WorldWideScience

Sample records for nonlinear fano resonance

  1. Acoustic Fano resonators

    KAUST Repository

    Amin, Muhammad; Farhat, Mohamed; Bagci, Hakan

    2014-01-01

    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

  2. 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.

  3. 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).

  4. All-optical switching based on a tunable Fano-like resonance in nonlinear ferroelectric photonic crystals

    International Nuclear Information System (INIS)

    Chai, Zhen; Hu, Xiaoyong; Gong, Qihuang

    2013-01-01

    A low-power all-optical switching is presented based on the all-optical tunable Fano-like resonance in a two-dimensional nonlinear ferroelectric photonic crystal made of polycrystalline lithium niobate. An asymmetric Fano-like line shape is achieved in the transmission spectrum by using two cascaded and uncoupled photonic crystal microcavities. The physical mechanism underlying the all-optical switching is attributed to the dynamic shift of the Fano-like resonance peak caused by variations in the dispersion relations of the photonic crystal structure induced by pump light. A large switching efficiency of 61% is reached under excitation of a weak pump light with an intensity as low as 1 MW cm −2 . (paper)

  5. 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.

  6. 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...

  7. Fano resonances in bilayer phosphorene nanoring

    Science.gov (United States)

    Zhang, Rui; Wu, Zhenhua; Li, X. J.; Li, L. L.; Chen, Qiao; Li, Yun-Mei; Peeters, F. M.

    2018-05-01

    Tunable transport properties and Fano resonances are predicted in a circular bilayer phosphorene nanoring. The conductance exhibits Fano resonances with varying incident energy and applied perpendicular magnetic field. These Fano resonance peaks can be accurately fitted with the well known Fano curves. When a magnetic field is applied to the nanoring, the conductance oscillates periodically with magnetic field which is reminiscent of the Aharonov–Bohm effect. Fano resonances are tightly related to the discrete states in the central nanoring, some of which are tunable by the magnetic field.

  8. Double Fano resonances in plasmon coupling nanorods

    International Nuclear Information System (INIS)

    Liu, Fei; Jin, Jie

    2015-01-01

    Fano resonances are investigated in nanorods with symmetric lengths and side-by-side assembly. Single Fano resonance can be obtained by a nanorod dimer, and double Fano resonances are shown in nanorod trimers with side-by-side assembly. With transverse plasmon excitation, Fano resonances are caused by the destructive interference between a bright superradiant mode and dark subradiant modes. The bright mode originates from the electric plasmon resonance, and the dark modes originate from the magnetic resonances induced by near-field inter-rod coupling. Double Fano resonances result from double dark modes at different wavelengths, which are induced and tuned by the asymmetric gaps between the adjacent nanorods. Fano resonances show a high figure of merit and large light extinction in the periodic array of assembled nanorods, which can potentially be used in multiwavelength sensing in the visible and near-infrared regions. (paper)

  9. Improved switching using Fano resonances in photonic crystal structures

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...

  10. Investigations on the parity of Fano resonances in photonic crystals

    DEFF Research Database (Denmark)

    Østerkryger, Andreas Dyhl; de Lasson, Jakob Rosenkrantz; Yu, Yi

    We investigate the relation between the parity of Fano resonances and field distribution in a photonic crystal structure using Fourier modal method, establishing a correlation between Fano parity and field profile.......We investigate the relation between the parity of Fano resonances and field distribution in a photonic crystal structure using Fourier modal method, establishing a correlation between Fano parity and field profile....

  11. 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...

  12. 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 ...... reshaping effect of the nonlinear Fano transfer function. As an example, we present a system application of a Fano structure, demonstrating its advantages by the experimental realiza- tion of 10 Gbit/s all-optical modulation with optical control power less than 1mW.......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...

  13. Magnetically coupled Fano resonance of dielectric pentamer oligomer

    International Nuclear Information System (INIS)

    Zhang, Fuli; Li, Chang; He, Xuan; Chen, Lei; Fan, Yuancheng; Zhao, Qian; Zhang, Weihong; Zhou, Ji

    2017-01-01

    We present magnetically induced Fano resonance inside a dielectric metamaterial pentamer composed of ceramic bricks. Unlike previous reports where different sizes of dielectric resonators were essential to produce Fano resonance, under external magnetic field excitation, central and outer dielectric bricks with identical sizes exhibit in-phase and out-of-phase magnetic Mie oscillations. An asymmetric line shape of Fano resonance along with enhanced group delay is observed due to the interference between the magnetic resonance of the central brick and the symmetric magnetic resonance of outer bricks. Besides, Fano resonance blueshifts with the increasing resonance of the smaller central brick. The thermal-dependent permittivity of ceramics allows Fano resonance to be reversibly tuned by 300 MHz when temperature varies by 60 °C. (paper)

  14. 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 eleme......-element simulations. Our approach can be used for development of next generation of tunable plasmonic and hybrid nanophotonic devices.......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...... elements enhances the interaction of incident radiation with the graphene sheet and enables efficient electrical modulation of the plasmonic resonance. We observe electrically controlled damping in the Fano resonances occurring at approximately 2 μm, and the results are verified by full-wave 3D finite...

  15. 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

  16. Ellipsoidal all-dielectric Fano resonant core-shell metamaterials

    Science.gov (United States)

    Reena, Reena; Kalra, Yogita; Kumar, Ajeet

    2018-06-01

    In this paper, ellipsoidal core (Si) and shell (SiO2) metamaterial has been proposed for highly directional properties. At the wavelength of magnetic resonance, Fano dip occurs in the backward scattering cross section and forward scattering enhancement takes place at the same wavelength so that there is an increment in the directivity. Effect on the directivity by changing the length of ellipsoidal nanoparticle along semi-axes has been analyzed. Two Fano resonances have been observed by decreasing the length of the nanoparticle along the semi-axis having electric polarization, where first and second Fano resonances are attributed to the dipole and quadrupole moments, respectively. These Fano resonant wavelengths in ellipsoidal nanoparticle exhibit higher directivity than the Kerker's type scattering or forward scattering shown by symmetrical structures like sphere. So, this core-shell metamaterial can act as an efficient directional nanoantenna.

  17. Pulse carving using nanocavity-enhanced nonlinear effects in photonic crystal Fano structures

    DEFF Research Database (Denmark)

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

    2018-01-01

    We experimentally demonstrate the use of a photonic crystal Fano resonance for carving-out short pulses from long-duration input pulses. This is achieved by exploiting an asymmetric Fano resonance combined with carrier-induced nonlinear effects in a photonic crystal membrane structure. The use...... of a nanocavity concentrates the input field to a very small volume leading to an efficient nonlinear resonance shift that carves a short pulse out of the input pulse. Here, we demonstrate shortening of ∼500  ps and ∼100  ps long pulses to ∼30  ps and ∼20  ps pulses, respectively. Furthermore, we demonstrate...

  18. 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.

  19. Acoustically induced transparency using Fano resonant periodic arrays

    KAUST Repository

    El-Amin, Mohamed; Elayouch, A.; Farhat, Mohamed; Addouche, M.; Khelif, A.; Bagci, Hakan

    2015-01-01

    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. Design of Fano Resonators for Novel Metamaterial Applications

    KAUST Repository

    Amin, Muhammad

    2014-01-01

    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 effective refractive index required by sensing

  1. Fano resonance and persistent current of a quantum ring

    International Nuclear Information System (INIS)

    Xiong Yongjian; Liang Xianting

    2004-01-01

    We investigate electron transport and persistent current of a quantum ring weakly attached to current leads. Assuming there is direct coupling (weakly or strongly) between two leads, electrons can transmit by the inter-lead coupling or tunneling through the quantum ring. The interference between the two paths yields asymmetric Fano line shape for conductance. In presence of interior magnetic flux, there is persistent current along the ring with narrow resonance peaks. The positions of the conductance resonances and the persistent current peaks correspond to the quasibound levels of the closed ring. This feature is helpful to determine the energy spectrum of the quantum ring. Our results show that the proposed setup provides a tunable Fano system

  2. Fano resonance in anodic aluminum oxide based photonic crystals.

    Science.gov (United States)

    Shang, Guo Liang; Fei, Guang Tao; Zhang, Yao; Yan, Peng; Xu, Shao Hui; Ouyang, Hao Miao; Zhang, Li De

    2014-01-08

    Anodic aluminum oxide based photonic crystals with periodic porous structure have been prepared using voltage compensation method. The as-prepared sample showed an ultra-narrow photonic bandgap. Asymmetric line-shape profiles of the photonic bandgaps have been observed, which is attributed to Fano resonance between the photonic bandgap state of photonic crystal and continuum scattering state of porous structure. And the exhibited Fano resonance shows more clearly when the sample is saturated ethanol gas than air-filled. Further theoretical analysis by transfer matrix method verified these results. These findings provide a better understanding on the nature of photonic bandgaps of photonic crystals made up of porous materials, in which the porous structures not only exist as layers of effective-refractive-index material providing Bragg scattering, but also provide a continuum light scattering state to interact with Bragg scattering state to show an asymmetric line-shape profile.

  3. Full controlling of Fano resonances in metal-slit superlattice.

    Science.gov (United States)

    Deng, Zi-Lan; Yogesh, Natesan; Chen, Xiao-Dong; Chen, Wen-Jie; Dong, Jian-Wen; Ouyang, Zhengbiao; Wang, Guo Ping

    2015-12-18

    Controlling of the lineshape of Fano resonance attracts much attention recently due to its wide capabilities for lasing, biosensing, slow-light applications and so on. However, the controllable Fano resonance always requires stringent alignment of complex symmetry-breaking structures and thus the manipulation could only be performed with limited degrees of freedom and narrow tuning range. Furthermore, there is no report so far on independent controlling of both the bright and dark modes in a single structure. Here, we semi-analytically show that the spectral position and linewidth of both the bright and dark modes can be tuned independently and/or simultaneously in a simple and symmetric metal-slit superlattice, and thus allowing for a free and continuous controlling of the lineshape of both the single and multiple Fano resonances. The independent controlling scheme is applicable for an extremely large electromagnetic spectrum range from optical to microwave frequencies, which is demonstrated by the numerical simulations with real metal and a microwave experiment. Our findings may provide convenient and flexible strategies for future tunable electromagnetic devices.

  4. Quantum interference in the system of Lorentzian and Fano magnetoexciton resonances in GaAs

    International Nuclear Information System (INIS)

    Siegner, U.; Mycek, M.; Glutsch, S.; Chemla, D.S.

    1995-01-01

    Using femtosecond four-wave mixing (FWM), we study the coherent dynamics of Lorentzian and Fano magnetoexciton resonances in GaAs. For unperturbed Lorentzian magnetoexcitons, we find that the time-integrated FWM signal decays due to dephasing processes as expected for Lorentzian resonances. The time-integrated FWM signal from a single Fano magnetoexciton resonance, however, decays quasi-instantaneously although the dephasing time of the Fano resonance is much longer than the time resolution of the experiment. This fast decay is the manifestation of destructive quantum interference. Although destructive quantum interference in our system is closely related to the dynamics of Fano resonances, for the simultaneous excitation of Lorentzian and Fano magnetoexciton resonances destructive quantum interference also strongly affects the dynamics of Lorentzian magnetoexcitons due to quantum-mechanical coupling between the two types of resonances

  5. 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...

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

    KAUST Repository

    Elayouch, A.; Addouche, M.; Farhat, Mohamed; El-Amin, Mohamed; Bagci, Hakan; Khelif, A.

    2017-01-01

    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

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

    International Nuclear Information System (INIS)

    Zhang, Fan; Wu, Chenyun; Yang, Hong; Hu, Xiaoyong; Gong, Qihuang

    2014-01-01

    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

  8. 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.

  9. Enhanced Faraday rotation in one dimensional magneto-plasmonic structure due to Fano resonance

    Science.gov (United States)

    Sadeghi, S.; Hamidi, S. M.

    2018-04-01

    Enhanced Faraday rotation in a new type of magneto-plasmonic structure with the capability of Fano resonance, has been reported theoretically. A magneto-plasmonic structure composed of a gold corrugated layer deposited on a magneto-optically active layer was studied by means of Lumerical software based on finite-difference time-domain. In our proposed structure, plasmonic Fano resonance and localized surface plasmon have induced enhancement in magneto-optical Faraday rotation. It is shown that the influence of geometrical parameters in gold layer offers a desirable platform for engineering spectral position of Fano resonance and enhancement of Faraday rotation.

  10. Multiple Fano-Like MIM Plasmonic Structure Based on Triangular Resonator for Refractive Index Sensing

    OpenAIRE

    Jankovic, Nikolina; Cselyuszka, Norbert

    2018-01-01

    In this paper, we present a Fano metal-insulator-metal (MIM) structure based on an isosceles triangular cavity resonator for refractive index sensing applications. Due to the specific feeding scheme and asymmetry introduced in the triangular cavity, the resonator exhibits four sharp Fano-like resonances. The behavior of the structure is analyzed in detail and its sensing capabilities demonstrated through the responses for various refractive indices. The results show that the sensor has very g...

  11. 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.

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

    KAUST Repository

    Panaro, Simone; Nazir, Adnan; Zaccaria, Remo Proietti; Liberale, Carlo; De Angelis, Francesco; Toma, Andrea

    2015-01-01

    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.

  13. High Quality Plasmonic Sensors Based on Fano Resonances Created through Cascading Double Asymmetric Cavities

    OpenAIRE

    Zhang, Xiangao; Shao, Mingzhen; Zeng, Xiaoqi

    2016-01-01

    In this paper, a type of compact nanosensor based on a metal-insulator-metal structure is proposed and investigated through cascading double asymmetric cavities, in which their metal cores shift along different axis directions. The cascaded asymmetric structure exhibits high transmission and sharp Fano resonance peaks via strengthening the mutual coupling of the cavities. The research results show that with the increase of the symmetry breaking in the structure, the number of Fano resonances ...

  14. Tunable Fano Resonance in Asymmetric MIM Waveguide Structure.

    Science.gov (United States)

    Zhao, Xuefeng; Zhang, Zhidong; Yan, Shubin

    2017-06-25

    A plasmonic waveguide coupled system that uses a metal-insulator-metal (MIM) waveguide with two silver baffles and a coupled ring cavity is proposed in this study. The transmission properties of the plasmonic system were investigated using the finite element method. The simulation results show a Fano profile in the transmission spectrum, which was caused by the interaction of the broadband resonance of the Fabry-Perot (F-P) cavity and the narrow band resonance of the ring cavity. The Fabry-Perot (F-P) cavity in this case was formed by two silver baffles dividing the MIM waveguide. The maximum sensitivity of 718 nm/RIU and the maximum figure of merit of 4354 were achieved. Furthermore, the effects of the structural parameters of the F-P cavity and the ring cavity on the transmission properties of the plasmonic system were analyzed. The results can provide a guide for designing highly sensitive on-chip sensors based on surface plasmon polaritons.

  15. Fano resonance of the ultrasensitve optical force excited by Gaussian evanescent field

    International Nuclear Information System (INIS)

    Yang, Yang; Li, Jiafang; Li, Zhi-Yuan

    2015-01-01

    In this paper, we study the angle-dependent Fano-like optical force spectra of plasmonic Ag nanoparticles, which exhibit extraordinary transformation from Lorentzian resonance to Fano resonance when excited by a Gaussian evanescent wave. We systematically analyze the behavior of this asymmetric scattering induced optical force under different conditions and find that this Fano interference-induced force is ultrasensitive to the excitation wavelength, incident angle and particle size, as well as the core–shell configuration, which could be useful for wavelength- and angle-dependent size-selective optical manipulation. The origin of this Fano resonance is further identified as the interference between the two adjacent-order multipolar plasmonic modes excited in the Ag particle under the excitation of an inhomogeneously distributed evanescent field. (paper)

  16. Vibrational Fano resonances in the photodetachment of dipole-bound anions

    International Nuclear Information System (INIS)

    Edwards, Stephen T; Tully, John C; Johnson, Mark A

    2012-01-01

    A simple model for the photodetachment of dipole-bound anions is proposed where non-adiabatic coupling of vibrational states leads to a Fano resonance in the spectrum. It is found that the shape of the photodetachment spectrum depends significantly on the parameter representing molecular polarizability. The model is also applied to a Fano profile observed in the photodetachment of small water cluster anions.

  17. 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...

  18. Transmission gaps, trapped modes and Fano resonances in Aharonov-Bohm connected mesoscopic loops

    Science.gov (United States)

    Mrabti, T.; Labdouti, Z.; El Abouti, O.; El Boudouti, E. H.; Fethi, F.; Djafari-Rouhani, B.

    2018-03-01

    A simple mesoscopic structure consisting of a double symmetric loops coupled by a segment of length d0 in the presence of an Aharonov-Bohm flux is designed to obtain transmission band gaps and Fano resonances. A general analytical expression for the transmission coefficient and the density of states (DOS) are obtained for various systems of this kind within the framework of the Green's function method in the presence of the magnetic flux. In this work, the amplitude of the transmission and DOS are discussed as a function of the wave vector. We show that the transmission spectrum of the whole structure may exhibit a band gap and a resonance of Fano type without introducing any impurity in one arm of the loop. In particular, we show that for specific values of the magnetic flux and the lengths of the arms constituting the loops, the Fano resonance collapses giving rise to the so-called trapped states or bound in continuum (BIC) states. These states appear when the width of the Fano resonance vanishes in the transmission coefficient as well as in the density of states. Also, we show that the shape of the Fano resonances and the width of the band gaps are very sensitive to the value of the magnetic flux and the geometry of the structure. These results may have important applications for electronic transport in mesoscopic systems.

  19. Photonic crystal Fano lasers and Fano switches

    DEFF Research Database (Denmark)

    Mørk, Jesper; Yu, Yi; Bekele, Dagmawi Alemayehu

    2017-01-01

    We show that Fano resonances can be realized in photonic crystal membrane structures by coupling line-defect waveguides and point-defect nanocavities. The Fano resonance can be exploited to realize optical switches with very small switching energy, as well as Fano lasers, that can generate short...

  20. High Quality Plasmonic Sensors Based on Fano Resonances Created through Cascading Double Asymmetric Cavities.

    Science.gov (United States)

    Zhang, Xiangao; Shao, Mingzhen; Zeng, Xiaoqi

    2016-10-18

    In this paper, a type of compact nanosensor based on a metal-insulator-metal structure is proposed and investigated through cascading double asymmetric cavities, in which their metal cores shift along different axis directions. The cascaded asymmetric structure exhibits high transmission and sharp Fano resonance peaks via strengthening the mutual coupling of the cavities. The research results show that with the increase of the symmetry breaking in the structure, the number of Fano resonances increase accordingly. Furthermore, by modulating the geometrical parameters appropriately, Fano resonances with high sensitivities to the changes in refractive index can be realized. A maximum figure of merit (FoM) value of 74.3 is obtained. Considerable applications for this work can be found in bio/chemical sensors with excellent performance and other nanophotonic integrated circuit devices such as optical filters, switches and modulators.

  1. High Quality Plasmonic Sensors Based on Fano Resonances Created through Cascading Double Asymmetric Cavities

    Directory of Open Access Journals (Sweden)

    Xiangao Zhang

    2016-10-01

    Full Text Available In this paper, a type of compact nanosensor based on a metal-insulator-metal structure is proposed and investigated through cascading double asymmetric cavities, in which their metal cores shift along different axis directions. The cascaded asymmetric structure exhibits high transmission and sharp Fano resonance peaks via strengthening the mutual coupling of the cavities. The research results show that with the increase of the symmetry breaking in the structure, the number of Fano resonances increase accordingly. Furthermore, by modulating the geometrical parameters appropriately, Fano resonances with high sensitivities to the changes in refractive index can be realized. A maximum figure of merit (FoM value of 74.3 is obtained. Considerable applications for this work can be found in bio/chemical sensors with excellent performance and other nanophotonic integrated circuit devices such as optical filters, switches and modulators.

  2. Fano resonances in a high-Q terahertz whispering-gallery mode resonator coupled to a multi-mode waveguide.

    Science.gov (United States)

    Vogt, Dominik Walter; Leonhardt, Rainer

    2017-11-01

    We report on Fano resonances in a high-quality (Q) whispering-gallery mode (WGM) spherical resonator coupled to a multi-mode waveguide in the terahertz (THz) frequency range. The asymmetric line shape and phase of the Fano resonances detected with coherent continuous-wave (CW) THz spectroscopy measurements are in excellent agreement with the analytical model. A very high Q factor of 1600, and a finesse of 22 at critical coupling is observed around 0.35 THz. To the best of our knowledge this is the highest Q factor ever reported for a THz WGM resonator.

  3. Add-drop double bus microresonator array local oscillators for sharp multiple Fano resonance engineering

    Science.gov (United States)

    Li, Jiahua; Qu, Ye; Wu, Ying

    2018-03-01

    Asymmetric resonances are currently the subject of considerable research efforts in photonic nanostructures. Here we propose a feasible method to achieve multiple Fano resonances and their control in an optical compound system consisting of an array of on-chip microresonators without mutual coupling and two parallel fiber waveguides side-coupled to the microresonator array by means of a local oscillator. We derive analytical and transparent expressions for the power transmission function summing over the two light transporting paths within the framework of quantum optics. It is clearly shown that introducing the local oscillator as an additional light propagating path plays an important role in the formation of narrow and multiple Fano resonance lineshapes. The power transmission spectrum through the combination of both the microresonator array and the local oscillator is very sensitive to the system parameters, for example, the intrinsic decay rate of the resonator, the phase shift factor of the local oscillator, the transmission coefficient of the fiber beam splitter, and the total number of the microresonators. Through detailed analysis, we identify the optimums for generating Fano resonance lineshapes. Also, we assess the experimental feasibility of the scheme using currently available technology. The proposed method is relatively straightforward as it requires only one local oscillator as one interferometer arm and it is mostly fiber-based. We believe that our work will help to understand and improve multiple Fano resonance engineering.

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

    Science.gov (United States)

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

    2015-11-01

    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.

  5. Fano resonances in heterogeneous dimers of silicon and gold nanospheres

    Science.gov (United States)

    Zhao, Qian; Yang, Zhong-Jian; He, Jun

    2018-06-01

    We theoretically investigate the optical properties of dimers consisting of a gold nanosphere and a silicon nanosphere. The absorption spectrum of the gold sphere in the dimer can be significantly altered and exhibits a pronounced Fano profile. Analytical Mie theory and numerical simulations show that the Fano profile is induced by constructive and destructive interference between the incident electric field and the electric field of the magnetic dipole mode of the silicon sphere in a narrow wavelength range. The effects of the silicon sphere size, distance between the two spheres, and excitation configuration on the optical responses of the dimers are studied. Our study reveals the coherent feature of the electric fields of magnetic dipole modes in dielectric nanostructures and the strong interactions of the coherent fields with other nanophotonic structures.

  6. Multiple electromechanically-induced-transparency windows and Fano resonances in hybrid nano-electro-optomechanics

    Science.gov (United States)

    Ullah, Kamran; Jing, Hui; Saif, Farhan

    2018-03-01

    We show multiple electromechanically-induced transparency (EMIT) windows in a hybrid nano-electro-optomechanical system in the presence of two-level atoms coupled to a single-mode cavity field. The multiple EMIT-window profile can be observed by controlling the atom field coupling as well as Coulomb coupling between the two charged mechanical resonators. We derive the analytical expression of the multiple-EMIT-windows profile and describe the splitting of multiple EMIT windows as a function of optomechanical coupling, atom-field coupling, and Coulomb coupling. In particular, we discuss the robustness of the system against the cavity decay rate. We compare the results of identical mechanical resonators to different mechanical resonators. We further show how the hybrid nano-electro-optomechanics coupled system can lead to the splitting of the multiple Fano resonances (MFR). The Fano resonances are very sensitive to decay terms in such systems, i.e., atoms, cavities, and the mechanical resonators.

  7. Ambiguous Refractive Index Sensitivity of Fano Resonance on an Array of Gold Nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Špačková, Barbora; Lebrušková, Petra; Šípová, Hana; Kwiecien, P.; Richter, I.; Homola, Jiří

    2014-01-01

    Roč. 9, č. 4 (2014), s. 729-735 ISSN 1557-1955 R&D Projects: GA ČR GBP205/12/G118; GA MŠk(CZ) LH11102 Institutional support: RVO:67985882 Keywords : Island film theory * Fano resonance * Nanoparticle array Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.238, year: 2014

  8. Conversion between EIT and Fano spectra in a microring-Bragg grating coupled-resonator system

    Science.gov (United States)

    Zhang, Zecen; Ng, Geok Ing; Hu, Ting; Qiu, Haodong; Guo, Xin; Wang, Wanjun; Rouifed, Mohamed Saïd; Liu, Chongyang; Wang, Hong

    2017-08-01

    A conversion between the electromagnetically induced transparency (EIT) transmission and Fano transmission is theoretically and experimentally demonstrated in an all-pass microring-Bragg grating (APMR-BG) coupled-resonator system. In this work, the coupling between the two resonators (the microring resonator and the Fabry-Perot resonator formed by two Bragg gratings) gives rise to the EIT and Fano transmissions. The resonant status strongly depends on the round-trip attenuation of the microring and the coupling strength. By tuning the coupling strength, the EIT and Fano transmissions can be controlled and converted. The device performance has been theoretically calculated and analyzed with a specially developed numerical model based on the transfer matrix method. The APMR-BG coupled-resonator systems with different gap widths were designed, fabricated, and characterized on a silicon-on-insulator (SOI) platform. The conversion of resonance was experimentally observed and verified. In addition, this on-chip system has the advantage of a small footprint, and the fabrication process is compatible with the planar waveguide fabrication process.

  9. Spatial effects of Fano resonance in local tunneling conductivity in vicinity of impurity on semiconductor surface

    OpenAIRE

    Mantsevich, V. N.; Maslova, N. S.

    2009-01-01

    We present the results of local tunneling conductivity spatial distribution detailed theoretical investigations in vicinity of impurity atom for a wide range of applied bias voltage. We observed Fano resonance in tunneling conductivity resulting from interference between resonant tunneling channel through impurity energy level and direct tunneling channel between the tunneling contact leads. We have found that interference between tunneling channels strongly modifies form of tunneling conduct...

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

    Science.gov (United States)

    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.

  11. 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

    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-defi...... 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.......-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...

  12. 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.

  13. Multiple Fano-Like MIM Plasmonic Structure Based on Triangular Resonator for Refractive Index Sensing.

    Science.gov (United States)

    Jankovic, Nikolina; Cselyuszka, Norbert

    2018-01-19

    In this paper, we present a Fano metal-insulator-metal (MIM) structure based on an isosceles triangular cavity resonator for refractive index sensing applications. Due to the specific feeding scheme and asymmetry introduced in the triangular cavity, the resonator exhibits four sharp Fano-like resonances. The behavior of the structure is analyzed in detail and its sensing capabilities demonstrated through the responses for various refractive indices. The results show that the sensor has very good sensitivity and maximal figure of merit (FOM) value of 3.2 × 10⁵. In comparison to other similar sensors, the proposed one has comparable sensitivity and significantly higher FOM, which clearly demonstrates its high sensing potential.

  14. Polarization and angle independent magneto-electric Fano resonance in multilayer hetero-nanoshells

    Science.gov (United States)

    Wang, Wudeng; Xiong, Li; Zheng, Li; Li, Wei; Shi, Ying; Qi, Jianguang

    2018-05-01

    In this work, we have demonstrated that the Si-SiO2 -Au multilayer hetero-nanoshells can support the polarization and angle independent magneto-electric Fano resonance. Such Fano resonance arises from the direct destructive interference between the orthogonal electric dipole mode of Au core and magnetic dipole mode of the Si shell and is independent of the angle due to the high structural symmetry. In contrast to metal particle arrays, here is a possibility to generate controllable interaction between the electric and magnetic dipole resonances of individual nanoshell with the structural features. The discrete magnetic responses provided directly by the Si shell pave the groundwork for designing the magnetic responses at optical frequencies and enable many fascinating applications in nanophotonics.

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

    KAUST Repository

    Amin, Muhammad Ruhul; Bagci, Hakan

    2012-01-01

    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

  16. Electromagnetically induced reflectance and Fano resonance in one dimensional superconducting photonic crystal

    Science.gov (United States)

    Athe, Pratik; Srivastava, Sanjay; Thapa, Khem B.

    2018-04-01

    In the present work, we demonstrate the generation of optical Fano resonance and electromagnetically induced reflectance (EIR) in one-dimensional superconducting photonic crystal (1D SPC) by numerical simulation using transfer matrix method as analysis tool. We investigated the optical response of 1D SPC structure consisting of alternate layer of two different superconductors and observed that the optical spectra of this structure exhibit two narrow reflectance peaks with zero reflectivity of sidebands. Further, we added a dielectric cap layer to this 1D SPC structure and found that addition of dielectric cap layer transforms the line shape of sidebands around the narrow reflectance peaks which leads to the formation of Fano resonance and EIR line shape in reflectance spectra. We also studied the effects of the number of periods, refractive index and thickness of dielectric cap layer on the lineshape of EIR and Fano resonances. It was observed that the amplitude of peak reflectance of EIR achieves 100% reflectance by increasing the number of periods.

  17. Tunable Fano resonator using multilayer graphene in the near-infrared region

    Science.gov (United States)

    Zhou, Chaobiao; Liu, Guoqin; Ban, Guoxun; Li, Shiyu; Huang, Qingzhong; Xia, Jinsong; Wang, Yi; Zhan, Mingsheng

    2018-03-01

    Fano resonance (FR) holds promising applications for high performance optoelectronic devices due to its strong enhancement of light-matter interactions. In this work, we experimentally demonstrate a tunable FR in a photonic crystal nanoresonator (PCR), including the effects of structural parameters and graphene nanosheets with different layer numbers. The results show that the intensity and position of Fano peaks can be tuned via altering the lattice constant and the hole radius of PCR due to the variation of the effective refractive index. More importantly, we experimentally study the interaction between sharp FR with multilayer graphene. The results indicate that the FR transmission spectrum can be efficiently adjusted with the layer number of graphene, and the largest change in transmission (˜44%) is achieved with three-layer graphene because of high conductivity. These consequences may lead to efficient and tunable electro-optical modulators, biosensors, and optical switches in the near-infrared region.

  18. Experimental demonstration of a Fano laser based on photonic crystals

    DEFF Research Database (Denmark)

    Yu, Yi; Semenova, Elizaveta; Yvind, Kresten

    2017-01-01

    Conventional semiconductor laser mirrors are based on Fresnel reflection [1], Bragg reflection [2, 3] or total internal reflection [4]. Here we demonstrate a new laser concept using photonic crystals (PhC), with a mirror based on Fano interference between a waveguide continuum and a discrete...... resonance of a nanocavity [5]. We show that the very narrowband feature of the Fano resonance [6] can lead to single mode lasing. In addition, when combined with optical nonlinearity, the highly dispersive feature of the Fano resonance can promote self-pulsations at gigahertz frequencies [7], which...

  19. 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.

  20. 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.

  1. 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.

  2. Enhancement and tunability of Fano resonance in symmetric multilayer metamaterials at optical regime

    International Nuclear Information System (INIS)

    Cao, Tun; Zhang, Lei; Xiao, Zai-peng; Huang, Hui

    2013-01-01

    Fano resonance (FR) is routinely observed in three-dimensional symmetric metamaterials (MMs) consisting of elliptical nanoholes array (ENA) embedding through metal–dielectric–metal (MDM) multilayers. It is shown theoretically that a square periodic ENA perforating through MDM layers produces an FR response in the near infrared regime. This FR response is attributed to the interplay between the bright modes and dark modes, where the bright modes originate from the electric resonance (localized surface plasmon resonance) caused by the ENA and the dark modes are due to the magnetic resonance (inductive–capacitive resonance) induced by the MDM multilayers. Notably, one can achieve a narrower FR when the elliptical nanoholes occupy the sites of a rectangular lattice, owing to the interaction of the magnetic resonances with the enhanced electric resonances. Moreover, a higher varying degree of the lattice constant along the horizontal direction allows for an FR with a higher value of the quality factor and the tuning of the amplitude and the resonant frequency of the transparency window. Such an FR created by the interference among the magnetic and electric dipolar resonances opens up an alternative way of forming a sharp FR in the symmetric multilayer MMs, and could be exploited for sensing. (paper)

  3. Tunable Fano resonance in MDM stub waveguide coupled with a U-shaped cavity

    Science.gov (United States)

    Yi, Xingchun; Tian, Jinping; Yang, Rongcao

    2018-04-01

    A new compact metal-dielectric-metal waveguide system consisting of a stub coupled with a U-cavity is proposed to produce sharp and asymmetric Fano resonance. The transmission properties of the proposed structure are numerically studied by the finite element method and verified by the coupled mode theory. Simulation results reveal that the spectral profile can be easily tuned by adjusting the geometric parameters of the structure. One of the potential application of the proposed structure as a highly efficient plasmonic refractive index nanosensor was investigated with its sensitivity of more than 1000 nm/RIU and a figure of merit of up to 5500. Another application is integrated slow-light device whose group index can be greater than 6. In addition, multiple Fano resonances will occur in the broadband transmission spectrum by adding another U-cavity or (and) stub. The characteristics of the proposed structure are very promising for the highly performance filters, on-chip nanosensors, and slow-light devices.

  4. 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)

  5. 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.

  6. A perfect Fresnel acoustic reflector implemented by a Fano-resonant metascreen

    KAUST Repository

    Amin, M.

    2018-04-10

    We propose a perfectly reflecting acoustic metasurface which is designed by replacing the curved segments of the traditional Fresnel reflector by flat Fano-resonant sub-wavelength unit cells. To preserve the original Fresnel focusing mechanism, the unit cell phase follows a specific phase profile which is obtained by applying the generalized Snell\\'s law and Fermat\\'s principle. The reflected curved phase fronts are thus created at the air-metasurface boundary by tailoring the metasurface dispersion as dictated by Huygens\\' principle. Since the unit cells are implemented by sub-wavelength double slit-shaped cavity resonators, the impinging sound waves are perfectly reflected producing acoustic focusing with negligible absorption. We use plane-wave solution and full-wave simulations to demonstrate the focusing effects. The simulation results closely follow the analytical predictions.

  7. A perfect Fresnel acoustic reflector implemented by a Fano-resonant metascreen

    KAUST Repository

    Amin, M.; Siddiqui, O.; Farhat, Mohamed; Khelif, A.

    2018-01-01

    We propose a perfectly reflecting acoustic metasurface which is designed by replacing the curved segments of the traditional Fresnel reflector by flat Fano-resonant sub-wavelength unit cells. To preserve the original Fresnel focusing mechanism, the unit cell phase follows a specific phase profile which is obtained by applying the generalized Snell's law and Fermat's principle. The reflected curved phase fronts are thus created at the air-metasurface boundary by tailoring the metasurface dispersion as dictated by Huygens' principle. Since the unit cells are implemented by sub-wavelength double slit-shaped cavity resonators, the impinging sound waves are perfectly reflected producing acoustic focusing with negligible absorption. We use plane-wave solution and full-wave simulations to demonstrate the focusing effects. The simulation results closely follow the analytical predictions.

  8. 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.

  9. 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.

  10. A perfect Fresnel acoustic reflector implemented by a Fano-resonant metascreen

    Science.gov (United States)

    Amin, M.; Siddiqui, O.; Farhat, M.; Khelif, A.

    2018-04-01

    We propose a perfectly reflecting acoustic metasurface which is designed by replacing the curved segments of the traditional Fresnel reflector by flat Fano-resonant sub-wavelength unit cells. To preserve the original Fresnel focusing mechanism, the unit cell phase follows a specific phase profile which is obtained by applying the generalized Snell's law and Fermat's principle. The reflected curved phase fronts are thus created at the air-metasurface boundary by tailoring the metasurface dispersion as dictated by Huygens' principle. Since the unit cells are implemented by sub-wavelength double slit-shaped cavity resonators, the impinging sound waves are perfectly reflected producing acoustic focusing with negligible absorption. We use plane-wave solution and full-wave simulations to demonstrate the focusing effects. The simulation results closely follow the analytical predictions.

  11. Scattering of electromagnetic pulses by metal nanospheres in the vicinity of a Fano-like resonance

    International Nuclear Information System (INIS)

    Astapenko, V.A.; Svita, S.Yu.

    2015-01-01

    In the work, radiation scattering by metal nanospheres in a dielectric matrix in case of ultrashort and long electromagnetic pulses is studied theoretically. Spectral efficiencies of backward and forward scattering by silver nanospheres in glass are calculated with the use of experimental data on the dielectric permittivity of silver. The presence of Fano-like resonances in spectral dependences of scattering efficiency caused by interference of dipole and quadrupole scatterings is shown. Backward and forward scattering of ultrashort pulses is calculated and analyzed. The obtained dependences of the total probability of scattering (during all time of the action of a pulse) on pulse duration demonstrate an essential distinction between an ultrashort case and a long pulse limit

  12. 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.

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

    International Nuclear Information System (INIS)

    Nguyen Bich Ha; Nguyen Van Hop

    2009-01-01

    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.

  14. Ultra-narrow band perfect absorbers based on Fano resonance in MIM metamaterials

    Science.gov (United States)

    Zhang, Ming; Fang, Jiawen; Zhang, Fei; Chen, Junyan; Yu, Honglin

    2017-12-01

    Metallic nanostructures have attracted numerous attentions in the past decades due to their attractive plasmonic properties. Resonant plasmonic perfect absorbers have promising applications in a wide range of technologies including photothermal therapy, thermophotovoltaics, heat-assisted magnetic recording and biosensing. However, it remains to be a great challenge to achieve ultra-narrow band in near-infrared band with plasmonic materials due to the large optical losses in metals. In this letter, we introduced Fano resonance in MIM metamaterials composed of an asymmetry double elliptic cylinders (ADEC), which can achieve ultra-narrow band perfect absorbers. In theoretical calculations, we observed an ultranarrow band resonant absorption peak with the full width at half maximum (FWHM) of 8 nm and absorption amplitude exceeding 99% at 930 nm. Moreover, we demonstrate that the absorption increases with the increase of asymmetry and the absorption resonant wavelength can be tuned by changing the size and arrangement of the unit cell. The asymmetry metallic nanostructure also exhibit a higher refractive sensitivity as large as 503 nm/RIU with high figure of merit of 63, which is promising for high sensitive sensors. Results of this work are desirable for various potential applications in micro-technological structures such as biological sensors, narrowband emission, photodetectors and solar thermophotovoltaic (STPV) cells.

  15. Coupled-mode theory and Fano resonances in guided-mode resonant gratings: the conical diffraction mounting.

    Science.gov (United States)

    Bykov, Dmitry A; Doskolovich, Leonid L; Soifer, Victor A

    2017-01-23

    We study resonances of guided-mode resonant gratings in conical mounting. By developing 2D time-dependent coupled-mode theory we obtain simple approximations of the transmission and reflection coefficients. Being functions of the incident light's frequency and in-plane wave vector components, the obtained approximations can be considered as multi-variable generalizations of the Fano line shape. We show that the approximations are in good agreement with the rigorously calculated transmission and reflection spectra. We use the developed theory to investigate angular tolerances of the considered structures and to obtain mode excitation conditions. In particular, we obtain the cross-polarization mode excitation conditions in the case of conical mounting.

  16. 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

    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...

  17. Sensing performance analysis on Fano resonance of metallic double-baffle contained MDM waveguide coupled ring resonator

    Science.gov (United States)

    Chen, Ying; Luo, Pei; Liu, Xiaofei; Di, Yuanjian; Han, Shuaitao; Cui, Xingning; He, Lei

    2018-05-01

    Based on the transmission property and the photon localization characteristic of the surface plasmonic sub-wavelength structure, a metallic double-baffle contained metal-dielectric-metal (MDM) waveguide coupled ring resonator is proposed. Like the electromagnetically induced transparency (EIT), the Fano resonance can be achieved by the interference between the metallic double-baffle resonator and the ring resonator. Based on the coupled mode theory, the transmission property is analyzed. Through the numerical simulation by the finite element method (FEM), the quantitative analysis on the influences of the radius R of the ring and the coupling distance g between the metallic double-baffle resonator and the ring resonator for the figure of merit (FOM) is performed. And after the structure parameter optimization, the sensing performance of the waveguide structure is discussed. The simulation results show that the FOM value of the optimized structure can attain to 5.74 ×104 and the sensitivity of resonance wavelength with refractive index drift is about 825 nm/RIU. The range of the detected refractive index is suitable for all gases. The waveguide structure can provide effective theoretical references for the design of integrated plasmonic devices.

  18. Theoretical study of high-Q Fano resonance and extrinsic chirality in an ultrathin Babinet-inverted metasurface

    Science.gov (United States)

    Wang, Feng; Wang, Zhengping; Shi, Jinhui

    2014-10-01

    A high-Q Fano resonance and giant extrinsic chirality have been demonstrated in an ultrathin Babinet-inverted metasurface composed of asymmetrical split ring apertures (ASRAs) perforated through a metal plate based on the full-wave simulations. The performance of the Fano resonance at normal incidence strongly depends on the asymmetry of the ASRA. The quality factor is larger than 1000 and the local field enhancement is an order of 104. For oblique incidence, giant extrinsic chirality can be achieved in the Babinet-inverted metasurface. It reveals a cross-polarization transmission band with a ripple-free peak and also a spectrum split for large angles of incidence. The electromagnetic response of the metasurface can be easily tuned via angles of incidence and asymmetry. The proposed ASRA metasurface is of importance to develop many metamaterial-based devices, such as filters and circular polarizers.

  19. 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.

  20. Nonlinear elasticity in resonance experiments

    Science.gov (United States)

    Li, Xun; Sens-Schönfelder, Christoph; Snieder, Roel

    2018-04-01

    Resonant bar experiments have revealed that dynamic deformation induces nonlinearity in rocks. These experiments produce resonance curves that represent the response amplitude as a function of the driving frequency. We propose a model to reproduce the resonance curves with observed features that include (a) the log-time recovery of the resonant frequency after the deformation ends (slow dynamics), (b) the asymmetry in the direction of the driving frequency, (c) the difference between resonance curves with the driving frequency that is swept upward and downward, and (d) the presence of a "cliff" segment to the left of the resonant peak under the condition of strong nonlinearity. The model is based on a feedback cycle where the effect of softening (nonlinearity) feeds back to the deformation. This model provides a unified interpretation of both the nonlinearity and slow dynamics in resonance experiments. We further show that the asymmetry of the resonance curve is caused by the softening, which is documented by the decrease of the resonant frequency during the deformation; the cliff segment of the resonance curve is linked to a bifurcation that involves a steep change of the response amplitude when the driving frequency is changed. With weak nonlinearity, the difference between the upward- and downward-sweeping curves depends on slow dynamics; a sufficiently slow frequency sweep eliminates this up-down difference. With strong nonlinearity, the up-down difference results from both the slow dynamics and bifurcation; however, the presence of the bifurcation maintains the respective part of the up-down difference, regardless of the sweep rate.

  1. Electronic and transport properties of noncollinear magnetic monatomic Mn chains: Fano resonances in the superlattice of noncollinear magnetic barriers and magnetic anisotropic bands

    International Nuclear Information System (INIS)

    Dai, C.J.; Yan, X.H.; Xiao, Y.; Guo, Y.D.

    2015-01-01

    By means of the density functional theory combined with non-equilibrium Green's function method, ballistic transport properties of one-dimensional noncollinear magnetic monatomic chains were investigated using the single-atomic Mn chains as a model system. Fano resonances are found to exist in the monatomic Mn chains with spin-spiral structure. Furthermore, in the monatomic Mn chains with magnetic soliton lattice, Fano resonances are enhanced and cause the conductance splitting in the transmission spectra. The Fano resonances in the noncollinear magnetic single-atomic Mn chains are arising from the coupling of the localized d-states and the extended states of the quantum channels. By constructing a theoretical model and calculating its conductance, it is found that the phenomena of Fano resonances and the accompanying conductance splitting exist universally in the superlattice of one-dimensional noncollinear magnetic barriers, due to the interference of the incident waves and reflected waves by the interfaces between the neighboring barriers. Moreover, the band structures of the ferromagnetic and spin-spiral monatomic Mn chains exhibit a strong dependence on the spatial arrangement of the magnetic moments of Mn atoms when spin–orbit coupling is considered. - Highlights: • Transport properties of noncollinear magnetic monatomic Mn chains are studied. • Fano resonances are found in the noncollinear magnetic monatomic Mn chains. • Magnetic soliton lattice leads to conductance splitting in the transmission curve. • Fano resonances exist in the superlattice of noncollinear magnetic barriers. • Effect of SOC on the band structure of FM and spin-spiral Mn chains are studied

  2. Nonlinear phenomena at cyclotron resonance

    International Nuclear Information System (INIS)

    Subbarao, D.; Uma, R.

    1986-01-01

    Finite amplitude electromagnetic waves in a magnetoplasma which typically occur in situations as in present day wave heating, current drives and other schemes in magnetically confined fusion systems, can show qualitatively different absorption and emission characteristics around resonant frequencies of the plasma because of anharmonicity. Linear wave plasma coupling as well as weak nonlinear effects such as parametric instabilities generally overlook this important effect even though the thresholds for the two phenomena as shown here are comparable. Though the effects described here are relevant to a host of nonlinear resonance effects in fusion plasmas, the authors mainly limit themselves to ECRH

  3. Nonlinear Dynamics of Nanomechanical Resonators

    Science.gov (United States)

    Ramakrishnan, Subramanian; Gulak, Yuiry; Sundaram, Bala; Benaroya, Haym

    2007-03-01

    Nanoelectromechanical systems (NEMS) offer great promise for many applications including motion and mass sensing. Recent experimental results suggest the importance of nonlinear effects in NEMS, an issue which has not been addressed fully in theory. We report on a nonlinear extension of a recent analytical model by Armour et al [1] for the dynamics of a single-electron transistor (SET) coupled to a nanomechanical resonator. We consider the nonlinear resonator motion in both (a) the Duffing and (b) nonlinear pendulum regimes. The corresponding master equations are derived and solved numerically and we consider moment approximations as well. In the Duffing case with hardening stiffness, we observe that the resonator is damped by the SET at a significantly higher rate. In the cases of softening stiffness and the pendulum, there exist regimes where the SET adds energy to the resonator. To our knowledge, this is the first instance of a single model displaying both negative and positive resonator damping in different dynamical regimes. The implications of the results for SET sensitivity as well as for, as yet unexplained, experimental results will be discussed. 1. Armour et al. Phys.Rev.B (69) 125313 (2004).

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

    DEFF Research Database (Denmark)

    Yu, Yi; Xue, Weiqi; Semenova, Elizaveta

    2017-01-01

    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......, that nonlinearities in the mirror may even promote the generation of a self-sustained train of pulses at gigahertz frequencies, an effect that has previously been observed only in macroscopic lasers(15-18). Such a source is of interest for a number of applications within integrated photonics....

  5. Fano resonance in the absorption of two photons in crystal defects. Ressonancia de Fano na absorcao de dois fotons em defeitos cristalinos

    Energy Technology Data Exchange (ETDEWEB)

    Souza, G P

    1984-01-01

    The absorption of two photons in the electronic transition within the 4f/sup 7/ configuration which is superposed to the vibronic structure of the 4f/sup 7/ - 4f/sup 6/5d transition, is studied. The line shape with the Fano's formalism is described. The study was carried out on Eu/sup +2/ doped CaF/sub 2/. The experimental apparatus was built and the results obtained are in good agreement with the theoretical predictions.

  6. Imaging Plasmon Hybridization of Fano Resonances via Hot-Electron-Mediated Absorption Mapping.

    Science.gov (United States)

    Simoncelli, Sabrina; Li, Yi; Cortés, Emiliano; Maier, Stefan A

    2018-05-04

    The inhibition of radiative losses in dark plasmon modes allows storing electromagnetic energy more efficiently than in far-field excitable bright-plasmon modes. As such, processes benefiting from the enhanced absorption of light in plasmonic materials could also take profit of dark plasmon modes to boost and control nanoscale energy collection, storage, and transfer. We experimentally probe this process by imaging with nanoscale precision the hot-electron driven desorption of thiolated molecules from the surface of gold Fano nanostructures, investigating the effect of wavelength and polarization of the incident light. Spatially resolved absorption maps allow us to show the contribution of each element of the nanoantenna in the hot-electron driven process and their interplay in exciting a dark plasmon mode. Plasmon-mode engineering allows control of nanoscale reactivity and offers a route to further enhance and manipulate hot-electron driven chemical reactions and energy-conversion and transfer at the nanoscale.

  7. Noise in nonlinear nanoelectromechanical resonators

    Science.gov (United States)

    Guerra Vidal, Diego N.

    Nano-Electro-Mechanical Systems (NEMS), due to their nanometer scale size, possess a number of desirable attributes: high sensitivity to applied forces, fast response times, high resonance frequencies and low power consumption. However, ultra small size and low power handling result in unwanted consequences: smaller signal size and higher dissipation, making the NEMS devices more susceptible to external and intrinsic noise. The simplest version of a NEMS, a suspended nanomechanical structure with two distinct excitation states, can be used as an archetypal two state system to study a plethora of fundamental phenomena such as Duffing nonlinearity, stochastic resonance, and macroscopic quantum tunneling at low temperatures. From a technical perspective, there are numerous applications such nanomechanical memory elements, microwave switches and nanomechanical computation. The control and manipulation of the mechanical response of these two state systems can be realized by exploiting a (seemingly) counterintuitive physical phenomenon, Stochastic Resonance: in a noisy nonlinear mechanical system, the presence of noise can enhance the system response to an external stimulus. This Thesis is mainly dedicated to study possible applications of Stochastic Resonance in two-state nanomechanical systems. First, on chip signal amplification by 1/falpha is observed. The effectiveness of the noise assisted amplification is observed to decrease with increasing a. Experimental evidence shows an increase in asymmetry between the two states with increasing noise color. Considering the prevalence of 1/f alpha noise in the materials in integrated circuits, the signal enhancement demonstrated here, suggests beneficial use of the otherwise detrimental noise. Finally, a nanomechanical device, operating as a reprogrammable logic gate, and performing fundamental logic functions such as AND/OR and NAND/NOR is presented. The logic function can be programmed (from AND to OR) dynamically, by

  8. 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.)

  9. Nonlinear plasma waves excited near resonance

    International Nuclear Information System (INIS)

    Cohen, B.I.; Kaufman, A.N.

    1977-01-01

    The nonlinear resonant response of a uniform plasma to an external plane-wave field is formulated in terms of the mismatch Δ/sub n l/ between the driving frequency and the time-dependent, complex, nonlinear normal mode frequency at the driving wavenumber. This formalism is applied to computer simulations of this process, yielding a deduced nonlinear frequency shift. The time dependence of the nonlinear phenomena, at frequency Δ/sub n l/ and at the bounce frequency of the resonant particles, is analyzed. The interdependence of the nonlinear features is described by means of energy and momentum relations

  10. 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

  11. 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.

  12. Tunable Resonators for Nonlinear Modal Interactions

    KAUST Repository

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

    2016-01-01

    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.

  13. Bidirectional waveguide coupling with plasmonic Fano nanoantennas

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Rui; Decker, Manuel, E-mail: manuel.decker@anu.edu.au; Staude, Isabelle; Neshev, Dragomir N.; Kivshar, Yuri S. [Nonlinear Physics Centre and Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS), Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia)

    2014-08-04

    We introduce the concept of a bidirectional, compact single-element Fano nanoantenna that allows for directional coupling of light in opposite directions of a high-index dielectric waveguide for two different operation wavelengths. We utilize a Fano resonance to tailor the radiation phases of a gold nanodisk and a nanoslit that is inscribed into the nanodisk to realize bidirectional scattering. We show that this Fano nanoantenna operates as a bidirectional waveguide coupler at telecommunication wavelengths and, thus, is ideally suitable for integrated wavelength-selective light demultiplexing.

  14. Dynamic beam cleaning by a nonlinear resonance

    Energy Technology Data Exchange (ETDEWEB)

    Chao, A W; Month, M [Brookhaven National Lab., Upton, N.Y. (USA)

    1976-03-15

    The general framework for the dynamic cleaning of a stored proton beam by passing the beam through a nonlinear resonance is developed. The limitations and advantages of this technique are discussed. The method is contrasted with physical beam scraping, which is currently in use at the CERN ISR.

  15. Nonlinear effects in varactor-tuned resonators.

    Science.gov (United States)

    Everard, Jeremy; Zhou, Liang

    2006-05-01

    This paper describes the effects of RF power level on the performance of varactor-tuned resonator circuits. A variety of topologies are considered, including series and parallel resonators operating in both unbalanced and balanced modes. As these resonators were designed to produce oscillators with minimum phase noise, the initial small signal insertion loss was set to 6 dB and, hence, QL/Q0 = 1/2. To enable accurate analysis and simulation, S parameter and PSPICE models for the varactors were optimized and developed. It is shown that these resonators start to demonstrate nonlinear operation at very low power levels demonstrating saturation and lowering of the resonant frequency. On occasion squegging is observed for modified bias conditions. The nonlinear effects are dependent on the unloaded Q (Q0), the ratio of loaded to unloaded Q (QL/Q0), the bias voltage, and circuit configurations with typical nonlinear effects occurring at -8 dBm in a circuit with a loaded Q of 63 and a varactor bias voltage of 3 V. Analysis, simulation, and measurements that show close correlation are presented.

  16. Resonant driving of a nonlinear Hamiltonian system

    International Nuclear Information System (INIS)

    Palmisano, Carlo; Gervino, Gianpiero; Balma, Massimo; Devona, Dorina; Wimberger, Sandro

    2013-01-01

    As a proof of principle, we show how a classical nonlinear Hamiltonian system can be driven resonantly over reasonably long times by appropriately shaped pulses. To keep the parameter space reasonably small, we limit ourselves to a driving force which consists of periodic pulses additionally modulated by a sinusoidal function. The main observables are the average increase of kinetic energy and of the action variable (of the non-driven system) with time. Applications of our scheme aim for driving high frequencies of a nonlinear system with a fixed modulation signal.

  17. Partial pseudospin polarization, latticetronics and Fano resonances in quantum dots based in graphene ribbons: a conductance spectroscopy

    Science.gov (United States)

    López, Luis I. A.; Champi, Ana; Ujevic, Sebastian; Mendoza, Michel

    2015-11-01

    In this work we study, as a function of the height V and width L b of the potential barriers, the transport of Dirac quasi-particles through quantum dots in graphene ribbons. We observed, as we increase V, a partial polarization ( PP) of the pseudospin due to the participation of the hyperbolic bands. This generates polarizations in the sub-lattices A or B outside the dot regions for single, coupled, and open dots. Thus for energies around the Dirac point, the conductance G at both sides of the dot shows a latticetronics of conductances G A and G B as a function of V and L b . This fact can be used as a PP spectroscopy which associates hole-type waves with the latticetronics. A periodic enhancement of PP is obtained with the increase of V in dots formed by barriers that completely occupy the nanoribbon width. For this case, a direct correspondence between G( V) and PP( V) exists. On the other hand, for the open dots, the PP( V) and the G( V) show a complex behavior that exhibit higher intensities when compared to the previous case. In the Dirac limit we have no backscattering signs, however when we move slightly away from this limit the first signs of confinement appear in the PP( V) (it freezes in a given sub-lattice). In the last case the backscattering fingerprints are obtained directly from the conductance (splittings). The open quantum dots are very sensible to their opening w d and this generates Fano line-shapes of difficult interpretation around the Dirac point. The PP spectroscopy used here allows us to understand the influence of w d in the relativistic analogues and to associate electron-type waves with the observed Fano line-shapes.

  18. Nonlinear relativistic plasma resonance: Renormalization group approach

    Energy Technology Data Exchange (ETDEWEB)

    Metelskii, I. I., E-mail: metelski@lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Kovalev, V. F., E-mail: vfkvvfkv@gmail.com [Dukhov All-Russian Research Institute of Automatics (Russian Federation); Bychenkov, V. Yu., E-mail: bychenk@lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2017-02-15

    An analytical solution to the nonlinear set of equations describing the electron dynamics and electric field structure in the vicinity of the critical density in a nonuniform plasma is constructed using the renormalization group approach with allowance for relativistic effects of electron motion. It is demonstrated that the obtained solution describes two regimes of plasma oscillations in the vicinity of the plasma resonance— stationary and nonstationary. For the stationary regime, the spatiotemporal and spectral characteristics of the resonantly enhanced electric field are investigated in detail and the effect of the relativistic nonlinearity on the spatial localization of the energy of the plasma relativistic field is considered. The applicability limits of the obtained solution, which are determined by the conditions of plasma wave breaking in the vicinity of the resonance, are established and analyzed in detail for typical laser and plasma parameters. The applicability limits of the earlier developed nonrelativistic theories are refined.

  19. Nonlinear nuclear magnetic resonance in ferromagnets

    International Nuclear Information System (INIS)

    Nurgaliev, T.

    1988-01-01

    The properties of nonlinear nuclear magnetic resonance (NMR) have been studied theoretically by taking into account the interaction between NMR and FMR in the ferromagnets. The Landau-Lifshitz-Bloch equations, describing the electron and nuclear magnetization behaviour in ferromagnets are presented in an integral form for a weakly excited electronic system. The stationary solution of these equations has been analysed in the case of equal NMR and FMR frequencies: the criteria for the appearance of two stable dynamic states is found and the high-frequency magnetic susceptibility for these systems is investigated. 2 figs., 8 refs

  20. 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)

  1. 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.

  2. Nonlinearity in superconducting titanium nitride coplanar waveguide resonators

    International Nuclear Information System (INIS)

    Neilinger, P.; Trgala, M.; Hrebikova, I.; Mikula, M.; Zahoran, M.; Truchly, M.; Grajcar, M.; Leporis, M.

    2012-01-01

    In this paper we present fabrication and characterization of superconducting CPW TiN resonator at 20 and 300 nm film thickness. Further we demonstrate strong nonlinearity in thin TiN resonators. (authors)

  3. 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.

  4. Direct Imaging of Transient Fano Resonances in N_{2} Using Time-, Energy-, and Angular-Resolved Photoelectron Spectroscopy.

    Science.gov (United States)

    Eckstein, Martin; Yang, Chung-Hsin; Frassetto, Fabio; Poletto, Luca; Sansone, Giuseppe; Vrakking, Marc J J; Kornilov, Oleg

    2016-04-22

    Autoionizing Rydberg states of molecular N_{2} are studied using time-, energy-, and angular-resolved photoelectron spectroscopy. A femtosecond extreme ultraviolet pulse with a photon energy of 17.5 eV excites the resonance and a subsequent IR pulse ionizes the molecule before the autoionization takes place. The angular-resolved photoelectron spectra depend on pump-probe time delay and allow for the distinguishing of two electronic states contributing to the resonance. The lifetime of one of the contributions is determined to be 14±1  fs, while the lifetime of the other appears to be significantly shorter than the time resolution of the experiment. These observations suggest that the Rydberg states in this energy region are influenced by the effect of interference stabilization and merge into a complex resonance.

  5. Nonlinear behaviour of cantilevered carbon nanotube resonators based on a new nonlinear electrostatic load model

    Science.gov (United States)

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

    2018-04-01

    The present study examines the nonlinear behaviour of a cantilevered carbon nanotube (CNT) resonator and its mass detection sensitivity, employing a new nonlinear electrostatic load model. More specifically, a 3D finite element model is developed in order to obtain the electrostatic load distribution on cantilevered CNT resonators. A new nonlinear electrostatic load model is then proposed accounting for the end effects due to finite length. Additionally, a new nonlinear size-dependent continuum model is developed for the cantilevered CNT resonator, employing the modified couple stress theory (to account for size-effects) together with the Kelvin-Voigt model (to account for nonlinear damping); the size-dependent model takes into account all sources of nonlinearity, i.e. geometrical and inertial nonlinearities as well as nonlinearities associated with damping, small-scale, and electrostatic load. The nonlinear equation of motion of the cantilevered CNT resonator is obtained based on the new models developed for the CNT resonator and the electrostatic load. The Galerkin method is then applied to the nonlinear equation of motion, resulting in a set of nonlinear ordinary differential equations, consisting of geometrical, inertial, electrical, damping, and size-dependent nonlinear terms. This high-dimensional nonlinear discretized model is solved numerically utilizing the pseudo-arclength continuation technique. The nonlinear static and dynamic responses of the system are examined for various cases, investigating the effect of DC and AC voltages, length-scale parameter, nonlinear damping, and electrostatic load. Moreover, the mass detection sensitivity of the system is examined for possible application of the CNT resonator as a nanosensor.

  6. Spectra of resonance surface photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Antsiferov, V.V.; Smirnov, G.I.; Telegin, G.G. [Budker Nuclear Physics Institute, Novosibirsk (Russian Federation)

    1995-09-01

    The theory of nonactivated electron transfer between atoms interacting reasonantly with coherent radiation and a metal surface is developed. The spectral resonances in photoabsorption and surface photoionization are found to be related to nonlinear interference effects in the interaction between discrete atomic levels and the continuum formed by the quasi-continuous electron spectrum of a normal metal. The asymmetry in the resonance surface photoionization spectrum is shown to have a shape typical of the Fano autoionization resonances. 18 refs.

  7. Nonlinear resonance in Duffing oscillator with fixed and integrative ...

    Indian Academy of Sciences (India)

    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 ...

  8. Nonlinear resonance in Duffing oscillator with fixed and integrative ...

    Indian Academy of Sciences (India)

    2012-03-02

    Mar 2, 2012 ... Abstract. 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 α and the ...

  9. Classification of smooth Fano polytopes

    DEFF Research Database (Denmark)

    Øbro, Mikkel

    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...... 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 ....

  10. Resonant Column Tests and Nonlinear Elasticity in Simulated Rocks

    Science.gov (United States)

    Sebastian, Resmi; Sitharam, T. G.

    2018-01-01

    Rocks are generally regarded as linearly elastic even though the manifestations of nonlinearity are prominent. The variations of elastic constants with varying strain levels and stress conditions, disagreement between static and dynamic moduli, etc., are some of the examples of nonlinear elasticity in rocks. The grain-to-grain contact, presence of pores and joints along with other compliant features induce the nonlinear behavior in rocks. The nonlinear elastic behavior of rocks is demonstrated through resonant column tests and numerical simulations in this paper. Resonant column tests on intact and jointed gypsum samples across varying strain levels have been performed in laboratory and using numerical simulations. The paper shows the application of resonant column apparatus to obtain the wave velocities of stiff samples at various strain levels under long wavelength condition, after performing checks and incorporating corrections to the obtained resonant frequencies. The numerical simulation and validation of the resonant column tests using distinct element method are presented. The stiffness reductions of testing samples under torsional and flexural vibrations with increasing strain levels have been analyzed. The nonlinear elastic behavior of rocks is reflected in the results, which is enhanced by the presence of joints. The significance of joint orientation and influence of joint spacing during wave propagation have also been assessed and presented using the numerical simulations. It has been found that rock joints also exhibit nonlinear behavior within the elastic limit.

  11. 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.

  12. Nonlinear Ion Harmonics in the Paul Trap with Added Octopole Field: Theoretical Characterization and New Insight into Nonlinear Resonance Effect.

    Science.gov (United States)

    Xiong, Caiqiao; Zhou, Xiaoyu; Zhang, Ning; Zhan, Lingpeng; Chen, Yongtai; Nie, Zongxiu

    2016-02-01

    The nonlinear harmonics within the ion motion are the fingerprint of the nonlinear fields. They are exclusively introduced by these nonlinear fields and are responsible to some specific nonlinear effects such as nonlinear resonance effect. In this article, the ion motion in the quadrupole field with a weak superimposed octopole component, described by the nonlinear Mathieu equation (NME), was studied by using the analytical harmonic balance (HB) method. Good accuracy of the HB method, which was comparable with that of the numerical fourth-order Runge-Kutta (4th RK), was achieved in the entire first stability region, except for the points at the stability boundary (i.e., β = 1) and at the nonlinear resonance condition (i.e., β = 0.5). Using the HB method, the nonlinear 3β harmonic series introduced by the octopole component and the resultant nonlinear resonance effect were characterized. At nonlinear resonance, obvious resonant peaks were observed in the nonlinear 3β series of ion motion, but were not found in the natural harmonics. In addition, both resonant excitation and absorption peaks could be observed, simultaneously. These are two unique features of the nonlinear resonance, distinguishing it from the normal resonance. Finally, an approximation equation was given to describe the corresponding working parameter, q nr , at nonlinear resonance. This equation can help avoid the sensitivity degradation due to the operation of ion traps at the nonlinear resonance condition.

  13. 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.

  14. Nonlinear Resonance Analysis of Slender Portal Frames under Base Excitation

    Directory of Open Access Journals (Sweden)

    Luis Fernando Paullo Muñoz

    2017-01-01

    Full Text Available The dynamic nonlinear response and stability of slender structures in the main resonance regions are a topic of importance in structural analysis. In complex problems, the determination of the response in the frequency domain indirectly obtained through analyses in time domain can lead to huge computational effort in large systems. In nonlinear cases, the response in the frequency domain becomes even more cumbersome because of the possibility of multiple solutions for certain forcing frequencies. Those solutions can be stable and unstable, in particular saddle-node bifurcation at the turning points along the resonance curves. In this work, an incremental technique for direct calculation of the nonlinear response in frequency domain of plane frames subjected to base excitation is proposed. The transformation of equations of motion to the frequency domain is made through the harmonic balance method in conjunction with the Galerkin method. The resulting system of nonlinear equations in terms of the modal amplitudes and forcing frequency is solved by the Newton-Raphson method together with an arc-length procedure to obtain the nonlinear resonance curves. Suitable examples are presented, and the influence of the frame geometric parameters and base motion on the nonlinear resonance curves is investigated.

  15. Nonlinear resonance islands and modulational effects in a proton synchrotron

    International Nuclear Information System (INIS)

    Satogata, T.J.

    1993-01-01

    The authors examine one-dimensional and two-dimensional nonlinear resonance islands created in the transverse phase space of a proton synchrotron by nonlinear magnets. The authors 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, the authors 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 parameters: The strength and frequency of the modulation and the frequency of small oscillations inside the resonance island. The tune modulation model is 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 examined in two transverse dimensions in the presence of coupling and linearly independent crossing resonances. The authors present a first-order Hamiltonian model which predicts fixed point locations, but does not reproduce small oscillation frequencies seen in tracking. Particle tracking is presented which shows evidence of two-dimensional persistent signals, and the authors make suggestions on methods for observing such signals in future experiment. The authors apply the tune modulation stability diagram to the explicitly two-dimensional phenomenon of modulational diffusion in the Fermilab Tevatron with beam-beam kicks as the source of nonlinearity. The amplitude growth created by this mechanism in simulation is exponential rather than root-time as predicted by modulational diffusion models. The authors comment upon the luminosity and lifetime limitations such a mechanism implies in a proton storage ring

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

    OpenAIRE

    Tuz, Vladimir R.; Kochetov, Bogdan A.; 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 l...

  17. Comparison of stochastic resonance in static and dynamical nonlinearities

    International Nuclear Information System (INIS)

    Ma, Yumei; Duan, Fabing

    2014-01-01

    We compare the stochastic resonance (SR) effects in parallel arrays of static and dynamical nonlinearities via the measure of output signal-to-noise ratio (SNR). For a received noisy periodic signal, parallel arrays of both static and dynamical nonlinearities can enhance the output SNR by optimizing the internal noise level. The static nonlinearity is easily implementable, while the dynamical nonlinearity has more parameters to be tuned, at the risk of not exploiting the beneficial role of internal noise components. It is of interest to note that, for an input signal buried in the external Laplacian noise, we show that the dynamical nonlinearity is superior to the static nonlinearity in obtaining a better output SNR. This characteristic is assumed to be closely associated with the kurtosis of noise distribution. - Highlights: • Comparison of SR effects in arrays of both static and dynamical nonlinearities. • Static nonlinearity is easily implementable for the SNR enhancement. • Dynamical nonlinearity yields a better output SNR for external Laplacian noise

  18. Nonlinear dynamics in micromechanical and nanomechanical resonators and oscillators

    Science.gov (United States)

    Dunn, Tyler

    In recent years, the study of nonlinear dynamics in microelectromechanical and nanoelectromechanical systems (MEMS and NEMS) has attracted considerable attention, motivated by both fundamental and practical interests. One example is the phenomenon of stochastic resonance. Previous measurements have established the presence of this counterintuitive effect in NEMS, showing that certain amounts of white noise can effectively amplify weak switching signals in nanomechanical memory elements and switches. However, other types of noise, particularly noises with 1/falpha spectra, also bear relevance in these and many other systems. At a more fundamental level, the role which noise color plays in stochastic resonance remains an open question in the field. To these ends, this work presents systematic measurements of stochastic resonance in a nanomechanical resonator using 1/f alpha and Ornstein-Uhlenbeck noise types. All of the studied noise spectra induce stochastic resonance, proving that colored noise can also be beneficial; however, stronger noise correlations suppress the effect, decreasing the maximum signal-to-noise ratio and increasing the optimal noise intensity. Evidence suggests that 1/falpha noise spectra with increasing noise color lead to increasingly asymmetric switching, reducing the achievable amplification. Another manifestly nonlinear effect anticipated in these systems is modal coupling. Measurements presented here demonstrate interactions between various mode types on a wide scale, providing the first reported observations of coupling in bulk longitudinal modes of MEMS. As a result of anharmonic elastic effects, each mode shifts in frequency by an amount proportional to the squared displacement (or energy) of a coupled mode. Since all resonator modes couple in this manner, these effects enable nonlinear measurement of energy and mechanical nonlinear signal processing across a wide range of frequencies. Finally, while these experiments address nonlinear

  19. Tables of Shore and Fano parameters for the helium resonances 2s21S, 2p21D, and 2s 2p 1P excited in p-He collisions E/sub p/ = 33 to 150 keV

    International Nuclear Information System (INIS)

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

    1976-01-01

    Absolute values of Shore and Fano parameters are tabulated for the helium atom 2s 2 1 S, 2p 2 1 D, and 2s 2p 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 0

  20. 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.

  1. Nonlinear Dynamics of Silicon Nanowire Resonator Considering Nonlocal Effect.

    Science.gov (United States)

    Jin, Leisheng; Li, Lijie

    2017-12-01

    In this work, nonlinear dynamics of silicon nanowire resonator considering nonlocal effect has been investigated. For the first time, dynamical parameters (e.g., resonant frequency, Duffing coefficient, and the damping ratio) that directly influence the nonlinear dynamics of the nanostructure have been derived. Subsequently, by calculating their response with the varied nonlocal coefficient, it is unveiled that the nonlocal effect makes more obvious impacts at the starting range (from zero to a small value), while the impact of nonlocal effect becomes weaker when the nonlocal term reaches to a certain threshold value. Furthermore, to characterize the role played by nonlocal effect in exerting influence on nonlinear behaviors such as bifurcation and chaos (typical phenomena in nonlinear dynamics of nanoscale devices), we have calculated the Lyapunov exponents and bifurcation diagram with and without nonlocal effect, and results shows the nonlocal effect causes the most significant effect as the device is at resonance. This work advances the development of nanowire resonators that are working beyond linear regime.

  2. Nonlinear Dynamics of a Helicopter Model in Ground Resonance

    Science.gov (United States)

    Tang, D. M.; Dowell, E. H.

    1985-01-01

    An approximate theoretical method is presented which determined the limit cycle behavior of a helicopter model which has one or two nonlinear dampers. The relationship during unstable ground resonance oscillations between lagging motion of the blades and fuselage motion is discussed. An experiment was carried out on using a helicopter scale model. The experimental results agree with those of the theoretical analysis.

  3. Nonlinear bounce resonances between magnetosonic waves and equatorially mirroring electrons

    Science.gov (United States)

    Chen, Lunjin; Maldonado, Armando; Bortnik, Jacob; Thorne, Richard M.; Li, Jinxing; Dai, Lei; Zhan, Xiaoya

    2015-08-01

    Equatorially mirroring energetic electrons pose an interesting scientific problem, since they generally cannot resonate with any known plasma waves and hence cannot be scattered down to lower pitch angles. Observationally it is well known that the flux of these equatorial particles does not simply continue to build up indefinitely, and so a mechanism must necessarily exist that transports these particles from an equatorial pitch angle of 90° down to lower values. However, this mechanism has not been uniquely identified yet. Here we investigate the mechanism of bounce resonance with equatorial noise (or fast magnetosonic waves). A test particle simulation is used to examine the effects of monochromatic magnetosonic waves on the equatorially mirroring energetic electrons, with a special interest in characterizing the effectiveness of bounce resonances. Our analysis shows that bounce resonances can occur at the first three harmonics of the bounce frequency (nωb, n = 1, 2, and 3) and can effectively reduce the equatorial pitch angle to values where resonant scattering by whistler mode waves becomes possible. We demonstrate that the nature of bounce resonance is nonlinear, and we propose a nonlinear oscillation model for characterizing bounce resonances using two key parameters, effective wave amplitude à and normalized wave number k~z. The threshold for higher harmonic resonance is more strict, favoring higher à and k~z, and the change in equatorial pitch angle is strongly controlled by k~z. We also investigate the dependence of bounce resonance effects on various physical parameters, including wave amplitude, frequency, wave normal angle and initial phase, plasma density, and electron energy. It is found that the effect of bounce resonance is sensitive to the wave normal angle. We suggest that the bounce resonant interaction might lead to an observed pitch angle distribution with a minimum at 90°.

  4. Jump resonant frequency islands in nonlinear feedback control systems

    Science.gov (United States)

    Koenigsberg, W. D.; Dunn, J. C.

    1975-01-01

    A new type of jump resonance is predicted and observed in certain nonlinear feedback control systems. The new jump resonance characteristic is described as a 'frequency island' due to the fact that a portion of the input-output transfer characteristic is disjoint from the main body. The presence of such frequency islands was predicted by using a sinusoidal describing function characterization of the dynamics of an inertial gyro employing nonlinear ternary rebalance logic. While the general conditions under which such islands are possible has not been examined, a numerical approach is presented which can aid in establishing their presence. The existence of the frequency islands predicted for the ternary rebalanced gyro was confirmed by simulating the nonlinear system and measuring the transfer function.

  5. 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.

    2015-01-01

    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. PMID:25854939

  6. Nonlinear damping of oblique whistler mode waves through Landau resonance

    Science.gov (United States)

    Hsieh, Y.; Omura, Y.

    2017-12-01

    Nonlinear trapping of electrons through Landau resonance is a characteristic dynamics in oblique whistler-mode wave particle interactions. The resonance velocity of the Landau resonance at quasi-parallel propagation becomes very close to the parallel group velocity of whistler-mode wave at frequency around 0.5 Ωe, causing a long distance of resonant interaction and strong acceleration of resonant electrons [1]. We demonstrate these effective accelerations for electrons with high equatorial pitch angle ( > 60°) by test particle simulations with parameters for the Earth's inner magnetosphere at L=5. In the simulations, we focus on slightly oblique whistler mode waves with wave normal angle 10.1002/2016JA023255.

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

    KAUST Repository

    Ilyas, Saad; Chappanda, K. N.; Younis, Mohammad I.

    2017-01-01

    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.

  8. 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.

  9. Elastic Nonlinear Response in Granular Media Under Resonance Conditions

    Science.gov (United States)

    Jia, X.; Johnson, P. A.

    2004-12-01

    We are studying the elastic linear and nonlinear behavior of granular media using dynamic wave methods. In the work presented here, our goal is to quantify the elastic nonlinear response by applying wave resonance. Resonance studies are desirable because they provide the means to easily study amplitude dependencies of elastic nonlinear behavior and thus to characterize the physical nature of the elastic nonlinearity. This work has implications for a variety of topics, in particular, the in situ nonlinear response of surface sediments. For this work we constructed an experimental cell in which high sensitivity dynamic resonance studies were conducted using granular media under controlled effective pressure. We limit our studies here to bulk modes but have the capability to employ shear waves as well. The granular media are composed of glass beads held under pressure by a piston, while applying resonance waves from transducers as both the excitation and the material probe. The container is closed with two fitted pistons and a normal load is applied to the granular sample across the top piston. Force and displacement are measured directly. Resonant frequency sweeps with frequencies corresponding to the fundamental bulk mode are applied to the longitudinal source transducer. The pore pressure in the system is 1 atm. The glass beads used in our experiments are of diameter 0.5 mm, randomly deposited in a duralumin cylinder of diameter 30 mm and height of 15 mm. This corresponds to a granular skeleton acoustic wave velocity of v ª 750m/s under 50 N of force [0.07 Mpa]. The loaded system gives fundamental mode resonances in the audio frequency band at half a wavelength where resonance frequency is effective-pressure dependent. The volume fraction of glass beads thus obtained is found to be 0.63 ± 0.01. Plane-wave generating and detecting transducers of diameter 30 mm are placed on axis at the top and bottom of the cylindrical container in direct contact with the glass

  10. Fano effect in the transport of an artificial molecule

    Science.gov (United States)

    Norimoto, Shota; Nakamura, Shuji; Okazaki, Yuma; Arakawa, Tomonori; Asano, Kenichi; Onomitsu, Koji; Kobayashi, Kensuke; Kaneko, Nobu-hisa

    2018-05-01

    The Fano effect is a ubiquitous phenomenon arising from interference between a discrete energy state and an energy continuum. We explore this effect in an artificial molecule, namely, two lateral quantum dots (QDs) fabricated from a two-dimensional electron gas system and coupled in series. When the coupling between the leads and QDs is small, the charge stability diagram of the system shows a honeycomb lattice structure that is characteristic of a double QD system. As the coupling increases, a honeycomb structure consisting of the Fano resonances emerges. A numerical simulation based on the T-matrix method can satisfactorily reproduce our experimental observation. This report constitutes a clear example of the ubiquitous nature of the Fano effect in mesoscopic transport.

  11. Parameter Identification for Nonlinear Circuit Models of Power BAW Resonator

    Directory of Open Access Journals (Sweden)

    CONSTANTINESCU, F.

    2011-02-01

    Full Text Available The large signal operation of the bulk acoustic wave (BAW resonators is characterized by the amplitude-frequency effect and the intermodulation effect. The measurement of these effects, together with that of the small signal frequency characteristic, are used in this paper for the parameter identification of the nonlinear circuit models developed previously by authors. As the resonator has been connected to the measurement bench by wire bonding, the parasitic elements of this connection have been taken into account, being estimated solving some electrical and magnetic field problems.

  12. Suppressing nonlinear resonances in an impact oscillator using SMAs

    International Nuclear Information System (INIS)

    Sitnikova, Elena; Pavlovskaia, Ekaterina; Ing, James; Wiercigroch, Marian

    2012-01-01

    In this paper, we study the resonant responses of an impact oscillator with a one sided SMA motion constraint operating in the pseudoelastic regime. The effectiveness of the SMA restraint in suppressing nonlinear resonances of the impact oscillator is assessed by comparing the dynamic responses of the impact oscillator with SMA and elastic restraints. It is shown that the hysteretic behaviour of the SMA restraint provides an overall vibration reduction in the resonant frequency ranges. Due to the softening behaviour of the SMA element, the resonant frequencies for the SMA oscillator were found to be lower than for the oscillator with an elastic restraint. At each resonance, a single periodic response for the oscillator with the elastic restraint corresponds to two co-existing periodic responses of the SMA oscillator. While at the first resonance peak the emergence of one of the co-existing responses is associated with the hardening effect of the SMA restraint when the pseudoelastic force varies over a complete transformation cycle, at higher frequency resonances incomplete phase transformations in the SMA were detected for both responses. The experimental study undertaken verified the response-modification effects predicted by the numerical analysis conducted under the isothermal approximation. The experimental results showed a good quantitative correspondence with the mathematical modelling. (paper)

  13. Nonlinear dynamics of resonant electrons interacting with coherent Langmuir waves

    Science.gov (United States)

    Tobita, Miwa; Omura, Yoshiharu

    2018-03-01

    We study the nonlinear dynamics of resonant particles interacting with coherent waves in space plasmas. Magnetospheric plasma waves such as whistler-mode chorus, electromagnetic ion cyclotron waves, and hiss emissions contain coherent wave structures with various discrete frequencies. Although these waves are electromagnetic, their interaction with resonant particles can be approximated by equations of motion for a charged particle in a one-dimensional electrostatic wave. The equations are expressed in the form of nonlinear pendulum equations. We perform test particle simulations of electrons in an electrostatic model with Langmuir waves and a non-oscillatory electric field. We solve equations of motion and study the dynamics of particles with different values of inhomogeneity factor S defined as a ratio of the non-oscillatory electric field intensity to the wave amplitude. The simulation results demonstrate deceleration/acceleration, thermalization, and trapping of particles through resonance with a single wave, two waves, and multiple waves. For two-wave and multiple-wave cases, we describe the wave-particle interaction as either coherent or incoherent based on the probability of nonlinear trapping.

  14. Fluctuation Reduction in a Si Micromechanical Resonator Tuned to Nonlinear Internal Resonance

    Science.gov (United States)

    Strachan, B. Scott; Czaplewski, David; Chen, Changyao; Dykman, Mark; Lopez, Daniel; Shaw, Steven

    2015-03-01

    We describe experimental and theoretical results on an unusual behavior of fluctuations when the system exhibits internal resonance. We study the fundamental flexural mode (FFM) of a Si microbeam. The FFM is electrically actuated and detected. It is resonantly nonlinearly coupled to another mode, which is not directly accessible and has a frequency nearly three times the FFM frequency. Both the FFM and the passive mode have long lifetimes. We find that the passive mode can be a ``sink'' for fluctuations of the FFM. This explains the recently observed dramatic decrease of these fluctuations at nonlinear resonance. The re-distribution of the vibration amplitudes and the fluctuations is reminiscent of what happens at level anti-crossing in quantum mechanics. However, here it is different because of interplay of the dependence of the vibration frequency of the FFM on its amplitude due to internal nonlinearity and the nonlinear resonance with the passive mode. We study both the response of the system to external resonant driving and also the behavior of the system in the presence of a feedback loop. The experimental and theoretical results are in good agreement.

  15. 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.

  16. The non-linear ion trap. Part 5. Nature of non-linear resonances and resonant ion ejection

    Science.gov (United States)

    Franzen, J.

    1994-01-01

    The superposition of higher order multipole fields on the basic quadrupole field in ion traps generates a non-harmonic oscillator system for the ions. Fourier analyses of simulated secular oscillations in non-linear ion traps, therefore, not only reveal the sideband frequencies, well-known from the Mathieu theory, but additionally a commonwealth of multipole-specific overtones (or higher harmonics), and corresponding sidebands of overtones. Non-linear resonances occur when the overtone frequencies match sideband frequencies. It can be shown that in each of the resonance conditions, not just one overtone matches one sideband, instead, groups of overtones match groups of sidebands. The generation of overtones is studied by Fourier analysis of computed ion oscillations in the direction of thez axis. Even multipoles (octopole, dodecapole, etc.) generate only odd orders of higher harmonics (3, 5, etc.) of the secular frequency, explainable by the symmetry with regard to the planez = 0. In contrast, odd multipoles (hexapole, decapole, etc.) generate all orders of higher harmonics. For all multipoles, the lowest higher harmonics are found to be strongest. With multipoles of higher orders, the strength of the overtones decreases weaker with the order of the harmonics. Forz direction resonances in stationary trapping fields, the function governing the amplitude growth is investigated by computer simulations. The ejection in thez direction, as a function of timet, follows, at least in good approximation, the equation wheren is the order of multipole, andC is a constant. This equation is strictly valid for the electrically applied dipole field (n = 1), matching the secular frequency or one of its sidebands, resulting in a linear increase of the amplitude. It is valid also for the basic quadrupole field (n = 2) outside the stability area, giving an exponential increase. It is at least approximately valid for the non-linear resonances by weak superpositions of all higher odd

  17. 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.

  18. 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.

  19. 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.

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

    International Nuclear Information System (INIS)

    Ma Junhai; Sun Tao; Liu Lixia

    2008-01-01

    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

  1. Nonlinear mode conversion with chaotic soliton generation at plasma resonance

    International Nuclear Information System (INIS)

    Pietsch, H.; Laedke, E.W.; Spatschek, K.H.

    1993-01-01

    The resonant absorption of electromagnetic waves near the critical density in inhomogeneous plasmas is studied. A driven nonlinear Schroedinger equation for the mode-converted oscillations is derived by multiple-scaling techniques. The model is simulated numerically. The generic transition from a stationary to a time-dependent solution is investigated. Depending on the parameters, a time-chaotic behavior is found. By a nonlinear analysis, based on the inverse scattering transform, solitons of a corresponding integrable equation are identified as the dominant coherent structures of the chaotic dynamics. Finally, a map is presented which predicts chaotic soliton generation and emission at the critical density. Its qualitative behavior, concerning the bifurcation points, is in excellent agreement with the numerical simulations

  2. Formalism of photons in a nonlinear microring resonator

    Science.gov (United States)

    Tran, Quang Loc; Yupapin, Preecha

    2018-03-01

    In this paper, using short Gaussian pulses input from a monochromatic light source, we simulate the photon distribution and analyse the output gate's signals of PANDA nonlinear ring resonator. The present analysis is restricted to directional couplers characterized by two parameters, the power coupling coefficient κ and power coupling loss γ. Add/drop filters are also employed and investigated for the suitable to implement in the practical communication system. The experiment was conducted by using the combination of Lumerical FDTD Solutions and Lumerical MODE Solutions software.

  3. Nonlinear resonance ultrasonic vibrations in Czochralski-silicon wafers

    Science.gov (United States)

    Ostapenko, S.; Tarasov, I.

    2000-04-01

    A resonance effect of generation of subharmonic acoustic vibrations is observed in as-grown, oxidized, and epitaxial silicon wafers. Ultrasonic vibrations were generated into a standard 200 mm Czochralski-silicon (Cz-Si) wafer using a circular ultrasound transducer with major frequency of the radial vibrations at about 26 kHz. By tuning frequency (f) of the transducer within a resonance curve, we observed a generation of intense f/2 subharmonic acoustic mode assigned as a "whistle." The whistle mode has a threshold amplitude behavior and narrow frequency band. The whistle is attributed to a nonlinear acoustic vibration of a silicon plate. It is demonstrated that characteristics of the whistle mode are sensitive to internal stress and can be used for quality control and in-line diagnostics of oxidized and epitaxial Cz-Si wafers.

  4. Simulation Analysis of Helicopter Ground Resonance Nonlinear Dynamics

    Science.gov (United States)

    Zhu, Yan; Lu, Yu-hui; Ling, Ai-min

    2017-07-01

    In order to accurately predict the dynamic instability of helicopter ground resonance, a modeling and simulation method of helicopter ground resonance considering nonlinear dynamic characteristics of components (rotor lead-lag damper, landing gear wheel and absorber) is presented. The numerical integral method is used to calculate the transient responses of the body and rotor, simulating some disturbance. To obtain quantitative instabilities, Fast Fourier Transform (FFT) is conducted to estimate the modal frequencies, and the mobile rectangular window method is employed in the predictions of the modal damping in terms of the response time history. Simulation results show that ground resonance simulation test can exactly lead up the blade lead-lag regressing mode frequency, and the modal damping obtained according to attenuation curves are close to the test results. The simulation test results are in accordance with the actual accident situation, and prove the correctness of the simulation method. This analysis method used for ground resonance simulation test can give out the results according with real helicopter engineering tests.

  5. 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.

  6. 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/.

  7. Fano-Andreev effect in Quantum Dots in Kondo regime

    Science.gov (United States)

    Orellana, Pedro; Calle, Ana Maria; Pacheco, Monica; Apel, Victor

    In the present work, we investigate the transport through a T-shaped double quantum dot system coupled to two normal leads and to a superconducting lead. We study the role of the superconducting lead in the quantum interferometric features of the double quantum dot and by means of a slave boson mean field approximation at low temperature regime. We inquire into the influence of intradot interactions in the electronic properties of the system as well. Our results show that Fano resonances due to Andreev bound states are exhibited in the transmission from normal to normal lead as a consequence of quantum interference and proximity effect. This Fano effect produced by Andreev bound states in a side quantum dot was called Fano-Andreev effect, which remains valid even if the electron-electron interaction are taken into account, that is, the Fano-Andreev effect is robust against e-e interactions even in Kondo regime. We acknowledge the financial support from FONDECYT program Grants No. 3140053 and 11400571.

  8. Wave propagation in a strongly nonlinear locally resonant granular crystal

    Science.gov (United States)

    Vorotnikov, K.; Starosvetsky, Y.; Theocharis, G.; Kevrekidis, P. G.

    2018-02-01

    In this work, we study the wave propagation in a recently proposed acoustic structure, the locally resonant granular crystal. This structure is composed of a one-dimensional granular crystal of hollow spherical particles in contact, containing linear resonators. The relevant model is presented and examined through a combination of analytical approximations (based on ODE and nonlinear map analysis) and of numerical results. The generic dynamics of the system involves a degradation of the well-known traveling pulse of the standard Hertzian chain of elastic beads. Nevertheless, the present system is richer, in that as the primary pulse decays, secondary ones emerge and eventually interfere with it creating modulated wavetrains. Remarkably, upon suitable choices of parameters, this interference "distills" a weakly nonlocal solitary wave (a "nanopteron"). This motivates the consideration of such nonlinear structures through a separate Fourier space technique, whose results suggest the existence of such entities not only with a single-side tail, but also with periodic tails on both ends. These tails are found to oscillate with the intrinsic oscillation frequency of the out-of-phase motion between the outer hollow bead and its internal linear attachment.

  9. Nonlinear Plasma Response to Resonant Magnetic Perturbation in Rutherford Regime

    Science.gov (United States)

    Zhu, Ping; Yan, Xingting; Huang, Wenlong

    2017-10-01

    Recently a common analytic relation for both the locked mode and the nonlinear plasma response in the Rutherford regime has been developed based on the steady-state solution to the coupled dynamic system of magnetic island evolution and torque balance equations. The analytic relation predicts the threshold and the island size for the full penetration of resonant magnetic perturbation (RMP). It also rigorously proves a screening effect of the equilibrium toroidal flow. In this work, we test the theory by solving for the nonlinear plasma response to a single-helicity RMP of a circular-shaped limiter tokamak equilibrium with a constant toroidal flow, using the initial-value, full MHD simulation code NIMROD. Time evolution of the parallel flow or ``slip frequency'' profile and its asymptotic approach to steady state obtained from the NIMROD simulations qualitatively agree with the theory predictions. Further comparisons are carried out for the saturated island size, the threshold for full mode penetration, as well as the screening effects of equilibrium toroidal flow in order to understand the physics of nonlinear plasma response in the Rutherford regime. Supported by National Magnetic Confinement Fusion Science Program of China Grants 2014GB124002 and 2015GB101004, the 100 Talent Program of the Chinese Academy of Sciences, and U.S. Department of Energy Grants DE-FG02-86ER53218 and DE-FC02-08ER54975.

  10. Dispersive shock mediated resonant radiations in defocused nonlinear medium

    Science.gov (United States)

    Bose, Surajit; Chattopadhyay, Rik; Bhadra, Shyamal Kumar

    2018-04-01

    We report the evolution of resonant radiation (RR) in a self-defocused nonlinear medium with two zero dispersion wavelengths. RR is generated from dispersive shock wave (DSW) front when the pump pulse is in non-solitonic regime close to first zero dispersion wavelength (ZDW). DSW is responsible for pulse splitting resulting in the generation of blue solitons when leading edge of the pump pulse hits the first ZDW. DSW also generates a red shifted dispersive wave (DW) in the presence of higher order dispersion coefficients. Further, DSW through cross-phase modulation with red shifted dispersive wave (DW) excites a localized radiation. The presence of zero nonlinearity point in the system restricts red-shift of RR and enhances the red shifting of DW. It also helps in the formation of DSW at shorter distance and squeezes the solitonic region beyond second zero dispersion point. Predicted results indicate that the spectral evolution depends on the product of Kerr nonlinearity and group velocity dispersion.

  11. 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 piezoelectric...... was excited at different frequencies. Different excitation signals were generated using a linear power amplifier and a multilevel converter within a range of 30–200 V. Empirical relation was developed to express the resistance of the piezoelectric transducer as a nonlinear function of both excitation voltage...... and resonance frequency. The impedance measurements revealed that at higher voltage ranges, the piezoelectric transducer can be easily saturated. Also, it was shown that for the developed ultrasound system composed of two transducers (one transmitter and one receiver), the output voltage measured across...

  12. Theoretical and experimental nonlinear dynamics of a clamped-clamped beam MEMS resonator

    NARCIS (Netherlands)

    Mestrom, R.M.C.; Fey, R.H.B.; Nijmeijer, H.

    2008-01-01

    Microelectromechanical resonators feature nonlineardynamic responses. A first-principles based modeling approach is proposed for a clamped-clamped beam resonator. Starting from the partial differential equation for the beam including geometric and electrostatic nonlinear effects, a reduced-order

  13. Particle trapping by nonlinear resonances and space charge

    International Nuclear Information System (INIS)

    Franchetti, G.; Hofmann, I.

    2006-01-01

    In the FAIR [C.D.R. http://www.gsi.de/GSI Future/cdr/] facility planned at GSI high space charge effects and nonlinear dynamics may play an important role for limiting nominal machine performance. The most relevant interplay of these two effects on the single particle dynamics has been proposed in terms of trapping of particles into stable islands [G. Franchetti, I. Hofmann, AIP Conf. Proc. 642 (2002) 260]. Subsequent numerical studies and dedicated experiments have followed [G. Franchetti et al., Phys. Rev. ST Accel. Beams 6 (2003) 124201; G. Franchetti et al., AIP Conf. Proc. 773 (2005) 137]. We present here the effect of the chromaticity on the mechanisms of halo formation induced by particle trapping into resonances

  14. Nonlinear stability, bifurcation and resonance in granular plane Couette flow

    Science.gov (United States)

    Shukla, Priyanka; Alam, Meheboob

    2010-11-01

    A weakly nonlinear stability theory is developed to understand the effect of nonlinearities on various linear instability modes as well as to unveil the underlying bifurcation scenario in a two-dimensional granular plane Couette flow. The relevant order parameter equation, the Landau-Stuart equation, for the most unstable two-dimensional disturbance has been derived using the amplitude expansion method of our previous work on the shear-banding instability.ootnotetextShukla and Alam, Phys. Rev. Lett. 103, 068001 (2009). Shukla and Alam, J. Fluid Mech. (2010, accepted). Two types of bifurcations, Hopf and pitchfork, that result from travelling and stationary linear instabilities, respectively, are analysed using the first Landau coefficient. It is shown that the subcritical instability can appear in the linearly stable regime. The present bifurcation theory shows that the flow is subcritically unstable to disturbances of long wave-lengths (kx˜0) in the dilute limit, and both the supercritical and subcritical states are possible at moderate densities for the dominant stationary and traveling instabilities for which kx=O(1). We show that the granular plane Couette flow is prone to a plethora of resonances.ootnotetextShukla and Alam, J. Fluid Mech. (submitted, 2010)

  15. A novel nonlinear damage resonance intermodulation effect for structural health monitoring

    Science.gov (United States)

    Ciampa, Francesco; Scarselli, Gennaro; Meo, Michele

    2017-04-01

    This paper is aimed at developing a theoretical model able to predict the generation of nonlinear elastic effects associated to the interaction of ultrasonic waves with the steady-state nonlinear response of local defect resonance (LDR). The LDR effect is used in nonlinear elastic wave spectroscopy to enhance the excitation of the material damage at its local resonance, thus to dramatically increase the vibrational amplitude of material nonlinear phenomena. The main result of this work is to prove both analytically and experimentally the generation of novel nonlinear elastic wave effects, here named as nonlinear damage resonance intermodulation, which correspond to a nonlinear intermodulation between the driving frequency and the LDR one. Beside this intermodulation effect, other nonlinear elastic wave phenomena such as higher harmonics of the input frequency and superharmonics of LDR frequency were found. The analytical model relies on solving the nonlinear equation of motion governing bending displacement under the assumption of both quadratic and cubic nonlinear defect approximation. Experimental tests on a damaged composite laminate confirmed and validated these predictions and showed that using continuous periodic excitation, the nonlinear structural phenomena associated to LDR could also be featured at locations different from the damage resonance. These findings will provide new opportunities for material damage detection using nonlinear ultrasounds.

  16. Nonlinear resonance and dynamical chaos in a diatomic molecule driven by a resonant ir field

    International Nuclear Information System (INIS)

    Berman, G.P.; Bulgakov, E.N.; Holm, D.D.

    1995-01-01

    We consider the transition from regular motion to dynamical chaos in a classical model of a diatomic molecule which is driven by a circularly polarized resonant ir field. Under the conditions of a nearly two-dimensional case, the Hamiltonian reduces to that for the nonintegrable motion of a charged particle in an electromagnetic wave [A. J. Lichtenberg and M. A. Lieberman, Regular and Stochastic Motion (Springer-Verlag, City, 1983)]. In the general case, the transition to chaos is connected with the overlapping of vibrational-rotational nonlinear resonances and appears even at rather low radiation field intensity, S approx-gt 1 GW/cm 2 . We also discuss the possibility of experimentally observing this transition

  17. 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.

  18. Unbounded Perturbations of Nonlinear Second-Order Difference Equations at Resonance

    Directory of Open Access Journals (Sweden)

    Ma Ruyun

    2007-01-01

    Full Text Available We study the existence of solutions of nonlinear discrete boundary value problems , , , where is the first eigenvalue of the linear problem , , , satisfies some “asymptotic nonuniform” resonance conditions, and for .

  19. 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.

  20. 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.

  1. Dynamic analysis of optical soliton pair and four-wave mixing via Fano interference in multiple quantum wells

    International Nuclear Information System (INIS)

    Yan, Wei; Qu, Junle; Niu, H B

    2014-01-01

    We perform a time-dependent analysis of the formation and stable propagation of an ultraslow optical soliton pair, and four-wave mixing (FWM) via tunable Fano interference in double-cascade type semiconductor multiple quantum wells (SMQWs). By using the probability amplitude method to describe the interaction of the system, we demonstrate that the electromagnetically induced transparency (EIT) can be controlled by Fano interference in the linear case and the strength of Fano interference has an important effect on the group velocity and amplitude of the soliton pair in the nonlinear case. Then, when the signal field is removed, the dynamic FWM process is analyzed in detail, and we find that the strength of Fano interference also has an important effect on the FWM’s efficiency: the maximum FWM efficiency is ∼28% in appropriate conditions. The investigations are promising for practical applications in optical devices and optical information processing for solid systems. (paper)

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

    KAUST Repository

    Amin, Muhammad; Farhat, Mohamed; Bagci, Hakan

    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.

  3. Effects of error feedback on a nonlinear bistable system with stochastic resonance

    International Nuclear Information System (INIS)

    Li Jian-Long; Zhou Hui

    2012-01-01

    In this paper, we discuss the effects of error feedback on the output of a nonlinear bistable system with stochastic resonance. The bit error rate is employed to quantify the performance of the system. The theoretical analysis and the numerical simulation are presented. By investigating the performances of the nonlinear systems with different strengths of error feedback, we argue that the presented system may provide guidance for practical nonlinear signal processing

  4. Engineering non-linear resonator mode interactions in circuit QED by continuous driving: Introduction

    Science.gov (United States)

    Pfaff, Wolfgang; Reagor, Matthew; Heeres, Reinier; Ofek, Nissim; Chou, Kevin; Blumoff, Jacob; Leghtas, Zaki; Touzard, Steven; Sliwa, Katrina; Holland, Eric; Krastanov, Stefan; Frunzio, Luigi; Devoret, Michel; Jiang, Liang; Schoelkopf, Robert

    2015-03-01

    High-Q microwave resonators show great promise for storing and manipulating quantum states in circuit QED. Using resonator modes as such a resource in quantum information processing applications requires the ability to manipulate the state of a resonator efficiently. Further, one must engineer appropriate coupling channels without spoiling the coherence properties of the resonator. We present an architecture that combines millisecond lifetimes for photonic quantum states stored in a linear resonator with fast measurement provided by a low-Q readout resonator. We demonstrate experimentally how a continuous drive on a transmon can be utilized to generate highly non-classical photonic states inside the high-Q resonator via effective nonlinear resonator mode interactions. Our approach opens new avenues for using modes of long-lived linear resonators in the circuit QED platform for quantum information processing tasks.

  5. Balanced line bundles on Fano varieties

    DEFF Research Database (Denmark)

    Lehmann, Brian; Tanimoto, Sho; Tschinkel, Yuri

    2018-01-01

    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....

  6. In memorium: Ugo Fano (1912-2001)

    International Nuclear Information System (INIS)

    Inokuti, M.

    2001-01-01

    With the passing of Ugo Fano on 13 February 2001, the Radiation Research Society lost an influential founding member. A broader community dearly misses a great theoretical physicist. Ugo Fano was born a son of Rosa Cassin and Gino Fano (1871-1952), professor of mathematics at Turin, Italy, specializing in differential geometry. Having studied mathematics first at the University of Turin, the younger Fano turned to physics under the influence of his cousin, Giulio Racah (1909-1965), a physicist known for the powerful theory of angular momentum. Then Fano was fortunate to receive postdoctoral training from two giants in modern physics: Enrico Fermi at Rome in 1934-1936 and Werner Heisenberg at Leipzig in 1936-1937. Fano's American career began with pioneering work in 1940-1944 in what was later to be called radiation biology with M. Demerec and others at the Department of Genetics of the Carnegie Institution at Cold Spring Harbor. It is noteworthy that, after a seminar in Rome by P. Jordan on the effects of X rays on genetic material, Fermi had suggested to Fano that the biological action of radiation would be an important and suitable topic for study. Fano's papers in this period concerned chromosomal rearrangements, mutations, lethal effects, and genetic effects of X rays and neutrons on Drosophila melanogaster, as well as theoretical analysis of genetic data. His work also included the discovery of bacteriophage-resistant mutants in Escherichia coli, following up earlier studies by Salvador E. Luria. After a wartime effort at the U.S. Army Ballistic Research Laboratory in 1944-1945, Fano joined the staff of the National Bureau of Standards in 1946. Fano's two decades at NBS saw prolific and outstanding contributions to two major areas of research: radiation physics and the basic physics of atoms, molecules and condensed matter. Many of Fano's contributions to radiation physics are seminal to later developments. In 1946, he put forth the first general theory of the

  7. Ultrasensitive mass sensing with nonlinear optics in a doubly clamped suspended carbon nanotube resonator

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hua-Jun; Zhu, Ka-Di [Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 DongChuan Road, Shanghai 2 00240 (China)

    2013-12-07

    Nanomechanical resonator makes itself as an ideal system for ultrasensitive mass sensing due to its ultralow mass and high vibrational frequency. The mass sensing principle is due to the linear relationship of the frequency-shift and mass-variation. In this work, we will propose a nonlinear optical mass sensor based on a doubly clamped suspended carbon nanotube resonator in all-optical domain. The masses of external particles (such as nitric oxide molecules) landing onto the surface of carbon nanotube can be determined directly and accurately via using the nonlinear optical spectroscopy. This mass sensing proposed here may provide a nonlinear optical measurement technique in quantum measurements and environmental science.

  8. Estimation of Fano factor in inorganic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Bora, Vaibhav, E-mail: bora.vaibhav@gmail.com [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Barrett, Harrison H., E-mail: barrett@radiology.arizona.edu [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Fastje, David, E-mail: dfastje@gmail.com [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Clarkson, Eric, E-mail: clarkson@radiology.arizona.edu [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Furenlid, Lars, E-mail: furen@radiology.arizona.edu [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Bousselham, Abdelkader, E-mail: abousselham@qf.org.qa [Qatar Foundation, QEERI, P.O. Box 5825, Doha (Qatar); Shah, Kanai S., E-mail: kanaishah@yahoo.com [Radiation Monitoring Devices, Inc., Watertown, MA 02472 (United States); Glodo, Jarek, E-mail: jglodo@rmdinc.com [Radiation Monitoring Devices, Inc., Watertown, MA 02472 (United States)

    2016-01-01

    The Fano factor of an integer-valued random variable is defined as the ratio of its variance to its mean. Correlation between the outputs of two photomultiplier tubes on opposite faces of a scintillation crystal was used to estimate the Fano factor of photoelectrons and scintillation photons. Correlations between the integrals of the detector outputs were used to estimate the photoelectron and photon Fano factor for YAP:Ce, SrI{sub 2}:Eu and CsI:Na scintillator crystals. At 662 keV, SrI{sub 2}:Eu was found to be sub-Poisson, while CsI:Na and YAP:Ce were found to be super-Poisson. An experiment setup inspired from the Hanbury Brown and Twiss experiment was used to measure the correlations as a function of time between the outputs of two photomultiplier tubes looking at the same scintillation event. A model of the scintillation and the detection processes was used to generate simulated detector outputs as a function of time for different values of Fano factor. The simulated outputs from the model for different Fano factors was compared to the experimentally measured detector outputs to estimate the Fano factor of the scintillation photons for YAP:Ce, LaBr{sub 3}:Ce scintillator crystals. At 662 keV, LaBr{sub 3}:Ce was found to be sub-Poisson, while YAP:Ce was found to be close to Poisson.

  9. Fano effect and Andreev bound states in T-shape double quantum dots

    International Nuclear Information System (INIS)

    Calle, A.M.; Pacheco, M.; Orellana, P.A.

    2013-01-01

    In this Letter, we investigate the transport through a T-shaped double quantum dot coupled to two normal metal leads left and right and a superconducting lead. Analytical expressions of Andreev transmission and local density of states of the system at zero temperature have been obtained. We study the role of the superconducting lead in the quantum interferometric features of the double quantum dot. We report for first time the Fano effect produced by Andreev bound states in a side quantum dot. Our results show that as a consequence of quantum interference and proximity effect, the transmission from normal to normal lead exhibits Fano resonances due to Andreev bound states. We find that this interference effect allows us to study the Andreev bound states in the changes in the conductance between two normal leads. - Highlights: • Transport properties of a double quantum dot coupled in T-shape configuration to conducting and superconducting leads are studied. • We report Fano antiresonances in the normal transmission due to the Andreev reflections in the superconducting lead. • We report for first time the Fano effect produced by Andreev bound states in a side quantum dot. • Fano effect allows us to study the Andreev bound states in the changes in the conductance between two normal leads. • Andreev bound states survives even for strong dot-superconductor coupling

  10. 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.

  11. Fano-induced spontaneous emission enhancement of molecule placed in a cluster of asymmetrically-arranged metallic nanoparticles

    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, MN 55812 (United States); Bai, Jing [Department of Electrical Engineering, University of Minnesota, Duluth, MN 55812 (United States); Nguyen, H.P.T. [Department of Electrical and Computer Engineering, New Jersey Institute of Technology, NJ 07102 (United States)

    2016-05-15

    We demonstrate that plasmonic Fano resonance significantly boosts spontaneous emission rate of a single emitter, e.g. atom, molecule and quantum dot, over a moderately broad emission spectrum. An emission enhancement of up to 140 times compared to the system with no external inclusion at tunable frequencies is achieved, providing a new complementary enhancement mechanism. Fano resonance is induced in clusters of four asymmetric-arranged nanoparticles with ultra-small inter-particle gaps. It is shown to play a dominant role in light-emitting enhancement, mediated by combined localized surface plasmon resonances.

  12. Nonlinear resonance phenomena of a doped fibre laser under cavity ...

    Indian Academy of Sciences (India)

    quence and other routes to chaos, generalized multistability and crisis. But, doped ... of chaos and synchronization of coupled chaotic lasers (for communication with a ... The two basic issues in focus here for the nonlinear dynamical studies.

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

    KAUST Repository

    Ruzziconi, Laura; Bataineh, Ahmad M.; Younis, Mohammad I.; Cui, Weili; Lenci, Stefano

    2013-01-01

    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

  14. Nonlinear resonant ultrasound spectroscopy (NRUS) applied to damage assessment in bone

    Science.gov (United States)

    Muller, Marie; Sutin, Alexander; Guyer, Robert; Talmant, Maryline; Laugier, Pascal; Johnson, Paul A.

    2005-12-01

    Nonlinear resonant ultrasound spectroscopy (NRUS) is a resonance-based technique exploiting the significant nonlinear behavior of damaged materials. In NRUS, the resonant frequency(ies) of an object is studied as a function of the excitation level. As the excitation level increases, the elastic nonlinearity is manifest by a shift in the resonance frequency. This study shows the feasibility of this technique for application to damage assessment in bone. Two samples of bovine cortical bone were subjected to progressive damage induced by application of mechanical cycling. Before cycling commenced, and at each step in the cycling process, NRUS was applied for damage assessment. For independent assessment of damage, high-energy x-ray computed tomography imaging was performed but was only useful in identifying the prominent cracks. As the integral quantity of damage increased, NRUS revealed a corresponding increase in the nonlinear response. The measured change in nonlinear response is much more sensitive than the change in linear modulus. The results suggest that NRUS could be a potential tool for micro-damage assessment in bone. Further work must be carried out for a better understanding of the physical nature of damaged bone and for the ultimate goal of the challenging in vivo implementation of the technique.

  15. Self-excited nonlinear plasma series resonance oscillations in geometrically symmetric capacitively coupled radio frequency discharges

    International Nuclear Information System (INIS)

    Donko, Z.; Schulze, J.; Czarnetzki, U.; Luggenhoelscher, D.

    2009-01-01

    At low pressures, nonlinear self-excited plasma series resonance (PSR) oscillations are known to drastically enhance electron heating in geometrically asymmetric capacitively coupled radio frequency discharges by nonlinear electron resonance heating (NERH). Here we demonstrate via particle-in-cell simulations that high-frequency PSR oscillations can also be excited in geometrically symmetric discharges if the driving voltage waveform makes the discharge electrically asymmetric. This can be achieved by a dual-frequency (f+2f) excitation, when PSR oscillations and NERH are turned on and off depending on the electrical discharge asymmetry, controlled by the phase difference of the driving frequencies

  16. Nonlinear cyclotron-resonance accelerations by a generalized EM wave

    International Nuclear Information System (INIS)

    Akimoto, K.; Hojo, H.

    2004-01-01

    Particle accelerations by a one-dimensional, electromagnetic, dispersive pulse in an external magnetic field are investigated. It is found that the well-known cyclotron resonance may be classified into three regimes as the length and/or the amplitude of the pulse are varied. Namely, as the pulse amplitude increases, the transit-time cyclotron-resonance acceleration (CRA) evolves to phase trapping, and reflect particles. The amplitude and wave dispersion as well as the pulse length strongly affect those accelerations. The interesting phenomena of quantization of resonance velocities in between the two regimes are also investigated. This new mechanism may lead to wave amplification at some discrete frequencies other than the cyclotron frequency. (authors)

  17. 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.

  18. Suppression of two-photon resonantly enhanced nonlinear processes in extended media

    International Nuclear Information System (INIS)

    Garrett, W.R.; Moore, M.A.; Payne, M.G.; Wunderlich, R.K.

    1988-11-01

    On the basis of combined experimental and theoretical studies of nonlinear processes associated with two-photon excitations near 3d and 4d states in Na, we show how resonantly enhanced stimulated hyper-Raman emission, parametric four-wave mixing processes and total resonant two-photon absorption can become severely suppressed through the actions of internally generated fields on the total atomic response in extended media. 7 refs., 3 figs

  19. Nonlinear Elliptic Boundary Value Problems at Resonance with Nonlinear Wentzell Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Ciprian G. Gal

    2017-01-01

    Full Text Available Given a bounded domain Ω⊂RN with a Lipschitz boundary ∂Ω and p,q∈(1,+∞, we consider the quasilinear elliptic equation -Δpu+α1u=f in Ω complemented with the generalized Wentzell-Robin type boundary conditions of the form bx∇up-2∂nu-ρbxΔq,Γu+α2u=g on ∂Ω. In the first part of the article, we give necessary and sufficient conditions in terms of the given functions f, g and the nonlinearities α1, α2, for the solvability of the above nonlinear elliptic boundary value problems with the nonlinear boundary conditions. In other words, we establish a sort of “nonlinear Fredholm alternative” for our problem which extends the corresponding Landesman and Lazer result for elliptic problems with linear homogeneous boundary conditions. In the second part, we give some additional results on existence and uniqueness and we study the regularity of the weak solutions for these classes of nonlinear problems. More precisely, we show some global a priori estimates for these weak solutions in an L∞-setting.

  20. Linear and nonlinear resonance features of an erbium-doped fibre ...

    Indian Academy of Sciences (India)

    2014-07-01

    Jul 1, 2014 ... Abstract. The continuous-wave output of a single-mode erbium-doped fibre ring laser when sub- jected 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 ...

  1. The mixed BVP for second order nonlinear ordinary differential equation at resonance

    Czech Academy of Sciences Publication Activity Database

    Mukhigulashvili, Sulkhan

    2017-01-01

    Roč. 290, 2-3 (2017), s. 393-400 ISSN 0025-584X Institutional support: RVO:67985840 Keywords : mixed problem at resonance * nonlinear ordinary differencial equation Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 0.742, year: 2016

  2. Efficient analysis for nonlinear microwave characteristics of high-power HTS thin film microstrip resonators

    International Nuclear Information System (INIS)

    Kedar, Ashutosh; Kataria, N D

    2005-01-01

    This paper investigates the nonlinear effects of high-T c superconducting (HTS) thin film in high-power applications. A nonlinear model for complex surface impedance has been proposed for the efficient analysis of the nonlinearity of HTS thin films. Further, using the developed model, analysis of HTS-MSR has been done using the spectral domain method (SDM). The SDM formulation has been modified to account for finite conductivity and thickness of HTS films by incorporating a complex resistive boundary condition. The results have been validated with the experiments performed with microstrip resonators (MSRs) based on YBa 2 Cu 3 O 7-x (YBCO) thin films made by a laser ablation technique on LaAlO 3 substrates, characterized for their characteristics, namely, resonant frequency and quality factor measured as a function of temperature and input RF power. A close agreement between the theoretical and measured results has been achieved validating the analysis

  3. Excitation power quantities in phase resonance testing of nonlinear systems with phase-locked-loop excitation

    Science.gov (United States)

    Peter, Simon; Leine, Remco I.

    2017-11-01

    Phase resonance testing is one method for the experimental extraction of nonlinear normal modes. This paper proposes a novel method for nonlinear phase resonance testing. Firstly, the issue of appropriate excitation is approached on the basis of excitation power considerations. Therefore, power quantities known from nonlinear systems theory in electrical engineering are transferred to nonlinear structural dynamics applications. A new power-based nonlinear mode indicator function is derived, which is generally applicable, reliable and easy to implement in experiments. Secondly, the tuning of the excitation phase is automated by the use of a Phase-Locked-Loop controller. This method provides a very user-friendly and fast way for obtaining the backbone curve. Furthermore, the method allows to exploit specific advantages of phase control such as the robustness for lightly damped systems and the stabilization of unstable branches of the frequency response. The reduced tuning time for the excitation makes the commonly used free-decay measurements for the extraction of backbone curves unnecessary. Instead, steady-state measurements for every point of the curve are obtained. In conjunction with the new mode indicator function, the correlation of every measured point with the associated nonlinear normal mode of the underlying conservative system can be evaluated. Moreover, it is shown that the analysis of the excitation power helps to locate sources of inaccuracies in the force appropriation process. The method is illustrated by a numerical example and its functionality in experiments is demonstrated on a benchmark beam structure.

  4. 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.

  5. 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

    2015-03-12

    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.

  6. Log canonical thresholds of smooth Fano threefolds

    International Nuclear Information System (INIS)

    Cheltsov, Ivan A; Shramov, Konstantin A

    2008-01-01

    The complex singularity exponent is a local invariant of a holomorphic function determined by the integrability of fractional powers of the function. The log canonical thresholds of effective Q-divisors on normal algebraic varieties are algebraic counterparts of complex singularity exponents. For a Fano variety, these invariants have global analogues. In the former case, it is the so-called α-invariant of Tian; in the latter case, it is the global log canonical threshold of the Fano variety, which is the infimum of log canonical thresholds of all effective Q-divisors numerically equivalent to the anticanonical divisor. An appendix to this paper contains a proof that the global log canonical threshold of a smooth Fano variety coincides with its α-invariant of Tian. The purpose of the paper is to compute the global log canonical thresholds of smooth Fano threefolds (altogether, there are 105 deformation families of such threefolds). The global log canonical thresholds are computed for every smooth threefold in 64 deformation families, and the global log canonical thresholds are computed for a general threefold in 20 deformation families. Some bounds for the global log canonical thresholds are computed for 14 deformation families. Appendix A is due to J.-P. Demailly.

  7. Birationally rigid varieties. I. Fano varieties

    International Nuclear Information System (INIS)

    Pukhlikov, A V

    2007-01-01

    The theory of birational rigidity of rationally connected varieties generalises the classical rationality problem. This paper gives a survey of the current state of this theory and traces its history from Noether's theorem and the Lueroth problem to the latest results on the birational superrigidity of higher-dimensional Fano varieties. The main components of the method of maximal singularities are considered.

  8. Fano Factor in Strained Graphene Nanoribbon Nanodevices

    Institute of Scientific and Technical Information of China (English)

    Walid Soliman; Mina D.Asham; Adel H.Phillips

    2017-01-01

    We investigate the Fano factor in a strained armchair and zigzag graphene nanoribbon nanodevice under the effect of ac field in a wide range of frequencies at different temperatures (10 K T0 K).This nanodevice is modeled as follows:a graphene nanoribbon is connected to two metallic leads.These two metallic leads operate as a source and a drain.The conducting substance is the gate electrode in this three-terminal nanodevice.Another metallic gate is used to govern the electrostatics and the switching of the graphene nanoribbon channel The substances at the graphene nanoribbon/metal contact are controlled by the back gate.The photon-assisted tunneling probability is deduced by solving the Dirac eigenvalue differential equation in which the Fano factor is expressed in terms of this tunneling probability.The results show that for the investigated nanodevice,the Fano factor decreases as the frequency of the induced ac field increases,while it increases as the temperature increases.In general,the Fano factors for both strained armchair and zigzag graphene nanoribbons are different.This is due to the effect of the uniaxial strain.It is shown that the band structure parameters of graphene nanoribbons at the energy gap,the C-C bond length,the hopping integral,the Fermi energy and the width are modulated by uniaxial strain.This research gives us a promise of the present nanodevice being used for digital nanoelectronics and sensors.

  9. Progresses in the studies of adiabatic splitting of charged particle beams by crossing nonlinear resonances

    Directory of Open Access Journals (Sweden)

    A. Franchi

    2009-01-01

    Full Text Available The multiturn extraction from a circular particle accelerator is performed by trapping the beam inside stable islands of the horizontal phase space. In general, by crossing a resonance of order n, n+1 beamlets are created whenever the resonance is stable, whereas if the resonance is unstable the beam is split in n parts. Islands are generated by nonlinear magnetic fields, whereas the trapping is realized by means of a given tune variation so to cross adiabatically a resonance. Experiments at the CERN Proton Synchrotron carried out in 2007 gave the evidence of protons trapped in stable islands while crossing the one-third and one-fifth resonances. Dedicated experiments were also carried out to study the trapping process and its reversibility properties. The results of these measurement campaigns are presented and discussed in this paper.

  10. Progresses in the Studies of Adiabatic Splitting of Charged Particles Beams by Crossing Nonlinear Resonances

    CERN Document Server

    Franchi, A; Giovannozzi, M; CERN. Geneva. BE Department

    2009-01-01

    The multi-turn extraction from a circular particle accelerator is performed by trapping the beam inside stable islands of the horizontal phase space. In general, by crossing a resonance of order n, n+1 beamlets are created whenever the resonance is stable, whereas if the resonance is unstable the beam is split in n parts. Islands are generated by non-linear magnetic fields, whereas the trapping is realized by means of a given tune variation so to cross adiabatically a resonance. Experiments at the CERN Proton Synchrotron carried out in 2007 gave the evidence of protons trapped in stable islands while crossing the one-third and one-fifth resonances. Dedicated experiments were also carried out to study the trapping process and its reversibility properties. The results of these measurement campaigns are presented and discussed in this paper.

  11. Nonlinear Parameter Identification of a Resonant Electrostatic MEMS Actuator

    Science.gov (United States)

    Al-Ghamdi, Majed S.; Alneamy, Ayman M.; Park, Sangtak; Li, Beichen; Khater, Mahmoud E.; Abdel-Rahman, Eihab M.; Heppler, Glenn R.; Yavuz, Mustafa

    2017-01-01

    We experimentally investigate the primary superharmonic of order two and subharmonic of order one-half resonances of an electrostatic MEMS actuator under direct excitation. We identify the parameters of a one degree of freedom (1-DOF) generalized Duffing oscillator model representing it. The experiments were conducted in soft vacuum to reduce squeeze-film damping, and the actuator response was measured optically using a laser vibrometer. The predictions of the identified model were found to be in close agreement with the experimental results. We also identified the noise spectral density of process (actuation voltage) and measurement noise. PMID:28505097

  12. Nonlinear interactions of focused resonance cone fields with plasmas

    International Nuclear Information System (INIS)

    Stenzel, R.L.; Gekelman, W.

    1977-01-01

    A simple yet novel rf exciter structure has been developed for generating remotely intense rf fields in a magnetoplasma. It is a circular line source of radius R in a plane perpendicularB 0 driven with an rf signal at ω 0 E/sub rf/ 2 /nkT/sub e/>0.2, a strong density depression in the focal region (deltan/n>40%) is observed. The density perturbation modifies the cone angle and field distribution. This nonlinear interaction leads to a rapid growth of ion acoustic wave turbulence and a corresponding random rf field distribution in a broadened focal region. The development of the interaction is mapped in space and time

  13. Basic mode of nonlinear spin-wave resonance in normally magnetized ferrite films

    International Nuclear Information System (INIS)

    Gulyaev, Yu.V.; Zil'berman, P.E.; Timiryazev, A.G.; Tikhomirova, M.P.

    2000-01-01

    Modes of nonlinear and spin-wave resonance (SWR) in the normally magnetized ferrite films were studied both theoretically and experimentally. The particular emphasis was placed on the basic mode of SWR. One showed theoretically that with the growth of the precession amplitude the profile of the basic mode changed. The nonlinear shift of the resonance field depends on the parameters of fixing of the surface spins. Films of ferroyttrium garnet (FYG) with strong gradient of the single-axis anisotropy field along the film thickness, as well as, FYG films of the submicron thickness where investigated experimentally. With the intensification of Uhf-power one observed the sublinear shift of the basic mode resonance field following by the superlinear growth of the absorbed power. That kind of behaviour is explained by variation of the profile of the varying magnetization space distribution [ru

  14. Mechanical nonlinearity elimination with a micromechanical clamped-free semicircular beams resonator

    Science.gov (United States)

    Chen, Dongyang; Chen, Xuying; Wang, Yong; Liu, Xinxin; Guan, Yangyang; Xie, Jin

    2018-04-01

    This paper reports a micro-machined clamped-free semicircular beam resonator aiming to eliminate the nonlinearity that widely exists in traditional mechanical resonators. Cubic coefficients over vibration displacement due to axial extension of the beams are analyzed through theoretical modelling, and the corresponding frequency effect is demonstrated. With the device working in the elastic vibration mode, the cubic coefficients are eliminated by using a free end to release the nonlinear extension of beams and thus the inside axial stress. The amplitude-frequency (A-f) effect is overcome in a large region of source power, and the coefficient of frequency softening is linearized in a large region of polarization voltage. As a result, the resonator can be driven at larger vibration amplitude to achieve a high signal to noise ratio and power handling performance.

  15. Alfven wave resonances and flow induced by nonlinear Alfven waves in a stratified atmosphere

    International Nuclear Information System (INIS)

    Stark, B. A.; Musielak, Z. E.; Suess, S. T.

    1996-01-01

    A nonlinear, time-dependent, ideal MHD code has been developed and used to compute the flow induced by nonlinear Alfven waves propagating in an isothermal, stratified, plane-parallel atmosphere. The code is based on characteristic equations solved in a Lagrangian frame. Results show that resonance behavior of Alfven waves exists in the presence of a continuous density gradient and that the waves with periods corresponding to resonant peaks exert considerably more force on the medium than off-resonance periods. If only off-peak periods are considered, the relationship between the wave period and induced longitudinal velocity shows that short period WKB waves push more on the background medium than longer period, non-WKB, waves. The results also show the development of the longitudinal waves induced by finite amplitude Alfven waves. Wave energy transferred to the longitudinal mode may provide a source of localized heating

  16. Spatiotemporal behavior and nonlinear dynamics in a phase conjugate resonator

    Science.gov (United States)

    Liu, Siuying Raymond

    1993-01-01

    The work described can be divided into two parts. The first part is an investigation of the transient behavior and stability property of a phase conjugate resonator (PCR) below threshold. The second part is an experimental and theoretical study of the PCR's spatiotemporal dynamics above threshold. The time-dependent coupled wave equations for four-wave mixing (FWM) in a photorefractive crystal, with two distinct interaction regions caused by feedback from an ordinary mirror, was used to model the transient dynamics of a PCR below threshold. The conditions for self-oscillation were determined and the solutions were used to define the PCR's transfer function and analyze its stability. Experimental results for the buildup and decay times confirmed qualitatively the predicted behavior. Experiments were carried out above threshold to study the spatiotemporal dynamics of the PCR as a function of Pragg detuning and the resonator's Fresnel number. The existence of optical vortices in the wavefront were identified by optical interferometry. It was possible to describe the transverse dynamics and the spatiotemporal instabilities by modeling the three-dimensional-coupled wave equations in photorefractive FWM using a truncated modal expansion approach.

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

    KAUST Repository

    Hajjaj, Amal Z.; Hafiz, Md Abdullah Al; Younis, Mohammad I.

    2017-01-01

    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

  18. Control of the symmetry breaking in double-well potentials by the resonant nonlinearity management

    International Nuclear Information System (INIS)

    Nistazakis, H. E.; Frantzeskakis, D. J.; Malomed, B. A.; Kevrekidis, P. G.

    2011-01-01

    We introduce a one-dimensional model of Bose-Einstein condensates (BECs), combining the double-well potential, which is a usual setting for the onset of spontaneous-symmetry-breaking (SSB) effects, and time-periodic modulation of the nonlinearity, which may be implemented by means of the Feshbach-resonance-management (FRM) technique. Both cases of the nonlinearity that is repulsive or attractive on the average are considered. In the former case, the main effect produced by the application of the FRM is spontaneous self-trapping of the condensate in either of the two potential wells in parameter regimes where it would remain untrapped in the absence of the management. In the weakly nonlinear regime, the frequency of intrinsic oscillations in the FRM-induced trapped state is very close to half the FRM frequency, suggesting that the effect is accounted for by a parametric resonance. In the case of the attractive nonlinearity, the FRM-induced effect is the opposite, i.e., enforced detrapping of a state which is self-trapped in its unmanaged form. In the latter case, the frequency of oscillations of the untrapped mode is close to a quarter of the driving frequency, suggesting that a higher-order parametric resonance may account for this effect.

  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. 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.

  1. Nonlinearity of the refractive index due to an excitonic molecule resonance state in CdS

    International Nuclear Information System (INIS)

    Baumert, R.; Broser, I.; Buschick, K.

    1986-01-01

    The authors report the observation of an intensity-dependent refractive-index nonlinearity in CdS due to a resonance state where an excitonic molecule is created by induced absorption of light. The refractive index n as a function of the incident laser photon energy E is measured directly by light refraction in thin crystal prisms. A renormalized dielectric function describes the measured n(E) spectra well. This strong refractive-index nonlinearity is well suited to produce an optical bistability and to further strengthen the evidence of CdS to be an important material for laser-induced dynamic gratings

  2. Unexpected nonlinear effects and critical coupling in NbN superconducting microwave resonators

    International Nuclear Information System (INIS)

    Abdo, B.; Buks, E.

    2004-01-01

    Full Text:In this work, we have designed and fabricated several NbN superconducting stripline microwave resonators sputtered on sapphire substrates. The low temperature response exhibits strong and unexpected nonlinear effects, including sharp jumps as the frequency or poser are varied, frequency hysteresis loops changing direction as the input power is varied, and others. Contrary to some other superconducting resonators, a simple model of a one-dimensional Duffing resonator cannot account for the experimental results. Whereas the physical origin of the unusual nonlinear response of our samples remains an open question, our intensive experimental study of these effects under varying conditions provides some important insight. We consider a hypothesis according to which Josephson junctions forming weak links between the grains of the NbN are responsible for the observed behavior. We show that most of the experimental results are qualitatively consistent with such hypothesis. While revealing the underlying physics remains an outstanding challenge for future research, the utilization of the unusual nonlinear response for some novel applications is already demonstrated in the present work. In particular an operate the resonator as an inter modulation amplifier and find that the gain can be as high as 15 dB. To the best of our knowledge, inter modulation gain greater than unity has not been reported before in the scientific literature. In another application we demonstrate for the first time that the coupling between the resonator and its feed line can be made amplitude dependent. This novel mechanism allows us to tune the resonator into critical coupling conditions

  3. 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.

  4. Nonlinear properties of double and triple barrier resonant tunneling structures in the sub-THz range

    International Nuclear Information System (INIS)

    Karuzskij, A.L.; Perestoronin, A.V.; Volchkov, N.A.

    2012-01-01

    The high-frequency nonlinear properties of GaAs/AlAs resonant tunneling diode (RTD) nanostructures and perspectives of implementation of the quantum regime of amplification in such structures, which is especially efficient in the range of sub-THz and THz ranges, are investigated. It is shown that in a triple barrier RTD the symmetry between the processes of amplification and dissipation can be avoided because of the interaction of an electromagnetic wave with both of resonant states in two quantum wells, that results in the significant growth of an RTD efficiency [ru

  5. 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

  6. Frequency tuning, nonlinearities and mode coupling in circular mechanical graphene resonators

    International Nuclear Information System (INIS)

    Eriksson, A M; Midtvedt, D; Croy, A; Isacsson, A

    2013-01-01

    We study circular nanomechanical graphene resonators by means of continuum elasticity theory, treating them as membranes. We derive dynamic equations for the flexural mode amplitudes. Due to the geometrical nonlinearity the mode dynamics can be modeled by coupled Duffing equations. By solving the Airy stress problem we obtain analytic expressions for the eigenfrequencies and nonlinear coefficients as functions of the radius, suspension height, initial tension, back-gate voltage and elastic constants, which we compare with finite element simulations. Using perturbation theory, we show that it is necessary to include the effects of the non-uniform stress distribution for finite deflections. This correctly reproduces the spectrum and frequency tuning of the resonator, including frequency crossings. (paper)

  7. Design and implementation of optical switches based on nonlinear plasmonic ring resonators: Circular, square and octagon

    Science.gov (United States)

    Ghadrdan, Majid; Mansouri-Birjandi, Mohammad Ali

    2018-05-01

    In this paper, all-optical plasmonic switches (AOPS) based on various configurations of circular, square and octagon nonlinear plasmonic ring resonators (NPRR) were proposed and numerically investigated. Each of these configurations consisted of two metal-insulator-metal (MIM) waveguides coupled to each other by a ring resonator (RR). Nonlinear Kerr effect was used to show switching performance of the proposed NPRR. The result showed that the octagon switch structure had lower threshold power and higher transmission ratio than square and circular switch structures. The octagon switch structure had a low threshold power equal to 7.77 MW/cm2 and the high transmission ratio of approximately 0.6. Therefore, the octagon switch structure was an appropriate candidate to be applied in optical integration circuits as an AOPS.

  8. Phase locking and quantum statistics in a parametrically driven nonlinear resonator

    OpenAIRE

    Hovsepyan, G. H.; Shahinyan, A. R.; Chew, Lock Yue; Kryuchkyan, G. Yu.

    2016-01-01

    We discuss phase-locking phenomena at low-level of quanta for parametrically driven nonlinear Kerr resonator (PDNR) in strong quantum regime. 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 Wigner functions of cavity mode showing two-fold symmetry in phase space and analyse formation of phase-locked states in the regular as well as the quantum chaotic regime.

  9. 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.

  10. 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.

  11. Delay-controlled primary and stochastic resonances of the SD oscillator with stiffness nonlinearities

    Science.gov (United States)

    Yang, Tao; Cao, Qingjie

    2018-03-01

    This work presents analytical studies of the stiffness nonlinearities SD (smooth and discontinuous) oscillator under displacement and velocity feedback control with a time delay. The SD oscillator can capture the qualitative characteristics of quasi-zero-stiffness and negative-stiffness. We focus mainly on the primary resonance of the quasi-zero-stiffness SD oscillator and the stochastic resonance (SR) of the negative-stiffness SD oscillator. Using the averaging method, we have been analyzed the amplitude response of the quasi-zero-stiffness SD oscillator. In this regard, the optimum time delay for changing the control intensity according to the optimization standard proposed can be obtained. For the optimum time delay, increasing the displacement feedback intensity is advantageous to suppress the vibrations in resonant regime where vibration isolation is needed, however, increasing the velocity feedback intensity is advantageous to strengthen the vibrations. Moreover, the effects of time-delayed feedback on the SR of the negative-stiffness SD oscillator are investigated under harmonic forcing and Gaussian white noise, based on the Langevin and Fokker-Planck approaches. The time-delayed feedback can enhance the SR phenomenon where vibrational energy harvesting is needed. This paper established the relationship between the parameters and vibration properties of a stiffness nonlinearities SD which provides the guidance for optimizing time-delayed control for vibration isolation and vibrational energy harvesting of the nonlinear systems.

  12. Coexistence of Multiple Nonlinear States in a Tristable Passive Kerr Resonator

    Directory of Open Access Journals (Sweden)

    Miles Anderson

    2017-08-01

    Full Text Available Passive Kerr cavities driven by coherent laser fields display a rich landscape of nonlinear physics, including bistability, pattern formation, and localized dissipative structures (solitons. Their conceptual simplicity has for several decades offered an unprecedented window into nonlinear cavity dynamics, providing insights into numerous systems and applications ranging from all-optical memory devices to microresonator frequency combs. Yet despite the decades of study, a recent theoretical work has surprisingly alluded to an entirely new and unexplored paradigm in the regime where nonlinearly tilted cavity resonances overlap with one another [T. Hansson and S. Wabnitz, J. Opt. Soc. Am. B 32, 1259 (2015JOBPDE0740-322410.1364/JOSAB.32.001259]. We use synchronously driven fiber ring resonators to experimentally access this regime and observe the rise of new nonlinear dissipative states. Specifically, we observe, for the first time to the best of our knowledge, the stable coexistence of temporal Kerr cavity solitons and extended modulation instability (Turing patterns, and perform real-time measurements that unveil the dynamics of the ensuing nonlinear structure. When operating in the regime of continuous wave tristability, we further observe the coexistence of two distinct cavity soliton states, one of which can be identified as a “super” cavity soliton, as predicted by Hansson and Wabnitz. Our experimental findings are in excellent agreement with theoretical analyses and numerical simulations of the infinite-dimensional Ikeda map that governs the cavity dynamics. The results from our work reveal that experimental systems can support complex combinations of distinct nonlinear states, and they could have practical implications to future microresonator-based frequency comb sources.

  13. Coexistence of Multiple Nonlinear States in a Tristable Passive Kerr Resonator

    Science.gov (United States)

    Anderson, Miles; Wang, Yadong; Leo, François; Coen, Stéphane; Erkintalo, Miro; Murdoch, Stuart G.

    2017-07-01

    Passive Kerr cavities driven by coherent laser fields display a rich landscape of nonlinear physics, including bistability, pattern formation, and localized dissipative structures (solitons). Their conceptual simplicity has for several decades offered an unprecedented window into nonlinear cavity dynamics, providing insights into numerous systems and applications ranging from all-optical memory devices to microresonator frequency combs. Yet despite the decades of study, a recent theoretical work has surprisingly alluded to an entirely new and unexplored paradigm in the regime where nonlinearly tilted cavity resonances overlap with one another [T. Hansson and S. Wabnitz, J. Opt. Soc. Am. B 32, 1259 (2015), 10.1364/JOSAB.32.001259]. We use synchronously driven fiber ring resonators to experimentally access this regime and observe the rise of new nonlinear dissipative states. Specifically, we observe, for the first time to the best of our knowledge, the stable coexistence of temporal Kerr cavity solitons and extended modulation instability (Turing) patterns, and perform real-time measurements that unveil the dynamics of the ensuing nonlinear structure. When operating in the regime of continuous wave tristability, we further observe the coexistence of two distinct cavity soliton states, one of which can be identified as a "super" cavity soliton, as predicted by Hansson and Wabnitz. Our experimental findings are in excellent agreement with theoretical analyses and numerical simulations of the infinite-dimensional Ikeda map that governs the cavity dynamics. The results from our work reveal that experimental systems can support complex combinations of distinct nonlinear states, and they could have practical implications to future microresonator-based frequency comb sources.

  14. Determination of Fano's factor in semiconductors

    International Nuclear Information System (INIS)

    Gomes, P.R.S.

    1975-07-01

    A study was made of three different semiconductor detectors: intrinsic germanium, germanium drifted with lithium, and silicon drifted with lithium. In the efficiency measurements for these detectors, special attention was paid to the escape of the germanium X-rays produced within the detector. The principal part of this work is the determination of the Fano factor for germanium and silicon. A great deal of attention was given to the analysis of experimental results. Different criteria for eliminating the linewidth contribution due to charge collection fluctuations lead to widely different values and have caused great controversy over the value of the Fano factor. Measurements were made for the three detectors using energies of 14.4 kev, 35.4 kev, 46.5 kev, 59.5 kev, 81 kev, 88 kev, 122 kev and 136.5 kev and the results indicate a Fano factor of 0.105 +- 0.004 for germanium and 0.130 +- 0.120 for silicon. (author) [pt

  15. Embedding and partial resolution of complex cones over Fano threefolds

    Energy Technology Data Exchange (ETDEWEB)

    Dwivedi, Siddharth, E-mail: sdwivedi@iitk.ac.in

    2016-12-15

    This work deals with the study of embeddings of toric Calabi–Yau fourfolds which are complex cones over the smooth Fano threefolds. In particular, we focus on finding various embeddings of Fano threefolds inside other Fano threefolds and study the partial resolution of the latter in hope to find new toric dualities. We find many diagrams possible for many of these Fano threefolds, but unfortunately, none of them are consistent quiver theories. We also obtain a quiver Chern–Simons theory which matches a theory known to the literature, thus providing an alternate method of obtaining it.

  16. Optimal trajectory control of a series-resonant inverter with a non-linear resonant inductor

    NARCIS (Netherlands)

    Huisman, H.; Baskurt, F.; Bouloukos, A; Baars, N.H.; Lomonova, E.A.

    2017-01-01

    ies-Resonant (SR) converters have been used as building blocks for DC-AC and DC-DC power converters for at least half a century. Applications were first found in induction heating [1], where generating a substantial AC current at moderately high frequency was required by the application. Later, the

  17. The Scientific Legacy of Ugo Fano

    Science.gov (United States)

    Inokuti, Mitio

    2001-04-01

    In 1934 Fano received a Sc. D. degree in mathematics at University of Turin, Italy (the city of his birth in 1912). He was then led to physics by his cousin Guilio Racah, and received postdoctoral training from Fermi at Rome and from Heisenberg at Leipzig. He worked at institutions near Washington, D. C. during the war, and joined the staff of the National Bureau of Standards in 1946. He became a professor of physics at The University of Chicago in 1966. His contributions to radiation physics, atomic and molecular physics, and statistical physics are extensive and outstanding. Recognition includes many honors such as the Fermi Award by the DOE, and terms such as the Beutler-Fano profile of certain spectral lines, the Fano factor characterizing the fluctuations of the radiation-induced ionization, the Fano-Lichten mechanism for inelastic atomic collisions, and the Fano effect leading to spin-polarized photoelectrons. His work follows a style inherited from Fermi and is characterized by incisive insight into the physics behind experimental data, penetrating mathematical analysis, and close communications with many colleagues. Because he took a leading role in developing new areas of research and in nurturing young scientists, his influence now permeates many topics of physics. They include far uv and soft x-ray spectroscopy with synchrotron radiation and fundamental radiological physics, both stemming from his time at NBS, as well as multi-channel quantum-defect theory and hyperspherical-coordinate approach, both pioneered at Chicago. Fuller accounts of his life and science are seen in Inokuti [1], in Rau [2], and in a forthcoming special issue of Physics Essays in his honor. The present work is supported by U. S. DOE, Office of Science, Nuclear Physics Division, under Contract No. W-31-109-Eng-38. References 1. M. Inokuti, in Fundamental Processes of Atomic Dynamics, J. S. Briggs et al. (eds.), (Plenum, New York, 1988), p. 1. 2. A. R. P. Rau, Comments At. Mol. Phys

  18. The scientific legacy of Ugo Fano

    International Nuclear Information System (INIS)

    Inokuti, M.

    2001-01-01

    In 1934 Fano received a Sc. D. degree in mathematics at University of Turin, Italy (the city of his birth in 1912). He was then led to physics by his cousin Guilio Racah, and received postdoctoral training from Fermi at Rome and from Heisenberg at Leipzig. He worked at institutions near Washington, D. C. during the war, and joined the staff of the National Bureau of Standards in 1946. He became a professor of physics at The University of Chicago in 1966. His contributions to radiation physics, atomic and molecular physics, and statistical physics are extensive and outstanding. Recognition includes many honors such as the Fermi Award by the DOE, and terms such as the Beutler-Fano profile of certain spectral lines, the Fano factor characterizing the fluctuations of the radiation-induced ionization, the Fano-Lichten mechanism for inelastic atomic collisions, and the Fano effect leading to spin-polarized photoelectrons. His work follows a style inherited from Fermi and is characterized by incisive insight into the physics behind experimental data, penetrating mathematical analysis, and close communications with many colleagues. Because he took a leading role in developing new areas of research and in nurturing young scientists, his influence now permeates many topics of physics. They include far uv and soft x-ray spectroscopy with synchrotron radiation and fundamental radiological physics, both stemming from his time at NBS, as well as multi-channel quantum-defect theory and hyperspherical-coordinate approach, both pioneered at Chicago. Fuller accounts of his life and science are seen in Inokuti [1], in Rau [2], and in a forthcoming special issue of Physics Essays in his honor. The present work is supported by U. S. DOE, Office of Science, Nuclear Physics Division, under Contract No. W-31-109-Eng-38. References 1. M. Inokuti, in Fundamental Processes of Atomic Dynamics, J. S. Briggs et al. (eds.), (Plenum, New York, 1988), p. 1. 2. A. R. P. Rau, Comments At. Mol. Phys

  19. 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.

  20. 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.

  1. 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.

  2. Fano lineshapes of 'Peak-tracking chip' spatial profiles analyzed with correlation analysis for bioarray imaging and refractive index sensing

    KAUST Repository

    Bougot-Robin, K.; Li, S.; Yue, W.; Chen, L. Q.; Zhang, Xixiang; Wen, W. J.; Benisty, H.

    2013-01-01

    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.

  3. Efficient analysis for nonlinear microwave characteristics of high-power HTS thin film microstrip resonators

    Energy Technology Data Exchange (ETDEWEB)

    Kedar, Ashutosh [RADL Division, Electronics and Radar Development Establishment, C V Raman Nagar, Bangalore-560093 (India); Kataria, N D [National Physical Laboratory, New Delhi (India)

    2005-08-01

    This paper investigates the nonlinear effects of high-T{sub c} superconducting (HTS) thin film in high-power applications. A nonlinear model for complex surface impedance has been proposed for the efficient analysis of the nonlinearity of HTS thin films. Further, using the developed model, analysis of HTS-MSR has been done using the spectral domain method (SDM). The SDM formulation has been modified to account for finite conductivity and thickness of HTS films by incorporating a complex resistive boundary condition. The results have been validated with the experiments performed with microstrip resonators (MSRs) based on YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) thin films made by a laser ablation technique on LaAlO{sub 3} substrates, characterized for their characteristics, namely, resonant frequency and quality factor measured as a function of temperature and input RF power. A close agreement between the theoretical and measured results has been achieved validating the analysis.

  4. Controlled generation of nonlinear resonances through sinusoidal lattice modes in Bose–Einstein condensate

    International Nuclear Information System (INIS)

    Das, Priyam; Panigrahi, Prasanta K

    2015-01-01

    We study Bose–Einstein condensate in the combined presence of time modulated optical lattice and harmonic trap in the mean-field approach. Through the self-similar method, we show the existence of sinusoidal lattice modes in this inhomogeneous system, commensurate with the lattice potential. A significant advantage of this system is wide tunability of the parameters through chirp management. The combined effect of the interaction, harmonic trap and lattice potential leads to the generation of nonlinear resonances, exactly where the matter wave changes its direction. When the harmonic trap is switched off, the BEC undergoes a nonlinear compression for the static optical lattice potential. For better understanding of chirp management and the nature of the sinusoidal excitation, we investigate the energy spectrum of the condensate, which clearly reveals the generation of nonlinear resonances in the appropriate regime. We have also identified a classical dynamical phase transition occurring in the system, where loss of superfluidity takes the superfluid phase to an insulating state. (paper)

  5. 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

  6. Long-term evolution of electron distribution function due to nonlinear resonant interaction with whistler mode waves

    Science.gov (United States)

    Artemyev, Anton V.; Neishtadt, Anatoly I.; Vasiliev, Alexei A.

    2018-04-01

    Accurately modelling and forecasting of the dynamics of the Earth's radiation belts with the available computer resources represents an important challenge that still requires significant advances in the theoretical plasma physics field of wave-particle resonant interaction. Energetic electron acceleration or scattering into the Earth's atmosphere are essentially controlled by their resonances with electromagnetic whistler mode waves. The quasi-linear diffusion equation describes well this resonant interaction for low intensity waves. During the last decade, however, spacecraft observations in the radiation belts have revealed a large number of whistler mode waves with sufficiently high intensity to interact with electrons in the nonlinear regime. A kinetic equation including such nonlinear wave-particle interactions and describing the long-term evolution of the electron distribution is the focus of the present paper. Using the Hamiltonian theory of resonant phenomena, we describe individual electron resonance with an intense coherent whistler mode wave. The derived characteristics of such a resonance are incorporated into a generalized kinetic equation which includes non-local transport in energy space. This transport is produced by resonant electron trapping and nonlinear acceleration. We describe the methods allowing the construction of nonlinear resonant terms in the kinetic equation and discuss possible applications of this equation.

  7. Excitation of multiphase waves of the nonlinear Schroedinger equation by capture into resonances

    International Nuclear Information System (INIS)

    Friedland, L.; Shagalov, A.G.

    2005-01-01

    A method for adiabatic excitation and control of multiphase (N-band) waves of the periodic nonlinear Schroedinger (NLS) equation is developed. The approach is based on capturing the system into successive resonances with external, small amplitude plane waves having slowly varying frequencies. The excitation proceeds from zero and develops in stages, as an (N+1)-band (N=0,1,2,...), growing amplitude wave is formed in the (N+1)th stage from an N-band solution excited in the preceding stage. The method is illustrated in simulations, where the excited multiphase waves are analyzed via the spectral approach of the inverse scattering transform method. The theory of excitation of 0- and 1-band NLS solutions by capture into resonances is developed on the basis of a weakly nonlinear version of Whitham's averaged variational principle. The phenomenon of thresholds on the driving amplitudes for capture into successive resonances and the stability of driven, phase-locked solutions in these cases are discussed

  8. 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.

  9. Nonlinear Modeling and Simulation of Thermal Effects in Microcantilever Resonators Dynamic

    International Nuclear Information System (INIS)

    Tadayon, M A; Sayyaadi, H; Jazar, G Nakhaie

    2006-01-01

    Thermal dependency of material characteristics in micro electromechanical systems strongly affects their performance, design, and control. Hence, it is essential to understand and model that in MEMS devices to optimize their designs. A thermal phenomenon introduces two main effects: damping due to internal friction, and softening due to Young modulus temperature relation. Based on some reported theoretical and experimental results, we model the thermal phenomena and use two Lorentzian functions to describe the restoring and damping forces caused by thermal phenomena. In order to emphasize the thermal effects, a nonlinear model of the MEMS, by considering capacitor nonlinearity, have been used. The response of the system is developed by employing multiple time scales perturbation method on nondimensionalized form of equations. Frequency response, resonant frequency and peak amplitude are examined for variation of dynamic parameters involved

  10. Numerical analysis of non-linear vibrations of a fractionally damped cylindrical shell under the conditions of combinational internal resonance

    Directory of Open Access Journals (Sweden)

    Rossikhin Yury A.

    2018-01-01

    Full Text Available Non-linear damped vibrations of a cylindrical shell embedded into a fractional derivative medium are investigated for the case of the combinational internal resonance, resulting in modal interaction, using two different numerical methods with further comparison of the results obtained. The damping properties of the surrounding medium are described by the fractional derivative Kelvin-Voigt model utilizing the Riemann-Liouville fractional derivatives. Within the first method, the generalized displacements of a coupled set of nonlinear ordinary differential equations of the second order are estimated using numerical solution of nonlinear multi-term fractional differential equations by the procedure based on the reduction of the problem to a system of fractional differential equations. According to the second method, the amplitudes and phases of nonlinear vibrations are estimated from the governing nonlinear differential equations describing amplitude-and-phase modulations for the case of the combinational internal resonance. A good agreement in results is declared.

  11. Nonlinear resonance rotation of polarization plane in the conditions of coherent captivity of occupation

    International Nuclear Information System (INIS)

    Akhmedzhanov, R.A.; Zelenskij, I.V.

    2002-01-01

    The effect of the nonlinear resonance rotation of the polarization plane of the electromagnetic radiation under the conditions of the coherent occupation captivity in the 87 Rb pairs at the F = 2 → F' = 1 transition of the D 1 -line is studied within the wide range of the experimental parameters change. The nonmonotonous dependence of the turning angle on the laser radiation intensity and applied magnetic field is identified. The effect of the occupation optical pumping out on the F = 1 level is discussed. The twofold increase in the polarization plane turning angle by the pumping out compensation is experimentally demonstrated [ru

  12. Damping characteristic identification of non-linear soil-structural system interaction by phase resonance

    International Nuclear Information System (INIS)

    Poterasu, V.F.

    1984-01-01

    It is presented a method and the phase resonance for damping characteristic identification of non-linear soil-structural interaction. The algorithm can be applied in case of any, not necessarily, damping characteristic of the system examined. For the identification, the system is harmonically excited and are considered the super-harmonic amplitudes for odd and even powers of the x. The response of shear beam system for different levels of base excitation and for different locations of the load is considered. (Author) [pt

  13. Statistics of Poincare recurrences and the structure of the stochastic layer of a nonlinear resonance

    International Nuclear Information System (INIS)

    Chirikov, B.V.; Shepelyansky, D.L.

    1983-02-01

    Motion in the stochastic layer around the separatrix of a nonlinear resonance was investigated. The integral distribution function F(tau) of trajectory recurrence times tau to the center of the layer was numerically determined. It was found that the distribution F(tau) = A tau - /sup p/ is a power function, the exponent assuming two different values: for tau less than or equal to tau 0 , p = 1/2 and for tau >> tau 0 , p = 3/2 (time tau 0 is determined by the characteristics of the layer)

  14. Synthesis, multi-nonlinear dielectric resonance and electromagnetic absorption properties of hcp-cobalt particles

    International Nuclear Information System (INIS)

    Wen, Shulai; Liu, Ying; Zhao, Xiuchen; Cheng, Jingwei; Li, Hong

    2014-01-01

    Hcp-cobalt particles were successfully prepared by a liquid phase reduction method, and the microstructure, static magnetic properties, electromagnetic and microwave absorption properties of the cobalt particles with irregular shape were investigated in detail. The measured results indicate that the saturation magnetization was less than that of hcp-Co single crystals, and the coercivity was larger than that of bulk cobalt crystal. The permittivity presents multi-nonlinear dielectric resonance, which may result from the irregular shape containing parts of cutting angle of dodecahedron of cobalt particles. The real part of permeability decreases with the frequency, and the imaginary part has a wide resonant peak. The paraffin-based composite containing 70 wt% cobalt particles possessed strong absorption characteristics with a minimum RL of −38.97 dB at 10.81 GHz and an absorption band with RL under −10 dB from 8.72 to 13.26 GHz when the thickness is 1.8 mm, which exhibits excellent microwave absorption in middle and high frequency. The architectural design of material morphologies is important for improving microwave absorption properties toward future application. - Highlights: • Hcp-cobalt particles were prepared by a liquid phase reduction method. • The saturation magnetization was less than that of hcp-Co single crystals. • The permittivity presents multi-nonlinear dielectric resonance. • The real part of permeability decreases with frequency, and the imaginary part presents a wide resonant peak. • The paraffin-based composite possessed a minimum RL of −38.97 dB at 10.81 GHz

  15. High-sensitivity dc field magnetometer using nonlinear resonance magnetoelectric effect

    International Nuclear Information System (INIS)

    Burdin, D.A.; Chashin, D.V.; Ekonomov, N.A.; Fetisov, Y.K.; Stashkevich, A.A.

    2016-01-01

    The design and operation principle of dc field magnetometer using nonlinear resonance magnetoelectric effect in a ferromagnetic–piezoelectric structure are described. It is shown that under action of ac pumping magnetic field the structure generates the output voltage containing higher harmonics whose amplitudes depend on the dc magnetic field. Best performance of the device is obtained if the signal of the third harmonics is used for the dc field measurement. The sensitivity can be considerably (by approximately three orders of magnitude) increased if advantage is taken of the acoustic resonance of the structure at this frequency. There exists the optimal pumping field ensuring the highest sensitivity. Further increasing of this field expands the range of measurable dc fields at the expense of deteriorated sensitivity. The magnetometer fabricated on the basis of a planar langatate-Metglas structure had sensitivity up to ~1 V/Oe and allowed detection of the fields as low as ~10"−"5 Oe. - Highlights: • Operational principle and design of new type dc field magnetometer is described. • Magnetometer uses nonlinear magnetoelectric effect in a langatate-Metglas structure. • Magnetometer has sensitivity of ~1 V/Oe and detects fields as low as 10"−"5 Oe. • The proposed magnetometer can compete with well known fluxgate sensors.

  16. High-sensitivity dc field magnetometer using nonlinear resonance magnetoelectric effect

    Energy Technology Data Exchange (ETDEWEB)

    Burdin, D.A.; Chashin, D.V.; Ekonomov, N.A. [Moscow State University of Information Technologies, Radio Engineering and Electronics, Moscow (Russian Federation); Fetisov, Y.K., E-mail: fetisov@mirea.ru [Moscow State University of Information Technologies, Radio Engineering and Electronics, Moscow (Russian Federation); Stashkevich, A.A. [LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 93430 Villetaneuse (France)

    2016-05-01

    The design and operation principle of dc field magnetometer using nonlinear resonance magnetoelectric effect in a ferromagnetic–piezoelectric structure are described. It is shown that under action of ac pumping magnetic field the structure generates the output voltage containing higher harmonics whose amplitudes depend on the dc magnetic field. Best performance of the device is obtained if the signal of the third harmonics is used for the dc field measurement. The sensitivity can be considerably (by approximately three orders of magnitude) increased if advantage is taken of the acoustic resonance of the structure at this frequency. There exists the optimal pumping field ensuring the highest sensitivity. Further increasing of this field expands the range of measurable dc fields at the expense of deteriorated sensitivity. The magnetometer fabricated on the basis of a planar langatate-Metglas structure had sensitivity up to ~1 V/Oe and allowed detection of the fields as low as ~10{sup −5} Oe. - Highlights: • Operational principle and design of new type dc field magnetometer is described. • Magnetometer uses nonlinear magnetoelectric effect in a langatate-Metglas structure. • Magnetometer has sensitivity of ~1 V/Oe and detects fields as low as 10{sup −5} Oe. • The proposed magnetometer can compete with well known fluxgate sensors.

  17. 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.

  18. 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.

  19. On the Nonlinear Dynamics of a Doubly Clamped Microbeam near Primary Resonance

    KAUST Repository

    Jaber, Nizar; Masri, Karim M.; Younis, Mohammad I.

    2017-01-01

    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.

  20. Optimum Design of a Nonlinear Vibration Absorber Coupled to a Resonant Oscillator: A Case Study

    Directory of Open Access Journals (Sweden)

    H. F. Abundis-Fong

    2018-01-01

    Full Text Available This paper presents the optimal design of a passive autoparametric cantilever beam vibration absorber for a linear mass-spring-damper system subject to harmonic external force. The design of the autoparametric vibration absorber is obtained by using an approximation of the nonlinear frequency response function, computed via the multiple scales method. Based on the solution given by the perturbation method mentioned above, a static optimization problem is formulated in order to determine the optimum parameters (mass and length of the nonlinear absorber which minimizes the steady state amplitude of the primary mass under resonant conditions; then, a PZT actuator is cemented to the base of the beam, so the nonlinear absorber is made active, thus enabling the possibility of controlling the effective stiffness associated with the passive absorber and, as a consequence, the implementation of an active vibration control scheme able to preserve, as possible, the autoparametric interaction as well as to compensate varying excitation frequencies and parametric uncertainty. Finally, some simulations and experimental results are included to validate and illustrate the dynamic performance of the overall system.

  1. On the Nonlinear Dynamics of a Doubly Clamped Microbeam near Primary Resonance

    KAUST Repository

    Jaber, Nizar

    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.

  2. Novel threshold pressure sensors based on nonlinear dynamics of MEMS resonators

    Science.gov (United States)

    Hasan, Mohammad H.; Alsaleem, Fadi M.; Ouakad, Hassen M.

    2018-06-01

    Triggering an alarm in a car for low air-pressure in the tire or tripping an HVAC compressor if the refrigerant pressure is lower than a threshold value are examples for applications where measuring the amount of pressure is not as important as determining if the pressure has exceeded a threshold value for an action to occur. Unfortunately, current technology still relies on analog pressure sensors to perform this functionality by adding a complex interface (extra circuitry, controllers, and/or decision units). In this paper, we demonstrate two new smart tunable-threshold pressure switch concepts that can reduce the complexity of a threshold pressure sensor. The first concept is based on the nonlinear subharmonic resonance of a straight double cantilever microbeam with a proof mass and the other concept is based on the snap-through bi-stability of a clamped-clamped MEMS shallow arch. In both designs, the sensor operation concept is simple. Any actuation performed at a certain pressure lower than a threshold value will activate a nonlinear dynamic behavior (subharmonic resonance or snap-through bi-stability) yielding a large output that would be interpreted as a logic value of ONE, or ON. Once the pressure exceeds the threshold value, the nonlinear response ceases to exist, yielding a small output that would be interpreted as a logic value of ZERO, or OFF. A lumped, single degree of freedom model for the double cantilever beam, that is validated using experimental data, and a continuous beam model for the arch beam, are used to simulate the operation range of the proposed sensors by identifying the relationship between the excitation signal and the critical cut-off pressure.

  3. Theory of Self-pulsing in Photonic Crystal Fano Lasers

    DEFF Research Database (Denmark)

    Rasmussen, Thorsten Svend; Yu, Yi; Mørk, Jesper

    2017-01-01

    -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......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...

  4. Nonlinear Right-Hand Polarized Wave in Plasma in the Electron Cyclotron Resonance Region

    Science.gov (United States)

    Krasovitskiy, V. B.; Turikov, V. A.

    2018-05-01

    The propagation of a nonlinear right-hand polarized wave along an external magnetic field in subcritical plasma in the electron cyclotron resonance region is studied using numerical simulations. It is shown that a small-amplitude plasma wave excited in low-density plasma is unstable against modulation instability with a modulation period equal to the wavelength of the excited wave. The modulation amplitude in this case increases with decreasing detuning from the resonance frequency. The simulations have shown that, for large-amplitude waves of the laser frequency range propagating in plasma in a superstrong magnetic field, the maximum amplitude of the excited longitudinal electric field increases with the increasing external magnetic field and can reach 30% of the initial amplitude of the electric field in the laser wave. In this case, the energy of plasma electrons begins to substantially increase already at magnetic fields significantly lower than the resonance value. The laser energy transferred to plasma electrons in a strong external magnetic field is found to increase severalfold compared to that in isotropic plasma. It is shown that this mechanism of laser radiation absorption depends only slightly on the electron temperature.

  5. Flexible photonic-crystal Fano filters based on transferred semiconductor nanomembranes

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Weidong; Yang Hongjun; Qiang Zexuan; Chen Li; Yang Weiquan; Chuwongin, Santhad; Zhao Deyin [Department of Electrical Engineering, NanoFAB Center, University of Texas at Arlington, TX 76019 (United States); Ma Zhenqiang; Qin Guoxuan; Pang Huiqing, E-mail: wzhou@uta.ed, E-mail: mazq@engr.wisc.ed [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, WI 53706 (United States)

    2009-12-07

    Crystalline semiconductor nanomembranes (NMs), which are transferable, stackable, bondable and manufacturable, offer unprecedented opportunities for unique and novel device applications. We report and review here nanophotonic devices based on stacked semiconductor NMs that were built on Si, glass and flexible PET substrates. Photonic-crystal Fano resonance based surface-normal optical filters and broadband reflectors have been demonstrated with unique angle and polarization properties. Such a low temperature NM stacking process can lead to a paradigm shift on silicon photonic integration and inorganic flexible photonics.

  6. Non-linear interactions of multi-level atoms with a near-resonant standing wave

    International Nuclear Information System (INIS)

    O'Kane, T.J.; Scholten, R.E.; Walkiewicz, M.R.; Farrell, P.M.

    1998-01-01

    Using a semiclassical density matrix formalism we have calculated the behavior of multi-level atoms interacting with a standing wave field, and show how complex non-linear phenomena, including multi-photon effects, combine to produce saturation spectra as observed in experiments. We consider both 20-level sodium and 24-level rubidium models, contrasting these with a simple 2-level case. The influence of parameters such as atomic trajectory and the time the atom remains in the beam are shown to have a critical effect on the lineshape of these resonances and the emission/absorption processes. Stable oscillations in the excited state populations for both the two-level and multi-level cases are shown to be limit cycles. These limit cycles undergo period doubling as the system evolves into chaos. Finally, using a Monte Carlo treatment, these processes average to produce saturated absorption spectra complete with power and Doppler broadening effects consistent with experiment. (authors)

  7. A T-shaped double quantum dot system as a Fano interferometer: Interplay of coherence and correlation upon spin currents

    Science.gov (United States)

    Fernandes, I. L.; Cabrera, G. G.

    2018-05-01

    Based on Keldysh non-equilibrium Green function method, we have investigated spin current production in a hybrid T-shaped device, consisting of a central quantum dot connected to the leads and a side dot which only couples to the central dot. The topology of this structure allows for quantum interference of the different paths that go across the device, yielding Fano resonances in the spin dependent transport properties. Correlation effects are taken into account at the central dot and handled within a mean field approximation. Its interplay with the Fano effect is analyzed in the strong coupling regime. Non-vanishing spin currents are only obtained when the leads are ferromagnetic, the current being strongly dependent on the relative orientation of the lead polarizations. We calculate the conductance (spin and charge) by numerically differentiating the current, and a rich structure is obtained as a manifestation of quantum coherence and correlation effects. Increase of the Coulomb interaction produces localization of states at the side dot, largely suppressing Fano resonances. The interaction is also responsible for the negative values of the spin conductance in some regions of the voltage near resonances, effect which is the spin analog of the Esaki tunnel diode. We also analyze control of the currents via gate voltages applied to the dots, possibility which is interesting for practical operations.

  8. Tuning the Fano factor of graphene via Fermi velocity modulation

    Science.gov (United States)

    Lima, Jonas R. F.; Barbosa, Anderson L. R.; Bezerra, C. G.; Pereira, Luiz Felipe C.

    2018-03-01

    In this work we investigate the influence of a Fermi velocity modulation on the Fano factor of periodic and quasi-periodic graphene superlattices. We consider the continuum model and use the transfer matrix method to solve the Dirac-like equation for graphene where the electrostatic potential, energy gap and Fermi velocity are piecewise constant functions of the position x. We found that in the presence of an energy gap, it is possible to tune the energy of the Fano factor peak and consequently the location of the Dirac point, by a modulation in the Fermi velocity. Hence, the peak of the Fano factor can be used experimentally to identify the Dirac point. We show that for higher values of the Fermi velocity the Fano factor goes below 1/3 at the Dirac point. Furthermore, we show that in periodic superlattices the location of Fano factor peaks is symmetric when the Fermi velocity vA and vB is exchanged, however by introducing quasi-periodicity the symmetry is lost. The Fano factor usually holds a universal value for a specific transport regime, which reveals that the possibility of controlling it in graphene is a notable result.

  9. Thrust generation by a heaving flexible foil: Resonance, nonlinearities, and optimality

    Science.gov (United States)

    Paraz, Florine; Schouveiler, Lionel; Eloy, Christophe

    2016-01-01

    Flexibility of marine animal fins has been thought to enhance swimming performance. However, despite numerous experimental and numerical studies on flapping flexible foils, there is still no clear understanding of the effect of flexibility and flapping amplitude on thrust generation and swimming efficiency. Here, to address this question, we combine experiments on a model system and a weakly nonlinear analysis. Experiments consist in immersing a flexible rectangular plate in a uniform flow and forcing this plate into a heaving motion at its leading edge. A complementary theoretical model is developed assuming a two-dimensional inviscid problem. In this model, nonlinear effects are taken into account by considering a transverse resistive drag. Under these hypotheses, a modal decomposition of the system motion allows us to predict the plate response amplitude and the generated thrust, as a function of the forcing amplitude and frequency. We show that this model can correctly predict the experimental data on plate kinematic response and thrust generation, as well as other data found in the literature. We also discuss the question of efficiency in the context of bio-inspired propulsion. Using the proposed model, we show that the optimal propeller for a given thrust and a given swimming speed is achieved when the actuating frequency is tuned to a resonance of the system, and when the optimal forcing amplitude scales as the square root of the required thrust.

  10. Sci-Sat AM: Radiation Dosimetry and Practical Therapy Solutions - 05: Not all geometries are equivalent for magnetic field Fano cavity tests

    Energy Technology Data Exchange (ETDEWEB)

    Malkov, Victor N.; Rogers, David W.O. [Carleton University (Canada)

    2016-08-15

    The coupling of MRI and radiation treatment systems for the application of magnetic resonance guided radiation therapy necessitates a reliable magnetic field capable Monte Carlo (MC) code. In addition to the influence of the magnetic field on dose distributions, the question of proper calibration has arisen due to the several percent variation of ion chamber and solid state detector responses in magnetic fields when compared to the 0 T case (Reynolds et al., Med Phys, 2013). In the absence of a magnetic field, EGSnrc has been shown to pass the Fano cavity test (a rigorous benchmarking tool of MC codes) at the 0.1 % level (Kawrakow, Med.Phys, 2000), and similar results should be required of magnetic field capable MC algorithms. To properly test such developing MC codes, the Fano cavity theorem has been adapted to function in a magnetic field (Bouchard et al., PMB, 2015). In this work, the Fano cavity test is applied in a slab and ion-chamber-like geometries to test the transport options of an implemented magnetic field algorithm in EGSnrc. Results show that the deviation of the MC dose from the expected Fano cavity theory value is highly sensitive to the choice of geometry, and the ion chamber geometry appears to pass the test more easily than larger slab geometries. As magnetic field MC codes begin to be used for dose simulations and correction factor calculations, care must be taken to apply the most rigorous Fano test geometries to ensure reliability of such algorithms.

  11. 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.

  12. 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.

  13. Experimental Investigation of 2:1 and 3:1 Internal Resonances in Nonlinear MEMS Arch Resonators

    KAUST Repository

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

    2016-01-01

    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. Nonlinear dynamics near resonances of a rotor-active magnetic bearings system with 16-pole legs and time varying stiffness

    Science.gov (United States)

    Wu, R. Q.; Zhang, W.; Yao, M. H.

    2018-02-01

    In this paper, we analyze the complicated nonlinear dynamics of rotor-active magnetic bearings (rotor-AMB) with 16-pole legs and the time varying stiffness. The magnetic force with 16-pole legs is obtained by applying the electromagnetic theory. The governing equation of motion for rotor-active magnetic bearings is derived by using the Newton's second law. The resulting dimensionless equation of motion for the rotor-AMB system is expressed as a two-degree-of-freedom nonlinear system including the parametric excitation, quadratic and cubic nonlinearities. The averaged equation of the rotor-AMB system is obtained by using the method of multiple scales when the primary parametric resonance and 1/2 subharmonic resonance are taken into account. From the frequency-response curves, it is found that there exist the phenomena of the soft-spring type nonlinearity and the hardening-spring type nonlinearity in the rotor-AMB system. The effects of different parameters on the nonlinear dynamic behaviors of the rotor-AMB system are investigated. The numerical results indicate that the periodic, quasi-periodic and chaotic motions occur alternately in the rotor-AMB system.

  15. 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.

  16. Nonlinear real index of refraction variations of a gas medium due to a monochromatic radiation near resonance

    International Nuclear Information System (INIS)

    Vasconcellos, J.I.C.

    1982-01-01

    The nonlinear real index of refraction variations of a gas medium due to a strong monochromatic radiation causing saturation effects is calculated. The gas is supposed to be composed of two-level molecules with which the external field is nearly resonant. It is assumed homogeneous (hard collisions, spontaneous decay) and inhomogeneous (Doppler effect) broadening mechanisms acting on the real index of refraction of the medium. The nonlinear dispersion of the medium is studied as a function of the detuning frequencies, saturation conditions and for various ratios between the homogeneous and inhomogeneous linewidths. In particular, the modification of the index of refraction due to saturation effects are emphasized. (Author) [pt

  17. Explicit Gromov-Hausdorff compactifications of moduli spaces of Kähler-Einstein Fano manifolds

    DEFF Research Database (Denmark)

    Spotti, Cristiano; Sun, Song

    We exhibit the first non-trivial concrete examples of Gromov-Hausdorff compactifications of moduli spaces of Kähler-Einstein Fano manifolds in all complex dimensions bigger than two (Fano K-moduli spaces). We also discuss potential applications to explicit study of moduli spaces of K-stable Fano...

  18. Linear and Nonlinear Response of a Rotating Tokamak Plasma to a Resonant Error-Field

    Science.gov (United States)

    Fitzpatrick, Richard

    2014-10-01

    An in-depth investigation of the effect of a resonant error-field on a rotating, quasi-cylindrical, tokamak plasma is preformed within the context of resistive-MHD theory. General expressions for the response of the plasma at the rational surface to the error-field are derived in both the linear and nonlinear regimes, and the extents of these regimes mapped out in parameter space. Torque-balance equations are also obtained in both regimes. These equations are used to determine the steady-state plasma rotation at the rational surface in the presence of the error-field. It is found that, provided the intrinsic plasma rotation is sufficiently large, the torque-balance equations possess dynamically stable low-rotation and high-rotation solution branches, separated by a forbidden band of dynamically unstable solutions. Moreover, bifurcations between the two stable solution branches are triggered as the amplitude of the error-field is varied. A low- to high-rotation bifurcation is invariably associated with a significant reduction in the width of the magnetic island chain driven at the rational surface, and vice versa. General expressions for the bifurcation thresholds are derived, and their domains of validity mapped out in parameter space. This research was funded by the U.S. Department of Energy under Contract DE-FG02-04ER-54742.

  19. Accelerated Computing in Magnetic Resonance Imaging: Real-Time Imaging Using Nonlinear Inverse Reconstruction

    Directory of Open Access Journals (Sweden)

    Sebastian Schaetz

    2017-01-01

    Full Text Available Purpose. To develop generic optimization strategies for image reconstruction using graphical processing units (GPUs in magnetic resonance imaging (MRI and to exemplarily report on our experience with a highly accelerated implementation of the nonlinear inversion (NLINV algorithm for dynamic MRI with high frame rates. Methods. The NLINV algorithm is optimized and ported to run on a multi-GPU single-node server. The algorithm is mapped to multiple GPUs by decomposing the data domain along the channel dimension. Furthermore, the algorithm is decomposed along the temporal domain by relaxing a temporal regularization constraint, allowing the algorithm to work on multiple frames in parallel. Finally, an autotuning method is presented that is capable of combining different decomposition variants to achieve optimal algorithm performance in different imaging scenarios. Results. The algorithm is successfully ported to a multi-GPU system and allows online image reconstruction with high frame rates. Real-time reconstruction with low latency and frame rates up to 30 frames per second is demonstrated. Conclusion. Novel parallel decomposition methods are presented which are applicable to many iterative algorithms for dynamic MRI. Using these methods to parallelize the NLINV algorithm on multiple GPUs, it is possible to achieve online image reconstruction with high frame rates.

  20. 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.

  1. A study on axial and torsional resonant mode matching for a mechanical system with complex nonlinear geometries

    Science.gov (United States)

    Watson, Brett; Yeo, Leslie; Friend, James

    2010-06-01

    Making use of mechanical resonance has many benefits for the design of microscale devices. A key to successfully incorporating this phenomenon in the design of a device is to understand how the resonant frequencies of interest are affected by changes to the geometric parameters of the design. For simple geometric shapes, this is quite easy, but for complex nonlinear designs, it becomes significantly more complex. In this paper, two novel modeling techniques are demonstrated to extract the axial and torsional resonant frequencies of a complex nonlinear geometry. The first decomposes the complex geometry into easy to model components, while the second uses scaling techniques combined with the finite element method. Both models overcome problems associated with using current analytical methods as design tools, and enable a full investigation of how changes in the geometric parameters affect the resonant frequencies of interest. The benefit of such models is then demonstrated through their use in the design of a prototype piezoelectric ultrasonic resonant micromotor which has improved performance characteristics over previous prototypes.

  2. Engineering non-linear resonator mode interactions in circuit QED by continuous driving: Manipulation of a photonic quantum memory

    Science.gov (United States)

    Reagor, Matthew; Pfaff, Wolfgang; Heeres, Reinier; Ofek, Nissim; Chou, Kevin; Blumoff, Jacob; Leghtas, Zaki; Touzard, Steven; Sliwa, Katrina; Holland, Eric; Albert, Victor V.; Frunzio, Luigi; Devoret, Michel H.; Jiang, Liang; Schoelkopf, Robert J.

    2015-03-01

    Recent advances in circuit QED have shown great potential for using microwave resonators as quantum memories. In particular, it is possible to encode the state of a quantum bit in non-classical photonic states inside a high-Q linear resonator. An outstanding challenge is to perform controlled operations on such a photonic state. We demonstrate experimentally how a continuous drive on a transmon qubit coupled to a high-Q storage resonator can be used to induce non-linear dynamics of the resonator. Tailoring the drive properties allows us to cancel or enhance non-linearities in the system such that we can manipulate the state stored in the cavity. This approach can be used to either counteract undesirable evolution due to the bare Hamiltonian of the system or, ultimately, to perform logical operations on the state encoded in the cavity field. Our method provides a promising pathway towards performing universal control for quantum states stored in high-coherence resonators in the circuit QED platform.

  3. SU-E-T-347: Validation of the Condensed History Algorithm of Geant4 Using the Fano Test

    International Nuclear Information System (INIS)

    Lee, H; Mathis, M; Sawakuchi, G

    2014-01-01

    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

  4. A Fano cavity test for Monte Carlo proton transport algorithms

    International Nuclear Information System (INIS)

    Sterpin, Edmond; Sorriaux, Jefferson; Souris, Kevin; Vynckier, Stefaan; Bouchard, Hugo

    2014-01-01

    Purpose: In the scope of reference dosimetry of radiotherapy beams, Monte Carlo (MC) simulations are widely used to compute ionization chamber dose response accurately. Uncertainties related to the transport algorithm can be verified performing self-consistency tests, i.e., the so-called “Fano cavity test.” The Fano cavity test is based on the Fano theorem, which states that under charged particle equilibrium conditions, the charged particle fluence is independent of the mass density of the media as long as the cross-sections are uniform. Such tests have not been performed yet for MC codes simulating proton transport. The objectives of this study are to design a new Fano cavity test for proton MC and to implement the methodology in two MC codes: Geant4 and PENELOPE extended to protons (PENH). Methods: The new Fano test is designed to evaluate the accuracy of proton transport. Virtual particles with an energy ofE 0 and a mass macroscopic cross section of (Σ)/(ρ) are transported, having the ability to generate protons with kinetic energy E 0 and to be restored after each interaction, thus providing proton equilibrium. To perform the test, the authors use a simplified simulation model and rigorously demonstrate that the computed cavity dose per incident fluence must equal (ΣE 0 )/(ρ) , as expected in classic Fano tests. The implementation of the test is performed in Geant4 and PENH. The geometry used for testing is a 10 × 10 cm 2 parallel virtual field and a cavity (2 × 2 × 0.2 cm 3 size) in a water phantom with dimensions large enough to ensure proton equilibrium. Results: For conservative user-defined simulation parameters (leading to small step sizes), both Geant4 and PENH pass the Fano cavity test within 0.1%. However, differences of 0.6% and 0.7% were observed for PENH and Geant4, respectively, using larger step sizes. For PENH, the difference is attributed to the random-hinge method that introduces an artificial energy straggling if step size is not

  5. Suppression of chaos by weak resonant excitations in a non-linear oscillator with a non-symmetric potential

    International Nuclear Information System (INIS)

    Litak, Grzegorz; Syta, Arkadiusz; Borowiec, Marek

    2007-01-01

    We examine the Melnikov criterion for transition to chaos in case of one degree of freedom non-linear oscillator with non-symmetric potential. This system, when subjected to an external periodic force, shows homoclinic transition from regular vibrations to chaos just before escape from a potential well. We focus especially on the effect of a second resonant excitation with a different phase on the system transition to chaos. We propose a way of its control

  6. Explicit and exact solutions for a generalized long-short wave resonance equations with strong nonlinear term

    International Nuclear Information System (INIS)

    Shang Yadong

    2005-01-01

    In this paper, the evolution equations with strong nonlinear term describing the resonance interaction between the long wave and the short wave are studied. Firstly, based on the qualitative theory and bifurcation theory of planar dynamical systems, all of the explicit and exact solutions of solitary waves are obtained by qualitative seeking the homoclinic and heteroclinic orbits for a class of Lienard equations. Then the singular travelling wave solutions, periodic travelling wave solutions of triangle functions type are also obtained on the basis of the relationships between the hyperbolic functions and that between the hyperbolic functions with the triangle functions. The varieties of structure of exact solutions of the generalized long-short wave equation with strong nonlinear term are illustrated. The methods presented here also suitable for obtaining exact solutions of nonlinear wave equations in multidimensions

  7. Nonlinear self-precession and wavenumber shift of electromagnetic waves under resonance and of Alfven waves in plasmas

    International Nuclear Information System (INIS)

    Bhattacharyya, B.; Chakraborty, B.

    1979-01-01

    Nonlinear corrections of a left and a right circularly polarized electromagnetic wave of the same frequency, propagating in the direction of a static and uniform magnetic field in a cold and collisionally damped two-component plasma, have been evaluated. The nonlinearly correct dispersion relation, self-generating nonlinear precessional rotation of the polarization ellipse of the wave and the shift in a wave parameter depend on linear combinations of products of the amplitude components taken two at a time and hence on the energies of the waves. Both in the low frequency resonance (that is when the ion cyclotron frequency equals the wave frequency) and in the high frequency resonance (that is when the electron cyclotron frequency equals the wave frequency), the self-precessional rate and wavenumber shift are found to be large and so have the possibility of detection in laboratory experiments. Moreover, for the limit leading to Alfven waves, these nonlinear effects have been found to have some interesting and significant properties. (Auth.)

  8. Nonlinear primary resonance of micro/nano-beams made of nanoporous biomaterials incorporating nonlocality and strain gradient size dependency

    Science.gov (United States)

    Sahmani, S.; Aghdam, M. M.

    2018-03-01

    A wide range of biological applications such as drug delivery, biosensors and hemodialysis can be provided by nanoporous biomaterials due to their uniform pore size as well as considerable pore density. In the current study, the size dependency in the nonlinear primary resonance of micro/nano-beams made of nanoporous biomaterials is anticipated. To accomplish this end, a refined truncated cube is introduced to model the lattice structure of nanoporous biomaterial. Accordingly, analytical expressions for the mechanical properties of material are derived as functions of pore size. After that, based upon a nonlocal strain gradient beam model, the size-dependent nonlinear Duffing type equation of motion is constructed. The Galerkin technique together with the multiple time-scales method is employed to obtain the nonlocal strain gradient frequency-response and amplitude-response related to the nonlinear primary resonance of a micro/nano-beam made of the nanoporous biomaterial with different pore sizes. It is indicated that the nonlocality causes to decrease the response amplitudes associated with the both bifurcation points of the jump phenomenon, while the strain gradient size dependency causes to increase them. Also, it is found that increasing the pore size leads to enhance the nonlinearity, so the maximum deflection of response occurs at higher excitation frequency.

  9. Equivalent circuit method research of resonant magnetoelectric characteristic in magnetoelectric laminate composites using nonlinear magnetostrictive constitutive model

    International Nuclear Information System (INIS)

    Zhou, Hao-Miao; Li, Chao; Xuan, Li-Ming; Zhao, Ji-Xiang; Wei, Jing

    2011-01-01

    This paper analyzes the magnetoelectric (ME) response around the resonance frequency in the magnetostrictive/piezoelectric/magnetostrictive (MPM) magnetoelectric laminate composites. Following the equivalent circuit method and considering the mechanical loss, we select the nonlinear magnetostrictive constitutive model to present a novel explicit nonlinear expression for the resonant magnetoelectric (ME) coefficient of the magnetoelectric laminate composites. Compared with the experimental results, the predicted resonant ME coefficient of the explicit expression shows a good agreement both qualitatively and quantitatively. Also, when the electromechanical coupling factor of the piezoelectric material, k 31 p , is small, this explicit expression can be reduced to the existing model. On this basis, this paper considers and predicts the magnetoelectric conversion characteristics of the magnetoelectric laminate composites, calculates and analyzes the influences of the thickness ratio of magnetostrictive layer and piezoelectric material, bias magnetic field, and saturation magnetostrictive coefficient on the resonant ME coefficient. This research can provide a theoretical basis for the preparation of magnetoelectric devices with good magnetoelectric conversion characteristics, such as magnetoelectric sensors, energy harvesting transducers, microwave devices etc

  10. Twin "Fano-Snowflakes" Over the Smallest Ring of Ternions

    Czech Academy of Sciences Publication Activity Database

    Saniga, M.; Havlicek, H.; Planat, M.; Pracna, Petr

    2008-01-01

    Roč. 4, - (2008), 050-1-7 ISSN 1815-0659 Institutional research plan: CEZ:AV0Z40400503 Keywords : geometry over rings * non-communicative ring of order eight * Fano plane Subject RIV: CF - Physical ; Theoretical Chemistry

  11. Large signal simulation of photonic crystal Fano laser

    DEFF Research Database (Denmark)

    Zali, Aref Rasoulzadeh; Yu, Yi; Moravvej-Farshi, Mohammad Kazem

    2017-01-01

    be modulated at frequencies exceeding 1 THz which is much higher than its corresponding relaxation oscillation frequency. Large signal simulation of the Fano laser is also investigated based on pseudorandom bit sequence at 0.5 Tbit/s. It shows eye patterns are open at such high modulation frequency, verifying...

  12. Simple classical model for Fano statistics in radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, David V. [Pacific Northwest National Laboratory, National Security Division - Radiological and Chemical Sciences Group PO Box 999, Richland, WA 99352 (United States)], E-mail: David.Jordan@pnl.gov; Renholds, Andrea S.; Jaffe, John E.; Anderson, Kevin K.; Rene Corrales, L.; Peurrung, Anthony J. [Pacific Northwest National Laboratory, National Security Division - Radiological and Chemical Sciences Group PO Box 999, Richland, WA 99352 (United States)

    2008-02-01

    A simple classical model that captures the essential statistics of energy partitioning processes involved in the creation of information carriers (ICs) in radiation detectors is presented. The model pictures IC formation from a fixed amount of deposited energy in terms of the statistically analogous process of successively sampling water from a large, finite-volume container ('bathtub') with a small dipping implement ('shot or whiskey glass'). The model exhibits sub-Poisson variance in the distribution of the number of ICs generated (the 'Fano effect'). Elementary statistical analysis of the model clarifies the role of energy conservation in producing the Fano effect and yields Fano's prescription for computing the relative variance of the IC number distribution in terms of the mean and variance of the underlying, single-IC energy distribution. The partitioning model is applied to the development of the impact ionization cascade in semiconductor radiation detectors. It is shown that, in tandem with simple assumptions regarding the distribution of energies required to create an (electron, hole) pair, the model yields an energy-independent Fano factor of 0.083, in accord with the lower end of the range of literature values reported for silicon and high-purity germanium. The utility of this simple picture as a diagnostic tool for guiding or constraining more detailed, 'microscopic' physical models of detector material response to ionizing radiation is discussed.

  13. Determination of nonlinear nanomechanical resonator-qubit coupling coefficient in a hybrid quantum system.

    Science.gov (United States)

    Geng, Qi; Zhu, Ka-Di

    2016-07-10

    We have theoretically investigated a hybrid system that is composed of a traditional optomechanical component and an additional charge qubit (Cooper pair box) that induces a new nonlinear interaction. It is shown that the peak in optomechanically induced transparency has been split by the new nonlinear interaction, and the width of the splitting is proportional to the coupling coefficient of this nonlinear interaction. This may give a way to measure the nanomechanical oscillator-qubit coupling coefficient in hybrid quantum systems.

  14. 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

  15. Resonantly enhanced nonlinear optics in semiconductor quantum wells: An application to sensitive infrared detection

    International Nuclear Information System (INIS)

    Yelin, S.F.; Hemmer, P.R.

    2002-01-01

    A novel class of coherent nonlinear optical phenomena, involving induced transparency in semiconductor quantum wells, is considered in the context of a particular application to sensitive long-wavelength infrared detection. It is shown that the strongest decoherence mechanisms can be suppressed or mitigated, resulting in substantial enhancement of nonlinear optical effects in semiconductor quantum wells

  16. Nonlinear Stimulated Raman Exact Passage by Resonance-Locked Inverse Engineering

    Science.gov (United States)

    Dorier, V.; Gevorgyan, M.; Ishkhanyan, A.; Leroy, C.; Jauslin, H. R.; Guérin, S.

    2017-12-01

    We derive an exact and robust stimulated Raman process for nonlinear quantum systems driven by pulsed external fields. The external fields are designed with closed-form expressions from the inverse engineering of a given efficient and stable dynamics. This technique allows one to induce a controlled population inversion which surpasses the usual nonlinear stimulated Raman adiabatic passage efficiency.

  17. 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

  18. Real-time cardiovascular magnetic resonance at high temporal resolution: radial FLASH with nonlinear inverse reconstruction.

    Science.gov (United States)

    Zhang, Shuo; Uecker, Martin; Voit, Dirk; Merboldt, Klaus-Dietmar; Frahm, Jens

    2010-07-08

    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. 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. 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 degrees 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. Though awaiting thorough clinical evaluation, this work describes a robust and flexible acquisition and reconstruction technique for

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

    KAUST Repository

    Amin, M.; Farhat, Mohamed; Bagci, Hakan

    2013-01-01

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

  20. 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.

  1. 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.

  2. Non-classical nonlinear feature extraction from standard resonance vibration data for damage detection.

    Science.gov (United States)

    Eiras, J N; Monzó, J; Payá, J; Kundu, T; Popovics, J S

    2014-02-01

    Dynamic non-classical nonlinear analyses show promise for improved damage diagnostics in materials that exhibit such structure at the mesoscale, such as concrete. In this study, nonlinear non-classical dynamic material behavior from standard vibration test data, using pristine and frost damaged cement mortar bar samples, is extracted and quantified. The procedure is robust and easy to apply. The results demonstrate that the extracted nonlinear non-classical parameters show expected sensitivity to internal damage and are more sensitive to changes owing to internal damage levels than standard linear vibration parameters.

  3. Molding of plasmonic resonances in metallic nanostructures: Dependence of the non-linear electric permittivity on system size and temperature

    KAUST Repository

    Alabastri, A.; Tuccio, S.; Giugni, A.; Toma, A.; Liberale, Carlo; Das, G.; Angelis, F.D.; Fabrizio, E.D.; Zaccaria, R.P.

    2013-01-01

    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.

  4. Long-distance pulse propagation on high-frequency dissipative nonlinear transmission lines/resonant tunneling diode line cascaded maps

    International Nuclear Information System (INIS)

    Klofai, Yerima; Essimbi, B Z; Jaeger, D

    2011-01-01

    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.

  5. 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.

  6. 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.

  7. Near resonant and nonresonant third-order optical nonlinearities of colloidal InP/ZnS quantum dots

    Science.gov (United States)

    Wang, Y.; Yang, X.; He, T. C.; Gao, Y.; Demir, H. V.; Sun, X. W.; Sun, H. D.

    2013-01-01

    We have investigated the third-order optical nonlinearities of high-quality colloidal InP/ZnS core-shell quantum dots (QDs) using Z-scan technique with femtosecond pulses. The two-photon absorption cross-sections as high as 6.2 × 103 GM are observed at 800 nm (non-resonant regime) in InP/ZnS QDs with diameter of 2.8 nm, which is even larger than those of CdSe, CdS, and CdTe QDs at similar sizes. Furthermore, both of the 2.2 nm and 2.8 nm-sized InP/ZnS QDs exhibit strong saturable absorption in near resonant regime, which is attributed to large exciton Bohr radius in this material. These results strongly suggest the promising potential of InP/ZnS QDs for widespread applications, especially in two-photon excited bio-imaging and saturable absorbing.

  8. 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.

  9. 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)

  10. Twin ''Fano-Snowflakes'' over the Smallest Ring of Ternions

    Directory of Open Access Journals (Sweden)

    Metod Saniga

    2008-06-01

    Full Text Available Given a finite associative ring with unity, R, any free (left cyclic submodule (FCS generated by a unimodular (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.

  11. Nonlinear narrow Doppler-free resonances for optical transitions and annihilation radiation of a positronium atom

    International Nuclear Information System (INIS)

    Letokhov, V.S.; Minogin, V.G.

    1976-01-01

    The possibilities of obtaining narrow resonances without the Doppler broadening for transition between the fine structure levels of the ground and first excited states of a positronium atom are considered. An analysis is carried out of the conditions required for observation of the narrow resonances of saturation of single quantum absorption in the 1S-2P transitions and observation of narrow two-photon absorption resonances in the 1S-2S transitions. It is shown that narrow 2γ annihilation radiation lines of a positronium atom may be obtained with a width much smaller than the Doppler one

  12. Suppression of nonlinear frequency-sweeping of resonant interchange modes in a magnetic dipole with applied radio frequency fields

    International Nuclear Information System (INIS)

    Maslovsky, D.; Levitt, B.; Mauel, M. E.

    2003-01-01

    Interchange instabilities excited by energetic electrons trapped by a magnetic dipole nonlinearly saturate and exhibit complex, coherent spectral characteristics and frequency sweeping [H. P. Warren and M. E. Mauel, Phys. Plasmas 2, 4185 (1995)]. When monochromatic radio frequency (rf) fields are applied in the range of 100-1000 MHz, the saturation behavior of the interchange instability changes dramatically. For applied fields of sufficient intensity and pulse-length, coherent interchange fluctuations are suppressed and frequency sweeping is eliminated. When rf fields are switched off, coherent frequency sweeping reappears. Since low frequency interchange instabilities preserve the electron's first and second adiabatic invariants, these observations can be interpreted as resulting from nonlinear resonant wave-particle interactions described within a particle phase-space, (ψ,φ), comprised of the third adiabatic invariant and the azimuthal angle. Self-consistent numerical simulation is used to study (1) the nonlinear development of the instability, (2) the radial mode structure of the interchange instability, and (3) the suppression of frequency sweeping. When the applied rf heating is modeled as an 'rf collisionality', the simulation reproduces frequency sweeping suppression and suggests an explanation for the observations that is consistent with Berk and co-workers [H. L. Berk et al., Phys. Plasmas 6, 3102 (1999)

  13. On the Effect of Thermoelastic Damping in Nonlinear Micro Electro Mechanical Resonators using Differential Quadrature Method

    Directory of Open Access Journals (Sweden)

    A. Karami Mohammadi

    2015-07-01

    Full Text Available : In this paper, a nonlinear model of clamped-clamped microbeam actuated by electrostatic load with stretching and thermoelastic effects is presented. Free vibration frequency is calculated by discretization based on DQ method. Frequency is a complex value due to the thermoelastic effect that dissipates the energy. By separating the real and imaginary parts of frequency, quality factor of thermoelastic damping is calculated. Both stretching and thermoelastic effects are validated against the results of the reference papers. The variations of thermoelastic damping versus elasticity modulus, coefficient of thermal expansion and geometrical parameters such as thickness, gap distance, and length are investigated and these results are compared in the linear and nonlinear models for high values of voltage. Also, this paper shows that since for high values of electrostatic voltage the linear model reveals a large error for calculating the thermoelastic damping, the nonlinear model should be used for this purpose.

  14. 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.

  15. Dispersion of the resonant second order nonlinearity in 2D semiconductors probed by femtosecond continuum pulses

    Directory of Open Access Journals (Sweden)

    Mohammad Mokim

    2017-10-01

    Full Text Available We demonstrate an effective microspectroscopy technique by tracing the dispersion of second order nonlinear susceptibility (χ(2 in a monolayer tungsten diselenide (WSe2. The χ(2 dispersion obtained with better than 3 meV photon energy resolution showed peak value being within 6.3-8.4×10-19 m2/V range. We estimate the fundamental bandgap to be at 2.2 eV. Sub-structure in the χ(2 dispersion reveals a contribution to the nonlinearity due to exciton transitions with exciton binding energy estimated to be at 0.7 eV.

  16. 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 N......:YVO4 laser, generating a SFG beam at 488 nm. The ECDL have MH^2=1.9 and MV^2=2.4 and the solid-state laser has M^2...

  17. Nonlinear dynamics of spring softening and hardening in folded-mems comb drive resonators

    KAUST Repository

    Elshurafa, Amro M.; Khirallah, Kareem; Tawfik, Hani H.; Emira, Ahmed; Abdel Aziz, Ahmed K S; Sedky, Sherif M.

    2011-01-01

    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

  18. Nonlinear saturation of non-resonant internal instabilities in a straight spheromak

    International Nuclear Information System (INIS)

    Park, W.; Jardin, S.C.

    1982-04-01

    An initial value numerical solution of the time dependent nonlinear ideal magnetohydrodynamic equations demonstrates that spheromak equilibria which are linearly unstable to nonresonant helical internal perturbations saturate at low amplitude without developing singularities. These instabilities thus represent the transition from an axisymmetric to a non-axisymmetric equilibrium state, caused by a peaking of the current density

  19. Fano-Kondo and the Kondo box regimes crossover in a quantum dot coupled to a quantum box

    Science.gov (United States)

    Apel, Victor M.; Orellana, Pedro A.; Pacheco, Monica; Anda, Enrique V.

    2013-12-01

    In this work, we study the Kondo effect of a quantum dot (QD) connected to leads and to a discrete set of one-particle states provided by a quantum box represented by a quantum ring (QR) pierced by a magnetic flux side attached to the QD. The interplay between the bulk Kondo effect and the so-called Kondo box regime is studied. In this system the QR energies can be continuously modified by the application of the magnetic field. The crossover between these two regimes is analyzed by changing the connection of the QD to the QR from the weak to the strong coupling regime. In the weak coupling regime, the differential conductance develops a sequence of Fano-Kondo anti-resonances due to destructive interference between the discrete quantum ring levels and the conducting Kondo channel provided by the leads. In the strong coupling regime the differential conductance has very sharp resonances when one of the Kondo discrete sub-levels characterizing the Kondo box is tuned by the applied potential. The conductance, the current fluctuations and the Fano coefficient result as being the relevant physical magnitudes to be analyzed to reveal the physical properties of these two Kondo regimes and the crossover region between them. The results were obtained by using the slave boson mean field theory (SBMFT).

  20. Energy and momentum balance in nonlinear interactions of resonant and nonresonant waves in turbulent plasmas

    International Nuclear Information System (INIS)

    Vladimirov, S.V.; Nambu, Mitsuhiro

    1995-01-01

    From investigations of resonant interactions of particles and waves in turbulent plasmas it is well known that not only resonant particles contribute to expressions for the wave energy and momentum providing conservation of these quantities for closed systems. In particular, it was demonstrated that contribution of the nonresonant particles is very important for the energy conservation in the quasilinear theory: although the nonresonant terms do not appear in the diffusion equation, they contribute to the wave energy (and, in general, wave momentum) ensuring the conservation of total energy (and momentum) in the system. We note that the real part of the dielectric permittivity ε ωk as well as the wave frequency ω k of the resonant waves do not depend on time in the quasilinear approximation since only nonresonant particles (which distribution is constant) contribute to them. The resonant wave amplitude, however, is the function on time, and changing of the wave energy is completely balanced by the corresponding change of the resonant particle energy. If in the system there are only nonresonant waves, and it is closed (i.e., there is no energy exchange with some external sources or sinks), the system is stationary and the nonresonant wave as well as particle energy are not changing

  1. Effect of nonlinearity of spin interaction with electromagnetic resonance field on characteristics of polarized nuclear target

    International Nuclear Information System (INIS)

    Vertij, A.A.; Gavrilov, S.P.; Shestopalov, V.P.

    1990-01-01

    Interaction of incident nuclear particle beam with J = 1/2 (neutrons) spin and (J = 1/2) protons with the target substance is considered. It is shown that neutron polarization at the target exit and neutron transparency (G) of the target depend significantly on incident wave amplitude level and physical parameter values which characterize the target, such as target temperature, resonator mirror reflection factor, number of spins interacting with the field, etc. Under interaction of neutrons with a target resonator which features a high mirror reflection factor and low losses for absorption which is not related to magnetic dipole absorption, a bistable response of neutron polarization and G manifests itself. 1 ref

  2. Double-resonant processes in x.sup.20.sup. nonlinear periodic media

    Czech Academy of Sciences Publication Activity Database

    Konotop, V. V.; Kuzmiak, Vladimír

    2000-01-01

    Roč. 17, č. 11 (2000), s. 1874-1883 ISSN 0740-3224 Grant - others:Fundo European de Desenvolvimento Regional and Program PRAXIS XXI(PT) PRAXIS/2/2.1/FIS/176/94 Institutional research plan: CEZ:AV0Z2067918 Keywords : nonlinear media * electromagnetic wave propagation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.943, year: 2000

  3. Laser photo-reflectance characterization of resonant nonlinear electro-refraction in thin semiconductor films

    International Nuclear Information System (INIS)

    Chism, Will; Cartwright, Jason

    2012-01-01

    Photo-reflectance (PR) measurements provide a non-contact means for the precise characterization of semiconductor electronic properties. In this paper, we investigate the use of a laser beam as the probe beam in the PR setup. In this case it is seen that the nonlinear refraction is responsible for the amplitude change of the reflected probe field, whereas the phase change is due to nonlinear absorption. The open aperture condition may then be used to eliminate the spatial phase at the detector, thereby isolating the electro-refractive contribution to the PR signal. This greatly simplifies the PR analysis and allows absolute measurements of electro-refraction in thin semiconductor films. We report the application of the laser PR technique to characterize physical strain in thin silicon on silicon-germanium films. - Highlights: ► We describe the theory of laser photoreflectance. ► Laser photoreflectance is used to independently characterize nonlinear refraction. ► We report the characterization of strain in thin strained silicon films.

  4. Observation of self-pulsing in singly resonant optical second-harmonic generation with competing nonlinearities

    DEFF Research Database (Denmark)

    Bache, Morten; Lodahl, Peter; Mamaev, Alexander V.

    2002-01-01

    We predict and experimentally observe temporal self-pulsing in singly resonant intracavity second-harmonic generation under conditions of simultaneous parametric oscillation. The threshold for self-pulsing as a function of cavity tuning and phase mismatch are found from analysis of a three...

  5. 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 ...

  6. Amplitude calibration of 2D mechanical resonators by nonlinear optical transduction

    NARCIS (Netherlands)

    Dolleman, R.J.; Davidovikj, D.; van der Zant, H.S.J.; Steeneken, P.G.

    2017-01-01

    Contactless characterization of mechanical resonances using Fabry-Perot interferometry is a powerful tool to study the mechanical and dynamical properties of atomically thin membranes. However, amplitude calibration is often not performed or only possible by making assumptions on the device

  7. Large resonant third-order optical nonlinearity of thin film containing ...

    Indian Academy of Sciences (India)

    2011-11-08

    Nov 8, 2011 ... resonant conditions. The temporal profile of DFWM signal was obtained with a time resolution of 0·3 ps (FWHM), ... in the probability of absorption and emission of light. In the ... The wavelength of the laser was adjusted to 760 nm. .... distribution of different arrangements) of the dye molecules on the glass ...

  8. 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.

  9. Lineshape Engineering in an All-Pass Ring Resonator with Backreflection Coupled to a Symmetrical Fabry-Perot Resonator

    KAUST Repository

    Melnikov, Vasily; Roqan, Iman S.

    2012-01-01

    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.

  10. Ultra-fast all-optical plasmonic switching in near infra-red spectrum using a Kerr nonlinear ring resonator

    Science.gov (United States)

    Nurmohammadi, Tofiq; Abbasian, Karim; Yadipour, Reza

    2018-03-01

    In this paper, an all-optical plasmonic switch based on metal-insulator-metal (MIM) nanoplasmonic waveguide with a Kerr nonlinear ring resonator is introduced and studied. Two-dimensional simulations utilizing the finite-difference time-domain algorithm are used to demonstrate an apparent optical bistability and significant switching mechanisms (in enabled-low condition: T(ON/OFF) =21.9 and in enabled-high condition: T(ON/OFF) =24.9) of the signal light arisen by altering the pump-light intensity. The proposed all-optical switching demonstrates femtosecond-scale feedback time (90 fs) and then ultra-fast switching can be achieved. The offered all-optical switch may recognize potential significant applications in integrated optical circuits.

  11. 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.

  12. 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.

  13. Regimes 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 property exclusive to macroscopic laser systems until recently, where self-pulsing laser operation was demonstrated experimentally and theoretically in a microscopic photonic crystal Fano laser [1]. We now provide a detailed theoretical analysis of the self......-pulsing mechanism and laser characteristics with numerical simulations to demonstrate the parameter dependence of the self-pulsing regime and its limitations, indicating how the design may be optimised for applications in e.g. integrated on-chip communication systems....

  14. Geometry of minimal rational curves on Fano manifolds

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, J -M [Korea Institute for Advanced Study, Seoul (Korea, Republic of)

    2001-12-15

    This lecture is an introduction to my joint project with N. Mok where we develop a geometric theory of Fano manifolds of Picard number 1 by studying the collection of tangent directions of minimal rational curves through a generic point. After a sketch of some historical background, the fundamental object of this project, the variety of minimal rational tangents, is defined and various examples are examined. Then some results on the variety of minimal rational tangents are discussed including an extension theorem for holomorphic maps preserving the geometric structure. Some applications of this theory to the stability of the tangent bundles and the rigidity of generically finite morphisms are given. (author)

  15. 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.

  16. Dichroic mirror embedded in a submicrometer waveguide for enhanced resonant nonlinear optical devices.

    Science.gov (United States)

    Scaccabarozzi, Luigi; Fejer, M M; Huo, Yijie; Fan, Shanhui; Yu, Xiaojun; Harris, James S

    2006-11-15

    We report the design, fabrication and characterization of novel dichroic mirrors embedded in a tightly confining AlGaAs/Al(x)O(y) waveguide. Reflection at the first-harmonic wavelength as high as 93% is achieved, while high transmission is maintained at the second-harmonic wavelength. The measured cavity spectrum is in excellent agreement with finite-difference time-domain simulations. Such a mirror is essential for achieving resonant enhancement of second-harmonic generation.

  17. Stochastic resonance in a piecewise nonlinear model driven by multiplicative non-Gaussian noise and additive white noise

    Science.gov (United States)

    Guo, Yongfeng; Shen, Yajun; Tan, Jianguo

    2016-09-01

    The phenomenon of stochastic resonance (SR) in a piecewise nonlinear model driven by a periodic signal and correlated noises for the cases of a multiplicative non-Gaussian noise and an additive Gaussian white noise is investigated. Applying the path integral approach, the unified colored noise approximation and the two-state model theory, the analytical expression of the signal-to-noise ratio (SNR) is derived. It is found that conventional stochastic resonance exists in this system. From numerical computations we obtain that: (i) As a function of the non-Gaussian noise intensity, the SNR is increased when the non-Gaussian noise deviation parameter q is increased. (ii) As a function of the Gaussian noise intensity, the SNR is decreased when q is increased. This demonstrates that the effect of the non-Gaussian noise on SNR is different from that of the Gaussian noise in this system. Moreover, we further discuss the effect of the correlation time of the non-Gaussian noise, cross-correlation strength, the amplitude and frequency of the periodic signal on SR.

  18. A hybrid filter to mitigate harmonics caused by nonlinear load and resonance caused by power factor correction capacitor

    Science.gov (United States)

    Adan, N. F.; Soomro, D. M.

    2017-01-01

    Power factor correction capacitor (PFCC) is commonly installed in industrial applications for power factor correction (PFC). With the expanding use of non-linear equipment such as ASDs, power converters, etc., power factor (PF) improvement has become difficult due to the presence of harmonics. The resulting capacitive impedance of the PFCC may form a resonant circuit with the source inductive reactance at a certain frequency, which is likely to coincide with one of the harmonic frequency of the load. This condition will trigger large oscillatory currents and voltages that may stress the insulation and cause subsequent damage to the PFCC and equipment connected to the power system (PS). Besides, high PF cannot be achieved due to power distortion. This paper presents the design of a three-phase hybrid filter consisting of a single tuned passive filter (STPF) and shunt active power filter (SAPF) to mitigate harmonics and resonance in the PS through simulation using PSCAD/EMTDC software. SAPF was developed using p-q theory. The hybrid filter has resulted in significant improvement on both total harmonic distortion for voltage (THDV) and total demand distortion for current (TDDI) with maximum values of 2.93% and 9.84% respectively which were within the recommended IEEE 519-2014 standard limits. Regarding PF improvement, the combined filters have achieved PF close to desired PF at 0.95 for firing angle, α values up to 40°.

  19. Analysis and experiments on Fano interference using a 2D metamaterial cavity for field localized wireless power transfer

    International Nuclear Information System (INIS)

    Pham, Thanh Son; Ranaweera, Aruna Kumara; Ngo, Duc Viet; Lee, Jong-Wook

    2017-01-01

    To meet both safety and efficiency demands of future wireless power transfer (WPT) systems, field leakage to the nearby environment should be controlled below a certain level. Therefore, field localization is one of the key issues in advanced WPT systems. Recently, metamaterials have shown great potential for enhanced control of electromagnetic propagation in various environments. In this work, we investigate a locally modified metamaterial to create a two-dimensional (2D) cavity for field localization at a sub-wavelength scale. We also show that the field localization in the cavity can be explained using Fano-type interference. We believe that this is one of the first works demonstrating that Fano-type interference can be applied for resonance-coupled mid-range WPT. Using the proposed approach, we achieve a localized WPT in a region that is eight times smaller than that of a transmit coil. At a distance of 0.6 meters, the measured efficiency is 56.5%, which represents a six-fold and two-fold enhancement compared to free space and uniform metamaterial slabs, respectively. (paper)

  20. Analysis and experiments on Fano interference using a 2D metamaterial cavity for field localized wireless power transfer

    Science.gov (United States)

    Son Pham, Thanh; Kumara Ranaweera, Aruna; Viet Ngo, Duc; Lee, Jong-Wook

    2017-08-01

    To meet both safety and efficiency demands of future wireless power transfer (WPT) systems, field leakage to the nearby environment should be controlled below a certain level. Therefore, field localization is one of the key issues in advanced WPT systems. Recently, metamaterials have shown great potential for enhanced control of electromagnetic propagation in various environments. In this work, we investigate a locally modified metamaterial to create a two-dimensional (2D) cavity for field localization at a sub-wavelength scale. We also show that the field localization in the cavity can be explained using Fano-type interference. We believe that this is one of the first works demonstrating that Fano-type interference can be applied for resonance-coupled mid-range WPT. Using the proposed approach, we achieve a localized WPT in a region that is eight times smaller than that of a transmit coil. At a distance of 0.6 meters, the measured efficiency is 56.5%, which represents a six-fold and two-fold enhancement compared to free space and uniform metamaterial slabs, respectively.

  1. Periodic Forcing of Inhibition-Stabilized Networks: Nonlinear Resonances and Phase-Amplitude Coupling

    Science.gov (United States)

    Veltz, Romain; Sejnowski, Terrence J.

    2016-01-01

    Inhibition-stabilized networks (ISNs) are neural architectures with strong positive feedback among pyramidal neurons balanced by strong negative feedback from inhibitory interneurons, a circuit element found in the hippocampus and the primary visual cortex. In their working regime, ISNs produce damped oscillations in the γ-range in response to inputs to the inhibitory population. In order to understand the properties of interconnected ISNs, we investigated periodic forcing of ISNs. We show that ISNs can be excited over a range of frequencies and derive properties of the resonance peaks. In particular, we studied the phase-locked solutions, the torus solutions, and the resonance peaks. Periodically forced ISNs respond with (possibly multistable) phase-locked activity, whereas networks with sustained intrinsic oscillations respond more dynamically to periodic inputs with tori. Hence, the dynamics are surprisingly rich, and phase effects alone do not adequately describe the network response. This strengthens the importance of phaseamplitude coupling as opposed to phase-phase coupling in providing multiple frequencies for multiplexing and routing information. PMID:26496044

  2. 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...

  3. Observation of Fano-Type Interference in a Coupled Cavity-Atom System

    International Nuclear Information System (INIS)

    Cheng Yong; Tan Zheng; Wang Jin; Zhan Ming-Sheng; Zhu Yi-Fu

    2016-01-01

    We present the experimental observation of the Fano-type interference in a coupled cavity-atom system by confining the laser-cooled "8"5Rb atoms in an optical cavity. The asymmetric Fano profile is obtained through quantum interference in a three-level atomic system coherently coupled to a single mode cavity field. The observed Fano profile can be explained by the interference between the intra-cavity dark state and the polariton state of the coupled cavity-atom system. The possible applications of our observations include all-optical switching, optical sensing and narrow band optical filters. (paper)

  4. A new generalized exponential rational function method to find exact special solutions for the resonance nonlinear Schrödinger equation

    Science.gov (United States)

    Ghanbari, Behzad; Inc, Mustafa

    2018-04-01

    The present paper suggests a novel technique to acquire exact solutions of nonlinear partial differential equations. The main idea of the method is to generalize the exponential rational function method. In order to examine the ability of the method, we consider the resonant nonlinear Schrödinger equation (R-NLSE). Many variants of exact soliton solutions for the equation are derived by the proposed method. Physical interpretations of some obtained solutions is also included. One can easily conclude that the new proposed method is very efficient and finds the exact solutions of the equation in a relatively easy way.

  5. Plasmonic properties of gold nanoparticles on silicon substrates: Understanding Fano-like spectra observed in reflection

    Science.gov (United States)

    Bossard-Giannesini, Léo; Cruguel, Hervé; Lacaze, Emmanuelle; Pluchery, Olivier

    2016-09-01

    Gold nanoparticles (AuNPs) are known for their localized surface plasmon resonance (LSPR) that can be measured with UV-visible spectroscopy. AuNPs are often deposited on silicon substrates for various applications, and the LSPR is measured in reflection. In this case, optical spectra are measured by surface differential reflectance spectroscopy (SDRS) and the absorbance exhibits a negative peak. This article studies both experimentally and theoretically on the single layers of 16 nm diameter spherical gold nanoparticles (AuNPs) grafted on silicon. The morphology and surface density of AuNPs were investigated by atomic force microscopy (AFM). The plasmon response in transmission on the glass substrate and in reflection on the silicon substrate is described by an analytical model based on the Fresnel equations and the Maxwell-Garnett effective medium theory (FMG). The FMG model shows a strong dependence to the incidence angle of the light. At low incident angles, the peak appears negatively with a shallow intensity, and at angles above 30°, the usual positive shape of the plasmon is retrieved. The relevance of the FMG model is compared to the Mie theory within the dipolar approximation. We conclude that no Fano effect is responsible for this derivative shape. An easy-to-use formula is derived that agrees with our experimental data.

  6. Distortion of He(2l2l') Fano lineshapes by strong post-collision interaction in H+-He collisions

    International Nuclear Information System (INIS)

    Moretto-Capelle, P.; Benhenni, M.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A.

    1996-01-01

    The three-body post-collisional interaction (PCI) between the scattered proton, recoil target ion and emitted electron has been investigated by electron spectrometry near the 2l2l' helium resonances, in the 20-100 keV energy range (V p 0.9-2 au). Particular attention has been paid to the PCI deformations of the Fano lineshapes when V-vector'' p ≅ V-vector e (2l2l'). Their angle and collision velocity dependences have been studied for the first time experimentally. A large variety of lineshapes have been observed, all of them successfully described by a single formula. At the lowest proton velocities the rescattering effect (also called Coulomb two-path scattering) is seen. (Author)

  7. Noise and Fano-Factor Control in AC-Driven Aharonov-Casher Ring

    Directory of Open Access Journals (Sweden)

    Zein W. A.

    2011-01-01

    Full Text Available The spin dependent current and Fano factor of Aharonov-Casher semiconducting ring is investigated under the effect of microwave, infrared, ultraviolet radiation and magnetic field. Both the average current and the transport noise (Fano factor characteristics are expressed in terms of the tunneling probability for the respective scattering channels. For spin transport induced by microwave and infrared radiation, a random oscillatory behavior of the Fano factor is observed. These oscillations are due to constructive and destructive spin interference effects. While for the case of ultraviolet radiation, the Fano factor becomes constant. This is due to that the oscillations has been washed out by phase averaging (i.e. ensemble dephasing over the spin transport channels. The present investigation is very important for quantum computing and information processing.

  8. Noise and Fano-factor Control in AC-Driven Aharonov-Casher Ring

    Directory of Open Access Journals (Sweden)

    Phillips A. H.

    2011-01-01

    Full Text Available The spin dependent current and Fano factor of Aharonov-Casher semiconducting ring is investigated under the effect of microwave, infrared, ultraviolet radiation and magnetic field. Both the average current and the transport noise (Fano factor characteristics are expressed in terms of the tunneling probability for the respective scattering channels. For spin transport induced by microwave and infrared radiation, a random oscillatory behavior of the Fano factor is observed. These oscillations are due to constructive and destructive spin interference effects. While for the case of ultraviolet radiation, the Fano factor becomes constant. This is due to that the oscillations has been washed out by phase averaging (i.e. ensemble dephasing over the spin transport channels. The present investigation is very important for quantum computing and information processing.

  9. Resonance

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2014-01-01

    A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....

  10. Inducing Strong Non-Linearities in a Phonon Trapping Quartz Bulk Acoustic Wave Resonator Coupled to a Superconducting Quantum Interference Device

    Directory of Open Access Journals (Sweden)

    Maxim Goryachev

    2018-04-01

    Full Text Available A quartz Bulk Acoustic Wave resonator is designed to coherently trap phonons in such a way that they are well confined and immune to suspension losses so they exhibit extremely high acoustic Q-factors at low temperature, with Q × f products of order 10 18 Hz. In this work we couple such a resonator to a Superconducting Quantum Interference Device (SQUID amplifier and investigate effects in the strong signal regime. Both parallel and series connection topologies of the system are investigated. 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 in the strong signal regime.

  11. Optical Realization of Double-Continuum Fano Interference and Coherent Control in Plasmonic Metasurfaces

    Science.gov (United States)

    Arju, Nihal; Ma, Tzuhsuan; Khanikaev, Alexander; Purtseladze, David; Shvets, Gennady

    2015-06-01

    Classical realization of a ubiquitous quantum mechanical phenomenon of double-continuum Fano interference using metasurfaces is experimentally demonstrated by engineering the near-field interaction between two bright and one dark plasmonic modes. The competition between the bright modes, one of them effectively suppressing the Fano interference for the orthogonal light polarization, is discovered. Coherent control of optical energy concentration and light absorption by the ellipticity of the incident light is theoretically predicted.

  12. Mode-locking peculiarities in an all-fiber erbium-doped ring ultrashort pulse laser with a highly-nonlinear resonator

    Science.gov (United States)

    Dvoretskiy, Dmitriy A.; Sazonkin, Stanislav G.; Kudelin, Igor S.; Orekhov, Ilya O.; Pnev, Alexey B.; Karasik, Valeriy E.; Denisov, Lev K.

    2017-12-01

    Today ultrashort pulse (USP) fiber lasers are in great demand in a frequency metrology field, THz pulse spectroscopy, optical communication, quantum optics application, etc. Therefore mode-locked (ML) fiber lasers have been extensively investigated over the last decade due the number of scientific, medical and industrial applications. It should be noted, that USP fiber lasers can be treated as an ideal platform to expand future applications due to the complex ML nonlinear dynamics in a laser resonator. Up to now a series of novel ML regimes have been investigated e.g. self-similar pulses, noise-like pulses, multi-bound solitons and soliton rain generation. Recently, we have used a highly nonlinear germanosilicate fiber (with germanium oxides concentration in the core 50 mol. %) inside the resonator for more reliable and robust launching of passive mode-locking based on the nonlinear polarization evolution effect in fibers. In this work we have measured promising and stable ML regimes such as stretched pulses, soliton rain and multi-bound solitons formed in a highly-nonlinear ring laser and obtained by intracavity group velocity dispersion (GVD) variation in slightly negative region. As a result, we have obtained the low noise ultrashort pulse generation with duration 59 dB) and relative intensity noise <-101 dBc / Hz.

  13. Geometrically nonlinear resonance of higher-order shear deformable functionally graded carbon-nanotube-reinforced composite annular sector plates excited by harmonic transverse loading

    Science.gov (United States)

    Gholami, Raheb; Ansari, Reza

    2018-02-01

    This article presents an attempt to study the nonlinear resonance of functionally graded carbon-nanotube-reinforced composite (FG-CNTRC) annular sector plates excited by a uniformly distributed harmonic transverse load. To this purpose, first, the extended rule of mixture including the efficiency parameters is employed to approximately obtain the effective material properties of FG-CNTRC annular sector plates. Then, the focus is on presenting the weak form of discretized mathematical formulation of governing equations based on the variational differential quadrature (VDQ) method and Hamilton's principle. The geometric nonlinearity and shear deformation effects are considered based on the von Kármán assumptions and Reddy's third-order shear deformation plate theory, respectively. The discretization process is performed via the generalized differential quadrature (GDQ) method together with numerical differential and integral operators. Then, an efficient multi-step numerical scheme is used to obtain the nonlinear dynamic behavior of the FG-CNTRC annular sector plates near their primary resonance as the frequency-response curve. The accuracy of the present results is first verified and then a parametric study is presented to show the impacts of CNT volume fraction, CNT distribution pattern, geometry of annular sector plate and sector angle on the nonlinear frequency-response curve of FG-CNTRC annular sector plates with different edge supports.

  14. Influence of Fano interference and incoherent processes on optical bistability in a four-level quantum dot nanostructure

    International Nuclear Information System (INIS)

    Hossein Asadpour, Seyyed; Solookinejad, G; Panahi, M; Ahmadi Sangachin, E

    2016-01-01

    Role of Fano interference and incoherent pumping field on optical bistability in a four-level designed InGaN/GaN quantum dot nanostructure embedded in a unidirectional ring cavity are analyzed. It is found that intensity threshold of optical bistability can be manipulated by Fano interference. It is shown that incoherent pumping fields make the threshold of optical bistability behave differently by Fano interference. Moreover, in the presence of Fano interference the medium becomes phase-dependent. Therefore, the relative phase of applied fields can affect the behaviors of optical bistability and intensity threshold can be controlled easily. (paper)

  15. Crossing a Nonlinear Resonance

    Indian Academy of Sciences (India)

    IAS Admin

    Fermi's theory for the acceleration of cosmic rays [2] as- sumes that the ... The most well-known example goes back to the Lorentz–. Einstein .... inside and reflecting from the boundary according to ..... Here the chaotic layers of different.

  16. Fano factors of rare gases and their mixtures

    International Nuclear Information System (INIS)

    Lima, E.P. de; Salete, M.; Leite, S.C.P.; Alves, M.A.F.; Policarpo, A.J.P.

    1982-01-01

    Measurements of FW (Fano factor x mean energy to make an ion-pair) for several non metastable Penning gas mixtures were made using the proportional scintillation process. Taking for W the values that correspond to 5.3 MeV alpha particles, upper limits of F were determined. The following results were obtained: 100% Xe, FW = 3.247, F <= 0.15 +- 0.03; 100% Ar, FW = 10.536, F <= 0.40 +- 0.03; Ar + 80% Xe, FW = 4.635, F <= 0.21 +- 0.03; Ar + 5% Kr, FW = 9.397, F <= 0.37 +- 0.06; Ar + 24% Xe, FW = 5.093, F <= 0.23 +- 0.02; Ar + 20% Kr, FW = 3.038, F <= 0.12 +- 0.03; Ar + 20% Xe, FW = 3.582, F <= 0.16 +- 0.02; Ar + 79% Kr, FW = 3.113, F <= 0.13 +- 0.02; Ar + 5% Xe, FW = 3.204, F <= 0.14 +- 0.03; 100% Kr, FW = 4.584, F <= 0.19 +- 0.02. (orig.)

  17. Cores, Joins and the Fano-Flow Conjectures

    Directory of Open Access Journals (Sweden)

    Jin Ligang

    2018-02-01

    Full Text Available The Fan-Raspaud Conjecture states that every bridgeless cubic graph has three 1-factors with empty intersection. A weaker one than this conjecture is that every bridgeless cubic graph has two 1-factors and one join with empty intersection. Both of these two conjectures can be related to conjectures on Fano-flows. In this paper, we show that these two conjectures are equivalent to some statements on cores and weak cores of a bridgeless cubic graph. In particular, we prove that the Fan-Raspaud Conjecture is equivalent to a conjecture proposed in [E. Steffen, 1-factor and cycle covers of cubic graphs, J. Graph Theory 78 (2015 195–206]. Furthermore, we disprove a conjecture proposed in [G. Mazzuoccolo, New conjectures on perfect matchings in cubic graphs, Electron. Notes Discrete Math. 40 (2013 235–238] and we propose a new version of it under a stronger connectivity assumption. The weak oddness of a cubic graph G is the minimum number of odd components (i.e., with an odd number of vertices in the complement of a join of G. We obtain an upper bound of weak oddness in terms of weak cores, and thus an upper bound of oddness in terms of cores as a by-product.

  18. 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...

  19. Fano Effect and Quantum Entanglement in Hybrid Semiconductor Quantum Dot-Metal Nanoparticle System.

    Science.gov (United States)

    He, Yong; Zhu, Ka-Di

    2017-06-20

    In this paper, we review the investigation for the light-matter interaction between surface plasmon field in metal nanoparticle (MNP) and the excitons in semiconductor quantum dots (SQDs) in hybrid SQD-MNP system under the full quantum description. The exciton-plasmon interaction gives rise to the modified decay rate and the exciton energy shift which are related to the exciton energy by using a quantum transformation method. We illustrate the responses of the hybrid SQD-MNP system to external field, and reveal Fano effect shown in the absorption spectrum. We demonstrate quantum entanglement between two SQD mediated by surface plasmon field. In the absence of a laser field, concurrence of quantum entanglement will disappear after a few ns. If the laser field is present, the steady states appear, so that quantum entanglement produced will reach a steady-state entanglement. Because one of all optical pathways to induce Fano effect refers to the generation of quantum entangled states, It is shown that the concurrence of quantum entanglement can be obtained by observation for Fano effect. In a hybrid system including two MNP and a SQD, because the two Fano quantum interference processes share a segment of all optical pathways, there is correlation between the Fano effects of the two MNP. The investigations for the light-matter interaction in hybrid SQD-MNP system can pave the way for the development of the optical processing devices and quantum information based on the exciton-plasmon interaction.

  20. Fano Effect and Quantum Entanglement in Hybrid Semiconductor Quantum Dot-Metal Nanoparticle System

    Directory of Open Access Journals (Sweden)

    Yong He

    2017-06-01

    Full Text Available In this paper, we review the investigation for the light-matter interaction between surface plasmon field in metal nanoparticle (MNP and the excitons in semiconductor quantum dots (SQDs in hybrid SQD-MNP system under the full quantum description. The exciton-plasmon interaction gives rise to the modified decay rate and the exciton energy shift which are related to the exciton energy by using a quantum transformation method. We illustrate the responses of the hybrid SQD-MNP system to external field, and reveal Fano effect shown in the absorption spectrum. We demonstrate quantum entanglement between two SQD mediated by surface plasmon field. In the absence of a laser field, concurrence of quantum entanglement will disappear after a few ns. If the laser field is present, the steady states appear, so that quantum entanglement produced will reach a steady-state entanglement. Because one of all optical pathways to induce Fano effect refers to the generation of quantum entangled states, It is shown that the concurrence of quantum entanglement can be obtained by observation for Fano effect. In a hybrid system including two MNP and a SQD, because the two Fano quantum interference processes share a segment of all optical pathways, there is correlation between the Fano effects of the two MNP. The investigations for the light-matter interaction in hybrid SQD-MNP system can pave the way for the development of the optical processing devices and quantum information based on the exciton-plasmon interaction.

  1. Origin of optical non-linear response in TiN owing to excitation dynamics of surface plasmon resonance electronic oscillations

    Science.gov (United States)

    Divya, S.; Nampoori, V. P. N.; Radhakrishnan, P.; Mujeeb, A.

    2014-08-01

    TiN nanoparticles of average size 55 nm were investigated for their optical non-linear properties. During the experiment the irradiated laser wavelength coincided with the surface plasmon resonance (SPR) peak of the nanoparticle. The large non-linearity of the nanoparticle was attributed to the plasmon resonance, which largely enhanced the local field within the nanoparticle. Both open and closed aperture Z-scan experiments were performed and the corresponding optical constants were explored. The post-excitation absorption spectra revealed the interesting phenomenon of photo fragmentation leading to the blue shift in band gap and red shift in the SPR. The results are discussed in terms of enhanced interparticle interaction simultaneous with size reduction. Here, the optical constants being intrinsic constants for a particular sample change unusually with laser power intensity. The dependence of χ(3) is discussed in terms of the size variation caused by photo fragmentation. The studies proved that the TiN nanoparticles are potential candidates in photonics technology offering huge scope to study unexplored research for various expedient applications.

  2. Nonlinearity, Viscosity and Air-Compressibility Effects on the Helmholtz Resonant Wave Motion Generated by an Oscillating Twin Body in a Free Surface

    Science.gov (United States)

    Ananthakrishnan, Palaniswamy

    2012-11-01

    The problem is of practical relevance in determining the motion response of multi-hull and air-cushion vehicles in high seas and in littoral waters. The linear inviscid problem without surface pressure has been well studied in the past. In the present work, the nonlinear wave-body interaction problem is solved using finite-difference methods based on boundary-fitted coordinates. The inviscid nonlinear problem is tackled using the mixed Eulerian-Lagrangian formulation and the solution of the incompressible Navier-Stokes equations governing the viscous problem using a fractional-step method. The pressure variation in the air cushion is modeled using the isentropic gas equation pVγ = Constant. Results show that viscosity and free-surface nonlinearity significantly affect the hydrodynamic force and the wave motion at the resonant Helmholtz frequency (at which the primary wave motion is the vertical oscillation of the mean surface in between the bodies). Air compressibility suppresses the Helmholtz oscillation and enhances the wave radiation. Work supported by the ONR under the grant N00014-98-1-0151.

  3. Nonlinear response of a forced van der Pol-Duffing oscillator at non-resonant bifurcations of codimension two

    International Nuclear Information System (INIS)

    Ji, J.C.; Zhang, N.

    2009-01-01

    Non-resonant bifurcations of codimension two may appear in the controlled van der Pol-Duffing oscillator when two critical time delays corresponding to a double Hopf bifurcation have the same value. With the aid of centre manifold theorem and the method of multiple scales, the non-resonant response and two types of primary resonances of the forced van der Pol-Duffing oscillator at non-resonant bifurcations of codimension two are investigated by studying the possible solutions and their stability of the four-dimensional ordinary differential equations on the centre manifold. It is shown that the non-resonant response of the forced oscillator may exhibit quasi-periodic motions on a two- or three-dimensional (2D or 3D) torus. The primary resonant responses admit single and mixed solutions and may exhibit periodic motions or quasi-periodic motions on a 2D torus. Illustrative examples are presented to interpret the dynamics of the controlled system in terms of two dummy unfolding parameters and exemplify the periodic and quasi-periodic motions. The analytical predictions are found to be in good agreement with the results of numerical integration of the original delay differential equation.

  4. The Role of Nonlinearity in Computing Graph-Theoretical Properties of Resting-State Functional Magnetic Resonance Imaging Brain Networks

    Czech Academy of Sciences Publication Activity Database

    Hartman, David; Hlinka, Jaroslav; Paluš, Milan; Mantini, D.; Corbetta, M.

    2011-01-01

    Roč. 21, č. 1 (2011), art.no 013119 ISSN 1054-1500 R&D Projects: GA MŠk 7E08027 Institutional research plan: CEZ:AV0Z10300504 Keywords : complex network * fMRI * brain connectivity * nonlinear * mutual information * correlation Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 2.076, year: 2011

  5. All-Optical Switching Improvement Using Photonic-Crystal Fano Structures

    DEFF Research Database (Denmark)

    Yu, Yi; Xue, Weiqi; Hu, Hao

    2016-01-01

    by incorporating a partially transmitting element in the waveguide. Compared to traditional Lorentzian structures, the Fano structure shows improved switching contrast and speed without adding any extra phase modulation, corresponding to a much lower chirp parameter. Using a simple and ultracompact InP photonic...

  6. The basics of experimental determination of the Fano factor in intrinsic semiconductors

    International Nuclear Information System (INIS)

    Samedov, Victor-V.

    2013-06-01

    Intrinsic semiconductors such as High Purity Germanium Detectors are exceptional X-ray and gamma-ray detectors because of their large sizes and small band gap. They are used for fundamental scientific researches, nuclear material safeguards and security, environmental protection, and human health and safety. The fundamental limit of the energy resolution of a semiconductor detector is determined by variance in the number of electron-hole pairs produced by X-rays in detector volume. The principal characteristic of material for using as semiconductor detector is the Fano factor that determines the fluctuation in the number of electron-hole pairs. Now, all existing methods of experimental determination of the Fano factor in semiconductors are based on the subtraction of electronic noise from the signal variance. In this work, I propose the method of experimental determination of the Fano factor in a planar semiconductor detector based on dependences of the mean amplitude and the energy resolution on the electric field. It was shown that inverse electric field expansion of these dependences allow determining the Fano factor, electron mobility lifetime product, and relative variance of electron lifetime due to inhomogeneous charge transport in semiconductor material. The important advantage of the proposed method is independence on detector electronic noise. (authors)

  7. Resonantly scattering crystals and surfaces

    International Nuclear Information System (INIS)

    Gunn, J.M.F.; Mahon, P.J.

    1990-12-01

    We examine coherence effects from forming a crystal of resonant scatterers by generalising the Fano model for autoionising resonances in electron scattering from atoms to a lattice of such scatterers. (We have in mind the case of neutron scattering from nuclei.) We solve this problem to yield two branches to the dispersion relation for the neutron in general and three when the resonance coincides with a Brillouin Zone boundary. The 'width' of the resonance is enhanced over the isolated nucleus, the best candidate for observation being the 2eV 185 Re resonance near the Bragg condition. We use these results to calculate the reflection coefficient from a surface, revealing total external reflection near resonance. We discuss experimental feasibility in both the neutron and electron cases. (author)

  8. Analysis of the quasiperiodic response of a generalized van der Pol nonlinear system in the resonance zone

    Czech Academy of Sciences Publication Activity Database

    Náprstek, Jiří; Fischer, Cyril

    -, - (2018), , , --- ISSN 0045-7949 R&D Projects: GA ČR(CZ) GA15-01035S Institutional support: RVO:68378297 Keywords : nonlinear dynamics * generalized van der Pol system * quasiperiodic response * synchronization effects * stability of auto-oscillation Subject RIV: JM - Building Engineering OBOR OECD: Mechanical engineering Impact factor: 2.847, year: 2016 http://www.sciencedirect.com/science/article/pii/S004579491730278X

  9. Distortion of He(2l2l`) Fano lineshapes by strong post-collision interaction in H{sup +}-He collisions

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Benhenni, M.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Toulouse-3 Univ., 31 (France)

    1996-05-28

    The three-body post-collisional interaction (PCI) between the scattered proton, recoil target ion and emitted electron has been investigated by electron spectrometry near the 2l2l` helium resonances, in the 20-100 keV energy range (V{sub p} 0.9-2 au). Particular attention has been paid to the PCI deformations of the Fano lineshapes when V-vector``{sub p} {approx_equal} V-vector {sub e}(2l2l`). Their angle and collision velocity dependences have been studied for the first time experimentally. A large variety of lineshapes have been observed, all of them successfully described by a single formula. At the lowest proton velocities the rescattering effect (also called Coulomb two-path scattering) is seen. (Author).

  10. Q-factorial Gorenstein toric Fano varieties with large Picard number

    DEFF Research Database (Denmark)

    Nill, Benjamin; Øbro, Mikkel

    2010-01-01

    In dimension $d$, ${\\boldsymbol Q}$-factorial Gorenstein toric Fano varieties with Picard number $\\rho_X$ correspond to simplicial reflexive polytopes with $\\rho_X + d$ vertices. Casagrande showed that any $d$-dimensional simplicial reflexive polytope has at most $3 d$ and $3d-1$ vertices if $d......$ is even and odd, respectively. Moreover, for $d$ even there is up to unimodular equivalence only one such polytope with $3 d$ vertices, corresponding to the product of $d/2$ copies of a del Pezzo surface of degree six. In this paper we completely classify all $d$-dimensional simplicial reflexive polytopes...... having $3d-1$ vertices, corresponding to $d$-dimensional ${\\boldsymbol Q}$-factorial Gorenstein toric Fano varieties with Picard number $2d-1$. For $d$ even, there exist three such varieties, with two being singular, while for $d > 1$ odd there exist precisely two, both being nonsingular toric fiber...

  11. Tailoring double Fano profiles with plasmon-assisted quantum interference in hybrid exciton-plasmon system

    International Nuclear Information System (INIS)

    Zhao, Dongxing; Wu, Jiarui; Gu, Ying; Gong, Qihuang

    2014-01-01

    We propose tailoring of the double Fano profiles via plasmon-assisted quantum interference in a hybrid exciton-plasmon system. Tailoring is performed by the interference between two exciton channels interacting with a common localized surface plasmon. Using an applied field of low intensity, the absorption spectrum of the hybrid system reveals a double Fano lineshape with four peaks. For relatively large field intensity, a broad flat window in the absorption spectrum appears which results from the destructive interference between excitons. Because of strong constructive interference, this window vanishes as intensity is further increased. We have designed a nanometer bandpass optical filter for visible light based on tailoring of the optical spectrum. This study provides a platform for quantum interference that may have potential applications in ultracompact tunable quantum devices.

  12. Terahertz sensing of highly absorptive water-methanol mixtures with multiple resonances in metamaterials.

    Science.gov (United States)

    Chen, Min; Singh, Leena; Xu, Ningning; Singh, Ranjan; Zhang, Weili; Xie, Lijuan

    2017-06-26

    Terahertz sensing of highly absorptive aqueous solutions remains challenging due to strong absorption of water in the terahertz regime. Here, we experimentally demonstrate a cost-effective metamaterial-based sensor integrated with terahertz time-domain spectroscopy for highly absorptive water-methanol mixture sensing. This metamaterial has simple asymmetric wire structures that support multiple resonances including a fundamental Fano resonance and higher order dipolar resonance in the terahertz regime. Both the resonance modes have strong intensity in the transmission spectra which we exploit for detection of the highly absorptive water-methanol mixtures. The experimentally characterized sensitivities of the Fano and dipole resonances for the water-methanol mixtures are found to be 160 and 305 GHz/RIU, respectively. This method provides a robust route for metamaterial-assisted terahertz sensing of highly absorptive chemical and biochemical materials with multiple resonances and high accuracy.

  13. Multiple Fano resonances in single-layer nonconcentric core-shell nanostructures

    DEFF Research Database (Denmark)

    Zhang, Jingjing; Zayats, Anatoly

    2013-01-01

    where the multiple dark modes appear due to the geometrical symmetry breaking induced by axial offset of the core. Both dielectric-core-metal-shell (DCMS) and metal-core-dielectric-shell (MCDS) configurations have been studied. Compared to the MCDS structure, the DCMS configuration provides higher...

  14. Magnetic forces and localized resonances in electron transfer through quantum rings.

    Science.gov (United States)

    Poniedziałek, M R; Szafran, B

    2010-11-24

    We study the current flow through semiconductor quantum rings. In high magnetic fields the current is usually injected into the arm of the ring preferred by classical magnetic forces. However, for narrow magnetic field intervals that appear periodically on the magnetic field scale the current is injected into the other arm of the ring. We indicate that the appearance of the anomalous-non-classical-current circulation results from Fano interference involving localized resonant states. The identification of the Fano interference is based on the comparison of the solution of the scattering problem with the results of the stabilization method. The latter employs the bound-state type calculations and allows us to extract both the energy of metastable states localized within the ring and the width of resonances by analysis of the energy spectrum of a finite size system as a function of its length. The Fano resonances involving states of anomalous current circulation become extremely narrow on both the magnetic field and energy scales. This is consistent with the orientation of the Lorentz force that tends to keep the electron within the ring and thus increases the lifetime of the electron localization within the ring. Absence of periodic Fano resonances in electron transfer probability through a quantum ring containing an elastic scatterer is also explained.

  15. X-ray detected magnetic resonance of YIG thin films in the nonlinear regime of spin waves

    Energy Technology Data Exchange (ETDEWEB)

    Goulon, J., E-mail: goulon@esrf.f [European Synchrotron Radiation Facility (ESRF), B.P. 220, F-38043 Grenoble Cedex (France); Rogalev, A.; Wilhelm, F.; Goujon, G. [European Synchrotron Radiation Facility (ESRF), B.P. 220, F-38043 Grenoble Cedex (France); Brouder, Ch. [Institut de Mineralogie et de Physique des Milieux Condenses, UMR-CNRS 7590, Universite Paris VI-VII, 4 place Jussieu, F-75252 Paris Cedex 05 (France); Yaresko, A. [Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart (Germany); Ben Youssef, J.; Indenbom, M.V. [Laboratoire de Magnetisme de Bretagne, CNRS FRE 2697, UFR Sciences et Techniques, F-29328 Brest Cedex (France)

    2010-08-15

    We discuss the information content of element/edge resolved X-ray detected magnetic resonance (XDMR) experiments carried out on yttrium iron garnet (YIG) thin films. Starting with a phenomenological approach, it is shown that the photoionisation of deep atomic core levels by circularly polarized X-rays can be used to probe the precession dynamics of spin or orbital magnetization components in empty final states of proper symmetry. Crude estimates of the opening angle of the uniform precession mode were tentatively deduced from the ratio of the XDMR and XMCD absorption cross-sections either at the iron or yttrium absorbing sites. The implications of the most recent experimental results collected at the ESRF are analyzed, keeping in mind that: (i) the Fe K-edge XDMR signal is largely dominated by the precession of orbital magnetization components at the tetrahedral iron sites; (ii) the Y L-edges XDMR signal essentially describes the precession of induced spin magnetization involving the 4d states of yttrium. In the magnetostatic regime, we produce clear experimental evidence of collective excitations of orbital magnetization waves, especially under high pumping power. Several coupling mechanisms could explain our observations, starting with pseudo-dipolar interactions in ferromagnetic systems. In ferrimagnetic systems in which orbital degeneracy and orbital ordering make the excitation of orbitons possible, one may envisage additional modes of excitation or relaxation of orbital magnetization waves. This interpretation looks fully consistent with the results of band structure calculations carried out recently on YIG with fully relativistic LMTO-LSDA methods.

  16. 110 GHz hybrid mode-locked fiber laser with enhanced extinction ratio based on nonlinear silicon-on-insulator micro-ring-resonator (SOI MRR)

    International Nuclear Information System (INIS)

    Liu, Yang; Hsu, Yung; Chow, Chi-Wai; Yang, Ling-Gang; Lai, Yin-Chieh; Yeh, Chien-Hung; Tsang, Hon-Ki

    2016-01-01

    We propose and experimentally demonstrate a new 110 GHz high-repetition-rate hybrid mode-locked fiber laser using a silicon-on-insulator microring-resonator (SOI MRR) acting as the optical nonlinear element and optical comb filter simultaneously. By incorporating a phase modulator (PM) that is electrically driven at a fraction of the harmonic frequency, an enhanced extinction ratio (ER) of the optical pulses can be produced. The ER of the optical pulse train increases from 3 dB to 10 dB. As the PM is only electrically driven by the signal at a fraction of the harmonic frequency, in this case 22 GHz (110 GHz/5 GHz), a low bandwidth PM and driving circuit can be used. The mode-locked pulse width and the 3 dB spectral bandwidth of the proposed mode-locked fiber laser are measured, showing that the optical pulses are nearly transform limited. Moreover, stability evaluation for an hour is performed, showing that the proposed laser can achieve stable mode-locking without the need for optical feedback or any other stabilization mechanism. (letter)

  17. On the fundamentals of winning virtuous strategies creation toward leveraged buyout transactions implementation during private equity investment in conditions of resonant absorption of discrete information in diffusion - type financial system with induced nonlinearities

    OpenAIRE

    Ledenyov, Dimitri O.; Ledenyov, Viktor O.

    2014-01-01

    The authors perform an original research on the fundamentals of winning virtuous strategies creation toward the leveraged buyout transactions implementation during the private equity investment in the conditions of the resonant absorption of discrete information in the diffusion - type financial system with the induced nonlinearities at the influences by the Schumpeterian creative disruption processes in the free market economy. We propose that the money is a financial computing process, whic...

  18. Nonlinear dynamics aspects of particle accelerators

    International Nuclear Information System (INIS)

    Araki, H.; Ehlers, J.; Hepp, K.; Kippenhahn, R.; Weidenmuller, A.; Zittartz, J.

    1986-01-01

    This book contains 18 selections. Some of the titles are: Integrable and Nonintegrable Hamiltonian Systems; Nonlinear Dynamics Aspects of Modern Storage Rings; Nonlinear Beam-Beam Resonances; Synchro-Betatron Resonances; Review of Beam-Beam Simulations; and Perturbation Method in Nonlinear Dynamics

  19. Linear and ultrafast nonlinear plasmonics of single nano-objects

    Science.gov (United States)

    Crut, Aurélien; Maioli, Paolo; Vallée, Fabrice; Del Fatti, Natalia

    2017-03-01

    Single-particle optical investigations have greatly improved our understanding of the fundamental properties of nano-objects, avoiding the spurious inhomogeneous effects that affect ensemble experiments. Correlation with high-resolution imaging techniques providing morphological information (e.g. electron microscopy) allows a quantitative interpretation of the optical measurements by means of analytical models and numerical simulations. In this topical review, we first briefly recall the principles underlying some of the most commonly used single-particle optical techniques: near-field, dark-field, spatial modulation and photothermal microscopies/spectroscopies. We then focus on the quantitative investigation of the surface plasmon resonance (SPR) of metallic nano-objects using linear and ultrafast optical techniques. While measured SPR positions and spectral areas are found in good agreement with predictions based on Maxwell’s equations, SPR widths are strongly influenced by quantum confinement (or, from a classical standpoint, surface-induced electron scattering) and, for small nano-objects, cannot be reproduced using the dielectric functions of bulk materials. Linear measurements on single nano-objects (silver nanospheres and gold nanorods) allow a quantification of the size and geometry dependences of these effects in confined metals. Addressing the ultrafast response of an individual nano-object is also a powerful tool to elucidate the physical mechanisms at the origin of their optical nonlinearities, and their electronic, vibrational and thermal relaxation processes. Experimental investigations of the dynamical response of gold nanorods are shown to be quantitatively modeled in terms of modifications of the metal dielectric function enhanced by plasmonic effects. Ultrafast spectroscopy can also be exploited to unveil hidden physical properties of more complex nanosystems. In this context, two-color femtosecond pump-probe experiments performed on individual

  20. Limpieza y esterilización en quirófano de oftalomología

    OpenAIRE

    Lama Ochoa de Retama, María Angosto

    2012-01-01

    En oftalmología el espacio para la cirugía, debe cumplir unos requerim ientos, debe ser una zona de acceso limitado y se deben respetar las normas de asepsia quirúrgica.. Se deben de tener en cuenta conceptos como asepsia, asepsia quirúrgica, limpieza y desinfección. Hay que tener muy en cuenta la limpieza y desinfección de superficies. El personal debe tener y respetar unas normas dentro del quirófano sobre cómo llevar el pijama, gorro, guantes, mascarilla...Se debe de tener en cuenta la lim...

  1. Shot noise and Fano factor in tunneling in three-band pseudospin-1 Dirac-Weyl systems

    Science.gov (United States)

    Zhu, Rui; Hui, Pak Ming

    2017-06-01

    Tunneling through a potential barrier of height V0 in a two-dimensional system with a band structure consisting of three bands with a flat band intersecting the touching apices of two Dirac cones is studied. Results of the transmission coefficient at various incident angles, conductivity, shot noise, and Fano factor in this pseudospin-1 Dirac-Weyl system are presented and contrasted with those in graphene which is typical of a pseudospin-1/2 system. The pseudospin-1 system is found to show a higher transmission and suppressed shot noise in general. Significant differences in the shot noise and Fano factor due to the super Klein tunneling effect that allows perfect transmission at all incident angles under certain conditions are illustrated. For Fermi energy EF =V0 / 2, super Klein tunneling leads to a noiseless conductivity that takes on the maximum value 2e2 DkF / (πh) for 0 ≤EF ≤V0. This gives rise to a minimum Fano factor, in sharp contrast with that of a local maximum in graphene. For EF =V0, the band structure of pseudospin-1 system no longer leads to a quantized value of the conductivity as in graphene. Both the conductivity and the shot noise show a minimum with the Fano factor approaching 1/4, which is different from the value of 1/3 in graphene.

  2. Guided mode resonance in planar metamaterials consisting of two ring resonators with different sizes

    International Nuclear Information System (INIS)

    Yu Zhen; Che Hang; Liu Jianjun; Jing Xufeng; Li Xiangjun; Hong Zhi

    2017-01-01

    We proposed and experimentally investigated a two-ring-resonator composed planar hybrid metamaterial (MM), in which the spectra of guided mode resonance (GMR) and Fano resonance or EIT-like response induced by coherent interaction between MM resonance and GMR can be easily controlled by the size of the two rings in the terahertz regime. Furthermore, a four-ring-resonator composed MM for polarization-insensitive GMRs was demonstrated, where GMRs of both TE and TM modes are physically attributed to the diffraction coupling by two ±45° tilting gratings. Such kind of device has great potential in ultra-sensitive label-free sensors, filters, or slow light based devices. (paper)

  3. High efficiency all-optical plasmonic diode based on a nonlinear side-coupled waveguide-cavity structure with broken symmetry

    Science.gov (United States)

    Liang, Hong-Qin; Liu, Bin; Hu, Jin-Feng; He, Xing-Dao

    2018-05-01

    An all-optical plasmonic diode, comprising a metal-insulator-metal waveguide coupled with a stub cavity, is proposed based on a nonlinear Fano structure. The key technique used is to break structural spatial symmetry by a simple reflector layer in the waveguide. The spatial asymmetry of the structure gives rise to the nonreciprocity of coupling efficiencies between the Fano cavity and waveguides on both sides of the reflector layer, leading to a nonreciprocal nonlinear response. Transmission properties and dynamic responses are numerically simulated and investigated by the nonlinear finite-difference time-domain method. In the proposed structure, high-efficiency nonreciprocal transmission can be achieved with a low power threshold and an ultrafast response time (subpicosecond level). A high maximum transmittance of 89.3% and an ultra-high transmission contrast ratio of 99.6% can also be obtained. The device can be flexibly adjusted for working wavebands by altering the stub cavity length.

  4. Fano and Dicke effects in a double Rashba-ring system

    International Nuclear Information System (INIS)

    Apel, V M; Orellana, P A; Pacheco, M

    2008-01-01

    The electronic transport in a system of two quantum rings side-coupled to a quantum wire is studied via a single-band tunneling tight-binding Hamiltonian. We derived analytical expressions for the conductance and spin polarization when the rings are threaded by magnetic fluxes with Rashba spin-orbit interaction. We show that by using the Fano and Dicke effects this system can be used as an efficient spin filter even for small spin-orbit interaction and small values of magnetic fluxes. We compare the spin-dependent polarization of this design and the polarization obtained with one ring side-coupled to a quantum ring. As a main result, we find better spin polarization capabilities as compared to the one-ring design

  5. Restauración de la Iglesia de San Francesco en Fano (Italia

    Directory of Open Access Journals (Sweden)

    Claudio Galli

    2014-07-01

    Full Text Available La iglesia de San Francisco de Fano expuesta a cielo abierto desde hace décadas posee una gran capacidad de evocación para propios y extraños. La intervención llevada a cabo ha asumido su condición incompleta y fragmentaria evitando una repristinación que era relativamente fácil por la existencia de abundante documentación y restos conservados. La restauración ha acometido la tarea de afianzar sus fábricas desplomadas, consolidar la decoración remanente e insertar las instalaciones estrictamente necesarias para el mantenimiento del césped natural como pavimento y la iluminación del espacio para su uso como foro de actos públicos o, simplemente, como museo de los avatares de su propia historia construida.

  6. Fano Description of Single-Hydrocarbon Fluorescence Excited by a Scanning Tunneling Microscope.

    Science.gov (United States)

    Kröger, Jörg; Doppagne, Benjamin; Scheurer, Fabrice; Schull, Guillaume

    2018-06-13

    The detection of fluorescence with submolecular resolution enables the exploration of spatially varying photon yields and vibronic properties at the single-molecule level. By placing individual polycyclic aromatic hydrocarbon molecules into the plasmon cavity formed by the tip of a scanning tunneling microscope and a NaCl-covered Ag(111) surface, molecular light emission spectra are obtained that unravel vibrational progression. In addition, light spectra unveil a signature of the molecule even when the tunneling current is injected well separated from the molecular emitter. This signature exhibits a distance-dependent Fano profile that reflects the subtle interplay between inelastic tunneling electrons, the molecular exciton and localized plasmons in at-distance as well as on-molecule fluorescence. The presented findings open the path to luminescence of a different class of molecules than investigated before and contribute to the understanding of single-molecule luminescence at surfaces in a unified picture.

  7. Nonlinear Response of Strong Nonlinear System Arisen in Polymer Cushion

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2013-01-01

    Full Text Available A dynamic model is proposed for a polymer foam-based nonlinear cushioning system. An accurate analytical solution for the nonlinear free vibration of the system is derived by applying He's variational iteration method, and conditions for resonance are obtained, which should be avoided in the cushioning design.

  8. Fully Valley/spin polarized current and Fano factor through the Graphene/ferromagnetic silicene/Graphene junction

    Energy Technology Data Exchange (ETDEWEB)

    Rashidian, Zeinab; Rezaeipour, Saeid [Department of Physics, Faculty of Science, Lorestan University, Lorestan (Iran, Islamic Republic of); Hajati, Yaser [Department of Physics, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz (Iran, Islamic Republic of); Lorestaniweiss, Zeinab, E-mail: rashidian1983z@gmail.com [Department of Physics, Faculty of Science, Lorestan University, Lorestan (Iran, Islamic Republic of); Ueda, Akiko [Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba (Japan)

    2017-02-15

    In this work, we study the transport properties of Dirac fermions through the ferromagnetic silicene which is sandwiched between the Graphene leads (G/FS/G). Spin/valley conductance, spin/valley polarization, and also Fano factor are theoretically calculated using the Landauer-Buttiker formula. We find that the fully valley and spin polarized currents through the G/FS/G junction can be obtained by increasing the electric field strength and the length of ferromagnetic silicene region. Moreover, the valley polarization can be tuned from negative to positive values by changing the electric field. We find that the Fano factor also changes with the spin and valley polarization. Our findings of high controllability of the spin and valley transport in such a G/FS/G junction the potential of this junction for spin-valleytronics applications.

  9. Tunable THz wave absorption by graphene-assisted plasmonic metasurfaces based on metallic split ring resonators

    International Nuclear Information System (INIS)

    Ahmadivand, Arash; Sinha, Raju; Karabiyik, Mustafa; Vabbina, Phani Kiran; Gerislioglu, Burak; Kaya, Serkan; Pala, Nezih

    2017-01-01

    Graphene plasmonics has been introduced as a novel platform to design various nano- and microstructures to function in a wide range of spectrum from optical to THz frequencies. Herein, we propose a tunable plasmonic metamaterial in the THz regime by using metallic (silver) concentric microscale split ring resonator arrays on a multilayer metasurface composed of silica and silicon layers. We obtained an absorption percentage of 47.9% including two strong Fano resonant dips in THz regime for the purely plasmonic metamaterial without graphene layer. Considering the data of an atomic graphene sheet (with the thickness of ~0.35 nm) in both analytical and experimental regimes obtained by prior works, we employed a graphene layer under concentric split ring resonator arrays and above the multilayer metasurface to enhance the absorption ratio in THz bandwidth. Our numerical and analytical results proved that the presence of a thin graphene layer enhances the absorption coefficient of MM to 64.35%, at the highest peak in absorption profile that corresponds to the Fano dip position. We also have shown that changing the intrinsic characteristics of graphene sheet leads to shifts in the position of Fano dips and variations in the absorption efficiency. The maximum percentage of absorption (~67%) was obtained for graphene-based MM with graphene layer with dissipative loss factor of 1477 Ω. Employing the antisymmetric feature of the split ring resonators, the proposed graphene-based metamaterial with strong polarization dependency is highly sensitive to the polarization angle of the incident THz beam.

  10. Averaging of nonlinearity-managed pulses

    International Nuclear Information System (INIS)

    Zharnitsky, Vadim; Pelinovsky, Dmitry

    2005-01-01

    We consider the nonlinear Schroedinger equation with the nonlinearity management which describes Bose-Einstein condensates under Feshbach resonance. By using an averaging theory, we derive the Hamiltonian averaged equation and compare it with other averaging methods developed for this problem. The averaged equation is used for analytical approximations of nonlinearity-managed solitons

  11. Experimental studies of nonlinear beam dynamics

    International Nuclear Information System (INIS)

    Caussyn, D.D.; Ball, M.; Brabson, B.; Collins, J.; Curtis, S.A.; Derenchuck, V.; DuPlantis, D.; East, G.; Ellison, M.; Ellison, T.; Friesel, D.; Hamilton, B.; Jones, W.P.; Lamble, W.; Lee, S.Y.; Li, D.; Minty, M.G.; Sloan, T.; Xu, G.; Chao, A.W.; Ng, K.Y.; Tepikian, S.

    1992-01-01

    The nonlinear beam dynamics of transverse betatron oscillations were studied experimentally at the Indiana University Cyclotron Facility cooler ring. Motion in one dimension was measured for betatron tunes near the third, fourth, fifth, and seventh integer resonances. This motion is described by coupling between the transverse modes of motion and nonlinear field errors. The Hamiltonian for nonlinear particle motion near the third- and fourth-integer-resonance conditions has been deduced

  12. Space charge in nanostructure resonances

    Science.gov (United States)

    Price, Peter J.

    1996-10-01

    In quantum ballistic propagation of electrons through a variety of nanostructures, resonance in the energy-dependent transmission and reflection probabilities generically is associated with (1) a quasi-level with a decay lifetime, and (2) a bulge in electron density within the structure. It can be shown that, to a good approximation, a simple formula in all cases connects the density of states for the latter to the energy dependence of the phase angles of the eigen values of the S-matrix governing the propagation. For both the Lorentzian resonances (normal or inverted) and for the Fano-type resonances, as a consequence of this eigen value formula, the space charge due to filled states over the energy range of a resonance is just equal (for each spin state) to one electron charge. The Coulomb interaction within this space charge is known to 'distort' the electrical characteristics of resonant nanostructures. In these systems, however, the exchange effect should effectively cancel the interaction between states with parallel spins, leaving only the anti-parallel spin contribution.

  13. Tunable multipole resonances in plasmonic crystals made by four-beam holographic lithography

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y.; Li, X.; Zhang, X.; Prybolsky, S.; Shepard, G. D.; Strauf, S., E-mail: Strauf@stevens.edu [Department of Physics and Engineering Physics, Stevens Institute of Technology, Castle Point on the Hudson, Hoboken, New Jersey 07030 (United States)

    2016-02-01

    Plasmonic nanostructures confine light to sub-wavelength scales, resulting in drastically enhanced light-matter interactions. Recent interest has focused on controlled symmetry breaking to create higher-order multipole plasmonic modes that store electromagnetic energy more efficiently than dipole modes. Here we demonstrate that four-beam holographic lithography enables fabrication of large-area plasmonic crystals with near-field coupled plasmons as well as deliberately broken symmetry to sustain multipole modes and Fano-resonances. Compared with the spectrally broad dipole modes we demonstrate an order of magnitude improved Q-factors (Q = 21) when the quadrupole mode is activated. We further demonstrate continuous tuning of the Fano-resonances using the polarization state of the incident light beam. The demonstrated technique opens possibilities to extend the rich physics of multipole plasmonic modes to wafer-scale applications that demand low-cost and high-throughput.

  14. Shot noise and electronic properties in the inversion-symmetric Weyl semimetal resonant structure

    Science.gov (United States)

    Yang, Yanling; Bai, Chunxu; Xu, Xiaoguang; Jiang, Yong

    2018-02-01

    Using the transfer matrix method, the authors combine the analytical formula with numerical calculation to explore the shot noise and conductance of massless Weyl fermions in the Weyl semimetal resonant junction. By varying the barrier strength, the structure of the junction, the Fermi energy, and the crystallographic angle, the shot noise and conductance can be tuned efficiently. For a quasiperiodic superlattice, in complete contrast to the conventional junction case, the effect of the disorder strength on the shot noise and conductance depends on the competition of classical tunneling and Klein tunneling. Moreover, the delta barrier structure is also vital in determining the shot noise and conductance. In particular, a universal Fano factor has been found in a single delta potential case, whereas the resonant structure of the Fano factor perfectly matches with the number of barriers in a delta potential superlattice. These results are crucial for engineering nanoelectronic devices based on this topological semimetal material.

  15. Controlling Parametric Resonance

    DEFF Research Database (Denmark)

    Galeazzi, Roberto; Pettersen, Kristin Ytterstad

    2012-01-01

    the authors review the conditions for the onset of parametric resonance, and propose a nonlinear control strategy in order to both induce the resonant oscillations and to stabilize the unstable motion. Lagrange’s theory is used to derive the dynamics of the system and input–output feedback linearization...

  16. Relativistic decay widths of autoionization processes: The relativistic FanoADC-Stieltjes method

    Energy Technology Data Exchange (ETDEWEB)

    Fasshauer, Elke, E-mail: Elke.Fasshauer@uit.no [Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø–The Arctic University of Norway, N-9037 Tromsø (Norway); Theoretische Chemie, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Kolorenč, Přemysl [Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, 180 00 Prague (Czech Republic); Pernpointner, Markus [Theoretische Chemie, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany)

    2015-04-14

    Electronic decay processes of ionized systems are, for example, the Auger decay or the Interatomic/ Intermolecular Coulombic Decay. In both processes, an energetically low lying vacancy is filled by an electron of an energetically higher lying orbital and a secondary electron is instantaneously emitted to the continuum. Whether or not such a process occurs depends both on the energetic accessibility and the corresponding lifetime compared to the lifetime of competing decay mechanisms. We present a realization of the non-relativistically established FanoADC-Stieltjes method for the description of autoionization decay widths including relativistic effects. This procedure, being based on the Algebraic Diagrammatic Construction (ADC), was adapted to the relativistic framework and implemented into the relativistic quantum chemistry program package Dirac. It is, in contrast to other existing relativistic atomic codes, not limited to the description of autoionization lifetimes in spherically symmetric systems, but is instead also applicable to molecules and clusters. We employ this method to the Auger processes following the Kr3d{sup −1}, Xe4d{sup −1}, and Rn5d{sup −1} ionization. Based on the results, we show a pronounced influence of mainly scalar-relativistic effects on the decay widths of autoionization processes.

  17. Dynamical Fano-Like Interference between Rabi Oscillations and Coherent Phonons in a Semiconductor Microcavity System.

    Science.gov (United States)

    Yoshino, S; Oohata, G; Mizoguchi, K

    2015-10-09

    We report on dynamical interference between short-lived Rabi oscillations and long-lived coherent phonons in CuCl semiconductor microcavities resulting from the coupling between the two oscillations. The Fourier-transformed spectra of the time-domain signals obtained from semiconductor microcavities by using a pump-probe technique show that the intensity of the coherent longitudinal optical phonon of CuCl is enhanced by increasing that of the Rabi oscillation, which indicates that the coherent phonon is driven by the Rabi oscillation through the Fröhlich interaction. Moreover, as the Rabi oscillation frequency decreases upon crossing the phonon frequency, the spectral profile of the coherent phonon changes from a peak to a dip with an asymmetric structure. The continuous wavelet transformation reveals that these peak and dip structures originate from constructive and destructive interference between Rabi oscillations and coherent phonons, respectively. We demonstrate that the asymmetric spectral structures in relation to the frequency detuning are well reproduced by using a classical coupled oscillator model on the basis of dynamical Fano-like interference.

  18. Mala praxis médica en el quirófano

    Directory of Open Access Journals (Sweden)

    Tania Amores Agulla

    Full Text Available La mala praxis médica constituye actualmente un problema global de salud, incluso en los mejores centros hospitalarios del mundo. Se consultaron 26 referencias bibliográficas nacionales e internacionales acerca del tema con el objetivo de determinar el estado actual de los errores médicos en el quirófano. El ejercicio de la medicina tiene riesgos inherentes y la naturaleza humana hace imposible que el hombre sea infalible. Los tipos de errores más frecuentes en la práctica médica son: administración equívoca de medicamentos, diagnósticos inciertos, fallas técnicas (procedimientos insuficientes, incompletos y/o incorrectos y demora en el salón de operaciones. Las causas más frecuentes engloban el cansancio, la prisa, falta de conocimientos, entre otras. La prevención es posible y son numerosas las estrategias aplicadas por los diferentes sistemas de salud: estimular el trabajo en equipo, fortalecer la capacitación del médico y personal paramédico, evitar confiar en la memoria usando listas de chequeo, estandarizar procedimientos y protocolos, crear la cultura del reporte voluntario de errores. El error debe ser utilizado como una oportunidad para aprender, para mejorar la calidad en la atención y por ende, la seguridad de los enfermos.

  19. Nonlinear waves in solar plasmas - a review

    International Nuclear Information System (INIS)

    Ballai, I

    2006-01-01

    Nonlinearity is a direct consequence of large scale dynamics in the solar plasmas. When nonlinear steepening of waves is balanced by dispersion, solitary waves are generated. In the vicinity of resonances, waves can steepen into nonlinear waves influencing the efficiency of energy deposition. Here we review recent theoretical breakthroughs that have lead to a greater understanding of many aspects of nonlinear waves arising in homogeneous and inhomogeneous solar plasmas

  20. Time-dependent resonant tunnelling for parallel-coupled double quantum dots

    International Nuclear Information System (INIS)

    Dong Bing; Djuric, Ivana; Cui, H L; Lei, X L

    2004-01-01

    We derive the quantum rate equations for an Aharonov-Bohm interferometer with two vertically coupled quantum dots embedded in each of two arms by means of the nonequilibrium Green function in the sequential tunnelling regime. Based on these equations, we investigate time-dependent resonant tunnelling under a small amplitude irradiation and find that the resonant photon-assisted tunnelling peaks in photocurrent demonstrate a combination behaviour of Fano and Lorentzian resonances due to the interference effect between the two pathways in this parallel configuration, which is controllable by threading the magnetic flux inside this device

  1. Mirroring behavior of partial photodetachment and photoionization cross sections in the neighborhood of a resonance

    International Nuclear Information System (INIS)

    Liu, C.; Starace, A.F.

    1999-01-01

    Partial photodetachment and photoionization cross sections corresponding to highly excited residual atoms or ions are shown analytically to mirror one another in the neighborhood of a resonance. More precisely, any two groupings of partial cross sections are shown here to have components whose variations with energy near a resonance are equal in magnitude and opposite in direction. This work extends an analysis of Starace [Phys. Rev. A 16, 231 (1977)] for the behavior of partial cross sections near a resonance to the case when the ρ 2 parameter of Fano and Cooper [Phys. Rev. 137, A1364 (1965)] tends to zero. copyright 1999 The American Physical Society

  2. Mirroring behavior of partial photodetachment and photoionization cross sections in the neighborhood of a resonance

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.; Starace, A.F. [Department of Physics and Astronomy, The University of Nebraska, Lincoln, Nebraska 68588-0111 (United States)

    1999-03-01

    Partial photodetachment and photoionization cross sections corresponding to highly excited residual atoms or ions are shown analytically to mirror one another in the neighborhood of a resonance. More precisely, any two groupings of partial cross sections are shown here to have components whose variations with energy near a resonance are equal in magnitude and opposite in direction. This work extends an analysis of Starace [Phys. Rev. A {bold 16}, 231 (1977)] for the behavior of partial cross sections near a resonance to the case when the {rho}{sup 2} parameter of Fano and Cooper [Phys. Rev. {bold 137}, A1364 (1965)] tends to zero. {copyright} {ital 1999} {ital The American Physical Society}

  3. Wigner-Eisenbud-Smith photoionization time delay due to autoioinization resonances

    Science.gov (United States)

    Deshmukh, P. C.; Kumar, A.; Varma, H. R.; Banerjee, S.; Manson, Steven T.; Dolmatov, V. K.; Kheifets, A. S.

    2018-03-01

    An empirical ansatz for the complex photoionization amplitude and Wigner-Eisenbud-Smith time delay in the vicinity of a Fano autoionization resonance are proposed to evaluate and interpret the time delay in the resonant region. The utility of this expression is evaluated in comparison with accurate numerical calculations employing the ab initio relativistic random phase approximation and relativistic multichannel quantum defect theory. The indisputably good qualitative agreement (and semiquantitative agreement) between corresponding results of the proposed model and results produced by the ab initio theories proves the usability of the model. In addition, the phenomenology of the time delay in the vicinity of multichannel autoionizing resonances is detailed.

  4. Nonlinear optics

    International Nuclear Information System (INIS)

    Boyd, R.W.

    1992-01-01

    Nonlinear optics is the study of the interaction of intense laser light with matter. This book is a textbook on nonlinear optics at the level of a beginning graduate student. The intent of the book is to provide an introduction to the field of nonlinear optics that stresses fundamental concepts and that enables the student to go on to perform independent research in this field. This book covers the areas of nonlinear optics, quantum optics, quantum electronics, laser physics, electrooptics, and modern optics

  5. Modeling nonlinearities in MEMS oscillators.

    Science.gov (United States)

    Agrawal, Deepak K; Woodhouse, Jim; Seshia, Ashwin A

    2013-08-01

    We present a mathematical model of a microelectromechanical system (MEMS) oscillator that integrates the nonlinearities of the MEMS resonator and the oscillator circuitry in a single numerical modeling environment. This is achieved by transforming the conventional nonlinear mechanical model into the electrical domain while simultaneously considering the prominent nonlinearities of the resonator. The proposed nonlinear electrical model is validated by comparing the simulated amplitude-frequency response with measurements on an open-loop electrically addressed flexural silicon MEMS resonator driven to large motional amplitudes. Next, the essential nonlinearities in the oscillator circuit are investigated and a mathematical model of a MEMS oscillator is proposed that integrates the nonlinearities of the resonator. The concept is illustrated for MEMS transimpedance-amplifier- based square-wave and sine-wave oscillators. Closed-form expressions of steady-state output power and output frequency are derived for both oscillator models and compared with experimental and simulation results, with a good match in the predicted trends in all three cases.

  6. Nonlinear dynamics aspects of particle accelerators

    International Nuclear Information System (INIS)

    Jowett, J.M.; Turner, S.; Month, M.

    1986-01-01

    These proceedings contain the lectures presented at the named winter school. They deal with the application of dynamical systems to accelerator theory. Especially considered are the statistical description of charged-beam plasmas, integrable and nonintegrable Hamiltonian systems, single particle dynamics and nonlinear resonances in circular accelerators, nonlinear dynamics aspects of modern storage rings, nonlinear beam-beam resonances, synchro-betatron resonances, observations of the beam-beam interactions, the dynamics of the beam-beam interactions, beam-beam simulations, the perturbation method in nonlinear dynamics, theories of statistical equilibrium in electron-positron storage rings, nonlinear dissipative phenomena in electron storage rings, the dynamical aperture, the transition to chaos for area-preserving maps, special processors for particle tracking, algorithms for tracking of charged particles in circular accelerators, the breakdown of stability, and a personal perspective of nonlinear dynamics. (HSI)

  7. Nonlinear dynamics aspects of particle accelerators. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Jowett, J M; Turner, S; Month, M

    1986-01-01

    These proceedings contain the lectures presented at the named winter school. They deal with the application of dynamical systems to accelerator theory. Especially considered are the statistical description of charged-beam plasmas, integrable and nonintegrable Hamiltonian systems, single particle dynamics and nonlinear resonances in circular accelerators, nonlinear dynamics aspects of modern storage rings, nonlinear beam-beam resonances, synchro-betatron resonances, observations of the beam-beam interactions, the dynamics of the beam-beam interactions, beam-beam simulations, the perturbation method in nonlinear dynamics, theories of statistical equilibrium in electron-positron storage rings, nonlinear dissipative phenomena in electron storage rings, the dynamical aperture, the transition to chaos for area-preserving maps, special processors for particle tracking, algorithms for tracking of charged particles in circular accelerators, the breakdown of stability, and a personal perspective of nonlinear dynamics. (HSI).

  8. Nonlinear optics

    CERN Document Server

    Bloembergen, Nicolaas

    1996-01-01

    Nicolaas Bloembergen, recipient of the Nobel Prize for Physics (1981), wrote Nonlinear Optics in 1964, when the field of nonlinear optics was only three years old. The available literature has since grown by at least three orders of magnitude.The vitality of Nonlinear Optics is evident from the still-growing number of scientists and engineers engaged in the study of new nonlinear phenomena and in the development of new nonlinear devices in the field of opto-electronics. This monograph should be helpful in providing a historical introduction and a general background of basic ideas both for expe

  9. Structural optimization for nonlinear dynamic response

    DEFF Research Database (Denmark)

    Dou, Suguang; Strachan, B. Scott; Shaw, Steven W.

    2015-01-01

    by a single vibrating mode, or by a pair of internally resonant modes. The approach combines techniques from nonlinear dynamics, computational mechanics and optimization, and it allows one to relate the geometric and material properties of structural elements to terms in the normal form for a given resonance......Much is known about the nonlinear resonant response of mechanical systems, but methods for the systematic design of structures that optimize aspects of these responses have received little attention. Progress in this area is particularly important in the area of micro-systems, where nonlinear...... resonant behaviour is being used for a variety of applications in sensing and signal conditioning. In this work, we describe a computational method that provides a systematic means for manipulating and optimizing features of nonlinear resonant responses of mechanical structures that are described...

  10. Probing hysteretic elasticity in weakly nonlinear materials

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Paul A [Los Alamos National Laboratory; Haupert, Sylvain [UPMC UNIV PARIS; Renaud, Guillaume [UPMC UNIV PARIS; Riviere, Jacques [UPMC UNIV PARIS; Talmant, Maryline [UPMC UNIV PARIS; Laugier, Pascal [UPMC UNIV PARIS

    2010-12-07

    Our work is aimed at assessing the elastic and dissipative hysteretic nonlinear parameters' repeatability (precision) using several classes of materials with weak, intermediate and high nonlinear properties. In this contribution, we describe an optimized Nonlinear Resonant Ultrasound Spectroscopy (NRUS) measuring and data processing protocol applied to small samples. The protocol is used to eliminate the effects of environmental condition changes that take place during an experiment, and that may mask the intrinsic elastic nonlinearity. As an example, in our experiments, we identified external temperature fluctuation as a primary source of material resonance frequency and elastic modulus variation. A variation of 0.1 C produced a frequency variation of 0.01 %, which is similar to the expected nonlinear frequency shift for weakly nonlinear materials. In order to eliminate environmental effects, the variation in f{sub 0} (the elastically linear resonance frequency proportional to modulus) is fit with the appropriate function, and that function is used to correct the NRUS calculation of nonlinear parameters. With our correction procedure, we measured relative resonant frequency shifts of 10{sup -5} , which are below 10{sup -4}, often considered the limit to NRUS sensitivity under common experimental conditions. Our results show that the procedure is an alternative to the stringent control of temperature often applied. Applying the approach, we report nonlinear parameters for several materials, some with very small nonclassical nonlinearity. The approach has broad application to NRUS and other Nonlinear Elastic Wave Spectroscopy approaches.

  11. El acoso psicológico en los quirófanos. Mobbingin operating theatres.

    Directory of Open Access Journals (Sweden)

    Susana Azzollini

    2005-12-01

    Full Text Available Se realizó un estudio comparativo, descriptivo, prospec-tivo, de corte transversal con el objetivo de determinar el acoso psicológico reflejado en el estilo comunicacional del cirujano hacia el personal no médico en el quirófano de dos instituciones, una pública y la otra privada. Las hipótesis fueron: a cuanto más desfavorables sean las características de la situación, más inadecuado será el estilo comunicacional, favoreciendo la aparición de acoso psicológico hacia el personal no médico; b los cirujanos que no tengan un cargo de jefes y sean adultos jóvenes presentarán un estilo comunicacional inadecuado, favoreciendo la aparición de acoso psicológico y; c existirá un estilo comunicacional más inadecuado y con mayor presencia de acoso psicológico en la institución privada que en la institución pública. Se construyó una lista de control para observar el estilo comunicacional de los cirujanos durante la intervención quirúrgica y un cuestionario de datos personales que fueron aplicados a una muestra no probabilística intencional de 30 cirujanos de cada institución. Se analizaron los datos utilizando estadística descriptiva y se realizaron análisis bivariados para probar hipótesis. Los resultados evidencian que el acoso psicológico es una práctica generalizada en los quirófanos, que se da más en los cirujanos cardiovasculares que en las otras especialidades. Además, se produce en mayor medida en la institución privada que en la pública y el acosador no suele tener un cargo jerárquico.The aim of this comparative transversal court study was to make out the mobbing reflected by the communicational style of surgeon towards no medical staff inside two institutions: a public and a private one. The hypothesis were: a the more harmful the situation, the more inadequate the communicational style, allowing the show up of mobbing towards the no medical staff. b Young surgeons who weren't heads of department will

  12. Fano-like resonance and scattering in dielectric(core)–metal(shell) composites embedded in active host matrices

    CSIR Research Space (South Africa)

    Jule, L

    2015-07-01

    Full Text Available We investigate light scattering by core–shell consisting of metal/dielectric composites considering spherical and cylindrical nanoinclusions, within the framework of the conventional Rayleigh approximation. By writing the electric potential...

  13. Nonlinear NDT: A Route to Conventional Ultrasonic Testing

    OpenAIRE

    Igor Solodov

    2016-01-01

    The bottleneck problem of nonlinear NDT is a low efficiency of conversion from fundamental frequency to nonlinear frequency components. In this paper, it is proposed to use a combination of nonlinearity with Local Defect Resonance (LDR) to enhance substantially the input-output conversion. Since LDR is an efficient resonance “amplifier” of the local vibrations, it manifests a profound nonlinearity even at moderate ultrasonic excitation level. As the driving frequency matches the LDR-frequency...

  14. From Feshbach-resonance managed Bose-Einstein condensates to anisotropic universes: Applications of the Ermakov-Pinney equation with time-dependent nonlinearity

    International Nuclear Information System (INIS)

    Herring, G.; Kevrekidis, P.G.; Williams, F.; Christodoulakis, T.; Frantzeskakis, D.J.

    2008-01-01

    In this work we revisit the topic of two-dimensional Bose-Einstein condensates under the influence of time-dependent magnetic confinement and time-dependent scattering length. A moment approach reduces the examination of moments of the wavefunction (in particular, of its width) to an Ermakov-Pinney (EP) ordinary differential equation (ODE). We use the well-known structure of the solutions of this nonlinear ODE to 'engineer' trapping and interatomic interaction conditions that lead to condensates dispersing, breathing or even collapsing. The advantage of the approach is that it is fully tractable analytically, in excellent agreement with our numerical observations. As an aside, we also discuss how similar time-dependent EP equations may arise in the description of anisotropic scalar field cosmologies

  15. From Feshbach-resonance managed Bose-Einstein condensates to anisotropic universes: Applications of the Ermakov-Pinney equation with time-dependent nonlinearity

    International Nuclear Information System (INIS)

    Herring, G.; Kevrekidis, P.G.; Williams, F.; Christodoulakis, T.; Frantzeskakis, D.J.

    2007-01-01

    In this work we revisit the topic of two-dimensional Bose-Einstein condensates under the influence of time-dependent magnetic confinement and time-dependent scattering length. A moment approach reduces the examination of moments of the wavefunction (in particular, of its width) to an Ermakov-Pinney (EP) ordinary differential equation (ODE). We use the well-known structure of the solutions of this nonlinear ODE to 'engineer' trapping and interatomic interaction conditions that lead to condensates dispersing, breathing or even collapsing. The advantage of the approach is that it is fully tractable analytically, in excellent agreement with our numerical observations. As an aside, we also discuss how similar time-dependent EP equations may arise in the description of anisotropic scalar field cosmologies

  16. Acoustic superlens using Helmholtz-resonator-based metamaterials

    International Nuclear Information System (INIS)

    Yang, Xishan; Yin, Jing; Yu, Gaokun; Peng, Linhui; Wang, Ning

    2015-01-01

    Acoustic superlens provides a way to overcome the diffraction limit with respect to the wavelength of the bulk wave in air. However, the operating frequency range of subwavelength imaging is quite narrow. Here, an acoustic superlens is designed using Helmholtz-resonator-based metamaterials to broaden the bandwidth of super-resolution. An experiment is carried out to verify subwavelength imaging of double slits, the imaging of which can be well resolved in the frequency range from 570 to 650 Hz. Different from previous works based on the Fabry-Pérot resonance, the corresponding mechanism of subwavelength imaging is the Fano resonance, and the strong coupling between the neighbouring Helmholtz resonators separated at the subwavelength interval leads to the enhanced sound transmission over a relatively wide frequency range

  17. Pairing and condensation in a resonant Bose-Fermi mixture

    International Nuclear Information System (INIS)

    Fratini, Elisa; Pieri, Pierbiagio

    2010-01-01

    We study by diagrammatic means a Bose-Fermi mixture, with boson-fermion coupling tuned by a Fano-Feshbach resonance. For increasing coupling, the growing boson-fermion pairing correlations progressively reduce the boson condensation temperature and make it eventually vanish at a critical coupling. Such quantum critical point depends very weakly on the population imbalance and, for vanishing boson densities, coincides with that found for the polaron-molecule transition in a strongly imbalanced Fermi gas, thus bridging two quite distinct physical systems.

  18. Nonlinear Science

    CERN Document Server

    Yoshida, Zensho

    2010-01-01

    This book gives a general, basic understanding of the mathematical structure "nonlinearity" that lies in the depths of complex systems. Analyzing the heterogeneity that the prefix "non" represents with respect to notions such as the linear space, integrability and scale hierarchy, "nonlinear science" is explained as a challenge of deconstruction of the modern sciences. This book is not a technical guide to teach mathematical tools of nonlinear analysis, nor a zoology of so-called nonlinear phenomena. By critically analyzing the structure of linear theories, and cl

  19. Nonlinear oscillations

    CERN Document Server

    Nayfeh, Ali Hasan

    1995-01-01

    Nonlinear Oscillations is a self-contained and thorough treatment of the vigorous research that has occurred in nonlinear mechanics since 1970. The book begins with fundamental concepts and techniques of analysis and progresses through recent developments and provides an overview that abstracts and introduces main nonlinear phenomena. It treats systems having a single degree of freedom, introducing basic concepts and analytical methods, and extends concepts and methods to systems having degrees of freedom. Most of this material cannot be found in any other text. Nonlinear Oscillations uses sim

  20. Resonance phenomenon in classical cepheids

    International Nuclear Information System (INIS)

    Takeuti, Mine; Aikawa, Toshiki

    1981-01-01

    To investigate resonance phenomenon in classical cepheids, the non-linear radial oscillation of stars is studied based on the assumption that the non-adiabatic perturbation is expressed in terms of van der Pol's type damping. Two- and three-wave resonance in this system is applied to classical cepheids to describe their bump and double-mode behavior. The phase of bump and the depression of amplitude are explained for bump cepheids. The double-periodicity is shown by the enhancement of the third overtone in three-wave resonance. Non-linear effect on resonant period is also discussed briefly. (author)

  1. Families of Smooth Rational Curves of Small Degree on the Fano Variety of Degree 5 of Main Series

    Directory of Open Access Journals (Sweden)

    M. S. Omelkova

    2013-01-01

    Full Text Available In this paper we consider some families of smooth rational curves of degree 2, 3 and 4 on a smooth Fano threefold X which is a linear section of the Grassmanian G(1, 4 under the Pl¨ucker embedding. We prove that these families are irreducible. The proof of the irreducibility of the families of curves of degree d is based on the study of degeneration of a rational curve of degree d into a curve which decomposes into an irreducible rational curve of degree d−1 and a projective line intersecting transversally at a point. We prove that the Hilbert scheme of curves of degree d on X is smooth at the point corresponding to such a reducible curve. Then calculations in the framework of deformation theory show that such a curve varies into a smooth rational curve of degree d. Thus, the set of reducible curves of degree d of the above type lies in the closure of a unique component of the Hilbert scheme of smooth rational curves of degree d on X. From this fact and the irreducibility of the Hilbert scheme of smooth rational curves of degree d on the Grassmannian G(1, 4 one deduces the irreducibility of the Hilbert scheme of smooth rational curves of degree d on a general Fano threefold X.

  2. Nonlinear systems

    CERN Document Server

    Palmero, Faustino; Lemos, M; Sánchez-Rey, Bernardo; Casado-Pascual, Jesús

    2018-01-01

    This book presents an overview of the most recent advances in nonlinear science. It provides a unified view of nonlinear properties in many different systems and highlights many  new developments. While volume 1 concentrates on mathematical theory and computational techniques and challenges, which are essential for the study of nonlinear science, this second volume deals with nonlinear excitations in several fields. These excitations can be localized and transport energy and matter in the form of breathers, solitons, kinks or quodons with very different characteristics, which are discussed in the book. They can also transport electric charge, in which case they are known as polarobreathers or solectrons. Nonlinear excitations can influence function and structure in biology, as for example, protein folding. In crystals and other condensed matter, they can modify transport properties, reaction kinetics and interact with defects. There are also engineering applications in electric lattices, Josephson junction a...

  3. Periodic precursors of nonlinear dynamical transitions

    International Nuclear Information System (INIS)

    Jiang Yu; Dong Shihai; Lozada-Cassou, M.

    2004-01-01

    We study the resonant response of a nonlinear system to external periodic perturbations. We show by numerical simulation that the periodic resonance curve may anticipate the dynamical instability of the unperturbed nonlinear periodic system, at parameter values far away from the bifurcation points. In the presence of noise, the buried intrinsic periodic dynamics can be picked out by analyzing the system's response to periodic modulation of appropriate intensity

  4. Inducción de la enzima triptófano 2,3 dioxigenasa por glucocorticoides y su papel en la tolerancia materna al feto

    Directory of Open Access Journals (Sweden)

    Angela Cadavid

    2004-02-01

    Full Text Available

    El mecanismo por el cual la madre no rechaza al feto, sigue siendo una incógnita en la inmunología de la reproducción. Una de las hipótesis planteadas es la inmunosupresión mediada por el catabolismo del triptófano, el cual es un amino ácido sencial para la proliferación de los linfocitos T. Una de las nzimas que cataboliza el triptófano es la triptófano 2,3 ioxigenasa (TDO.
    La TDO es inducida por los glucocorticoides en el hígado, pero aún no se conoce si estos inducen la producción de la TDO n la interfase materno fetal al interactuar con los receptores resentes en células estromales y NK; En un modelo murino, e observó que la TDO se expresa en la interfase materno etal con un pico que coincide con el de mayor actividad de egradación del triptófano, sugiriendo entonces que esta nzima puede estar involucrada en la tolerancia materna al feto.

     

     

  5. Waves and Structures in Nonlinear Nondispersive Media General Theory and Applications to Nonlinear Acoustics

    CERN Document Server

    Gurbatov, S N; Saichev, A I

    2012-01-01

    "Waves and Structures in Nonlinear Nondispersive Media: General Theory and Applications to Nonlinear Acoustics” is devoted completely to nonlinear structures. The general theory is given here in parallel with mathematical models. Many concrete examples illustrate the general analysis of Part I. Part II is devoted to applications to nonlinear acoustics, including specific nonlinear models and exact solutions, physical mechanisms of nonlinearity, sawtooth-shaped wave propagation, self-action phenomena, nonlinear resonances and engineering application (medicine, nondestructive testing, geophysics, etc.). This book is designed for graduate and postgraduate students studying the theory of nonlinear waves of various physical nature. It may also be useful as a handbook for engineers and researchers who encounter the necessity of taking nonlinear wave effects into account of their work. Dr. Gurbatov S.N. is the head of Department, and Vice Rector for Research of Nizhny Novgorod State University. Dr. Rudenko O.V. is...

  6. Solitons and Weakly Nonlinear Waves in Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans

    1985-01-01

    Theoretical descriptions of solitons and weakly nonlinear waves propagating in plasma media are reviewed, with particular attention to the Korteweg-de Vries (KDV) equation and the Nonlinear Schrödinger equation (NLS). The modifications of these basic equations due to the effects of resonant...

  7. PT -symmetric dimer of coupled nonlinear oscillators

    Indian Academy of Sciences (India)

    We provide a systematic analysis of a prototypical nonlinear oscillator ... recently, a number of nonlinear variants have been explored, like split-ring resonator chain .... Note that these solutions are valid for any value of ǫ (and hence δ) including ǫ ..... [16] M Abramowitz and I A Stegun, Handbook of mathematical functions ...

  8. Nonlinear optics

    CERN Document Server

    Boyd, Robert W

    2013-01-01

    Nonlinear Optics is an advanced textbook for courses dealing with nonlinear optics, quantum electronics, laser physics, contemporary and quantum optics, and electrooptics. Its pedagogical emphasis is on fundamentals rather than particular, transitory applications. As a result, this textbook will have lasting appeal to a wide audience of electrical engineering, physics, and optics students, as well as those in related fields such as materials science and chemistry.Key Features* The origin of optical nonlinearities, including dependence on the polarization of light* A detailed treatment of the q

  9. Nonlinear systems

    National Research Council Canada - National Science Library

    Drazin, P. G

    1992-01-01

    This book is an introduction to the theories of bifurcation and chaos. It treats the solution of nonlinear equations, especially difference and ordinary differential equations, as a parameter varies...

  10. Nonlinear analysis

    CERN Document Server

    Gasinski, Leszek

    2005-01-01

    Hausdorff Measures and Capacity. Lebesgue-Bochner and Sobolev Spaces. Nonlinear Operators and Young Measures. Smooth and Nonsmooth Analysis and Variational Principles. Critical Point Theory. Eigenvalue Problems and Maximum Principles. Fixed Point Theory.

  11. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  12. 4th International Conference on Structural Nonlinear Dynamics and Diagnosis

    CERN Document Server

    2018-01-01

    This book presents contributions on the most active lines of recent advanced research in the field of nonlinear mechanics and physics selected from the 4th International Conference on Structural Nonlinear Dynamics and Diagnosis. It includes fifteen chapters by outstanding scientists, covering various aspects of applications, including road tanker dynamics and stability, simulation of abrasive wear, energy harvesting, modeling and analysis of flexoelectric nanoactuator, periodic Fermi–Pasta–Ulam problems, nonlinear stability in Hamiltonian systems, nonlinear dynamics of rotating composites, nonlinear vibrations of a shallow arch, extreme pulse dynamics in mode-locked lasers, localized structures in a photonic crystal fiber resonator, nonlinear stochastic dynamics, linearization of nonlinear resonances, treatment of a linear delay differential equation, and fractional nonlinear damping. It appeals to a wide range of experts in the field of structural nonlinear dynamics and offers researchers and engineers a...

  13. Nonlinear dynamic characterization of two-dimensional materials

    NARCIS (Netherlands)

    Davidovikj, D.; Alijani, F.; Cartamil Bueno, S.J.; van der Zant, H.S.J.; Amabili, M.; Steeneken, P.G.

    2017-01-01

    Owing to their atomic-scale thickness, the resonances of two-dimensional (2D) material membranes show signatures of nonlinearities at forces of only a few picoNewtons. Although the linear dynamics of membranes is well understood, the exact relation between the nonlinear response and the resonator's

  14. Nonlinear calculations for BL Her stars

    International Nuclear Information System (INIS)

    Hodson, S.W.; Cox, A.N.; King, D.S.

    1980-01-01

    From the linear and nonlinear calculations it is evident that bumps occur in the velocity and light curves when there is a near resonance between π 0 and π 2 . In addition, these resonance bumps do not seem to depend on the limit cycle amplitude, and cannot be attributed to the surface shock encountered when models are driven to excessively high amplitudes

  15. Fano-Agarwal couplings and non-rotating wave approximation in single-photon timed Dicke subradiance

    Science.gov (United States)

    Mirza, Imran M.; Begzjav, Tuguldur

    2016-04-01

    Recently a new class of single-photon timed Dicke (TD) subradiant states has been introduced with possible applications in single-photon-based quantum information storage and on demand ultrafast retrieval (Scully M. O., Phys. Rev. Lett., 115 (2015) 243602). However, the influence of any kind of virtual processes on the decay of these new kind of subradiant states has been left as an open question. In the present paper, we focus on this problem in detail. In particular, we investigate how pure Fano-Agarwal couplings and other virtual processes arising from non-rotating wave approximation impact the decay of otherwise sub- and superradiant states. In addition to the overall virtual couplings among all TD states, we also focus on the dominant role played by the couplings between specific TD states.

  16. Bound states in the continuum and Fano antiresonance in electronic transport through a four-quantum-dot system

    International Nuclear Information System (INIS)

    Yan Junxia; Fu Huahua

    2013-01-01

    We study the electronic transport through a four-quantum-dot (FQD) structure with a diamond-like shape through nonequilibrium Green's function theory. It is observed that the bound state in the continuum (BIC) appears in this multiple QDs system, and the position of the BIC in the total density of states (TDOS) spectrum is tightly determined by the strength of the electronic hopping between the upper QD and the lower one. As the symmetry in the energy levels in these two QDs is broken, the BIC is suppressed to a general conductance peak with a finite width, and meanwhile a Fano-type antiresonance with a zero point appears in the conductance spectrum. These results will develop our understanding of the BICs and their spintronic device applications of spin filter and quantum computing.

  17. Device Applications of Nonlinear Dynamics

    CERN Document Server

    Baglio, Salvatore

    2006-01-01

    This edited book is devoted specifically to the applications of complex nonlinear dynamic phenomena to real systems and device applications. While in the past decades there has been significant progress in the theory of nonlinear phenomena under an assortment of system boundary conditions and preparations, there exist comparatively few devices that actually take this rich behavior into account. "Device Applications of Nonlinear Dynamics" applies and exploits this knowledge to make devices which operate more efficiently and cheaply, while affording the promise of much better performance. Given the current explosion of ideas in areas as diverse as molecular motors, nonlinear filtering theory, noise-enhanced propagation, stochastic resonance and networked systems, the time is right to integrate the progress of complex systems research into real devices.

  18. Photoabsorption and S 2p photoionization of the SF6 molecule: resonances in the excitation energy range of 200-280 eV.

    Science.gov (United States)

    Stener, M; Bolognesi, P; Coreno, M; O'Keeffe, P; Feyer, V; Fronzoni, G; Decleva, P; Avaldi, L; Kivimäki, A

    2011-05-07

    Photoabsorption and S 2p photoionization of the SF(6) molecule have been studied experimentally and theoretically in the excitation energy range up to 100 eV above the S 2p ionization potentials. In addition to the well-known 2t(2g) and 4e(g) shape resonances, the spin-orbit-resolved S 2p photoionization cross sections display two weak resonances between 200 and 210 eV, a wide resonance around 217 eV, a Fano-type resonance around 240 eV, and a second wide resonance around 260 eV. Calculations based on time-dependent density functional theory allow us to assign the 217-eV and 260-eV features to the shape resonances in S 2p photoionization. The Fano resonance is caused by the interference between the direct S 2p photoionization channel and the resonant channel that results from the participator decay of the S 2s(-1)6t(1u) excited state. The weak resonances below 210-eV photon energy, not predicted by theory, are tentatively suggested to originate from the coupling between S 2p shake-up photoionization and S 2p single-hole photoionization. The experimental and calculated angular anisotropy parameters for S 2p photoionization are in good agreement.

  19. Behavior of partial cross sections and branching ratios in the neighborhood of a resonance

    International Nuclear Information System (INIS)

    Starace, A.F.

    1977-01-01

    Starting from the treatment of Fano for the behavior of the total cross section in a photoionization (or electron-ion scattering) experiment in the vicinity of a resonance, we present a theoretical formula for the behavior of an individual final-state channel in the neighborhood of a resonance. This result is then used to derive another theoretical formula for the behavior of the ratio of two partial cross sections (i.e., the branching ratio) in the vicinity of a resonance. This branching-ratio formula depends on the profile parameters q, GAMMA, and rho 2 for the resonance, on the branching ratio outside the resonance, and on two new parameters which are explicitly related to scattering-matrix elements and phase shifts

  20. Nonlinear optimization

    CERN Document Server

    Ruszczynski, Andrzej

    2011-01-01

    Optimization is one of the most important areas of modern applied mathematics, with applications in fields from engineering and economics to finance, statistics, management science, and medicine. While many books have addressed its various aspects, Nonlinear Optimization is the first comprehensive treatment that will allow graduate students and researchers to understand its modern ideas, principles, and methods within a reasonable time, but without sacrificing mathematical precision. Andrzej Ruszczynski, a leading expert in the optimization of nonlinear stochastic systems, integrates the theory and the methods of nonlinear optimization in a unified, clear, and mathematically rigorous fashion, with detailed and easy-to-follow proofs illustrated by numerous examples and figures. The book covers convex analysis, the theory of optimality conditions, duality theory, and numerical methods for solving unconstrained and constrained optimization problems. It addresses not only classical material but also modern top...

  1. Photonic surfaces for designable nonlinear power shaping

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Roshni, E-mail: rbiswas@usc.edu; Povinelli, Michelle L. [Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States)

    2015-02-09

    We propose a method for designing nonlinear input-output power response based on absorptive resonances of nanostructured surfaces. We show that various power transmission trends can be obtained by placing a photonic resonance mode at the appropriate detuning from the laser wavelength. We demonstrate our results in a silicon photonic crystal slab at a laser wavelength of 808 nm. We quantify the overall spectral red shift as a function of laser power. The shift results from absorptive heating and the thermo-optic effect. We then demonstrate devices with increasing, decreasing, and non-monotonic transmission as a function of laser power. The transmission changes are up to 7.5 times larger than in unpatterned silicon. The strong nonlinear transmission is due to a combination of resonantly enhanced absorption, reduced thermal conductivity, and the resonant transmission lineshape. Our results illustrate the possibility of designing different nonlinear power trends within a single materials platform at a given wavelength of interest.

  2. Photonic surfaces for designable nonlinear power shaping

    International Nuclear Information System (INIS)

    Biswas, Roshni; Povinelli, Michelle L.

    2015-01-01

    We propose a method for designing nonlinear input-output power response based on absorptive resonances of nanostructured surfaces. We show that various power transmission trends can be obtained by placing a photonic resonance mode at the appropriate detuning from the laser wavelength. We demonstrate our results in a silicon photonic crystal slab at a laser wavelength of 808 nm. We quantify the overall spectral red shift as a function of laser power. The shift results from absorptive heating and the thermo-optic effect. We then demonstrate devices with increasing, decreasing, and non-monotonic transmission as a function of laser power. The transmission changes are up to 7.5 times larger than in unpatterned silicon. The strong nonlinear transmission is due to a combination of resonantly enhanced absorption, reduced thermal conductivity, and the resonant transmission lineshape. Our results illustrate the possibility of designing different nonlinear power trends within a single materials platform at a given wavelength of interest

  3. Nonlinear Electron Waves in Strongly Magnetized Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans; Juul Rasmussen, Jens

    1980-01-01

    Weakly nonlinear dispersive electron waves in strongly magnetized plasma are considered. A modified nonlinear Schrodinger equation is derived taking into account the effect of particles resonating with the group velocity of the waves (nonlinear Landau damping). The possibility of including the ion...... dynamics in the analysis is also demonstrated. As a particular case the authors investigate nonlinear waves in a strongly magnetized plasma filled wave-guide, where the effects of finite geometry are important. The relevance of this problem to laboratory experiments is discussed....

  4. Nonlinear optics quantum computing with circuit QED.

    Science.gov (United States)

    Adhikari, Prabin; Hafezi, Mohammad; Taylor, J M

    2013-02-08

    One approach to quantum information processing is to use photons as quantum bits and rely on linear optical elements for most operations. However, some optical nonlinearity is necessary to enable universal quantum computing. Here, we suggest a circuit-QED approach to nonlinear optics quantum computing in the microwave regime, including a deterministic two-photon phase gate. Our specific example uses a hybrid quantum system comprising a LC resonator coupled to a superconducting flux qubit to implement a nonlinear coupling. Compared to the self-Kerr nonlinearity, we find that our approach has improved tolerance to noise in the qubit while maintaining fast operation.

  5. Numerical study of surface plasmon enhanced nonlinear absorption and refraction.

    Science.gov (United States)

    Kohlgraf-Owens, Dana C; Kik, Pieter G

    2008-07-07

    Maxwell Garnett effective medium theory is used to study the influence of silver nanoparticle induced field enhancement on the nonlinear response of a Kerr-type nonlinear host. We show that the composite nonlinear absorption coefficient, beta(c), can be enhanced relative to the host nonlinear absorption coefficient near the surface plasmon resonance of silver nanoparticles. This enhancement is not due to a resonant enhancement of the host nonlinear absorption, but rather due to a phase shifted enhancement of the host nonlinear refractive response. The enhancement occurs at the expense of introducing linear absorption, alpha(c), which leads to an overall reduced figure of merit beta(c)/alpha(c) for nonlinear absorption. For thin (< 1 microm) composites, the use of surface plasmons is found to result in an increased nonlinear absorption response compared to that of the host material.

  6. Amplitude saturation of MEMS resonators explained by autoparametric resonance

    International Nuclear Information System (INIS)

    Van der Avoort, C; Bontemps, J J M; Steeneken, P G; Le Phan, K; Van Beek, J T M; Van der Hout, R; Hulshof, J; Fey, R H B

    2010-01-01

    This paper describes a phenomenon that limits the power handling of MEMS resonators. It is observed that above a certain driving level, the resonance amplitude becomes independent of the driving level. In contrast to previous studies of power handling of MEMS resonators, it is found that this amplitude saturation cannot be explained by nonlinear terms in the spring constant or electrostatic force. Instead we show that the amplitude in our experiments is limited by nonlinear terms in the equation of motion which couple the in-plane length-extensional resonance mode to one or more out-of-plane (OOP) bending modes. We present experimental evidence for the autoparametric excitation of these OOP modes using a vibrometer. The measurements are compared to a model that can be used to predict a power-handling limit for MEMS resonators

  7. Amplitude saturation of MEMS resonators explained by autoparametric resonance

    Energy Technology Data Exchange (ETDEWEB)

    Van der Avoort, C; Bontemps, J J M; Steeneken, P G; Le Phan, K; Van Beek, J T M [NXP Research, Eindhoven (Netherlands); Van der Hout, R; Hulshof, J [Department of Mathematics, VU University—Faculty of Sciences, De Boelelaan 1081a, 1081 HV Amsterdam (Netherlands); Fey, R H B, E-mail: cas.van.der.avoort@nxp.com [Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven (Netherlands)

    2010-10-15

    This paper describes a phenomenon that limits the power handling of MEMS resonators. It is observed that above a certain driving level, the resonance amplitude becomes independent of the driving level. In contrast to previous studies of power handling of MEMS resonators, it is found that this amplitude saturation cannot be explained by nonlinear terms in the spring constant or electrostatic force. Instead we show that the amplitude in our experiments is limited by nonlinear terms in the equation of motion which couple the in-plane length-extensional resonance mode to one or more out-of-plane (OOP) bending modes. We present experimental evidence for the autoparametric excitation of these OOP modes using a vibrometer. The measurements are compared to a model that can be used to predict a power-handling limit for MEMS resonators.

  8. Nonlinear hybridization of the fundamental eigenmodes of microscopic ferromagnetic ellipses.

    Science.gov (United States)

    Demidov, V E; Buchmeier, M; Rott, K; Krzysteczko, P; Münchenberger, J; Reiss, G; Demokritov, S O

    2010-05-28

    We have studied experimentally with high spatial resolution the nonlinear eigenmodes of microscopic Permalloy elliptical elements. We show that the nonlinearity affects the frequencies of the edge and the center modes in an essentially different way. This leads to repulsion of corresponding resonances and to nonlinear mode hybridization resulting in qualitative modifications of the spatial characteristics of the modes. We find that the nonlinear counterparts of the edge and the center modes simultaneously exhibit features specific for both their linear analogues.

  9. Nonlinear Hybridization of the Fundamental Eigenmodes of Microscopic Ferromagnetic Ellipses

    OpenAIRE

    Demidov, V. E.; Buchmeier, M.; Rott, Karsten; Krzysteczko, Patryk; Münchenberger, Jana; Reiss, Günter; Demokritov, S. O.

    2010-01-01

    We have studied experimentally with high spatial resolution the nonlinear eigenmodes of microscopic Permalloy elliptical elements. We show that the nonlinearity affects the frequencies of the edge and the center modes in an essentially different way. This leads to repulsion of corresponding resonances and to nonlinear mode hybridization resulting in qualitative modifications of the spatial characteristics of the modes. We find that the nonlinear counterparts of the edge and the center modes s...

  10. 190. Extubación en el Quirófano Como Rutina Tras Cirugía Cardíaca: 500 Casos Consecutivos

    Directory of Open Access Journals (Sweden)

    A. Ysasi

    2012-04-01

    Conclusiones: la extubación en el quirófano de forma rutinaria en pacientes sometidos a cirugía cardíaca es viable y segura. La necesidad de reintubación o reingreso en UCI es baja. Contribuye a la recuperación precoz del paciente y disminuye los tiempos de estancia y consumo de recursos hospitalarios.

  11. ¿Es posible tener un incendio en un quirófano? Is it possible to have a fire in an operating theatre?

    Directory of Open Access Journals (Sweden)

    Juan José Agún González

    2010-03-01

    Full Text Available Podemos pensar que un quirófano es el Sancta Sanctorum de un Hospital, el sitio más "seguro" dentro del entorno más controlado, en todos los aspectos. Pero, es un hecho contrastado, aunque no siempre difundido, que los incendios en quirófano existen y suelen ser por causas internas al propio quirófano. Durante una intervención quirúrgica tenemos una posibilidad de sufrir un incendio en el momento más peligroso de la vida de un paciente y crear una situación de emergencia en un área crítica. Los objetivos de esta investigación son: - Incidir en la posibilidad de tener un incendio en quirófano. - Analizar las posibilidades del riesgo. - Detectar conductas y elementos peligrosos. - Analizar las medidas preventivas a adoptar.We might think that an operating theatre is the sanctum sanctorum of a Hospital. The 'safest' place within a very much controlled environment in all aspects. But it is a contrasted fact, although not always published, that fires in operating theatres exist and that they are normally caused by situations in the operating theatre itself. During an operation there is the possibility of having a fire in the most dangerous moment for the life of a patient and in the most critical zones of a hospital. The objectives of this research are the following: - To emphasize the possibility of fire in an operating theatre - To analyse the possibilities of risk - To detect hazardous elements and behaviour - To analyse the preventive measures to be adopted

  12. Effect of Forcing Function on Nonlinear Acoustic Standing Waves

    Science.gov (United States)

    Finkheiner, Joshua R.; Li, Xiao-Fan; Raman, Ganesh; Daniels, Chris; Steinetz, Bruce

    2003-01-01

    Nonlinear acoustic standing waves of high amplitude have been demonstrated by utilizing the effects of resonator shape to prevent the pressure waves from entering saturation. Experimentally, nonlinear acoustic standing waves have been generated by shaking an entire resonating cavity. While this promotes more efficient energy transfer than a piston-driven resonator, it also introduces complicated structural dynamics into the system. Experiments have shown that these dynamics result in resonator forcing functions comprised of a sum of several Fourier modes. However, previous numerical studies of the acoustics generated within the resonator assumed simple sinusoidal waves as the driving force. Using a previously developed numerical code, this paper demonstrates the effects of using a forcing function constructed with a series of harmonic sinusoidal waves on resonating cavities. From these results, a method will be demonstrated which allows the direct numerical analysis of experimentally generated nonlinear acoustic waves in resonators driven by harmonic forcing functions.

  13. Fano-type coupling of a bound paramagnetic state with 2D continuum

    International Nuclear Information System (INIS)

    Rozhansky, I. V.; Averkiev, N. S.; Lähderanta, E.

    2013-01-01

    We analyze an effect of a bound impurity state located at a tunnel distance from a quantum well (QW). The study is focused on the resonance case when the bound state energy lies within the continuum of the QW states. Using the developed theory we calculate spin polarization of 2D holes induced by paramagnetic (Mn) delta-layer in the vicinity of the QW and indirect exchange interaction between two impurities located at a tunnel distance from electron gas

  14. Photoemission study of Kr 3d→np autoionization resonances

    International Nuclear Information System (INIS)

    Lindle, D.W.; Heimann, P.A.; Ferrett, T.A.; Piancastelli, M.N.; Shirley, D.A.

    1987-01-01

    Resonant photoelectron spectra of Kr have been taken in the photon-energy ranges of the 3d/sub 5/2/→5p,6p and 3d/sub 3/2/→5p excitations. The spectra, which closely resemble normal Kr + 3d/sup -1/ Auger spectra, illustrate the importance of ''spectator'' Auger-like decay for inner-shell resonances, in which the initially excited electron does not participate in the core-hole deexcitation process, except to respond to the change in the atomic potential. Possible assignments for some of the spectator decay channels are discussed based on photoemission intensity measurements at the different 3d resonances. These assignments suggest that shake-up (e.g., 5p→6p) of the ''spectator'' electron during the decay process is not quite as important as previously suspected. The resonance profiles of some of the more intense satellites have been determined over the 3d→np resonances. Very small resonance effects also were observed in the partial cross section for 4p subshell ionization, which produced asymmetric Fano-type profiles. The 4p angular distribution, in contrast, exhibits a pronounced effect in the resonance energy range. The 4p results demonstrate that nonspectator autoionization also is present

  15. Cascaded nonlinearities for ultrafast nonlinear optical science and applications

    DEFF Research Database (Denmark)

    Bache, Morten

    the cascading nonlinearity is investigated in detail, especially with focus on femtosecond energetic laser pulses being subjected to this nonlinear response. Analytical, numerical and experimental results are used to understand the cascading interaction and applications are demonstrated. The defocusing soliton...... observations with analogies in fiber optics are observed numerically and experimentally, including soliton self-compression, soliton-induced resonant radiation, supercontinuum generation, optical wavebreaking and shock-front formation. All this happens despite no waveguide being present, thanks...... is of particular interest here, since it is quite unique and provides the solution to a number of standing challenges in the ultrafast nonlinear optics community. It solves the problem of catastrophic focusing and formation of a filaments in bulk glasses, which even under controlled circumstances is limited...

  16. Far from Equilibrium Percolation, Stochastic and Shape Resonances in the Physics of Life

    Directory of Open Access Journals (Sweden)

    Antonio Bianconi

    2011-10-01

    Full Text Available Key physical concepts, relevant for the cross-fertilization between condensed matter physics and the physics of life seen as a collective phenomenon in a system out-of-equilibrium, are discussed. The onset of life can be driven by: (a the critical fluctuations at the protonic percolation threshold in membrane transport; (b the stochastic resonance in biological systems, a mechanism that can exploit external and self-generated noise in order to gain efficiency in signal processing; and (c the shape resonance (or Fano resonance or Feshbach resonance in the association and dissociation processes of bio-molecules (a quantum mechanism that could play a key role to establish a macroscopic quantum coherence in the cell.

  17. An efficient nonlinear Feshbach engine

    Science.gov (United States)

    Li, Jing; Fogarty, Thomás; Campbell, Steve; Chen, Xi; Busch, Thomas

    2018-01-01

    We investigate a thermodynamic cycle using a Bose-Einstein condensate (BEC) with nonlinear interactions as the working medium. Exploiting Feshbach resonances to change the interaction strength of the BEC allows us to produce work by expanding and compressing the gas. To ensure a large power output from this engine these strokes must be performed on a short timescale, however such non-adiabatic strokes can create irreversible work which degrades the engine’s efficiency. To combat this, we design a shortcut to adiabaticity which can achieve an adiabatic-like evolution within a finite time, therefore significantly reducing the out-of-equilibrium excitations in the BEC. We investigate the effect of the shortcut to adiabaticity on the efficiency and power output of the engine and show that the tunable nonlinearity strength, modulated by Feshbach resonances, serves as a useful tool to enhance the system’s performance.

  18. Wave Propagation in Linear and Nonlinear Photonic Band-Gap Materials

    National Research Council Canada - National Science Library

    Venakides, Stephanos

    2003-01-01

    .... Development of 3D boundary element code for EM scattering off photonic crystal slabs. Development of 2D FDTD code that includes nonlinearities and use in studying resonant phenomena. Nonlinear Effects...

  19. Zigzag phosphorene nanoribbons: one-dimensional resonant channels in two-dimensional atomic crystals

    Science.gov (United States)

    Páez, Carlos J; Pereira, Ana L C; Schulz, Peter A

    2016-01-01

    We theoretically investigate phosphorene zigzag nanoribbons as a platform for constriction engineering. In the presence of a constriction at one of the edges, quantum confinement of edge-protected states reveals conductance peaks, if the edge is uncoupled from the other edge. If the constriction is narrow enough to promote coupling between edges, it gives rise to Fano-like resonances as well as antiresonances in the transmission spectrum. These effects are shown to mimic an atomic chain like behavior in a two dimensional atomic crystal. PMID:28144546

  20. Zigzag phosphorene nanoribbons: one-dimensional resonant channels in two-dimensional atomic crystals

    Directory of Open Access Journals (Sweden)

    Carlos. J. Páez

    2016-12-01

    Full Text Available We theoretically investigate phosphorene zigzag nanoribbons as a platform for constriction engineering. In the presence of a constriction at one of the edges, quantum confinement of edge-protected states reveals conductance peaks, if the edge is uncoupled from the other edge. If the constriction is narrow enough to promote coupling between edges, it gives rise to Fano-like resonances as well as antiresonances in the transmission spectrum. These effects are shown to mimic an atomic chain like behavior in a two dimensional atomic crystal.

  1. Gradient-based optimization in nonlinear structural dynamics

    DEFF Research Database (Denmark)

    Dou, Suguang

    The intrinsic nonlinearity of mechanical structures can give rise to rich nonlinear dynamics. Recently, nonlinear dynamics of micro-mechanical structures have contributed to developing new Micro-Electro-Mechanical Systems (MEMS), for example, atomic force microscope, passive frequency divider......, frequency stabilization, and disk resonator gyroscope. For advanced design of these structures, it is of considerable value to extend current optimization in linear structural dynamics into nonlinear structural dynamics. In this thesis, we present a framework for modelling, analysis, characterization......, and optimization of nonlinear structural dynamics. In the modelling, nonlinear finite elements are used. In the analysis, nonlinear frequency response and nonlinear normal modes are calculated based on a harmonic balance method with higher-order harmonics. In the characterization, nonlinear modal coupling...

  2. Nonlinear Elliptic Differential Equations with Multivalued Nonlinearities

    Indian Academy of Sciences (India)

    In this paper we study nonlinear elliptic boundary value problems with monotone and nonmonotone multivalued nonlinearities. First we consider the case of monotone nonlinearities. In the first result we assume that the multivalued nonlinearity is defined on all R R . Assuming the existence of an upper and of a lower ...

  3. Light-controlled microwave whispering-gallery-mode quasi-optical resonators at 50W LED array illumination

    Directory of Open Access Journals (Sweden)

    V. B. Yurchenko

    2015-08-01

    Full Text Available We present experimental observations of light-controlled resonance effects in microwave whispering-gallery-mode quasi-optical dielectric-semiconductor disk resonators in the frequency band of 5 GHz to 20 GHz arising due to illumination from a light emitting diode (LED of 50W power range. We obtain huge enhancement of photo-sensitivity (growing with the resonator Q-factor that makes light-microwave interaction observable with an ordinary light (no laser at conventional brightness (like an office lighting in quasi-optical microwave structures at rather long (centimeter-scale wavelength. We also demonstrate non-conventional photo-response of Fano resonances when the light suppresses one group of resonances and enhances another group. The effects could be used for the optical control and quasi-optical switching of microwave propagation through either one or another frequency channel.

  4. Averaging for solitons with nonlinearity management

    International Nuclear Information System (INIS)

    Pelinovsky, D.E.; Kevrekidis, P.G.; Frantzeskakis, D.J.

    2003-01-01

    We develop an averaging method for solitons of the nonlinear Schroedinger equation with a periodically varying nonlinearity coefficient, which is used to effectively describe solitons in Bose-Einstein condensates, in the context of the recently proposed technique of Feshbach resonance management. Using the derived local averaged equation, we study matter-wave bright and dark solitons and demonstrate a very good agreement between solutions of the averaged and full equations

  5. Electrothermal Frequency Modulated Resonator for Mechanical Memory

    KAUST Repository

    Hafiz, Md Abdullah Al; Kosuru, Lakshmoji; Younis, Mohammad I.

    2016-01-01

    In this paper, we experimentally demonstrate a mechanical memory device based on the nonlinear dynamics of an electrostatically actuated microelectromechanical resonator utilizing an electrothermal frequency modulation scheme. The microstructure

  6. Design of a nonlinear torsional vibration absorber

    Science.gov (United States)

    Tahir, Ammaar Bin

    Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is usually tuned for a specific resonant frequency or an operating frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies, or for a system with varying excitation frequency. Vibration dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. In this study, an experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber with geometrically induced cubic stiffness nonlinearity. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, the design optimization of the nonlinear torsional vibration absorber was carried out using an equivalent 2-DOF modal model. The optimality criterion was chosen to be maximization of energy dissipation in the nonlinear absorber attached to the equivalent 2-DOF system. The optimized design parameters of the nonlinear absorber were tested on the original 5-DOF system numerically. A comparison was made between the performance of linear and nonlinear absorbers using the numerical models. The comparison showed the superiority of the nonlinear absorber over its linear counterpart for the given set of primary system parameters as the vibration energy dissipation in the former is

  7. Resonance line shape, strain and electric potential distributions of composite magnetoelectric sensors

    Directory of Open Access Journals (Sweden)

    Martina Gerken

    2013-06-01

    shape and a zero-response frequency result for the ME coefficient. The zero-response oscillator frequency may be below or above the resonance frequency. The calculated FEM resonance line shapes are fitted successfully to a superposition function of a constant component and a resonant component with a Lorentzian line shape. Equivalence of the superposition function line shape to a Fano resonance profile is derived for frequencies around the resonance. Fano resonances are ubiquitous in physics occurring due to the constructive and destructive quantum interference of two different scattering pathways, e.g., for photons or electrons. The superposition fit parameters describing the resonance line shape are calculated as a function of the cantilever substrate thickness. The inclusion of loss by adjustment of the damping parameter is discussed. The results derived here also are applicable to higher order modes or longitudinal resonance modes.

  8. Nonlinear Electromagnetic Stabilization of Plasma Microturbulence

    Science.gov (United States)

    Whelan, G. G.; Pueschel, M. J.; Terry, P. W.

    2018-04-01

    The physical causes for the strong stabilizing effect of finite plasma β on ion-temperature-gradient-driven turbulence, which far exceeds quasilinear estimates, are identified from nonlinear gyrokinetic simulations. The primary contribution stems from a resonance of frequencies in the dominant nonlinear interaction between the unstable mode, the stable mode, and zonal flows, which maximizes the triplet correlation time and therefore the energy transfer efficiency. A modification to mixing-length transport estimates is constructed, which reproduces nonlinear heat fluxes throughout the examined β range.

  9. Enhanced Nonlinear Effects in Metamaterials and Plasmonics

    Directory of Open Access Journals (Sweden)

    C. Argyropoulos

    2012-07-01

    Full Text Available In this paper we provide an overview of the anomalous and enhanced nonlinear effects available when optical nonlinear materials are combined inside plasmonic waveguide structures. Broad, bistable and all-optical switching responses are exhibited at the cut-off frequency of these waveguides, characterized by reduced Q-factor resonances. These phenomena are due to the large field enhancement obtained inside specific plasmonic gratings, which ensures a significant boosting of the nonlinear operation. Several exciting applications are proposed, which may potentially lead to new optical components and add to the optical nanocircuit paradigm.

  10. Chromatic perturbation and resonance analysis for the AGS-Booster

    International Nuclear Information System (INIS)

    Parsa, Z.

    1987-01-01

    The authors investigated the nonlinear effects with the emphasis on nonlinear resonances. They present some of their findings, (e.g. the structure resonances; stop-bandwidths, etc.) for the AGS-Booster Lattice using program HARMON. Comparison with the results obtained from the algorithm ''NONLIN'' is presented

  11. Nonlinear dynamics experiment in the Tevatron

    International Nuclear Information System (INIS)

    Merminga, N.; Edwards, D.; Finley, D.

    1989-01-01

    Results of the continuing analysis of the nonlinear dynamics experiment E778 are presented. Sixteen special sextupoles introduced nonlinearities in the Tevatron. 'Smear,' which is one of the parameters used to quantify the degree of nonlinearity, was extracted from the data and compared with calculation. Injection efficiency in the presence of nonlinearities was studied. Measurements of the dynamic aperture were performed. The final results in one degree of freedom of the smear, the injection efficiency and the dynamic aperture are presented. Particles captured on nonlinear resonance islands were directly observed and measurements were performed. The capture efficiency was extracted from the data and compared with prediction. The influence of tune modulation on the stability of these islands was investigated. Plans for future measurements are discussed. 4 refs., 6 figs

  12. Discontinuity and complexity in nonlinear physical systems

    CERN Document Server

    Baleanu, Dumitru; Luo, Albert

    2014-01-01

    This unique book explores recent developments in experimental research in this broad field, organized in four distinct sections. Part I introduces the reader to the fractional dynamics and Lie group analysis for nonlinear partial differential equations. Part II covers chaos and complexity in nonlinear Hamiltonian systems, important to understand the resonance interactions in nonlinear dynamical systems, such as Tsunami waves and wildfire propagations; as well as Lev flights in chaotic trajectories, dynamical system synchronization and DNA information complexity analysis. Part III examines chaos and periodic motions in discontinuous dynamical systems, extensively present in a range of systems, including piecewise linear systems, vibro-impact systems and drilling systems in engineering. And in Part IV, engineering and financial nonlinearity are discussed. The mechanism of shock wave with saddle-node bifurcation and rotating disk stability will be presented, and the financial nonlinear models will be discussed....

  13. Theory and design of nonlinear metamaterials

    Science.gov (United States)

    Rose, Alec Daniel

    and oscillators. By applying this set of tools and knowledge to microwave metamaterials, I experimentally confirm several novel nonlinear phenomena. Most notably, I construct a backward wave nonlinear medium from varactor-loaded split ring resonators loaded in a rectangular waveguide, capable of generating second-harmonic opposite to conventional nonlinear materials with a conversion efficiency as high as 1.5%. In addition, I confirm nonlinear magnetoelectric coupling in two dual gap varactor-loaded split ring resonator metamaterials through measurement of the amplitude and phase of the second-harmonic generated in the forward and backward directions from a thin slab. I then use the presence of simultaneous nonlinearities in such metamaterials to observe nonlinear interference, manifest as unidirectional difference frequency generation with contrasts of 6 and 12 dB in the forward and backward directions, respectively. Finally, I apply these principles and intuition to several plasmonic platforms with the goal of achieving similar enhancements and configurations at optical frequencies. Using the example of fluorescence enhancement in optical patch antennas, I develop a semi-classical numerical model for the calculation of field-induced enhancements to both excitation and spontaneous emission rates of an embedded fluorophore, showing qualitative agreement with experimental results, with enhancement factors of more than 30,000. Throughout these series of works, I emphasize the indispensability of effective design and retrieval tools in understanding and optimizing both metamaterials and plasmonic systems. Ultimately, when weighed against the disadvantages in fabrication and optical losses, the results presented here provide a context for the application of nonlinear metamaterials within three distinct areas where a competitive advantage over conventional materials might be obtained: fundamental science demonstrations, linear and nonlinear anisotropy engineering, and

  14. Nonlinear Elasticity

    Science.gov (United States)

    Fu, Y. B.; Ogden, R. W.

    2001-05-01

    This collection of papers by leading researchers in the field of finite, nonlinear elasticity concerns itself with the behavior of objects that deform when external forces or temperature gradients are applied. This process is extremely important in many industrial settings, such as aerospace and rubber industries. This book covers the various aspects of the subject comprehensively with careful explanations of the basic theories and individual chapters each covering a different research direction. The authors discuss the use of symbolic manipulation software as well as computer algorithm issues. The emphasis is placed firmly on covering modern, recent developments, rather than the very theoretical approach often found. The book will be an excellent reference for both beginners and specialists in engineering, applied mathematics and physics.

  15. Overview of magnetic nonlinear beam dynamics in the RHIC

    International Nuclear Information System (INIS)

    Luo, Y.; Bai, M.; Beebe-Wang, J.; Bengtsson, J.; Calaga, R.; Fischer, W.; Jain, A.; Pilat, F.; Ptitsyn, V.; Malitsky, N.; Robert-Demolaize, G.; Satogata, T.; Tepikian, S.; Tomas, R.; Trbojevic, D.

    2009-01-01

    In this article we review our studies of nonlinear beam dynamics due to the nonlinear magnetic field errors in the Relativistic Heavy Ion Collider (RHIC). Nonlinear magnetic field errors, including magnetic field errors in interaction regions (IRs), chromatic sextupoles, and sextupole components from arc main dipoles are discussed. Their effects on beam dynamics and beam dynamic aperture are evaluated. The online methods to measure and correct the IR nonlinear field errors, second order chromaticities, and horizontal third order resonance are presented. The overall strategy for nonlinear corrections in RHIC is discussed

  16. Quantum multiple scattering: Eigenmode expansion and its applications to proximity resonance

    International Nuclear Information System (INIS)

    Li Sheng; Heller, Eric J.

    2003-01-01

    We show that for a general system of N s-wave point scatterers, there are always N eigenmodes. These eigenmodes or eigenchannels play the same role as spherical harmonics for a spherically symmetric target--they give a phase shift only. In other words, the T matrix of the system is of rank N, and the eigenmodes are eigenvectors corresponding to nonzero eigenvalues of the T matrix. The eigenmode expansion approach can give insight to the total scattering cross section; the position, width, and superradiant or subradiant nature of resonance peaks; the unsymmetric Fano line shape of sharp proximity resonance peaks based on the high-energy tail of a broadband; and other properties. Off-resonant eigenmodes for identical proximate scatterers are approximately angular-momentum eigenstates

  17. Nonlinear interaction of waves in an inhomogeneous plasma

    International Nuclear Information System (INIS)

    Istomin, Ya.N.

    1988-01-01

    Nonlinear wave processes in a weakly inhomogeneous plasma are considered. A quasilinear equation is derived which takes into account the effect of the waves on resonance particles, provided that the inhomogeneity appreciably affects the nature of the resonance interaction. Three-wave interaction is investigated under the same conditions. As an example, the nonlinear interaction in a relativistic plasma moving along a strong curvilinear magnetic field is considered

  18. Efecto de la ingesta de cereales enriquecidos con triptófano sobre el sueño, melatonina, serotonina, cortisol y estado antioxidante en personas mayores

    OpenAIRE

    Matito Celaya, Sergio

    2015-01-01

    Teniendo en cuenta el concepto de Crononutrición y la secreción de melatonina, serotonina, cortisol durante el día y la noche, nuestro objetivo ha sido analizar como el consumo de cereales enriquecidos con triptófano, precursor de Serotonina y Melatonina, puede ayudar a la reestructuración del ciclo sueño / vigilia, como actúa sobre la secreción de Cortisol matutino y como la Melatonina ayuda a la excreción de radicales libres en orina por su capacidad antioxidante. Para objetivar como afec...

  19. Nonlinear propagation of the extraordinary mode in a hot magnetoplasma

    International Nuclear Information System (INIS)

    Khiet, Tu; Furutani, Y.; Ichikawa, Y.H.

    1978-07-01

    Kinetic theory for a nonlinear propagation of quasi-monochromatic extraordinary waves is presented. It reveals that propagation of an envelope of the extraordinary carriers is described by the nonlinear Schroedinger equation. In a cold plasma limit, a detailed analysis is carried out on a behaviour of the envelope of the upper- and the lower-hybrid waves at respective resonant frequency ranges. (author)

  20. Semiclassical theory of resonance inelastic electron-molecule collisions

    International Nuclear Information System (INIS)

    Kazanskij, A.K.

    1986-01-01

    Semiclassical approach to the theory of resonance electron-molecule collisions, unlocal with respect to interatomic distance was developed. Two problems were considered: modified adiabatic approach for sigle-pole approximation of R-matrix and Fano-Feshbach-Bardsley theory. It is shown that these problems are similar in semiclassical approximation. A simple equation system with coefficients expressed in quadratures was obtained. It enables to determine amplitudes of all processes (including dissociation adhesion, association ejection, free-free and free-bound transitions) in energetic representation with respect to nucleus vibrations in molecule with allowance for both descrete and continuous spectra of nucleus motion in molecule. Quantitative investigation of the system results to the notion of dynamic energy curve of intermediate state, generalizing the motion of such curve in boomerang theory

  1. [Nonlinear magnetohydrodynamics

    International Nuclear Information System (INIS)

    1994-01-01

    Resistive MHD equilibrium, even for small resistivity, differs greatly from ideal equilibrium, as do the dynamical consequences of its instabilities. The requirement, imposed by Faraday's law, that time independent magnetic fields imply curl-free electric fields, greatly restricts the electric fields allowed inside a finite-resistivity plasma. If there is no flow and the implications of the Ohm's law are taken into account (and they need not be, for ideal equilibria), the electric field must equal the resistivity times the current density. The vanishing of the divergence of the current density then provides a partial differential equation which, together with boundary conditions, uniquely determines the scalar potential, the electric field, and the current density, for any given resistivity profile. The situation parallels closely that of driven shear flows in hydrodynamics, in that while dissipative steady states are somewhat more complex than ideal ones, there are vastly fewer of them to consider. Seen in this light, the vast majority of ideal MHD equilibria are just irrelevant, incapable of being set up in the first place. The steady state whose stability thresholds and nonlinear behavior needs to be investigated ceases to be an arbitrary ad hoc exercise dependent upon the whim of the investigator, but is determined by boundary conditions and choice of resistivity profile

  2. Stochastic resonance

    International Nuclear Information System (INIS)

    Wellens, Thomas; Shatokhin, Vyacheslav; Buchleitner, Andreas

    2004-01-01

    We are taught by conventional wisdom that the transmission and detection of signals is hindered by noise. However, during the last two decades, the paradigm of stochastic resonance (SR) proved this assertion wrong: indeed, addition of the appropriate amount of noise can boost a signal and hence facilitate its detection in a noisy environment. Due to its simplicity and robustness, SR has been implemented by mother nature on almost every scale, thus attracting interdisciplinary interest from physicists, geologists, engineers, biologists and medical doctors, who nowadays use it as an instrument for their specific purposes. At the present time, there exist a lot of diversified models of SR. Taking into account the progress achieved in both theoretical understanding and practical application of this phenomenon, we put the focus of the present review not on discussing in depth technical details of different models and approaches but rather on presenting a general and clear physical picture of SR on a pedagogical level. Particular emphasis will be given to the implementation of SR in generic quantum systems-an issue that has received limited attention in earlier review papers on the topic. The major part of our presentation relies on the two-state model of SR (or on simple variants thereof), which is general enough to exhibit the main features of SR and, in fact, covers many (if not most) of the examples of SR published so far. In order to highlight the diversity of the two-state model, we shall discuss several examples from such different fields as condensed matter, nonlinear and quantum optics and biophysics. Finally, we also discuss some situations that go beyond the generic SR scenario but are still characterized by a constructive role of noise

  3. Nonlinear Faraday rotation in samarium vapor

    International Nuclear Information System (INIS)

    Barkov, L.M.; Melik-Pashaev, D.A.; Zolotorev, M.S.

    1988-01-01

    Experiments on nonlinear magnetic optical (Faraday) rotation on resonance transitions of atomic samarium are described. Measurements were carried out on transitions with different angular momenta of upper and lower states: 1→0, 0→1 and 1→1. Qualitative explanations of observed phenomena are given

  4. Nonlinear extraordinary wave in dense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Krasovitskiy, V. B., E-mail: krasovit@mail.ru [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation); Turikov, V. A. [Russian University of Peoples’ Friendship (Russian Federation)

    2013-10-15

    Conditions for the propagation of a slow extraordinary wave in dense magnetized plasma are found. A solution to the set of relativistic hydrodynamic equations and Maxwell’s equations under the plasma resonance conditions, when the phase velocity of the nonlinear wave is equal to the speed of light, is obtained. The deviation of the wave frequency from the resonance frequency is accompanied by nonlinear longitudinal-transverse oscillations. It is shown that, in this case, the solution to the set of self-consistent equations obtained by averaging the initial equations over the period of high-frequency oscillations has the form of an envelope soliton. The possibility of excitation of a nonlinear wave in plasma by an external electromagnetic pulse is confirmed by numerical simulations.

  5. Oscillating nonlinear acoustic shock waves

    DEFF Research Database (Denmark)

    Gaididei, Yuri; Rasmussen, Anders Rønne; Christiansen, Peter Leth

    2016-01-01

    We investigate oscillating shock waves in a tube using a higher order weakly nonlinear acoustic model. The model includes thermoviscous effects and is non isentropic. The oscillating shock waves are generated at one end of the tube by a sinusoidal driver. Numerical simulations show that at resona......We investigate oscillating shock waves in a tube using a higher order weakly nonlinear acoustic model. The model includes thermoviscous effects and is non isentropic. The oscillating shock waves are generated at one end of the tube by a sinusoidal driver. Numerical simulations show...... polynomial in the space and time variables, we find analytical approximations to the observed single shock waves in an infinitely long tube. Using perturbation theory for the driven acoustic system approximative analytical solutions for the off resonant case are determined....

  6. New approaches to nonlinear waves

    CERN Document Server

    2016-01-01

    The book details a few of the novel methods developed in the last few years for studying various aspects of nonlinear wave systems. The introductory chapter provides a general overview, thematically linking the objects described in the book. Two chapters are devoted to wave systems possessing resonances with linear frequencies (Chapter 2) and with nonlinear frequencies (Chapter 3). In the next two chapters modulation instability in the KdV-type of equations is studied using rigorous mathematical methods (Chapter 4) and its possible connection to freak waves is investigated (Chapter 5). The book goes on to demonstrate how the choice of the Hamiltonian (Chapter 6) or the Lagrangian (Chapter 7) framework allows us to gain a deeper insight into the properties of a specific wave system. The final chapter discusses problems encountered when attempting to verify the theoretical predictions using numerical or laboratory experiments. All the chapters are illustrated by ample constructive examples demonstrating the app...

  7. Nonlinear waves and pattern dynamics

    CERN Document Server

    Pelinovsky, Efim; Mutabazi, Innocent

    2018-01-01

    This book addresses the fascinating phenomena associated with nonlinear waves and spatio-temporal patterns. These appear almost everywhere in nature from sand bed forms to brain patterns, and yet their understanding still presents fundamental scientific challenges. The reader will learn here, in particular, about the current state-of-the art and new results in: Nonlinear water waves: resonance, solitons, focusing, Bose-Einstein condensation, as well as and their relevance for the sea environment (sea-wind interaction, sand bed forms, fiber clustering) Pattern formation in non-equilibrium media: soap films, chimera patterns in oscillating media, viscoelastic Couette-Taylor flow, flow in the wake behind a heated cylinder, other pattern formation. The editors and authors dedicate this book to the memory of Alexander Ezersky, Professor of Fluid Mechanics at the University of Caen Normandie (France) from September 2007 to July 2016. Before 2007, he had served as a Senior Scientist at the Institute of Applied Physi...

  8. A programmable nonlinear acoustic metamaterial

    Directory of Open Access Journals (Sweden)

    Tianzhi Yang

    2017-09-01

    Full Text Available Acoustic metamaterials with specifically designed lattices can manipulate acoustic/elastic waves in unprecedented ways. Whereas there are many studies that focus on passive linear lattice, with non-reconfigurable structures. In this letter, we present the design, theory and experimental demonstration of an active nonlinear acoustic metamaterial, the dynamic properties of which can be modified instantaneously with reversibility. By incorporating active and nonlinear elements in a single unit cell, a real-time tunability and switchability of the band gap is achieved. In addition, we demonstrate a dynamic “editing” capability for shaping transmission spectra, which can be used to create the desired band gap and resonance. This feature is impossible to achieve in passive metamaterials. These advantages demonstrate the versatility of the proposed device, paving the way toward smart acoustic devices, such as logic elements, diode and transistor.

  9. Humanización de la Atención de Enfermería en el Quirófano Humanization of caring: Nursing at Surgical Center

    Directory of Open Access Journals (Sweden)

    Carolina Heluy de Castro

    2004-06-01

    Full Text Available En el quirófano, muchas veces, la atención al paciente es impersonal y, naturalmente, los problemas individuales son ignorados. El estudio pretende identificar lo que representa la humanización para los profesionales y su relación con la satisfacción del paciente de este quirófano, a través del contacto directo con ellos. Probablemente, una atención humanizada es el primer paso para alcanzar el éxito y la calidad asistencial en los servicios de salud.Often, in surgical center, patient´s attendance is impersonal and, naturally, peculiar problems are unawarred. The aim of this study is to recognize professionals and their relationship with patients´satisfaction representing around humanization, an in-depth direct contact with sanitary staff and patients at those operating rooms. Probably, a humanization of caring is the first steep to reach success and quality of attendance in the health services.

  10. Nonlinear beam mechanics

    NARCIS (Netherlands)

    Westra, H.J.R.

    2012-01-01

    In this Thesis, nonlinear dynamics and nonlinear interactions are studied from a micromechanical point of view. Single and doubly clamped beams are used as model systems where nonlinearity plays an important role. The nonlinearity also gives rise to rich dynamic behavior with phenomena like

  11. Electrothermally Tunable Arch Resonator

    KAUST Repository

    Hajjaj, Amal Z.

    2017-03-18

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of electrothermally actuated microelectromechanical arch beams. The beams are made of silicon and are intentionally fabricated with some curvature as in-plane shallow arches. An electrothermal voltage is applied between the anchors of the beam generating a current that controls the axial stress caused by thermal expansion. When the electrothermal voltage increases, the compressive stress increases inside the arch beam. This leads to an increase in its curvature, thereby increasing its resonance frequencies. We show here that the first resonance frequency can increase monotonically up to twice its initial value. We show also that after some electrothermal voltage load, the third resonance frequency starts to become more sensitive to the axial thermal stress, while the first resonance frequency becomes less sensitive. These results can be used as guidelines to utilize arches as wide-range tunable resonators. Analytical results based on the nonlinear Euler Bernoulli beam theory are generated and compared with the experimental data and the results of a multi-physics finite-element model. A good agreement is found among all the results. [2016-0291

  12. Nonlinear optical studies in semiconductor-doped glasses under ...

    Indian Academy of Sciences (India)

    Abstract. Nonlinear optical studies in semiconductor-doped glasses (SDGs) are per- formed under femtosecond laser pulse excitation. Z-scan experiments with 800 nm wave- length pulses are used to excite SDG samples in the resonance and non-resonance regimes. Schott colour glass filter OG 515 shows stronger ...

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

    Science.gov (United States)

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

    2018-01-01

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

  14. Manipulating acoustic wave reflection by a nonlinear elastic metasurface

    Science.gov (United States)

    Guo, Xinxin; Gusev, Vitalyi E.; Bertoldi, Katia; Tournat, Vincent

    2018-03-01

    The acoustic wave reflection properties of a nonlinear elastic metasurface, derived from resonant nonlinear elastic elements, are theoretically and numerically studied. The metasurface is composed of a two degree-of-freedom mass-spring system with quadratic elastic nonlinearity. The possibility of converting, during the reflection process, most of the fundamental incoming wave energy into the second harmonic wave is shown, both theoretically and numerically, by means of a proper design of the nonlinear metasurface. The theoretical results from the harmonic balance method for a monochromatic source are compared with time domain simulations for a wave packet source. This protocol allows analyzing the dynamics of the nonlinear reflection process in the metasurface as well as exploring the limits of the operating frequency bandwidth. The reported methodology can be applied to a wide variety of nonlinear metasurfaces, thus possibly extending the family of exotic nonlinear reflection processes.

  15. Multiphoton resonances

    International Nuclear Information System (INIS)

    Shore, B.W.

    1977-01-01

    The long-time average of level populations in a coherently-excited anharmonic sequence of energy levels (e.g., an anharmonic oscillator) exhibits sharp resonances as a function of laser frequency. For simple linearly-increasing anharmonicity, each resonance is a superposition of various multiphoton resonances (e.g., a superposition of 3, 5, 7, . . . photon resonances), each having its own characteristic width predictable from perturbation theory

  16. NONLINEAR TIDES IN CLOSE BINARY SYSTEMS

    International Nuclear Information System (INIS)

    Weinberg, Nevin N.; Arras, Phil; Quataert, Eliot; Burkart, Josh

    2012-01-01

    We study the excitation and damping of tides in close binary systems, accounting for the leading-order nonlinear corrections to linear tidal theory. These nonlinear corrections include two distinct physical effects: three-mode nonlinear interactions, i.e., the redistribution of energy among stellar modes of oscillation, and nonlinear excitation of stellar normal modes by the time-varying gravitational potential of the companion. This paper, the first in a series, presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism we present is applicable to binaries containing stars, planets, and/or compact objects, we focus on non-rotating solar-type stars with stellar or planetary companions. Our primary results include the following: (1) The linear tidal solution almost universally used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited internal gravity waves in solar-type stars are nonlinearly unstable to parametric resonance for companion masses M' ∼> 10-100 M ⊕ at orbital periods P ≈ 1-10 days. The nearly static 'equilibrium' tidal distortion is, however, stable to parametric resonance except for solar binaries with P ∼ 3 [P/10 days] for a solar-type star) and drives them as a single coherent unit with growth rates that are a factor of ≈N faster than the standard three-wave parametric instability. These are local instabilities viewed through the lens of global analysis; the coherent global growth rate follows local rates in the regions where the shear is strongest. In solar-type stars, the dynamical tide is unstable to this collective version of the parametric instability for even sub-Jupiter companion masses with P ∼< a month. (4) Independent of the parametric instability, the dynamical and equilibrium tides excite a wide range of stellar p-modes and g-modes by nonlinear inhomogeneous forcing

  17. Superconducting Nanowires as Nonlinear Inductive Elements for Qubits

    OpenAIRE

    Ku, Jaseung; Manucharyan, Vladimir; Bezryadin, Alexey

    2010-01-01

    We report microwave transmission measurements of superconducting Fabry-Perot resonators (SFPR), having a superconducting nanowire placed at a supercurrent antinode. As the plasma oscillation is excited, the supercurrent is forced to flow through the nanowire. The microwave transmission of the resonator-nanowire device shows a nonlinear resonance behavior, significantly dependent on the amplitude of the supercurrent oscillation. We show that such amplitude-dependent response is due to the nonl...

  18. Nonlinear response and bistability of driven ion acoustic waves

    Science.gov (United States)

    Akbari-Moghanjoughi, M.

    2017-08-01

    The hydrodynamic model is used to obtain a generalized pseudoforce equation through which the nonlinear response of periodically driven ion acoustic waves is studied in an electron-ion plasma with isothermal and adiabatic ion fluids. The pseudotime series, corresponding to different driving frequencies, indicates that nonlinearity effects appear more strongly for smaller frequency values. The existence of extra harmonic resonances in the nonlinear amplitude spectrum is a clear indication of the interaction of an external force with harmonic components of the nonlinear ion acoustic waves. It is shown that many plasma parameters significantly and differently affect the nonlinear resonance spectrum of ion acoustic excitations. A heuristic but accurate model for the foldover effect is used which quite satisfactorily predicts the bistability of driven plasma oscillations. It is remarked that the characteristic resonance peak of isothermal ion plasma oscillations appears at lower frequencies but is stronger compared to that of adiabatic ions. Comparison of the exact numerical results for fully nonlinear and approximate (weakly nonlinear) models indicates that a weakly nonlinear model exaggerates the hysteresis and jump phenomenon for higher values of the external force amplitude.

  19. The importance of non-linearities in modern proton synchrotrons

    International Nuclear Information System (INIS)

    Wilson, E.J.N.

    1977-01-01

    The paper outlines the physics and mathematics of non-linear field errors in the quide fields of accelerators, with particular reference to large accelerators such as the SPS. These non-linearities give rise to closed orbital distortions and non-linear resonances or stopbands. Both of these effects are briefly discussed and the use of resonances for slow beam extraction is also described. Another problem considered is that of chromaticity of the particle beam. The use of sextupoles to correct chromaticity and the Landau damping of beam instabilities using octupoles are also discussed. In the final section the application of Hamiltonian mechanics to non-linearities is demonstrated. The author concludes that the effect of non-linearities on particle dynamics may place a more severe limit on intensity and storage time in large rings than any other effect in transverse phase space. (B.D.)

  20. Nonlinear switching dynamics in a photonic-crystal nanocavity

    International Nuclear Information System (INIS)

    Yu, Yi; Palushani, Evarist; Heuck, Mikkel; Vukovic, Dragana; Peucheret, Christophe; Yvind, Kresten; Mork, Jesper

    2014-01-01

    We report the experimental observation of nonlinear switching dynamics in an InP photonic crystal nanocavity. Usually, the regime of relatively small cavity perturbations is explored, where the signal transmitted through the cavity follows the temporal variation of the cavity resonance. When the cavity is perturbed by strong pulses, we observe several nonlinear effects, i.e., saturation of the switching contrast, broadening of the switching window, and even initial reduction of the transmission. The effects are analyzed by comparison with nonlinear coupled mode theory and explained in terms of large dynamical variations of the cavity resonance in combination with nonlinear losses. The results provide insight into the nonlinear optical processes that govern the dynamics of nanocavities and are important for applications in optical signal processing, where one wants to optimize the switching contrast.

  1. Nonlinear switching dynamics in a photonic-crystal nanocavity

    DEFF Research Database (Denmark)

    Yu, Yi; Palushani, Evarist; Heuck, Mikkel

    2014-01-01

    We report the experimental observation of nonlinear switching dynamics in an InP photonic crystal nanocavity. Usually, the regime of relatively small cavity perturbations is explored, where the signal transmitted through the cavity follows the temporal variation of the cavity resonance. When...... of large dynamical variations of the cavity resonance in combination with nonlinear losses. The results provide insight into the nonlinear optical processes that govern the dynamics of nanocavities and are important for applications in optical signal processing, where one wants to optimize the switching...... the cavity is perturbed by strong pulses, we observe several nonlinear effects, i.e., saturation of the switching contrast, broadening of the switching window, and even initial reduction of the transmission. The effects are analyzed by comparison with nonlinear coupled mode theory and explained in terms...

  2. Applications of Nonlinear Dynamics Model and Design of Complex Systems

    CERN Document Server

    In, Visarath; Palacios, Antonio

    2009-01-01

    This edited book is aimed at interdisciplinary, device-oriented, applications of nonlinear science theory and methods in complex systems. In particular, applications directed to nonlinear phenomena with space and time characteristics. Examples include: complex networks of magnetic sensor systems, coupled nano-mechanical oscillators, nano-detectors, microscale devices, stochastic resonance in multi-dimensional chaotic systems, biosensors, and stochastic signal quantization. "applications of nonlinear dynamics: model and design of complex systems" brings together the work of scientists and engineers that are applying ideas and methods from nonlinear dynamics to design and fabricate complex systems.

  3. SU-E-T-180: Fano Cavity Test of Proton Transport in Monte Carlo Codes Running On GPU and Xeon Phi

    International Nuclear Information System (INIS)

    Sterpin, E; Sorriaux, J; Souris, K; Lee, J; Vynckier, S; Schuemann, J; Paganetti, H; Jia, X; Jiang, S

    2014-01-01

    Purpose: In proton dose calculation, clinically compatible speeds are now achieved with Monte Carlo codes (MC) that combine 1) adequate simplifications in the physics of transport and 2) the use of hardware architectures enabling massive parallel computing (like GPUs). However, the uncertainties related to the transport algorithms used in these codes must be kept minimal. Such algorithms can be checked with the so-called “Fano cavity test”. We implemented the test in two codes that run on specific hardware: gPMC on an nVidia GPU and MCsquare on an Intel Xeon Phi (60 cores). Methods: gPMC and MCsquare are designed for transporting protons in CT geometries. Both codes use the method of fictitious interaction to sample the step-length for each transport step. The considered geometry is a water cavity (2×2×0.2 cm 3 , 0.001 g/cm 3 ) in a 10×10×50 cm 3 water phantom (1 g/cm 3 ). CPE in the cavity is established by generating protons over the phantom volume with a uniform momentum (energy E) and a uniform intensity per unit mass I. Assuming no nuclear reactions and no generation of other secondaries, the computed cavity dose should equal IE, according to Fano's theorem. Both codes were tested for initial proton energies of 50, 100, and 200 MeV. Results: For all energies, gPMC and MCsquare are within 0.3 and 0.2 % of the theoretical value IE, respectively (0.1% standard deviation). Single-precision computations (instead of double) increased the error by about 0.1% in MCsquare. Conclusion: Despite the simplifications in the physics of transport, both gPMC and MCsquare successfully pass the Fano test. This ensures optimal accuracy of the codes for clinical applications within the uncertainties on the underlying physical models. It also opens the path to other applications of these codes, like the simulation of ion chamber response

  4. SU-E-T-180: Fano Cavity Test of Proton Transport in Monte Carlo Codes Running On GPU and Xeon Phi

    Energy Technology Data Exchange (ETDEWEB)

    Sterpin, E; Sorriaux, J; Souris, K; Lee, J; Vynckier, S [Universite catholique de Louvain, Brussels, Brussels (Belgium); Schuemann, J; Paganetti, H [Massachusetts General Hospital, Boston, MA (United States); Jia, X; Jiang, S [The University of Texas Southwestern Medical Ctr, Dallas, TX (United States)

    2014-06-01

    Purpose: In proton dose calculation, clinically compatible speeds are now achieved with Monte Carlo codes (MC) that combine 1) adequate simplifications in the physics of transport and 2) the use of hardware architectures enabling massive parallel computing (like GPUs). However, the uncertainties related to the transport algorithms used in these codes must be kept minimal. Such algorithms can be checked with the so-called “Fano cavity test”. We implemented the test in two codes that run on specific hardware: gPMC on an nVidia GPU and MCsquare on an Intel Xeon Phi (60 cores). Methods: gPMC and MCsquare are designed for transporting protons in CT geometries. Both codes use the method of fictitious interaction to sample the step-length for each transport step. The considered geometry is a water cavity (2×2×0.2 cm{sup 3}, 0.001 g/cm{sup 3}) in a 10×10×50 cm{sup 3} water phantom (1 g/cm{sup 3}). CPE in the cavity is established by generating protons over the phantom volume with a uniform momentum (energy E) and a uniform intensity per unit mass I. Assuming no nuclear reactions and no generation of other secondaries, the computed cavity dose should equal IE, according to Fano's theorem. Both codes were tested for initial proton energies of 50, 100, and 200 MeV. Results: For all energies, gPMC and MCsquare are within 0.3 and 0.2 % of the theoretical value IE, respectively (0.1% standard deviation). Single-precision computations (instead of double) increased the error by about 0.1% in MCsquare. Conclusion: Despite the simplifications in the physics of transport, both gPMC and MCsquare successfully pass the Fano test. This ensures optimal accuracy of the codes for clinical applications within the uncertainties on the underlying physical models. It also opens the path to other applications of these codes, like the simulation of ion chamber response.

  5. Numerical studies of nonlinear ultrasonic guided waves in uniform waveguides with arbitrary cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Peng; Fan, Zheng, E-mail: ZFAN@ntu.edu.sg [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Zhou, Yu [Advanced Remanufacturing and Technology Center (ARTC), 3 Clean Tech Loop, CleanTech Two, Singapore 637143 (Singapore)

    2016-07-15

    Nonlinear guided waves have been investigated widely in simple geometries, such as plates, pipe and shells, where analytical solutions have been developed. This paper extends the application of nonlinear guided waves to waveguides with arbitrary cross sections. The criteria for the existence of nonlinear guided waves were summarized based on the finite deformation theory and nonlinear material properties. Numerical models were developed for the analysis of nonlinear guided waves in complex geometries, including nonlinear Semi-Analytical Finite Element (SAFE) method to identify internal resonant modes in complex waveguides, and Finite Element (FE) models to simulate the nonlinear wave propagation at resonant frequencies. Two examples, an aluminum plate and a steel rectangular bar, were studied using the proposed numerical model, demonstrating the existence of nonlinear guided waves in such structures and the energy transfer from primary to secondary modes.

  6. Nonlinear saturation controller for vibration supersession of a nonlinear composite beam

    Energy Technology Data Exchange (ETDEWEB)

    Hamed, Y. S. [Menofia University, Menouf (Egypt); Amer, Y. A. [Zagazig University, Zagazig (Egypt)

    2014-08-15

    In this paper, a study for nonlinear saturation controller (NSC) is presented that used to suppress the vibration amplitude of a structural dynamic model simulating nonlinear composite beam at simultaneous sub-harmonic and internal resonance excitation. The absorber exploits the saturation phenomenon that is known to occur in dynamical systems with quadratic non-linearities of the feedback gain and a two-to-one internal resonance. The analytical solution for the system and the nonlinear saturation controller are obtained using method of multiple time scales perturbation up to the second order approximation. All possible resonance cases were extracted at this approximation order and studied numerically. The stability of the system at the worst resonance case (Ω = 2ω{sub s} and ω{sub s} =2ω{sub C}) is investigated using both frequency response equations and phase-plane trajectories. The effects of different parameters on the system and the controller are studied numerically. The effect of some types of controller on the system is investigated numerically. The simulation results are achieved using Matlab and Maple programs.

  7. Elkarrizketa: Dani Fano

    OpenAIRE

    González Santana, Alazne

    2015-01-01

    Dani Fanori egindako elkarrizketa, Ikastolen Elkarteak argitaratzen duen Xabiroi aldizkariaren parte-hartzaileetako bat Txikitan Tintin, Asterix eta Obelix, Mortadelo y Filemón, Ipurbeltz edo Mafalda irakurtzen igarotzen zituen Dani Fanok (Donostia, 1968). Gaur egun donostiarrak Goscinny, Miguelanxo Prado, Quino, Enki Bilal, Arthur Rackham… bezalako autoreak miresten ditu. Zientzia fikzioa oso baieztatzen duen arren, denetariko komikiak irakurtzen dituela aipatzen du komiki eta irudigile g...

  8. Nonlinear Dynamics of a Diffusing Interface

    Science.gov (United States)

    Duval, Walter M. B.

    2001-01-01

    Excitation of two miscible-viscous liquids inside a bounded enclosure in a microgravity environment has shown the evolution of quasi-stationary waves of various modes for a range of parameters. We examine computationally the nonlinear dynamics of the system as the interface breakup and bifurcates to resonance structures typified by the Rayleigh-Taylor instability mechanism. Results show that when the mean steady field is much smaller than the amplitude of the sinusoidal excitation, the system behaves linearly, and growth of quasi-stationary waves occurs through the Kelvin-Helmholtz instability mechanism. However, as the amplitude of excitation increases, nonlinearity occurs through subharmonic bifurcation prior to broadband chaos.

  9. A nonlinear analysis of the EHF booster

    International Nuclear Information System (INIS)

    Colton, E.P.; Shi, D.

    1987-01-01

    We have analyzed particle motion at 1.2 GeV with assumption of nonlinearities arising from non-linear space charge forces and from the lattice sextupoles which are tuned to cancel the machine chromaticity. In the first case the motion is as expected and there are no problems as long as the x and y betatron tunes are separated by an integer or more. In the second case the motion is stable so long as the betatron amplitudes do not exceed values corresponding to beam normalized emittance of 100 mm-mr; when this occurs the effects of fifth-order betatron resonances are observed. 3 refs

  10. Nonlinear effects in water waves

    International Nuclear Information System (INIS)

    Janssen, P.A.E.M.

    1989-05-01

    This set of lecture notes on nonlinear effects in water waves was written on the occasion of the first ICTP course on Ocean Waves and Tides held from 26 September until 28 October 1988 in Trieste, Italy. It presents a summary and unification of my knowledge on nonlinear effects of gravity waves on an incompressible fluid without vorticity. The starting point of the theory is the Hamiltonian for water waves. The evolution equations of both weakly nonlinear, shallow water and deep water gravity waves are derived by suitable approximation of the energy of the waves, resulting in the Korteweg-de Vries equation and the Zakharov equation, respectively. Next, interesting properties of the KdV equation (solitons) and the Zakharov equation (instability of a finite amplitude wave train) are discussed in some detail. Finally, the evolution of a homogeneous, random wave field due to resonant four wave processes is considered and the importance of this process for ocean wave prediction is pointed out. 38 refs, 21 figs

  11. On Poisson Nonlinear Transformations

    Directory of Open Access Journals (Sweden)

    Nasir Ganikhodjaev

    2014-01-01

    Full Text Available We construct the family of Poisson nonlinear transformations defined on the countable sample space of nonnegative integers and investigate their trajectory behavior. We have proved that these nonlinear transformations are regular.

  12. Topological approximation of the nonlinear Anderson model

    Science.gov (United States)

    Milovanov, Alexander V.; Iomin, Alexander

    2014-06-01

    We study the phenomena of Anderson localization in the presence of nonlinear interaction on a lattice. A class of nonlinear Schrödinger models with arbitrary power nonlinearity is analyzed. We conceive the various regimes of behavior, depending on the topology of resonance overlap in phase space, ranging from a fully developed chaos involving Lévy flights to pseudochaotic dynamics at the onset of delocalization. It is demonstrated that the quadratic nonlinearity plays a dynamically very distinguished role in that it is the only type of power nonlinearity permitting an abrupt localization-delocalization transition with unlimited spreading already at the delocalization border. We describe this localization-delocalization transition as a percolation transition on the infinite Cayley tree (Bethe lattice). It is found in the vicinity of the criticality that the spreading of the wave field is subdiffusive in the limit t →+∞. The second moment of the associated probability distribution grows with time as a power law ∝ tα, with the exponent α =1/3 exactly. Also we find for superquadratic nonlinearity that the analog pseudochaotic regime at the edge of chaos is self-controlling in that it has feedback on the topology of the structure on which the transport processes concentrate. Then the system automatically (without tuning of parameters) develops its percolation point. We classify this type of behavior in terms of self-organized criticality dynamics in Hilbert space. For subquadratic nonlinearities, the behavior is shown to be sensitive to the details of definition of the nonlinear term. A transport model is proposed based on modified nonlinearity, using the idea of "stripes" propagating the wave process to large distances. Theoretical investigations, presented here, are the basis for consistency analysis of the different localization-delocalization patterns in systems with many coupled degrees of freedom in association with the asymptotic properties of the

  13. Real-time UV-visible spectroscopy analysis of purple membrane-polyacrylamide film formation taking into account Fano line shapes and scattering.

    Science.gov (United States)

    Gomariz, María; Blaya, Salvador; Acebal, Pablo; Carretero, Luis

    2014-01-01

    We theoretically and experimentally analyze the formation of thick Purple Membrane (PM) polyacrylamide (PA) films by means of optical spectroscopy by considering the absorption of bacteriorhodopsin and scattering. We have applied semiclassical quantum mechanical techniques for the calculation of absorption spectra by taking into account the Fano effects on the ground state of bacteriorhodopsin. A model of the formation of PM-polyacrylamide films has been proposed based on the growth of polymeric chains around purple membrane. Experimentally, the temporal evolution of the polymerization process of acrylamide has been studied as function of the pH solution, obtaining a good correspondence to the proposed model. Thus, due to the formation of intermediate bacteriorhodopsin-doped nanogel, by controlling the polymerization process, an alternative methodology for the synthesis of bacteriorhodopsin-doped nanogels can be provided.

  14. Synchrobetatron resonances

    International Nuclear Information System (INIS)

    1977-03-01

    At the 1975 Particle Accelerator Conference it was reported that a class of resonances were observed in SPEAR II that had not appeared before in SPEAR I. While the existence of sideband resonances of the main betatron oscillation frequencies has been previously observed and analyzed, the resonances observed in SPEAR do not appear to be of the same variety. Experiments were performed at SPEAR to identify the mechanism believed to be the most likely explanation. Some of the current experimental knowledge and theoretical views on the source of these resonances are presented

  15. Snake resonances

    International Nuclear Information System (INIS)

    Tepikian, S.

    1988-01-01

    Siberian Snakes provide a practical means of obtaining polarized proton beams in large accelerators. The effect of snakes can be understood by studying the dynamics of spin precession in an accelerator with snakes and a single spin resonance. This leads to a new class of energy independent spin depolarizing resonances, called snake resonances. In designing a large accelerator with snakes to preserve the spin polarization, there is an added constraint on the choice of the vertical betatron tune due to the snake resonances. 11 refs., 4 figs

  16. Advances in nonlinear optics

    CERN Document Server

    Chen, Xianfeng; Zeng, Heping; Guo, Qi; She, Weilong

    2015-01-01

    This book presents an overview of the state of the art of nonlinear optics from weak light nonlinear optics, ultrafast nonlinear optics to electro-optical theory and applications. Topics range from the fundamental studies of the interaction between matter and radiation to the development of devices, components, and systems of tremendous commercial interest for widespread applications in optical telecommunications, medicine, and biotechnology.

  17. On-line control of the nonlinear dynamics for synchrotrons

    Science.gov (United States)

    Bengtsson, J.; Martin, I. P. S.; Rowland, J. H.; Bartolini, R.

    2015-07-01

    We propose a simple approach to the on-line control of the nonlinear dynamics in storage rings, based on compensation of the nonlinear resonance driving terms using beam losses as the main indicator of the strength of a resonance. The correction scheme is built on the analysis of the resonance driving terms in first perturbative order and on the possibility of using independent power supplies in the sextupole magnets, which is nowadays present in many synchrotron light sources. Such freedom allows the definition of "smart sextupole knobs" attacking each resonance separately. The compensation scheme has been tested at the Diamond light source and proved to be effective in opening up the betatron tune space, resonance free, available to the electron beam and to improve the beam lifetime.

  18. On-line control of the nonlinear dynamics for synchrotrons

    Directory of Open Access Journals (Sweden)

    J. Bengtsson

    2015-07-01

    Full Text Available We propose a simple approach to the on-line control of the nonlinear dynamics in storage rings, based on compensation of the nonlinear resonance driving terms using beam losses as the main indicator of the strength of a resonance. The correction scheme is built on the analysis of the resonance driving terms in first perturbative order and on the possibility of using independent power supplies in the sextupole magnets, which is nowadays present in many synchrotron light sources. Such freedom allows the definition of “smart sextupole knobs” attacking each resonance separately. The compensation scheme has been tested at the Diamond light source and proved to be effective in opening up the betatron tune space, resonance free, available to the electron beam and to improve the beam lifetime.

  19. Modelling of a bridge-shaped nonlinear piezoelectric energy harvester

    International Nuclear Information System (INIS)

    Gafforelli, G; Corigliano, A; Xu, R; Kim, S G

    2013-01-01

    Piezoelectric MicroElectroMechanical Systems (MEMS) energy harvesting is an attractive technology for harvesting small magnitudes of energy from ambient vibrations. Increasing the operating frequency bandwidth of such devices is one of the major issues for real world applications. A MEMS-scale doubly clamped nonlinear beam resonator is designed and developed to demonstrate very wide bandwidth and high power density. In this paper a first complete theoretical discussion of nonlinear resonating piezoelectric energy harvesting is provided. The sectional behaviour of the beam is studied through the Classical Lamination Theory (CLT) specifically modified to introduce the piezoelectric coupling and nonlinear Green-Lagrange strain tensor. A lumped parameter model is built through Rayleigh-Ritz Method and the resulting nonlinear coupled equations are solved in the frequency domain through the Harmonic Balance Method (HBM). Finally, the influence of external load resistance on the dynamic behaviour is studied. The theoretical model shows that nonlinear resonant harvesters have much wider power bandwidth than that of linear resonators but their maximum power is still bounded by the mechanical damping as is the case for linear resonating harvesters

  20. Nonlinear FMR spectra in yttrium iron garnet

    Directory of Open Access Journals (Sweden)

    Yu.M. Bunkov, P.M. Vetoshko, I.G. Motygullin, T.R. Safin, M.S. Tagirov, N.A. Tukmakova

    2015-12-01

    Full Text Available Results of demagnetizing effect studies in yttrium iron garnet Y3Fe5O12 thin films are reported. Experiments were performed on X-Band of electron paramagnetic resonance spectrometer at room temperature. The ferromagnetic resonance (FMR spectra were obtained for one-layer single crystal YIG films for different values of the applied microwave power. Nonlinear FMR spectra transformation by the microwave power increasing in various directions of magnetic field sweep was observed. It is explained by the influence of the demagnetization action of nonequilibrium magnons.