical determination of Kondo and Fano resonances of electron Green's function in a single-level quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Bich Ha [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Dist., Hanoi (Viet Nam); Nguyen Van Hop [Hanoi National University of Education, Hanoi (Viet Nam)], E-mail: bichha@iop.vast.ac.vn

    2009-09-01

    The Kondo and Fano resonances in the two-point Green's function of the single-level quantum dot were found and investigated in many previous works by means of different numerical calculation methods. In this work we present the derivation of the analytical expressions of resonance terms in the expression of the two-point Green's function. For that purpose the system of Dyson equations for the two-point nonequilibrium Green's functions in the complex-time Keldysh formalism was established in the second order with respect to the tunneling coupling constants and the mean field approximation. This system of Dyson equations was solved exactly and the analytical expressions of the resonance terms are derived. The conditions for the existence of Kondo or Fano resonances are found.

  19. Analytic Elastic Cross Sections for Electron-Atom Scattering from Generalized Fano Profiles of Overlapping Low-Energy Shape Resonances

    CERN Document Server

    Nicoletopoulos, P

    2003-01-01

    The variation with energy of the total cross section for elastic electron scattering from atoms of several elements is caused primarily by shape resonances corresponding to the formation of temporary negative ions. It is shown that such cross sections are expressible analytically in terms of a constant background added to a "generalized Fano profile" [Durand Ph, et al (2001) J. Phys. B: At. Mol. Opt. Phys. 34, 1953, ibid (2002) 35, 469]. In three cases (sodium, magnesium and mercury), a detailed consideration proves that this representation is accurate in a fairly wide energy range. Moreover, the related momentum transfer cross sections are tailor-made for studying "elastic" electron transport in terms of the two-term solution of the Boltzmann equation: Not only are the resulting swarm transport coefficients adjustable to the experimental values, but above all they are calculable very easily because the unnormalized energy distribution is obtainable analytically. The ample saving in computational effort is ex...

  20. Tailoring the negative-refractive-index metamaterials composed of semiconductor-metal-semiconductor gold ring/disk cavity heptamers to support strong Fano resonances in the visible spectrum.

    Science.gov (United States)

    Ahmadivand, Arash; Pala, Nezih

    2015-02-01

    In this study, we investigated numerically the plasmon response of a planar negative-index metamaterial composed of symmetric molecular orientations of Au ring/disk nanocavities in a heptamer cluster. Using the plasmon hybridization theory and considering the optical response of an individual nanocluster, we determined the accurate geometrical sizes for a ring/disk nanocavity heptamer. It is shown that the proposed well-organized nanocluster can be tailored to support strong and sharp Fano resonances in the visible spectrum. Surrounding and filling the heptamer clusters by various metasurfaces with different chemical characteristics, and illuminating the structure with an incident light source, we proved that this configuration reflects low losses and isotropic features, including a pronounced Fano dip in the visible spectrum. Technically, employing numerical methods and tuning the geometrical sizes of the structure, we tuned and induced the Fano dip in the visible range, while the dark and bright plasmon resonance extremes are blueshifted to shorter wavelengths dramatically. Considering the calculated transmission window, we quantified the effective refractive index for the structure, while the substance of the substrate material was varied. Using Si, GaP, and InP semiconductors as substrate materials, we calculated and compared the corresponding figure of merit (FOM) for different regimes. The highest possible FOM was obtained for the GaP-Au-GaP negative-refractive-index metamaterial composed of ring/disk nanocavity heptamers as 62.4 at λ∼690  nm (arounnd the position of the Fano dip). Despite the outstanding symmetric nature of the suggested heptamer array, we provided sharp Fano dips by the appropriate tuning of the geometrical and chemical parameters. This study yields a method to employ ring/disk nanocavity heptamers as a negative-refractive-index metamaterial in designing highly accurate localization of surface plasmon resonance sensing devices and

  1. Interferometric phase detection at x-ray energies via Fano resonance control

    CERN Document Server

    Heeg, K P; Schumacher, D; Wille, H -C; Röhlsberger, R; Pfeifer, T; Evers, J

    2014-01-01

    Modern x-ray light sources promise access to structure and dynamics of matter in largely unexplored spectral regions. However, the desired information is encoded in the light intensity and phase, whereas detectors register only the intensity. This phase problem is ubiquitous in crystallography and imaging, and impedes the exploration of quantum effects at x-ray energies. Here, we demonstrate phase-sensitive measurements characterizing the quantum state of a nuclear two-level system at hard x-ray energies. The nuclei are initially prepared in a superposition state. Subsequently, the relative phase of this superposition is interferometrically reconstructed from the emitted x-rays. Our results form a first step towards x-ray quantum state tomography, and provide new avenues for structure determination and precision metrology via x-ray Fano interference.

  2. Nonlinearity and nonclassicality in a nanomechanical resonator

    Energy Technology Data Exchange (ETDEWEB)

    Teklu, Berihu [Clermont Universite, Blaise Pascal University, CNRS, PHOTON-N2, Institut Pascal, Aubiere Cedex (France); Universita degli Studi di Milano, Dipartimento di Fisica, Milano (Italy); Ferraro, Alessandro; Paternostro, Mauro [Queen' s University, Centre for Theoretical Atomic, Molecular, and Optical Physics, School of Mathematics and Physics, Belfast (United Kingdom); Paris, Matteo G.A. [Universita degli Studi di Milano, Dipartimento di Fisica, Milano (Italy)

    2015-12-15

    We address quantitatively the relationship between the nonlinearity of a mechanical resonator and the nonclassicality of its ground state. In particular, we analyze the nonclassical properties of the nonlinear Duffing oscillator (being driven or not) as a paradigmatic example of a nonlinear nanomechanical resonator. We first discuss how to quantify the nonlinearity of this system and then show that the nonclassicality of the ground state, as measured by the volume occupied by the negative part of the Wigner function, monotonically increases with the nonlinearity in all the working regimes addressed in our study. Our results show quantitatively that nonlinearity is a resource to create nonclassical states in mechanical systems. (orig.)

  3. Nonreciprocal transmission in a nonlinear photonic-crystal Fano structure with broken symmetry

    DEFF Research Database (Denmark)

    Yu, Yi; Chen, Yaohui; Hu, Hao;

    2015-01-01

    Nanostructures that feature nonreciprocal light trans- mission are highly desirable building blocks for realizing photonic integrated circuits. Here, a simple and ultracompact photonic-crystal structure, where a waveguide is coupled to a single nanocavity, is proposed and experimentally demon- st...... tunability. The nonlinearity of the device relies on ultrafast carrier dynamics, rather than the thermal effects usually considered, allowing the demonstration of nonreciprocal operation at a bit-rate of 10 Gbit s − 1 with a low energy consumption of 4.5 fJ bit − 1...

  4. Nonlinear Thermal Compensators for WGM Resonators

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry; Maleki, Lute; Yu, Nan; Iltchenko, Vladimir

    2009-01-01

    In an alternative version of a proposed bimaterial thermal compensator for a whispering-gallery-mode (WGM) optical resonator, a mechanical element having nonlinear stiffness would be added to enable stabilization of a desired resonance frequency at a suitable fixed working temperature. The previous version was described in "Bimaterial Thermal Compensators for WGM Resonators." Both versions are intended to serve as inexpensive means of preventing (to first order) or reducing temperature-related changes in resonance frequencies.

  5. Magnetic-dipolar-mode Fano resonances for microwave spectroscopy of high absorption matter

    CERN Document Server

    Vaisman, G; Shavit, R

    2015-01-01

    Study of interaction between high absorption matter and microwave radiated energy is a subject of great importance. Especially, this concerns microwave spectroscopic characterization of biological liquids. Use of effective testing methods to obtain information about physical properties of different liquids on the molecular level is one of the most important problems in biophysics. However, the standard methods based on the microwave resonant techniques are not sufficiently suitable for biological liquids because the resonance peak in a resonator with high-loss liquids is so broad that the material parameters cannot be measured correctly. Although molecular vibrations of biomolecules may have microwave frequencies, it is not thought that such resonant coupling is significant due to their low energy compared with thermal energy and the strongly dampening aqueous environment. This paper presents an innovative microwave sensing technique for different types of lossy materials, including biological liquids. The te...

  6. Field-assisted electron transport through a symmetric double-well structure with spin-orbit coupling and the Fano-resonance induced spin filtering

    Institute of Scientific and Technical Information of China (English)

    Zhang Cun-Xi; Nie Yi-Hang; Liang Jiu-Qing

    2008-01-01

    We have investigated theoretically the field-driven electron-transport through a double-quantum-well semiconductor-heterostructure with spin-orbit coupling. The numerical results demonstrate that the transmission spectra are divided into two sets due to the bound-state level-splitting and each set contains two asymmetric resonance peaks which may be selectively suppressed by changing the difference in phase between two driving fields. When the phase difference changes from O to π, the dip of asymmetric resonance shifts from one side of resonance peak to the other side and the asymmetric Fano resonance degenerates into the symmetric Breit-Wigner resonance at a critical value of phase difference. Within a given range of incident electron energy, the spin polarization of transmission current is completely governed by the phase difference which may be used to realize the tunable spin filtering.

  7. Time-resolved two-photon photoemission at the Si(001)-surface. Hot electron dynamics and two-dimensional Fano resonance; Zeitaufgeloeste Zweiphotonen-Photoemission an der Si(001)-Oberflaeche. Dynamik heisser Elektronen und zweidimensionaler Fano-Effekt

    Energy Technology Data Exchange (ETDEWEB)

    Eickhoff, Christian

    2010-10-27

    By combining ultrafast laser excitation with energy-, angle- and time-resolved twophoton photoemission (2PPE), the electronic properties of bulk silicon and the Si(001) surface are investigated in this thesis. A custom-built laser- and UHV-systemequipped with a display type 2D-CCD-detector gives new insight into the relaxation dynamics of excited carriers on a femtosecond timescale. The bandgap between occupied valence bands and unoccupied conduction bands characteristically influences the dynamics of excited electrons in the bulk, as well as in surface states and resonances. For the electron-phonon interaction this leads to the formation of a bottleneck during the relaxation of hot electrons in the conduction band, which maintains the elevated electronic temperature for several picoseconds. During relaxation, excited electrons also scatter from the conduction band into the unoccupied dangling-bond surface state D{sub down}. Depending on the excitation density this surface recombination is dominated by electron-electron- or electron-phonon scattering. The relaxation of the carriers in the D{sub down}-band is again slowed down by the formation of a bottleneck in electron-phonon coupling. Furthermore, the new laser system has allowed detection of the Rydberg-like series of image-potential resonances on the Si(001)-surface. It is shown that the lifetime of these image-potential resonances in front of the semiconducting surface exhibits the same behavior as those in front of metallic surfaces. Moreover the electron-phonon coupling in the first image-potential resonance was investigated and compared to the D{sub down}-surface state. For the first time, Fano-type lineprofiles are demonstrated and analyzed in a 2PPEprocess on a surface. Tuning the photon energy of the pump-laser across the resonance between the occupied dangling-bond state D{sub up}, and the unoccupied image-potential resonance n=1, reveals a clear intensity variation that can be successfully described

  8. HTS nonlinearities in microwave disk resonators

    Science.gov (United States)

    Collado, Carlos; Mateu, Jordi; Shaw, Timothy J.; O'Callaghan, Juan M.

    2002-08-01

    This article describes a procedure for the calculation of the intermodulation behavior of the TM0 1 0 mode in high temperature superconducting (HTS) disk resonators from a description of the local HTS nonlinearities. Successful cross-checks are performed by comparing the theoretical results with experimental measurements and simulations based on the multiport harmonic balance algorithm for a specific model of HTS nonlinearity. The application of this procedure to the determination of nonlinear material parameters from disk resonator measurements is illustrated and compared to theoretical predictions.

  9. Tunable Resonators for Nonlinear Modal Interactions

    KAUST Repository

    Ramini, Abdallah

    2016-10-04

    Understanding the various mechanisms of nonlinear mode coupling in micro and nano resonators has become an imminent necessity for their successful implementation in practical applications. However, consistent, repeatable, and flexible experimental procedures to produce nonlinear mode coupling are lacking, and hence research into well-controlled experimental conditions is crucial. Here, we demonstrate well-controlled and repeatable experiments to study nonlinear mode coupling among micro and nano beam resonators. Such experimental approach can be applied to other micro and nano structures to help study their nonlinear interactions and exploit them for higher sensitive and less noisy responses. Using electrothermal tuning and electrostatic excitation, we demonstrate three different kinds of nonlinear interactions among the first and third bending modes of vibrations of slightly curved beams (arches): two-one internal resonance, three-one internal resonance, and mode veering (near crossing). The experimental procedure is repeatable, highly flexible, do not require special or precise fabrication, and is conducted in air and at room temperature. This approach can be applied to other micro and nano structures, which come naturally curved due to fabrication imperfections, such as CNTs, and hence lays the foundation to deeply investigate the nonlinear mode coupling in these structures in a consistent way.

  10. Tunable Resonators for Nonlinear Modal Interactions

    Science.gov (United States)

    Ramini, Abdallah H.; Hajjaj, Amal Z.; Younis, Mohammad I.

    2016-10-01

    Understanding the various mechanisms of nonlinear mode coupling in micro and nano resonators has become an imminent necessity for their successful implementation in practical applications. However, consistent, repeatable, and flexible experimental procedures to produce nonlinear mode coupling are lacking, and hence research into well-controlled experimental conditions is crucial. Here, we demonstrate well-controlled and repeatable experiments to study nonlinear mode coupling among micro and nano beam resonators. Such experimental approach can be applied to other micro and nano structures to help study their nonlinear interactions and exploit them for higher sensitive and less noisy responses. Using electrothermal tuning and electrostatic excitation, we demonstrate three different kinds of nonlinear interactions among the first and third bending modes of vibrations of slightly curved beams (arches): two-one internal resonance, three-one internal resonance, and mode veering (near crossing). The experimental procedure is repeatable, highly flexible, do not require special or precise fabrication, and is conducted in air and at room temperature. This approach can be applied to other micro and nano structures, which come naturally curved due to fabrication imperfections, such as CNTs, and hence lays the foundation to deeply investigate the nonlinear mode coupling in these structures in a consistent way.

  11. Signature of a Fano-resonance in a plasmonic meta-molecule's local density of optical states

    CERN Document Server

    Frimmer, Martin; Koenderink, A Femius

    2011-01-01

    We present measurements on plasmonic meta-molecules under local excitation using cathodoluminescence which show a spatial redistribution of the local density of optical states (LDOS) at the same frequency where a sharp spectral Fano-feature in the extinction cross section has been observed. Our analytical model shows that both near- and far-field effects arise due to interference of the same two eigenmodes of the system. We present quantitative insights both in a bare state, and in a dressed state picture that describe plasmonic Fano interference either as near-field amplitude transfer between three coupled bare states, or as interference of two uncoupled eigenmodes in the far field. We identify the same eigenmode causing a dip in extinction to strongly enhance the radiative LDOS, making it a promising candidate for spontaneous emission control.

  12. Nonlinearity and hysteresis of resonant strain gauges

    NARCIS (Netherlands)

    Gui, Chengqun; Legtenberg, Rob; Tilmans, Harrie A.C.; Fluitman, Jan H.J; Elwenspoek, Miko

    1995-01-01

    Nonlinearity and hysteresis effects of electrostatically activated, voltage driven resonant microbridges have been studied theoretically and experimentally. It is shown, that, in order to avoid vibration instability and hysteresis to occur, the choices of the ax. and d.c. driving voltages and of the

  13. Nonlinearity and hysteresis of resonant strain gauges

    NARCIS (Netherlands)

    Gui, Chengqun; Legtenberg, Rob; Tilmans, Harrie A.C.; Fluitman, Jan H.J; Elwenspoek, Miko

    1998-01-01

    The nonlinearity and hysteresis effects of the electrostatically activated voltage-driven resonant microbridges have been studied theoretically and experimentally. It is shown that in order to avoid vibration instability and hysteresis to occur, the choices of the ac and dc driving voltages and of t

  14. Nonlinear Resonance of Mechanically Excited Sessile Drops

    Science.gov (United States)

    Chang, Chun-Ti; Daniel, Susan; Steen, Paul

    2013-11-01

    The spectrum of frequencies and mode shapes for an inviscid drop on a planar substrate have recently been documented. For vertical excitation, zonal modes respond to the driving frequency harmonically and non-zonal modes subharmonically, consistent with the prior literature. In this study, we report observations from the regime of nonlinear response. Here, zonals can respond non-harmonically, both sub- and super-harmonic responses are reported. The principal challenge to generating and observing superharmonic resonances of higher zonal modes is a mode-mixing behavior. However, using a simple visual simulation based on the ray-tracing technique, the individual contributions to the mixed resonance behavior can be extracted. In summary, results from experiment and theory show that the zonal modes, which respond harmonically and can mix with non-zonal modes without interfering with one another in the linear regime, tend to respond sub- or superharmonically and compete with non-zonal modes in the nonlinear regime.

  15. Nonlinear nanomechanical resonators for quantum optoelectromechanics

    CERN Document Server

    Rips, S; Hartmann, M J

    2012-01-01

    We present a scheme for enhancing the anharmonicity of nanomechanical resonators by subjecting them to inhomogenous electrostatic fields. We show that this approach enables access to a novel regime of optomechanics, where the nonlinearity per quanta of the mechanical motion becomes comparable to the linewidth of the optical cavities employed. In this "resolved nonlinearity regime" transitions between phonon Fock states of the mechanical resonator can be selectively addressed. As one application we show that our approach would allow to prepare stationary phonon Fock states in experimentally realistic devices. Such states are manifestly non-classical as they show pronounced negative Wigner functions. We calculate the mechanical steady state by tracing out the cavity modes in the weak optomechanical coupling limit and corroborate our results by a numerical analysis of the full dynamics including the cavity modes. Finally, we show how the negativity of the stationary states' Wigner function can be read off the ou...

  16. Optomechanical response of a nonlinear mechanical resonator

    Science.gov (United States)

    Shevchuk, Olga; Singh, Vibhor; Steele, Gary A.; Blanter, Ya. M.

    2015-11-01

    We investigate theoretically in detail the nonlinear effects in the response of an optical/microwave cavity coupled to a Duffing mechanical resonator. The cavity is driven by a laser at a red or blue mechanical subband, and a probe laser measures the reflection close to the cavity resonance. Under these conditions, we find that the cavity exhibits optomechanically induced reflection (OMIR) or absorption (OMIA) and investigate the optomechanical response in the limit of nonlinear driving of the mechanics. Similar to linear mechanical drive, in an overcoupled cavity the red sideband drive may lead to both OMIA and OMIR depending on the strength of the drive, whereas the blue sideband drive only leads to OMIR. The dynamics of the phase of the mechanical resonator leads to the difference between the shapes of the response of the cavity and the amplitude response of the driven Duffing oscillator, for example, at weak red sideband drive the OMIA dip has no inflection point. We also verify that mechanical nonlinearities beyond Duffing model have little effect on the size of the OMIA dip though they affect the width of the dip.

  17. Nonlinear Oscillations of Microscale Piezoelectric Resonators and Resonator Arrays

    Science.gov (United States)

    2006-06-30

    linear characteristics [2-5]. These characteristics include DUffing oscillator like response during resonance excitations [6], temporal harmonics in the...model is used with a single-mode approximation to produce a forced Duffing oscillator . Nonlinear analysis is used to obtain the frequency-response...backward this procedure, the simplified model takes the form of a forced frequency sweeps, only the forward sweep data are used in Duffing oscillator , shown

  18. Nonlinearly Coupled Superconducting Lumped Element Resonators

    Science.gov (United States)

    Collodo, Michele C.; Potočnik, Anton; Rubio Abadal, Antonio; Mondal, Mintu; Oppliger, Markus; Wallraff, Andreas

    We study SQUID-mediated tunable coupling between two superconducting on-chip resonators in the microwave frequency range. In this circuit QED implementation, we employ lumped-element type resonators, which consist of Nb thin film structured into interdigitated finger shunt capacitors and meander inductors. A SQUID, functioning as flux dependent and intrinsically nonlinear inductor, is placed as a coupling element together with an interdigitated capacitor between the two resonators (cf. A. Baust et al., Phys Rev. B 91 014515 (2015)). We perform a spectroscopic measurement in a dilution refrigerator and find the linear photon hopping rate between the resonators to be widely tunable as well as suppressible for an appropriate choice of parameters, which is made possible due to the interplay of inductively and capacitively mediated coupling. Vanishing linear coupling promotes nonlinear effects ranging from onsite- to cross-Kerr interaction. A dominating cross-Kerr interaction related to this configuration is notable, as it induces a unique quantum state. In the course of analog quantum simulations, such elementary building blocks can serve as a precursor for more complex geometries and thus pave the way to a number of novel quantum phases of light

  19. Nonlinear plasmonic resonances in graphene nanostructures

    Science.gov (United States)

    You, Jian Wei; Weismann, Martin; Panoiu, Nicolae C.

    2016-09-01

    Peculiar physical properties of graphene offer remarkable potential for advanced photonics, particularly in the area of nonlinear optics at deep-subwavelength scale. In this article, we use a theoretical and computational analysis to demonstrate an efficient mechanism for enhancing the third-harmonic generation in graphene diffraction gratings. By taking advantage of the relation between the resonance wavelength of localized surface-plasmon polaritons of graphene ribbons and disks their specific geometry, we can engineer the spectral response of graphene gratings so as strong plasmonic resonances exist at both the fundamental frequency and third-harmonic (TH). As a result of this dual resonance mechanism for optical near-field enhancement, the intensity of the TH can be increased greatly.

  20. Dynamic nonlinear thermal optical effects in coupled ring resonators

    Directory of Open Access Journals (Sweden)

    Chenguang Huang

    2012-09-01

    Full Text Available We investigate the dynamic nonlinear thermal optical effects in a photonic system of two coupled ring resonators. A bus waveguide is used to couple light in and out of one of the coupled resonators. Based on the coupling from the bus to the resonator, the coupling between the resonators and the intrinsic loss of each individual resonator, the system transmission spectrum can be classified by three different categories: coupled-resonator-induced absorption, coupled-resonator-induced transparency and over coupled resonance splitting. Dynamic thermal optical effects due to linear absorption have been analyzed for each category as a function of the input power. The heat power in each resonator determines the thermal dynamics in this coupled resonator system. Multiple “shark fins” and power competition between resonators can be foreseen. Also, the nonlinear absorption induced thermal effects have been discussed.

  1. Numerical study of transient nonlinear harbor resonance

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    It is generally accepted that nonlinear wave-wave interactions play an important role in harbor resonance. Nevertheless it is not clear how waves take part in those interactions. The aim of this paper is to investigate those processes for a rectangular harbor at transient phases. Long-period oscillations excited by bichromatic waves are simulated by the Boussinesq model. The simulations start from calm conditions for the purpose of studying the response process. The internal wavemaker stops working after the oscillations have reached a quasi-steady state, and it is used to simulate the damp process. In order to analyze temporary features of wave-wave interactions in different states, the wavelet-based bispectrum is employed. The influence of the short wave frequencies on long-period oscillations is investigated, and reasons are tried to be given from nonlinear triad interactions between different wave components and the interaction of short waves and the bay entrance. Finally, the response time and the damp time are estimated by a simple method.

  2. Molecular detection by active Fano-sensor

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Yifei; Guo, Zhongyi [School of Computer and Information, Hefei University of Technology, Hefei, 230009 (China)

    2017-04-15

    The optical properties and sensing performances of the molecular sensors based on plasmonic Fano-resonance (PFR) nanostructures have been numerically investigated in detail. The on-resonance sensor, in which the Fano-resonance position is overlapping with the absorption-band of the detected molecules perfectly, reveals a powerful ability to detect the molecules with a low concentration or thin thickness. By the bias-modulation of a single-layer graphene, the Fano-resonance position of the nanostructures can be tuned effectively. On being modulated properly, the PFR sensor shows an ultrahigh performance because of the unprecedentedly high overlap of the Fano-resonance position with the absorption-band of molecules, which is enabling superior signal strength in the molecular detections based on their vibrational fingerprints. Our proposed strategy may enable the development of dynamic sensors and open exciting prospects for bio-sensing. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Evidence of the Fano resonance in a temperature dependent Raman study of CaCu3Ti4O12 and SrCu3Ti4O12.

    Science.gov (United States)

    Mishra, Dileep K; Sathe, V G

    2012-06-27

    Phononic excitations have been investigated using Raman scattering studies on CaCu(3)Ti(4)O(12) and SrCu(3)Ti(4)O(12) compounds as a function of temperature down to 10 K. Evidence of the Fano resonance effect is found in the A(g)(1) mode with an asymmetric phonon line shape that occurs because of composite electron-phonon scattering due to the onset of metallic fractions in the system. The evolution of the Fano line shape with temperature affirms the existence of nanoscale phase separation and the prominence of orbitally disrupted metallic regions above 100 K. Anomalies in the evolution of the line width of the A(g)(1) Raman mode with temperature are observed around 100 K where these compounds show an orbital order/disorder transition. These anomalies manifest mutual coupling of orbital degrees of freedom to lattice degrees of freedom.

  4. Parametric Symmetry Breaking in a Nonlinear Resonator

    Science.gov (United States)

    Leuch, Anina; Papariello, Luca; Zilberberg, Oded; Degen, Christian L.; Chitra, R.; Eichler, Alexander

    2016-11-01

    Much of the physical world around us can be described in terms of harmonic oscillators in thermodynamic equilibrium. At the same time, the far-from-equilibrium behavior of oscillators is important in many aspects of modern physics. Here, we investigate a resonating system subject to a fundamental interplay between intrinsic nonlinearities and a combination of several driving forces. We have constructed a controllable and robust realization of such a system using a macroscopic doubly clamped string. We experimentally observe a hitherto unseen double hysteresis in both the amplitude and the phase of the resonator's response function and present a theoretical model that is in excellent agreement with the experiment. Our work unveils that the double hysteresis is a manifestation of an out-of-equilibrium symmetry breaking between parametric phase states. Such a fundamental phenomenon, in the most ubiquitous building block of nature, paves the way for the investigation of new dynamical phases of matter in parametrically driven many-body systems and motivates applications ranging from ultrasensitive force detection to low-energy computing memory units.

  5. A dynamically-tunable graphene-based fano metasurface

    KAUST Repository

    Amin, Muhammad

    2013-09-01

    A planar graphene metasurface with rectangular holes, which is capable of supporting a dynamically tunable Fano resonance at Terahertz (THz) frequencies, is proposed. The rectangular hole is patterned asymmetrically within the metasurface\\'s unit cell to \\'brighten\\' an originally-dark quadrupolar surface plasmon mode. Fano resonance is achieved via the destructive interference of this mode with a dipolar surface plasmon. The spectral location and line shape of the Fano resonance can be dynamically tuned via a gate voltage applied to the metasurface to change graphene\\'s optical properties. The dynamic tunability of the Fano resonance suggests the applicability of the proposed metasurface in designing THz wave modulators and band-pass filters. © 2013 IEEE.

  6. Towards chains of tunable and nonlinear superconducting microwave resonators

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Michael; Wulschner, Friedrich; Schaumburger, Udo; Haeberlein, Max; Fedorov, Kirill; Goetz, Jan; Xie, Edwar [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Schwarz, Manuel; Eder, Peter; Menzel, Edwin; Zhong, Ling; Deppe, Frank; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany)

    2015-07-01

    We present an experimental feasibility study of chains of tunable and nonlinear superconducting microwave resonators within the realm of circuit QED. We describe the fabrication and experimental characterization of the components required to realize nonlinear resonators with tunable anharmonicity, capacitively coupled resonator chains and on-chip parallel plate capacitors. We discuss possible error sources in the fabrication and characterization processes. Furthermore, simulations based on existing theories are performed to identify accessible parameter ranges.

  7. Tunable nonlinear graphene metasurfaces

    CERN Document Server

    Smirnova, Daria A; Kivshar, Yuri S; Khanikaev, Alexander B

    2015-01-01

    We introduce the concept of nonlinear graphene metasurfaces employing the controllable interaction between a graphene layer and a planar metamaterial. Such hybrid metasurfaces support two types of subradiant resonant modes, asymmetric modes of structured metamaterial elements ("metamolecules") and graphene plasmons exhibiting strong mutual coupling and avoided dispersion crossing. High tunability of graphene plasmons facilitates strong interaction between the subradiant modes, modifying the spectral position and lifetime of the associated Fano resonances. We demonstrate that strong resonant interaction, combined with the subwavelength localization of plasmons, leads to the enhanced nonlinear response and high efficiency of the second-harmonic generation.

  8. Nonlinear spectroscopy of superconducting anharmonic resonators

    CERN Document Server

    DiVincenzo, David P

    2011-01-01

    We formulate a model for the steady state response of a nonlinear quantum oscillator structure, such as those used in a variety of superconducting qubit experiments, when excited by a steady, but not necessarily small, ac tone. We show that this model can be derived directly from a circuit description of some recent qubit experiments in which the state of the qubit is read out directly, without a SQUID magnetometer. The excitation profile has a rich structure depending on the detuning of the tone from the small-signal resonant frequency, on the degree of damping, and on the excitation amplitude. We explore two regions in detail: First, at high damping there is a trough in the excitation response as a function of detuning, near where the classical Duffing bifurcation occurs. This trough has been understood as a classical interference between two metastable responses with opposite phase. We use Wigner function studies to show that while this picture is roughly correct, there are also more quantum mechanical asp...

  9. Birationally rigid Fano hypersurfaces

    Energy Technology Data Exchange (ETDEWEB)

    Pukhlikov, A V [Steklov Mathematical Institute, Russian Academy of Sciences (Russian Federation)

    2002-12-31

    We prove that a smooth Fano hypersurface V=V{sub M} subset of P{sup M}, M{>=}6, is birationally superrigid. In particular, it cannot be fibred into uniruled varieties by a non-trivial rational map, and every birational map of V onto a minimal Fano variety of the same dimension is a biregular isomorphism. The proof is based on the method of maximal singularities combined with the connectedness principle of Shokurov and Kollar.

  10. Tailoring the nonlinear response of MEMS resonators using shape optimization

    DEFF Research Database (Denmark)

    Li, Lily L.; Polunin, Pavel M.; Dou, Suguang

    2017-01-01

    We demonstrate systematic control of mechanical nonlinearities in micro-electromechanical (MEMS) resonators using shape optimization methods. This approach generates beams with non-uniform profiles, which have nonlinearities and frequencies that differ from uniform beams. A set of bridge-type mic......We demonstrate systematic control of mechanical nonlinearities in micro-electromechanical (MEMS) resonators using shape optimization methods. This approach generates beams with non-uniform profiles, which have nonlinearities and frequencies that differ from uniform beams. A set of bridge...

  11. Fano interference governs wave transport in disordered systems.

    Science.gov (United States)

    Poddubny, Alexander N; Rybin, Mikhail V; Limonov, Mikhail F; Kivshar, Yuri S

    2012-06-26

    Light localization in disordered systems and Bragg scattering in regular periodic structures are considered traditionally as two entirely opposite phenomena: disorder leads to degradation of coherent Bragg scattering whereas Anderson localization is suppressed by periodicity. Here we reveal a non-trivial link between these two phenomena, through the Fano interference between Bragg scattering and disorder-induced scattering, that triggers both localization and de-localization in random systems. We find unexpected transmission enhancement and spectrum inversion when the Bragg stop-bands are transformed into the Bragg pass-bands solely owing to disorder. Fano resonances are always associated with coherent scattering in regular systems, but our discovery of disorder-induced Fano resonances may provide novel insights into many features of the transport phenomena of photons, phonons, and electrons. Owning to ergodicity, the Fano resonance is a fingerprint feature for any realization of the structure with a certain degree of disorder.

  12. Demonstration of a self-pulsing photonic crystal Fano laser

    DEFF Research Database (Denmark)

    Yu, Yi; Xue, Weiqi; Semenova, Elizaveta

    2017-01-01

    The semiconductor lasers in use today rely on various types of cavity, making use of Fresnel reflection at a cleaved facet', total internal reflection between two different median, Bragg reflection from a periodic stack of layers(3-8), mode coupling in a high contrast grating(9,10) or random...... scattering in a disordered medium". Here, we demonstrate an ultrasmall laser with a mirror, which is based on Fano interference between a continuum of waveguide modes and the discrete resonance of a nanocavity. The rich physics of Fano resonances(12) has recently been explored in a number of different...... photonic and plasmonic systems(13,14). The Fano resonance leads to unique laser characteristics. In particular, because the Fano mirror is very narrowband compared to conventional laser mirrors, the laser is single mode and can be modulated via the mirror. We show, experimentally and theoretically...

  13. Resonant Meta-atoms with Nonlinearities on Demand

    CERN Document Server

    Filonov, Dmitry; Kozlov, Vitali; Malomed, Boris A; Ginzburg, Pavel

    2016-01-01

    Nonlinear light-matter interactions and their applications are constrained by properties of available materials. The use of metamaterials opens the way to achieve precise control over electromagnetic properties at a microscopic level, providing new tools for experimental studies of complex nonlinear phenomena in photonics. Here a doubly resonant nonlinear meta-atom is proposed, analyzed and characterized in the GHz spectral range. The underlying structure is composed of a pair of split rings, resonant at both fundamental and nonlinear frequencies. The rings share a varactor diode, which serves as a microscopic source of nonlinearity. Flexible control over the coupling and near- and far-field patterns are reported, favoring the doubly resonant structure over other realizations. Relative efficiencies of the second and third harmonics, generated by the diode, are tailored by dint of the double-ring geometry, providing a guideline for selecting one frequency against another, using the design of the auxiliary stru...

  14. Nonlinear plasmonic amplification via dissipative soliton-plasmon resonances

    Science.gov (United States)

    Ferrando, Albert

    2017-01-01

    In this contribution we introduce a strategy for the compensation of plasmonic losses based on a recently proposed nonlinear mechanism: the resonant interaction between surface plasmon polaritons and spatial solitons propagating in parallel along a metal/dielectric/Kerr structure. This mechanism naturally leads to the generation of a quasiparticle excitation, the so-called soliplasmon resonance. We analyze the role played by the effective nonlinear coupling inherent to this system and how this can be used to provide a mechanism of quasiresonant nonlinear excitation of surface plasmon polaritons. We will pay particular attention to the introduction of asymmetric linear gain in the Kerr medium. The unique combination of nonlinear propagation, nonlinear coupling, and gain give rise to a scenario for the excitation of long-range surface plasmon polaritons with distinguishing characteristics. The connection between plasmonic losses and soliplasmon resonances in the presence of gain will be discussed.

  15. Multiple Fano interferences in a plasmonic metamolecule consisting of asymmetric metallic nanodimers

    Energy Technology Data Exchange (ETDEWEB)

    Le, Khai Q., E-mail: khai.lequang@hoasen.edu.vn [Faculty of Science and Technology, Hoa Sen University, Ho Chi Minh (Viet Nam); Department of Electrical Engineering, University of Minnesota, Duluth, Minnesota 55812 (United States); Alù, Andrea [Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 77812 (United States); Bai, Jing [Department of Electrical Engineering, University of Minnesota, Duluth, Minnesota 55812 (United States)

    2015-01-14

    We theoretically explore signatures of plasmonic Fano interferences in a subwavelength plasmonic metamolecule consisting of closely packed asymmetric gold nanodimers, which lead to the possibility of generating multiple Fano resonances in the scattering spectrum. This spectral feature is attributed to the interference between bright and dark plasmonic modes sustained by the constituent nanodimers. The excited Fano dips are highly sensitive in both wavelength and amplitude to geometry and background dielectric medium. The tunability of induced Fano resonances associated with enhanced electric fields from the visible to infrared region provides promising applications, particularly in refractive index sensing, light-trapping, and photon up-converting.

  16. Giant In-Particle Field Concentration and Fano Resonances at Light Scattering by High-Refractive Index Particles

    CERN Document Server

    Tribelsky, M I

    2015-01-01

    A detailed analytical inspection of light scattering by a particle with high refractive index m+i\\kappa and small dissipative constant \\kappa is presented. We have shown that there is a dramatic difference in the behavior of the electromagnetic field within the particle (inner problem) and the scattered field outside it (outer problem). With an increase in m at fix values of the other parameters, the field within the particle asymptotically converges to a periodic function of m. The electric and magnetic type Mie resonances of different orders overlap substantially. It may lead to a giant concentration of the electromagnetic energy within the particle. At the same time, we demonstrate that identical transformations of the solution for the outer problem allow to present each partial scattered wave as a sum of two partitions. One of them corresponds to the m-independent wave, scattered by a perfectly reflecting particle and plays the role of a background, while the other is associated with the excitation of a s...

  17. Free-vibration acoustic resonance of a nonlinear elastic bar

    Science.gov (United States)

    Tarumi, Ryuichi; Oshita, Yoshihito

    2011-02-01

    Free-vibration acoustic resonance of a one-dimensional nonlinear elastic bar was investigated by direct analysis in the calculus of variations. The Lagrangian density of the bar includes a cubic term of the deformation gradient, which is responsible for both geometric and constitutive nonlinearities. By expanding the deformation function into a complex Fourier series, we derived the action integral in an analytic form and evaluated its stationary conditions numerically with the Ritz method for the first three resonant vibration modes. This revealed that the bar shows the following prominent nonlinear features: (i) amplitude dependence of the resonance frequency; (ii) symmetry breaking in the vibration pattern; and (iii) excitation of the high-frequency mode around nodal-like points. Stability of the resonant vibrations was also addressed in terms of a convex condition on the strain energy density.

  18. Analysis of nonlinear transient responses of piezoelectric resonators.

    Science.gov (United States)

    Hagiwara, Manabu; Takahashi, Seita; Hoshina, Takuya; Takeda, Hiroaki; Tsurumi, Takaaki

    2011-09-01

    The electric transient response method is an effective technique to evaluate material constants of piezoelectric ceramics under high-power driving. In this study, we tried to incorporate nonlinear piezoelectric behaviors in the analysis of transient responses. As a base for handling the nonlinear piezoelectric responses, we proposed an assumption that the electric displacement is proportional to the strain without phase lag, which could be described by a real and constant piezoelectric e-coefficient. Piezoelectric constitutive equations including nonlinear responses were proposed to calculate transient responses of a piezoelectric resonator. The envelopes and waveforms of current and vibration velocity in transient responses observed in some piezoelectric ceramics could be fitted with the calculation including nonlinear responses. The procedure for calculation of mechanical quality factor Q(m) for piezoelectric resonators with nonlinear behaviors was also proposed.

  19. Nonlinear Resonance Islands and Modulational Effects in a Proton Synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Satogata, Todd Jeffrey [Northwestern Univ., Evanston, IL (United States)

    1993-01-01

    We examine both one-dimensional and two-dimensional nonlinear resonance islands created in the transverse phase space of a proton synchrotron by nonlinear magnets. We also examine application of the theoretical framework constructed to the phenomenon of modulational diffusion in a collider model of the Fermilab Tevatron. For the one-dimensional resonance island system, we examine the effects of two types of modulational perturbations on the stability of these resonance islands: tune modulation and beta function modulation. Hamiltonian models are presented which predict stability boundaries that depend on only three paramders: the strength and frequency of the modulation and the frequency of small oscillations inside the resonance island. These. models are compared to particle tracking with excellent agreement. The tune modulation model is also successfully tested in experiment, where frequency domain analysis coupled with tune modulation is demonstrated to be useful in measuring the strength of a nonlinear resonance. Nonlinear resonance islands are also examined in two transverse dimensions in the presence of coupling and linearly independent crossing resonances. We present a first-order Hamiltonian model which predicts fixed point locations, but does not reproduce small oscillation frequencies seen in tracking; therefore in this circumstance such a model is inadequate. Particle tracking is presented which shows evidence of two-dimensional persistent signals, and we make suggestions on methods for observing such signals in future experiment.

  20. Nonlinear mechanical resonators for ultra-sensitive mass detection

    Energy Technology Data Exchange (ETDEWEB)

    Datskos, Panos G [ORNL; Lavrik, Nickolay V [ORNL

    2014-01-01

    The fundamental sensitivity limit of an appropriately scaled down mechanical resonator can approach one atomic mass unit when only thermal noise is present in the system. However, operation of such nanoscale mechanical resonators is very challenging due to minuteness of their oscillation amplitudes and presence of multiple noise sources in real experimental environments. In order to surmount these challenges, we use microscale cantilever resonators driven to large amplitudes, far beyond their nonlinear instability onset. Our experiments show that such a nonlinear cantilever resonator, described analytically as a Duffing oscillator, has mass sensing performance comparable to that of much smaller resonators operating in a linear regime. We demonstrate femtogram level mass sensing that relies on a bifurcation point tracking that does not require any complex readout means. Our approaches enable straightforward detection of mass changes that are near the fundamental limit imposed by thermo-mechanical fluctuations.

  1. Observation of nonlinear resonances in the advanced light source

    Science.gov (United States)

    Robin, D.; Collins, H.; Decking, W.; Portmann, G.; Schachinger, L.; Zholents, A.

    1995-09-01

    Observations of nonlinear resonances in the Advanced Light Source have been made by scanning betatron tunes and observing count rates in a beam-loss radiation monitor placed down stream of a beam scraper. We have found that it is possible to see structural resonances which are unallowed as well as those which are allowed by the ring's natural 12-fold symmetry. By systematically breaking the amount of symmetry we see that the widths of the unallowed resonances grow while the widths of the allowed resonances do not. In this paper we briefly discuss the importance of symmetry and its effect on resonances in the design of the ALS. Next we describe our experimental setup and discuss the performance of the beam loss monitor which we used to view the resonances. We then present scans of the tune space where one can see the presence of the structural resonances and their evolution when the lattice symmetry is systematically broken.

  2. Nonlinear and quantum optics with whispering gallery resonators

    Science.gov (United States)

    Strekalov, Dmitry V.; Marquardt, Christoph; Matsko, Andrey B.; Schwefel, Harald G. L.; Leuchs, Gerd

    2016-12-01

    Optical whispering gallery modes (WGMs) derive their name from a famous acoustic phenomenon of guiding a wave by a curved boundary observed nearly a century ago. This phenomenon has a rather general nature, equally applicable to sound and all other waves. It enables resonators of unique properties attractive both in science and engineering. Very high quality factors of optical WGM resonators persisting in a wide wavelength range spanning from radio frequencies to ultraviolet light, their small mode volume, and tunable in- and out- coupling make them exceptionally efficient for nonlinear optical applications. Nonlinear optics facilitates interaction of photons with each other and with other physical systems, and is of prime importance in quantum optics. In this paper we review numerous applications of WGM resonators in nonlinear and quantum optics. We outline the current areas of interest, summarize progress, highlight difficulties, and discuss possible future development trends in these areas.

  3. Magneto-induced Fano-like cavity interference in three-dimensional metamaterials

    Science.gov (United States)

    Pan, Xun-Yong; Wang, Gaofeng

    2016-08-01

    Fano-like cavity interference due to magneto-inductive coupling in metamaterial structure is demonstrated via a double Fabry-Perot cavity (DFPC) that consists of stacked multi-layered resonators. The induced magnetic field based destructive interference is observed in the transmission response of the DFPC system, which exhibits the Fano line shaped resonance. The retrieved real and imaginary parts of effective permeability and permittivity indicate strong magneto-induced dispersion with a group delay leading to the slow light effect. This finding provides an interesting mechanism to excite Fano resonances in metamaterial systems via magnetic interaction between resonators, which may enable new devices for slow light and sensing applications.

  4. Classification of smooth Fano polytopes

    DEFF Research Database (Denmark)

    Øbro, Mikkel

    Fano polytopes up to isomorphism. A smooth Fano -polytope can have at most vertices. In case of vertices an explicit classification is known. The thesis contains the classification in case of vertices. Classifications of smooth Fano -polytopes for fixed exist only for . In the thesis an algorithm...... for the classification of smooth Fano -polytopes for any given is presented. The algorithm has been implemented and used to obtain the complete classification for .......A simplicial lattice polytope containing the origin in the interior is called a smooth Fano polytope, if the vertices of every facet is a basis of the lattice. The study of smooth Fano polytopes is motivated by their connection to toric varieties. The thesis concerns the classification of smooth...

  5. Resonance phenomena for asymmetric weakly nonlinear oscillator

    Institute of Scientific and Technical Information of China (English)

    钱定边

    2002-01-01

    We establish the coexistence of periodic solution and unbounded solution, the infinity of largeamplitude subharmonics for asymmetric weakly nonlinear oscillator x" + a2x+ - b2x- + h(x) = p(t) with h(±∞) - 0 and xh(x) → +∞(x →∞), assuming that M(τ ) has zeros which are all simple and M(τ ) 0respectively, where M(τ ) is a function related to the piecewise linear equation x" + a2x+ - b2x- = p(t).``

  6. Nonlinear Response of Cantilever Beams to Combination and Subcombination Resonances

    Directory of Open Access Journals (Sweden)

    Ali H. Nayfeh

    1998-01-01

    Full Text Available The nonlinear planar response of cantilever metallic beams to combination parametric and external subcombination resonances is investigated, taking into account the effects of cubic geometric and inertia nonlinearities. The beams considered here are assumed to have large length-to-width aspect ratios and thin rectangular cross sections. Hence, the effects of shear deformations and rotatory inertia are neglected. For the case of combination parametric resonance, a two-mode Galerkin discretization along with Hamilton’s extended principle is used to obtain two second-order nonlinear ordinary-differential equations of motion and associated boundary conditions. Then, the method of multiple scales is applied to obtain a set of four first-order nonlinear ordinary-differential equations governing the modulation of the amplitudes and phases of the two excited modes. For the case of subcombination resonance, the method of multiple scales is applied directly to the Lagrangian and virtual-work term. Then using Hamilton’s extended principle, we obtain a set of four first-order nonlinear ordinary-differential equations governing the amplitudes and phases of the two excited modes. In both cases, the modulation equations are used to generate frequency- and force-response curves. We found that the trivial solution exhibits a jump as it undergoes a subcritical pitchfork bifurcation. Similarly, the nontrivial solutions also exhibit jumps as they undergo saddle-node bifurcations.

  7. Nonlinear resonances of a single-wall carbon nanotube cantilever

    Science.gov (United States)

    Kim, I. K.; Lee, S. I.

    2015-03-01

    The dynamics of an electrostatically actuated carbon nanotube (CNT) cantilever are discussed by theoretical and numerical approaches. Electrostatic and intermolecular forces between the single-walled CNT and a graphene electrode are considered. The CNT cantilever is analyzed by the Euler-Bernoulli beam theory, including its geometric and inertial nonlinearities, and a one-mode projection based on the Galerkin approximation and numerical integration. Static pull-in and pull-out behaviors are adequately represented by an asymmetric two-well potential with the total potential energy consisting of the CNT elastic energy, electrostatic energy, and the Lennard-Jones potential energy. Nonlinear dynamics of the cantilever are simulated under DC and AC voltage excitations and examined in the frequency and time domains. Under AC-only excitation, a superharmonic resonance of order 2 occurs near half of the primary frequency. Under both DC and AC loads, the cantilever exhibits linear and nonlinear primary and secondary resonances depending on the strength of the excitation voltages. In addition, the cantilever has dynamic instabilities such as periodic or chaotic tapping motions, with a variation of excitation frequency at the resonance branches. High electrostatic excitation leads to complex nonlinear responses such as softening, multiple stability changes at saddle nodes, or period-doubling bifurcation points in the primary and secondary resonance branches.

  8. Nonlinear and Quantum Optics with Whispering Gallery Resonators

    CERN Document Server

    Strekalov, Dmitry V; Matsko, Andrey B; Schwefel, Harald G L; Leuchs, Gerd

    2016-01-01

    Optical Whispering Gallery Modes (WGMs) derive their name from a famous acoustic phenomenon of guiding a wave by a curved boundary observed nearly a century ago. This phenomenon was later realized to have a rather general nature, equally applicable to sound and all other waves, but in particular also to electromagnetic waves ranging from radio frequencies to ultraviolet light. Very high quality factors of optical WGM resonators persisting in a wide wavelength range, their small mode volume, and tunable in- and out- coupling make them exceptionally efficient for nonlinear optical applications. Nonlinear optics facilitates interaction of photons with each other and with other physical systems, and is of prime importance in quantum optics. In this paper we review numerous applications of WGM resonators in nonlinear and quantum optics. We outline the current areas of interest, summarize progress, highlight difficulties, and discuss possible future development trends in these areas.

  9. Sensitivity of nonlinear photoionization to resonance substructure in collective excitation

    Science.gov (United States)

    Mazza, T.; Karamatskou, A.; Ilchen, M.; Bakhtiarzadeh, S.; Rafipoor, A. J.; O'Keeffe, P.; Kelly, T. J.; Walsh, N.; Costello, J. T.; Meyer, M.; Santra, R.

    2015-04-01

    Collective behaviour is a characteristic feature in many-body systems, important for developments in fields such as magnetism, superconductivity, photonics and electronics. Recently, there has been increasing interest in the optically nonlinear response of collective excitations. Here we demonstrate how the nonlinear interaction of a many-body system with intense XUV radiation can be used as an effective probe for characterizing otherwise unresolved features of its collective response. Resonant photoionization of atomic xenon was chosen as a case study. The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance. Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources.

  10. Exploiting nonlinearities of micro-machined resonators for filtering applications

    KAUST Repository

    Ilyas, Saad

    2017-06-21

    We demonstrate the exploitation of the nonlinear behavior of two electrically coupled microbeam resonators to realize a band-pass filter. More specifically, we combine their nonlinear hardening and softening responses to realize a near flat pass band filter with sharp roll-off characteristics. The device is composed of two near identical doubly clamped and electrostatically actuated microbeams made of silicon. One of the resonators is buckled via thermal loading to produce a softening frequency response. It is then further tuned to create the desired overlap with the second resonator response of hardening behavior. This overlapping improves the pass band flatness. Also, the sudden jumps due to the softening and hardening behaviors create sharp roll-off characteristics. This approach can be promising for the future generation of filters with superior characteristics.

  11. On the nonlinear resonances and dynamic pull-in of electrostatically actuated resonators

    Science.gov (United States)

    Alsaleem, Fadi M.; Younis, Mohammad I.; Ouakad, Hassen M.

    2009-04-01

    We present modeling, analysis and experimental investigation for nonlinear resonances and the dynamic pull-in instability in electrostatically actuated resonators. These phenomena are induced by exciting a microstructure with nonlinear forcing composed of a dc parallel-plate electrostatic load superimposed on an ac harmonic load. Nonlinear phenomena are investigated experimentally and theoretically including primary resonance, superharmonic and subharmonic resonances, dynamic pull-in and the escape-from-potential-well phenomenon. As a case study, a capacitive sensor made up of two cantilever beams with a proof mass attached to their tips is studied. A nonlinear spring-mass-damper model is utilized accounting for squeeze-film damping and the parallel-plate electrostatic force. Long-time integration and a global dynamic analysis are conducted using a finite-difference method combined with the Floquet theory to capture periodic orbits and analyze their stability. The domains of attraction (basins of attraction) for data points on the frequency-response curve are calculated numerically. Dover cliff integrity curves are calculated and the erosion of the safe basin of attraction is investigated as the frequency of excitation is swept passing primary resonance and dynamic pull-in. Conclusions are presented regarding the safety and integrity of MEMS resonators based on the simulated basin of attraction and the observed experimental data.

  12. Modeling of the nonlinear resonant response in sedimentary rocks

    Energy Technology Data Exchange (ETDEWEB)

    Ten Cate, James A [Los Alamos National Laboratory; Shankland, Thomas J [Los Alamos National Laboratory; Vakhnenko, Vyacheslav O [NON LANL; Vakhnenko, Oleksiy [NON LANL

    2009-04-03

    We suggest a model for describing a wide class of nonlinear and hysteretic effects in sedimentary rocks at longitudinal bar resonance. In particular, we explain: hysteretic behaviour of a resonance curve on both its upward and downward slopes; linear softening of resonant frequency with increase of driving level; gradual (almost logarithmic) recovery of resonant frequency after large dynamical strains; and temporal relaxation of response amplitude at fixed frequency. Starting with a suggested model, we predict the dynamical realization of end-point memory in resonating bar experiments with a cyclic frequency protocol. These theoretical findings were confirmed experimentally at Los Alamos National Laboratory. Sedimentary rocks, particularly sandstones, are distinguished by their grain structure in which each grain is much harder than the intergrain cementation material. The peculiarities of grain and pore structures give rise to a variety of remarkable nonlinear mechanical properties demonstrated by rocks, both at quasistatic and alternating dynamic loading. Thus, the hysteresis earlier established for the stress-strain relation in samples subjected to quasistatic loading-unloading cycles has also been discovered for the relation between acceleration amplitude and driving frequency in bar-shaped samples subjected to an alternating external drive that is frequency-swept through resonance. At strong drive levels there is an unusual, almost linear decrease of resonant frequency with strain amplitude, and there are long-term relaxation phenomena such as nearly logarithmic recovery (increase) of resonant frequency after the large conditioning drive has been removed. In this report we present a short sketch of a model for explaining numerous experimental observations seen in forced longitudinal oscillations of sandstone bars. According to our theory a broad set of experimental data can be understood as various aspects of the same internally consistent pattern. Furthermore

  13. Dissimilar trend of nonlinearity in ultrasound transducers and systems at resonance and non-resonance frequencies

    DEFF Research Database (Denmark)

    Ghasemi, Negareh; Zare, Firuz; Davari, Pooya

    2017-01-01

    Several factors can affect performance of an ultrasound system such as quality of excitation signal and ultrasound transducer behaviour. Nonlinearity of piezoelectric ultrasound transducers is a key determinant in designing a proper driving power supply. Although, the nonlinearity of piezoelectri...... receiver is a function of a voltage across the resistor in the RLC branches and is related to the resonance frequencies of the ultrasound transducer....

  14. Nonlinear dynamics of giant resonances in atomic nuclei

    CERN Document Server

    Vretenar, D; Ring, P; Lalazissis, G A

    1999-01-01

    The dynamics of monopole giant resonances in nuclei is analyzed in the time-dependent relativistic mean-field model. The phase spaces of isoscalar and isovector collective oscillations are reconstructed from the time-series of dynamical variables that characterize the proton and neutron density distributions. The analysis of the resulting recurrence plots and correlation dimensions indicate regular motion for the isoscalar mode, and chaotic dynamics for the isovector oscillations. Information-theoretic functionals identify and quantify the nonlinear dynamics of giant resonances in quantum systems that have spatial as well as temporal structure.

  15. Internal Resonance in a Vibrating Beam: A Zoo of Nonlinear Resonance Peaks.

    Science.gov (United States)

    Mangussi, Franco; Zanette, Damián H

    2016-01-01

    In oscillating mechanical systems, nonlinearity is responsible for the departure from proportionality between the forces that sustain their motion and the resulting vibration amplitude. Such effect may have both beneficial and harmful effects in a broad class of technological applications, ranging from microelectromechanical devices to edifice structures. The dependence of the oscillation frequency on the amplitude, in particular, jeopardizes the use of nonlinear oscillators in the design of time-keeping electronic components. Nonlinearity, however, can itself counteract this adverse response by triggering a resonant interaction between different oscillation modes, which transfers the excess of energy in the main oscillation to higher harmonics, and thus stabilizes its frequency. In this paper, we examine a model for internal resonance in a vibrating elastic beam clamped at its two ends. In this case, nonlinearity occurs in the form of a restoring force proportional to the cube of the oscillation amplitude, which induces resonance between modes whose frequencies are in a ratio close to 1:3. The model is based on a representation of the resonant modes as two Duffing oscillators, coupled through cubic interactions. Our focus is put on illustrating the diversity of behavior that internal resonance brings about in the dynamical response of the system, depending on the detailed form of the coupling forces. The mathematical treatment of the model is developed at several approximation levels. A qualitative comparison of our results with previous experiments and numerical calculations on elastic beams is outlined.

  16. Internal Resonance in a Vibrating Beam: A Zoo of Nonlinear Resonance Peaks

    Science.gov (United States)

    Mangussi, Franco

    2016-01-01

    In oscillating mechanical systems, nonlinearity is responsible for the departure from proportionality between the forces that sustain their motion and the resulting vibration amplitude. Such effect may have both beneficial and harmful effects in a broad class of technological applications, ranging from microelectromechanical devices to edifice structures. The dependence of the oscillation frequency on the amplitude, in particular, jeopardizes the use of nonlinear oscillators in the design of time-keeping electronic components. Nonlinearity, however, can itself counteract this adverse response by triggering a resonant interaction between different oscillation modes, which transfers the excess of energy in the main oscillation to higher harmonics, and thus stabilizes its frequency. In this paper, we examine a model for internal resonance in a vibrating elastic beam clamped at its two ends. In this case, nonlinearity occurs in the form of a restoring force proportional to the cube of the oscillation amplitude, which induces resonance between modes whose frequencies are in a ratio close to 1:3. The model is based on a representation of the resonant modes as two Duffing oscillators, coupled through cubic interactions. Our focus is put on illustrating the diversity of behavior that internal resonance brings about in the dynamical response of the system, depending on the detailed form of the coupling forces. The mathematical treatment of the model is developed at several approximation levels. A qualitative comparison of our results with previous experiments and numerical calculations on elastic beams is outlined. PMID:27648829

  17. Multistable internal resonance in electroelastic crystals with nonlinearly coupled modes

    Science.gov (United States)

    Kirkendall, Christopher R.; Kwon, Jae W.

    2016-03-01

    Nonlinear modal interactions have recently become the focus of intense research in micro- and nanoscale resonators for their use to improve oscillator performance and probe the frontiers of fundamental physics. However, our understanding of modal coupling is largely restricted to clamped-clamped beams, and lacking in systems with both geometric and material nonlinearities. Here we report multistable energy transfer between internally resonant modes of an electroelastic crystal plate and use a mixed analytical-numerical approach to provide new insight into these complex interactions. Our results reveal a rich bifurcation structure marked by nested regions of multistability. Even the simple case of two coupled modes generates a host of topologically distinct dynamics over the parameter space, ranging from the usual Duffing bistability to complex multistable behaviour and quasiperiodic motion.

  18. Frequency-tunable superconducting resonators via nonlinear kinetic inductance

    Energy Technology Data Exchange (ETDEWEB)

    Vissers, M. R.; Hubmayr, J.; Sandberg, M.; Gao, J. [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Chaudhuri, S. [Department of Physics, Stanford University, Stanford, California 94305 (United States); Bockstiegel, C. [Department of Physics, University of California, Santa Barbara, California 93106 (United States)

    2015-08-10

    We have designed, fabricated, and tested a frequency-tunable high-Q superconducting resonator made from a niobium titanium nitride film. The frequency tunability is achieved by injecting a DC through a current-directing circuit into the nonlinear inductor whose kinetic inductance is current-dependent. We have demonstrated continuous tuning of the resonance frequency in a 180 MHz frequency range around 4.5 GHz while maintaining the high internal quality factor Q{sub i} > 180 000. This device may serve as a tunable filter and find applications in superconducting quantum computing and measurement. It also provides a useful tool to study the nonlinear response of a superconductor. In addition, it may be developed into techniques for measurement of the complex impedance of a superconductor at its transition temperature and for readout of transition-edge sensors.

  19. Double resonant processes in $\\chi^{(2)}$ nonlinear periodic media

    OpenAIRE

    Konotop, V. V.; Kuzmiak, V.

    2000-01-01

    In a one-dimensional periodic nonlinear $\\chi^{(2)}$ medium, by choosing a proper material and geometrical parameters of the structure, it is possible to obtain two matching conditions for simultaneous generation of second and third harmonics. This leads to new diversity of the processes of the resonant three-wave interactions, which are discussed within the framework of slowly varying envelope approach. In particular, we concentrate on the fractional conversion of the frequency $\\omega \\to (...

  20. Analysis and design of nonlinear resonances via singularity theory

    CERN Document Server

    Cirillo, G I; Kerschen, G; Sepulchre, R

    2016-01-01

    Bifurcation theory and continuation methods are well-established tools for the analysis of nonlinear mechanical systems subject to periodic forcing. We illustrate the added value and the complementary information provided by singularity theory with one distinguished parameter. While tracking bifurcations reveals the qualitative changes in the behaviour, tracking singularities reveals how structural changes are themselves organised in parameter space. The complementarity of that information is demonstrated in the analysis of detached resonance curves in a two-degree-of-freedom system.

  1. Analysis and design of nonlinear resonances via singularity theory

    Science.gov (United States)

    Cirillo, G. I.; Habib, G.; Kerschen, G.; Sepulchre, R.

    2017-03-01

    Bifurcation theory and continuation methods are well-established tools for the analysis of nonlinear mechanical systems subject to periodic forcing. We illustrate the added value and the complementary information provided by singularity theory with one distinguished parameter. While tracking bifurcations reveals the qualitative changes in the behaviour, tracking singularities reveals how structural changes are themselves organised in parameter space. The complementarity of that information is demonstrated in the analysis of detached resonance curves in a two-degree-of-freedom system.

  2. Kinetic equation for nonlinear resonant wave-particle interaction

    Science.gov (United States)

    Artemyev, A. V.; Neishtadt, A. I.; Vasiliev, A. A.; Mourenas, D.

    2016-09-01

    We investigate the nonlinear resonant wave-particle interactions including the effects of particle (phase) trapping, detrapping, and scattering by high-amplitude coherent waves. After deriving the relationship between probability of trapping and velocity of particle drift induced by nonlinear scattering (phase bunching), we substitute this relation and other characteristic equations of wave-particle interaction into a kinetic equation for the particle distribution function. The final equation has the form of a Fokker-Planck equation with peculiar advection and collision terms. This equation fully describes the evolution of particle momentum distribution due to particle diffusion, nonlinear drift, and fast transport in phase-space via trapping. Solutions of the obtained kinetic equation are compared with results of test particle simulations.

  3. Nonreciprocal transmission in a photonic-crystal Fano structure enabled by symmetry breaking

    CERN Document Server

    Yu, Yi; Hu, Hao; Xue, Weiqi; Yvind, Kresten; Mørk, Jesper

    2014-01-01

    Nanostructures that feature nonreciprocal light transmission are highly desirable building blocks for realizing photonic integrated circuits. Here, a simple and ultra-compact photonic-crystal structure, where a waveguide is coupled to a single nanocavity, is proposed and experimentally demonstrated, showing very efficient optical diode functionality. The key novelty of the structure is the use of a Fano resonance in combination with spatial symmetry breaking and cavity enhanced material nonlinearities to realize non-reciprocal propagation effects at ultra-low power and with a good wavelength tunability. The nonlinearity of the device relies on ultrafast carrier dynamics, rather than the thermal effects usually considered, allowing the demonstration of nonreciprocal operation at a bit-rate of 10 Gbit/s with a low energy consumption of 4.5 fJ/bit.

  4. Resonances in nonlinear structure vibrations under multifrequency excitations

    Energy Technology Data Exchange (ETDEWEB)

    El-Bassiouny, A F [Faculty of Science, Mathematics Department, Benha University, Benha 1358 (Egypt); El-Latif, G M Abd [Faculty of Science, Mathematics Department, Sohag University, Sohag (Egypt)

    2006-10-15

    The response of a single-degree-of-freedom system with quadratic, cubic and quartic nonlinearities subjected to a sinusoidal excitation that involves multiple frequencies is considered. The method of multiple scales is used to construct a first order uniform expansion yielding two first-order nonlinear ordinary differential equations that are derived for the evolution of the amplitude and phase. These oscillations involve a subharmonic oscillation of order one-fourth and superharmonic oscillation of order two. Steady state responses and their stability are computed for selected values of the system parameters. The effects of these (quadratic, cubic, and quartic) nonlinearities on these oscillations are specifically investigated. With this study, it has been verified that the qualitative effects of these nonlinearities are different. Regions of hardening (softening) behaviour of the system exist for the case of subharmonic resonance. The response curve is not affected by decreasing the damping factor for the case of superharmonic resonance. It is shown that the response curve contracts or expands as the parameters vary. The multivalued region increases or decreases when some parameters vary.

  5. Nonlinear dynamic response of an electrically actuated imperfect microbeam resonator

    KAUST Repository

    Ruzziconi, Laura

    2013-08-04

    We present a study of the dynamic behavior of a MEMS device constituted of an imperfect clamped-clamped microbeam subjected to electrostatic and electrodynamic actuation. Our objective is to develop a theoretical analysis, which is able to describe and predict all the main relevant aspects of the experimental response. Extensive experimental investigation is conducted, where the main imperfections coming from microfabrication are detected and the nonlinear dynamics are explored at increasing values of electrodynamic excitation, in a neighborhood of the first symmetric resonance. The nonlinear behavior is highlighted, which includes ranges of multistability, where the non-resonant and the resonant branch coexist, and intervals where superharmonic resonances are clearly visible. Numerical simulations are performed. Initially, two single mode reduced-order models are considered. One is generated via the Galerkin technique, and the other one via the combined use of the Ritz method and the Padé approximation. Both of them are able to provide a satisfactory agreement with the experimental data. This occurs not only at low values of electrodynamic excitation, but also at higher ones. Their computational efficiency is discussed in detail, since this is an essential aspect for systematic local and global simulations. Finally, the theoretical analysis is further improved and a two-degree-of-freedom reduced-order model is developed, which is capable also to capture the measured second symmetric superharmonic resonance. Despite the apparent simplicity, it is shown that all the proposed reduced-order models are able to describe the experimental complex nonlinear dynamics of the device accurately and properly, which validates the proposed theoretical approach. Copyright © 2013 by ASME.

  6. Linear and nonlinear optics of hybrid plasmon-exciton nanomaterials in the presence of overlapping resonances

    CERN Document Server

    Sukharev, Maxim; Pachter, Ruth

    2015-01-01

    We consider a hybrid plasmon-exciton system comprised of a resonant molecular subsystem and three Au wires supporting a dipole mode which can be coupled to a dark mode in controllable fashion by variation of a symmetry parameter. The physics of such a system under strong coupling conditions is examined in detail. It is shown that if two wires supporting the dark mode are covered with molecular layers the system exhibits four resonant modes for a strong coupling regime due to asymmetry and lifted degeneracy of the molecular state in this case, while upon having molecular aggregates covering the top wire with dipolar mode, three resonant modes appear. Pump-probe simulations are performed to scrutinize the quantum dynamics and find possible ways to control plasmon-exciton materials. It is demonstrated that one can design hybrid nanomaterials with highly pronounced Fano-type resonances when excited by femtosecond lasers.

  7. Nonlinear Resonance Benchmarking Experiment at the CERN Proton Synchrotron

    CERN Document Server

    Hofmann, I; Giovannozzi, Massimo; Martini, M; Métral, Elias

    2003-01-01

    As a first step of a space charge - nonlinear resonance benchmarking experiment over a large number of turns, beam loss and emittance evolution were measured over 1 s on a 1.4 GeV kinetic energy flat-bottom in the presence of a single octupole. By lowering the working point towards the resonance a gradual transition from a loss-free core emittance blow-up to a regime dominated by continuous loss was found. Our 3D simulations with analytical space charge show that trapping on the resonance due to synchrotron oscillation causes the observed core emittance growth as well as halo formation, where the latter is explained as the source of the observed loss.

  8. Quantized amplitudes in a nonlinear resonant electrical circuit

    CERN Document Server

    Cretin, B

    2008-01-01

    We present a simple nonlinear resonant analog circuit which demonstrates quantization of resonating amplitudes, for a given excitation level. The system is a simple RLC resonator where C is an active capacitor whose value is related to the current in the circuit. This variation is energetically equivalent to a variation of the potential energy and the circuit acts as a pendulum in the gravitational field. The excitation voltage, synchronously switched at the current frequency, enables electrical supply and keeping the oscillation of the system. The excitation frequency has been set to high harmonic of the fundamental oscillation so that anisochronicity can keep constant the amplitude of the circuit voltage and current. The behavior of the circuit is unusual: different stable amplitudes have been measured depending on initial conditions and excitation frequency, for the same amplitude of the excitation. The excitation frequency is naturally divided by the circuit and the ratio is kept constant without external...

  9. Mode Coupling and Nonlinear Resonances of MEMS Arch Resonators for Bandpass Filters

    KAUST Repository

    Hajjaj, Amal Z.

    2017-01-30

    We experimentally demonstrate an exploitation of the nonlinear softening, hardening, and veering phenomena (near crossing), where the frequencies of two vibration modes get close to each other, to realize a bandpass filter of sharp roll off from the passband to the stopband. The concept is demonstrated based on an electrothermally tuned and electrostatically driven MEMS arch resonator operated in air. The in-plane resonator is fabricated from a silicon-on-insulator wafer with a deliberate curvature to form an arch shape. A DC current is applied through the resonator to induce heat and modulate its stiffness, and hence its resonance frequencies. We show that the first resonance frequency increases up to twice of the initial value while the third resonance frequency decreases until getting very close to the first resonance frequency. This leads to the phenomenon of veering, where both modes get coupled and exchange energy. We demonstrate that by driving both modes nonlinearly and electrostatically near the veering regime, such that the first and third modes exhibit softening and hardening behavior, respectively, sharp roll off from the passband to the stopband is achievable. We show a flat, wide, and tunable bandwidth and center frequency by controlling the electrothermal actuation voltage.

  10. Photonic Crystal Fano Laser: Terahertz Modulation and Ultrashort Pulse Generation

    DEFF Research Database (Denmark)

    Mørk, Jesper; Chen, Yaohui; Heuck, Mikkel

    2014-01-01

    We suggest and analyze a laser with a mirror realized by Fano interference between a waveguide and a nanocavity. For small-amplitude modulation of the nanocavity resonance, the laser can be modulated at frequencies exceeding 1 THz, not being limited by carrier dynamics as for conventional lasers....

  11. Fano-Induced Circular Dichroism in Three-Dimensional Plasmonic Chiral Metamolecules

    Science.gov (United States)

    Le, Khai Q.

    2017-10-01

    This paper introduces a three-dimensional (3-D) artificial chiral nanostructure, which has variant total optical loss spectroscopies under left- and right-handed circularly polarized (LCP and RCP) incident light. The resulting circular dichroism is induced by Fano resonance generated by the engineered chiral metamolecule, which consists of asymmetrically arranged gold (Au) nanoparticles in three dimensions. The Fano resonance generation is a consequence of modal interference between bright and dark plasmonic modes of asymmetric constituent dimers of the metamolecule.

  12. The inherent complexity in nonlinear business cycle model in resonance

    Energy Technology Data Exchange (ETDEWEB)

    Ma Junhai [School of Management, Tianjin University, Tianjin 300072 (China) and Tianjin University of Finance and Economics, Tianjin 300222 (China)], E-mail: lzqsly@126.com; Sun Tao; Liu Lixia [School of Management, Tianjin University, Tianjin 300072 (China)

    2008-08-15

    Based on Abraham C.-L. Chian's research, we applied nonlinear dynamic system theory to study the first-order and second-order approximate solutions to one category of the nonlinear business cycle model in resonance condition. We have also analyzed the relation between amplitude and phase of second-order approximate solutions as well as the relation between outer excitements' amplitude, frequency approximate solutions, and system bifurcation parameters. Then we studied the system quasi-periodical solutions, annulus periodical solutions and the path leading to system bifurcation and chaotic state with different parameter combinations. Finally, we conducted some numerical simulations for various complicated circumstances. Therefore this research will lay solid foundation for detecting the complexity of business cycles and systems in the future.

  13. Probabilistic approach to nonlinear wave-particle resonant interaction

    Science.gov (United States)

    Artemyev, A. V.; Neishtadt, A. I.; Vasiliev, A. A.; Mourenas, D.

    2017-02-01

    In this paper we provide a theoretical model describing the evolution of the charged-particle distribution function in a system with nonlinear wave-particle interactions. Considering a system with strong electrostatic waves propagating in an inhomogeneous magnetic field, we demonstrate that individual particle motion can be characterized by the probability of trapping into the resonance with the wave and by the efficiency of scattering at resonance. These characteristics, being derived for a particular plasma system, can be used to construct a kinetic equation (or generalized Fokker-Planck equation) modeling the long-term evolution of the particle distribution. In this equation, effects of charged-particle trapping and transport in phase space are simulated with a nonlocal operator. We demonstrate that solutions of the derived kinetic equations agree with results of test-particle tracing. The applicability of the proposed approach for the description of space and laboratory plasma systems is also discussed.

  14. Nonlinear dynamic modeling and resonance tuning of Galfenol vibration absorbers

    Science.gov (United States)

    Scheidler, Justin J.; Dapino, Marcelo J.

    2013-08-01

    This paper investigates the semi-active control of a magnetically-tunable vibration absorber’s resonance frequency. The vibration absorber that is considered is a metal-matrix composite containing the magnetostrictive material Galfenol (FeGa). A single degree of freedom model for the nonlinear vibration of the absorber is presented. The model is valid under arbitrary stress and magnetic field, and incorporates the variation in Galfenol’s elastic modulus throughout the composite as well as Galfenol’s asymmetric tension-compression behavior. Two boundary conditions—cantilevered and clamped-clamped—are imposed on the composite. The frequency response of the absorber to harmonic base excitation is calculated as a function of the operating conditions to determine the composite’s capacity for resonance tuning. The results show that nearly uniform controllability of the vibration absorber’s resonance frequency is possible below a threshold of the input power amplitude using weak magnetic fields of 0-8 kA m-1. Parametric studies are presented to characterize the effect on resonance tunability of Galfenol volume fraction and Galfenol location within the composite. The applicability of the results to composites of varying geometry and containing different Galfenol materials is discussed.

  15. Strong nonlinear harmonic generation in a PZT/Aluminum resonator

    Energy Technology Data Exchange (ETDEWEB)

    Parenthoine, D; Haumesser, L; Meulen, F Vander; Tran-Huu-Hue, L-P, E-mail: parenthoine@univ-tours.f [University Francois Rabelais of Tours, U 930 Imagerie et Cerveau, CNRS 2448, ENIVL, rue de la Chocolaterie, BP 3410, 41034 Blois (France)

    2009-11-01

    In this work, the extentional vibration mode of a coupled PZT/ Aluminum rod resonator is studied experimentally. Geometrical characteristics of the PZT are its 27 mm length and its 4x4 mm{sup 2} cross section area. The excitation voltage consists in sinusoidal bursts in the frequency range (20-80 kHz). Velocity measurements are performed at both ends of this system, using a laser probe. Strong harmonic distortions in the mechanical response (up to -20 dB with respect to the primary wave amplitude) have been observed. The corresponding input levels are far lower than those which are necessary to observe quadratic second harmonic generation in a free PZT resonator. The strong nonlinear effect can be explained as a super-harmonic resonance of the system due to a specific ratio between the eigen frequencies of the two parts of the resonator. Evolution of fundamental and harmonic responses are observed as a function of input levels, highlighting hysteretic behavior.

  16. Unobstructedness of deformations of holomorphic maps onto Fano manifolds of Picard number 1

    CERN Document Server

    Hwang, Jun-Muk

    2009-01-01

    We show that deformations of a surjective morphism onto a Fano manifold of Picard number 1 are unobstructed and rigid modulo the automorphisms of the target, if the variety of minimal rational tangents of the Fano manifold is non-linear or finite. The condition on the variety of minimal rational tangents holds for practically all known examples of Fano manifolds of Picard number 1, except the projective space. When the variety of minimal rational tangents is non-linear, the proof is based on an earlier result of N. Mok and the author on the birationality of the tangent map. When the varieties of minimal rational tangents of the Fano manifold is finite, the key idea is to factorize the given surjective morphism, after some transformation, through a universal morphism associated to the minimal rational curves.

  17. Acoustic transparency and opacity using Fano Interferences in Metamaterials

    KAUST Repository

    Khelif, A.

    2015-08-04

    We investigate both experimentally and theoretically how to generate the acoustical analogue of the Electromagnetically Induced Transparency. This phenomenon arises from Fano resonances originating from constructive and destructive interferences of a narrow discrete resonance with a broad spectral line or continuum. Measurements were realized on a double-cavity structure by using a Kundt’s Tube. Transmission properties reveal an asymmetric lineshape of the transmission that leads to acoustic transparency.

  18. NERO a code for evaluation of nonlinear resonances in 4D symplectic mappings

    CERN Document Server

    Todesco, Ezio; Giovannozzi, Massimo

    1998-01-01

    A code to evaluate the stability, the position and the width of nonlinear resonances in four-dimensional symplectic mappings is described. NERO is based on the computation of the resonant perturbative series through the use of Lie transformation implemented in the code ARES, and on the analysis of the resonant orbits of the interpolating Hamiltonian. The code is aimed at studying the nonlinear moti on of a charged particle moving in a circular accelerator under the influence of nonlinear forces.

  19. Asymmetric split nanorings for Fano induced plasmonic sensor in visible region

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yao, E-mail: dingyao@cqcet.com [General Education College, Chongqing College of Electronic Engineering, Chongqing 401331 (China); Liao, Zhongwei, E-mail: liaozw@cqu.edu.cn [Soft Matter and Interdisciplinary Research Institute, College of Physics, Chongqing University, Chongqing 401331 (China)

    2015-05-01

    Fano resonance exhibits high sensitivity and promising applications in the field of ultra-sensitive plasmonic sensor. In this work, the Fano lineshape in spectra of gold rectangular split nanorings (RSNRs) is investigated using the finite element method. The simulation results figure out the Fano lineshape could be modulated by the positions of split gap in RSNRs for symmetry breaking, which is explained by the plasmonic hybridization theory. Furthermore, the high order bonding plasmon mode H in absorption spectra exhibits high sensitivity in visible region. Our investigations here are beneficial for the design and application of ultra-sensitive LSPR sensor in visible region.

  20. Higher order Fano graphene metamaterials for nanoscale optical sensing.

    Science.gov (United States)

    Guo, Xiangdong; Hu, Hai; Zhu, Xing; Yang, Xiaoxia; Dai, Qing

    2017-09-28

    Plasmonic Fano metamaterials provide a unique platform for optical sensing applications due to their sharp spectral response and the ability to confine light to nanoscale regions that make them a strong prospect for refractive-index sensing. Higher order Fano resonance modes in noble metal plasmonic structures can further improve the sensitivity, but their applications are heavily limited by crosstalk between different modes due to the large damping rates and broadband spectral responses of the metal plasmon modes. Here, we create pure higher order Fano modes by designing asymmetric metamaterials comprised of a split-ring resonator and disk with a low-loss graphene plasmon. These higher order modes are highly sensitive to the nanoscale analyte (8 nm thick) both in refractive-index and in infrared vibrational fingerprint sensing, as demonstrated by the numerical calculation. The frequency sensitivity and figure-of-merit of the hexacontatetrapolar mode can reach 289 cm(-1) per RIU and 29, respectively, and it can probe the weak infrared vibrational modes of the analyte with more than 400 times enhancement. The enhanced sensitivity and tunability of higher order Fano graphene metamaterials promise a high-performance nanoscale optical sensor.

  1. Surpassing Fundamental Limits of Oscillators Using Nonlinear Resonators

    Science.gov (United States)

    Villanueva, L. G.; Kenig, E.; Karabalin, R. B.; Matheny, M. H.; Lifshitz, Ron; Cross, M. C.; Roukes, M. L.

    2013-01-01

    In its most basic form an oscillator consists of a resonator driven on resonance, through feedback, to create a periodic signal sustained by a static energy source. The generation of a stable frequency, the basic function of oscillators, is typically achieved by increasing the amplitude of motion of the resonator while remaining within its linear, harmonic regime. Contrary to this conventional paradigm, in this Letter we show that by operating the oscillator at special points in the resonator’s anharmonic regime we can overcome fundamental limitations of oscillator performance due to thermodynamic noise as well as practical limitations due to noise from the sustaining circuit. We develop a comprehensive model that accounts for the major contributions to the phase noise of the nonlinear oscillator. Using a nano-electromechanical system based oscillator, we experimentally verify the existence of a special region in the operational parameter space that enables suppressing the most significant contributions to the oscillator’s phase noise, as predicted by our model. PMID:23679770

  2. Tables of Shore and Fano parameters for the helium resonances 2s/sup 2/ /sup 1/S, 2p/sup 2/ /sup 1/D, and 2s 2p /sup 1/P excited in p-He collisions E/sub p/ = 33 to 150 keV

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A.; Merchez, H.

    1976-02-01

    Absolute values of Shore and Fano parameters are tabulated for the helium atom 2s/sup 2/ /sup 1/S, 2p/sup 2/ /sup 1/D, and 2s 2p /sup 1/P resonances produced by a proton beam. Observations were made on the spectra of ejected electrons. The important variation of the shape of the resonances with ejection angle is illustrated for E/sub p/ = 100 keV; the variation with proton energy is shown at 30/sup 0/.

  3. Nonlinear dynamic response of beam and its application in nanomechanical resonator

    Institute of Scientific and Technical Information of China (English)

    Yin Zhang; Yun Liu; Kevin D. Murphy

    2012-01-01

    Nonlinear dynamic response of nanomechanical resonator is of very important characteristics in its application.Two categories of the tension-dominant and curvaturedominant nonlinearities are analyzed.The dynamic nonlinearity of four beam structures of nanomechanical resonator is quantitatively studied via a dimensional analysis approach.The dimensional analysis shows that for the nanomechanical resonator of tension-dominant nonlinearity,its dynamic nonlinearity decreases monotonically with increasing axial loading and increases monotonically with the increasing aspect ratio of length to thickness; the dynamic nonlinearity can only result in the hardening effects.However,for the nanomechanical resonator of the curvature-dominant nonlinearity,its dynamic nonlinearity is only dependent on axial loading.Compared with the tension-dominant nonlinearity,the curvature-dominant nonlinearity increases monotonically with increasing axial loading; its dynamic nonlinearity can result in both hardening and softening effects.The analysis on the dynamic nonlinearity can be very helpful to the tuning application of the nanomechanical resonator.

  4. Optimal operating points of oscillators using nonlinear resonators.

    Science.gov (United States)

    Kenig, Eyal; Cross, M C; Villanueva, L G; Karabalin, R B; Matheny, M H; Lifshitz, Ron; Roukes, M L

    2012-11-01

    We demonstrate an analytical method for calculating the phase sensitivity of a class of oscillators whose phase does not affect the time evolution of the other dynamic variables. We show that such oscillators possess the possibility for complete phase noise elimination. We apply the method to a feedback oscillator which employs a high Q weakly nonlinear resonator and provide explicit parameter values for which the feedback phase noise is completely eliminated and others for which there is no amplitude-phase noise conversion. We then establish an operational mode of the oscillator which optimizes its performance by diminishing the feedback noise in both quadratures, thermal noise, and quality factor fluctuations. We also study the spectrum of the oscillator and provide specific results for the case of 1/f noise sources.

  5. Optimization of nonlinear structural resonance using the incremental harmonic balance method

    DEFF Research Database (Denmark)

    Dou, Suguang; Jensen, Jakob Søndergaard

    2015-01-01

    We present an optimization procedure for tailoring the nonlinear structural resonant response with time-harmonic loads. A nonlinear finite element method is used for modeling beam structures with a geometric nonlinearity and the incremental harmonic balance method is applied for accurate nonlinea...

  6. Lorentz meets Fano spectral line shapes: A universal phase and its laser control

    CERN Document Server

    Ott, Christian; Raith, Philipp; Meyer, Kristina; Laux, Martin; Evers, Jörg; Keitel, Christoph H; Greene, Chris H; Pfeifer, Thomas

    2013-01-01

    Symmetric Lorentzian and asymmetric Fano line shapes are fundamental spectroscopic signatures that quantify the structural and dynamical properties of nuclei, atoms, molecules, and solids. This study introduces a universal temporal-phase formalism, mapping the Fano asymmetry parameter q to a phase {\\phi} of the time-dependent dipole-response function. The formalism is confirmed experimentally by laser-transforming Fano absorption lines of autoionizing helium into Lorentzian lines after attosecond-pulsed excitation. We also prove the inverse, the transformation of a naturally Lorentzian line into a Fano profile. A further application of this formalism amplifies resonantly interacting extreme-ultraviolet light by quantum-phase control. The quantum phase of excited states and its response to interactions can thus be extracted from line-shape analysis, with scientific applications in many branches of spectroscopy.

  7. Mediating Fano losses in plasmonic scatterers by tuning the dielectric environment

    Science.gov (United States)

    Powell, A. W.; Smith, J. M.

    2016-09-01

    Scattering from metal nanoparticles above a high index substrate has the potential to significantly enhance light trapping in thin film devices with minimal additional cost. However, the benefits of this approach are currently limited by short wavelength losses from Fano resonances arising due to interference between the plasmon modes in a nanoparticle. In this paper, the effect of particle-substrate interactions on the observed Fano behaviour is explored in detail, using finite-difference time-domain simulations and an analytical model. Several approaches to mitigate the Fano loss are explored, and it is found that overcoating the particle with a thin dielectric film represents by far the most effective way to remove Fano losses whilst keeping broadband forward scattering high.

  8. Two-oscillator model of trapped-modes interaction in a nonlinear bilayer fish-scale metamaterial

    CERN Document Server

    Tuz, Vladimir R; Kochetova, Lyudmila A; Mladyonov, Pavel L; Prosvirnin, Sergey L

    2014-01-01

    We discuss the similarity between the nature of resonant oscillations in two nonlinear systems, namely, a chain of coupled Duffing oscillators and a bilayer fish-scale metamaterial. In such systems two different resonant states arise which differ in their spectral lines. The spectral line of the first resonant state has a Lorentzian form, while the second one has a Fano form. This difference leads to a specific nonlinear response of the systems which manifests itself in appearance of closed loops in spectral lines and bending and overlapping of resonant curves. Conditions of achieving bistability and multistability are found out.

  9. Nonlinear magnetization dynamics of antiferromagnetic spin resonance induced by intense terahertz magnetic field

    CERN Document Server

    Mukai, Y; Yamamoto, T; Kageyama, H; Tanaka, K

    2016-01-01

    We report on the nonlinear magnetization dynamics of a HoFeO3 crystal induced by a strong terahertz magnetic field resonantly enhanced with a split ring resonator and measured with magneto-optical Kerr effect microscopy. The terahertz magnetic field induces a large change (~40%) in the spontaneous magnetization. The frequency of the antiferromagnetic resonance decreases in proportion to the square of the magnetization change. A modified Landau-Lifshitz-Gilbert equation with a phenomenological nonlinear damping term quantitatively reproduced the nonlinear dynamics.

  10. Nonlinear thickness-stretch vibration of thin-film acoustic wave resonators

    Science.gov (United States)

    Ji, Xiaojun; Fan, Yanping; Han, Tao; Cai, Ping

    2016-03-01

    We perform a theoretical analysis on nonlinear thickness-stretch free vibration of thin-film acoustic wave resonators made from AlN and ZnO. The third-order or cubic nonlinear theory by Tiersten is employed. Using Green's identify, under the usual approximation of neglecting higher time harmonics, a perturbation analysis is performed from which the resonator frequency-amplitude relation is obtained. Numerical calculations are made. The relation can be used to determine the linear operating range of these resonators. It can also be used to compare with future experimental results to determine the relevant thirdand/or fourth-order nonlinear elastic constants.

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

    KAUST Repository

    Amin, Muhammad

    2014-01-01

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

  12. Enhanced linear and nonlinear optical phase response of AlGaAs microring resonators.

    Science.gov (United States)

    Heebner, John E; Lepeshkin, Nick N; Schweinsberg, Aaron; Wicks, G W; Boyd, Robert W; Grover, Rohit; Ho, P T

    2004-04-01

    We have constructed and characterized several optical microring resonators with scale sizes of the order of 10 microm. These devices are intended to serve as building blocks for engineerable linear and nonlinear photonic media. Light is guided vertically by an epitaxially grown structure and transversely by deeply etched air-clad sidewalls. We report on the spectral phase transfer characteristics of such resonators. We also report the observation of a pi-rad Kerr nonlinear phase shift accumulated in a single compact ring resonator evidenced by all-optical switching between output ports of a resonator-enhanced Mach-Zehnder interferometer.

  13. Measurement of nonlinear elastic response in rock by the resonant bar method

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, P.A. [Los Alamos National Lab., NM (United States); Rasolofosaon, P.; Zinszner, B. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France)

    1993-04-01

    In this work we are studying the behavior of the fundamental (Young`s) mode resonant peak as a function of drive amplitude in rock samples. Our goal from these studies is to obtain nonlinear moduli for many rock types, and to study the nonlinear moduli as a function of water saturation and other changes in physical properties. Measurements were made on seven different room dry rock samples. For one sample measurements were taken at 16 saturation levels between 1 and 98%. All samples display a ``softening`` nonlinearity, that is, the resonant frequency shifts downward with increasing drive amplitude. In extreme cases, the resonant frequency changes by as much as 25% over a strain interval of 10{sup {minus}7} to {approximately}4 {times} 10{sup {minus}5}. Measurements indicate that the nonlinear response is extremely sensitive to saturation. Estimates of a combined cubic and quartic nonlinear parameter {Gamma} range from approximately {minus}300 to {minus}10{sup 9} for the rock samples.

  14. A new nonlinear model for analyzing the behaviour of carbon nanotube-based resonators

    Science.gov (United States)

    Farokhi, Hamed; Païdoussis, Michael P.; Misra, Arun K.

    2016-09-01

    The present study develops a new size-dependent nonlinear model for the analysis of the behaviour of carbon nanotube-based resonators. In particular, based on modified couple stress theory, the fully nonlinear equations of motion of the carbon nanotube-based resonator are derived using Hamilton's principle, taking into account both the longitudinal and transverse displacements. Molecular dynamics simulation is then performed in order to verify the validity of the developed size-dependent continuum model at the nano scale. The nonlinear partial differential equations of motion of the system are discretized by means of the Galerkin technique, resulting in a high-dimensional reduced-order model of the system. The pseudo-arclength continuation technique is employed to examine the nonlinear resonant behaviour of the carbon nanotube-based resonator. A new universal pull-in formula is also developed for predicting the occurrence of the static pull-in and validated using numerical simulations.

  15. Slow light enhanced optical nonlinearity in a silicon photonic crystal coupled-resonator optical waveguide.

    Science.gov (United States)

    Matsuda, Nobuyuki; Kato, Takumi; Harada, Ken-Ichi; Takesue, Hiroki; Kuramochi, Eiichi; Taniyama, Hideaki; Notomi, Masaya

    2011-10-10

    We demonstrate highly enhanced optical nonlinearity in a coupled-resonator optical waveguide (CROW) in a four-wave mixing experiment. Using a CROW consisting of 200 coupled resonators based on width-modulated photonic crystal nanocavities in a line defect, we obtained an effective nonlinear constant exceeding 10,000 /W/m, thanks to slow light propagation combined with a strong spatial confinement of light achieved by the wavelength-sized cavities.

  16. Application of Nonlinear Elastic Resonance Spectroscopy For Damage Detection In Concrete: An Interesting Story

    Energy Technology Data Exchange (ETDEWEB)

    Byers, Loren W. [Los Alamos National Laboratory; Ten Cate, James A. [Los Alamos National Laboratory; Johnson, Paul A. [Los Alamos National Laboratory

    2012-06-28

    Nonlinear resonance ultrasound spectroscopy experiments conducted on concrete cores, one chemically and mechanically damaged by alkali-silica reactivity, and one undamaged, show that this material displays highly nonlinear wave behavior, similar to many other damaged materials. They find that the damaged sample responds more nonlinearly, manifested by a larger resonant peak and modulus shift as a function of strain amplitude. The nonlinear response indicates that there is a hysteretic influence in the stress-strain equation of state. Further, as in some other materials, slow dynamics are present. The nonlinear response they observe in concrete is an extremely sensitive indicator of damage. Ultimately, nonlinear wave methods applied to concrete may be used to guide mixing, curing, or other production techniques, in order to develop materials with particular desired qualities such as enhanced strength or chemical resistance, and to be used for damage inspection.

  17. Modeling of racetrack-resonator add-drop filters with arbitrary nonlinear directional couplers.

    Science.gov (United States)

    Gómez-Alcalá, Rafael; Fraile-Peláez, F Javier; Chamorro-Posada, Pedro; Díaz-Otero, Francisco J

    2012-06-01

    In this Letter we employ the general coupled-mode equations of the nonlinear directional coupler and demonstrate that the switching characteristics of prototypical nonlinear racetrack-resonator structures may differ considerably from those obtained when the standard, generally incorrect, coupled-mode equations are used.

  18. Slow light, induced dispersion, enhanced nonlinearity, and optical solitons in a resonator-array waveguide.

    Science.gov (United States)

    E Heebner, John; Boyd, Robert W; Park, Q-Han

    2002-03-01

    We describe an optical transmission line that consists of an array of wavelength-scale optical disk resonators coupled to an optical waveguide. Such a structure leads to exotic optical characteristics, including ultraslow group velocities of propagation, enhanced optical nonlinearities, and large dispersion with a controllable magnitude and sign. This device supports soliton propagation, which can be described by a generalized nonlinear Schrodinger equation.

  19. Nonlinear effects in acoustic metamaterial based on a cylindrical pipe with ordered Helmholtz resonators

    Science.gov (United States)

    Lan, Jun; Li, Yifeng; Yu, Huiyang; Li, Baoshun; Liu, Xiaozhou

    2017-04-01

    We theoretically investigate the nonlinear effects of acoustic wave propagation and dispersion in a cylindrical pipe with periodically arranged Helmholtz resonators. By using the classical perturbation method in nonlinear acoustics and considering a nonlinear response up to the third-order at the fundamental frequency, the expressions of the nonlinear impedance ZNHR of the Helmholtz resonator and effective nonlinear bulk modulus Bneff of the composite structure are derived. In order to confirm the nonlinear properties of the acoustic metamaterial, the transmission spectra have been studied by means of the acoustic transmission line method. Moreover, we calculate the effective acoustic impedance and dispersion relation of the system using the acoustic impedance theory and Bloch theory, respectively. It is found that with the increment of the incident acoustic pressure level, owing to the nonlinearity of the Helmholtz resonators, the resonant frequency ω0 shifts toward the lower frequency side and the forbidden bandgap of the transmission spectrum is shown to be broadened. The perturbation method employed in this paper extends the general analytical framework for a nonlinear acoustic metamaterial.

  20. Long wave-short wave resonance in nonlinear negative refractive index media.

    Science.gov (United States)

    Chowdhury, Aref; Tataronis, John A

    2008-04-18

    We show that long wave-short wave resonance can be achieved in a second-order nonlinear negative refractive index medium when the short wave lies on the negative index branch. With the medium exhibiting a second-order nonlinear susceptibility, a number of nonlinear phenomena such as solitary waves, paired solitons, and periodic wave trains are possible or enhanced through the cascaded second-order effect. Potential applications include the generation of terahertz waves from optical pulses.

  1. Influence of resonator shape on nonlinear acoustic field in a thermoacoustic engine

    Institute of Scientific and Technical Information of China (English)

    LIU Danxiao; ZHOU Chengguang; LIU Ke

    2012-01-01

    The influence of the resonator shape on nonlinear acoustic field in a thermoacous- tic engine is studied. The resonator of themoacoustic engine is boundary driving by a piston at one end, and the other end of it is rigid closed. A one-dimensional wave equation that accounts for gas dynamic nonlinearities and viscous dissipation in the resonator is established based on the governing equations of viscous hydromechanics. The nonlinear wave equation is solved using approximate Galerkin method. The nonlinear acoustic field in four different types of shaped resonators including hyperbolical, exponential, conical and sinusoidal are obtained and compared with that of a cylindrical resonator. It is found that the amplitude and wave- form of the pressure are strongly affected by the resonator shape, the driving amplitude and the oscillation frequency of the piston. Waveform distortion, resonance frequency shift and hysteresis are observed, when the piston oscillation amplitude is large enough. The advantages of shaped resonator for thermoacoustic engine lie in inhibition of higher order harmonics and improvement of pressure ratio, etc.

  2. Coherent perfect absorption induced by the nonlinearity of a Helmholtz resonator.

    Science.gov (United States)

    Achilleos, V; Richoux, O; Theocharis, G

    2016-07-01

    In this work, coherent perfect absorption of sound waves induced by the nonlinear response of a Helmholtz Resonator side loaded to a waveguide, is reported. It is shown that this two-port system can perfectly absorb two high amplitude symmetric incident waves under a certain condition. For the one-sided incidence configuration, this condition leads to an absorption equal to 0.5. Experiments verify these results and are in agreement with an analytical nonlinear impedance model for the resonator. The nonlinear control of perfect absorption opens new possibilities in the design of high amplitude sound attenuators for aero-engine applications.

  3. Nonlinear resonance phenomena of a doped fibre laser under cavity-loss modulation: Experimental demonstrations

    Indian Academy of Sciences (India)

    A Ghosh; B K Goswami; R Vijaya

    2010-11-01

    Our experiments with an erbium-doped fibre ring laser (CW, single transverse mode and multiaxial mode) with an intracavity LiNbO3 electro-optic modulator (EOM) display the characteristic features of a nonlinear oscillator (e.g., harmonic and period-2 sub-harmonic resonances) when the EOM driver voltage is modulated periodically. Harmonic resonance leads to period-1 bistability and hysteresis. Inside the period-2 sub-harmonic resonance region, the laser exhibits Feigenbaum sequence and generalized bistability.

  4. NERO: a code for the nonlinear evaluation of resonances in one-turn mappings

    Science.gov (United States)

    Todesco, E.; Gemmi, M.; Giovannozzi, M.

    1997-10-01

    We describe a code that evaluates the stability, the position and the width of resonances in four-dimensional symplectic mappings. The code is based on the computation of the resonant perturbative series through the program ARES, and on the analysis of the resonant orbits of the interpolating Hamiltonian. The code is dedicated to the study and to the comparison of the nonlinear behaviour in one-turn betatronic maps.

  5. 1:2 INTERNAL RESONANCE OF COUPLED DYNAMIC SYSTEM WITH QUADRATIC AND CUBIC NONLINEARITIES

    Institute of Scientific and Technical Information of China (English)

    陈予恕; 杨彩霞; 吴志强; 陈芳启

    2001-01-01

    The 1:2 internal resonance of coupled dynamic system with quadratic and cubic nonlinearities is studied. The normal forms of this system in 1: 2 internal resonance were derived by using the direct method of normal form. In the normal forms, quadratic and cubic nonlinearities were remained. Based on a new convenient transformation technique, the 4-dimension bifurcation equations were reduced to 3-dimension. A bifurcation equation with one-dimension was obtained. Then the bifurcation behaviors of a universal unfolding were studied by using the singularity theory. The method of this paper can be applied to analyze the bifurcation behavior in strong internal resonance on 4-dimension center manifolds.

  6. Laser-Machined Ultra-High-Q Microrod Resonators for Nonlinear Optics

    CERN Document Server

    Del'Haye, Pascal; Papp, Scott B

    2013-01-01

    Optical whispering-gallery microresonators are useful tools in microphotonics, and nonlinear optics at very low threshold powers. Here, we present details about the fabrication of ultra-high-Q whispering-gallery-mode resonators made by CO2-laser lathe machining of fused-quartz rods. The resonators can be fabricated in less than one minute and the obtained optical quality factors exceed Q = 10^9. Demonstrated resonator diameters are in the range between 170 {\\mu}m and 8 mm (free spectral ranges between 390 GHz and 8 GHz). Using these microresonators, a variety of optical nonlinearities are observed, including Raman scattering, Brillouin scattering and four-wave mixing.

  7. Ultrafast optical control using the Kerr nonlinearity in hydrogenated amorphous silicon microcylindrical resonators

    Science.gov (United States)

    Vukovic, N.; Healy, N.; Suhailin, F. H.; Mehta, P.; Day, T. D.; Badding, J. V.; Peacock, A. C.

    2013-10-01

    Microresonators are ideal systems for probing nonlinear phenomena at low thresholds due to their small mode volumes and high quality (Q) factors. As such, they have found use both for fundamental studies of light-matter interactions as well as for applications in areas ranging from telecommunications to medicine. In particular, semiconductor-based resonators with large Kerr nonlinearities have great potential for high speed, low power all-optical processing. Here we present experiments to characterize the size of the Kerr induced resonance wavelength shifting in a hydrogenated amorphous silicon resonator and demonstrate its potential for ultrafast all-optical modulation and switching. Large wavelength shifts are observed for low pump powers due to the high nonlinearity of the amorphous silicon material and the strong mode confinement in the microcylindrical resonator. The threshold energy for switching is less than a picojoule, representing a significant step towards advantageous low power silicon-based photonic technologies.

  8. Collective resonances of atomic xenon from the linear to the nonlinear regime

    CERN Document Server

    Chen, Yi-Jen; Santra, Robin

    2016-01-01

    We explain the origin of the two collective sub-resonances of the $4d$ giant dipole resonance of atomic Xe recently discovered by nonlinear spectroscopy. In the case of one-photon absorption, while a change in the resonant-like feature in the cross section upon the inclusion of electronic correlations has been commonly attributed to a change of the resonance parameters of a single resonance state, we show that this modification is a result of switching between the relative visibilities of the underlying resonance states. In addition, we predict hitherto undiscovered collective $4d$ resonance states in Xe that can only be accessed through multiphoton absorption. Unlike any known collective feature in atoms, these resonances are exceptionally long-lived (more than 100 attoseconds), thus opening up possibilities to probe new collective effects in atoms with modern XUV light sources.

  9. Surpassing Fundamental Limits of Oscillators Using Nonlinear Resonators

    OpenAIRE

    Villanueva, L. G.; Kenig, E.; Karabalin, R. B.; Matheny, M. H.; Lifshitz, R; Cross, M. C.; Roukes, M. L.

    2013-01-01

    Self-sustained oscillators are ubiquitous and essential for metrology, communications, time reference, and geolocation. In its most basic form an oscillator consists of a resonator driven on-resonance, through feedback, to create a periodic signal sustained by a static energy source. The generation of a stable frequency, the basic function of oscillators, is typically achieved by increasing the amplitude of motion of the resonator while remaining within its linear, harmonic, regime. Contrary ...

  10. Plasmon resonance enhancement of nonlinear properties of amino acids

    Science.gov (United States)

    de Araujo, Renato E.; Rativa, Diego; Gomes, Anderson S. L.

    2007-02-01

    Here we analyze the influence of 9 nm (mean diameter) silver particles on the nonlinear properties of intrinsic cell molecules. A novel high sensitivity thermal managed eclipse Z-scan technique with a femtosecond laser system was used to analyze the nonlinear susceptibility of water solution of fluorescent and non-fluorescent amino acids (Tryptophan, Tyrosine, Phenylalanine, Proline and Histidine) with different concentration of silver nanoparticles. The generalized Maxwell Garnett model is used to explain the behavior of the measured nonlinear refractive index with the change of the nanoparticles concentration in the sample.

  11. Shear dependent nonlinear vibration in a high quality factor single crystal silicon micromechanical resonator

    Science.gov (United States)

    Zhu, H.; Shan, G. C.; Shek, C. H.; Lee, J. E.-Y.

    2012-07-01

    The frequency response of a single crystal silicon resonator under nonlinear vibration is investigated and related to the shear property of the material. The shear stress-strain relation of bulk silicon is studied using a first-principles approach. By incorporating the calculated shear property into a device-level model, our simulation closely predicts the frequency response of the device obtained by experiments and further captures the nonlinear features. These results indicate that the observed nonlinearity stems from the material's mechanical property. Given the high quality factor (Q) of the device reported here (˜2 × 106), this makes it highly susceptible to such mechanical nonlinear effects.

  12. Analysis of factors influencing fire damage to concrete using nonlinear resonance vibration method

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gang Kyu; Park, Sun Jong; Kwak, Hyo Gyoung [Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, KAIST, Daejeon (Korea, Republic of); Yim, Hong Jae [Dept. of Construction and Disaster Prevention Engineering, Kyungpook National University, Sangju (Korea, Republic of)

    2015-04-15

    In this study, the effects of different mix proportions and fire scenarios (exposure temperatures and post-fire-curing periods) on fire-damaged concrete were analyzed using a nonlinear resonance vibration method based on nonlinear acoustics. The hysteretic nonlinearity parameter was obtained, which can sensitively reflect the damage level of fire-damaged concrete. In addition, a splitting tensile strength test was performed on each fire-damaged specimen to evaluate the residual property. Using the results, a prediction model for estimating the residual strength of fire-damaged concrete was proposed on the basis of the correlation between the hysteretic nonlinearity parameter and the ratio of splitting tensile strength.

  13. Nonlinear resonances of three modes in a high-T{sub c} superconducting magnetic levitation system

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Masahiko, E-mail: galian@z2.keio.jp; Sakaguchi, Ryunosuke; Sugiura, Toshihiko, E-mail: sugiura@mach.keio.ac.jp

    2013-11-15

    Highlights: •We studied two nonlinear vibrations of a levitated beam supported by superconductors. •One of the vibrations is combination resonance of the 1st mode and the 3rd mode. •The other vibration is autoparametric resonance of the 2nd mode. •When the amplitude of the 2nd mode is small, the combination resonance is suppressed. •Otherwise, the two resonances can be resonated simultaneously. -- Abstract: In a high-T{sub c} superconducting magnetic levitation system, an object can levitate without control and contact. So it is expected to be applied to magnetically levitated transportation. To use it safely, lightening the levitated object is necessary. But this reduces the bending stiffness of the object. Besides, the system has nonlinearity. Therefore nonlinear elastic vibration can occur. This study focused on how plural nonlinear elastic vibrations of the 1st, 2nd and 3rd modes simultaneously occur. Our numerical calculation and experiment found out that the three modes simultaneously resonate when the amplitude of the 2nd mode is large enough whereas only the 2nd mode resonates when it is small.

  14. Fano effect and Andreev bound states in a hybrid superconductor–ferromagnetic nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, E.C., E-mail: ezcostta@gmail.com [Departamento de Física, Universidade Tecnológica Federal do Paraná – UTFPR, 84016210, Ponta Grossa, PR (Brazil); Orellana, P.A. [Departamento de Física, Universidad Técnica Federico Santa Maria, Av. Vicuña Mackenna 3939, Santiago (Chile); Cestari, R.C. [Departamento de Física e Química, Universidade Estadual Paulista – UNESP, 15385-000, Ilha Solteira, SP (Brazil); Figueira, M.S. [Instituto de Física, Universidade Federal Fluminense, 24210-340, Niterói, RJ (Brazil); Cabrera, G.G. [Instituto de Física ‘Gleb Wataghin’, Universidade Estadual de Campinas – UNICAMP, Campinas 13083-859, SP (Brazil)

    2015-10-16

    In this work, it is considered a hybrid nanostructure composed by a quantum dot coupled to two ferromagnetic leads and a superconductor lead. It is shown that the zero-bias transmittance for the co-tunneling between the ferromagnetic leads presents Fano anti-resonances due to the destructive interference between the two spin channels mixing by the relative orientation of the magnetizations in the leads. When the superconductor is coupled to the system, electron–hole correlations between different spin states lead to a resonance in the place of the dip appearing in the transmittance. Such an effect is accompanied by two Fano anti-resonances explained by a “leakage” of conduction channels from the co-tunneling to the Andreev transport. In the non-equilibrium regime, correlations within the quantum dot introduce a dependence of the resonance condition on the finite bias applied to the ferromagnetic leads. However, it is still possible to observe signatures of the same interference effect in the electrical current. - Highlights: • We have studied an hybrid nanostructure composed by quantum dot coupled to a superconductor and two ferromagnets. • The interplay between spin polarization and Andreev bound states leads to a Fano-like effect. • The Fano-like effect manifests as a resonance in the transmittance for the transport between the ferromagnets.

  15. Mechanism of geometric nonlinearity in a nonprismatic and heterogeneous microbeam resonator

    Science.gov (United States)

    Asadi, Keivan; Li, Junfeng; Peshin, Snehan; Yeom, Junghoon; Cho, Hanna

    2017-09-01

    Implementation of geometric nonlinearity in microelectromechanical systems (MEMS) resonators offers a flexible and efficient design to overcome the limitations of linear MEMS by utilizing beneficial nonlinear characteristics not attainable in a linear setting. Integration of nonlinear coupling elements into an otherwise purely linear microcantilever is one promising way to intentionally realize geometric nonlinearity. Here, we demonstrate that a nonlinear, heterogeneous microresonator system, consisting of a silicon microcantilever with a polymer attachment exhibits strong nonlinear hardening behavior not only in the first flexural mode but also in the higher modes (i.e., second and third flexural modes). In this design, we deliberately implement a drastic and reversed change in the axial vs bending stiffness between the Si and polymer components by varying the geometric and material properties. By doing so, the resonant oscillations induce the large axial stretching within the polymer component, which effectively introduces the geometric stiffness and damping nonlinearity. The efficacy of the design and the mechanism of geometric nonlinearity are corroborated through a comprehensive experimental, analytical, and numerical (finite element) analysis on the nonlinear dynamics of the proposed system.

  16. Resonant interactions between discrete phonons in quinhydrone driven by nonlinear electron-phonon coupling

    Science.gov (United States)

    Rury, Aaron S.

    2016-06-01

    This study reports experimental, computational, and theoretical evidence for a previously unobserved coherent phonon-phonon interaction in an organic solid that can be described by the application of Fano's analysis to a case without the presence of a continuum. Using Raman spectroscopy of the hydrogen-bonded charge-transfer material quinhydrone, two peaks appear near 700 cm-1 we assign as phonons whose position and line-shape asymmetry depend on the sample temperature and light scattering excitation energy. Density functional theory calculations find two nearly degenerate phonons possessing frequencies near the values found in experiment that share similar atomic motion out of the aromatic plane of electron donor and acceptor molecules of quinhydrone. Further analytical modeling of the steady-state light scattering process using the Peierls-Hubbard Hamiltonian and time-dependent perturbation theory motivates assignment of the physical origin of the asymmetric features of each peak's line shape to an interaction between two discrete phonons via nonlinear electron-phonon coupling. In the context of analytical model results, characteristics of the experimental spectra upon 2.33 eV excitation of the Raman scattering process are used to qualify the temperature dependence of the magnitude of this coupling in the valence band of quinhydrone. These results broaden the range of phonon-phonon interactions in materials in general while also highlighting the rich physics and fundamental attributes specific to organic solids that may determine their applicability in next generation electronics and photonics technologies.

  17. High amplitude nonlinear acoustic wave driven flow fields in cylindrical and conical resonators.

    Science.gov (United States)

    Antao, Dion Savio; Farouk, Bakhtier

    2013-08-01

    A high fidelity computational fluid dynamic model is used to simulate the flow, pressure, and density fields generated in a cylindrical and a conical resonator by a vibrating end wall/piston producing high-amplitude standing waves. The waves in the conical resonator are found to be shock-less and can generate peak acoustic overpressures that exceed the initial undisturbed pressure by two to three times. A cylindrical (consonant) acoustic resonator has limitations to the output response observed at one end when the opposite end is acoustically excited. In the conical geometry (dissonant acoustic resonator) the linear acoustic input is converted to high energy un-shocked nonlinear acoustic output. The model is validated using past numerical results of standing waves in cylindrical resonators. The nonlinear nature of the harmonic response in the conical resonator system is further investigated for two different working fluids (carbon dioxide and argon) operating at various values of piston amplitude. The high amplitude nonlinear oscillations observed in the conical resonator can potentially enhance the performance of pulse tube thermoacoustic refrigerators and these conical resonators can be used as efficient mixers.

  18. Electrically actuated MEMS resonators: Effects of fringing field and nonlinear viscoelasticity

    Science.gov (United States)

    Farokhi, Hamed; Ghayesh, Mergen H.

    2017-10-01

    This paper studies the nonlinear electromechanical response of a MEMS resonator numerically. A nonlinear continuous multi-physics model of the MEMS resonator is developed taking into account the effects of fringing field, size, residual axial load, and viscoelasticity. Moreover, both longitudinal and transverse motions are accounted for in the system modelling and simulations. The equations of motion of the MEMS resonator are obtained employing Hamilton's principle together with the modified version of the couple stress based theory (to account for size effects) and the Kelvin-Voigt model (to account for nonlinear energy dissipation). The Meijs-Fokkema electrostatic load formula is used to reliably model the fringing field effects. The continuous multi-physics model, consisting of geometrical, electrical, and viscos nonlinearities is discretised via a weighted-residual method, yielding a set of nonlinearly coupled ordinary differential equations (ODEs). The resultant set of ODEs is solved numerically when the microresonator is actuated by a biased DC voltage and an AC voltage. The results of the numerical simulations are presented in the form of DC voltage-deflection, DC voltage-natural frequency, and AC frequency-displacement diagrams. The effects of fringing field, residual axial load, small-scale, and nonlinear energy dissipation are highlighted. It is shown that fringing field effects are significant on both static and dynamic electromechanical responses of the MEMS resonator.

  19. Double-dark-resonance-enhanced Kerr nonlinearity in a single layer of graphene nanostructure

    Science.gov (United States)

    Solookinejad, Gh.; Panahi, M.; Ahmadi Sangachin, E.; Hossein Asadpour, Seyyed

    2016-08-01

    In this paper, a novel scheme is proposed for the giant enhanced Kerr nonlinearity in a single layer of graphene nanostructure based on quantum optics and nonlinear optical sciences. The linear and the nonlinear susceptibility of the monolayer graphene system are presented in details by using the density matrix method and perturbation theory. After deriving the equations of motion in the steady-state regime, we analytically solve the linear and nonlinear susceptibility of the system. Our numerical results show that the giant enhanced Kerr nonlinearity can be obtained in the double-dark-resonance condition with zero linear and nonlinear absorption. Our results may have potential applications in quantum information science in infrared and terahertz regimes.

  20. Nonlinear elliptic equations and systems with linear part at resonance

    Directory of Open Access Journals (Sweden)

    Philip Korman

    2016-03-01

    Full Text Available The famous result of Landesman and Lazer [10] dealt with resonance at a simple eigenvalue. Soon after publication of [10], Williams [14] gave an extension for repeated eigenvalues. The conditions in Williams [14] are rather restrictive, and no examples were ever given. We show that seemingly different classical result by Lazer and Leach [11], on forced harmonic oscillators at resonance, provides an example for this theorem. The article by Williams [14] also contained a shorter proof. We use a similar approach to study resonance for 2X2 systems. We derive conditions for existence of solutions, which turned out to depend on the spectral properties of the linear part.

  1. Fano interference in two-photon transport

    Science.gov (United States)

    Xu, Shanshan; Fan, Shanhui

    2016-10-01

    We present a general input-output formalism for the few-photon transport in multiple waveguide channels coupled to a local cavity. Using this formalism, we study the effect of Fano interference in two-photon quantum transport. We show that the physics of Fano interference can manifest as an asymmetric spectral line shape in the frequency dependence of the two-photon correlation function. The two-photon fluorescence spectrum, on the other hand, does not exhibit the physics of Fano interference.

  2. Numerical modeling of nonlinear acoustic waves in a tube with an array of Helmholtz resonators

    CERN Document Server

    Lombard, Bruno

    2013-01-01

    Wave propagation in a 1-D guide with an array of Helmholtz resonators is studied numerically, considering large amplitude waves and viscous boundary layers. The model consists in two coupled equations: a nonlinear PDE of nonlinear acoustics, and a linear ODE describing the oscillations in the Helmholtz resonators. The dissipative effects in the tube and in the throats of the resonators are modeled by fractional derivatives. Based on a diffusive representation, the convolution kernels are replaced by a finite number of memory variables that satisfy local ordinary differential equations. An optimization procedure provides an efficient diffusive representation. A splitting strategy is then applied to the evolution equations: the propagative part is solved by a standard TVD scheme for hyperbolic equations, whereas the diffusive part is solved exactly. This approach is validated by comparisons with exact solutions. The properties of the full nonlinear solutions are investigated numerically. In particular, existenc...

  3. PRINCIPAL RESONANCE IN TRANSVERSE NONLINEAR PARAMETRIC VIBRATION OF AN AXIALLY ACCELERATING VISCOELASTIC STRING

    Institute of Scientific and Technical Information of China (English)

    CHEN Liqun; Jean W.ZU; WU Jun

    2004-01-01

    To investigate the principal resonance in transverse nonlinear parametric vibration of an axially accelerating viscoelastic string, the method of multiple scales is applied directly to the nonlinear partial differential equation that governs the transverse vibration of the string. To derive the governing equation, Newton's second law, Lagrangean strain, and Kelvin's model are respectively used to account the dynamical relation, geometric nonlinearity and the viscoelasticity of the string material.Based on the solvability condition of eliminating the secular terms, closed form solutions are obtained for the amplitude and the existence conditions of nontrivial steady-state response of the principal parametric resonance. The Lyapunov linearized stability theory is employed to analyze the stability of the trivial and nontrivial solutions in the principal parametric resonance. Some numerical examples are presented to show the effects of the mean transport speed, the amplitude and the frequency of speed variation.

  4. Aluminum for nonlinear plasmonics: resonance-driven polarized luminescence of Al, Ag, and Au nanoantennas.

    Science.gov (United States)

    Castro-Lopez, Marta; Brinks, Daan; Sapienza, Riccardo; van Hulst, Niek F

    2011-11-09

    Resonant optical antennas are ideal for nanoscale nonlinear optical interactions due to their inherent strong local field enhancement. Indeed second- and third-order nonlinear response of gold nanoparticles has been reported. Here we compare the on- and off-resonance properties of aluminum, silver, and gold nanoantennas, by measuring two-photon photoluminescence. Remarkably, aluminum shows 2 orders of magnitude higher luminescence efficiency than silver or gold. Moreover, in striking contrast to gold, the aluminum emission largely preserves the linear incident polarization. Finally, we show the systematic resonance control of two-photon excitation and luminescence polarization by tuning the antenna width and length independently. Our findings point to aluminum as a promising metal for nonlinear plasmonics.

  5. All-plasmonic switching based on thermal nonlinearity in a polymer plasmonic microring resonator

    Science.gov (United States)

    Perron, David; Wu, Marcelo; Horvath, Cameron; Bachman, Daniel; van, Vien

    2011-07-01

    We experimentally investigated thermal nonlinear effects in a hybrid Au/SiO2/SU-8 plasmonic microring resonator for nonlinear switching. Large ohmic loss in the metal layer gave rise to a high rate of light-to-heat conversion in the plasmonic waveguide, causing an intensity-dependent thermo-optic shift in the microring resonance. We obtained 30 times larger resonance shift in the plasmonic microring than in a similar SU-8 dielectric microring. Using an in-plane pump-and-probe configuration, we also demonstrated all-plasmonic nonlinear switching in the plasmonic microring with an on--off switching contrast of 4dB over 50mW input power.

  6. Compact surface Fano states embedded in the continuum of waveguide arrays

    CERN Document Server

    Weimann, Steffen; Keil, Robert; Miroshnichenko, Andrey E; Nolte, Stefan; Sukhorukov, Andrey A; Szameit, Alexander; Kivshar, Yuri S

    2013-01-01

    We describe theoretically and observe experimentally the formation of a surface state in a semi-infnite waveguide array with side-coupled waveguide, designed to simultaneously achieve Fano and Fabry-Perot resonances. We demonstrate that the surface mode is compact, with all energy concentrated in few waveguides at the edge and no field penetration beyond the side-coupled waveguide position. Furthermore, we show that by broadening the spectral band in the rest of the waveguide array it is possible to suppress exponentially localized modes, whereas the Fano state having the eigenvalue embedded in the continuum is preserved.

  7. Cherenkov and Fano effects at the origin of asymmetric vector mesons in nuclear media

    CERN Document Server

    Dremin, I M

    2015-01-01

    It is argued that the experimentally observed phenomenon of asymmetric vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Cherenkov and Fano effects. The mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape in the low-mass wing of the resonance. That is explained by the positive real part of the amplitude in this wing for classic Cherenkov treatment and further detalized in quantum mechanics as the interference of direct and continuum states in Fano effect. The corresponding parameters are found from the comparison with rho-meson data and admit reasonable explanation.

  8. Coherent Perfect Absorption induced by the nonlinearity of a Helmholtz resonator

    CERN Document Server

    Achilleos, V; Theocharis, G

    2016-01-01

    In this work, we analytically report Coherent Perfect Absorption induced by the acoustic nonlinear response of a Helmholtz Resonator side loaded to a waveguide. In particular, we show that this two-port acoustic system can perfectly absorb two high amplitude symmetric incident waves when the additive nonlinear losses in the HR, induced by the jet flow separation, together with the weak linear viscothermal losses of the HR balance the radiation losses to the waveguide. For the case of the one-sided incidence configuration, this condition leads to an absorption equal to 0.5. This result, which is verified experimentally, is in a good agreement with an analytical nonlinear model of the impedance of the HR. The nonlinear control of perfect absorption using resonators will open new possibilities in the design of high amplitude sound attenuators for aero-engine applications.

  9. Second-Order Nonlinearity in Triangular Lattice Perforated Gold Film due to Surface Plasmas Resonance

    Directory of Open Access Journals (Sweden)

    Renlong Zhou

    2014-01-01

    Full Text Available We have studied the excitation second-order nonlinearity through a triangular lattice perforated gold film instead of square lattice in many papers. Under the excitation of surface plasmas resonance effect, the second order nonlinearity exists in the noncentrosymmetric split-ring resonators arrays. Reflection of fundamental frequency wave through a triangular lattice perforated gold film is obtained. We also described the second harmonic conversion efficiencies in the second order nonlinear optical process with the spectra. Moreover, the electric field distributions of fundamental frequency above the gold film region are calculated. The light propagation through the holes results in the enhancement of the second order nonlinearity including second harmonic generation as well as the sum (difference frequency generation.

  10. Nonlinear dynamics of nanomechanical beam resonators: improving the performance of NEMS-based sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kacem, N; Hentz, S; Pinto, D; Reig, B; Nguyen, V [CEA/LETI-MINATEC, Grenoble (France)

    2009-07-08

    In order to compensate for the loss of performance when scaling resonant sensors down to NEMS, it proves extremely useful to study the behavior of resonators up to very high displacements and hence high nonlinearities. This work describes a comprehensive nonlinear multiphysics model based on the Euler-Bernoulli equation which includes both mechanical and electrostatic nonlinearities valid up to displacements comparable to the gap in the case of an electrostatically actuated doubly clamped beam. Moreover, the model takes into account the fringing field effects, significant for thin resonators. The model has been compared to both numerical integrations and electrical measurements of devices fabricated on 200 mm SOI wafers; it shows very good agreement with both. An important contribution of this work is the provision for closed-form expressions of the critical amplitude and the pull-in domain initiation amplitude including all nonlinearities. This model allows designers to cancel out nonlinearities by tuning some design parameters and thus gives the possibility to drive the resonator beyond its critical amplitude. Consequently, the sensor performance can be enhanced to the maximum below the pull-in instability, while keeping a linear behavior.

  11. Nonlinear dynamics of nanomechanical beam resonators: improving the performance of NEMS-based sensors.

    Science.gov (United States)

    Kacem, N; Hentz, S; Pinto, D; Reig, B; Nguyen, V

    2009-07-08

    In order to compensate for the loss of performance when scaling resonant sensors down to NEMS, it proves extremely useful to study the behavior of resonators up to very high displacements and hence high nonlinearities. This work describes a comprehensive nonlinear multiphysics model based on the Euler-Bernoulli equation which includes both mechanical and electrostatic nonlinearities valid up to displacements comparable to the gap in the case of an electrostatically actuated doubly clamped beam. Moreover, the model takes into account the fringing field effects, significant for thin resonators. The model has been compared to both numerical integrations and electrical measurements of devices fabricated on 200 mm SOI wafers; it shows very good agreement with both. An important contribution of this work is the provision for closed-form expressions of the critical amplitude and the pull-in domain initiation amplitude including all nonlinearities. This model allows designers to cancel out nonlinearities by tuning some design parameters and thus gives the possibility to drive the resonator beyond its critical amplitude. Consequently, the sensor performance can be enhanced to the maximum below the pull-in instability, while keeping a linear behavior.

  12. NONLINEAR DYNAMICS OF LATERAL MICRO-RESONATOR INCLUDING VISCOUS AIR DAMPING

    Institute of Scientific and Technical Information of China (English)

    GAO Rong; WANG Xiaojing; WANG Min; YU Maohua; XIE Mingchun

    2007-01-01

    The nonlinear dynamics of the lateral micro-resonator including the air damping effect is researched. The air damping force is varied periodically during the resonator oscillating, and the air damp coefficient can not be fixed as a constant. Therefore the linear dynamic analysis which used the constant air damping coefficient can not describe the actual dynamic characteristics of the micro-resonator. The nonlinear dynamic model including the air damping force is established. On the base of Navier-Stokes equation and nonlinear dynamical equation, a coupled fluid-solid numerical simulation method is developed and demonstrates that damping force is a vital factor in micro-comb structures. Compared with existing experimental result, the nonlinear numerical value has quite good agreement with it. The differences of the amplitudes (peak) between the experimental data and the results by the linear model and the nonlinear model are 74.5% and 6% respectively. Nonlinear numerical value is more exact than linear value and the method can be applied in other micro-electro-mechanical systeme (MEMS) structures to simulate the dynamic performance.

  13. Dynamics of nonlinear resonant slow MHD waves in twisted flux tubes

    Directory of Open Access Journals (Sweden)

    R. Erdélyi

    2002-01-01

    Full Text Available Nonlinear resonant magnetohydrodynamic (MHD waves are studied in weakly dissipative isotropic plasmas in cylindrical geometry. This geometry is suitable and is needed when one intends to study resonant MHD waves in magnetic flux tubes (e.g. for sunspots, coronal loops, solar plumes, solar wind, the magnetosphere, etc. The resonant behaviour of slow MHD waves is confined in a narrow dissipative layer. Using the method of simplified matched asymptotic expansions inside and outside of the narrow dissipative layer, we generalise the so-called connection formulae obtained in linear MHD for the Eulerian perturbation of the total pressure and for the normal component of the velocity. These connection formulae for resonant MHD waves across the dissipative layer play a similar role as the well-known Rankine-Hugoniot relations connecting solutions at both sides of MHD shock waves. The key results are the nonlinear connection formulae found in dissipative cylindrical MHD which are an important extension of their counterparts obtained in linear ideal MHD (Sakurai et al., 1991, linear dissipative MHD (Goossens et al., 1995; Erdélyi, 1997 and in nonlinear dissipative MHD derived in slab geometry (Ruderman et al., 1997. These generalised connection formulae enable us to connect solutions obtained at both sides of the dissipative layer without solving the MHD equations in the dissipative layer possibly saving a considerable amount of CPU-time when solving the full nonlinear resonant MHD problem.

  14. Global stabilization of high-energy resonance for a nonlinear wideband electromagnetic vibration energy harvester

    Science.gov (United States)

    Masuda, Arata; Sato, Takeru

    2016-04-01

    This paper presents an experimental verification of a wideband nonlinear vibration energy harvester which has a globally stabilized high-energy resonating response. For the conventional linear vibration energy harvester, the maximum performance of the power generation and its bandwidth are in a relation of trade-off. The resonance frequency band can be expanded by introducing a Duffing-type nonlinear resonator in order to enable the harvester to generate larger electric power in a wider frequency range. However, since such nonlinear resonators often have multiple stable steady-state solutions in the resonance band, it is difficult for the nonlinear harvester to maintain the high performance of the power generation constantly. The principle of self-excitation and entrainment has been utilized to provide the global stability to the highest-energy solution by destabilizing other unexpected lower-energy solutions by introducing a switching circuit of the load resistance between positive and the negative values depending on the response amplitude of the oscillator. In this study, an experimental verification of this concept are carried out. An experimental prototype harvester is designed and fabricated and the performance of the proposed harvester is experimentally verified. It has been shown that the numerical and experimental results agreed very well, and the highest-energy solutions above the threshold value were successfully stabilized globally.

  15. Spectroscopy of laser-induced autoionizing nonlinear resonances in atomic systems

    Science.gov (United States)

    Pavlov, L. I.; Kovachev, V. V.

    2015-03-01

    Efficient harmonic generation at laser-induced autoionizing state in continuum, were observed for the first time by our laboratory [1,2,3]. In this paper, nonlinear frequency mixing in alkali metal vapors at induced continuum structure in Na, are studied in detail. Besides, measurement of nonlinear optical susceptibility at induced autoionizing resonance, is performed. Tunable ultraviolet radiations by four-photon processes near induced resonances are obtained. Estimations of the real and imaginary parts of the nonlinearities, are estimated. We will specially note, that the resonant photoabsorption of ions is experimentally investigated since it gives information about the autoionizing states, which is impossible to obtain on the base only of the emission spectra. We use also laser inducing for obtaining of powerful radiation source in VUV. Thus, many actual problems as the selective impact on matter, laser photochemistry and laser isotope separation are connected directly with the induced autoionizing nonlinear resonances. The main interest is to control the spectral characteristics of continuum. The discrete level from the continuum structure leads to appearance of asymmetrical autoionizing resonance onto the background of the broad-band absorption line.

  16. Nonlinear damping in mechanical resonators made from carbon nanotubes and graphene

    Science.gov (United States)

    Eichler, A.; Moser, J.; Chaste, J.; Zdrojek, M.; Wilson-Rae, I.; Bachtold, A.

    2011-06-01

    The theory of damping is discussed in Newton's Principia and has been tested in objects as diverse as the Foucault pendulum, the mirrors in gravitational-wave detectors and submicrometre mechanical resonators. In general, the damping observed in these systems can be described by a linear damping force. Advances in nanofabrication mean that it is now possible to explore damping in systems with one or more atomic-scale dimensions. Here we study the damping of mechanical resonators based on carbon nanotubes and graphene sheets. The damping is found to strongly depend on the amplitude of motion, and can be described by a nonlinear rather than a linear damping force. We exploit the nonlinear nature of damping in these systems to improve the figures of merit for both nanotube and graphene resonators. For instance, we achieve a quality factor of 100,000 for a graphene resonator.

  17. Balanced line bundles on Fano varieties

    DEFF Research Database (Denmark)

    Lehmann, Brian; Tanimoto, Sho; Tschinkel, Yuri

    2017-01-01

    A conjecture of Batyrev and Manin relates arithmetic properties of varieties with ample anticanonical class to geometric invariants. We analyze the geometry underlying these invariants using the Minimal Model Program and then apply our results to primitive Fano threefolds....

  18. Frequency map analysis of resonances in a nonlinear lattice with space charge

    Energy Technology Data Exchange (ETDEWEB)

    Turchetti, G. E-mail: turchetti@bo.infn.it; Bazzani, A.; Bergamini, F.; Rambaldi, S.; Hofmann, I.; Bongini, L.; Franchetti, G

    2001-05-21

    In storage rings for heavy ion fusion beam losses must be minimized. During bunch compression high space charge is reached and the reciprocal effects between the collective modes of the beam and the single particle lattice nonlinearities must be considered to understand the problem of resonance crossing and halo formation. We show that the frequency map analysis of particle in core models gives an adequate description of the resonance network and of the chaotic regions where the halo particles can diffuse.

  19. Microcavity with saturable nonlinearity under simultaneous resonant and nonresonant pumping: multistability, Hopf bifurcations and chaotic behaviour.

    Science.gov (United States)

    Iorsh, Ivan; Alodjants, Alexander; Shelykh, Ivan A

    2016-05-30

    We studied optical response of microcavity non-equilibrium exciton-polariton Bose-Einstein condensate with saturable nonlinearity under simultaneous resonant and non-resonant pumping. We demonstrated the emergence of multistabile behavior due to the saturation of the excitonic absorption. Stable periodic Rabi-type oscillations of the excitonic and photonic condensate components in the regime of the stationary pump and their transition to the chaotic dynamics through the cascade of Hopf bifurcations by tuning of the electrical pump are revealed.

  20. Enhanced all-optical switching by use of a nonlinear fiber ring resonator.

    Science.gov (United States)

    Heebner, J E; Boyd, R W

    1999-06-15

    We predict dramatically reduced switching thresholds for nonlinear optical devices incorporating fiber ring resonators. The circulating power in such a resonator is much larger than the incident power; also, the phase of the transmitted light varies rapidly with the single-pass phase shift. The combined action of these effects leads to a finesse-squared reduction in the switching threshold, allowing for photonic switching devices that operate at milliwatt power levels in ordinary optical fibers.

  1. Microcavity with saturable nonlinearity under simultaneous resonant and nonresonant pumping: multistability, Hopf bifurcations and chaotic behaviour

    CERN Document Server

    Iorsh, Ivan; Shelykh, Ivan

    2016-01-01

    We studied optical response of microcavity non-equilibrium exciton-polariton Bose-Einstein condensate with saturable nonlinearity under simultaneous resonant and non-resonant pumping. We demonstrated the emergence of multistabile behavior due to the satutration of the excitonic absorbtion. Stable periodic Rabi- type oscillations of the excitonic and photonic condensate components in the regime of the stationary pump and their transition to the chaotic dynamics through the cascade of Hopf bifurcations by tuning of the electrical pump are revealed.

  2. Generating giant and tunable nonlinearity in a macroscopic mechanical resonator from a single chemical bond

    Science.gov (United States)

    Huang, Pu; Zhou, Jingwei; Zhang, Liang; Hou, Dong; Lin, Shaochun; Deng, Wen; Meng, Chao; Duan, Changkui; Ju, Chenyong; Zheng, Xiao; Xue, Fei; Du, Jiangfeng

    2016-05-01

    Nonlinearity in macroscopic mechanical systems may lead to abundant phenomena for fundamental studies and potential applications. However, it is difficult to generate nonlinearity due to the fact that macroscopic mechanical systems follow Hooke's law and respond linearly to external force, unless strong drive is used. Here we propose and experimentally realize high cubic nonlinear response in a macroscopic mechanical system by exploring the anharmonicity in chemical bonding interactions. We demonstrate the high tunability of nonlinear response by precisely controlling the chemical bonding interaction, and realize, at the single-bond limit, a cubic elastic constant of 1 × 1020 N m-3. This enables us to observe the resonator's vibrational bi-states transitions driven by the weak Brownian thermal noise at 6 K. This method can be flexibly applied to a variety of mechanical systems to improve nonlinear responses, and can be used, with further improvements, to explore macroscopic quantum mechanics.

  3. Unified model and reverse recovery nonlinearities of the driven diode resonator.

    Science.gov (United States)

    de Moraes, Renato Mariz; Anlage, Steven M

    2003-08-01

    We study the origins of period doubling and chaos in the driven series resistor-inductor-varactor diode (RLD) nonlinear resonant circuit. We find that resonators driven at frequencies much higher than the diode reverse recovery rate do not show period doubling. Models of chaos based on the nonlinear capacitance of the varactor diode display a reverse-recovery-like effect, and this effect strongly resembles reverse recovery of real diodes. We find for the first time that in addition to the known dependence of the reverse recovery time on past current maxima, there are also important nonlinear dependencies on pulse frequency, duty cycle, and dc voltage bias. Similar nonlinearities are present in the nonlinear capacitance models of these diodes. We conclude that a history-dependent and nonlinear reverse-recovery time is an essential ingredient for chaotic behavior of this circuit, and demonstrate for the first time that all major competing models have this effect, either explicitly or implicitly. Besides unifying the two major models of RLD chaos, our work reveals that the nonlinearities of the reverse-recovery time must be included for a complete understanding of period doubling and chaos in this circuit.

  4. Analysis of Nonlinear Structural Dynamics and Resonance in Trees

    Directory of Open Access Journals (Sweden)

    H. Doumiri Ganji

    2012-01-01

    Full Text Available Wind and gravity both impact trees in storms, but wind loads greatly exceed gravity loads in most situations. Complex behavior of trees in windstorms is gradually turning into a controversial concern among ecological engineers. To better understand the effects of nonlinear behavior of trees, the dynamic forces on tree structures during periods of high winds have been examined as a mass-spring system. In fact, the simulated dynamic forces created by strong winds are studied in order to determine the responses of the trees to such dynamic loads. Many of such nonlinear differential equations are complicated to solve. Therefore, this paper focuses on an accurate and simple solution, Differential Transformation Method (DTM, to solve the derived equation. In this regard, the concept of differential transformation is briefly introduced. The approximate solution to this equation is calculated in the form of a series with easily computable terms. Then, the method has been employed to achieve an acceptable solution to the presented nonlinear differential equation. To verify the accuracy of the proposed method, the obtained results from DTM are compared with those from the numerical solution. The results reveal that this method gives successive approximations of high accuracy solution.

  5. Nonlinear resonances in a multi-stage free-electron laser amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, S. [Graduate Univ. for Advanced Studies, Ibaraki-ken (Japan); Takayama, K. [National Lab. for High Energy Physics, Ibaraki-ken (Japan)

    1995-12-31

    A two-beam accelerator (TBA) is a possible candidate of future linear colliders, in which the demanded rf power is provided by a multi-stage free-electron laser (MFEL). After if amplification in each stage, a driving beam is re-accelerated by an induction unit and propagates into the next stage. Recently it has been recognized that the multi-stage character of the MFEL causes resonances between its periodicity and the synchrotron motion in an rf bucket. Since the synchrotron oscillation is strongly modulated by the resonance and at the worst a large fraction of particles is trapped in the resonance islands, the nonlinear resonances in the FEL longitudinal beam dynamics can lead to notable degradation of the MFEL performance, such as output fluctuation and phase modulation which have been big concerns in the accelerator society. The overall efficiency of the MFEL and the quality of the amplified microwave power are key issues for realizing the TBA/FEL Particularly the rf phase and amplitude errors must be maintained within tolerance. One of significant obstacles is an amplification of undesired modes. If a small-size waveguide is employed, the FEL resonance energies for undesired higher order modes shift very far from that for a fundamental mode; so it is possible to prevent higher order modes from evolving. Such a small-size waveguide, however, gives a high power density in the FEL. Simulation results have demonstrated that the nonlinear resonances occur in die FEL longitudinal motion when the power density exceeds some threshold. An analytical method for studying the nonlinear resonance in the TBA/FEL is developed based on the macroparticle model which can describe analytically the drastic behaviors in the evolutions of the phase and amplitude. In the theory the basic 1D-FEL equations are reduced to a nonlinear pendulum equation with respect to the ponderomotive phase.

  6. A relation between electromagnetically induced absorption resonances and nonlinear magneto-optics in Lambda-systems

    CERN Document Server

    Budker, D

    2003-01-01

    Recent work on Lambda-resonances in alkali metal vapors (E. Mikhailov, I. Novikova, Yu. V. Rostovtsev, and G. R. Welch, quant-ph/0309171, and references therein) has revealed a novel type of electromagnetically induced absorption resonance that occurs in three-level systems under specific conditions normally associated with electromagnetically induced transparency. In this note, we show that these resonances have a direct analog in nonlinear magneto-optics, and support this conclusion with a calculation for a J=1->J'=0 system interacting with a single nearly circularly polarized light field in the presence of a weak longitudinal magnetic field.

  7. Measurement of nonlinear elastic response in rock by the resonant bar method

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, P.A. (Los Alamos National Lab., NM (United States)); Rasolofosaon, P.; Zinszner, B. (Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France))

    1993-01-01

    In this work we are studying the behavior of the fundamental (Young's) mode resonant peak as a function of drive amplitude in rock samples. Our goal from these studies is to obtain nonlinear moduli for many rock types, and to study the nonlinear moduli as a function of water saturation and other changes in physical properties. Measurements were made on seven different room dry rock samples. For one sample measurements were taken at 16 saturation levels between 1 and 98%. All samples display a softening'' nonlinearity, that is, the resonant frequency shifts downward with increasing drive amplitude. In extreme cases, the resonant frequency changes by as much as 25% over a strain interval of 10[sup [minus]7] to [approximately]4 [times] 10[sup [minus]5]. Measurements indicate that the nonlinear response is extremely sensitive to saturation. Estimates of a combined cubic and quartic nonlinear parameter [Gamma] range from approximately [minus]300 to [minus]10[sup 9] for the rock samples.

  8. Nonlinear resonant absorption of fast magnetoacoustic waves in strongly anisotropic and dispersive plasmas

    CERN Document Server

    Clack, C

    2009-01-01

    The nonlinear theory of driven magnetohydrodynamics (MHD) waves in strongly anisotropic and dispersive plasmas, developed for slow resonance by Clack and Ballai [Phys. Plasmas, 15, 2310 (2008)] and Alfv\\'en resonance by Clack \\emph{et al.} [A&A,494, 317 (2009)], is used to study the weakly nonlinear interaction of fast magnetoacoustic (FMA) waves in a one-dimensional planar plasma. The magnetic configuration consists of an inhomogeneous magnetic slab sandwiched between two regions of semi-infinite homogeneous magnetic plasmas. Laterally driven FMA waves penetrate the inhomogeneous slab interacting with the localized slow or Alfv\\'{e}n dissipative layer and are partly reflected, dissipated and transmitted by this region. The nonlinearity parameter defined by Clack and Ballai (2008) is assumed to be small and a regular perturbation method is used to obtain analytical solutions in the slow dissipative layer. The effect of dispersion in the slow dissipative layer is to further decrease the coefficient of ener...

  9. Design of an efficient terahertz source using triply resonant nonlinear photonic crystal cavities.

    Science.gov (United States)

    Burgess, Ian B; Zhang, Yinan; McCutcheon, Murray W; Rodriguez, Alejandro W; Bravo-Abad, Jorge; Johnson, Steven G; Loncar, Marko

    2009-10-26

    We propose a scheme for efficient cavity-enhanced nonlinear THz generation via difference-frequency generation (DFG) processes using a triply resonant system based on photonic crystal cavities. We show that high nonlinear overlap can be achieved by coupling a THz cavity to a doubly-resonant, dual-polarization near-infrared (e.g. telecom band) photonic-crystal nanobeam cavity, allowing the mixing of three mutually orthogonal fundamental cavity modes through a chi((2)) nonlinearity. We demonstrate through coupled-mode theory that complete depletion of the pump frequency - i.e., quantum-limited conversion - is possible. We show that the output power at the point of optimal total conversion efficiency is adjustable by varying the mode quality (Q) factors.

  10. Weak-periodic stochastic resonance in a parallel array of static nonlinearities.

    Directory of Open Access Journals (Sweden)

    Yumei Ma

    Full Text Available This paper studies the output-input signal-to-noise ratio (SNR gain of an uncoupled parallel array of static, yet arbitrary, nonlinear elements for transmitting a weak periodic signal in additive white noise. In the small-signal limit, an explicit expression for the SNR gain is derived. It serves to prove that the SNR gain is always a monotonically increasing function of the array size for any given nonlinearity and noisy environment. It also determines the SNR gain maximized by the locally optimal nonlinearity as the upper bound of the SNR gain achieved by an array of static nonlinear elements. With locally optimal nonlinearity, it is demonstrated that stochastic resonance cannot occur, i.e. adding internal noise into the array never improves the SNR gain. However, in an array of suboptimal but easily implemented threshold nonlinearities, we show the feasibility of situations where stochastic resonance occurs, and also the possibility of the SNR gain exceeding unity for a wide range of input noise distributions.

  11. Self-induced parametric amplification arising from nonlinear elastic coupling in a micromechanical resonating disk gyroscope.

    Science.gov (United States)

    Nitzan, Sarah H; Zega, Valentina; Li, Mo; Ahn, Chae H; Corigliano, Alberto; Kenny, Thomas W; Horsley, David A

    2015-01-01

    Parametric amplification, resulting from intentionally varying a parameter in a resonator at twice its resonant frequency, has been successfully employed to increase the sensitivity of many micro- and nano-scale sensors. Here, we introduce the concept of self-induced parametric amplification, which arises naturally from nonlinear elastic coupling between the degenerate vibration modes in a micromechanical disk-resonator, and is not externally applied. The device functions as a gyroscope wherein angular rotation is detected from Coriolis coupling of elastic vibration energy from a driven vibration mode into a second degenerate sensing mode. While nonlinear elasticity in silicon resonators is extremely weak, in this high quality-factor device, ppm-level nonlinear elastic effects result in an order-of-magnitude increase in the observed sensitivity to Coriolis force relative to linear theory. Perfect degeneracy of the primary and secondary vibration modes is achieved through electrostatic frequency tuning, which also enables the phase and frequency of the parametric coupling to be varied, and we show that the resulting phase and frequency dependence of the amplification follow the theory of parametric resonance. We expect that this phenomenon will be useful for both fundamental studies of dynamic systems with low dissipation and for increasing signal-to-noise ratio in practical applications such as gyroscopes.

  12. Symmetry Breaking of Counter-Propagating Light in a Nonlinear Resonator

    Science.gov (United States)

    Del Bino, Leonardo; Silver, Jonathan M.; Stebbings, Sarah L.; Del'Haye, Pascal

    2017-01-01

    Spontaneous symmetry breaking is a concept of fundamental importance in many areas of physics, underpinning such diverse phenomena as ferromagnetism, superconductivity, superfluidity and the Higgs mechanism. Here we demonstrate nonreciprocity and spontaneous symmetry breaking between counter-propagating light in dielectric microresonators. The symmetry breaking corresponds to a resonance frequency splitting that allows only one of two counter-propagating (but otherwise identical) states of light to circulate in the resonator. Equivalently, this effect can be seen as the collapse of standing waves and transition to travelling waves within the resonator. We present theoretical calculations to show that the symmetry breaking is induced by Kerr-nonlinearity-mediated interaction between the counter-propagating light. Our findings pave the way for a variety of applications including optically controllable circulators and isolators, all-optical switching, nonlinear-enhanced rotation sensing, optical flip-flops for photonic memories as well as exceptionally sensitive power and refractive index sensors. PMID:28220865

  13. Non-Linear High Amplitude Oscillations in Wave-shaped Resonators

    Science.gov (United States)

    Antao, Dion; Farouk, Bakhtier

    2011-11-01

    A numerical and experimental study of non-linear, high amplitude standing waves in ``wave-shaped'' resonators is reported here. These waves are shock-less and can generate peak acoustic overpressures that can exceed the ambient pressure by three/four times its nominal value. A high fidelity compressible axisymmetric computational fluid dynamic model is used to simulate the phenomena in cylindrical and arbitrarily shaped axisymmetric resonators. Working fluids (Helium, Nitrogen and R-134a) at various operating pressures are studied. The experiments are performed in a constant cross-section cylindrical resonator in atmospheric pressure nitrogen and helium to provide model validation. The high amplitude non-linear oscillations demonstrated can be used as a prime mover in a variety of applications including thermoacoustic cryocooling. The work reported is supported by the US National Science Foundation under grant CBET-0853959.

  14. Analysis of internal resonance in a two-degree-of-freedom nonlinear dynamical system

    Science.gov (United States)

    Dai, Honghua; Wang, Xuechuan; Schnoor, Matt; Atluri, Satya N.

    2017-08-01

    This study is devoted to the analysis of the three-to-one internal resonance in a two degree-of-freedom system with cubic nonlinearity. Quasi-periodic motion is found to appear in the present system with internal resonance, while it does not show up in the case without internal resonance. Both the time domain collocation method and the harmonic balance method are applied to obtain the periodic solutions, and are compared with the benchmark solution of the numerical integration method. In contrast, the quasi-periodic solutions can only be captured via the numerical integration method. A combination of the phase plane portrait, Poincare map, and the frequency spectrum are employed to identify the quasi-periodic motions. A peculiar bifurcation-of-attraction-basin phenomenon is found and demonstrated. Moreover, for strongly nonlinear system subject to high external force, a long-lived chaotic transient is observed.

  15. Coupling between Fano and Bragg bands in photonic band structure of two-dimensional metallic photonic structures

    CERN Document Server

    Markos, Peter

    2016-01-01

    Frequency and transmission spectrum of two-dimensional array of metallic rods is investigated numerically. Based on the recent analysis of the band structure of two-dimensional photonic crystal with dielectric rods [P. Marko\\v{s}, Phys. Rev. A 92 043814 (2015)] we identify two types of bands in the frequency spectrum: Bragg (P) bands resulting from a periodicity and Fano (F) bands which arise from Fano resonances associated with each of the cylinders within the periodic structure. It is shown that the existence of Fano band in a certain frequency range is manifested by a Fano resonance in the transmittance. In particular, we re-examine the symmetry properties of the H- polarized band structure in the frequency range where the spectrum consists of the localized modes associated with the single scatterer resonances and we explore process of formation of Fano bands by identifying individual terms in the expansion of the LCAO states. We demonstrate how the interplay between the two scattering mechanisms affects p...

  16. Strongly driven nonlinear quantum optics in microring resonators

    CERN Document Server

    Vernon, Z

    2015-01-01

    We present a detailed analysis of strongly driven spontaneous four-wave mixing in a lossy integrated microring resonator side-coupled to a channel waveguide. A nonperturbative, analytic solution within the undepleted pump approximation is developed for a cw pump input of arbitrary intensity. In the strongly driven regime self- and cross-phase modulation, as well as multi-pair generation, lead to a rich variety of power-dependent effects; the results are markedly different than in the low power limit. The photon pair generation rate, single photon spectrum, and joint spectral intensity (JSI) distribution are calculated. Splitting of the generated single photon spectrum into a doublet structure associated with both pump detuning and cross-phase modulation is predicted, as well as substantial narrowing of the generated signal and idler bandwidths associated with the onset of optical parametric oscillation at intermediate powers. Both the correlated and uncorrelated contributions to the JSI are calculated, and fo...

  17. Wavenumber resonance in nonlinear wave interactions in the wake of a flat plate

    Science.gov (United States)

    Davila, Jose Benigno

    The spatial traits of nonlinear wave interactions in transitioning flow in the symmetric wake of a flat plate were studied. The study combines the use of hot wire anemometry and digital analysis techniques for extracting frequency and wavenumber information from velocity fluctuation time series measurements. The linear spatial coherence was computed from velocity fluctuation data in order to determine if the frequency modes behave as waves, that is, spatially coherent fluctuations with a well defined dispersion relation. A new method was used to compute the mode triad wavenumber mismatch. The results were used to determine to what extent wavenumber resonance is present among quadratically interacting frequency resonant modes, as predicted by resonant wave interaction theory. The results show that, in the early part of the transition, instability modes interact nonlinearity to generate spatially coherent modes at frequencies above the instability range. Quadratically interacting, frequency resonant mode triads involve the transfer of energy to the harmonics of the fundamental instability exhibit good wavenumber resonance, as predicted by resonant wave interaction theory.

  18. Nonlinear mode coupling and internal resonances in MoS2 nanoelectromechanical system

    Science.gov (United States)

    Samanta, C.; Yasasvi Gangavarapu, P. R.; Naik, A. K.

    2015-10-01

    Atomically thin two dimensional (2D) layered materials have emerged as a new class of material for nanoelectromechanical systems (NEMS) due to their extraordinary mechanical properties and ultralow mass density. Among them, graphene has been the material of choice for nanomechanical resonator. However, recent interest in 2D chalcogenide compounds has also spurred research in using materials such as MoS2 for the NEMS applications. As the dimensions of devices fabricated using these materials shrink down to atomically thin membrane, strain and nonlinear effects have become important. A clear understanding of the nonlinear effects and the ability to manipulate them is essential for next generation sensors. Here, we report on all electrical actuation and detection of few-layer MoS2 resonator. The ability to electrically detect multiple modes and actuate the modes deep into the nonlinear regime enables us to probe the nonlinear coupling between various vibrational modes. The modal coupling in our device is strong enough to detect three distinct internal resonances.

  19. A Weakly Nonlinear Model for the Damping of Resonantly Forced Density Waves in Dense Planetary Rings

    Science.gov (United States)

    Lehmann, Marius; Schmidt, Jürgen; Salo, Heikki

    2016-10-01

    In this paper, we address the stability of resonantly forced density waves in dense planetary rings. Goldreich & Tremaine have already argued that density waves might be unstable, depending on the relationship between the ring’s viscosity and the surface mass density. In the recent paper Schmidt et al., we have pointed out that when—within a fluid description of the ring dynamics—the criterion for viscous overstability is satisfied, forced spiral density waves become unstable as well. In this case, linear theory fails to describe the damping, but nonlinearity of the underlying equations guarantees a finite amplitude and eventually a damping of the wave. We apply the multiple scale formalism to derive a weakly nonlinear damping relation from a hydrodynamical model. This relation describes the resonant excitation and nonlinear viscous damping of spiral density waves in a vertically integrated fluid disk with density dependent transport coefficients. The model consistently predicts density waves to be (linearly) unstable in a ring region where the conditions for viscous overstability are met. Sufficiently far away from the Lindblad resonance, the surface mass density perturbation is predicted to saturate to a constant value due to nonlinear viscous damping. The wave’s damping lengths of the model depend on certain input parameters, such as the distance to the threshold for viscous overstability in parameter space and the ground state surface mass density.

  20. Smooth Fano polytopes can not be inductively constructed

    DEFF Research Database (Denmark)

    Øbro, Mikkel

    2008-01-01

    We examine a concrete smooth Fano 5-polytope $P$ with 8 vertices with the following properties: There does not exist a smooth Fano 5-polytope $Q$ with 7 vertices such that $P$ contains $Q$, and there does not exist a smooth Fano 5-polytope $R$ with 9 vertices such that $R$ contains $P$. As the po...

  1. Parametric study on nonlinear vibration of composite truss core sandwich plate with internal resonance

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jia Nen; Liu, Jun [Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System, Tianjin University of Technology, Tianjin (China); Zhang, Wei; Yao, Ming Hui [College of Mechanical Engineering, Beijing University of Technology, Beijing (China); Sun, Min [School of Science, Tianjin Chengjian University, Tianjin (China)

    2016-09-15

    Nonlinear vibrations of carbon fiber reinforced composite sandwich plate with pyramidal truss core are investigated. The governing equation of motion for the sandwich plate is derived by using a Zig-Zag theory under consideration of geometrically nonlinear. The natural frequencies of sandwich plates with different dimensions are calculated and compared with those obtained from the classic laminated plate theory and Reddy's third-order shear deformation plate theory. The frequency responses and waveforms of the sandwich plate when 1:3 internal resonance occurs are obtained, and the characteristics of the internal resonance are discussed. The influences of layer number of face sheet, strut radius, core height and inclination angle on the nonlinear responses of the sandwich plate are analyzed. The results demonstrate that the strut radius and inclination angle mainly affect the resonance frequency band of the sandwich plate, and the layer number and core height not only influence the resonance frequency band but also significantly affect the response amplitude.

  2. Nonlinear fundamental and harmonic cyclotron resonant scattering of radiation belt ultrarelativistic electrons by oblique monochromatic EMIC waves

    Science.gov (United States)

    Wang, Geng; Su, Zhenpeng; Zheng, Huinan; Wang, Yuming; Zhang, Min; Wang, Shui

    2017-02-01

    Cyclotron resonant scattering by electromagnetic ion cyclotron (EMIC) waves has been considered to be responsible for the rapid loss of radiation belt high-energy electrons. For parallel-propagating EMIC waves, the nonlinear character of cyclotron resonance has been revealed in recent studies. Here we present the first study on the nonlinear fundamental and harmonic cyclotron resonant scattering of radiation belt ultrarelativistic electrons by oblique EMIC waves on the basis of test particle simulations. Higher wave obliquity produces stronger nonlinearity of harmonic resonances but weaker nonlinearity of fundamental resonance. Compared to the quasi-linear prediction, these nonlinear resonances yield a more rapid loss of electrons over a wider pitch angle range. In the quasi-linear regime, the ultrarelativistic electrons are lost in the equatorial pitch angle range αeq87.5° at ψ = 20° and 40°. At the resonant pitch angles αeq<75°, the difference between quasi-linear and nonlinear loss timescales tends to decrease with the wave normal angle increasing. At ψ = 0° and 20°, the nonlinear electron loss timescale is 10% shorter than the quasi-linear prediction; at ψ = 40°, the difference in loss timescales is reduced to <5%.

  3. Bifurcation and Resonance of a Mathematical Model for Non-Linear Motion of a Flooded Ship in Waves

    Science.gov (United States)

    Murashige, S.; Aihara, K.; Komuro, M.

    1999-02-01

    A flooded ship can exhibit undesirable non-linear roll motion even in waves of moderate amplitude. In order to understand the mechanism of this non-linear phenomenon, the non-linearly coupled dynamics of a ship and flood water are considered using a mathematical model for the simplified motion of a flooded ship in regular beam waves. This paper describes bifurcation and resonance of this coupled system. A bifurcation diagram shows that large-amplitude subharmonic motion exists in a wide range of parameters, and that the Hopf bifurcation is observed due to the dynamic effects of flood water. Resonance frequencies can be determined by linearization of this model. Comparison between the resonant points and the bifurcation curves suggests that non-linear resonance of this model can bring about large-amplitude subharmonic motion, even if it is in the non-resonate state of the linearized system.

  4. Heteroclinic structure of parametric resonance in the nonlinear Schr\\"odinger equation

    CERN Document Server

    Conforti, M; Kudlinski, A; Rota-Nodari, S; Dujardin, G; De Bievre, S; Armaroli, A; Trillo, S

    2016-01-01

    We show that the nonlinear stage of modulational instability induced by parametric driving in the {\\em defocusing} nonlinear Schr\\"odinger equation can be accurately described by combining mode truncation and averaging methods, valid in the strong driving regime. The resulting integrable oscillator reveals a complex hidden heteroclinic structure of the instability. A remarkable consequence, validated by the numerical integration of the original model, is the existence of breather solutions separating different Fermi-Pasta-Ulam recurrent regimes. Our theory also shows that optimal parametric amplification unexpectedly occurs outside the bandwidth of the resonance (or Arnold tongues) arising from the linearised Floquet analysis.

  5. One dimensional resonant Fibonacci quasicrystals: noncanonical linear and canonical nonlinear effects.

    Science.gov (United States)

    Werchner, M; Schafer, M; Kira, M; Koch, S W; Sweet, J; Olitzky, J D; Hendrickson, J; Richards, B C; Khitrova, G; Gibbs, H M; Poddubny, A N; Ivchenko, E L; Voronov, M; Wegener, M

    2009-04-13

    A detailed experimental and theoretical study of the linear and nonlinear optical properties of different Fibonacci-spaced multiple-quantum-well structures is presented. Systematic numerical studies are performed for different average spacing and geometrical arrangement of the quantum wells. Measurements of the linear and nonlinear (carrier density dependent) reflectivity are shown to be in good agreement with the computational results. As the pump pulse energy increases, the excitation-induced dephasing broadens the exciton resonances resulting in a disappearance of sharp features and reduction in peak reflectivity.

  6. Nonlinear resonances in a class of multi-degree-of-freedom systems

    Science.gov (United States)

    Sridhar, S.; Nayfeh, A. H.; Mook, D. T.

    1975-01-01

    An analysis is presented of the superharmonic, subharmonic, and combination resonances in a multi-degree-of-freedom system which has cubic nonlinearity and modal viscous damping and is subject to harmonic excitation. It is shown that, in the absence of internal resonances, the steady-state response contains only the modes which are directly excited. It is shown that, in the presence of internal resonances, modes other than those that are directly excited can appear in the response. The strong influence of internal resonances is exhibited in numerical examples involving hinged-clamped beams. It is shown that when a multimode solution exists the lowest mode can dominate the response, even when it is not directly excited.

  7. Symmetry Breaking of Counter-Propagating Light in a Nonlinear Resonator

    CERN Document Server

    Del Bino, Leonardo; Stebbings, Sarah L; Del'Haye, Pascal

    2016-01-01

    Light is generally expected to travel through isotropic media independent of its direction. This makes it challenging to develop non-reciprocal optical elements like optical diodes or circulators, which currently rely on magneto-optical effects and birefringent materials. Here we present measurements of non-reciprocal transmission and spontaneous symmetry breaking between counter-propagating light in dielectric microresonators. The symmetry breaking corresponds to a resonance frequency splitting that allows only one of two counter-propagating (but otherwise identical) light waves to circulate in the resonator. Equivalently, the symmetry breaking can be seen as the collapse of standing waves and transition to travelling waves within the resonator. We present theoretical calculations to show that the symmetry breaking is induced by Kerr-nonlinearity-mediated interaction between the counter-propagating light. This effect is expected to take place in any dielectric ring-resonator and might constitute one of the m...

  8. Nonlinearities and noise in micromechanical resonators: From understanding to characterization and design tools

    Science.gov (United States)

    Polunin, Pavel M.

    In this work we consider several nonlinearity-based and/or noise-related phenomena that have been recently observed in micro-electromechanical vibratory systems. The main goals are to closely examine these phenomena, develop an understanding of their underlying physics, derive techniques for characterizing parameters in relevant mathematical models, and determine ways to improve the performance of specific classes of micro-electromechanical systems (MEMS) used in applications. The general perspective of this work is based on the fact that nonlinearity and noise represent integral parts of the models needed to describe the response of these systems, and the focus is on situations where these generally undesirable features can be utilized or accounted for in design. We consider three different, but related, topics in this general area. The first topic uses the slowly varying states in a rotating frame of reference where we analyze the stationary probability distribution of a nonlinear parametrically-driven resonator subjected to Poisson pulses and thermal noise. We show that Poisson pulses with low pulse rates, as compared with the resonator decay rate, cause a power-law divergence of the probability density at the resonator equilibrium in both the underdamped (overdamped) regimes, in which the response does (does not) spiral in the rotating frame. We have also found that the shape of the probability distribution away from the equilibrium position is qualitatively different for the overdamped and underdamped cases. In particular, in the overdamped regime, the form of the secondary singularity in the probability distribution depends strongly on the reference phase of the resonator response and the pulse modulation phase, while in the underdamped regime several singular peaks occur in the distribution, and their locations are determined by the resonator frequency and decay rate in the rotating frame. Finally, we show that even weak Gaussian noise smoothens out the

  9. Theory of Fano-Kondo effect in quantum dot systems: Temperature dependence of the Fano line shapes

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, I. [Physikalisches Institut der Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany)]. E-mail: maru@th.physik.uni-bonn.de; Shibata, N. [Department of Basic Science, University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902 (Japan); Ueda, K. [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8581 (Japan)

    2006-05-01

    The Fano-Kondo effect in zero-bias conductance is studied based on a theoretical model for the T-shaped quantum dot by the finite temperature density matrix renormalization group method. The modification of the two Fano line shapes at much higher temperatures than the Kondo temperature is also investigated by the effective Fano parameter estimated as a fitting parameter.

  10. Magnetic field amplification in nonlinear diffusive shock acceleration including resonant and non-resonant cosmic-ray driven instabilities

    CERN Document Server

    Bykov, Andrei M; Osipov, Sergei M; Vladimirov, Andrey E

    2014-01-01

    We present a nonlinear Monte Carlo model of efficient diffusive shock acceleration (DSA) where the magnetic turbulence responsible for particle diffusion is calculated self-consistently from the resonant cosmic-ray (CR) streaming instability, together with non-resonant short- and long-wavelength CR-current-driven instabilities. We include the backpressure from CRs interacting with the strongly amplified magnetic turbulence which decelerates and heats the super-alfvenic flow in the extended shock precursor. Uniquely, in our plane-parallel, steady-state, multi-scale model, the full range of particles, from thermal (~eV) injected at the viscous subshock, to the escape of the highest energy CRs (~PeV) from the shock precursor, are calculated consistently with the shock structure, precursor heating, magnetic field amplification (MFA), and scattering center drift relative to the background plasma. In addition, we show how the cascade of turbulence to shorter wavelengths influences the total shock compression, the d...

  11. Nonlinear Forced Vibration of a Viscoelastic Buckled Beam with 2 : 1 Internal Resonance

    Directory of Open Access Journals (Sweden)

    Liu-Yang Xiong

    2014-01-01

    Full Text Available Nonlinear dynamics of a viscoelastic buckled beam subjected to primary resonance in the presence of internal resonance is investigated for the first time. For appropriate choice of system parameters, the natural frequency of the second mode is approximately twice that of the first providing the condition for 2 : 1 internal resonance. The ordinary differential equations of the two mode shapes are established using the Galerkin method. The problem is replaced by two coupled second-order differential equations with quadratic and cubic nonlinearities. The multiple scales method is applied to derive the modulation-phase equations. Steady-state solutions of the system as well as their stability are examined. The frequency-amplitude curves exhibit the steady-state response in the directly excited and indirectly excited modes due to modal interaction. The double-jump, the saturation phenomenon, and the nonperiodic region phenomena are observed illustrating the influence of internal resonance. The validity range of the analytical approximations is assessed by comparing the analytical approximate results with a numerical solution by the Runge-Kutta method. The unstable regions in the internal resonance are explored via numerical simulations.

  12. A new model for nonlinear acoustic waves in a non-uniform lattice of Helmholtz resonators

    CERN Document Server

    Mercier, Jean-François

    2016-01-01

    Propagation of high amplitude acoustic pulses is studied in a 1D waveguide, connected to a lattice of Helmholtz resonators. An homogenized model has been proposed by Sugimoto (J. Fluid. Mech., 244 (1992)), taking into account both the nonlinear wave propagation and various mechanisms of dissipation. This model is extended to take into account two important features: resonators of different strengths and back-scattering effects. The new model is derived and is proved to satisfy an energy balance principle. A numerical method is developed and a better agreement between numerical and experimental results is obtained.

  13. Noise-induced transitions and resonant effects in nonlinear systems

    Science.gov (United States)

    Zaikin, Alexei

    2003-02-01

    Our every-day experience is connected with different acoustical noise or music. Usually noise plays the role of nuisance in any communication and destroys any order in a system. Similar optical effects are known: strong snowing or raining decreases quality of a vision. In contrast to these situations noisy stimuli can also play a positive constructive role, e.g. a driver can be more concentrated in a presence of quiet music. Transmission processes in neural systems are of especial interest from this point of view: excitation or information will be transmitted only in the case if a signal overcomes a threshold. Dr. Alexei Zaikin from the Potsdam University studies noise-induced phenomena in nonlinear systems from a theoretical point of view. Especially he is interested in the processes, in which noise influences the behaviour of a system twice: if the intensity of noise is over a threshold, it induces some regular structure that will be synchronized with the behaviour of neighbour elements. To obtain such a system with a threshold one needs one more noise source. Dr. Zaikin has analyzed further examples of such doubly stochastic effects and developed a concept of these new phenomena. These theoretical findings are important, because such processes can play a crucial role in neurophysics, technical communication devices and living sciences. Unsere alltägliche Erfahrung ist mit verschiedenen akustischen Einfluessen wie Lärm, aber auch Musik verbunden. Jeder weiss, wie Lärm stören kann und Kommunikation behindert oder gar unterbindet. Ähnliche optische Effekte sind bekannt: starkes Schneetreiben oder Regengüsse verschlechtern die Sicht und lassen uns Umrisse nur noch schemenhaft erkennen. Jedoch koennen ähnliche Stimuli auch sehr positive Auswirkungen haben: Autofahrer fahren bei leiser Musik konzentrierter -- die Behauptung von Schulkindern, nur bei dröhnenden Bässen die Mathehausaufgaben richtig rechnen zu können, ist allerdings nicht wissenschaftlich

  14. The nonlinear saturation of the non-resonant kinetically driven streaming instability

    CERN Document Server

    Gargate, L; Niemiec, J; Pohl, M; Bingham, R; Silva, L O

    2010-01-01

    A non-resonant instability for the amplification of the interstellar magnetic field in young Supernova Remnant (SNR) shocks was predicted by Bell (2004), and is thought to be relevant for the acceleration of cosmic ray (CR) particles. For this instability, the CRs streaming ahead of SNR shock fronts drive electromagnetic waves with wavelengths much shorter than the typical CR Larmor radius, by inducing a current parallel to the background magnetic field. We explore the nonlinear regime of the non-resonant mode using Particle-in-Cell (PIC) hybrid simulations, with kinetic ions and fluid electrons, and analyze the saturation mechanism for realistic CR and background plasma parameters. In the linear regime, the observed growth rates and wavelengths match the theoretical predictions; the nonlinear stage of the instability shows a strong reaction of both the background plasma and the CR particles, with the saturation level of the magnetic field varying with the CR parameters. The simulations with CR-to-background ...

  15. Non-equilibrium many-body effects in driven nonlinear resonator arrays

    CERN Document Server

    Grujic, T; Angelakis, D G; Jaksch, D

    2012-01-01

    We study the non-equilibrium behavior of optically driven dissipative coupled resonator arrays. Assuming each resonator is coupled with a two-level system via a Jaynes-Cummings interaction, we calculate the many-body steady state behavior of the system under coherent pumping and dissipation. We propose and analyze the many-body phases using experimentally accessible quantities such as the total excitation number, the emitted photon spectra and photon coherence functions for different parameter regimes. In parallel, we also compare and contrast the expected behavior of this system assuming the local nonlinearity in the cavities is generated by a generic Kerr effect rather than a Jaynes-Cummings interaction. We find that the behavior of the experimentally accessible observables produced by the two models differs for realistic regimes of interactions even when the corresponding nonlinearities are of similar strength. We analyze in detail the extra features available in the Jaynes-Cummings-Hubbard (JCH) model ori...

  16. Nonlinear dynamic behaviors of clamped laminated shallow shells with one-to-one internal resonance

    Science.gov (United States)

    Abe, Akira; Kobayashi, Yukinori; Yamada, Gen

    2007-07-01

    This paper investigates one-to-one internal resonance of laminated shallow shells with rigidly clamped edges. It is assumed that the natural frequencies ω2 and ω3 of two asymmetric (second and third) vibration modes have the relationship ω2≈ ω3. The displacements are expressed by using eigenvectors for linear vibration modes calculated by the Ritz method. Applying Galerkin's procedure to the equation of motion, nonlinear differential equations are derived. By considering the first vibration mode in addition to the two asymmetric vibration modes, quadratic nonlinear terms expressing the interaction between the asymmetric and the first modes appear in the differential equations. Shooting method is used to obtain the steady-state response when the driving frequency Ω is near ω2. The dynamic characteristics of the shells with the internal resonance are discussed.

  17. A frequency up-converting harvester based on internal resonance in 2-DOF nonlinear systems

    Science.gov (United States)

    Wu, Yipeng; Qiu, Jinhao; Ji, Hongli

    2016-11-01

    This paper reports the design and experimental testing of a novel frequency up- converting piezoelectric energy harvester. The harvester is firstly approximated as a 2-degree- of-freedom cubic nonlinear system instead of the general Duffing systems. A 1:3 internal resonance innovatively applied in the frequency up-conversion approach is thoroughly investigated. Finally, the theoretical dynamic model confirmed by the experimental results clearly shows the effect of the frequency up-conversion.

  18. Rabi oscillations of two-photon states in nonlinear optical resonators

    Science.gov (United States)

    Sherkunov, Y.; Whittaker, David M.; Fal'ko, Vladimir

    2016-02-01

    We demonstrate that four-wave mixing processes in high-quality nonlinear resonators can lead to Rabi-like oscillations in photon occupation numbers and second-order correlation functions, being a characteristic feature of the presence of entangled photon pairs in the optical signal. In the case of a system driven by a continuous coherent pump, the oscillations occur in the transient regime. We show that driving the system with pulsed coherent pumping would generate strongly antibunched photon states.

  19. Bifurcation topology transfer in nonlinear nanocantilever arrays subject to parametric and internal resonances

    Directory of Open Access Journals (Sweden)

    Souayeh Saoussen

    2014-01-01

    Full Text Available The collective nonlinear dynamics of a coupled array of nanocantilevers is investigated while taking into account the main sources of nonlinearities. The amplitude and phase equations of this device, subject to parametric and internal resonances, are analytically derived by means of a multi-modal Galerkin discretization coupled with a multiscale analysis. Based on the steady-state solutions of these equations, the frequency responses are numerically computed for a two-beam array. The effects of different parameters are investigated and several dynamical aspects are confirmed by numerical simulations. Particularly, we have demonstrated that the bifurcation topology transfer is imposed by the first nanocantilever and it can be general to the collective nonlinear dynamics of the NEMS array.

  20. Principal Resonance of Parametrically Excited Moving Viscoelastic Belts with Geometrical Nonlinearity

    Institute of Scientific and Technical Information of China (English)

    侯之超; 祖武争

    2004-01-01

    Nonlinear dynamic analysis is performed on moving belts subjected to geometric nonlinearity and initial tension fluctuation.To incorporate more accurately the damping mechanism of belt material, linear viscoelastic models are adopted in a unified form of differential operators.To circumvent high-order differential vibration equation of time-varying coefficients and with gyroscopic and nonlinear terms, where analytical solution is almost impossible, a systematic approach is presented by reforming the motion equation and directly using the method of multiple scales.To exemplify the procedure, the solutions at principal resonance are obtained and their stability conditions are derived for employing a Kelvin-Voigt model to reflect the property of the belt material.The solutions and stability conditions successfully reduce to those for using Kelvin model and elastic model, which validate the present approaches.Numerical simulations highlight the effects of tension fluctuations and translating speeds on the stability of the belt vibration.

  1. Modal interactions in primary and subharmonic resonant dynamics of imperfect microplates with geometric nonlinearities

    Institute of Scientific and Technical Information of China (English)

    Hamed Farokhi; Mergen H Ghayesh

    2016-01-01

    This paper analyses the modal interactions in the nonlinear, size-dependent dynamics of geometrically imper-fect microplates. Based on the modified couple stress theory, the equations of motion for the in-plane and out-of-plane motions are obtained employing the von Kármán plate theory as well as Kirchhoff ’s hypotheses by means of the Lagrange equations. The equations of motions are solved using the pseudo-arclength continuation technique and direct time-integration method. The system parameters are tuned to the values associated with modal interactions, and then non-linear resonant responses and energy transfer are analysed. Nonlinear motion characteristics are shown in the form of frequency-response and force-response curves, time histo-ries, phase-plane portraits, and fast Fourier transforms.

  2. Nonlinear aeroacoustic characterization of Helmholtz resonators with a local-linear neuro-fuzzy network model

    Science.gov (United States)

    Förner, K.; Polifke, W.

    2017-10-01

    The nonlinear acoustic behavior of Helmholtz resonators is characterized by a data-based reduced-order model, which is obtained by a combination of high-resolution CFD simulation and system identification. It is shown that even in the nonlinear regime, a linear model is capable of describing the reflection behavior at a particular amplitude with quantitative accuracy. This observation motivates to choose a local-linear model structure for this study, which consists of a network of parallel linear submodels. A so-called fuzzy-neuron layer distributes the input signal over the linear submodels, depending on the root mean square of the particle velocity at the resonator surface. The resulting model structure is referred to as an local-linear neuro-fuzzy network. System identification techniques are used to estimate the free parameters of this model from training data. The training data are generated by CFD simulations of the resonator, with persistent acoustic excitation over a wide range of frequencies and sound pressure levels. The estimated nonlinear, reduced-order models show good agreement with CFD and experimental data over a wide range of amplitudes for several test cases.

  3. Tunable, Room Temperature CMOS-Compatible THz Emitters Based on Nonlinear Mixing in Microdisk Resonators

    Science.gov (United States)

    Sinha, Raju; Karabiyik, Mustafa; Ahmadivand, Arash; Al-Amin, Chowdhury; Vabbina, Phani Kiran; Shur, Michael; Pala, Nezih

    2016-03-01

    We propose and investigate in detail a novel tunable, compact, room temperature terahertz (THz) emitter using individual microdisk resonators for both optical and THz waves with the capability of radiating THz field in 0.5-10 THz range with tuning frequency resolution of 0.05 THz. Enhanced THz generation is achieved by employing a nonlinear optical disk resonator with a high value of second-order nonlinearity ( χ (2)) in order to facilitate the difference-frequency generation (DFG) via nonlinear mixing with the choice of two appropriate input infrared optical waves. Efficient coupling of infrared waves from bus to the nonlinear disk is ensured by satisfying critical coupling condition. Phase matching condition for efficient DFG process is also met by employing modal phase matching technique. Our simulations show that THz output power can be reached up to milliwatt (mW) level with high optical to THz conversion efficiency. The proposed source is Silicon on Insulator (SoI) technology compatible enabling the monolithic integration with Si complementary metal-oxide-semiconductor (CMOS) electronics including plasmonic THz detectors.

  4. Nonlinear Resonance of the Rotating Circular Plate under Static Loads in Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    HU Yuda; WANG Tong

    2015-01-01

    The rotating circular plate is widely used in mechanical engineering, meanwhile the plates are often in the electromagnetic field in modern industry with complex loads. In order to study the resonance of a rotating circular plate under static loads in magnetic field, the nonlinear vibration equation about the spinning circular plate is derived according to Hamilton principle. The algebraic expression of the initial deflection and the magneto elastic forced disturbance differential equation are obtained through the application of Galerkin integral method. By mean of modified Multiple scale method, the strongly nonlinear amplitude-frequency response equation in steady state is established. The amplitude frequency characteristic curve and the relationship curve of amplitude changing with the static loads and the excitation force of the plate are obtained according to the numerical calculation. The influence of magnetic induction intensity, the speed of rotation and the static loads on the amplitude and the nonlinear characteristics of the spinning plate are analyzed. The proposed research provides the theory reference for the research of nonlinear resonance of rotating plates in engineering.

  5. Non destructive characterization of cortical bone micro-damage by nonlinear resonant ultrasound spectroscopy.

    Directory of Open Access Journals (Sweden)

    Sylvain Haupert

    Full Text Available The objective of the study was to evaluate the ability of a nonlinear ultrasound technique, the so-called nonlinear resonant ultrasound spectroscopy (NRUS technique, for detecting early microdamage accumulation in cortical bone induced by four-point bending fatigue. Small parallelepiped beam-shaped human cortical bone specimens were subjected to cyclic four-point bending fatigue in several steps. The specimens were prepared to control damage localization during four-point bending fatigue cycling and to unambiguously identify resonant modes for NRUS measurements. NRUS measurements were achieved to follow the evolution of the nonlinear hysteretic elastic behavior during fatigue-induced damage. After each fatigue step, a small number of specimens was removed from the protocol and set apart to quantitatively assess the microcrack number density and length using synchrotron radiation micro-computed tomography (SR-µCT. The results showed a significant effect of damage steps on the nonlinear hysteretic elastic behavior. No significant change in the overall length of microcracks was observed in damaged regions compared to the load-free control regions. Only an increased number of shortest microcracks, those in the lowest quartile, was noticed. This was suggestive of newly formed microcracks during the early phases of damage accumulation. The variation of nonlinear hysteretic elastic behavior was significantly correlated to the variation of the density of short microcracks. Our results suggest that the nonlinear hysteretic elastic behavior is sensitive to early bone microdamage. Therefore NRUS technique can be used to monitor fatigue microdamage progression in in vitro experiments.

  6. Theoretical investigation of nonlinear resonances in a carbon nanotube cantilever with a tip-mass under electrostatic excitation

    Science.gov (United States)

    Kim, I. K.; Lee, S. I.

    2013-09-01

    The nonlinear dynamics of a resonating carbon nanotube (CNT) cantilever having an attached mass at the tip ("tip mass") were investigated by incorporating electrostatic forces and intermolecular interactions between the CNT and a conducting plane surface. This work enables applications of CNT resonating sensors for tiny mass detection and provides a better understanding of the dynamics of CNT cantilevers. The effect of tip mass on a resonating CNT cantilever is normally characterized by the fundamental frequency shift in the linear resonance regime. However, there are more complex dynamics in the nonlinear resonance regime, such as secondary resonances with parametric excitation. The latter have been limited to nano-cantilevers without tip mass or to axially excited micro-beams. To analyze the nonlinear dynamics, we developed a differential equation model that includes both geometric and inertial nonlinear terms for the large vibration amplitudes at increasing drive forces. In our approach, we used Galerkin discretization techniques and numerical integration methods. The CNT cantilever exhibited complex nonlinear responses due to the applied AC and DC voltages and various tip masses. The nonlinear model had a softer response for increasing tip mass than those of the linear model with the same driving conditions. At low applied voltages, the cantilever had linear amplitude and phase responses at primary and secondary superharmonic resonance frequencies. The response branches were softened at the primary resonance through saddle-node (SN) bifurcation from harmonic electrostatic excitation at higher applied voltages. After SN bifurcation, the lower branch of the solution near resonance became unstable. In addition, theoretical analyses were performed on more complex nonlinear responses and stability changes with tip mass variations, such as period-doubling (PD) bifurcation at subharmonic resonance frequencies.

  7. Nonlinear magnetic resonance behavior and reversible adsorbed gas effects from trace ferromagnestism in Y-zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Iton, L.E.

    1977-01-01

    Unusual spin resonance observations made on a sample of rare earth ion-exchanged Y-zeolite have been attributed to the presence of a ferromagnetic impurity, and are qualitatively explained in terms of existing theories on nonlinear behavior in ferromagnetic resonance at high power. The effects included foldover and bistable response below 136 K, due to classical, anisotropy-based nonlinearity; above 136 K, apparent subsidiary absorption--the Suhl instability driven by coupling of low-frequency spin wave modes to the main resonance--predominated. Modification of the surface anisotropy is suggested to account for the complete suppression of the low-temperature effects when the zeolity sample was cooled in air, the high-temperature effects persisting after this cooling but with a loss of orientational anisotropy. Brief room temperature evacuation of the sample was sufficient to regenerate the original effects. Some details of the resonance behavior are very similar to recently published observations from magnetite impurities; those were there attributed to field-induced transitions. The limitations under which a field-dependent Verwey transition could be used to rationalize such observations have been schematically expounded, and the importance of the microwave field again appears to be the dominating factor.

  8. Nonlinear response of an ultracompact waveguide Fabry-Pérot resonator

    Science.gov (United States)

    Sederberg, S.; Elezzabi, A. Y.

    2013-01-01

    We experimentally demonstrate active tuning of an ultracompact silicon-on-insulator trapezoid Fabry-Pérot resonator having a volume of 5.31 μm3. We show that the ultrafast nonlinear dynamics arising from two-photon and free-carrier absorption can be used to achieve a signal attenuation of 66% in the device, and the changes in the steady-state resonant properties of the device resulting from the thermo-optic effect induce a large red-shift in its resonance of Δλ = 7.57 nm. It is envisaged that the insight gained from this class of device will be valuable in the integrated optics community as ultrafast modulators, and switches are designed to occupy smaller volumes.

  9. Controlling Lateral Fano Interference Optical Force with Au-Ge2Sb2Te5 Hybrid Nanostructure

    DEFF Research Database (Denmark)

    Cao, Tun; Bao, Jiaxin; Mao, Libang;

    2016-01-01

    We numerically demonstrate that a pronounced dipole-quadrupole (DQ) Fano resonance (FR) induced lateral force can be exerted on a dielectric particle 80 nm in radius (R-sphere = 80 nm) that is placed 5 nm above an asymmetric bow-tie nanoantenna array based on Au/Ge2Sb2Te5 dual layers. The DQ-FR-i...

  10. Controlling Lateral Fano Interference Optical Force with Au-Ge2Sb2Te5 Hybrid Nanostructure

    DEFF Research Database (Denmark)

    Cao, Tun; Bao, Jiaxin; Mao, Libang

    2016-01-01

    We numerically demonstrate that a pronounced dipole-quadrupole (DQ) Fano resonance (FR) induced lateral force can be exerted on a dielectric particle 80 nm in radius (R-sphere = 80 nm) that is placed 5 nm above an asymmetric bow-tie nanoantenna array based on Au/Ge2Sb2Te5 dual layers. The DQ-FR-i...

  11. Nonlinear dynamics of an electrically actuated imperfect microbeam resonator: Experimental investigation and reduced-order modeling

    KAUST Repository

    Ruzziconi, Laura

    2013-06-10

    We present a study of the dynamic behavior of a microelectromechanical systems (MEMS) device consisting of an imperfect clamped-clamped microbeam subjected to electrostatic and electrodynamic actuation. Our objective is to develop a theoretical analysis, which is able to describe and predict all the main relevant aspects of the experimental response. Extensive experimental investigation is conducted, where the main imperfections coming from microfabrication are detected, the first four experimental natural frequencies are identified and the nonlinear dynamics are explored at increasing values of electrodynamic excitation, in a neighborhood of the first symmetric resonance. Several backward and forward frequency sweeps are acquired. The nonlinear behavior is highlighted, which includes ranges of multistability, where the nonresonant and the resonant branch coexist, and intervals where superharmonic resonances are clearly visible. Numerical simulations are performed. Initially, two single mode reduced-order models are considered. One is generated via the Galerkin technique, and the other one via the combined use of the Ritz method and the Padé approximation. Both of them are able to provide a satisfactory agreement with the experimental data. This occurs not only at low values of electrodynamic excitation, but also at higher ones. Their computational efficiency is discussed in detail, since this is an essential aspect for systematic local and global simulations. Finally, the theoretical analysis is further improved and a two-degree-of-freedom reduced-order model is developed, which is also capable of capturing the measured second symmetric superharmonic resonance. Despite the apparent simplicity, it is shown that all the proposed reduced-order models are able to describe the experimental complex nonlinear dynamics of the device accurately and properly, which validates the proposed theoretical approach. © 2013 IOP Publishing Ltd.

  12. Coupled large earthquakes in the Baikal rift system: Response to bifurcations in nonlinear resonance hysteresis

    Directory of Open Access Journals (Sweden)

    Anatoly V. Klyuchevskii

    2013-11-01

    Full Text Available The current lithospheric geodynamics and tectonophysics in the Baikal rift are discussed in terms of a nonlinear oscillator with dissipation. The nonlinear oscillator model is applicable to the area because stress change shows up as quasi-periodic inharmonic oscillations at rifting attractor structures (RAS. The model is consistent with the space-time patterns of regional seismicity in which coupled large earthquakes, proximal in time but distant in space, may be a response to bifurcations in nonlinear resonance hysteresis in a system of three oscillators corresponding to the rifting attractors. The space-time distribution of coupled MLH > 5.5 events has been stable for the period of instrumental seismicity, with the largest events occurring in pairs, one shortly after another, on two ends of the rift system and with couples of smaller events in the central part of the rift. The event couples appear as peaks of earthquake ‘migration’ rate with an approximately decadal periodicity. Thus the energy accumulated at RAS is released in coupled large events by the mechanism of nonlinear oscillators with dissipation. The new knowledge, with special focus on space-time rifting attractors and bifurcations in a system of nonlinear resonance hysteresis, may be of theoretical and practical value for earthquake prediction issues. Extrapolation of the results into the nearest future indicates the probability of such a bifurcation in the region, i.e., there is growing risk of a pending M ≈ 7 coupled event to happen within a few years.

  13. Non-stationary resonance dynamics of a nonlinear sonic vacuum with grounding supports

    Science.gov (United States)

    Koroleva (Kikot), I. P.; Manevitch, L. I.; Vakakis, Alexander F.

    2015-11-01

    In a recent work [L.I. Manevitch, A.F.Vakakis, Nonlinear oscillatory acoustic vacuum, SIAM Journal of Applied Mathematics 74(6) (2014), 1742-1762] it was shown that a periodic chain of linearly coupled particles performing low-energy in-plane transverse oscillations behaves as a strongly nonlinear sonic vacuum (with corresponding speed of sound equal to zero). In this work we consider the grounded version of this system by coupling each particle to the ground through lateral springs in order to study the effect of the grounding stiffness on the strongly nonlinear dynamics. In that context we consider the simplest possible such system consisting of two coupled particles and present analytical and numerical studies of the non-stationary planar dynamics. The most significant limiting case corresponding to predominant low energy transversal excitations is considered by taking into account leading order geometric nonlinearities. Then we show that the grounded system behaves as a nonlinear sonic vacuum due to the purely cubic stiffness nonlinearities in the governing equations of motion and the complete absence of any linear stiffness terms. Under certain assumptions the nonlinear normal modes (i.e., the time-periodic nonlinear oscillations) in the configuration space of this system coincide with those of the corresponding linear one, so they obey the same orthogonality relations. Moreover, we analytically find that there are two transitions in the dynamics of this system, with the parameter governing these transitions being the relation between the lateral (grounding) and the interchain stiffnesses. The first transition concerns a bifurcation of one of the nonlinear normal modes (NNMs), whereas the second provides conditions for intense energy transfers and mixing between the NNMs. The drastic effects of these bifurcations on the non-stationary resonant dynamics are discussed. Specifically, the second transition relates to strongly non-stationary dynamics, and signifies

  14. Assessment of numerical methods for the solution of fluid dynamics equations for nonlinear resonance systems

    Science.gov (United States)

    Przekwas, A. J.; Yang, H. Q.

    1989-01-01

    The capability of accurate nonlinear flow analysis of resonance systems is essential in many problems, including combustion instability. Classical numerical schemes are either too diffusive or too dispersive especially for transient problems. In the last few years, significant progress has been made in the numerical methods for flows with shocks. The objective was to assess advanced shock capturing schemes on transient flows. Several numerical schemes were tested including TVD, MUSCL, ENO, FCT, and Riemann Solver Godunov type schemes. A systematic assessment was performed on scalar transport, Burgers' and gas dynamic problems. Several shock capturing schemes are compared on fast transient resonant pipe flow problems. A system of 1-D nonlinear hyperbolic gas dynamics equations is solved to predict propagation of finite amplitude waves, the wave steepening, formation, propagation, and reflection of shocks for several hundred wave cycles. It is shown that high accuracy schemes can be used for direct, exact nonlinear analysis of combustion instability problems, preserving high harmonic energy content for long periods of time.

  15. Design of triply-resonant microphotonic parametric oscillators based on Kerr nonlinearity.

    Science.gov (United States)

    Zeng, Xiaoge; Popović, Miloš A

    2014-06-30

    We propose optimal designs for triply-resonant optical parametric oscillators (OPOs) based on degenerate four-wave mixing (FWM) in microcavities. We show that optimal designs in general call for different external coupling to pump and signal/idler resonances. We provide a number of normalized performance metrics including threshold pump power and maximum achievable conversion efficiency for OPOs with and without two-photon (TPA) and free-carrier absorption (FCA). We find that the maximum achievable conversion efficiency is bound to an upper limit by nonlinear and free-carrier losses independent of pump power, while linear losses only increase the pump power required to achieve a certain conversion efficiency. The results of this work suggest unique advantages in on-chip implementations that allow explicit engineering of resonances, mode field overlaps, dispersion, and wavelength-and mode-selective coupling. We provide universal design curves that yield optimum designs, and give example designs of microring-resonator-based OPOs in silicon at the wavelengths 1.55 μm (with TPA) and 2.3 μm (no TPA) as well as in silicon nitride (Si(3)N(4)) at 1.55 μm. For typical microcavity quality factor of 10(6), we show that the oscillation threshold in excitation bus can be well into the sub-mW regime for silicon microrings and a few mW for silicon nitride microrings. The conversion efficiency can be a few percent when pumped at 10 times of the threshold. Next, based on our results, we suggest a family of synthetic "photonic molecule"-like, coupled-cavity systems to implement optimum FWM, where structure design for control of resonant wavelengths can be separated from that of optimizing nonlinear conversion efficiency, and where furthermore pump, signal, and idler coupling to bus waveguides can be controlled independently, using interferometric cavity supermode coupling as an example. Finally, consideration of these complex geometries calls for a generalization of the nonlinear

  16. Zinc Oxide Nanocrystals for Non-resonant Nonlinear Optical Microscopy in Biology and Medicine.

    Science.gov (United States)

    Kachynski, Aliaksandr V; Kuzmin, Andrey N; Nyk, Marcin; Roy, Indrajit; Prasad, Paras N

    2008-07-24

    In this paper we show that biocompatible zinc oxide (ZnO) nanocrystals (NCs) having non-centrosymmetric structure can be used as non-resonant nonlinear optical probes for targeting in bioimaging applications in vitro by use of the second order processes of second harmonic and sum frequency generation, as well as the third order process of four wave mixing. These non-resonant processes provide advantages above and beyond traditional two-photon bioimaging: (i) the probes do not photo-bleach; (ii) the input wavelength can be judiciously selected; and (iii) no heat is dissipated into the cells, ensuring longer cell viability and ultimately longer imaging times. ZnO NCs have been synthesized in organic media by using a non-hydrolytic sol-gel process, and subsequently dispersed in aqueous media using phospholipid micelles, and incorporated with the biotargeting molecule folic acid (FA). Sum Frequency, Second Harmonic and non-resonant four wave mixing non-linear signals from this stable dispersion of ZnO NCs, targeted to the live tumor (KB) cells were used for imaging. Robust intracellular accumulation of the targeted (FA incorporated) ZnO nanocrystals could be observed, without any indication of cytotoxicity.

  17. Modified Lindstedt-Poincaré Method for Obtaining Resonance Periodic Solutions of Nonlinear Non-autonomous Oscillators

    Institute of Scientific and Technical Information of China (English)

    郭抗抗; 曹树谦

    2014-01-01

    A modified Lindstedt-Poincaré (LP) method for obtaining the resonance periodic solutions of nonlinear non-autonomous vibration systems is proposed in this paper. In the modified method, nonlinear non-autonomous equa-tions are converted into a group of linear ordinary differential equations by introducing a set of simple transformations. An approximate resonance solution for the original equation can then be obtained. The periodic solutions of primary, super-harmonic, sub-harmonic, zero-frequency and combination resonances can be solved effectively using the modi-fied method. Some examples, such as damped cubic nonlinear systems under single and double frequency excitation, and damped quadratic nonlinear systems under double frequency excitation, are given to illustrate its convenience and effectiveness. Using the modified LP method, the first-order approximate solutions for each equation are obtained. By comparison, the modified method proposed in this paper produces the same results as the method of multiple scales.

  18. Nonlinear free vibrations of beams in space due to internal resonance

    Science.gov (United States)

    Stoykov, S.; Ribeiro, P.

    2011-08-01

    The geometrically nonlinear free vibrations of beams with rectangular cross section are investigated using a p-version finite element method. The beams may vibrate in space, hence they may experience longitudinal, torsional and non-planar bending deformations. The model is based on Timoshenko's theory for bending and assumes that, under torsion, the cross section rotates as a rigid body and is free to warp in the longitudinal direction, as in Saint-Venant's theory. The geometrical nonlinearity is taken into account by considering Green's nonlinear strain tensor. Isotropic and elastic beams are investigated and generalised Hooke's law is used. The equation of motion is derived by the principle of virtual work. Mostly clamped-clamped beams are investigated, although other boundary conditions are considered for validation purposes. Employing the harmonic balance method, the differential equations of motion are converted into a nonlinear algebraic form and then solved by a continuation method. One constant term, odd and even harmonics are assumed in the Fourier series and convergence with the number of harmonics is analysed. The variation of the amplitude of vibration with the frequency of vibration is determined and presented in the form of backbone curves. Coupling between modes is investigated, internal resonances are found and the ensuing multimodal oscillations are described. Some of the couplings discovered lead from planar oscillations to oscillations in the three dimensional space.

  19. Nonlinear dynamics of three-magnon process driven by ferromagnetic resonance in yttrium iron garnet

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, R. O. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Centro Interdisciplinar de Ciências da Natureza, Universidade Federal da Integração Latino-Americana, 85867-970 Foz do Iguaçu, PR (Brazil); Holanda, J.; Azevedo, A.; Rezende, S. M., E-mail: rezende@df.ufpe.br [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Vilela-Leão, L. H. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Centro Acadêmico do Agreste, Universidade Federal de Pernambuco, 55002-970 Caruaru, PE (Brazil); Rodríguez-Suárez, R. L. [Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago (Chile)

    2015-05-11

    We report an investigation of the dynamics of the three-magnon splitting process associated with the ferromagnetic resonance (FMR) in films of the insulating ferrimagnet yttrium iron garnet (YIG). The experiments are performed with a 6 μm thick YIG film close to a microstrip line fed by a microwave generator operating in the 2–6 GHz range. The magnetization precession is driven by the microwave rf magnetic field perpendicular to the static magnetic field, and its dynamics is observed by monitoring the amplitude of the FMR absorption peak. The time evolution of the amplitude reveals that if the frequency is lowered below a critical value of 3.3 GHz, the FMR mode pumps two magnons with opposite wave vectors that react back on the FMR, resulting in a nonlinear dynamics of the magnetization. The results are explained by a model with coupled nonlinear equations describing the time evolution of the magnon modes.

  20. Non-linear MHD modeling of edge localized mode cycles and mitigation by resonant magnetic perturbations

    Science.gov (United States)

    Orain, François; Bécoulet, M.; Morales, J.; Huijsmans, G. T. A.; Dif-Pradalier, G.; Hoelzl, M.; Garbet, X.; Pamela, S.; Nardon, E.; Passeron, C.; Latu, G.; Fil, A.; Cahyna, P.

    2015-01-01

    The dynamics of a multi-edge localized mode (ELM) cycle as well as the ELM mitigation by resonant magnetic perturbations (RMPs) are modeled in realistic tokamak X-point geometry with the non-linear reduced MHD code JOREK. The diamagnetic rotation is found to be a key parameter enabling us to reproduce the cyclical dynamics of the plasma relaxations and to model the near-symmetric ELM power deposition on the inner and outer divertor target plates consistently with experimental measurements. Moreover, the non-linear coupling of the RMPs with unstable modes are found to modify the edge magnetic topology and induce a continuous MHD activity in place of a large ELM crash, resulting in the mitigation of the ELMs. At larger diamagnetic rotation, a bifurcation from unmitigated ELMs—at low RMP current—towards fully suppressed ELMs—at large RMP current—is obtained.

  1. Magnetic resonance imaging with nonlinear gradient fields signal encoding and image reconstruction

    CERN Document Server

    Schultz, Gerrit

    2013-01-01

    Within the past few decades magnetic resonance imaging has become one of the most important imaging modalities in medicine. For a reliable diagnosis of pathologies further technological improvements are of primary importance. This text deals with a radically new approach of image encoding: The fundamental principle of gradient linearity is challenged by investigating the possibilities of acquiring anatomical images with the help of nonlinear gradient fields. Besides a thorough theoretical analysis with a focus on signal encoding and image reconstruction, initial hardware implementations are tested using phantom as well as in-vivo measurements. Several applications are presented that give an impression about the implications that this technological advancement may have for future medical diagnostics.   Contents n  Image Reconstruction in MRI n  Nonlinear Gradient Encoding: PatLoc Imaging n  Presentation of Initial Hardware Designs n  Basics of Signal Encoding and Image Reconstruction in PatLoc Imaging n ...

  2. Approximate Super- and Sub-harmonic Response of a Multi-DOFs System with Local Cubic Nonlinearities under Resonance

    Directory of Open Access Journals (Sweden)

    Yang CaiJin

    2012-01-01

    nonlinear response of system at super/sub harmonic resonance. For many situations, single resonance mode is often observed to be leading as system enters into super/sub harmonic resonance. In this case, the single modal natural resonance theory can be applied to reduce the system model and a simplified model with only a single DOF is always obtained. Thus, an approximate solution and the analytical expression of frequency response relation are then derived using classical perturbation analysis. While the system is controlled by multiple modes, modal analysis for linearized system is used to decide dominant modes. The reduced model governed by these relevant modes is found and results in an approximate numerical solutions. An illustrative example of the discrete mass-spring-damper nonlinear vibration system with ten DOFs is examined. The approximation results are validated by comparing them with the calculations from direct numerical integration of the equation of motion of the original nonlinear system. Comparably good agreements are obtained.

  3. Off-Resonant Third-Order Optical Nonlinearity of Au Nanoparticle Array by Femtosecond Z-scan Measurement

    Institute of Scientific and Technical Information of China (English)

    WANG Kai; LONG Hua; FU Ming; YANG Guang; LU Pei-Xiang

    2010-01-01

    @@ A periodic triangular-shaped Au nanoparticle array is fabricated on a quartz substrate using nanosphere lithography and pulled laser deposition,and the linear and nonlinear optical properties of metal particles are studied.The morphology of the polystyrene nanosphere mask(D=820 nm)and the A u nanoparticle array are investigated by scanning electron microscopy.The surface plasmon resonance absorption peak is observed at 606 nm,which is in good agreement with the calculated result using the discrete dipole approximation method.By performing the Z-scan method with femtosecond laser(800nm,50fs),the optical nonlinearities of Au nanoparticle array are determined.The results show that the Au particles exhibit negative nonlinear absorption and positive nonlinear refractive index with the effective third-order optical nonlinear susceptibility Xeff(3)can be up to(8.8±1.0)×10-10 esu under non-resonant femtosecond laser excitation.

  4. Phase locking and quantum statistics in a parametrically driven nonlinear resonator

    Science.gov (United States)

    Hovsepyan, G. H.; Shahinyan, A. R.; Chew, Lock Yue; Kryuchkyan, G. Yu.

    2016-04-01

    We discuss phase-locking phenomenon at low-level of quanta and quantum statistics for parametrically driven nonlinear Kerr resonator (PDNR). Oscillatory mode of PDNR is created in the process of a degenerate down-conversion of photons under interaction with a train of external Gaussian pulses. We calculate the distribution of photon-number states, the second-order correlation function of photons, the Wigner functions of cavity mode showing two-fold symmetry in phase space, and we analyze formation of phase-locked states in the regular as well as the quantum chaotic regime of the PDNR.

  5. Nonlinear sub-cyclotron resonance as a formation mechanism for gaps in banded chorus

    CERN Document Server

    Fu, Xiangrong; Dong, Chuanfei; Gary, S Peter

    2015-01-01

    An interesting characteristic of magnetospheric chorus is the presence of a frequency gap at $\\omega \\simeq 0.5\\Omega_e$, where $\\Omega_e$ is the electron cyclotron angular frequency. Recent chorus observations sometimes show additional gaps near $0.3\\Omega_e$ and $0.6\\Omega_e$. Here we present a novel nonlinear mechanism for the formation of these gaps using Hamiltonian theory and test-particle simulations in a homogeneous, magnetized, collisionless plasma. We find that an oblique whistler wave with frequency at a fraction of the electron cyclotron frequency can resonate with electrons, leading to effective energy exchange between the wave and particles.

  6. Nonlinear dynamic singularity analysis of two interconnected synchronous generator system with 1:3 internal resonance and parametric principal resonance

    Institute of Scientific and Technical Information of China (English)

    Xiaodong WANG; Yushu CHEN; Lei HOU

    2015-01-01

    The bifurcation analysis of a simple electric power system involving two synchronous generators connected by a transmission network to an infinite-bus is carried out in this paper. In this system, the infinite-bus voltage are considered to maintain two fluctuations in the amplitude and phase angle. The case of 1:3 internal resonance between the two modes in the presence of parametric principal resonance is considered and examined. The method of multiple scales is used to obtain the bifurcation equations of this system. Then, by employing the singularity method, the transition sets determining different bifurcation patterns of the system are obtained and analyzed, which reveal the effects of the infinite-bus voltage amplitude and phase fluctuations on bifurcation patterns of this system. Finally, the bifurcation patterns are all examined by bifurcation diagrams. The results obtained in this paper will contribute to a better understanding of the complex nonlinear dynamic behaviors in a two-machine infinite-bus (TMIB) power system.

  7. Automated System of Study Nonlinear Processes in Electro-vacuum Devices with Open Resonant Periodic Structures

    Directory of Open Access Journals (Sweden)

    G.S. Vorobyov

    2014-04-01

    Full Text Available The article describes the experimental equipment and the results of investigations of nonlinear processes occurring during the excitation of electromagnetic oscillations in the resonant electron beam devices such as an orotron-generator of diffraction radiation. These devices are finding wide application in physics and microwave technology, now. A technique for experimental research, which bases on the using of the universal electro vacuum equipment diffraction radiation analyzer and the microprocessor system for collecting and processing data. The experimental investigations results of the energy and frequency characteristics for the most common modes of the excitation oscillations in the open resonant systems such as an orotron. The implementations on the optimum modes for the oscillations excitation in such devices were recommended.

  8. Resonances of a nonlinear SDOF system with time-delay in linear feedback control

    Energy Technology Data Exchange (ETDEWEB)

    El-Bassiouny, A F [Mathematics Department, Faculty of Science, Benha University, Benha 13518 (Egypt); El-kholy, S [Department of Mathematics, Faculty of Science, Menoufia University, Shebin El-kom (Egypt)], E-mail: atef_elbassiouny@yahoo.com

    2010-01-15

    The primary and subharmonic resonances of a nonlinear single-degree-of-freedom (SDOF) system under feedback control with a time delay have been studied by means of an asymptotic perturbation technique. Both external (forcing) and parametric excitations have been included. By means of the averaging method and multiple scales method, two slow-flow equations for the amplitude and phase of the primary and subharmonic resonances and all other parameters are obtained, respectively. The steady state solutions (fixed points) for the original system are investigated. The stability of the fixed points is examined by using the variational method. The effect of the feedback gains, time-delay, the coefficient of cubic term, the coefficients of external and parametric excitations on the steady state responses are investigated and the results are presented as plots of the steady state response amplitude versus the detuning parameter. The results obtained by the two methods are in excellent agreement. There exist saddle node bifurcations for the case of primary resonance and the solutions lose stability for the case of resonance subharmonic.

  9. All optical NAND gate based on nonlinear photonic crystal ring resonator

    Directory of Open Access Journals (Sweden)

    Somaye Serajmohammadi

    2016-06-01

    Full Text Available In this paper we proposed a new design for all optical NAND gate. By combining nonlinear Kerr effect with photonic crystal ring resonators, we designed an all optical NAND gate. A typical NAND gate is a logic device with one bias and two logic input and one output ports. It has four different combinations for its logic input ports. The output port of the NAND gate is OFF, when both logic ports are ON, otherwise the output port will be ON. The switching power threshold obtained for this structure equals to 1.5 kW/μm2. For designing the proposed optical logic gate we employed one resonant ring whose resonant wavelength is at 1554 nm. The functionality of the proposed NAND gate depends on the operation of this resonant ring. When the power intensity of optical waves is less than the switching threshold the ring will couple optical waves into drop waveguide otherwise the optical waves will propagate on the bus waveguide.

  10. Nonlinear series resonance and standing waves in dual-frequency capacitive discharges

    Science.gov (United States)

    Wen, De-Qi; Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J.; Wang, You-Nian

    2017-01-01

    It is well-known that the nonlinear series resonance in a high frequency capacitive discharge enhances the electron power deposition and also creates standing waves which produce radially center-high rf voltage profiles. In this work, the dynamics of series resonance and wave effects are examined in a dual-frequency driven discharge, using an asymmetric radial transmission line model incorporating a Child law sheath. We consider a cylindrical argon discharge with a conducting electrode radius of 15 cm, gap length of 3 cm, with a base case having a 60 MHz high frequency voltage of 250 V and a 10 MHz low frequency voltage of 1000 V, with a high frequency phase shift {φ\\text{H}}=π between the two frequencies. For this phase shift there is only one sheath collapse, and the time-averaged spectral peaks of the normalized current density at the center are mainly centered on harmonic numbers 30 and 50 of the low frequency, corresponding to the first standing wave resonance frequency and the series resonance frequency, respectively. The effects of the waves on the series resonance dynamics near the discharge center give rise to significant enhancements in the electron power deposition, compared to that near the discharge edge. Adjusting the phase shift from π to 0, or decreasing the low frequency from 10 to 2 MHz, results in two or more sheath collapses, respectively, making the dynamics more complex. The sudden excitation of the perturbed series resonance current after the sheath collapse results in a current oscillation amplitude that is estimated from analytical and numerical calculations. Self-consistently determining the dc bias and including the conduction current is found to be important. The subsequent slow time variation of the high frequency oscillation is analyzed using an adiabatic theory.

  11. Fano lineshapes of 'Peak-tracking chip' spatial profiles analyzed with correlation analysis for bioarray imaging and refractive index sensing

    KAUST Repository

    Bougot-Robin, K.

    2013-05-22

    The asymmetric Fano resonance lineshapes, resulting from interference between background and a resonant scattering, is archetypal in resonant waveguide grating (RWG) reflectivity. Resonant profile shift resulting from a change of refractive index (from fluid medium or biomolecules at the chip surface) is classically used to perform label-free sensing. Lineshapes are sometimes sampled at discretized “detuning” values to relax instrumental demands, the highest reflectivity element giving a coarse resonance estimate. A finer extraction, needed to increase sensor sensitivity, can be obtained using a correlation approach, correlating the sensed signal to a zero-shifted reference signal. Fabrication process is presented leading to discrete Fano profiles. Our findings are illustrated with resonance profiles from silicon nitride RWGs operated at visible wavelengths. We recently demonstrated that direct imaging multi-assay RWGs sensing may be rendered more reliable using “chirped” RWG chips, by varying a RWG structure parameter. Then, the spatial reflectivity profiles of tracks composed of RWGs units with slowly varying filling factor (thus slowly varying resonance condition) are measured under monochromatic conditions. Extracting the resonance location using spatial Fano profiles allows multiplex refractive index based sensing. Discretization and sensitivity are discussed both through simulation and experiment for different filling factor variation, here Δf=0.0222 and Δf=0.0089. This scheme based on a “Peak-tracking chip” demonstrates a new technique for bioarray imaging using a simpler set-up that maintains high performance with cheap lenses, with down to Δn=2×10-5 RIU sensitivity for the highest sampling of Fano lineshapes. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  12. Vibronic motion with joint angstrom-femtosecond resolution observed through Fano progressions recorded within one molecule.

    Science.gov (United States)

    Lee, Joonhee; Perdue, Shawn M; Rodriguez Perez, Alejandro; Apkarian, Vartkess Ara

    2014-01-28

    Electroluminescence (EL) in scanning tunneling microscopy (STM), which enables spectroscopy with submolecular spatial resolution, is shown to be due to radiative ionization with vibronic shape resonances that carry Fano line profiles. Since Fano progressions retain phase information, the spectra can be transformed to the time domain to reconstruct the vibronic motion. In effect, measurements within a molecule are accessible with joint space-time resolution at the Å-fs limit. We demonstrate this through EL-STM on the Jahn-Teller-active Zn-etioporphyrin radical anion and visualize the orbiting motion of scattered electrons upon sudden reduction and oxidation. We discuss the elements that enable spectroscopy with submolecular spatial resolution through EL-STM and the closely related STM-Raman process.

  13. Nonlinear magneto-optical resonances for systems with J~100 observed in K2 molecules

    CERN Document Server

    Auzinsh, M; Fescenko, I; Kalvans, L; Tamanis, M

    2012-01-01

    We present the results of an experimental as well as theoretical study of nonlinear magneto-optical resonances in diatomic potassium molecules in the electronic ground state with large values of the angular momentum quantum number J~100. At zero magnetic field, the absorption transitions are suppressed because of population trapping in the ground state due to Zeeman coherences between magnetic sublevels of this state along with depopulation pumping. The destruction of such coherences in an external magnetic field was used to study the resonances in this work. K2 molecules were formed in a glass cell filled with potassium metal at a temperature above 150^{\\circ}C. The cell was placed in an oven and was located in a homogeneous magnetic field B, which was scanned from zero to 0.7 T. Q-type and R-type transitions were excited with a tunable, single-mode diode laser at a wavelength of 661 nm. Well pronounced nonlinear Hanle effect signals were observed in the intensities of the linearly polarized components of th...

  14. Nonlinear dynamics of spring softening and hardening in folded-mems comb drive resonators

    KAUST Repository

    Elshurafa, Amro M.

    2011-08-01

    This paper studies analytically and numerically the spring softening and hardening phenomena that occur in electrostatically actuated microelectromechanical systems comb drive resonators utilizing folded suspension beams. An analytical expression for the electrostatic force generated between the combs of the rotor and the stator is derived and takes into account both the transverse and longitudinal capacitances present. After formulating the problem, the resulting stiff differential equations are solved analytically using the method of multiple scales, and a closed-form solution is obtained. Furthermore, the nonlinear boundary value problem that describes the dynamics of inextensional spring beams is solved using straightforward perturbation to obtain the linear and nonlinear spring constants of the beam. The analytical solution is verified numerically using a Matlab/Simulink environment, and the results from both analyses exhibit excellent agreement. Stability analysis based on phase plane trajectory is also presented and fully explains previously reported empirical results that lacked sufficient theoretical description. Finally, the proposed solutions are, once again, verified with previously published measurement results. The closed-form solutions provided are easy to apply and enable predicting the actual behavior of resonators and gyroscopes with similar structures. © 2011 IEEE.

  15. Monitoring accelerated carbonation on standard Portland cement mortar by nonlinear resonance acoustic test

    Science.gov (United States)

    Eiras, J. N.; Kundu, T.; Popovics, J. S.; Monzó, J.; Borrachero, M. V.; Payá, J.

    2015-03-01

    Carbonation is an important deleterious process for concrete structures. Carbonation begins when carbon dioxide (CO2) present in the atmosphere reacts with portlandite producing calcium carbonate (CaCO3). In severe carbonation conditions, C-S-H gel is decomposed into silica gel (SiO2.nH2O) and CaCO3. As a result, concrete pore water pH decreases (usually below 10) and eventually steel reinforcing bars become unprotected from corrosion agents. Usually, the carbonation of the cementing matrix reduces the porosity, because CaCO3 crystals (calcite and vaterite) occupy more volume than portlandite. In this study, an accelerated carbonation-ageing process is conducted on Portland cement mortar samples with water to cement ratio of 0.5. The evolution of the carbonation process on mortar is monitored at different levels of ageing until the mortar is almost fully carbonated. A nondestructive technique based on nonlinear acoustic resonance is used to monitor the variation of the constitutive properties upon carbonation. At selected levels of ageing, the compressive strength is obtained. From fractured surfaces the depth of carbonation is determined with phenolphthalein solution. An image analysis of the fractured surfaces is used to quantify the depth of carbonation. The results from resonant acoustic tests revealed a progressive increase of stiffness and a decrease of material nonlinearity.

  16. On the Nonlinear Dynamics of a Doubly Clamped Microbeam near Primary Resonance

    KAUST Repository

    Jaber, Nizar R.

    2017-04-07

    This work aims to investigate theoretically and experimentally various nonlinear dynamic behaviors of a doubly clamped microbeam near its primary resonance. Mainly, we investigate the transition behavior from hardening, mixed, and then softening behavior. We show in a single frequency-response curve, under a constant voltage load, the transition from hardening to softening behavior demonstrating the dominance of the quadratic electrostatic nonlinearity over the cubic geometric nonlinearity of the beam as the motion amplitudes becomes large, which may lead eventually to dynamic pull-in. The microbeam is fabricated using polyimide as a structural layer coated with nickel from top and chromium and gold layers from the bottom. Frequency sweep tests are conducted for different values of DC bias revealing hardening, mixed, and softening behavior of the microbeam. A multi-mode Galerkin model combined with a shooting technique are implemented to generate the frequency response curves and to analyze the stability of the periodic motions using the Floquet theory. The simulated curves show good agreement with the experimental data.

  17. Passive suppression of helicopter ground resonance using nonlinear energy sinks attached on the helicopter blades

    Science.gov (United States)

    Bergeot, B.; Bellizzi, S.; Cochelin, B.

    2017-03-01

    This paper investigates the passive control of a rotor instability named helicopter Ground Resonance (GR). The passive device consists of a set of essential cubic nonlinear absorbers named Nonlinear Energy Sinks (NES) each of them positioned on a blade. A dynamic model reproducing helicopter GR instability is presented and transformed to a time-invariant nonlinear system using a multi-blade coordinate transformation based on Fourier transform mapping the dynamic state variables into a non-rotating reference frame. Combining complexification, slow/fast partition of the dynamics and averaging procedure, a reduced model is obtained which allowed us to use the so-called geometric singular perturbation analysis to characterize the steady state response regimes. As in the case of a NES attached to the fuselage, it is shown that under suitable conditions, GR instability can be completely suppressed, partially suppressed through periodic response or strongly modulated response. Relevant analytical results are compared, for validation purposes, to direct integration of the reference and reduced models.

  18. Parametric system identification of resonant micro/nanosystems operating in a nonlinear response regime

    Science.gov (United States)

    Sabater, A. B.; Rhoads, J. F.

    2017-02-01

    The parametric system identification of macroscale resonators operating in a nonlinear response regime can be a challenging research problem, but at the micro- and nanoscales, experimental constraints add additional complexities. For example, due to the small and noisy signals micro/nanoresonators produce, a lock-in amplifier is commonly used to characterize the amplitude and phase responses of the systems. While the lock-in enables detection, it also prohibits the use of established time-domain, multi-harmonic, and frequency-domain methods, which rely upon time-domain measurements. As such, the only methods that can be used for parametric system identification are those based on fitting experimental data to an approximate solution, typically derived via perturbation methods and/or Galerkin methods, of a reduced-order model. Thus, one could view the parametric system identification of micro/nanosystems operating in a nonlinear response regime as the amalgamation of four coupled sub-problems: nonparametric system identification, or proper experimental design and data acquisition; the generation of physically consistent reduced-order models; the calculation of accurate approximate responses; and the application of nonlinear least-squares parameter estimation. This work is focused on the theoretical foundations that underpin each of these sub-problems, as the methods used to address one sub-problem can strongly influence the results of another. To provide context, an electromagnetically transduced microresonator is used as an example. This example provides a concrete reference for the presented findings and conclusions.

  19. Tuned longitudinal surface plasmon resonance and third-order nonlinear optical properties of gold nanorods.

    Science.gov (United States)

    Tsutsui, Yushi; Hayakawa, Tomokatsu; Kawamura, Go; Nogami, Masayuki

    2011-07-08

    In order to elucidate the relationship for third-order nonlinear optical properties of anisotropic metal nanoparticles between the incident laser wavelength and surface plasmon resonance (SPR) wavelength, gold nanorods (GNRs) with a tuned longitudinal SPR mode in frequency were prepared by seed-mediated methods with two different surfactants, cetyltrimethylammonium bromide (CTAB) and benzyldimethylammonium chloride (BDAC). The real and imaginary parts of the third-order nonlinear optical susceptibilities χ(3) were examined by near-infrared (800 nm) femtosecond Z-scan and I-scan techniques for various gold sols with SPR wavelengths of 530 nm (spheres), 800 nm (nanorods) and 1000 nm (nanorods), named as 530GNSs, 800GNRs and 1000GNRs, respectively. All the samples showed intrinsically third-order nonlinear optical refractive responses. However, as for the real part of χ(3) for one particle, 800GNRs whose plasmon peak was tuned to the incident laser wavelength exhibited a Reχ(3) value 45 times stronger than 530GNSs. More interestingly, the imaginary part of χ(3) was more greatly influenced at the tuned SPR wavelength. Here we first demonstrate that 800GNRs showed plasmon-enhanced saturable absorption (SA) due to a longitudinal SPR tuned to the incident laser wavelength.

  20. Modelling the nonlinear behaviour of double walled carbon nanotube based resonator with curvature factors

    Science.gov (United States)

    Patel, Ajay M.; Joshi, Anand Y.

    2016-10-01

    This paper deals with the nonlinear vibration analysis of a double walled carbon nanotube based mass sensor with curvature factor or waviness, which is doubly clamped at a source and a drain. Nonlinear vibrational behaviour of a double-walled carbon nanotube excited harmonically near its primary resonance is considered. The double walled carbon nanotube is harmonically excited by the addition of an excitation force. The modelling involves stretching of the mid plane and damping as per phenomenon. The equation of motion involves four nonlinear terms for inner and outer tubes of DWCNT due to the curved geometry and the stretching of the central plane due to the boundary conditions. The vibrational behaviour of the double walled carbon nanotube with different surface deviations along its axis is analyzed in the context of the time response, Poincaré maps and Fast Fourier Transformation diagrams. The appearance of instability and chaos in the dynamic response is observed as the curvature factor on double walled carbon nanotube is changed. The phenomenon of Periodic doubling and intermittency are observed as the pathway to chaos. The regions of periodic, sub-harmonic and chaotic behaviour are clearly seen to be dependent on added mass and the curvature factors in the double walled carbon nanotube. Poincaré maps and frequency spectra are used to explicate and to demonstrate the miscellany of the system behaviour. With the increase in the curvature factor system excitations increases and results in an increase of the vibration amplitude with reduction in excitation frequency.

  1. Theoretical Analysis and Numerical Simulation of Resonances and Stability of a Piecewise Linear-Nonlinear Vibration Isolation System

    Directory of Open Access Journals (Sweden)

    X. Gao

    2014-01-01

    Full Text Available A methodology is presented to study the resonance and stability for a single-degree-of-freedom (SDOF system with a piecewise linear-nonlinear stiffness term (i.e., one piece is linear and the other is weakly nonlinear. Firstly, the exact response of the linear governing equation is obtained, and a modified perturbation method is applied to finding the approximate solution of the weakly nonlinear equation. Then, the primary and 1/2 subharmonic resonances are obtained by imposing continuity conditions and periodicity conditions. Furthermore, Jacobian matrix is derived to investigate the stability of resonance responses. Finally, the results of theoretical study are compared with numerical results, and a good agreement is observed.

  2. Linear and nonlinear resonance features of an erbium-doped fibre ring laser under cavity-loss modulation

    Indian Academy of Sciences (India)

    Aditi Ghosh; R Vijaya

    2014-07-01

    The continuous-wave output of a single-mode erbium-doped fibre ring laser when subjected to cavity-loss modulation is found to exhibit linear as well as nonlinear resonances. At sufficiently low driving amplitude, the system resembles a linear damped oscillator. At higher amplitudes, the dynamical study of these resonances shows that the behaviour of the system exhibits features of a nonlinear damped oscillator under harmonic modulation. These nonlinear dynamical features, including harmonic and subharmonic resonances, have been studied experimentally and analysed with the help of a simple time-domain and frequency-domain information obtained from the output of the laser. All the studies are restricted to the modulation frequency lying in a regime near the relaxation oscillation frequency.

  3. Controlling the dynamical behavior of nonlinear fiber ring resonators with balanced loss and gain

    CERN Document Server

    Deka, Jyoti P; Sarma, Amarendra K

    2015-01-01

    We show the possibility of controlling the dynamical behavior of a single fiber ring (SFR) resonator system with the fiber being an amplified (gain) channel and the ring being attenuated (loss) nonlinear dielectric medium. The system considered here is a simple alteration in the basic building block of the parity time (PT) symmetric synthetic coupler structures reported in A. Regensburger et al., Nature 488, 167 (2012). We find that this result in a dynamically controllable algorithm for the chaotic dynamics inherent in the system. We have also shown the dependence of the period doubling point upon the input amplitude, emphasizing on the dynamical aspects of our system. Moreover, the fact that the resonator essentially plays the role of a damped harmonic oscillator has been elucidated with the non-zero intensity inside the resonator due to constant influx of input light. This study may be a step forward to further investigations in regard to the inter-connectivity between the PT symmetry and chaos along with ...

  4. ON THE RESONANT GENERATION OF WEAKLY NONLINEAR STOKES WAVES IN REGIONS WITH FAST VARYING TOPOGRAPHY AND FREE SURFACE CURRENT

    Institute of Scientific and Technical Information of China (English)

    黄虎; 周锡礽

    2001-01-01

    The effect of nonlinearity on the free surface wave resonated by an incident flow over rippled beds, which consist of fast varying topography superimposed on an otherwise slowly varying mean depth, is studied using a WKBJ-type perturbation approach. Synchronous, superharmonic and in particular subharmonic resonance were selectively excited over the fast varying topography with corresponding wavelengths. For a steady current the dynamical system is autonomous and the possible nonlinear steady states and their stability were investigated. When the current has a small oscillatory component the dynamical system becomes non-autonomous, chaos is now possible.

  5. Litchi freshness rapid non-destructive evaluating method using electronic nose and non-linear dynamics stochastic resonance model.

    Science.gov (United States)

    Ying, Xiaoguo; Liu, Wei; Hui, Guohua

    2015-01-01

    In this paper, litchi freshness rapid non-destructive evaluating method using electronic nose (e-nose) and non-linear stochastic resonance (SR) was proposed. EN responses to litchi samples were continuously detected for 6 d Principal component analysis (PCA) and non-linear stochastic resonance (SR) methods were utilized to analyze EN detection data. PCA method could not totally discriminate litchi samples, while SR signal-to-noise ratio (SNR) eigen spectrum successfully discriminated all litchi samples. Litchi freshness predictive model developed using SNR eigen values shows high predictive accuracy with regression coefficients R(2) = 0 .99396.

  6. Nonlinear interactions between the pumping kinetics, fluid dynamics and optical resonator of cw fluid flow lasers. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Sentman, L.H.; Nayfeh, M.H.

    1983-12-01

    This research is an integrated theoretical and experimental investigation of the nonlinear interactions which may occur between the chemical kinetics, the fluid dynamics and the unstable resonator of a continuous wave fluid flow laser. The objectives of this grant were to measure the frequency and amplitude of the time dependent pulsations in the power spectral output which have been predicted to occur in cw chemical lasers employing unstable resonators to extract power.

  7. Off-Resonant Third-Order Optical Nonlinearity of an Ag:TiO2 Composite Film

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun-Feng; YOU Guan-Jun; DONG Zhi-Wei; LIU Ye; MA Guo-Hong; QIAN Shi-Xiong

    2005-01-01

    @@ Using the femtosecond time-resolved optical Kerr effect technique, we investigate the off-resonant nonlinear optical response of an Ag:TiO2 composite film prepared by a vacuum magnetron sputtering method. The third-order nonlinear optical susceptibility of the composite film with silver nanoparticle size of about 30 nm is estimated to be 1.9×10-10 esu at the incident laser wavelength of 800nm. When the photon energy of the incident beam is lower than that for surface plasmon or the interband transition of silver nanoparticles, the observed third-order optical nonlinearity is attributed to the intraband transition of the free electrons. Based on the linear limit of the electric field within micro-spherical model, we assign this large optical nonlinearity to the local field enhancement of the third-order nonlinearity.

  8. Controlling light with high-Q silicon photonic crystal nanocavities: Photon confinement, nonlinearity and coherence

    Science.gov (United States)

    Yang, Xiaodong

    lasing in the designed high-Q silicon photonic crystal nanocavities are proposed and numerically analyzed through the derived coupled-mode equations, with various contributions on Raman gain, optical losses, and dispersion effects. In Chapter 5, the observation of enhanced optical nonlinearities and optical bistabilities due to the two-photon-absorption induced thermo-optic effect in high-Q silicon photonic crystal nanocavities with both Lorentzian resonances and Fano resonances is presented. The experimental results highlight the ultra-low switching energy, high switching contrast, and the low threshold wavelength detuning for Fano resonances, benefiting from the sharp and asymmetric Fano lineshapes. The third topic is all-optical analogue to coherent interference phenomena in atomic systems including Fano interference and electromagnetically induced transparency (EIT). In Chapter 5, the optical analogue to Fano interference is studied in an optical system consisting of a photonic crystal nanocavity side-coupled to a waveguide with two partially reflecting elements, where the coherent interference between the discrete energy state and the continuum will give sharp and asymmetric Fano lineshapes, which can be used for low-threshold optical bistable switching with a high switching contrast. In Chapter 6, another coherent interference phenomenon called electromagnetically induced transparency (EIT) is introduced. The deterministic tuning of all-optical analogue to EIT in coherently-coupled silicon photonic crystal nanocavities is demonstrated experimentally. Through thermo-optic tuning of wavelength detuning and phase difference between these coupled nanocavities, the stepwise control of the EIT-like coherent interference is realized. The designed EIT-like optical system is analyzed well through the coupled-mode equations. These results can be used for realization of all-optical stopping of light.

  9. Optical solitons in resonant and nonresonant nonlinear media in the presence of perturbations.

    Science.gov (United States)

    Piscureanu, M; Manaila-Maximean, D

    2000-01-01

    We studied the optical solitons in nonlinear resonant and nonresonant media in the presence of perturbations, assuming that the transient effects are stimulated by the light scanning beam. We treated a slight deviation from the exact necessary condition for the soliton existence (2betanu=1), as a small perturbation for the integrable system, studying its influence upon the soliton propagation conditions. The approximation is constructed by the help of an algebraic version of the soliton perturbation theory using a Riemann boundary problem in connection with the inverse scattering method. We have obtained the soliton equation and we have solved it in the presence of a small perturbation in the adiabatic approximation. In this case we have demonstrated that for a Lorentz profile line the amplitude of the soliton remains unchanged, the only effect of the perturbation results in a phase shift.

  10. Dispersion and absorption in one-dimensional nonlinear lattices: A resonance phonon approach

    Science.gov (United States)

    Xu, Lubo; Wang, Lei

    2016-09-01

    Based on the linear response theory, we propose a resonance phonon (r-ph) approach to study the renormalized phonons in a few one-dimensional nonlinear lattices. Compared with the existing anharmonic phonon (a-ph) approach, the dispersion relations derived from this approach agree with the expectations of the effective phonon (e-ph) theory much better. The application is also largely extended, i.e., it is applicable in many extreme situations, e.g., high frequency, high temperature, etc., where the existing one can hardly work. Furthermore, two separated phonon branches (one acoustic and one optical) with a clear gap in between can be observed by the r-ph approach in a diatomic anharmonic lattice. While only one combined branch can be detected in the same lattice with both the a-ph approach and the e-ph theory.

  11. Nonlinear Container Ship Model for the Study of Parametric Roll Resonance

    DEFF Research Database (Denmark)

    Holden, Christian; Galeazzi, Roberto; Rodríguez, Claudio

    2007-01-01

    Parametric roll is a critical phenomenon for ships, whose onset may cause roll oscillations up to 40, leading to very dangerous situations and possibly capsizing. Container ships have been shown to be particularly prone to parametric roll resonance when they are sailing in moderate to heavy head...... seas. A Matlab/Simulinkr parametric roll benchmark model for a large container ship has been implemented and validated against a wide set of experimental data. The model is a part of a Matlab/Simulink Toolbox (MSS, 2007). The benchmark implements a 3rd-order nonlinear model where the dynamics of roll...... is strongly coupled with the heave and pitch dynamics. The implemented model has shown good accuracy in predicting the container ship motions, both in the vertical plane and in the transversal one. Parametric roll has been reproduced for all the data sets in which it happened, and the model provides realistic...

  12. Multidimensional resonant nonlinear spectroscopy with coherent broadband x-ray pulses

    Science.gov (United States)

    Bennett, Kochise; Zhang, Yu; Kowalewski, Markus; Hua, Weijie; Mukamel, Shaul

    2016-12-01

    New x-ray free electron laser (XFEL) and high harmonic generation (HHG) light sources are capable of generating short and intense pulses that make x-ray nonlinear spectroscopy possible. Multidimensional spectroscopic techniques, which have long been used in the nuclear magnetic resonance, infrared, and optical regimes to probe the electronic structure and nuclear dynamics of molecules by sequences of short pulses with variable delays, can thus be extended to the attosecond x-ray regime. This opens up the possibility of probing core-electronic structure and couplings, the real-time tracking of impulsively created valence-electronic wavepackets and electronic coherences, and monitoring ultrafast processes such as nonadiabatic electron-nuclear dynamics near conical-intersection crossings. We survey various possible types of multidimensional x-ray spectroscopy techniques and demonstrate the novel information they can provide about molecules.

  13. Experimental Investigation of 2:1 and 3:1 Internal Resonances in Nonlinear MEMS Arch Resonators

    KAUST Repository

    Ramini, Abdallah

    2016-12-05

    We demonstrate experimentally internal resonances in MEMS resonators. The investigation is conducted on in-plane MEMS arch resonators fabricated with a highly doped silicon. The resonators are actuated electrostatically and their stiffness are tuned by electrothermal loading by passing an electrical current though the microstructures. We show that through this tuning, the ratio of the various resonance frequencies can be varied and set at certain ratios. Particularly, we adjust the resonance frequencies of two different vibrational modes to 2:1 and 3:1. Finally, we validate the internal resonances at these ratios through frequency-response curves and FFTs.

  14. An investigation of doubly-resonant optical parametric oscillators and nonlinear crystals for squeezing

    Energy Technology Data Exchange (ETDEWEB)

    Stefszky, Michael; Buchler, Ben C; Symul, Thomas; Lam, Ping Koy [Quantum Optics Group, Department of Quantum Science, The Australian National University, ACT 0200 (Australia); Mow-Lowry, Conor M; McKenzie, Kirk; Chua, Sheon; McClelland, David E, E-mail: michael.stefszky@anu.edu.au [Centre for Gravitational Physics, Department of Quantum Science, The Australian National University, ACT 0200 (Australia)

    2011-01-14

    A squeezed light source requires properties such as high squeezing amplitude, high bandwidth and stability over time, ideally using as few resources, such as laser power, as possible. We compare three nonlinear materials, two of which have not been well characterized for squeezed state production, and also investigate the viability of doubly-resonant optical parametric oscillator cavities in achieving these requirements. A model is produced that provides a new way of looking at the construction of an optical parametric oscillator/optical parametric amplifier setup where second harmonic power is treated as a limited resource. The well-characterized periodically poled potassium titanyl phosphate (PPKTP) is compared in an essentially identical setup to two relatively new materials, periodically poled stoichiometric lithium tantalate (PPSLT) and 1.7% magnesium oxide doped periodically poled stoichiometric lithium niobate (PPSLN). Although from the literature PPSLT and PPSLN present advantages such as a higher damage threshold and a higher nonlinearity, respectively, PPKTP was still found to have the most desirable properties. With PPKTP, 5.8 dB of squeezing below the shot noise limit was achieved. With PPSLT, 5.0 dB of squeezing was observed but the power required to see this squeezing was much higher than expected. A technical problem with the PPSLN limited the observed squeezing to around 1.0 dB. This problem is discussed.

  15. Nonlinear combination parametric resonance of axially accelerating viscoelastic strings constituted by the standard linear solid model

    Institute of Scientific and Technical Information of China (English)

    LIM; C.W.

    2010-01-01

    Nonlinear combination parametric resonance is investigated for an axially accelerating viscoelastic string.The governing equation of in-planar motion of the string is established by introducing a coordinate transform in the Eulerian equation of a string with moving boundaries.The string under investigation is constituted by the standard linear solid model in which the material,not partial,time derivative was used.The governing equation leads to the Mote model for transverse vibration by omitting the longitudinal component and higher order terms.The Kirchhoff model is derived from the Mote model by replacing the tension with the averaged tension over the string.The two models are respectively analyzed via the method of multiple scales for principal parametric resonance.The amplitudes and the existence conditions of steady-state response and its stability can be numerically determined.Numerical calculations demonstrate the effects of the string material parameters,the initial tension,and the axial speed fluctuation amplitude.The outcomes of the two models are qualitatively and quantitatively compared.

  16. Non-linear magnetohydrodynamic modeling of plasma response to resonant magnetic perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Orain, F.; Bécoulet, M.; Dif-Pradalier, G.; Nardon, E.; Passeron, C.; Latu, G.; Grandgirard, V.; Fil, A.; Ratnani, A. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Huijsmans, G. [ITER Organization, Route de Vinon, F-13115 Saint-Paul-Lez-Durance (France); Pamela, S. [IIFS-PIIM. Aix Marseille Université - CNRS, 13397 Marseille Cedex20 (France); Chapman, I.; Kirk, A.; Thornton, A. [EURATOM/CCFE Fusion Association, Culham Science Centre, Oxon OX14 3DB (United Kingdom); Hoelzl, M. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching (Germany); Cahyna, P. [Association EURATOM/IPP.CR, Prague (Czech Republic)

    2013-10-15

    The interaction of static Resonant Magnetic Perturbations (RMPs) with the plasma flows is modeled in toroidal geometry, using the non-linear resistive MHD code JOREK, which includes the X-point and the scrape-off-layer. Two-fluid diamagnetic effects, the neoclassical poloidal friction and a source of toroidal rotation are introduced in the model to describe realistic plasma flows. RMP penetration is studied taking self-consistently into account the effects of these flows and the radial electric field evolution. JET-like, MAST, and ITER parameters are used in modeling. For JET-like parameters, three regimes of plasma response are found depending on the plasma resistivity and the diamagnetic rotation: at high resistivity and slow rotation, the islands generated by the RMPs at the edge resonant surfaces rotate in the ion diamagnetic direction and their size oscillates. At faster rotation, the generated islands are static and are more screened by the plasma. An intermediate regime with static islands which slightly oscillate is found at lower resistivity. In ITER simulations, the RMPs generate static islands, which forms an ergodic layer at the very edge (ψ≥0.96) characterized by lobe structures near the X-point and results in a small strike point splitting on the divertor targets. In MAST Double Null Divertor geometry, lobes are also found near the X-point and the 3D-deformation of the density and temperature profiles is observed.

  17. Non-linear magnetohydrodynamic modeling of plasma response to resonant magnetic perturbations

    Science.gov (United States)

    Orain, F.; Bécoulet, M.; Dif-Pradalier, G.; Huijsmans, G.; Pamela, S.; Nardon, E.; Passeron, C.; Latu, G.; Grandgirard, V.; Fil, A.; Ratnani, A.; Chapman, I.; Kirk, A.; Thornton, A.; Hoelzl, M.; Cahyna, P.

    2013-10-01

    The interaction of static Resonant Magnetic Perturbations (RMPs) with the plasma flows is modeled in toroidal geometry, using the non-linear resistive MHD code JOREK, which includes the X-point and the scrape-off-layer. Two-fluid diamagnetic effects, the neoclassical poloidal friction and a source of toroidal rotation are introduced in the model to describe realistic plasma flows. RMP penetration is studied taking self-consistently into account the effects of these flows and the radial electric field evolution. JET-like, MAST, and ITER parameters are used in modeling. For JET-like parameters, three regimes of plasma response are found depending on the plasma resistivity and the diamagnetic rotation: at high resistivity and slow rotation, the islands generated by the RMPs at the edge resonant surfaces rotate in the ion diamagnetic direction and their size oscillates. At faster rotation, the generated islands are static and are more screened by the plasma. An intermediate regime with static islands which slightly oscillate is found at lower resistivity. In ITER simulations, the RMPs generate static islands, which forms an ergodic layer at the very edge (ψ ≥0.96) characterized by lobe structures near the X-point and results in a small strike point splitting on the divertor targets. In MAST Double Null Divertor geometry, lobes are also found near the X-point and the 3D-deformation of the density and temperature profiles is observed.

  18. Nonlinear standing wave and acoustic streaming in an exponential-shape resonator by gas-kinetic scheme simulation

    Science.gov (United States)

    Zhang, Xiaoqing; Feng, Heying; Qu, Chengwu

    2016-10-01

    Nonlinear standing waves and acoustic streaming in an axial-symmetrical resonator with exponentially varying cross-sectional area were studied. A two-dimensional gas-kinetic Bhatnagar-Gross-Krook scheme based on the non-structure triangular grid was established to simulate nonlinear acoustic oscillations in the resonator. Details of the transient and steady flow fields and streaming were developed. The effects of winding index of the exponential-shape resonator, the displacement amplitude of the acoustic piston on the streaming, and the vortex pattern were analyzed. The results demonstrate that the acoustic streaming pattern in such resonators is different from the typical Rayleigh flow in a constant cross-sectional area resonator. No obvious shock wave appeared inside the exponential-shape resonator. The comparison reveals that with increasing the displacement amplitude of the acoustic piston energy dissipation is accompanied by vortex break-up from a first-level to a second-level transition, and even into turbulent flow. This research demonstrates that the exponential-shape resonator, especially that with a winding index of 2.2 exhibits better acoustic features and suppression effects on shock-wave, acoustic streaming, and the vortex.

  19. All-optical logical gates based on pump-induced resonant nonlinearity in an erbium-doped fiber coupler.

    Science.gov (United States)

    Li, Qiliang; Zhang, Zhen; Li, Dongqiang; Zhu, Mengyun; Tang, Xianghong; Li, Shuqin

    2014-12-01

    In this paper, we theoretically investigate all-optical logical gates based on the pump-induced resonant nonlinearity in an erbium-doped fiber coupler. The resonant nonlinearity yielded by the optical transitions between the (4)I(15/2) states and (4)I(13/2) states in Er(3+) induces the refractive index to change, which leads to switching between two output ports. First, we do a study on the switching performance, and calculate the extinction ratio (Xratio) of the device. Second, using the Xratio, we obtain the truth tables of the device. The results reveal that compared with other undoped nonlinear couplers, the erbium-doped fiber coupler can drop the switching threshold power. We also obtain different logic gates and logic operations in the cases of the same phase and different phase of two initial signals by changing the pump power.

  20. III-V semiconductor nano-resonators-a new strategy for passive, active, and nonlinear all-dielectric metamaterials

    CERN Document Server

    Liu, Sheng; Reno, John L; Sinclair, Michael B; Brener, Igal

    2016-01-01

    Metamaterials comprising assemblies of dielectric resonators have attracted much attention due to their low intrinsic loss and isotropic optical response. In particular, metasurfaces made from silicon dielectric resonators have shown desirable behaviors such as efficient nonlinear optical conversion, spectral filtering and advanced wave-front engineering. To further explore the potential of dielectric metamaterials, we present all-dielectric metamaterials fabricated from epitaxially grown III-V semiconductors that can exploit the high second-order optical susceptibilities of III-V semiconductors, as well as the ease of monolithically integrating active/gain media. Specifically, we create GaAs nano-resonators using a selective wet oxidation process that forms a low refractive index AlGaO (n~1.6) under layer similar to silicon dielectric resonators formed using silicon-on-insulator wafers. We further use the same fabrication processes to demonstrate multilayer III-V dielectric resonator arrays that provide us w...

  1. Nonlinear resonance converse magnetoelectric effect modulated by voltage for the symmetrical magnetoelectric laminates under magnetic and thermal loadings

    Science.gov (United States)

    Zhou, Hao-Miao; Liu, Hui; Zhou, Yun; Hu, Wen-Wen

    2016-12-01

    Based on the tri-layer symmetrical magnetoelectric laminates, a equivalent circuit for the nonlinear resonance converse magnetoelectric coupling effect is established. Because the nonlinear thermo-magneto-mechanical constitutive equations of magnetostrictive material were introduced, a converse magnetoelectric coefficient model was derived from the equivalent circuit, which can describe the influence of bias electric field, bias magnetic field and ambient temperature on the resonance converse magnetoelectric coupling effect. Especially, the model can well predict the modulation effect of bias electric field/voltage on the magnetism of magnetoelectric composite or the converse magnetoelectric coefficient, which is absolutely vital in applications. Both of the converse magnetoelectric coefficient and the resonance frequency predicted by the model have good agreements with the existing experimental results in qualitatively and quantitatively, and the validity of the model is confirmed. On this basis, according to the model, the nonlinear trends of the resonance converse magnetoelectric effect under different bias voltages, bias magnetic fields and ambient temperatures are predicted. From the results, it can be found that the bias voltage can effectively modulate the curve of the resonance converse magnetoelectric coefficient versus bias magnetic field, and then change the corresponding optimal bias magnetic field of the maximum converse magnetoelectric coefficient; with the increasing volume ratio of piezoelectric layers, the modulation effect of bias voltage becomes more obvious; under different bias magnetic fields, the modulation effect of bias voltage on the converse magnetoelectric effect has nonvolatility in a wide temperature region.

  2. Plasmonic Non-linear Conversion of Continuous Wave Light by Gold Nanoparticle Clusters withFluorescent Protein Loaded Gaps

    CERN Document Server

    Salakhutdinov, Ildar; Abak, Musa Kurtulus; Turkpence, Deniz; Piantanida, Luca; Fruk, Ljiljana; Tasgin, Mehmet Emre; Lazzarino, Marco; Bek, Alpan

    2014-01-01

    We propose and demonstrate a method which is feasible for deterministic activation of few molecules. Our method relies on non-linear optical excitation of few enhanced yellow fluorescent protein molecules that are sandwiched between gaps of asymmetrically constructed plasmonic gold nanoparticle clusters. We observe that as infrared photons, which cannot get absorbed by fluorescent molecules, are converted through efficient second harmonic generation activity of gold nanoparticles to visible photons, the molecules absorb them and fluoresce. Our numerical simulations demonstrate that observation of SHG with cw laser becomes possible owing to the cooperative action of conversion enhancement through Fano resonance, hybridization in the plasmon absorption spectrum and the size asymmetry of nanoparticle dimers.

  3. Derivation of the Fano profile from time-dependent density-functional theory for local thermodynamic equilibrium plasmas

    Science.gov (United States)

    Kiyokawa, Shuji

    2007-04-01

    We give the derivation of the Fano profile (the resonance energy position, the resonance width Γ , and q value) from the time-dependent nonrelativistic density-functional theory (DFT) and propose a scheme for calculating the photoabsorption cross section of hot dense plasmas. As a consequence of this derivation, we show the line profile is obtained as a superposition of Fano and Lorentz profiles when the competition of two optically allowed bound-bound and bound-free transitions occurs. We also show the results of the photoabsorption cross section by applying our scheme to an Fe plasma (density is 7.85g/cm3 , temperature is 100eV ), where the calculation is carried out without numerical divergence for any photon energy. The calculated results are in good agreement with those of Grimaldi.

  4. Universal Bound on the Fano Factor in Enzyme Kinetics

    CERN Document Server

    Barato, Andre C

    2015-01-01

    The Fano factor, an observable quantifying fluctuations of product generation by a single enzyme, can reveal information about the underlying reaction scheme. A lower bound on this Fano factor that depends on the thermodynamic affinity driving the transformation from substrate to product constrains the number of intermediate states of an enzymatic cycle. So far, this bound has been proven only for a unicyclic network of states. We show that the bound can be extended to arbitrary multicyclic networks, with the Fano factor constraining the largest value of the effective length, which is the ratio between the number of states and the number of products, among all cycles.

  5. Theory of Self-pulsing in Photonic Crystal Fano Lasers

    DEFF Research Database (Denmark)

    Rasmussen, Thorsten Svend; Yu, Yi; Mørk, Jesper

    2017-01-01

    Laser self-pulsing was a phenomenon exclusive to macroscopic lasers until recently, where self-starting laser pulsation in a microscopic photonic crystal Fano laser was reported. In this paper a theoretical model is developed to describe the Fano laser, including descriptions of the highly......-dispersive Fano mirror, the laser frequency and the threshold gain. The model is based upon a combination of conventional laser rate equations and coupled-mode theory. The dynamical model is used to demonstrate how the laser has two regimes of operation, continuous-wave output and self-pulsing, and these regimes...

  6. Raman lasing and Fano lineshapes in a packaged fiber-coupled whispering-gallerymode microresonator

    CERN Document Server

    Zhao, Guangming; Wang, Tao; Xu, Linhua; Long, Gui-lu; Yang, Lan

    2016-01-01

    We report Raman lasing and the optical analog of electromagnetically-induced-transparency (EIT) in a whispering-gallerymode (WGM) microtoroid resonator embedded in a low refractive index polymer matrix together with a tapered fiber coupler. The Raman laser supports both single and multimode operation with low power thresholds. Observations of Fano and EIT-like pheonomena in a packaged microresonator will enable high resolution sensors and can be used in networks where slow light process is needed. These results open the way for portable, robust, and stable WGM microlasers and laserbased sensors for applications in various environments.

  7. A New Approach for Studying Nonlinear Dynamic Response of a Thin Plate with Internal Resonance in a Fractional Viscoelastic Medium

    Directory of Open Access Journals (Sweden)

    Yury A. Rossikhin

    2015-01-01

    Full Text Available In the previous analysis, the dynamic behaviour of a nonlinear plate embedded into a fractional derivative viscoelastic medium has been studied by the method of multiple time scales under the conditions of the internal resonances two-to-one and one-to-one, as well as the internal combinational resonances for the case when the linear parts of nonlinear equations of motion occur to be coupled. A new approach proposed in this paper allows one to uncouple the linear parts of equations of motion of the plate, while the same method, the method of multiple time scales, has been utilized for solving nonlinear equations. The influence of viscosity on the energy exchange mechanism between interacting nonlinear modes has been analyzed. It has been shown that for some internal resonances there exist such particular cases when it is possible to obtain two first integrals, namely, the energy integral and the stream function, which allows one to reduce the problem to the calculation of elliptic integrals. The new approach enables one to solve the problems of vibrations of thin bodies more efficiently.

  8. Resonant nonlinear interactions between atmospheric waves in the polar summer mesopause region

    Institute of Scientific and Technical Information of China (English)

    LIU; Renqiang; (刘仁强); YI; Fan; (易帆)

    2003-01-01

    Data obtained from the mobile SOUSY VHF radar at And(ya/Norway in summer 1987 have been used to study the nonlinear interactions between planetary waves, tides and gravity waves in the polar mesosphere, and the instability of background atmosphere above the mesopause. It is observed that 35-h planetary wave, diurnal, semidiurnal and terdiurnal tides are the prominent perturbations in the Lomb-Scargle spectra of the zonal wind component. By inspecting the frequency combinations, several triads are identified. By bispectral analysis it is shown that most bispectral peaks stand for quadratic coupling between tidal harmonics or between tide and planetary or gravity wave, and the height dependence of bispectral peaks reflects the variation of wave-wave interactions. Above the mesopause, the occurrence heights of the maximum L-S power spectral peaks corresponding to the prominent wave components tend to increase with their frequencies. This may result from the process in which two low frequency waves interact to generate a high frequency wave. Intensities of the planetary wave and tides increase gradually, arrive at their maxima, and then decay quickly in turn with increasing height. This kind of scene correlates with a "chain" of wave-wave resonant interactions that shifts with height from lower frequency segment to higher frequency segment. By instability analysis, it is observed that above the mesopause, the Richardson number becomes smaller and smaller with height, implying that the turbulent motion grows stronger and stronger and accordingly the background atmosphere more and more instable. It is suggested that the wave-wave sum resonant interaction and the wave dissipation due to instability are two dominant dynamical processes that occur in the mesopause region. The former invokes the energy transfer from lower frequency waves to higher frequency waves. The latter results in the heating of the atmosphere and accelerating of the background flow.

  9. Birationally rigid Fano complete intersections. II

    CERN Document Server

    Pukhlikov, Aleksandr

    2011-01-01

    We prove that a generic (in the sense of Zariski topology) Fano complete intersection $V$ of the type $(d_1,...,d_k)$ in ${\\mathbb P}^{M+k}$, where $d_1+...+d_k=M+k$, is birationally superrigid if $M\\geq 7$, $M\\geq k+3$ and $\\mathop{\\rm max} \\{d_i\\}\\geq 4$. In particular, on the variety $V$ there is exactly one structure of a Mori fibre space (or a rationally connected fibre space), the groups of birational and biregular self-maps coincide, $\\mathop{\\rm Bir} V= \\mathop{\\rm Aut} V$, and the variety $V$ is non-rational. This fact covers a considerably larger range of complete intersections than the result of [J. reine angew. Math. {\\bf 541} (2001), 55-79], which required the condition $M\\geq 2k+1$. The paper is dedicated to the memory of Eckart Viehweg.

  10. SINGULAR ANALYSIS OF BIFURCATION OF NONLINEAR NORMAL MODES FOR A CLASS OF SYSTEMS WITH DUAL INTERNAL RESONANCES

    Institute of Scientific and Technical Information of China (English)

    李欣业; 陈予恕; 吴志强

    2002-01-01

    The nonlinear normal modes (NNMs) associated with integrnal resonance can be classified into two kinds: uncoupled and coupled.The bifurcation problem of the coupled NNM of systems with 1: 2: 5 dual internal resonance is in two variables.The singular analysis of it is presented after separating the two variables by taking advantage of Maple algebra, and some new bifurcation patterns are found.Different from the NNMs of systems with single internal resonance, the number of the NNMs of systems with dual internal resonance may be more or less than the number of the degrees of freedom.At last, it is pointed out that bifurcation problems in two variables can be conveniently solved by separating variables as well as using coupling equations.

  11. Nonlinear Container Ship Model for the Study of Parametric Roll Resonance

    Directory of Open Access Journals (Sweden)

    Christian Holden

    2007-10-01

    Full Text Available Parametric roll is a critical phenomenon for ships, whose onset may cause roll oscillations up to +-40 degrees, leading to very dangerous situations and possibly capsizing. Container ships have been shown to be particularly prone to parametric roll resonance when they are sailing in moderate to heavy head seas. A Matlab/Simulink parametric roll benchmark model for a large container ship has been implemented and validated against a wide set of experimental data. The model is a part of a Matlab/Simulink Toolbox (MSS, 2007. The benchmark implements a 3rd-order nonlinear model where the dynamics of roll is strongly coupled with the heave and pitch dynamics. The implemented model has shown good accuracy in predicting the container ship motions, both in the vertical plane and in the transversal one. Parametric roll has been reproduced for all the data sets in which it happened, and the model provides realistic results which are in good agreement with the model tank experiments.

  12. Nonlinear optical detection of terahertz-wave radiation from resonant tunneling diodes.

    Science.gov (United States)

    Takida, Yuma; Nawata, Kouji; Suzuki, Safumi; Asada, Masahiro; Minamide, Hiroaki

    2017-03-06

    The sensitive detection of terahertz (THz)-wave radiation from compact sources at room temperature is crucial for real-world THz-wave applications. Here, we demonstrate the nonlinear optical detection of THz-wave radiation from continuous-wave (CW) resonant tunneling diodes (RTDs) at 0.58, 0.78, and 1.14 THz. The up-conversion process in a MgO:LiNbO3 crystal under the noncollinear phase-matching condition offers efficient wavelength conversion from a THz wave to a near-infrared (NIR) wave that is detected using a commercial NIR photodetector. The minimum detection limit of CW THz-wave power is as low as 5 nW at 1.14 THz, corresponding to 2-aJ energy and 2.7 × 103 photons within the time window of a 0.31-ns pump pulse. Our results show that the input frequency and power of RTD devices can be calibrated by measuring the output wavelength and energy of up-converted waves, respectively. This optical detection technique for compact electronic THz-wave sources will open up a new opportunity for the realization of real-world THz-wave applications.

  13. Fully Nonlinear Simulations of Wave Resonance by An Array of Cylinders in Vertical Motions

    Institute of Scientific and Technical Information of China (English)

    HUANG Hao-cai; WANG Chi-zhong; LENG Jian-xing

    2013-01-01

    The finite element method (FEM) is employed to analyze the resonant oscillations of the liquid confined within multiple or an array of floating bodies with fully nonlinear boundary conditions on the free surface and the body surface in two dimensions.The velocity potentials at each time step are obtained through the FEM with 8-node quadratic shape functions.The finite element linear system is solved by the conjugate gradient (CG) method with a symmetric successive overelaxlation (SSOR) preconditioner.The waves at the open boundary are absorbed by the combination of the damping zone method and the Sommerfeld-Orlanski equation.Numerical examples are given by an array of floating wedgeshaped cylinders and rectangular cylinders.Results are provided for heave motions including wave elevations,profiles and hydrodynamic forces.Comparisons are made in several cases with the results obtained from the second order solution in the time domain.It is found that the wave amplitude in the middle region of the array is larger than those in other places,and the hydrodynamic force on a cylinder increases with the cylinder closing to the middle of the array.

  14. Resonant instability of the nonlinearly-saturated magnetorotational mode in thin Keplerian discs

    CERN Document Server

    Shtemler, Yuri M; Liverts, Edward

    2014-01-01

    The magneto-rotational decay instability (MRDI) of thin Keplerian discs threaded by poloidal magnetic fields is introduced and studied. The linear magnetohydrodynamic problem decouples into eigenvalue problems for in-plane slow- and fast- Alfv'een-Coriolis (AC), and vertical magnetosonic (MS) eigenmodes. The magnetorotational instability (MRI) is composed of a discrete number of unstable slow AC eigenmodes that is determined for each radius by the local beta. In the vicinity of the first beta threshold a parent MRI eigenmode together with a stable AC eigenmode (either slow or fast) and a stable MS eigenmode form a resonant triad. The three-wave MRDI relies on the nonlinear saturation of the parent MRI mode and the exponential growth of two daughter linearly stable waves, slow-AC and MS modes with an effective growth rate that is comparable to that of the parent MRI. If, however, the role of the AC daughter wave is played by a stable fast mode, all three modes remain bounded.

  15. A Novel All-Optical Switch in a Double-Loop Sagnac Ring Coupled with a Nonlinear Ring Resonator

    Institute of Scientific and Technical Information of China (English)

    LI Jun-Qing; LI Li; ZHAO Jia-Qun; LI Chun-Fei

    2004-01-01

    @@ We propose a novel configuration of all-optical switch based on a double-loop Sagnac ring coupled with a nonlinear ring resonator. In the case of self-phase modulation, the reducing switching threshold power down to mW is predicted, which is the improvement of earlier works on all-optical switches. The switch optimization is analysed.A way to increase the response speed of all-optical switches is suggested.

  16. Nonlinear magneto-optical rotation of frequency-modulated light resonant with a low-J transition

    CERN Document Server

    Malakyan, Y P; Budker, D; Kimball, D F; Yashchuk, V V; Malakyan, Yu. P.

    2003-01-01

    A low-light-power theory of nonlinear magneto-optical rotation of frequency-modulated light resonant with a J=1->J'=0 transition is presented. The theory is developed for a Doppler-free transition, and then modified to account for Doppler broadening and velocity mixing due to collisions. The results of the theory are shown to be in qualitative agreement with experimental data obtained for the rubidium D1 line.

  17. Modeling off-resonant nonlinear-optical cascading in mesoscopic thin films and guest-host molecular systems

    CERN Document Server

    Dawson, Nathan J; Crescimanno, Michael

    2013-01-01

    We develop a model for off-resonant microscopic cascading of scalar polarizabilities using a self-consistent field approach, and use it to study the effects of boundaries on mesoscopic systems of nonlinear polarizable atoms and molecules. We find that higher-ordered susceptibilities can be enhanced by increasing the surface-to-volume ratio through reducing the distance between boundaries perpendicular to the linear polarization. We also show lattice scaling effects on the effective nonlinear refractive indices for Gaussian beams, and illustrate finite size effects on dipole field distributions in films subject to long-wavelength propagating fields. We derive simplified expressions for the microscopic cascading of the nonlinear optical response in guest-host systems.

  18. Nonlinear resonance in Duffing oscillator with fixed and integrative time-delayed feedbacks

    Indian Academy of Sciences (India)

    V Ravichandran; V Chinnathambi; S Rajasekar

    2012-03-01

    We study the nonlinear resonance, one of the fundamental phenomena in nonlinear oscillators, in a damped and periodically-driven Duffing oscillator with two types of time-delayed feedbacks, namely, fixed and integrative. Particularly, we analyse the effect of the time-delay parameter and the strength of the time-delayed feedback. Applying the perturbation theory we obtain a nonlinear equation for the amplitude of the periodic response of the system. For a range of values of and , the response amplitude is found to be higher than that of the system in the absence of delayed feedback. The response amplitude is periodic on the parameter with period 2 / where is the angular frequency of the external periodic force. We show the occurrence of multiple branches of the response amplitude curve with and without hysteresis.

  19. Giant optical nonlinearity of silver-doped silicon thin film at low power input: laser-triggered cluster resonance

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jingsong [Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, Shanghai (China); Zhejiang University, State Key Lab of Silicon Materials, Hangzhou (China); Liu, Jing [Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, Shanghai (China); Xiao, Mufei [Universidad Nacional Autonoma de Mexico, Centro de Nanociencias y Nanotecnologia, Apartado Postal 365, Ensenada, Baja California (Mexico)

    2011-09-15

    Silver-doped silicon thin films were deposited on glass substrate in a co-sputtering procedure. Silver nanoparticles were segregatedly distributed. The nonlinear properties were extracted by z-scan measurements at low laser input power. For about 50% silver density, the nonlinear absorption and refraction coefficients peaked, respectively, at -8.086 x 10{sup -2} m/W and 1.47 x 10{sup -9} m{sup 2}/W, which, with respect to the input intensity, are several orders higher than reported data. The sudden surge of nonlinear responses was explained satisfactorily based on a self-consistent microscopic model calculation for silver clusters. Resonances exist and depend apparently on the laser-modified local cluster concentration. (orig.)

  20. Gradient nonlinearity calibration and correction for a compact, asymmetric magnetic resonance imaging gradient system

    Science.gov (United States)

    Tao, S.; Trzasko, J. D.; Gunter, J. L.; Weavers, P. T.; Shu, Y.; Huston, J., III; Lee, S. K.; Tan, E. T.; Bernstein, M. A.

    2017-01-01

    Due to engineering limitations, the spatial encoding gradient fields in conventional magnetic resonance imaging cannot be perfectly linear and always contain higher-order, nonlinear components. If ignored during image reconstruction, gradient nonlinearity (GNL) manifests as image geometric distortion. Given an estimate of the GNL field, this distortion can be corrected to a degree proportional to the accuracy of the field estimate. The GNL of a gradient system is typically characterized using a spherical harmonic polynomial model with model coefficients obtained from electromagnetic simulation. Conventional whole-body gradient systems are symmetric in design; typically, only odd-order terms up to the 5th-order are required for GNL modeling. Recently, a high-performance, asymmetric gradient system was developed, which exhibits more complex GNL that requires higher-order terms including both odd- and even-orders for accurate modeling. This work characterizes the GNL of this system using an iterative calibration method and a fiducial phantom used in ADNI (Alzheimer’s Disease Neuroimaging Initiative). The phantom was scanned at different locations inside the 26 cm diameter-spherical-volume of this gradient, and the positions of fiducials in the phantom were estimated. An iterative calibration procedure was utilized to identify the model coefficients that minimize the mean-squared-error between the true fiducial positions and the positions estimated from images corrected using these coefficients. To examine the effect of higher-order and even-order terms, this calibration was performed using spherical harmonic polynomial of different orders up to the 10th-order including even- and odd-order terms, or odd-order only. The results showed that the model coefficients of this gradient can be successfully estimated. The residual root-mean-squared-error after correction using up to the 10th-order coefficients was reduced to 0.36 mm, yielding spatial accuracy comparable to

  1. Nonlinear Oscillations and Flow of Gas Within Closed and Open Conical Resonators

    Science.gov (United States)

    Daniels, Christopher; Finkbeiner, Joshua; Steinetz, Bruce; Li, Xiaofan; Raman, Ganesh

    2004-01-01

    A dissonant acoustic resonator with a conical shaped cavity was tested in four configurations: (A) baseline resonator with closed ends and no blockage; (B) closed resonator with internal blockage; (C) ventilated resonator with no blockage; and (D) ventilated resonator with an applied pressure differential. These tests were conducted to investigate the effects of blockage and ventilation holes on dynamic pressurization. Additionally, the investigation was to determine the ability of acoustic pressurization to impede flow through the resonator. In each of the configurations studied, the entire resonator was oscillated at the gas resonant frequency while dynamic pressure, static pressure, and temperature of the fluid were measured. In the final configuration, flow through the resonator was recorded for three oscillation conditions. Ambient condition air was used as the working fluid. The baseline results showed a marked reduction in the amplitude of the dynamic pressure waveforms over previously published studies due to the use of air instead of refrigerant as the working fluid. A change in the resonant frequency was recorded when blockages of differing geometries were used in the closed resonator, while acoustic pressure amplitudes were reduced from baseline measurements. A sharp reduction in the amplitude of the acoustic pressure waves was expected and recorded when ventilation ports were added. With elevated pressure applied to one end of the resonator, flow was reduced by oscillating the cavity at the fluid fundamental resonant frequency compared to cases without oscillation and oscillation off-resonance.

  2. Analysis of Nonlinear Thermoelastic Dissipation in Euler-Bernoulli Beam Resonators.

    Science.gov (United States)

    Nourmohammadi, Zahra; Joshi, Surabhi; Vengallatore, Srikar

    2016-01-01

    The linear theory of thermoelastic damping (TED) has been extensively developed over the past eight decades, but relatively little is known about the different types of nonlinearities that are associated with this fundamental mechanism of material damping. Here, we initiate the study of a dissipative nonlinearity (also called thermomechanical nonlinearity) whose origins reside at the heart of the thermomechanical coupling that gives rise to TED. The finite difference method is used to solve the nonlinear governing equation and estimate nonlinear TED in Euler-Bernoulli beams. The maximum difference between the nonlinear and linear estimates ranges from 0.06% for quartz and 0.3% for silicon to 7% for aluminum and 28% for zinc.

  3. Fano fluctuations in superconducting-nanowire single-photon detectors

    Science.gov (United States)

    Kozorezov, A. G.; Lambert, C.; Marsili, F.; Stevens, M. J.; Verma, V. B.; Allmaras, J. P.; Shaw, M. D.; Mirin, R. P.; Nam, Sae Woo

    2017-08-01

    Because of their universal nature, Fano fluctuations are expected to influence the response of superconducting-nanowire single-photon detectors (SNSPDs). We predict that photon counting rate (P C R ) as a function of bias current (IB) in SNSPDs is described by an integral over a transverse coordinate-dependent complementary error function. Fano fluctuations in the amount of energy deposited into the electronic system contribute to the finite width of this error function Δ IB . The local response of an SNSPD can also affect this width: the location of the initial photon absorption site across the width of the wire can impact the probability of vortex-antivortex unbinding and vortex entry from the edges. In narrow-nanowire SNSPDs, the local responses are uniform, and Fano fluctuations dominate Δ IB . We demonstrate good agreement between theory and experiments for a series of bath temperatures and photon energies in narrow-wire WSi SNSPDs. In a wide-nanowire device, the strong local dependence will introduce a finite width to the P C R curve, but with sharp cusps. We show how Fano fluctuations can smooth these features to produce theoretical curves that better match experimental data. We also show that the time-resolved hotspot relaxation curves predicted by Fano fluctuations match the previously measured Lorentzian shapes (except for their tails) over the entire range of bias currents investigated experimentally.

  4. SU-E-T-347: Validation of the Condensed History Algorithm of Geant4 Using the Fano Test

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H; Mathis, M; Sawakuchi, G [The Univerity of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-01

    Purpose: To validate the condensed history algorithm and physics of the Geant4 Monte Carlo toolkit for simulations of ionization chambers (ICs). This study is the first step to validate Geant4 for calculations of photon beam quality correction factors under the presence of a strong magnetic field for magnetic resonance guided linac system applications. Methods: The electron transport and boundary crossing algorithms of Geant4 version 9.6.p02 were tested under Fano conditions using the Geant4 example/application FanoCavity. User-defined parameters of the condensed history and multiple scattering algorithms were investigated under Fano test conditions for three scattering models (physics lists): G4UrbanMscModel95 (PhysListEmStandard-option3), G4GoudsmitSaundersonMsc (PhysListEmStandard-GS), and G4WentzelVIModel/G4CoulombScattering (PhysListEmStandard-WVI). Simulations were conducted using monoenergetic photon beams, ranging from 0.5 to 7 MeV and emphasizing energies from 0.8 to 3 MeV. Results: The GS and WVI physics lists provided consistent Fano test results (within ±0.5%) for maximum step sizes under 0.01 mm at 1.25 MeV, with improved performance at 3 MeV (within ±0.25%). The option3 physics list provided consistent Fano test results (within ±0.5%) for maximum step sizes above 1 mm. Optimal parameters for the option3 physics list were 10 km maximum step size with default values for other user-defined parameters: 0.2 dRoverRange, 0.01 mm final range, 0.04 range factor, 2.5 geometrical factor, and 1 skin. Simulations using the option3 physics list were ∼70 – 100 times faster compared to GS and WVI under optimal parameters. Conclusion: This work indicated that the option3 physics list passes the Fano test within ±0.5% when using a maximum step size of 10 km for energies suitable for IC calculations in a 6 MV spectrum without extensive computational times. Optimal user-defined parameters using the option3 physics list will be used in future IC simulations to

  5. Coherent control of the Goos-Hänchen shift via Fano interference

    Science.gov (United States)

    Liu, Shaopeng; Yang, Wen-Xing; Zhu, Zhonghu

    2016-04-01

    A scheme of enhanced Goos-Hänchen (GH) shifts in reflected and transmitted light beams is exploited in a cavity, where an asymmetric double AlGaAs/GaAs quantum well structure with resonant tunneling to a common continuum is employed as the intracavity medium. With the help of Fano-type interference induced by resonant tunneling, the generated GH shifts that contain a negative lateral shift in reflected light beam and a positive lateral shift in transmitted light beam are found to be significantly enhanced. More interestingly, these GH shifts in reflected and transmitted light beams are modulated by means of a control beam and external bias voltage, in which maximum negative shift of 1.86 mm and positive shift of 0.37 mm are achievable.

  6. Nonlinear beam clean-up using resonantly enhanced sum-frequency mixing

    DEFF Research Database (Denmark)

    Karamehmedovic, Emir; Pedersen, Christian; Jensen, Ole Bjarlin;

    2009-01-01

    We investigate the possibility of improving the beam quality and obtaining high conversion efficiency in nonlinear sum-frequency generation. A 765 nm beam from an external cavity tapered diode laser is single-passed through a nonlinear crystal situated in the high intracavity field of a 1342 nm Nd...

  7. Real-time cardiovascular magnetic resonance at high temporal resolution: radial FLASH with nonlinear inverse reconstruction

    Directory of Open Access Journals (Sweden)

    Merboldt Klaus-Dietmar

    2010-07-01

    Full Text Available Abstract Background Functional assessments of the heart by dynamic cardiovascular magnetic resonance (CMR commonly rely on (i electrocardiographic (ECG gating yielding pseudo real-time cine representations, (ii balanced gradient-echo sequences referred to as steady-state free precession (SSFP, and (iii breath holding or respiratory gating. Problems may therefore be due to the need for a robust ECG signal, the occurrence of arrhythmia and beat to beat variations, technical instabilities (e.g., SSFP "banding" artefacts, and limited patient compliance and comfort. Here we describe a new approach providing true real-time CMR with image acquisition times as short as 20 to 30 ms or rates of 30 to 50 frames per second. Methods The approach relies on a previously developed real-time MR method, which combines a strongly undersampled radial FLASH CMR sequence with image reconstruction by regularized nonlinear inversion. While iterative reconstructions are currently performed offline due to limited computer speed, online monitoring during scanning is accomplished using gridding reconstructions with a sliding window at the same frame rate but with lower image quality. Results Scans of healthy young subjects were performed at 3 T without ECG gating and during free breathing. The resulting images yield T1 contrast (depending on flip angle with an opposed-phase or in-phase condition for water and fat signals (depending on echo time. They completely avoid (i susceptibility-induced artefacts due to the very short echo times, (ii radiofrequency power limitations due to excitations with flip angles of 10° or less, and (iii the risk of peripheral nerve stimulation due to the use of normal gradient switching modes. For a section thickness of 8 mm, real-time images offer a spatial resolution and total acquisition time of 1.5 mm at 30 ms and 2.0 mm at 22 ms, respectively. Conclusions Though awaiting thorough clinical evaluation, this work describes a robust and

  8. A Jacobson Radical Decomposition of the Fano-Snowflake Configuration

    CERN Document Server

    Saniga, Metod

    2008-01-01

    The Fano-Snowflake, a specific $non$-unimodular projective lattice configuration associated with the smallest ring of ternions $R_{\\diamondsuit}$ (arXiv:0803.4436 and 0806.3153), admits an interesting partitioning with respect to the Jacobson radical of $R_{\\diamondsuit}$. The totality of 21 free cyclic submodules generated by non-unimodular vectors of the free left $R_{\\diamondsuit}$-module $R_{\\diamondsuit}^{3}$ are shown to split into three disjoint sets of cardinalities 9, 9 and 3 according as the number of Jacobson radical entries in the generating vector is 2, 1 or 0, respectively. The corresponding "ternion-induced" factorization of the lines of the Fano plane sitting in the middle of the Fano-Snowflake (6 -- 7 -- 3) is found to $differ fundamentally$ from the natural one, i. e., from that with respect to the Jacobson radical of the Galois field of two elements (3 -- 3 -- 1).

  9. Twin "Fano-Snowflakes" Over the Smallest Ring of Ternions

    CERN Document Server

    Saniga, Metod; Planat, Michel; Pracna, Petr

    2008-01-01

    Given a finite associative ring with unity, $R$, any free (left) cyclic submodule (FCS) generated by a $uni$modular ($n+1$)-tuple of elements of $R$ represents a point of the $n$-dimensional projective space over $R$. Suppose that $R$ also features FCSs generated by ($n+1$)-tuples that are $not$ unimodular: what kind of geometry can be ascribed to such FCSs? Here, we (partially) answer this question for $n=2$ when $R$ is the (unique) non-commutative ring of order eight. The corresponding geometry is dubbed a "Fano-Snowflake" due to its diagrammatic appearance and the fact that it contains the Fano plane in its center. There exist, in fact, two such configurations -- each being tied to either of the two maximal ideals of the ring -- which have the Fano plane in common and can, therefore, be viewed as twins. Potential relevance of these noteworthy configurations to quantum information theory and stringy black holes is also outlined.

  10. An Experimental Study of Nonlinear Standing Waves in Resonators with Numerical Comparison

    Science.gov (United States)

    Finkbeiner, Joshua R.; Raman, Ganesh; Li, Xiaofan; Steinetz, Bruce M.; Daniels, Christopher; Huff, Dennis (Technical Monitor)

    2002-01-01

    Lawrenson et. al. [Journal of the Acoustic Society of America, Nov. 1998] described the generation of shock-free high-amplitude pressure waves in closed cavities using large equipment and resonators to produce the reported effects. An attempt is made to generate shock-free high-amplitude pressure waves using relatively small resonators. Ambient air is used as the working fluid. A small cylindrical resonator is tested resulting in the lack of a shocked waveform while a larger model of the same shape produces shock waves. A small conical resonator produces shock-free pressure waves at resonance, but the amplitude of these waves is small. A larger cone resonator model produces shock-free pressure waves of higher amplitude. A large horn-cone resonator also produces shock-free high amplitude pressure waves, A numerical model is used to compare the experimental results to theoretical results. The effects of structural resonances on the production of shock-free high-amplitude pressure waves are discussed, especially concerning difficulties encountered when these resonances were in the frequency ranges of interest. Identifying features of a structural resonance are presented.

  11. Influence of geometric and physical nonlinearities on the internal resonances of a finite continuous rod with a microstructure

    Science.gov (United States)

    Andrianov, Igor V.; Awrejcewicz, Jan; Danishevskyy, Vladyslav V.; Markert, Bernd

    2017-01-01

    In this work, nonlinear longitudinal vibrations of a finite composite rod are studied including geometric and physical nonlinearities. An original boundary value problem for a heterogeneous rod yielded by the macroscopic approximation obtained earlier by the higher-order asymptotic homogenization method is used. The effects of internal resonances and modes coupling are predicted, validated and analyzed. The defined novel continuous problem governed by PDEs is solved using space-discretization and the method of multiple time scales. We are aimed at understanding and analyzing how the presence of the microstructure influences the processes of mode interaction. It is shown that, depending on a scaling relation between the amplitude of the vibrations and the size of the unit cell, different scenarios of the modes coupling can be realized. Additionally to the asymptotic solution, numerical simulation of the modes coupling is performed by means of the Runge-Kutta fourth-order method. The obtained numerical and analytical results demonstrate good qualitative agreement.

  12. Nonlinear Transition from Mitigation to Suppression of the Edge Localized Mode with Resonant Magnetic Perturbations in the EAST Tokamak.

    Science.gov (United States)

    Sun, Y; Liang, Y; Liu, Y Q; Gu, S; Yang, X; Guo, W; Shi, T; Jia, M; Wang, L; Lyu, B; Zhou, C; Liu, A; Zang, Q; Liu, H; Chu, N; Wang, H H; Zhang, T; Qian, J; Xu, L; He, K; Chen, D; Shen, B; Gong, X; Ji, X; Wang, S; Qi, M; Song, Y; Yuan, Q; Sheng, Z; Gao, G; Fu, P; Wan, B

    2016-09-01

    Evidence of a nonlinear transition from mitigation to suppression of the edge localized mode (ELM) by using resonant magnetic perturbations (RMPs) in the EAST tokamak is presented. This is the first demonstration of ELM suppression with RMPs in slowly rotating plasmas with dominant radio-frequency wave heating. Changes of edge magnetic topology after the transition are indicated by a gradual phase shift in the plasma response field from a linear magneto hydro dynamics modeling result to a vacuum one and a sudden increase of three-dimensional particle flux to the divertor. The transition threshold depends on the spectrum of RMPs and plasma rotation as well as perturbation amplitude. This means that edge topological changes resulting from nonlinear plasma response plays a key role in the suppression of ELM with RMPs.

  13. Dynamic range enhancement of nonlinear nanomechanical resonant cantilevers for highly sensitive NEMS gas/mass sensor applications

    Science.gov (United States)

    Kacem, N.; Arcamone, J.; Perez-Murano, F.; Hentz, S.

    2010-04-01

    This paper describes a comprehensive nonlinear multiphysics model based on the Euler-Bernoulli equation that remains valid up to large displacements in the case of electrostatically actuated nanocantilevers. This purely analytical model takes into account the fringing field effects which are significant for thin resonators. Analytical simulations show very good agreement with experimental electrical measurements of silicon nanodevices using wafer-scale nanostencil lithography (nSL), monolithically integrated with CMOS circuits. Close-form expressions of the critical amplitude are provided in order to compare the dynamic ranges of NEMS cantilevers and doubly clamped beams. This model allows designers to cancel out nonlinearities by tuning some design parameters and thus gives the possibility of driving the cantilever beyond its critical amplitude. Consequently, the sensor performance can be enhanced by being optimally driven at very large amplitude, while maintaining linear behavior.

  14. Enhancement of surface plasmon resonances on the nonlinear optical properties in a GaAs quantum dot

    Science.gov (United States)

    Jiang, Xiancong; Guo, Kangxian; Liu, Guanghui; Yang, Tao; Yang, Yanlian

    2017-05-01

    In this paper, the nonlinear optical properties of a metallic nanoparticle (MNP)-semiconductor quantum dot (SQD) hybrid nanosystem with the hybrid exciton effect have been studied. Considering the influence of quantum-size effect to the dielectric function of MNP, the quantum corrected dielectric function was applied to our calculation. By using the compact-density-matrix method, the interaction between MNP and SQD has been studied theoretically. The results show that the surface plasmon resonances (SPRs) of MNP enhance indeed the nonlinear optical properties of SQD. Further more, the enhancement depends on two factors: (a) the center-to-center 7distance between MNP and SQD; (b) the radius ratio between MNP and SQD.

  15. Period doubling and non-linear resonance in the black hole candidate IGR J17091-3624 ?

    CERN Document Server

    Rebusco, P; Kluzniak, W; Abramowicz, M A

    2012-01-01

    The two high frequency quasi periodic oscillations (HFQPOs) recently reported in the black hole candidate IGR J17091-3624 by Altamirano and Belloni (2012) are in a 5:2 frequency ratio (164 Hz to 66 Hz). This ratio is strongly suggestive of period doubling and nonlinear resonance analogous to phenomena known in RV Tauri-type pulsating stars (and recently discovered also in oscillations of RR Lyrae-type and of BL Herculis-type variables). An interpretation of the frequency ratio in terms of nonlinear interactions and a comparison with the HFQPOs reported in GRS 1915+105 may imply a mass of about 6 solar masses for the black hole in IGR J17091- 3624.

  16. Interference and non-linear properties of four-wave mixing resonances in thermal vapor: analytical results and experimental verification

    CERN Document Server

    Parniak, Michał

    2014-01-01

    We develop a model to calculate non-linear polarization in a non-degenerrate four-wave mixing in diamond configuration which includes the effects of hyperfine structure and Doppler broadening. We verify it against the experiment with $5^{2}S_{1/2}$, $5^{2}P_{3/2}$, $5^{2}D_{3/2}$ and $5^{2}P_{1/2}$ levels of rubidium 85. Uncomplicated algebra enables us to express the non-linear susceptibility of a thermal ensemble in low intensity regime in terms of Voight-like profiles and conforms precisely with the experiment. The agreement is also satisfactory at high intensity and the analytical model correctly predicts the position and shape of resonances. Our intelligible results elucidate the physics of coherent interaction of light with atoms involving higher excited levels in vapors at room temperature, which is used in an increasing range of applications.

  17. Fano type transparency and other multimode interference effects in all-dielectric nanoshells

    CERN Document Server

    Garg, Srishti

    2015-01-01

    Recently, the coupling of two different modes of a homogeneous plasmonic particle and their sharply varying spectra were elucidated as Fano resonances; an 'interference' of two spatially orthogonal modes driving each other. On the other hand, the scattering (and extinction) cross-section of a non-absorbing dielectric particle is always the sum of the cross-sections of all mode numbers; and this rules out any such Fano type interference between two different mode numbers. So delectric particles exhibit an interference structure in their extinction spectra only if it manifests in the individual modes describing the scattered field of the particle. We show that in a all-dielectric core-shell particle such strong interferences in multiple mode numbers can be attained, and notably even as a spectral region of transparency and directional scattering of incident light. Here interference between the complementary normal modes of the nanoshell and core regions can be realized for each mode number, resulting in a sharp...

  18. Strain-induced kinetics of intergrain defects as the mechanism of slow dynamics in the nonlinear resonant response of humid sandstone bars

    CERN Document Server

    Vakhnenko, O O; Shankland, T J; Cate, J A T; Vakhnenko, Oleksiy O.; Vakhnenko, Vyacheslav O.; Shankland, Thomas J.; Cate, James A. Ten

    2004-01-01

    The closed description of nonlinear and slow dynamics effects exhibited by the sandstone bars in numerous resonant response experiments with the longitudinal strain configuration is proposed. Alongside with the fast subsystem of longitudinal nonlinear displacements we examine the strain dependent slow subsystem of broken intergrain and interlamina cohesive bonds and show that even the simplest but phenomenologically correct modelling of their mutual feedback elucidates the main experimental mysteries typical for the forced longitudinal oscillations of sandstone bars, namely (i) the hysteretic behaviour of resonance curve on both its slopes, (ii) the linear softening of resonant frequency with the driving level increase, and (iii) the gradual recovery (increase) of resonant frequency at low dynamical strains after the sample being conditioned by the high ones. In order to reproduce the highly nonlinear elastic features of sandstone grained structure the realistic nonperturbative form of strain potential energy...

  19. Long-distance pulse propagation on high-frequency dissipative nonlinear transmission lines/resonant tunneling diode line cascaded maps

    Energy Technology Data Exchange (ETDEWEB)

    Klofai, Yerima [Department of Physics, Higher Teacher Training College, University of Maroua, PO Box 46 Maroua (Cameroon); Essimbi, B Z [Department of Physics, Faculty of Science, University of Yaounde 1, PO Box 812 Yaounde (Cameroon); Jaeger, D, E-mail: bessimb@yahoo.fr [ZHO, Optoelectronik, Universitaet Duisburg-Essen, D-47048 Duisburg (Germany)

    2011-10-15

    Pulse propagation on high-frequency dissipative nonlinear transmission lines (NLTLs)/resonant tunneling diode line cascaded maps is investigated for long-distance propagation of short pulses. Applying perturbative analysis, we show that the dynamics of each line is reduced to an expanded Korteweg-de Vries-Burgers equation. Moreover, it is found by computer experiments that the soliton developed in NLTLs experiences an exponential amplitude decay on the one hand and an exponential amplitude growth on the other. As a result, the behavior of a pulse in special electrical networks made of concatenated pieces of lines is closely similar to the transmission of information in optical/electrical communication systems.

  20. Terahertz generation based on four-wave mixing difference frequency by resonance-enhanced third-order nonlinear of media

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shao-hua; YAO Jian-quan; ZHOU Rui; WEN Wu-qi; XU De-gang; WANG Peng

    2011-01-01

    Using nanosecond pulse near-infrared and mid-infrared laser pulses as the pump source,we obtain terahertz wave sources via four-wave difference frequency mixing.From the coupled wave theory,.we analyze the four-wave mixing process of GaSe crystal and alkali metal vapor in detail,get the analytical expression of terahertz wave output power,and discuss the conditions for achieving phase matching.By adjusting the pump frequency,the third-order nonlinear polarization of alkali metal vapor is resonance-enhanced.This program offers a new type of high-power terahertz radiation source.

  1. Microwave absorption of a TiO2@PPy hybrid and its nonlinear dielectric resonant attenuation mechanism

    Science.gov (United States)

    Jiang, Wanchun; Wang, Yu; Xie, Aming; Wu, Fan

    2016-09-01

    We report on a high-performance electromagnetic absorption material (TiO2@PPy) developed via a facile in situ polymerization process, where lower than  -60 dB maximum absorption and 6.56 dB effective absorption bandwidth (lower than  -10 dB) can be obtained under low thickness. The excellent electromagnetic wave absorption ability is attributed to the synthetic effect of improved impedance matching and the dual loss mechanism, which originates from the polarization relaxations of dipoles induced by vacancy defects and a conductive network constructed by aerogels. An equivalent circuit model is established to explicate the nonlinear dielectric resonant attenuation mechanism.

  2. Molding of plasmonic resonances in metallic nanostructures: Dependence of the non-linear electric permittivity on system size and temperature

    KAUST Repository

    Alabastri, A.

    2013-10-25

    In this paper, we review the principal theoretical models through which the dielectric function of metals can be described. Starting from the Drude assumptions for intraband transitions, we show how this model can be improved by including interband absorption and temperature effect in the damping coefficients. Electronic scattering processes are described and included in the dielectric function, showing their role in determining plasmon lifetime at resonance. Relationships among permittivity, electric conductivity and refractive index are examined. Finally, a temperature dependent permittivity model is presented and is employed to predict temperature and non-linear field intensity dependence on commonly used plasmonic geometries, such as nanospheres. 2013 by the authors; licensee MDPI, Basel, Switzerland.

  3. Nonlinear Dynamics and Bifurcation Behavior of a 2-DOF Spring Resonator with End Stopper for Energy Harvesting

    Directory of Open Access Journals (Sweden)

    El Aroudi A.

    2014-01-01

    Full Text Available In this paper, the model of a two-degree-of-freedom (2-DOF spring resonator with end stopper for an energy harvesting application is presented. Then we characterize its nonlinear dynamical behavior by numerical simulations when some suitable parameters are varied. The system is formed by two resonators subject to external vibrational excitation and with an end stopper. We present the continuous time dynamical model of the system in the form of a switched fourth order differential equation. Harmonic vibrations are considered as the main ambient energy source for the system and its frequency response representing the RMS value of the displacement is first computed. The dynamical behavior is unveiled by computing state-space trajectories, timedomain series and FFT spectra and frequency response as the excitation amplitude is varied.

  4. Near-resonant second-order nonlinear susceptibility in c-axis oriented ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Weiwei; Wang, Kai; Long, Hua; Wang, Bing, E-mail: wangbing@hust.edu.cn; Lu, Peixiang, E-mail: lupeixiang@hust.edu.cn [Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Chu, Sheng [School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

    2014-08-18

    Near-resonant second-harmonic generation (SHG) in c-axis oriented ZnO nanorods is studied under the femtosecond laser with wavelength from 780 nm to 810 nm. A highly efficient SHG is obtained, which is attributed to the d{sub 131} component of the second-order nonlinear susceptibility. The largest d{sub 131} value is estimated to be 10.2 pm/V at the pumping wavelength of 800 nm, which indicates a large SHG response of the c-axis oriented ZnO nanorods in the near-resonant region. Theoretical calculation based on finite-difference time-domain simulation suggests a four-fold local-field enhancement of the SHG.

  5. Resonant field enhancement in periodically arranged microslits for non-linear terahertz spectroscopy

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Iwaszczuk, Krzysztof; Zalkovskij, Maksim;

    We present a design of periodically arranged microslits in a gold film for nonlinear terahertz phonon spectroscopy.Global optimization of array parameters gives a field enhancement of more than 50, due to plasmonic coupling between individual slits....

  6. Impact of third-order dispersion on nonlinear bifurcations in optical resonators

    Energy Technology Data Exchange (ETDEWEB)

    Leo, François [Service OPERA-photonique, Université libre de Bruxelles (ULB), 50 Avenue F.D. Roosevelt, CP 194/5, B-1050 Bruxelles (Belgium); Photonics Research Group, Department of Information Technology, Ghent University–IMEC, Ghent B-9000 (Belgium); Coen, Stéphane [Department of Physics, c, Private Bag, 92019, Auckland (New Zealand); Kockaert, Pascal; Emplit, Philippe; Haelterman, Marc [Service OPERA-photonique, Université libre de Bruxelles (ULB), 50 Avenue F.D. Roosevelt, CP 194/5, B-1050 Bruxelles (Belgium); Mussot, Arnaud [PhLAM, Université de Lille 1, Bât. P5-bis, UMR CNRS/USTL 8523, F-59655 Villeneuve d' Ascq (France); Taki, Majid, E-mail: abdelmajid.taki@univ-lille1.fr [PhLAM, Université de Lille 1, Bât. P5-bis, UMR CNRS/USTL 8523, F-59655 Villeneuve d' Ascq (France)

    2015-09-18

    It is analytically shown that symmetry breaking, in dissipative systems, affects the nature of the bifurcation at onset of instability resulting in transitions from super to subcritical bifurcations. In the case of a nonlinear fiber cavity, we have derived an amplitude equation to describe the nonlinear dynamics above threshold. An analytical expression of the critical transition curve is obtained and the predictions are in excellent agreement with the numerical solutions of the full dynamical model.

  7. Strong field enhancement and light-matter interactions with all-dielectric metamaterials based on split bar resonators.

    Science.gov (United States)

    Zhang, Jianfa; Liu, Wei; Zhu, Zhihong; Yuan, Xiaodong; Qin, Shiqiao

    2014-12-15

    Strong subwavelength field enhancement has often been assumed to be unique to plasmonic nanostructures. Here we propose a type of all-dielectric metamaterials based on split bar resonators. The nano gap at the centre of the resonant elements results in large local field enhancement and light localization in the surrounding medium, which can be employed for strong light-matter interactions. In a Fano-resonant dielectric metamaterial comprising pairs of asymmetric split silicon bars, the enhancement of electric field amplitude in the gap exceeds 120 while the averaged electromagnetic energy density is enhanced by more than 7000 times. An optical refractive index sensor with a potential sensitivity of 525 nm/RIU is designed based on the proposed metamaterials. The proposed concept can be applied to other types of dielectric nanostructures and may stimulate further research of dielectric metamaterials for applications ranging from nonlinear optics and sensing to the realization of new types of active lasing devices.

  8. Dynamical Phenomena in an Optical-Wavelength Phonon Laser (Phaser): Nonlinear Resonances and Self-Organized Mode Alternation

    CERN Document Server

    Makovetskii, D N

    2011-01-01

    This is a part of an overview of my early studies on nonlinear spin-phonon dynamics in solid state optical-wavelength phonon lasers (phasers) started in 1984. The main goal of this work is a short description and a qualitative analysis of experimental data on low-frequency nonlinear resonances revealed in a nonautonomous ruby phaser. Under phaser pumping modulation near these resonances, an unusual kind of self-organized motions in the ruby spin-phonon system was observed by me in 1984 for the first time. The original technique of optical-wavelength microwave-frequency acoustic stimulated emission (SE) detection and microwave-frequency power spectra (MFPS) analysis was used in these experiments (description of the technique see: D.N.Makovetskii, Cand. Sci. Diss., Kharkov, 1983). The real time evolution of MFPS was studied using this technique at scales up to several hours. The phenomenon of the self-organized periodic alternation of SE phonon modes was experimentally revealed at hyperlow frequencies from abou...

  9. Analytic variance estimates of Swank and Fano factors.

    Science.gov (United States)

    Gutierrez, Benjamin; Badano, Aldo; Samuelson, Frank

    2014-07-01

    Variance estimates for detector energy resolution metrics can be used as stopping criteria in Monte Carlo simulations for the purpose of ensuring a small uncertainty of those metrics and for the design of variance reduction techniques. The authors derive an estimate for the variance of two energy resolution metrics, the Swank factor and the Fano factor, in terms of statistical moments that can be accumulated without significant computational overhead. The authors examine the accuracy of these two estimators and demonstrate how the estimates of the coefficient of variation of the Swank and Fano factors behave with data from a Monte Carlo simulation of an indirect x-ray imaging detector. The authors' analyses suggest that the accuracy of their variance estimators is appropriate for estimating the actual variances of the Swank and Fano factors for a variety of distributions of detector outputs. The variance estimators derived in this work provide a computationally convenient way to estimate the error or coefficient of variation of the Swank and Fano factors during Monte Carlo simulations of radiation imaging systems.

  10. Analytic variance estimates of Swank and Fano factors

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, Benjamin; Badano, Aldo; Samuelson, Frank, E-mail: frank.samuelson@fda.hhs.gov [US Food and Drug Administration, Silver Spring, Maryland 20993 (United States)

    2014-07-15

    Purpose: Variance estimates for detector energy resolution metrics can be used as stopping criteria in Monte Carlo simulations for the purpose of ensuring a small uncertainty of those metrics and for the design of variance reduction techniques. Methods: The authors derive an estimate for the variance of two energy resolution metrics, the Swank factor and the Fano factor, in terms of statistical moments that can be accumulated without significant computational overhead. The authors examine the accuracy of these two estimators and demonstrate how the estimates of the coefficient of variation of the Swank and Fano factors behave with data from a Monte Carlo simulation of an indirect x-ray imaging detector. Results: The authors' analyses suggest that the accuracy of their variance estimators is appropriate for estimating the actual variances of the Swank and Fano factors for a variety of distributions of detector outputs. Conclusions: The variance estimators derived in this work provide a computationally convenient way to estimate the error or coefficient of variation of the Swank and Fano factors during Monte Carlo simulations of radiation imaging systems.

  11. Bidirectional Fano Algorithm for Lattice Coded MIMO Channels

    KAUST Repository

    Al-Quwaiee, Hessa

    2013-05-08

    Recently, lattices - a mathematical representation of infinite discrete points in the Euclidean space, have become an effective way to describe and analyze communication systems especially system those that can be modeled as linear Gaussian vector channel model. Channel codes based on lattices are preferred due to three facts: lattice codes have simple structure, the code can achieve the limits of the channel, and they can be decoded efficiently using lattice decoders which can be considered as the Closest Lattice Point Search (CLPS). Since the time lattice codes were introduced to Multiple Input Multiple Output (MIMO) channel, Sphere Decoder (SD) has been an efficient way to implement lattice decoders. Sphere decoder offers the optimal performance at the expense of high decoding complexity especially for low signal-to-noise ratios (SNR) and for high- dimensional systems. On the other hand, linear and non-linear receivers, Minimum Mean Square Error (MMSE), and MMSE Decision-Feedback Equalization (DFE), provide the lowest decoding complexity but unfortunately with poor performance. Several studies works have been conducted in the last years to address the problem of designing low complexity decoders for the MIMO channel that can achieve near optimal performance. It was found that sequential decoders using backward tree 
search can bridge the gap between SD and MMSE. The sequential decoder provides an interesting performance-complexity trade-off using a bias term. Yet, the sequential decoder still suffers from high complexity for mid-to-high SNR values. In this work, we propose a new algorithm for Bidirectional Fano sequential Decoder (BFD) in order to reduce the mid-to-high SNR complexity. Our algorithm consists of first constructing a unidirectional Sequential Decoder based on forward search using the QL decomposition. After that, BFD incorporates two searches, forward and backward, to work simultaneously till they merge and find the closest lattice point to the

  12. Nonlinear optical sub-bandgap excitation of ZnO-based photonic resonators

    Energy Technology Data Exchange (ETDEWEB)

    Bader, Christina A.; Zeuner, Franziska; Bader, Manuel H. W.; Zentgraf, Thomas; Meier, Cedrik [Department of Physics and Center for Optoelectronics and Photonics Paderborn (CeOPP), Universität Paderborn, Warburger Str. 100, 33098 Paderborn (Germany)

    2015-12-07

    Zinc oxide (ZnO) is a versatile candidate for photonic devices due to its highly efficient optical emission. However, for pumping of ZnO photonic devices UV-sources are required. Here, we investigate the alternative usage of widely available pulsed near-infrared (NIR)-sources and compare the efficiency of linear and nonlinear excitation processes. We found that bulk ZnO, ZnO thin films grown by molecular beam epitaxy, and ZnO/SiO{sub 2} microdisk devices exhibit strong nonlinear response when excited with NIR pulses (λ ≈ 1060 nm). In addition, we show that the ZnO/SiO{sub 2} microdisks exhibit sharp whispering gallery modes over the blue-yellow part of the visible spectrum for both excitation conditions and high Q-factors up to Q = 4700. The results demonstrate that nonlinear excitation is an efficient way to pump ZnO photonic devices.

  13. Direct observation of nonlinear coupling in wave turbulence at the surface of water and relevance of approximate resonances

    Science.gov (United States)

    Aubourg, Quentin; Mordant, Nicolas

    2016-04-01

    The theoretical framework of Weak Turbulence describes the statistical properties of a large collection of nonlinear waves. For a weakly nonlinear wave field, energy is assumed to be transferred only trough resonant interaction. This enables the computation of analytical solutions of the stationary statistical states (Zakhaorv spectrum). Some similarities with hydrodynamical turbulence appear : an energy cascade is present from the injection scale to the dissipation at small scales. The theory has been applied to numerous systems many of them being of geophysical or astrophysical nature (water surface waves, internal waves, inertial waves, solar winds) as well as superfluid turbulence, lasers, nonlinear optics in fibers or vibrated elastic plates. For water surface waves, experimental laboratory measurements often fail to reproduce quantitatively theoretical predictions. Gravity waves and capillary waves are often treated separately because of their different nature. For capillary waves, energy is supposed to be transferred trough 3-waves interactions, whereas for gravity waves the coupling involves 4 waves (because of the curvature of the dispersion relation which does not allow triadic solutions). In the laboratory, the range of exited wavelength are usually not strongly separated from the crossover between capillary and gravity waves (which occur near 13 Hz) due to size or measurement limitations. Near this crossover, the dispersion relation is significantly affected and this impacts most likely the theoretical predictions. To investigate how this special point may act on the phenomenology, we report laboratory experiments on gravity-capillary waves focused on the crossover (Aubourg,Mordant-PRL,2015). The setup consists in a 70 ∗ 40 cm2 vessel where waves are generated by horizontal vibration. A Fourier Transform Profilometry technique is used that is fully resolved in time and space and thus permits to compute the full space-time spectrum. The presence of an

  14. 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.

  15. Plasmonic Moon: a Fano-like approach for squeezing the magnetic field in the infrared

    KAUST Repository

    Panaro, Simone

    2015-08-11

    Outstanding results have been achieved in the localization of optical electric fields via ultrasmall plasmonic cavities, paving the way to the subdiffractive confinement of local electromagnetic fields. However, due to the intrinsic constraints related to conventional architectures, no comparable squeezing factors have been managed yet for the magnetic counterpart of radiation, practically hindering the detection and manipulation of magneto-optical effects at the nanoscale. Here, we observe a strong magnetic field nanofocusing in the infrared, promoted by the induction of a coil-type Fano resonance. By triggering the coil current via a quadrupole-like plasmonic mode, we straightforwardly boost the enhancement of the infrared magnetic field and perform its efficient squeezing in localized nanovolumes.

  16. Resonance Rayleigh scattering and resonance non-linear scattering method for the determination of aminoglycoside antibiotics with water solubility CdS quantum dots as probe

    Science.gov (United States)

    Liu, Zhengwen; Liu, Shaopu; Wang, Lei; Peng, Juanjuan; He, Youqiu

    2009-09-01

    In pH 6.6 Britton-Robinson buffer medium, the CdS quantum dots capped by thioglycolic acid could react with aminoglycoside (AGs) antibiotics such as neomycin sulfate (NEO) and streptomycin sulfate (STP) to form the large aggregates by virtue of electrostatic attraction and the hydrophobic force, which resulted in a great enhancement of resonance Rayleigh scattering (RRS) and resonance non-linear scattering such as second-order scattering (SOS) and frequency doubling scattering (FDS). The maximum scattering peak was located at 310 nm for RRS, 568 nm for SOS and 390 nm for FDS, respectively. The enhancements of scattering intensity (Δ I) were directly proportional to the concentration of AGs in a certain ranges. A new method for the determination of trace NEO and STP using CdS quantum dots probe was developed. The detection limits (3 σ) were 1.7 ng mL -1 (NEO) and 4.4 ng mL -1 (STP) by RRS method, were 5.2 ng mL -1 (NEO) and 20.9 ng mL -1 (STP) by SOS method and were 4.4 ng mL -1 (NEO) and 25.7 ng mL -1 (STP) by FDS method, respectively. The sensitivity of RRS method was the highest. The optimum conditions and influence factors were investigated. In addition, the reaction mechanism was discussed.

  17. Analysis of contributions of nonlinear material constants to temperature-induced velocity shifts of quartz surface acoustic wave resonators.

    Science.gov (United States)

    Zhang, Haifeng; Kosinski, John A; Zuo, Lei

    2016-09-01

    In this paper, we examine the significance of the various higher-order effects regarding calculating temperature behavior from a set of material constants and their temperature coefficients. Temperature-induced velocity shifts have been calculated for quartz surface acoustic wave (SAW) resonators and the contributions of different groups of nonlinear material constants (third-order elastic constants (TOE), third-order piezoelectric constants (TOP), third-order dielectric constants (TOD) and electrostrictive constants (EL)) to the temperature-induced velocity shifts have been analyzed. The analytical methodology has been verified through the comparison of experimental and analytical results for quartz resonators. In general, the third-order elastic constants were found to contribute most significantly to the temperature-induced shifts in the SAW velocity. The contributions from the third-order dielectric constants and electrostrictive constants were found to be negligible. For some specific cases, the third-order piezoelectric constants were found to make a significant contribution to the temperature-induced shifts. The significance of each third-order elastic constant as a contributor to the temperature-velocity effect was analyzed by applying a 10% variation to each of the third-order elastic constants separately. Additionally, we have considered the issues arising from the commonly used thermoelastic expansions that provide a good but not exact description of the temperature effects on frequency in piezoelectric resonators as these commonly used expansions do not include the effects of higher-order material constants.

  18. An investigation of doubly-resonant optical parametric oscillators and nonlinear crystals for squeezing

    NARCIS (Netherlands)

    Stefszky, Michael; Mow-Lowry, Conor M.; McKenzie, Kirk; Chua, Sheon; Buchler, Ben C.; Symul, Thomas; McClelland, David E.; Lam, Ping Koy

    2011-01-01

    A squeezed light source requires properties such as high squeezing amplitude, high bandwidth and stability over time, ideally using as few resources, such as laser power, as possible. We compare three nonlinear materials, two of which have not been well characterized for squeezed state production,

  19. An investigation of doubly-resonant optical parametric oscillators and nonlinear crystals for squeezing

    NARCIS (Netherlands)

    Stefszky, Michael; Mow-Lowry, Conor M.; McKenzie, Kirk; Chua, Sheon; Buchler, Ben C.; Symul, Thomas; McClelland, David E.; Lam, Ping Koy

    2011-01-01

    A squeezed light source requires properties such as high squeezing amplitude, high bandwidth and stability over time, ideally using as few resources, such as laser power, as possible. We compare three nonlinear materials, two of which have not been well characterized for squeezed state production, a

  20. Lineshape Engineering in an All-Pass Ring Resonator with Backreflection Coupled to a Symmetrical Fabry-Perot Resonator

    KAUST Repository

    Melnikov, Vasily

    2012-11-10

    We derive transfer functions for an all-pass ring resonator with internal backreflection coupled to a symmetrical Fabry-Perot resonator and demonstrate electromagnetically induced transparency-like and Fano-like lineshapes tunable by backreflection in the ring resonator.

  1. Nonlinear Phenomena and Resonant Parametric Perturbation Control in QR-ZCS Buck DC-DC Converters

    Science.gov (United States)

    Hsieh, Fei-Hu; Liu, Feng-Shao; Hsieh, Hui-Chang

    The purpose of this study is to investigate the chaotic phenomena and to control in current-mode controlled quasi-resonant zero-current-switching (QR-ZCS) DC-DC buck converters, and to present control of chaos by resonant parametric perturbation control methods. First of all, MATLAB/SIMULINK is used to derive a mathematical model for QR-ZCS DC-DC buck converters, and to simulate the converters to observe the waveform of output voltages, inductance currents and phase-plane portraits from the period-doubling bifurcation to chaos by changing the load resistances. Secondly, using resonant parametric perturbation control in QR-ZCS buck DC-DC converters, the simulation results of the chaotic converter form chaos state turn into stable state period 1, and improve ripple amplitudes of converters under the chaos, to verify the validity of the proposes method.

  2. NONLINEAR OPTICS: Stimulated resonant hyper-Raman scattering of light by polaritons in alkali metal vapors

    Science.gov (United States)

    Galaĭchuk, Yu A.; Yashkir, Yu N.

    1989-12-01

    A theory is developed for the calculation of the gain g due to stimulated resonant hyper-Raman scattering of light by polaritons in gaseous media. It is shown that throughout the tuning range of the pump frequency (including one- and two-photon resonances) a maximum of g corresponds to a dispersion curve of polaritons plotted ignoring attenuation. Theoretical results are used to analyze characteristics of hyper-Raman scattering in sodium vapor. It is shown that under normal experimental conditions the splitting of polariton branches is considerable (amounting to tens of reciprocal centimeters on the frequency scale and several angular degrees). The value of g is estimated for two-photon resonances in the case when the pump frequency is tunable in a wide range. The optimal conditions for stimulated hyper-Raman scattering are identified.

  3. Nonlinear optical processes at quadrupole polariton resonance in Cu2O as probed by a Z-scan technique

    Science.gov (United States)

    Mani, S.; Jang, J. I.; Ketterson, J. B.

    2010-09-01

    Employing a modified Z-scan technique at 2 K, we monitor not only the fundamental (ω) but also the frequency-doubled (2ω) and tripled (3ω) Z-scan responses in Cu2O when the input laser frequency ω is tuned to the two-photon quadrupole polariton resonance. The Z-scan response at ω allows us to accurately estimate the absolute number of polaritons generated via two-photon absorption. A striking dip is observed near the 2ω Z-scan focus which basically arises from Auger-type recombination of polaritons. Under high excitation levels, the 3ω Z-scan shows strong third harmonic generation. Based on the nonlinear optical parameters determined, we estimate the experimental polariton density achievable and propose a direction for polariton-based Bose-Einstein condensation in Cu2O .

  4. Nonlinear coil sensitivity estimation for parallel magnetic resonance imaging using data-adaptive steering kernel regression method.

    Science.gov (United States)

    Fang, Sheng; Guo, Hua

    2013-01-01

    The parallel magnetic resonance imaging (parallel imaging) technique reduces the MR data acquisition time by using multiple receiver coils. Coil sensitivity estimation is critical for the performance of parallel imaging reconstruction. Currently, most coil sensitivity estimation methods are based on linear interpolation techniques. Such methods may result in Gibbs-ringing artifact or resolution loss, when the resolution of coil sensitivity data is limited. To solve the problem, we proposed a nonlinear coil sensitivity estimation method based on steering kernel regression, which performs a local gradient guided interpolation to the coil sensitivity. The in vivo experimental results demonstrate that this method can effectively suppress Gibbs ringing artifact in coil sensitivity and reduces both noise and residual aliasing artifact level in SENSE reconstruction.

  5. Nonlinear Response of Vibrational Conveyers with Nonideal Vibration Exciter: Superharmonic and Subharmonic Resonance

    Directory of Open Access Journals (Sweden)

    H. Bayıroğlu

    2012-01-01

    Full Text Available Vibrational conveyers with a centrifugal vibration exciter transmit their load based on the jumping method. Common unbalanced-mass driver oscillates the trough. The motion is strictly related to the vibrational parameters. The transition over resonance of a vibratory system, excited by rotating unbalances, is important in terms of the maximum vibrational amplitude produced and the power demand on the drive for the crossover. The mechanical system is driven by the DC motor. In this study, the working ranges of oscillating shaking conveyers with nonideal vibration exciter have been analyzed analytically for superharmonic and subharmonic resonances by the method of multiple scales and numerically. The analytical results obtained in this study agree well with the numerical results.

  6. Coherent two-dimensional spectroscopy of a Fano model

    CERN Document Server

    Poulsen, Felipe; Pullerits, Tõnu; Hansen, Thorsten

    2016-01-01

    The Fano lineshape arises from the interference of two excitation pathways to reach a continuum. Its generality has resulted in a tremendous success in explaining the lineshapes of many one-dimensional spectroscopies - absorption, emission, scattering, conductance, photofragmentation - applied to very varied systems - atoms, molecules, semiconductors and metals. Unravelling a spectroscopy into a second dimension reveals the relationship between states in addition to decongesting the spectra. Femtosecond-resolved two-dimensional electronic spectroscopy (2DES) is a four-wave mixing technique that measures the time-evolution of the populations, and coherences of excited states. It has been applied extensively to the dynamics of photosynthetic units, and more recently to materials with extended band-structures. In this letter, we solve the full time-dependent third-order response, measured in 2DES, of a Fano model and give the new system parameters that become accessible.

  7. Fano factor evaluation of diamond detectors for alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Shimaoka, Takehiro; Kaneko, Junichi H.; Tsubota, Masakatsu; Shimmyo, Hiroaki [Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido, 060-8628 (Japan); Sato, Yuki [Naraha Remote Technology Development Center, Japan Atomic Energy Agency, Naraha-machi, Futaba-gun, Fukushima, 979-0513 (Japan); Chayahara, Akiyoshi; Umezawa, Hitoshi; Mokuno, Yoshiaki [Advanced Power Electronics Research Center, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka, 563-8577 (Japan); Watanabe, Hideyuki [Research Institute for Electronics and Photonics, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, 305-8565 (Japan)

    2016-10-15

    This report is the first describing experimental evaluation of Fano factor for diamond detectors. High-quality self-standing chemical vapor deposited diamond samples were produced using lift-off method. Alpha-particle induced charge measurements were taken for three samples. A 13.1 ±0.07 eV of the average electron-hole pair creation energy and excellent energy resolution of approximately 0.3% were found for 5.486 MeV alpha particles from an {sup 241}Am radioactive source. The best Fano factor for 5.486 MeV alpha particles, calculated from experimentally obtained epsilon values and the detector intrinsic energy resolution, was 0.382 ± 0.007. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Non-linear resonances in the forced responses of plates. I - Symmetric responses of circular plates

    Science.gov (United States)

    Sridhar, S.; Mook, D. T.; Nayfeh, A. H.

    1975-01-01

    The dynamic analogue of the von Karman equations is used to study the symmetric response of a circular plate to a harmonic excitation when the frequency of the excitation is near one of the natural frequencies. It is shown that, in general, when there is no internal resonance (i.e., the natural frequencies are not commensurable), only the mode having a frequency near that of the excitation is strongly excited (i.e., is needed to represent the response in the first approximation). A clamped, circular plate is used as a numerical example to show that, when there is an internal resonance, more than one of the modes involved in this resonance can be strongly excited; moreover, when more than one mode is strongly excited, the lower modes can dominate the response, even when the frequency of the excitation is near that of the highest mode. This possibility was not revealed by any of the earlier studies which were based on the same governing equations.

  9. Comment on "An approximate transfer function for the dual-resonance nonlinear filter model of auditory frequency selectivity" [J. Acoust. Soc. Am. 114, 2112-21171 (L)

    NARCIS (Netherlands)

    Duifhuis, H

    This letter concerns the paper "An approximate transfer function for the dual-resonance nonlinear filter model of auditory frequency selectivity" [E. A. Lopez-Poveda, J. Acoust. Soc. Am. 114, 2112-2117 (2003)]. It proposes a correction of the historical framework in which the paper is presented.

  10. Resonances of a nonlinear single-degree-of-freedom system with time delay in linear feedback control

    Energy Technology Data Exchange (ETDEWEB)

    El-Bassiouny, Atef F. [Mathematics Dept., Benha Univ., Benha (Egypt); El-Kholy, Salah [Dept. of Mathematics, Menoufia Univ., Shebin El-kom (Egypt)

    2010-05-15

    The primary and subharmonic resonances of a nonlinear single-degree-of-freedom system under feedback control with a time delay are studied by means of an asymptotic perturbation technique. Both external (forcing) and parametric excitations are included. By means of the averaging method and multiple scales method, two slow-flow equations for the amplitude and phase of the primary and subharmonic resonances and all other parameters are obtained. The steady state (fixed points) corresponding to a periodic motion of the starting system is investigated and frequency-response curves are shown. The stability of the fixed points is examined using the variational method. The effect of the feedback gains, the time-delay, the coefficient of cubic term, and the coefficients of external and parametric excitations on the steady-state responses are investigated and the results are presented as plots of the steady-state response amplitude versus the detuning parameter. The results obtained by two methods are in excellent agreement. (orig.)

  11. How to Determine Experimentally the Fano Factor in DROIDs

    Science.gov (United States)

    Samedov, Victor V.

    2009-12-01

    The method of experimental determination of the Fano factor in superconducting materials is based on usage of two sensor signals of a distributed readout imaging detector (DROID). In detector of this type a photon is absorbed in a superconducting layer with two superconducting tunnel junctions (STJs) at the ends. In this work it is shown, that the correlation between the two STJ signals depends on the fundamental combination of the Fano factor and the effective energy of quasiparticle formation in the superconducting material of DROID. The suggested formula for this fundamental combination depends on the energy of a primary particle, on the mean values of STJs' signal amplitudes, and on the variances of the sum and the difference of the STJs' signals. As this fundamental combination depends on the energy of a primary particle and on the particle interaction point, then it should depend on the local physical properties of the absorber. Independent determination of the effective energy of quasiparticle formation allows one to determine the value of the Fano factor. The important advantage of proposed method is its independence from the STJs' electronic gains and noise.

  12. Vibration reduction on a nonlinear flexible structure through resonant control and disturbance estimator

    Science.gov (United States)

    Cazzulani, Gabriele; Resta, Ferruccio; Ripamonti, Francesco

    2012-04-01

    Large mechanical structures are often affected by high level vibrations due to their flexibility. These vibrations can reduce the system performances and lifetime and the use of active vibration control strategies becomes very attractive. In this paper a combination of resonant control and a disturbance estimator is proposed. This solution is able to improve the system performances during the transient motion and also to reject the disturbance forces acting on the system. Both control logics are based on a modal approach, since it allows to describe the structure dynamics considering only few degrees of freedom.

  13. Carbon nanotubes as electromechanical resonators: Single-electron tunneling, nonlinearity, and high-bandwidth readout

    OpenAIRE

    Meerwaldt, H. B.

    2013-01-01

    A carbon nanotube (CNT) is a remarkable material and can be thought of as a single-atom thick cylinder of carbon atoms capped of with a semisphere. This is called a single-walled CNT and, depending on how the cylinder is rolled up, CNTs are either semiconducting or metallic. A CNT is made into a mechanical resonator by suspending it between two electrodes. The CNT is driven into motion electrostatically, and the mechanical motion is detected using the current flowing through the CNT. We use t...

  14. An improved exponential filter for fast nonlinear registration of brain magnetic resonance images

    Institute of Scientific and Technical Information of China (English)

    Zhiying Long; Li Yao; Kewei Chen; Danling Peng

    2009-01-01

    A linear elastic convolution filter was derived from the eigenfunctions of the Navier-Stokes differential operator by Bro-Nielsen in order to match images with large deformations. Due to the complexity of constructing the elastic convolution filter, the algorithm's effi-ciency reduces rapidly with the increase in the image's size. In our previous work, a simple two-sided exponential filter with high efficiency was proposed to approximate an elastic filter. However, its poor smoothness may degenerate the performance. In this paper, a new expo-nential filter was constructed by utilizing a modified nonlinear curve fitting method to approximate the elastic filter. The new filter's good smoothness makes its performance comparable to an elastic filter. Its simple and separable form makes the algorithm's speed faster than the elastic filter. Furthermore, our experiments demonstrated that the new filter was suitable for both the elastic and fluid models.

  15. Principal resonance response of a stochastic elastic impact oscillator under nonlinear delayed state feedback

    Institute of Scientific and Technical Information of China (English)

    黄冬梅; 徐伟; 谢文贤; 韩群

    2015-01-01

    In this paper, the principal resonance response of a stochastically driven elastic impact (EI) system with time-delayed cubic velocity feedback is investigated. Firstly, based on the method of multiple scales, the steady-state response and its dynamic stability are analyzed in deterministic and stochastic cases, respectively. It is shown that for the case of the multi-valued response with the frequency island phenomenon, only the smallest amplitude of the steady-state response is stable under a certain time delay, which is different from the case of the traditional frequency response. Then, a design criterion is proposed to suppress the jump phenomenon, which is induced by the saddle-node bifurcation. The effects of the feedback parameters on the steady-state responses, as well as the size, shape, and location of stability regions are studied. Results show that the system responses and the stability boundaries are highly dependent on these parameters. Furthermore, with the purpose of suppressing the amplitude peak and governing the resonance stability, appropriate feedback gain and time delay are derived.

  16. Photoinduced processes and resonant third-order nonlinearity in poly (3-dodecylthiophene) studied by femtosecond time resolved degenerate four wave mixing

    Science.gov (United States)

    Pang, Yang; Prasad, Paras N.

    1990-08-01

    We have investigated the dynamics of resonant third-order optical nonlinearity of chemically prepared poly(3-dodecylthiophene) by the degenerate four wave mixing technique using 60 fs pulses at 620 nm. The measured effective value of χ(3) is 5.5×10-11 esu, sixfold smaller than that obtained with 400 fs pulses, emphasizing the pulse width dependence of effective χ(3) when the relaxation time of the photogenerated excitation responsible for the optical nonlinearity is comparable to the pulse width. Within the resolution of the optical pulse, the rise time of the nonlinear response is instantaneous and the dominant decay occurs within 200 fs, revealing that the short time, nonlinear response is derived from the initially photogenerated excitons. A detailed analysis of the total decay behavior is consistent with the polaron dynamics of the conformational deformation model proposed by Su, Schrieffer, and Heeger for a conjugated linear polymer with bond alternation.

  17. Detection of Parametric Roll Resonance on Ships from Indication of Nonlinear Energy Flow

    DEFF Research Database (Denmark)

    Galeazzi, Roberto; Blanke, Mogens; Poulsen, Niels Kjølstad

    2009-01-01

    The detection of the onset of parametric roll resonance on ships is of a central importance in order to activate specific control strategies able to counteract the large roll motion. One of the main priorities is to have detectors with a small detection time, such that warnings can be issued when...... the roll oscillations are about 5◦. This paper proposes two different detection approaches: the first one based on sinusoidal detection in white gaussian noise; the second one utilizes an energy flow indicator in order to catch the onset of parametric roll based upon the transfer of energy from heave...... and pitch to roll. Both detectors have been validated against experimental data of a scale model of a container vessel excited with both regular and irregular waves. The detector based on the energy flow indicator proved to be very robust to different scenarios (regular/irregular waves) since it does...

  18. Plasma-induced magnetic responses during nonlinear dynamics of magnetic islands due to resonant magnetic perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Seiya, E-mail: n-seiya@kobe-kosen.ac.jp [Kobe City College of Technology, Kobe, Hyogo 651-2194 (Japan)

    2014-12-15

    Resonant magnetic perturbations (RMPs) produce magnetic islands in toroidal plasmas. Self-healing (annihilation) of RMP-induced magnetic islands has been observed in helical systems, where a possible mechanism of the self-healing is shielding of RMP penetration by plasma flows, which is well known in tokamaks. Thus, fundamental physics of RMP shielding is commonly investigated in both tokamaks and helical systems. In order to check this mechanism, detailed informations of magnetic island phases are necessary. In experiments, measurement of radial magnetic responses is relatively easy. In this study, based on a theoretical model of rotating magnetic islands, behavior of radial magnetic fields during the self-healing is investigated. It is confirmed that flips of radial magnetic fields are typically observed during the self-healing. Such behavior of radial magnetic responses is also observed in LHD experiments.

  19. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...

  20. Triadic resonances in non-linear simulations of a fluid flow in a precessing cylinder

    CERN Document Server

    Giesecke, A; Gundrum, T; Herault, J; Stefani, F

    2015-01-01

    We present results from three-dimensional non-linear hydrodynamic simulations of a precession driven flow in cylindrical geometry. The simulations are motivated by a dynamo experiment currently under development at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in which the possibility of generating a magnetohydrodynamic dynamo will be investigated in a cylinder filled with liquid sodium and simultaneously rotating around two axes. In this study, we focus on the emergence of non-axisymmetric time-dependent flow structures in terms of inertial waves which - in cylindrical geometry - form so-called Kelvin modes. For a precession ratio ${\\rm{Po}}=\\Omega_p/\\Omega_c=0.014$ the amplitude of the forced Kelvin mode reaches up to one fourth of the rotation velocity of the cylindrical container confirming that precession provides a rather efficient flow driving mechanism even at moderate values of ${\\rm{Po}}$. More relevant for dynamo action might be free Kelvin modes with higher azimuthal wave number. These free Kelvin m...

  1. Nonlinear Resonant Excitation of Fast Sausage Waves in Current-Carrying Coronal Loops

    Science.gov (United States)

    Mikhalyaev, B. B.; Bembitov, D. B.

    2014-11-01

    We consider a model of a coronal loop that is a cylindrical magnetic tube with two surface electric currents. Its principal sausage mode has no cut-off in the long-wavelength limit. For typical coronal conditions, the period of the mode is between one and a few minutes. The sausage mode of flaring loops could cause long-period pulsations observed in microwave and hard X-ray ranges. There are other examples of coronal oscillations: long-period pulsations of active-region quiet loops in the soft X-ray emission are observed. We assume that these can also be caused by sausage waves. The question arises of how the sausage waves are generated in quiet loops. We assume that they can be generated by torsional oscillations. This process can be described in the framework of the nonlinear three-wave interaction formalism. The periods of interacting torsional waves are similar to the periods of torsional oscillations observed in the solar atmosphere. The timescale of the sausage-wave excitation is not much longer than the periods of interacting waves, so that the sausage wave is excited before torsional waves are damped.

  2. Impact of resonant magnetic perturbations on nonlinearly driven modes in drift-wave turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Leconte, M. [WCI Center for Fusion Theory, NFRI (Korea, Republic of); Diamond, P. H. [WCI Center for Fusion Theory, NFRI (Korea, Republic of); CMTFO and CASS, UCSD, California 92093 (United States)

    2012-05-15

    In this work, we study the effects of resonant magnetic perturbations (RMPs) on turbulence, flows, and confinement in the framework of resistive drift wave turbulence. We extend the Hasegawa-Wakatani model to include RMP fields. The effect of the RMPs is to induce a linear coupling between the zonal electric field and the zonal density gradient, which drives the system to a state of electron radial force balance for large ({delta}B{sub r}/B{sub 0}). Both the vorticity flux (Reynolds stress) and particle flux are modulated. We derive an extended predator prey model which couples zonal potential and density dynamics to the evolution of turbulence intensity. This model has both turbulence drive and RMP amplitude as control parameters and predicts a novel type of transport bifurcation in the presence of RMPs. We find states that are similar to the ZF-dominated state of the standard predator-prey model, but for which the power threshold is now a function of the RMP strength. For small RMP amplitude, the energy of zonal flows decreases and the turbulence energy increases with ({delta}B{sub r}/B{sub 0}), corresponding to a damping of zonal flows.

  3. Fano lines in the reflection spectrum of directly coupled systems of waveguides and cavities: measurements, modeling and manipulation of the Fano asymmetry

    CERN Document Server

    Lian, Jin; Yüce, Emre; Combrié, Sylvain; De Rossi, Alfredo; Mosk, Allard P

    2016-01-01

    We measure and analyze reflection spectra of directly coupled systems of waveguides and cavities. The observed Fano lines offer insight in the reflection and coupling processes. We show their shape can be understood and manipulated by varying experimental parameters.

  4. Size-dependent Fano Interaction in the Laser-etched Silicon Nanostructures

    Directory of Open Access Journals (Sweden)

    Kumar Rajesh

    2008-01-01

    Full Text Available AbstractPhoto-excitation and size-dependent Raman scattering studies on the silicon (Si nanostructures (NSs prepared by laser-induced etching are presented here. Asymmetric and red-shifted Raman line-shapes are observed due to photo-excited Fano interaction in the quantum confined nanoparticles. The Fano interaction is observed between photo-excited electronic transitions and discrete phonons in Si NSs. Photo-excited Fano studies on different Si NSs show that the Fano interaction is high for smaller size of Si NSs. Higher Fano interaction for smaller Si NSs is attributed to the enhanced interference between photo-excited electronic Raman scattering and phonon Raman scattering.

  5. Linear and Non-linear Rabi Oscillations of a Two-Level System Resonantly Coupled to an Anderson-Localized Mode

    CERN Document Server

    Bachelard, Nicolas; Sebbah, Patrick; Vanneste, Christian

    2014-01-01

    We use time-domain numerical simulations of a two-dimensional (2D) scattering system to study the interaction of a collection of emitters resonantly coupled to an Anderson-localized mode. For a small electric field intensity, we observe the strong coupling between the emitters and the mode, which is characterized by linear Rabi oscillations. Remarkably, a larger intensity induces non-linear interaction between the emitters and the mode, referred to as the dynamical Stark effect, resulting in non-linear Rabi oscillations. The transition between both regimes is observed and an analytical model is proposed which accurately describes our numerical observations.

  6. Inducing Strong Nonlinearities in a High-$Q$ System: Coupling of a Bulk Acoustic Wave Quartz Resonator to a Superconducting Quantum Interference Device

    CERN Document Server

    Goryachev, Maxim; Galliou, Serge; Tobar, Michael E

    2015-01-01

    A system consisting of a SQUID amplifier coupled to a Bulk Acoustic Wave resonator is investigated experimentally from the small to large signal regimes. Both parallel and series connection topologies of the system are verified. The study reveals significant non-Duffing response that is associated with the nonlinear characteristics of Josephson junctions. The nonlinearity provides quasi-periodic structure of the spectrum in both incident power and frequency. The result gives an insight into the open loop behaviour of a future Cryogenic Quartz Oscillator operating with a SQUID amplifier as the active device.

  7. Nonlinear flexural response of a slender cantilever beam of constant thickness and linearly-varying width to a primary resonance excitation

    Science.gov (United States)

    Silva, Clodoaldo J.; Daqaq, Mohammed F.

    2017-02-01

    Despite the shear amount of research studies on nonlinear flexural dynamics of cantilever beams, very few efforts address the practical geometry involving a constant thickness and linearly-varying width. This stems from the nature of the associated linear eigenvalue problem which cannot be easily solved in closed form. In this paper, we present a closed-form solution to this particular linear eigenvalue problem in the form of a general Meijer-G differential equation for which a solution is readily available in the shape of the Meijer-G functions. Using this approach, the exact linear modal frequencies and shapes are obtained and used in the discretization of the nonlinear partial-differential equation describing the dynamics of the system. The discretized system of ordinary-differential equations is then solved using the method of multiple scales to obtain an approximate analytical solution describing the primary resonance behavior of a given vibration mode. An analytical expression for the modal effective nonlinearity is obtained and used to analyze the influence of the beam's tapering on the nonlinear primary resonance behavior of the response (softening/hardening). Results are then compared to a finite element (FE) solution of the linear eigenvalue problem in which the modal shapes obtained using the FE method are fit into a set of orthogonal polynomial functions and used to discretize the nonlinear problem. It is shown that, while the modal frequencies obtained using the FE method approximate those obtained analytically with negligible error (less than 1%), there is a substantial error in the resulting estimates of the modal effective nonlinearity. This indicates that, even negligible errors in the approximate solution of the linear problem, can propagate to become significant when analyzing the nonlinear problem further reinforcing the importance of the exact solution.

  8. A Pair of Resonance Stripe Solitons and Lump Solutions to a Reduced (3+1)-Dimensional Nonlinear Evolution Equation

    Science.gov (United States)

    Chen, Mei-Dan; Li, Xian; Wang, Yao; Li, Biao

    2017-06-01

    With symbolic computation, some lump solutions are presented to a (3+1)-dimensional nonlinear evolution equation by searching the positive quadratic function from the Hirota bilinear form of equation. The quadratic function contains six free parameters, four of which satisfy two determinant conditions guaranteeing analyticity and rational localization of the solutions, while the others are free. Then, by combining positive quadratic function with exponential function, the interaction solutions between lump solutions and the stripe solitons are presented on the basis of some conditions. Furthermore, we extend this method to obtain more general solutions by combining of positive quadratic function and hyperbolic cosine function. Thus the interaction solutions between lump solutions and a pair of resonance stripe solitons are derived and asymptotic property of the interaction solutions are analyzed under some specific conditions. Finally, the dynamic properties of these solutions are shown in figures by choosing the values of the parameters. Supported by National Natural Science Foundation of China under Grant Nos. 11271211, 11275072, and 11435005, Ningbo Natural Science Foundation under Grant No. 2015A610159 and the Opening Project of Zhejiang Provincial Top Key Discipline of Physics Sciences in Ningbo University under Grant No. xkzw11502 and K.C. Wong Magna Fund in Ningbo University

  9. Extreme and superextreme events in a loss-modulated CO2 laser: Nonlinear resonance route and precursors

    Science.gov (United States)

    Bonatto, Cristian; Endler, Antonio

    2017-07-01

    We investigate the occurrence of extreme and rare events, i.e., giant and rare light pulses, in a periodically modulated CO2 laser model. Due to nonlinear resonant processes, we show a scenario of interaction between chaotic bands of different orders, which may lead to the formation of extreme and rare events. We identify a crisis line in the modulation parameter space, and we show that, when the modulation amplitude increases, remaining in the vicinity of the crisis, some statistical properties of the laser pulses, such as the average and dispersion of amplitudes, do not change much, whereas the amplitude of extreme events grows enormously, giving rise to extreme events with much larger deviations than usually reported, with a significant probability of occurrence, i.e., with a long-tailed non-Gaussian distribution. We identify recurrent regular patterns, i.e., precursors, that anticipate the emergence of extreme and rare events, and we associate these regular patterns with unstable periodic orbits embedded in a chaotic attractor. We show that the precursors may or may not lead to the emergence of extreme events. Thus, we compute the probability of success or failure (false alarm) in the prediction of the extreme events, once a precursor is identified in the deterministic time series. We show that this probability depends on the accuracy with which the precursor is identified in the laser intensity time series.

  10. Fano interference and a slight fluctuation of the Majorana hallmark

    Energy Technology Data Exchange (ETDEWEB)

    Seridonio, A. C. [Instituto de Geociências e Ciências Exatas-IGCE, Universidade Estadual Paulista, Departamento de Física, 13506-970, Rio Claro, São Paulo (Brazil); Departamento de Física e Química, Universidade Estadual Paulista, 15385-000, Ilha Solteira, São Paulo (Brazil); Siqueira, E. C.; Dessotti, F. A.; Machado, R. S. [Departamento de Física e Química, Universidade Estadual Paulista, 15385-000, Ilha Solteira, São Paulo (Brazil); Yoshida, M. [Instituto de Geociências e Ciências Exatas-IGCE, Universidade Estadual Paulista, Departamento de Física, 13506-970, Rio Claro, São Paulo (Brazil)

    2014-02-14

    According to the Liu and Baranger [Phys. Rev. B 84, 201308(R) (2011)], an isolated Majorana state bound to one edge of a long enough Kitaev chain in the topological phase and connected to a quantum dot, results in a robust transmittance of 1/2 at zero-bias. In this work, we show that the removal of such a hallmark can be achieved by using a metallic surface hosting two adatoms in a scenario where there is a lack of symmetry in the Fano effect, which is feasible by coupling the Kitaev chain to one of these adatoms. Thus in order to detect this feature experimentally, one should apply the following two-stage procedure: (i) first, attached to the adatoms, one has to lock AFM tips in opposite gate voltages (symmetric detuning of the levels Δε) and measure by an STM tip, the zero-bias conductance; (ii) thereafter, the measurement of the conductance is repeated with the gates swapped. For |Δε| away from the Fermi energy and in the case of strong coupling tip-host, this approach reveals in the transmittance, a persistent dip placed at zero-bias and immune to the aforementioned permutation, but characterized by an amplitude that fluctuates slightly around 1/2. However, in the case of a tip acting as a probe, the adatom decoupled from the Kitaev chain becomes completely inert and no fluctuation is observed. Therefore, the STM tip must be considered in the same footing as the “host+adatoms” system. As a result, we have found that despite the small difference between these two Majorana dips, the zero-bias transmittance as a function of the symmetric detuning yields two distinct behaviors, in which one of them is unpredictable by the standard Fano's theory. Therefore, to access such a non trivial pattern of Fano interference, the hypothesis of the STM tip acting as a probe should be discarded.

  11. Geant4 and Fano cavity test: where are we?

    CERN Document Server

    Elles, S; Maire, M; Urbàn, L

    2008-01-01

    The electron transport algorithm implemented in Geant4 has been recently revised. The modifications concern several physics aspects of the simulation model: the step limitation, the energy loss along a step and the multiple scattering. The Fano cavity setup was used to test these developments. The upgrades increase significantly the accuracy of the electron transport simulation. The ratio of simulated to theoretical dose deposition in the cavity is stable to ~1% while varying several parameters and within ~1.5% of the expected value for water and graphite. Work is underway to identify and resolve the remaining shift.

  12. Enfermería en Quirófano

    OpenAIRE

    2015-01-01

    Quirófano es un área especial en el que se desarrollan intervenciones quirúrgicas. Tiene unas características concretas en cuanto a su localización y distribución física. Debe estar situado céntricamente y bien comunicado con los servicios especiales del hospital (urgencias, laboratorios, esterilización, hospitalización…) En cuanto a su distribución, está dividido en áreas (no restringida, semi-restringida y restringida) cuyas normas de ropa, tránsito de personal y material son diferentes. Se...

  13. Metamaterials with toroidal fano-response (Conference Presentation)

    Science.gov (United States)

    Kozhokar, Maria V.; Basharin, Alexey A.

    2017-05-01

    The static toroidal dipole was predicted by Zeldovich, which appears due to the static currents in atomic nuclei and explain disturbance of parity in the weak interaction. Physically, toroidal dipole is separated element of multipole expansion that corresponds to electrical currents circulating on a surface of gedanken torus along its meridians. Recently, the demonstration of dynamic toroidal dipolar response became possible in metamaterials composed of metamolecules of toroidal topology. Metamaterials with toroidal dipolar response allow to demonstrate a number of special properties such as novel type of EIT, optical activity, extremely strongly localized fields and anapole. We are interested in another property of toroidal metamaterials - magnetic Fano-type response caused by toroidal and magnetic moments in a particular metamolecule. In this paper we demonstrate theoretically and experimentally in microwave at the first time Fano-excitation in toroidal metamaterials. We suggested metamaterials based on a special structure of two types of planar metamolecules separated by dielectric layer. One of them "Electric" type metamolecule is a planar conductive structure consisting of two symmetric split loops. The incident plane wave excites circular currents along the loops leading to a circulating magnetic moment and, as a result, to a toroidal moment. Moreover, due to the central gap electric moment can be excited in metamolecule. At the same time, destructive/constructive interference between toroidal and electric dipolar moments gives us unique effect as very strong E- field localization inside the central gap and anapole mode. "Magnetic" type metamolecule is the inverted and rotated variant of the first structure. In contrast to the first case, here we expect very strong localization of magnetic field instead electric field. The magnetic field lines are whirling around the central junction of the metamolecule due to interference between toroidal and magnetic

  14. Nonlinear oscillation of nanoelectro-mechanical resonators using energy balance method: considering the size effect and the van der Waals force

    Science.gov (United States)

    Ghalambaz, Mohammad; Ghalambaz, Mehdi; Edalatifar, Mohammad

    2016-03-01

    The energy balance method is utilized to analyze the oscillation of a nonlinear nanoelectro-mechanical system resonator. The resonator comprises an electrode, which is embedded between two substrates. Two types of clamped-clamped and cantilever nano-resonators are studied. The effects of the van der Waals attractions, Casimir force, the small size, the fringing field, the mid-plane stretching, and the axial load are taken into account. The governing partial differential equation of the resonator is reduced using the Galerkin method. The energy method is applied to obtain an analytical solution without considering any linearization or small parameter. The results of the present study are compared with the results available in the literature. In addition, the results of the present analytical solution are compared with the Runge-Kutta numerical results. An excellent agreement between the present analytical solution, numerical solution, and the results available in the literature was found. The influences of the van der Waals force, Casimir force, size effect, and fringing field effect on the oscillation frequency of resonators are studied. The results indicate that the presence of the intermolecular forces (van der Waals), Casimir force, and fringing field effect decreases the oscillation frequency of the resonator. In contrast, the presence of the size effect increases the oscillation frequency of the resonator.

  15. Effect of Zn addition on non-resonant third-order optical nonlinearity of the Cu-doped germano-silicate optical glass fiber.

    Science.gov (United States)

    Ju, Seongmin; Watekar, Pramod R; Jeong, Seongmook; Kim, Youngwoong; Han, Won-Taek

    2012-01-01

    Cu/Zn-codoped germano-silicate optical glass fiber was manufactured by using the modified chemical vapor deposition (MCVD) process and solution doping process. To investigate the reduction effect of Zn addition on Cu metal formation in the core of the Cu/Zn-codoped germano-silicate optical glass fiber, the optical absorption property and the non-resonant third-order optical nonlinearity were measured. Absorption peaks at 435 nm and 469 nm in the Cu/Zn-codoped germano-silicate optical glass fiber were contributed to Cu metal particles and ZnO semiconductor particles, respectively. The effective non-resonant optical nonlinearity, gamma, of the Cu/Zn-codoped germano-silicate optical glass fiber was measured to be 1.5097 W(-1) x km(-1) by using the continuous-wave self-phase modulation method. The gamma of the Cu/Zn-codoped germano-silicate optical glass fiber was about four times larger than that of the reference germano-silicate optical glass fiber without any dopants. The increase of the effective non-resonant optical nonlinearity, gamma, of the Cu/Zn-codoped germano-silicate optical glass fiber, can be attributed to the enhanced nonlinear polarization due to incorporated ZnO semiconductor particles and Cu metal ions in the glass network. The Cu/Zn-codoped germano-silicate optical glass fiber showed high nonlinearity and low transmission loss at the optical communication wavelength, which makes it suitable for high-speed-high-capacity optical communication systems.

  16. Large resonant third-order optical nonlinearity of thin film containing J-like aggregates of a bis[4-(-dibutylamino)phenyl]squarylium dye

    Indian Academy of Sciences (India)

    Zhongyu Li; Song Xu; Lin Zhu; Kazuo Kasatani

    2012-12-01

    The third-order optical nonlinearity and response of thin film containing J-like aggregates of a bis[4-(-dibutylamino)phenyl]squarylium dye were measured by degenerate four-wave mixing (DFWM) technique under resonant conditions. The temporal profile of DFWM signal was obtained with a time resolution of 0.3 ps (FWHM), and was found to consist of at least two components, i.e. the coherent instantaneous nonlinear response (electronic response) and the slow response due to the excited state population grating. The effective (3) value of thin squarylium dye film was evaluated to be as high as 1.1 × 10-7 esu, and the figure of merit of third-order nonlinearity ( = (3)/), was calculated to be about 2.1 × 10-13 esu cm.

  17. Probing the antisymmetric Fano interference assisted by a Majorana fermion

    Energy Technology Data Exchange (ETDEWEB)

    Dessotti, F. A.; Ricco, L. S. [Departamento de Física e Química, Unesp - Univ Estadual Paulista, 15385-000 Ilha Solteira, São Paulo (Brazil); Souza, M. de [Departamento de Física, IGCE, Unesp - Univ Estadual Paulista, 13506-900 Rio Claro, São Paulo (Brazil); Souza, F. M. [Instituto de Física, Universidade Federal de Uberlândia, 38400-902 Uberlândia, Minas Gerais (Brazil); Seridonio, A. C. [Departamento de Física e Química, Unesp - Univ Estadual Paulista, 15385-000 Ilha Solteira, São Paulo (Brazil); Departamento de Física, IGCE, Unesp - Univ Estadual Paulista, 13506-900 Rio Claro, São Paulo (Brazil)

    2014-11-07

    As the Fano effect is an interference phenomenon where tunneling paths compete for the electronic transport, it becomes a probe to catch fingerprints of Majorana fermions lying on condensed matter systems. In this work, we benefit of this mechanism by proposing as a route for that an Aharonov-Bohm-like interferometer composed by two quantum dots, being one of them coupled to a Majorana bound state, which is attached to one of the edges of a semi-infinite Kitaev wire within the topological phase. By changing the Fermi energy of the leads and the symmetric detuning of the levels for the dots, we show that opposing Fano regimes result in a transmittance characterized by distinct conducting and insulating regions, which are fingerprints of an isolated Majorana quasiparticle. Furthermore, we show that the maximum fluctuation of the transmittance as a function of the detuning is half for a semi-infinite wire, while it corresponds to the unity for a finite system. The setup proposed here constitutes an alternative experimental tool to detect Majorana excitations.

  18. Impact of the Fano Factor on Position and Energy Estimation in Scintillation Detectors.

    Science.gov (United States)

    Bora, Vaibhav; Barrett, Harrison H; Jha, Abhinav K; Clarkson, Eric

    2015-02-01

    The Fano factor for an integer-valued random variable is defined as the ratio of its variance to its mean. Light from various scintillation crystals have been reported to have Fano factors from sub-Poisson (Fano factor factor > 1). For a given mean, a smaller Fano factor implies a smaller variance and thus less noise. We investigated if lower noise in the scintillation light will result in better spatial and energy resolutions. The impact of Fano factor on the estimation of position of interaction and energy deposited in simple gamma-camera geometries is estimated by two methods - calculating the Cramér-Rao bound and estimating the variance of a maximum likelihood estimator. The methods are consistent with each other and indicate that when estimating the position of interaction and energy deposited by a gamma-ray photon, the Fano factor of a scintillator does not affect the spatial resolution. A smaller Fano factor results in a better energy resolution.

  19. On the Higgsing and UnHiggsing of Fano 3-Folds

    CERN Document Server

    Phukon, Prabwal

    2011-01-01

    We study the Higgsing and UnHiggsing of M2-brane theories that probe cones over smooth toric Fano 3-folds, via brane tilings. We find many new examples of M2-brane gauge theories not studied previously in the literature, including those that do not correspond to cones over Fano varieties. Our analysis also provides, upon unHiggsing the known Fano varieties, new examples of quiver gauge theories that describe the same toric variety, but with external point multiplicities. As a byproduct of our results, we discuss an example of a CY 4-fold that does not have a tiling description, and study the Higgsing of this theory.

  20. On the Higgsing and UnHiggsing of Fano 3-Folds

    OpenAIRE

    Phukon, Prabwal; Sarkar, Tapobrata

    2011-01-01

    We study the Higgsing and UnHiggsing of M2-brane theories that probe cones over smooth toric Fano 3-folds, via brane tilings. We find many new examples of M2-brane gauge theories not studied previously in the literature, including those that do not correspond to cones over Fano varieties. Our analysis also provides, upon unHiggsing the known Fano varieties, new examples of quiver gauge theories that describe the same toric variety, but with external point multiplicities. As a byproduct of our...