Parametric strong mode-coupling in carbon nanotube mechanical resonators
Li, Shu-Xiao; Zhu, Dong; Wang, Xin-He; Wang, Jiang-Tao; Deng, Guang-Wei; Li, Hai-Ou; Cao, Gang; Xiao, Ming; Guo, Guang-Can; Jiang, Kai-Li; Dai, Xing-Can; Guo, Guo-Ping
2016-08-01
Carbon nanotubes (CNTs) have attracted much attention for use in nanomechanical devices because of their exceptional properties, such as large resonant frequencies, low mass, and high quality factors. Here, we report the first experimental realization of parametric strong coupling between two mechanical modes on a single CNT nanomechanical resonator, by applying an extra microwave pump. This parametric pump method can be used to couple mechanical modes with arbitrary frequency differences. The properties of the mechanical resonator are detected by single-electron tunneling at low temperature, which is found to be strongly coupled to both modes. The coupling strength between the two modes can be tuned by the pump power, setting the coupling regime from weak to strong. This tunability may be useful in further phonon manipulations in carbon nanotubes.Carbon nanotubes (CNTs) have attracted much attention for use in nanomechanical devices because of their exceptional properties, such as large resonant frequencies, low mass, and high quality factors. Here, we report the first experimental realization of parametric strong coupling between two mechanical modes on a single CNT nanomechanical resonator, by applying an extra microwave pump. This parametric pump method can be used to couple mechanical modes with arbitrary frequency differences. The properties of the mechanical resonator are detected by single-electron tunneling at low temperature, which is found to be strongly coupled to both modes. The coupling strength between the two modes can be tuned by the pump power, setting the coupling regime from weak to strong. This tunability may be useful in further phonon manipulations in carbon nanotubes. Electronic supplementary information (ESI) available: Fit of the quality factor and similar results in more devices. See DOI: 10.1039/c6nr02853e
Synchrobetatron resonant coupling mechanism in a storage ring
Kouichi Jimbo
2016-01-01
Full Text Available A clear synchrobetatron resonant coupling of Mg ion beam was observed experimentally in the horizontal laser beam cooling experiment in small laser equipped storage ring. Synchrotron and horizontal betatron motions were intentionally coupled in a rf cavity. Using the Hamiltonian which is composed of coasting, synchrotron and betatron motions, physical mechanism of the coupling is analyzed to explain the observed horizontal betatron tune jump near the synchrobetatron resonant coupling point. There energy exchange between the synchrotron oscillation and the horizontal betatron oscillation was mediated by coasting particles and the freedom of the horizontal direction is connected with the freedom of the longitudinal direction.
Resonance of electromagnetic and mechanic coupling in hydro-generator
YAO Da-kun; ZOU Jing-xiang; QU Da-zhuang; ZHAO Shu-shan; YU Kai-ping
2006-01-01
Electromagnetic and mechanical forces are main reasons of oscillations in hydro-generators. The oscillation is fairly complicated as to the coupling of them. Using the method of multiple scales in nonlinear oscillations, instabilities of hydro-generator rotors caused by the unbalanced magnetic pull, which comes from the eccentricity of the rotor, are discussed. Considering nonlinear properties of the unbalanced magnetic pull, the super-harmonic resonance phenomena are observed as the critical rotating speed of rotors is close to twice of the operating speed. This is verified by a model experiment, and should be considered during the design of hydrogenerator rotors.
Friedmann, Thomas Aquinas; Czaplewski, David A.; Sullivan, John Patrick; Modine, Normand Arthur; Wendt, Joel Robert; Aslam, Dean (Michigan State University, Lansing, MI); Sepulveda-Alancastro, Nelson (University of Puerto Rico, Mayaguez, PR)
2007-01-01
Understanding internal dissipation in resonant mechanical systems at the micro- and nanoscale is of great technological and fundamental interest. Resonant mechanical systems are central to many sensor technologies, and microscale resonators form the basis of a variety of scanning probe microscopies. Furthermore, coupled resonant mechanical systems are of great utility for the study of complex dynamics in systems ranging from biology to electronics to photonics. In this work, we report the detailed experimental study of internal dissipation in micro- and nanomechanical oscillators fabricated from amorphous and crystalline diamond materials, atomistic modeling of dissipation in amorphous, defect-free, and defect-containing crystalline silicon, and experimental work on the properties of one-dimensional and two-dimensional coupled mechanical oscillator arrays. We have identified that internal dissipation in most micro- and nanoscale oscillators is limited by defect relaxation processes, with large differences in the nature of the defects as the local order of the material ranges from amorphous to crystalline. Atomistic simulations also showed a dominant role of defect relaxation processes in controlling internal dissipation. Our studies of one-dimensional and two-dimensional coupled oscillator arrays revealed that it is possible to create mechanical systems that should be ideal for the study of non-linear dynamics and localization.
Optically induced strong intermodal coupling in mechanical resonators at room temperature
Ohta, R.; Okamoto, H.; Yamaguchi, H. [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198 (Japan); Hey, R.; Friedland, K. J. [Paul-Drude-Institut fur Festkörperelektronik, Hausvogteiplatz 5–7, 10117 Berlin (Germany)
2015-08-31
Strong parametric mode coupling in mechanical resonators is demonstrated at room temperature by using the photothermal effect in thin membrane structures. Thanks to the large stress modulation by laser irradiation, the coupling rate of the mechanical modes, defined as half of the mode splitting, reaches 2.94 kHz, which is an order of magnitude larger than electrically induced mode coupling. This large coupling rate exceeds the damping rates of the mechanical resonators and results in the strong coupling regime, which is a signature of coherent mode interaction. Room-temperature coherent mode coupling will enable us to manipulate mechanical motion at practical operation temperatures and provides a wide variety of applications of integrated mechanical systems.
Plasmon-Induced Resonant Energy Transfer: a coherent dipole-dipole coupling mechanism
Bristow, Alan D.; Cushing, Scott K.; Li, Jiangtian; Wu, Nianqiang
Metal-insulator-semiconductor core-shell nanoparticles have been used to demonstrate a dipole-dipole coupling mechanism that is entirely dependent on the dephasing time of the localized plasmonic resonance. Consequently, the short-time scale of the plasmons leads to broad energy uncertainty that allows for excitation of charge carriers in the semiconductor via stimulation of photons with energies below the energy band gap. In addition, this coherent energy transfer process overcomes interfacial losses often associated with direct charge transfer. This work explores the efficiency of the energy transfer process, the dipole-dipole coupling strength with dipole separation, shell thickness and plasmonic resonance overlap. We demonstrate limits where the coherent nature of the coupling is switched off and charge transfer processes can dominate. Experiments are performed using transient absorption spectroscopy. Results are compared to calculations using a quantum master equation. These nanostructures show strong potential for improving solar light-harvesting for power and fuel generation.
Martinez, Luis A.; Castelli, Alessandro R.; Delmas, William; Sharping, Jay E.; Chiao, Raymond
2016-11-01
We present experimental and theoretical results for the excitation of a mechanical oscillator via radiation pressure with a room-temperature system employing a relatively low-(Q) centimeter-size mechanical oscillator coupled to a relatively low-Q standard three-dimensional radio-frequency (RF) cavity resonator. We describe the forces giving rise to optomechanical coupling using the Maxwell stress tensor and show that nanometer-scale displacements are possible and experimentally observable. The experimental system is composed of a 35 mm diameter silicon nitride membrane sputtered with a 300 nm gold conducting film and attached to the end of a RF copper cylindrical cavity. The RF cavity is operated in its {{TE}}011 mode and amplitude modulated on resonance with the fundamental drum modes of the membrane. Membrane motion is monitored using an unbalanced, non-zero optical path difference, optically filtered Michelson interferometer capable of measuring sub-nanometer displacements.
Ultra-cold mechanical resonators coupled to atoms in an optical lattice
Geraci, Andrew A
2009-01-01
We propose an experiment utilizing an array of cooled micro-cantilevers coupled to a sample of ultra-cold atoms trapped near a micro-fabricated surface. The cantilevers allow individual lattice site addressing for atomic state control and readout, and potentially may be useful in optical lattice quantum computation schemes. Assuming resonators can be cooled to their vibrational ground state, the implementation of a two-qubit controlled-NOT gate with atomic internal states and the motional states of the resonator is described. We also consider a protocol for entangling two or more cantilevers on the atom chip with different resonance frequencies, using the trapped atoms as an intermediary. Although similar experiments could be carried out with magnetic microchip traps, the optical confinement scheme we consider may exhibit reduced near-field magnetic noise and decoherence. Prospects for using this novel system for tests of quantum mechanics at macroscopic scales or quantum information processing are discussed.
Song, Song-Kum
2016-01-01
Mechanism of the Fano resonances in planar metamaterials demonstrate based on the coupled two-oscillator model. We have described the optical spectrums like reflectance and transmittance near the resonances of bright mode (continuum mode) and dark mode (discrete mode) and explained their optical properties by the Fano formulism. the Fano formulism of the resonances in the planar metamaterials can predict the asymmetric shape line and radiative properties occurring in reflectance and transmittance from the coupling between bright and dark modes.
Enhanced interaction between a mechanical oscillator and two coupled resonant electrical circuits
Dmitriev, A V
2014-01-01
This paper reports result of calculation and experimental realization of an electromechanical system that consists of a high-Q mechanical oscillator parametrically coupled in the manner of a capacitive transducer with a RF circuit, which is in turn inductively coupled with another RF circuit. The system operates in the resolved sideband regime when the mechanical oscillator's frequency is larger than the electrical circuits' bandwidths. Using two coupled RF circuits allowed one to enhance the interaction between them and the mechanical oscillator which is one of flexural vibrational modes of a free-edge circular silicon wafer. Such a coupled electromechanical system can be used as a high-sensitive capacitive vibration sensor.
Ulmer, W; Halberg, F; Schwarzkopff, O
2011-01-01
The existence of specific biorhythms and the role of geomagnetic and/or solar magnetic activities are well-established by appropriate correlations in chronobiology. From a physical viewpoint, there are two different accesses to biorhythms to set up connections to molecular processes: 1. Diffusion of charged molecules in magnetic fields. 2. Quantum mechanical perturbation theoretical methods and their resonance dominators to characterize specific interactions between constituents. The methods of point 2 permit the treatment of molecular processes by circuits with characteristic resonances and 'beat-frequencies', which result from the primarily fast physical processes. As examples the tunneling processes between DNA base pairs (H bonds) and the ATP decomposition are considered.
Coupled resonator vertical cavity laser
Choquette, K.D.; Chow, W.W.; Hou, H.Q.; Geib, K.M.; Hammons, B.E.
1998-01-01
The monolithic integration of coupled resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the interaction between the cavities. The authors report the first electrically injected coupled resonator vertical-cavity laser diode and demonstrate novel characteristics arising from the cavity coupling, including methods for external modulation of the laser. A coupled mode theory is used model the output modulation of the coupled resonator vertical cavity laser.
Viscoelastic coupling of nanoelectromechanical resonators.
Simonson, Robert Joseph; Staton, Alan W.
2009-09-01
This report summarizes work to date on a new collaboration between Sandia National Laboratories and the California Institute of Technology (Caltech) to utilize nanoelectromechanical resonators designed at Caltech as platforms to measure the mechanical properties of polymeric materials at length scales on the order of 10-50 nm. Caltech has succeeded in reproducibly building cantilever resonators having major dimensions on the order of 2-5 microns. These devices are fabricated in pairs, with free ends separated by reproducible gaps having dimensions on the order of 10-50 nm. By controlled placement of materials that bridge the very small gap between resonators, the mechanical devices become coupled through the test material, and the transmission of energy between the devices can be monitored. This should allow for measurements of viscoelastic properties of polymeric materials at high frequency over short distances. Our work to date has been directed toward establishing this measurement capability at Sandia.
Zielinski, M.L.; van Lenthe, J.H.
2008-01-01
The resonating block localize wave function (RBLW) method is introduced, a resonating modification of the block localized wave functions introduced by Mo et al. [Mo, Y.; Peyerimhoff, S. D. J. Chem. Phys. 1998, 109, 1687].This approach allows the evaluation of resonance energies following Pauling’s r
Zhou, Mingqiong; Peng, Jingdong; He, Rongxing; He, Yuting; Zhang, Jing; Li, Aiping
2015-02-01
A reliable and versatile high performance liquid chromatography coupled with resonance Rayleigh scattering method was established for the determination of three fluoroquinolones, including levofloxacin, norfloxacin and enrofloxacin in water sample and human urine sample. In pH 4.4-4.6 Britton-Robinson buffer medium, the fluoroquinolones separated by high performance liquid chromatography could react with erythrosine to form 1:1 ion-association complexes, which could make contributions to the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex = λem = 330 nm. The resonance Rayleigh scattering spectral characteristics of the drugs and the experimental conditions such as pH, detection wavelength, erythrosine concentration, flow rate, the length of reaction tube were studied. Quantum chemistry calculation, Fourier transform infrared spectroscopy and absorption spectroscopy were used to discuss the reaction mechanism. The recoveries of samples added standard ranged from 97.53% to 102.00%, and the relative standard deviation was below 4.64%. The limit of detection (S/N = 3) of 0.05-0.12 μg mL-1 was reached, and the linear regression coefficients were all above 0.999. The proposed method was proved as a simple, low cost and high sensitivity method.
Coupled-resonator optical waveguides
Raza, Søren; Grgic, Jure; Pedersen, Jesper Goor
2010-01-01
Coupled-resonator optical waveguides hold potential for slow-light propagation of optical pulses. The dispersion properties may adequately be analyzed within the framework of coupled-mode theory. We extend the standard coupled-mode theory for such structures to also include complex-valued paramet...
Dispersive coupling between light and a rare-earth-ion-doped mechanical resonator
Mølmer, Klaus; Le Coq, Yann; Seidelin, Signe
2016-11-01
By spectrally hole burning an inhomogeneously broadened ensemble of ions while applying a controlled perturbation, one can obtain spectral holes that are functionalized for maximum sensitivity to different perturbations. We propose to use such hole-burned structures for the dispersive optical interaction with rare-earth-ion dopants whose frequencies are sensitive to crystal strain due to the bending motion of a crystal cantilever. A quantitative analysis shows that good optical sensitivity to the bending motion is obtained if a magnetic-field gradient is applied across the crystal during hole burning and that the resulting optomechanical coupling strength is sufficient for observing quantum features such as zero-point vibrations.
Induced transparency in optomechanically coupled resonators
Duan, Zhenglu; Stace, Thomas M; Milburn, G J; Holmes, Catherine A
2015-01-01
In this work we theoretically investigate a hybrid system of two optomechanically coupled resonators, which exhibits induced transparency. This is realized by coupling an optical ring resonator to a toroid. In the semiclassical analyses, the system displays bistabilities, isolated branches (isolas) and self-sustained oscillation dynamics. Furthermore, we find that the induced transparency transparency window sensitively relies on the mechanical motion. Based on this fact, we show that the described system can be used as a weak force detector and the optimal sensitivity can beat the standard quantum limit without using feedback control or squeezing under available experimental conditions.
Murao, Tadashi; Saitoh, Kunimasa; Koshiba, Masanori
2011-01-31
In this paper, we propose a novel mechanism for suppression of higher-order modes (HOMs), namely multiple resonant coupling, in all-solid photonic bandgap fibers (PBGFs) with effectively large core diameters. In an analogy to the well-known tight-binding theory in solid-state physics, multiple anti-resonant reflecting optical waveguide (ARROW) modes bound in designedly arranged defects in the cladding make up Bloch states and resultant photonic bands with a finite effective-index width, which contribute to the suppression of HOMs. In particular, contrary to the conventional method for the HOM suppression using the index-matching of the HOMs in the core of the PBGF and the defect mode arranged in the cladding, the proposed mechanism guarantees a broadband HOM suppression without a precise structural design. This effect is explained by the multiple resonant coupling, as well as an enhanced confinement loss mechanism which occurs near the condition satisfying the multiple resonant coupling. Moreover, we show that the proposed structure exhibits a lower bending loss characteristic when compared to the conventional all-solid PBGFs. The simultaneous realization of the single-mode operation and the low bending loss property is due to the novel cladding concept named as heterostructured cladding. The proposed structure also resolves the issue for the increased confinement loss property in the first-order photonic bandgap (PBG) at the same time.
A sound absorbing metasurface with coupled resonators
Li, Junfei; Wang, Wenqi; Xie, Yangbo; Popa, Bogdan-Ioan; Cummer, Steven A.
2016-08-01
An impedance matched surface is able, in principle, to totally absorb the incident sound and yield no reflection, and this is desired in many acoustic applications. Here we demonstrate a design of impedance matched sound absorbing surface with a simple construction. By coupling different resonators and generating a hybrid resonance mode, we designed and fabricated a metasurface that is impedance-matched to airborne sound at tunable frequencies with subwavelength scale unit cells. With careful design of the coupled resonators, over 99% energy absorption at central frequency of 511 Hz with a 50% absorption bandwidth of 140 Hz is achieved experimentally. The proposed design can be easily fabricated, and is mechanically stable. The proposed metasurface can be used in many sound absorption applications such as loudspeaker design and architectural acoustics.
Wallace, John; Newman, Mike; Gutierrez, Homero; Hoffman, Charlie; Quakenbush, Tim; Waldeck, Dan; Leone, Christopher; Ostaszewski, Miro
2014-10-01
Ball Aerospace & Technologies Corp. developed a Resonant Scanning Mechanism (RSM) capable of combining a 250- Hz resonant scan about one axis with a two-hertz triangular scan about the orthogonal axis. The RSM enables a rapid, high-density scan over a significant field of regard (FOR) while minimizing size, weight, and power requirements. The azimuth scan axis is bearing mounted allowing for 30° of mechanical travel, while the resonant elevation axis is flexure and spring mounted with five degrees of mechanical travel. Pointing-knowledge error during quiescent static pointing at room temperature across the full range is better than 100 μrad RMS per axis. The compact design of the RSM, roughly the size of a soda can, makes it an ideal mechanism for use on low-altitude aircraft and unmanned aerial vehicles. Unique aspects of the opto-mechanical design include i) resonant springs which allow for a high-frequency scan axis with low power consumption; and ii) an independent lower-frequency scan axis allowing for a wide FOR. The pointing control system operates each axis independently and employs i) a position loop for the azimuth axis; and ii) a unique combination of parallel frequency and amplitude control loops for the elevation axis. All control and pointing algorithms are hosted on a 200-MHz microcontroller with 516 KB of RAM on a compact 3"×4" digital controller, also of Ball design.
Reconfigurable optical routers based on Coupled Resonator Induced Transparency resonances.
Mancinelli, M; Bettotti, P; Fedeli, J M; Pavesi, L
2012-10-08
The interferometric coupling of pairs of resonators in a resonator sequence generates coupled ring induced transparency (CRIT) resonances. These have quality factors an order of magnitude greater than those of single resonators. We show that it is possible to engineer CRIT resonances in tapered SCISSOR (Side Coupled Integrated Space Sequence of Resonator) to realize fast and efficient reconfigurable optical switches and routers handling several channels while keeping single channel addressing capabilities. Tapered SCISSORs are fabricated in silicon-on-insulator technology. Furthermore, tapered SCISSORs show multiple-channel switching behavior that can be exploited in DWDM applications.
Nanoantenna using mechanical resonance
Chang Hwa Lee,
2010-11-01
Nanoantenna using mechanical resonance vibration is made from an indium tin oxide (ITO) coated vertically aligned nanorod array. Only this structure works as a radio with demodulator without any electrical circuit using field emission phenomenon. A top-down fabrication method of an ITO coated nanorod array is proposed using a modified UV lithography. The received radio frequency and the resonance frequency of nanoantenna can be controlled by the fabrication condition through the height of a nanorod array. The modulated signals are received successfully with the transmission carrier wave frequency (248MHz) and the proposed nanoantenna is expected to be used in communication system for ultra small scale sensor. ©2010 IEEE.
Savariraj, Dennyson A.; Kim, Hee-Je; Viswanathan, Kodakkal K.; Vijayakumar, M.; Prabakar, Kandasamy
2016-02-15
Cu2-xS thin films prepared by template free single step wet chemical method on fluorine doped tin oxide substrate without any surfactant exhibts localized surface plasmon resonance (LSPR) coupled exciton effects. Cu2-xS thin films of unique surface morphology and free carrier density due to copper vacancy is controlled by the growth temperature and time. These selectively grown Cu2-xS thin films possess tunable band gap (2.6 - 1.4 eV) due to quantum size effect. Eventhough, all the samples show satellite peak in the X-ray photoelectron spectra due to Cu vacancies, only the samples with higher oxygen concentration show LSPR in the near infrared region.
Loop coupled resonator optical waveguides.
Song, Junfeng; Luo, Lian-Wee; Luo, Xianshu; Zhou, Haifeng; Tu, Xiaoguang; Jia, Lianxi; Fang, Qing; Lo, Guo-Qiang
2014-10-06
We propose a novel coupled resonator optical waveguide (CROW) structure that is made up of a waveguide loop. We theoretically investigate the forbidden band and conduction band conditions in an infinite periodic lattice. We also discuss the reflection- and transmission- spectra, group delay in finite periodic structures. Light has a larger group delay at the band edge in a periodic structure. The flat band pass filter and flat-top group delay can be realized in a non-periodic structure. Scattering matrix method is used to calculate the effects of waveguide loss on the optical characteristics of these structures. We also introduce a tunable coupling loop waveguide to compensate for the fabrication variations since the coupling coefficient of the directional coupler in the loop waveguide is a critical factor in determining the characteristics of a loop CROW. The loop CROW structure is suitable for a wide range of applications such as band pass filters, high Q microcavity, and optical buffers and so on.
Sign-Reversal Coupling in Coupled-Resonator Optical Waveguide
Gao, Zhen; Zhang, Youming; Zhang, Baile
2016-01-01
Coupled-resonator optical waveguides (CROWs), which play a significant role in modern photonics, achieve waveguiding through near-field coupling between tightly localized resonators. The coupling factor, a critical parameter in CROW theory, determines the coupling strength between two resonators and the waveguiding dispersion of a CROW. However, the original CROW theory proposed by Yariv et al. only demonstrated one value of coupling factor for a multipole resonance mode. Here, by imaging the tight-binding Bloch waves on a CROW consisting of designer-surface-plasmon resonators in the microwave regime, we demonstrate that the coupling factor in the CROW theory can reverse its sign for a multipole resonance mode. This determines two different waveguiding dispersion curves in the same frequency range, experimentally confirmed by matching Bloch wavevectors and frequencies in the CROW. Our study supplements and extends the original CROW theory, and may find novel use in functional photonic systems.
Characterizing coupled MEMS resonators with an electrical resonator
Tao, Guowei; Choubey, Bhaskar
2016-10-01
Rapid development in micro/nano fabrication has enabled the shrinking of MEMS devices and the ability to fabricate them in large arrays. However, process variations and device mismatch have also raised testability issues in the MEMS industry. MEMS resonators have been coupled to simplify the characterization of the fabrication process and device performance using their collective behaviour. Perturbation analysis using eigenvalues can therefore be applied to extract the system matrix of coupled resonators. We propose a new way of perturbation analysis by coupling an electrical resonator to an array of MEMS resonators. The electrical resonator is simple in structure and easy to readout. It can also precisely control the amount of perturbation based on two available techniques. Coupling between MEMS resonators and electrical resonator opens a new window for process characterization, device testing, material characterization, as well as large sensors array actuation.
Energy harvesting with coupled magnetostrictive resonators
Naik, Suketu; Phipps, Alex; In, Visarath; Cavaroc, Peyton; Matus-Vargas, Antonio; Palacios, Antonio; Gonzalez-Hernandez, H. G.
2014-03-01
We report the investigation of an energy harvesting system composed of coupled resonators with the magnetostrictive material Galfenol (FeGa). A coupled system of meso-scale (1-10 cm) cantilever beams for harvesting vibration energy is described for powering and aiding the performance of low-power wireless sensor nodes. Galfenol is chosen in this work for its durability, compared to the brittleness often encountered with piezoelectric materials, and high magnetomechanical coupling. A lumped model, which captures both the mechanical and electrical behavior of the individual transducers, is first developed. The values of the lumped element parameters are then derived empirically from fabricated beams in order to compare the model to experimental measurements. The governing equations of the coupled system lead to a system of differential equations with all-to-all coupling between transducers. An analysis of the system equations reveals different patterns of collective oscillations. Among the many different patterns, a synchronous state appears to yield the maximum energy that can be harvested by the system. Experiments on coupled system shows that the coupled system exhibits synchronization and an increment in the output power. Discussion of the required power converters is also included.
Piezoelectric Voltage Coupled Reentrant Cavity Resonator
Carvalho, Natalia C; Floch, Jean-Michel Le; Tobar, Michael Edmund
2014-01-01
A piezoelectric voltage coupled microwave reentrant cavity has been developed. The central cavity post is bonded to a piezoelectric actuator allowing the voltage control of small post displacements over a high dynamic range. We show that such a cavity can be implemented as a voltage tunable resonator, a transducer for exciting and measuring mechanical modes of the structure and a transducer for measuring comparative sensitivity of the piezoelectric material. Experiments were conducted at room and cryogenic temperatures with results verified using Finite Element software.
Coupling Bright and Dark Plasmonic Lattice Resonances
Rodriguez, S R K; Maes, B; Janssen, O T A; Vecchi, G; Rivas, J Gomez
2011-01-01
We demonstrate the coupling of bright and dark Surface Lattice Resonances (SLRs), which are collective Fano resonances in 2D plasmonic crystals. As a result of this coupling, a frequency stop-gap in the dispersion relation of SLRs is observed. The different field symmetries of the low and high frequency SLR bands lead to pronounced differences in their coupling to free space radiation. Standing waves of very narrow spectral width compared to localized surface plasmon resonances are formed at the high frequency band edge, while subradiant damping onsets at the low frequency band edge leading the resonance into darkness. We introduce a coupled oscillator analog to the plasmonic crystal, which serves to elucidate the physics of the coupled plasmonic resonances and to estimate very high quality factors (Q>700) for SLRs, which are the highest known for any 2D plasmonic crystal.
Coupled Optical Resonance Laser Lockin
Burd, Shaun
2013-01-01
We have demonstrated simultaneous laser frequency stabilization of a UV and IR laser, to the same spectroscopic sample, by monitoring only the absorption of the UV laser. For trapping and cooling Yb$^{+}$ ions, a frequency stabilized laser is required at 369.95nm to drive the $^{2}S_{1/2}$ $ \\rightarrow $ $ ^{2}P_{1/2}$ cooling transition. Since the cycle is not closed, a 935.18nm laser is needed to drive the $^{2}D_{3/2}$ $\\rightarrow$ $^{3}D_{[3/2]1/2}$ transition which is followed by rapid decay to the $^{2}S_{1/2}$ state. Our 369nm laser is locked to Yb$^{+}$ ions generated in a hollow cathode discharge lamp using saturated absorption spectroscopy. Without pumping, the metastable $^{2}D_{3/2}$ level is only sparsely populated and direct absorption of 935nm light is difficult to detect. A resonant 369nm laser is able to significantly populate the $^{2}D_{3/2}$ state due to the coupling between the levels. Fast re-pumping to the $^{2}S_{1/2}$ state, by 935nm light, can be detected by observing the change in...
Strong and tunable mode coupling in carbon nanotube resonators
Castellanos Gomez, A.; Meerwaldt, H.B.; Ventra, W.J.; Van der Zant, H.S.J.; Steele, G.A.
2012-01-01
The nonlinear interaction between two mechanical resonances of the same freely suspended carbon nanotube resonator is studied. We find that, in the Coulomb-blockade regime, the nonlinear modal interaction is dominated by single-electron-tunneling processes and that the mode-coupling parameter can be
Gräfenstein, Jürgen; Cremer, Dieter
2004-12-22
For the first time, the nuclear magnetic resonance (NMR) spin-spin coupling mechanism is decomposed into one-electron and electron-electron interaction contributions to demonstrate that spin-information transport between different orbitals is not exclusively an electron-exchange phenomenon. This is done using coupled perturbed density-functional theory in conjunction with the recently developed J-OC-PSP [=J-OC-OC-PSP: Decomposition of J into orbital contributions using orbital currents and partial spin polarization)] method. One-orbital contributions comprise Ramsey response and self-exchange effects and the two-orbital contributions describe first-order delocalization and steric exchange. The two-orbital effects can be characterized as external orbital, echo, and spin transport contributions. A relationship of these electronic effects to zeroth-order orbital theory is demonstrated and their sign and magnitude predicted using simple models and graphical representations of first order orbitals. In the case of methane the two NMR spin-spin coupling constants result from totally different Fermi contact coupling mechanisms. (1)J(C,H) is the result of the Ramsey response and the self-exchange of the bond orbital diminished by external first-order delocalization external one-orbital effects whereas (2)J(H,H) spin-spin coupling is almost exclusively mitigated by a two-orbital steric exchange effect. From this analysis, a series of prediction can be made how geometrical deformations, electron lone pairs, and substituent effects lead to a change in the values of (1)J(C,H) and (2)J(H,H), respectively, for hydrocarbons.
Critical coupling in plasmonic resonator arrays
Balci, Sinan; Kocabas, Coskun; Aydinli, Atilla
2011-08-01
We report critical coupling of electromagnetic waves to plasmonic cavity arrays fabricated on Moiré surfaces. Dark field plasmon microscopy imaging and polarization dependent spectroscopic reflection measurements reveal the critical coupling conditions of the cavities. The critical coupling conditions depend on the superperiod of the Moiré surface, which also defines the coupling between the cavities. Complete transfer of the incident power can be achieved for traveling wave plasmonic resonators, which have a relatively short superperiod. When the superperiod of the resonators increases, the coupled resonators become isolated standing wave resonators in which complete transfer of the incident power is not possible. Analytical and finite difference time domain calculations support the experimental observations.
Photonic molecules formed by coupled hybrid resonators
Peng, Bo; Zhu, Jiangang; Yang, Lan; 10.1364/OL.37.003435
2013-01-01
We describe a method that enables free-standing whispering-gallery-mode microresonators, and report spectral tuning of photonic molecules formed by coupled free and on-chip resonators with different geometries and materials. We study direct coupling via evanescent fields of free silica microtoroids and microspheres with on-chip polymer coated silica microtoroids. We demonstrate thermal tuning of resonance modes to achieve maximal spectral overlap, mode splitting induced by direct coupling, and the effects of distance between the resonators on the splitting spectra.
Strong and tunable mode coupling in carbon nanotube resonators
Castellanos-Gomez, Andres; Meerwaldt, Harold B.; Venstra, Warner J.; van der Zant, Herre S. J.; Steele, Gary A.
2012-07-01
The nonlinear interaction between two mechanical resonances of the same freely suspended carbon nanotube resonator is studied. We find that, in the Coulomb-blockade regime, the nonlinear modal interaction is dominated by single-electron-tunneling processes and that the mode-coupling parameter can be tuned with the gate voltage, allowing both mode-softening and mode-stiffening behaviors. This is in striking contrast to tension-induced mode coupling in strings where the coupling parameter is positive and gives rise to a stiffening of the mode. The strength of the mode coupling in carbon nanotubes in the Coulomb-blockade regime is observed to be 6 orders of magnitude larger than the mechanical-mode coupling in micromechanical resonators.
Superconducting Resonant Inductive Power Coupling Project
National Aeronautics and Space Administration — The proposed effort will develop a technology to wirelessly and efficiently transfer power over hundreds of meters via resonant inductive coupling. The key...
Study of Mode Coupling on Coaxial Resonators
Rui Liu; Hong-Fu Li
2011-01-01
A study of mode coupling phenomenon of coaxial resonators has been conducted with theories.Through establishing the source-free transmission line equation,boundary conditions of the coaxial resonators with a corrugated inner conductor are analyzed.In the end,calculations are performed in a wide range of corrugation parameters for the resonator of the Karisruhe Institute of Technology (KIT) relevant coaxial gyrotron.
Photoelastic coupling in gallium arsenide optomechanical disk resonators
Baker, Christopher; Nguyen, Dac-Trung; Andronico, Alessio; Ducci, Sara; Leo, Giuseppe; Favero, Ivan
2014-01-01
We analyze the magnitude of the radiation pressure and electrostrictive stresses exerted by light confined inside GaAs semiconductor WGM optomechanical disk resonators, through analytical and numerical means, and find the electrostrictive force to be of prime importance. We investigate the geometric and photoelastic optomechanical coupling resulting respectively from the deformation of the disk boundary and from the strain-induced refractive index changes in the material, for various mechanical modes of the disks. Photoelastic optomechanical coupling is shown to be a predominant coupling mechanism for certain disk dimensions and mechanical modes, leading to total coupling g$_{om}$ and g$_0$ reaching respectively 3 THz/nm and 4 MHz. Finally, we point towards ways to maximize the photoelastic coupling in GaAs disk resonators, and we provide some upper bounds for its value in various geometries.
Phonon blockade in a nanomechanical resonator resonantly coupled to a qubit
Xu, Xun-Wei; Liu, Yu-xi
2016-01-01
We study phonon statistics in a nanomechanical resonator (NAMR) which is resonantly coupled to a qubit. We find that there are two different mechanisms for phonon blockade in such a resonantly coupled NAMR-qubit system. One is due to the strong anharmonicity of the NAMR-qubit system with large coupling strength; the other one is due to the destructive interference between different paths for two-phonon excitation in the NAMR-qubit system with a moderate coupling strength. In order to enlarge the mean phonon number for strong phonon antibunching with a moderate NAMR-qubit coupling strength, we assume that two external driving fields are applied to the NAMR and qubit, respectively. In this case, we find that the phonon blockades under two mechanisms can appear at the same frequency regime by optimizing the strength ratio and phase difference of the two external driving fields.
Optical wavelength conversion via optomechanical coupling in a silica resonator
Dong, Chunhua; Fiore, Victor; Kuzyk, Mark C.; Wang, Hailin [Department of Physics, University of Oregon, Eugene, OR (United States); Tian, Lin [University of California, Merced, CA (United States)
2015-01-01
In an optomechanical resonator, an optically active mechanical mode can couple to any of the optical resonances via radiation pressure. This unique property can enable a remarkable phenomenon: conversion of optical fields via optomechanical coupling between vastly different wavelengths. Here we expand an earlier experimental study [Science 338, 1609 (2012)] on classical wavelength conversion of coherent optical fields by coupling two optical modes to a mechanical breathing mode in a silica resonator. Heterodyne detection of the converted optical fields shows that the wavelength conversion process is coherent and bidirectional. The conversion efficiency obtained features a distinct saturation behavior that arises from optomechanical impedance matching. A measurement of the coherent mechanical excitation involved in the wavelength conversion process also provides additional insight on the underlying optomechanical interactions. (copyright 2014 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Direct Coupling From WGM Resonator Disks to Photodetectors
Savchenkov, Antoliy; Maleki, Lute; Mohageg, Makan; Le, Thanh
2007-01-01
Output coupling of light from a whispering- gallery-mode (WGM) optical resonator directly to a photodetector has recently been demonstrated. By directly is meant that the coupling is effected without use of intervening optical components. Heretofore, coupling of light into and out of WGM resonators has been a complex affair involving the use of such optical components as diamond or glass prisms, optical fibers, coated collimators, and/or fiber tapers. Alignment of these components is time-consuming and expensive. To effect direct coupling, one simply mounts a photodetector in direct mechanical contact with a spacer that is, in turn, in direct mechanical contact with a WGM resonator disk. The spacer must have a specified thickness (typically of the order of a wavelength) and an index of refraction lower, by an adequate margin, than the indices of refraction of the photodetector and the WGM resonator disk. This mechanically simple approach makes it possible to obtain an optimum compromise between maximizing optical coupling and maximizing the resonance quality factor (Q).
Diffractively coupled Fabry-Perot resonator with power-recycling
Britzger, Michael; Kroker, Stefanie; Brückner, Frank; Burmeister, Oliver; Kley, Ernst-Bernhard; Tünnermann, Andreas; Danzmann, Karsten; Schnabel, Roman
2011-01-01
We demonstrate the optical coupling of two cavities without light transmission through a substrate. Compared to a conventional coupling component, that is a partially transmissive mirror, an all-reflective coupler avoids light absorption in the substrate and therefore associated thermal problems, and even allows the use of opaque materials with possibly favourable mechanical and thermal properties. Recently, the all-reflective coupling of two cavities with a low-efficiency 3-port diffraction grating was theoretically investigated. Such a grating has an additional (a third) port. However, it was shown that the additional port does not necessarily decrease the bandwidth of the coupled cavities. Such an all-reflective scheme for cavity coupling is of interest in the field of gravitational wave detection. In such detectors light that is resonantly enhanced inside the so-called power-recycling cavity is coupled to (kilometre-scale) Fabry-Perot resonators representing the arms of a Michelson interferometer. In orde...
Dynamic nonlinear thermal optical effects in coupled ring resonators
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.
Capture into resonance of coupled Duffing oscillators.
Kovaleva, Agnessa
2015-08-01
In this paper we investigate capture into resonance of a pair of coupled Duffing oscillators, one of which is excited by periodic forcing with a slowly varying frequency. Previous studies have shown that, under certain conditions, a single oscillator can be captured into persistent resonance with a permanently growing amplitude of oscillations (autoresonance). This paper demonstrates that the emergence of autoresonance in the forced oscillator may be insufficient to generate oscillations with increasing amplitude in the attachment. A parametric domain, in which both oscillators can be captured into resonance, is determined. The quasisteady states determining the growth of amplitudes are found. An agreement between the theoretical and numerical results is demonstrated.
Coupled Resonator Vertical Cavity Laser Diode
CHOQUETTE, KENT D.; CHOW, WENG W.; FISCHER, ARTHUR J.; GEIB, KENT M.; HOU, HONG Q.
1999-09-16
We report the operation of an electrically injected monolithic coupled resonator vertical cavity laser which consists of an active cavity containing In{sub x}Ga{sub 1{minus}x}As quantum wells optically coupled to a passive GaAs cavity. This device demonstrates novel modulation characteristics arising from dynamic changes in the coupling between the active and passive cavities. A composite mode theory is used to model the output modulation of the coupled resonator vertical cavity laser. It is shown that the laser intensity can be modulated by either forward or reverse biasing the passive cavity. Under forward biasing, the modulation is due to carrier induced changes in the refractive index, while for reverse bias operation the modulation is caused by field dependent cavity enhanced absorption.
Coupled optical resonance laser locking.
Burd, S C; du Toit, P J W; Uys, H
2014-10-20
We have demonstrated simultaneous laser frequency stabilization of a UV and IR laser, to coupled transitions of ions in the same spectroscopic sample, by detecting only the absorption of the UV laser. Separate signals for locking the different lasers are obtained by modulating each laser at a different frequency and using lock-in detection of a single photodiode signal. Experimentally, we simultaneously lock a 369 nm and a 935 nm laser to the (2)S(1/2) → (2)(P(1/2) and (2)D(3/2) → (3)D([3/2]1/2) transitions, respectively, of Yb(+) ions generated in a hollow cathode discharge lamp. Stabilized lasers at these frequencies are required for cooling and trapping Yb(+) ions, used in quantum information and in high precision metrology experiments. This technique should be readily applicable to other ion and neutral atom systems requiring multiple stabilized lasers.
Nonlinearly Coupled Superconducting Lumped Element Resonators
Collodo, Michele C.; Potočnik, Anton; Rubio Abadal, Antonio; Mondal, Mintu; Oppliger, Markus; Wallraff, Andreas
We study SQUID-mediated tunable coupling between two superconducting on-chip resonators in the microwave frequency range. In this circuit QED implementation, we employ lumped-element type resonators, which consist of Nb thin film structured into interdigitated finger shunt capacitors and meander inductors. A SQUID, functioning as flux dependent and intrinsically nonlinear inductor, is placed as a coupling element together with an interdigitated capacitor between the two resonators (cf. A. Baust et al., Phys Rev. B 91 014515 (2015)). We perform a spectroscopic measurement in a dilution refrigerator and find the linear photon hopping rate between the resonators to be widely tunable as well as suppressible for an appropriate choice of parameters, which is made possible due to the interplay of inductively and capacitively mediated coupling. Vanishing linear coupling promotes nonlinear effects ranging from onsite- to cross-Kerr interaction. A dominating cross-Kerr interaction related to this configuration is notable, as it induces a unique quantum state. In the course of analog quantum simulations, such elementary building blocks can serve as a precursor for more complex geometries and thus pave the way to a number of novel quantum phases of light
Coupled Resonator Vertical Cavity Laser Diodes
Choquette, K.D.; Chow, W.W.; Fischer, A.J.; Allerman, A.A.; Hou, H.Q.; Geib, K.M.
1999-07-22
For many applications, the device performance of edge emitting semiconductor lasers can be significantly improved through the use of multiple section devices. For example, cleaved coupled cavity (C3) lasers have been shown to provide single mode operation, wavelength tuning, high speed switching, as well as the generation of short pulses via mode-locking and Q-switching [1]. Using composite resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the coupling between the monolithic cavities, incorporate passive or active resonators which are spectrally degenerate or detuned, and to fabricate these devices in 2-dimensional arrays. Composite resonator vertical cavity lasers (CRVCL) have been examined using optical pumping and electrical injection [2-5]. We report on CRVCL diodes and show that efficient modulation of the laser emission can be achieved by either forward or reverse biasing the passive cavity within a CRVCL.
Observation of optomechanical coupling in a microbottle resonator
Asano, Motoki; Chen, Weijian; Özdemir, Şahin Kaya; Ikuta, Rikizo; Imoto, Nobuyuki; Yang, Lan; Yamamoto, Takashi
2016-01-01
In this work, we report optomechanical coupling, resolved sidebands and phonon lasing in a solid-core microbottle resonator fabricated on a single mode optical fiber. Mechanical modes with quality factors (Q_m) as high as 1.57*10^4 and 1.45*10^4 were observed, respectively, at the mechanical frequencies f_m=33.7 MHz and f_m=58.9 MHz. The maximum f_m*Q_m~0.85*10^12 Hz is close to the theoretical lower bound of 6*10^12 Hz needed to overcome thermal decoherence for resolved-sideband cooling of mechanical motion at room temperature, suggesting microbottle resonators as a possible platform for this endeavor. In addition to optomechanical effects, scatter-induced mode splitting and ringing phenomena, which are typical for high-quality optical resonances, were also observed in a microbottle resonator.
Resonances in Coupled-Channel Scattering
Wilson, David J
2016-01-01
Excited hadrons are seen as resonances in the scattering of lighter stable hadrons like $\\pi$, $K$ and $\\eta$. Many decay into multiple final states necessitating coupled-channel analyses. Recently it has become possible to obtain coupled-channel scattering amplitudes from lattice QCD. Using large diverse bases of operators it is possible to obtain reliable finite volume spectra at energies where multiple channels are open. Utilising the finite volume formalism proposed by L\\"uscher and extended by several others, scattering amplitudes can be extracted from the finite volume spectra. Recent applications will be discussed where the energy dependence of scattering amplitudes is mapped out in several quantum numbers. These are then continued to complex energies to extract resonance poles and couplings.
Optical wavelength conversion via optomechanical coupling in a silica resonator
Dong, Chunhua; Kuzyk, Mark C; Tian, Lin; Wang, Hailin
2012-01-01
We report the experimental demonstration of converting coherent optical fields between two different optical wavelengths by coupling two optical modes to a mechanical breathing mode in a silica resonator. The experiment is based on an itinerant approach, in which state-mapping from optical to mechanical and from mechanical to another optical state takes place simultaneously. In contrast to conventional nonlinear optical processes, optomechanical impedance matching as well as efficient optical input-output coupling, instead of phase-matching, plays a crucial role in optomechanics-based wavelength conversion.
Mechanical resonators based on nanotubes and graphene
Bachtold, Adrian
2013-03-01
Carbon nanotubes and graphene offer unique scientific and technological opportunities as nanoelectromechanical systems (NEMS). Namely, they have allowed the fabrication of mechanical resonators that can be operable at ultra-high frequencies and that can be employed as ultra-sensitive sensors of mass and charge. In addition, nanotubes and graphene have exceptional electron transport properties, including ballistic conduction over long distances. Coupling the mechanical motion to electron transport in these remarkable materials is thus highly appealing. Here, I will review some of our recent results on nanotube and graphene NEMSs, including the control of the mechanical oscillation using Coulomb blockade and mass sensing at the proton mass level.
Nonadiabatic dynamics of two strongly coupled nanomechanical resonator modes.
Faust, Thomas; Rieger, Johannes; Seitner, Maximilian J; Krenn, Peter; Kotthaus, Jörg P; Weig, Eva M
2012-07-20
The Landau-Zener transition is a fundamental concept for dynamical quantum systems and has been studied in numerous fields of physics. Here, we present a classical mechanical model system exhibiting analogous behavior using two inversely tunable, strongly coupled modes of the same nanomechanical beam resonator. In the adiabatic limit, the anticrossing between the two modes is observed and the coupling strength extracted. Sweeping an initialized mode across the coupling region allows mapping of the progression from diabatic to adiabatic transitions as a function of the sweep rate.
Scattering by coupled resonating elements in air
Krynkin, Anton; Chong, Alvin Y B; Taherzadeh, Shahram; Attenborough, Keith
2011-01-01
Scattering by (a) a single composite scatterer consisting of a concentric arrangement of an outer N-slit rigid cylinder and an inner cylinder which is either rigid or in the form of a thin elastic shell and (b) by a finite periodic array of these scatterers in air has been investigated analytically and through laboratory experiments. The composite scatterer forms a system of coupled resonators and gives rise to multiple low frequency resonances. The corresponding analytical model employs polar angle dependent boundary conditions on the surface of the N-slit cylinder. The solution inside the slits assumes plane waves. It is shown also that in the low-frequency range the N-slit rigid cylinder can be replaced by an equivalent fluid layer. Further approximations suggest a simple square root dependence of the resonant frequencies on the number of slits and this is confirmed by data. The observed resonant phenomena are associated with Helmholtz-like behaviour of the resonator for which the radius and width of the o...
Optomechanical response of a nonlinear mechanical resonator
Shevchuk, Olga; Singh, Vibhor; Steele, Gary A.; Blanter, Ya. M.
2015-11-01
We investigate theoretically in detail the nonlinear effects in the response of an optical/microwave cavity coupled to a Duffing mechanical resonator. The cavity is driven by a laser at a red or blue mechanical subband, and a probe laser measures the reflection close to the cavity resonance. Under these conditions, we find that the cavity exhibits optomechanically induced reflection (OMIR) or absorption (OMIA) and investigate the optomechanical response in the limit of nonlinear driving of the mechanics. Similar to linear mechanical drive, in an overcoupled cavity the red sideband drive may lead to both OMIA and OMIR depending on the strength of the drive, whereas the blue sideband drive only leads to OMIR. The dynamics of the phase of the mechanical resonator leads to the difference between the shapes of the response of the cavity and the amplitude response of the driven Duffing oscillator, for example, at weak red sideband drive the OMIA dip has no inflection point. We also verify that mechanical nonlinearities beyond Duffing model have little effect on the size of the OMIA dip though they affect the width of the dip.
CROSSING A COUPLING SPIN RESONANCE WITH AN RF DIPOLE.
BAI,M.; ROSER,T.
2001-06-18
In accelerators, due to quadrupole roll errors and solenoid fields, the polarized proton acceleration often encounters coupling spin resonances. In the Brookhaven AGS, the coupling effect comes from the solenoid partial snake which is used to overcome imperfection resonances. The coupling spin resonance strength is proportional to the amount of coupling as well as the strength of the corresponding intrinsic spin resonance. The coupling resonance can cause substantial beam polarization loss if its corresponding intrinsic spin resonance is very strong. A new method of using an horizontal rf dipole to induce a full spin flip crossing both the intrinsic and its coupling spin resonances is studied in the Brookhaven's AGS. Numerical simulations show that a full spin flip can be induced after crossing the two resonances by using a horizontal rf dipole to induce a large vertical coherent oscillation.
Aspects of stochastic resonance in Josephson junction, bimodal maps and coupled map lattice
G Ambika; Kamala Menon; K P Harikrishnan
2005-04-01
We present the results of extensive numerical studies on stochastic resonance and its characteristic features in three model systems, namely, a model for Josephson tunnel junctions, the bistable cubic map and a coupled map lattice formed by coupling the cubic maps. Some interesting features regarding the mechanism including multisignal amplification and spatial stochastic resonance are shown.
Axion Dark Matter Coupling to Resonant Photons via Magnetic Field.
McAllister, Ben T; Parker, Stephen R; Tobar, Michael E
2016-04-22
We show that the magnetic component of the photon field produced by dark matter axions via the two-photon coupling mechanism in a Sikivie haloscope is an important parameter passed over in previous analysis and experiments. The interaction of the produced photons will be resonantly enhanced as long as they couple to the electric or magnetic mode structure of the haloscope cavity. For typical haloscope experiments the electric and magnetic couplings are equal, and this has implicitly been assumed in past sensitivity calculations. However, for future planned searches such as those at high frequency, which synchronize multiple cavities, the sensitivity will be altered due to different magnetic and electric couplings. We define the complete electromagnetic form factor and discuss its implications for current and future dark matter axion searches over a wide range of masses.
Plasmonic metamaterial absorber for broadband manipulation of mechanical resonances
Zhu, Hai; Yi, Fei; Cubukcu, Ertugrul
2016-11-01
Metamaterials are artificial materials that exhibit unusual properties for electromagnetic and sound waves. The quanta, namely photons and phonons, of these waves interact resonantly with these exotic man-made materials enabling many applications. For instance, resonant light absorption in photonic metamaterials can efficiently convert optical energy into heat based on the photothermal effect. Here, we present a plasmonic metamaterial that simultaneously supports thermomechanically coupled optical and mechanical resonances for controlling mechanical damping with light. In this metamaterial absorber with voltage-tunable Fano resonances, we experimentally achieve optically pumped coherent mechanical oscillations based on a plasmomechanical parametric gain mechanism over an ∼4 THz bandwidth. Through the reverse effect, optical damping of mechanical resonance is also achieved. Our results provide a metamaterial-based approach for optical manipulation of the dynamics of mechanical oscillators.
Wide dynamic range microwave planar coupled ring resonator for sensing applications
Zarifi, Mohammad Hossein; Daneshmand, Mojgan
2016-06-01
A highly sensitive, microwave-coupled ring resonator with a wide dynamic range is studied for use in sensing applications. The resonator's structure has two resonant rings and, consequently, two resonant frequencies, operating at 2.3 and 2.45 GHz. Inductive and capacitive coupling mechanisms are explored and compared to study their sensing performance. Primary finite element analysis and measurement results are used to compare the capacitive and inductive coupled ring resonators, demonstrating sensitivity improvements of up to 75% and dynamic range enhancement up to 100% in the capacitive coupled structure. In this work, we are proposing capacitive coupled planar ring resonators as a wide dynamic range sensing platform for liquid sensing applications. This sensing device is well suited for low-cost, real-time low-power, and CMOS compatible sensing technologies.
Signal-flow graphs in coupled laser resonator analysis
Pedersen, Christian; Skettrup, Torben
1997-01-01
Signal-flow graph analysis of coupled linear systems is introduced in order to find a simple method to treat systems of coupled optical resonators. The proposed method turns out to be well suited for this purpose, and the reflectance and transmittance of coupled resonator systems are easily found...
Saeed Mohammadi
2011-12-01
Full Text Available In this paper, we report the evidence for the possibility of achieving complex signal processing functionalities such as multiplexing/demultiplexing at high frequencies using phononic crystal (PnC slabs. It is shown that such functionalities can be obtained by appropriate cross-coupling of PnC resonators and waveguides. PnC waveguides and waveguide-based resonators are realized and cross-coupled through two different methods of mechanical coupling (i.e., direct coupling and side coupling. Waveguide-based PnC resonators are employed because of their high-Q, compactness, large spurious-free spectral ranges, and the possibility of better control over coupling to PnC waveguides. It is shown that by modifying the defects in the formation of the resonators, the frequency of the resonance can be tuned.
Coupled-channels optical calculation of positron-hydrogen resonances
Yu Rong-Mei; Zhou Ya-Jun; Jiao Li-Guang; Cheng Yong-Jun
2012-01-01
An application of the coupled-channels optical method is given for the energy-dependent phenomena of positronhydrogen resonances below the n =2 excitation threshold.The equivalent local optical potential is used to account for the target polarization and positronium formation.The calculation includes 9 explicitly physical coupled channels.The lowest S-wave resonance energy position and new resonances are found.Angular dependence of the cross section in the resonance region are investigated.
Analyzing a Vibrating Wire Transducer using Coupled Resonator Circuits
POP, S.
2015-08-01
Full Text Available This paper intends to be an approach on the vibrating wire transducer from the perspective of the necessary rules used for a correct measurement procedure. There are several studies which analyze the vibrating wire transducer as a mechanical system. However, a comparative time-domain analysis between the mechanical and the electrical model is lacking. The transducer analysis is based on a theoretical analysis of the equivalent circuit, on both excitation and response time intervals. The electrical model consists of two magnetic coupled resonating circuits. When connected to an excitation source, there will be an energy transfer from the coil to the wire. The maximum energy transfer will occur at the vibrating wire's frequency of resonance. Using the transient regime analysis, it has been proven that, in the response time interval - when the wire vibrates freely, the current through the circuit that models the wire describes the oscillating movement of the wire. A complex signal is obtained, that contains both coil's and wire's frequencies of resonance, strongly dependent with theirs parasitic elements. The mathematical analysis highlights the similarity between mechanical and electrical model and the procedures in order to determine the wire frequency of resonance from the output signal.
Wireless Power Transmission Using Resonance Inductive Coupling
Prof. Vishal V. Pande,
2014-04-01
Full Text Available In this paper, we present the concept of transmitting power without using wires i.e.transmitting power as Magnetic waves from one place to another is in order to reduce the transmission and distribution losses. This concept is known as Resonance Inductive Coupling (RIC. We also discussed the technological developments in Wireless Power Transmission (WPT. The advantages, disadvantages, biological impacts and applications of WPT are also presented. Wireless power or wireless energy transmission is the transmission of electrical energy from a power source to an electrical load without man-made conductors. Wireless transmission is useful in cases where interconnecting wires are inconvenient, hazardous, or impossible. the proportion of energy received becomes critical only if it is too low for the signal to be distinguished from the background noise. With wireless power, efficiency is the more significant parameter. A large part of the energy sent out by the generating plant must arrive at the receiver or receivers to make the system economical.The most common form of wireless power transmission is carried out using direct induction followed by resonant magnetic induction. Other methods under consideration are electromagnetic radiation in the form of microwaves or lasers and electrical conduction through natural media
Observation of generalized optomechanical coupling and cooling on cavity resonance.
Sawadsky, Andreas; Kaufer, Henning; Nia, Ramon Moghadas; Tarabrin, Sergey P; Khalili, Farid Ya; Hammerer, Klemens; Schnabel, Roman
2015-01-30
Optomechanical coupling between a light field and the motion of a cavity mirror via radiation pressure plays an important role for the exploration of macroscopic quantum physics and for the detection of gravitational waves (GWs). It has been used to cool mechanical oscillators into their quantum ground states and has been considered to boost the sensitivity of GW detectors, e.g., via the optical spring effect. Here, we present the experimental characterization of generalized, that is, dispersive and dissipative, optomechanical coupling, with a macroscopic (1.5 mm)2-size silicon nitride membrane in a cavity-enhanced Michelson-type interferometer. We report for the first time strong optomechanical cooling based on dissipative coupling, even on cavity resonance, in excellent agreement with theory. Our result will allow for new experimental regimes in macroscopic quantum physics and GW detection.
Observation of generalized optomechanical coupling and cooling on cavity resonance
Sawadsky, Andreas; Nia, Ramon Moghadas; Tarabrin, Sergey P; Khalili, Farid Ya; Hammerer, Klemens; Schnabel, Roman
2014-01-01
Optomechanical coupling between a light field and the motion of a cavity mirror via radiation pressure plays an important role for the exploration of macroscopic quantum physics and for the detection of gravitational waves (GWs). It has been used to cool mechanical oscillators into their quantum ground states and has been considered to boost the sensitivity of GW detectors, e.g. via the optical spring effect. Here, we present the experimental characterization of generalized, that is, dispersive and dissipative optomechanical coupling, with a macroscopic (1.5mm)^2-sized silicon nitride (SiN) membrane in a cavity-enhanced Michelson-type interferometer. We report for the first time strong optomechanical cooling based on dissipative coupling, even on cavity resonance, in excellent agreement with theory. Our result will allow for new experimental regimes in macroscopic quantum physics and GW detection.
Tailored Asymmetry for Enhanced Coupling to WGM Resonators
Mohageg, Makan; Maleki, Lute
2008-01-01
Coupling of light into and out of whispering- gallery-mode (WGM) optical resonators can be enhanced by designing and fabricating the resonators to have certain non-axisymmetric shapes (see figure). Such WGM resonators also exhibit the same ultrahigh values of the resonance quality factor (Q) as do prior WGM resonators. These WGM resonators are potentially useful as tunable narrow-band optical filters having throughput levels near unity, high-speed optical switches, and low-threshold laser resonators. These WGM resonators could also be used in experiments to investigate coupling between high-Q and chaotic modes within the resonators. For a WGM resonator made of an optically nonlinear material (e.g., lithium niobate) or another material having a high index of refraction, a prism made of a material having a higher index of refraction (e.g., diamond) must be used as part of the coupling optics. For coupling of a beam of light into (or out of) the high-Q resonator modes, the beam must be made to approach (or recede from) the resonator at a critical angle determined by the indices of refraction of the resonator and prism materials. In the case of a lithium niobate/diamond interface, this angle is approximately 22 .
Quantum communication between remote mechanical resonators
Felicetti, S.; Fedortchenko, S.; Rossi, R.; Ducci, S.; Favero, I.; Coudreau, T.; Milman, P.
2017-02-01
Mechanical resonators represent one of the most promising candidates to mediate the interaction between different quantum technologies, bridging the gap between efficient quantum computation and long-distance quantum communication. Here, we introduce an interferometric scheme where the interaction of a mechanical resonator with input-output quantum pulses is controlled by an independent classical drive. We design protocols for state teleportation and direct quantum state transfer, between distant mechanical resonators. The proposed device, feasible with state-of-the-art technology, can serve as a building block for the implementation of long-distance quantum networks of mechanical resonators.
Resonator coupled Josephson junctions; parametric excitations and mutual locking
Jensen, H. Dalsgaard; Larsen, A.; Mygind, Jesper
1991-01-01
Self-pumped parametric excitations and mutual locking in systems of Josephson tunnel junctions coupled to multimode resonators are reported. For the very large values of the coupling parameter, obtained with small Nb-Al2O3-Nb junctions integrated in superconducting microstrip resonators, the DC I......-V characteristic shows an equidistant series of current steps generated by subharmonic pumping of the fundamental resonator mode. This is confirmed by measurement of frequency and linewidth of the emitted Josephson radiation...
COMPACT INTERLOCKED-COUPLED FILTER USING FOLDED STEPPED-IMPEDANCE RESONATORS
Chen Chunhong; Wu Wen; Wu Hongmei
2012-01-01
A microstrip interlocked-coupled bandpass filter is proposed with a markedly compact structure.The low-impedance open-end line of the quarter-wavelength Stepped-Impedance Resonator (SIR) is replaced by two open-end high-impedance lines,which not only facilitate the coupling mechanism but also provide the strong electric coupling between resonators.With the proper utilization of folded SIRs,the occupied area of coupled-resonator pair can be reduced.By applying the proposed coupled-resonator pair,the passband filter with the compact size can be realized.Good agreement between measured and simulated results is observed.The proposed filter is desirable for compact and high-performance microwave circuit applications.
Probing Mechanical Resonances in Cantilevered Coiled Carbon Nanowires
Saini, Deepika; Dickel, Doyl; Behlow, Herbert; Pillai, Balu; Yang, Keqin; Skove, Malcolm; Serkiz, Steven; Rao, Apparao; Clemson University Team; Savannah River National Laboratory Team
2013-03-01
Helically coiled carbon nanowires (CCNW) and nanotubes are promising elements for use in MEMS/NEMS devices and nanorobotics, as nano-inductors and sensors, and for impact protection (e.g. Bell et al. 2007 IEEE International Conference, J. Appl. Phys. 100, 064309 (2006)). Understanding and characterizing their mechanical resonance behavior is essential for the reliability in applications. In this study, we have electrically actuated an individual CCNW in a diving-board cantilever configuration inside a scanning electron microscope, and electrically detected its mechanical resonance modes. By oscillation at low frequency we confirmed the induced-charge actuation mechanism. Among the modes we observed, some appeared to have both axial and lateral components. We also observed closely spaced resonance modes which we attribute to the splitting of degenerate modes, consistent with our COMSOL simulations. We suggest that the helical morphology facilitates inter-mode coupling that results in the observed complex resonance behavior.
Integrating out resonances in strongly-coupled electroweak scenarios
Rosell, Ignasi; Santos, Joaquin; Sanz-Cillero, Juan Jose
2016-01-01
Accepting that there is a mass gap above the electroweak scale, the Electroweak Effective Theory (EWET) is an appropriate tool to describe this situation. Since the EWET couplings contain information on the unknown high-energy dynamics, we consider a generic strongly-coupled scenario of electroweak symmetry breaking, where the known particle fields are coupled to heavier states. Then, and by integrating out these heavy fields, we study the tracks of the lightest resonances into the couplings. The determination of the low-energy couplings (LECs) in terms of resonance parameters can be made more precise by considering a proper short-distance behaviour on the Lagrangian with heavy states, since the number of resonance couplings is then reduced. Notice that we adopt a generic non-linear realization of the electroweak symmetry breaking with a singlet Higgs.
Optimisation Design of Coupling Region Based on SOI Micro-Ring Resonator
Shubin Yan
2014-12-01
Full Text Available Design optimization of the coupling region is conducted in order to solve the difficulty of achieving a higher quality factor (Q for large size resonators based on silicon-on-insulator (SOI. Relations among coupling length, coupling ratio and quality factor of the optical cavities are theoretically analyzed. Resonators (R = 100 μm with different coupling styles, concentric, straight, and butterfly, are prepared by the micro-electro-mechanical-systems (MEMS process. Coupling experimental results show that micro-cavity of butterfly-coupled style obtains the narrowest (3 dB bandwidth, and the quality factor has been greatly improved. The results provide the foundation for realization of a large size, high-Q resonator, and its development and application in the integrated optical gyroscopes, filters, sensors, and other related fields.
The dynamics of large-scale arrays of coupled resonators
Borra, Chaitanya; Pyles, Conor S.; Wetherton, Blake A.; Quinn, D. Dane; Rhoads, Jeffrey F.
2017-03-01
This work describes an analytical framework suitable for the analysis of large-scale arrays of coupled resonators, including those which feature amplitude and phase dynamics, inherent element-level parameter variation, nonlinearity, and/or noise. In particular, this analysis allows for the consideration of coupled systems in which the number of individual resonators is large, extending as far as the continuum limit corresponding to an infinite number of resonators. Moreover, this framework permits analytical predictions for the amplitude and phase dynamics of such systems. The utility of this analytical methodology is explored through the analysis of a system of N non-identical resonators with global coupling, including both reactive and dissipative components, physically motivated by an electromagnetically-transduced microresonator array. In addition to the amplitude and phase dynamics, the behavior of the system as the number of resonators varies is investigated and the convergence of the discrete system to the infinite-N limit is characterized.
Spectral Engineering with Coupled Microcavities: Active Control of Resonant Mode-Splitting
Souza, Mario C M M; Barea, Luis A M; von Zuben, Antonio A G; Wiederhecker, Gustavo S; Frateschi, Newton C
2015-01-01
Optical mode-splitting is an efficient tool to shape and fine-tune the spectral response of resonant nanophotonic devices. The active control of mode-splitting, however, is either small or accompanied by undesired resonance shifts, often much larger than the resonance-splitting. We report a control mechanism that enables reconfigurable and widely tunable mode-splitting while efficiently mitigating undesired resonance shifts. This is achieved by actively controlling the excitation of counter-traveling modes in coupled resonators. The transition from a large splitting (80 GHz) to a single-notch resonance is demonstrated using low power microheaters (35 mW). We show that the spurious resonance-shift in our device is only limited by thermal crosstalk and resonance-shift-free splitting control may be achieved.
Stochastic Resonance in a Coupled Array Without Periodic Driving
钱敏; 张雪娟
2002-01-01
We manifest a stochastic resonance in a two-dimensional square array of coupled oscillators subjected only to white noise and constant driving forces. The result shows that the coherent output of every single oscillator plays the role of periodic input to its neighbours. Even without periodic driving, the cooperation of the white noise and the coupling can also result in the array enhanced stochastic resonance effect. In our investigation, global as well as local noise perturbation is taken into account.
Indirect Coupling between Two Cavity Photon Systems via Ferromagnetic Resonance
Hyde, Paul; Harder, Michael; Match, Christophe; Hu, Can-Ming
2016-01-01
We experimentally realize indirect coupling between two cavity modes via strong coupling with the ferromagnetic resonance in Yttrium Iron Garnet (YIG). We find that some indirectly coupled modes of our system can have a higher microwave transmission than the individual uncoupled modes. Using a coupled harmonic oscillator model, the influence of the oscillation phase difference between the two cavity modes on the nature of the indirect coupling is revealed. These indirectly coupled microwave modes can be controlled using an external magnetic field or by tuning the cavity height. This work has potential for use in controllable optical devices and information processing technologies.
Monitoring microbial metabolites using an inductively coupled resonance circuit
Karnaushenko, Daniil; Baraban, Larysa; Ye, Dan; Uguz, Ilke; Mendes, Rafael G.; Rümmeli, Mark H.; Visser, de Arjan; Schmidt, Oliver G.; Cuniberti, Gianaurelio; Makarov, Denys
2015-01-01
We present a new approach to monitor microbial population dynamics in emulsion droplets via changes in metabolite composition, using an inductively coupled LC resonance circuit. The signal measured by such resonance detector provides information on the magnetic field interaction with the bacteria
Mode couplings and resonance instabilities in dust clusters.
Qiao, Ke; Kong, Jie; Oeveren, Eric Van; Matthews, Lorin S; Hyde, Truell W
2013-10-01
The normal modes for three to seven particle two-dimensional (2D) dust clusters in a complex plasma are investigated using an N-body simulation. The ion wakefield downstream of each particle is shown to induce coupling between horizontal and vertical modes. The rules of mode coupling are investigated by classifying the mode eigenvectors employing the Bessel and trigonometric functions indexed by order integers (m, n). It is shown that coupling only occurs between two modes with the same m and that horizontal modes having a higher shear contribution exhibit weaker coupling. Three types of resonances are shown to occur when two coupled modes have the same frequency. Discrete instabilities caused by both the first and third type of resonances are verified and instabilities caused by the third type of resonance are found to induce melting. The melting procedure is observed to go through a two-step process with the solid-liquid transition closely obeying the Lindemann criterion.
A Coupled Resonator for Highly Tunable and Amplified Mixer/Filter
Ilyas, Saad
2017-04-25
We present an H-shaped resonator made of two clamped-clamped microbeams mechanically coupled at the middle with a strong coupler to achieve, in a single device, mechanical amplification of the response signal, filtering, and frequency conversion simultaneously. Using mechanical amplification combined with combination resonances generated from a mixed-frequency excitation, a wideband tunable filter, and a simultaneous frequency up and down convertors at multiple bands is demonstrated. The proposed coupled structure, when combined with the easy-to-implement technique of frequency mixing, is promising for applications in an RF chain.
Tunable band notch filters by manipulating couplings of split ring resonators.
Sun, Haibin; Wen, Guangjun; Huang, Yongjun; Li, Jian; Zhu, Weiren; Si, Li-Ming
2013-11-01
The couplings between single/dual split ring resonators (SRRs) and their mirror images in a rectangular waveguide are systematically investigated through theoretical analysis and experimental measurements. Such couplings can be manipulated mechanically by rotating the SRRs along a dielectric rod and/or shifting the SRRs up/down along the sidewall of the rectangular waveguide, resulting in shifts of the resonant frequencies and modulations of the resonant magnitudes. These controllable properties of SRRs pave the routers toward designing tunable band notch filters. In particular, it is experimentally demonstrated that the designed filters possess 7.5% tuning range in the X-band.
Enhanced acoustoelectric coupling in acoustic energy harvester using dual Helmholtz resonators.
Peng, Xiao; Wen, Yumei; Li, Ping; Yang, Aichao; Bai, Xiaoling
2013-10-01
In this paper, enhanced acoustoelectric transduction in an acoustic energy harvester using dual Helmholtz resonators has been reported. The harvester uses a pair of cavities mechanically coupled with a compliant perforated plate to enhance the acoustic coupling between the cavity and the plate. The experimental results show that the volume optimization of the second cavity can significantly increase the generated electric voltage up to 400% and raise the output power to 16 times as large as that of a harvester using a single Helmholtz resonator at resonant frequencies primarily related to the plate.
Electric and magnetic dipole couplings in split ring resonator metamaterials
Fan Jing; Sun Guang-Yong; and Zhu Wei-Ren
2011-01-01
In this paper,the electric and the magnetic dipole couplings between the outer and the inner rings of a single split ring resonator (SRR) are investigated.We numerically demonstrate that the magnetic resonance frequency can be substantially modified by changing the couplings of the electric and magnetic dipoles,and give a theoretical expression of the magnetic resonance frequency.The results in this work are expected to be conducive to a deeper understanding of the SRR and other similar metamaterials,and provide new guidance for complex metamaterials design with a tailored electromagnetic response.
Fiber-coupled short Fabry-Perot resonators
Stone, J.; Marcuse, D. (AT and T Bell Labs., Holmdel, NJ (USA))
1989-05-01
Fabry-Perot resonators intended as filters in wavelength-multiplexed optical communications systems may have to be very short (on the order of 10 {mu}m) in order to increase their free spectral range. Short, yet tunable cavities can be designed as air gaps between two fibers placed in close proximity with highly reflecting mirrors deposited on their ends. However, an air-gap resonator with plane mirrors between closely spaced fiber ends may yield low throughout because of the poor match between the modes of typical single-mode fibers and the resonant mode in the air-gap cavity. The throughput can be improved by confining the resonant mode by means of a hollow dielectric tube placed inside the resonator. This paper compares short fiber-coupled Fabry-Parot resonators with and without an inserted hollow dielectric waveguide and derives expressions for their transmission losses. The authors show that the throughput of both types of resonator can be improved significantly by using a special fiber with large mode size to couple to the resonator. The special fiber is then spliced to a conventional single-mode fiber. They conclude that the resonator with an inserted hollow dielectric waveguide offers increased throughput for resonators with high finesse.
Negative coupling and coupling phase dispersion in a silicon quadrupole micro-racetrack resonator.
Bachman, Daniel; Tsay, Alan; Van, Vien
2015-07-27
We report the first experimental study of the effects of coupling phase dispersion on the spectral response of a two-dimensionally coupled quadrupole micro-racetrack resonator. Negative coupling in the system is observed to manifest itself in the sharp stop band transition and deep extinction in the pseudo-elliptic filter response of the quadrupole. The results demonstrate the feasibility of realizing advanced silicon microring devices based on the 2D coupling topology with general complex coupling coefficients.
Resonant coupling of a Bose-Einstein condensate to a micromechanical oscillator
Hunger, D; Haensch, T W; Koenig, D; Kotthaus, J P; Reichel, J; Treutlein, P
2010-01-01
We report experiments in which the vibrations of a micromechanical oscillator are coupled to the motion of Bose-condensed atoms in a trap. The interaction relies on surface forces experienced by the atoms at about one micrometer distance from the mechanical structure. We observe resonant coupling to several well-resolved mechanical modes of the condensate. Coupling via surface forces does not require magnets, electrodes, or mirrors on the oscillator and could thus be employed to couple atoms to molecular-scale oscillators such as carbon nanotubes.
A resonance mechanism of earthquakes
Flambaum, V V
2015-01-01
It had been observed in [1] that there are periodic 4-6 hours pulses of ? 200 ?Hz seismogravita- tional oscillations ( SGO ) before 95 % of powerful earthquakes. We explain this by beating between an oscillation eigenmode of a whole tectonic plate and a local eigenmode of an active zone which tranfers the oscillation energy from the tectonic plate to the active zone causing the eathrquake. Oscillation frequencies of the plate and ones of the active zone are tuned to a resonance by an additional pressure applied to the active zone due to collision of neighboring plates or convection in the upper mantia (plume). Corresponding theory may be used for short-term prediction of the earthquakes and tsunami.
Waveguide coupled resonance fluorescence from on-chip quantum emitter.
Makhonin, Maxim N; Dixon, James E; Coles, Rikki J; Royall, Ben; Luxmoore, Isaac J; Clarke, Edmund; Hugues, Maxime; Skolnick, Maurice S; Fox, A Mark
2014-12-10
Resonantly driven quantum emitters offer a very promising route to obtain highly coherent sources of single photons required for applications in quantum information processing (QIP). Realizing this for on-chip scalable devices would be important for scientific advances and practical applications in the field of integrated quantum optics. Here we report on-chip quantum dot (QD) resonance fluorescence (RF) efficiently coupled into a single-mode waveguide, a key component of a photonic integrated circuit, with a negligible resonant laser background and show that the QD coherence is enhanced by more than a factor of 4 compared to off-resonant excitation. Single-photon behavior is confirmed under resonant excitation, and fast fluctuating charge dynamics are revealed in autocorrelation g((2)) measurements. The potential for triggered operation is verified in pulsed RF. These results pave the way to a novel class of integrated quantum-optical devices for on-chip quantum information processing with embedded resonantly driven quantum emitters.
Static and Dynamic Amplification Using Strong Mechanical Coupling
Ilyas, Saad
2016-07-28
Amplifying the signal-to-noise ratio of resonant sensors is vital toward the effort to miniaturize devices into the sub-micro and nano regimes. In this paper, we demonstrate theoretically and experimentally, amplification through mechanically coupled microbeams. The device is composed of two identical clamped-clamped beams, made of polyimide, connected at their middle through a third beam, which acts as a mechanical coupler. Each of the clamped-clamped microbeams and the coupler are designed to be actuated separately, hence providing various possibilities of actuation and sensing. The coupled resonator is driven into resonance near its first resonance mode and its dynamic behavior is explored via frequency sweeps. The results show significant amplification in the resonator amplitude when the signal is measured at the midpoint of the coupler compared with the response of the individual uncoupled beams. The static pull-in characteristics of the resonator are also studied. It is shown that the compliant mechanical coupler can serve as a low-power radio frequency switch actuated at low voltage loads. [2016-0100
Yue Tang
2017-04-01
Full Text Available A surface plasmon polariton refractive index sensor based on Fano resonances in metal–insulator–metal (MIM waveguides coupled with rectangular and ring resonators is proposed and numerically investigated using a finite element method. Fano resonances are observed in the transmission spectra, which result from the coupling between the narrow-band spectral response in the ring resonator and the broadband spectral response in the rectangular resonator. Results are analyzed using coupled-mode theory based on transmission line theory. The coupled mode theory is employed to explain the Fano resonance effect, and the analytical result is in good agreement with the simulation result. The results show that with an increase in the refractive index of the fill dielectric material in the slot of the system, the Fano resonance peak exhibits a remarkable red shift, and the highest value of sensitivity (S is 1125 nm/RIU, RIU means refractive index unit. Furthermore, the coupled MIM waveguide structure can be integrated with other photonic devices at the chip scale. The results can provide a guide for future applications of this structure.
Ramos, Daniel, E-mail: daniel.ramos@csic.es; Frank, Ian W.; Deotare, Parag B.; Bulu, Irfan; Lončar, Marko [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States)
2014-11-03
We investigate the coupling between mechanical and optical modes supported by coupled, freestanding, photonic crystal nanobeam cavities. We show that localized cavity modes for a given gap between the nanobeams provide weak optomechanical coupling with out-of-plane mechanical modes. However, we show that the coupling can be significantly increased, more than an order of magnitude for the symmetric mechanical mode, due to optical resonances that arise from the interaction of the localized cavity modes with standing waves formed by the reflection from thesubstrate. Finally, amplification of motion for the symmetric mode has been observed and attributed to the strong optomechanical interaction of our hybrid system. The amplitude of these self-sustained oscillations is large enough to put the system into a non-linear oscillation regime where a mixing between the mechanical modes is experimentally observed and theoretically explained.
Control of critical coupling in a coiled coaxial cable resonator.
Huang, Jie; Wei, Tao; Wang, Tao; Fan, Jun; Xiao, Hai
2014-05-01
This paper reports a coiled coaxial cable resonator fabricated by cutting a slot in a spring-like coiled coaxial cable to produce a periodic perturbation. Electromagnetic coupling between two neighboring slots was observed. By manipulating the number of slots, critical coupling of the coiled coaxial cable resonator can be well controlled. An ultrahigh signal-to-noise ratio (over 50 dB) at the resonant frequency band was experimentally achieved from a coiled coaxial cable resonator with 38 turns. A theoretic model is developed to understand the device physics. The proposed device can be potentially used as a high quality and flexibly designed band-stop filter or a sensor in structural health monitoring.
Energy Harvesting with Coupled Magnetorestrictive Resonators
2013-09-01
Guyomar, and B. Ducharne. 2011. “Simulation of a Duffing Oscillator for Broadband Piezoelectric Energy Harvesting,” Smart Materials and Structures, vol...electromagnetic technique includes suspended magnets in a coil or a suspended coil in a magnet array that oscillates as it is excited with vibrational motion...coupled systems of non-linear oscillators improve the performance of sensors by increasing sensitivity [1]. This concept can be used to harvest more
Resonance features of coupled Josephson junctions: radiation and shunting
Shukrinov, Yu M.; Seidel, P.; Il'ichev, E.; Nawrocki, W.; Grajcar, M.; Plecenik, P. A.; Rahmonov, I. R.; Kulikov, K.
2012-11-01
We study the phase dynamics and the resonance features of coupled Josephson junctions in layered superconductors and their manifestations in the current- voltage characteristics and temporal dependence of the electric charge in the superconducting layers. Results on the effect of the external radiation and shunting of the stack of Josephson junctions by LC-elements are presented. We discuss the ideas concerning the experimental observation of these resonances.
Strong Coupling between On Chip Notched Ring Resonator and Nanoparticle
Wang, S; Smith, H; Yi, Y
2010-01-01
We have demonstrated a new photonic structure to achieve strong optical coupling between nanoparticle and photonic molecule by utilizing a notched micro ring resonators. By creating a notch in the ring resonator and putting a nanoparticle inside the notch, large spectral shifts and splittings at nm scale can be achieved, compared to only pm scale observed by fiber tip evanescently coupled to the surface of microsphere, thereby significantly lowered the quality factor requirement for single nanoparticle detection. The ability for sorting the type of nanoparticles due to very different mode shift and splitting behavior of dielectric and metallic nanoparticles is also emphasized.
Resonance-enhanced optical forces between coupled photonic crystal slabs.
Liu, Victor; Povinelli, Michelle; Fan, Shanhui
2009-11-23
The behaviors of lateral and normal optical forces between coupled photonic crystal slabs are analyzed. We show that the optical force is periodic with displacement, resulting in stable and unstable equilibrium positions. Moreover, the forces are strongly enhanced by guided resonances of the coupled slabs. Such enhancement is particularly prominent near dark states of the system, and the enhancement effect is strongly dependent on the types of guided resonances involved. These structures lead to enhancement of light-induced pressure over larger areas, in a configuration that is directly accessible to externally incident, free-space optical beams.
Elnaggar, Sameh Y. [School of Engineering and Information Technology, University of New South Wales, Canberra (Australia); Tervo, Richard J. [Department of Electrical and Computer Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3 Canada (Canada); Mattar, Saba M., E-mail: mattar@unb.ca [Chemistry Department, University of New Brunswick, Fredericton, NB, E3B 5A3 Canada (Canada)
2015-11-21
The theory and operation of various devices and systems, such as wireless power transfer via magnetic resonant coupling, magneto-inductive wave devices, magnetic resonance spectroscopy probes, and metamaterials can rely on coupled tuned resonators. The coupling strength is usually expressed in terms of the coupling coefficient κ, which can have electrical κ{sub E} and/or magnetic κ{sub M} components. In the current article, general expressions of κ are derived. The relation between the complex Poynting equation in its microscopic form and κ is made and discussed in detail. It is shown that κ can be expressed in terms of the interaction energy between the resonators' modes. It thus provides a general form that combines the magnetic and electric components of κ. The expressions make it possible to estimate the frequencies and fields of the coupled modes for arbitrarily oriented and spaced resonators. Thus, enabling the calculation of system specific parameters such as the transfer efficiency of wireless power transfer systems, resonator efficiency for electron spin resonance probes, and dispersion relations of magneto-inductive and stereo-metamaterials structures.
Characterization of complementary electric field coupled resonant surfaces
Hand, Thomas H.; Gollub, Jonah; Sajuyigbe, Soji; Smith, David R.; Cummer, Steven A.
2008-11-01
We present angle-resolved free-space transmission and reflection measurements of a surface composed of complementary electric inductive-capacitive (CELC) resonators. By measuring the reflection and transmission coefficients of a CELC surface with different polarizations and particle orientations, we show that the CELC only responds to in-plane magnetic fields. This confirms the Babinet particle duality between the CELC and its complement, the electric field coupled LC resonator. Characterization of the CELC structure serves to expand the current library of resonant elements metamaterial designers can draw upon to make unique materials and surfaces.
Anomalous couplings, resonances and unitarity in vector boson scattering
Sekulla, Marco
2015-12-04
The Standard Model of particle physics has proved itself as a reliable theory to describe interactions of elementary particles. However, many questions concerning the Higgs sector and the associated electroweak symmetry breaking are still open, even after (or because) a light Higgs boson has been discovered. The 2→2 scattering amplitude of weak vector bosons is suppressed in the Standard Model due to the Higgs boson exchange. Therefore, weak vector boson scattering processes are very sensitive to additional contributions beyond the Standard Model. Possible new physics deviations can be studied model-independently by higher dimensional operators within the effective field theory framework. In this thesis, a complete set of dimension six and eight operators are discussed for vector boson scattering processes. Assuming a scenario where new physics in the Higgs/Goldstone boson decouples from the fermion-sector and the gauge-sector in the high energy limit, the impact of the dimension six operator L{sub HD} and dimension eight operators L{sub S,0} and L{sub S,1} to vector boson scattering processes can be studied separately for complete processes at particle colliders. However, a conventional effective field theory analysis will violate the S-matrix unitarity above a certain energy limit. The direct T-matrix scheme is developed to allow a study of effective field theory operators consistent with basic quantum-mechanical principles in the complete energy reach of current and future colliders. Additionally, this scheme can be used preventively for any model, because it leaves theoretical predictions invariant, which already satisfies unitarity. The effective field theory approach is further extended by allowing additional generic resonances coupling to the Higgs/Goldstone boson sector, namely the isoscalar-scalar, isoscalar-tensor, isotensor-scalar and isotensor-tensor. In particular, the Stueckelberg formalism is used to investigate the impact of the tensor degree of
Resonant excitation of coupled skyrmions by spin-transfer torque
Dai, Y. Y.; Wang, H.; Yang, T.; Zhang, Z. D.
2016-12-01
Resonant excitations of coupled skyrmions in Co/Ru/Co nanodisks activated by spin-transfer torque (STT) have been studied by micromagnetic simulations. It is found that STT is an effective method to manipulate skyrmion dynamics. Unlike the dynamics driven by a microwave field, two skyrmions with opposite chiralities move synchronously in the same direction when they are driven by STT, which makes it easier to observe the dynamics of coupled skyrmions in experiments. Resonant excitations of coupled skyrmions can be controlled by changing the frequency or amplitude ratio of a dual-frequency alternating current (AC). In addition, the magnetostatic interaction between the two skyrmions plays an important role in the dynamics of coupled skyrmions.
Parameters optimization for magnetic resonance coupling wireless power transmission.
Li, Changsheng; Zhang, He; Jiang, Xiaohua
2014-01-01
Taking maximum power transmission and power stable transmission as research objectives, optimal design for the wireless power transmission system based on magnetic resonance coupling is carried out in this paper. Firstly, based on the mutual coupling model, mathematical expressions of optimal coupling coefficients for the maximum power transmission target are deduced. Whereafter, methods of enhancing power transmission stability based on parameters optimal design are investigated. It is found that the sensitivity of the load power to the transmission parameters can be reduced and the power transmission stability can be enhanced by improving the system resonance frequency or coupling coefficient between the driving/pick-up coil and the transmission/receiving coil. Experiment results are well conformed to the theoretical analysis conclusions.
Parameters Optimization for Magnetic Resonance Coupling Wireless Power Transmission
Changsheng Li
2014-01-01
Full Text Available Taking maximum power transmission and power stable transmission as research objectives, optimal design for the wireless power transmission system based on magnetic resonance coupling is carried out in this paper. Firstly, based on the mutual coupling model, mathematical expressions of optimal coupling coefficients for the maximum power transmission target are deduced. Whereafter, methods of enhancing power transmission stability based on parameters optimal design are investigated. It is found that the sensitivity of the load power to the transmission parameters can be reduced and the power transmission stability can be enhanced by improving the system resonance frequency or coupling coefficient between the driving/pick-up coil and the transmission/receiving coil. Experiment results are well conformed to the theoretical analysis conclusions.
Critical Coupling Between Optical Fibers and WGM Resonators
Matsko, Andrey; Maleki, Lute; Itchenko, Vladimir; Savchenkov, Anatoliy
2009-01-01
Two recipes for ensuring critical coupling between a single-mode optical fiber and a whispering-gallery-mode (WGM) optical resonator have been devised. The recipes provide for phase matching and aperture matching, both of which are necessary for efficient coupling. There is also a provision for suppressing intermodal coupling, which is detrimental because it drains energy from desired modes into undesired ones. According to one recipe, the tip of the single-mode optical fiber is either tapered in diameter or tapered in effective diameter by virtue of being cleaved at an oblique angle. The effective index of refraction and the phase velocity at a given position along the taper depend on the diameter (or effective diameter) and the index of refraction of the bulk fiber material. As the diameter (or effective diameter) decreases with decreasing distance from the tip, the effective index of refraction also decreases. Critical coupling and phase matching can be achieved by placing the optical fiber and the resonator in contact at the proper point along the taper. This recipe is subject to the limitation that the attainable effective index of refraction lies between the indices of refraction of the bulk fiber material and the atmosphere or vacuum to which the resonator and fiber are exposed. The other recipe involves a refinement of the previously developed technique of prism coupling, in which the light beam from the optical fiber is collimated and focused onto one surface of a prism that has an index of refraction greater than that of the resonator. Another surface of the prism is placed in contact with the resonator. The various components are arranged so that the collimated beam is focused at the prism/resonator contact spot. The recipe includes the following additional provisions:
Balanced mechanical resonator for powder handling device
Sarrazin, Philippe C. (Inventor); Brunner, Will M. (Inventor)
2012-01-01
A system incorporating a balanced mechanical resonator and a method for vibration of a sample composed of granular material to generate motion of a powder sample inside the sample holder for obtaining improved analysis statistics, without imparting vibration to the sample holder support.
Mechanical Resonances of Helically Coiled Carbon Nanowires
Saini, D.; Behlow, H.; Podila, R.; Dickel, D.; Pillai, B.; Skove, M. J.; Serkiz, S. M.; Rao, A. M.
2014-07-01
Despite their wide spread applications, the mechanical behavior of helically coiled structures has evaded an accurate understanding at any length scale (nano to macro) mainly due to their geometrical complexity. The advent of helically coiled micro/nanoscale structures in nano-robotics, nano-inductors, and impact protection coatings has necessitated the development of new methodologies for determining their shear and tensile properties. Accordingly, we developed a synergistic protocol which (i) integrates analytical, numerical (i.e., finite element using COMSOL®) and experimental (harmonic detection of resonance; HDR) methods to obtain an empirically validated closed form expression for the shear modulus and resonance frequency of a singly clamped helically coiled carbon nanowire (HCNW), and (ii) circumvents the need for solving 12th order differential equations. From the experimental standpoint, a visual detection of resonances (using in situ scanning electron microscopy) combined with HDR revealed intriguing non-planar resonance modes at much lower driving forces relative to those needed for linear carbon nanotube cantilevers. Interestingly, despite the presence of mechanical and geometrical nonlinearities in the HCNW resonance behavior the ratio of the first two transverse modes f2/f1 was found to be similar to the ratio predicted by the Euler-Bernoulli theorem for linear cantilevers.
Enhanced entanglement of two different mechanical resonators via coherent feedback
Li, Jie; Zippilli, Stefano; Vitali, David; Zhang, Tiancai
2016-01-01
It is shown [New J. Phys. 17, 103037 (2015)] that extremely large and robust entanglement between two different mechanical resonators could be achieved, either dynamically or in the steady state, in an optomechanical system in which a single cavity mode driven by a suitably chosen two-tone field is coupled to two mechanical modes. The main limitation of the scheme is that the cavity decay rate must be much smaller than the two mechanical frequencies and their difference, allowing taking the rotating wave approximation where counter-rotating, non-resonant terms associated with the bichromatic driving are negligible. Here we show that, by simply adding a coherent feedback loop, the large entanglement can be remarkably enhanced and the effective cavity decay rate can be significantly reduced. Therefore, it improves the results of Ref. [New J. Phys. 17, 103037 (2015)] and meantime greatly extends the validity of the scheme.
Wu, Yanan; Gong, Yubing; Xu, Bo
2013-12-01
Recently, multiple coherence resonance induced by time delay has been observed in neuronal networks with constant coupling strength. In this paper, by employing Newman-Watts Hodgkin-Huxley neuron networks with time-periodic coupling strength, we study how the temporal coherence of spiking behavior and coherence resonance by time delay change when the frequency of periodic coupling strength is varied. It is found that delay induced coherence resonance is dependent on periodic coupling strength and increases when the frequency of periodic coupling strength increases. Periodic coupling strength can also induce multiple coherence resonance, and the coherence resonance occurs when the frequency of periodic coupling strength is approximately multiple of the spiking frequency. These results show that for periodic coupling strength time delay can more frequently optimize the temporal coherence of spiking activity, and periodic coupling strength can repetitively optimize the temporal coherence of spiking activity as well. Frequency locking may be the mechanism for multiple coherence resonance induced by periodic coupling strength. These findings imply that periodic coupling strength is more efficient for enhancing the temporal coherence of spiking activity of neuronal networks, and thus it could play a more important role in improving the time precision of information processing and transmission in neural networks.
Li, Yangcheng
2015-01-01
In this dissertation novel resonant propulsion of dielectric microspheres is studied with the goal of sorting spheres with identical resonances, which are critical for developing microspherical photonics. First, evanescent field couplers were developed by fixing tapered microfibers in mechanically robust platforms. The tapers were obtained by chemical etching techniques. Using these platforms, WGMs modal numbers, coupling regimes and quality factors were determined for various spheres and compared with theory. Second, the spectroscopic properties of photonic molecules formed by spheres with better than 0.05% uniformity of WGM resonances were studied. It was shown that various spatial configurations of coupled-cavities present relatively stable mode splitting patterns in the fiber transmission spectra which can be used as spectral signatures to distinguish such photonic molecules. The third part is the study of giant resonant propulsion forces exerted on microspheres. This effect was observed in suspensions of...
Double resonance in the system of coupled Josephson junctions
Shukrinov, Yu. M.; Rahmonov, I. R.; Kulikov, K. V.
2013-01-01
The effect of LC shunting on the phase dynamics of coupled Josephson junctions has been examined. It has been shown that additional ( rc) branches appear in the current-voltage characteristics of the junctions when the Josephson frequency ωJ is equal to the natural frequency of the formed resonance circuit ωrc. The effect of the parameters of the system on its characteristics has been studied. Double resonance has been revealed in the system at ωJ = ωrc = 2ωLPW, where ωLPW is the frequency of a longitudinal plasma wave appearing under the parametric-resonance conditions. In this case, electric charge appears in superconducting layers in the interval of the bias current corresponding to the rc branch. The charge magnitude is determined by the accuracy with which the double resonance condition is satisfied. The possibility of the experimental implementation of the effects under study has been estimated.
Plasmon coupling in vertical split-ring resonator metamolecules
Wu, Pin Chieh; Hsu, Wei-Lun; Chen, Wei Ting; Huang, Yao-Wei; Liao, Chun Yen; Liu, Ai Qun; Zheludev, Nikolay I.; Sun, Greg; Tsai, Din Ping
2015-01-01
The past decade has seen a number of interesting designs proposed and implemented to generate artificial magnetism at optical frequencies using plasmonic metamaterials, but owing to the planar configurations of typically fabricated metamolecules that make up the metamaterials, the magnetic response is mainly driven by the electric field of the incident electromagnetic wave. We recently fabricated vertical split-ring resonators (VSRRs) which behave as magnetic metamolecules sensitive to both incident electric and magnetic fields with stronger induced magnetic dipole moment upon excitation in comparison to planar SRRs. The fabrication technique enabled us to study the plasmon coupling between VSRRs that stand up side by side where the coupling strength can be precisely controlled by varying the gap in between. The resulting wide tuning range of these resonance modes offers the possibility of developing frequency selective functional devices such as sensors and filters based on plasmon coupling with high sensitivity. PMID:26043931
Hund's coupling case sequences in resonant multiphoton transitions
Maïnos, C.; Castex, M. C.; Nkwawo, H.
1990-10-01
Different Hund's coupling case sequences are considered for the n1+n2 near resonant multiphoton rovibronic process in electric dipole allowed transitions of any spin multiplicity. The transitional path interferences strength tensor is introduced. This tensor involves a polarization and rotational dependence as well as a transitional path dependence which couples the electronic vibrational motion with the rotational structure. The intensity of a rotational line may decompose in terms of the matrix element of this tensor and a pure electronic vibrational tensor. The specificity of the coupling case sequence is found condensed in the rotational line factors which are explicitly determined for all the coupling case sequences obtained from the case (a) and case (b) coupling.
Detecting weak coupling in mesoscopic systems with a nonequilibrium Fano resonance
Xiao, S.; Yoon, Y.; Lee, Y.-H.; Bird, J. P.; Ochiai, Y.; Aoki, N.; Reno, J. L.; Fransson, J.
2016-04-01
A critical aspect of quantum mechanics is the nonlocal nature of the wave function, a characteristic that may yield unexpected coupling of nominally isolated systems. The capacity to detect this coupling can be vital in many situations, especially those in which its strength is weak. In this work, we address this problem in the context of mesoscopic physics, by implementing an electron-wave realization of a Fano interferometer using pairs of coupled quantum point contacts (QPCs). Within this scheme, the discrete level required for a Fano resonance is provided by pinching off one of the QPCs, thereby inducing the formation of a quasibound state at the center of its self-consistent potential barrier. Using this system, we demonstrate a form of nonequilibrium Fano resonance (NEFR), in which nonlinear electrical biasing of the interferometer gives rise to pronounced distortions of its Fano resonance. Our experimental results are captured well by a quantitative theoretical model, which considers a system in which a standard two-path Fano interferometer is coupled to an additional, intruder, continuum. According to this theory, the observed distortions in the Fano resonance arise only in the presence of coupling to the intruder, indicating that the NEFR provides a sensitive means to infer the presence of weak coupling between mesoscopic systems.
Quantum kinetics of ultracold fermions coupled to an optical resonator
Piazza, Francesco; Strack, Philipp
2014-10-01
We study the far-from-equilibrium statistical mechanics of periodically driven fermionic atoms in a lossy optical resonator. We show that the interplay of the Fermi surface with cavity losses leads to subnatural cavity linewidth narrowing, squeezed light, and nonthermal quantum statistics of the atoms. Adapting the Keldysh approach, we set up and solve a quantum kinetic Boltzmann equation in a systematic 1/N expansion with N the number of atoms. In the strict thermodynamic limit N ,V→∞,N/V=const. we find that the atoms (fermions or bosons) remain immune against cavity-induced heating or cooling. At next-to-leading order in 1/N, we find a "one-way thermalization" of the atoms determined by cavity decay. In absence of an equilibrium fluctuation-dissipation relation, the long-time limit Δt →∞ does not commute with the thermodynamic limit N →∞, such that for the physically relevant case of large but finite N, the dynamics ultimately becomes strongly coupled, especially close to the superradiance phase transition.
Fano-like resonances in strongly coupled binary Coulomb systems
Silvestri, Luciano; Donko, Zoltan; Hartmann, Peter; Kaehlert, Hanno
2014-01-01
Molecular dynamics (MD) simulations of a strongly coupled binary ionic mixture have shown the presence of a sharp minimum in the dynamical density fluctuation spectrum. This phenomenon is reminiscent of the well known Fano anti-resonance, occurring in various physical processes. We give a theoretical analysis using the Quasi Localized Charge Approximation, pointing out that the observed phenomenon in the equilibrium spectrum is the consequence, induced by the Fluctuation-Dissipation Theorem, of the Fano anti-resonance, whose existence in the system is verified by further MD simulation.
Coupling Between Corotation And Lindblad Mean Motion Resonances
El Moutamid, Maryame; Sicardy, B.; Renner, S.
2012-10-01
We consider the classical Elliptic Restricted Three-Body Problem with two bodies (particle and satellite) orbiting a central planet. If we take into account the oblateness of the central body through the classical additional terms up to J_6, the secular terms causing the orbit precessions appear in the disturbing potential leading to the presence of two critical resonant arguments : Φ = (m+1)λ‧ + mλ + ω and Φ‧ = (m+1)λ‧ + mλ + ω‧ where m is an integer, λ and ω the mean longitude and the longitude of the periapsis of the particle, and the primed quantities apply to the satellite. The arguments Φ‧ and Φ respectively describe the Corotation Eccentric Resonance (CER) and the Lindblad Eccentric Resonance (LER). We developed a new model (the CoraLin model) which encapsulate in a simple adimensional form the coupling between the two resonances. We examine the asymptotic configurations where these resonances are well separated or completely superimposed. Poincaré surfaces of section reveal that in intermediate cases, the strong coupling between the resonances may lead to chaotic behavior. We apply this model to several recently discovered small Saturnian satellites dynamically linked to Mimas through first mean motion resonances : Anthe, Methone, and Aegaeon, all associated with arc material. All satellites are trapped in CER with Mimas and perturbed by the associated LER. We estimate the probability of capturing a satellite into a of CER with Mimas, as the orbit of the latter evolves through tidal effects, and discuss possible scenarios for the the dynamical origin of those moons.
Zhang, Zhengren, E-mail: zhrenzhang@126.com [School of Science, Chongqing Jiaotong University, Chongqing 400074 (China); Zhang, Liwei [School of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Yin, Pengfei; Han, Xiangyu [School of Science, Chongqing Jiaotong University, Chongqing 400074 (China)
2014-08-01
We investigate theoretically the generation process of coupled resonator-induced transparency (CRIT) in surface plasmon polariton gap waveguide system containing two side-coupled cavities, which locate at a symmetric position. The CRIT is original from the destructive interference of the two detuned cavities. In contrast with the existing electromagnetically induced transparency (EIT) schemes, the occurrence of the CRIT is caused by the two radiative cavities in waveguide, instead of interference between a dark cavity and radiative cavity. This behavior mimics the quantum interference between two direct excitation pathways in a three-level V-type atom. The transmission lineshape can be tuned between an EIT-like resonant peak and a Lorentzian-like resonant dip by tailoring the detuning of the two cavities. Moreover, we also find that the transparency peak moves to high frequency with a line shift and its Q factor decreases with the increase of coupling distance between the cavities and waveguide.
Frequency locking in hair cells: Distinguishing between distinct resonant mechanisms
Edri, Yuval; Yochelis, Arik
2016-01-01
The auditory system displays remarkable mechanical sensitivity and frequency discrimination. These attributes have been shown to rely on an amplification process, which requires biochemical feedback loops. In some systems, the active process was shown to lead to spontaneous oscillations of hair cell bundles. In the last decade, models that display proximity to an oscillatory onset (a.k.a. Hopf bifurcation) have gained increasing support due to many advantages in explaining the hearing phenomenology. Particularly, they exhibit resonant responses to distinct frequencies of incoming sound waves. Unlike previous studies, two types of driving forces are being examined: additive, in which the external forcing term does not couple directly on the systems observable (passive coupling), and parametric, in which the forcing term directly affects the observable and thus intrinsically modifies the systems properties (active coupling). By applying universal principles near the Hopf bifurcation onset, we find several funda...
Collective behavior of quantum resonators coupled to a metamaterial
Felbacq, Didier; Rousseau, Emmanuel
2016-09-01
We study a device that consist of quantum resonators coupled to a mesoscopic photonic structure, such as a metasurface or a 2D metamaterial. For metasurfaces, we use surface Bloch modes in order to reach various coupling regimes between the metasurface and a quantum emitter, modelized semi-classically by an oscillator. Using multiple scattering theory and complex plane techniques, we show that the coupling can be characterized by means of a pole-and-zero structure. The regime of strong coupling is shown to be reached when the pole-and- zero pair is broken. For 2D metamaterial, we show the possibility of controlling optically the opening or closing of a gap.
Comparison of acoustically coupled and mechanically coupled speech.
Cook, R O; Hamm, C W; Thomas, W G; Royster, L H
1981-01-01
Phonetically balanced work lists were mechanically coupled onto the ossicular chain of anesthetized guinea pigs by piezoelectric-type drivers and the resulting cochlear microphonic (CM) recorded on magnetic tape. Similar recordings of the CM resulting from free field tympanic membrane stimulation by hi-fi speakers were also obtained. The recordings were compared by conventional discrimination testing. In discrimination testing of all the raw recordings, listeners achieved essentially perfect scores. Addition of masking noise sufficient to reduce mean discrimination scores to 65-70% revealed no significant discrimination differences. When piezoelectrically initiated, CM-derived lists were compared with similar lists passed through hearing aids in an anechoic chamber, the preference of a panel of listeners for the quality of mechanically coupled speech was significantly higher. Mechanical-acoustical displacement equivalency at normal physiological levels and freedom from mechanical-electrical artifact were demonstrated by measurement of ossicular chain displacement by a fiber optic lever displacement transducer.
$\\rho$-Nucleon Tensor Coupling and Charge-Exchange Resonances
De Conti, C; Krmpotic, F
2000-01-01
The Gamow-Teller resonances are discussed in the context of a self-consistentRPA, based on the relativistic mean field theory. We inquire on the possibilityof substituting the phenomenological Landau-Migdal force by a microscopicnucleon-nucleon interaction, generated from the rho-nucleon tensor coupling.The effect of this coupling turns out to be very small when the short rangecorrelations are not taken into account, but too large when these correlationsare simulated by the simple extraction of the contact terms from the resultingnucleon-nucleon interaction.
Multistable internal resonance in electroelastic crystals with nonlinearly coupled modes
Kirkendall, Christopher R.; Kwon, Jae W.
2016-03-01
Nonlinear modal interactions have recently become the focus of intense research in micro- and nanoscale resonators for their use to improve oscillator performance and probe the frontiers of fundamental physics. However, our understanding of modal coupling is largely restricted to clamped-clamped beams, and lacking in systems with both geometric and material nonlinearities. Here we report multistable energy transfer between internally resonant modes of an electroelastic crystal plate and use a mixed analytical-numerical approach to provide new insight into these complex interactions. Our results reveal a rich bifurcation structure marked by nested regions of multistability. Even the simple case of two coupled modes generates a host of topologically distinct dynamics over the parameter space, ranging from the usual Duffing bistability to complex multistable behaviour and quasiperiodic motion.
Coupled-resonator-induced-transparency concept for wavelength routing applications.
Mancinelli, M; Guider, R; Bettotti, P; Masi, M; Vanacharla, M R; Pavesi, L
2011-06-20
The presence of coupled resonators induced transparency (CRIT) effects in side-coupled integrated spaced sequence of resonators (SCISSOR) of different radii has been studied. By controlling the rings radii and their center to center distance, it is possible to form transmission channels within the SCISSOR stop-band. Two different methods to exploit the CRIT effect in add/drop filters are proposed. Their performances, e. g. linewidth, crosstalk and losses, are examined also for random variations in the structural parameters. Finally, few examples of high performances mux/demux structures and 2 × 2 routers based on these modified SCISSOR are presented. CRIT based SCISSOR optical devices are particularly promising for ultra-dense wavelength division multiplexing applications.
Coupling a thermal atomic vapor to an integrated ring resonator
Ritter, Ralf; Pernice, Wolfram; Kübler, Harald; Pfau, Tilman; Löw, Robert
2016-01-01
Strongly interacting atom-cavity systems within a network with many nodes constitute a possible realization for a quantum internet which allows for quantum communication and computation on the same platform. To implement such large-scale quantum networks, nanophotonic resonators are promising candidates because they can be scalably fabricated and interconnected with waveguides and optical fibers. By integrating arrays of ring resonators into a vapor cell we show that thermal rubidium atoms above room temperature can be coupled to photonic cavities as building blocks for chip-scale hybrid circuits. Although strong coupling is not yet achieved in this first realization, our approach provides a key step towards miniaturization and scalability of atom-cavity systems.
Coupling ultracold atoms to mechanical oscillators
Hunger, David; Korppi, Maria; Jöckel, Andreas; Hänsch, Theodor W; Treutlein, Philipp
2011-01-01
In this article we discuss and compare different ways to engineer an interface between ultracold atoms and micro- and nanomechanical oscillators. We start by analyzing a direct mechanical coupling of a single atom or ion to a mechanical oscillator and show that the very different masses of the two systems place a limit on the achievable coupling constant in this scheme. We then discuss several promising strategies for enhancing the coupling: collective enhancement by using a large number of atoms in an optical lattice in free space, coupling schemes based on high-finesse optical cavities, and coupling to atomic internal states. Throughout the manuscript we discuss both theoretical proposals and first experimental implementations.
Quantum transport in coupled resonators enclosed synthetic magnetic flux
Jin, L.
2016-07-01
Quantum transport properties are instrumental to understanding quantum coherent transport processes. Potential applications of quantum transport are widespread, in areas ranging from quantum information science to quantum engineering, and not restricted to quantum state transfer, control and manipulation. Here, we study light transport in a ring array of coupled resonators enclosed synthetic magnetic flux. The ring configuration, with an arbitrary number of resonators embedded, forms a two-arm Aharonov-Bohm interferometer. The influence of magnetic flux on light transport is investigated. Tuning the magnetic flux can lead to resonant transmission, while half-integer magnetic flux quantum leads to completely destructive interference and transmission zeros in an interferometer with two equal arms.
Monitoring microbial metabolites using an inductively coupled resonance circuit
Karnaushenko, Daniil; Baraban, Larysa; Ye, Dan; Uguz, Ilke; Mendes, Rafael G.; Rümmeli, Mark H.; de Visser, J. Arjan G. M.; Schmidt, Oliver G.; Cuniberti, Gianaurelio; Makarov, Denys
2015-08-01
We present a new approach to monitor microbial population dynamics in emulsion droplets via changes in metabolite composition, using an inductively coupled LC resonance circuit. The signal measured by such resonance detector provides information on the magnetic field interaction with the bacterial culture, which is complementary to the information accessible by other detection means, based on electric field interaction, i.e. capacitive or resistive, as well as optical techniques. Several charge-related factors, including pH and ammonia concentrations, were identified as possible contributors to the characteristic of resonance detector profile. The setup enables probing the ionic byproducts of microbial metabolic activity at later stages of cell growth, where conventional optical detection methods have no discriminating power.
Wireless power transfer via strongly coupled magnetic resonances.
Kurs, André; Karalis, Aristeidis; Moffatt, Robert; Joannopoulos, J D; Fisher, Peter; Soljacic, Marin
2007-07-06
Using self-resonant coils in a strongly coupled regime, we experimentally demonstrated efficient nonradiative power transfer over distances up to 8 times the radius of the coils. We were able to transfer 60 watts with approximately 40% efficiency over distances in excess of 2 meters. We present a quantitative model describing the power transfer, which matches the experimental results to within 5%. We discuss the practical applicability of this system and suggest directions for further study.
WIRELESS POWER TRANSMISSION USING INDUCTIVE RESONANCE COUPLING IN MOBILE CHARGERING
Valarmathi Krishnan*, N. Suyambu, Vijayaragavan. M, Rajalakshmi. S
2016-01-01
The objective of this technical report is to provide electrical energy to remote objects without wires. Wireless energy transfer also known as wireless energy transmission is the process that takes place in any system where electromagnetic energy is transmitted from a power source to an electrical load, without interconnecting wires. The principle of wireless electricity works on the principle of using coupled resonant objects for the transfer of electricity to objects without the use of an...
Quantum transport in coupled resonators enclosed synthetic magnetic flux
Jin, L., E-mail: jinliang@nankai.edu.cn
2016-07-15
Quantum transport properties are instrumental to understanding quantum coherent transport processes. Potential applications of quantum transport are widespread, in areas ranging from quantum information science to quantum engineering, and not restricted to quantum state transfer, control and manipulation. Here, we study light transport in a ring array of coupled resonators enclosed synthetic magnetic flux. The ring configuration, with an arbitrary number of resonators embedded, forms a two-arm Aharonov–Bohm interferometer. The influence of magnetic flux on light transport is investigated. Tuning the magnetic flux can lead to resonant transmission, while half-integer magnetic flux quantum leads to completely destructive interference and transmission zeros in an interferometer with two equal arms. -- Highlights: •The light transport is investigated through ring array of coupled resonators enclosed synthetic magnetic field. •Aharonov–Bohm ring interferometer of arbitrary configuration is investigated. •The half-integer magnetic flux quantum leads to destructive interference and transmission zeros for two-arm at equal length. •Complete transmission is available via tuning synthetic magnetic flux.
Mechanism of the metallic metamaterials coupled to the gain material.
Huang, Zhixiang; Droulias, Sotiris; Koschny, Thomas; Soukoulis, Costas M
2014-11-17
We present evidence of strong coupling between the gain material and the metallic metamaterials. It is of vital importance to understand the mechanism of the coupling of metamaterials with the gain medium. Using a four-level gain system, the numerical pump-probe experiments are performed in several configurations (split-ring resonators (SRRs), inverse SRRs and fishnets) of metamaterials, demonstrating reduction of the resonator damping in all cases and hence the possibility for loss compensation. We find that the differential transmittance ΔT/T can be negative in different SRR configurations, such as SRRs on the top of the gain substrate, gain in the SRR gap and gain covering the SRR structure, while in the fishnet metamaterial with gain ΔT/T is positive.
Reheating mechanism of Curvaton with Nonminimal Derivative Coupling to Gravity
Qiu, Taotao
2016-01-01
In this paper, we continue our study on the curvaton model with nonminimal derivative coupling (NDC) to Einstein gravity proposed in our previous work, focusing on the reheating mechanism. We found that according to whether the curvaton has dominated the background after the end of inflation, it will have two different behaviors of evolution, which should be the general property of curvaton with nonminimal couplings. This will cause diffferent rates of particle creation, which goes on via the parametric resonance process. The reheating temperature is estimated for both cases in which reheating completes before and after curvaton domination, and the constraints are quite loose compared to that of overproduction of gravitino. Finally we investigated the evolution of curvature perturbation during reheating. We have shown both analytically and numerically that the curvature perturbation will not blow up during the resonance process.
The effect of coupling line loss in microstrip to dielectric resonator coupling
Hearn, C. P.; Bradshaw, E. S.; Trew, R. J.
1990-01-01
The interaction between a dielectric resonator and a microstrip transmission line is fundamentally a field phenomenon. However, the model of Figure 1b widely is used to represent the arrangement in Figure 1a, and predicts the behavior encountered in practice. The microstrip line of length l = n(lambda)/4 between the input and coupling planes and the lambda/4 open-circuit stub usually is assumed to be lossless. This paper considers the effect of coupling line loss on the unloaded-Q and coupling coefficient beta of the combination. It shows that transmission line loss can cause the decrease in unloaded-Q that has been observed to occur with tight coupling, and limits the coupling coefficient to a much lower value than would be obtained with a lossless coupling line.
On the mechanism of electrochemical modulation of plasmonic resonances
Shao, L.-H.; Ruther, M.; Linden, S.; Wegener, M.; Weissmüller, J.
2012-09-01
Recent electrochemical experiments on gold-based photonic metamaterials have shown a sizable reversible tuning and modulation of plasmonic resonances. Here, we study the mechanism of the electrochemical modulation by measuring the change of the resonance transmittance and resonance frequency during underpotential deposition of Pb, Cu, and electrosorption of OH. The electric resistance change of the resonators is identified as decisive for the resonance transmittance change, while the space-charge layer at the metal surface shifts the resonance frequency.
Transmission of asymmetric coupling double-ring resonator
Zhao, C. Y.; Tan, W. H.
2015-02-01
Based on the asymmetry between waveguide and double ring, the transmission and phase characteristics of coupled double-ring resonators are analyzed systemically. It is shown that the initial detuning determines the shape of transmission spectrum. The transmission spectrum of all-optical analog to electromagnetic inducted transparency (EIT) is controlled by tuning the asymmetric coupled parameter and loss. With the increasing of asymmetric coupled parameter, the transmission spectrum changes from EIT-like profile to Lorenz profile. The EIT-like transmission spectrum results from the interference between two Lorenz profiles. With the increasing of the loss, the transmission spectrum full frequency width at half-maximum broadens and its peak declines. The detuning and loss also make significant influences on the phase profile.
Mode Coupling and Nonlinear Resonances of MEMS Arch Resonators for Bandpass Filters
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.
Fast readout of carbon nanotube mechanical resonators
Meerwaldt, Harold; Singh, Vibhor; Schneider, Ben; Schouten, Raymond; van der Zant, Herre; Steele, Gary
2013-03-01
We perform fast readout measurements of carbon nanotube mechanical resonators. Using an electronic mixing scheme, we can detect the amplitude of the mechanical motion with an intermediate frequency (IF) of 46 MHz and a timeconstant of 1 us, up to 5 orders of magnitude faster than before. Previous measurements suffered from a low bandwidth due to the combination of the high resistance of the carbon nanotube and a large stray capacitance. We have increased the bandwidth significantly by using a high-impedance, close-proximity HEMT amplifier. The increased bandwidth should allow us to observe the nanotube's thermal motion and its transient response, approaching the regime of real-time detection of the carbon nanotube's mechanical motion.
Caricato, Marco; Curutchet, Carles; Mennucci, Benedetta; Scalmani, Giovanni
2015-11-10
Quantum mechanical (QM) calculations of electronic couplings provide great insights for the study of resonance energy transfer (RET). However, most of these calculations rely on approximate QM methods due to the computational limitations imposed by the size of typical donor-acceptor systems. In this work, we present a novel implementation that allows computing electronic couplings at the coupled cluster singles and doubles (CCSD) level of theory. Solvent effects are also taken into account through the polarizable continuum model (PCM). As a test case, we use a dimer of indole, a common model system for tryptophan, which is routinely used as an intrinsic fluorophore in Förster resonance energy transfer studies. We consider two bright π → π* states, one of which has charge transfer character. Lastly, the results are compared with those obtained by applying TD-DFT in combination with one of the most popular density functionals, B3LYP.
Electrothermal Frequency Modulated Resonator for Mechanical Memory
Hafiz, Md Abdullah Al
2016-08-18
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 is deliberately fabricated as an in-plane shallow arch to achieve geometric quadratic nonlinearity. We exploit this inherent nonlinearity of the arch and drive it at resonance with minimal actuation voltage into the nonlinear regime, thereby creating softening behavior, hysteresis, and coexistence of states. The hysteretic frequency band is controlled by the electrothermal actuation voltage. Binary values are assigned to the two allowed dynamical states on the hysteretic response curve of the arch resonator with respect to the electrothermal actuation voltage. Set-and-reset operations of the memory states are performed by applying controlled dc pulses provided through the electrothermal actuation scheme, while the read-out operation is performed simultaneously by measuring the motional current through a capacitive detection technique. This novel memory device has the advantages of operating at low voltages and under room temperature. [2016-0043
Perfect and broadband acoustic absorption by critically coupled sub-wavelength resonators.
Romero-García, V; Theocharis, G; Richoux, O; Merkel, A; Tournat, V; Pagneux, V
2016-01-19
Perfect absorption is an interdisciplinary topic with a large number of applications, the challenge of which consists of broadening its inherently narrow frequency-band performance. We experimentally and analytically report perfect and broadband absorption for audible sound, by the mechanism of critical coupling, with a sub-wavelength multi-resonant scatterer (SMRS) made of a plate-resonator/closed waveguide structure. In order to introduce the role of the key parameters, we first present the case of a single resonant scatterer (SRS) made of a Helmholtz resonator/closed waveguide structure. In both cases the controlled balance between the energy leakage of the several resonances and the inherent losses of the system leads to perfect absorption peaks. In the case of the SMRS we show that systems with large inherent losses can be critically coupled using resonances with large leakage. In particular, we show that in the SMRS system, with a thickness of λ/12 and diameter of λ/7, several perfect absorption peaks overlap to produce absorption bigger than 93% for frequencies that extend over a factor of 2 in audible frequencies. The reported concepts and methodology provide guidelines for the design of broadband perfect absorbers which could contribute to solve the major issue of noise reduction.
Direct and indirect coupling mechanisms in a chiral plasmonic system
Wang, Yongkai; Wen, Xiaojing; Qu, Yu; Fu, Tong; Zhang, Zhongyue
2016-10-01
Artificial chiral plasmonic nanostructures (ACPNs) are widely studied and used in biological monitoring, analytical chemistry, and negative-refractive-index media. The mechanism of direct coupling between two twist metal nanorods has been obtained in usual ACPNs. In this work, we proposed a nanosystem of twist nanorods separated by a metal film (TNMF). By analyzing the charge distributions, a new indirect coupling mechanism is found. According to the equivalent LC resonant circuits, gold nanorods on the two sides of the gold film can be regarded as a receiver and an emitter. These components enhanced transmittance and provided direct and indirect coupling mechanisms for the circular dichroism (CD). The direct coupling mode cannot be explained by impedance matching and can be tuned monotonously by monotonously varying geometric dimensions. However, the CD signal of indirect coupling can be explained by impedance matching and can be tuned to its maximum by varying geometric dimensions when the impedances of both sides of the gold film match. These results can help design novel chiral optical structures and promote combined applications between photons and electrons when a gold film is powered on.
Resonance coupling in plasmonic nanomatryoshka homo- and heterodimers
Ahmadivand, Arash; Sinha, Raju; Pala, Nezih
2016-06-01
Here, we examine the electromagnetic (EM) energy coupling and hybridization of plasmon resonances between closely spaced concentric nanoshells known as "nanomatryoshka" (NM) units in symmetric and antisymmetric compositions using the Finite Difference Time Domain (FDTD) analysis. Utilizing plasmon hybridization model, we calculated the energy level diagrams and verified that, in the symmetric dimer (in-phase mode in a homodimer), plasmonic bonding modes are dominant and tunable within the considered bandwidth. In contrast, in the antisymmetric dimer (out-of-phase mode in a heterodimer), due to the lack of the geometrical symmetry, new antibonding modes appear in the extinction profile, and this condition gives rise to repeal of dipolar field coupling. We also studied the extinction spectra and positions of the antibonding and bonding modes excited due to the energy coupling between silver and gold NM units in a heterodimer structure. Our analysis suggest abnormal shifts in the higher energy modes. We propose a method to analyze the behavior of multilayer concentric nanoshell particles in an antisymmetric orientation employing full dielectric function calculations and the Drude model based on interband transitions in metallic components. This study provides a method to predict the behavior of the higher energy plasmon resonant modes in entirely antisymmetric structures such as compositional heterodimers.
Resonance coupling in plasmonic nanomatryoshka homo- and heterodimers
Arash Ahmadivand
2016-06-01
Full Text Available Here, we examine the electromagnetic (EM energy coupling and hybridization of plasmon resonances between closely spaced concentric nanoshells known as “nanomatryoshka” (NM units in symmetric and antisymmetric compositions using the Finite Difference Time Domain (FDTD analysis. Utilizing plasmon hybridization model, we calculated the energy level diagrams and verified that, in the symmetric dimer (in-phase mode in a homodimer, plasmonic bonding modes are dominant and tunable within the considered bandwidth. In contrast, in the antisymmetric dimer (out-of-phase mode in a heterodimer, due to the lack of the geometrical symmetry, new antibonding modes appear in the extinction profile, and this condition gives rise to repeal of dipolar field coupling. We also studied the extinction spectra and positions of the antibonding and bonding modes excited due to the energy coupling between silver and gold NM units in a heterodimer structure. Our analysis suggest abnormal shifts in the higher energy modes. We propose a method to analyze the behavior of multilayer concentric nanoshell particles in an antisymmetric orientation employing full dielectric function calculations and the Drude model based on interband transitions in metallic components. This study provides a method to predict the behavior of the higher energy plasmon resonant modes in entirely antisymmetric structures such as compositional heterodimers.
Moving boundary and photoelastic coupling in GaAs optomechanical resonators
Balram, Krishna C; Lim, Ju Young; Song, Jin Dong; Srinivasan, K
2014-01-01
Chip-based cavity optomechanical systems are being considered for applications in sensing, metrology, and quantum information science. Critical to their development is an understanding of how the optical and mechanical modes interact, quantified by the coupling rate $g_{0}$. Here, we develop GaAs optomechanical resonators and investigate the moving dielectric boundary and photoelastic contributions to $g_{0}$. First, we consider coupling between the fundamental radial breathing mechanical mode and a 1550 nm band optical whispering gallery mode in microdisks. For decreasing disk radius from $R=5$ $\\mu$m to $R=1$ $\\mu$m, simulations and measurements show that $g_{0}$ changes from being dominated by the moving boundary contribution to having an equal photoelastic contribution. Next, we design and demonstrate nanobeam optomechanical crystals in which a $2.5$ GHz mechanical breathing mode couples to a 1550 nm optical mode predominantly through the photoelastic effect. We show a significant (30 $\\%$) dependence of ...
Halo Coupling and Cleaning by a Space Charge Resonance in High Intensity Beams
Hofmann, Ingo
2013-01-01
We show that the difference resonance driven by the space charge pseudo-octupole of high-intensity beams not only couples the beam core emittances; it can also lead to emittance exchange in the beam halo, which is of relevance for beam loss in high intensity accelerators. With reference to linear accelerators the "main resonance" kz/kxy =1 (corresponding to the Montague resonance 2Qx-2Qy=0 in circular accelerators) may lead to such a coupling and transfer of halo between planes. Coupling of transverse halo into the longitudinal plane - or vice versa - can occur even if the core (rms) emittances are exactly or nearly equal. This halo argument justifies additional caution in linac design including consideration of avoiding an equipartitioned design. At the same time, however, this mechanism may also qualify as active dynamical halo cleaning scheme by coupling a halo from the longitudinal plane into the transverse plane, where local scraping is accessible. We present semi-analytical emittance coupling rates and ...
Selective effects of noise by stochastic multi-resonance in coupled cells system
2008-01-01
By investigating a stochastic model for intracellular calcium oscillations proposed by Hfer,we have analyzed the transmission behavior of calcium signaling in a one-dimensional two-way coupled hepatocytes system.It is shown that when the first cell is subjected to the external noise,the output signal-to-noise ratio(SNR) in the cell exhibits two maxima as a function of external noise intensity,indicating the occurrence of stochastic bi-resonance(SBR).It is more important that when cells are coupled together,the resonant behavior in the 1st cell propagates along the chain with different features through the coupling effect.The cells whose locations are comparatively close to or far from the 1st cell can show SBR,while the cells located in the middle position can display stochastic multi-resonance(SMR).Fur-thermore,the number of cells that can show SMR increases with coupling strength enhancing.These results indicate that the cells system may make an effective choice in response to external signaling induced by noise,through the mechanism of SMR by adjusting coupling strength.
Beam engineering for selective and enhanced coupling to multipolar resonances
Das, Tanya; Schuller, Jon A
2015-01-01
Multipolar electromagnetic phenomena in sub-wavelength resonators are at the heart of metamaterial science and technology. In this letter, we demonstrate selective and enhanced coupling to specific multipole resonances via beam engineering. We first derive an analytical method for determining the scattering and absorption of spherical nanoparticles (NPs) that depends only on the local electromagnetic field quantities within an inhomogeneous beam. Using this analytical technique, we demonstrate the ability to drastically manipulate the scattering properties of a spherical NP by varying illumination properties and demonstrate the excitation of a longitudinal quadrupole mode that cannot be accessed with conventional illumination. This work enhances the understanding of fundamental light-matter interactions in metamaterials, and lays the foundation for researchers to identify, quantify, and manipulate multipolar light-matter interactions through optical beam engineering.
Dynamical Coupled-Channel Model of Meson Production Reactions in the Nucleon Resonance Region
T.-S. H. Lee; A. Matsuyama; T. Sato
2006-11-15
A dynamical coupled-channel model is presented for investigating the nucleon resonances (N*) in the meson production reactions induced by pions and photons. Our objective is to extract the N* parameters and to investigate the meson production reaction mechanisms for mapping out the quark-gluon substructure of N* from the data. The model is based on an energy-independent Hamiltonian which is derived from a set of Lagrangians by using a unitary transformation method.
Analytical solutions of coupled-mode equations for microring resonators
ZHAO C Y
2016-06-01
We present a study on analytical solutions of coupled-mode equations for microring resonators with an emphasis on occurrence of all-optical EIT phenomenon, obtained by using a cofactor. As concrete examples, analytical solutions for a $3 \\times 3$ linearly distributed coupler and a circularly distributed coupler are obtained. The former corresponds to a non-degenerate eigenvalue problem and the latter corresponds to a degenerate eigenvalue problem. For comparison and without loss of generality, analytical solution for a $4 \\times 4$ linearly distributed coupler is also obtained. This paper may be of interest to optical physics and integrated photonics communities.
Wireless energy transfer through non-resonant magnetic coupling
Peng, Liang; Breinbjerg, Olav; Mortensen, Asger
2010-01-01
We demonstrate by theoretical analysis and experimental verification that mid-range wireless energy transfer systems may take advantage of de-tuned coupling devices, without jeopardizing the energy transfer efficiency. Allowing for a modest de-tuning of the source coil, energy transfer systems...... could be properly designed to minimize undesired energy dissipation in the source coil when the power receiver is out of the range. Our basic observation paves the way for more flexible design and fabrication of non-resonant mid-range wireless energy transfer systems, thus potentially impacting...... practical implementations of wireless energy transfer....
Efficient estimation of resonant coupling between quantum systems.
Stenberg, Markku P V; Sanders, Yuval R; Wilhelm, Frank K
2014-11-21
We present an efficient method for the characterization of two coupled discrete quantum systems, one of which can be controlled and measured. For two systems with transition frequencies ωq, ωr, and coupling strength g we show how to obtain estimates of g and ωr whose error decreases exponentially in the number of measurement shots rather than as a power law expected in simple approaches. Our algorithm can thereby identify g and ωr simultaneously with high precision in a few hundred measurement shots. This is achieved by adapting measurement settings upon data as it is collected. We also introduce a method to eliminate erroneous estimates with small overhead. Our algorithm is robust against the presence of relaxation and typical noise. Our results are applicable to many candidate technologies for quantum computation, in particular, for the characterization of spurious two-level systems in superconducting qubits or stripline resonators.
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.
Pattern Formation in Double-Layer Kerr Resonators with Coupled Modes
Bois, Antoine
2016-01-01
A double-layer Kerr resonator in which both coupled modes are excited and interact with each other via incoherent cross-phase modulation is investigated to reveal stable localized solutions beyond the usual formation mechanism involving a single mode. Periodic solutions from modulational instability are found to occur at a slight penalty on the nonlinear efficiency, but they stabilize the spatial dynamics, leading to dissipative solitons in previously unattainable regimes. Numerical simulations show paired breather solitons in addition to temporally stable solutions. The results demonstrate coupled modes can increase the stability of Kerr frequency comb generation.
Tipikin, D S; Earle, K A; Freed, J H
2010-01-01
The sensitivity of a high frequency electron spin resonance (ESR) spectrometer depends strongly on the structure used to couple the incident millimeter wave to the sample that generates the ESR signal. Subsequent coupling of the ESR signal to the detection arm of the spectrometer is also a crucial consideration for achieving high spectrometer sensitivity. In previous work, we found that a means for continuously varying the coupling was necessary for attaining high sensitivity reliably and reproducibly. We report here on a novel asymmetric mesh structure that achieves continuously variable coupling by rotating the mesh in its own plane about the millimeter wave transmission line optical axis. We quantify the performance of this device with nitroxide spin-label spectra in both a lossy aqueous solution and a low loss solid state system. These two systems have very different coupling requirements and are representative of the range of coupling achievable with this technique. Lossy systems in particular are a demanding test of the achievable sensitivity and allow us to assess the suitability of this approach for applying high frequency ESR to the study of biological systems at physiological conditions, for example. The variable coupling technique reported on here allows us to readily achieve a factor of ca. 7 improvement in signal to noise at 170 GHz and a factor of ca. 5 at 95 GHz over what has previously been reported for lossy samples.
Naqui, J.; Su, L., E-mail: lijuan.suri.su@gmail.com; Mata, J.; Martín, F., E-mail: Ferran.Martin@uab.es
2015-06-01
This paper is focused on the analysis of transmission lines loaded with pairs of magnetically coupled resonators. We have considered two different structures: (i) a microstrip line loaded with pairs of stepped impedance resonators (SIRs), and (ii) a coplanar waveguide (CPW) transmission line loaded with pairs of split ring resonators (SRRs). In both cases, the line exhibits a single resonance frequency (transmission zero) if the resonators are identical (symmetric structure with regard to the line axis), and this resonance is different to the one of the line loaded with a single resonator due to inter-resonator coupling. If the structures are asymmetric, inter-resonator coupling enhances the distance between the two split resonance frequencies that arise. In spite that the considered lines and loading resonators are very different and are described by different lumped element equivalent circuit models, the phenomenology associated to the effects of coupling is exactly the same, and the resonance frequencies are given by identical expressions. The reported lumped element circuit models of both structures are validated by comparing the circuit simulations with extracted parameters with both electromagnetic simulations and experimental data. These structures can be useful for the implementation of microwave sensors based on symmetry properties. - Highlights: • Magnetic-coupling between resonant elements affects transmission properties. • Inter-resonant coupling enhances the distance of two resonant frequencies. • The structures are useful for sensors and comparators, etc.
Electro-Mechanical Resonant Magnetic Field Sensor
Temnykh, A B; Temnykh, Alexander B.; Lovelace, Richard V. E.
2002-01-01
We describe a new type of magnetic field sensor which is termed an Electro-Mechanical Resonant Sensor (EMRS). The key part of this sensor is a small conductive elastic element with low damping rate and therefore a high Q fundamental mode of frequency $f_1$. An AC current is driven through the elastic element which, in the presence of a magnetic field, causes an AC force on the element. When the frequency of the AC current matches the resonant frequency of the element, maximum vibration of the element occurs and this can be measured precisely by optical means. We have built and tested a model sensor of this type using for the elastic element a length of copper wire of diameter 0.030 mm formed into a loop shape. The wire motion was measured using a light emitting diode photo-transistor assembly. This sensor demonstrated a sensitivity better than 0.001G for an applied magnetic field of $ \\sim 1$G and a good selectivity for the magnetic field direction. The sensitivity can be easily improved by a factor of $\\sim ...
Modulating the Near Field Coupling through Resonator Displacement in Planar Terahertz Metamaterials
Mohan Rao, S. Jagan; Kumar, Deepak; Kumar, Gagan; Chowdhury, Dibakar Roy
2016-10-01
We present the effect of vertical displacements between the resonators inside the unit cell of planar coupled metamaterials on their near field coupling and hence on the terahertz (THz) wave modulation. The metamolecule design consists of two planar split- ring resonators (SRRs) in a unit cell which are coupled through their near fields. The numerically simulated transmission spectrum is found to have split resonances due to the resonance mode hybridization effect. With the increase in displacement between the near field coupled SRRs, this metamaterial system shows a transition from coupled to uncoupled state through merging of the split resonances to the single intrinsic resonance. We have used a semi-analytical model describing the effect of displacements between the resonators and determine that it can predict the numerically simulated results. The outcome could be useful in modulating the terahertz waves employing near field coupled metamaterials, hence, can be useful in the development of terahertz modulators and frequency tunable devices in future.
Modulating the Near Field Coupling through Resonator Displacement in Planar Terahertz Metamaterials
Mohan Rao, S. Jagan; Kumar, Deepak; Kumar, Gagan; Chowdhury, Dibakar Roy
2017-01-01
We present the effect of vertical displacements between the resonators inside the unit cell of planar coupled metamaterials on their near field coupling and hence on the terahertz (THz) wave modulation. The metamolecule design consists of two planar split- ring resonators (SRRs) in a unit cell which are coupled through their near fields. The numerically simulated transmission spectrum is found to have split resonances due to the resonance mode hybridization effect. With the increase in displacement between the near field coupled SRRs, this metamaterial system shows a transition from coupled to uncoupled state through merging of the split resonances to the single intrinsic resonance. We have used a semi-analytical model describing the effect of displacements between the resonators and determine that it can predict the numerically simulated results. The outcome could be useful in modulating the terahertz waves employing near field coupled metamaterials, hence, can be useful in the development of terahertz modulators and frequency tunable devices in future.
Preheating after multifield inflation with nonminimal couplings, II: Resonance Structure
DeCross, Matthew P; Prabhu, Anirudh; Prescod-Weinstein, Chanda; Sfakianakis, Evangelos I
2016-01-01
This is the second in a series of papers on preheating in inflationary models comprised of multiple scalar fields coupled nonminimally to gravity. In this paper, we work in the rigid-spacetime approximation and consider field trajectories within the single-field attractor, which is a generic feature of these models. We construct the Floquet charts to find regions of parameter space in which particle production is efficient for both the adiabatic and isocurvature modes, and analyze the resonance structure using analytic and semi-analytic techniques. Particle production in the adiabatic direction is characterized by the existence of an asymptotic scaling solution at large values of the nonminimal couplings, $\\xi_I \\gg 1$, in which the dominant instability band arises in the long-wavelength limit, for comoving wavenumbers $k \\rightarrow 0$. However, the large-$\\xi_I$ regime is not reached until $\\xi_I \\geq {\\cal O} (100)$. In the intermediate regime, with $\\xi_I \\sim {\\cal O}(10)$, the resonance structure depend...
Xiong-Hua, Zheng; Bao-Fu, Zhang; Zhong-Xing, Jiao; Biao, Wang
2016-01-01
We present a continuous-wave singly-resonant optical parametric oscillator with 1.5% output coupling of the resonant signal wave, based on an angle-polished MgO-doped periodically poled lithium niobate (MgO:PPLN), pumped by a commercial Nd:YVO4 laser at 1064 nm. The output-coupled optical parametric oscillator delivers a maximum total output power of 4.19 W with 42.8% extraction efficiency, across a tuning range of 1717 nm in the near- and mid-infrared region. This indicates improvements of 1.87 W in output power, 19.1% in extraction efficiency and 213 nm in tuning range extension in comparison with the optical parametric oscillator with no output coupling, while at the expense of increasing the oscillation threshold by a factor of ˜ 2. Moreover, it is confirmed that the finite output coupling also contributes to the reduction of the thermal effects in crystal. Project supported by the National Natural Science Foundation of China (Grant Nos. 61308056, 11204044, 11232015, and 11072271), the Research Fund for the Doctoral Program of Higher Education of China (Grant Nos. 20120171110005 and 20130171130003), the Fundamental Research Funds for the Central Universities of China (Grant No. 14lgpy07), and the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory, China (Grant No. ZHD201203).
Mechanical coupling between earthquakes, volcanos and landslides
Feigl, K. L.; Retina Team
2003-04-01
"The eruption began as a large earthquake that triggered a massive landslide that culminated in a violent lateral explosion" [Malone et al., USGS 1981]. The 1980 eruption of Mount St. Helens taught a very powerful lesson -- that one natural hazard can trigger another. For example, earthquakes have triggered landslides in Papua New Guinea. Similarly, eruptions of Vesuvius are mechanically coupled to earthquakes in the Appenines, just as an inflating magma chamber can trigger earthquakes near Hengill volcano in SW Iceland and on the Izu Peninsula in Japan. The Luzon earthquake may have triggered the eruption of Mount Pinatubo. In many of these cases, the second triggered event caused more damage than the initial one. If we can better understand the mechanical coupling underlying the temporal and spatial correlation of such events, we will improve our assessments of the hazards they pose. The RETINA project has been funded by the European Commission's 5th Framework to study couplings between three classes of natural hazards: earthquakes, landslides, and volcanoes. These three phenomena are linked to and by the stress field in the crust. If the stress increases enough, the material will fail catastrophically. For example, magma injection beneath a volcano can trigger an earthquake by increasing stress on a fault. Increasing shear stress on unconsolidated materials on steep slopes can trigger landslides. Such stress change triggers may also be tectonic (from plate driving forces), hydrological (from heavy rain), or volcanic (magmatic injection). Any of these events can perturb the stress field enough to trigger another event. Indeed, stress changes as small as 0.1 bar (0.01 MPa) suffice to trigger an earthquake. If the medium is close to failure, this small change can increase the Coulomb stress beyond the yield threshold, breaking the material. This quantity is the primary means we will use for describing mechanical coupling. In this paper, we will review several case
Modulation of mechanical resonance by chemical potential oscillation in graphene
Chen, Changyao; Deshpande, Vikram V.; Koshino, Mikito; Lee, Sunwoo; Gondarenko, Alexander; MacDonald, Allan H.; Kim, Philip; Hone, James
2016-03-01
The classical picture of the force on a capacitor assumes a large density of electronic states, such that the electrochemical potential of charges added to the capacitor is given by the external electrostatic potential and the capacitance is determined purely by geometry. Here we consider capacitively driven motion of a nano-mechanical resonator with a low density of states, in which these assumptions can break down. We find three leading-order corrections to the classical picture: the first of which is a modulation in the static force due to variation in the internal chemical potential; the second and third are changes in the static force and dynamic spring constant due to the rate of change of chemical potential, expressed as the quantum (density of states) capacitance. As a demonstration, we study capacitively driven graphene mechanical resonators, where the chemical potential is modulated independently of the gate voltage using an applied magnetic field to manipulate the energy of electrons residing in discrete Landau levels. In these devices, we observe large periodic frequency shifts consistent with the three corrections to the classical picture. In devices with extremely low strain and disorder, the first correction term dominates and the resonant frequency closely follows the chemical potential. The theoretical model fits the data with only one adjustable parameter representing disorder-broadening of the Landau levels. The underlying electromechanical coupling mechanism is not limited by the particular choice of material, geometry, or mechanism for variation in the chemical potential, and can thus be extended to other low-dimensional systems.
QUANTUM MECHANICS. Quantum squeezing of motion in a mechanical resonator.
Wollman, E E; Lei, C U; Weinstein, A J; Suh, J; Kronwald, A; Marquardt, F; Clerk, A A; Schwab, K C
2015-08-28
According to quantum mechanics, a harmonic oscillator can never be completely at rest. Even in the ground state, its position will always have fluctuations, called the zero-point motion. Although the zero-point fluctuations are unavoidable, they can be manipulated. Using microwave frequency radiation pressure, we have manipulated the thermal fluctuations of a micrometer-scale mechanical resonator to produce a stationary quadrature-squeezed state with a minimum variance of 0.80 times that of the ground state. We also performed phase-sensitive, back-action evading measurements of a thermal state squeezed to 1.09 times the zero-point level. Our results are relevant to the quantum engineering of states of matter at large length scales, the study of decoherence of large quantum systems, and for the realization of ultrasensitive sensing of force and motion.
Hu, Ji-Ying; Li, Zhao-Hui; Sun, Yang; Li, Qi-Hu
2016-12-01
Shear-mode piezoelectric materials have been widely used to shunt the damping of vibrations where utilizing surface or interface shear stresses. The thick-shear mode (TSM) elastic constant and the mechanical loss factor can change correspondingly when piezoelectric materials are shunted to different electrical circuits. This phenomenon makes it possible to control the performance of a shear-mode piezoelectric damping system through designing the shunt circuit. However, due to the difficulties in directly measuring the TSM elastic constant and the mechanical loss factor of piezoelectric materials, the relationships between those parameters and the shunt circuits have rarely been investigated. In this paper, a coupling TSM electro-mechanical resonant system is proposed to indirectly measure the variations of the TSM elastic constant and the mechanical loss factor of piezoelectric materials. The main idea is to transform the variations of the TSM elastic constant and the mechanical loss factor into the changes of the easily observed resonant frequency and electrical quality factor of the coupling electro-mechanical resonator. Based on this model, the formular relationships are set up theoretically with Mason equivalent circuit method and they are validated with finite element (FE) analyses. Finally, a prototype of the coupling electro-mechanical resonator is fabricated with two shear-mode PZT5A plates to investigate the TSM elastic constants and the mechanical loss factors of different circuit-shunted cases of the piezoelectric plate. Both the resonant frequency shifts and the bandwidth changes observed in experiments are in good consistence with the theoretical and FE analyses under the same shunt conditions. The proposed coupling resonator and the obtained relationships are validated with but not limited to PZT5A. Project supported by the National Defense Foundation of China (Grant No. 9149A12050414JW02180).
Coupled mode parametric resonance in a vibrating screen model
Slepyan, Leonid I
2013-01-01
We consider a simple dynamic model of the vibrating screen operating in the parametric resonance (PR) mode. This model was used in the course of designing and setting of such a screen in LPMC. The PR-based screen compares favorably with conventional types of such machines, where the transverse oscillations are excited directly. It is characterized by larger values of the amplitude and by insensitivity to damping in a rather wide range. The model represents an initially strained system of two equal masses connected by a linearly elastic string. Self-equilibrated, longitudinal, harmonic forces act on the masses. Under certain conditions this results in transverse, finite-amplitude oscillations of the string. The problem is reduced to a system of two ordinary differential equations coupled by the geometric nonlinearity. Damping in both the transverse and longitudinal oscillations is taken into account. Free and forced oscillations of this mass-string system are examined analytically and numerically. The energy e...
ZHU Zhi-Cheng; TU Tao; GUO Guo-Ping
2011-01-01
We propose an efficient method to create multipartite spin entangled states in quantum dots coupled to a nano electro-mechanical resonator array. Our method, based on the interaction between electron spins confined in quantum dots and the motion of magnetized nano electro-mechanical resonators, can enable a coherent spin-spin coupling over long distances and in principle be applied to an arbitrarily large number of electronic spins.%@@ We propose an efficient method to create multipartite spin entangled states in quantum dots coupled to a nano electro-mechanical resonator array.Our method, based on the interaction between electron spins confined in quantum dots and the motion of magnetized nano electro-mechanical resonators, can enable a coherent spin-spin coupling over long distances and in principle be applied to an arbitrarily large number of electronic spins.
Fano-resonance induced strong-coupling of a hyperbolic cavity to a quantum emitter
Hasan, Mehedi; Belov, Pavel
2015-01-01
Light-matter interaction is studied for an open quantum system in the strong-coupling regime. A quantum dot and a hyperbolic cavity of spherical geometry is shown to couple light with large Rabi frequency and the role of Fano resonance is shown in the coupling mechanism. High Purcell factor and large Lamb shift are outlined. In the near-field spectrum, two distinct anti-crossings are evident, namely -- the one near the epsilon near zero (ENZ) frequency (from the effective medium description) which is detectable in the far-field, and the second anti-crossing is a pseudomode that does not appear in the far-field spectrum. This delineates the phenomenon `farfield propagating large Purcell factor'. Finally, we remark the fidelity of the strong-coupling, i.e. how prone the strong-coupling with respect to the loss mechanisms. This study on strong-coupling will have applications for spectroscopy, control over chemical reaction rate, microcavity, and in quantum information technology.
Gräfenstein, Jürgen; Tuttle, Tell; Cremer, Dieter
2004-06-01
The theory of the J-OC-PSP (decomposition of J into orbital contributions using orbital currents and partial spin polarization) method is derived to distinguish between the role of active, passive, and frozen orbitals on the nuclear magnetic resonance (NMR) spin-spin coupling mechanism. Application of J-OC-PSP to the NMR spin-spin coupling constants of ethylene, which are calculated using coupled perturbed density functional theory in connection with the B3LYP hybrid functional and a [7s,6p,2d/4s,2p] basis set, reveal that the well-known pi mechanism for Fermi contact (FC) spin coupling is based on passive pi orbital contributions. The pi orbitals contribute to the spin polarization of the sigma orbitals at the coupling nuclei by mediating spin information between sigma orbitals (spin-transport mechanism) or by increasing the spin information of a sigma orbital by an echo effect. The calculated FC(pi) value of the SSCC (1)J(CC) of ethylene is 4.5 Hz and by this clearly smaller than previously assumed.
Single-photon all-optical switching using coupled microring resonators
Wenge Yang; Amitabh Joshi; Min Xiao
2007-08-01
We study the nonlinear phase response of a microring resonator coupled to a bus waveguide and the use of this nonlinear phase shift to store information in the microring resonator and enhance the switching characteristics of a Mach–Zehnder interferometer (MZI). By introducing coupling between adjacent microring resonators, the switching characteristics of the MZI can be exponentially enhanced as a function of the number of microring resonators, when compared to the linear enhancement for uncoupled resonators. With only a few moderate-finesse microring resonators, the switching power can be reduced to attowatt level, allowing for photonic switching devices that operate at single-photon level in ordinary optical waveguides.
Korn, Matthias; Umathum, Reiner; Schulz, Jessica; Semmler, Wolfhard; Bock, Michael
2011-03-01
An inductively coupled coil concept is presented, which improves the compensation of physiological motion by the self-gating (SG) technique. The animal is positioned in a conventional volume coil encompassing the whole animal. A small, resonant surface coil (SG-coil) is placed on the thorax so that its sensitive region includes the heart. Via inductive coupling the SG-coil amplifies selectively the MR signal of the beating heart. With an optical detuning mechanism, this coupling can be switched off during acquisition of the MR image information, whereas it is active during SG data sampling to provide the physiological information. In vivo experiments on a mouse show an amplification of the SG signal by at least 40%. Copyright © 2010 Wiley-Liss, Inc.
Strong and Coherent Coupling of a Plasmonic Nanoparticle to a Subwavelength Fabry-Pérot Resonator.
Konrad, Alexander; Kern, Andreas M; Brecht, Marc; Meixner, Alfred J
2015-07-08
A major aim in experimental nano- and quantum optics is observing and controlling the interaction between light and matter on a microscopic scale. Coupling molecules or atoms to optical microresonators is a prominent method to alter their optical properties such as luminescence spectra or lifetimes. Until today strong coupling of optical resonators to such objects has only been observed with atom-like systems in high quality resonators. We demonstrate first experiments revealing strong coupling between individual plasmonic gold nanorods (GNR) and a tunable low quality resonator by observing cavity-length-dependent nonlinear dephasing and spectral shifts indicating spectral anticrossing of the luminescent coupled system. These phenomena and experimental results can be described by a model of two coupled oscillators representing the plasmon resonance of the GNR and the optical fields of the resonator. The presented reproducible and accurately tunable resonator allows us to precisely control the optical properties of individual particles.
Multiple Resonance and Stability of a Motor-elastic Linkage Mechanism System
LI Zhao-jun; CAI Gan-wei; DAI Wen-zheng
2006-01-01
The dynamics of a three-phase AC motor-elastic linkage mechanism system is considered. Taking the drive motor and the linkage mechanism as an integrated system, the coupling dynamic equations of the system are established by the finite element method. The multiple resonance and its stability of the system are studied using the method of multiple scales. The first order approximate solutions of the multiple resonance of the system are obtained. An algorithm for determining the stability of resonance is derived. The studies show that the multiple resonance and its stability of the system are not only related to the structure parameters of the linkage mechanism, but also to the electromagnetism parameters of the motor. At last, an experiment is given to verify the results of the theoretical analysis.
Identification of matrix conditions that give rise to the linear coupling resonances
Gardner,C.J.
2009-03-01
General definitions of horizontal and vertical amplitudes for linear coupled motion are developed from the normal form of the one-turn matrix. This leads to the identification of conditions on the matrix that give rise to the linear coupling sum and difference resonances. The correspondence with the standard hamiltonian treatment of the resonances is discussed.
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.
Inequivalence of direct and converse magnetoelectric coupling at electromechanical resonance
Wu, Gaojian; Nan, Tianxiang; Zhang, Ru; Zhang, Ning; Li, Shandong; Sun, Nian X.
2013-10-01
Resonant direct and converse magnetoelectric (ME) effects have been investigated experimentally and theoretically in FeGa/PZT/FeGa sandwich laminate composites under the same electric and magnetic bias conditions. Resonant direct ME effect (DME) occurs at antiresonance frequency while resonant converse ME effect (CME) occurs at resonance frequency. The antiresonance and resonance frequencies have close but different values under identical bias conditions. The magnitudes of resonant effective ME coefficients for direct and converse ME effects are also not equal. A model was developed to describe the frequency response of DME and CME in laminate composite, which was in good agreement with experimental results.
Schneeweiss, Philipp; Hoinkes, Thomas; Rauschenbeutel, Arno; Volz, Jürgen
2016-01-01
We experimentally realize an optical fiber ring resonator that includes a tapered section with subwavelength-diameter waist. In this section, the guided light exhibits a significant evanescent field which allows for efficient interfacing with optical emitters. A commercial tunable fiber beam splitter provides simple and robust coupling to the resonator. Key parameters of the resonator such as its out-coupling rate, free spectral range, and birefringence can be adjusted. Thanks to the low taper- and coupling-losses, the resonator exhibits an unloaded finesse of F=75+/-1, sufficient for reaching the regime of strong coupling for emitters placed in the evanescent field. The system is ideally suited for trapping ensembles of laser-cooled atoms along the nanofiber section. Based on measured parameters, we estimate that the system can serve as a platform for optical multimode strong coupling experiments. Finally, we discuss the possibilities of using the resonator for applications based on chiral quantum optics.
Graphene-based electromagnetically induced transparency with coupling Fabry-Perot resonators.
Zhuang, Huawei; Kong, Fanmin; Li, Kang; Sheng, Shiwei
2015-08-20
We investigate the plasmonic analog of electromagnetically induced transparency (EIT) using two adjacent graphene-based Fabry-Perot (F-P) resonators side coupling to a nanoribbon waveguide. By the coupling mode theory in time and F-P resonant model, the destructive interference from the coupling of the two F-P resonators results in the EIT-like optical response. The induced peak and width of the transparency window can be dynamically manipulated by varying the coupling distance of the two resonators, and the transparent window is easily shifted by tuning the resonator length or the chemical potential of the graphene nanoribbon. In order to verify the characteristics of slow light, the group index profile is analyzed at different coupling distances. The proposed graphene-based EIT-like system could open up new opportunities for potential applications in plasmonic slow light and optical information buffering devices.
46 CFR 56.30-35 - Gasketed mechanical couplings.
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Gasketed mechanical couplings. 56.30-35 Section 56.30-35... APPURTENANCES Selection and Limitations of Piping Joints § 56.30-35 Gasketed mechanical couplings. (a) This... Inspection. (b) Gasketed mechanical couplings may be used within the service limitations of...
Nonlinear mode coupling and internal resonances in MoS2 nanoelectromechanical system
Samanta, C.; Yasasvi Gangavarapu, P. R.; Naik, A. K.
2015-10-01
Atomically thin two dimensional (2D) layered materials have emerged as a new class of material for nanoelectromechanical systems (NEMS) due to their extraordinary mechanical properties and ultralow mass density. Among them, graphene has been the material of choice for nanomechanical resonator. However, recent interest in 2D chalcogenide compounds has also spurred research in using materials such as MoS2 for the NEMS applications. As the dimensions of devices fabricated using these materials shrink down to atomically thin membrane, strain and nonlinear effects have become important. A clear understanding of the nonlinear effects and the ability to manipulate them is essential for next generation sensors. Here, we report on all electrical actuation and detection of few-layer MoS2 resonator. The ability to electrically detect multiple modes and actuate the modes deep into the nonlinear regime enables us to probe the nonlinear coupling between various vibrational modes. The modal coupling in our device is strong enough to detect three distinct internal resonances.
Parallel-coupled dual racetrack silicon micro-resonators for quadrature amplitude modulation.
Integlia, Ryan A; Yin, Lianghong; Ding, Duo; Pan, David Z; Gill, Douglas M; Jiang, Wei
2011-08-01
A parallel-coupled dual racetrack silicon micro-resonator structure is proposed and analyzed for M-ary quadrature amplitude modulation. The over-coupled, critically coupled, and under-coupled scenarios are systematically studied. Simulations indicate that only the over-coupled structures can generate arbitrary M-ary quadrature signals. Analytic study shows that the large dynamic range of amplitude and phase of a modulated over-coupled structure stems from the strong cross-coupling between two resonators, which can be understood through a delicate balance between the direct sum and the "interaction" terms. Potential asymmetries in the coupling constants and quality factors of the resonators are systematically studied. Compensations for these asymmetries by phase adjustment are shown feasible.
Issues in nanophotonics: coupling and phase in resonant tunneling
Tsu, Raphael
2013-01-01
Modern Nano electronics involves the use of heterojunctions in forming energy steps based on band-edge alignments in effecting quantum confinements. When the electron meanfree- path exceeds couple of periods, man-made quantum states appeared, mimicking natural solids with sharpness determined by the degree of coherence dictated by a relatively long meanfree- path. When a single quantum well is involved, the structure is represented by resonant tunneling. This process can further be extended to 3D (3-dimension), known as QD, for quantum dot, however, thus far only few systems have been found possible, mostly involving InAs, or InN. However, the real problem lies in I/O, making contact to a single quantum dot, seems to be impractical on account of difficulties in making contacts in Nano scale regime. The issue with impedance matching, is the most important aspect for efficient devices, whether as detectors, or as generator in frequencies between THz to visible light. As size shrinks to Nano-regime, even the wavelength of IR is too large for effective coupling to the quantum dots without some sort of coupling such as the use of Fabry-Perrot mirrors, which is in fact unsuited for quantum dots, unless these dots are arranged in an array mimicking a solid with translational symmetry, which in fact defeating the purpose of going to quantum dots, except when the distribution of these quantum dots are arranged either representable by some distribution functions suitable for arriving at a meaningful average, or periodically mimicking a solid, such as the man-made superlattice, SL, originally proposed by Esaki and Tsu. [1, 2]. Interestingly Esaki and Tsu were asked to remove the reference on doping in the barrier region for increased mobility by the reviewer for the IBM's own J. of Research and Development. We did protest to the Editor-in- Chief of the Journal to no avail! Because of this experience, it did occur to me of requiring something beyond the regular reviewing
Li, Hai-ming; Liu, Shao-bin, E-mail: lsb@nuaa.edu.cn; Liu, Si-yuan; Zhang, Hai-feng; Bian, Bo-rui; Kong, Xiang-kun [Key Laboratory of Radar Imaging and Microwave Photonics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Wang, Shen-yun [Research Center of Applied Electromagnetics, Nanjing University of Information Science and Technology, Nanjing 210044 (China)
2015-03-16
In this paper, we numerically and experimentally demonstrate electromagnetically induced transparency (EIT)-like spectral response with magnetic resonance near field coupling to electric resonance. Six split-ring resonators and a cut wire are chosen as the bright and dark resonator, respectively. An EIT-like transmission peak located between two dips can be observed with incident magnetic field excitation. A large delay bandwidth product (0.39) is obtained, which has potential application in quantum optics and communications. The experimental results are in good agreement with simulated results.
Research on Resonance Mechanism of Arc-ultrasonic
无
2000-01-01
@@As a transmission medium, welding arc can be modulated to emit ultrasonic energy by exerting high-frequency electric current. The frequency of exciting electric current has notable influence on the signals recorded by the sensors and the metallographic structures of the welds. The resonance phenomenon of arc-ultrasonic has been found in the experiment. Both the resonance mechanism and the distribution of resonance frequency are discussed by the built vibration equation.
Electrically small, complementary electric-field-coupled resonator antennas
Odabasi, H.; Teixeira, F. L.; Guney, D. O.
2013-02-01
We study the radiation properties of electrically small resonant antennas (ka CELC) resonators and a monopole antenna. We use such parasitic ELC and CELC "metaresonators" to design various electrically small antennas. In particular, monopole-excited and bent-monopole-excited CELC resonator antennas are proposed that provide very low profiles on the order of λ0/20. We compare the performance of the proposed ELC and CELC antennas against more conventional designs based upon split-ring resonators.
Pishko, Svetlana V; Benson, Trevor M; Boriskina, Svetlana V
2007-01-01
Waveguides composed of electromagnetically-coupled optical microcavities (coupled resonator optical waveguides or CROWs) can be used for light guiding, slowing and storage. In this paper, we present a two-dimensional analysis of finite-size straight and curved CROW sections based on a rigorous Muller boundary integral equations method. We study mechanisms of the coupling of whispering gallery (WG) modes and guiding light around bends in CROWs composed of both identical and size-mismatched microdisk resonators. Our accurate analysis reveals differences in WG modes coupling in the vicinity of bends in CROWs composed of optically-large and wavelength-scale microcavities. We propose and discuss possible ways to design low-loss CROW bends and to reduce bend losses. These include selecting specific bend angles depending on the azimuthal order of the WG mode and tuning the radius of the microdisk positioned at the CROW bend.
Crosstalk-insensitive method for simultaneously coupling multiple pairs of resonators
Yang, Chui-Ping; Su, Qi-Ping; Zheng, Shi-Biao; Nori, Franco
2016-04-01
In a circuit consisting of two or more resonators, the intercavity crosstalk is inevitable, which could create some problems, such as degrading the performance of quantum operations and the fidelity of various quantum states. The focus of this work is to propose a crosstalk-insensitive method for simultaneously coupling multiple pairs of resonators, which is important in large-scale quantum information processing and communication in a network consisting of resonators or cavities. In this work, we consider 2 N resonators of different frequencies, which are coupled to a three-level quantum system (qutrit). By applying a strong pulse to the coupler qutrit, we show that an effective Hamiltonian can be constructed for simultaneously coupling multiple pairs of resonators. The main advantage of this proposal is that the effect of inter-resonator crosstalks is greatly suppressed by using resonators of different frequencies. In addition, by employing the qutrit-resonator dispersive interaction, the intermediate higher-energy level of the qutrit is virtually excited and thus decoherence from this level is suppressed. This effective Hamiltonian can be applied to implement quantum operations with photonic qubits distributed in different resonators. As one application of this Hamiltonian, we show how to simultaneously generate multiple Einstein-Podolsky-Rosen pairs of photonic qubits distributed in 2 N resonators. Numerical simulations show that it is feasible to prepare two high-fidelity EPR photonic pairs using a setup of four one-dimensional transmission line resonators coupled to a superconducting flux qutrit with current circuit QED technology.
Nonlinear mechanical resonators for ultra-sensitive mass detection
Datskos, Panos G [ORNL; Lavrik, Nickolay V [ORNL
2014-01-01
The fundamental sensitivity limit of an appropriately scaled down mechanical resonator can approach one atomic mass unit when only thermal noise is present in the system. However, operation of such nanoscale mechanical resonators is very challenging due to minuteness of their oscillation amplitudes and presence of multiple noise sources in real experimental environments. In order to surmount these challenges, we use microscale cantilever resonators driven to large amplitudes, far beyond their nonlinear instability onset. Our experiments show that such a nonlinear cantilever resonator, described analytically as a Duffing oscillator, has mass sensing performance comparable to that of much smaller resonators operating in a linear regime. We demonstrate femtogram level mass sensing that relies on a bifurcation point tracking that does not require any complex readout means. Our approaches enable straightforward detection of mass changes that are near the fundamental limit imposed by thermo-mechanical fluctuations.
Mechanics of coupled granular/fluid flows
Vinningland, J.; Toussaint, R.; Johnsen, O.; Flekkoy, E. G.; Maloy, K. J.
2006-12-01
We introduce a hybrid numerical model for coupled flow of solid grains and intersticial fluid, which renders for complex hydrodynamic interactions between mobile grains. This model treats the solid phase as discrete particles, interacting mechanically with the other particles and with the intersticial flowing fluid. The fluid is described by continuum equations rendering for its advection by the local grains, superposed to a pressure diffusion ruled by a Darcy flow with a permeability depending on the local solid fraction. This model is aimed at describing accurately such coupled flow. This model is tested for two model situations, where it is compared to experimental results: 1/ Injection of a localized overpressure in a grain/fluid filled cell lying horizontally, where gravity is unimportant. 2/ Sedimentation of heavy grains falling into an initially grain-free fluid region. The development of pattern-forming instabilities is obtained in these two situations, corresponding to granular/fluid equivalents of the two-fluids Saffman-Taylor and Rayleigh-Taylor instabilities. Numerical and experimental results are shown to be consistent with each other.
Electric-field-induced interferometric resonance of a one-dimensional spin-orbit-coupled electron
Fan, Jingtao; Chen, Yuansen; Chen, Gang; Xiao, Liantuan; Jia, Suotang; Nori, Franco
2016-01-01
The efficient control of electron spins is of crucial importance for spintronics, quantum metrology, and quantum information processing. We theoretically formulate an electric mechanism to probe the electron spin dynamics, by focusing on a one-dimensional spin-orbit-coupled nanowire quantum dot. Owing to the existence of spin-orbit coupling and a pulsed electric field, different spin-orbit states are shown to interfere with each other, generating intriguing interference-resonant patterns. We also reveal that an in-plane magnetic field does not affect the interval of any neighboring resonant peaks, but contributes a weak shift of each peak, which is sensitive to the direction of the magnetic field. We find that this proposed external-field-controlled scheme should be regarded as a new type of quantum-dot-based interferometry. This interferometry has potential applications in precise measurements of relevant experimental parameters, such as the Rashba and Dresselhaus spin-orbit-coupling strengths, as well as the Landé factor. PMID:27966598
Electric-field-induced interferometric resonance of a one-dimensional spin-orbit-coupled electron
Fan, Jingtao; Chen, Yuansen; Chen, Gang; Xiao, Liantuan; Jia, Suotang; Nori, Franco
2016-12-01
The efficient control of electron spins is of crucial importance for spintronics, quantum metrology, and quantum information processing. We theoretically formulate an electric mechanism to probe the electron spin dynamics, by focusing on a one-dimensional spin-orbit-coupled nanowire quantum dot. Owing to the existence of spin-orbit coupling and a pulsed electric field, different spin-orbit states are shown to interfere with each other, generating intriguing interference-resonant patterns. We also reveal that an in-plane magnetic field does not affect the interval of any neighboring resonant peaks, but contributes a weak shift of each peak, which is sensitive to the direction of the magnetic field. We find that this proposed external-field-controlled scheme should be regarded as a new type of quantum-dot-based interferometry. This interferometry has potential applications in precise measurements of relevant experimental parameters, such as the Rashba and Dresselhaus spin-orbit-coupling strengths, as well as the Landé factor.
Xianshu Luo; Andrew W. Poon
2009-01-01
We propose novel double-notch-shaped microdisk resonator-based devices with gapless waveguide-to- microdisk and inter-cavity coupling via the two notches of the microdisk. Both finite-difference time- domain simulations and experimental demonstrations reveal the high-quality-factor multimode resonances in such microdisks. Using such double-notch microdisk resonators, we experimentally demonstrate the many-element linearly cascaded-microdisk resonator devices with up to 50 elements on a silicon chip.
Mode coupling control in a resonant device: application to solid-state ring lasers
Schwartz, Sylvain; Feugnet, Gilles; Bouyer, Philippe; Lariontsev, Evguenii; Aspect, Alain; Pocholle, Jean-Paul
2006-01-01
International audience; A theoretical and experimental investigation of the effects of mode coupling in a resonant macro- scopic quantum device is achieved in the case of a ring laser. In particular, we show both analytically and experimentally that such a device can be used as a rotation sensor provided the effects of mode coupling are controlled, for example through the use of an additional coupling. A possible general- ization of this example to the case of another resonant macroscopic qua...
Finite element modeling of coupled optical microdisk resonators for displacement sensing
Grudinin, Ivan
2012-01-01
We analyze normal mode splitting in a pair of vertically coupled microdisk resonators. A full vectorial finite element model is used to find the eigen frequencies of the symmetric and antisymmetric composite modes as a function of coupling distance. We find that the coupled microdisks can compete with the best Fabry-Perot resonators in displacement sensing. We also show how we configured FreeFem++ for the sphere eigenvalue problem.
Resonance light scattering determination of 6-mercaptopurine coupled with HPLC technique
Li, Ai Ping; Peng, Jing Dong; Zhou, MingQiong; Zhang, Jin
2016-02-01
A simple, fast, costless, sensitive and selective method of resonance light scattering coupled with HPLC was established for the determination of 6-mercaptopurine in human urine sample. In a Britton-Robinson buffer solution of pH 5.5, the formation of coordination complex between 6-mercaptopurine and metal palladium (II) led to enhance the RLS intensity of the system. The RLS signal was detected by fluorescence detector at λex = λem = 315 nm. The analytical parameters were provided by the coupled system, the linear of 6-mercaptopurine response from 0.0615 to 2.40 μg L- 1 and the limit of detection (S/N = 3) was 0.05 μg L- 1. The presented method has been applied to determine 6-mercaptopurine in human urine samples which obtained satisfactory results. Moreover, the reaction mechanism and possible reasons for enhancement of RLS were fully discussed.
Fan, Guofang; Li, Yuan; Hu, Chunguang; Lei, Lihua; Guo, Yanchuan
2016-08-01
A novel process to control light through the coupling modulation by surface acoustic wave (SAW) is presented in an optical micro resonator. An optical waveguide modulator of a racetrack resonator on silicon-on-insulator (SOI) technology is took as an example to explore the mechanism. A finite-difference time-domain (FDTD) is developed to simulate the acousto-optical (AO) modulator using the mechanism. An analytical method is presented to verify our proposal. The results show that the process can work well as an optical modulator by SAW.
Single Element Excitation and Detection of (Micro-)Mechanical Resonators
Tilmans, Harrie A.C.; IJntema, Dominicus .J.; Fluitman, Jan H.J
1991-01-01
The authors describe a single-element approach for the excitation and detection of the vibrational motion of (micro-)mechanical resonators. An equivalent electrical one-port network is derived for an electrostatically and a piezoelectrically driven resonator. In this way, the effect of the mechanica
Zhou, L; Sun, C P; Lu, Jing; Zhou, Lan
2006-01-01
In the first paper of our series of articles on photon transmission in the coupled resonator optical waveguide (CROW), we used the two time Green function approach to study the physical mechanism for the coherent control by doping two-level atoms. In present paper, we propose and study a hybrid mechanism for photon transmission in the CROW by incorporating the electromagnetically induced transparency (EIT) effect in the doping artificial atoms and the band structure of the CROW. Here, the configuration setup of system, similar to that in the first paper, consists of a CROW with homogeneous couplings and the artificial atoms with $\\Lambda$-type three levels doped in each cavity. Unlike the stimulated Raman process used in the first paper to reduce the three level systems into the two level ones, the roles of three levels are completely considered based on a kind of mean field approach where the collection of three-level atoms collectively behave as two-mode spin waves. Then the total system is reduced into an ...
Quantum force of tunneling macrospins with a mechanical resonator
Kim, Gwang-Hee
2017-09-01
We study force dynamics of macropsin of molecular magnets coupled to a torsional resonator. In the presence of an ac field and a static field with a gradient, the force is shown to display various types of quantum oscillations which depend upon the coupling strength and the frequency of torsional oscillations. Optimal conditions for observing them will be discussed within the framework of experimentally controllable parameters.
Observation of decoherence in a carbon nanotube mechanical resonator.
Schneider, Ben H; Singh, Vibhor; Venstra, Warner J; Meerwaldt, Harold B; Steele, Gary A
2014-12-19
In physical systems, decoherence can arise from both dissipative and dephasing processes. In mechanical resonators, the driven frequency response measures a combination of both, whereas time-domain techniques such as ringdown measurements can separate the two. Here we report the first observation of the mechanical ringdown of a carbon nanotube mechanical resonator. Comparing the mechanical quality factor obtained from frequency- and time-domain measurements, we find a spectral quality factor four times smaller than that measured in ringdown, demonstrating dephasing-induced decoherence of the nanomechanical motion. This decoherence is seen to arise at high driving amplitudes, pointing to a nonlinear dephasing mechanism. Our results highlight the importance of time-domain techniques for understanding dissipation in nanomechanical resonators, and the relevance of decoherence mechanisms in nanotube mechanics.
Observation of decoherence in a carbon nanotube mechanical resonator
Schneider, Ben H.; Singh, Vibhor; Venstra, Warner J.; Meerwaldt, Harold B.; Steele, Gary A.
2014-12-01
In physical systems, decoherence can arise from both dissipative and dephasing processes. In mechanical resonators, the driven frequency response measures a combination of both, whereas time-domain techniques such as ringdown measurements can separate the two. Here we report the first observation of the mechanical ringdown of a carbon nanotube mechanical resonator. Comparing the mechanical quality factor obtained from frequency- and time-domain measurements, we find a spectral quality factor four times smaller than that measured in ringdown, demonstrating dephasing-induced decoherence of the nanomechanical motion. This decoherence is seen to arise at high driving amplitudes, pointing to a nonlinear dephasing mechanism. Our results highlight the importance of time-domain techniques for understanding dissipation in nanomechanical resonators, and the relevance of decoherence mechanisms in nanotube mechanics.
Mechanism of Edge Localized Mode Mitigation by Resonant Magnetic Perturbations
Bécoulet, M.; Orain, F.; Huijsmans, G. T. A.; Pamela, S.; Cahyna, P.; Hoelzl, M.; Garbet, X.; Franck, E.; Sonnendrücker, E.; Dif-Pradalier, G.; Passeron, C.; Latu, G.; Morales, J.; Nardon, E.; Fil, A.; Nkonga, B.; Ratnani, A.; Grandgirard, V.
2014-09-01
A possible mechanism of edge localized modes (ELMs) mitigation by resonant magnetic perturbations (RMPs) is proposed based on the results of nonlinear resistive magnetohydrodynamic modeling using the jorek code, realistic JET-like plasma parameters and an RMP spectrum of JET error-field correction coils (EFCC) with a main toroidal number n =2 were used in the simulations. Without RMPs, a large ELM relaxation is obtained mainly due to the most unstable medium-n ballooning mode. The externally imposed RMP drives nonlinearly the modes coupled to n =2 RMP which produce small multimode relaxations, mitigated ELMs. The modes driven by RMPs exhibit a tearinglike structure and produce additional islands. Mitigated ELMs deposit energy into the divertor mainly in the structures ("footprints") created by n =2 RMPs, however, slightly modulated by other nonlinearly driven even harmonics. The divertor power flux during a ELM phase mitigated by RMPs is reduced almost by a factor of 10. The mechanism of ELM mitigation by RMPs proposed here reproduces generic features of high collisionality RMP experiments, where large ELMs are replaced by small, much more frequent ELMs or magnetic turbulence. Total ELM suppression was also demonstrated in modeling at higher RMP amplitude.
Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim
2009-01-01
It has been shown previously that surface acoustic waves can be efficiently trapped and slowed by steep ridges on a piezoelectric substrate, giving rise to two families of shear-horizontal and vertically polarized surface waves. The mechanisms of energy storage and dispersion are explored by using...... as resonators storing mechanical energy. These resonators are evanescently coupled by the surface. The dispersion diagram is presented and shows very low group velocities as the wave vector approaches the limit of the first Brillouin zone. ©2009 American Institute of Physics...
Internal stochastic resonance in two coupled chemical oscil-lators
ZHONG; Shi
2001-01-01
［1］Sears, T. J., The calculation of the energy levels of an asymmetric top free radical in a magnetic field, Comput. Phys. Rep., 1984, 2: 1..［2］Davies, P. B., Liu, Y., Liu, Z., Far infrared LMR spectra of monobromomethyl radicals, Chem. Phys. Lett., 1993, 214: 305.［3］Nolte, J., Wagner, H. G., Sears, T. J. et al., The far-infrared laser magnetic resonance spectrum of CH2F, J. Mol. Spec-trosc., 1999, 195: 43.［4］Sears, T. J., ASYTOP--A program for detailed analysis of gas phase magnetic resonance spectra of asymmetric top molecules, Comput. Phys. Commun., 1984, 34: 123.［5］Papousek, D., Aliev, M. R., Molecular Vibrational Rotational Spectra, Prague: Academia, 1982, 72.［6］Matsushima, F., Nagase, H., Nakauchi, T. et al., Frequency measurement of pure rotational transitions of H2O, J. Mol. Spectrosc., 1999, 193: 217.［7］Bowater, I. C., Brown, J. M., Carrington, A., Microwave spectroscopy of nonlinear free radicals, Proc. R. Soc. Lond. A, 1973, 333: 265.［8］Castellano, S., Bothner-by, A. A., Analysis of NMR spectra by least squares, J. Chem. Phys., 1964, 41: 3863.［9］Bird, G. R., Microwave spectrum of NO2, J. Chem. Phys., 1956, 25: 1040.［10］Bird, G. R., Baird, J. C., Jache, A. W. et al., Microwave spectrum of NO2: fine structure and magnetic coupling, J. Chem. Phys., 1964, 40: 3378.［11］Lees, R. M., Curl, R. F., Baker, J. G., Millimeter-wavelength microwave spectrum of nitrogen dioxide, J. Chem. Phys., 1966, 45: 2037.［12］Baron, P. A., Godfrey, P. D., Harris, D. O., Microwave spectrum of NO2 at 70 GHz, J. Chem. Phys., 1974, 60: 3723.［13］Bowman, W. C., De Lucia, F. C., The millimeter and submillimeter spectrum of NO2, J. Chem. Phys., 1982, 77: 92.［14］Semmoud-Monnanteuil, N., Colmont, J. M., Perrin, A. et al., New measurements in the millimeter-wave spectrum of NO2, J. Mol. Spectrosc., 1989, 134: 176.［15］Baskakov, O. I., Moskienko, M. V., Dyubko, S. F., Submillimeter rotational spectrum of nitrogen dioxide, Opt
On non-linear dynamics of a coupled electro-mechanical system
Darula, Radoslav; Sorokin, Sergey
2012-01-01
, for mechanical system, is of the second order. The governing equations are coupled via linear and weakly non-linear terms. A classical perturbation method, a method of multiple scales, is used to find a steadystate response of the electro-mechanical system exposed to a harmonic close-resonance mechanical......Electro-mechanical devices are an example of coupled multi-disciplinary weakly non-linear systems. Dynamics of such systems is described in this paper by means of two mutually coupled differential equations. The first one, describing an electrical system, is of the first order and the second one...... excitation. The results are verified using a numerical model created in MATLAB Simulink environment. Effect of non-linear terms on dynamical response of the coupled system is investigated; the backbone and envelope curves are analyzed. The two phenomena, which exist in the electro-mechanical system: (a...
Nonlinear Resonance of Mechanically Excited Sessile Drops
Chang, Chun-Ti; Daniel, Susan; Steen, Paul
2013-11-01
The spectrum of frequencies and mode shapes for an inviscid drop on a planar substrate have recently been documented. For vertical excitation, zonal modes respond to the driving frequency harmonically and non-zonal modes subharmonically, consistent with the prior literature. In this study, we report observations from the regime of nonlinear response. Here, zonals can respond non-harmonically, both sub- and super-harmonic responses are reported. The principal challenge to generating and observing superharmonic resonances of higher zonal modes is a mode-mixing behavior. However, using a simple visual simulation based on the ray-tracing technique, the individual contributions to the mixed resonance behavior can be extracted. In summary, results from experiment and theory show that the zonal modes, which respond harmonically and can mix with non-zonal modes without interfering with one another in the linear regime, tend to respond sub- or superharmonically and compete with non-zonal modes in the nonlinear regime.
Resonator Coupling of Two Ring Cavity, Argon-Ion Lasers.
1987-12-01
mirrors CMi and CM2, which coupled the backward traveling-waves, and coupling beamsplitters CB1 and CB2 , which coupled the forward traveling waves...these elements were replaced with flat, 32% beamsplitters. Alignment of beamsplitters CB1 and CB2 was difficult because each output beam was...Output Couplers--- --- CM2 C B 1 CB2 Figure 4: Orientation of Coupling Beamsplitters. Coupling beamsplitters CB1 and CB2 were roughly aligned such that
Analysis of resonance mechanism and conditions of train bridge system
Xia, H.; Zhang, N.; Guo, W. W.
2006-11-01
In this paper, the resonance mechanism and conditions of train-bridge system are investigated through theoretical derivations, numerical simulations and experimental data analyses. The resonant responses of the bridge induced by moving trains are classified into three types according to different resonance mechanisms: the first is related to the periodical actions of moving load series of the vertical weights, lateral centrifugal and wind forces of vehicles; the second is induced by the loading rate of moving load series of vehicles; the third is owing to the periodically loading of the swing forces of the train vehicles excited by track irregularities and wheel hunting movements. The vehicle resonance is induced by the periodical action of regular arrangement of bridge spans and their deflections. The resonant conditions are proposed and the corresponding resonant train speeds are determined. The application scopes of resonance conditions are discussed. The resonance of the train-bridge system is affected by the span, total length, lateral and vertical stiffness of the bridge, the compositions of the train, and the axle arrangements and natural frequencies of the vehicles. The resonant train speeds for some bridges are estimated and are compared with the critical train speeds obtained from the dynamic simulation of train-bridge interaction model or from the field measurements.
Plasmon coupling of magnetic resonances in an asymmetric gold semishell
Ye, Jian; Kong, Yan; Liu, Cheng
2016-05-01
The generation of magnetic dipole resonances in metallic nanostructures is of great importance for constructing near-zero or even negative refractive index metamaterials. Commonly, planar two-dimensional (2D) split-ring resonators or relevant structures are basic elements of metamaterials. In this work, we introduce a three-dimensional (3D) asymmetric Au semishell composed of two nanocups with a face-to-face geometry and demonstrate two distinct magnetic resonances spontaneously in the visible-near infrared optical wavelength regime. These two magnetic resonances are from constructive and destructive hybridization of magnetic dipoles of individual nanocups in the asymmetric semishell. In contrast, complete cancellation of magnetic dipoles in the symmetric semishell leads to only a pronounced electric mode with near-zero magnetic dipole moment. These 3D asymmetric resonators provide new ways for engineering hybrid resonant modes and ultra-high near-field enhancement for the design of 3D metamaterials.
Characterization of the non-resonant radiation damping in coupled cavity photon magnon system
Rao, J. W.; Kaur, S.; Fan, X. L.; Xue, D. S.; Yao, B. M.; Gui, Y. S.; Hu, C.-M.
2017-06-01
We have experimentally investigated the non-resonant radiation damping in the coupled cavity photon-magnon system in addition to the resonant radiation damping which results in the linewidth exchange between the magnon-like and photon-like hybrid modes. The contribution of this non-resonant effect becomes apparent when the cavity photon-magnon resonance frequencies are mismatched. By carefully examining the change in the linewidth and the shift in the magnon resonance as a function of the coupling strength between the cavity photons and magnons, we can quantitatively describe this non-resonant radiation damping by including an additional relaxation channel for the hybridized photon-magnon system. This experimental realization and theoretical modelling of the non-resonant radiation damping in the cavity photon-magnon system may help in the design and adaptation of these systems for practical applications.
Zhang, Sheng; Rao, Jia-Yu; Tai, Wen-Si; Wang, Ting; Liu, Fa-Lin
2016-09-01
In this paper, a kind of quasi eighth substrate integrated waveguide resonator (QESIWR) with defected fractal structure (DFS) is proposed firstly. Compared with the eighth substrate integrated waveguide resonator (ESIWR), this kind of resonator has lower resonant frequency (f0), acceptable unloaded quality (Qu) value and almost unchanged electric field distribution. In order to validate the properties of QESIWR, a cascaded quadruplet QESIWRs filter is designed and optimized. By using cross coupling and gap coupling compensation, this filter has two transmission zeros (TZs) at each side of the passband. Meanwhile, in comparison with the conventional ones, its size is cut down over 90 %. The measured results agree well with the simulated ones.
Cavity-mediated coupling of mechanical oscillators limited by quantum backaction
Spethmann, Nicolas; Schreppler, Sydney; Buchmann, Lukas; Stamper-Kurn, Dan M
2015-01-01
A complex quantum system can be constructed by coupling simple quantum elements to one another. For example, trapped-ion or superconducting quantum bits may be coupled by Coulomb interactions, mediated by the exchange of virtual photons. Alternatively quantum objects can be coupled by the exchange of real photons, particularly when driven within resonators that amplify interactions with a single electro-magnetic mode. However, in such an open system, the capacity of a coupling channel to convey quantum information or generate entanglement may be compromised. Here, we realize phase-coherent interactions between two spatially separated, near-ground-state mechanical oscillators within a driven optical cavity. We observe also the noise imparted by the optical coupling, which results in correlated mechanical fluctuations of the two oscillators. Achieving the quantum backaction dominated regime opens the door to numerous applications of cavity optomechanics with a complex mechanical system. Our results thereby illu...
Vertically-coupled Whispering Gallery Mode Resonator Optical Waveguide, and Methods
Matsko, Andrey B. (Inventor); Savchenkov, Anatolly A. (Inventor); Matleki, Lute (Inventor)
2007-01-01
A vertically-coupled whispering gallery mode (WGM) resonator optical waveguide, a method of reducing a group velocity of light, and a method of making a waveguide are provided. The vertically-coupled WGM waveguide comprises a cylindrical rod portion having a round cross-section and an outer surface. First and second ring-shaped resonators are formed on the outer surface of the cylindrical rod portion and are spaced from each other along a longitudinal direction of the cylindrical rod. The first and second ringshaped resonators are capable of being coupled to each other by way an evanescent field formed in an interior of the cylindrical rod portion.
Li, Quanshui; Hu, Jianling; Wang, Ziya; Wang, Fengping; Bao, Yongjun
2014-07-01
The resonant, near-resonant, and off-resonant plasmon coupling effects for the bonding modes in asymmetric dimers are illustrated by two types of configuration, one formed by a gold nanoparticle and a TiO2-Ag core-shell nanoparticle and the other formed by two TiO2-Ag core-shell nanoparticles with suitable sizes. The redshift and blueshift behaviours of the coupled bonding modes with decreasing gap are found under longitudinal and transverse polarization of light for these dimers in the resonant situation, respectively. Under the near-resonant situation, the redshift behaviours of the coupled bonding modes still remain under longitudinal polarization, whereas the two separated modes of monomers after coupling under transverse polarization exhibit no obvious peak-shift behaviours, and the one on the lower frequency side shows an apparent attenuation in the strength. Under the off-resonant situation, the redshift behaviours not only occur in the coupled modes under longitudinal polarization, but also occur in two separated modes under transverse polarization.
Zhang, Yundong; Zhang, Xuenan; Wang, Ying; Zhu, Ruidong; Gai, Yulong; Liu, Xiaoqi; Yuan, Ping
2013-04-08
We theoretically propose and experimentally perform a novel dispersion tuning scheme to realize a tunable Fano resonance in a coupled-resonator-induced transparency (CRIT) structure coupled Mach-Zehnder interferometer. We reveal that the profile of the Fano resonance in the resonator coupled Mach-Zehnder interferometers (RCMZI) is determined not only by the phase shift difference between the two arms of the RCMZI but also by the dispersion (group delay) of the CRIT structure. Furthermore, it is theoretically predicted and experimentally demonstrated that the slope and the asymmetry parameter (q) describing the Fano resonance spectral line shape of the RCMZI experience a sign reversal when the dispersion of the CRIT structure is tuned from abnormal dispersion (fast light) to normal dispersion (slow light). These theoretical and experimental results indicate that the reversible Fano resonance which holds significant implications for some attractive device applications such as highly sensitive biochemical sensors, ultrafast optical switches and routers can be realized by the dispersion tuning scheme in the RCMZI.
Electromagnetic coupling in a planar periodic configuration of resonators
C. Jouvaud
2012-12-01
Full Text Available We are studying arrays composed of a periodic arrangement of sub-wavelength resonators. An analytical model is developed inside an array of 4 by 4 multi-gap split ring resonators. To describe the frequency splitting of the single fundamental resonance, we propose a simple model based on the approximation of each resonator as an electrical dipole and a magnetic dipole that are driven by the same complex amplitude. We show that the relative strength of the two dipoles strongly depends on cell symmetry. With this approximation, the dispersion relation can be obtained for an infinite size array. A simple matrix diagonalization provides a powerful way to deduce the resonant frequencies for finite size array. These results are comforted by numerical simulations. Finally, an experimental demonstration of a tunable antenna based on this study is presented.
Howard, Anna K. T.
1999-01-01
The tiltrotor offers the best mix of hovering and cruise flight of any of the current V/STOL configurations. One possible improvement on the tiltrotors of today designs would be using a soft-inplane hingeless hub. The advantages to a soft-inplane hingeless hub range from reduced weight and maintenance to reduced vibration and loads. However, soft-inplane rotor systems are inherently in danger of the aeromechanical instabilities of ground and air resonance. Furthermore tiltrotors can be subject to whirl flutter. At least in part because of the potential for air and ground resonance in a soft-inplane rotor, the Bell XV-15, the Bell-Boeing V-22 Osprey, and the new Bell Augusta 609 have stiff-inplane, gimballed rotors which do not experience these instabilities. In order to design soft-inplane V/STOL aircraft that do not experience ground or air resonance, it is important to be able to predict these instabilities accurately. Much of the research studying the stability of tiltrotors has been focused on the understanding and prediction of whirl flutter. As this instability is increasingly well understood, air and ground resonance for a tiltrotor need to be investigated. Once we understand the problems of air and ground resonance in a tiltrotor, we must look for solutions to these instabilities. Other researchers have found composite or kinematic couplings in the blades of a helicopter helpful for ground and air resonance stability. Tiltrotor research has shown composite couplings in the wing to be helpful for whirl flutter. Therefore, this project will undertake to model ground and air resonance of a soft-inplane hingeless tiltrotor to understand the mechanisms involved and to evaluate whether aeroelastic couplings in the wing or kinematic couplings in the blades would aid in stabilizing these instabilities in a tiltrotor.
Piezoelectric resonators with mechanical damping and resistance in current conduction
Yook-Kong; YONG; Mihir; S; PATEL
2007-01-01
A novel design method for high Q piezoelectric resonators was presented and proposed using the 3-D equations of linear piezoelectricity with quasi-electrostatic approximation which include losses attributed to mechanical damping in solid and resistance in current conduction. There is currently no finite element software for estimating the Q of a resonator without apriori assumptions of the resonator impedance or damping. There is a necessity for better and more realistic modeling of resonators and filters due to miniaturization and the rapid advances in frequency ranges in telecommunication.We presented new three-dimensional finite element models of quartz and barium titanate resonators with mechanical damping and resistance in current conduction. Lee, Liu and Ballato's 3-D equations of linear piezoelectricity with quasi-electro- static approximation which include losses attributed to mechanical damping in solid and resistance in current conduction were formulated in a weak form and implemented in COMSOL. The resulting finite element model could predict the Q and other electrical parameters for any piezoelectric resonator without apriori assumptions of damping or resistance. Forced and free vibration analyses were performed and the results for the Q and other electrical parameters were obtained. Comparisons of the Q and other electrical parameters obtained from the free vibration analysis with their corresponding values from the forced vibration analysis were found to be in excellent agreement. Hence, the frequency spectra obtained from the free vibration analysis could be used for designing high Q resonators. Results for quartz thickness shear AT-cut and SC-cut resonators and thickness stretch poled barium titanate resonators were presented. An unexpected benefit of the model was the prediction of resonator Q with energy losses via the mounting supports.
Intrinsic resonance representation of quantum mechanics
Carioli, M.; Heller, E.J.; Møller, Klaus Braagaard
1997-01-01
an optimal representation, based purely on classical mechanics. ''Hidden'' constants of the motion and good actions already known to the classical mechanics are thus incorporated into the basis, leaving the quantum effects to be isolated and included by small matrix diagonalizations. This simplifies...
Far-off-resonant coupling between a semiconductor quantum dot and an optical cavity
Lund, Anders Mølbjerg; Settnes, Mikkel; Nielsen, Per Kær
2014-01-01
We present an investigation of the far-off-resonant coupling between a semiconductor quantum dot and a cavity. We show that the enhanced coupling observed in experiments is explained by Coulomb interactions with wetting layer carriers. © 2014 Optical Society of America.......We present an investigation of the far-off-resonant coupling between a semiconductor quantum dot and a cavity. We show that the enhanced coupling observed in experiments is explained by Coulomb interactions with wetting layer carriers. © 2014 Optical Society of America....
Vertically Coupled Microring Resonator Filter :Versatile Building Block for VLSI Filter Circuits
Yasuo; Kokubun
2003-01-01
In this review, the recent progress in the development of vertically coupled micro-ring resonator filters is summarized and the potential applications of the filters leading to the development of VLSI photonics are described.
Vertically Coupled Microring Resonator Filter : Versatile Building Block for VLSI Filter Circuits
Yasuo Kokubun
2003-01-01
In this review, the recent progress in the development of vertically coupled micro-ring resonator filters is summarized and the potential applications of the filters leading to the development of VLSI photonics are described.
Mode coupling in terahertz metamaterials using sub-radiative and super-radiative resonators
Qiao, Shen; Zhang, Yaxin, E-mail: Zhangyaxin@uestc.edu.cn; Zhao, Yuncheng; Xu, Gaiqi; Sun, Han; Yang, Ziqiang [Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054 (China); Liang, Shixiong [National Key Laboratory of Application Specific Integrated Circuit, Hebei Semiconductor Research Institute, Shijiazhuang 050051 (China)
2015-11-21
We theoretically and experimentally explored the electromagnetically induced transparency (EIT) mode-coupling in terahertz (THz) metamaterial resonators, in which a dipole resonator with a super-radiative mode is coupled to an inductance-capacitance resonator with a sub-radiative mode. The interference between these two resonators depends on the relative spacing between them, resulting in a tunable transparency window in the absorption spectrum. Mode coupling was experimentally demonstrated for three spacing dependent EIT metamaterials. Transmittance of the transparency windows could be either enhanced or suppressed, producing different spectral linewidths. These spacing dependent mode-coupling metamaterials provide alternative ways to create THz devices, such as filters, absorbers, modulators, sensors, and slow-light devices.
Coupled-resonator optical waveguides: Q-factor and disorder influence
Grgic, Jure; Campaioli, Enrico; Raza, Søren;
2011-01-01
Coupled resonator optical waveguides (CROW) can significantly reduce light propagation pulse velocity due to pronounced dispersion properties. A number of interesting applications have been proposed to benefit from such slow-light propagation. Unfortunately, the inevitable presence of disorder, i...
Localized surface plasmons selectively coupled to resonant light in tubular microcavities
Yin, Yin; Böttner, Stefan; Yuan, Feifei; Giudicatti, Silvia; Naz, Ehsan Saei Ghareh; Ma, Libo; Schmidt, Oliver G
2016-01-01
Vertical gold-nanogaps are created on microtubular cavities to explore the coupling between resonant light supported by the microcavities and surface plasmons localized at the nanogaps. Selective coupling of optical axial modes and localized surface plasmons critically depends on the exact location of the gold-nanogap on the microcavities which is conveniently achieved by rolling-up specially designed thin dielectric films into three dimensional microtube ring resonators. The coupling phenomenon is explained by a modified quasi-potential model based on perturbation theory. Our work reveals the coupling of surface plasmon resonances localized at the nanoscale to optical resonances confined in microtubular cavities at the microscale, implying a promising strategy for the investigation of light-matter interactions.
9.4 nm Tunable Vertically Coupled Microring Resonator Filter by Thermo-Optic Effect
Yuji; Yanagase; Shunichi; Yamagata; Yasuo; Kokubun
2003-01-01
A wide range (9.4nm) tuning of vertically coupled microring resonator filter was demonstrated utilizing a large TO coefficient of polymer. The power consumption was about 60m W and no degradation of filter response was observed.
9.4 nm Tunable Vertically Coupled Microring Resonator Filter by Thermo-Optic Effect
Yuji Yanagase; Shunichi Yamagata; Yasuo Kokubun
2003-01-01
A wide range (9.4nm) tuning of vertically coupled microring resonator filter was demonstrated utilizing a large TO coefficient of polymer. The power consumption was about 60mW and no degradation of filter response was observed.
Linewidth broadening of a quantum dot coupled to an off-resonant cavity
Majumdar, Arka; Kim, Erik; Englund, Dirk; Kim, Hyochul; Petroff, Pierre; Vuckovic, Jelena
2010-01-01
We study the coupling between a photonic crystal cavity and an off-resonant quantum dot under resonant excitation of the cavity or the quantum dot. Linewidths of the quantum dot and the cavity as a function of the excitation laser power are measured. We show that the linewidth of the quantum dot, measured by observing the cavity emission, is significantly broadened compared to the theoretical estimate. This indicates additional incoherent coupling between the quantum dot and the cavity.
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.
Zhang, Jin; Cheng, Ying; Liu, Xiaojun
2017-06-01
The effective impedance modulation of artificial acoustic metamaterials is crucial in application scenarios. Here, a Mie-resonator dimer is proposed as a tunable mutual inductive coupled unit to drive a mismatched to matched impedance transition, which can achieve a wide impedance modulation range. We have demonstrated a widely tunable impedance modulation to realize an extraordinary acoustic transmission at low frequency by using the metasurface with a Mie-resonator dimer. Based on full-wave simulations, a two-port equivalent circuit model is made to explain the mechanism of the impedance modulation. Moreover, the proposal metasurface can be tuned to exhibit any desired transmittance.
Decoupling crossover in asymmetric broadside coupled split-ring resonators at terahertz frequencies
Keiser, G. R.; Strikwerda, Andrew; Fan, K.;
2013-01-01
We investigate the electromagnetic response of asymmetric broadside coupled split-ring resonators (ABC-SRRs) as a function of the relative in-plane displacement between the two component SRRs. The asymmetry is defined as the difference in the capacitive gap widths (Δg) between the two resonators ...
2012-06-29
thinned using a thinner to obtain one micron thick films. The dye doped films were later patterned using either EBL or photolithography. Scanning...established for the microdisk resonators. Scanning electron microscope images of single and coupled microring resonators fabricated using EBL are shown
Laser and cavity cooling of a mechanical resonator with a nitrogen-vacancy center in diamond
Giannelli, Luigi; Betzholz, Ralf; Kreiner, Laura; Bienert, Marc; Morigi, Giovanna
2016-11-01
We theoretically analyze the cooling dynamics of a high-Q mode of a mechanical resonator, when the structure is also an optical cavity and is coupled with a nitrogen-vacancy (NV) center. The NV center is driven by a laser and interacts with the cavity photon field and with the strain field of the mechanical oscillator, while radiation pressure couples the mechanical resonator and cavity field. Starting from the full master equation we derive the rate equation for the mechanical resonator's motion, whose coefficients depend on the system parameters and on the noise sources. We then determine the cooling regime, the cooling rate, the asymptotic temperatures, and the spectrum of resonance fluorescence for experimentally relevant parameter regimes. For these parameters, we consider an electronic transition, whose linewidth allows one to perform sideband cooling, and show that the addition of an optical cavity in general does not improve the cooling efficiency. We further show that pure dephasing of the NV center's electronic transitions can lead to an improvement of the cooling efficiency.
Resonant Absorption Mechanical Spectrometer and Its Applications in Solids
张进修; 龚康; 熊小敏; 丁喜冬
2003-01-01
An improved apparatus is developed from Ke-pendulum. This new apparatus, resonant absorption mechanical spectrometer (RAMS), can measure the internal friction of solids under a forced vibration mode and the measuring frequency can change quasi-continually from a frequency that is much lower than the resonant frequency of the pendulum system, fr, tothe one that is much higher than fr. The internal friction measurement is able to cover the frequency range from 10-3 Hz to kHz. The measurement method and the calculation formula of the internal friction measured by a RAMS in the full frequency range are derived. A series of resonant absorption peaks are observed in copper, aluminium, zinc, iron samples by the RAMS. The resonant absorption characteristics of the copper sample are studied in details. The experimental results indicate that the position (frequency) of the resonant absorption peaks are independent of the resonant frequency of the pendulum system. The reality of resonant absorption mechanical spectra is discussed and an inference based on the experimental results is presented such that the RAMS is able to characterize some feature of solid materials.
Macquarrie, E. R.; Otten, M.; Gray, S. K.; Fuchs, G. D.
2017-02-01
Cooling a mechanical resonator mode to a sub-thermal state has been a long-standing challenge in physics. This pursuit has recently found traction in the field of optomechanics in which a mechanical mode is coupled to an optical cavity. An alternate method is to couple the resonator to a well-controlled two-level system. Here we propose a protocol to dissipatively cool a room temperature mechanical resonator using a nitrogen-vacancy centre ensemble. The spin ensemble is coupled to the resonator through its orbitally-averaged excited state, which has a spin-strain interaction that has not been previously studied. We experimentally demonstrate that the spin-strain coupling in the excited state is 13.5+/-0.5 times stronger than the ground state spin-strain coupling. We then theoretically show that this interaction, combined with a high-density spin ensemble, enables the cooling of a mechanical resonator from room temperature to a fraction of its thermal phonon occupancy.
Optimized ground coupled heat pump mechanical package
Catan, M.A.
1987-01-01
This project addresses the question of how well a ground coupled heat pump system could perform with a heat pump which was designed specifically for such systems operating in a northern climate. Conventionally, systems are designed around water source heat pumps which are not designed for ground coupled heat pump application. The objective of the project is to minimize the life cycle cost for a ground coupled system given the freedom to design the heat pump and the ground coil in concert. In order to achieve this objective a number of modeling tools were developed which will likely be of interest in their own right.
Shi, L; Rekola, H T; Martikainen, J -P; Moerland, R J; Törmä, P
2014-01-01
We study spatial coherence properties of a system composed of periodic silver nanoparticle arrays covered with a fluorescent organic molecule (DiD) film. The evolution of spatial coherence of this composite structure from the weak to the strong coupling regime is investigated by systematically varying the coupling strength between the localized DiD excitons and the collective, delocalized modes of the nanoparticle array known as surface lattice resonances. A gradual evolution of coherence from the weak to the strong coupling regime is observed, with the strong coupling features clearly visible in interference fringes. A high degree of spatial coherence is demonstrated in the strong coupling regime, even when the mode is very excitonlike (80%), in contrast to the purely localized nature of molecular excitons. We show that coherence appears in proportion to the weight of the plasmonic component of the mode throughout the weak-to-strong coupling crossover, providing evidence for the hybrid nature of the normal m...
LANG Jia-Hong
2011-01-01
Single photon transport properties in a one-dimensional array of coupled microcavities waveguide coupled to a whispering-gallery resonator interacting with a A-type system are theoretically investigated.The calculations reveal that the transport properties of single photons with arbitrary energy can be controlled by varying the Rabi frequency and detuning the control optical field.This phenomenon can be used for controllable optical switching.Single photon transport properties in a onedimensional waveguide coupled to a two-level[1-10] or multi-level[11-17] system have been studied theoretically and experimentally for their potential applications in quantum information and all-optical devices.A coupled cavity array is considered as a one-dimensional waveguide and the single photon transport properties in such a system coupled to a two-level and multi-level system have been studied.%Single photon transport properties in a one-dimensional array of coupled microcavities waveguide coupled to a whispering-gallery resonator interacting with a A-type system are theoretically investigated. The calculations reveal that the transport properties of single photons with arbitrary energy can be controlled by varying the Rabi frequency and detuning the control optical field. This phenomenon can be used for controllable optical switching.
Coupled diffusion and mechanics in battery electrodes
Eshghinejad, Ahmadreza
We are living in a world with continuous production and consumption of energy. The energy production in the past decades has started to move away from petrochemical sources toward sustainable sources such as solar, wind and geothermal. Also, the energy consumption is further adapting to the sustainable sources. For instance, in recent years electric vehicles are growing fast that can consume sustainable electric energy stored in their batteries. In this direction, in order to further move toward sustainable energy, materials are becoming increasingly important for storing electric energy. Although, currently the technologies such as Li-ion batteries and solid-oxide fuel cells are commercially available for energy applications, improvements are crucial for the next generation of many other technologies producing or consuming sustainable energies. A critical aspect of the electrochemical activities involved in energy storage technologies such as Li-ion batteries and solid-oxide fuel cells is the diffusion of ions into the electrode materials. This process ultimately governs various functional properties of the batteries such as capacity and charging/discharging rates. The first goal of this dissertation is to develop mathematical tools to analyze the ionic diffusion and investigate its coupling with mechanics in electrodes. For this purpose, a thermodynamics-based modeling framework is developed and numerically solved using two numerical methods to analyze ionic diffusion in heterogeneous and structured electrodes. The next goal of this dissertation is to develop and analyze characterization techniques to probe the electrochemical processes at the nano-scale. To this end, the mathematical models are first employed to model a previously developed Atomic Force Microscopy based technique to probe local electrochemical activities called Electrochemical Strain Microscopy (ESM). This method probes the activities by inducing AC electric field to perturb ionic activities and
Enhanced four-wave mixing via photonic bandgap coupled defect resonances.
Blair, S
2005-05-16
Frequency conversion efficiency via four-wave mixing in coupled 1-D photonic crystal defect structures is studied numerically. In structures where all interacting frequencies coincide with intraband defect resonances, energy conversion efficiencies greater than 5% are predicted. Because the frequency spacings are determined by the free-spectral range, thereby requiring long defects for small spacings using intraband resonances, four-wave mixing using coupled-defect miniband resonances in more compact structures is also studied. Conversion efficiencies of greater than 1% are obtained in this case.
Inter-Well Coupling and Resonant Tunneling Modes of Multiple Graphene Quantum Wells
安丽萍; 王同标; 刘念华
2011-01-01
We investigate the inter-well coupling of multiple graphene quantum well structures consisting of graphene superlattices with different periodic potentials. The general form of the eigenlevel equation for the bound states of the quantum well is expressed in terms of the transfer matrix elements. It is found that the electronic transmission exhibits resonant tunneling peaks at the eigenlevels of the bound states and shifts to the higher energy with increasing the incident angle. If there are N coupled quantum wells, the resonant modes have N-fold splitting. The peaks of resonant tunneling can be controlled by modulating the graphene barriers.
Franco, A. F.; Landeros, P.
2016-09-01
We present a general model for the coupled magnetic resonances of an exchange interacting multilayer system, which can be implemented without complex analytical calculations or numerical simulations. The model allows one to study the spin wave modes of a multilayer structure with any number of layers, accounting for individual uniaxial and cubic anisotropies, and (static and dynamic) demagnetizing and external fields as well, assuming that only the interlayer exchange coupling mechanism is relevant between such magnetic layers. This scheme is applied to recent measurements of a NiFe/CoFe bilayer, and to studying the influence of the strength of ferromagnetic and antiferromagnetic exchange interactions and the applied field orientation on the spin wave modes and intensities of the ferromagnetic resonance response. We find that the acoustic oscillation mode tends to stabilize in frequency if the magnetizations of the layers are parallel to each other, while the optical mode stabilizes when the magnetizations are antiparallel. Furthermore, we find that each oscillation mode is governed by either the NiFe or the CoFe. The modes swap the governing layer as the perpendicular field increases, inducing a gap between their frequencies, which appears to be proportional to the exchange coupling. Finally, we find that the field linewidth of the bilayer due to Gilbert damping has a dependence on the frequency very similar to the linear dependence of the linewidth in single layers. The theoretical scheme presented here can be further used to explore magnetization dynamics in different multilayer architectures—such as exchange springs, structures with perpendicular magnetic anisotropy, and complex compositions of layer stacks—and can be useful as a basis to study multilayers with chiral and dipolar interactions.
Parametric resonance of intrinsic localized modes in coupled cantilever arrays
Kimura, Masayuki; Matsushita, Yasuo; Hikihara, Takashi
2016-08-01
In this study, the parametric resonances of pinned intrinsic localized modes (ILMs) were investigated by computing the unstable regions in parameter space consisting of parametric excitation amplitude and frequency. In the unstable regions, the pinned ILMs were observed to lose stability and begin to fluctuate. A nonlinear Klein-Gordon, Fermi-Pasta-Ulam-like, and mixed lattices were investigated. The pinned ILMs, particularly in the mixed lattice, were destabilized by parametric resonances, which were determined by comparing the shapes of the unstable regions with those in the Mathieu differential equation. In addition, traveling ILMs could be generated by parametric excitation.
Self-induced steps in a small Josephson junction strongly coupled to a multimode resonator
Larsen, A.; Jensen, H. Dalsgaard; Mygind, Jesper
1991-01-01
of the coupling parameter. The current steps are due to subharmonic parametric excitation of the fundamental mode of the resonator loaded by the junction admittance. Using an applied magnetic field to vary the coupling parameter, we traced out half-integer steps as well as the mode steps known from more weakly...
Modeling of mode-locked coupled-resonator optical waveguide lasers
Agger, Christian; Skovgård, Troels Suhr; Gregersen, Niels;
2010-01-01
Coupled-resonator optical waveguides made from coupled high-Q photonic crystal nanocavities are investigated for use as cavities in mode-locked lasers. Such devices show great potential in slowing down light and can serve to reduce the cavity length of a mode-locked laser. An explicit expression...
Near-field coupling and resonant cavity modes in plasmonic nanorod metamaterials.
Song, Haojie; Zhang, Junxi; Fei, Guangtao; Wang, Junfeng; Jiang, Kang; Wang, Pei; Lu, Yonghua; Iorsh, Ivan; Xu, Wei; Jia, Junhui; Zhang, Lide; Kivshar, Yuri S; Zhang, Lin
2016-10-14
Plasmonic resonant cavities are capable of confining light at the nanoscale, resulting in both enhanced local electromagnetic fields and lower mode volumes. However, conventional plasmonic resonant cavities possess large Ohmic losses at metal-dielectric interfaces. Plasmonic near-field coupling plays a key role in a design of photonic components based on the resonant cavities because of the possibility to reduce losses. Here, we study the plasmonic near-field coupling in the silver nanorod metamaterials treated as resonant nanostructured optical cavities. Reflectance measurements reveal the existence of multiple resonance modes of the nanorod metamaterials, which is consistent with our theoretical analysis. Furthermore, our numerical simulations show that the electric field at the longitudinal resonances forms standing waves in the nanocavities due to the near-field coupling between the adjacent nanorods, and a new hybrid mode emerges due to a coupling between nanorods and a gold-film substrate. We demonstrate that this coupling can be controlled by changing the gap between the silver nanorod array and gold substrate.
Near-field coupling and resonant cavity modes in plasmonic nanorod metamaterials
Song, Haojie; Zhang, Junxi; Fei, Guangtao; Wang, Junfeng; Jiang, Kang; Wang, Pei; Lu, Yonghua; Iorsh, Ivan; Xu, Wei; Jia, Junhui; Zhang, Lide; Kivshar, Yuri S.; Zhang, Lin
2016-10-01
Plasmonic resonant cavities are capable of confining light at the nanoscale, resulting in both enhanced local electromagnetic fields and lower mode volumes. However, conventional plasmonic resonant cavities possess large Ohmic losses at metal-dielectric interfaces. Plasmonic near-field coupling plays a key role in a design of photonic components based on the resonant cavities because of the possibility to reduce losses. Here, we study the plasmonic near-field coupling in the silver nanorod metamaterials treated as resonant nanostructured optical cavities. Reflectance measurements reveal the existence of multiple resonance modes of the nanorod metamaterials, which is consistent with our theoretical analysis. Furthermore, our numerical simulations show that the electric field at the longitudinal resonances forms standing waves in the nanocavities due to the near-field coupling between the adjacent nanorods, and a new hybrid mode emerges due to a coupling between nanorods and a gold-film substrate. We demonstrate that this coupling can be controlled by changing the gap between the silver nanorod array and gold substrate.
Quantum mechanical coherence, resonance, and mind
Stapp, H.P.
1995-03-26
Norbert Wiener and J.B.S. Haldane suggested during the early thirties that the profound changes in our conception of matter entailed by quantum theory opens the way for our thoughts, and other experiential or mind-like qualities, to play a role in nature that is causally interactive and effective, rather than purely epiphenomenal, as required by classical mechanics. The mathematical basis of this suggestion is described here, and it is then shown how, by giving mind this efficacious role in natural process, the classical character of our perceptions of the quantum universe can be seen to be a consequence of evolutionary pressures for the survival of the species.
Quantum mechanical coherence, resonance, and mind
Stapp, Henry P
1995-01-01
Norbert Wiener and J.B.S. Haldane suggested during the early thirties that the profound changes in our conception of matter entailed by quantum theory opens the way for our thoughts, and other experiential or mind-like qualities, to play a role in nature that is causally interactive and effective, rather than purely epiphenomenal, as required by classical mechanics. The mathematical basis of this suggestion is described here, and it is then shown how, by giving mind this efficacious role in natural process, the classical character of our perceptions of the quantum universe can be seen to be a consequence of evolutionary pressures for the survival of the species.
Zanotto, Simone
2015-01-01
In this article we discuss a model describing key features concerning the lineshapes and the coherent absorption conditions in Fano-resonant dissipative coupled oscillators. The model treats on the same footing the weak and strong coupling regimes, and includes the critical coupling concept, which is of great relevance in numerous applications; in addition, the role of asymmetry is thoroughly analyzed. Due to the wide generality of the model, which can be adapted to various frameworks like nanophotonics, plasmonics, and optomechanics, we envisage that the analytical formulas presented here will be crucial to effectively design devices and to interpret experimental results.
Coronal heating by resonant absorption: The effects of chromospheric coupling
Belien, A. J. C.; Martens, P. C. H.; Keppens, R.
1999-01-01
We present the first 2.5 dimensional numerical model calculations of the nonlinear wave dynamics and heating by resonant absorption in coronal loops with thermal structuring of the transition region and higher chromosphere. The numerical calculations were done with the Versatile Advection Code. The
Electron Transport Through a Quantum Wire with a Side-Coupled Quantum Dot:Fano Resonance
熊永建; 贺舟波
2004-01-01
The Fano resonance of a quantum wire (QW) with a side-coupled quantum dot (QD) is investigated. The QD has multilevel and is in the Coulomb blockade regime. We show that there are two aspects in contribution to asymmetric Fano dip line shape of conductance: (1) the quantum interference between the resonant level and non-resonant levels, (2) the asymmetric electron occupation of levels in the two sides of a resonant level in the QD. The smearing of the asymmetry of the dip structure with the increasing temperature is partially attributed to fluctuation of electron state in the QD.
Vibrational resonance, allostery, and activation in rhodopsin-like G protein-coupled receptors
Woods, Kristina N.; Pfeffer, Jürgen; Dutta, Arpana; Klein-Seetharaman, Judith
2016-11-01
G protein-coupled receptors are a large family of membrane proteins activated by a variety of structurally diverse ligands making them highly adaptable signaling molecules. Despite recent advances in the structural biology of this protein family, the mechanism by which ligands induce allosteric changes in protein structure and dynamics for its signaling function remains a mystery. Here, we propose the use of terahertz spectroscopy combined with molecular dynamics simulation and protein evolutionary network modeling to address the mechanism of activation by directly probing the concerted fluctuations of retinal ligand and transmembrane helices in rhodopsin. This approach allows us to examine the role of conformational heterogeneity in the selection and stabilization of specific signaling pathways in the photo-activation of the receptor. We demonstrate that ligand-induced shifts in the conformational equilibrium prompt vibrational resonances in the protein structure that link the dynamics of conserved interactions with fluctuations of the active-state ligand. The connection of vibrational modes creates an allosteric association of coupled fluctuations that forms a coherent signaling pathway from the receptor ligand-binding pocket to the G-protein activation region. Our evolutionary analysis of rhodopsin-like GPCRs suggest that specific allosteric sites play a pivotal role in activating structural fluctuations that allosterically modulate functional signals.
Matsuno, Yuki; Sakurai, Atsushi
2017-02-01
The purpose of this study is to clarify the optical characteristics of a Tungsten-SiO2-based film-coupled metamaterial with a fishnet-shaped grating, and we aim to show that this structure could potentially be used as a solar selective absorber for a solar thermophotovoltaic system. The proposed film-coupled metamaterial absorber combined with a fishnet-shaped grating shows significant enhancement in its absorption in the visible spectral region compared with a flat Tungsten surface, and it keeps its spectral emission low in the infrared region, thereby reducing radiative heat loss. The underlying mechanisms of the proposed absorber are discussed through a 3D full-wave electromagnetic simulation, the results of which are compared with that of theoretical equations. Furthermore, its spectral absorption under oblique incident light at the transverse magnetic and transverse electric waves is scrutinized. The underlying absorption mechanisms and relations between each optical resonance are discussed in this paper and will prove to be fundamental not only in the design of solar selective absorbers but also in other wavelength-selective thermal radiation controlling devices.
Non-resonant instability of coupled Alfvén and drift compressional modes in magnetospheric plasma
Mager, Pavel N.; Klimushkin, Dmitri Yu
2017-09-01
A new mechanism of generation of the high-m compressional ULF waves in the magnetosphere is considered. It is suggested that the wave can be generated by the non-resonant instability of coupled Alfvén and drift compressional modes in the energetic component of the magnetospheric plasma. A stability analysis of the of the coupled modes in the inhomogeneous finite-β plasma in the dipole-like field in gyrokinetics is performed. A quadratic equation was obtained that determines mode frequency and the growth rate. The frequencies of both modes depend on the azimuthal wave number, m. The branches are merged at some critical m value, forming a mode with both real and imaginary parts of the wave frequency. This mode is amplified due to the instability called the drift coupling instability. The instability criterion was found. Its growth rate is determined by the mode coupling.
CHENG Mu-Tian; SONG Yan-Yan; LUO Ya-Qin; ZHAO Guang-xing
2011-01-01
We investigate theoretically the single-photon scattering by a A-type three-level system interacting with a whispering-gallery-type resonator which is coupled to a one-dimensional waveguide by full quantum-mechanical approach,The single-photon transmission amplitude and reflection amplitude are obtained exactly via real-space approach. The single-photon transport properties controlling by classic optical field are discussed. The critical coupling condition in the coupled waveguide-whispering-gallery resonator-atom with three-level system is also analyzed.
Physico-chemo-mechanical coupling mechanisms in soil behavior
Hu, Liangbo
Many processes in geomechanics or geotechnical/geomechanical system engineering involve phenomena that are physical and/or chemical in nature, the understanding of which is crucial to modeling the mechanical responses of soils to various loads. Such physico-chemo-mechanical coupling mechanisms are prevalent in two different types of geomechanical processes studied in this dissertation: long-term soil/sediments compaction & desiccation cracking. Most commonly the underlying physical and chemical phenomena are explained, formulated and quantified at microscopic level. In addition to the necessity of capturing the coupling mechanisms, another common thread that emerges in formulating their respective mathematical model is the necessity of linking phenomena occurring at different scales with a theory to be formulated at a macroscopic continuum level. Part I of this dissertation is focused on the subject of long-term compaction behavior of soils and sediments. The interest in this subject arises from the need to evaluate reservoir compaction and land subsidence that may result from oil/gas extraction in petroleum engineering. First, a damage-enhanced reactive chemo-plasticity model is developed to simulate creep of saturated geomaterials, a long-term strain developed at constant stress. Both open and closed systems are studied. The deformation at a constant load in a closed system exhibits most of the characteristics of the classical creep. Primary, secondary and tertiary creep can be interpreted in terms of dominant mechanisms in each phase, emphasizing the role of the rates of dissolution and precipitation, variable reaction areas and chemical softening intensity. The rest of Part I is devoted to the study of soil aging, an effect of a localized mineral dissolution related creep strain and subsequent material stiffening. A three-scale mathematical model is developed to numerically simulate the scenarios proposed based on macroscopic experiments and geochemical
Nayak, R. K.; Das, S.; Panda, A. K.; Sahu, T., E-mail: tsahu-bu@rediffmail.com [Department of Electronics and Communication Engineering, National Institute of Science and Technology, Palur Hills, Berhampur-761 008, Odisha (India)
2015-11-15
We show that sharp nonmonotic variation of low temperature electron mobility μ can be achieved in GaAs/Al{sub x}Ga{sub 1-x}As barrier delta-doped double quantum well structure due to quantum mechanical transfer of subband electron wave functions within the wells. We vary the potential profile of the coupled structure as a function of the doping concentration in order to bring the subbands into resonance such that the subband energy levels anticross and the eigen states of the coupled structure equally share both the wells thereby giving rise to a dip in mobility. When the wells are of equal widths, the dip in mobility occurs under symmetric doping of the side barriers. In case of unequal well widths, the resonance can be obtained by suitable asymmetric variation of the doping concentrations. The dip in mobility becomes sharp and also the wavy nature of mobility takes a rectangular shape by increasing the barrier width. We show that the dip in mobility at resonance is governed by the interface roughness scattering through step like changes in the subband mobilities. It is also gratifying to show that the drop in mobility at the onset of occupation of second subband is substantially supressed through the quantum mechanical transfer of subband wave functions between the wells. Our results can be utilized for performance enhancement of coupled quantum well devices.
A Quantum Mechanical Review of Magnetic Resonance Imaging
Odaibo, Stephen G
2012-01-01
In this paper, we review the quantum mechanics of magnetic resonance imaging (MRI). We traverse its hierarchy of scales from the spin and orbital angular momentum of subatomic particles to the ensemble magnetization of tissue. And we review a number of modalities used in the assessment of acute ischemic stroke and traumatic brain injury.
Shapiro and parametric resonances in coupled Josephson junctions
Gaafar, Ma A.; Shukrinov, Yu M.; Foda, A.
2012-11-01
The effect of microwave irradiation on the phase dynamics of intrinsic Josephson junctions in high temperature superconductors is investigated. We compare the current-voltage characteristics for a stack of coupled Josephson junctions under external irradiation calculated in the framework of CCJJ and CCJJ+DC models.
Nuclear magnetic resonance J coupling constant polarizabilities of hydrogen peroxide
Kjær, Hanna; Nielsen, Monia R.; Pagola, Gabriel I.
2012-01-01
approximation for the small molecule hydrogen peroxide, which allowed us to carry out calculations with the largest available basis sets optimized for the calculation of NMR coupling constants. We ¿nd a systematic but rather slow convergence with the one-electron basis set and that augmentation functions...
Adato, Ronen; Artar, Alp; Erramilli, Shyamsunder; Altug, Hatice
2013-06-12
Coupled plasmonic resonators have become the subject of significant research interest in recent years as they provide a route to dramatically enhanced light-matter interactions. Often, the design of these coupled mode systems draws intuition and inspiration from analogies to atomic and molecular physics systems. In particular, they have been shown to mimic quantum interference effects, such as electromagnetically induced transparency (EIT) and Fano resonances. This analogy also been used to describe the surface-enhanced absorption effect where a plasmonic resonance is coupled to a weak molecular resonance. These important phenomena are typically described using simple driven harmonic (or linear) oscillators (i.e., mass-on-a-spring) coupled to each other. In this work, we demonstrate the importance of an essential interdependence between the rate at which the system can be driven by an external field and its damping rate through radiative loss. This link is required in systems exhibiting time-reversal symmetry and energy conservation. Not only does it ensure an accurate and physically consistent description of resonant systems but leads directly to interesting new effects. Significantly, we demonstrate this dependence to predict a transition between EIT and electromagnetically induced absorption that is solely a function of the ratio of the radiative to intrinsic loss rates in coupled resonator systems. Leveraging the temporal coupled mode theory, we introduce a unique and intuitive picture that accurately describes these effects in coupled plasmonic/molecular and fully plasmonic systems. We demonstrate our approach's key features and advantages analytically as well as experimentally through surface-enhanced absorption spectroscopy and plasmonic metamaterial applications.
Koya, Alemayehu Nana; Ji, Boyu; Hao, Zuoqiang; Lin, Jingquan, E-mail: linjingquan@cust.edu.cn [School of Science, Changchun University of Science and Technology, Changchun 130022 (China)
2015-09-21
Combined effects of polarization, split gap, and rod width on the resonance hybridization and near field properties of strongly coupled gold dimer-rod nanosystem are comparatively investigated in the light of the constituent nanostructures. By aligning polarization of the incident light parallel to the long axis of the nanorod, introducing small split gaps to the dimer walls, and varying width of the nanorod, we have simultaneously achieved resonance mode coupling, huge near field enhancement, and prolonged plasmon lifetime. As a result of strong coupling between the nanostructures and due to an intense confinement of near fields at the split and dimer-rod gaps, the extinction spectrum of the coupled nanosystem shows an increase in intensity and blueshift in wavelength. Consequently, the near field lifespan of the split-nanosystem is prolonged in contrast to the constituent nanostructures and unsplit-nanosystem. On the other hand, for polarization of the light perpendicular to the long axis of the nanorod, the effect of split gap on the optical responses of the coupled nanosystem is found to be insignificant compared to the parallel polarization. These findings and such geometries suggest that coupling an array of metallic split-ring dimer with long nanorod can resolve the huge radiative loss problem of plasmonic waveguide. In addition, the Fano-like resonances and immense near field enhancements at the split and dimer-rod gaps imply the potentials of the nanosystem for practical applications in localized surface plasmon resonance spectroscopy and sensing.
Manifestation of resonance-related chaos in coupled Josephson junctions
Shukrinov, Yu.M. [BLTP, JINR, Dubna, Moscow Region, 141980 (Russian Federation); Hamdipour, M. [BLTP, JINR, Dubna, Moscow Region, 141980 (Russian Federation); Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Zanjan (Iran, Islamic Republic of); Kolahchi, M.R. [Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Zanjan (Iran, Islamic Republic of); Botha, A.E., E-mail: bothaae@unisa.ac.za [Department of Physics, University of South Africa, P.O. Box 392, Pretoria 0003 (South Africa); Suzuki, M. [Photonics and Electronics Science and Engineering Center and Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510 (Japan)
2012-11-01
Manifestation of chaos in the temporal dependence of the electric charge is demonstrated through the calculation of the maximal Lyapunov exponent, phase–charge and charge–charge Lissajous diagrams and correlation functions. It is found that the number of junctions in the stack strongly influences the fine structure in the current–voltage characteristics and a strong proximity effect results from the nonperiodic boundary conditions. The observed resonance-related chaos exhibits intermittency. The criteria for a breakpoint region with no chaos are obtained. Such criteria could clarify recent experimental observations of variations in the power output from intrinsic Josephson junctions in high temperature superconductors.
Manifestation of resonance-related chaos in coupled Josephson junctions
Shukrinov, Yu. M.; Hamdipour, M.; Kolahchi, M. R.; Botha, A. E.; Suzuki, M.
2012-11-01
Manifestation of chaos in the temporal dependence of the electric charge is demonstrated through the calculation of the maximal Lyapunov exponent, phase-charge and charge-charge Lissajous diagrams and correlation functions. It is found that the number of junctions in the stack strongly influences the fine structure in the current-voltage characteristics and a strong proximity effect results from the nonperiodic boundary conditions. The observed resonance-related chaos exhibits intermittency. The criteria for a breakpoint region with no chaos are obtained. Such criteria could clarify recent experimental observations of variations in the power output from intrinsic Josephson junctions in high temperature superconductors.
Resonance-enhanced waveguide-coupled silicon-germanium detector
Alloatti, Luca
2016-01-01
A photodiode with 0.55$\\pm$0.1 A/W responsivity at a wavelength of 1176.9 nm has been fabricated in a 45 nm microelectronics silicon-on-insulator foundry process. The resonant waveguide photodetector exploits carrier generation in silicon-germanium (SiGe) within a microring which is compatible with high-performance electronics. A 3 dB bandwidth of 5 GHz at -4 V bias is obtained with a dark current of less than 20 pA.
Optical cavity coupled surface plasmon resonance sensing for enhanced sensitivity
Zheng Zheng; Xin Zhao; Jinsong Zhu; Jim Diamond
2008-01-01
A surface plasmon resonance (SPR) sensing system based on the optical cavity enhanced detection tech-nique is experimentally demonstrated. A fiber-optic laser cavity is built with a SPR sensor inside. By measuring the laser output power when the cavity is biased near the threshold point, the sensitivity, defined as the dependence of the output optical intensity on the sample variations, can be increased by about one order of magnitude compared to that of the SPR sensor alone under the intensity interrogation scheme. This could facilitate ultra-high sensitivity SPR biosensing applications. Further system miniaturization is possible by using integrated optical components and waveguide SPR sensors.
Sadeqi, Soheil
The desire to reduce power consumption of current integrated circuits has led design engineers to focus on harvesting energy from free ambient sources such as vibrations. The energy harvested this way can eliminate the need for battery replacement, particularly, in low-energy remote sensing and wireless devices. Currently, most vibration-based energy harvesters are designed as linear resonators, therefore, they have a narrow resonance frequency. The optimal performance of such harvesters is achieved only when their resonance frequency is matched with the ambient excitation. In practice, however, a slight shift of the excitation frequency will cause a dramatic reduction in their performance. In the majority of cases, the ambient vibrations are totally random with their energy distributed over a wide frequency spectrum. Thus, developing techniques to extend the bandwidth of vibration-based energy harvesters has become an important field of research in energy harvesting systems. This thesis first reviews the broadband vibration-based energy harvesting techniques currently known in some detail with regard to their merits and applicability under different circumstances. After that, the design, fabrication, modeling and characterization of three new piezoelectric-based energy harvesting mechanism, built typically for rotary motion applications, is discussed. A step-by-step procedure is followed in order to broaden the bandwidth of such energy harvesters by introducing a coupled spring-mass system attached to a PZT beam undergoing rotary motion. It is shown that the new strategies can indeed give rise to a wide-band frequency response making it possible to fine-tune their dynamical response. The numerical results are shown to be in good agreement with the experimental data as far as the frequency response is concerned.
Electro-thermo-mechanical model for bulk acoustic wave resonators.
Rocas, Eduard; Collado, Carlos; Mateu, Jordi; Orloff, Nathan D; Aigner, Robert; Booth, James C
2013-11-01
We present the electro-thermo-mechanical constitutive relations, expanded up to the third order, for a BAW resonator. The relations obtained are implemented into a circuit model, which is validated with extensive linear and nonlinear measurements. The mathematical analysis, along with the modeling, allows us to identify the dominant terms, which are the material temperature derivatives and two intrinsic nonlinear terms, and explain, for the first time, all observable effects in a BAW resonator by use of a unified physical description. Moreover, the terms that are responsible for the second-harmonic generation and the frequency shift with dc voltage are shown to be the same.
Measurements of complex coupling coefficients in a ring resonator of a laser gyroscope
Bessonov, A. S.; Makeev, A. P.; Petrukhin, E. A.
2017-07-01
A method is proposed for measuring complex coupling coefficients in a ring optical resonator in the absence of an active gas mixture. A setup is described on which measurements are performed in ring resonators of ring He-Ne lasers with a wavelength of 632.8 nm. A model of backscattering field interference between conservative and dissipative sources is presented. Within the framework of this model, the unusual behaviour of backscattering fields in ring resonators observed in experiments is explained: a significant difference in the moduli of coupling coefficients of counterpropagating waves and variation of the magnitude of the total phase shift in a wide range. It is proposed to use this method as a metrological method when assembling and aligning a ring resonator of a laser gyroscope.
Gain enhanced Fano resonance in a coupled photonic crystal cavity-waveguide structure
Zhao, Yanhui; Qian, Chenjiang; Qiu, Kangsheng; Tang, Jing; Sun, Yue; Jin, Kuijuan; Xu, Xiulai
2016-01-01
Systems with coupled cavities and waveguides have been demonstrated as optical switches and optical sensors. To optimize the functionalities of these optical devices, Fano resonance with asymmetric and steep spectral line shape has been used. We theoretically propose a coupled photonic crystal cavity-waveguide structure to achieve Fano resonance by placing partially reflecting elements in waveguide. To enhance Fano resonance, optical gain material is introduced into the cavity. As the gain increases, the transmission line shape becomes steepened and the transmissivity can be six times enhanced, giving a large contrast by a small frequency shift. It is prospected that the gain enhanced Fano resonance is very useful for optical switches and optical sensors. PMID:27640809
Resonance width distribution in RMT: Weak-coupling regime beyond Porter-Thomas
Fyodorov, Yan V.; Savin, Dmitry V.
2015-05-01
We employ the random matrix theory (RMT) framework to revisit the distribution of resonance widths in quantum chaotic systems weakly coupled to the continuum via a finite number M of open channels. In contrast to the standard first-order perturbation theory treatment we do not a priori assume the resonance widths being small compared to the mean level spacing. We show that to the leading order in weak coupling the perturbative χ^2M distribution of the resonance widths (in particular, the Porter-Thomas distribution at M = 1) should be corrected by a factor related to a certain average of the ratio of square roots of the characteristic polynomial (“spectral determinant”) of the underlying RMT Hamiltonian. A simple single-channel expression is obtained that properly approximates the width distribution also at large resonance overlap, where the Porter-Thomas result is no longer applicable.
Advanced coupled-micro-resonator architectures for dispersion and spectral engineering applications
Van, Vien
2009-02-01
We report recent progress in the design and fabrication of coupled optical micro-resonators and their applications in realizing compact OEIC devices for optical spectral engineering. By leveraging synthesis techniques for analog and digital electrical circuits, advanced coupled-microring device architectures can be realized with the complexity and functionality approaching that of state-of-the-art microwave filters. In addition, the traveling wave nature of microring resonators can be exploited to realize novel devices not possible with standing wave resonators. Applications of coupledmicro- resonator devices in realizing complex optical transfer functions for amplitude, phase and group delay engineering will be presented. Progress in the practical implementation of these devices in the Silicon-on-Insulator OEIC platform will be highlighted along with the challenges and potential for constructing very high order optical filters using coupledmicroring architectures.
Improved Coupling to Plasmonic Slot Waveguide via a Resonant Nanoantenna
Andryieuski, Andrei; Zenin, Vladimir A.; Malureanu, Radu;
-limited optical waves into deep-subwavelength plasmonic waveguides. In this contribution we provide a systematic approach to design, fabricate and characterize an efficient, broadband, and compact dipole antenna nanocoupler for the telecom wavelength range around 1.55 µm. We consider the vertical coupling...... configuration with a realistic excitation directly from an optical fiber. The scattering-type scanning near-field optical microscope (s-SNOM) characterization allows us not only to make relative comparison of the efficiencies (in terms of the effective area) of different couplers, but also to measure......Plasmonic waveguides are considered as a future generation of optical interconnects in integrated circuits for datacom technologies due to their extreme field confinement performance. Inevitably, when using nanoscale waveguides, a new challenge emerges: how to effectively couple the diffraction...
Optical properties of surface plasmon resonances of coupled metallic nanorods.
Smythe, Elizabeth J; Cubukcu, Ertugrul; Capasso, Federico
2007-06-11
We present a systematic study of optical antenna arrays, in which the effects of coupling between the antennas, as well as of the antenna length, on the reflection spectra are investigated and compared. Such arrays can be fabricated on the facet of a fiber, and we propose a photonic device, a plasmonic optical antenna fiber probe, that can potentially be used for in-situ chemical and biological detection and surface-enhanced Raman scattering.
Resonance Coupling in Plasmonic Nanomatryoshka Homo- and Heterodimers
2016-08-16
breaking and conductive contact on the plasmon coupling in gold nanorod dimers,” ACS Nano 4, 4657-4666 (2010). 19 B. Luk’yanchuk, N. I. Zheludev, S. A...gold nanorods,” ACS Nano 5, 5976-5986 (2011). 21 Y, -I. Xu, “Electromagnetic scattering by an aggregate of spheres,” Appl. Opt. 34, 4573-4588 (1995). 22
Mechanics of couple-stress fluid coatings
Waxman, A. M.
1982-01-01
The formal development of a theory of viscoelastic surface fluids with bending resistance - their kinematics, dynamics, and rheology are discussed. It is relevant to the mechanics of fluid drops and jets coated by a thin layer of immiscible fluid with rather general rheology. This approach unifies the hydrodynamics of two-dimensional fluids with the mechanics of an elastic shell in the spirit of a Cosserat continuum. There are three distinct facets to the formulation of surface continuum mechanics. Outlined are the important ideas and results associated with each: the kinematics of evolving surface geometries, the conservation laws governing the mechanics of surface continua, and the rheological equations of state governing the surface stress and moment tensors.
YANG Xiao-Yan; XIE Wen-Chong; LIU De-Ming
2008-01-01
We investigate the sensitivity enhancement of surface plasmon resonance(SPR)sensors using planar metallic films closely coupled to nanogratings.The strong coupling between localized surface plasmon resonances(LSPRs)presenting in metallic nanostructures and surface plasmon polaritons(SPPs)propagating at the metallic film surface leads to changes of resonance reflection properties,resulting in enhanced sensitivity of SPR sensors.The effects of thickness of the metallic films,grating period and metal materials on the refractive index sensitivity of the device are investigated.The refractive index sensitivity of nanograting-based SPR sensors is predicted to be about 543 nm/RIU(refractive index unit)using optimized structure parameters.Our study on SPR sensors using planar metallic films closely coupled to nanogratings demonstrates the potential for significant improvement in refractive index sensitivity.
Szalai, Aniko; Somogyi, Aniko; Szenes, Andras; Banhelyi, Balazs; Csapo, Edit; Dekany, Imre; Csendes, Tibor; Csete, Maria
2016-01-01
Plasmonic biosensing chips were prepared by fabricating wavelength-scaled dielectric-metal interfacial gratings on thin polycarbonate films covered bimetal layers via two-beam interference laser lithography. Lysozyme (LYZ) biomolecules and gold nanoparticle (AuNP-LYZ) bioconjugates with 1:5 mass ratio were seeded onto the biochip surfaces. Surface plasmon resonance spectroscopy was performed before and after biomolecule seeding in a modified Kretschmann-arrangement by varying the azimuthal and polar angles to optimize the conditions for rotated grating-coupling. The shift of secondary and primary resonance peaks originating from rotated grating-coupling phenomenon was monitored to detect the biomolecule and bioconjugate adherence. Numerical calculations were performed to reproduce the measured reflectance spectra and the resonance peak shifts caused by different biocoverings. Comparison of measurements and calculations proved that monitoring the narrower secondary peaks under optimal rotated-grating coupling ...
Resonant enhanced parallel-T topology for weak coupling wireless power transfer pickup applications
Yao Guo
2015-07-01
Full Text Available For the wireless power transfer (WPT system, the transfer performance and the coupling coefficient are contradictory. In this paper, a novel parallel-T resonant topology consists of a traditional parallel circuit and a T-matching network for secondary side is proposed. With this method, a boosted voltage can be output to the load, since this topology has a resonant enhancement effect, and high Q value can be obtained at a low resonant frequency and low coil inductance. This feature makes it more suitable for weak coupling WPT applications. Besides, the proposed topology shows good frequency stability and adaptability to variations of load. Experimental results show that the output voltage gain improves by 757% compared with traditional series circuit, and reaches 85% total efficiency when the coupling coefficient is 0.046.
A coupling model for quasi-normal modes of photonic resonators
Vial, Benjamin; Hao, Yang
2016-11-01
We develop a model for the coupling of quasi-normal modes in open photonic systems consisting of two resonators. By expressing the modes of the coupled system as a linear combination of the modes of the individual particles, we obtain a generalized eigenvalue problem involving small size dense matrices. We apply this technique to dielectric rod dimmer of rectangular cross section for transverse electric polarization in a two-dimensional setup. The results of our model show excellent agreement with full wave finite element simulations. We provide a convergence analysis, and a simplified model with a few modes to study the influence of the relative position of the two resonators. This model provides interesting physical insights on the coupling scheme at stake in such systems and pave the way for systematic and efficient design and optimization of resonances in more complicated systems, for applications including sensing, antennae and spectral filtering.
Protected quantum computation with multiple resonators in ultrastrong coupling circuit QED
Nataf, Pierre
2011-01-01
We investigate theoretically the dynamical behavior of a qubit obtained with the two ground eigenstates of an ultrastrong coupling circuit-QED system consisting of a finite number of Josephson fluxonium atoms inductively coupled to a transmission line resonator. We show an universal set of quantum gates by using multiple transmission line resonators (each resonator represents a single qubit). We discuss the intrinsic 'anisotropic' nature of noise sources for fluxonium artificial atoms. Through a master equation treatment with colored noise and manylevel dynamics, we prove that, for a general class of anisotropic noise sources, the coherence time of the qubit and the fidelity of the quantum operations can be dramatically improved in an optimal regime of ultrastrong coupling, where the ground state is an entangled photonic 'cat' state.
Randrianandrasana, Michel; Wei, Xueyong; Lowe, David
2010-01-01
The global and local synchronisation of a square lattice composed of alternating Duffing resonators and van der Pol oscillators coupled through displacement is studied. The lattice acts as a sensing device in which the input signal is characterised by an external driving force that is injected into the system through a subset of the Duffing resonators. The parameters of the system are taken from MEMS devices. The effects of the system parameters, the lattice architecture and size are discussed.
Dipolariton formation in quantum dot molecules strongly coupled to optical resonators
Domínguez, Marlon S; Ramírez, Hanz Y
2016-01-01
In this theoretical work, we study a double quantum dot interacting strongly with a microcavity, while undergoing resonant tunneling. Effects of interdot tunneling on the light-matter hybridized states are determined, and tunability of their brightness degrees and associated dipole moments is demonstrated. These results predict dipolariton generation in artificial molecules coupled to optical resonators, and provide a promising scenario for control of emission efficiency and coherence times of exciton polaritons.
Mechanics and Resonance of the Cyanobacterial Circadian Oscillator
Karafyllidis, Ioannis G
2012-01-01
Recent experiments elucidated the structure and function of the cyanobacterial circadian oscillator, which is driven by sunlight intensity variation and therefore by Earth's rotation. It is known that cyanobacteria appeared about 3.5 billion years ago and that Earth's rotational speed is continuously decreasing because of tidal friction. What is the effect of the continuous slowdown of Earth's rotation on the operation of the cyanobacterial oscillator? To answer this question we derived the oscillator's equation of motion directly from experimental data, coupled it with Earth's rotation and computed its natural periods and its resonance curve. The results show that there are two resonance peaks of the "cyanobacterial oscillator-rotating Earth" system, indicating that cyanobacteria used more efficiently the solar energy during the geological period in which the day length varied from about 11 to 15 hours and make more efficient use of solar energy at the geological period which started with a day length of 21 ...
Photothermal Infrared Spectroscopy of Airborne Samples with Mechanical String Resonators
Yamada, Shoko; Schmid, Silvan; Larsen, Tom
2013-01-01
the mid-infrared range. As a proof-of-concept, we sample and analyze polyvinylpyrrolidone (PVP) and the IR spectrum measured by photothermal spectroscopy matches the reference IR spectrum measured by an FTIR spectrometer. We further identify the organic surface coating of airborne TiO2 nanoparticles......Micromechanical photothermal infrared spectroscopy is a promising technique, where absorption-related heating is detected by frequency detuning of microstring resonators. We present photothermal infrared spectroscopy with mechanical string resonators providing rapid identification of femtogram......-scale airborne samples. Airborne sample material is directly collected on the microstring with an efficient nondiffusion limited sampling method based on inertial impaction. Resonance frequency shifts, proportional to the absorbed heat in the microstring, are recorded as monochromatic IR light is scanned over...
Lin, Yanqin; Lin, Liangjie; Wei, Zhiliang; Zhong, Jianhui; Chen, Zhong
2016-12-01
To acquire single voxel localized one-dimensional (1) H magnetic resonance spectroscopy (MRS) without J coupling modulations, free from amplitude and phase distortions. A pulse sequence, named PRESSIR, is developed for volume localized MRS without J modulations at arbitrary echo time (TE). The J coupling evolution is suppressed by the J-refocused module that uses a 90° pulse at the midpoint of a double spin echo. The localization performance of the PRESSIR sequence was tested with a two-compartment phantom. The proposed sequence shows similar voxel localization accuracy as PRESS. Both PRESSIR and PRESS sequences were performed on MRS brain phantom and pig brain tissue. PRESS spectra suffer from amplitude and phase distortions due to J modulations, especially under moderate and long TEs, while PRESSIR spectra are almost free from distortions. The PRESSIR sequence proposed herein enables the acquisition of single voxel in-phase MRS within a single scan. It allows an enhanced signal intensity of J coupling metabolites and reducing undesired broad resonances with short T2s while suppressing J modulations. Moreover, it provides an approach for direct measurement of nonoverlapping J coupling peaks and of transverse relaxation times T2s. Magn Reson Med 76:1661-1667, 2016. © 2015 International Society for Magnetic Resonance in Medicine. © 2015 International Society for Magnetic Resonance in Medicine.
Finite size effect on spread of resonance frequencies in arrays of coupled vortices
Vogel, Andreas; Drews, André; Im, Mi-Young; Fischer, Peter; Meier, Guido
2011-01-25
Dynamical properties of magnetic vortices in arrays of magnetostatically coupled ferromagnetic disks are studied by means of a broadband ferromagnetic-resonance (FMR) setup. Magnetic force microscopy and magnetic transmission soft X-ray microscopy are used to image the core polarizations and the chiralities which are both found to be randomly distributed. The resonance frequency of vortex-core motion strongly depends on the magnetostatic coupling between the disks. The parameter describing the relative broadening of the absorption peak observed in the FMR transmission spectra for a given normalized center-to-center distance between the elements is shown to depend on the size of the array.
A magneto-optical isolator based on series-coupled race-track resonators
Qi, Wei; Jin, Yichang; Yu, Hui; Jiang, Xiaoqing
2015-01-01
In this paper, we propose a novel kind of magneto-optical (MO) isolators based on series-coupled race-track resonators. The perturbation theory is used to calculate the non-reciprocal phase shift (NRPS) induced by the MO effect. The numerical result indicates that the isolation is greatly enhanced by the box-like spectra of series-coupled resonators. Optical isolation ratio for the first, second, and third order devices are 7.8, 21, and 36.2 dB, respectively.
Wolfe, Michael; Kestner, Jason
Electrons confined in lateral quantum dots are promising candidates for scalable quantum bits. Particularly, singlet-triplet qubits can entangle electrostatically and offer long coherence times due to their weak interactions with the environment. However, fast two-qubit operations are challenging. We examine the dynamics of singlet triplet qubits capacitively coupled to a classical transmission line resonator driven near resonance. We numerically simulate the dynamics of the von Neumann entanglement entropy and investigate parameters of the coupling element that optimizes the operation time for the qubit.
Bian, Nicolas H; Ratcliffe, Heather
2015-01-01
Of particular interest for radio and hard X-ray diagnostics of accelerated electrons during solar flares is the understanding of the basic non-linear mechanisms regulating the relaxation of electron beams propagating in turbulent plasmas. In this work, it is shown that in addition to scattering of beam electrons, scattering of the beam-generated Langmuir waves via for instance mode-coupling, can also result in broadening of the wave-particle resonance. We obtain a resonance-broadened version of weak-turbulence theory with mode-coupling to ion-sound modes. Resonance broadening is presented here as a unified framework which can quantitatively account for the reduction and possible suppression of the beam instability due to background scattering of the beam electrons themselves or due to scattering of the beam-generated Langmuir waves in fluctuating plasmas. Resonance broadening being essentially equivalent to smoothing of the electron phase-space distribution, it is used to construct an intuitive physical pictu...
1:2 INTERNAL RESONANCE OF COUPLED DYNAMIC SYSTEM WITH QUADRATIC AND CUBIC NONLINEARITIES
陈予恕; 杨彩霞; 吴志强; 陈芳启
2001-01-01
The 1:2 internal resonance of coupled dynamic system with quadratic and cubic nonlinearities is studied. The normal forms of this system in 1: 2 internal resonance were derived by using the direct method of normal form. In the normal forms, quadratic and cubic nonlinearities were remained. Based on a new convenient transformation technique, the 4-dimension bifurcation equations were reduced to 3-dimension. A bifurcation equation with one-dimension was obtained. Then the bifurcation behaviors of a universal unfolding were studied by using the singularity theory. The method of this paper can be applied to analyze the bifurcation behavior in strong internal resonance on 4-dimension center manifolds.
Phase-noise-induced resonance in arrays of coupled excitable neural models.
Xiaoming Liang; Liang Zhao
2013-08-01
Recently, it is observed that, in a single neural model, phase noise (time-varying signal phase) arising from an external stimulating signal can induce regular spiking activities even if the signal is subthreshold. In addition, it is also uncovered that there exists an optimal phase noise intensity at which the spiking rhythm coincides with the frequency of the subthreshold signal, resulting in a phase-noise-induced resonance phenomenon. However, neurons usually do not work alone, but are connected in the form of arrays or blocks. Therefore, we study the spiking activity induced by phase noise in arrays of globally and locally coupled excitable neural models. We find that there also exists an optimal phase noise intensity for generating large neural response and such an optimal value is significantly decreased compared to an isolated single neuron case, which means the detectability in response to the subthreshold signal of neurons is sharply improved because of the coupling. In addition, we reveal two new resonance behaviors in the neuron ensemble with the presence of phase noise: there exist optimal values of both coupling strength and system size, where the coupled neurons generate regular spikes under subthreshold stimulations, which are called as coupling strength and system size resonance, respectively. Finally, the dependence of phase-noise-induced resonance on signal frequency is also examined.
Resonance tuning due to Coulomb interaction in strong near-field coupled metamaterials
Roy Chowdhury, Dibakar, E-mail: dibakar.roychowdhury@anu.edu.au [Center for Sustainable Energy Systems, College of Engineering and Computer Science, Australian National University, Canberra 0200 (Australia); College of Engineering, Mahindra Ecole Centrale, Jeedimetla, Hyderabad, 500043 (India); Xu, Ningning; Zhang, Weili [School of Electrical Engineering and Computer Science, Oklahoma State University, Stillwater, Oklahoma 87074 (United States); Singh, Ranjan, E-mail: ranjans@ntu.edu.sg [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
2015-07-14
Coulomb's law is one of the most fundamental laws of physics that describes the electrostatic interaction between two like or unlike point charges. Here, we experimentally observe a strong effect of Coulomb interaction in tightly coupled terahertz metamaterials where the split-ring resonator dimers in a unit cell are coupled through their near fields across the capacitive split gaps. Using a simple analytical model, we evaluated the Coulomb parameter that switched its sign from negative to positive values indicating the transition in the nature of Coulomb force from being repulsive to attractive depending upon the near field coupling between the split ring resonators. Apart from showing interesting effects in the strong coupling regime between meta-atoms, Coulomb interaction also allows an additional degree of freedom to achieve frequency tunable dynamic metamaterials.
Strange baryonic resonances and resonances coupling to strange hadrons at SIS energies
Fabbietti, L. [e12, Physik Department Technische Universität München Excellence Cluster “Origin and Structure of the Universe” (Germany)
2016-01-22
The role played by baryonic resonances in the production of final states containing strangeness for proton-proton reactions at 3.5 GeV measured by HADES is discussed by means of several very different measurements. First the associate production of Δ resonances accompanying final states with strange hadrons is presented, then the role of interferences among N{sup *} resonances, as measured by HADES for the first time, is summarised. Last but not least the role played by heavy resonances, with a mass larger than 2 GeV/c{sup 2} in the production of strange and non-strange hadrons is discussed. Experimental evidence for the presence of a Δ(2000){sup ++} are presented and hypotheses are discussed employing the contribution of similar objects to populate the excesses measured by HADES for the Ξ in A+A and p+A collisions and in the dilepton sector for A+A collisions. This extensive set of results helps to better understand the dynamic underlaying particle production in elementary reactions and sets a more solid basis for the understanding of heavy ion collisions at the same energies and even higher as planned at the FAIR facility.
Mechanical coupling for a rotor shaft assembly of dissimilar materials
Shi, Jun; Bombara, David; Green, Kevin E.; Bird, Connic; Holowczak, John
2009-05-05
A mechanical coupling for coupling a ceramic disc member to a metallic shaft includes a first wedge clamp and a second wedge clamp. A fastener engages a threaded end of a tie-bolt to sandwich the ceramic disc between the wedge clamps. An axial spring is positioned between the fastener and the second wedge clamp to apply an axial preload along the longitudinal axis. Another coupling utilizes a rotor shaft end of a metallic rotor shaft as one wedge clamp. Still another coupling includes a solid ceramic rotor disc with a multiple of tie-bolts radially displaced from the longitudinal axis to exert the preload on the solid ceramic rotor disc.
Thermo-mechanical coupling strategies in elastic-plastic problems
Vaz, M.; Lange, M. R.
2017-03-01
Modeling strategies aimed at thermo-mechanical coupled problems has been developed for a wide range of engineering applications. Staggered-type coupling procedures have been largely used in materials processing operations, especially in commercial codes, owing to their simplicity and flexibility. The present work shows that, in thermo-plastic problems, the classical implementation of the most common coupling procedure may present accuracy issues and time-stepping dependency. Numerical experiments indicate that an iterative coupling scheme constitutes a viable and simple approach to this class of problems.
Cascade of parametric resonances in coupled Josephson junctions
Shukrinov, Yu. M.; Azemtsa-Donfack, H.; Rahmonov, I. R.; Botha, A. E.
2016-06-01
We found that the coupled system of Josephson junctions under external electromagnetic radiation demonstrates a cascade of parametric instabilities. These instabilities appear along the IV characteristics within bias current intervals corresponding to Shapiro step subharmonics and lead to charging in the superconducting layers. The amplitudes of the charge oscillations increase with increasing external radiation power. We demonstrate the existence of longitudinal plasma waves at the corresponding bias current values. An essential advantage of the parametric instabilities in the case of subharmonics is the lower amplitude of radiation that is needed for the creation of the longitudinal plasma wave. This fact gives a unique possibility to create and control longitudinal plasma waves in layered superconductors. We propose a novel experiment for studying parametric instabilities and the charging of superconducting layers based on the simultaneous variation of the bias current and radiation amplitude.
Liu, Yu-Long; Zhang, Jing; Özdemir, Şahin Kaya; Yang, Lan; Nori, Franco; Liu, Yu-xi
2016-01-01
We theoretically study a strongly-driven optomechanical system which consists of a passive optical cavity and an active mechanical resonator. When the optomechanical coupling strength is varied, phase transitions, which are similar those observed in $\\mathcal{PT}$-symmetric systems, are observed. We show that the optical transmission can be controlled by changing the gain of the mechanical resonator and loss of the optical cavity mode. Especially, we find that: (i) for balanced gain and loss, optical amplification and absorption can be tuned by changing the optomechanical coupling strength through a control field; (ii) for unbalanced gain and loss, even with a tiny mechanical gain, both optomechanically-induced transparency and anomalous dispersion can be observed around a critical point, which exhibits an ultra-long group delay. The time delay $\\tau$ can be optimized by regulating the optomechanical coupling strength through the control field and improved up to several orders of magnitude ($\\tau\\sim2$ $\\math...
Electrochemical/mechanical coupling in ion-conducting soft matter.
Kusoglu, Ahmet; Weber, Adam Z
2015-11-19
Mechanical and electrochemical phenomena exhibit many interesting multidirectional couplings in ion-exchange soft matter due to their intrinsic material physiochemical states and responses to environmental stressors. In this Perspective, such coupling is explored in terms of recent studies with a focus on the degradation of polymer-electrolyte fuel-cell membranes. In addition, (electro)chemical-mechanical coupling of ion-conducting polymers in other applications is also introduced, as there is a research need to explore the interactions between these often wrongly assumed disparate fields in order to optimize, exploit, and discover new technologies and applications.
Shoman, Hossam; Dahlem, Marcus S.
2015-02-01
Microring resonators are important elements in a wide variety of optical systems, ranging from optical switches and tunable filterbanks to optical sensors. In these structures, the resonant frequencies are normally controlled by tuning the effective index of refraction. In optical switches and filters, this has traditionally been achieved through electro-optic or thermo-optic effects. In sensors, the effective refractive index is changed by the presence of the measurand. Adding a mechanical degree of freedom to these optical systems allows additional evanescent frequency tuning. In particular, the presence of a cantilever in the near-field of the optical mode can tune the effective refractive index. A specific cantilever displacement can therefore induce a desired resonant frequency shift. Alternatively, a measured shift in the resonant frequency can be associated with a cantilever displacement, and be used for pressure or acceleration sensing. In this paper, we explore a geometry that can be used for controlling the resonant frequency of a microring resonator through evanescent field perturbation, using a cantilever defined in the same silicon layer as the optical waveguides, in a silicon-on-insulator platform. The effects of the lateral gap size between the optical waveguide and the cantilever, and the cantilever vertical displacement, on both the resonant frequency and quality factor of the resonator, are evaluated through finite-difference timedomain computations for wavelengths centered at 1550 nm. The presence of the cantilever in the near-field of the optical mode changes the effective refractive index, resulting in frequency tuning, but also lowers the quality factor due to additional coupling into the membrane.
General mechanism for amplitude death in coupled systems.
Resmi, V; Ambika, G; Amritkar, R E
2011-10-01
We introduce a general mechanism for amplitude death in coupled synchronizable dynamical systems. It is known that when two systems are coupled directly, they can synchronize under suitable conditions. When an indirect feedback coupling through an environment or an external system is introduced in them, it is found to induce a tendency for antisynchronization. We show that, for sufficient strengths, these two competing effects can lead to amplitude death. We provide a general stability analysis that gives the threshold values for onset of amplitude death. We study in detail the nature of the transition to death in several specific cases and find that the transitions can be of two types--continuous and discontinuous. By choosing a variety of dynamics, for example, periodic, chaotic, hyperchaotic, and time-delay systems, we illustrate that this mechanism is quite general and works for different types of direct coupling, such as diffusive, replacement, and synaptic couplings, and for different damped dynamics of the environment.
Jiawei eWANG
2015-04-01
Full Text Available Silicon nitride (SiN is a promising material platform for integrating photonic components and microfluidic channels on a chip for label-free, optical biochemical sensing applications in the visible to near-infrared wavelengths. The chip-scale SiN-based optofluidic sensors can be compact due to a relatively high refractive index contrast between SiN and the fluidic medium, and low-cost due to the complementary metal-oxide-semiconductor (CMOS-compatible fabrication process. Here, we demonstrate SiN-based integrated optofluidic biochemical sensors using a coupled-resonator optical waveguide (CROW in the visible wavelengths. The working principle is based on imaging in the far field the out-of-plane elastic-light-scattering patterns of the CROW sensor at a fixed probe wavelength. We correlate the imaged pattern with reference patterns at the CROW eigenstates. Our sensing algorithm maps the correlation coefficients of the imaged pattern with a library of calibrated correlation coefficients to extract a minute change in the cladding refractive index. Given a calibrated CROW, our sensing mechanism in the spatial domain only requires a fixed-wavelength laser in the visible wavelengths as a light source, with the probe wavelength located within the CROW transmission band, and a silicon digital charge-coupled device (CCD / CMOS camera for recording the light scattering patterns. This is in sharp contrast with the conventional optical microcavity-based sensing methods that impose a strict requirement of spectral alignment with a high-quality cavity resonance using a wavelength-tunable laser. Our experimental results using a SiN CROW sensor with eight coupled microrings in the 680nm wavelength reveal a cladding refractive index change of ~1.3 × 10^-4 refractive index unit (RIU, with an average sensitivity of ~281 ± 271 RIU-1 and a noise-equivalent detection limit (NEDL of 1.8 ×10^-8 RIU ~ 1.0 ×10^-4 RIU across the CROW bandwidth of ~1 nm.
On the heating of inductively coupled resonators (stents) during MRI examinations.
Busch, Martin; Vollmann, Wolfgang; Bertsch, Thomas; Wetzler, Rainer; Bornstedt, Axel; Schnackenburg, Bernhard; Schnorr, Jörg; Kivelitz, Dietmar; Taupitz, Matthias; Grönemeyer, Dietrich
2005-10-01
Stents that have been implanted to preserve the results of vascular dilatation are frequently affected by in-stent restenosis, which ideally should be followed up by a noninvasive diagnostic modality. Active MRI stents can enable this kind of follow-up, while normal metallic stents can not. The prototype stents investigated in this study were designed as electric resonating circuits without a direct connection to the MR imager, and function as inductively coupled transmit coils. The model of a long solenoid coil is used to describe the additional power loss caused by such resonators. The theoretically estimated temperature increase is verified by measurements for different resonators and discussed for worst-case conditions. The RF power absorption of an active resonator is negligible compared to the total power absorbed during MRI. The local temperature increase observed for prototypes embedded in phantoms is in a range that excludes direct tissue damage. However, ruptures in the conducting structure of a resonator can cause hot spots, which may establish a high local temperature. This hazard can be reduced by designing resonators with a low quality (Q) factor or by setting the circuit slightly off resonance; however, this would lower the nominal amplification for which the resonator was designed.
Nitzan, Sarah H; Zega, Valentina; Li, Mo; Ahn, Chae H; Corigliano, Alberto; Kenny, Thomas W; Horsley, David A
2015-01-01
Parametric amplification, resulting from intentionally varying a parameter in a resonator at twice its resonant frequency, has been successfully employed to increase the sensitivity of many micro- and nano-scale sensors. Here, we introduce the concept of self-induced parametric amplification, which arises naturally from nonlinear elastic coupling between the degenerate vibration modes in a micromechanical disk-resonator, and is not externally applied. The device functions as a gyroscope wherein angular rotation is detected from Coriolis coupling of elastic vibration energy from a driven vibration mode into a second degenerate sensing mode. While nonlinear elasticity in silicon resonators is extremely weak, in this high quality-factor device, ppm-level nonlinear elastic effects result in an order-of-magnitude increase in the observed sensitivity to Coriolis force relative to linear theory. Perfect degeneracy of the primary and secondary vibration modes is achieved through electrostatic frequency tuning, which also enables the phase and frequency of the parametric coupling to be varied, and we show that the resulting phase and frequency dependence of the amplification follow the theory of parametric resonance. We expect that this phenomenon will be useful for both fundamental studies of dynamic systems with low dissipation and for increasing signal-to-noise ratio in practical applications such as gyroscopes.
Zhang, Weifeng; Li, Wangzhe; Yao, Jianping
2016-06-01
A grating-based Fabry-Perot (FP) cavity-coupled microring resonator on a silicon chip is reported to demonstrate an all-optically tunable Fano resonance. In the device, an add-drop microring resonator (MRR) is employed, and one of the two bus waveguides is replaced by an FP cavity consisting of two sidewall Bragg gratings. By choosing the parameters of the gratings, the resonant mode of the FP cavity is coupled to one of the resonant modes of the MRR. Due to the coupling between the resonant modes, a Fano resonance with an asymmetric line shape resulted. Measurement results show a Fano resonance with an extinction ratio of 22.54 dB, and a slope rate of 250.4 dB/nm is achieved. A further study of the effect of the coupling on the Fano resonance is performed numerically and experimentally. Thanks to the strong light-confinement capacity of the MRR and the FP cavity, a strong two-photon absorption induced nonlinear thermal-optic effect resulted, which is used to tune the Fano resonance optically.
Miniature wideband filter based on coupled-line sections and quasi-lumped element resonator
Zhurbenko, Vitaliy; Krozer, Viktor; Meincke, Peter
2007-01-01
A new design of a wideband bandpass filter is proposed, based on coupled-line sections and quasi-lumped element resonator, taking advantage of the last one to introduce two transmission zeros and suppress a spurious response. The proposed filter demonstrates significantly improved characteristics...
Kohei Mizuno
2015-10-01
Full Text Available Since 2007, resonant coupling wireless power transfer (WPT technology has been attracting attention and has been widely researched for practical use. Moreover, dosimetric evaluation has also been discussed to evaluate the potential health risks of the electromagnetic field from this WPT technology based on the International Commission on Non-Ionizing Radiation Protection (ICNIRP guidelines. However, there has not been much experimental evaluation of the potential health risks of this WPT technology. In this study, to evaluate whether magnetic resonant coupling WPT induces cellular stress, we focused on heat shock proteins (Hsps and determined the expression level of Hsps 27, 70 and 90 in WI38VA13 subcloned 2RA human fibroblast cells using a western blotting method. The expression level of Hsps under conditions of magnetic resonant coupling WPT for 24 h was not significantly different compared with control cells, although the expression level of Hsps for cells exposed to heat stress conditions was significantly increased. These results suggested that exposure to magnetic resonant coupling WPT did not cause detectable cell stress.
Fully reconfigurable coupled ring resonator-based bandpass filter for microwave signal processing
Taddei, Caterina; Zhuang, L.; Hoekman, M.; Leinse, Arne; Oldenbeuving, Ruud; van Dijk, Paul; Roeloffzen, C.G.H.
2014-01-01
We propose and demonstrate an integrated coupled resonator optical waveguide (CROW)-based bandpass filter in TriPleX™ technology for microwave photonic signal processing. The system principle allows the selection of a channel in a dense-frequency-division subcarrier satellite communication system.
Microwave Power Transmission Using Electromagnetic Coupling of Open-Ring Resonators
2012-11-01
Ao, I. Awai and Y. Ohno, “Wireless Inter-Chip Signal Transmission by Electromagnetic Coupling of Open-Ring Resonators,” Japanese Journal of Applied Physics , vol...Y Hu, H. Kawai, N. Shinohara, N. Niwa, and Y. Ohno, : GaN Schottky Diodes for Microwave Power Rectification, Japanese Journal of Applied Physics , Vol
Yan-Mei Kang; Mei Wang; Yong Xie
2012-01-01
With coupled weakly-damped periodically driven bistable oscillators subjected to additive and multiplicative noises under concern,the objective of this paper is to check to what extent the resonant point predicted by the Gaussian distribution assumption can approximate the simulated one.The investigation based on the dynamical mean-field approximation and the direct simulation demonstrates that the predicted resonant point and the simulated one are basically coincident for the case of pure additive noise,but for the case including multiplicative noise the situation becomes somewhat complex.Specifically speaking,when stochastic resonance (SR) is observed by changing the additive noise intensity,the predicted resonant point is lower than the simulated one; nevertheless,when SR is observed by changing the multiplicative noise intensity,the predicted resonant point is higher than the simulated one.Our observations imply that the Gaussian distribution assumption can not exactly describe the actual situation,but it is useful to some extent in predicting the low-frequency stochastic resonance of the coupled weakly-damped bistable oscillator.
An asymmetric resonant coupling wireless power transmission link for Micro-Ball Endoscopy.
Sun, Tianjia; Xie, Xiang; Li, Guolin; Gu, Yingke; Deng, Yangdong; Wang, Ziqiang; Wang, Zhihua
2010-01-01
This paper investigates the design and optimization of a wireless power transmission link targeting Micro-Ball Endoscopy applications. A novel asymmetric resonant coupling structure is proposed to deliver power to an endoscopic Micro-Ball system for image read-out after it is excreted. Such a technology enables many key medical applications with stringent requirements for small system volume and high power delivery efficiency. A prototyping power transmission sub-system of the Micro-Ball system was implemented. It consists of primary coil, middle resonant coil, and cube-like full-direction secondary receiving coils. Our experimental results proved that 200mW of power can be successfully delivered. Such a wireless power transmission capability could satisfy the requirements of the Micro-Ball based endoscopy application. The transmission efficiency is in the range of 41% (worst working condition) to 53% (best working condition). Comparing to conventional structures, Asymmetric Resonant Coupling Structure improves power efficiency by 13%.
Limiting Phase Trajectories and Resonance Energy Transfer in a System of Two Coupled Oscillators
L. I. Manevitch
2010-01-01
Full Text Available We study a problem of energy exchange in a system of two coupled oscillators subject to 1 : 1 resonance. Our results exploit the concept of limiting phase trajectories (LPTs. The LPT, associated with full energy transfer, is, in certain sense, an alternative to nonlinear normal modes characterized by conservation of energy. We consider two benchmark examples. As a first example, we construct an LPT and examine the convergence to stationary oscillations for a Duffing oscillator subjected to resonance harmonic excitation. As a second example, we treat resonance oscillations in a system of two nonlinearly coupled oscillators. We demonstrate the reduction of the equations of motion to an equation of a single oscillator. It is shown that the most intense energy exchange and beating arise when motion of the equivalent oscillator is close to an LPT. Damped beating and the convergence to rest in a system with dissipation are demonstrated.
Britzger, Michael; Khalaidovski, Alexander; Friedrich, Daniel; Kroker, Stefanie; Brueckner, Frank; Kley, Ernst-Bernhard; ennermann, Andreas Tu; Danzmann, Karsten; Schnabel, Roman
2012-01-01
Michelson-type laser-interferometric gravitational-wave (GW) observatories employ very high light powers as well as transmissively- coupled Fabry-Perot arm resonators in order to realize high measurement sensitivities. Due to the absorption in the transmissive optics, high powers lead to thermal lensing and hence to thermal distortions of the laser beam profile, which sets a limit on the maximal light power employable in GW observatories. Here, we propose and realize a Michelson-type laser interferometer with arm resonators whose coupling components are all-reflective second-order Littrow gratings. In principle such gratings allow high finesse values of the resonators but avoid bulk transmission of the laser light and thus the corresponding thermal beam distortion. The gratings used have three diffraction orders, which leads to the creation of a second signal port. We theoretically analyze the signal response of the proposed topology and show that it is equivalent to a conventional Michelson-type interferomet...
A coupled-channel analysis of $K\\Lambda$ production in the nucleon resonance region
Shklyar, V; Mosel, U
2005-01-01
A unitary coupled-channel effective Lagrangian model is applied to the combined analysis of the $(\\pi,\\gamma) N \\to K\\Lambda$ reactions in the energy region up to 2 GeV. To constrain the resonance couplings to the $K\\Lambda$ final state the recent photoproduction data obtained by the SAPHIR, SPring-8, and CLAS groups are included into the calculations. The main resonance contributions to the process stem from the $S_{11}(1650)$, $P_{13}(1720)$, and $P_{13}(1900)$ states. The second bump at 1.9 GeV seen in the photoproduction cross section data is described as a coherent sum of the resonance and background contributions. The prediction for the beam polarization observable is presented.
Coupling InSb quantum dots to a superconducting microwave resonator
Cassidy, Maja; Kammhuber, Jakob; Car, Diana; Plissard, Sebastien; Bakkers, Erik; Dicarlo, Leo; Kouwenhoven, Leo
2014-03-01
We present measurements of a superconducting half-wave resonator coupled to two InSb nanowire quantum dots. Precise nanowire alignment at the electric field antinodes at opposite ends of the microwave cavity allows for a maximal electric field along the wire axis, without compromising the intrinsic quality factor of the cavity. This architecture may be useful for reaching the strong coupling limit between a single spin and a microwave photon, paving the way to on-chip coupling of single spins for quantum information processing.
Stochastic Huge-Resonance Caused by Coupling for a Globally Coupled Linear System
LI Jing-Hui
2009-01-01
In the paper, we investigate a globally coupled linear system with finite subunits subject to temporal periodic force and with multiplicative dichotomous noise.It is shown that, the global coupling among the subunits can hugely enhance the phenomenon of SR for the amplitude of the average mean field as the functions of the transition rate of the noise and that as the function of the frequency of the signal respectively.
Optimal piezo-electro-mechanical coupling to control plate vibrations
Alessandroni, S; Frezza, F
2010-01-01
A new way of coupling electrical and mechanical waves, using piezoelectric effect, is presented here. Since the energy exchange between two systems supporting wave propagation is maximum when their evolution is governed by similar equations, hence, an optimal electromechanical coupling is obtained by designing an electric network which is "analog" to the mechanical structure to be controlled. In this paper, we exploit this idea to enhance the coupling, between a Kirchhoff-Love plate and one possible synthesis of its circuital analog, as obtained by means of a set of piezoelectric actuators uniformly distributed upon the plate. It is shown how this approach allows for an optimal energy exchange between the mechanic and the electric forms independent of the modal evolution of the structure. Moreover, we show how an efficient electric dissipation of the mechanical energy can be obtained adding dissipative elements in the electric network.
Split and merge of left-right circular polarized light through coupled magnetic resonators
Wang, Jijun; Cao, Jing; Zhu, Min; Zhu, Zhipan [Jiangsu Univ., Zhenjiang (China). Faculty of Science; Fang, Yun-tuan [Jiangsu Univ., Zhenjiang (China). School of Computer Science and Telecommunication Engineering
2012-08-15
In order to obtain the means to control light polarization, we designed a structure of coupled magnetic resonators and studied its transmission properties by the 4 x 4 transfer matrix method. The incidence of linearly polarized light results in two transmission resonant peaks of left-handed circular polarization at shorter wavelengths and two transmission resonant peaks of right-handed circular polarization at longer wavelengths, respectively. Through adjusting the magnetizations, the inner left-handed circular polarization and right-handed circular polarization can be merged into one linear polarization, while the two outside resonant peaks keep their circular polarization. The polarized direction of the output linearly polarized light can be controlled by the polarized direction of incidence light. The incidence light with one polarization can output light with three kinds of polarizations through the designed structure. (orig.)
Research on coupling between thermoacoustic resonance pipe and piezoelectric acoustic source
FAN Li; ZHANG Shuyi; WANG Benren
2007-01-01
Piezoelectric loudspeakers have been used in thermoacoustic refrigerators for operating at the high frequency to miniaturize the system. Then the coupling between the piezoelectric loudspeaker and resonance pipe becomes an important factor for improving the performances of the system. By the equivalent circuit model, the expressions of the acoustic output power and electroacoustic transfer efficiency at a low operating frequency are obtained, and then the structures of the piezoelectric loudspeaker and resonance pipe, as well as the operating frequency, are optimized to achieve a high electroacoustic transfer efficiency and a large acoustic output power. It is also shown that when the total reactance of the system equals zero, the resonance frequency of the resonance pipe is the optimized operating frequency and a high acoustic output power can be achieved. However, the highest transfer efficiency and largest acoustic power cannot be obtained simultaneously, therefore a trade-off condition must be adopted.
An a0 resonance in strongly coupled π η , K K ¯ scattering from lattice QCD
Dudek, Jozef J.; Edwards, Robert G.; Wilson, David J.; Hadron Spectrum Collaboration
2016-05-01
We present the first calculation of coupled-channel meson-meson scattering in the isospin =1 , G -parity negative sector, with channels π η , K K ¯ and π η', in a first-principles approach to QCD. From the discrete spectrum of eigenstates in three volumes extracted from lattice QCD correlation functions we determine the energy dependence of the S -matrix, and find that the S -wave features a prominent cusplike structure in π η →π η close to the K K ¯ threshold coupled with a rapid turn-on of amplitudes leading to the K K ¯ final state. This behavior is traced to an a0(980 )-like resonance, strongly coupled to both π η and K K ¯ , which is identified with a pole in the complex energy plane, appearing on only a single unphysical Riemann sheet. Consideration of D -wave scattering suggests a narrow tensor resonance at higher energy.
Chirality-sensitive nuclear magnetic resonance effects induced by indirect spin-spin coupling
Garbacz, P.; Buckingham, A. D.
2016-11-01
It is predicted that, for two spin-1/2 nuclei coupled by indirect spin-spin coupling in a chiral molecule, chirality-sensitive induced electric polarization can be observed at the frequencies equal to the sum and difference between the spin resonance frequencies. Also, an electric field oscillating at the difference frequency can induce spin coherences which allow the direct discrimination between enantiomers by nuclear magnetic resonance. The dominant contribution to the magnitude of these expected chiral effects is proportional to the permanent electric dipole moment and to the antisymmetric part of the indirect spin-spin coupling tensor of the chiral molecule. Promising compounds for experimental tests of the predictions are derivatives of 1,3-difluorocyclopropene.
A coupling model for quasi-normal modes of photonic resonators
Vial, Benjamin
2016-01-01
We develop a model for the coupling of quasi-normal modes in open photonic systems consisting of two resonators. By expressing the modes of the coupled system as a linear combination of the modes of the individual particles, we obtain a generalized eigenvalue problem involving small size dense matrices. We apply this technique to a 2D problem of a high index rod dimmer of rectangular cross section for Transverse Electric (TE) polarization. The results of our model are compared with full-wave finite element simulations and show a good agreement for the four lowest eigenvalues by taking into account the two lowest eigenfrequencies of the isolated rods. This model provides interesting physical insights on the coupling scheme at stake in such systems and pave the way for the design and optimization of resonances in more complicated systems, including the engineering of metamaterial unit cells.
Yudi, Xiao; Xingkui, Mao; Mao, Lin
2017-01-01
The coupled magnetic resonant unit (CMRU) has great effect on the transmitting power capability and efficiency of magnetic resonant wireless power transfer system. The key objective i.e. the efficiency coefficient kQ is introduced in the design of CMRU or the coupled windings based on the mutual ...
A micro-coupling for micro mechanical systems
Li, Wei; Zhou, Zhixiong; Zhang, Bi; Xiao, Yunya
2016-05-01
The error motions of micro mechanical systems, such as micro-spindles, increase with the increasing of the rotational speed, which not only decreases the rotational accuracy, but also promotes instability and limits the maximum operational speed. One effective way to deal with it is to use micro-flexible couplings between the drive and driven shafts so as to reduce error motions of the driven shaft. But the conventional couplings, such as diaphragm couplings, elastomeric couplings, bellows couplings, and grooved couplings, etc, cannot be directly used because of their large and complicated structures. This study presents a novel micro-coupling that consists of a flexible coupling and a shape memory alloy (SMA)-based clamp for micro mechanical systems. It is monolithic and can be directly machined from a shaft. The study performs design optimization and provides manufacturing considerations, including thermo-mechanical training of the SMA ring for the desired Two-Way-Shape-Memory effect (TWSMe). A prototype micro-coupling and a prototype micro-spindle using the proposed coupling are fabricated and tested. The testing results show that the prototype micro-coupling can bear a torque of above 5 N • mm and an axial force of 8.5 N and be fitted with an SMA ring for clamping action at room temperature (15 °C) and unclamping action below-5 °C. At the same time, the prototype micro-coupling can work at a rotational speed of above 200 kr/min with the application to a high-speed precision micro-spindle. Moreover, the radial runout error of the artifact, as a substitute for the micro-tool, is less than 3 μm while that of turbine shaft is above 7 μm. It can be concluded that the micro-coupling successfully accommodates misalignment errors of the prototype micro-spindle. This research proposes a micro-coupling which is featured with an SMA ring, and it is designed to clamp two shafts, and has smooth transmission, simple assembly, compact structure, zero-maintenance and
Approximations for strongly-coupled supersymmetric quantum mechanics
Kabat, D; Kabat, Daniel; Lifschytz, Gilad
2000-01-01
We advocate a set of approximations for studying the finite temperature behavior of strongly-coupled theories in 0+1 dimensions. The approximation consists of expanding about a Gaussian action, with the width of the Gaussian determined by a set of gap equations. The approximation can be applied to supersymmetric systems, provided that the gap equations are formulated in superspace. It can be applied to large-N theories, by keeping just the planar contribution to the gap equations. We analyze several models of scalar supersymmetric quantum mechanics, and show that the Gaussian approximation correctly distinguishes between a moduli space, mass gap, and supersymmetry breaking at strong coupling. Then we apply the approximation to a bosonic large-N gauge theory, and argue that a Gross-Witten transition separates the weak-coupling and strong-coupling regimes. A similar transition should occur in a generic large-N gauge theory, in particular in 0-brane quantum mechanics.
Wang, Zheng; Liu, Chao; Li, Erwen; Chakravarty, Swapnajit; Xu, Xiaochuan; Wang, Alan X.; Fan, D. L.; Chen, Ray T.
2017-02-01
Raman scattering spectroscopy is a unique tool to probe vibrational, rotational, and other low-frequency modes of a molecular system and therefore could be utilized to identify chemistry and quantity of molecules. However, the ultralow efficient Raman scattering, which is only 1/109 1/1014 of the excitation light due to the small Raman scattering cross-sections of molecules, have significantly hindered its development in practical sensing applications. The discovery of surface-enhanced Raman scattering (SERS) in the 1970s and the significant progress in nanofabrication technique, provide a promising solution to overcome the inherent issues of Raman spectroscopy. It is found that In the vicinity of nanoparticles and their junctions, the Raman signals of molecules can be significantly improved by an enhancement factor as high as 1010, due to the ultrahigh electric field generated by the localized surface plasmons resonance (LSPR), where the intensity of Raman scattering is proportional to the |E|4. In this work, we propose and demonstrate a new approach combining LSPR from nanocapsules with densely assembled silver nanoparticles (NC-AgNPs) and guidemode- resonance (GMR) from dielectric photonic crystal slabs (PCSs) for SERS substrates with robustly high performance.
Simoes, F.; Pfaff, R. F.; Freudenreich, H.; Klenzing, J.; Rowland, D. E.
2012-12-01
Detection of Schumann Resonance spectral features of the earth-ionosphere cavity from outside the cavity offers new remote sensing capabilities to assess tropospheric-space weather connections, namely periodic patterns observed in tropospheric, ionospheric, and magnetospheric data. Semiannual oscillations have been identified in a variety of hydrodynamic and electrodynamic processes, but the mechanism (or mechanisms) responsible for such effect remains elusive. Analysis of AC electric field measurements made by the Vector Electric Field Instrument (VEFI) on board the Communications/Navigation Outage Forecasting System (C/NOFS) satellite also shows a semiannual pattern in Schumann resonance data recorded during nighttime in the equatorial ionosphere. In this work we present C/NOFS data and outline future developments involving low frequency electric and magnetic field measurements. We discuss how patterns observed in the Schumann resonance amplitude are expected to contribute to validate - or at least constrain - mechanisms previously proposed to explain the semiannual oscillation, as well as their implications for investigating coupling between layers of the Earth gaseous envelope.
Fu, J C; Chen, C C; Chai, J W; Wong, S T C; Li, I C
2010-06-01
We propose an automatic hybrid image segmentation model that integrates the statistical expectation maximization (EM) model and the spatial pulse coupled neural network (PCNN) for brain magnetic resonance imaging (MRI) segmentation. In addition, an adaptive mechanism is developed to fine tune the PCNN parameters. The EM model serves two functions: evaluation of the PCNN image segmentation and adaptive adjustment of the PCNN parameters for optimal segmentation. To evaluate the performance of the adaptive EM-PCNN, we use it to segment MR brain image into gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF). The performance of the adaptive EM-PCNN is compared with that of the non-adaptive EM-PCNN, EM, and Bias Corrected Fuzzy C-Means (BCFCM) algorithms. The result is four sets of boundaries for the GM and the brain parenchyma (GM+WM), the two regions of most interest in medical research and clinical applications. Each set of boundaries is compared with the golden standard to evaluate the segmentation performance. The adaptive EM-PCNN significantly outperforms the non-adaptive EM-PCNN, EM, and BCFCM algorithms in gray mater segmentation. In brain parenchyma segmentation, the adaptive EM-PCNN significantly outperforms the BCFCM only. However, the adaptive EM-PCNN is better than the non-adaptive EM-PCNN and EM on average. We conclude that of the three approaches, the adaptive EM-PCNN yields the best results for gray matter and brain parenchyma segmentation.
Mechanical filtering in forced-oscillation of two coupled pendulums
Foulaadvand, M Ebrahim
2010-01-01
Forced oscillation of a system composed of two pendulums coupled by a spring in the presence of damping is investigated. In the steady state and within the small angle approximation we solve the system equations of motion and obtain the amplitudes and phases of in terms of the frequency of the sinusoidal driving force. The resonance frequencies are obtained and the amplitude ratio is discussed in details. Contrary to a single oscillator, in this two-degree of freedom system four resonant frequencies, which are close to mode frequencies, appear. Within the pass-band interval the system is shown to exhibit a rich and complicated behaviour. It is shown that damping crucially affects the system properties. Under certain circumstances, the amplitude of the oscillator which is directly connected to the driving force becomes smaller than the one far from it. Particularly we show the existence of a driving frequency at which the connected oscillator's amplitude goes zero.
Britzger, Michael; Wimmer, Maximilian H; Khalaidovski, Alexander; Friedrich, Daniel; Kroker, Stefanie; Brückner, Frank; Kley, Ernst-Bernhard; Tünnermann, Andreas; Danzmann, Karsten; Schnabel, Roman
2012-11-05
Michelson-type laser-interferometric gravitational-wave (GW) observatories employ very high light powers as well as transmissively-coupled Fabry-Perot arm resonators in order to realize high measurement sensitivities. Due to the absorption in the transmissive optics, high powers lead to thermal lensing and hence to thermal distortions of the laser beam profile, which sets a limit on the maximal light power employable in GW observatories. Here, we propose and realize a Michelson-type laser interferometer with arm resonators whose coupling components are all-reflective second-order Littrow gratings. In principle such gratings allow high finesse values of the resonators but avoid bulk transmission of the laser light and thus the corresponding thermal beam distortion. The gratings used have three diffraction orders, which leads to the creation of a second signal port. We theoretically analyze the signal response of the proposed topology and show that it is equivalent to a conventional Michelson-type interferometer. In our proof-of-principle experiment we generated phase-modulation signals inside the arm resonators and detected them simultaneously at the two signal ports. The sum signal was shown to be equivalent to a single-output-port Michelson interferometer with transmissively-coupled arm cavities, taking into account optical loss. The proposed and demonstrated topology is a possible approach for future all-reflective GW observatory designs.
Karna, Sanjay; Mahat, Meg; Choi, Tae-Youl; Shimada, Ryoko; Wang, Zhiming; Neogi, Arup
2016-11-01
The light emission from reduced graphene oxide quantum dots (rGO-QDs) exhibit a significant enhancement in photoluminescence (PL) due to localized surface plasmon (LSP) interactions. Silver and gold nanoparticles (NPs) coupled to rGO nanoparticles exhibit the effect of resonant LSP coupling on the emission processes. Enhancement of the radiative recombination rate in the presence of Ag-NPs induced LSP tuned to the emission energy results in a four-fold increase in PL intensity. The localized field due to the resonantly coupled LSP modes induces n-π* transitions that are not observed in the absence of the resonant interaction of the plasmons with the excitons. An increase in the density of the Ag-NPs result in a detuning of the LSP energy from the emission energy of the nanoparticles. The detuning is due to the cumulative effect of the red-shift in the LSP energy and the electrostatic field induced blue shift in the PL energy of the rGO-QDs. The detuning quenches the PL emission from rGO-QDs at higher concentration of Ag NPs due to non-dissipative effects unlike plasmon induced Joule heating that occurs under resonance conditions. An increase in Au nanoparticles concentration results in an enhancement of PL emission due to electrostatic image charge effect.
Karna, Sanjay; Mahat, Meg; Choi, Tae-Youl; Shimada, Ryoko; Wang, Zhiming; Neogi, Arup
2016-11-22
The light emission from reduced graphene oxide quantum dots (rGO-QDs) exhibit a significant enhancement in photoluminescence (PL) due to localized surface plasmon (LSP) interactions. Silver and gold nanoparticles (NPs) coupled to rGO nanoparticles exhibit the effect of resonant LSP coupling on the emission processes. Enhancement of the radiative recombination rate in the presence of Ag-NPs induced LSP tuned to the emission energy results in a four-fold increase in PL intensity. The localized field due to the resonantly coupled LSP modes induces n-π* transitions that are not observed in the absence of the resonant interaction of the plasmons with the excitons. An increase in the density of the Ag-NPs result in a detuning of the LSP energy from the emission energy of the nanoparticles. The detuning is due to the cumulative effect of the red-shift in the LSP energy and the electrostatic field induced blue shift in the PL energy of the rGO-QDs. The detuning quenches the PL emission from rGO-QDs at higher concentration of Ag NPs due to non-dissipative effects unlike plasmon induced Joule heating that occurs under resonance conditions. An increase in Au nanoparticles concentration results in an enhancement of PL emission due to electrostatic image charge effect.
Towards achieving strong coupling in three-dimensional-cavity with solid state spin resonance
Le Floch, J.-M.; Delhote, N.; Aubourg, M.; Madrangeas, V.; Cros, D.; Castelletto, S.; Tobar, M. E.
2016-04-01
We investigate the microwave magnetic field confinement in several microwave three-dimensional (3D)-cavities, using a 3D finite-element analysis to determine the best design and achieve a strong coupling between microwave resonant cavity photons and solid state spins. Specifically, we design cavities for achieving strong coupling of electromagnetic modes with an ensemble of nitrogen vacancy (NV) defects in diamond. We report here a novel and practical cavity design with a magnetic filling factor of up to 4 times (2 times higher collective coupling) than previously achieved using one-dimensional superconducting cavities with a small mode volume. In addition, we show that by using a double-split resonator cavity, it is possible to achieve up to 200 times better cooperative factor than the currently demonstrated with NV in diamond. These designs open up further opportunities for studying strong and ultra-strong coupling effects on spins in solids using alternative systems with a wider range of design parameters. The strong coupling of paramagnetic spin defects with a photonic cavity is used in quantum computer architecture, to interface electrons spins with photons, facilitating their read-out and processing of quantum information. To achieve this, the combination of collective coupling of spins and cavity mode is more feasible and offers a promising method. This is a relevant milestone to develop advanced quantum technology and to test fundamental physics principles.
Modeling Chemical Mechanical Polishing with Couple Stress Fluids
张朝辉; 雒建斌; 温诗铸
2004-01-01
Chemical mechanical polishing (CMP) is a manufacturing process used to achieve high levels of global and local planarity.Currently, the slurries used in CMP usually contain nanoscale particles to accelerate the removal ratio and to optimize the planarity, whose rheological properties can no longer be accurately modeled with Newtonian fluids.The Reynolds equation, including the couple stress effects, was derived in this paper.The equation describes the mechanism to solve the CMP lubrication equation with the couple stress effects.The effects on load and moments resulting from the various parameters, such as pivot height, roll angle, and pitch angle, were subsequently simulated.The results show that the couple stress can provide higher load and angular moments.This study sheds some lights into the mechanism of the CMP process.
Analysis and Optimization of Four-Coil Planar Magnetically Coupled Printed Spiral Resonators
Sadeque Reza Khan
2016-08-01
Full Text Available High-efficiency power transfer at a long distance can be efficiently established using resonance-based wireless techniques. In contrast to the conventional two-coil-based inductive links, this paper presents a magnetically coupled fully planar four-coil printed spiral resonator-based wireless power-transfer system that compensates the adverse effect of low coupling and improves efficiency by using high quality-factor coils. A conformal architecture is adopted to reduce the transmitter and receiver sizes. Both square architecture and circular architectures are analyzed and optimized to provide maximum efficiency at a certain operating distance. Furthermore, their performance is compared on the basis of the power-transfer efficiency and power delivered to the load. Square resonators can produce higher measured power-transfer efficiency (79.8% than circular resonators (78.43% when the distance between the transmitter and receiver coils is 10 mm of air medium at a resonant frequency of 13.56 MHz. On the other hand, circular coils can deliver higher power (443.5 mW to the load than the square coils (396 mW under the same medium properties. The performance of the proposed structures is investigated by simulation using a three-layer human-tissue medium and by experimentation.
Superconducting Resonator-Rydberg Atom Hybrid in the Strong Coupling Regime
Yu, Deshui; Valado, Maria Martinez; Hufnagel, Christoph; Kwek, Leong Chuan; Amico, Luigi; Dumke, Rainer
2016-01-01
We propose a promising hybrid quantum system, where a highly-excited atom strongly interacts with a superconducting LC oscillator via the electric field of capacitor. An external electrostatic field is applied to tune the energy spectrum of atom. The atomic qubit is implemented by two eigenstates near an avoided-level crossing in the DC Stark map of Rydberg atom. Varying the electrostatic field brings the atomic-qubit transition on- or off-resonance to the microwave resonator, leading to a strong atom-resonator coupling with an extremely large cooperativity. Like the nonlinearity induced by Josephson junctions in superconducting circuits, the large atom-resonator interface disturbs the harmonic potential of resonator, resulting in an artificial two-level particle. Different universal two-qubit logic gates can also be performed on our hybrid system within the space where an atomic qubit couples to a single photon with an interaction strength much larger than any relaxation rates, opening the door to the cavity...
Superconducting resonator and Rydberg atom hybrid system in the strong coupling regime
Yu, Deshui; Landra, Alessandro; Valado, María Martínez; Hufnagel, Christoph; Kwek, Leong Chuan; Amico, Luigi; Dumke, Rainer
2016-12-01
We propose a promising hybrid quantum system, where a highly excited atom strongly interacts with a superconducting L C oscillator via the electric field of capacitor. An external electrostatic field is applied to tune the energy spectrum of the atom. The atomic qubit is implemented by two eigenstates near an avoided-level crossing in the dc Stark map of a Rydberg atom. Varying the electrostatic field brings the atomic-qubit transition on or off resonance with respect to the microwave resonator, leading to a strong atom-resonator coupling with an extremely large cooperativity. Like the nonlinearity induced by Josephson junctions in superconducting circuits, the large atom-resonator interface disturbs the harmonic potential of the resonator, resulting in an artificial two-level particle. Different universal two-qubit logic gates can also be performed on our hybrid system within the space where an atomic qubit couples to a single photon with an interaction strength much larger than any relaxation rates, opening the door to the cavity-mediated state transmission.
A Cylindrical Dielectric Resonator Antenna-Coupled Sensor Configuration for 94 GHz Detection
M. Kamran Saleem
2014-01-01
Full Text Available A novel antenna-coupled sensor configuration for millimeter wave detection is presented. The antenna is based on two cylindrical dielectric resonators (CDRs excited by rectangular slots placed below the CDRs. The HEM11Δ mode resonating at 94 GHz is generated within the CDRs and a 3 GHz impedance bandwidth is achieved at center frequency of 94 GHz. The simulated antenna gain is 7.8 dB, with a radiation efficiency of about 40%.
Matsuda, Nobuyuki; Shimizu, Kaoru; Tokura, Yasuhiro; Kuramochi, Eiichi; Notomi, Masaya; 10.1364/OE.21.008596
2013-01-01
We demonstrate the generation of quantum-correlated photon pairs from a Si photonic-crystal coupled-resonator optical waveguide. A slow-light supermode realized by the collective resonance of high-Q and small-mode-volume photonic-crystal cavities successfully enhanced the efficiency of the spontaneous four-wave mixing process. The generation rate of photon pairs was improved by two orders of magnitude compared with that of a photonic-crystal line defect waveguide without a slow-light effect.
Matsuda, Nobuyuki; Takesue, Hiroki; Shimizu, Kaoru; Tokura, Yasuhiro; Kuramochi, Eiichi; Notomi, Masaya
2013-04-08
We demonstrate the generation of quantum-correlated photon pairs from a Si photonic-crystal coupled-resonator optical waveguide. A slow-light supermode realized by the collective resonance of high-Q and small-mode-volume photonic-crystal cavities successfully enhanced the efficiency of the spontaneous four-wave mixing process. The generation rate of photon pairs was improved by two orders of magnitude compared with that of a photonic-crystal line defect waveguide without a slow-light effect.
Yang, Bo; Zhang, Xiao; Zhang, Lu; Luo, Mao-Kang
2016-08-01
The long-time collective behavior of globally coupled Langevin equations in a dichotomous fluctuating potential driven by a periodic source is investigated. By describing the collective behavior using the moments of the mean field and single-particle displacements, we study stochastic resonance and synchronization using the exact steady-state solutions and related stability criteria. Based on the simulation results and the criterion of the stationary regime, the notable differences between the stationary and nonstationary regimes are demonstrated. For the stationary regime, stochastic resonance with synchronization is discussed, and for the nonstationary regime, the volatility clustering phenomenon is observed.
Grating-coupled surface plasmon resonance in conical mounting with polarization modulation.
Ruffato, G; Romanato, F
2012-07-01
A grating-coupled surface plasmon resonance (GCSPR) technique based on polarization modulation in conical mounting is presented. A metallic grating is azimuthally rotated to support double-surface plasmon polariton excitation and exploit the consequent sensitivity enhancement. Corresponding to the resonance polar angle, a polarization scan of incident light is performed, and reflectivity data are collected before and after functionalization with a dodecanethiol self-assembled monolayer. The output signal exhibits a harmonic dependence on polarization, and the phase term is used as a parameter for sensing. This technique offers the possibility of designing extremely compact, fast, and cheap high-resolution plasmonic sensors based on GCSPR.
Ling, Wen; Jerschow, Alexej
2007-02-14
Of the various ways in which nuclear spin systems can relax to their ground states, the processes involving an interference between different relaxation mechanisms, such as dipole-dipole coupling and chemical shift anisotropy, have become of great interest lately. The authors show here that the interference between the quadrupolar coupling and the paramagnetic interaction (cross-correlated relaxation) gives rise to nuclear spin transitions that would remain forbidden otherwise. In addition, frequency shifts arise. These would be reminiscent of residual anisotropic interactions when there are none. While interesting from a fundamental point of view, these processes may become relevant in magnetic resonance imaging experiments which involve quadrupolar spins, such as (23)Na, in the presence of contrast agents. Geometrical constraints in paramagnetic molecule structures may likewise be derived from these interference effects.
Electromagnetic interactions in a pair of coupled split-ring resonators
Seetharaman, S. S.; King, C. G.; Hooper, I. R.; Barnes, W. L.
2017-08-01
Split-ring resonators (SRRs) are a fundamental building block of many electromagnetic metamaterials. Typically the response of a metamaterial is assumed to be independent of interelement interactions in the material. We show that SRRs in close proximity to each other exhibit a rich coupling that involves both electric and magnetic interactions. We study experimentally and computationally the strength and nature of the coupling between two identical SRRs as a function of their separation and relative orientation. We characterize the electric and magnetic couplings and find that, when SRRs are close enough to be in each other's near field, the electric and magnetic couplings may either reinforce each other or act in opposition. At larger separations retardation effects become important.
King, Jonathan P; Blanchard, John W
2016-01-01
Here we demonstrate that a term in the nuclear spin Hamiltonian, the antisymmetric \\textit{J}-coupling, is fundamentally connected to molecular chirality. We propose and simulate a nuclear magnetic resonance (NMR) experiment to observe this interaction and differentiate between enantiomers without adding any additional chiral agent to the sample. The antisymmetric \\textit{J}-coupling may be observed in the presence of molecular orientation by an external electric field. The opposite parity of the antisymmetric coupling tensor and the molecular electric dipole moment yields a sign change of the observed coupling between enantiomers. We show how this sign change influences the phase of the NMR spectrum and may be used to discriminate between enantiomers.
Angerer, Andreas, E-mail: andreas.angerer@tuwien.ac.at; Astner, Thomas; Wirtitsch, Daniel; Majer, Johannes, E-mail: johannes.majer@tuwien.ac.at [Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna (Austria); Sumiya, Hitoshi [Sumitomo Electric Industries Ltd., Itami 664-001 (Japan); Onoda, Shinobu [Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Isoya, Junichi [Research Centre for Knowledge Communities, University of Tsukuba, 1-2 Kasuga, Tsukuba, Ibaraki 305-8550 (Japan); Putz, Stefan [Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna (Austria); Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)
2016-07-18
We design and implement 3D-lumped element microwave cavities that spatially focus magnetic fields to a small mode volume. They allow coherent and uniform coupling to electron spins hosted by nitrogen vacancy centers in diamond. We achieve large homogeneous single spin coupling rates, with an enhancement of more than one order of magnitude compared to standard 3D cavities with a fundamental resonance at 3 GHz. Finite element simulations confirm that the magnetic field distribution is homogeneous throughout the entire sample volume, with a root mean square deviation of 1.54%. With a sample containing 10{sup 17} nitrogen vacancy electron spins, we achieve a collective coupling strength of Ω = 12 MHz, a cooperativity factor C = 27, and clearly enter the strong coupling regime. This allows to interface a macroscopic spin ensemble with microwave circuits, and the homogeneous Rabi frequency paves the way to manipulate the full ensemble population in a coherent way.
Real-time Measurement of Mechanical Fluctuations in Carbon Nanotube Resonators
Tsioutsios, Ioannis; Tavernarakis, Alexandros; Osmond, Johann; Verlot, Pierre; Bachtold, Adrian
Carbon nanotube resonators have been recently shown to hold an exceptional sensing potential, relying on their extremely low mass. As a consequence, they are also expected to transduce the fundamental thermal force into very large motion fluctuations. Recently, an increasing number of theoretical proposals have suggested that this property may strongly affect the vibrational behaviour of carbon nanotube resonators, which has so far remained unobserved. Here we report the first, real-time detection of the thermally-induced vibrations in carbon nanotube resonators with masses in the 10 ag range. We show that coupling singly-clamped carbon nanotubes to a focused electron beam enables the full access to their mechanical trajectories. Our detailed analysis demonstrates that our devices behave as linear harmonic oscillators undergoing thermally-driven Brownian motion. Our result establish the viability of carbon nanotube resonator technology at room temperature and paves the way towards the observing novel thermodynamics regimes in nanomechanics. ICFO, Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona, Spain.
Gambarota, Giulio
2016-09-03
Magnetic resonance spectroscopy (MRS) is a well established modality for investigating tissue metabolism in vivo. In recent years, many efforts by the scientific community have been directed towards the improvement of metabolite detection and quantitation. Quantum mechanics simulations allow for investigations of the MR signal behaviour of metabolites; thus, they provide an essential tool in the optimization of metabolite detection. In this review, we will examine quantum mechanics simulations based on the density matrix formalism. The density matrix was introduced by von Neumann in 1927 to take into account statistical effects within the theory of quantum mechanics. We will discuss the main steps of the density matrix simulation of an arbitrary spin system and show some examples for the strongly coupled two spin system.
Fluid coupling in a discrete model of cochlear mechanics.
Elliott, Stephen J; Lineton, Ben; Ni, Guangjian
2011-09-01
A discrete model of cochlear mechanics is introduced that includes a full, three-dimensional, description of fluid coupling. This formulation allows the fluid coupling and basilar membrane dynamics to be analyzed separately and then coupled together with a simple piece of linear algebra. The fluid coupling is initially analyzed using a wavenumber formulation and is separated into one component due to one-dimensional fluid coupling and one comprising all the other contributions. Using the theory of acoustic waves in a duct, however, these two components of the pressure can also be associated with a far field, due to the plane wave, and a near field, due to the evanescent, higher order, modes. The near field components are then seen as one of a number of sources of additional longitudinal coupling in the cochlea. The effects of non-uniformity and asymmetry in the fluid chamber areas can also be taken into account, to predict both the pressure difference between the chambers and the mean pressure. This allows the calculation, for example, of the effect of a short cochlear implant on the coupled response of the cochlea.
Intense energy transfer and superharmonic resonance in a system of two coupled oscillators.
Kovaleva, Agnessa; Manevitch, Leonid; Manevitch, Elina
2010-05-01
The paper presents the analytic study of energy exchange in a system of coupled nonlinear oscillators subject to superharmonic resonance. The attention is given to complete irreversible energy transfer that occurs in a system with definite initial conditions corresponding to a so-called limiting phase trajectory (LPT). We show that the energy imparted in the system is partitioned among the principal and superharmonic modes but energy exchange can be due to superharmonic oscillations. Using the LPT concept, we construct approximate analytic solutions describing intense irreversible energy transfer in a harmonically excited Duffing oscillator and a system of two nonlinearly coupled oscillators. Numerical simulations confirm the accuracy of the analytic approximations.
Numerical simulation study on spin resonant depolarization due to spin-orbit coupling
Lan Jie-Qin; Xu Hong-Liang
2012-01-01
The spin polarization phenomenon in lepton circular accelerators had been known for many years.It provides a new approach for physicists to study the spin feature of fundamental particles and the dynamics of spin-orbit coupling,such as spin resonances.We use numerical simulation to study the features of spin under the modulation of orbital motion in an electron storage ring.The various cases of depolarization due to spin-orbit coupling through an emitting photon and misalignment of magnets in the ring are discussed.
Asano, Motoki; Özdemir, Şahin Kaya; Ikuta, Rikizo; Yang, Lan; Imoto, Nobuyuki; Yamamoto, Takashi
2016-01-01
We report the first observation of stimulated Brillouin scattering (SBS) with Brillouin lasing, and Brillouin-coupled four-wave-mixing (FWM) in an ultra-high-Q silica microbottle resonator. The Brillouin lasing was observed at the frequency of $\\Omega_B=2\\pi\\times10.4$ GHz with a threshold power of $0.45$ mW. Coupling between Brillouin and FWM was observed in both backward and forward scattering directions with separations of $2\\Omega_B$. At a pump power of $10$ mW, FWM spacing reached to 7th and 9th order anti-Stokes and Stokes, respectively.
Asano, Motoki; Takeuchi, Yuki; Ozdemir, Sahin Kaya; Ikuta, Rikizo; Yang, Lan; Imoto, Nobuyuki; Yamamoto, Takashi
2016-05-30
We report the first observation of stimulated Brillouin scattering (SBS) with Brillouin lasing, and Brillouin-coupled four-wave-mixing (FWM) in an ultra-high-Q silica microbottle resonator. The Brillouin lasing was observed at the frequency of ΩB = 2π × 10.4 GHz with a threshold power of 0.45 mW. Coupling between Brillouin and FWM was observed in both backward and forward scattering directions with separations of 2ΩB. At a pump power of 10 mW, FWM spacing reached to 7th and 9th order anti-Stokes and Stokes, respectively.
Chen, Xiumei; Yan, Xiaopeng; Li, Ping; Mou, Yongni; Wang, Wenqiang; Guan, Zhiqiang; Xu, Hongxing
2016-08-22
The mechanism of resonant perfect optical absorbers is quantitatively revealed by the coupled mode method for the air/grating/dielectric film/air four region system. The sufficient and necessary conditions of the perfect optical absorption are derived from the interface scattering coefficients analyses. The coupling of the Fabry-Perot modes in the grating slits and non-zero order quasi waveguide modes in the dielectric film play a key role for the perfect optical absorption when the light is incident from the grating side. The analytical sufficient and necessary conditions of the perfect optical absorption provide an efficient tool towards geometry design for the perfect optical absorption at the specific wavelengths. The advantages of a widely tunable perfect optical absorption wavelength, a high Q factor and the confined energy loss on metal surfaces make the air/grating/film/air structures promising for applications in sensing, modulation and detection.
The Influence of Mechanical Resonance & Compensation Method in CNC Heavy Cutting
WU Yuguo; HUANG Yunlin; SONG Chongzhi
2006-01-01
In CNC heavy cutting servo system, mechanical driving system has a torture feedback on electrical speed-adjustment system, thus it's possible to generate the mechanical resonance. The mechanical resonance makes the feature parameters of mechanical driving system influence the dynamic performance of the electrical speed-adjustment system. This paper has studied the resistance ratio of ζmech and q parameters ,and put forward the compensation method to decrease the mechanical resonance influence.
Microwave power coupling with electron cyclotron resonance plasma using Langmuir probe
S K Jain; V K Senecha; P A Naik; P R Hannurkar; S C Joshi
2013-07-01
Electron cyclotron resonance (ECR) plasma was produced at 2.45 GHz using 200 – 750 W microwave power. The plasma was produced from argon gas at a pressure of 2 × 10−4 mbar. Three water-cooled solenoid coils were used to satisfy the ECR resonant conditions inside the plasma chamber. The basic parameters of plasma, such as electron density, electron temperature, floating potential, and plasma potential, were evaluated using the current–voltage curve using a Langmuir probe. The effect of microwave power coupling to the plasma was studied by varying the microwave power. It was observed that the optimum coupling to the plasma was obtained for ∼ 600 W microwave power with an average electron density of ∼ 6 × 1011 cm−3 and average electron temperature of ∼ 9 eV.
Permanent matching of coupled optical bottle resonators with better than 0.16 GHz precision
Toropov, N A
2016-01-01
The fabrication precision is one of the most critical challenges on the way to the creation of practical photonic circuits composed of coupled high Q-factor microresonators. While very accurate transient tuning of microresonators based on local heating has been reported, the record precision of permanent resonance positioning achieved by post-processing is still within 1-5 GHz. Here we demonstrate two coupled bottle microresonators fabricated at the fiber surface which resonances are matched with a better than 0.16 GHz precision. This corresponds to a better than 0.17 angstrom precision in the effective fiber radius variation. The achieved fabrication precision is only limited by the resolution of our optical spectrum analyzer and can be potentially improved by an order of magnitude.
Coherence resonance in globally coupled neuronal networks with different neuron numbers
Ning Wei-Lian; Zhang Zheng-Zhen; Zeng Shang-You; Luo Xiao-Shu; Hu Jin-Lin; Zeng Shao-Wen; Qiu Yi; Wu Hui-Si
2012-01-01
Because a brain consists of tremendous neuronal networks with different neuron numbers ranging from tens to tens of thousands,we study the coherence resonance due to ion channel noises in globally coupled neuronal networks with different neuron numbers.We confirm that for all neuronal networks with different neuron numbers there exist the array enhanced coherence resonance and the optimal synaptic conductance to cause the maximal spiking coherence.Furthermoremore,the enhancement effects of coupling on spiking coherence and on optimal synaptic conductance are almost the same,regardless of the neuron numbers in the neuronal networks.Therefore for all the neuronal networks with different neuron numbers in the brain,relative weak synaptic conductance (0.1 mS/cm2) is sufficient to induce the maximal spiking coherence and the best sub-threshold signal encoding.
Topological phononic states of underwater sound based on coupled ring resonators
He, Cheng; Li, Zheng; Ni, Xu; Sun, Xiao-Chen; Yu, Si-Yuan [National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China); Lu, Ming-Hui, E-mail: luminghui@nju.edu.cn; Liu, Xiao-Ping; Chen, Yan-Feng [National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)
2016-01-18
We report a design of topological phononic states for underwater sound using arrays of acoustic coupled ring resonators. In each individual ring resonator, two degenerate acoustic modes, corresponding to clockwise and counter-clockwise propagation, are treated as opposite pseudospins. The gapless edge states arise in the bandgap resulting in protected pseudospin-dependent sound transportation, which is a phononic analogue of the quantum spin Hall effect. We also investigate the robustness of the topological sound state, suggesting that the observed pseudospin-dependent sound transportation remains unless the introduced defects facilitate coupling between the clockwise and counter-clockwise modes (in other words, the original mode degeneracy is broken). The topological engineering of sound transportation will certainly promise unique design for next generation of acoustic devices in sound guiding and switching, especially for underwater acoustic devices.
Ferromagnetic resonance in coupled permalloy double films separated by a Cu interlayer
Maksymowicz, A. Z.; Whiting, J. S. S.; Watson, M. L.; Chambers, A.
1991-03-01
Ferromagnetic resonance (FMR) at 16 GHz was used to study the magnetic coupling between two-layers of permalloy separated by a nonmagnetic Cu layer. Samples with the same thickness (600 Å) of both permalloy layers were deposited from e-gun sources onto glass substrates in UHV. The thickness d of the Cu interlayer was varied from 5 to 37 Å. The exchange coupling energy ( E = - KM1· M2) model was used to describe the interaction between the two magnetic layers. It was found from the ferromagnetic resonance data in the perpendicular configuration that K( d) follows an exponential law, K = K0e - d/ q, where q = 9.3 Å.
Resonant optimization in the mechanical unzipping of DNA
Bergues-Pupo, Ana Elisa; Falo, Fernando; Fiasconaro, Alessandro
2014-03-01
The mechanical separation of the double-stranded DNA in single-molecule experiments is of fundamental importance in the understanding of the replication or transcription processes. Time-dependent forces can influence in different ways the dynamics of this separation. We study here this unzipping of DNA in the framework of the mesoscopic Peyrard-Bishop-Dauxois model under the influence of a periodic driving. Two different protocols, both of them feasible experimentally, have been studied under two modes of pulling: controlled force and controlled position. A strong resonant activation phenomenon has been observed in the magnitudes that characterize the mechanical unzipping such as the mean opening time, the mean opening force, and the mean critical opening force, all of them as a function of the frequency of the driving. This optimal frequency region has been observed for all the cases studied both in a uniform DNA of adenine-thymine nucleotides and in a real DNA sequence. Importantly, a well precise resonant frequency can be determined with the use of one of this protocols.
Sensitivity and detection limit of dual-waveguide coupled microring resonator biosensors
Zhixuan Xia; Huaxiang Yi; Yao Chen; Zhiping Zhou
2009-01-01
We show that a linear relation exists between the device sensitivity and the quality (Q) factor of a dual-waveguide coupled microring resonator optical biosensor when the optimal conditions are satisfied. We also show that the detection limit depends on the loss coefficient and signal-to-nosie ratio (SNR) of the overall system, rather than the circumference of the ring. For a microring resonator sensor whose Q factor is 20000, the detection limit is found to be about 10-7 with 30-dB SNR, which is in good agreement with reported experimental data. These results indicate that loss reduction is the top priority in the design and fabrication of highly sensitive microring resonator optical biosensors.
Formation of long-lived resonances in hexagonal cavities by strong coupling of superscar modes
Song, Qinghai; Ge, Li; Wiersig, Jan; Cao, Hui
2013-08-01
The recent progresses in single crystalline wide bandgap hexagonal disk have stimulated intense research attention on pursuing ultraviolet (UV) laser diodes with low thresholds. While whispering-gallery modes based UV lasers have been successfully obtained in GaN, ZnO nanorods, and nanopillars, the reported thresholds are still very high, due to the low-quality (Q) factors of the hexagonal resonances. Here we demonstrate resonances whose Q factors can be more than two orders of magnitude higher than the hexagonal modes, promising the reduction of the energy consumption. The key to our finding is the avoided resonance crossing between superscar states along two sets of nearly degenerated triangle orbits, which leads to the formation of hexagram modes. The mode couplings suppress the field distributions at the corners and the deviations from triangle orbits simultaneously and therefore enhance the Q factors significantly.
Searches for new resonances with couplings to third generation quarks with the CMS detector
Haller, Johannes
2017-01-01
Many models of physics beyond the Standard Model (SM) feature the existence of new particle states with enhanced couplings to quarks of the third generation. In run-2 of the LHC, the high centre-of-mass energy ($\\sqrt{s}$) of $pp$ collisions enables searches for theses new states up to mass regions not accessible before. For the identification of the boosted decay products powerful new reconstruction tools have been developed using e.g. the substructure of hadronic jets or dedicated lepton-isolation requirements. In this article an overview is presented of searches for new resonances decaying to top quarks as performed by the CMS collaboration in data collected during the years 2015 and 2016 at $\\sqrt{s}=13$\\,TeV. This includes searches for $t\\bar{t}$ and $tb$ resonances, resonances with decays to a SM top quark and a vector-like $T$ quark, as well as excited top quarks.
Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances
Thompson, I J [Lawrence Livermore National Laboratory (LLNL); Escher, Jutta E [ORNL; Arbanas, Goran [ORNL
2013-01-01
Semidirect capture, a two-step process that excites a giant-dipole resonance followed by its radiative de-excitation, is a dominant process near giant-dipole resonances, that is, for incoming neutron energies within 5 20 MeV. At lower energies such processes may affect neutron capture rates that are relevant to astrophysical nucleosynthesis models. We implement a semidirect capture model in the coupled-channel reaction code Fresco and validate it by comparing the cross section for direct-semidirect capture 208Pb(n,g)209Pb to experimental data. We also investigate the effect of low-energy electric dipole strength in the pygmy resonance. We use a conventional single-particle direct-semidirect capture code Cupido for comparison. Furthermore, we present and discuss our results for direct-semidirect capture reaction 130Sn(n,g)131Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.
CHAN DU
2014-01-01
Full Text Available We developed a biosensor that is capable for simultaneous surface plasmon resonance (SPR sensing and hyperspectral fluorescence analysis in this paper. A symmetrical metal-dielectric slab scheme is employed for the excitation of coupled plasmon waveguide resonance (CPWR in the present work. Resonance between surface plasmon mode and the guided waveguide mode generates narrower full width half-maximum of the reflective curves which leads to increased precision for the determination of refractive index over conventional SPR sensors. In addition, CPWR also offers longer surface propagation depths and higher surface electric field strengths that enable the excitation of fluorescence with hyperspectral technique to maintain an appreciable signal-to-noise ratio. The refractive index information obtained from SPR sensing and the chemical properties obtained through hyperspectral fluorescence analysis confirm each other to exclude false-positive or false-negative cases. The sensor provides a comprehensive understanding of the biological events on the sensor chips.
Fauché, Pierre; Kosionis, Spyridon G.; Lalanne, Philippe
2017-05-01
There is considerable interest in collective effects in hybrid systems formed by molecular or atomic ensembles strongly coupled by an electromagnetic resonance. For analyzing such collective effects, we develop an efficient and general theoretical formalism based on the natural modes of the resonator. The main strength of our approach is its generality and the high level of analyticity enabled by modal analysis, which allows one to model complex hybrid systems without any restriction on the resonator shapes or material properties, and to perform statistical computations to predict general properties that are robust to spatial and polarization disorders. Most notably, we establish that super-radiant modes remain even after ensemble averaging and act as an "invisibility cloak" with a spectral bandwidth that scales with the number of oscillators and the spatially averaged Purcell factor.
Cross-polarization coupling and switching in an open nano-meta-resonator
Szabelak, W.; Nasalski, W.
2011-11-01
We demonstrate the reconfiguration process of optical beam fields circulating in an open nano-meta-resonator cavity. The cavity is composed of four corners or quadrants of space filled alternatively with dielectric and metamaterial media. The media are assumed to be lossless, nondispersive and of parameters precluding impedance matching at the boundaries between the subsequent corners. Beam path retracement in the cavity is obtained from a resonance condition of phase compensation along each optical ray contributed to the circulating beam. Cross-polarization coupling between TM and TE components of elegant higher-order Hermite-Gaussian beams propagating in the resonator is analysed. The existence of the phenomena of beam excitation, filtering and switching predicted on these grounds is explicitly confirmed by numerical simulations. All phenomena described depend substantially on a field cross-sectional diameter of the circulating beams.
Series-coupled silicon racetrack resonators and the Vernier effect: theory and measurement.
Boeck, Robi; Jaeger, Nicolas A; Rouger, Nicolas; Chrostowski, Lukas
2010-11-22
Silicon-on-insulator racetrack resonators can be used as multiplexers in wavelength division multiplexing applications. The free spectral range should be comparable to the span of the C-band so that a maximum number of channels can be multiplexed. However, the free spectral range is inversely proportional to the length of the resonator and, therefore, bending losses can become non-negligible. A viable alternative to increase the free spectral range is to use the Vernier effect. In this work, we present the theory of series-coupled racetrack resonators exhibiting the Vernier effect. We demonstrate the experimental performance of the device using silicon-on-insulator strip waveguides. The extended free spectral range is 36 nm and the interstitial peak suppression is from 9 dB to 17 dB.
Cascade-coupled racetrack resonators based on the Vernier effect in the mid-infrared.
Troia, Benedetto; Khokhar, Ali Z; Nedeljkovic, Milos; Penades, Jordi Soler; Passaro, Vittorio M N; Mashanovich, Goran Z
2014-10-06
In this paper we report the experimental demonstration of racetrack resonators in silicon-on-insulator technology platform operating in the mid-infrared wavelength range of 3.7-3.8 μm. Insertion loss lower than 1 dB and extinction ratio up to 30 dB were measured for single resonators. The experimental characterization of directional couplers and bending losses in silicon rib waveguides are also reported. Furthermore, we present the design and fabrication of cascade-coupled racetrack resonators based on the Vernier effect. Experimental spectra of Vernier architectures were demonstrated for the first time in the mid-infrared with insertion loss lower than 1 dB and maximum interstitial peak suppression of 10 dB.
Kim, Gun-Duk; Son, Geun-Sik; Lee, Hak-Soon; Kim, Ki-Do; Lee, Sang-Shin
2009-04-01
A refractometric sensor resorting to a vertically coupled polymeric microdisk resonator was demonstrated, estimating the refractive index (RI) of an analyte by monitoring the resonant wavelength shift in its transfer characteristics. The disk resonator was especially overlaid with a high RI TiO2 film, thereby reinforcing the interaction of the evanescent field of its guided mode with the analyte. The sensitivity of the sensor was theoretically and experimentally confirmed to be enhanced by adjusting the overlay thickness. The fabricated sensor provided the maximum sensitivity of approximately 294 nm/RIU (refractive index unit) with the 40-nm-thick overlay, which is equivalent to an improvement of 150% compared with the case without the overlay.
Off-resonance frequency operation for power transfer in a loosely coupled air core transformer
Scudiere, Matthew B
2012-11-13
A power transmission system includes a loosely coupled air core transformer having a resonance frequency determined by a product of inductance and capacitance of a primary circuit including a primary coil. A secondary circuit is configured to have a substantially same product of inductance and capacitance. A back EMF generating device (e.g., a battery), which generates a back EMF with power transfer, is attached to the secondary circuit. Once the load power of the back EMF generating device exceeds a certain threshold level, which depends on the system parameters, the power transfer can be achieved at higher transfer efficiency if performed at an operating frequency less than the resonance frequency, which can be from 50% to 95% of the resonance frequency.
Quantum information transfer with superconducting flux qubits coupled to a resonator
Yang, Chui-Ping
2010-01-01
We propose a way for implementing quantum information transfer with two superconducting flux qubits, by coupling them to a resonator. This proposal does not require adjustment of the level spacings or uniformity in the device parameters. Moreover, neither adiabatic passage nor a second-order detuning is needed by this proposal, thus the operation can be performed much faster when compared with the previous proposals.
Low loss optical waveguide crossing based on octagonal resonant cavity coupling
Mohd. Zahed M. Khan
2009-01-01
A waveguide crossing utilizing a high index contrast material system is presented. The structure is based on coupling with an octagonal resonant cavity inscrted at the waveguide junction. It also employs four identical square metal strips placed at the four comers of the waveguide crossing. The spectral response of the structure calculated using the method of line numerical technique, in general, shows a high power transmission in the forward arm with sufficiently low crosstalk and fraction of radiated power.
Modified SQUID Operator Equation for a Single-Qubit Structure Coupled to a Quantum Resonator
LIANG Bao-Long; WANG Ji-Suo; FAN Hong-Yi; MENG Xiang-Guo
2008-01-01
Role of self-inductance in superconducting quantum interference device (SQUID) charge qubit is considered. It is found that when an SQUID charge qubit is coupled to a quantum LC resonator, the SQUID voltage operator equation is modified in accompanying with the modification of operator Faraday equation describing the inductance. It is shown that when the extra energy is applied to the junction, the mean phase will be squeezed according to a damping factor.
On frequency optimization of assymetric resonant inductive coupling wireless power transfer links
2014-01-01
Resonant Inductive Coupling Wireless Power Transfer (RIC-WPT) is a leading field of research due to the growing number of applications that can benefit from this technology: from biomedical implants to consumer electronics, fractionated spacecraft and electric vehicles amongst others. However, current applications are limited to symetric point-to-point-links. New challenges and applications of RIC-WPT emphasize the necessity to explore, predict and optimize the behavior of these links for dif...
Resonances in coupled {\\pi}K,{\\eta}K scattering from quantum chromodynamics
Dudek, Jozef J; Thomas, Christopher E; Wilson, David J
2014-01-01
Using first-principles calculation within Quantum Chromodynamics, we are able to reproduce the pattern of experimental strange resonances which appear as complex singularities within coupled {\\pi}K, {\\eta}K scattering amplitudes. We make use of numerical computation within the lattice discretized approach to the quantum field theory, extracting the energy dependence of scattering amplitudes through their relationship to the discrete spectrum of the theory in a finite-volume, which we map out in unprecedented detail.
Effects of mode coupling on the admittance of an AT-cut quartz thickness-shear resonator
He Hui-Jing; Yang Jia-Shi; Zhang Wei-Ping; Wang Ji
2013-01-01
We study the effects of couplings to flexure and face-shear modes on the admittance of an AT-cut quartz plate thickness-shear mode resonator.Mindlin's two-dimensional equations for piezoelectric plates are employed.Electrically forced vibration solutions are obtained for three cases:pure thickness-shear mode alone; two coupled modes of thickness shear and flexure; and three coupled modes of thickness shear,flexure,and face shear.Admittance is calculated and its dependence on the driving frequency and the length/thickness ratio of the resonator is examined.Results show that near the thickness-shear resonance,admittance assumes maxima,and that for certain values of the length/thickness ratio,the coupling to flexure causes severe admittance drops,while the coupling to the face-shear mode causes additional admittance changes that were previously unknown and hence are not considered in current resonator design practice.
Coupling of semiconductor carbon nanotubes emission with silicon photonic micro ring resonators
Sarti, Francesco; Caselli, Niccolò; La China, Federico; Biccari, Francesco; Torrini, Ughetta; Intonti, Francesca; Vinattieri, Anna; Durán-Valdeiglesias, Elena; Zhang, Weiwei; Noury, Adrien; Alonso-Ramos, Carlos; Hoang, ThiHong Cam; Serna, Samuel; Le Roux, Xavier; Cassan, Eric; Izard, Nicolas; Yang, Hongliu; Bezugly, Viktor; Cuniberti, Gianaurelio; Filoramo, Arianna; Vivien, Laurent; Gurioli, Massimo
2016-05-01
Hybrid structures are needed to fully exploit the great advantages of Si photonics and several approaches have been addressed where Si devices are bonded to different materials and nanostructures. Here we study the use of semiconductor carbon nanotubes for emission in the 1300 nm wavelength range to functionalize Si photonic structures in view of optoelectronic applications. The Si micro-rings are fully characterized by near field forward resonant scattering with 100 nm resolution. We show that both TE and TM modes can be addressed on the top of the micro-rings in a vectorial imaging of the in-plane polarization components. We coupled the Si micro-resonators with selected carbon nanotubes for high photoluminescence emission. Coupling nanotubes with the evanescent tails in air of the electric field localized in the photonic modes of the micro-resonators is demonstrated by sharp resonances over imposed to the nanotube emission bands. By mapping the Si and the nanotube emission we demonstrate that strong enhancement of the nanotube photoluminescence can be achieved both in the photonic modes of micro-disks and slot micro-rings, whenever the spatial overlap between nano-emitters and photonic modes is fulfilled.
Analysis of electro-optic switches with series-coupled multiple microring resonators
YAN Xin; MA Chun-sheng; ZHENG Chuan-tao; WANG Xian-yin; ZHANG Da-ming
2009-01-01
In terms of the coupled mode theory, microring resonance and electro-optic modulation princeple, a reasonable project is proposed for designing an electro-optic switch with the series-coupled multiple microring resonators. The simulation and optimization are performed at the resonant wavelength of 1550 nm. The results are as follows: the core size of the microring is 1.6 μm×1.6 μm, the confined layer between the core and the electrode is 1.6 μm, the thickness of the electrode is 0.15 μm, the radius ofthe microring is 15.2 μm, the coupling gap between the microring and the channel is 0.14 μm, and the one between the microring and the microring is 0.6 μm, microring number M is 4, the switching voltage is 4 V, the insertion loss is 5.4 dB, and the crosstalk is -20 dB. The output spectrum is much flatter and much steeper than that of the single microring.
Position-dependent coupling between a channel waveguide and a distorted microsphere resonator
Senthil Murugan, Ganapathy; Panitchob, Yuwapat; Tull, Elizabeth J.; Bartlett, Philip N.; Hewak, Daniel W.; Zervas, Michalis N.; Wilkinson, James S.
2010-03-01
Glass microsphere resonators have the potential to add significant functionality to planar lightwave circuits when coupled to waveguides where they can provide wavelength filtering, delay and low-power switching, and laser functions. Design of such photonic circuits requires precise coupling between spheres and waveguides to allow control of Q-factor and hence of stored energy and resonator bandwidth. In this paper an erbium-doped silicate glass microsphere is coupled to an ion-exchanged glass waveguide, and excitation spectra for the sphere whispering-gallery modes are determined as a function of spatial separation. Modal assignment allows extraction of the physical parameters of the microsphere and the dependence of Q-factor with separation is compared with theory. All practical microspheres exhibit a small degree of ellipticity and the effects of this upon whispering-gallery mode excitation and wavelength splitting are explored. It has been shown that appropriate displacement and orientation of slightly deformed microspheres with respect to the waveguide can be used to control the effective Q-factor and optimize the spectral shape of the optical devices. This can result in either single high-Q peaks or substantially broadened and spectrally flattened resonances.
Koide, M. [Department of Science and Technology, Meisei University, Tokyo 191-8656 (Japan)]. E-mail: mkoide@galaxy.ocn.ne.jp; Koike, F. [School of Medicine, Kitasato University, Kanagawa 228-8555 (Japan); Azuma, Y. [PhotonFactory, IMSS, KEK, Ibaraki 305-0801 (Japan); Nagata, T. [Department of Science and Technology, Meisei University, Tokyo 191-8656 (Japan)
2005-06-15
We study the origin of dual window-type 3s->4p photoexcitation resonances of potassium atoms that have been observed previously [M. Koide et al., J. Phys. Soc. Jpn. 71 (2002) 1676] by means of photoion spectroscopy. We also consider the sub-valence shell photoexcitations of other alkali metal atoms. In potassium 3p photoionizations, the photoion energy levels may be labeled by their total angular momenta, and they are well separated due to the spin-orbit couplings in 3p subshells. The system of a photoion and a photoelectron is therefore a superposition of different total spin states if expressed in terms of the LS-coupling scheme. The ionization continuum may couple with several intermediate discrete states with different total spin quantum numbers, giving a possibility to observe split resonance structures in the spectra of 3s->np photoexcitations and in other alkali-atom photoexcitations. We discuss the dual window-type resonances in potassium, rubidium, and cesium atoms.
Olcott, Peter D; Peng, Hao; Levin, Craig S
2009-01-01
A new magnetic resonance imaging (MRI)-compatible positron emission tomography (PET) detector design is being developed that uses electro-optical coupling to bring the amplitude and arrival time information of high-speed PET detector scintillation pulses out of an MRI system. The electro-optical coupling technology consists of a magnetically insensitive photodetector output signal connected to a nonmagnetic vertical cavity surface emitting laser (VCSEL) diode that is coupled to a multimode optical fiber. This scheme essentially acts as an optical wire with no influence on the MRI system. To test the feasibility of this approach, a lutetium-yttrium oxyorthosilicate crystal coupled to a single pixel of a solid-state photomultiplier array was placed in coincidence with a lutetium oxyorthosilicate crystal coupled to a fast photomultiplier tube with both the new nonmagnetic VCSEL coupling and the standard coaxial cable signal transmission scheme. No significant change was observed in 511 keV photopeak energy resolution and coincidence time resolution. This electro-optical coupling technology enables an MRI-compatible PET block detector to have a reduced electromagnetic footprint compared with the signal transmission schemes deployed in the current MRI/PET designs.
Peter D. Olcott
2009-03-01
Full Text Available A new magnetic resonance imaging (MRI-compatible positron emission tomography (PET detector design is being developed that uses electro-optical coupling to bring the amplitude and arrival time information of high-speed PET detector scintillation pulses out of an MRI system. The electro-optical coupling technology consists of a magnetically insensitive photodetector output signal connected to a nonmagnetic vertical cavity surface emitting laser (VCSEL diode that is coupled to a multimode optical fiber. This scheme essentially acts as an optical wire with no influence on the MRI system. To test the feasibility of this approach, a lutetium-yttrium oxyorthosilicate crystal coupled to a single pixel of a solid-state photomultiplier array was placed in coincidence with a lutetium oxyorthosilicate crystal coupled to a fast photomultiplier tube with both the new nonmagnetic VCSEL coupling and the standard coaxial cable signal transmission scheme. No significant change was observed in 511 keV photopeak energy resolution and coincidence time resolution. This electro-optical coupling technology enables an MRI-compatible PET block detector to have a reduced electromagnetic footprint compared with the signal transmission schemes deployed in the current MRI/PET designs.
Zhang, Yumin; Chan, Yum-Ji; Huang, Lixi
2014-05-01
Broadband noise with profound low-frequency profile is prevalent and difficult to be controlled mechanically. This study demonstrates effective broadband sound absorption by reducing the mechanical reactance of a loudspeaker using a shunt circuit through electro-mechanical coupling, which induces reactance with different signs from that of loudspeaker. An RLC shunt circuit is connected to the moving coil to provide an electrically induced mechanical impedance which counters the cavity stiffness at low frequencies and reduces the system inertia above the resonance frequency. A sound absorption coefficient well above 0.5 is demonstrated across frequencies between 150 and 1200 Hz. The performance of the proposed device is superior to existing passive absorbers of the same depth (60 mm), which has lower frequency limits of around 300 Hz. A passive noise absorber is further proposed by paralleling a micro-perforated panel with shunted loudspeaker which shows potentials in absorbing band-limit impulse noise.
N. Suzuki, T. Sato, T.-S. H. Lee
2010-10-01
We explain the application of a recently developed analytic continuation method to extract the electromagnetic transition form factors for the nucleon resonances ($N^*$) within a dynamical coupled-channel model of meson-baryon reactions.Illustrative results of the obtained $N^*\\rightarrow \\gamma N$ transition form factors, defined at the resonance pole positions on the complex energy plane, for the well isolated $P_{33}$ and $D_{13}$, and the complicated $P_{11}$ resonances are presented. A formula has been developed to give an unified representation of the effects due to the first two $P_{11}$ poles, which are near the $\\pi\\Delta$ threshold, but are on different Riemann sheets. We also find that a simple formula, with its parameters determined in the Laurent expansions of $\\pi N \\rightarrow \\pi N$ and $\\gamma N \\rightarrow\\pi N$ amplitudes, can reproduce to a very large extent the exact solutions of the considered model at energies near the real parts of the extracted resonance positions. We indicate the differences between our results and those extracted from the approaches using the Breit-Wigner parametrization of resonant amplitudes to fit the data.
Bagci, Fulya; Akaoglu, Baris
2017-08-01
We present a metamaterial configuration exhibiting single and multi-band electromagnetic induced transparency (EIT)-like properties. The unit cell of the single band EIT-like metamaterial consists of a multi-split ring resonator surrounded by a split ring resonator. The multi-split ring resonator acts as a quasi-dark or dark resonator, depending on the polarization of the incident wave, and the split ring resonator serves as the bright resonator. Combination of these two resonators results in a single band EIT-like transmission inside the stop band. EIT-like transmission phenomenon is also clearly observed in the measured transmission spectrum at almost the same frequencies for vertical and horizontal polarized waves, and the numerical results are verified for normal incidence. Moreover, multi-band transmission windows are created within a wide band by combining the two slightly different single band EIT-like metamaterial unit cells that exhibit two different coupling strengths inside a supercell configuration. Group indices as high as 123 for single band and 488 for tri-band transmission, accompanying with high transmission rates (over 80%), are achieved, rendering the metamaterial very suitable for multi-band slow light applications. It is shown that the group delay of the propagating wave can be increased and dynamically controlled by changing the polarization angle. Multi-band EIT-like transmission is also verified experimentally, and a good agreement with simulations is obtained. The proposed novel methodology for obtaining multi-band EIT, which takes advantage of a supercell configuration by hosting slightly different configured unit cells, can be utilized for easily formation and manipulation of multi-band transmission windows inside a stop band.
Efficient Radiation by Electrically Small Antennas made of Coupled Split-ring Resonators
Peng, Liang; Chen, Peiwei; Wu, Aiting; Wang, Gaofeng
2016-09-01
In this paper, coupled split-ring resonators (SRRs) are used to construct the electrically small antennas. We show that through strong magnetic coupling, the coupled SRRs composite can oscillate at a wavelength much larger than its total size. Due to its magnetic dipole feature, the coupled SRRs composite allows the electromagnetic (EM) power to radiate and hence forms the electrically small antenna (ESA). Because of the high-Q resonance, the ESA could be easily matched to the driving circuit in the microwave region, through mutual induction approach. We also demonstrate that the radiation efficiency of such ESAs can be drastically improved if the current distribution on individual SRRs is similar, which is achievable by carefully designing the ESAs. From our simulations and experimental measurements, the ESAs’ radiation efficiency can reach up to 41%, with relative footprint of 0.05λ0 × 0.05λ0. Our approach would be an effective way to realize ESAs with high efficiency, which can be implemented on chip through the standard planar lithography.
Coupled Mechanical and Electrochemical Phenomena in Lithium-Ion Batteries
Cannarella, John
Lithium-ion batteries are complee electro-chemo-mechanical systems owing to a number of coupled mechanical and electrochemical phenomena that occur during operation. In this thesis we explore these phenomena in the context of battery degradation, monitoring/diagnostics, and their application to novel energy systems. We begin by establishing the importance of bulk stress in lithium-ion batteries through the presentation of a two-year exploratory aging study which shows that bulk mechanical stress can significantly accelerate capacity fade. We then investigate the origins of this coupling between stress and performance by investigating the effects of stress in idealized systems. Mechanical stress is found to increase internal battery resistance through separator deformation, which we model by considering how deformation affects certain transport properties. When this deformation occurs in a spatially heterogeneous manner, local hot spots form, which accelerate aging and in some cases lead to local lithium plating. Because of the importance of separator deformation with respect to mechanically-coupled aging, we characterize the mechanical properties of battery separators in detail. We also demonstrate that the stress state of a lithium-ion battery cell can be used to measure the cell's state of health (SOH) and state of charge (SOC)--important operating parameters that are traditionally difficult to measure outside of a laboratory setting. The SOH is shown to be related to irreversible expansion that occurs with degradation and the SOC to the reversible strains characteristic of the cell's electrode materials. The expansion characteristics and mechanical properties of the constituent cell materials are characterized, and a phenomenological model for the relationship between stress and SOH/SOC is developed. This work forms the basis for the development of on-board monitoring of SOH/SOC based on mechanical measurements. Finally we study the coupling between mechanical
M. Durga Prasad
2002-05-01
Full Text Available Abstract: A time dependent coupled cluster approach to the calculation of Resonance Raman excitation profiles on general anharmonic surfaces is presented. The vibrational wave functions on the ground electronic surface are obtained by the coupled cluster method (CCM. It is shown that the propagation of the vibrational ground state on the upper surface is equivalent to propagation of the vacuum state by an effective hamiltonian generated by the similarity transformation of the vibrational hamiltonian of that surface by the CCM wave operator of the lower surface up to a normalization constant. This time propagation is carried out by the time-dependent coupled cluster method in a time dependent frame. Numerical studies are presented to asses the validity of the approach.
Q-switched operation of a coupled-resonator vertical-cavity laser diode
FISCHER,ARTHUR J.; CHOW,WENG W.; CHOQUETTE,KENT D.; ALLERMAN,ANDREW A.; GEIB,KENT M.
2000-02-08
The authors report Q-switched operation from an electrically-injected monolithic coupled-resonator structure which consists of an active cavity with InGaAs quantum wells optically coupled to a passive cavity. The passive cavity contains a bulk GaAs region which is reverse-biased to provide variable absorption at the lasing wavelength of 990 nm. Cavity coupling is utilized to effect large changes in output intensity with only very small changes in passive cavity absorption. The device is shown to produce pulses as short as 150 ps at repetition rates as high 4 GHz. A rate equation approach is used to model the Q-switched operation yielding good agreement between the experimental and theoretical pulse shape. Small-signal frequency response measurements also show a transition from a slower ({approximately} 300 MHZ) forward-biased modulation regime to a faster ({approximately} 2 GHz) modulation regime under reverse-bias operation.
Bonizzoni, C; Ghirri, A; Bader, K; van Slageren, J; Perfetti, M; Sorace, L; Lan, Y; Fuhr, O; Ruben, M; Affronte, M
2016-11-14
We present spectroscopic measurements looking for the coherent coupling between molecular magnetic centers and microwave photons. The aim is to find the optimal conditions and the best molecular features to achieve the quantum strong coupling regime, for which coherent dynamics of hybrid photon-spin states take place. To this end, we used a high critical temperature YBCO superconducting planar resonator working at 7.7 GHz and at low temperatures to investigate three molecular mononuclear coordination compounds, namely (PPh4)2[Cu(mnt)2] (where mnt(2-) = maleonitriledithiolate), [ErPc2](-)TBA(+) (where pc(2-) is the phtalocyaninato and TBA(+) is the tetra-n-butylammonium cation) and Dy(trensal) (where H3trensal = 2,2',2''-tris(salicylideneimino)triethylamine). Although the strong coupling regime was not achieved in these preliminary experiments, the results provided several hints on how to design molecular magnetic centers to be integrated into hybrid quantum circuits.
Strong coupling of an Er3+-doped YAlO3 crystal to a superconducting resonator
Tkalčec, A.; Probst, S.; Rieger, D.; Rotzinger, H.; Wünsch, S.; Kukharchyk, N.; Wieck, A. D.; Siegel, M.; Ustinov, A. V.; Bushev, P.
2014-08-01
Quantum memories are integral parts of both quantum computers and quantum communication networks. Naturally, such a memory is embedded into a hybrid quantum architecture, which has to meet the requirements of fast gates, long coherence times, and long distance communication. Erbium-doped crystals are well suited as a microwave quantum memory for superconducting circuits with additional access to the optical telecom C band around 1.55 μm. Here, we report on circuit QED experiments with an Er3+:YAlO3 crystal and demonstrate strong coupling to a superconducting lumped element resonator. The low magnetic anisotropy of the host crystal allows for attaining the strong coupling regime at relatively low magnetic fields, which are compatible with superconducting circuits. In addition, Ce3+ impurities were detected in the crystal, which showed strong coupling as well.
Mode Modification of Plasmonic Gap Resonances induced by Strong Coupling with Molecular Excitons
Chen, Xingxing; Qin, Jian; Zhao, Ding; Ding, Boyang; Blaikie, Richard J; Qiu, Min
2016-01-01
Plasmonic cavities can be used to control the atom-photon coupling process at the nanoscale, since they provide ultrahigh density of optical states in an exceptionally small mode volume. Here we demonstrate strong coupling between molecular excitons and plasmonic resonances (so-called plexcitonic coupling) in a film-coupled nanocube cavity, which can induce profound and significant spectral and spatial modifications to the plasmonic gap modes. Within the spectral span of a single gap mode in the nanotube-film cavity with a 3-nm wide gap, the introduction of narrow-band J-aggregate dye molecules not only enables an anti-crossing behavior in the spectral response, but also splits the single spatial mode into two distinct modes that are easily identified by their far-field scattering profiles. Simulation results confirm the experimental findings and the sensitivity of the plexcitonic coupling is explored using digital control of the gap spacing. Our work opens up a new perspective to study the strong coupling pr...
Mitskovets, Anya; Gopinath, Ashwin; Rothemund, Paul; Atwater, Harry A.
2016-09-01
Interfacing of single photon emitters, such as quantum dots, with photonic nanocavities enables study of fundamental quantum electrodynamic phenomena. In such experiments, the inability to precisely position quantum emitters at the nanoscale usually limits the ability to control spontaneous emission, despite sophisticated control of optical density of states by cavity design. Thus, effective light-matter interactions in photonic nanostructures strongly depend on deterministic positioning of quantum emitters. In this work by using directed self-assembly of DNA origami we demonstrate deterministic coupling of quantum dots with gallium phosphide (GaP) dielectric whispering gallery mode resonators design to enhance CdSe quantum dot emission at 600nm-650nm. GaP microdisk and microring resonators are dry-etched through 200nm layer of gallium phosphide on silicon dioxide/silicon substrates. Our simulations show that such GaP resonators may have quality factors up to 10^5, which ensures strong light-matter interaction. On the top surface of microresonators, we write binding sites in the shape of DNA origami using electron beam lithography, and use oxygen plasma exposure to chemically activate these binding sites. DNA origami self-assembly is accomplished by placing DNA origami - quantum dot complexes into these binding sites. This approach allows us to achieve deterministic placement of the quantum dots with a few nm precision in position relative to the resonator. We will report photoluminescence spectroscopy and lifetime measurements of quantum dot - resonator deterministic coupling to probe the cavity-enhanced spontaneous emission rate. Overall, this approach offers precise control of emitter positioning in nanophotonic structures, which is a critical step for scalable quantum information processing.
Mechanical Properties of a Primary Cilium Measured by Resonant Oscillation
Resnick, Andrew
Primary cilia are ubiquitous mammalian cellular substructures implicated in an ever-increasing number of regulatory pathways. The well-established `ciliary hypothesis' states that physical bending of the cilium (for example, due to fluid flow) initiates signaling cascades, yet the mechanical properties of the cilium remain incompletely measured, resulting in confusion regarding the biological significance of flow-induced ciliary mechanotransduction. In this work we measure the mechanical properties of a primary cilium by using an optical trap to induce resonant oscillation of the structure. Our data indicate 1), the primary cilium is not a simple cantilevered beam, 2), the base of the cilium may be modeled as a nonlinear rotatory spring, the linear spring constant `k' of the cilium base calculated to be (4.6 +/- 0.62)*10-12 N/rad and nonlinear spring constant ` α' to be (-1 +/- 0.34) *10-10 N/rad2 , and 3) the ciliary base may be an essential regulator of mechanotransduction signalling. Our method is also particularly suited to measure mechanical properties of nodal cilia, stereocilia, and motile cilia, anatomically similar structures with very different physiological functions.
Dielectric micro-resonator-based opto-mechanical systems for sensing applications
Ali, Amir Roushdy
In recent years, whispering gallery mode (WGM), or morphology dependent optical resonances (MDR) of dielectric micro-resonators have attracted interest with proposed applications in a wide range of areas due to the high optical quality factors, Q, they can exhibit (reaching ~ 10. 9 for silica spheres). Micro-resonator WGMs have been used in applications that include those in spectroscopy, micro-cavity laser technology, optical communications (switching, filtering and multiplexing), sensors technologies and even chemical and biological sensing. The WGM of these dielectric micro-resonators are highly sensitive to morphological changes (such as the size, shape, or refractive index) of the resonance cavity and hence, can be tuned by causing a minute change in the physical condition of the surrounding. In this dissertation, we have been creating opto-mechanical systems, which at their most basic, are extraordinarily sensitive sensors. One of the ultimate goals of this dissertation is to develop sensors capable of detecting the extremely small electric field changes. To improve the performance of the sensors, we couple a polymer cantilever beam to a dielectric micro-resonator. The eventual use of such ultra sensitive electric filed sensors could include neural-machine interfaces for advanced prosthetics devices. The work presented here includes a basic analysis and experimental investigations of the electric field sensitivity and range of micro-resonators of several different materials and geometries followed by the electric field sensor design, testing, and characterization. Also, the effects of angular velocity on the WGM shifts of spherical micro-resonators are also investigated. The elastic deformation that is induced on a spinning resonator due to the centrifugal force may lead to a sufficient shift in the optical resonances and therefore interfering with its desirable operational sensor design. Furthermore, this principle could be used for the development of
Abdelrehim, Adel A. A.; Ghafouri-Shiraz, H.
2016-09-01
In this paper, three dimensional periodic structure composed of circular split ring resonators and thin wires is used to improve the performance of a microstrip patch antenna. The three dimensional periodic structure is placed at the top of the patch within a specific separation distance to construct the proposed antenna. The radiated electromagnetic waves intensity of the proposed antenna is improved compared with the conventional patch antenna due to the electric and magnetic coupling enhancements. These enhancements occur between the patch and the periodic structure resonators and between the different resonator pairs of the periodic structure. As a result, the electric and the magnetic fields at the top of the patch are improved, the radiated electromagnetic beam size reduces which results in a highly focused beam and hence the antenna directivity and gain are improved, while the beam are is reduced. The proposed antenna has been designed and simulated using CST microwave studio at 10 GHz. An infinite two dimensional periodicity unit cell of circular split ring resonator and thin wire is designed to resonate at a 10 GHz and simulated in CST software, the scattering parameters are extracted, the results showed that the infinite periodicity two dimensional structure has a pass band frequency response of good transmission and reflection characteristics around 10 GHz. The infinite periodicity of the two dimensional periodic structure is then truncated and multi layers of such truncated structure is used to construct a three dimensional periodic structure. A parametric analysis has been performed on the proposed antenna incorporated with the three dimensional periodic structure. The impacts of the separation distance between the patch and three dimensional periodic structures and the size of the three dimensional periodic structure on the radiation and impedance matching parameters of the proposed antenna are studied. For experimental verification, the proposed
Goodlet, B R; Torbet, C J; Biedermann, E J; Jauriqui, L M; Aldrin, J C; Pollock, T M
2017-02-08
Finite element (FE) modeling has been coupled with resonant ultrasound spectroscopy (RUS) for nondestructive evaluation (NDE) of high temperature damage induced by mechanical loading. Forward FE models predict mode-specific changes in resonance frequencies (ΔfR), inform RUS measurements of mode-type, and identify diagnostic resonance modes sensitive to individual or multiple concurrent damage mechanisms. The magnitude of modeled ΔfR correlate very well with the magnitude of measured ΔfR from RUS, affording quantitative assessments of damage. This approach was employed to study creep damage in a polycrystalline Ni-based superalloy (Mar-M247) at 950°C. After iterative applications of creep strains up to 8.8%, RUS measurements recorded ΔfR that correspond to the accumulation of plastic deformation and cracks in the gauge section of a cylindrical dog-bone specimen. Of the first 50 resonance modes that occur, ranging from 3 to 220kHz, modes classified as longitudinal bending were most sensitive to creep damage while transverse bending modes were found to be largely unaffected. Measure to model comparisons of ΔfR show that the deformation experienced by the specimen during creep, specifically uniform elongation of the gauge section, is responsible for a majority of the measured ΔfR until at least 6.1% creep strain. After 8.8% strain considerable surface cracking along the gauge section of the dog-bone was observed, for which FE models indicate low-frequency longitudinal bending modes are significantly affected. Key differences between historical implementations of RUS for NDE and the FE model-based framework developed herein are discussed, with attention to general implementation of a FE model-based framework for NDE of damage.
Liu, Peter Q.; Luxmoore, Isaac J.; Mikhailov, Sergey A.; Savostianova, Nadja A.; Valmorra, Federico; Faist, Jérôme; Nash, Geoffrey R.
2015-11-01
Metamaterials and plasmonics are powerful tools for unconventional manipulation and harnessing of light. Metamaterials can be engineered to possess intriguing properties lacking in natural materials, such as negative refractive index. Plasmonics offers capabilities of confining light in subwavelength dimensions and enhancing light-matter interactions. Recently, the technological potential of graphene-based plasmonics has been recognized as the latter features large tunability, higher field-confinement and lower loss compared with metal-based plasmonics. Here, we introduce hybrid structures comprising graphene plasmonic resonators coupled to conventional split-ring resonators, thus demonstrating a type of highly tunable metamaterial, where the interaction between the two resonances reaches the strong-coupling regime. Such hybrid metamaterials are employed as high-speed THz modulators, exhibiting ~60% transmission modulation and operating speed in excess of 40 MHz. This device concept also provides a platform for exploring cavity-enhanced light-matter interactions and optical processes in graphene plasmonic structures for applications including sensing, photo-detection and nonlinear frequency generation.
Liu, Peter Q; Luxmoore, Isaac J; Mikhailov, Sergey A; Savostianova, Nadja A; Valmorra, Federico; Faist, Jérôme; Nash, Geoffrey R
2015-11-20
Metamaterials and plasmonics are powerful tools for unconventional manipulation and harnessing of light. Metamaterials can be engineered to possess intriguing properties lacking in natural materials, such as negative refractive index. Plasmonics offers capabilities of confining light in subwavelength dimensions and enhancing light-matter interactions. Recently, the technological potential of graphene-based plasmonics has been recognized as the latter features large tunability, higher field-confinement and lower loss compared with metal-based plasmonics. Here, we introduce hybrid structures comprising graphene plasmonic resonators coupled to conventional split-ring resonators, thus demonstrating a type of highly tunable metamaterial, where the interaction between the two resonances reaches the strong-coupling regime. Such hybrid metamaterials are employed as high-speed THz modulators, exhibiting ∼60% transmission modulation and operating speed in excess of 40 MHz. This device concept also provides a platform for exploring cavity-enhanced light-matter interactions and optical processes in graphene plasmonic structures for applications including sensing, photo-detection and nonlinear frequency generation.
In vitro evaluation of genotoxic effects under magnetic resonant coupling wireless power transfer.
Mizuno, Kohei; Shinohara, Naoki; Miyakoshi, Junji
2015-04-07
Wireless power transfer (WPT) technology using the resonant coupling phenomenon has been widely studied, but there are very few studies concerning the possible relationship between WPT exposure and human health. In this study, we investigated whether exposure to magnetic resonant coupling WPT has genotoxic effects on WI38VA13 subcloned 2RA human fibroblast cells. WPT exposure was performed using a helical coil-based exposure system designed to transfer power with 85.4% efficiency at a 12.5-MHz resonant frequency. The magnetic field at the positions of the cell culture dishes is approximately twice the reference level for occupational exposure as stated in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. The specific absorption rate at the positions of the cell culture dishes matches the respective reference levels stated in the ICNIRP guidelines. For assessment of genotoxicity, we studied cell growth, cell cycle distribution, DNA strand breaks using the comet assay, micronucleus formation, and hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene mutation, and did not detect any significant effects between the WPT-exposed cells and control cells. Our results suggest that WPT exposure under the conditions of the ICNIRP guidelines does not cause detectable cellular genotoxicity.
M. Abdel-Rahman
2015-01-01
Full Text Available We report on the fabrication and characterization of a novel antenna-coupled detector configuration for detection at 94 GHz, a coplanar waveguide- (CPW- fed, slot-excited twin dielectric resonator antenna- (DRA- coupled niobium (Nb microbolometer. The antenna is based on two low permittivity cylindrical dielectric resonators (CDRs excited by rectangular slots placed below the CDRs. The antenna resonant currents are fed to an Nb microbolometer by the means of a CPW feed. The ceramic DRA structure is manufactured using a novel fabrication process that enables patterning an SU-8–Alumina (Al2O3 nanopowder composite using conventional photolithography. The detector measured a voltage responsivity of 0.181 V/W at a modulation frequency of 150 Hz. The detector measured a time constant of 1.94 μs. The antenna radiation pattern of the developed detector configuration was measured and shows a good agreement with the simulation.
Suh, Jeewon; Han, Kewen; Peterson, Christopher; Bahl, Gaurav
2017-02-01
Resonant optical sensors have enabled the label-free measurement of nanoparticles suspended in liquids, down to the resolution of individual viruses and large molecules, but are only able to quantify optical properties (refractive index, scattering, fluorescence). Additionally, these sensors are fundamentally limited by the random diffusion of particles to the sensing region, and thus only quantify a tiny fraction of the analyte. We have developed a microfluidic optomechanical resonator capable of sensing flowing nanoparticles using the action of phonons that are coupled to light. The phonon mode of the system casts a nearly perfect net for measuring density, viscoelasticity, and compressibility of the particles that flow through, without being limited by random diffusion. Information on the particle mechanical properties is encoded in the light scattered from the thermal fluctuations of the phonon mode, and measurements at a timescale of below 20 milliseconds have been demonstrated previously. In this work, we develop a new experimental method for improving the signal-to-noise ratio (SNR) and sensing speed achievable with this technique, by implementing electro-opto-mechanical transduction. We demonstrate real-time particle transit measurements as fast as 400 microseconds, a factor of 50x improvement in speed, without any post-processing. We discuss how this novel technique can be used for ultra-high throughput analysis of mechanical properties of biological particles in liquids, enabling a new form of flow cytometry.
A fully coupled thermo-mechanical model for unsaturated soil
2007-01-01
This paper addresses a new, unified thermomechanical constitutive model for unsaturated soils through a coupled study. In the context of elastoplasticity and the critical state theory, the model uses the concepts of multi-mechanism and bounding surface theory. This advanced constitutive approach involves thermo-plasticity of saturated and unsaturated soils. Bishop’s effective stress framework is adopted to represent the stress state in the soil. This stress is linked to the water retention...
Bettotti, P; Mancinelli, M; Guider, R; Masi, M; Vanacharla, M Rao; Pavesi, L
2011-04-15
A novel (to our knowledge) scheme of an optical router/switch element, composed of a tapered side-coupled integrated spaced sequence of optical resonators, is proposed. It is based on a modified design of the ring sequence in which the resonance conditions are set by the single ring resonance and by the coherent feedback of the sequence of rings. This double condition yields robustness against fabrication defects, dense routing capability, and high switching efficiency.
HAN Xiu-you; PANG Fu-fei; FANG Zu-jie; ZHAO Ming-shan
2008-01-01
Based on the measurement of the contrast ratios of the transmission spectra from the throughput and drop ports of ring resonator, an efficient method is proposed to extract the coupling ratio and round-trip loss of the integrated optical waveguide ring resonator. The parameters of a racetrack resonator prepared by ion-exchange technique in K9 optical glass substrate are examined, which demonstrates the validity of this method. The accuracy and applicable range of this method are also discussed.
Yang, Yi; Peng, Chao; Liang, Yong; Li, Zhengbin; Noda, Susumu
2014-08-01
A general coupled-wave theory is presented for the guided resonance in photonic crystal (PhC) slabs with TM-like polarization. Numerical results based on our model are presented with finite-difference time-domain validations. The proposed analysis facilitates comprehensive understanding of the physics of guided resonance in PhC slabs and provides guidance for its applications.
Insights into Coupled Folding and Binding Mechanisms from Kinetic Studies.
Shammas, Sarah L; Crabtree, Michael D; Dahal, Liza; Wicky, Basile I M; Clarke, Jane
2016-03-25
Intrinsically disordered proteins (IDPs) are characterized by a lack of persistent structure. Since their identification more than a decade ago, many questions regarding their functional relevance and interaction mechanisms remain unanswered. Although most experiments have taken equilibrium and structural perspectives, fewer studies have investigated the kinetics of their interactions. Here we review and highlight the type of information that can be gained from kinetic studies. In particular, we show how kinetic studies of coupled folding and binding reactions, an important class of signaling event, are needed to determine mechanisms.
Schultz, Zachary D; Dekhter, Rimma; Anestopoulos, Dimitris; Grammatikopoulos, Spyridon; Papagelis, Kostantinos; Marr, James M; Lewis, David; Galiotis, Costas; Lev, Dimtry; Lewis, Aaron
2016-01-01
Tip enhanced Raman scattering (TERS) amplifies the intensity of vibrational Raman scattering by employing the tip of a probe interacting, in ultra close proximity, with a surface. Although a general understanding of the TERS process is still to be fully elucidated, scanning tunneling microscopy (STM) feedback is often applied with success in TERS to keep a noble metal probe in intimate proximity with a noble metal substrate. Since such STM TERS is a common modality, the possible implications of plasmonic fields that may be induced by the tunneling process are investigated and reported. In addition, TERS of a 2D resonant molecular system, a MoS2 bilayer crystal and a 2D non-resonant, lipid molecular bilayer is compared. Data with multiple excitation wavelengths and surfaces for the resonant system in the near- (TERS) and far-field regimes are reported. An interpretation based on weak coupling interactions within the framework of conventional resonance Raman scattering can explain the observed TERS enhancements...
Synchronization and array-enhanced resonances in delayed coupled neuronal network with channel noise
Chen, Jianchun; Ding, Shaojie; Li, Hui; He, Guolong; Zhang, Xuejuan
2014-09-01
This paper studies the combined effect of transmission delay and channel fluctuations on population behaviors of an excitatory Erdös-Rényi neuronal network. First, it is found that the network reaches a perfect spatial temporal coherence at a suitable membrane size. Such a coherence resonance is stimulus-free and is array-enhanced. Second, the presence of transmission delay can induce intermittent changes of the population dynamics. Besides, two resonant peaks of the population firing rate are observed as delay changes: one is at τd≈7ms for all membrane areas, which reflects the resonance between the delayed interaction and the intrinsic period of channel kinetics; the other occurs when the transmission delay equals to the mean inter-spike intervals of the population firings in the absence of delay, which reflects the resonance between the delayed interaction and the firing period of the non-delayed system. Third, concerning the impact of network topology and population size, it is found that decreasing the connection probability does not change the range of transmission delay but broadens the range of synaptic coupling that supports population neurons to generate action potentials synchronously and temporally coherently. Furthermore, there exists a critical connection probability that distinguishes the population dynamics into an asynchronous and synchronous state. All the results we obtained are based on networks of size N = 500, which are shown to be robust to further increasing the population size.
Bandwidth tunable guided-mode resonance filter using contact coupled gratings at oblique incidence
Sang, Tian; Wang, Yueke; Li, Junlang; Zhou, Jianyu; Jiang, Wenwen; Wang, Jicheng; Chen, Guoqing
2017-01-01
A novel bandwidth tunable guided-mode resonance filter (GMRF) is proposed based on the contact coupled gratings (CCGs) with the absentee layers at oblique incidence. The design principle of the CCGs with double absentee layers is presented. The lateral shift of the CCGs changes the magnetic field distributions of the waveguide mode in the grating cavity and the surface-confined mode at the cover/grating interface thus facilitates the dynamic control of both the spectral and angular bandwidth of the GMRF. The resonance locations are almost immune to the variation of the lateral shift of the CCGs. The sideband level of the GMRF is almost unaffected by the lateral shift due to the Brewster AR effect. The resonance peak red-shifts quasi-linearly as the incident angle is increased, and the resonance wavelength can be selected by merely tuning the incident angle. The tunable ranges of both the spectral and angular bandwidth can be significantly enhanced by increasing the refractive-index contrast. Low-sideband reflection with controllable bandwidth at 650 nm is designed to demonstrate this concept.
A coupled elasto-plastic-damage mechanical model for marble
无
2011-01-01
A profound understanding of the mechanical behaviors of marble is very important for the design and construction of deep diversion tunnels in Jinping II hydropower station.In this paper,a coupled elasto-plastic-damage mechanical model is presented for Jinping marble.Firstly,the experimental investigations on Jinping marble are summarized.Then,based on the framework of continuum damage and plastic theories,a general mechanical model is proposed to predict the mechanical responses of Jinping marble.The proposed model is used to simulate the triaxial compressive tests,and there is a general good agreement between experimental data and numerical predictions in a qualitative manner.The proposed model is able to capture the main features of Jinping marble observed in experiments,such as progressive yielding process,damage induced by plastic distortion,dilation,elastic degradation and stress sensitivity.
Residual Dipolar Couplings in Zero-to-Ultra-Low-Field Nuclear Magnetic Resonance
Blanchard, John W; King, Jonathan P; Ledbetter, Micah P; Levine, Emma H; Bajaj, Vikram S; Budker, Dmitry; Pines, Alexander
2015-01-01
Zero-to-ultra-low-field nuclear magnetic resonance (ZULF-NMR) provides a new regime for the measurement of nuclear spin-spin interactions free from effects of large magnetic fields, such as truncation of terms that do not commute with the Zeeman Hamiltonian. One such interaction, the magnetic dipole-dipole coupling, is a valuable source of spatial information in NMR, though many terms are unobservable in high-field NMR, and the interaction averages to zero under isotropic molecular tumbling. Under partial orientational ordering, this information is retained in the form of so-called residual dipolar couplings. We report zero-to-ultra-low-field NMR measurements of residual dipolar couplings in acetonitrile-2-$^{13}$C aligned in stretched polyvinyl acetate gels. This represents the first investigation of dipolar couplings as a perturbation on the indirect spin-spin $J$-coupling in the absence of an applied magnetic field. As a consequence of working at zero magnetic field, we observe terms of the dipole-dipole c...
Xue-Liang Zhang; Bang-Chun Wen; Chun-Yu Zhao
2012-01-01
In this paper,the synchronization problem of three homodromy coupled exciters in a non-resonant vibrating system of plane motion is studied.By introducing the average method of modified small parameters,we deduced dimensionless coupling equation of three exciters,which converted the problem of synchronization into that of the existence and stability of zero solutions for the average differential equations of the small parameters.Based on the dimensionless coupling torques and characteristics of the corresponding limited functions,the synchronization criterion for three exciters was derived as the absolute value of dimensionless residual torque difference between arbitrary two motors being less than the maximum of their dimensionless coupling torques.The stability criterion of its synchronous state lies in the double-condition that the inertia coupling matrix is positive definite and all its elements are positive as well.The synchronization determinants are the coefficients of synchronization ability,also called as the general dynamical symmetry coefficients.The double-equilibrium state of the vibrating system is manifested by numeric method,and the numeric and simulation results derived thereof indicate the indispensable and crucial role the structural parameters of the vibrating system play in the stability criterion of synchronous operation.Besides,by adjusting its structural parameters,the elliptical motion of the vibrating system successfully met the requirements in engineering applications.
Coupling Influence on Signal Readout of a Dual-Parameter LC Resonant System
Jijun Xiong
2015-01-01
Full Text Available Dual-parameter inductive-capacitive (LC resonant sensor is gradually becoming the measurement trend in complex harsh environments; however, the coupling between inductors greatly affects the readout signal, which becomes very difficult to resolve by means of simple mathematical tools. By changing the values of specific variables in a MATLAB code, the influence of coupling between coils on the readout signal is analyzed. Our preliminary conclusions underline that changing the coupling to antenna greatly affects the readout signal, but it simultaneously influences the other signal. When f01=f02, it is better to broaden the difference between the two coupling coefficients k1 and k2. On the other side, when f01 is smaller than f02, it is better to decrease the coupling between sensor inductors k12, in order to obtain two readout signals averaged in strength. Finally, a test system including a discrete capacitor soldered to a printed circuit board (PCB based planar spiral coil is built, and the readout signals under different relative inductors positions are analyzed. All experimental results are in good agreement with the results of the MATLAB simulation.
Zhou, Xiaoyan; Pang, Wei; Zhang, Hao; Yang, Qingrui; Zhang, Daihua
2013-01-01
Electromagnetically induced transparency (EIT) and EIT-like effects have been investigated in a wide variety of coupled resonant systems. Here, a classification of the phase characteristics of the EIT-like spectral responses is presented. Newly identified phase responses reveal unexplored operation regimes of EIT-like systems. Taking advantage of the new phase regimes, one can obtain group delay, dispersion and nonlinearity properties greatly enhanced by almost one order of magnitude, compared to the traditionally constructed EIT-like devices, which breaks the fundamental limitation (e.g., delay-bandwidth product) intrinsic to atomic EIT and EIT-like effects. Optical devices and electrical circuits are analyzed as examples showing the universality of our finding. We show that cavity-QED-based quantum phase gates can be greatly improved to achieve a phase shift of {\\pi}. The new phase characteristics are also believed to be useful to build novel doubly resonant devices in quantum information based on cavity QE...
Temporal coupled mode theory of standing wave resonant cavities for infrared photodetection.
Lesmanne, Emeline; De Lamaestre, Roch Espiau; Fowler, David; Boutami, Salim; Badano, Giacomo
2015-03-23
Standing wave resonating cavities have been proposed in the past to increase the performance of infrared detectors by minimizing the volume of photogeneration, hence the noise, while maintaining the same quantum efficiency. We present an approach based on the temporal coupled mode theory to explain their behavior and limitations. If the ratio of the imaginary part of the absorber's dielectric function to the index of the incident medium ε″(d)/n₀ is larger than 1.4, then the absorption cross section σ(a) can attain its maximum value, which for an isolated cavity is approximately 2λ/π. Besides, for σ(a) to exceed the cavity width, the incident medium refractive index must be close to unity. Metallic loss is negligible in the infrared, making those resonators suitable for integration in infrared photodetectors.
Plasmonic metalens based on coupled resonators for focusing of surface plasmons
Xu, Quan
2016-11-29
As an essential functionality, flexible focusing of surface plasmons (SPs) is of particular interest in nonlinear optics and highly integrated plasmonic circuitry. Here, we developed a versatile plasmonic metalens, a metasurface comprised of coupled subwavelength resonators, whose optical responses exhibit a remarkable feature of electromagnetically induced transparency (EIT). We demonstrate numerically and experimentally how a proper spatial design of the unit elements steers SPs to arbitrary foci based on the holographic principles. More specifically, we show how to control the interaction between the constituent EIT resonators to efficiently manipulate the focusing intensity of SPs. We also demonstrated that the proposed metalens is capable of achieving frequency division multiplexing. The power and simplicity of the proposed design would offer promising opportunities for practical plasmonic devices.
Xu, Fang; Poon, Andrew W
2008-06-09
We report silicon cross-connect filters using microring resonator coupled multimode-interference (MMI) based waveguide crossings. Our experiments reveal that the MMI-based cross-connect filters impose lower crosstalk at the crossing than the conventional cross-connect filters using plain crossings, while offering a nearly symmetric resonance line shape in the drop-port transmission. As a proof-of-concept for cross-connection applications, we demonstrate on a silicon-on-insulator substrate (i) a 4-channel 1 x 4 linear-cascaded MMI-based cross-connect filter, and (ii) a 2-channel 2 x 2 array-cascaded MMI-based cross-connect filter.
Tunable Plasmonic Band-Pass Filter with Dual Side-Coupled Circular Ring Resonators
Dongdong Liu
2017-03-01
Full Text Available A wavelength band-pass filter with asymmetric dual circular ring resonators in a metal-insulator-metal (MIM structure is proposed and numerically simulated. For the interaction of the local discrete state and the continuous spectrum caused by the side-coupled resonators and the baffle, respectively, the transmission spectrum exhibits a sharp and asymmetric profile. By adjusting the radius and material imbedded in one ring cavity, the off-to-on plasmon-induced absorption (PIA optical response can be tunable achieved. In addition, the structure can be easily extended to other similar compact structures to realize the filtering task. Our structures have important potential applications for filters and sensors at visible and near-infrared regions.
Extra loss due to Fano resonances in inhibited coupling fibers based on a lattice of tubes.
Vincetti, L; Setti, V
2012-06-18
Confinement loss of inhibited coupling fibers with a cladding composed of a lattice of tubes of various shapes is theoretically and numerically investigated. Both solid core and hollow core are taken into account. It is shown that in case of polygonal shaped tubes, confinement loss is affected by extra loss due to Fano resonances between core modes and cladding modes with high spatial dependence. This explains why hollow core Kagome fibers exhibit much higher confinement loss with respect to tube lattice fibers and why hypocycloid core cladding interfaces significantly reduce fiber loss. Moreover it is shown that tube deformations, due for example to fabrication process, affect fiber performances. A relationship between the number of polygon sides and the spectral position of the extra loss is found. This suggests general guide lines for the design and fabrication of fibers free of Fano resonance in the spectral range of interest.
Plasmonic metalens based on coupled resonators for focusing of surface plasmons
Xu, Quan; Zhang, Xueqian; Xu, Yuehong; Li, Quan; Li, Yanfeng; Ouyang, Chunmei; Tian, Zhen; Gu, Jianqiang; Zhang, Wentao; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili
2016-11-01
As an essential functionality, flexible focusing of surface plasmons (SPs) is of particular interest in nonlinear optics and highly integrated plasmonic circuitry. Here, we developed a versatile plasmonic metalens, a metasurface comprised of coupled subwavelength resonators, whose optical responses exhibit a remarkable feature of electromagnetically induced transparency (EIT). We demonstrate numerically and experimentally how a proper spatial design of the unit elements steers SPs to arbitrary foci based on the holographic principles. More specifically, we show how to control the interaction between the constituent EIT resonators to efficiently manipulate the focusing intensity of SPs. We also demonstrated that the proposed metalens is capable of achieving frequency division multiplexing. The power and simplicity of the proposed design would offer promising opportunities for practical plasmonic devices.
Coupled-resonator optical waveguides: Q-factor and disorder influence
Grgic, J; Raza, S; Bassi, P; Mortensen, N A
2010-01-01
Coupled resonator optical waveguides (CROW) can significantly reduce light propagation pulse velocity due to pronounced dispersion properties. A number of interesting applications have been proposed to benefit from such slow-light propagation. Unfortunately, the inevitable presence of disorder, imperfections, and a finite Q value may heavily affect the otherwise attractive properties of CROWs. We show how finite a Q factor limits the maximum attainable group delay time; the group index is limited by Q, but equally important the feasible device length is itself also limited by damping resulting from a finite Q. Adding the additional effects of disorder to this picture, limitations become even more severe due to destructive interference phenomena, eventually in the form of Anderson localization. Simple analytical considerations demonstrate that the maximum attainable delay time in CROWs is limited by the intrinsic photon lifetime of a single resonator.
Mechanical detection of electron spin resonance beyond 1 THz
Takahashi, Hideyuki [Organization of Advanced Science and Technology, Kobe University, 1-1, Rokkodai, Nada, Kobe 657-8501 (Japan); Ohmichi, Eiji [Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan); Ohta, Hitoshi [Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan)
2015-11-02
We report the cantilever detection of electron spin resonance (ESR) in the terahertz (THz) region. This technique mechanically detects ESR as a change in magnetic torque that acts on the cantilever. The ESR absorption of a tiny single crystal of Co Tutton salt, Co(NH{sub 4}){sub 2}(SO{sub 4}){sub 2}⋅6H{sub 2}O, was observed in frequencies of up to 1.1 THz using a backward travelling wave oscillator as a THz-wave source. This is the highest frequency of mechanical detection of ESR till date. The spectral resolution was evaluated with the ratio of the peak separation to the sum of the half-width at half maximum of two absorption peaks. The highest resolution value of 8.59 ± 0.53 was achieved at 685 GHz, while 2.47 ± 0.01 at 80 GHz. This technique will not only broaden the scope of ESR spectroscopy application but also lead to high-spectral-resolution ESR imaging.
All-electrical nonlinear fano resonance in coupled quantum point contacts
Xiao, Shiran
This thesis is motivated by recent interest in the Fano resonance (FR). As a wave-interference phenomenon, this resonance is of increasing importance in optics, plasmon-ics, and metamaterials, where its ability to cause rapid signal modulations under variation of some suitable parameter makes it desirable for a variety of applications. In this thesis, I focus on a novel manifestation of this resonance in systems of coupled quantum point contacts (QPCs). The major finding of this work is that the FR in this system may be ma-nipulated by applying a nonlinear DC bias to the system. Under such conditions, we are able to induce significant distortions of resonance lineshape, providing a pathway to all-electrical manipulation of the FR. To interpret this behavior we apply a recently-developed model for a three-path FR, involving an additional "intruder" continuum. We have previously used this model to account for the magnetic-field induced distortions of the FR observed in coupled QPCs, and show here that this model also provides a frame-work for understanding the observed nonlinear behavior. Our work therefore reveals a new manifestation of the FR that can be sensitively tailored by external control, a finding that may eventually allow the application of this feature to nanoelectronics. Since the in-terference scheme involves in this thesis is a completely general one, it should be broadly applicable across a variety of different wave-based systems, including those in both pho-tonics and electronics and opening up the possibility of new applications in areas such as chemical and biological sensing and secure communications.
Tuning the resonance properties of 2D carbon nanotube networks towards a mechanical resonator
Zhan, Haifei; Zhang, Guiyong; Zhang, Baocheng; Bell, John M.; Gu, Yuantong
2015-08-01
The capabilities of the mechanical resonator-based nanosensors in detecting ultra-small mass or force shifts have driven a continuing exploration of the palette of nanomaterials for such application purposes. Based on large-scale molecular dynamics simulations, we have assessed the applicability of a new class of carbon nanomaterials for nanoresonator usage, i.e. the single-wall carbon nanotube (SWNT) network. It is found that SWNT networks inherit excellent mechanical properties from the constituent SWNTs, possessing a high natural frequency. However, although a high quality factor is suggested from the simulation results, it is hard to obtain an unambiguous Q-factor due to the existence of vibration modes in addition to the dominant mode. The nonlinearities resulting from these extra vibration modes are found to exist uniformly under various testing conditions including different initial actuations and temperatures. Further testing shows that these modes can be effectively suppressed through the introduction of axial strain, leading to an extremely high quality factor in the order of 109 estimated from the SWNT network with 2% tensile strain. Additional studies indicate that the carbon rings connecting the SWNTs can also be used to alter the vibrational properties of the resulting network. This study suggests that the SWNT network can be a good candidate for applications as nanoresonators.
Study of Intrinsic Dissipation Due to Thermoelastic Coupling in Gyroscope Resonators.
Li, Changlong; Gao, Shiqiao; Niu, Shaohua; Liu, Haipeng
2016-01-01
This paper presents analytical models, as well as numerical and experimental verification of intrinsic dissipation due to thermoelastic loss in tuning-fork resonator. The thermoelastic analytical governing equations are created for resonator vibrating at drive-mode and sense-mode, and thermoelastic vibration field quantities are deduced. Moreover, the theoretical values are verified that coincided well with finite element analysis (FEM) simulation results. Also, the comparison of vibration field quantities is made to investigate the effect of different conditions on resonator thermoelastic vibration behavior. The significant parameters of thermoelastic damping and quality factor are subsequently deduced to analyze the energy dissipation situation in the vibration process. Meanwhile, the corresponding conclusions from other studies are used to verify our theoretical model and numerical results. By comparing with the experimental quality factor, the numerical values are validated. The combination of the theoretical expressions, numerical results and experimental data leads to an important insight into the achievable quality factor value of tuning-fork resonator, namely, that the thermoelastic damping is the main loss mechanism in the micro-comb finger structure and the quality factor varies under different vibration modes. The results demonstrate that the critical geometry dimensions of tuning-fork resonator can be well designed with the assistance of this study.
Relaxation of a Quantum Emitter Resonantly Coupled to a Metal Nanoparticle
Nerkararyan, Khachatur V
2013-01-01
Presence of a metal nanoparticle near a quantum dipole emitter, when a localized surface plasmon mode is excited via the resonant coupling with an excited quantum dipole, changes dramatically the relaxation dynamics: it is no longer described by an exponential decay but exhibits step-like behavior. The main physical consequence of this relaxation process is that the emission, being largely determined by the metal nanoparticle, comes out with a substantial delay. A large number of system parameters in our analytical description opens new possibilities for controlling quantum emitter dynamics.
WU Shao-Quan; SUN Wei-Li
2007-01-01
Using the Keldysh Nonequilibrium Green function and equation-of-motion technique,we investigate Fano versus Kondo resonances in closed Aharonov-Bohm interferometer coupled to ferromagnetic leads and study their effects on the conductance of this system.The conductance with both parallel and antiparallel lead-polarization alignments is analysed for various values of the magnetic flux.Our results show that this system can provide an excellent spin filtering property,and a large tunnelling magnetoresistance can arise by adjusting the system parameters,which indicates that this system is a possible candidate for spin valve transistors and has important applications in spintronics.
Theory of Electro-optic Modulation via a Quantum Dot Coupled to a Nano-resonator
Majumdar, Arka; Faraon, Andrei; Vuckovic, Jelena
2009-01-01
In this paper, we analyze the performance of an electro-optic modulator based on a single quantum dot strongly coupled to a nano-resonator, where electrical control of the quantum dot frequency is achieved via quantum confined Stark effect. Using realistic system parameters, we show that modulation speeds of a few tens of GHz are achievable with this system, while the energy per switching operation can be as small as 0.5 fJ. In addition, we study the non-linear distortion, and the effect of pure quantum dot dephasing on the performance of the modulator.
Aharonov-Bohm Oscillations and Fano Resonance of a Coupled Dot-Ring System
XIONG Yong-Jian
2006-01-01
@@ We derive an exact expression for the transmission coefficient through an Aharonov-Bohm ring with a side-coupled quantum dot using the scattering-matrix approach. We show a sudden AB phase change by π as the quantum dot is tuned across the resonance. The Aharonov-Bohm oscillation amplitude can be modulated effectively by tuning the quantum dot level. The transmission coefficient has an expression of the generalized Fano form with a complex Fano parameter q in the presence of the Aharonov-Bohm flux.
Relaxation dynamics of a quantum emitter resonantly coupled to a metal nanoparticle
Nerkararyan, K. V.; Bozhevolnyi, S. I.
2014-01-01
The presence of a metal nanoparticle (MNP) near a quantum dipole emitter, when a localized surface plasmon mode is excited via the resonant coupling with an excited quantum dipole, dramatically changes the relaxation dynamics: an exponential decay changes to step-like behavior. The main physical...... consequence of this relaxation process is that the emission, being largely determined by the MNP, comes out with a substantial delay. A large number of system parameters in our analytical description opens new possibilities for controlling quantum emitter dynamics. (C) 2014 Optical Society of America...
Qian, Min; Zhang, Xue-Juan
2002-03-01
This article investigates the influence of noise in a two-dimensional square array of coupled nonlinear oscillators without periodic driving. Array enhanced stochastic resonance under global as well as local noise perturbation is shown to exist under a crucial condition: the value of the rotation number of the deterministic system being zero. Meanwhile, the stochastic synchronization phenomenon is displayed in a wide range of noise intensity whether noise is added globally or locally. Furthermore, for every oscillator, the peak frequency is shown to agree with the rotation number much better than in the uncoupled system.
Hiroyuki Kamano
2012-04-01
We review a global analysis of meson production reactions off the nucleons by a collaboration at Excited Baryon Analysis Center of Jefferson Lab. The analysis is pursued with a dynamical coupled-channels approach, within which the dynamics of multi-channel reaction processes are taken into account in a fully consistent way with the two-body as well as three-body unitarity of the S-matrix. With this approach, new features of nucleon excitations are revealed as resonant particles originating from the non-trivial multi-channel reaction dynamics, which cannot be addressed by static hadron models where the nucleon excitations are treated as stable particles.
Shigehiro Hashimoto
2009-10-01
Full Text Available An inductively coupled wireless coil for a radio frequency (RF probe has been designed and applied to a human knee joint to improve the signal to noise ratio (SNR in a magnetic resonance image (MRI. A birdcage type of a primary coil and a Helmholtz type of a wireless secondary coil have been manufactured. The coils were applied to a human knee with a 3 T MRI system. SNR was calculated both in the proton density image and in the T2 weighted image of MRI. The experimental results show that the designed coils are effective to increase SNR in the human knee MRI.
Coupled-mode induced transparency in aerostatically-tuned microbubble whispering gallery resonators
Yang, Yong; Ward, Jonathan; Chormaic, Síle Nic
2015-01-01
Coupled-mode induced transparency is realized in a single microbubble whispering gallery mode resonator. Using aerostatic tuning, we find that the pressure induced shifting rates are different for different radial order modes. A finite element simulation considering both the strain and stress effects shows a GHz/bar difference and this is confirmed by experiments. A transparency spectrum is obtained when a first order mode shifts across a higher order mode through precise pressure tuning. The resulting lineshapes are fitted with the theory. This work lays a foundation for future applications in microbubble sensing.
Evidence of Resonant Mode Coupling in the Hot B Subdwarf Star KIC 10139564
Zong W.
2015-01-01
Full Text Available The Kepler spacecraft provides new opportinuties to observe long term frequency and amplitude modulations of oscillation modes in pulsating stars. We analyzed more than three years of uninterrupted data obtained with this instrument on the hot B subdwarf (sdB star KIC 10139564 and found clear signatures of nonlinear resonant mode coupling affecting several multiplets. The observed periodic frequency and amplitude modulations may allow for new asteroseismic diagnostics, providing in particular ways to measure linear growth rates of pulsation modes in hot subdwarf stars for the first time.
3D magnetic-resonance-coupling (MRC) localization of wireless capsule endoscopy
Xia, Yongming; Zhang, Lihui; Lu, Kaiyuan
2016-01-01
Wireless Capsule Endoscope (WCE) enables developing actively controlled capsule for potential complex surgeries, imaging, and new medicine tests. These tasks of WCE need safe, efficient, and precise 3D localization techniques. In this paper, a new application of the magnetic resonance coupling (MRC......) technique, which has been widely developed for efficient wireless power transfer, is introduced. It is proposed that the distance dependent signal strength in a MRC system can be beneficially used for 3D localization. The new 3D-MRC localization system consists of three orthogonal emitting coils which...
An intrinsically safe mechanism for physically coupling humans with robots.
O'Neill, Gerald; Patel, Harshil; Artemiadis, Panagiotis
2013-06-01
Robots are increasingly used in tasks that include physical interaction with humans. Examples can be found in the area of rehabilitation robotics, power augmentation robots, as well as assistive and orthotic devices. However, current methods of physically coupling humans with robots fail to provide intrinsic safety, adaptation and efficiency, which limit the application of wearable robotics only to laboratory and controlled environments. In this paper we present the design and verification of a novel mechanism for physically coupling humans and robots. The device is intrinsically safe, since it is based on passive, non-electric features that are not prone to malfunctions. The device is capable of transmitting forces and torques in all directions between the human user and the robot. Moreover, its re-configurable nature allows for easy and consistent adjustment of the decoupling force. The latter makes the mechanism applicable to a wide range of human-robot coupling applications, ranging from low-force rehabilitation-therapy scenarios to high-force augmentation cases.
Song, Wan-Lu; Yang, Wan-Li; Yin, Zhang-Qi; Chen, Chang-Yong; Feng, Mang
2016-09-01
We explore controllable quantum dynamics of a hybrid system, which consists of an array of mutually coupled superconducting resonators (SRs) with each containing a nitrogen-vacancy center spin ensemble (NVE) in the presence of inhomogeneous broadening. We focus on a three-site model, which compared with the two-site case, shows more complicated and richer dynamical behavior, and displays a series of damped oscillations under various experimental situations, reflecting the intricate balance and competition between the NVE-SR collective coupling and the adjacent-site photon hopping. Particularly, we find that the inhomogeneous broadening of the spin ensemble can suppress the population transfer between the SR and the local NVE. In this context, although the inhomogeneous broadening of the spin ensemble diminishes entanglement among the NVEs, optimal entanglement, characterized by averaging the lower bound of concurrence, could be achieved through accurately adjusting the tunable parameters.
Qiao, Yan; Polzer, Frank; Kirmse, Holm; Steeg, Egon; Kühn, Sergei; Friede, Sebastian; Kirstein, Stefan; Rabe, Jürgen P
2015-02-24
Resonant coupling between distinct excitons in organic supramolecular assemblies and inorganic semiconductors is supposed to offer an approach to optoelectronic devices. Here, we report on colloidal nanohybrids consisting of self-assembled tubular J-aggregates decorated with semiconductor quantum dots (QDs) via electrostatic self-assembly. The role of QDs in the energy transfer process can be switched from a donor to an acceptor by tuning its size and thereby the excitonic transition energy while keeping the chemistry unaltered. QDs are located within a close distance (energy transfer coupling, which is around 92% in the case of energy transfer from the QD donor to the J-aggregate acceptor and approximately 20% in the reverse case. This system provides a model of an organic-inorganic light-harvesting complex using methods of self-assembly in aqueous solution, and it highlights a route toward hierarchical synthesis of structurally well-defined supramolecular objects with advanced functionality.
Thermo-mechanical coupled analysis of hot ring rolling process
SUN Zhi-chao; YANG He; OU Xin-zhe
2008-01-01
A 3D rigid-plastic and coupled thermo-mechanical FE model for hot ring rolling(HRR) was developed based on DEFORM 3D software, then coupled heat transferring, material flow and temperature distribution of the ring in HRR were simulated and the effects of process parameters on them were analyzed. The results show that the deformation nonuniformity of ring blank increases with the increase of the rotational speed of driver roll and friction factor or the decrease of the feed rate of idle roll and initial temperature of ring blank. The temperature nonuniformity of ring blank decreases with the increase of the feed rate of idle roll or the decrease of initial temperature of ring blank and friction factor. There is an optimum rotational speed of driver roll under which the temperature distribution of ring blank is the most uniform. The results obtained can provide a guide for forming parameters optimization and quality control.
A photonic analog of Möbius strips using coupled optical ring resonators
Wu, Li-Ting; Guo, Rui-Peng; Cui, Tie-Jun; Chen, Jing
2017-02-01
A Möbius strip has an intriguing topological property in that it only has one non-orientable side. Here we propose to utilize coupled optical ring resonators (ORRs) to simulate the topological effect of Möbius strips. This scheme is based on the fact that the counter-clockwise mode in an ORR only couples to the clockwise mode of an adjacent ORR. We show that if an odd number of ORRs form a closed loop, after a round trip the handedness of the excited mode does not return to the initial one. Only after a double round trip does the mode come back to its initial state. Such a kind of Möbius-type coupling topology can be observed from the strong backward reflection in a common bus that provides the initial excitation. Eigenmodes, reflection and transmission spectra, and field distributions are calculated and analyzed. We also study the situation without Möbius-type coupling. The difference between these two categories is discussed. COMSOL simulations verify our analysis. The importance of this investigation and potential applications are briefly discussed.
Feshbach Resonance due to Coherent {lambda}-{sigma} Coupling in {sup 7}{sub {lambda}}He
Mon, San San; Nwe, Tin Tin [Department of Physics, Mandalay University (Myanmar); Myint, Khin Swe [Pro-Rector, Mandalay University (Myanmar)], E-mail: pro-rector@mptmail.net.mm; Akaishi, Y. [College of Science and Technology, Nihon University, Chiba, Japan and RIKEN Nishina Center, Saitama (Japan)
2010-04-01
Coherent {lambda}-{sigma} coupling effect in {sup 7}{sub {lambda}}He is analyzed within three-body framework of two coupled channels, {lambda}-t-t and {sigma}-{tau}-t, where {tau} represents trinulceon which is either {sup 3}H or {sup 3}He. The hyperon-trinucleon (Y{tau}) and trinucleon-trinucleon ({tau}{tau}) interactions are derived by folding G-matrices of YN and NN interactions with trinucleon density distributions. It is found that the binding energy of {sup 7}{sub {lambda}}He is 4.04 MeV below the {lambda}+t+t threshold without {lambda}-{sigma} coupling and the binding energy is increased to 4.46 MeV when the coupling effect is included. This state is 7.85 MeV above the {sup 6}He+{lambda} threshold and it may have a chance to be observed as a Feshbach resonance in {sup 7}Li (e,e{sup '}K{sup +}){sup 7}{sub {lambda}}He experiment done at Jefferson Lab.
Spin-orbit-induced strong coupling of a single spin to a nanomechanical resonator
Palyi, Andras [University of Konstanz (Germany); Eoetvoes University, Budapest (Hungary); Struck, Philipp R.; Burkard, Guido [University of Konstanz (Germany); Rudner, Mark [Harvard University, Cambridge, Massachusetts (United States); Flensberg, Karsten [Harvard University, Cambridge, Massachusetts (United States); Niels Bohr Institute, Copenhagen (Denmark)
2012-07-01
We theoretically investigate the coupling of electron spin to vibrational motion due to curvature-induced spin-orbit coupling in suspended carbon nanotube quantum dots. Our estimates indicate that, with current capabilities, a quantum dot with an odd number of electrons can serve as a realization of the Jaynes-Cummings model of quantum electrodynamics in the strong-coupling regime. A quantized flexural mode of the suspended tube plays the role of the optical mode and we identify two distinct two-level subspaces, at small and large magnetic field, which can be used as qubits in this setup. The strong intrinsic spin-mechanical coupling allows for detection, as well as manipulation of the spin qubit, and may yield enhanced performance of nanotubes in sensing applications.
Vibrational modes of ultrathin carbon nanomembrane mechanical resonators
Zhang, Xianghui, E-mail: zhang@physik.uni-bielefeld.de, E-mail: elke.scheer@uni-konstanz.de; Angelova, Polina; Gölzhäuser, Armin [Fakultät für Physik, Universität Bielefeld, 33615 Bielefeld (Germany); Waitz, Reimar; Yang, Fan; Lutz, Carolin; Scheer, Elke, E-mail: zhang@physik.uni-bielefeld.de, E-mail: elke.scheer@uni-konstanz.de [Fachbereich Physik, Universität Konstanz, 78457 Konstanz (Germany)
2015-02-09
We report measurements of vibrational mode shapes of mechanical resonators made from ultrathin carbon nanomembranes (CNMs) with a thickness of approximately 1 nm. CNMs are prepared from electron irradiation induced cross-linking of aromatic self-assembled monolayers and the variation of membrane thickness and/or density can be achieved by varying the precursor molecule. Single- and triple-layer freestanding CNMs were made by transferring them onto Si substrates with square/rectangular orifices. The vibration of the membrane was actuated by applying a sinusoidal voltage to a piezoelectric disk on which the sample was glued. The vibrational mode shapes were visualized with an imaging Mirau interferometer using a stroboscopic light source. Several mode shapes of a square membrane can be readily identified and their dynamic behavior can be well described by linear response theory of a membrane with negligible bending rigidity. By applying Fourier transformations to the time-dependent surface profiles, the dispersion relation of the transverse membrane waves can be obtained and its linear behavior verifies the membrane model. By comparing the dispersion relation to an analytical model, the static stress of the membranes was determined and found to be caused by the fabrication process.
H∞ Loop shaping control for PLL-based mechanical resonance tracking in NEMS resonant mass sensors
Kharrat, Chady; Colinet, Eric; Voda, Alina
2008-01-01
International audience; Abstract--A simple dynamic detection of the resonance frequency shift in NEMS resonant mass sensors is described. This is done without the use of an external frequency sweep signal nor a frequency counter limiting the dynamic variation detection. Neither an amplitude control nor a phase switcher is required for maintaining the resonant oscillations. The sensor is driven directly by the VCO's output for which the control signal is calculated by a robust H∞ controller us...
Two mode coupling in a single ion oscillator via parametric resonance
Gorman, Dylan J; Selvarajan, Sankaranarayanan; Daniilidis, Nikos; Häffner, Hartmut
2014-01-01
Atomic ions, confined in radio-frequency Paul ion traps, are a promising candidate to host a future quantum information processor. In this letter, we demonstrate a method to couple two motional modes of a single trapped ion, where the coupling mechanism is based on applying electric fields rather than coupling the ion's motion to a light field. This reduces the design constraints on the experimental apparatus considerably. As an application of this mechanism, we cool a motional mode close to its ground state without accessing it optically. As a next step, we apply this technique to measure the mode's heating rate, a crucial parameter determining the trap quality. In principle, this method can be used to realize a two-mode quantum parametric amplifier.
Quantum and classical control of single photon states via a mechanical resonator
Basiri-Esfahani, Sahar; Myers, Casey R.; Combes, Joshua; Milburn, G. J.
2016-06-01
Optomechanical systems typically use light to control the quantum state of a mechanical resonator. In this paper, we propose a scheme for controlling the quantum state of light using the mechanical degree of freedom as a controlled beam splitter. Preparing the mechanical resonator in non-classical states enables an optomechanical Stern-Gerlach interferometer. When the mechanical resonator has a small coherent amplitude it acts as a quantum control, entangling the optical and mechanical degrees of freedom. As the coherent amplitude of the resonator increases, we recover single photon and two-photon interference via a classically controlled beam splitter. The visibility of the two-photon interference is particularly sensitive to coherent excitations in the mechanical resonator and this could form the basis of an optically transduced weak-force sensor.
Franchi, A; Vanbavinkhove, G; CERN. Geneva. BE Department
2010-01-01
In this note we show how to compute the Resonance Driving Term (RDT) f1001, the local resonance term chi 1010 and the coupling coefficient C from the spectrum of turn-by-turn single-BPM data. The harmonic analysis of real coordinate x(y) is model independent, conversely to the the analysis of the complex Courant-Snyder coordinate hx,- = x-ipx. From the computation of f1001 along the ring is closely related to the global coupling coefficient C, but it is affected by an intrinsic error, discussed in this note.
Yan, Yiying; Lü, Zhiguo; Zheng, Hang
2016-08-01
We present a theoretical formalism for resonance fluorescence radiating from a two-level system (TLS) driven by any periodic driving and coupled to multiple reservoirs. The formalism is derived analytically based on the combination of Floquet theory and Born-Markov master equation. The formalism allows us to calculate the spectrum when the Floquet states and quasienergies are analytically or numerically solved for simple or complicated driving fields. We can systematically explore the spectral features by implementing the present formalism. To exemplify this theory, we apply the unified formalism to comprehensively study a generic model that a harmonically driven TLS is simultaneously coupled to a radiative reservoir and a dephasing reservoir. We demonstrate that the significant features of the fluorescence spectra, the driving-induced asymmetry and the dephasing-induced asymmetry, can be attributed to the violation of detailed balance condition, and explained in terms of the driving-related transition quantities between Floquet-states and their steady populations. In addition, we find the distinguished features of the fluorescence spectra under the biharmonic and multiharmonic driving fields in contrast with that of the harmonic driving case. In the case of the biharmonic driving, we find that the spectra are significantly different from the result of the RWA under the multiple resonance conditions. By the three concrete applications, we illustrate that the present formalism provides a routine tool for comprehensively exploring the fluorescence spectrum of periodically strongly driven TLSs.
Yan, Yiying, E-mail: yiyingyan@sjtu.edu.cn; Lü, Zhiguo, E-mail: zglv@sjtu.edu.cn; Zheng, Hang, E-mail: hzheng@sjtu.edu.cn
2016-08-15
We present a theoretical formalism for resonance fluorescence radiating from a two-level system (TLS) driven by any periodic driving and coupled to multiple reservoirs. The formalism is derived analytically based on the combination of Floquet theory and Born–Markov master equation. The formalism allows us to calculate the spectrum when the Floquet states and quasienergies are analytically or numerically solved for simple or complicated driving fields. We can systematically explore the spectral features by implementing the present formalism. To exemplify this theory, we apply the unified formalism to comprehensively study a generic model that a harmonically driven TLS is simultaneously coupled to a radiative reservoir and a dephasing reservoir. We demonstrate that the significant features of the fluorescence spectra, the driving-induced asymmetry and the dephasing-induced asymmetry, can be attributed to the violation of detailed balance condition, and explained in terms of the driving-related transition quantities between Floquet-states and their steady populations. In addition, we find the distinguished features of the fluorescence spectra under the biharmonic and multiharmonic driving fields in contrast with that of the harmonic driving case. In the case of the biharmonic driving, we find that the spectra are significantly different from the result of the RWA under the multiple resonance conditions. By the three concrete applications, we illustrate that the present formalism provides a routine tool for comprehensively exploring the fluorescence spectrum of periodically strongly driven TLSs.
Strong Coupling of a Donor Spin Ensemble to a Volume Microwave Resonator
Rose, Brendon; Tyryshkin, Alexei; Lyon, Stephen
We achieve the strong coupling regime between an ensemble of phosphorus donor spins (5e13 total donors) in highly enriched 28-Si (50 ppm 29-Si) and a standard dielectric resonator. Spins were polarized beyond Boltzmann equilibrium to a combined electron and nuclear polarization of 120 percent using spin selective optical excitation of the no-phonon bound exciton transition. We observed a spin ensemble-resonator splitting of 580 kHz (2g) in a cavity with a Q factor of 75,000 (κ loss rates respectively). The spin ensemble has a long dephasing time (9 μs) providing a wide window for viewing the time evolution of the coupled spin ensemble-cavity system described by the Tavis-Cummings model The free induction decay shows repeated collapses and revivals revealing a coherent and complete exchange of excitations between the superradiant state of the spin ensemble and the cavity (about 10 cycles are resolved). This exchange can be viewed as a swap of information between a long lived spin ensemble memory qubit (T2 ~ 2 ms) and a cavity
Schmidt, C.; Lloret Fuentes, E.; Buchholz, M.
2015-11-01
Wireless Power Transfer (WPT) with simultaneous data transmission through coupled magnetic resonators is investigated in this paper. The development of this system is dedicated to serve as a basis for applications in the field of Ambient Assisted Living (AAL), for example tracking vital parameters remotely, charge and control sensors and so on. Due to these different scenarios we consider, it is important to have a system which is reliable under the circumstance of changing positioning of the receiving device. State of the art radio systems would be able to handle this. Nevertheless, energy harvesting from far field sources is not sufficient to power the devices additionally on mid-range distances. For this reason, coupled magnetic resonant circuits are proposed as a promising alternative, although suffering from more complex positioning dependency. Based on measurements on a simple prototype system, an equivalent circuit description is used to model the transmission system dependent on different transmission distances and impedance matching conditions. Additionally, the simulation model is used to extract system parameters such as coupling coefficients, coil resistance and self-capacitance, which cannot be calculated in a simple and reliable way. Furthermore, a mathematical channel model based on the schematic model has been built in MATLAB©. It is used to point out the problems occurring in a transmission system with variable transmission distance, especially the change of the passband's centre frequency and its bandwidth. Existing solutions dealing with this distance dependent behaviour, namely the change of the transmission frequency dependent on distance and the addition of losses to the resonators to increase the bandwidth, are considered as not inventive. First, changing the transmission frequency increases the complexity in the data transmission system and would use a disproportional total bandwidth compared to the actually available bandwidth
Liu, Yu-Long; Wu, Rebing; Zhang, Jing; Özdemir, Şahin Kaya; Yang, Lan; Nori, Franco; Liu, Yu-xi
2017-01-01
We theoretically study a strongly driven optomechanical system which consists of a passive optical cavity and an active mechanical resonator. When the optomechanical coupling strength is varied, phase transitions, which are similar to those observed in PT -symmetric systems, are observed. We show that the optical transmission can be controlled by changing the gain of the mechanical resonator and loss of the optical cavity mode. Especially, we find that (i) for balanced gain and loss, optical amplification and absorption can be tuned by changing the optomechanical coupling strength through a control field; (ii) for unbalanced gain and loss, even with a tiny mechanical gain, both optomechanically induced transparency and anomalous dispersion can be observed around a critical point, which exhibits an ultralong group delay. The time delay τ can be optimized by regulating the optomechanical coupling strength through the control field, and it can be improved up to several orders of magnitude (τ ˜2 ms ) compared to that of conventional optomechanical systems (τ ˜1 μ s ). The presence of mechanical gain makes the group delay more robust to environmental perturbations. Our proposal provides a powerful platform to control light transport using a PT -symmetric-like optomechanical system.
Dynamical coupled-channels model for neutrino-induced meson productions in resonance region
Nakamura, S X; Sato, T
2015-01-01
A dynamical coupled-channels (DCC) model for neutrino-nucleon reactions in the resonance region is developed. Starting from the DCC model that we have previously developed through an analysis of $\\pi N, \\gamma N\\to \\pi N, \\eta N, K\\Lambda, K\\Sigma$ reaction data for $W\\le 2.1$ GeV, we extend the model of the vector current to $Q^2\\le$ 3.0 (GeV/$c$)$^2$ by analyzing electron-induced reaction data for both proton and neutron targets. We derive axial-current matrix elements that are related to the $\\pi N$ interactions of the DCC model through the Partially Conserved Axial Current (PCAC) relation. Consequently, the interference pattern between resonant and non-resonant amplitudes is uniquely determined. We calculate cross sections for neutrino-induced meson productions, and compare them with available data. Our result for the single-pion production reasonably agrees with the data. We also make a comparison with the double-pion production data. Our model is the first DCC model that can give the double-pion product...
Selective mode coupling in microring resonators for single mode semiconductor lasers
Arbabi, Amir
Single mode semiconductor laser diodes have many applications in optical communications, metrology and sensing. Edge-emitting single mode lasers commonly use distributed feedback structures, or narrowband reflectors such as distributed Bragg reflectors (DBRs) and sampled grating distributed Bragg reflectors (SGDBRs). Compact, narrowband reflectors with high reflectivities are of interest to replace the commonly used DBRs and SGDBRs. This thesis presents our work on the simulation, design, fabrication, and characterization of devices operating based on the coupling of degenerate modes of a microring resonator, and investigation of the possibility of using them for improving the performance of laser diodes. In particular, we demonstrate a new type of compact, narrowband, on-chip reflector realized by selectively coupling degenerate modes of a microring resonator. For the simulation and design of reflective microring resonators, a fast and accurate analysis method is required. Conventional numerical methods for solving Maxwell's equations such as the finite difference time domain and the finite element method (FEM) provide accurate results but are computationally intense and are not suitable for the design of large 3D structures. We formulated a set of coupled mode equations that, combined with 2D FEM simulations, can provide a fast and accurate tool for the modeling and design of reflective microrings. We developed fabrication processing recipes and fabricated passive reflective microrings on silicon substrates with a silicon nitride core and silicon dioxide cladding. Narrowband single wavelength reflectors were realized which are 70 times smaller than a conventional DBR with the same bandwidth. Compared to the conventional DBR, they have faster roll-off, and no side modes. The smaller footprint saves real estate, reduces tuning power and makes these devices attractive as in-line mirrors for low threshold narrow linewidth laser diodes. Self-heating caused by material
Chloroform alters interleaflet coupling in lipid bilayers: an entropic mechanism
Reigada, Ramon; Sagués, Francesc
2015-01-01
The interaction of the two leaflets of the plasmatic cell membrane is conjectured to play an important role in many cell processes. Experimental and computational studies have investigated the mechanisms that modulate the interaction between the two membrane leaflets. Here, by means of coarse-grained molecular dynamics simulations, we show that the addition of a small and polar compound such as chloroform alters interleaflet coupling by promoting domain registration. This is interpreted in terms of an entropic gain that would favour frequent chloroform commuting between the two leaflets. The implication of this effect is discussed in relation to the general anaesthetic action. PMID:25833246
Simoes, Fernando; Pfaff, Robert; Berthelier, Jean-Jacques; Klenzing, Jeffrey
2012-01-01
Investigation of coupling mechanisms between the troposphere and the ionosphere requires a multidisciplinary approach involving several branches of atmospheric sciences, from meteorology, atmospheric chemistry, and fulminology to aeronomy, plasma physics, and space weather. In this work, we review low frequency electromagnetic wave propagation in the Earth-ionosphere cavity from a troposphere-ionosphere coupling perspective. We discuss electromagnetic wave generation, propagation, and resonance phenomena, considering atmospheric, ionospheric and magnetospheric sources, from lightning and transient luminous events at low altitude to Alfven waves and particle precipitation related to solar and magnetospheric processes. We review in situ ionospheric processes as well as surface and space weather phenomena that drive troposphere-ionosphere dynamics. Effects of aerosols, water vapor distribution, thermodynamic parameters, and cloud charge separation and electrification processes on atmospheric electricity and electromagnetic waves are reviewed. We also briefly revisit ionospheric irregularities such as spread-F and explosive spread-F, sporadic-E, traveling ionospheric disturbances, Trimpi effect, and hiss and plasma turbulence. Regarding the role of the lower boundary of the cavity, we review transient surface phenomena, including seismic activity, earthquakes, volcanic processes and dust electrification. The role of surface and atmospheric gravity waves in ionospheric dynamics is also briefly addressed. We summarize analytical and numerical tools and techniques to model low frequency electromagnetic wave propagation and solving inverse problems and summarize in a final section a few challenging subjects that are important for a better understanding of tropospheric-ionospheric coupling mechanisms.
Data mechanics and coupling geometry on binary bipartite networks.
Hsieh Fushing
Full Text Available We quantify the notion of pattern and formalize the process of pattern discovery under the framework of binary bipartite networks. Patterns of particular focus are interrelated global interactions between clusters on its row and column axes. A binary bipartite network is built into a thermodynamic system embracing all up-and-down spin configurations defined by product-permutations on rows and columns. This system is equipped with its ferromagnetic energy ground state under Ising model potential. Such a ground state, also called a macrostate, is postulated to congregate all patterns of interest embedded within the network data in a multiscale fashion. A new computing paradigm for indirect searching for such a macrostate, called Data Mechanics, is devised by iteratively building a surrogate geometric system with a pair of nearly optimal marginal ultrametrics on row and column spaces. The coupling measure minimizing the Gromov-Wasserstein distance of these two marginal geometries is also seen to be in the vicinity of the macrostate. This resultant coupling geometry reveals multiscale block pattern information that characterizes multiple layers of interacting relationships between clusters on row and on column axes. It is the nonparametric information content of a binary bipartite network. This coupling geometry is then demonstrated to shed new light and bring resolution to interaction issues in community ecology and in gene-content-based phylogenetics. Its implied global inferences are expected to have high potential in many scientific areas.
Coupling of a nano mechanical oscillator and an atomic three-level medium
Sanz-Mora, A; Wüster, S; Rost, J -M
2015-01-01
We theoretically investigate the coupling of an ultracold three-level atomic gas and a nano-mechanical mirror via classical electromagnetic radiation. The radiation pressure on the mirror is modulated by absorption of a probe light field, caused by the atoms which are electromagnetically rendered nearly transparent, allowing the gas to affect the mirror. In turn, the mirror can affect the gas as its vibrations generate opto-mechanical sidebands in the control field. We show that the sidebands cause modulations of the probe intensity at the mirror frequency, which can be enhanced near atomic resonances. Through the radiation pressure from the probe beam onto the mirror, this results in resonant driving of the mirror. Controllable by the two photon detuning, the phase relation of the driving to the mirror motion decides upon amplification or damping of mirror vibrations. This permits direct phase locking of laser amplitude modulations to the motion of a nano-mechanical element opening a perspective for cavity-f...
Nonlinear interaction of meta-atoms through optical coupling
Slobozhanyuk, A. P.; Kapitanova, P. V.; Filonov, D. S.; Belov, P. A. [National Research University of Information Technologies, Mechanics and Optics (ITMO), St. Petersburg 197101 (Russian Federation); Powell, D. A. [Nonlinear Physics Centre and Centre for Ultrahigh-bandwidth Devices for Optical Systems (CUDOS), Australian National University, Canberra, ACT 0200 (Australia); Shadrivov, I. V.; Kivshar, Yu. S. [National Research University of Information Technologies, Mechanics and Optics (ITMO), St. Petersburg 197101 (Russian Federation); Nonlinear Physics Centre and Centre for Ultrahigh-bandwidth Devices for Optical Systems (CUDOS), Australian National University, Canberra, ACT 0200 (Australia); Lapine, M., E-mail: mlapine@physics.usyd.edu.au [National Research University of Information Technologies, Mechanics and Optics (ITMO), St. Petersburg 197101 (Russian Federation); Centre for Ultrahigh-bandwidth Devices for Optical Systems (CUDOS), School of Physics, University of Sydney, New South Wales 2006 (Australia); McPhedran, R. C. [Centre for Ultrahigh-bandwidth Devices for Optical Systems (CUDOS), School of Physics, University of Sydney, New South Wales 2006 (Australia)
2014-01-06
We propose and experimentally demonstrate a multi-frequency nonlinear coupling mechanism between split-ring resonators. We engineer the coupling between two microwave resonators through optical interaction, whilst suppressing the direct electromagnetic coupling. This allows for a power-dependent interaction between the otherwise independent resonators, opening interesting opportunities to address applications in signal processing, filtering, directional coupling, and electromagnetic compatibility.
Livings, R. A.; Dayal, V.; Barnard, D. J.; Hsu, D. K.
2012-05-01
Ceramic tiles are the main ingredient of a multi-material, multi-layered composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. Defects in the tile, during manufacture or after usage, are expected to change the resonance frequencies and resonance images of the tile. The comparison of the resonance frequencies and resonance images of a pristine tile/lay-up to a defective tile/lay-up will thus be a quantitative damage metric. By examining the vibrational behavior of these tiles and the composite lay-up with Finite Element Modeling and analytical plate vibration equations, the development of a new Nondestructive Evaluation technique is possible. This study examines the development of the Air-Coupled Ultrasonic Resonance Imaging technique as applied to a hexagonal ceramic tile and a multi-material, multi-layered composite.
Thermal-mechanical coupled effect on fracture mechanism and plastic characteristics of sandstone
ZUO; JianPing; XIE; HePing; ZHOU; HongWei; PENG; SuPing
2007-01-01
Scanning electronic microscopy (SEM) was employed to investigate fractographs of sandstone in mine roof strata under thermal-mechanical coupled effect. Based on the evolution of sandstone surface morphology in the failure process and fractography, the fracture mechanism was studied and classified under meso and micro scales, respectively. The differences between fractographs under different temperatures were examined in detail. Under high temperature, fatigue fracture and plastic deformation occurred in the fracture surface. Therefore, the temperature was manifested by these phenomena to influence strongly on micro failure mechanism of sandstone. In addition, the failure mechanism would transit from brittle failure mechanism at low temperature to coupled brittle-ductile failure mechanism at high temperature. The variation of sandstone strength under different temperature can be attributed to the occurrence of plastic deformation, fatigue fracture, and microcracking. The fatigue striations in the fracture surfaces under high temperature may be interpreted as micro fold. And the coupled effect of temperature and tensile stress may be another formation mechanism of micro fold in geology.
Mechanical threshold as a factor in excitation-contraction coupling.
Taylor, S R; Preiser, H; Sandow, A
1969-09-01
I(-), CH(3)SO(4) (-), and ClO(4) (-), like other previously studied type A twitch potentiators (Br(-), NO(3) (-), SCN(-), and caffeine), lower the mechanical threshold in K depolarization contractures of frog skeletal muscle. In potentiated twitches, I(-), Br(-), CH(3)SO(4) (-), ClO(4), and SCN, as already reported for NO(3) (-) and caffeine, slightly shorten the latent period (L) and considerably increase the rate of tension development (dP/dt) during the first few milliseconds of the contraction period. Divalent cations (8 mM Ca(2+), 0.5-1.0 mM Zn(2+) and Cd(2+)) raise the mechanical threshold of contractures, and correspondingly affect the twitch by depressing the tension output, increasing L, and decreasing the early dP/dt, thus acting oppositely to the type A potentiators. These various results form a broad, consistent pattern indicating that electromechanical coupling in the twitch is conditioned by a mechanical threshold as it is in the contracture, and suggesting that the lower the threshold, in reference to the raised threshold under the action of the divalent cations, the more effective is a given action potential in activating the twitch as regards especially both its early rate and peak magnitude of tension development. The results suggest that the direct action by which the various agents affect the level of the mechanical threshold involves effects on E-C coupling processes of the T tubular and/or the sarcoplasmic reticulum which control the release of Ca for activating contraction.
Liu Cheng
2016-01-01
Full Text Available ANSYS can be a powerful tool to simulate the process of energy exchange in magnetically-coupled resonant wireless power transfer system. In this work, the MCR-WPT system with single intermediate coil resonator is simulated and researched based on scattering parameters using ANSYS Electromagnetics. The change rule of power transfer efficiency is reflected intuitively through the scattering parameters. A new method of calculating the coupling coefficient is proposed. A cascaded 2-port network model using scattering parameters is adopted to research the efficiency of transmission. By changing the relative position and the number of turns of the intermediate coil, we find some factors affecting the efficiency of transmission. Methods and principles of designing the MCR-WPT system with single intermediate coil resonator are obtained. And these methods have practical value with design and optimization of system efficiency.
Mechanism of electromechanical coupling in voltage-gated potassium channels
Rikard eBlunck
2012-09-01
Full Text Available Voltage-gated ion channels play a central role in the generation of action potentials in the nervous system. They are selective for one type of ion – sodium, calcium or potassium. Voltage-gated ion channels are composed of a central pore that allows ions to pass through the membrane and four peripheral voltage sensing domains that respond to changes in the membrane potential. Upon depolarization, voltage sensors in voltage-gated potassium channels (Kv undergo conformational changes driven by positive charges in the S4 segment and aided by pairwise electrostatic interactions with the surrounding voltage sensor. Structure-function relations of Kv channels have been investigated in detail, and the resulting models on the movement of the voltage sensors now converge to a consensus; the S4 segment undergoes a combined movement of rotation, tilt and vertical displacement in order to bring 3-4 e+ each through the electric field focused in this region. Nevertheless, the mechanism by which the voltage sensor movement leads to pore opening, the electromechanical coupling, is still not fully understood. Thus, recently, electromechanical coupling in different Kv channels has been investigated with a multitude of techniques including electrophysiology, 3D crystal structures, fluorescence spectroscopy and molecular dynamics simulations. Evidently, the S4-S5 linker, the covalent link between the voltage sensor and pore, plays a crucial role. The linker transfers the energy from the voltage sensor movement to the pore domain via an interaction with the S6 C-termini, which are pulled open during gating. In addition, other contact regions have been proposed. This review aims to provide (i an in-depth comparison of the molecular mechanisms of electromechanical coupling in different Kv channels; (ii insight as to how the voltage sensor and pore domain influence one another; and (iii theoretical predictions on the movement of the cytosolic face of the KV channels
Dynamical coupled-channel model of meson production reactions in the nucleon resonance region
Matsuyama, A; Sato, T
2006-01-01
A dynamical coupled-channel model is presented for investigating the nucleon resonances in the meson production reactions induced by pions and photons. The model is based on an energy-independent Hamiltonian which is derived from a set of Lagrangians by using a unitary transformation method. By applying the projection operator techniques,we derive a set of coupled-channel equations which satisfy the unitarity conditions within the channel space spanned by the considered two-particle meson-baryon states and the three-particle $\\pi\\pi N$ state. We present and explain in detail a numerical method based on a spline-function expansion for solving the resulting coupled-channel equations which contain logarithmically divergent one-particle-exchange driving terms resulted from the $\\pi\\pi N$ unitarity cut. We show that this driving term can generate rapidly varying structure in the reaction amplitudes associated with the unstable particle channels. It also has large effects in determining the two-pion production cros...
Liu, Yimin; You, Jiabin; Hou, Qizhe
2016-02-23
Exploration of macroscopic quantum entanglement is of great interest in both fundamental science and practical application. We investigate a hybrid quantum system that consists of two nitrogen-vacancy centers ensembles (NVE) coupled to a superconducting coplanar waveguide resonator (CPWR). The collective magnetic coupling between the NVE and the CPWR is employed to generate macroscopic entanglement between the NVEs, where the CPWR acts as the quantum bus. We find that, this NVE-CPWR hybrid system behaves as a system of three coupled harmonic oscillators, and the excitation prepared initially in the CPWR can be distributed into these two NVEs. In the nondissipative case, the entanglement of NVEs oscillates periodically and the maximal entanglement always keeps unity if the CPWR is initially prepared in the odd coherent state. Considering the dissipative effect from the CPWR and NVEs, the amount of entanglement between these two NVEs strongly depends on the initial state of the CPWR, and the maximal entanglement can be tuned by adjusting the initial states of the total system. The experimental feasibility and challenge with currently available technology are discussed.
Olsson, R. H., III
2012-03-01
The goal of this project was to develop high frequency quality factor (fQ) product acoustic resonators matched to a standard RF impedance of 50 {Omega} using overmoded bulk acoustic wave (BAW) resonators. These resonators are intended to serve as filters in a chip scale mechanical RF spectrum analyzer. Under this program different BAW resonator designs and materials were studied theoretically and experimentally. The effort resulted in a 3 GHz, 50 {Omega}, sapphire overmoded BAW with a fQ product of 8 x 10{sup 13}, among the highest values ever reported for an acoustic resonator.
Failure mechanisms and electromechanical coupling in semiconducting nanowires
Peng B.
2010-06-01
Full Text Available One dimensional nanostructures, like nanowires and nanotubes, are increasingly being researched for the development of next generation devices like logic gates, transistors, and solar cells. In particular, semiconducting nanowires with a nonsymmetric wurtzitic crystal structure, such as zinc oxide (ZnO and gallium nitride (GaN, have drawn immense research interests due to their electromechanical coupling. The designing of the future nanowire-based devices requires component-level characterization of individual nanowires. In this paper, we present a unique experimental set-up to characterize the mechanical and electromechanical behaviour of individual nanowires. Using this set-up and complementary atomistic simulations, mechanical properties of ZnO nanowires and electromechanical properties of GaN nanowires were investigated. In ZnO nanowires, elastic modulus was found to depend on nanowire diameter decreasing from 190 GPa to 140 GPa as the wire diameter increased from 5 nm to 80 nm. Inconsistent failure mechanisms were observed in ZnO nanowires. Experiments revealed a brittle fracture, whereas simulations using a pairwise potential predicted a phase transformation prior to failure. This inconsistency is addressed in detail from an experimental as well as computational perspective. Lastly, in addition to mechanical properties, preliminary results on the electromechanical properties of gallium nitride nanowires are also reported. Initial investigations reveal that the piezoresistive and piezoelectric behaviour of nanowires is different from bulk gallium nitride.
The coupled bio-chemo-electro-mechanical behavior of glucose exposed arterial elastin
Zhang, Yanhang; Li, Jiangyu; Boutis, Gregory S.
2017-04-01
Elastin, the principle protein component of the elastic fiber, is a critical extracellular matrix (ECM) component of the arterial wall providing structural resilience and biological signaling essential in vascular morphogenesis and maintenance of mechanical homeostasis. Pathogenesis of many cardiovascular diseases have been associated with alterations of elastin. As a long-lived ECM protein that is deposited and organized before adulthood, elastic fibers can suffer from cumulative effects of biochemical exposure encountered during aging and/or disease, which greatly compromise their mechanical function. This review article covers findings from recent studies of the mechanical and structural contribution of elastin to vascular function, and the effects of biochemical degradation. Results from diverse experimental methods including tissue-level mechanical characterization, fiber-level nonlinear optical imaging, piezoelectric force microscopy, and nuclear magnetic resonance are reviewed. The intriguing coupled bio-chemo-electro-mechanical behavior of elastin calls for a multi-scale and multi-physical understanding of ECM mechanics and mechanobiology in vascular remodeling.
Mechanism of geometric nonlinearity in a nonprismatic and heterogeneous microbeam resonator
Asadi, Keivan; Li, Junfeng; Peshin, Snehan; Yeom, Junghoon; Cho, Hanna
2017-09-01
Implementation of geometric nonlinearity in microelectromechanical systems (MEMS) resonators offers a flexible and efficient design to overcome the limitations of linear MEMS by utilizing beneficial nonlinear characteristics not attainable in a linear setting. Integration of nonlinear coupling elements into an otherwise purely linear microcantilever is one promising way to intentionally realize geometric nonlinearity. Here, we demonstrate that a nonlinear, heterogeneous microresonator system, consisting of a silicon microcantilever with a polymer attachment exhibits strong nonlinear hardening behavior not only in the first flexural mode but also in the higher modes (i.e., second and third flexural modes). In this design, we deliberately implement a drastic and reversed change in the axial vs bending stiffness between the Si and polymer components by varying the geometric and material properties. By doing so, the resonant oscillations induce the large axial stretching within the polymer component, which effectively introduces the geometric stiffness and damping nonlinearity. The efficacy of the design and the mechanism of geometric nonlinearity are corroborated through a comprehensive experimental, analytical, and numerical (finite element) analysis on the nonlinear dynamics of the proposed system.
Shukrinov, Yu. M.; Gaafar, M. A.
2011-09-01
A manifestation of a resonance-type hysteresis related to the parametric resonance in the system of coupled Josephson junctions is demonstrated. In contrast with the McCumber and Steward hysteresis, we find that the width of this hysteresis is inversely proportional to the McCumber parameter and it also depends on the coupling between junctions and the boundary conditions. Investigation of the time dependence of the electric charge in superconducting layers allows us to explain the origin of this hysteresis by different charge dynamics for increasing and decreasing bias current processes. The effect of the wavelength of the longitudinal plasma wave created at the resonance on the charging of superconducting layers is demonstrated. We find a strong effect of the dissipation in the system on the amplitude of the charge oscillations at the resonance.
A High-order Eulerian-Lagrangian Finite Element Method for Coupled Electro-mechanical Systems
Brandstetter, Gerd
The main focus of this work is on the development of a high-order Eulerian-Lagrangian finite element method for the simulation of electro-mechanical systems. The coupled problem is solved by a staggered scheme, where the mechanical motion is discretized by standard Lagrangian finite elements, and the electrical field is solved on a fixed Eulerian grid with embedded boundary conditions. Traditional Lagrangian-Lagrangian or arbitrary Lagrangian-Eulerian (ALE) methods encounter deficiencies, for example, when dealing with mesh distortion due to large deformations, or topology changes due to contacting bodies. The presented Eulerian-Lagrangian approach addresses these issues in a natural way. Within this context we develop a high-order immersed boundary discontinuous-Galerkin (IB-DG) method, which is shown to be necessary for (i) the accurate representation of the electrical gradient along nonlinear boundary features such as singular corners, and (ii) to achieve full convergence during the iterative global solution. We develop an implicit scheme based on the mid-point rule, as well as an explicit scheme based on the centered-difference method, with the incorporation of energy conserving, frictionless contact algorithms for an elastic-to-rigid-surface contact. The performance of the proposed method is assessed for several benchmark tests: the electro-static force vector around a singular corner, the quasi-static pull-in of an electro-mechanically actuated switch, the excitation of a carbon nanotube at resonance, and the cyclic impact simulation of a micro-electro-mechanical resonant-switch. We report improved accuracy for the high-order method as compared to low-order methods, and linear convergence in the iterative solution of the staggered scheme. Additionally, we investigate a Newton-Krylov shooting scheme in order to directly find cyclic steady states of electro-mechanical devices excited at resonance-- as opposed to a naive time-stepping from zero initial
A high sensitivity humidity sensor based on micro-ring resonator with three coupling points
Guo, Shi-liang; Wang, Wen-juan; Hu, Chun-hai
2014-12-01
A novel high sensitivity humidity sensor based on micro-ring resonator with three coupling points (MRRTCP) is reported. Since the dielectric constant of Polyimide is highly sensible to the relative humidity of the environment, we choose the Polyimide (PI) as the moisture material. The effective refractive index of the sensing part of the sensor changes as the relative humidity of the environment changes, this leading to an obvious shift of the output spectrum. The sensing range of the relative humidity sensor is 0~100%RH, and the sensitivity is 0.0017μm/%RH, and the structure is relatively simple and could be used in micro-scale humidity sensing.
Coupling between Surface Plasmon Resonance and electric current in Au stripes
Garcia, Miguel Angel; Serrano, Aida; de La Venta, Jose
2009-03-01
Surface Plasmon Resonance (SPR) is the most outstanding feature of noble metal films. SPR consists on a collective oscillation of the conduction electrons when excited optically in the appropriate geometrical and energy conditions. The electrical current passing trough the metal film involves also the movement of conduction electrons. Thus, coupling effects are expected between SPR and electrical resistivity. A modification of the SPR when a electrical current passes through the film, could allow the modulation of an optical signal by a electrical one. Similarly, when the film is illuminated at the SPR conditions, the oscillation of the conduction electrons and local heating can induce an enhancement of the electric resistivity that can be used to translate an optical signal into a electric one. Those effects could be useful in the development of new fast optoelectronic transducers. We present here results on Au stripes illuminated to induce the SPR while electric currents flow with different orientation with respect to the light polarization
Kunal Tiwari
2016-04-01
Full Text Available Hafnium dioxide has been recognized as an excellent dielectric for microelectronics. However, its usefulness for the surface plasmon based sensors has not yet been tested. Here we investigate its usefulness for waveguide-coupled bi-metallic surface plasmon resonance sensors. Several Ag/HfO2/Au multilayer structure sensors were fabricated and evaluated by optical measurements and computer simulations. The resulting data establish correlations between the growth parameters and sensor performance. The sensor sensitivity to refractive index of analytes is determined to be S n = ∂ θ SPR ∂ n ≥ 4 7 0 . The sensitivity data are supported by simulations, which also predict 314 nm for the evanescent field decay length in air.
An on-chip coupled resonator optical waveguide single-photon buffer.
Takesue, Hiroki; Matsuda, Nobuyuki; Kuramochi, Eiichi; Munro, William J; Notomi, Masaya
2013-01-01
Integrated quantum optical circuits are now seen as one of the most promising approaches with which to realize single-photon quantum information processing. Many of the core elements for such circuits have been realized, including sources, gates and detectors. However, a significant missing function necessary for photonic quantum information processing on-chip is a buffer, where single photons are stored for a short period of time to facilitate circuit synchronization. Here we report an on-chip single-photon buffer based on coupled resonator optical waveguides (CROW) consisting of 400 high-Q photonic crystal line-defect nanocavities. By using the CROW, a pulsed single photon is successfully buffered for 150 ps with 50-ps tunability while maintaining its non-classical properties. Furthermore, we show that our buffer preserves entanglement by storing and retrieving one photon from a time-bin entangled state. This is a significant step towards an all-optical integrated quantum information processor.
An on-chip coupled resonator optical waveguide single-photon buffer
Takesue, Hiroki; Kuramochi, Eiichi; Munro, Willian J; Notomi, Masaya
2013-01-01
Integrated quantum optical circuits are now seen as one of the most promising approaches with which to realize single photon quantum information processing. Many of the core elements for such circuits have been realized including sources, gates and detectors. However, a significant missing function necessary for photonic information processing on-chip is a buffer, where single photons are stored for a short period of time to facilitate circuit synchronization. Here we report an on-chip single photon buffer based on coupled resonator optical waveguides (CROW) consisting of 400 high-Q photonic crystal line defect nanocavities. By using the CROW, a pulsed single photon was successfully buffered for 150 ps with 50-ps tunability while maintaining its non-classical properties. Furthermore, we showed that our buffer preserves entanglement by storing and retrieving one photon from a time-bin entangled state. This is a significant step towards an all-optical integrated quantum information processor.
Anil Kumar; K V Ramanathan; T S Mahesh; Neeraj Sinha; K V R Murali
2002-08-01
Use of dipolar and quadrupolar couplings for quantum information processing (QIP) by nuclear magnetic resonance (NMR) is described. In these cases, instead of the individual spins being qubits, the 2 energy levels of the spin-system can be treated as an -qubit system. It is demonstrated that QIP in such systems can be carried out using transition-selective pulses, in CH3CN, 13CH3CN, 7Li ( = 3/2) and 133Cs ( = 7/2), oriented in liquid crystals yielding 2 and 3 qubit systems. Creation of pseudopure states, implementation of logic gates and arithmetic operations (half-adder and subtractor) have been carried out in these systems using transition-selective pulses.
Photoassociation of Trilobite Rydberg Molecules via Resonant Spin-Orbit Coupling
Kleinbach, K. S.; Meinert, F.; Engel, F.; Kwon, W. J.; Löw, R.; Pfau, T.; Raithel, G.
2017-06-01
We report on a novel method for the photoassociation of strongly polar trilobite Rydberg molecules. This exotic ultralong-range dimer, consisting of a ground-state atom bound to the Rydberg electron via electron-neutral scattering, inherits its polar character from the admixture of high-angular-momentum electronic orbitals. The absence of low-L character hinders standard photoassociation techniques. Here, we show that for suitable principal quantum numbers the resonant coupling of the orbital motion with the nuclear spin of the perturber, mediated by electron-neutral scattering, hybridizes the trilobite molecular potential with the more conventional S -type molecular state. This provides a general path to associate trilobite molecules with large electric dipole moments, as demonstrated via high-resolution spectroscopy. We find a dipole moment of 135(45) D for the trilobite state. Our results are compared to theoretical predictions based on a Fermi model.
Entanglement of resonantly coupled field modes in cavities with vibrating boundaries
Andreata, M A; Dodonov, V V
2002-01-01
We study time dependence of various measures of entanglement (covariance entanglement coefficient, purity entanglement coefficient, normalized distance coefficient, entropic coefficients) between resonantly coupled modes of the electromagnetic field in ideal cavities with oscillating boundaries. Two types of cavities are considered: a three-dimensional cavity possessing eigenfrequencies $\\omega_3=3\\omega_1$, whose wall oscillates at the frequency $\\omega_w=2\\omega_1$, and a one-dimensional (Fabry--Perot) cavity with an equidistant spectrum $\\omega_n= n\\omega_1$, when the distance between perfect mirrors oscillates at the frequencies $\\omega_1$ and $2\\omega_1$. The behaviour of entanglement measures in these cases turns out to be completely different, although all three coefficients demonstrate qualitatively similar time dependences in each case (except for some specific situations, where the covariance entanglement coefficient, based on traces of covariance submatrices, seems to be essentially more sensitive ...
Bistable Output from a Coupled-Resonator Vertical-Cavity Laser Diode
FISCHER,ARTHUR J.; CHOQUETTE,KENT D.; CHOW,WENG W.; ALLERMAN,ANDREW A.; GEIB,KENT M.
2000-07-20
The authors report a monolithic coupled-resonator vertical-cavity laser with an ion-implanted top cavity and a selectively oxidized bottom cavity which exhibits bistable behavior in the light output versus injection current. Large bistability regions over current ranges as wide as 18 mA have been observed with on/off contrast ratios of greater than 20 dB. The position and width of the bistability region can be varied by changing the bias to the top cavity. Switching between on and off states can be accomplished with changes as small as 250 {micro}W to the electrical power applied to the top cavity. Theoretical analysis suggests that the bistable behavior is the response of the nonlinear susceptibility in the top cavity to the changes in the bottom intracavity laser intensity as the bottom cavity reaches the thermal rollover point.
Electron spin resonance in a two-dimensional Fermi liquid with spin-orbit coupling
Maiti, Saurabh; Imran, Muhammad; Maslov, Dmitrii L.
2016-01-01
Electron spin resonance (ESR) is usually viewed as a single-particle phenomenon protected from the effect of many-body correlations. We show that this is not the case in a two-dimensional Fermi liquid (FL) with spin-orbit coupling (SOC). Depending on whether the in-plane magnetic field is below or above some critical value, ESR in such a system probes up to three chiral-spin collective modes, augmented by the spin mode in the presence of the field, or the Silin-Leggett mode. All the modes are affected by both SOC and FL renormalizations. We argue that ESR can be used as a probe not only for SOC but also for many-body physics.
A Refractive Index Sensor Based on the Resonant Coupling to Cladding Modes in a Fiber Loop
Reyes, Mauricio; Monzón-Hernández, David; Martínez-Ríos, Alejandro; Silvestre, Enrique; Díez, Antonio; Cruz, José Luis; Andrés, Miguel V.
2013-01-01
We report an easy-to-build, compact, and low-cost optical fiber refractive index sensor. It consists of a single fiber loop whose transmission spectra exhibit a series of notches produced by the resonant coupling between the fundamental mode and the cladding modes in a uniformly bent fiber. The wavelength of the notches, distributed in a wavelength span from 1,400 to 1,700 nm, can be tuned by adjusting the diameter of the fiber loop and are sensitive to refractive index changes of the external medium. Sensitivities of 170 and 800 nm per refractive index unit for water solutions and for the refractive index interval 1.40–1.442, respectively, are demonstrated. We estimate a long range resolution of 3 × 10−4 and a short range resolution of 2 × 10−5 for water solutions. PMID:23979478
A Bose-Einstein condensate coupled to a nanomechanical resonator on an atom chip
Treutlein, P; Hunger, D; Hänsch, T W; Reichel, J; Camerer, Stephan; H\\"ansch, Theodor W.; Hunger, David; Reichel, Jakob; Treutlein, Philipp
2007-01-01
We study the coupling of the spin of Bose-Einstein condensed atoms to the mechanical oscillations of a nanoscale cantilever with a magnetic tip. This is an experimentally viable hybrid quantum system which allows one to explore the interface of quantum optics and condensed matter physics. We propose an experiment where easily detectable atomic spin-flips are induced by the cantilever motion. This can be used to probe thermal oscillations of the cantilever with the atoms. At low cantilever temperatures, as realized in recent experiments, back-action of the atoms onto the cantilever is significant and the system represents a mechanical analog of cavity quantum electrodynamics. With high but realistic cantilever quality factors, the strong coupling regime can be reached, either with single atoms or collectively with BECs. We discuss an implementation on an atom chip.
Coupling of electrical and mechanical switching in nanoscale ferroelectrics
Cao, Ye; Li, Qian; Chen, Long-Qing; Kalinin, Sergei V.
2015-11-01
While electric field induced ferroelectric switching has been extensively studied and broadly utilized, pure mechanical switching via flexoelectric effect has recently opened up an alternative method for domain writing due to their highly localized, electrically erasable and electric damage free characteristics. Thus far, few studies have been made on the coupling effect of electro-mechanical switching in ferroelectric materials, likely due to the experimental difficulty in the accurate definition of the tip-surface contact area and in the identification of mechanical contribution from electrical effect. Here, we employed self-consistent phase-field modeling to investigate the bi-polar switching behavior of (001) oriented Pb(Zr0.2Ti0.8)O3 thin film under concurrent electric and strain field created via a piezoresponse force microscope probe. By separating the effects from electric field, homogeneous strain and strain gradient, we revealed that the homogeneous strain suppresses the spontaneous polarization and accordingly increases the coercive field, and the strain gradient favors unipolar switching and inhibit it in the reverse direction, thus causing lateral offset of the hysteresis loop. The uncertainty of flexoelectric coefficients and the influence of flexocoupling coefficients on switching have also been discussed. Our study could necessitate further understanding of the electric, piezoelectric, and flexoelectric contribution to the switching behavior in nanoscale ferroelectric oxides.
Chung, Y. D.; Lee, S. Y.; Lee, T. W.; Kim, J. S. [Suwon Science College, Suwon (Korea, Republic of); Lee, C. Y. [Korea Railroad Institute, Uiwang (Korea, Republic of)
2016-03-15
The technology of supplying the electric power by wireless power transfer (WPT) is expected for the next generation power feeding system since it can supply the power to portable devices without any connectors through large air gap. As such a technology based on strongly coupled electromagnetic resonators is possible to deliver the large power and recharge them seamlessly; it has been considered as a noble option to wireless power charging system in the various power applications. Recently, various HTS wires have now been manufactured for demonstrations of transmission cables, motors, MAGLEV, and other electrical power components. However, since the HTS magnets have a lower index n value intrinsically, they are required to be charged from external power system through leads or internal power system. The portable area is limited as well as the cryogen system is bulkier. Thus, we proposed a novel design of wireless power charging system for superconducting HTS magnet (WPC4SM) based on resonance coupling method. As the novel system makes possible a wireless power charging using copper resonance coupled coils, it enables to portable charging conveniently in the superconducting applications. This paper presented the conceptual design and operating characteristics of WPC4SM using different shapes' copper resonance coil. The proposed system consists of four components; RF generator of 370 kHz, copper resonance coupling coils, impedance matching (IM) subsystem and HTS magnet including rectifier system.
Theoretical Study on the Mechanism of Sonogashira Coupling Reaction
CHEN Li-Ping; HONG San-Guo; HOU Hao-Qing
2008-01-01
The mechanism of palladium-catalyzed Sonogashira cross-coupling reaction has been studied theoretically by DFT (density functional theory) calculations. The model system studied consists of Pd(PH3)2 as the starting catalyst complex, phenyl bromide as the substrate and acetylene as the terminal alkyne, without regarding to the co-catalyst and base. Mechanistically and energetically plausible catalytic cycles for the cross-coupling have been identified. The DFT analysis shows that the catalytic cycle occurs in three stages: oxidative addition of phenyl bromide to the palladium center, alkynylation of palladium(II) intermediate, and reductive elimination to phenylacetylene. In the oxidative addition, the neutral and anionic pathways have been investigated, which could both give rise to cis-configured palladium(II) diphosphine intermediate. Starting from the palladium(II) diphosphine intermediate, the only identifiable pathway in alkynylation involves the dissociation of Br group and the formation of square-planar palladium(II) intermediate, in which the phenyl and alkynyl groups are oriented cis to each other. Due to the close proximity of phenyl and alkynyl groups, the reductive elimination of phenylacetylene proceeds smoothly.
Dantan, Aurélien; Marler, Joan; Albert, Magnus
2010-01-01
We report on a novel noninvasive method to determine the normal mode frequencies of ion Coulomb crystals in traps based on the resonance enhanced collective coupling between the electronic states of the ions and an optical cavity field at the single photon level. Excitations of the normal modes...... are observed through a Doppler broadening of the resonance. An excellent agreement with the predictions of a zero-temperature uniformly charged liquid plasma model is found. The technique opens up for investigations of the heating and damping of cold plasma modes, as well as the coupling between them....
Design and Modelling of a Two-port Surface Acoustic WaveResonator using Coupling-of-modes Theory
Mamta Khaneja
2008-05-01
Full Text Available In this present paper the coupling-of-modes theory has been used to design and simulatethe characteristics of a two-port SAW resonator with shorted reflection gratings to define theresonance cavity. A resonator device at 150 MHz has been designed and fabricated on ST-Quartz. It is found that the simulated and experimental characteristics of the device are in closeagreement. The results show that the SAW designs based on coupling-of-modes formulationare adequate for most applications.
Jorgensen, Rasmus; Holliday, Nicholas D; Hansen, Jakob L
2007-01-01
To analyze the interaction between the neurokinin-1 (NK-1) receptor and G-protein coupled receptor kinases (GRKs), we performed bioluminescence resonance energy transfer(2) (BRET(2)) measurements between the family A NK-1 receptor and GRK2 and GRK5 as well as their respective kinase-inactive muta......To analyze the interaction between the neurokinin-1 (NK-1) receptor and G-protein coupled receptor kinases (GRKs), we performed bioluminescence resonance energy transfer(2) (BRET(2)) measurements between the family A NK-1 receptor and GRK2 and GRK5 as well as their respective kinase...
Backbone resonance assignment and order tensor estimation using residual dipolar couplings
Shealy, Paul; Liu, Yizhou; Simin, Mikhail
2014-01-01
An NMR investigation of proteins with known X-ray structures is of interest in a number of endeavors. Performing these studies through nuclear magnetic resonance (NMR) requires the costly step of resonance assignment. The prevalent assignment strategy does not make use of existing structural information and requires uniform isotope labeling. Here we present a rapid and cost-effective method of assigning NMR data to an existing structure—either an X-ray or computationally modeled structure. The presented method, Exhaustively Permuted Assignment of RDCs (EPAR), utilizes unassigned residual dipolar coupling (RDC) data that can easily be obtained by NMR spectroscopy. The algorithm uses only the backbone N–H RDCs from multiple alignment media along with the amino acid type of the RDCs. It is inspired by previous work from Zweckstetter and provides several extensions. We present results on 13 synthetic and experimental datasets from 8 different structures, including two homodimers. Using just two alignment media, EPAR achieves an average assignment accuracy greater than 80%. With three media, the average accuracy is higher than 94%. The algorithm also outputs a prediction of the assignment accuracy, which has a correlation of 0.77 to the true accuracy. This prediction score can be used to establish the needed confidence in assignment accuracy. PMID:21667298
Estep, Nicholas A.; Sounas, Dimitrios L.; Soric, Jason; Alù, Andrea
2014-12-01
Non-reciprocal components, which are essential to many modern communication systems, are almost exclusively based on magneto-optical materials, severely limiting their applicability. A practical and inexpensive route to magnetic-free non-reciprocity could revolutionize radio-frequency and nanophotonic communication networks. Angular-momentum biasing was recently proposed as a means of realizing isolation for sound waves travelling in a rotating medium, and envisaged as a path towards compact, linear integrated non-reciprocal electromagnetic components. Inspired by this concept, here we demonstrate a subwavelength, linear radio-frequency non-reciprocal circulator free from magnetic materials and bias. The scheme is based on the parametric modulation of three identical, strongly and symmetrically coupled resonators. Their resonant frequencies are modulated by external signals with the same amplitude and a relative phase difference of 120°, imparting an effective electronic angular momentum to the system. We observe giant non-reciprocity, with up to six orders of magnitude difference in transmission for opposite directions. Furthermore, the device topology is tunable in real time, and can be directly embedded in a conventional integrated circuit.
Signal enhancement in cantilever magnetometry based on a co-resonantly coupled sensor
Körner, Julia; Reiche, Christopher F; Gemming, Thomas; Büchner, Bernd; Gerlach, Gerald
2016-01-01
Summary Cantilever magnetometry is a measurement technique used to study magnetic nanoparticles. With decreasing sample size, the signal strength is significantly reduced, requiring advances of the technique. Ultrathin and slender cantilevers can address this challenge but lead to increased complexity of detection. We present an approach based on the co-resonant coupling of a micro- and a nanometer-sized cantilever. Via matching of the resonance frequencies of the two subsystems we induce a strong interplay between the oscillations of the two cantilevers, allowing for a detection of interactions between the sensitive nanocantilever and external influences in the amplitude response curve of the microcantilever. In our magnetometry experiment we used an iron-filled carbon nanotube acting simultaneously as nanocantilever and magnetic sample. Measurements revealed an enhancement of the commonly used frequency shift signal by five orders of magnitude compared to conventional cantilever magnetometry experiments with similar nanomagnets. With this experiment we do not only demonstrate the functionality of our sensor design but also its potential for very sensitive magnetometry measurements while maintaining a facile oscillation detection with a conventional microcantilever setup. PMID:27547621
Plasmon-coupled resonance energy transfer: A real-time electrodynamics approach.
Ding, Wendu; Hsu, Liang-Yan; Schatz, George C
2017-02-14
This paper presents a new real-time electrodynamics approach for determining the rate of resonance energy transfer (RET) between two molecules in the presence of plasmonic or other nanostructures (inhomogeneous absorbing and dispersive media). In this approach to plasmon-coupled resonance energy transfer (PC-RET), we develop a classical electrodynamics expression for the energy transfer matrix element which is evaluated using the finite-difference time-domain (FDTD) method to solve Maxwell's equations for the electric field generated by the molecular donor and evaluated at the position of the molecular acceptor. We demonstrate that this approach yields RET rates in homogeneous media that are in precise agreement with analytical theory based on quantum electrodynamics (QED). In the presence of gold nanoparticles, our theory shows that the long-range decay of the RET rates can be significantly modified by plasmon excitation, with rates increased by as much as a factor of 10(6) leading to energy transfer rates over hundreds of nm that are comparable to that over tens of nm in the absence of the nanoparticles. These promising results suggest important future applications of the PC-RET in areas involving light harvesting or sensing, where energy transfer processes involving inhomogeneous absorbing and dispersive media are commonplace.
Wadop Ngouongo, Y. J.; Djuidjé Kenmoé, G.; Kofané, T. C.
2017-04-01
This work presents the characterization of stochastic resonance (SR) and stochastic antiresonance (SAR) in terms of hysteresis loop area (HLA). In connection with SR and SAR phenomena, we study the dynamics of a chain of particles coupled by nonlinear springs in a periodic sinusoidal potential. The dependence of the coupling parameter as well as the system size on SR and SAR is analysed. We consider the role played by the nonlinear coupling on the SR. We show that there is a range of coupling parameter where only SAR is observed, after this range the SR can occur, however, there also exists a range where neither SAR nor SR appear. It is noted that the maximum and the minimum of the average input energy increases with the coupling parameter. Also demonstrate that there exists an optimal value of the number of particles N for which the average input energy of the first particle reaches the saturation.