A mirrorless spinwave resonator
Pinel, Olivier; Everett, Jesse L.; Hosseini, Mahdi; Campbell, Geoff T.; Buchler, Ben C.; Lam, Ping Koy
2015-01-01
Optical resonance is central to a wide range of optical devices and techniques. In an optical cavity, the round-trip length and mirror reflectivity can be chosen to optimize the circulating optical power, linewidth, and free-spectral range (FSR) for a given application. In this paper we show how an atomic spinwave system, with no physical mirrors, can behave in a manner that is analogous to an optical cavity. We demonstrate this similarity by characterising the build-up and decay of the resonance in the time domain, and measuring the effective optical linewidth and FSR in the frequency domain. Our spinwave is generated in a 20 cm long Rb gas cell, yet it facilitates an effective FSR of 83 kHz, which would require a round-trip path of 3.6 km in a free-space optical cavity. Furthermore, the spinwave coupling is controllable enabling dynamic tuning of the effective cavity parameters. PMID:26655839
Tunable resonant and non-resonant interactions between a phase qubit and LC resonator
NASA Astrophysics Data System (ADS)
Allman, Michael Shane; Whittaker, Jed D.; Castellanos-Beltran, Manuel; Cicak, Katarina; da Silva, Fabio; Defeo, Michael; Lecocq, Florent; Sirois, Adam; Teufel, John; Aumentado, Jose; Simmonds, Raymond W.
2014-03-01
We use a flux-biased radio frequency superconducting quantum interference device (rf SQUID) with an embedded flux-biased direct current (dc) SQUID to generate strong resonant and non-resonant tunable interactions between a phase qubit and a lumped-element resonator. The rf-SQUID creates a tunable magnetic susceptibility between the qubit and resonator providing resonant coupling rates from zero to near the ultra-strong coupling regime. By modulating the magnetic susceptibility, non-resonant parametric coupling achieves rates > 100 MHz . Nonlinearity of the magnetic susceptibility also leads to parametric coupling at subharmonics of the qubit-resonator detuning. Controllable coupling is generically important for constructing coupled-mode systems ubiquitous in physics, useful for both, quantum information architectures and quantum simulators. This work supported by NIST and NSA grant EAO140639.
Stochastic resonance on a circle
Wiesenfeld, K. ); Pierson, D.; Pantazelou, E.; Dames, C.; Moss, F. )
1994-04-04
We describe a new realization of stochastic resonance, applicable to a broad class of systems, based on an underlying excitable dynamics with deterministic reinjection. A simple but general theory of such single-trigger'' systems is compared with analog simulations of the Fitzhugh-Nagumo model, as well as experimental data obtained from stimulated sensory neurons in the crayfish.
A tunable electromechanical Helmholtz resonator
NASA Astrophysics Data System (ADS)
Liu, Fei
Acoustic liners are used in turbofan engine nacelles for the suppression of engine noise. For a given engine, there are different optimum impedance distributions associated with take-off, cut-back, and approach flight conditions. The impedance of conventional acoustic liners is fixed for a given geometry, and conventional active liner approaches are impractical. This project addresses the need for a tunable impedance through the development of an electromechanical Helmholtz resonator (EMHR). The device consists of a Helmholtz resonator with the standard rigid backplate replaced by a compliant piezoelectric composite. Analytical models (i.e., a lumped element model (LEM) and a transfer matrix (TM) representation of the EMHR) are developed to predict the acoustic behavior of the EMHR. The EMHR is experimentally investigated using the standard two-microphone method (TMM). The measurement results validate both the LEM and the TM of the EMHR. Good agreement between predicted and measured impedance is obtained. Short- and open-circuit loads define the limits of the tuning range using resistive and capacitive loads. There is approximately a 9% tuning limit under these conditions for the non-optimized resonator configuration studied. Inductive shunt loads result in a 3 degree-of-freedom (DOF) system and an enhanced tuning range of over 47% that is not restricted by the short- and open-circuit limits. Damping coefficient measurements for a piezoelectric backplate in a vacuum chamber are performed and indicate that the damping is dominated by structural damping losses. A Pareto optimization design based on models of the EMHR is performed with non-inductive loads. The EMHR with non-inductive loads has 2DOF and two resonant frequencies. The tuning ranges of the two resonant frequencies of the EMHR with non-inductive loads cannot be optimized simultaneously, so a trade-off (Pareto solution) must be reached. The Pareto solution shows how design trade-offs can be used to satisfy
Magnetic resonance force detection using a membrane resonator
NASA Astrophysics Data System (ADS)
Scozzaro, N.; Ruchotzke, W.; Belding, A.; Cardellino, J.; Blomberg, E. C.; McCullian, B. A.; Bhallamudi, V. P.; Pelekhov, D. V.; Hammel, P. C.
2016-10-01
The availability of compact, low-cost magnetic resonance imaging instruments would further broaden the substantial impact of this technology. We report highly sensitive detection of magnetic resonance using low-stress silicon nitride (SiNx) membranes. We use these membranes as low-loss, high-frequency mechanical oscillators and find they are able to mechanically detect spin-dependent forces with high sensitivity enabling ultrasensitive magnetic resonance detection. The high force detection sensitivity stems from their high mechanical quality factor Q ∼106 [1,2] combined with the low mass of the resonator. We use this excellent mechanical force sensitivity to detect the electron spin magnetic resonance using a SiNx membrane as a force detector. The demonstrated force sensitivity at 300 K is 4 fN/√{Hz } , indicating a potential low temperature (4 K) sensitivity of 25 aN/√{Hz } . Given their sensitivity, robust construction, large surface area and low cost, SiNx membranes can potentially serve as the central component of a compact room-temperature ESR and NMR instrument having spatial resolution superior to conventional approaches.
A silicon microelectromechanical resonant gyroscope
NASA Astrophysics Data System (ADS)
Wang, Yingying; Fan, Shangchun; Ren, Jie; Guo, Zhanshe
2006-11-01
This paper presents recent work on the design of a silicon microelectromechanical resonant gyroscope, and also describes the detailed principle of operation and simulation results with Matlab. The structure consists of comb drive actuators, a plate proof mass, lever mechanisms and double-ended tuning forks (DETF). The plate proof mass is driven by the comb drive actuators, and if an external rotation is applied, the Coriolis force acting on it is transmitted to the lever mechanisms attached. The lever mechanisms amplify the periodic force prior to being communicated axially onto the two symmetrical DETFs to provide a differential output. By demodulating the oscillators' frequency output, the rotation rate can then be estimated. This new design has several advantages including high sensitivity, high resolution and a quasi-digital FM output. Simulations include tests of the scale factor of the sensor and the resonant frequency of the DETF oscillators as a function of beam geometric parameters and the applied force.
A MEMS diamond hemispherical resonator
NASA Astrophysics Data System (ADS)
Bernstein, J. J.; Bancu, M. G.; Cook, E. H.; Chaparala, M. V.; Teynor, W. A.; Weinberg, M. S.
2013-12-01
In this paper we report the fabrication of hemispherical polycrystalline diamond resonators fabricated on a novel high-temperature glass substrate. The hemispherical resonator gyroscope is one of the most accurate and rugged of the mechanical gyroscopes, and can be operated in either rate or whole-angle mode due to its high degree of symmetry. A fabrication sequence for creating extremely symmetric 3D MEMS hemispheres is presented. Mode shapes and frequencies obtained with a laser vibrometer are shown, as well as curves of Q versus pressure, and the dependence of frequency on anchor size. Fundamental mode frequency matching to <0.1% in as-fabricated devices has been achieved, which is essential to gyroscope operation in whole-angle mode.
Traces of a triboson resonance
NASA Astrophysics Data System (ADS)
Aguilar-Saavedra, J. A.; Collins, J. H.; Lombardo, S.
2016-09-01
We show that the relatively small but coincident excesses observed around 2 TeV in the ATLAS Run 1 and Run 2 hadronic diboson searches — when a cut on the number of tracks in the fat jets is not applied — and the null results of all remaining high-mass diboson searches are compatible with the decay of a triboson resonance R into WZ plus an extra particle X. These decays can take place via new neutral ( Y 0) or charged ( Y ±) particles, namely R → Y 0 W, with Y 0 → ZX, or R → Y ± Z, with Y ± → WX. An obvious candidate for such intermediate particle is a neutral one Y 0, given a 3 .9 σ excess found at 650 GeV by the CMS Collaboration in searches for intermediate mass diboson resonances decaying to ZV, with V = W, Z. We discuss discovery strategies for triboson resonances with small modifications of existing hadronic searches.
NASA Astrophysics Data System (ADS)
Karpeshin, F. F.
2002-11-01
Main principles of the resonance effect arising in the electron shells in interaction of the nuclei with electromagnetic radiation are analyzed and presented in the historical aspect. Principles of NEET are considered from a more general position, as compared to how this is usually presented. Characteristic features of NEET and its reverse, TEEN, as internal conversion processes are analyzed, and ways are offered of inducing them by laser radiation. The ambivalent role of the Pauli exclusion principles in NEET and TEEN processes is investigated.
Observation of a Hybrid Spin Resonance
NASA Astrophysics Data System (ADS)
Bai, M.; Allgower, C.; Ahrens, L.; Alessi, J.; Brown, K.; Bunce, G.; Cameron, P.; Chu, C. M.; Courant, E. D.; Glenn, J. W.; Huang, H.; Jeon, D.; Kponou, A. E.; Krueger, K.; Luccio, A.; Makdisi, Y. I.; Lee, S. Y.; Ratner, L.; Reece, K.; Roser, T.; Spinka, H.; Syphers, M. J.; Tsoupas, N.; Underwood, D. G.; van Asselt, W.; Williams, N.; Yokosawa, A.
2000-02-01
A new type of spin depolarization resonance has been observed at the Brookhaven Alternating Gradient Synchrotron (AGS). This spin resonance is identified as a strong closed-orbit sideband around the dominant intrinsic spin resonance. The strength of the resonance was proportional to the 9th harmonic component of the horizontal closed orbit and proportional to the vertical betatron oscillation amplitude. This ``hybrid'' spin resonance cannot be overcome by the partial snake at the AGS, but it can be corrected by the harmonic orbit correctors.
Observation of a hybrid spin resonance
Bai; Allgower; Ahrens; Alessi; Brown; Bunce; Cameron; Chu; Courant; Glenn; Huang; Jeon; Kponou; Krueger; Luccio; Makdisi; Lee; Ratner; Reece; Roser; Spinka; Syphers; Tsoupas; Underwood; van Asselt W; Williams
2000-02-07
A new type of spin depolarization resonance has been observed at the Brookhaven Alternating Gradient Synchrotron (AGS). This spin resonance is identified as a strong closed-orbit sideband around the dominant intrinsic spin resonance. The strength of the resonance was proportional to the 9th harmonic component of the horizontal closed orbit and proportional to the vertical betatron oscillation amplitude. This "hybrid" spin resonance cannot be overcome by the partial snake at the AGS, but it can be corrected by the harmonic orbit correctors.
MAGNETIC RESONANCE ELASTOGRAPHY: A REVIEW
Mariappan, Yogesh K; Glaser, Kevin J; Ehman, Richard L
2011-01-01
Magnetic Resonance Elastography (MRE) is a rapidly developing technology for quantitatively assessing the mechanical properties of tissue. The technology can be considered to be an imaging-based counterpart to palpation, commonly used by physicians to diagnose and characterize diseases. The success of palpation as a diagnostic method is based on the fact that the mechanical properties of tissues are often dramatically affected by the presence of disease processes such as cancer, inflammation, and fibrosis. MRE obtains information about the stiffness of tissue by assessing the propagation of mechanical waves through the tissue with a special magnetic resonance imaging (MRI) technique. The technique essentially involves three steps: generating shear waves in the tissue,acquiring MR images depicting the propagation of the induced shear waves andprocessing the images of the shear waves to generate quantitative maps of tissue stiffness, called elastograms. MRE is already being used clinically for the assessment of patients with chronic liver diseases and is emerging as a safe, reliable and noninvasive alternative to liver biopsy for staging hepatic fibrosis. MRE is also being investigated for application to pathologies of other organs including the brain, breast, blood vessels, heart, kidneys, lungs and skeletal muscle. The purpose of this review article is to introduce this technology to clinical anatomists and to summarize some of the current clinical applications that are being pursued. PMID:20544947
A multimode electromechanical parametric resonator array
Mahboob, I.; Mounaix, M.; Nishiguchi, K.; Fujiwara, A.; Yamaguchi, H.
2014-01-01
Electromechanical resonators have emerged as a versatile platform in which detectors with unprecedented sensitivities and quantum mechanics in a macroscopic context can be developed. These schemes invariably utilise a single resonator but increasingly the concept of an array of electromechanical resonators is promising a wealth of new possibilities. In spite of this, experimental realisations of such arrays have remained scarce due to the formidable challenges involved in their fabrication. In a variation to this approach, we identify 75 harmonic vibration modes in a single electromechanical resonator of which 7 can also be parametrically excited. The parametrically resonating modes exhibit vibrations with only 2 oscillation phases which are used to build a binary information array. We exploit this array to execute a mechanical byte memory, a shift-register and a controlled-NOT gate thus vividly illustrating the availability and functionality of an electromechanical resonator array by simply utilising higher order vibration modes. PMID:24658349
A microwave dielectric resonant oscillatory circuit
NASA Astrophysics Data System (ADS)
Sigov, A. S.; Shvartsburg, A. B.
2016-07-01
Bias currents in a thin dielectric nonconducting torus are investigated, and the resonant mode of excitation of these currents is established. The similarity of the frequency spectrum of such a dielectric element to the spectra of a classical Thomson oscillatory circuit and a metamaterial with negative permittivity is demonstrated. The resonant frequency of electromagnetic oscillations of the ring dielectric circuit and magnetic and electric fields of such a circuit under resonant excitation are determined.
A Primer on Resonances in Quantum Mechanics
Rosas-Ortiz, Oscar; Fernandez-Garcia, Nicolas; Cruz y Cruz, Sara
2008-11-13
After a pedagogical introduction to the concept of resonance in classical and quantum mechanics, some interesting applications are discussed. The subject includes resonances occurring as one of the effects of radiative reaction, the resonances involved in the refraction of electromagnetic waves by a medium with a complex refractive index, and quantum decaying systems described in terms of resonant states of the energy (Gamow-Siegert functions). Some useful mathematical approaches like the Fourier transform, the complex scaling method and the Darboux transformation are also reviewed.
Coherence of magnetic resonators in a metamaterial
Hou, Yumin
2013-12-15
The coherence of periodic magnetic resonators (MRs) under oblique incidence is studied using simulations. The correlated phase of interaction including both the retardation effect and relative phase difference between two MRs is defined, and it plays a key role in the MR interaction. The correlated phase is anisotropic, as is the coherence condition. The coherence condition is the same as the Wood's anomaly and verified by the Fano resonance. This study shows that the applications of the Fano resonance of periodic MRs will become widespread owing to achieving the Fano resonance simply by tuning the incident angle.
de Voogd, J. M.; Wagenaar, J. J. T.; Oosterkamp, T. H.
2017-01-01
We calculate the change of the properties of a resonator, when coupled to a semiclassical spin by means of the magnetic field. Starting with the Lagrangian of the complete system, we provide an analytical expression for the linear response function for the motion in the case of a mechanical resonator and the current for the case of an electromagnetic resonator, thereby considering the influence of the resonator on the spin and vice versa. This analysis shows that the resonance frequency and effective dissipation factor can change significantly due to the relaxation times of the spin. We first derive this for a system consisting of a spin and mechanical resonator and thereafter apply the same calculations to an electromagnetic resonator. Moreover, the applicability of the method is generalized to a resonator coupled to two-level systems and more, providing a key to understand some of the problems of two-level systems in quantum devices. PMID:28186145
NASA Astrophysics Data System (ADS)
de Voogd, J. M.; Wagenaar, J. J. T.; Oosterkamp, T. H.
2017-02-01
We calculate the change of the properties of a resonator, when coupled to a semiclassical spin by means of the magnetic field. Starting with the Lagrangian of the complete system, we provide an analytical expression for the linear response function for the motion in the case of a mechanical resonator and the current for the case of an electromagnetic resonator, thereby considering the influence of the resonator on the spin and vice versa. This analysis shows that the resonance frequency and effective dissipation factor can change significantly due to the relaxation times of the spin. We first derive this for a system consisting of a spin and mechanical resonator and thereafter apply the same calculations to an electromagnetic resonator. Moreover, the applicability of the method is generalized to a resonator coupled to two-level systems and more, providing a key to understand some of the problems of two-level systems in quantum devices.
Capacitance Property of a Resonant Tunneling Diode
NASA Astrophysics Data System (ADS)
Sheng, Hanyu; Chua, Soo-Jin; Sinkkonen, Juha
A simple capacitance formula based on a semiclassical electron transport theory is given. The results show that the charges stored in the quantum well of a resonant tunneling diode have a considerable effect on the capacitance in the resonant region. The calculated capacitance is consistent with the experimental results.
Method for fabricating a microelectromechanical resonator
Wojciechowski, Kenneth E; Olsson, III, Roy H
2013-02-05
A method is disclosed which calculates dimensions for a MEM resonator in terms of integer multiples of a grid width G for reticles used to fabricate the resonator, including an actual sub-width L.sub.a=NG and an effective electrode width W.sub.e=MG where N and M are integers which minimize a frequency error f.sub.e=f.sub.d-f.sub.a between a desired resonant frequency f.sub.d and an actual resonant frequency f.sub.a. The method can also be used to calculate an overall width W.sub.o for the MEM resonator, and an effective electrode length L.sub.e which provides a desired motional impedance for the MEM resonator. The MEM resonator can then be fabricated using these values for L.sub.a, W.sub.e, W.sub.o and L.sub.e. The method can also be applied to a number j of MEM resonators formed on a common substrate.
The resonance energy of benzene: a revisit.
Mo, Yirong
2009-04-30
Zielinski and van Lenthe recently extended the block-localized wave function (BLW) method by introducing the resonating BLW (RBLW) method and performed test calculations on hexagonal H(6) and benzene [J. Phys. Chem. A 2008, 112, 13197]. However, the Pauling's resonance energies from their RBLW and ab initio valence bond (VB) calculations were greatly underestimated largely due to the imperfect use of either one-electron orbitals (method = delocal) or resonance structures (method = local). Whereas it has been well recognized that electronic resonance within a molecular system plays a stabilizing role, there are many indirect experimental evidences available to evaluate the resonance energy and, thus, to justify computational results. Here we used the BLW method, which can be regarded as the simplest variant of modern ab initio VB theory, to re-evaluate the resonance energy of benzene at the B3LYP level, following the original definition by Pauling and Wheland, who obtained the resonance energy "by subtracting the actual energy of the molecule in question from that of the most stable contributing structure". The computed vertical resonance energy (or quantum mechanical resonance energy) in benzene is 88.8, 92.2, or 87.9 kcal/mol with the basis sets of 6-31G(d), 6-311+G(d,p), or cc-pVTZ, respectively, while the adiabatic resonance energy (or theoretical resonance energy) is 61.4, 63.2, or 62.4 kcal/mol, exhibiting insignificant basis set dependency for moderate basis sets. In line with predictions, the geometry optimization of the elusive cyclohexatriene (i.e., the Kekule structure) with the BLW method also resulted in carbon-carbon bond lengths (e.g., 1.322 and 1.523 A with the cc-pVTZ basis set) comparable to those in ethylene or ethane.
Magnetic resonance force detection using a membrane resonator
NASA Astrophysics Data System (ADS)
Scozzaro, Nicolas; Ruchotzke, William; Belding, Amanda; Cardellino, Jeremy; Blomberg, Erick; McCullian, Brendan; Bhallamudi, Vidya; Pelekhov, Denis; Hammel, P. Chris
Silicon nitride (Si3N4) membranes are commercially-available, versatile structures that have a variety of applications. Although most commonly used as the support structure for transmission electron microscopy (TEM) studies, membranes are also ultrasensitive high-frequency mechanical oscillators. The sensitivity stems from the high quality factor Q 106 , which has led to applications in sensitive quantum optomechanical experiments. The high sensitivity also opens the door to ultrasensitive force detection applications. We report force detection of electron spin magnetic resonance at 300 K using a Si3N4 membrane with a force sensitivity of 4 fN/√{ Hz}, and a potential low temperature sensitivity of 25 aN/√{ Hz}. Given membranes' sensitivity, robust construction, large surface area and low cost, SiN membranes can potentially serve as the central component of a compact room-temperature ESR and NMR instrument that has superior spatial resolution to conventional NMR.
On a plasmon resonance in ellipsoidal nanoparticles
Oraevsky, A A; Oraevsky, Anatolii N
2002-01-31
The dependence of the plasmon resonance frequency of metal ellipsoids of revolution on their eccentricity is calculated. The plasmon resonance shifts to the red with increasing eccentricity and its intensity increases. The resonance intensity increases with decreasing the imaginary part of the dielectric constant of a metal. The plasmon resonance frequency in a suspension of randomly oriented prolate nanoparticles (with a large eccentricity) almost exactly coincides with that in a suspension of oriented particles. These features permit the efficient improvement of the sensitivity and resolving power of optoacoustic tomography by introducing prolate metal nanoparticles into the region of an object under study. The possibility of plasmon resonance narrowing by introducing metal nanoparticles into an amplifying medium is pointed out. (laser applications and other topics in quantum electronics)
A delta configured auxiliary resonant snubber inverter
Lai, J.S.; Young, R.W.; Ott, G.W. Jr.; McKeever, J.W.; Peng, F.Z. |
1995-09-01
A delta ({Delta}) configured auxiliary resonant snubber inverter is developed to overcome the voltage floating problem in a wye (Y) configured resonant snubber inverter. The proposed inverter is to connect auxiliary resonant branches between phase outputs to avoid a floating point voltage which may cause over-voltage failure of the auxiliary switches. Each auxiliary branch consists of a resonant inductor and a reverse blocking auxiliary switch. Instead of using an anti-paralleled diode to allow resonant current to flow in the reverse direction, as in the Y-configured version, the resonant branch in the {Delta}-configured version must block the negative voltage, typically done by a series diode. This paper shows single-phase and three-phase versions of {Delta}-configured resonant snubber inverters and describes in detail the operating principle of a single-phase version. The extended three-phase version is proposed with non-adjacent state space vector modulation. For hardware implementation, a single-phase 1-kW unit and a three-phase 100-kW unit were built to prove the concept. Experimental results show the superiority of the proposed topology.
Isolated resonator gyroscope with isolation trimming using a secondary element
NASA Technical Reports Server (NTRS)
Challoner, A. Dorian (Inventor); Shcheglov, Kirill V. (Inventor)
2006-01-01
The present invention discloses a resonator gyroscope including an isolated resonator. One or more flexures support the isolated resonator and a baseplate is affixed to the resonator by the flexures. Drive and sense elements are affixed to the baseplate and used to excite the resonator and sense movement of the gyroscope. In addition, at least one secondary element (e.g., another electrode) is affixed to the baseplate and used for trimming isolation of the resonator. The resonator operates such that it transfers substantially no net momentum to the baseplate when the resonator is excited. Typically, the isolated resonator comprises a proof mass and a counterbalancing plate.
de Sitter Space as a Resonance
NASA Astrophysics Data System (ADS)
Maltz, Jonathan; Susskind, Leonard
2017-03-01
A quantum mechanical formulation of de Sitter cosmological spacetimes still eludes string theory. In this Letter we conjecture a potentially rigorous framework in which the status of de Sitter space is the same as that of a resonance in a scattering process. We conjecture that transition amplitudes between certain states with asymptotically supersymmetric flat vacua contain resonant pole characteristic metastable intermediate states. A calculation employing constrained instantons illustrates this idea.
Stochastic resonance during a polymer translocation process
NASA Astrophysics Data System (ADS)
Mondal, Debasish; Muthukumar, Murugappan
We study the translocation of a flexible polymer in a confined geometry subjected to a time-periodic external drive to explore stochastic resonance. We describe the equilibrium translocation process in terms of a Fokker-Planck description and use a discrete two-state model to describe the effect of the external driving force on the translocation dynamics. We observe that no stochastic resonance is possible if the associated free-energy barrier is purely entropic in nature. The polymer chain experiences a stochastic resonance effect only in presence of an energy threshold in terms of polymer-pore interaction. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.
Modeling the acoustic excitation of a resonator
NASA Astrophysics Data System (ADS)
Mandre, Shreyas; Mahadevan, Lakshminarayanan
2007-11-01
The sounding of a beverage bottle when blown on is a familiar but very little understood phenomenon. A very similar mechanism is used by musical wind instruments, like organ pipes and flutes, for sound production. This phenomenon falls under the general umbrella of flow induced oscillations and is representative of a more generic mechanism. The modeling of this phenomenon essentially involves two components. The first is the resonator, which bears the oscillations and this component is very well understood. The resonator, however, needs an external energy input to sustain the oscillations, which is provided by the jet of air blown. The dynamics of the jet and its interaction with the resonator is the primary focus of this talk. In particular, we provide a linearized model based on first principles to explain the feedback of energy from the jet to the resonator and compare the predictions with experimental results.
NASA Astrophysics Data System (ADS)
Binfeng, Yun; Hu, Guohua; Zhang, Ruohu; Yiping, Cui
2016-05-01
A coupled plasmonic waveguide resonator system which can produce sharp and asymmetric Fano resonances was proposed and analyzed. Two Fano resonances are induced by the interactions between the narrow discrete whispering gallery modes in a plasmonic square cavity resonator and the broad spectrum of the metal-insulator-metal stub resonator. The relative peak amplitudes between the 1st and 2nd order Fano resonances can be adjusted by changing the structure parameters, such as the square cavity size, the stub size and the center-to-center distance between the square cavity and the stub resonators. And the 1st order Fano resonant peak, which is a standing-wave mode, will split into two resonant peaks (one standing-wave mode and one traveling-wave mode) when it couples with the 2nd Fano resonance. Also, the potential of the proposed Fano system as an integrated slow-light device and refractive index sensor was investigated. The results show that a maximum group index of about 100 can be realized, and a linear refractive index sensitivity of 938 nm/RIU with a figure of merit of about 1.35 × 104 can be obtained.
Method of making a quartz resonator
Vig, John R.; Filler, Raymond L.; Peters, R. Donald; Frank, James M.
1981-01-01
A quartz resonator is made from a chemically polished quartz plate. The plate is placed in an enclosure fitted with at least three mounting clips to receive the plate. The plate is secured to the clips with an electrically conductive adhesive capable of withstanding operation at 350 degrees C. The assembly is cleaned and a metallic electrode deposited onto the plate until the desired frequency is reached. The enclosure is then hermetically sealed. The resulting resonator can consistently withstand extremely high shocks.
Resonances as a Record of Planetary Migration
NASA Astrophysics Data System (ADS)
Cuk, Matija
2009-05-01
Many characteristics of extrasolar planets are often attributed to gas-disk-fueled "Type II" planetary migration (Ward 1997). Our own solar system's architecture is best explained by past planetesimal-driven migration of outer planets (Fernandez and Ip 1984). Both migration mechanisms are likely to be present to some degree in all systems. The possible effects of gas-driven migration in our solar system have been explored by Crida and Morbidelli (2007), while Thommes et al. (2006) and Morbidelli et al. (2007) studied the combined effect of both. These studies suggest that Type II migration may drive the giant planets into a resonant configuration which is stable against further orbital decay. Once the gas is gone planetesimal-driven migration can break the resonances and lead to a second episode of migration. Do the currently known exoplanets tell us anything on how widespread this scenario is? Eccentric or tidally-damped single-planet systems, as well as barely-stable systems of non-resonant eccentric planets, together paint a picture of planet-planet scattering (Rasio and Ford 1996, Barnes and Quinn 2004), which can result from migration but erases much of the evidence. However, resonant systems indicate that the last episode of migration was convergent. Despite small-number statistics, known compact two planet systems (period ratio < 4) suggest that the resonant lock is correlated with the higher total system mass. While more massive systems probably experience less planetesimal-driven migration (due to a relatively less abundant "fuel"), they could still have their resonant lock broken by limited divergent migration. Our preliminary hypothesis is that we are seeing a survival bias among the massive systems, as many of them may become unstable once the resonance is broken (Gladman 1993, Fabrycky and Murray-Clay 2008). This hypothesis can be tested by simulating the a range of resonant systems exposed to interactions with a planetesimal disk.
Stochastic resonance during a polymer translocation process
NASA Astrophysics Data System (ADS)
Mondal, Debasish; Muthukumar, M.
2016-04-01
We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.
Stochastic resonance during a polymer translocation process.
Mondal, Debasish; Muthukumar, M
2016-04-14
We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.
Fano resonances in a multimode waveguide coupled to a high-Q silicon nitride ring resonator.
Ding, Dapeng; de Dood, Michiel J A; Bauters, Jared F; Heck, Martijn J R; Bowers, John E; Bouwmeester, Dirk
2014-03-24
Silicon nitride (Si3N4) optical ring resonators provide exceptional opportunities for low-loss integrated optics. Here we study the transmission through a multimode waveguide coupled to a Si3N4 ring resonator. By coupling single-mode fibers to both input and output ports of the waveguide we selectively excite and probe combinations of modes in the waveguide. Strong asymmetric Fano resonances are observed and the degree of asymmetry can be tuned through the positions of the input and output fibers. The Fano resonance results from the interference between modes of the waveguide and light that couples resonantly to the ring resonator. We develop a theoretical model based on the coupled mode theory to describe the experimental results. The large extension of the optical modes out of the Si3N4 core makes this system promising for sensing applications.
Kinoshita, Yukinori; Li, Yanjun; Yoshimura, Satoru; Saito, Hitoshi; Sugawara, Yasuhiro
2017-10-04
The present work proposes magnetic resonance force microscopy (MRFM) based on ferromagnetic resonance (FMR) modulation of a magnetic tip using microwave transmission via a coaxial resonator instead of using conventional microwave irradiation by an external antenna. In this MRFM, the coaxial resonator is electrically connected to the magnetic cantilever tip, which enables simple implementation of FMR excitation of a magnetic tip in conventional magnetic force microscopy. The FMR frequency of the tip can be easily extracted from the reflection spectrum of a transmission line connected to the magnetic tip. The excitation of tip FMR is confirmed from the microwave frequency dependence of the mechanical response of the tip oscillation. This MRFM is effective for extracting the magnetic interaction force near a sample surface without perturbation of its sample magnetic state. Nanometer-scale imaging of magnetic domain structures on a demagnetized thin-film permanent magnet is successfully demonstrated. © 2017 IOP Publishing Ltd.
Lateral acoustic wave resonator comprising a suspended membrane of low damping resonator material
Olsson, Roy H.; El-Kady; , Ihab F.; Ziaei-Moayyed, Maryam; Branch; , Darren W.; Su; Mehmet F.,; Reinke; Charles M.,
2013-09-03
A very high-Q, low insertion loss resonator can be achieved by storing many overtone cycles of a lateral acoustic wave (i.e., Lamb wave) in a lithographically defined suspended membrane comprising a low damping resonator material, such as silicon carbide. The high-Q resonator can sets up a Fabry-Perot cavity in a low-damping resonator material using high-reflectivity acoustic end mirrors, which can comprise phononic crystals. The lateral overtone acoustic wave resonator can be electrically transduced by piezoelectric couplers. The resonator Q can be increased without increasing the impedance or insertion loss by storing many cycles or wavelengths in the high-Q resonator material, with much lower damping than the piezoelectric transducer material.
A low-power resonant micromachined compass
NASA Astrophysics Data System (ADS)
Leïchlé, Thierry C.; Von Arx, Martin; Reiman, Stephen; Zana, Iulica; Ye, Wenjing; Allen, Mark G.
2004-04-01
This paper describes a micromachined magnetic field sensor based on magnetic resonant structures. A micromechanical resonator fabricated using surface micromachining techniques is modified so as to incorporate a magnetic material. The shift of the fundamental mechanical resonant frequency of the device, caused by the interaction of the external magnetic field and the magnetic component of the resonant system, is used to determine the amplitude or the direction of the external field. We have designed, fabricated and tested two types of micromachined magnetic field sensors relying on the proposed principle of operation. The fabrication of the sensors follows CMOS-compatible and low temperature processes based on surface micromachining. Devices have been fabricated which exhibit a minimum resolution of 45° at 30 µT or less, at an excitation voltage of 10 V, demonstrating their utility as a magnetic compass. The power consumed to actuate the resonator is on the order of 20 nW. A theoretical model of the magnetic field sensor was developed using vibration analysis and nonlinear deflection theory. Good agreement was observed between the predicted and observed behavior of the compass.
Can Tetraneutron be a Narrow Resonance?
NASA Astrophysics Data System (ADS)
Fossez, K.; Rotureau, J.; Michel, N.; Płoszajczak, M.
2017-07-01
The search for a resonant four-neutron system has been revived thanks to the recent experimental hints reported in [1]. The existence of such a system would deeply impact our understanding of nuclear matter and requires a critical investigation. In this work, we study the existence of a four-neutron resonance in the quasistationary formalism using ab initio techniques with various two-body chiral interactions. We employ no-core Gamow shell model and density matrix renormalization group method, both supplemented by the use of natural orbitals and a new identification technique for broad resonances. We demonstrate that while the energy of the four-neutron system may be compatible with the experimental value, its width must be larger than the reported upper limit, supporting the interpretation of the experimental observation as a reaction process too short to form a nucleus.
Euclidean resonance in a magnetic field
Ivlev, B.
2007-08-15
An analogy is found between Wigner resonant tunneling and tunneling across a static potential barrier in a static magnetic field. Whereas in the process of Wigner tunneling an electron encounters a classically allowed region where a discrete energy level coincides with its energy, in the magnetic field the potential barrier is constant in the direction of tunneling. Along the tunneling path, certain regions are formed where, in the classical language, the kinetic energy of the motion perpendicular to tunneling is negative. These regions play the role of potential wells, where a discrete energy level can coincide with the electron energy. This phenomenon, which occurs at a certain magnetic field, is called Euclidean resonance and substantially depends on the shape of the potential forces in the direction perpendicular to tunneling. Under conditions of Euclidean resonance, a long-distance underbarrier motion is possible, which can be observed in experiments.
Resonant optical device with a microheater
Lentine, Anthony L.; DeRose, Christopher
2017-04-04
A resonant photonic device is provided. The device comprises an optical waveguiding element, such as an optical resonator, that includes a diode junction region, two signal terminals configured to apply a bias voltage across the junction region, and a heater laterally separated from the optical waveguiding element. A semiconductor electrical barrier element is juxtaposed to the heater. A metallic strip is electrically and thermally connected at one end to a signal terminal of the optical waveguiding element and thermally connected at another end to the barrier element.
Random search for a dark resonance
NASA Astrophysics Data System (ADS)
Kiilerich, Alexander Holm; Mølmer, Klaus
2017-02-01
A pair of resonant laser fields can drive a three-level system into a dark state where it ceases to absorb and emit radiation due to destructive interference. We propose a scheme to search for this resonance by randomly changing the frequency of one of the fields each time a fluorescence photon is detected. The longer the system is probed, the more likely the frequency is close to resonance and the system populates the dark state. Due to the correspondingly long waiting times between detection events, the evolution is nonergodic and the precision of the frequency estimate does not follow from the conventional Cramér-Rao bound of parameter estimation. Instead, a Lévy statistical analysis yields the scaling of the estimation error with time for precision probing of this kind.
A sound absorbing metasurface with coupled resonators
NASA Astrophysics Data System (ADS)
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.
Efimov states near a Feshbach resonance
NASA Astrophysics Data System (ADS)
Massignan, P.; Stoof, H. T. C.
2008-09-01
We describe three-body collisions close to a Feshbach resonance by taking into account two-body scattering processes involving both the open and the closed channels. We extract the atom-dimer scattering length and the three-body recombination rate, predicting the existence at negative scattering length of a sharp minimum in the recombination losses due to the presence of a shallow bound level. We obtain very good agreement with the experimental results in atomic Cs133 of Kraemer [Nature (London) 440, 315 (2006)], and predict the position of Efimov resonances in a gas of K39 atoms.
Conjecture: A Possible nnΛ Resonance
NASA Astrophysics Data System (ADS)
Gibson, B. F.; Afnan, I. R.
2016-03-01
We address the question of whether there might exist a resonance in the nnΛ system, using a rank one separable potential formulation of the Hamiltonian. We explore the eigenvalues of the kernel of the Faddeev equation in the complex energy plane using contour rotation to allow us to analytically continue the kernel onto the second energy sheet. We follow the largest eigenvalue as the nΛ potentials are scaled and the nnΛ continuum is turned into a resonance and then into a bound state of the system.
A resonance approach to cochlear mechanics.
Bell, Andrew
2012-01-01
How does the cochlea analyse sound into its component frequencies? In the 1850s Helmholtz thought it occurred by resonance, whereas a century later Békésy's work indicated a travelling wave. The latter answer seemed to settle the question, but with the discovery in 1978 that the cochlea emits sound, the mechanics of the cochlea was back on the drawing board. Recent studies have raised questions about whether the travelling wave, as currently understood, is adequate to explain observations. Applying basic resonance principles, this paper revisits the question. A graded bank of harmonic oscillators with cochlear-like frequencies and quality factors is simultaneously excited, and it is found that resonance gives rise to similar frequency responses, group delays, and travelling wave velocities as observed by experiment. The overall effect of the group delay gradient is to produce a decelerating wave of peak displacement moving from base to apex at characteristic travelling wave speeds. The extensive literature on chains of coupled oscillators is considered, and the occurrence of travelling waves, pseudowaves, phase plateaus, and forced resonance in such systems is noted. This alternative approach to cochlear mechanics shows that a travelling wave can simply arise as an apparently moving amplitude peak which passes along a bank of resonators without carrying energy. This highlights the possible role of the fast pressure wave and indicates how phase delays and group delays of a set of driven harmonic oscillators can generate an apparent travelling wave. It is possible to view the cochlea as a chain of globally forced coupled oscillators, and this model incorporates fundamental aspects of both the resonance and travelling wave theories.
A Resonance Approach to Cochlear Mechanics
Bell, Andrew
2012-01-01
Background How does the cochlea analyse sound into its component frequencies? In the 1850s Helmholtz thought it occurred by resonance, whereas a century later Békésy's work indicated a travelling wave. The latter answer seemed to settle the question, but with the discovery in 1978 that the cochlea emits sound, the mechanics of the cochlea was back on the drawing board. Recent studies have raised questions about whether the travelling wave, as currently understood, is adequate to explain observations. Approach Applying basic resonance principles, this paper revisits the question. A graded bank of harmonic oscillators with cochlear-like frequencies and quality factors is simultaneously excited, and it is found that resonance gives rise to similar frequency responses, group delays, and travelling wave velocities as observed by experiment. The overall effect of the group delay gradient is to produce a decelerating wave of peak displacement moving from base to apex at characteristic travelling wave speeds. The extensive literature on chains of coupled oscillators is considered, and the occurrence of travelling waves, pseudowaves, phase plateaus, and forced resonance in such systems is noted. Conclusion and significance This alternative approach to cochlear mechanics shows that a travelling wave can simply arise as an apparently moving amplitude peak which passes along a bank of resonators without carrying energy. This highlights the possible role of the fast pressure wave and indicates how phase delays and group delays of a set of driven harmonic oscillators can generate an apparent travelling wave. It is possible to view the cochlea as a chain of globally forced coupled oscillators, and this model incorporates fundamental aspects of both the resonance and travelling wave theories. PMID:23144835
Method of making a piezoelectric shear wave resonator
Wang, Jin S.; Lakin, Kenneth M.; Landin, Allen R.
1987-02-03
An acoustic shear wave resonator comprising a piezoelectric film having its C-axis substantially inclined from the film normal such that the shear wave coupling coefficient significantly exceeds the longitudinal wave coupling coefficient, whereby the film is capable of shear wave resonance, and means for exciting said film to resonate. The film is prepared by deposition in a dc planar magnetron sputtering system to which a supplemental electric field is applied. The resonator structure may also include a semiconductor material having a positive temperature coefficient of resonance such that the resonator has a temperature coefficient of resonance approaching 0 ppm/.degree.C.
A seismic metamaterial: The resonant metawedge
Colombi, Andrea; Colquitt, Daniel; Roux, Philippe; Guenneau, Sebastien; Craster, Richard V.
2016-01-01
Critical concepts from three different fields, elasticity, plasmonics and metamaterials, are brought together to design a metasurface at the geophysical scale, the resonant metawedge, to control seismic Rayleigh waves. Made of spatially graded vertical subwavelength resonators on an elastic substrate, the metawedge can either mode convert incident surface Rayleigh waves into bulk elastic shear waves or reflect the Rayleigh waves creating a “seismic rainbow” effect analogous to the optical rainbow for electromagnetic metasurfaces. Time-domain spectral element simulations demonstrate the broadband efficacy of the metawedge in mode conversion while an analytical model is developed to accurately describe and predict the seismic rainbow effect; allowing the metawedge to be designed without the need for extensive parametric studies and simulations. The efficiency of the resonant metawedge shows that large-scale mechanical metamaterials are feasible, will have application, and that the time is ripe for considering many optical devices in the seismic and geophysical context. PMID:27283587
A seismic metamaterial: The resonant metawedge.
Colombi, Andrea; Colquitt, Daniel; Roux, Philippe; Guenneau, Sebastien; Craster, Richard V
2016-06-10
Critical concepts from three different fields, elasticity, plasmonics and metamaterials, are brought together to design a metasurface at the geophysical scale, the resonant metawedge, to control seismic Rayleigh waves. Made of spatially graded vertical subwavelength resonators on an elastic substrate, the metawedge can either mode convert incident surface Rayleigh waves into bulk elastic shear waves or reflect the Rayleigh waves creating a "seismic rainbow" effect analogous to the optical rainbow for electromagnetic metasurfaces. Time-domain spectral element simulations demonstrate the broadband efficacy of the metawedge in mode conversion while an analytical model is developed to accurately describe and predict the seismic rainbow effect; allowing the metawedge to be designed without the need for extensive parametric studies and simulations. The efficiency of the resonant metawedge shows that large-scale mechanical metamaterials are feasible, will have application, and that the time is ripe for considering many optical devices in the seismic and geophysical context.
A seismic metamaterial: The resonant metawedge
NASA Astrophysics Data System (ADS)
Colombi, Andrea; Colquitt, Daniel; Roux, Philippe; Guenneau, Sebastien; Craster, Richard V.
2016-06-01
Critical concepts from three different fields, elasticity, plasmonics and metamaterials, are brought together to design a metasurface at the geophysical scale, the resonant metawedge, to control seismic Rayleigh waves. Made of spatially graded vertical subwavelength resonators on an elastic substrate, the metawedge can either mode convert incident surface Rayleigh waves into bulk elastic shear waves or reflect the Rayleigh waves creating a “seismic rainbow” effect analogous to the optical rainbow for electromagnetic metasurfaces. Time-domain spectral element simulations demonstrate the broadband efficacy of the metawedge in mode conversion while an analytical model is developed to accurately describe and predict the seismic rainbow effect; allowing the metawedge to be designed without the need for extensive parametric studies and simulations. The efficiency of the resonant metawedge shows that large-scale mechanical metamaterials are feasible, will have application, and that the time is ripe for considering many optical devices in the seismic and geophysical context.
A Resonant Damping Study Using Piezoelectric Materials
NASA Technical Reports Server (NTRS)
Min, J. B.; Duffy, K. P.; Choi, B. B.; Morrison, C. R.; Jansen, R. H.; Provenza, A. J.
2008-01-01
Excessive vibration of turbomachinery blades causes high cycle fatigue (HCF) problems requiring damping treatments to mitigate vibration levels. Based on the technical challenges and requirements learned from previous turbomachinery blade research, a feasibility study of resonant damping control using shunted piezoelectric patches with passive and active control techniques has been conducted on cantilever beam specimens. Test results for the passive damping circuit show that the optimum resistive shunt circuit reduces the third bending resonant vibration by almost 50%, and the optimum inductive circuit reduces the vibration by 90%. In a separate test, active control reduced vibration by approximately 98%.
A Mechanical Resonance Apparatus for Undergraduate Laboratories.
ERIC Educational Resources Information Center
Jones, Christopher C.
1995-01-01
Reports the use of a heavy duty hacksaw blade and a 1000 turn pick-up coil to form the basis of a mechanical oscillator for a laboratory exercise in mechanical resonance designed for either the elementary undergraduate course or in association with an upper level mechanics course. (LZ)
A Mechanical Resonance Apparatus for Undergraduate Laboratories.
ERIC Educational Resources Information Center
Jones, Christopher C.
1995-01-01
Reports the use of a heavy duty hacksaw blade and a 1000 turn pick-up coil to form the basis of a mechanical oscillator for a laboratory exercise in mechanical resonance designed for either the elementary undergraduate course or in association with an upper level mechanics course. (LZ)
A warning on fission resonance intergrals: Caveat utor
Holden, N.E.
1988-01-01
A common error is made in defining the resonance integral in most tabulations and handbooks. Although it has a minor effect on the capture resonance integral and on the fission resonance integral for the fissile nuclides, it leads to gross errors in the fission resonance integral for the fertile nuclides. The errors in the fission resonance integral for fertile nuclides of the elements from thorium through curium in the ENDF/B-V library will be presented. Let the user beware.
An actively controlled silicon ring resonator with a fully tunable Fano resonance
NASA Astrophysics Data System (ADS)
Li, A.; Bogaerts, W.
2017-09-01
We demonstrate a novel way to generate Fano resonance with tunable wavelength, extinction ratio, and slope rate. The device is a silicon add-drop microring with two integrated tunable reflectors inside, which form an embedded Fabry-Perot cavity. The fabrication is executed at a commercial CMOS foundry. Fano resonance at the drop port is generated from the interference between the Fabry-Perot cavity mode and the ring resonance mode. By tuning the reflectivities of these two reflectors with integrated heaters, various Fano resonance shapes can be achieved with a maximum extinction ratio over 40 dB and a slope rate more than 700 dB/nm.
A birdcage resonator for intracavitary MR imaging.
Merchant, T E; Ballon, D; Koutcher, J A; Miodownik, S; Schwartz, L; Minsky, B D
1993-01-01
An intracavitary probe for magnetic resonance imaging of the pelvis has been developed that takes advantage of the "inside-out" spatial characteristics of a birdcage resonator. The probe consists of an eight-leg, birdcage resonator in a low-pass configuration operating in receive-only mode. The resonator circuit is mounted on a solid rod, is encased in Teflon, and has been used to obtain detailed images of pelvic anatomy in a male canine. The approximate cylindrical symmetry of the external sensitivity profile of this type of circuit, employed in an intracavitary application, demonstrates the potential superiority of this type of probe design over single-loop intracavitary coils. Axial, coronal, and sagittal MR images, obtained with 8 and 16 cm fields of view, are presented to illustrate the advantages of this type of intracavitary probe compared with conventional body-coil images. The prototype described in this report has been designed for clinical use in human subjects and is currently undergoing testing to determine its efficacy in the evaluation of rectal, prostate, and gynecologic pathology.
Folded cavity design for a ruby resonator
NASA Technical Reports Server (NTRS)
Arunkumar, K. A.; Trolinger, James D.
1988-01-01
A folded cavity laser resonator operating in the TEM(00) mode has been built and tested. The new oscillator configuration leads to an increase in efficiency and to better line narrowing due to the increased number of passes through the laser rod and tuning elements, respectively. The modification is shown to lead to cavity ruggedization.
Resonance fluorescence of a cold atom in a high-finesse resonator
Bienert, Marc; Torres, J. Mauricio; Zippilli, Stefano; Morigi, Giovanna
2007-07-15
We study the spectra of emission of a system composed by an atom, tightly confined inside a high-finesse resonator, when the atom is driven by a laser and is at steady state of the cooling dynamics induced by laser and cavity fields. In general, the spectrum of resonance fluorescence and the spectrum at the cavity output contain complementary information about the dynamics undergone by the system. In certain parameter regimes, quantum interference effects between the scattering processes induced by cavity and laser fields lead to the selective suppression of features of the resonance fluorescence spectrum, which are otherwise visible in the spectrum of laser-cooled atoms in free space.
Experimental study of resonance fiber optic gyroscope employing a dual-ring resonator
NASA Astrophysics Data System (ADS)
Fan, Yue; Wang, Wei
2016-09-01
A dual-ring resonator which is available to alter the full width at half maximum (FWHM) without altering the free spectrum range (FSR) for practice applications is analyzed theoretically and set up in practice. The parameters of the dual-ring resonator have been optimized in simulation, the resonance depth and the dynamic range are enhanced. The prototype is set up with single mode fiber of 8 meter and two 95 : 5 couplers for open loop experiment. The FWHM of the dual-ring resonator is demonstrated less than 1.5MHz and the fineness is calculated to be 37 during the frequency sweeping experiment. The frequency locking experiment with demodulation curve method has been accomplished, and the locking time achieves less than 40ms. All these provide a basic reference for optimizing the resonance fiber optic gyro based on dual-ring resonator.
Isolated resonator gyroscope with a drive and sense plate
NASA Technical Reports Server (NTRS)
Challoner, A. Dorian (Inventor); Shcheglov, Kirill V. (Inventor)
2006-01-01
The present invention discloses a resonator gyroscope comprising a vibrationally isolated resonator including a proof mass, a counterbalancing plate having an extensive planar region, and one or more flexures interconnecting the proof mass and counterbalancing plate. A baseplate is affixed to the resonator by the one or more flexures and sense and drive electrodes are affixed to the baseplate proximate to the extensive planar region of the counterbalancing plate for exciting the resonator and sensing movement of the gyroscope. The isolated resonator transfers substantially no net momentum to the baseplate when the resonator is excited.
Isolated resonator gyroscope with a drive and sense plate
NASA Technical Reports Server (NTRS)
Challoner, A. Dorian (Inventor); Shcheglov, Kirill V. (Inventor)
2006-01-01
The present invention discloses a resonator gyroscope comprising a vibrationally isolated resonator including a proof mass, a counterbalancing plate having an extensive planar region, and one or more flexures interconnecting the proof mass and counterbalancing plate. A baseplate is affixed to the resonator by the one or more flexures and sense and drive electrodes are affixed to the baseplate proximate to the extensive planar region of the counterbalancing plate for exciting the resonator and sensing movement of the gyroscope. The isolated resonator transfers substantially no net momentum to the baseplate when the resonator is excited.
A curved resonant flexoelectric actuator
NASA Astrophysics Data System (ADS)
Zhang, Shuwen; Liu, Kaiyuan; Xu, Minglong; Shen, Shengping
2017-08-01
Flexoelectricity is an electro-mechanical coupling effect that exists in all dielectrics and has the potential to replace piezoelectric actuating on the microscale. In this letter, a curved flexoelectric actuator with non-polarized polyvinylidene fluoride is presented and shown to exhibit good electro-mechanical properties. This provides experimental support for a body of theoretical research into converse flexoelectricity in polymeric materials. In addition, this work demonstrates the feasibility of lead-free microscale actuating without piezoelectricity.
Optical Resonant Cavity in a Nanotaper
Lee, Sang Hyun; Goto, Takenari; Miyazaki, Hiroshi; Chang, Jiho; Yao, Takafumi
2010-01-01
The present study describes an optical resonant cavity in a nanotaper with scale reduction from micro to several nanometers. Both experimental results and a finite-difference time-domain (FDTD)-based simulation suggested that the nanometer-scale taper with a diameter similar to the wavelength of light acted as a mirror, which facilitated the formation of a laser cavity and caused lasing in ZnO nanotapers. As the light inside the nanotaper propagated toward the apex, the lateral mode was reduced and reflection occurred. This report suggests that use of the resonant optical cavities in nanotapers might result in novel active and passive optical components, which will broaden the horizons of photonic technology.
Unstable resonators with a distributed focusing gain.
Ferguson, T R
1994-08-20
The geometrical optics approximation is used to form a model of axisymmetric unstable resonators having distributed focus, gain, and loss. A tapered reflectivity feedback mirror is included. The rate equations for propagation through the focusing gain medium are derived. A unique grid is found for propagation without interpolation along eigenrays in each direction. Numerical examples show the effects of distributed gain and focus on the axial and transverse intensity distributions.
Radiative losses of a birdcage resonator.
Harpen, M D
1993-05-01
We present a derivation of the losses in a birdcage resonator due to radiation. We also present an expression for the radiation limited Q. It is shown that in head coil imaging at 63 MHz radiative losses may account for 20% of the total loss with a radiation limited Q on the order of 150. The results are shown to be consistent with those reported in the recent literature.
Electrical tuning of a quantum plasmonic resonance
Liu, Xiaoge; Kang, Ju -Hyung; Yuan, Hongtao; ...
2017-06-12
Surface plasmon (SP) excitations in metals facilitate confinement of light into deep-subwavelength volumes and can induce strong light–matter interaction. Generally, the SP resonances supported by noble metal nanostructures are explained well by classical models, at least until the nanostructure size is decreased to a few nanometres, approaching the Fermi wavelength λF of the electrons. Although there is a long history of reports on quantum size effects in the plasmonic response of nanometre-sized metal particles systematic experimental studies have been hindered by inhomogeneous broadening in ensemble measurements, as well as imperfect control over size, shape, faceting, surface reconstructions, contamination, charging effectsmore » and surface roughness in single-particle measurements. In particular, observation of the quantum size effect in metallic films and its tuning with thickness has been challenging as they only confine carriers in one direction. Here, we show active tuning of quantum size effects in SP resonances supported by a 20-nm-thick metallic film of indium tin oxide (ITO), a plasmonic material serving as a low-carrier-density Drude metal. An ionic liquid (IL) is used to electrically gate and partially deplete the ITO layer. The experiment shows a controllable and reversible blue-shift in the SP resonance above a critical voltage. As a result, a quantum-mechanical model including the quantum size effect reproduces the experimental results, whereas a classical model only predicts a red shift.« less
Electrical tuning of a quantum plasmonic resonance
NASA Astrophysics Data System (ADS)
Liu, Xiaoge; Kang, Ju-Hyung; Yuan, Hongtao; Park, Junghyun; Kim, Soo Jin; Cui, Yi; Hwang, Harold Y.; Brongersma, Mark L.
2017-09-01
Surface plasmon (SP) excitations in metals facilitate confinement of light into deep-subwavelength volumes and can induce strong light-matter interaction. Generally, the SP resonances supported by noble metal nanostructures are explained well by classical models, at least until the nanostructure size is decreased to a few nanometres, approaching the Fermi wavelength λF of the electrons. Although there is a long history of reports on quantum size effects in the plasmonic response of nanometre-sized metal particles, systematic experimental studies have been hindered by inhomogeneous broadening in ensemble measurements, as well as imperfect control over size, shape, faceting, surface reconstructions, contamination, charging effects and surface roughness in single-particle measurements. In particular, observation of the quantum size effect in metallic films and its tuning with thickness has been challenging as they only confine carriers in one direction. Here, we show active tuning of quantum size effects in SP resonances supported by a 20-nm-thick metallic film of indium tin oxide (ITO), a plasmonic material serving as a low-carrier-density Drude metal. An ionic liquid (IL) is used to electrically gate and partially deplete the ITO layer. The experiment shows a controllable and reversible blue-shift in the SP resonance above a critical voltage. A quantum-mechanical model including the quantum size effect reproduces the experimental results, whereas a classical model only predicts a red shift.
Fano resonance in a subwavelength Mie-based metamolecule with split ring resonator
NASA Astrophysics Data System (ADS)
Wang, Xiaobo; Zhou, Ji
2017-06-01
In this letter, we report a method of symmetry-breaking in an artificial Mie-based metamolecule. A Fano resonance with a Q factor of 96 is observed at microwave frequencies in a structure combining a split ring resonator and a high-permittivity dielectric cube. Calculations indicate that resonant frequency tunability will result from the alteration of the cube's permittivity. The asymmetric spectrum is attributed to both constructive and destructive near-field interactions between the two distinct resonators. Experimental data and simulation results are in good agreement. The underlying physics is seen in field distribution and dipole analysis. This work substantiates an approach for the manipulation of Mie resonances which can potentially be utilized in light modulating and sensing.
Is a Trineutron Resonance Lower in Energy than a Tetraneutron Resonance?
Gandolfi, Stefano; Hammer, Hans -Werner; Klos, P.; ...
2017-06-08
Here, we present quantum Monte Carlo calculations of few-neutron systems confined in external potentials based on local chiral interactions at next-to-next-to-leading order in chiral effective field theory. The energy and radial densities for these systems are calculated in different external Woods-Saxon potentials. We assume that their extrapolation to zero external-potential depth provides a quantitative estimate of three- and four-neutron resonances. The validity of this assumption is demonstrated by benchmarking with an exact diagonalization in the two-body case. We find that the extrapolated trineutron resonance, as well as the energy for shallow well depths, is lower than the tetraneutron resonance energy.more » This suggests that a three-neutron resonance exists below a four-neutron resonance in nature and is potentially measurable. To confirm that the relative ordering of three- and four-neutron resonances is not an artifact of the external confinement, we test that the odd-even staggering in the helium isotopic chain is reproduced within this approach. Finally, we discuss similarities between our results and ultracold Fermi gases.« less
Is a Trineutron Resonance Lower in Energy than a Tetraneutron Resonance?
NASA Astrophysics Data System (ADS)
Gandolfi, S.; Hammer, H.-W.; Klos, P.; Lynn, J. E.; Schwenk, A.
2017-06-01
We present quantum Monte Carlo calculations of few-neutron systems confined in external potentials based on local chiral interactions at next-to-next-to-leading order in chiral effective field theory. The energy and radial densities for these systems are calculated in different external Woods-Saxon potentials. We assume that their extrapolation to zero external-potential depth provides a quantitative estimate of three- and four-neutron resonances. The validity of this assumption is demonstrated by benchmarking with an exact diagonalization in the two-body case. We find that the extrapolated trineutron resonance, as well as the energy for shallow well depths, is lower than the tetraneutron resonance energy. This suggests that a three-neutron resonance exists below a four-neutron resonance in nature and is potentially measurable. To confirm that the relative ordering of three- and four-neutron resonances is not an artifact of the external confinement, we test that the odd-even staggering in the helium isotopic chain is reproduced within this approach. Finally, we discuss similarities between our results and ultracold Fermi gases.
Birth of a resonant attosecond wavepacket
NASA Astrophysics Data System (ADS)
Argenti, L.; Gruson, V.; Barreau, L.; Jimenez-Galan, A.; Risoud, F.; Caillat, J.; Maquet, A.; Carre, B.; Lepetit, F.; Hergott, J.-F.; Ruchon, T.; Taieb, R.; Martin, F.; Salieres, P.
2016-05-01
Both amplitude and phase are needed to characterize the dynamics of a wavepacket. However, such characterization is difficult when both attosecond and femtosecond timescales are involved, as it is the case for broadband photoionization to a continuum encompassing autoionizing states. Here we demonstrate that Rainbow RABBIT, a new attosecond interferometry, allows the measurement of amplitude and phase of a photoelectron wavepacket created through a Fano resonance with unprecedented precision. In the experiment, a tunable attosecond pulse train is combined with the fundamental laser pulse to induce two-photon transitions in helium via an intermediate autoionizing state. From the energy and time-delay resolved signal, we fully reconstruct the resonant electron wavepacket as it builds up in the continuum. Measurements accurately match the predictions of a new time-resolved multi-photon resonant model, known to reproduce ab initio calculations. This agreement confirms the potential of Rainbow RABBIT to investigate photoemission delays in ultrafast processes governed by electron correlation, as well as to control structured electron wavepackets. now at Univ. Central Florida, Orlando, FL (USA).
A MEMS square Chladni plate resonator
NASA Astrophysics Data System (ADS)
Pala, Sedat; Azgın, Kıvanç
2016-10-01
This paper presents the design, fabrication and tests of a micro-fabricated MEMS ‘Chladni’ plate resonator. The proposed MEMS resonator has a square plate geometry having a side length of 1400 µm and a height of 35 µm. Its geometry and electrode layout are designed to analyze and test as many modes as possible. The MEMS plate is fabricated using a silicon-on-insulator process with a 35 µm thick < \\text{1} \\text{1} \\text{1}> silicon layer on a glass substrate. Transverse vibration of the plate is investigated to obtain closed form natural frequencies and mode shapes, which are derived using the Rayleigh-Ritz energy method, with an electrostatic softening effect included. Closed form equations for the calculation of effective stiffness’, masses and natural frequencies of the two modes (mode (1,1) and mode (2,0)-(0,2)) are presented, with and without electrostatic softening. The analytical model is verified for those modes by finite-element simulations, frequency response tests in vacuum and laser Doppler vibrometer (LDV) experiments. The derived model deviates from the finite-element analysis by 3.35% for mode (1,1) and 6.15% for mode (2,0)-(0,2). For verification, the frequency responses of the plates are measured with both electrostatic excitation-detection at around 20 mTorr vacuum ambient and LDV at around 0.364 mTorr vacuum ambient. The resonance frequency and Q-factor of mode (1,1) are measured to be 104.2 kHz and 14 300, respectively. For mode (2,0)-(0,2), the measured resonance frequency and Q-factor are 156.68 kHz and 10 700, respectively. The presented LDV results also support both natural frequencies of interest and corresponding mode shapes of the plate structure.
2000-06-23
presented. Resonance - tunneling structures with one and two quantum wells (QW) were fabricated in the same MBE technique conditions. The structures were...thickness was used as barriers of resonance - tunneling structures. GaAs is a quantum well material. In case of DBRTS the width of QW has made 4 nm, and in
NASA Astrophysics Data System (ADS)
Asoubar, Daniel; Wyrowski, Frank; Schweitzer, Hagen; Hellmann, Christian; Kuhn, Michael
2014-05-01
Nowadays lasers cover a broad spectrum of applications, like laser material processing, metrology and communications. Therefore a broad variety of different lasers, containing various active media and resonator setups, are used to provide high design flexibility. The optimization of such multi-parameter laser setups requires powerful simulation techniques. In literature mainly three practical resonator modeling techniques can be found: Rigorous techniques, e.g. the finite element method (FEM), approximated solutions based on paraxial Gaussian beam tracing by ABCD matrices and the Fox and Li algorithm are used to analyze transversal resonator modes. All of these existing approaches have in common, that only a single simulation technique is used for the whole resonator. In contrast we reformulate the scalar Fox and Li integral equation for resonator eigenmode calculation into a fully vectorial field tracing operator equation. This allows the flexible combination of different modeling techniques in different subdomains of the resonator. The work introduces the basic concepts of field tracing in resonators to calculate vectorial, transversal eigenmodes of stable and unstable resonators.
Resonant tunnelling in a quantum oxide superlattice
Choi, Woo Seok; Lee, Sang A.; You, Jeong Ho; Lee, Suyoun; Lee, Ho Nyung
2015-06-24
Resonant tunneling is a quantum mechanical process that has long been attracting both scientific and technological attention owing to its intriguing underlying physics and unique applications for high-speed electronics. The materials system exhibiting resonant tunneling, however, has been largely limited to the conventional semiconductors, partially due to their excellent crystalline quality. Here we show that a deliberately designed transition metal oxide superlattice exhibits a resonant tunneling behaviour with a clear negative differential resistance. The tunneling occurred through an atomically thin, lanthanum δ- doped SrTiO_{3} layer, and the negative differential resistance was realized on top of the bi-polar resistance switching typically observed for perovskite oxide junctions. This combined process resulted in an extremely large resistance ratio (~10^{5}) between the high and low resistance states. Lastly, the unprecedentedly large control found in atomically thin δ-doped oxide superlattices can open a door to novel oxide-based high-frequency logic devices.
Resonant tunnelling in a quantum oxide superlattice
Choi, Woo Seok; Lee, Sang A.; You, Jeong Ho; ...
2015-06-24
Resonant tunneling is a quantum mechanical process that has long been attracting both scientific and technological attention owing to its intriguing underlying physics and unique applications for high-speed electronics. The materials system exhibiting resonant tunneling, however, has been largely limited to the conventional semiconductors, partially due to their excellent crystalline quality. Here we show that a deliberately designed transition metal oxide superlattice exhibits a resonant tunneling behaviour with a clear negative differential resistance. The tunneling occurred through an atomically thin, lanthanum δ- doped SrTiO3 layer, and the negative differential resistance was realized on top of the bi-polar resistance switching typicallymore » observed for perovskite oxide junctions. This combined process resulted in an extremely large resistance ratio (~105) between the high and low resistance states. Lastly, the unprecedentedly large control found in atomically thin δ-doped oxide superlattices can open a door to novel oxide-based high-frequency logic devices.« less
A review of droplet resonators: Operation method and application
NASA Astrophysics Data System (ADS)
Wang, Yan; Li, Hanyang; Zhao, Liyuan; Wu, Bing; Liu, Shuangqiang; Liu, Yongjun; Yang, Jun
2016-12-01
Droplet resonators hold promise as a special class of optical cavities for numerous applications in micro-optical. Owing to liquid surface tension, droplet resonators possess nearly perfect spherical geometry and exceptionally smooth surfaces that prompt more and more meritorious applications to be exploit. Herein, we survey two typical operation methods of the droplet resonators, passive and active droplet resonator. Besides, droplet applications as high-performance lasers and sensors have been discussed. Although these applications have brought us tremendous value, the research for droplet resonators are still in its infancy, added potential application and intrinsic investigation of the droplet resonators should be developed in the future work.
Optomechanical response of a nonlinear mechanical resonator
NASA Astrophysics Data System (ADS)
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.
A Technique for Adjusting Eigenfrequencies of WGM Resonators
NASA Technical Reports Server (NTRS)
Strekalov, Dmitry; Savchenkov, Anatoliy; Maleki, Lute; Matsko, Andrey; Iltchenko, Vladimir; Martin, Jan
2009-01-01
A simple technique has been devised for making small, permanent changes in the eigenfrequencies (resonance frequencies) of whispering-gallery-mode (WGM) dielectric optical resonators that have high values of the resonance quality factor (Q). The essence of the technique is to coat the resonator with a thin layer of a transparent polymer having an index of refraction close to that of the resonator material. Successive small frequency adjustments can be made by applying successive coats. The technique was demonstrated on a calcium fluoride resonator to which successive coats of a polymer were applied by use of a hand-made wooden brush. To prevent temperature- related frequency shifts that could interfere with the verification of the effectiveness of this technique, the temperature of the resonator was stabilized by means of a three-stage thermoelectric cooler. Measurements of the resonator spectrum showed the frequency shifts caused by the successive coating layers.
Jauregui, Rigoberto; Asua, Estibaliz; Portilla, Joaquin; Etxebarria, Victor
2015-03-01
This paper presents a reliable and integrated technique for determining the resonant frequency of radio frequency resonators, which can be of interest for different purposes. The approach uses a heterodyne scheme as phase detector coupled to a voltage-controlled oscillator. The system seeks the oscillator frequency that produces a phase null in the resonator, which corresponds to the resonant frequency. A complete explanation of the technique to determine the resonant frequency is presented and experimentally tested. The method has been applied to a high-precision displacement sensor based on resonant cavity, obtaining a theoretical nanometric precision.
A general theory for bandgap estimation in locally resonant metastructures
NASA Astrophysics Data System (ADS)
Sugino, C.; Xia, Y.; Leadenham, S.; Ruzzene, M.; Erturk, A.
2017-10-01
Locally resonant metamaterials are characterized by bandgaps at wavelengths that are much larger than the lattice size, enabling low-frequency vibration attenuation. Typically, bandgap analyses and predictions rely on the assumption of traveling waves in an infinite medium, and do not take advantage of modal representations typically used for the analysis of the dynamic behavior of finite structures. Recently, we developed a method for understanding the locally resonant bandgap in uniform finite metamaterial beams using modal analysis. Here we extend that framework to general locally resonant 1D and 2D metastructures (i.e. locally resonant metamaterial-based finite structures) with specified boundary conditions using a general operator formulation. Using this approach, along with the assumption of an infinite number of resonators tuned to the same frequency, the frequency range of the locally resonant bandgap is easily derived in closed form. Furthermore, the bandgap expression is shown to be the same regardless of the type of vibration problem under consideration, depending only on the added mass ratio and target frequency. For practical designs with a finite number of resonators, it is shown that the number of resonators required for the bandgap to appear increases with increased target frequency, i.e. more resonators are required for higher vibration modes. Additionally, it is observed that there is an optimal, finite number of resonators which gives a bandgap that is wider than the infinite-resonator bandgap, and that the optimal number of resonators increases with target frequency and added mass ratio. As the number of resonators becomes sufficiently large, the bandgap converges to the derived infinite-resonator bandgap. Furthermore, the derived bandgap edge frequencies are shown to agree with results from dispersion analysis using the plane wave expansion method. The model is validated experimentally for a locally resonant cantilever beam under base
NASA Astrophysics Data System (ADS)
Ly, Aliou; Szymanski, Benjamin; Bretenaker, Fabien
2015-08-01
We present an experimental technique allowing to stabilize the frequency of the non-resonant wave in a singly resonant optical parametric oscillator (SRO) down to the kHz level, much below the pump frequency noise level. By comparing the frequency of the non-resonant wave with a reference cavity, the pump frequency noise is imposed to the frequency of the resonant wave and is thus subtracted from the frequency of the non-resonant wave. This permits the non-resonant wave obtained from such a SRO to be simultaneously powerful and frequency stable, which is usually impossible to obtain when the resonant wave frequency is stabilized.
Soft resonator of omnidirectional resonance for acoustic metamaterials with a negative bulk modulus.
Jing, Xiaodong; Meng, Yang; Sun, Xiaofeng
2015-11-05
Monopolar resonance is of fundamental importance in the acoustic field. Here, we present the realization of a monopolar resonance that goes beyond the concept of Helmholtz resonators. The balloon-like soft resonator (SR) oscillates omnidirectionally and radiates from all parts of its spherical surface, eliminating the need for a hard wall for the cavity and baffle effects. For airborne sound, such a low-modulus resonator can be made extremely lightweight. Deep subwavelength resonance is achieved when the SR is tuned by adjusting the shell thickness, benefiting from the large density contrast between the shell material and the encapsulated gas. The SR resonates with near-perfect monopole symmetry, as demonstrated by the theoretical and experimental results, which are in excellent agreement. For a lattice of SRs, a band gap occurs and blocks near-total transmission, and the effective bulk modulus exhibits a prominent negative band, while the effective mass density remains unchanged. Our study shows that the SR is suitable for building 3D acoustic metamaterials and provides a basis for constructing left-handed materials as a new means of creating a negative bulk modulus.
Soft resonator of omnidirectional resonance for acoustic metamaterials with a negative bulk modulus
NASA Astrophysics Data System (ADS)
Jing, Xiaodong; Meng, Yang; Sun, Xiaofeng
2015-11-01
Monopolar resonance is of fundamental importance in the acoustic field. Here, we present the realization of a monopolar resonance that goes beyond the concept of Helmholtz resonators. The balloon-like soft resonator (SR) oscillates omnidirectionally and radiates from all parts of its spherical surface, eliminating the need for a hard wall for the cavity and baffle effects. For airborne sound, such a low-modulus resonator can be made extremely lightweight. Deep subwavelength resonance is achieved when the SR is tuned by adjusting the shell thickness, benefiting from the large density contrast between the shell material and the encapsulated gas. The SR resonates with near-perfect monopole symmetry, as demonstrated by the theoretical and experimental results, which are in excellent agreement. For a lattice of SRs, a band gap occurs and blocks near-total transmission, and the effective bulk modulus exhibits a prominent negative band, while the effective mass density remains unchanged. Our study shows that the SR is suitable for building 3D acoustic metamaterials and provides a basis for constructing left-handed materials as a new means of creating a negative bulk modulus.
Soft resonator of omnidirectional resonance for acoustic metamaterials with a negative bulk modulus
Jing, Xiaodong; Meng, Yang; Sun, Xiaofeng
2015-01-01
Monopolar resonance is of fundamental importance in the acoustic field. Here, we present the realization of a monopolar resonance that goes beyond the concept of Helmholtz resonators. The balloon-like soft resonator (SR) oscillates omnidirectionally and radiates from all parts of its spherical surface, eliminating the need for a hard wall for the cavity and baffle effects. For airborne sound, such a low-modulus resonator can be made extremely lightweight. Deep subwavelength resonance is achieved when the SR is tuned by adjusting the shell thickness, benefiting from the large density contrast between the shell material and the encapsulated gas. The SR resonates with near-perfect monopole symmetry, as demonstrated by the theoretical and experimental results, which are in excellent agreement. For a lattice of SRs, a band gap occurs and blocks near-total transmission, and the effective bulk modulus exhibits a prominent negative band, while the effective mass density remains unchanged. Our study shows that the SR is suitable for building 3D acoustic metamaterials and provides a basis for constructing left-handed materials as a new means of creating a negative bulk modulus. PMID:26538085
Internal Resonance in a Vibrating Beam: A Zoo of Nonlinear Resonance Peaks
Mangussi, Franco
2016-01-01
In oscillating mechanical systems, nonlinearity is responsible for the departure from proportionality between the forces that sustain their motion and the resulting vibration amplitude. Such effect may have both beneficial and harmful effects in a broad class of technological applications, ranging from microelectromechanical devices to edifice structures. The dependence of the oscillation frequency on the amplitude, in particular, jeopardizes the use of nonlinear oscillators in the design of time-keeping electronic components. Nonlinearity, however, can itself counteract this adverse response by triggering a resonant interaction between different oscillation modes, which transfers the excess of energy in the main oscillation to higher harmonics, and thus stabilizes its frequency. In this paper, we examine a model for internal resonance in a vibrating elastic beam clamped at its two ends. In this case, nonlinearity occurs in the form of a restoring force proportional to the cube of the oscillation amplitude, which induces resonance between modes whose frequencies are in a ratio close to 1:3. The model is based on a representation of the resonant modes as two Duffing oscillators, coupled through cubic interactions. Our focus is put on illustrating the diversity of behavior that internal resonance brings about in the dynamical response of the system, depending on the detailed form of the coupling forces. The mathematical treatment of the model is developed at several approximation levels. A qualitative comparison of our results with previous experiments and numerical calculations on elastic beams is outlined. PMID:27648829
Internal Resonance in a Vibrating Beam: A Zoo of Nonlinear Resonance Peaks.
Mangussi, Franco; Zanette, Damián H
2016-01-01
In oscillating mechanical systems, nonlinearity is responsible for the departure from proportionality between the forces that sustain their motion and the resulting vibration amplitude. Such effect may have both beneficial and harmful effects in a broad class of technological applications, ranging from microelectromechanical devices to edifice structures. The dependence of the oscillation frequency on the amplitude, in particular, jeopardizes the use of nonlinear oscillators in the design of time-keeping electronic components. Nonlinearity, however, can itself counteract this adverse response by triggering a resonant interaction between different oscillation modes, which transfers the excess of energy in the main oscillation to higher harmonics, and thus stabilizes its frequency. In this paper, we examine a model for internal resonance in a vibrating elastic beam clamped at its two ends. In this case, nonlinearity occurs in the form of a restoring force proportional to the cube of the oscillation amplitude, which induces resonance between modes whose frequencies are in a ratio close to 1:3. The model is based on a representation of the resonant modes as two Duffing oscillators, coupled through cubic interactions. Our focus is put on illustrating the diversity of behavior that internal resonance brings about in the dynamical response of the system, depending on the detailed form of the coupling forces. The mathematical treatment of the model is developed at several approximation levels. A qualitative comparison of our results with previous experiments and numerical calculations on elastic beams is outlined.
Resonant-tunnelling diode oscillator using a slot-coupled quasioptical open resonator
NASA Technical Reports Server (NTRS)
Stephan, K. D.; Brown, E. R.; Parker, C. D.; Goodhue, W. D.; Chen, C. L.
1991-01-01
A resonant-tunneling diode has oscillated at X-band frequencies in a microwave circuit consisting of a slot antenna coupled to a semiconfocal open resonator. Coupling between the open resonator and the slot oscillator improves the noise-to-carrier ratio by about 36 dB relative to that of the slot oscillator alone in the 100-200 kHz range. A circuit operating near 10 GHz has been designed as a scale model for millimeter- and submillimeter-wave applications.
Proximity to Intrinsic Depolarizing Resonances with a Partial Siberian Snake
NASA Astrophysics Data System (ADS)
Crandell, D. A.; Alexeeva, L. V.; Anferov, V. A.; Blinov, B. B.; Chu, C. M.; Caussyn, D. D.; Courant, E. D.; Gladycheva, S. E.; Hu, S.; Krisch, A. D.; Nurushev, T. S.; Phelps, R. A.; Ratner, L. G.; Varzar, S. M.; Wong, V. K.; Derbenev, Ya. S.; Lee, S. Y.; Rinckel, T.; Schwandt, P.; Sperisen, F.; Stephenson, E. J.; von Przewoski, B.; Baiod, R.; Russell, A. D.; Ohmori, C.; Sato, H.
1996-05-01
Partial Siberian snakes are effective in overcoming imperfection depolarizing resonances, but they may also change the crossing energy for intrinsic depolarizing resonances. We experimentally investigated the effect of a partial Siberian snake near intrinsic depolarizing resonances with stored 140 MeV and 160 MeV polarized proton beams. Using various partial Siberian snake strengths up to 30%, depolarization was observed; this may be due to a change in the spin precession frequency which moves the energy of nearby intrinsic depolarizing resonances.
Tunable cavity resonator including a plurality of MEMS beams
Peroulis, Dimitrios; Fruehling, Adam; Small, Joshua Azariah; Liu, Xiaoguang; Irshad, Wasim; Arif, Muhammad Shoaib
2015-10-20
A tunable cavity resonator includes a substrate, a cap structure, and a tuning assembly. The cap structure extends from the substrate, and at least one of the substrate and the cap structure defines a resonator cavity. The tuning assembly is positioned at least partially within the resonator cavity. The tuning assembly includes a plurality of fixed-fixed MEMS beams configured for controllable movement relative to the substrate between an activated position and a deactivated position in order to tune a resonant frequency of the tunable cavity resonator.
Creating a magnetic resonance imaging ontology
Lasbleiz, Jérémy; Saint-Jalmes, Hervé; Duvauferrier, Régis; Burgun, Anita
2011-01-01
The goal of this work is to build an ontology of Magnetic Resonance Imaging. The MRI domain has been analysed regarding MRI simulators and the DICOM standard. Tow MRI simulators have been analysed: JEMRIS, which is developed in XML and C++, has a hierarchical organisation and SIMRI, which is developed in C, has a good representation of MRI physical processes. To build the ontology we have used Protégé 4, owl2 that allows quantitative representations. The ontology has been validated by a reasoner (Fact++) and by a good representation of DICOM headers and of MRI processes. The MRI ontology would improved MRI simulators and eased semantic interoperability. PMID:21893854
Coherence resonance in a thermoacoustic system.
Kabiraj, Lipika; Steinert, Richard; Saurabh, Aditya; Paschereit, Christian Oliver
2015-10-01
We experimentally investigated the noise-induced dynamics of a prototypical thermoacoustic system undergoing a subcritical Hopf bifurcation to limit cycle oscillations. The study was performed prior to the bistable regime. Analysis of the characteristics of pressure oscillations in the combustor and fluctuations in the heat release rate from the flame-the two physical entities involved in thermoacoustic coupling-at increasing levels of noise indicated precursors to the Hopf bifurcation. These precursors were further identified to be a result of coherence resonance.
Electron-electron double resonance (ELDOR) with a loop-gap resonator
NASA Astrophysics Data System (ADS)
Hyde, James S.; Yin, Jun-Jie; Froncisz, W.; Feix, Jimmy B.
Electron-electron double-resonance (ELDOR) experiments on nitroxide-radical-spin-labeled liposomes have been performed using a loop-gap resonator. The signal-to-noise ratio expressed on a molarity basis is 20-fold over the best that has been achieved using a bimodal cavity. This improvement permits ELDOR experiments on spin-labeled plasma membranes of intact cells, as illustrated by a prototype experiment on red blood cells labeled with stearic acid spin label. Moreover, 20 times greater pumping energy density at the sample is achievable for a given incident pump power, permitting ELDOR experiments on less readily saturated systems. Pump and observing frequencies are introduced directly into the loop-gap resonator, which has a relatively low Q, and the pump electron paramagnetic resonance signal is isolated from the receiver using a high Q trap microwave filter.
Parametric Symmetry Breaking in a Nonlinear Resonator
NASA Astrophysics Data System (ADS)
Leuch, Anina; Papariello, Luca; Zilberberg, Oded; Degen, Christian L.; Chitra, R.; Eichler, Alexander
2016-11-01
Much of the physical world around us can be described in terms of harmonic oscillators in thermodynamic equilibrium. At the same time, the far-from-equilibrium behavior of oscillators is important in many aspects of modern physics. Here, we investigate a resonating system subject to a fundamental interplay between intrinsic nonlinearities and a combination of several driving forces. We have constructed a controllable and robust realization of such a system using a macroscopic doubly clamped string. We experimentally observe a hitherto unseen double hysteresis in both the amplitude and the phase of the resonator's response function and present a theoretical model that is in excellent agreement with the experiment. Our work unveils that the double hysteresis is a manifestation of an out-of-equilibrium symmetry breaking between parametric phase states. Such a fundamental phenomenon, in the most ubiquitous building block of nature, paves the way for the investigation of new dynamical phases of matter in parametrically driven many-body systems and motivates applications ranging from ultrasensitive force detection to low-energy computing memory units.
NASA Astrophysics Data System (ADS)
Potapov, Alexey; Epel, Boris; Goldfarb, Daniella
2008-02-01
A new, triple resonance, pulse electron paramagnetic resonance (EPR) sequence is described. It provides spin links between forbidden electron spin transitions (ΔMS=±1, ΔMI≠0) and allowed nuclear spin transitions (ΔMI=±1), thus, facilitating the assignment of nuclear frequencies to their respective electron spin manifolds and paramagnetic centers. It also yields the relative signs of the hyperfine couplings of the different nuclei. The technique is based on the combination of electron-nuclear double resonance (ENDOR) and electron-electron double resonance (ELDOR)-detected NMR experiments in a way similar to the TRIPLE experiment. The feasibility and the information content of the method are demonstrated first on a single crystal of Cu-doped L-histidine and then on a frozen solution of a Cu-histidine complex.
A microwave resonator integrated on a polymer microfluidic chip
NASA Astrophysics Data System (ADS)
Kiss, S. Z.; Rostas, A. M.; Heidinger, L.; Spengler, N.; Meissner, M. V.; MacKinnon, N.; Schleicher, E.; Weber, S.; Korvink, J. G.
2016-09-01
We describe a novel stacked split-ring type microwave (MW) resonator that is integrated into a 10 mm by 10 mm sized microfluidic chip. A straightforward and scalable batch fabrication process renders the chip suitable for single-use applications. The resonator volume can be conveniently loaded with liquid sample via microfluidic channels patterned into the mid layer of the chip. The proposed MW resonator offers an alternative solution for compact in-field measurements, such as low-field magnetic resonance (MR) experiments requiring convenient sample exchange. A microstrip line was used to inductively couple MWs into the resonator. We characterised the proposed resonator topology by electromagnetic (EM) field simulations, a field perturbation method, as well as by return loss measurements. Electron paramagnetic resonance (EPR) spectra at X-band frequencies were recorded, revealing an electron-spin sensitivity of 3.7 ·1011spins ·Hz - 1 / 2G-1 for a single EPR transition. Preliminary time-resolved EPR experiments on light-induced triplet states in pentacene were performed to estimate the MW conversion efficiency of the resonator.
A microwave resonator integrated on a polymer microfluidic chip.
Kiss, S Z; Rostas, A M; Heidinger, L; Spengler, N; Meissner, M V; MacKinnon, N; Schleicher, E; Weber, S; Korvink, J G
2016-09-01
We describe a novel stacked split-ring type microwave (MW) resonator that is integrated into a 10mm by 10mm sized microfluidic chip. A straightforward and scalable batch fabrication process renders the chip suitable for single-use applications. The resonator volume can be conveniently loaded with liquid sample via microfluidic channels patterned into the mid layer of the chip. The proposed MW resonator offers an alternative solution for compact in-field measurements, such as low-field magnetic resonance (MR) experiments requiring convenient sample exchange. A microstrip line was used to inductively couple MWs into the resonator. We characterised the proposed resonator topology by electromagnetic (EM) field simulations, a field perturbation method, as well as by return loss measurements. Electron paramagnetic resonance (EPR) spectra at X-band frequencies were recorded, revealing an electron-spin sensitivity of 3.7·10(11)spins·Hz(-1/2)G(-1) for a single EPR transition. Preliminary time-resolved EPR experiments on light-induced triplet states in pentacene were performed to estimate the MW conversion efficiency of the resonator.
Resonant excitation of whistler waves by a helical electron beam
NASA Astrophysics Data System (ADS)
An, X.; Van Compernolle, B.; Bortnik, J.; Thorne, R. M.; Chen, L.; Li, W.
2016-03-01
Chorus-like whistler mode waves that are known to play a fundamental role in driving radiation belt dynamics are excited on the Large Plasma Device by the injection of a helical electron beam into a cold plasma. The mode structure of the excited whistler wave is identified using a phase correlation technique showing that the waves are excited through a combination of Landau resonance, cyclotron resonance, and anomalous cyclotron resonance. The dominant wave mode excited through cyclotron resonance is quasi-parallel propagating, whereas wave modes excited through Landau resonance and anomalous cyclotron resonance propagate at oblique angles that are close to the resonance cone. An analysis of the linear wave growth rates captures the major observations in the experiment. The results have important implications for the generation process of whistler waves in the Earth's inner magnetosphere.
Elimination of resonance with a switching support
NASA Astrophysics Data System (ADS)
Turkstra, T. P.; Semercigil, S. E.
1991-05-01
An add-on switching support is proposed to limit the vibration of a transmission shaft. Experiments are described achieving amplitude reductions in the order of 75 percent. A simple active on/off control system to restrain the excessive transient vibrations of flexible shafts has been designed. The control can be implemented as an add-on system without interfering with the existing bearing structure. An advantage of such an add-on system is that it can be used in already existing structures which operate at supercritical speeds. A finite element analysis (FEA) technique has been utilized to simulate the dynamic response of the flexible shaft operating at sub and supercritical speeds. The results suggest that a vibration amplitude reduction of 75 percent could be obtained with the actuation of the intelligently switching extra support, which could be referred to as a switching support or a phantom support. Experimental data back up the numerical results, demonstrating the viability of the switching support technique for limiting vibration amplitude. At the motor, an amplitude reduction of 75 percent was achieved with the switching support over the simply supported case. An 80 percent reduction over the triply supported case was achieved. Thus the switching support can be used to instantaneously modify the shaft stiffness and the resonant frequencies so that the excitation speed can never approach a resonant frequency.
Electrodynamics of a ring-shaped spiral resonator
Maleeva, N.; Karpov, A.; Averkin, A.; Fistul, M. V.; Zhuravel, A. P.; Jung, P.; Ustinov, A. V.
2014-02-14
We present analytical, numerical, and experimental investigations of electromagnetic resonant modes of a compact monofilar Archimedean spiral resonator shaped in a ring, with no central part. Planar spiral resonators are interesting as components of metamaterials for their compact deep-subwavelength size. Such resonators couple primarily to the magnetic field component of the incident electromagnetic wave, offering properties suitable for magnetic meta-atoms. Surprisingly, the relative frequencies of the resonant modes follow the sequence of the odd numbers as f{sub 1}:f{sub 2}:f{sub 3}:f{sub 4}… = 1:3:5:7…, despite the nearly identical boundary conditions for electromagnetic fields at the extremities of the resonator. In order to explain the observed spectrum of resonant modes, we show that the current distribution inside the spiral satisfies a particular Carleman type singular integral equation. By solving this equation, we obtain a set of resonant frequencies. The analytically calculated resonance frequencies and the current distributions are in good agreement with experimental data and the results of numerical simulations. By using low-temperature laser scanning microscopy of a superconducting spiral resonator, we compare the experimentally visualized ac current distributions over the spiral with the calculated ones. Theory and experiment agree well with each other. Our analytical model allows for calculation of a detailed three-dimensional magnetic field structure of the resonators.
Electrodynamics of a ring-shaped spiral resonator
NASA Astrophysics Data System (ADS)
Maleeva, N.; Fistul, M. V.; Karpov, A.; Zhuravel, A. P.; Averkin, A.; Jung, P.; Ustinov, A. V.
2014-02-01
We present analytical, numerical, and experimental investigations of electromagnetic resonant modes of a compact monofilar Archimedean spiral resonator shaped in a ring, with no central part. Planar spiral resonators are interesting as components of metamaterials for their compact deep-subwavelength size. Such resonators couple primarily to the magnetic field component of the incident electromagnetic wave, offering properties suitable for magnetic meta-atoms. Surprisingly, the relative frequencies of the resonant modes follow the sequence of the odd numbers as f1:f2:f3:f4… = 1:3:5:7…, despite the nearly identical boundary conditions for electromagnetic fields at the extremities of the resonator. In order to explain the observed spectrum of resonant modes, we show that the current distribution inside the spiral satisfies a particular Carleman type singular integral equation. By solving this equation, we obtain a set of resonant frequencies. The analytically calculated resonance frequencies and the current distributions are in good agreement with experimental data and the results of numerical simulations. By using low-temperature laser scanning microscopy of a superconducting spiral resonator, we compare the experimentally visualized ac current distributions over the spiral with the calculated ones. Theory and experiment agree well with each other. Our analytical model allows for calculation of a detailed three-dimensional magnetic field structure of the resonators.
Frequency division using a micromechanical resonance cascade
NASA Astrophysics Data System (ADS)
Qalandar, K. R.; Strachan, B. S.; Gibson, B.; Sharma, M.; Ma, A.; Shaw, S. W.; Turner, K. L.
2014-12-01
A coupled micromechanical resonator array demonstrates a mechanical realization of multi-stage frequency division. The mechanical structure consists of a set of N sequentially perpendicular microbeams that are connected by relatively weak elastic elements such that the system vibration modes are localized to individual microbeams and have natural frequencies with ratios close to 1:2:⋯:2N. Conservative (passive) nonlinear inter-modal coupling provides the required energy transfer between modes and is achieved by finite deformation kinematics. When the highest frequency beam is excited, this arrangement promotes a cascade of subharmonic resonances that achieve frequency division of 2j at microbeam j for j = 1, …, N. Results are shown for a capacitively driven three-stage divider in which an input signal of 824 kHz is passively divided through three modal stages, producing signals at 412 kHz, 206 kHz, and 103 kHz. The system modes are characterized and used to delineate the range of AC input voltages and frequencies over which the cascade occurs. This narrow band frequency divider has simple design rules that are scalable to higher frequencies and can be extended to a larger number of modal stages.
Anomalous resonance in a nanomechanical biosensor
Gupta, Amit K.; Nair, Pradeep R.; Akin, Demir; Ladisch, Michael R.; Broyles, Steve; Alam, Muhammad A.; Bashir, Rashid
2006-01-01
The decrease in resonant frequency (−Δωr) of a classical cantilever provides a sensitive measure of the mass of entities attached on its surface. This elementary phenomenon has been the basis of a new class of bio-nanomechanical devices as sensing components of integrated microsystems that can perform rapid, sensitive, and selective detection of biological and biochemical entities. Based on classical analysis, there is a widespread perception that smaller sensors are more sensitive (sensitivity ≈ −0.5ωr/mC, where mC is the mass of the cantilever), and this notion has motivated scaling of biosensors to nanoscale dimensions. In this work, we show that the response of a nanomechanical biosensor is far more complex than previously anticipated. Indeed, in contrast to classical microscale sensors, the resonant frequencies of the nanosensor may actually decrease or increase after attachment of protein molecules. We demonstrate theoretically and experimentally that the direction of the frequency change arises from a size-specific modification of diffusion and attachment kinetics of biomolecules on the cantilevers. This work may have broad impact on microscale and nanoscale biosensor design, especially when predicting the characteristics of bio-nanoelectromechanical sensors functionalized with biological capture molecules. PMID:16938886
Resonant Versus Anti-Resonant Tunneling at Carbon Nanotube A-B-A Heterostructures
NASA Technical Reports Server (NTRS)
Mingo, N.; Yang, Liu; Han, Jie; Anantram, M. P.
2001-01-01
Narrow antiresonances going to zero transmission are found to occur for general (2n,0)(n,n)(2n,0) carbon nanotube heterostructures, whereas the complementary configuration, (n,n)(2n,0)(n,n), displays simple resonant tunneling behaviour. We compute examples for different cases, and give a simple explanation for the appearance of antiresonances in one case but not in the other. Conditions and ranges for the occurrence of these different behaviors are stated. The phenomenon of anti-resonant tunneling, which has passed unnoticed in previous studies of nanotube heterostructures, adds up to the rich set of behaviors available to nanotube based quantum effect devices.
Raman Scattering at Resonant or Near-Resonant Conditions: A Generalized Short-Time Approximation
NASA Astrophysics Data System (ADS)
Mohammed, Abdelsalam; Sun, Yu-Ping; Miao, Quan; Ågren, Hans; Gel'mukhanov, Faris
2012-02-01
We investigate the dynamics of resonant Raman scattering in the course of the frequency detuning. The dephasing in the time domain makes the scattering fast when the photon energy is tuned from the absorption resonance. This makes frequency detuning to act as a camera shutter with a regulated scattering duration and provides a practical tool of controlling the scattering time in ordinary stationary measurements. The theory is applied to resonant Raman spectra of a couple of few-mode model systems and to trans-1,3,5-hexatriene and guanine-cytosine (G-C) Watson-Crick base pairs (DNA) molecules. Besides some particular physical effects, the regime of fast scattering leads to a simplification of the spectrum as well as to the scattering theory itself. Strong overtones appear in the Raman spectra when the photon frequency is tuned in the resonant region, while in the mode of fast scattering, the overtones are gradually quenched when the photon frequency is tuned more than one vibrational quantum below the first absorption resonance. The detuning from the resonant region thus leads to a strong purification of the Raman spectrum from the contamination by higher overtones and soft modes and purifies the spectrum also in terms of avoidance of dissociation and interfering fluorescence decay of the resonant state. This makes frequency detuning a very useful practical tool in the analysis of the resonant Raman spectra of complex systems and considerably improves the prospects for using the Raman effect for detection of foreign substances at ultra-low concentrations.
A parity checker circuit based on microelectromechanical resonator logic elements
NASA Astrophysics Data System (ADS)
Hafiz, Md Abdullah Al; Li, Ren; Younis, Mohammad I.; Fariborzi, Hossein
2017-03-01
Micro/nano-electromechanical resonator based logic computation has attracted significant attention in recent years due to its dynamic mode of operation, ultra-low power consumption, and potential for reprogrammable and reversible computing. Here we demonstrate a 4-bit parity checker circuit by utilizing recently developed logic gates based on MEMS resonators. Toward this, resonance frequencies of shallow arch shaped micro-resonators are electrothermally tuned by the logic inputs to constitute the required logic gates for the proposed parity checker circuit. This study demonstrates that by utilizing MEMS resonator based logic elements, complex digital circuits can be realized.
A test resonator for Kagome Hollow-core Photonic Crystal Fibers for resonant rotation sensing
NASA Astrophysics Data System (ADS)
Fsaifes, Ihsan; Feugnet, Gilles; Ravaille, Alexia; Debord, Benoït; Gérôme, Frédéric; Baz, Assaad; Humbert, Georges; Benabid, Fetah; Schwartz, Sylvain; Bretenaker, Fabien
2017-01-01
We build ring resonators to assess the potentialities of Kagome Hollow-Core Photonic Crystal Fibers for future applications to resonant rotation sensing. The large mode diameter of Kagome fibers permits to reduce the free space fiber-to-fiber coupling losses, leading to cavities with finesses of about 30 for a diameter equal to 15 cm. Resonance linewidths of 3.2 MHz with contrasts as large as 89% are obtained. Comparison with 7-cell photonic band gap (PBG) fiber leads to better finesse and contrast with Kagome fiber. Resonators based on such fibers are compatible with the angular random walk required for medium to high performance rotation sensing. The small amount of light propagating in silica should also permit to further reduce the Kerr-induced non-reciprocity by at least three orders of magnitudes in 7-cell Kagome fiber compared with 7-cell PBG fiber.
Magnetic resonance elastography hardware design: a survey.
Tse, Z T H; Janssen, H; Hamed, A; Ristic, M; Young, I; Lamperth, M
2009-05-01
Magnetic resonance elastography (MRE) is an emerging technique capable of measuring the shear modulus of tissue. A suspected tumour can be identified by comparing its properties with those of tissues surrounding it; this can be achieved even in deep-lying areas as long as mechanical excitation is possible. This would allow non-invasive methods for cancer-related diagnosis in areas not accessible with conventional palpation. An actuating mechanism is required to generate the necessary tissue displacements directly on the patient in the scanner and three different approaches, in terms of actuator action and position, exist to derive stiffness measurements. However, the magnetic resonance (MR) environment places considerable constraints on the design of such devices, such as the possibility of mutual interference between electrical components, the scanner field, and radio frequency pulses, and the physical space restrictions of the scanner bore. This paper presents a review of the current solutions that have been developed for MRE devices giving particular consideration to the design criteria including the required vibration frequency and amplitude in different applications, the issue of MR compatibility, actuation principles, design complexity, and scanner synchronization issues. The future challenges in this field are also described.
A hyperpolarized equilibrium for magnetic resonance.
Hövener, Jan-Bernd; Schwaderlapp, Niels; Lickert, Thomas; Duckett, Simon B; Mewis, Ryan E; Highton, Louise A R; Kenny, Stephen M; Green, Gary G R; Leibfritz, Dieter; Korvink, Jan G; Hennig, Jürgen; von Elverfeldt, Dominik
2013-01-01
Nuclear magnetic resonance spectroscopy and imaging (MRI) play an indispensable role in science and healthcare but use only a tiny fraction of their potential. No more than ≈10 p.p.m. of all ¹H nuclei are effectively detected in a 3-Tesla clinical MRI system. Thus, a vast array of new applications lays dormant, awaiting improved sensitivity. Here we demonstrate the continuous polarization of small molecules in solution to a level that cannot be achieved in a viable magnet. The magnetization does not decay and is effectively reinitialized within seconds after being measured. This effect depends on the long-lived, entangled spin-order of parahydrogen and an exchange reaction in a low magnetic field of 10⁻³ Tesla. We demonstrate the potential of this method by fast MRI and envision the catalysis of new applications such as cancer screening or indeed low-field MRI for routine use and remote application.
Energy dissipation in a fluidic nanomechanical resonator
NASA Astrophysics Data System (ADS)
Sader, John; Burg, Thomas; Manalis, Scott
2008-11-01
The fluid-structure interaction of resonating microcantilevers in fluid has been widely studied and is a cornerstone in nanomechanical sensor development. Operation in fluid environments presents significant challenges due to the strong enhancement of fluid damping effects with miniaturization. Recently, Burg et al. [Nature, Vol. 446, 1066 (2007)] proposed a new type of microcantilever device whereby a microfluidic channel was embedded inside the cantilever, which resulted in unprecedented sensitivity. We study the fluid dynamics of these devices by presenting a theoretical model and experimental measurements. Significantly, it is found that energy dissipation in these devices is not a monotonic function of fluid viscosity. A direct consequence is that miniaturization does not necessarily result in degradation in the quality factor, which may indeed be enhanced. This highly desirable feature is unprecedented in current nanomechanical devices and permits direct miniaturization to enhance sensitivity in liquid environments.
A hyperpolarized equilibrium for magnetic resonance
Hövener, Jan-Bernd; Schwaderlapp, Niels; Lickert, Thomas; Duckett, Simon B.; Mewis, Ryan E.; Highton, Louise A. R.; Kenny, Stephen M.; Green, Gary G. R.; Leibfritz, Dieter; Korvink, Jan G.; Hennig, Jürgen; von Elverfeldt, Dominik
2013-01-01
Nuclear magnetic resonance spectroscopy and imaging (MRI) play an indispensable role in science and healthcare but use only a tiny fraction of their potential. No more than ≈10 p.p.m. of all 1H nuclei are effectively detected in a 3-Tesla clinical MRI system. Thus, a vast array of new applications lays dormant, awaiting improved sensitivity. Here we demonstrate the continuous polarization of small molecules in solution to a level that cannot be achieved in a viable magnet. The magnetization does not decay and is effectively reinitialized within seconds after being measured. This effect depends on the long-lived, entangled spin-order of parahydrogen and an exchange reaction in a low magnetic field of 10−3 Tesla. We demonstrate the potential of this method by fast MRI and envision the catalysis of new applications such as cancer screening or indeed low-field MRI for routine use and remote application. PMID:24336292
A resonance based model of biological evolution
NASA Astrophysics Data System (ADS)
Damasco, Achille; Giuliani, Alessandro
2017-04-01
We propose a coarse grained physical model of evolution. The proposed model 'at least in principle' is amenable of an experimental verification even if this looks as a conundrum: evolution is a unique historical process and the tape cannot be reversed and played again. Nevertheless, we can imagine a phenomenological scenario tailored upon state transitions in physical chemistry in which different agents of evolution play the role of the elements of a state transition like thermal noise or resonance effects. The abstract model we propose can be of help for sketching hypotheses and getting rid of some well-known features of natural history like the so-called Cambrian explosion. The possibility of an experimental proof of the model is discussed as well.
Modeling of a resonant heat engine
NASA Astrophysics Data System (ADS)
Preetham, B. S.; Anderson, M.; Richards, C.
2012-12-01
A resonant heat engine in which the piston assembly is replaced by a sealed elastic cavity is modeled and analyzed. A nondimensional lumped-parameter model is derived and used to investigate the factors that control the performance of the engine. The thermal efficiency predicted by the model agrees with that predicted from the relation for the Otto cycle based on compression ratio. The predictions show that for a fixed mechanical load, increasing the heat input results in increased efficiency. The output power and power density are shown to depend on the loading for a given heat input. The loading condition for maximum output power is different from that required for maximum power density.
Classical decoherence in a nanomechanical resonator
NASA Astrophysics Data System (ADS)
Maillet, Olivier; Fefferman, Andrew; Gazizulin, Rasul; Godfrin, Henri; Bourgeois, Olivier; Collin, Eddy; ULT Grenoble Team
Decoherence can be viewed either in its quantum picture, where it stands for the loss of phase coherence of a superposition state, or as its classical equivalent, where the phase of an oscillating signal is smeared due to frequency fluctuations. Little is known about quantum coherence of mechanical systems, as opposed to electromagnetic degrees of freedom. Indeed the bridge between quantum and classical physics is under intense investigation, using in particular classical nanomechanical analogues of quantum phenomena. Here we report on a model experiment in which the coherence of a high quality silicon-nitride mechanical resonator is defined in the classical picture. Its intrinsic properties are characterized over an unprecedentedly large dynamic range. By engineering frequency fluctuations, we can create artificial pure dephasing and study its effects on the dynamics of the system. Finally, we develop the methods to characterize pure dephasing that can be applied to a wide range of mechanical devices.
A simple electron cyclotron resonance ion sourcea)
NASA Astrophysics Data System (ADS)
Welton, R. F.; Moran, T. F.; Feeney, R. K.; Thomas, E. W.
1996-04-01
A simple, all permanent magnet, 2.45 GHz electron cyclotron resonance ion source has been developed for the production of stable beams of low charge state ions from gaseous feed materials. The source can produce ˜1 mA of low energy (3 kV) singly charged ion current in the 10-4 Torr pressure range. The source can also be operated in a more efficient low-pressure mode at an order of magnitude lower pressure. In this latter range, for example, the ionization efficiency of Ar is estimated to be 1% with charge states up to Ar8+ present. Operation in the low-pressure mode requires low power input (˜20 W). These features make the source especially suited for use with small accelerator systems for a number of applications including ion implantation, mass spectrometry, and atomic collision experiments where multiply charged ions are desirable. Design details and performance characteristics of the source are presented.
A search for resonant Z pair production
Boveia, Antonio
2008-12-01
I describe a search for anomalous production of Z pairs through a new massive resonance X in 2.5-2.9 fb^{-1} of p$\\bar{p}$ collisions at √s = 1.96 TeV using the CDFII Detector at the Fermilab Tevatron. I reconstruct Z pairs through their decays to electrons, muons, and quarks. To achieve perhaps the most efficient lepton reconstruction ever used at CDF, I apply a thorough understanding of the detector and new reconstruction software heavily revised for this purpose. In particular, I have designed and employ new general-purpose algorithms for tracking at large η in order to increase muon acceptance. Upon analyzing the unblinded signal samples, I observe no X → ZZ candidates and set upper limits on the production cross section using a Kaluza-Klein graviton-like acceptance.
Nodal resonance in a strong standing wave
NASA Astrophysics Data System (ADS)
Fernández C., David J.; Mielnik, Bogdan
1990-06-01
The motion of charged particles in a standing electromagnetic wave is considered. For amplitudes that are not too high, the wave causes an effect of attraction of particles to the nodal points, resembling the channeling effect reported by Salomon, Dalibard, Aspect, Metcalf, and Cohen-Tannoudji [Phys. Rev. Lett. 59, 1659 (1987)] consistent with the ``high-frequency potential'' of Kapitza [Zh. Eksp. Teor. Fiz. 21, 588 (1951)]. For high-field intensities, however, the nodal points undergo a qualitative metamorphosis, converting themselves from particle attractors into resonant centers. Some chaotic phenomena arise and the description of the oscillating field in terms of an ``effective potential'' becomes inappropriate. The question of a correct Floquet Hamiltonian that could describe the standing wave within this amplitude and frequency regime is open.
Chest magnetic resonance imaging: a protocol suggestion*
Hochhegger, Bruno; de Souza, Vinícius Valério Silveira; Marchiori, Edson; Irion, Klaus Loureiro; Souza Jr., Arthur Soares; Elias Junior, Jorge; Rodrigues, Rosana Souza; Barreto, Miriam Menna; Escuissato, Dante Luiz; Mançano, Alexandre Dias; Araujo Neto, César Augusto; Guimarães, Marcos Duarte; Nin, Carlos Schuler; Santos, Marcel Koenigkam; Silva, Jorge Luiz Pereira e
2015-01-01
In the recent years, with the development of ultrafast sequences, magnetic resonance imaging (MRI) has been established as a valuable diagnostic modality in body imaging. Because of improvements in speed and image quality, MRI is now ready for routine clinical use also in the study of pulmonary diseases. The main advantage of MRI of the lungs is its unique combination of morphological and functional assessment in a single imaging session. In this article, the authors review most technical aspects and suggest a protocol for performing chest MRI. The authors also describe the three major clinical indications for MRI of the lungs: staging of lung tumors; evaluation of pulmonary vascular diseases; and investigation of pulmonary abnormalities in patients who should not be exposed to radiation. PMID:26811555
Resonance tunneling through a nonstationary potential
Sokolovskii, D.G.; Sumetskii, M.Y.
1986-02-01
The authors considerd how the probability of resonance tunneling is changed when there is superimposed on the stationary potential a nonstationary perturbation, which may be greater than or of the order of the width of a level in the well. The influence of nonstationary perturbation of the potential on tunneling was investigated numerically for the model of a barrier of zero radius, in which it was shown that at certain frequencies there can be complete reflection from the barrier. The authors write down quasiclassical solutions of the Schrodinger equation with the considered potential. Matching rules are obtained in neighborhoods of turning points and an equation is derived for the transmission probability amplitude. Quantization rules in the well are presented and an expression for the probability of nonresonance tunneling is given.
Dai, Xiwen; Jing, Xiaodong Sun, Xiaofeng
2015-05-15
The acoustic resonance in a Helmholtz resonator excited by a low Mach number grazing flow is studied theoretically. The nonlinear numerical model is established by coupling the vortical motion at the cavity opening with the cavity acoustic mode through an explicit force balancing relation between the two sides of the opening. The vortical motion is modeled in the potential flow framework, in which the oscillating motion of the thin shear layer is described by an array of convected point vortices, and the unsteady vortex shedding is determined by the Kutta condition. The cavity acoustic mode is obtained from the one-dimensional acoustic propagation model, the time-domain equivalent of which is given by means of a broadband time-domain impedance model. The acoustic resistances due to radiation and viscous loss at the opening are also taken into account. The physical processes of the self-excited oscillations, at both resonance and off-resonance states, are simulated directly in the time domain. Results show that the shear layer exhibits a weak flapping motion at the off-resonance state, whereas it rolls up into large-scale vortex cores when resonances occur. Single and dual-vortex patterns are observed corresponding to the first and second hydrodynamic modes. The simulation also reveals different trajectories of the two vortices across the opening when the first and second hydrodynamic modes co-exist. The strong modulation of the shed vorticity by the acoustic feedback at the resonance state is demonstrated. The model overestimates the pressure pulsation amplitude by a factor 2, which is expected to be due to the turbulence of the flow which is not taken into account. The model neglects vortex shedding at the downstream and side edges of the cavity. This will also result in an overestimation of the pulsation amplitude.
Stochastic resonance in a tristable optomechanical system
NASA Astrophysics Data System (ADS)
Fan, Bixuan; Xie, Min
2017-02-01
In this work we theoretically investigate the stochastic resonance (SR) effect in an optomechanical membrane system subject to two weak signals (one optical field and one mechanical force). The quadratic optomechanical coupling allows us to find a region with tristability where the noise-activated stochastic switching among three stable states occurs and SR phenomena are observed at the cooperation of input signals and noise. We show that the mechanical force and the optical field respectively serve as an additive signal and a multiplicative signal to the membrane position, and they induce completely different SR behaviors. Moreover, when two signals coexist the SR effect can be enhanced, and the beating effect appears in the SR synchronization process with unsynchronized signals.
A novel digital magnetic resonance imaging spectrometer.
Liu, Zhengmin; Zhao, Cong; Zhou, Heqin; Feng, Huanqing
2006-01-01
Spectrometer is the essential part of magnetic resonance imaging (MRI) system. It controls the transmitting and receiving of signals. Many commercial spectrometers are now available. However, they are usually costly and complex. In this paper, a new digital spectrometer based on PCI extensions for instrumentation (PXI) architecture is presented. Radio frequency (RF) pulse is generated with the method of digital synthesis and its frequency and phase are continuously tunable. MR signal acquired by receiver coils is processed by digital quadrature detection and filtered to get the k-space data, which avoid the spectral distortion due to amplitude and phase errors between two channels of traditional detection. Compared to the conventional design, the presented spectrometer is built with general PXI platform and boards. This design works in a digital manner with features of low cost, high performance and accuracy. The experiments demonstrate its efficiency.
Flutist produces four resonances with a single bottle
NASA Astrophysics Data System (ADS)
Ruiz, Michael J.; Boysen, Erika
2017-03-01
In a dramatic physics demonstration, a professional flutist produces four resonances with a 12 ounce Boylan soda bottle solely through her breath control. The 22 cm bottle acts like a Helmholtz resonator for the lowest pitch. The three higher pitches fall near the 3rd, 5th, and 7th harmonics for a 22 cm closed pipe. A video of this remarkable feat is provided (Ruiz 2016 YouTube: Four Resonances with a 12-ounce Soda Bottle (https://youtu.be/ibtVrp2NF_k)). The video also reveals that a flutist can bend resonance pitches by as much as 10% through control of air speed.
Ultrafast electrical control of a resonantly driven single photon source
Cao, Y.; Bennett, A. J. Ellis, D. J. P.; Shields, A. J.; Farrer, I.; Ritchie, D. A.
2014-08-04
We demonstrate generation of a pulsed stream of electrically triggered single photons in resonance fluorescence, by applying high frequency electrical pulses to a single quantum dot in a p-i-n diode under resonant laser excitation. Single photon emission was verified, with the probability of multiple photon emission reduced to 2.8%. We show that despite the presence of charge noise in the emission spectrum of the dot, resonant excitation acts as a “filter” to generate narrow bandwidth photons.
A mechanistic interpretation of the resonant wave-particle interaction
NASA Astrophysics Data System (ADS)
Chim, Chi Yung; O'Neil, Thomas M.
2016-05-01
This paper provides a simple mechanistic interpretation of the resonant wave-particle interaction of Landau. For the simple case of a Langmuir wave in a Vlasov plasma, the non-resonant electrons satisfy an oscillator equation that is driven resonantly by the bare electric field from the resonant electrons, and in the case of wave damping, this complex driver field is of a phase to reduce the oscillation amplitude. The wave-particle resonant interaction also occurs in waves governed by 2D E × B drift dynamics, such as a diocotron wave. In this case, the bare electric field from the resonant electrons causes E × B drift motion back in the core plasma, reducing the amplitude of the wave.
A mechanistic interpretation of the resonant wave-particle interaction
Chim, Chi Yung; O'Neil, Thomas M.
2016-05-15
This paper provides a simple mechanistic interpretation of the resonant wave-particle interaction of Landau. For the simple case of a Langmuir wave in a Vlasov plasma, the non-resonant electrons satisfy an oscillator equation that is driven resonantly by the bare electric field from the resonant electrons, and in the case of wave damping, this complex driver field is of a phase to reduce the oscillation amplitude. The wave-particle resonant interaction also occurs in waves governed by 2D E × B drift dynamics, such as a diocotron wave. In this case, the bare electric field from the resonant electrons causes E × B drift motion back in the core plasma, reducing the amplitude of the wave.
Experimental Verification of Predicted Oscillations Near a Spin Resonance
Morozov, V.S.; Chao, A.W.; Krisch, A.D.; Leonova, M.A.; Raymond, R.S.; Sivers, D.W.; Wong, V.K.; Ganshvili, A.; Gebel, R.; Lehrach, A.; Lorentz, B.; Maier, R.; Prasuhn, D.; Stockhorst, H.; Welsch, D.; Hinterberger, F.; Ulbrich, K.; Schnase, A.; Stephenson, E.J.; Brantjes, N.P.M.; Onderwater, C.J.G.; /Groningen U.
2011-12-06
The Chao matrix formalism allows analytic calculations of a beam's polarization behavior inside a spin resonance. We recently tested its prediction of polarization oscillations occurring in a stored beam of polarized particles near a spin resonance. Using a 1.85?GeV/c polarized deuteron beam stored in COSY, we swept a new rf solenoid's frequency rather rapidly through 400 Hz during 100 ms, while varying the distance between the sweep's end frequency and the central frequency of an rf-induced spin resonance. Our measurements of the deuteron's polarization for sweeps ending near and inside the resonance agree with the Chao formalism's predicted oscillations.
Nonlinear resonance and dynamical chaos in a diatomic molecule driven by a resonant ir field
Berman, G.P.; Bulgakov, E.N.; Holm, D.D. ||||
1995-10-01
We consider the transition from regular motion to dynamical chaos in a classical model of a diatomic molecule which is driven by a circularly polarized resonant ir field. Under the conditions of a nearly two-dimensional case, the Hamiltonian reduces to that for the nonintegrable motion of a charged particle in an electromagnetic wave [A. J. Lichtenberg and M. A. Lieberman, {ital Regular} {ital and} {ital Stochastic} {ital Motion} (Springer-Verlag, City, 1983)]. In the general case, the transition to chaos is connected with the overlapping of vibrational-rotational nonlinear resonances and appears even at rather low radiation field intensity, {ital S}{approx_gt}1 GW/cm{sup 2}. We also discuss the possibility of experimentally observing this transition.
Resonance in a cylindrical wraparound microstrip structure with superstrate
NASA Astrophysics Data System (ADS)
Wong, Kin-Lu; Tsai, Ruenn-Bo; Row, Jeen-Sheen
1994-06-01
Analysis of the resonance problem of a cylindrical wrap-around microstrip structure with superstrate is presented. In this study the rigorous full-wave formulation and Galerkin's method are used. The numerical convergence for the selected sinusoidal basis functions with edge singularity is also discussed. Numerical results of the superstrate loading effects on the real and imaginary parts of complex resonant frequency of the structures as a radiator and as a resonator are calculated and analyzed.
KEPLER-16b: SAFE IN A RESONANCE CELL
Popova, Elena A.; Shevchenko, Ivan I.
2013-06-01
The planet Kepler-16b is known to follow a circumbinary orbit around a system of two main-sequence stars. We construct stability diagrams in the ''pericentric distance-eccentricity'' plane, which show that Kepler-16b is in a hazardous vicinity to the chaos domain-just between the instability ''teeth'' in the space of orbital parameters. Kepler-16b survives, because it is close to the stable half-integer 11/2 orbital resonance with the central binary, safe inside a resonance cell bounded by the unstable 5/1 and 6/1 resonances. The neighboring resonance cells are vacant, because they are ''purged'' by Kepler-16b, due to overlap of first-order resonances with the planet. The newly discovered planets Kepler-34b and Kepler-35b are also safe inside resonance cells at the chaos border.
Kepler-16b: Safe in a Resonance Cell
NASA Astrophysics Data System (ADS)
Popova, Elena A.; Shevchenko, Ivan I.
2013-06-01
The planet Kepler-16b is known to follow a circumbinary orbit around a system of two main-sequence stars. We construct stability diagrams in the "pericentric distance-eccentricity" plane, which show that Kepler-16b is in a hazardous vicinity to the chaos domain—just between the instability "teeth" in the space of orbital parameters. Kepler-16b survives, because it is close to the stable half-integer 11/2 orbital resonance with the central binary, safe inside a resonance cell bounded by the unstable 5/1 and 6/1 resonances. The neighboring resonance cells are vacant, because they are "purged" by Kepler-16b, due to overlap of first-order resonances with the planet. The newly discovered planets Kepler-34b and Kepler-35b are also safe inside resonance cells at the chaos border.
Negative nonlinear damping of a multilayer graphene mechanical resonator
NASA Astrophysics Data System (ADS)
Singh, Vibhor; Shevchuk, Olga; Blanter, Ya. M.; Steele, Gary A.
2016-06-01
We experimentally investigate the nonlinear response of a multilayer graphene resonator using a superconducting microwave cavity to detect its motion. The radiation pressure force is used to drive the mechanical resonator in an optomechanically induced transparency configuration. By varying the amplitudes of drive and probe tones, the mechanical resonator can be brought into a nonlinear limit. Using the calibration of the optomechanical coupling, we quantify the mechanical Duffing nonlinearity. By increasing the drive force, we observe a decrease in the mechanical dissipation rate at large amplitudes, suggesting a negative nonlinear damping mechanism in the graphene resonator. Increasing the optomechanical backaction further, we observe instabilities in the mechanical response.
Liu Yueqiang; Connor, J. W.; Cowley, S. C.; Ham, C. J.; Hastie, R. J.; Hender, T. C.
2012-10-15
A numerical study is carried out, based on a simple toroidal tokamak equilibrium, to demonstrate the radial re-distribution of the electromagnetic torque density, as a result of a rotating resistive plasma (linear) response to a static resonant magnetic perturbation field. The computed electromagnetic torque peaks at several radial locations even in the presence of a single rational surface, due to resonances between the rotating response, in the plasma frame, and both Alfven and sound continuum waves. These peaks tend to merge together to form a rather global torque distribution, when the plasma resistivity is large. The continuum resonance induced net electromagnetic torque remains finite even in the limit of an ideal plasma.
Electromagnetically induced absorption in a three-resonator metasurface system.
Zhang, Xueqian; Xu, Ningning; Qu, Kenan; Tian, Zhen; Singh, Ranjan; Han, Jiaguang; Agarwal, Girish S; Zhang, Weili
2015-05-29
Mimicking the quantum phenomena in metamaterials through coupled classical resonators has attracted enormous interest. Metamaterial analogs of electromagnetically induced transparency (EIT) enable promising applications in telecommunications, light storage, slow light and sensing. Although the EIT effect has been studied extensively in coupled metamaterial systems, excitation of electromagnetically induced absorption (EIA) through near-field coupling in these systems has only been sparsely explored. Here we present the observation of the EIA analog due to constructive interference in a vertically coupled three-resonator metamaterial system that consists of two bright and one dark resonator. The absorption resonance is one of the collective modes of the tripartite unit cell. Theoretical analysis shows that the absorption arises from a magnetic resonance induced by the near-field coupling of the three resonators within the unit cell. A classical analog of EIA opens up opportunities for designing novel photonic devices for narrow-band filtering, absorptive switching, optical modulation, and absorber applications.
NASA Astrophysics Data System (ADS)
Morley, Gavin W.; Brunel, Louis-Claude; van Tol, Johan
2008-06-01
We describe a pulsed electron paramagnetic resonance spectrometer operating at several frequencies in the range of 110-336GHz. The microwave source at all frequencies consists of a multiplier chain starting from a solid state synthesizer in the 12-15GHz range. A fast p-i-n-switch at the base frequency creates the pulses. At all frequencies a Fabry-Pérot resonator is employed and the π /2 pulse length ranges from ˜100ns at 110GHzto˜600ns at 334GHz. Measurements of a single crystal containing dilute Mn2+ impurities at 12T illustrate the effects of large electron spin polarizations. The capabilities also allow for pulsed electron-nuclear double resonance (ENDOR) experiments as demonstrated by Mims ENDOR of K39 nuclei in Cr :K3NbO8.
Resonance patterns in a stadium-shaped microcavity
Lee, Soo-Young; Kurdoglyan, M.S.; Rim, Sunghwan; Kim, Chil-Min
2004-08-01
We investigate resonance patterns in a stadium-shaped microcavity around n{sub c}kR{approx_equal}10, where n{sub c} is the refractive index, k the vacuum wave number, and R the radius of the circular part of the cavity. We find that the patterns of high-Q resonances can be classified, even though the classical dynamics of the stadium system is chaotic. The patterns of the high-Q resonances are consistent with ray dynamical considerations and appear as stationary lasing modes with low pumping rate in a nonlinear dynamical model. All resonance patterns are presented in a finite range of kR.
A dual RF resonator system for high-field functional magnetic resonance imaging of small animals.
Ludwig, R; Bodgdanov, G; King, J; Allard, A; Ferris, C F
2004-01-30
A new apparatus has been developed that integrates an animal restrainer arrangement for small animals with an actively tunable/detunable dual radio-frequency (RF) coil system for in vivo anatomical and functional magnetic resonance imaging of small animals at 4.7 T. The radio-frequency coil features an eight-element microstrip line configuration that, in conjunction with a segmented outer copper shield, forms a transversal electromagnetic (TEM) resonator structure. Matching and active tuning/detuning is achieved through fixed/variable capacitors and a PIN diode for each resonator element. These components along with radio-frequency chokes (RFCs) and blocking capacitors are placed on two printed circuit boards (PCBs) whose copper coated ground planes form the front and back of the volume coil and are therefore an integral part of the resonator structure. The magnetic resonance signal response is received with a dome-shaped single-loop surface coil that can be height-adjustable with respect to the animal's head. The conscious animal is immobilized through a mechanical arrangement that consists of a Plexiglas body tube and a head restrainer. This restrainer has a cylindrical holder with a mouthpiece and position screws to receive and restrain the head of the animal. The apparatus is intended to perform anatomical and functional magnetic resonance imaging in conscious animals such as mice, rats, hamsters, and marmosets. Cranial images acquired from fully conscious rats in a 4.7 T Bruker 40 cm bore animal scanner underscore the feasibility of this approach and bode well to extend this system to the imaging of other animals.
A Convenient Formalism for Auger and Autoionization of Overlapping Resonances
NASA Astrophysics Data System (ADS)
Tabanli, M. M.; Peacher, J. L.; Madison, D. H.
2003-05-01
Following the works of Fano [1], Balashov [2], and Davis and Feldkamp [3], we have developed a general formalism for cross sections near overlapping autoionizing resonances [4]. We show that the effect of the interaction between different resonances can be treated as a correction factor to the isolated resonances treatment of the problem. We present a simple correction factor, which can be calculated using only the energy and the width of the resonances. We have applied our approach to four physically important cases as a representative of two overlapping resonances. Our results indicate that even in the case where the resonances are only somewhat overlapping, the correction factor makes a considerable contribution and the agreement between the relative experimental cross section and the isolated resonances calculation does not necessarily imply that the resonance-resonance interactions are negligible. [1] U. Fano, Phys. Rev. 124,.1866 (1961) [2] V. V. Balashov, S. S. Lipovetsky and V. S. Senashenko, Sov. Phys. JETP 36, 858 (1973) [3] L. C. Davis and L. A. Feldkamp, Phys. Rev B. 15, 2961 (1977) [4] M. M. Tabanli, J. L. Peacher and D. H. Madison, J. Phys. B 36, 217 (2003)
Eriksen, E; Golombeck, M A; Junge, S; Dössel, O
2002-01-01
The aim of this work was the 3D-simulation of a dielectric resonator for high-field-MRI. A 12-rod-bird-cage-resonator was simulated in a first step, in order to verify the capability of the commercial simulation software MAFIA to simulate homogeneous, transversal B-fields in resonators. The second step was the simulation of frequency-independent dielectric ceramic resonators for static magnetic field strengths of 7 T and 12 T (294 MHz and 504 MHz respectively). The results were compared to the measured results of a manufactured TiO2- and a Al2O3-resonator. Only minor deviations showed up. These results led to the conclusion that dielectric resonators for high field MRI can be optimised using numerical field calculation software.
Flutist Produces Four Resonances with a Single Bottle
ERIC Educational Resources Information Center
Ruiz, Michael J.; Boysen, Erika
2017-01-01
In a dramatic physics demonstration, a professional flutist produces four resonances with a 12 ounce Boylan soda bottle solely through her breath control. The 22cm bottle acts like a Helmholtz resonator for the lowest pitch. The three higher pitches fall near the 3rd, 5th, and 7th harmonics for a 22cm closed pipe. A video of this remarkable feat…
Two-color resonant four-wave mixing: a tool for double resonance spectroscopy
NASA Astrophysics Data System (ADS)
Rohlfing, Eric A.; Tobiason, Joseph D.; Dunlop, J. R.; Williams, Skip
1995-09-01
Two-color resonant four-wave mixing (RFWM) shows great promise in a variety of double- resonance applications in molecular spectroscopy and chemical dynamics. One such application is stimulated emission pumping (SEP), which is a powerful method of characterizing ground-state potential energy surfaces in regions of chemical interest. We use time-independent, diagrammatic perturbation theory to identify the resonant terms in the third- order nonlinear susceptibility for each possible scheme by which two-color RFWM can be used for double-resonance spectroscopy. After a spherical tensor analysis we arrive at a signal expression for two-color RFWM that separates the molecular properties from purely laboratory-frame factors. In addition, the spectral response for tuning the DUMP laser in RFWM-SEP is found to be a simple Lorentzian in free-jet experiments. We demonstrate the utility of RFWM-SEP and test our theoretical predictions in experiments on jet-cooled transient molecules. In experiments on C3 we compare the two possible RFWM-SEP processes and show that one is particularly well-suited to the common situation in which the PUMP transition is strong but the DUMP transitions are weak. We obtain RFWM-SEP spectra of the formyl radical, HCO, that probe quasibound vibrational resonances lying above the low threshold for dissociation to H+CO. Varying the polarization of the input beams or PUMP rotational branch produces dramatic effects in the relative intensities of rotational lines in the RFWM-SEP spectra of HCO; these effects are well described by our theoretical analysis. Finally, RFWM-SEP spectra of HCO resonances that are homogeneously broadened by dissociation confirm the predicted lineshape and give widths that are in good agreement with those determined via unsaturated fluorescence depletion SEP.
NASA Astrophysics Data System (ADS)
Leitner, Peter; Heyn, Martin F.; Ivanov, Ivan B.; Kasilov, Sergei V.; Kernbichler, Winfried
2014-06-01
In this paper, the impact of momentum and energy conservation of the collision operator in the kinetic description for Resonant Magnetic Perturbations (RMPs) in a tokamak is studied. The particle conserving differential collision operator of Ornstein-Uhlenbeck type is supplemented with integral parts such that energy and momentum are conserved. The application to RMP penetration in a tokamak shows that energy conservation in the electron collision operator is important for the quantitative description of plasma shielding effects at the resonant surface. On the other hand, momentum conservation in the ion collision operator does not significantly change the results.
Leitner, Peter; Heyn, Martin F.; Kernbichler, Winfried; Ivanov, Ivan B.; Kasilov, Sergei V.
2014-06-15
In this paper, the impact of momentum and energy conservation of the collision operator in the kinetic description for Resonant Magnetic Perturbations (RMPs) in a tokamak is studied. The particle conserving differential collision operator of Ornstein-Uhlenbeck type is supplemented with integral parts such that energy and momentum are conserved. The application to RMP penetration in a tokamak shows that energy conservation in the electron collision operator is important for the quantitative description of plasma shielding effects at the resonant surface. On the other hand, momentum conservation in the ion collision operator does not significantly change the results.
A 64 MHz half-birdcage resonator for clinical imaging
NASA Astrophysics Data System (ADS)
Ballon, D.; Graham, M. C.; Miodownik, S.; Koutcher, J. A.
A radiofrequency resonator whose normal modes correspond to those of a ladder network of finite length is described. When formed into a semicylindrical geometry, the lowest frequency mode of the resulting "half-birdcage" resonator yields a B1 distribution which can be exploited for imaging.
Resonance interatomic energy in a Schwarzschild spacetime
NASA Astrophysics Data System (ADS)
Zhou, Wenting; Yu, Hongwei
2017-08-01
We study, in the Schwarzschild spacetime, the resonance interatomic energy (RIE) of two static identical atoms with an interatomic separation L along the radial direction and correlated by a symmetric/antisymmetric entangled state. The atoms are assumed to be coupled to massless scalar fields in the Boulware, Unruh, and Hartle-Hawking vacua, and approximate analytical results are obtained both at infinity and near the horizon. Our results show that at infinity, the RIE approaches that in a flat spacetime, while, near the horizon, they can deviate dramatically from each other. Besides, different from other atomic radiative properties such as the Lamb shift of a single atom or the interatomic energy between two uncorrelated atoms, which can be obviously affected by the thermal character of quantum fields, the RIE of two atoms in a symmetric/antisymmetric entangled state in the Boulware, Unruh, and Hartle-Hawking vacua are exactly the same as a result of the fact that the RIE of two such atoms depends only on the atomic self-reaction, i.e., it does not feel the vacuum fluctuations. This suggests that the RIE of two static atoms in a symmetric/antisymmetric entangled state outside a black hole is oblivious to the Hawking radiation, in contrast to those uncorrelated atoms.
A comparison of Lorentz, planetary gravitational, and satellite gravitational resonances
NASA Technical Reports Server (NTRS)
Hamilton, Douglas P.
1994-01-01
We consider a charged dust grain whose orbital motion is dominated by a planet's point-source gravity, but perturbed by higher-order terms in the planet's gravity field as well as by the Lorentz force arising from an asymmetric planetary magnetic field. Perturbations to Keplerian orbits due to a nonspherical gravity field are expressed in the traditional way: in terms of a disturbing function which can be expanded in a series of spherical harmonics (W. M. Kaula, 1966). In order to calculate the electromagnetic perturbation, we first write the Lorentz force in terms of the orbital elements and then substitute it into Gauss' perturbation equations. We use our result to derive strengths of Lorentz resonances and elucidate their properties. In particular, we compare Lorentz resonances to two types of gravitational resonances: those arising from periodic tugs of a satellite and those due to the attraction of an arbitrarily shaped planet. We find that Lorentz resonances share numerous properties with their gravitational counterparts and show, using simple physical arguments, that several of these patterns are fundamental, applying not only to our expansions, but to all quantities expressed in terms of orbital elements. Some of these patterns have been previously called 'd'Alembert rules' for satellite resonances. Other similarities arise because, to first-order in the perturbing force, the three problems share an integral of the motion. Yet there are also differences; for example, first-order inclination resonances exist for perturbations arising from planetary gravity and from the Lorentz force, but not for those due to an orbiting satellite. Finally, we provide a heuristic treatment of a particle's orbital evolution under the influence of drag and resonant forces. Particles brought into mean-motion resonances experience either trapping or resonant 'jumps,' depending on the direction from which the resonance is approached. We show that this behavior does not depend on
Baskan, Ozdil; Erol, Cengiz; Sahingoz, Yusuf
2016-01-01
Portal biliopathy (PB) is a rare disorder, characterized by biliary ductal and gallbladder wall abnormalities seen in patients with portal hypertension. It most commonly occurs due to idiopathic extrahepatic portal vein obstruction (EHPVO). The abnormalities consist mainly of bile duct compression, stenoses, fibrotic strictures and dilation of both extrahepatic and intrahepatic bile ducts, as well as gallbladder varices. PB may mimic cholangiocarcinoma, sclerosing cholangitis, or choledocholithiasis. Misdiagnosis can be avoided using appropriate imaging modalities to prevent complications. We present the magnetic resonance imaging (MRI) and magnetic resonance cholangiography (MRCP) features of three patients with PB. PMID:25216728
Gyüre, B.; Márkus, B. G.; Bernáth, B.; Simon, F.; Murányi, F.
2015-09-15
We present a novel method to determine the resonant frequency and quality factor of microwave resonators which is faster, more stable, and conceptually simpler than the yet existing techniques. The microwave resonator is pumped with the microwave radiation at a frequency away from its resonance. It then emits an exponentially decaying radiation at its eigen-frequency when the excitation is rapidly switched off. The emitted microwave signal is down-converted with a microwave mixer, digitized, and its Fourier transformation (FT) directly yields the resonance curve in a single shot. Being a FT based method, this technique possesses the Fellgett (multiplex) and Connes (accuracy) advantages and it conceptually mimics that of pulsed nuclear magnetic resonance. We also establish a novel benchmark to compare accuracy of the different approaches of microwave resonator measurements. This shows that the present method has similar accuracy to the existing ones, which are based on sweeping or modulating the frequency of the microwave radiation.
NASA Astrophysics Data System (ADS)
Gyüre, B.; Márkus, B. G.; Bernáth, B.; Murányi, F.; Simon, F.
2015-09-01
We present a novel method to determine the resonant frequency and quality factor of microwave resonators which is faster, more stable, and conceptually simpler than the yet existing techniques. The microwave resonator is pumped with the microwave radiation at a frequency away from its resonance. It then emits an exponentially decaying radiation at its eigen-frequency when the excitation is rapidly switched off. The emitted microwave signal is down-converted with a microwave mixer, digitized, and its Fourier transformation (FT) directly yields the resonance curve in a single shot. Being a FT based method, this technique possesses the Fellgett (multiplex) and Connes (accuracy) advantages and it conceptually mimics that of pulsed nuclear magnetic resonance. We also establish a novel benchmark to compare accuracy of the different approaches of microwave resonator measurements. This shows that the present method has similar accuracy to the existing ones, which are based on sweeping or modulating the frequency of the microwave radiation.
A desktop magnetic resonance imaging system.
Wright, Steven M; Brown, David G; Porter, Jay R; Spence, David C; Esparza, Emilio; Cole, David C; Huson, F Russell
2002-01-01
Modern magnetic resonance imaging (MRI) systems consist of several complex, high cost subsystems. The cost and complexity of these systems often makes them impractical for use as routine laboratory instruments, limiting their use to hospitals and dedicated laboratories. However, advances in the consumer electronics industry have led to the widespread availability of inexpensive radio-frequency integrated circuits with exceptional abilities. We have developed a small, low-cost MR system derived from these new components. When combined with inexpensive desktop magnets, this type of MR scanner has the promise of becoming standard laboratory equipment for both research and education. This paper describes the development of a prototype desktop MR scanner utilizing a 0.21 T permanent magnet with an imaging region of approximately 2 cm diameter. The system uses commercially available components where possible and is programmed in LabVIEW software. Results from 3D data sets of resolution phantoms and fixed, newborn mice demonstrate the capability of this system to obtain useful images from a system constructed for approximately $13,500.
A possible resonance mechanism of earthquakes
NASA Astrophysics Data System (ADS)
Flambaum, V. V.; Pavlov, B. S.
2016-01-01
It had been observed by Linkov et al. (Doklady Academii Nauk, Physics of Earth, 313, 23-25 1992) that there exist periodic 4-6 h pulses of ˜200 μHz seismogravitational 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. The beating transfers the oscillation energy from the remote zone of the tectonic plate to the active zone, triggering the earthquake. Oscillation frequencies of the plate and ones of the active zone are tuned to a resonance by an additional compression applied to the active zone due to collision of neighboring plates or the magma flow in the liquid underlay of the asthenosphere (the upper mantle). In the case when there are three or more SGO with incommensurable difference frequencies ω m - ω n , the SGO beating pattern looks quasi-random, thus masking the non-random nature of the beating process. Nevertheless, we are able to discuss a possibility of the short-term earthquakes predictions based on an accurate monitoring of the beating dynamics.
A SAW resonator with two-dimensional reflectors.
Solal, Marc; Gratier, Julien; Kook, Taeho
2010-01-01
It is known that a part of the loss of leaky SAW resonators is due to radiation of acoustic energy in the bus-bars. Many researchers are working on so-called phononic crystals. A 2-D grating of very strong reflectors allows these devices to fully reflect, for a given frequency band, any incoming wave. A new device based on the superposition of a regular SAW resonator and a 2-D periodic grating of reflectors is proposed. Several arrangements and geometries of the reflectors were studied and compared experimentally on 48 degrees rotated Y-cut lithium tantalate. In particular, a very narrow aperture (7.5 lambda) resonator was manufactured in the 900 MHz range. Because of its small size, this resonator has a resonance Q of only 575 when using the standard technology, whereas a resonance Q of 1100 was obtained for the new device without degradation of the other characteristics. Because of the narrow aperture, the admittance of the standard resonator showed a very strong parasitic above the resonance frequency, whereas this effect is drastically reduced for the new device. These results demonstrate the feasibility of the new approach.
A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER)
NASA Astrophysics Data System (ADS)
Garbacz, Piotr; Fischer, Peer; Krämer, Steffen
2016-09-01
Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the 19F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.
A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER).
Garbacz, Piotr; Fischer, Peer; Krämer, Steffen
2016-09-14
Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the (19)F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.
Shear waves in a cubic nonlinear inhomogeneous resonator
NASA Astrophysics Data System (ADS)
Krit, Timofey B.; Andreev, Valery G.; Sapozhnikov, Oleg A.
2012-09-01
We study finite-amplitude shear waves in one-dimensional resonator represented by a layer of rubber-like medium with inhomogeneities in the form of through holes made on the side face. The holes are parallel to the bases and perpendicular to the direction of vibrations. Two different configurations of the resonator: with holes at the bottom and at the top are studied. A rigid plate of finite mass is fixed on the upper surface. The lower boundary of the layer oscillates harmonically with a given acceleration. The equation of motion of particles in the resonator was found using the model of medium with one relaxation time, and a cubic dependence of the shear modulus of deformation. The measurements were performed in a resonator in the form of a rectangular parallelepiped of 15 mm thickness made of a rubber-like polymer plastisol. The linear shear modulus and shear viscosity of the polymer at the first resonant frequency were determined using the finite element method. The amplitudes of the oscillations in the resonator reached a point where the maximum shear strain in the resonator is 0.4 - 0.6, making it possible to observe nonlinear effects. The evolution of the resonance curves at different amplitudes of acceleration was investigated. A harmonic analysis of the acceleration profiles of the upper boundary was performed. The dependence of nonlinear effects on the holes position was studied.
Proposal of a micromagnetic standard problem for ferromagnetic resonance simulations
NASA Astrophysics Data System (ADS)
Baker, Alexander; Beg, Marijan; Ashton, Gregory; Albert, Maximilian; Chernyshenko, Dmitri; Wang, Weiwei; Zhang, Shilei; Bisotti, Marc-Antonio; Franchin, Matteo; Hu, Chun Lian; Stamps, Robert; Hesjedal, Thorsten; Fangohr, Hans
2017-01-01
Nowadays, micromagnetic simulations are a common tool for studying a wide range of different magnetic phenomena, including the ferromagnetic resonance. A technique for evaluating reliability and validity of different micromagnetic simulation tools is the simulation of proposed standard problems. We propose a new standard problem by providing a detailed specification and analysis of a sufficiently simple problem. By analyzing the magnetization dynamics in a thin permalloy square sample, triggered by a well defined excitation, we obtain the ferromagnetic resonance spectrum and identify the resonance modes via Fourier transform. Simulations are performed using both finite difference and finite element numerical methods, with OOMMF and Nmag simulators, respectively. We report the effects of initial conditions and simulation parameters on the character of the observed resonance modes for this standard problem. We provide detailed instructions and code to assist in using the results for evaluation of new simulator tools, and to help with numerical calculation of ferromagnetic resonance spectra and modes in general.
Diphoton resonance from a warped extra dimension
NASA Astrophysics Data System (ADS)
Bauer, Martin; Hörner, Clara; Neubert, Matthias
2016-07-01
We argue that extensions of the Standard Model (SM) with a warped extra dimension, which successfully address the hierarchy and flavor problems of elementary particle physics, can provide an elegant explanation of the 750 GeV diphoton excess recently reported by ATLAS and CMS. A gauge-singlet bulk scalar with {O} (1) couplings to fermions is identified as the new resonance S, and the vector-like Kaluza-Klein excitations of the SM quarks and leptons mediate its loop-induced couplings to photons and gluons. The electroweak gauge symmetry almost unambiguously dictates the bulk matter content and hence the hierarchies of the Sto γ γ, W W,ZZ,Zγ, toverline{t} and dijet decay rates. We find that the S → Zγ decay mode is strongly suppressed, such that Br( S → Zγ) /Br( S → γγ) < 0 .1. The hierarchy problem for the new scalar boson is solved in analogy with the Higgs boson by localizing it near the infrared brane. The infinite sums over the Kaluza-Klein towers of fermion states converge and can be calculated in closed form with a remarkably simple result. Reproducing the observed pp → S → γγ signal requires Kaluza-Klein masses in the multi-TeV range, consistent with bounds from flavor physics and electroweak precision observables.
Cavitation resonance in the draft tube of a turbine
Pei she yi
1995-12-31
This paper presents a further analysis of {open_quotes}An Experimental Investigation on The Cavitation Pressure Pulsations in The Draft Tube of A Turbine{close_quotes}. The emphasis is put on the effect of the cavitation resonance. The mechanism of formation and the characteristics of the pressure pulsation of die cavitation resonance are discussed based on the statistical analysis in the paper.
Classical decoherence in a nanomechanical resonator
NASA Astrophysics Data System (ADS)
Maillet, O.; Vavrek, F.; Fefferman, A. D.; Bourgeois, O.; Collin, E.
2016-07-01
Decoherence is an essential mechanism that defines the boundary between classical and quantum behaviours, while imposing technological bounds for quantum devices. Little is known about quantum coherence of mechanical systems, as opposed to electromagnetic degrees of freedom. But decoherence can also be thought of in a purely classical context, as the loss of phase coherence in the classical phase space. Indeed the bridge between quantum and classical physics is under intense investigation, using, in particular, classical nanomechanical analogues of quantum phenomena. In the present work, by separating pure dephasing from dissipation, we quantitatively model the classical decoherence of a mechanical resonator: through the experimental control of frequency fluctuations, we engineer artificial dephasing. Building on the fruitful analogy introduced between spins/quantum bits and nanomechanical modes, we report on the methods available to define pure dephasing in these systems, while demonstrating the intrinsic almost-ideal properties of silicon nitride beams. These experimental and theoretical results, at the boundary between classical nanomechanics and quantum information fields, are prerequisite in the understanding of decoherence processes in mechanical devices, both classical and quantum.
Shear waves in a resonator with cubic nonlinearity
NASA Astrophysics Data System (ADS)
Andreev, V. G.; Krit, T. B.; Sapozhnikov, O. A.
2011-11-01
Shear waves with finite amplitude in a one-dimensional resonator in the form of a layer of a rubber-like medium with a rigid plate of finite mass at the upper surface of the layer are investigated. The lower boundary of the layer oscillates according to a harmonic law with a preset acceleration. The equation of motion for particles in a resonator is determined using a model of a medium with a single relaxation time and cubical dependence of the shear modulus on deformation. The amplitude and form of shear waves in a resonator are calculated numerically by the finite difference method at shifted grids. Resonance curves are obtained at different acceleration amplitudes at the lower boundary of a layer. It is demonstrated that, as the oscillation amplitude in the resonator grows, the value of the resonance frequency increases and the shape of the resonance curve becomes asymmetrical. At sufficiently large amplitudes, a bistability region is observed. Measurements were conducted with a resonator, where a layer with the thickness of 15 mm was manufactured of a rubber-like polymer called plastisol. The shear modulus of the polymer at small deformations and the nonlinearity coefficient were determined according to the experimental dependence of mechanical stress on shear deformation. Oscillation amplitudes in the resonator attained values when the maximum shear deformations in the layer were 0.4-0.6, which provided an opportunity to observe nonlinear effects. Measured dependences of the resonance frequency on the oscillation amplitude corresponded to the calculated ones that were obtained at a smaller value of the nonlinear coefficient.
A Composite Capacitor/Inductor Assembly for Resonant Circuits
NASA Astrophysics Data System (ADS)
Hull, J. P.; Scholfield, D. W.
2001-06-01
Resonant structures are of interest due to their ability to produce oscillatory voltages in circuits. Past resonant structures have typically been designed using a lumped element capacitor for energy storage and a separate inductor. A composite capacitor/inductor assembly has been developed which merges the capacitance utilized for energy storage into the inductor, creating a consolidated electrical component. Composite capacitor/inductor assemblies are of interest due to the ability of these devices to produce resonant responses with one half the number of parts required by more traditional resonant structures. This composite capacitor/inductor could be utilized in applications of frequency band suppression or frequency band pass for frequencies in excess of 100 MHz, or where a resonant circuit is required to reside in an area of minimum space - such as a printed circuit board or an integrated circuit. The device and the mathematical treatment to predict the device's performance are described.
Zeng, Kai; Hu, Youwang; Deng, Guiling; Sun, Xiaoyan; Su, Wenyi; Lu, Yunpeng; Duan, Ji’an
2017-01-01
The eigenfrequency of a resonator plays a significant role in the operation of a cylindrical shell vibrating gyroscope, and trimming is aimed at eliminating the frequency split that is the difference of eigenfrequency between two work modes. In this paper, the effects on eigenfrequency under resonator-top trimming methods that trim the top of the resonator wall are investigated by simulation and experiments. Simulation results show that the eigenfrequency of the trimmed mode increases in the holes-trimming method, whereas it decreases in the grooves-trimming method. At the same time, the untrimmed modes decrease in both holes-trimming and grooves-trimming methods. Moreover, grooves-trimming is more efficient than holes-trimming, which indicates that grooves-trimming can be a primary trimming method, and holes-trimming can be a precision trimming method. The rigidity condition after grooves-trimming is also studied to explain the variation of eigenfrequency. A femtosecond laser is employed in the resonator trimming experiment by the precise ablation of the material. Experimental results are in agreement with the simulation results. PMID:28869507
A Wire Crossed-Loop-Resonator for Rapid Scan EPR.
Rinard, George A; Quine, Richard W; Biller, Joshua R; Eaton, Gareth R
2010-04-09
A crossed-loop (orthogonal mode) resonator (CLR) was constructed of fine wire to achieve design goals for rapid scan in vivo EPR imaging at VHF frequencies (in practice, near 250 MHz). This application requires the resonator to have a very open design to facilitate access to the animal for physiological support during the image acquisition. The rapid scan experiment uses large amplitude magnetic field scans, and sufficiently large resonator and detection bandwidths to record the rapidly-changing signal response. Rapid-scan EPR is sensitive to RF/microwave source noise and to baseline changes that are coherent with the field scan. The sensitivity to source noise is a primary incentive for using a CLR to isolate the detected signal from the RF source noise. Isolation from source noise of 44 and 47 dB was achieved in two resonator designs. Prior results showed that eddy currents contribute to background problems in rapid scan EPR, so the CLR design had to minimize conducting metal components. Using fine (AWG 38) wire for the resonators decreased eddy currents and lowered the resonator Q, thus providing larger resonator bandwidth. Mechanical resonances at specific scan frequencies are a major contributor to rapid scan backgrounds.
Phase Matching of Diverse Modes in a WGM Resonator
NASA Technical Reports Server (NTRS)
Savchenkov, Anatoliy; Strekalov, Dmitry; Yu, Nan; Matsko, Andrey; Mohageg, Makan; Maleki, Lute
2008-01-01
Phase matching of diverse electromagnetic modes (specifically, coexisting optical and microwave modes) in a whispering-gallery-mode (WGM) resonator has been predicted theoretically and verified experimentally. Such phase matching is necessary for storage of microwave/terahertz and optical electromagnetic energy in the same resonator, as needed for exploitation of nonlinear optical phenomena. WGM resonators are used in research on nonlinear optical phenomena at low optical intensities and as a basis for design and fabrication of novel optical devices. Examples of nonlinear optical phenomena recently demonstrated in WGM resonators include low-threshold Raman lasing, optomechanical oscillations, frequency doubling, and hyperparametric oscillations. The present findings regarding phase matching were made in research on low-threshold, strongly nondegenerate parametric oscillations in lithium niobate WGM resonators. The principle of operation of such an oscillator is rooted in two previously observed phenomena: (1) stimulated Raman scattering by polaritons in lithium niobate and (2) phase matching of nonlinear optical processes via geometrical confinement of light. The oscillator is partly similar to terahertz oscillators based on lithium niobate crystals, the key difference being that a novel geometrical configuration of this oscillator supports oscillation in the regime. The high resonance quality factors (Q values) typical of WGM resonators make it possible to achieve oscillation at a threshold signal level much lower than that in a non-WGM-resonator lithium niobate crystal.
Bifurcation and resonance in a fractional Mathieu-Duffing oscillator
NASA Astrophysics Data System (ADS)
Yang, J. H.; Sanjuán, Miguel A. F.; Liu, H. G.
2015-11-01
The bifurcation and resonance phenomena are investigated in a fractional Mathieu-Duffing oscillator which contains a fast parametric excitation and a slow external excitation. We extend the method of direct partition of motions to evaluate the response for the parametrically excited system. Besides, we propose a numerical method to simulate different types of local bifurcation of the equilibria. For the nonlinear dynamical behaviors of the considered system, the linear stiffness coefficient is a key factor which influences the resonance phenomenon directly. Moreover, the fractional-order damping brings some new results that are different from the corresponding results in the ordinary Mathieu-Duffing oscillator. Especially, the resonance pattern, the resonance frequency and the resonance magnitude depend on the value of the fractional-order closely.
The Frahm Resonance Apparatus: Variations on a Theme
ERIC Educational Resources Information Center
Daffron, John A.; Greenslade, Thomas B., Jr.
2013-01-01
The Frahm resonance principle, in which resonating reeds indicate the frequency of mechanical or electrical oscillations, is a hardy perennial. In this note we will give some history, show some original apparatus, and show how it may be reproduced with relatively little effort.
The Frahm Resonance Apparatus: Variations on a Theme
ERIC Educational Resources Information Center
Daffron, John A.; Greenslade, Thomas B., Jr.
2013-01-01
The Frahm resonance principle, in which resonating reeds indicate the frequency of mechanical or electrical oscillations, is a hardy perennial. In this note we will give some history, show some original apparatus, and show how it may be reproduced with relatively little effort.
The Frahm Resonance Apparatus: Variations on a Theme
NASA Astrophysics Data System (ADS)
Daffron, John A.; Greenslade, Thomas B.
2013-09-01
The Frahm resonance principle, in which resonating reeds indicate the frequency of mechanical or electrical oscillations, is a hardy perennial. In this note we will give some history, show some original apparatus, and show how it may be reproduced with relatively little effort.
Sidabras, Jason W.; Varanasi, Shiv K.; Hyde, James S.; Mett, Richard R.; Swarts, Steven G.; Swartz, Harold M.
2014-10-15
A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg{sup 2+} doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.
Sidabras, Jason W.; Varanasi, Shiv K.; Mett, Richard R.; Swarts, Steven G.; Swartz, Harold M.; Hyde, James S.
2014-01-01
A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg2+ doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown. PMID:25362434
Sidabras, Jason W; Varanasi, Shiv K; Mett, Richard R; Swarts, Steven G; Swartz, Harold M; Hyde, James S
2014-10-01
A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg(2+) doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.
NASA Astrophysics Data System (ADS)
Sidabras, Jason W.; Varanasi, Shiv K.; Mett, Richard R.; Swarts, Steven G.; Swartz, Harold M.; Hyde, James S.
2014-10-01
A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg2+ doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.
Optimized coplanar waveguide resonators for a superconductor–atom interface
Beck, M. A. Isaacs, J. A.; Booth, D.; Pritchard, J. D.; Saffman, M.; McDermott, R.
2016-08-29
We describe the design and characterization of superconducting coplanar waveguide cavities tailored to facilitate strong coupling between superconducting quantum circuits and single trapped Rydberg atoms. For initial superconductor–atom experiments at 4.2 K, we show that resonator quality factors above 10{sup 4} can be readily achieved. Furthermore, we demonstrate that the incorporation of thick-film copper electrodes at a voltage antinode of the resonator provides a route to enhance the zero-point electric fields of the resonator in a trapping region that is 40 μm above the chip surface, thereby minimizing chip heating from scattered trap light. The combination of high resonator quality factor and strong electric dipole coupling between the resonator and the atom should make it possible to achieve the strong coupling limit of cavity quantum electrodynamics with this system.
Optimized coplanar waveguide resonators for a superconductor-atom interface
NASA Astrophysics Data System (ADS)
Beck, M. A.; Isaacs, J. A.; Booth, D.; Pritchard, J. D.; Saffman, M.; McDermott, R.
2016-08-01
We describe the design and characterization of superconducting coplanar waveguide cavities tailored to facilitate strong coupling between superconducting quantum circuits and single trapped Rydberg atoms. For initial superconductor-atom experiments at 4.2 K, we show that resonator quality factors above 104 can be readily achieved. Furthermore, we demonstrate that the incorporation of thick-film copper electrodes at a voltage antinode of the resonator provides a route to enhance the zero-point electric fields of the resonator in a trapping region that is 40 μm above the chip surface, thereby minimizing chip heating from scattered trap light. The combination of high resonator quality factor and strong electric dipole coupling between the resonator and the atom should make it possible to achieve the strong coupling limit of cavity quantum electrodynamics with this system.
Tunable resonant transmission of electromagnetic waves through a magnetized plasma.
Kee, Chul-Sik; Li, Shou-Zhe; Kim, Kihong; Lim, H
2003-03-01
We theoretically investigate the resonant transmission of circularly polarized electromagnetic waves in the electromagnetic stop band of a magnetized plasma slab using the invariant embedding method. The frequency and quality factor of the resonant mode for the right-handed (left-handed) circularly polarized wave created by inserting a dielectric layer into the plasma increase (decrease) as the magnitude of the external magnetic field increases. These phenomena are compared with the characteristics of resonant modes in metallic and dielectric Fabry-Perot resonators to show that they are due to the change of plasma reflectivity. We also discuss the damping effect due to the collisions of the constituent particles of the plasma on the resonant transmission of circularly polarized waves.
Dispersive Thermometry with a Josephson Junction Coupled to a Resonator
NASA Astrophysics Data System (ADS)
Saira, O.-P.; Zgirski, M.; Viisanen, K. L.; Golubev, D. S.; Pekola, J. P.
2016-08-01
We embed a small Josephson junction in a microwave resonator that allows simultaneous dc biasing and dispersive readout. Thermal fluctuations drive the junction into phase diffusion and induce a temperature-dependent shift in the resonance frequency. By sensing the thermal noise of a remote resistor in this manner, we demonstrate primary thermometry in the range of 300 mK to below 100 mK, and high-bandwidth (7.5 MHz) operation with a noise-equivalent temperature of better than 10 μ K /√{Hz } . At a finite bias voltage close to a Fiske resonance, amplification of the microwave probe signal is observed. We develop an accurate theoretical model of our device based on the theory of dynamical Coulomb blockade.
Martin, S J; Bandey, H L; Cernosek, R W; Hillman, A R; Brown, M J
2000-01-01
We derive a lumped-element, equivalent-circuit model for the thickness-shear mode (TSM) resonator with a viscoelastic film. This modified Butterworth-Van Dyke model includes in the motional branch a series LCR resonator, representing the quartz resonance, and a parallel LCR resonator, representing the film resonance. This model is valid in the vicinity of film resonance, which occurs when the acoustic phase shift across the film is an odd multiple of pi/2 rad. For low-loss films, this model accurately predicts the frequency changes and damping that arise at resonance and is a reasonable approximation away from resonance. Elements of the parallel LCR resonator are explicitly related to film properties and can be interpreted in terms of elastic energy storage and viscous power dissipation. The model leads to a simple graphical interpretation of the coupling between the quartz and film resonances and facilitates understanding of the resulting responses. These responses are compared with predictions from the transmission-line and Sauerbrey models.
Magnetic resonance elastometry using a single-sided permanent magnet
NASA Astrophysics Data System (ADS)
Tan, Carl S.; Marble, Andrew E.; Ono, Yuu
2012-04-01
In this paper, we describe a magnetic resonance method of measuring material elasticity using a single-sided magnet with a permanent static field gradient. This method encodes sample velocity in a reciprocal space using Hahn spin-echoes with variable timing. The experimental results show a strong correlation between magnetic resonance signal attenuation and elasticity when an oscillating force is applied on the sample. This relationship in turn provides us with information about the displacement velocity experienced by the sample, which is inversely proportional to Young's modulus. The proposed method shows promise in offering a portable and cost-effective magnetic resonance elastography system.
Conjecture Regarding a Possible nnΛ Resonance
NASA Astrophysics Data System (ADS)
Gibson, B. F.; Afnan, I. R.
The question of whether there may exist a resonance in the nnΛ system is addressed. A rank-one separable potential formulation of the Hamiltonian is utilized. We examine the eigenvalues of the kernel of the relevant Faddeev equations in the complex energy plane in order that we may analytically continue the kernel onto the second Riemann energy sheet. In particular, we follow the largest eigenvalue as the nΛ potentials are scaled and the pole in the nnΛ continuum evolves from a sub-threshold resonance into a physically observable resonance and then into a bound state as the scale factor is increased.
Substrate effect on aperture resonances in a thin metal film.
Kang, J H; Choe, Jong-Ho; Kim, D S; Park, Q-Han
2009-08-31
We present a simple theoretical model to study the effect of a substrate on the resonance of an aperture in a thin metal film. The transmitted energy through an aperture is shown to be governed by the coupling of aperture waveguide mode to the incoming and the outgoing electromagnetic waves into the substrate region. Aperture resonance in the energy transmission thus depends critically on the refractive index of a substrate. We explain the substrate effect on aperture resonance in terms of destructive interference among evanescent modes or impedance mismatch. Our model shows an excellent agreement with a rigorous FDTD calculation and is consistent with previous experimental observations.
[Cross-modal stochastic resonance--a special multisensory integration].
Liu, Jie; Ai, Leit; Lou, Kewet; Liu, Jun
2010-08-01
Cross-modal stochastic resonance is a ubiquitous phenomenon, that is, a weak signal from one sensory pathway can be enhanced by the noise from a different sensory pathway. It is a special multisensory integration (MI) that can not be explained by the inverse-effectiveness rule. According to cross-modal stochastic resonance, the detection of signal is an inverted U-like function of the intensity of noise at different levels. In this paper, we reviewed the research of cross-modal stochastic resonance and put forward some possible explanations for it. These efforts raise a new idea for neural encoding and information processing of the brain.
Quantum chaos of atoms in a resonator driven by an external resonant field
Berman, G.P.; Bulgakov, E.N.; Holm, D.D. Kirensky Institute of Physics, Research Educational Center for Nonlinear Processes at Krasnoyarsk Polytechnical Institute, Theoretical Department at Krasnoyarsk State University, 660036, Krasnoyarsk Theoretical Division, MS-B284, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 )
1994-06-01
A system of [ital N] two-level atoms in a resonator is considered interacting with a resonant eigenmode field and with an external coherent field, with a frequency slightly different from the frequency of the atomic transition. A model Hamiltonian is constructed for describing the slow quantum dynamics of the system, and a set of closed [ital c]-number equations for time-dependent quantum expectation values is derived in the boson and spin coherent states. In the region of parameters for developed chaos in the semiclassical limit (when the radiation field is considered classically) we show that the semiclassical approximation is violated by quantum effects at the time scale [tau][sub [h bar
Nonlinear Resonance Islands and Modulational Effects in a Proton Synchrotron
Satogata, Todd Jeffrey
1993-01-01
We examine both one-dimensional and two-dimensional nonlinear resonance islands created in the transverse phase space of a proton synchrotron by nonlinear magnets. We also examine application of the theoretical framework constructed to the phenomenon of modulational diffusion in a collider model of the Fermilab Tevatron. For the one-dimensional resonance island system, we examine the effects of two types of modulational perturbations on the stability of these resonance islands: tune modulation and beta function modulation. Hamiltonian models are presented which predict stability boundaries that depend on only three paramders: the strength and frequency of the modulation and the frequency of small oscillations inside the resonance island. These. models are compared to particle tracking with excellent agreement. The tune modulation model is also successfully tested in experiment, where frequency domain analysis coupled with tune modulation is demonstrated to be useful in measuring the strength of a nonlinear resonance. Nonlinear resonance islands are also examined in two transverse dimensions in the presence of coupling and linearly independent crossing resonances. We present a first-order Hamiltonian model which predicts fixed point locations, but does not reproduce small oscillation frequencies seen in tracking; therefore in this circumstance such a model is inadequate. Particle tracking is presented which shows evidence of two-dimensional persistent signals, and we make suggestions on methods for observing such signals in future experiment.
Easy fabrication of a tunable high-pass birdcage resonator.
Xu, Y; Tang, P
1997-07-01
A practical design for a high-pass birdcage resonator is presented. Precision seamless telescoping tubes were used for easy tuning of resonant frequency by adjusting the length of the coils. Three probes, of 4.4, 5.0, and 25.0 cm in diameter, respectively, were constructed and tested. An empirical formula is given that can be used to calculate the capacitance needed for a given frequency when the desired physical dimension and the number of elements of the coll are specified. A simple three-step procedure is suggested for easy fabrication of resonators that are routinely tunable over tens of megahertz.
A resonant chain of four transiting, sub-Neptune planets.
Mills, Sean M; Fabrycky, Daniel C; Migaszewski, Cezary; Ford, Eric B; Petigura, Erik; Isaacson, Howard
2016-05-26
Surveys have revealed many multi-planet systems containing super-Earths and Neptunes in orbits of a few days to a few months. There is debate whether in situ assembly or inward migration is the dominant mechanism of the formation of such planetary systems. Simulations suggest that migration creates tightly packed systems with planets whose orbital periods may be expressed as ratios of small integers (resonances), often in a many-planet series (chain). In the hundreds of multi-planet systems of sub-Neptunes, more planet pairs are observed near resonances than would generally be expected, but no individual system has hitherto been identified that must have been formed by migration. Proximity to resonance enables the detection of planets perturbing each other. Here we report transit timing variations of the four planets in the Kepler-223 system, model these variations as resonant-angle librations, and compute the long-term stability of the resonant chain. The architecture of Kepler-223 is too finely tuned to have been formed by scattering, and our numerical simulations demonstrate that its properties are natural outcomes of the migration hypothesis. Similar systems could be destabilized by any of several mechanisms, contributing to the observed orbital-period distribution, where many planets are not in resonances. Planetesimal interactions in particular are thought to be responsible for establishing the current orbits of the four giant planets in the Solar System by disrupting a theoretical initial resonant chain similar to that observed in Kepler-223.
Proton magnetic resonance spectroscopy of a gray matter heterotopia.
Marsh, L; Lim, K O; Sullivan, E V; Lane, B; Spielman, D
1996-12-01
We used proton magnetic resonance spectroscopy to examine resonances representing metabolites containing N-acetyl (NA) groups (predominantly N-acetyl aspartate), choline, and creatine within a large left-hemispheric gray matter heterotopia (GMH) in a 35-year-old man with corpus callosum agenesis. In contrast to normal brain tissue, including gray matter regions, heterotopic gray matter was characterized by relatively increased choline and creatine resonances and a normal NA signal. These data suggest increased cellular activity or persistent immature neuronal tissue in GMH relative to unaffected tissue.
Quasilocalization of gravity on a brane by resonant modes.
Csáki, C; Erlich, J; Hollowood, T J
2000-06-26
We examine the behavior of gravity in brane theories with extra dimensions in a nonfactorizable background geometry. We find that for metrics which are asymptotically flat far from the brane there is a resonant graviton mode at zero energy. The presence of this resonance ensures quasilocalization of gravity, whereby at intermediate scales the gravitational laws on the brane are approximately four dimensional. However, for scales larger than the lifetime of the graviton resonance the five-dimensional laws of gravity will be reproduced due to the decay of the four-dimensional graviton. We also give a simple classification of effective gravity theories for general background geometries.
Controller for Driving a Piezoelectric Actuator at Resonance
NASA Technical Reports Server (NTRS)
Aldrich, Jack; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Bao, Xiaoqi; Chang, Zensheu
2008-01-01
A digital control system based partly on an extremum-seeking control algorithm tracks the changing resonance frequency of a piezoelectric actuator or an electrically similar electromechanical device that is driven by a sinusoidal excitation signal and is required to be maintained at or near resonance in the presence of uncertain, changing external loads and disturbances. Somewhat more specifically, on the basis of measurements of the performance of the actuator, this system repeatedly estimates the resonance frequency and alters the excitation frequency as needed to keep it at or near the resonance frequency. In the original application for which this controller was developed, the piezoelectric actuator is part of an ultrasonic/sonic drill/corer. Going beyond this application, the underlying principles of design and operation are generally applicable to tracking changing resonance frequencies of heavily perturbed harmonic oscillators. Resonance-frequency-tracking analog electronic circuits are commercially available, but are not adequate for the present purpose for several reasons: The input/output characteristics of analog circuits tend to drift, often necessitating recalibration, especially whenever the same controller is used in driving a different resonator. In the case of an actuator in a system that has multiple modes characterized by different resonance frequencies, an analog controller can tune erroneously to one of the higher-frequency modes. The lack of programmability of analog controllers is problematic when faults occur, and is especially problematic for preventing tuning to a higher-frequency mode. In contrast, a digital controller can be programmed to restrict itself to a specified frequency range and to maintain stability even when the affected resonator is driven at high power and subjected to uncertain disturbances and variable loads. The present digital control system (see figure) is implemented by means of an algorithm that comprises three main
Sensitivity improvements of a resonance-based tactile sensor.
Murayama, Yoshinobu; Lindahl, Olof A
2017-02-01
Resonance-based contact-impedance measurement refers to the application of resonance sensors based on the measurement of the changes in the resonance curve of an ultrasonic resonator in contact with a surface. The advantage of the resonance sensor is that it is very sensitive to small changes in the contact impedance. A sensitive micro tactile sensor (MTS) was developed, which measured the elasticity of soft living tissues at the single-cell level. In the present paper, we studied the method of improving the touch and stiffness sensitivity of the MTS. First, the dependence of touch sensitivity in relation to the resonator length was studied by calculating the sensitivity coefficient at each length ranging from 9 to 40 mm. The highest touch sensitivity was obtained with a 30-mm-long glass needle driven at a resonance frequency of 100 kHz. Next, the numerical calculation of contact impedance showed that the highest stiffness sensitivity was achieved when the driving frequency was 100 kHz and the contact-tip diameter of the MTS was 10 μm. The theoretical model was then confirmed experimentally using a phase-locked-loop-based digital feedback oscillation circuit. It was found that the developed MTS, whose resonant frequency was 97.030 kHz, performed with the highest sensitivity of 53.2 × 10(6) Hz/N at the driving frequency of 97.986 kHz, i.e. the highest sensitivity was achieved at 956 Hz above the resonant frequency.
Simulation of pyroshock environments using a tunable resonant fixture
Davie, N.T.
1993-09-30
Disclosed are a method and apparatus for simulating pyrotechnic shock for the purpose of qualifying electronic components for use in weapons, satellite, and aerospace applications. According to the invention, a single resonant bar fixture has an adjustable resonant frequency in order to exhibit a desired shock response spectrum upon mechanical impact. The invention eliminates the need for availability of a large number of different fixtures, capable of exhibiting a range of shock response characteristics, in favor of a single tunable system.
Simulation of pyroshock environments using a tunable resonant fixture
Davie, N.T.
1996-10-15
Disclosed are a method and apparatus for simulating pyrotechnic shock for the purpose of qualifying electronic components for use in weapons, satellite, and aerospace applications. According to the invention, a single resonant bar fixture has an adjustable resonant frequency in order to exhibit a desired shock response spectrum upon mechanical impact. The invention eliminates the need for availability of a large number of different fixtures, capable of exhibiting a range of shock response characteristics, in favor of a single tunable system. 32 figs.
Simulation of pyroshock environments using a tunable resonant fixture
Davie, Neil T.
1996-01-01
Disclosed are a method and apparatus for simulating pyrotechnic shock for the purpose of qualifying electronic components for use in weapons, satellite, and aerospace applications. According to the invention, a single resonant bar fixture has an adjustable resonant frequency in order to exhibit a desired shock response spectrum upon mechanical impact. The invention eliminates the need for availability of a large number of different fixtures, capable of exhibiting a range of shock response characteristics, in favor of a single tunable system.
A study of the main resonances outside the geostationary ring
NASA Astrophysics Data System (ADS)
Celletti, Alessandra; Galeş, Cătălin
2015-08-01
We investigate the dynamics of satellites and space debris in external resonances, namely in the region outside the geostationary ring. Precisely, we focus on the 1:2, 1:3, 2:3 resonances, which are located at about 66 931.4 km, 87 705.0 km, 55 250.7 km, respectively. Some of these resonances have been already exploited in space missions, like XMM-Newton and Integral. Our study is mainly based on a Hamiltonian approach, which allows us to get fast and reliable information on the dynamics in the resonant regions. Significative results are obtained even by considering just the effect of the geopotential in the Hamiltonian formulation. For objects (typically space debris) with high area-to-mass ratio the Hamiltonian includes also the effect of the solar radiation pressure. In addition, we perform a comparison with the numerical integration in Cartesian variables, including the geopotential, the gravitational attraction of Sun and Moon, and the solar radiation pressure. We implement some simple mathematical tools that allows us to get information on the terms which are dominant in the Fourier series expansion of the Hamiltonian around a given resonance, on the amplitude of the resonant islands and on the location of the equilibrium points. We also compute the Fast Lyapunov Indicators, which provide a cartography of the resonant regions, yielding the main dynamical features associated to the external resonances. We apply these techniques to analyze the 1:2, 1:3, 2:3 resonances; we consider also the case of objects with large area-to-mass ratio and we provide an application to the case studies given by XMM-Newton and Integral.
Broadband converging plasmon resonance at a conical nanotip.
Wang, Yunshan; Plouraboue, Franck; Chang, Hsueh-Chia
2013-03-11
We propose an analytical theory which predicts that Converging Plasmon Resonance (CPR) at conical nanotips exhibits a red-shifted and continuous band of resonant frequencies and suggests potential application of conical nanotips in various fields, such as plasmonic solar cells, photothermal therapy, tip-enhanced Raman and other spectroscopies. The CPR modes exhibit superior confinement and ten times broader scattering bandwidth over the entire solar spectrum than smooth nano-structures. The theory also explicitly connects the optimal angles and resonant optical frequencies to the material permittivities, with a specific optimum half angle that depends only on the real permittivity for high-permittivity and low-loss materials.
Double Resonance Inversion Recovery in a Heteronuclear Two Spin System
NASA Astrophysics Data System (ADS)
Ishiwata, Mitsumasa; Koizumi, Jun-ichi
1988-09-01
For a heteronuclear coupled AX spin system, recovery after inversion of the A spin lines in A-\\{X\\} double resonance spectra is observed under a spin tickling condition. Oscillations in the A lines after inversion are found to decay more rapidly than expected and depend on inhomogeneity of an applied static field. After the initial oscillating stage, the recovery of the tickling spectra can considerably be accelerated by an irradiation field which is applied near a resonance of an X line. A simple mathematical method is presented for calculating the double resonance recovery process under the inhomogeneity of the static field. Such an inhomogeneity modifies a recovery time near the resonance. Experimental results for 13C-enriched formic acid are reproduced by numerical computation. Acceleration of the recovery is explained in terms of a saturation effect of the irradiated line.
Control of critical coupling in a coiled coaxial cable resonator
NASA Astrophysics Data System (ADS)
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.
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.
Resonant processes in atomic collisions and a unified view
NASA Astrophysics Data System (ADS)
Hahn, Yukap
1990-06-01
Resonant states of ions are copiously produced in violent electron-ion and ion-atom collisions when inner-shell electrons are excited or excitation of the ion is followed by electron capture. Various resonant processes are inter-related by unitarity, analyticity and impulse approximation, so that their cross section data can be correlated. The recent progress made in dielectronic recombination and transfer-excitation is discussed. A resonance model for the pair line production in heavy ion collisions is examined and the predicted spectrum is presented.
A random dynamical systems perspective on stochastic resonance
NASA Astrophysics Data System (ADS)
Cherubini, Anna Maria; Lamb, Jeroen S. W.; Rasmussen, Martin; Sato, Yuzuru
2017-07-01
We study stochastic resonance in an over-damped approximation of the stochastic Duffing oscillator from a random dynamical systems point of view. We analyse this problem in the general framework of random dynamical systems with a nonautonomous forcing. We prove the existence of a unique global attracting random periodic orbit and a stationary periodic measure. We use the stationary periodic measure to define an indicator for the stochastic resonance.
Fermi resonance in dynamical tunneling in a chaotic billiard.
Yi, Chang-Hwan; Kim, Ji-Hwan; Yu, Hyeon-Hye; Lee, Ji-Won; Kim, Chil-Min
2015-08-01
We elucidate that Fermi resonance ever plays a decisive role in dynamical tunneling in a chaotic billiard. Interacting with each other through an avoided crossing, a pair of eigenfunctions are coupled through tunneling channels for dynamical tunneling. In this case, the tunneling channels are an islands chain and its pair unstable periodic orbit, which equals the quantum number difference of the eigenfunctions. This phenomenon of dynamical tunneling is confirmed in a quadrupole billiard in relation with Fermi resonance.
Analysis of a Precambrian resonance-stabilized day length
NASA Astrophysics Data System (ADS)
Bartlett, Benjamin C.; Stevenson, David J.
2016-06-01
During the Precambrian era, Earth's decelerating rotation would have passed a 21 h period that would have been resonant with the semidiurnal atmospheric thermal tide. Near this point, the atmospheric torque would have been maximized, being comparable in magnitude but opposite in direction to the lunar torque, halting Earth's rotational deceleration, maintaining a constant day length, as detailed by Zahnle and Walker (1987). We develop a computational model to determine necessary conditions for formation and breakage of this resonant effect. Our simulations show the resonance to be resilient to atmospheric thermal noise but suggest a sudden atmospheric temperature increase like the deglaciation period following a possible "snowball Earth" near the end of the Precambrian would break this resonance; the Marinoan and Sturtian glaciations seem the most likely candidates for this event. Our model provides a simulated day length over time that resembles existing paleorotational data, though further data are needed to verify this hypothesis.
Optical resonance problem in metamaterial arrays: a lattice dynamics approach
NASA Astrophysics Data System (ADS)
Liu, Wanguo
2016-11-01
A systematic dynamic theory is established to deal with the optical collective resonance in metamaterial arrays. As a reference model, we consider an infinite split ring resonator (SRR) array illuminated by a linearly polarized wave and introduce an N-degree-of-freedom forced oscillator equation to simplify the coupled-mode vibration problem. We derive a strict formula of resonance frequency (RF) and its adjustable range from the steady-state response. Unlike a single SRR possesses invariant RF, it successfully explains the mechanism of RF shift effect in the SRR array when the incident angle changes. Instead of full wave analysis, only one or two adjacent resonance modes can give an accurate response line shape. Our approach is applicable for metallic arrays with any N-particle cell at all incident angles and well matched with numerical results. It provides a versatile way to study the vibration dynamics in optical periodic many-body systems.
Experiment study of an electron cyclotron resonant ion source based on a tapered resonance cavity
Yang, Juan; Shi, Feng; Jin, Yizhou; Wang, Yunmin; Komurasaki, Kimiya
2013-12-15
Electron cyclotron resonant plasma is one type of magnetised plasma generated by continuous microwave energy. It has the property of high degree of ionization and large volume at low gas pressure, which makes it useful for space propulsion and material processing. This article presents the experiment study of the plasma properties and ion beam extraction from an electron cyclotron resonant ion source based on a tapered resonance cavity. Optical emission spectroscopy based on a simple collisional radiation model was used for plasma diagnosis. Experiment results show that, at microwave power setting ranging from 7.06 to 17.40 W and mass flow rate ranging from 1 to 10 sccm, argon gas can be ionized. Ion beam of 109.1 mA from the ion source can be extracted at microwave power of 30 W, mass flow rate of 10 sccm, and accel voltage of 800 V. The diagnosed plasma temperature and density are 2.4–5.2 eV and 2 × 10{sup 16}–4.8 × 10{sup 17} m{sup −3}, respectively.
Single-electron Spin Resonance in a Quadruple Quantum Dot.
Otsuka, Tomohiro; Nakajima, Takashi; Delbecq, Matthieu R; Amaha, Shinichi; Yoneda, Jun; Takeda, Kenta; Allison, Giles; Ito, Takumi; Sugawara, Retsu; Noiri, Akito; Ludwig, Arne; Wieck, Andreas D; Tarucha, Seigo
2016-08-23
Electron spins in semiconductor quantum dots are good candidates of quantum bits for quantum information processing. Basic operations of the qubit have been realized in recent years: initialization, manipulation of single spins, two qubit entanglement operations, and readout. Now it becomes crucial to demonstrate scalability of this architecture by conducting spin operations on a scaled up system. Here, we demonstrate single-electron spin resonance in a quadruple quantum dot. A few-electron quadruple quantum dot is formed within a magnetic field gradient created by a micro-magnet. We oscillate the wave functions of the electrons in the quantum dots by applying microwave voltages and this induces electron spin resonance. The resonance energies of the four quantum dots are slightly different because of the stray field created by the micro-magnet and therefore frequency-resolved addressable control of each electron spin resonance is possible.
Single-electron Spin Resonance in a Quadruple Quantum Dot
NASA Astrophysics Data System (ADS)
Otsuka, Tomohiro; Nakajima, Takashi; Delbecq, Matthieu R.; Amaha, Shinichi; Yoneda, Jun; Takeda, Kenta; Allison, Giles; Ito, Takumi; Sugawara, Retsu; Noiri, Akito; Ludwig, Arne; Wieck, Andreas D.; Tarucha, Seigo
2016-08-01
Electron spins in semiconductor quantum dots are good candidates of quantum bits for quantum information processing. Basic operations of the qubit have been realized in recent years: initialization, manipulation of single spins, two qubit entanglement operations, and readout. Now it becomes crucial to demonstrate scalability of this architecture by conducting spin operations on a scaled up system. Here, we demonstrate single-electron spin resonance in a quadruple quantum dot. A few-electron quadruple quantum dot is formed within a magnetic field gradient created by a micro-magnet. We oscillate the wave functions of the electrons in the quantum dots by applying microwave voltages and this induces electron spin resonance. The resonance energies of the four quantum dots are slightly different because of the stray field created by the micro-magnet and therefore frequency-resolved addressable control of each electron spin resonance is possible.
Single-electron Spin Resonance in a Quadruple Quantum Dot
Otsuka, Tomohiro; Nakajima, Takashi; Delbecq, Matthieu R.; Amaha, Shinichi; Yoneda, Jun; Takeda, Kenta; Allison, Giles; Ito, Takumi; Sugawara, Retsu; Noiri, Akito; Ludwig, Arne; Wieck, Andreas D.; Tarucha, Seigo
2016-01-01
Electron spins in semiconductor quantum dots are good candidates of quantum bits for quantum information processing. Basic operations of the qubit have been realized in recent years: initialization, manipulation of single spins, two qubit entanglement operations, and readout. Now it becomes crucial to demonstrate scalability of this architecture by conducting spin operations on a scaled up system. Here, we demonstrate single-electron spin resonance in a quadruple quantum dot. A few-electron quadruple quantum dot is formed within a magnetic field gradient created by a micro-magnet. We oscillate the wave functions of the electrons in the quantum dots by applying microwave voltages and this induces electron spin resonance. The resonance energies of the four quantum dots are slightly different because of the stray field created by the micro-magnet and therefore frequency-resolved addressable control of each electron spin resonance is possible. PMID:27550534
Exploitation of resonance Raman spectroscopy as a remote chemical sensor
Sedlacek, A.J.; Chen, C.L.
1995-08-01
We have discussed recent experimental results using a resonance-Raman-based LIDAR system as a remote chemical sensor. This spectroscopy has the fundamental advantage that it is based on optical fingerprints that are insensitive to environmental perturbations. By taking advantage of resonance enhancement, which 6 orders-of-magnitude, can be as large as 4 to an increased sensing range for a given chemical concentration or lower detection limit for a given stand-off distance can be realized. The success discussed above can in part be traced back to the use of new state-of-the-art technologies which, only recently, have allowed the phenomenon of resonance-enhanced Raman spectroscopy to be fully exploited as a remote chemical sensor platform. Since many chemicals have electronic transitions in the UV/IS, it is expected that many will have pronounced resonance enhancements.
Resonator-assisted quantum bath engineering of a flux qubit
NASA Astrophysics Data System (ADS)
Zhang, Xian-Peng; Shen, Li-Tuo; Yin, Zhang-Qi; Wu, Huai-Zhi; Yang, Zhen-Biao
2015-01-01
We demonstrate quantum bath engineering for preparation of any orbital state with the controllable phase factor of a superconducting flux qubit assisted by a microwave coplanar waveguide resonator. We investigate the polarization efficiency of the arbitrary direction rotating on the Bloch sphere, and obtain an effective Rabi frequency by using the convergence condition of the Markovian master equation. The processes of polarization can be implemented effectively in a dissipative environment created by resonator photon loss when the spectrum of the microwave resonator matches with the specially tailored Rabi and resonant frequencies of the drive. Our calculations indicate that state-preparation fidelities in excess of 99% and the required time on the order of magnitude of a microsecond are in principle possible for experimentally reasonable sample parameters. Furthermore, our proposal could be applied to other systems with spin-based qubits.
Magnetic Resonance Fiber Tracking in a Neonate with Hemimegalencephaly
Re, Thomas J; Scarciolla, Laura; Takahashi, Emi; Specchio, Nicola; Bernardi, Bruno; Longo, Daniela
2015-01-01
A magnetic resonance diffusion fiber tracking study in neonate diagnosed with left hemisphere hemimegalencephaly is presented. Despite diffuse morphologic deformities identified in conventional imaging, all major pathways were identifiable bilaterally with minor aberrations in vicinity of morphologic lesions. PMID:25655045
Plasma resonances in a microwave-driven microdischarge
Xue, J.; Urdahl, R. S.; Cooley, J. E.
2012-02-06
This work investigates resonances in a capacitively coupled, low pressure krypton microdischarge operated at 2.5 GHz. A circuit model for the device, which has a length dimension of approximately 1 mm, calculates impedance values for a range of electron densities. The model results predict several 'parallel' and 'series' resonances at the driving frequency when the electron density is approximately 8 x 10{sup 11} cm{sup -3} and 5 x 10{sup 12} cm{sup -3}. The series resonance occurs when the resistance approaches the output impedance of the radio-frequency signal source, minimizing the reflected power. These resonances explain an experimentally observed jump in intensity with increasing input power.
Free-vibration acoustic resonance of a nonlinear elastic bar
NASA Astrophysics Data System (ADS)
Tarumi, Ryuichi; Oshita, Yoshihito
2011-02-01
Free-vibration acoustic resonance of a one-dimensional nonlinear elastic bar was investigated by direct analysis in the calculus of variations. The Lagrangian density of the bar includes a cubic term of the deformation gradient, which is responsible for both geometric and constitutive nonlinearities. By expanding the deformation function into a complex Fourier series, we derived the action integral in an analytic form and evaluated its stationary conditions numerically with the Ritz method for the first three resonant vibration modes. This revealed that the bar shows the following prominent nonlinear features: (i) amplitude dependence of the resonance frequency; (ii) symmetry breaking in the vibration pattern; and (iii) excitation of the high-frequency mode around nodal-like points. Stability of the resonant vibrations was also addressed in terms of a convex condition on the strain energy density.
Resonance Frequency Readout Circuit for a 900 MHz SAW Device.
Liu, Heng; Zhang, Chun; Weng, Zhaoyang; Guo, Yanshu; Wang, Zhihua
2017-09-15
A monolithic resonance frequency readout circuit with high resolution and short measurement time is presented for a 900 MHz RF surface acoustic wave (SAW) sensor. The readout circuit is composed of a fractional-N phase-locked loop (PLL) as the stimulus source to the SAW device and a phase-based resonance frequency detecting circuit using successive approximation (SAR). A new resonance frequency searching strategy has been proposed based on the fact that the SAW device phase-frequency response crosses zero monotonically around the resonance frequency. A dedicated instant phase difference detecting circuit is adopted to facilitate the fast SAR operation for resonance frequency searching. The readout circuit has been implemented in 180 nm CMOS technology with a core area of 3.24 mm². In the experiment, it works with a 900 MHz SAW resonator with a quality factor of Q = 130. Experimental results show that the readout circuit consumes 7 mW power from 1.6 V supply. The frequency resolution is 733 Hz, and the relative accuracy is 0.82 ppm, and it takes 0.48 ms to complete one measurement. Compared to the previous results in the literature, this work has achieved the shortest measurement time with a trade-off between measurement accuracy and measurement time.
Resonance Frequency Readout Circuit for a 900 MHz SAW Device
Liu, Heng; Zhang, Chun; Weng, Zhaoyang; Guo, Yanshu; Wang, Zhihua
2017-01-01
A monolithic resonance frequency readout circuit with high resolution and short measurement time is presented for a 900 MHz RF surface acoustic wave (SAW) sensor. The readout circuit is composed of a fractional-N phase-locked loop (PLL) as the stimulus source to the SAW device and a phase-based resonance frequency detecting circuit using successive approximation (SAR). A new resonance frequency searching strategy has been proposed based on the fact that the SAW device phase-frequency response crosses zero monotonically around the resonance frequency. A dedicated instant phase difference detecting circuit is adopted to facilitate the fast SAR operation for resonance frequency searching. The readout circuit has been implemented in 180 nm CMOS technology with a core area of 3.24 mm2. In the experiment, it works with a 900 MHz SAW resonator with a quality factor of Q = 130. Experimental results show that the readout circuit consumes 7 mW power from 1.6 V supply. The frequency resolution is 733 Hz, and the relative accuracy is 0.82 ppm, and it takes 0.48 ms to complete one measurement. Compared to the previous results in the literature, this work has achieved the shortest measurement time with a trade-off between measurement accuracy and measurement time. PMID:28914799
Resonant Phase Patterns in a Reaction-Diffusion System
Lin, Anna L.; Bertram, Matthias; Martinez, Karl; Swinney, Harry L.; Ardelea, Alexandre; Carey, Graham F.
2000-05-01
Resonance regions similar to the Arnol'd tongues found in single oscillator frequency locking are observed in experiments using a spatially extended periodically forced Belousov-Zhabotinsky system. We identify six distinct 2:1 subharmonic resonant patterns and describe them in terms of the position-dependent phase and magnitude of the oscillations. Some experimentally observed features are also found in numerical studies of a forced Brusselator reaction-diffusion model. (c) 2000 The American Physical Society.
A Model of Bone Remodelling Based on Stochastic Resonance
NASA Astrophysics Data System (ADS)
Rusconi, M.; Zaikin, A.; Marwan, N.; Kurths, J.
2008-06-01
One of the most crucial medical challenges for long-term space flights is the prevention of bone loss affecting astronauts and its dramatic consequences on their return to gravitational field. Recently, a new noise-induced phenomenon in bone formation has been reported experimentally [1]. With this contribution we propose a model for this findings based on Stochastic Resonance [2]. Our simulations suggest new countermeasures for bone degeneration during long space fights using the effect of Stochastic Resonance.
A microprocessor-based multichannel subsensory stochastic resonance electrical stimulator.
Chang, Gwo-Ching
2013-01-01
Stochastic resonance electrical stimulation is a novel intervention which provides potential benefits for improving postural control ability in the elderly, those with diabetic neuropathy, and stroke patients. In this paper, a microprocessor-based subsensory white noise electrical stimulator for the applications of stochastic resonance stimulation is developed. The proposed stimulator provides four independent programmable stimulation channels with constant-current output, possesses linear voltage-to-current relationship, and has two types of stimulation modes, pulse amplitude and width modulation.
Theory of a resonance oscillator with relay interaction
NASA Astrophysics Data System (ADS)
Alekseev, G. A.; Mikhailov, V. I.; Pivovarova, A. G.
A theoretical analysis is presented of an open-resonator oscillator the operation of which is based on the relay interaction of a broad ribbon-shaped electron beam with the spatial harmonic of the HF field of the resonator. Relations of the general theory of oscillator excitation are used to investigate the dependence of the output characteristics on the parameters of the problem, assuming the distribution of HF amplitude to be uniform along the periodic structure.
A point about electron paramagnetic resonance detection of irradiated foodstuffs
NASA Astrophysics Data System (ADS)
Douifi, Leila; Raffi, Jacques; Stocker, Pierre; Dole, François
1998-12-01
This paper makes a point about the identification of irradiated foodstuffs by means of electron paramagnetic resonance (EPR) or electron spin resonance (ESR). EPR is the most accurate method for such routine applications since radicals are stabilised for a long time in all (or part of) foods that are in solid and dry states; consequently, EPR can be applied to meat and fish bones, fruit and relative products (from vegetal origin). More details are given for mollusc shells, such as oysters and mussels.
Boosting the power factor with resonant states: A model study
NASA Astrophysics Data System (ADS)
Thébaud, S.; Adessi, Ch.; Pailhès, S.; Bouzerar, G.
2017-08-01
A particularly promising pathway to enhance the efficiency of thermoelectric materials lies in the use of resonant states, as suggested by experimentalists and theorists alike. In this paper, we go over the mechanisms used in the literature to explain how resonant levels affect the thermoelectric properties, and we suggest that the effects of hybridization are crucial yet ill understood. In order to get a good grasp of the physical picture and to draw guidelines for thermoelectric enhancement, we use a tight-binding model containing a conduction band hybridized with a flat band. We find that the conductivity is suppressed in a wide energy range near the resonance, but that the Seebeck coefficient can be boosted for strong enough hybridization, thus allowing for a significant increase of the power factor. The Seebeck coefficient can also display a sign change as the Fermi level crosses the resonance. Our results suggest that in order to boost the power factor, the hybridization strength must not be too low, the resonant level must not be too close to the conduction (or valence) band edge, and the Fermi level must be located around, but not inside, the resonant peak.
Pluto and Charon: A Case of Precession-Orbit Resonance?
NASA Technical Reports Server (NTRS)
Rubincam, David Parry; Smith, David E. (Technical Monitor)
2000-01-01
Pluto may be the only known case of precession-orbit resonance in the solar system. The Pluto-Charon system orbits the Sun with a period of 1 Plutonian year, which is 250.8 Earth years. The observed parameters of the system are such that Charon may cause Pluto to precess with a period near 250.8 Earth years. This gives rise to two possible resonances, heretofore unrecognized. The first is due to Pluto's orbit being highly eccentric, giving solar torques on Charon with a period of 1 Plutonian year. Charon in turn drives Pluto near its precession period. Volatiles, which are expected to shuttle across Pluto's surface between equator and pole as Pluto's obliquity oscillates, might change the planet's dynamical flattening enough so that Pluto crosses the nearby resonance, forcing the planet's equatorial plane to depart from Charon's orbital plane. The mutual tilt can reach as much as 2 deg after integrating over 5.6 x 10(exp 6) years, depending upon how close Pluto is to the resonance and the supply of volatiles. The second resonance is due to the Sun's traveling above and below Charon's orbital plane; it has a period half that of the eccentricity resonance. Reaching this half-Plutonian year resonance requires a much larger but still theoretically possible amount of volatiles. In this case the departure of Charon from an equatorial orbit is about 1 deg after integrating for 5.6 x 10(exp 6) years. The calculations ignore libration and tidal friction. It is not presently known how large the mutual tilt can grow over the age of the solar system, but if it remains only a few degrees, then observing such small angles from a Pluto flyby mission would be difficult. It is not clear why the parameters of the Pluto-Charon system are so close to the eccentricity resonance.
Signal amplification in a qubit-resonator system
NASA Astrophysics Data System (ADS)
Karpov, D. S.; Oelsner, G.; Shevchenko, S. N.; Greenberg, Ya. S.; Il'ichev, E.
2016-03-01
We study the dynamics of a qubit-resonator system, when the resonator is driven by two signals. The interaction of the qubit with the high-amplitude driving we consider in terms of the qubit dressed states. Interaction of the dressed qubit with the second probing signal can essentially change the amplitude of this signal. We calculate the transmission amplitude of the probe signal through the resonator as a function of the qubit's energy and the driving frequency detuning. The regions of increase and attenuation of the transmitted signal are calculated and demonstrated graphically. We present the influence of the signal parameters on the value of the amplification, and discuss the values of the qubit-resonator system parameters for an optimal amplification and attenuation of the weak probe signal.
A wavelength demultiplexing structure based on graphene nanoribbon resonators
NASA Astrophysics Data System (ADS)
Zhuang, Huawei; Sheng, Shiwei; Kong, Fanmin; Li, Kang; Wang, Yuling
2016-12-01
A wavelength demultiplexing (WDM) structure based on graphene nanoribbon resonators is proposed and numerically investigated by the finite-difference time-domain (FDTD) method. The demultiplexing wavelength can be easily derived by adjusting the length of the resonator, which is accurately explained by the Fabry-Perot (F-P) resonant theory. Meanwhile, the transmission characteristics of the WDM structure are influenced by the coupling distance between the resonator and drop/bus waveguides, and the performance of the WDM device is analyzed at different nanoribbon width and chemical potential. In addition, in order to improve the transmission efficiency from the drop waveguide, a reflection structure is introduced at the end of the bus waveguide. The exact mechanism for the WDM structure is analyzed in detail using the temporal coupled-mode theory. The proposed structure will have potential applications in the field of ultra-compact WDM systems in highly integrated optical circuits.
NASA Astrophysics Data System (ADS)
Xiong, Wei; Jin, Da-Yu; Jing, Jun; Lam, Chi-Hang; You, J. Q.
2015-09-01
We study a tripartite quantum system consisting of a coplanar-waveguide (CPW) resonator and a nanomechanical resonator (NAMR) connected by a flux qubit, where the flux qubit has a large detuning from both resonators. By a unitary transformation and a second-order approximation, we obtain a strong and controllable (i.e., magnetic-field-dependent) effective coupling between the NAMR and the CPW resonator. Due to the strong coupling, vacuum Rabi splitting can be observed from the voltage-fluctuation spectrum of the CPW resonator. We further study the properties of single-photon transport as inferred from the reflectance or equivalently the transmittance. We show that the reflectance and the corresponding phase-shift spectra both exhibit doublet of narrow spectral features due to vacuum Rabi splitting. By tuning the external magnetic field, the reflectance and the phase shift can be varied from 0 to 1 and -π to π , respectively. The results indicate that this hybrid quantum system can act as a quantum router.
Resonantly Enhanced Emission from a Luminescent Nanostructured Waveguide
NASA Astrophysics Data System (ADS)
Inada, Yasuhisa; Hashiya, Akira; Nitta, Mitsuru; Tomita, Shogo; Tsujimoto, Akira; Suzuki, Masa-Aki; Yamaki, Takeyuki; Hirasawa, Taku
2016-09-01
Controlling the characteristics of photon emission represents a significant challenge for both fundamental science and device technologies. Research on microcavities, photonic crystals, and plasmonic nanocavities has focused on controlling spontaneous emission by way of designing a resonant structure around the emitter to modify the local density of photonic states. In this work, we demonstrate resonantly enhanced emission using luminescent nanostructured waveguide resonance (LUNAR). Our concept is based on coupling between emitters in the luminescent waveguide and a resonant waveguide mode that interacts with a periodic nanostructure and hence outcouples via diffraction. We show that the enhancement of resonance emission can be controlled by tuning the design parameters. We also demonstrate that the enhanced emission is attributable to the accelerated spontaneous emission rate that increases the probability of photon emission in the resonant mode, accompanied by enhanced the local density of photonic states. This study demonstrates that nanostructured luminescent materials can be designed to exhibit functional and enhanced emission. We anticipate that our concept will be used to improve the performance of a variety of photonic and optical applications ranging from bio/chemical sensors to lighting, displays and projectors.
Resonance in a weakly nonlinear system with slowly varying parameters
NASA Astrophysics Data System (ADS)
Kevorkian, J.
1980-02-01
Multiple-variable expansion procedures appropriate for nonlinear systems in resonance are surveyed by the use of the model of two coupled weakly nonlinear oscillators with either constant or slowly varying frequencies. In the autonomous problem it is shown that an n-variable expansion (where n depends on the order of accuracy desired) yields uniformly valid results. The problem of passage through resonance for the nonautonomous problem is also considered and the solution is described by constructing a sequence of three expansions. The solution before resonance is developed as a generalized multiple-variable expansion and is matched with an inner expansion valid during resonance. This latter is then matched with a postresonance solution and determines it completely. Numerical integrations are used to substantiate the theoretical results. The dominant effect of passage through resonance is shown to be the excitation of a higher-order oscillation beyond resonance. Contrary to the claim in a recent work, the total action of the system does not remain constant if one accounts for the leading perturbation terms in the postresonance solution. Instead, the total action goes from one constant value to another.
Optimized pulse shapes for a resonator-induced phase gate
NASA Astrophysics Data System (ADS)
Cross, Andrew W.; Gambetta, Jay M.
2015-03-01
The resonator-induced phase gate is a multiqubit controlled-phase gate for fixed-frequency superconducting qubits. Through off-resonant driving of a bus resonator, statically coupled qubits acquire a state-dependent phase. However, photon loss leads to dephasing during the gate, and any residual entanglement between the resonator and qubits after the gate leads to decoherence. Here we consider how to shape the drive pulse to minimize these unwanted effects. First, we review how the gate's entangling and dephasing rates depend on the system parameters and validate closed-form solutions against direct numerical solution of a master equation. Next, we propose spline pulse shapes that reduce residual qubit-bus entanglement, are robust to imprecise knowledge of the resonator shift, and can be shortened by using higher-degree polynomials. Finally, we present a procedure that optimizes over the subspace of pulses that leave the resonator unpopulated. This finds shaped drive pulses that further reduce the gate duration. Assuming realistic parameters, we exhibit shaped pulses that have the potential to realize ˜212 ns spline pulse gates and ˜120 ns optimized gates with ˜6 ×10-4 average gate infidelity. These examples do not represent fundamental limits of the gate and, in principle, even shorter gates may be achievable.
Resonantly Enhanced Emission from a Luminescent Nanostructured Waveguide
Inada, Yasuhisa; Hashiya, Akira; Nitta, Mitsuru; Tomita, Shogo; Tsujimoto, Akira; Suzuki, Masa-aki; Yamaki, Takeyuki; Hirasawa, Taku
2016-01-01
Controlling the characteristics of photon emission represents a significant challenge for both fundamental science and device technologies. Research on microcavities, photonic crystals, and plasmonic nanocavities has focused on controlling spontaneous emission by way of designing a resonant structure around the emitter to modify the local density of photonic states. In this work, we demonstrate resonantly enhanced emission using luminescent nanostructured waveguide resonance (LUNAR). Our concept is based on coupling between emitters in the luminescent waveguide and a resonant waveguide mode that interacts with a periodic nanostructure and hence outcouples via diffraction. We show that the enhancement of resonance emission can be controlled by tuning the design parameters. We also demonstrate that the enhanced emission is attributable to the accelerated spontaneous emission rate that increases the probability of photon emission in the resonant mode, accompanied by enhanced the local density of photonic states. This study demonstrates that nanostructured luminescent materials can be designed to exhibit functional and enhanced emission. We anticipate that our concept will be used to improve the performance of a variety of photonic and optical applications ranging from bio/chemical sensors to lighting, displays and projectors. PMID:27682993
Approximation of fermion resonances on a splitting domain wall
NASA Astrophysics Data System (ADS)
Farokhtabar, A.; Tofighi, A.
2017-08-01
In this paper the splitting of a domain wall is investigated analytically in flat spacetime. We also study fermion localization and resonances on this domain wall. Masses of Kaluza-Klein modes determined by two methods, numerical method and approximation one. We observe that the agreement between approximated values and numeric ones is good. It is found that the number of fermion resonances on the brane is increased with mass parameter.
Parametric resonances and stochastic layer induced by a phase modulation
Liu, J.Y.; Ball, M.; Brabson, B.
1995-12-31
The Hamiltonian system with phase modulation in a higher harmonic rf cavity is experimentally studied on the IUCF cooler ring. The Poincare maps in the resonant rotating frame are obtained from experimental data and compared with numerical tracking. The formation of the stochastic layer due to the overlap of parametric resonances is discussed. The dependence of the stochastic layer on the voltage of the higher harmonic rf cavity, amplitude and frequency of the phase modulation is studied.
Atom loss resonances in a Bose-Einstein condensate.
Langmack, Christian; Smith, D Hudson; Braaten, Eric
2013-07-12
Atom loss resonances in ultracold trapped atoms have been observed at scattering lengths near atom-dimer resonances, at which Efimov trimers cross the atom-dimer threshold, and near two-dimer resonances, at which universal tetramers cross the dimer-dimer threshold. We propose a new mechanism for these loss resonances in a Bose-Einstein condensate of atoms. As the scattering length is ramped to the large final value at which the atom loss rate is measured, the time-dependent scattering length generates a small condensate of shallow dimers coherently from the atom condensate. The coexisting atom and dimer condensates can be described by a low-energy effective field theory with universal coefficients that are determined by matching exact results from few-body physics. The classical field equations for the atom and dimer condensates predict narrow enhancements in the atom loss rate near atom-dimer resonances and near two-dimer resonances due to inelastic dimer collisions.
Optics and biophotonics of nanoparticles with a plasmon resonance
Khlebtsov, N G
2008-06-30
A brief review of the state of the art in theoretical and experimental studies of the optical properties of metal particles with dipole and multipole plasmon resonances is presented. Metal spheres, nanorods, spherical and elliptic metal nanoshells are considered. The tuning of plasmon resonances of nanoparticles by varying their size, shape, structure, and dielectric environment is described. A large amount of spectrophotometric data on dimensional characteristics of gold colloidal particles is critically analysed and a new calibration of the dependence of their average size on the extinction plasmon resonance wavelength is proposed. A drastic difference between gold and silver colloids in the region of small deviations of their form from spherical is discussed. An example of the excess over not only the Rayleigh limit for the scattering depolarisation factor for dielectric needles (1/3) but also over the plasmon-resonance limit for metal thin rods (3/4) is presented for the first time. The multipole properties of nanorods and universal linear wavelength scaling of multipole resonances are considered depending on the axial ratio of nanoparticles. The outlook for modern trends in biomedical applications of nanoparticles with plasmon resonances is discussed. (special issue devoted to application of laser technologies in biophotonics and biomedical studies)
Localization of a continuum shape resonance - Photoionization of CS2
NASA Astrophysics Data System (ADS)
Kakar, Sandeep; Choi, Heung-Cheun; Poliakoff, E. D.
1992-10-01
We report a vibrationally resolved investigation into the 5sigma(u) exp -1 shape-resonant ionization dynamics for CS2 in the range h nu 18-30 eV. The intensity of dispersed fluorescence from CS2(+)(B 2Sigma(u)(+) photoions is measured to obtain partial photoionization cross-section curves for the v = (0,0,0) and (1,0,0) levels of CS2(+)(B 2Sigma(u)(+), as well as the vibrational branching ratio. Our results indicate a shape resonance at hv equal to about 21 eV which is insensitive to changes in the symmetric stretching coordinate. These data are consistent with recent theoretical efforts that predict a shape resonance in the 5sigma(u) - epsilon pi(g) channel. All previous vibrationally resolved data on shape resonances have been obtained for systems whose shape resonances occur in the (epsilon sigma) continuum. The current results are in contrast to behavior observed for other shape resonances, highlighting both their diverse nature and possible extensions of the current measurements.
A Resonant Pressure Microsensor Capable of Self-Temperature Compensation
Li, Yinan; Wang, Junbo; Luo, Zhenyu; Chen, Deyong; Chen, Jian
2015-01-01
Resonant pressure microsensors are widely used in the fields of aerospace exploration and atmospheric pressure monitoring due to their advantages of quasi-digital output and long-term stability, which, however, requires the use of additional temperature sensors for temperature compensation. This paper presents a resonant pressure microsensor capable of self-temperature compensation without the need for additional temperature sensors. Two doubly-clamped “H” type resonant beams were arranged on the pressure diaphragm, which functions as a differential output in response to pressure changes. Based on calibration of a group of intrinsic resonant frequencies at different pressure and temperature values, the functions with inputs of two resonant frequencies and outputs of temperature and pressure under measurement were obtained and thus the disturbance of temperature variations on resonant frequency shifts was properly addressed. Before compensation, the maximal errors of the measured pressure values were over 1.5% while after compensation, the errors were less than 0.01% of the full pressure scale (temperature range of −40 °C to 70 °C and pressure range of 50 kPa to 110 kPa). PMID:25938197
Non-resonant multipactor--A statistical model
NASA Astrophysics Data System (ADS)
Rasch, J.; Johansson, J. F.
2012-12-01
High power microwave systems operating in vacuum or near vacuum run the risk of multipactor breakdown. In order to avoid multipactor, it is necessary to make theoretical predictions of critical parameter combinations. These treatments are generally based on the assumption of electrons moving in resonance with the electric field while traversing the gap between critical surfaces. Through comparison with experiments, it has been found that only for small system dimensions will the resonant approach give correct predictions. Apparently, the resonance is destroyed due to the statistical spread in electron emission velocity, and for a more valid description it is necessary to resort to rather complicated statistical treatments of the electron population, and extensive simulations. However, in the limit where resonance is completely destroyed it is possible to use a much simpler treatment, here called non-resonant theory. In this paper, we develop the formalism for this theory, use it to calculate universal curves for the existence of multipactor, and compare with previous results. Two important effects that leads to an increase in the multipactor threshold in comparison with the resonant prediction are identified. These are the statistical spread of impact speed, which leads to a lower average electron impact speed, and the impact of electrons in phase regions where the secondary electrons are immediately reabsorbed, leading to an effective removal of electrons from the discharge.
NASA Astrophysics Data System (ADS)
Wei, Buzheng; Ren, Guobin; Jian, Shuisheng
2017-09-01
The plasmonic analogy from Fano resonance to Autler-Townes splitting (ATS) in mid-infrared spectral range is observed assisted by a dual parallel graphene-coated grating structure. The analytical derivation exhibits a height-dependent resonance which is crucial for discerning Fano resonance from ATS. The mechanism of generating a transparency window seeks a trade-off between Fano resonance and ATS at threshold height. While within the critical height, Fano resonance dominates. The Akaike Information Criterion test is used to discern these two effects quantitatively. Moreover, the device pronounces a good tunability accompanied with a slowing light application. Our ideas open up a new insight view of designing or constructing highly integrated, multi-functional graphene-based metamaterials in nanoscale.
Hogarth, Andrew J.; Artis, Nigel J.; Sivananthan, U. Mohan; Pepper, Chris B.
2011-01-01
Cardiac magnetic resonance imaging (MRI) is increasingly used as the optimum modality for cardiac imaging. An aging population and rising numbers of patients with permanent pacemakers means many such individuals may require cardiac MRI scanning in the future. Whilst the presence of a permanent pacemaker is historically regarded as a contra-indication to MRI scanning, pacemaker systems have been developed to limit any associated risks. No reports have been published regarding the use of such devices with cardiac MRI in a clinical setting. We present the safe, successful cardiac MRI scan of a patient with an MRI-conditional permanent pacing system. PMID:22355486
Resonant Phenomenon in a Stochastic Delayed Bistable Chemical System
NASA Astrophysics Data System (ADS)
Li, Chunxuan; Yang, Tao
2015-06-01
In this paper, the resonant phenomenon for a bistable chemical system in the presence of noises and delayed feedback is investigated. The signal-to-noise ratio (SNR) is calculated when periodic signal is introduced additively (or multiplicatively). The impacts of the parameter μ of the reaction, time delay τ, strength K of the feedback loop, multiplicative ( D) and additive ( Q) noise strengths and cross-correlation strength λ between two noises on the SNR are discussed. When the periodic signal is introduced additively, our results show (i) the SNR as a function of the parameter μ exhibits a maximum, the existence of the maximum is a characteristic of the parametric resonance (PR) phenomenon; (ii) the SNR as a function of D exhibits only a maximum, however, for the case of SNR as a function of Q exhibits not only a maximum, but also a minimum. The existence of the maximum and minimum in the SNR is the identifying characteristics of the stochastic resonance (SR) and reverse-resonance (RR); and (iii) the increases of τ, K and λ enhance the SR and weaken the RR. Finally, we compare the resonant phenomenon for the additive periodic signal with that for multiplicative one in the chemical system.
The diphoton resonance as a gravity mediator of dark matter
NASA Astrophysics Data System (ADS)
Han, Chengcheng; Lee, Hyun Min; Park, Myeonghun; Sanz, Verónica
2016-04-01
We consider the possibility of interpreting the recently reported diphoton excess at 750 GeV as a spin-two massive particle (such as a Kaluza-Klein graviton in warped extra-dimensions) which serves as a mediator to Dark Matter via its gravitational couplings to the dark sector and to the Standard Model (SM). We model non-universal couplings of the resonance to gauge bosons in the SM and to Dark Matter as a function on their localization in the extra dimension. We find that scalar, fermion or vector dark matter can saturate the dark matter relic density by the annihilation of dark matter into a pair of the SM particles or heavy resonances, in agreement with the diphoton resonance signal strength. We check the compatibility of our hypothesis with other searches for the KK graviton. We show that the invisible decay rate of the resonance into a pair of dark matter is subdominant in the region of the correct relic density, hence leading to no constraints from the mono-jet bound at 8 TeV via the gluon coupling. We also discuss the kinematic features of the decay products of a KK graviton to distinguish the KK graviton from the SM backgrounds or a scalar particle interpretation of the diphoton resonance.
Matrix Formalism for Spin Dynamics Near a Single Depolarization Resonance
Chao, Alexander W.; /SLAC
2005-10-26
A matrix formalism is developed to describe the spin dynamics in a synchrotron near a single depolarization resonance as the particle energy (and therefore its spin precession frequency) is varied in a prescribed pattern as a function of time such as during acceleration. This formalism is first applied to the case of crossing the resonance with a constant crossing speed and a finite total step size, and then applied also to other more involved cases when the single resonance is crossed repeatedly in a prescribed manner consisting of linear ramping segments or sudden jumps. How repeated crossings produce an interference behavior is discussed using the results obtained. For a polarized beam with finite energy spread, a spin echo experiment is suggested to explore this interference effect.
Zhang, Xinwang; Schemm, Nathan; Balkır, Sina
2011-03-01
Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR)-based chemical analysis systems have been widely utilized in various areas such as medicine, security, and academic research. In these applications, the power amplifier stage plays a key role in generating the required oscillating magnetic fields within a radio frequency coil that serves as the probe. However, the bulky size and relatively low efficiency of the traditional power amplification schemes employed present a bottleneck for the realization of compact sized and portable NMR and NQR systems. To address this problem, this work presents a class D voltage-switching power amplification scheme with novel fast-start and fast-stop functions that are suitable for generating ideal NMR and NQR excitation signals. Compared to the traditional analog power amplifiers (PAs), the proposed switched-mode PA can achieve significant improvement on the power efficiency as well as the physical volume. A PA circuit for portable NQR-based explosive detection systems has been designed and built using the proposed scheme with 1 kW possible maximum output power and 10 MHz maximum operating frequency. Test results show that the presented PA achieves more than 60% measured efficiency within a highly compact volume while sustaining fast start and stop of excitation signals in the order of microseconds.
A fiber-optic hydrophone with a cylindrical Helmholtz resonator
NASA Astrophysics Data System (ADS)
Wang, Zefeng; Hu, Yongming; Ni, Ming; Meng, Zhou; Luo, Hong
2007-11-01
A passive homodyne Michelson interferometric fiber-optic hydrophone with a single-hole cylindrical Helmholtz resonator has been manufactured. To validate the theoretical results that the fluid coefficient of viscosity has great influence on the maximum sensitivity at the resonant frequency, the acoustic sensitivity frequency response of the fiber-optic hydrophone has been measured in a standing-wave tank filled with castor oil. The viscosity coefficient of castor oil will change with the variation of the temperature. Experimental Results show that the fiber-optic hydrophone frequency responses of different temperature have identical form except that the maximum sensitivities are different. The acoustic sensitivities of low frequency are about -159dB re 1rad/μPa. While the maximum sensitivities near the measured resonant frequency of 800Hz go down with the fall of the temperature, i.e. with the increase of the viscosity coefficient, which is agree with the theoretical conclusions. This fiber-optic hydrophone is a prototype device for a class of sensors that used to eliminate aliasing in the future sonar systems.
Linear Coupling between Transverse Modes of a Nanomechanical Resonator
NASA Astrophysics Data System (ADS)
Truitt, Patrick; Hertzberg, Jared; Schwab, Keith
2013-03-01
Recently, several groups have identified a linear coupling between different vibrational modes of nanomechanical resonators. We report observations of such a coupling between the two transverse modes of a doubly-clamped Si3N4 resonator with transverse resonance frequencies of 8.4 and 8.7 MHz. The resonator is voltage biased with respect to a nearby gate electrode for capactive readout. Increasing the gate bias introduces an electrostatic contribution to the spring constant of each mode, reducing the frequency gap between the two modes. At degeneracy, we observe an avoided crossing of 100 kHz. Measurements of the displacement amplitudes and quality factors through degeneracy is consistent with a linear superposition of the two modes. Magnetomotive measurements, which are sensitive to the projection of each mode's displacement onto an applied field, show that the coupled modes remain linearly polarized, with the direction of polarization rotating with increasing gate bias. In an effort to identify the source of the coupling, we constructed a finite element model of the resonator-gate capacitance and find that the observed coupling is an order of magnitude larger than what is expected from electrostatic gradients alone.
Resonant microsphere gyroscope based on a double Faraday rotator system.
Xie, Chengfeng; Tang, Jun; Cui, Danfeng; Wu, Dajin; Zhang, Chengfei; Li, Chunming; Zhen, Yongqiu; Xue, Chenyang; Liu, Jun
2016-10-15
The resonant microsphere gyroscope is proposed based on a double Faraday rotator system for the resonant microsphere gyroscope (RMSG) that is characterized by low insertion losses and does not destroy the reciprocity of the gyroscope system. Use of the echo suppression structure and the orthogonal polarization method can effectively inhibit both the backscattering noise and the polarization error, and reduce them below the system sensitivity limit. The resonance asymmetry rate dropped from 34.2% to 2.9% after optimization of the backscattering noise and the polarization noise, which greatly improved the bias stability and the scale factor linearity of the proposed system. Additionally, based on the optimum parameters for the double Faraday rotator system, a bias stability of 0.04°/s has been established for an integration time of 10 s in 1000 s in a resonator microsphere gyroscope using a microsphere resonator with a diameter of 1 mm and a Q of 7.2×10^{6}.
A Wireless, Passive Load Cell based on Magnetoelastic Resonance.
Pereles, Brandon D; Dienhart, Thomas; Sansom, Thadeus; Johnston, Kyle; Ong, Keat Ghee
2012-07-01
A wireless, battery-less load cell was fabricated based on the resonant frequency shift of a vibrating magnetoelastic strip when exposed to an AC magnetic field. Since the vibration of the magnetoelastic strip generated a secondary field, the resonance was remotely detected with a coil. When a load was applied to a small area on the surface of the magnetoelastic strip via a circular rod applicator, the resonant frequency and amplitude decreased due to the damping on its vibration. The force sensitivity of the load cell was controlled by changing the size of the force applicator and placing the applicator at different locations on the strip's surface. Experimental results showed the force sensitivity increased with a larger applicator placing near the edge of the strip. The novelty of this load cell is not only its wireless passive nature, but also the controllability of the force sensitivity.
A Wireless, Passive Load Cell based on Magnetoelastic Resonance
Pereles, Brandon D.; Dienhart, Thomas; Sansom, Thadeus; Johnston, Kyle; Ong, Keat Ghee
2012-01-01
A wireless, battery-less load cell was fabricated based on the resonant frequency shift of a vibrating magnetoelastic strip when exposed to an AC magnetic field. Since the vibration of the magnetoelastic strip generated a secondary field, the resonance was remotely detected with a coil. When a load was applied to a small area on the surface of the magnetoelastic strip via a circular rod applicator, the resonant frequency and amplitude decreased due to the damping on its vibration. The force sensitivity of the load cell was controlled by changing the size of the force applicator and placing the applicator at different locations on the strip’s surface. Experimental results showed the force sensitivity increased with a larger applicator placing near the edge of the strip. The novelty of this load cell is not only its wireless passive nature, but also the controllability of the force sensitivity. PMID:22791938
Resonance at the Rabi frequency in a superconducting flux qubit
Greenberg, Ya. S.; Il'ichev, E.; Oelsner, G.; Shevchenko, S. N.
2014-10-15
We analyze a system composed of a superconducting flux qubit coupled to a transmission-line resonator driven by two signals with frequencies close to the resonator's harmonics. The first strong signal is used for exciting the system to a high energetic state while a second weak signal is applied for probing effective eigenstates of the system. In the framework of doubly dressed states we showed the possibility of amplification and attenuation of the probe signal by direct transitions at the Rabi frequency. We present a brief review of theoretical and experimental works where a direct resonance at Rabi frequency have been investigated in superconducting flux qubits. The interaction of the qubit with photons of two harmonics has prospects to be used as a quantum amplifier (microwave laser) or an attenuator.
Kinematic signature of a rotating bar near a resonance
NASA Technical Reports Server (NTRS)
Weinberg, Martin D.
1994-01-01
Recent work based on H I, star count and emission data suggests that the Milky Way has rotating bar-like features. In this paper, I show that such features cause distinctive stellar kinematic signatures near Outer Lindblad Resonance (OLR) and Inner Lindblad Resonance (ILR). The effect of these resonances may be observable far from the peak density of the pattern and relatively nearby the solar position. The details of the kinematic signatures depend on the evolutionary history of the 'bar' and therefore velocity data, both systematic and velocity dispersion, may be used to probe the evolutionary history as well as the present state of Galaxy. Kinematic models for a variety of sample scenarios are presented. Models with evolving pattern speeds show significantly stronger dispersion signatures than those with static pattern speeds, suggesting that useful observational constraints are possible. The models are applied to the proposed rotating spheroid and bar models; we find (1) none of these models chosen to represent the proposed large-scale rotating spheroid are consistent with the stellar kinematics and (2) a Galactic bar with semimajor axis of 3 kpc will cause a large increase in velocity dispersion in the vicinity of OLR (approximately 5 kpc) with little change in the net radial motion and such a signature is suggested by K-giant velocity data. Potential future observations and analyses are discussed.
A Dynamical Study of Resonances in Disk Galaxies
NASA Astrophysics Data System (ADS)
Treuthardt, P. M.; Buta, R. J.; Salo, H.
2005-05-01
Resonances in disk galaxies play a fundamental role in galactic evolution because resonant stars may exchange angular momentum with a pertubation and thereby strengthen or weaken it (Athanassoula 2003, MNRAS, 341, 1179). In many disk galaxies, resonance regions are visible as distinct inner, outer, and nuclear rings of star formation. These rings act as tracers of the associated perturbation's pattern speed (Ω p). One of two ways of estimating Ω p is the direct Tremaine-Weinberg (1984, ApJ, 282, 5) method, which uses luminosity-weighted positions and velocities along strips parallel to the major axis. The second and more indirect way, is the numerical simulation method (e.g. Salo et al. 1999, AJ, 117, 778), which matches a cloud-particle model to the observed gas distribution and velocity field. This poster describes our project to use both methods on a small sample of ringed spiral galaxies in order to test the resonance idea of galactic rings (Buta and Combes 1996, Fund. Cos. Phys. 17, 95) and also to determine if the two methods give consistent results. Focusing a pattern speed study on resonance ring galaxies has the benefit of constraints, provided by the rings, on the parameters governing morphology. Our numerical analysis is based on near-infrared images which are used to infer galactic gravitational potentials.
NASA Astrophysics Data System (ADS)
Dubowik, J.; Kuświk, P.; Matczak, M.; Bednarski, W.; Stobiecki, F.; Aleshkevych, P.; Szymczak, H.; Kisielewski, M.; Kisielewski, J.
2016-06-01
We present ferromagnetic resonance (FMR) investigations of 20 nm thick permalloy (Ni80Fe20 ) elements (width W =200 nm, length L =470 nm, period a =500 nm) arranged in open and closed artificial kagome lattices. The measurements were done at 9.4 and 34 GHz to ensure a saturated or near-saturated magnetic state of the kagome structures. The FMR data are analyzed in the framework of an analytical macrospin model which grasps the essential features of the bulk and edge modes at these microwave frequencies and is in agreement with the results of micromagnetic simulations. Polar plots of the resonance fields versus the field angle made by the direction of the magnetic field with respect to the main symmetry directions of the kagome lattice are compared with the results of the analytical model. The measured FMR spectra with a sixfold rotational symmetry qualitatively reproduce the structure expected from the theory. Magnetic dipolar interactions between the elements of the kagome lattices result in the mixing of edge and bulklike excitations at 9.4 GHz and in a systematic deviation from the model, especially for the closed kagome lattice.
Magnetic resonance imaging in entomology: a critical review
Hart, A.G.; Bowtell, R.W.; Köckenberger, W.; Wenseleers, T.; Ratnieks, F.L.W.
2003-01-01
Magnetic resonance imaging (MRI) enables in vivo imaging of organisms. The recent development of the magnetic resonance microscope (MRM) has enabled organisms within the size range of many insects to be imaged. Here, we introduce the principles of MRI and MRM and review their use in entomology. We show that MRM has been successfully applied in studies of parasitology, development, metabolism, biomagnetism and morphology, and the advantages and disadvantages relative to other imaging techniques are discussed. In addition, we illustrate the images that can be obtained using MRM. We conclude that although MRM has significant potential, further improvements to the technique are still desirable if it is to become a mainstream imaging technology in entomology. Abbreviation: CSI chemical shift imaging. The dependence of the resonance frequency of a nucleus on the chemical binding of the atom or molecule in which it is contained. (N)MRI (nuclear) magnetic resonance imaging MRM magnetic resonance microscopy Voxel A contraction for volume element, which is the basic unit of MR reconstruction; represented as a pixel in the display of the MR image. PMID:15841222
A new shape resonance in the Ps^- system
NASA Astrophysics Data System (ADS)
Ho, Yew Kam
2012-06-01
There have been continues experimental and theoretical investigations on the positronium negative ion (Ps^-), one of the simplest three-lepton systems interacting through Coulomb forces. In the present work, we use highly correlated Hylleraas wave functions up to N=1078 terms together with employing the complex-coordinate rotation method [1] to investigate resonances in the Ps^- system. We have located a new S-wave shape resonance lying above the Ps (n=2) threshold. Our preliminary results for the resonance parameters are Er = - 0.0498788 a.u. and γ / 2 = 0.0139470 a.u., where Er and γ denote the resonance energy and width, respectively. This stabilized complex eigenvalue has never been reported in the literature, to the best of our knowledge. Here, by changing the mass of the positively charged particle from one unit of the electron mass to infinitely heavy, we have traced this resonance pole from the positronium negative ion to the hydrogen negative ion [2]. Detailed calculations will be presented at the meeting. [4pt] [1]. Y. K. Ho, Phys. Reports 99, 1 (1983) and references therein. [0pt] [2]. A. Burgers and E. Lindroth, Euro. Phys. J. D 10, 327 (2000).
Acoustic resonance in the combustion conduits of a steam locomotive
Ziada, S.; Oengoeren, A.; Vogel, H.H.
1996-12-01
The sound emission of a modern, oil fired steam rack locomotive increased sharply when the locomotive speed exceeded the design value of 12 km/hr. The results of pressure and noise measurements, together with an acoustical model of the combustion conduits indicated that the acoustic resonance modes of the combustion conduits are excited by the pressure pulsations generated by the exhaust from the steam cylinders at multiples of the piston frequency. Additionally, when the acoustic resonance is initiated, the resulting pulsations trigger the flame instability of the oil burners which, in turn, enhances the resonance. By means of the acoustical model, a Helmholtz resonator has been designed and optimized to reduce the acoustic response such that it does not excite the flame instability. A second set of measurements, after installing the resonator, has shown a reduction in the noise level by an amount exceeding 21 dBA. The paper focuses upon the identification of the excitation source and the implementation of the countermeasure which are of interest to other applications involving combustion oscillations.
Proliferation detection using a remote resonance Raman chemical sensor
Sedlacek, A.J.; Chen, C.L.; Dougherty, D.R.
1993-08-01
The authors discussed the potential of the resonance Raman chemical sensor as a remote sensor that can be used for gases, liquids or solids. This spectroscopy has the fundamental advantage that it is based on optical fingerprints that are insensitive to environmental perturbations or excitation frequency. By taking advantage of resonance enhancement, the inelastic scattering cross-section can increase anywhere from 4 to 6 orders of magnitude which translates into increased sensing range or lower detection limits. It was also shown that differential cross-sections as small as 10{sup {minus}27} cm{sup 2}/sr do not preclude the use of this technique as being an important component in one`s remote-sensing arsenal. The results obtained in the early 1970s on various pollutants and the more recent work on atmospheric water cast a favorable light on the prospects for the successful development of a resonance Raman remote sensor. Currently, of the 20 CW agent-related {open_quotes}signature{close_quotes} chemicals that the authors have investigated, 18 show enhancements ranging from 3 to 6 orders of magnitude. The absolute magnitudes of the measured resonance enhanced Raman cross-sections for these 18 chemicals suggest that detection and identification of trace quantities of the {open_quotes}signature{close_quotes} chemicals, through a remote resonance Raman chemical sensor, could be achieved.
Reducing flow-induced resonance in a cavity
NASA Technical Reports Server (NTRS)
Cattafesta, III, Louis N. (Inventor); Wlezien, Richard W. (Inventor); Won, Chin C. (Inventor); Garg, Sanjay (Inventor)
1998-01-01
A method and system are provided for reducing flow-induced resonance in a structure's cavity. A time-varying disturbance is introduced into the flow along a leading edge of the cavity. The time-varying disturbance can be periodic and can have the same or different frequency of the natural resonant frequency of the cavity. In one embodiment of the system, flaps are mounted flush with the surface of the structure along the cavity's leading edge. A piezoelectric actuator is coupled to each flap and causes a portion of each flap to oscillate into and out of the flow in accordance with the time-varying function. Resonance reduction can be achieved with both open-loop and closed-loop configurations of the system.
A quadratic-shaped-finger comb parametric resonator
NASA Astrophysics Data System (ADS)
Guo, Congzhong; Fedder, Gary K.
2013-09-01
A large-stroke (8 µm) parametric resonator excited by an in-plane ‘shaped-finger’ electrostatic comb drive is fabricated using a 15 µm thick silicon-on-insulator microelectromechanical systems (SOI-MEMS) process. A quadratic capacitance-engagement response is synthesized by engineering a custom-shaped comb finger profile. A folded-flexure suspension allows lateral motion while constraining rotational modes. The excitation of the nonlinear parametric resonance is realized by selecting an appropriate combination of the linear and cubic electrostatic stiffness coefficients through a specific varying-gap comb-finger design. The large-amplitude parametric resonance promotes high signal-to-noise ratio for potential use in sensitive chemical gravimetric sensors, strain gauges, and mode-matched gyroscope applications.
Vibrational resonance in a time-delayed genetic toggle switch
NASA Astrophysics Data System (ADS)
Daza, Alvar; Wagemakers, Alexandre; Rajasekar, Shanmuganathan; Sanjuán, Miguel A. F.
2013-02-01
Biological oscillators can respond in a surprising way when they are perturbed by two external periodic forcing signals of very different frequencies. The response of the system to a low-frequency signal can be enhanced or depressed when a high-frequency signal is acting. This is what is known as vibrational resonance (VR). Here we study this phenomenon in a simple time-delayed genetic toggle switch, which is a synthetic gene-regulatory network. We have found out how the low-frequency signal changes the range of the response, while the high-frequency signal influences the amplitude at which the resonance occurs. The delay of the toggle switch has also a strong effect on the resonance since it can also induce autonomous oscillations.
Design and Analyses of a MEMS Based Resonant Magnetometer.
Ren, Dahai; Wu, Lingqi; Yan, Meizhi; Cui, Mingyang; You, Zheng; Hu, Muzhi
2009-01-01
A novel design of a MEMS torsional resonant magnetometer based on Lorentz force is presented and fabricated. The magnetometer consists of a silicon resonator, torsional beam, excitation coil, capacitance plates and glass substrate. Working in a resonant condition, the sensor's vibration amplitude is converted into the sensing capacitance change, which reflects the outside magnetic flux-density. Based on the simulation, the key structure parameters are optimized and the air damping effect is estimated. The test results of the prototype are in accordance with the simulation results of the designed model. The resolution of the magnetometer can reach 30 nT. The test results indicate its sensitivity of more than 400 mV/μT when operating in a 10 Pa vacuum environment.
Design and Analyses of a MEMS Based Resonant Magnetometer
Ren, Dahai; Wu, Lingqi; Yan, Meizhi; Cui, Mingyang; You, Zheng; Hu, Muzhi
2009-01-01
A novel design of a MEMS torsional resonant magnetometer based on Lorentz force is presented and fabricated. The magnetometer consists of a silicon resonator, torsional beam, excitation coil, capacitance plates and glass substrate. Working in a resonant condition, the sensor’s vibration amplitude is converted into the sensing capacitance change, which reflects the outside magnetic flux-density. Based on the simulation, the key structure parameters are optimized and the air damping effect is estimated. The test results of the prototype are in accordance with the simulation results of the designed model. The resolution of the magnetometer can reach 30 nT. The test results indicate its sensitivity of more than 400 mV/μT when operating in a 10 Pa vacuum environment. PMID:22399981
Spin-torque driven ferromagnetic resonance in a nonlinear regime
NASA Astrophysics Data System (ADS)
Chen, W.; de Loubens, G.; Beaujour, J.-M. L.; Sun, J. Z.; Kent, A. D.
2009-10-01
Spin-valve based nanojunctions incorporating Co form="infix">∣Ni multilayers with perpendicular anisotropy were used to study spin-torque driven ferromagnetic resonance (ST-FMR) in a nonlinear regime. Perpendicular field swept resonance lines were measured under a large amplitude microwave current excitation, which produces a large angle precession of the Co form="infix">∣Ni layer magnetization. With increasing rf power the resonance lines broaden and become asymmetric, with their peak shifting to lower applied field. A nonhysteretic step jump in ST-FMR voltage signal was also observed at high powers. The results are analyzed in terms of the foldover effect of a forced nonlinear oscillator and compared to macrospin simulations. The ST-FMR nonhysteretic step response may have applications in frequency and amplitude tunable nanoscale field sensors.
Arrangement for damping the resonance in a laser diode
NASA Technical Reports Server (NTRS)
Katz, J.; Yariv, A.; Margalit, S. (Inventor)
1985-01-01
An arrangement for damping the resonance in a laser diode is described. This arrangement includes an additional layer which together with the conventional laser diode form a structure (35) of a bipolar transistor. Therein, the additional layer serves as the collector, the cladding layer next to it as the base, and the active region and the other cladding layer as the emitter. A capacitor is connected across the base and the collector. It is chosen so that at any frequency above a certain selected frequency which is far below the resonance frequency the capacitor impedance is very low, effectively shorting the base to the collector.
Design and Implementation of a Micromechanical Silicon Resonant Accelerometer
Huang, Libin; Yang, Hui; Gao, Yang; Zhao, Liye; Liang, Jinxing
2013-01-01
The micromechanical silicon resonant accelerometer has attracted considerable attention in the research and development of high-precision MEMS accelerometers because of its output of quasi-digital signals, high sensitivity, high resolution, wide dynamic range, anti-interference capacity and good stability. Because of the mismatching thermal expansion coefficients of silicon and glass, the micromechanical silicon resonant accelerometer based on the Silicon on Glass (SOG) technique is deeply affected by the temperature during the fabrication, packaging and use processes. The thermal stress caused by temperature changes directly affects the frequency output of the accelerometer. Based on the working principle of the micromechanical resonant accelerometer, a special accelerometer structure that reduces the temperature influence on the accelerometer is designed. The accelerometer can greatly reduce the thermal stress caused by high temperatures in the process of fabrication and packaging. Currently, the closed-loop drive circuit is devised based on a phase-locked loop. The unloaded resonant frequencies of the prototype of the micromechanical silicon resonant accelerometer are approximately 31.4 kHz and 31.5 kHz. The scale factor is 66.24003 Hz/g. The scale factor stability is 14.886 ppm, the scale factor repeatability is 23 ppm, the bias stability is 23 μg, the bias repeatability is 170 μg, and the bias temperature coefficient is 0.0734 Hz/°C. PMID:24256978
Design and implementation of a micromechanical silicon resonant accelerometer.
Huang, Libin; Yang, Hui; Gao, Yang; Zhao, Liye; Liang, Jinxing
2013-11-19
The micromechanical silicon resonant accelerometer has attracted considerable attention in the research and development of high-precision MEMS accelerometers because of its output of quasi-digital signals, high sensitivity, high resolution, wide dynamic range, anti-interference capacity and good stability. Because of the mismatching thermal expansion coefficients of silicon and glass, the micromechanical silicon resonant accelerometer based on the Silicon on Glass (SOG) technique is deeply affected by the temperature during the fabrication, packaging and use processes. The thermal stress caused by temperature changes directly affects the frequency output of the accelerometer. Based on the working principle of the micromechanical resonant accelerometer, a special accelerometer structure that reduces the temperature influence on the accelerometer is designed. The accelerometer can greatly reduce the thermal stress caused by high temperatures in the process of fabrication and packaging. Currently, the closed-loop drive circuit is devised based on a phase-locked loop. The unloaded resonant frequencies of the prototype of the micromechanical silicon resonant accelerometer are approximately 31.4 kHz and 31.5 kHz. The scale factor is 66.24003 Hz/g. The scale factor stability is 14.886 ppm, the scale factor repeatability is 23 ppm, the bias stability is 23 μg, the bias repeatability is 170 μg, and the bias temperature coefficient is 0.0734 Hz/°C.
Acoustic resonances in cylinder bundles oscillating in a compressibile fluid
Lin, W.H.; Raptis, A.C.
1984-12-01
This paper deals with an analytical study on acoustic resonances of elastic oscillations of a group of parallel, circular, thin cylinders in an unbounded volume of barotropic, compressible, inviscid fluid. The perturbed motion of the fluid is assumed due entirely to the flexural oscillations of the cylinders. The motion of the fluid disturbances is first formulated in a three-dimensional wave form and then casted into a two-dimensional Helmholtz equation for the harmonic motion in time and in axial space. The acoustic motion in the fluid and the elastic motion in the cylinders are solved simultaneously. Acoustic resonances were approximately determined from the secular (eigenvalue) equation by the method of successive iteration with the use of digital computers for a given set of the fluid properties and the cylinders' geometry and properties. Effects of the flexural wavenumber and the configuration of and the spacing between the cylinders on the acoustic resonances were thoroughly investigated.
A platform for designing hyperpolarized magnetic resonance chemical probes
Nonaka, Hiroshi; Hata, Ryunosuke; Doura, Tomohiro; Nishihara, Tatsuya; Kumagai, Keiko; Akakabe, Mai; Tsuda, Masashi; Ichikawa, Kazuhiro; Sando, Shinsuke
2013-01-01
Hyperpolarization is a highly promising technique for improving the sensitivity of magnetic resonance chemical probes. Here we report [15N, D9]trimethylphenylammonium as a platform for designing a variety of hyperpolarized magnetic resonance chemical probes. The platform structure shows a remarkably long 15N spin–lattice relaxation value (816 s, 14.1 T) for retaining its hyperpolarized spin state. The extended lifetime enables the detection of the hyperpolarized 15N signal of the platform for several tens of minutes and thus overcomes the intrinsic short analysis time of hyperpolarized probes. Versatility of the platform is demonstrated by applying it to three types of hyperpolarized chemical probes: one each for sensing calcium ions, reactive oxygen species (hydrogen peroxide) and enzyme activity (carboxyl esterase). All of the designed probes achieve high sensitivity with rapid reactions and chemical shift changes, which are sufficient to allow sensitive and real-time monitoring of target molecules by 15N magnetic resonance. PMID:24022444
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
NASA Astrophysics Data System (ADS)
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.
Dynamic nuclear polarization in a magnetic resonance force microscope experiment.
Issac, Corinne E; Gleave, Christine M; Nasr, Paméla T; Nguyen, Hoang L; Curley, Elizabeth A; Yoder, Jonilyn L; Moore, Eric W; Chen, Lei; Marohn, John A
2016-04-07
We report achieving enhanced nuclear magnetization in a magnetic resonance force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic nuclear polarization (DNP) effect. In our experiments a microwire coplanar waveguide delivered radiowaves to excite nuclear spins and microwaves to excite electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both electron and proton spin resonance were observed as a change in the mechanical resonance frequency of a nearby cantilever having a micron-scale nickel tip. NMR signal, not observable from Curie-law magnetization at 0.6 T, became observable when microwave irradiation was applied to saturate the electron spins. The resulting NMR signal's size, buildup time, dependence on microwave power, and dependence on irradiation frequency was consistent with a transfer of magnetization from electron spins to nuclear spins. Due to the presence of an inhomogeneous magnetic field introduced by the cantilever's magnetic tip, the electron spins in the sample were saturated in a microwave-resonant slice 10's of nm thick. The spatial distribution of the nuclear polarization enhancement factor ε was mapped by varying the frequency of the applied radiowaves. The observed enhancement factor was zero for spins in the center of the resonant slice, was ε = +10 to +20 for spins proximal to the magnet, and was ε = -10 to -20 for spins distal to the magnet. We show that this bipolar nuclear magnetization profile is consistent with cross-effect DNP in a ∼10(5) T m(-1) magnetic field gradient. Potential challenges associated with generating and using DNP-enhanced nuclear magnetization in a nanometer-resolution magnetic resonance imaging experiment are elucidated and discussed.
Diode Laser Optically Injected by Resonance of a Monolithic Cavity
NASA Astrophysics Data System (ADS)
Peng, Yu; Zhao, Yang; Li, Ye; Yang, Tao; Cao, Jian-Ping; Fang, Zhan-Jun; Zang, Er-Jun
2011-11-01
We demonstrate a self-injection locking extended cavity diode laser (ECDL) using resonant optical feedback from the p-polarization of a monolithic folded Fabry—Perot parallel cavity (MFC). The full width at half maximum of the MFC resonance is 31 MHz. With the help of a narrow-linewidth reference laser, the linewidth of the ECDL is measured to be about 7 kHz. The frequency of the laser could be tuned at 160 MHz with an amplitude of 40 V by a PZT mounted on the monolithic cavity and the voltage tuning coefficient is about 4 MHz/V.
Photon transfer in a system of coupled superconducting microwave resonators
Muirhead, C. M. Gunupudi, B.; Colclough, M. S.
2016-08-28
A novel scheme is proposed for the study of energy transfer in a pair of coupled thin film superconducting microwave resonators. We show that the transfer could be achieved by modulating the kinetic inductance and that this has a number of advantages over earlier theoretical and experimental schemes, which use modulation of capacitance by vibrating nanobars or membranes. We show that the proposed scheme lends itself to the study of the classical analogues of Rabi and Landau-Zener-Stueckelberg oscillations and Landau-Zener transitions using experimentally achievable parameters. We consider a number of ways in which energy transfer (photon shuttle) between the two resonators could be achieved experimentally.
Photon transfer in a system of coupled superconducting microwave resonators
NASA Astrophysics Data System (ADS)
Muirhead, C. M.; Gunupudi, B.; Colclough, M. S.
2016-08-01
A novel scheme is proposed for the study of energy transfer in a pair of coupled thin film superconducting microwave resonators. We show that the transfer could be achieved by modulating the kinetic inductance and that this has a number of advantages over earlier theoretical and experimental schemes, which use modulation of capacitance by vibrating nanobars or membranes. We show that the proposed scheme lends itself to the study of the classical analogues of Rabi and Landau-Zener-Stueckelberg oscillations and Landau-Zener transitions using experimentally achievable parameters. We consider a number of ways in which energy transfer (photon shuttle) between the two resonators could be achieved experimentally.
A second generation of low thermal noise cryogenic silicon resonators
NASA Astrophysics Data System (ADS)
Matei, D. G.; Legero, T.; Grebing, Ch; Häfner, S.; Lisdat, Ch; Weyrich, R.; Zhang, W.; Sonderhouse, L.; Robinson, J. M.; Riehle, F.; Ye, J.; Sterr, U.
2016-06-01
We have set up an improved vertically mounted silicon cavity operating at the zero-crossing temperature of the coefficient of thermal expansion (CTE) near 123 K with estimated thermal noise limited instability of 4 x 10-17 in the modified Allan deviation. Owing to the anisotropic elasticity of single-crystal silicon, the vertical acceleration sensitivity was minimized in situ by axially rotating the resonator with respect to the mounting frame. The control of the resonator temperature is greatly improved by using a combination of two thermal shields, monitoring with several temperature sensors, and employing low-thermal conductivity materials. The instability of the resonator stabilized laser was characterized by comparing with another low-noise system based on a 48 cm long room temperature cavity of PTB's strontium lattice clock, resulting in a modified Allan deviation of 7 x 10-17 at 100 s.
Surface Plasmon Resonance: A Versatile Technique for Biosensor Applications
Nguyen, Hoang Hiep; Park, Jeho; Kang, Sebyung; Kim, Moonil
2015-01-01
Surface plasmon resonance (SPR) is a label-free detection method which has emerged during the last two decades as a suitable and reliable platform in clinical analysis for biomolecular interactions. The technique makes it possible to measure interactions in real-time with high sensitivity and without the need of labels. This review article discusses a wide range of applications in optical-based sensors using either surface plasmon resonance (SPR) or surface plasmon resonance imaging (SPRI). Here we summarize the principles, provide examples, and illustrate the utility of SPR and SPRI through example applications from the biomedical, proteomics, genomics and bioengineering fields. In addition, SPR signal amplification strategies and surface functionalization are covered in the review. PMID:25951336
A modern Michelson-Morley experiment using ultrastable optical resonators
NASA Astrophysics Data System (ADS)
Peters, Achim
2005-05-01
This talk will describe a modern version of the classic Michelson-Morley experiment testing the isotropy of light propagation and thus the foundations of Special Relativity. The latest experimental setup employs of an assembly of orthogonal ultrastable optical resonators mounted inside a liquid Helium cryostat, which itself is actively rotated using a high performance air-supported turntable. The cavity resonance frequencies are continuously monitored using monolithic Nd:YAG lasers and analyzed for periodic modulations indicating violations of Lorentz-invariance. Compared to pervious experiments using cryogenic optical resonators (COREs), but relying solely on Earth's rotation, this new version is expected to lead to orders of magnitude improvement in sensitivity to Lorentz-Invariance violation. We present the initial results of this experimental effort at the δc(θ)/c ˜ 10-16 level for an direction dependent variation of the speed of light and discuss the potential for future improvements.
Ultracold Molecule Production via a Resonant Oscillating Magnetic Field
Thompson, S.T.; Hodby, E.; Wieman, C.E.
2005-11-04
A novel atom-molecule conversion technique has been investigated. Ultracold {sup 85}Rb atoms sitting in a dc magnetic field near the 155 G Feshbach resonance are associated by applying a small sinusoidal oscillation to the magnetic field. There is resonant atom to molecule conversion when the modulation frequency closely matches the molecular binding energy. We observe that the atom to molecule conversion efficiency depends strongly on the frequency, amplitude, and duration of the applied modulation and on the phase space density of the sample. This technique offers high conversion efficiencies without the necessity of crossing or closely approaching the Feshbach resonance and allows precise spectroscopic measurements. Efficiencies of 55% have been observed for pure Bose-Einstein condensates.
Anthropogenic sources stimulate resonance of a natural rock bridge
NASA Astrophysics Data System (ADS)
Moore, Jeffrey R.; Thorne, Michael S.; Koper, Keith D.; Wood, John R.; Goddard, Kyler; Burlacu, Relu; Doyle, Sarah; Stanfield, Erik; White, Benjamin
2016-09-01
The natural modes of vibration of bedrock landforms, as well as the sources and effects of stimulated resonance remain poorly understood. Here we show that seismic energy created by an induced earthquake and an artificial reservoir has spectral content coincident with the natural modes of vibration of a prominent rock bridge. We measured the resonant frequencies of Rainbow Bridge, Utah using data from two broadband seismometers placed on the span, and identified eight distinct vibrational modes between 1 and 6 Hz. A distant, induced earthquake produced local ground motion rich in 1 Hz energy, stimulating a 20 dB increase in measured power at the bridge's fundamental mode. Moreover, we establish that wave action on Lake Powell, an artificial reservoir, generates microseismic energy with peak power ~1 Hz, also exciting resonance of Rainbow Bridge. These anthropogenic sources represent relatively new energy input for the bridge with unknown consequences for structural fatigue.
Fermi resonance as a tool for probing peridinin environment.
Kish, Elizabeth; Mendes Pinto, Maria Manuela; Bovi, Daniele; Basire, Marie; Guidoni, Leonardo; Vuilleumier, Rodolphe; Robert, Bruno; Spezia, Riccardo; Mezzetti, Alberto
2014-06-05
In the present paper, we provide an extended study of the vibrational signature of a butenolide carotenoid, peridinin, in various solvents by combining resonance Raman spectroscopy (RRS) with theoretical calculations. The presence of a Fermi resonance due to coupling between the lactonic C═O stretching and the overtone of the wagging of the C-H in the lactonic ring provides a spectroscopic way of differentiating between peridinins lying in different environments. This is a significant achievement, given that simultaneous presence of several peridinins (each with a peculiar photophysical role) in different environments occurs in the most important peridinin containing proteins, the peridinin-chlorophyll proteins (PCPs) and the Chl a-c2-peridinin binding proteins. In RRS, small modifications of solvent polarity can give rise to large differences in the intensity and splitting between the two bands, resulting from the Fermi resonance. By changing the polarity, we can tune the frequency of stretching of the C═O and, while the C-H wagging frequency is almost always constant in different solvents, move the system from a perfect resonance condition to off-resonance ones. We have corroborated our spectroscopic findings with a quasi-classical dynamical model of two coupled oscillators, and DFT calculations on peridinin in different solvents; we have also used calculations to complete the peridinin vibrational mode assignments in the 800-1600 cm(-1) region of RRS spectra, corresponding to polyene chain motion. Finally, the presence of Fermi resonance has been used to reinterpret previous vibrational spectroscopic experiments in PCPs.
Statistical Assignment of Neutron Orbital Angular Momentum to a Resonance
Oh, Soo-Youl; Chang, Jonghwa; Leal, Luiz C.
2004-09-15
We have derived formulas in a general form for suggesting the neutron orbital angular momentum quantum number l to each neutron resonance if it is not identified experimentally. By assuming the (2J + 1) law of level density, these general formulas are reduced to the formulas found in previous works. The suggestion of l is based on the probability that a resonance having a certain value of g{gamma}{sub n} is an l-wave resonance. The probability is calculated from the Bayes theorem on conditional probability. For each l, the probability density function (pdf) of g{gamma}{sub n} was derived from the {chi}{sup 2} distribution proposed by Porter and Thomas. The pdf takes into account two possible channel spins that result in the same total spin for a given l larger than zero. Meanwhile, regardless of the resolution of measurement, we suggest adopting the level density as the prior probability in the Bayesian approach, as Gyulassy et al. did. As a sample problem, we presented the result of l-assignment for {sup 109}Ag resonances. The SUGGEL code, in which the methodology is incorporated, correctly assigned l's for 67 among 70 resonances for which l's had been determined experimentally. The other test for {sup 27}Al showed the applicability of the code as a preanalysis tool, even though such applicability is limited to a certain extent for light nuclides. The use of the code SUGGEL is expected to reduce the number of repeated runs of a fitting code such as SAMMY, thus reducing time and effort for the extraction of resonance parameters from measurements.
The RANLUX Generator:. Resonances in a Random Walk Test
NASA Astrophysics Data System (ADS)
Shchur, Lev N.; Butera, Paolo
Using a recently proposed directed random walk test, we systematically investigate the popular random number generator RANLUX developed by Lüscher and implemented by James. We confirm the good quality of this generator with the recommended luxury level. At a smaller luxury level (for instance equal to 1) resonances are observed in the random walk test. We also find that the lagged Fibonacci and Subtract-with-Carry recipes exhibit similar failures in the random walk test. A revised analysis of the corresponding dynamical systems leads to the observation of resonances in the eigenvalues of Jacobi matrix.
Orbital trajectory of an acoustic bubble in a cylindrical resonator.
Desjouy, Cyril; Labelle, Pauline; Gilles, Bruno; Bera, Jean-Christophe; Inserra, Claude
2013-09-01
Acoustic cavitation-induced microbubbles in a cylindrical resonator filled with water tend to concentrate into ring patterns due to the cylindrical geometry of the system. The shape of these ring patterns is directly linked to the Bjerknes force distribution in the resonator. Experimental observations showed that cavitation bubbles located in the vicinity of this ring may exhibit a spiraling behavior around the pressure nodal line. This spiraling phenomenon is numerically studied, the conditions for which a single cavitation bubble follows an orbital trajectory are established, and the influences of the acoustic pressure amplitude and the initial bubble radius are investigated.
Magnetic resonance imaging as a tool for extravehicular activity analysis
NASA Technical Reports Server (NTRS)
Dickenson, R.; Lorenz, C.; Peterson, S.; Strauss, A.; Main, J.
1992-01-01
The purpose of this research is to examine the value of magnetic resonance imaging (MRI) as a means of conducting kinematic studies of the hand for the purpose of EVA capability enhancement. After imaging the subject hand using a magnetic resonance scanner, the resulting 2D slices were reconstructed into a 3D model of the proximal phalanx of the left hand. Using the coordinates of several landmark positions, one is then able to decompose the motion of the rigid body. MRI offers highly accurate measurements due to its tomographic nature without the problems associated with other imaging modalities for in vivo studies.
Magnetic resonance imaging as a tool for extravehicular activity analysis
NASA Technical Reports Server (NTRS)
Dickenson, R.; Lorenz, C.; Peterson, S.; Strauss, A.; Main, J.
1992-01-01
The purpose of this research is to examine the value of magnetic resonance imaging (MRI) as a means of conducting kinematic studies of the hand for the purpose of EVA capability enhancement. After imaging the subject hand using a magnetic resonance scanner, the resulting 2D slices were reconstructed into a 3D model of the proximal phalanx of the left hand. Using the coordinates of several landmark positions, one is then able to decompose the motion of the rigid body. MRI offers highly accurate measurements due to its tomographic nature without the problems associated with other imaging modalities for in vivo studies.
A new algorithm for reliable and general NMR resonance assignment.
Schmidt, Elena; Güntert, Peter
2012-08-01
The new FLYA automated resonance assignment algorithm determines NMR chemical shift assignments on the basis of peak lists from any combination of multidimensional through-bond or through-space NMR experiments for proteins. Backbone and side-chain assignments can be determined. All experimental data are used simultaneously, thereby exploiting optimally the redundancy present in the input peak lists and circumventing potential pitfalls of assignment strategies in which results obtained in a given step remain fixed input data for subsequent steps. Instead of prescribing a specific assignment strategy, the FLYA resonance assignment algorithm requires only experimental peak lists and the primary structure of the protein, from which the peaks expected in a given spectrum can be generated by applying a set of rules, defined in a straightforward way by specifying through-bond or through-space magnetization transfer pathways. The algorithm determines the resonance assignment by finding an optimal mapping between the set of expected peaks that are assigned by definition but have unknown positions and the set of measured peaks in the input peak lists that are initially unassigned but have a known position in the spectrum. Using peak lists obtained by purely automated peak picking from the experimental spectra of three proteins, FLYA assigned correctly 96-99% of the backbone and 90-91% of all resonances that could be assigned manually. Systematic studies quantified the impact of various factors on the assignment accuracy, namely the extent of missing real peaks and the amount of additional artifact peaks in the input peak lists, as well as the accuracy of the peak positions. Comparing the resonance assignments from FLYA with those obtained from two other existing algorithms showed that using identical experimental input data these other algorithms yielded significantly (40-142%) more erroneous assignments than FLYA. The FLYA resonance assignment algorithm thus has the
A 10-GHz film-thickness-mode cavity optomechanical resonator
NASA Astrophysics Data System (ADS)
Han, Xu; Fong, King Y.; Tang, Hong X.
2015-04-01
We report on the advance of chip-scale cavity optomechanical resonators to beyond 10 GHz by exploiting the fundamental acoustic thickness mode of an aluminum nitride micro-disk. By engineering the mechanical anchor to minimize the acoustic loss, a quality factor of 1830 and hence a frequency-quality factor product of 1.9 × 1013 Hz are achieved in ambient air at room temperature. Actuated by strong piezo-electric force, the micro-disk resonator shows an excellent electro-optomechanical transduction efficiency. Our detailed analysis of the electro-optomechanical coupling allows identification and full quantification of various acoustic modes spanning from super-high to X-band microwave frequencies measured in the thin film resonator.
A simple mechanical model for resonance absorption: The Alfvén resonance
NASA Astrophysics Data System (ADS)
Hollweg, Joseph V.
1997-10-01
We consider resonance absorption of magnetohydrodynamic waves, and the Alfvén resonance layer in particular. We show that the dissipative layer can be modeled as a simple mechanical system consisting of a few harmonic oscillators which are coupled by friction. The mechanical model reproduces known results for the externally driven system in steady state, such as the structure of the dissipative layer, the ``waves'' of heating which propagate across the layer, and the fact that the total heating is independent of time. The total work done on the oscillators by the driver is always positive; the external driver sees the total system as a single damped oscillator driven exactly at resonance. Nonetheless, some of the oscillators return energy back to the driver. The total kinetic energy of all the oscillators and the total potential energy are nearly independent of time, because the integrals, across the dissipative layer, of the square of the velocity and the square of the displacement, are truly constants in time. Waves of kinetic and potential energy propagate across the system in the same sense as the waves of heating. We also investigate an initial value problem in which the driver is turned on at t=0. There is no single number representing the time required for the dissipative layer to reach a steady state. The waves of heating which are found in the steady state are also present in the buildup phase. However, if the driver is turned off after the system has reached a steady state, then the waves of heating are less obvious. We consider the effects of a nonlinear frictional coupling between the oscillators, designed to mimic the effects of Kelvin-Helmholtz instabilities. The nonlinear coupling has surprisingly little effect on the system. The total steady state heating rate is the same as in the linear system; even with nonlinear dissipation, the dissipative layer adjusts itself to absorb a predetermined amount of energy being pumped in by the external driver
Electron Paramagnetic Resonance of Single Magnetic Moment on a Surface
Berggren, P.; Fransson, J.
2016-01-01
We address electron spin resonance of single magnetic moments in a tunnel junction using time-dependent electric fields and spin-polarized current. We show that the tunneling current directly depends on the local magnetic moment and that the frequency of the external electric field mixes with the characteristic Larmor frequency of the local spin. The importance of the spin-polarized current induced anisotropy fields acting on the local spin moment is, moreover, demonstrated. Our proposed model thus explains the absence of an electron spin resonance for a half integer spin, in contrast with the strong signal observed for an integer spin. PMID:27156935
Glashow resonance as a window into cosmic neutrino sources
NASA Astrophysics Data System (ADS)
Barger, V.; Fu, Lingjun; Learned, J. G.; Marfatia, D.; Pakvasa, S.; Weiler, T. J.
2014-12-01
The Glashow resonance at Eν=6.3 PeV is a measure of the ν¯ e content of the astrophysical neutrino flux. The fractional ν¯e content depends on the neutrino production model at the cosmic neutrino source, and the environment at the source. Thus, the strength of the Glashow resonance event rate is a potential window into astrophysical sources. We quantify the "Glashow resonometer" and comment on the significance that no Glashow events are observed in the IceCube three-year data.
Field Line Resonance at Mercury's Magnetosphere: A Simulation Study
Eun-Hwa Kim, Jay R. Johnson, and Dong-Hun Lee
2008-05-22
Ultra low frequency (ULF) waves, which are assumed to be standing waves on the field, are observed by the Mariner 10 spacecraft at Mercury. These waves are oscillating at 38% of the proton gyrofrequency. It is well known that the heavy ions, such as Na+, are abundant in Mercury's magnetosphere. Because the presence of different ion species has an influence on the plasma dispersion characteristics near the ion gyro-frequencies, such relatively high frequencies of magnetospheric eigenoscillations at Mercury require a multi-fluid treatment for the plasma. Thus ULF waves at Mercury may have a distinct difference from typical ULF oscillations at Earth, which are often described in terms of magnetohydrodynamics (MHD). By adopting a multi-fluid numerical wave model, we examine how magnetic eigenoscillations occur in Mercury's magnetosphere. Because protons and sodium ions are the main constituents at Mercury, we assume an electron-proton- sodium plasma in our model. The frequency spectra and time histories of the electromagnetic fields at the ion-ion hybrid (IIH) and cavity resonances are presented. Our results show: (1) The observed ULF waves are likely compressional waves rather than FLR. (2) Resonant absorption occurs at the IIH resonance, thus incoming compressional waves are converted into the IIH resonance. (3) The IIH resonance is strongly guided by the background magnetic field and shows linear polarization in the east-west meridian. (4) Both the Alfvén and the IIH are suggested as a mechanism for FLR at Mercury. (5) The resonance frequency enables us to estimate the local heavy ion concentration ratio.
A widely tunable laser using silica-waveguide ring resonators
NASA Astrophysics Data System (ADS)
Yamazaki, Hiroyuki; Takahashi, Morio; Suzuki, Kouichi; Deki, Yukari; Takeuchi, Takeshi; Takaesu, Sekizen; Horie, Mika; Sato, Kenji; Kudo, Koji
2005-10-01
A Wide wavelength tunable laser is needed for Wavelength Division Multiplexing (WDM) and Reconfigurable Optical Add/Drop Multiplexing (ROADM) networks, since it realizes flexible network, effectively employing wavelength resources, and inventory cost reduction. Several types currently exist, but they all are difficult to produce; that is, their mass producibility is not high and they have many components. In particular, monolithically integrated wavelength tunable lasers, such as DFB array, and SG(Sampled Grating)-DBR based structures, have been developed. While these lasers have good performance, they require complex InP growth steps and processing. The external cavity lasers also have good performance, but require precise manual assembly and have moving parts. We have proposed novel tunable laser consisting of silica waveguide ring resonator connected directly to semiconductor optical amplifier. This laser structure has several advantages, such as a simple laser structure suitable for mass-production and high reliability due to having a stable thermal optic phase shifter and no moving parts. This paper gives recent progress in waveguide ring resonator based tunable laser. Low loss and high performance silica waveguide ring resonator, which was suitable for tunable laser, was successfully fabricated using high index contrast SiON core. Double-ring resonators successfully attained 45-nm and 160-nm wavelength tuning operations, which was the largest wavelength tuning range in a tunable laser with no mechanical moving parts reported to date. Triple-ring resonator demonstrated stable full L-band tuning operations with 50-GHz wavelength spacing. We believe that silica waveguide ring resonator based tunable laser is very suitable for not only mass production, but also widely wavelength tuning and stable single mode operations.
Observation of thermoacoustic shock waves in a resonance tube.
Biwa, Tetsushi; Sobata, Kazuya; Otake, Shota; Yazaki, Taichi
2014-09-01
This paper reports thermally induced shock waves observed in an acoustic resonance tube. Self-sustained oscillations of a gas column were created by imposing an axial temperature gradient on the short stack of plates installed in the resonance tube filled with air at atmospheric pressure. The tube length and axial position of the stack were examined so as to make the acoustic amplitude of the gas oscillations maximum. The periodic shock wave was observed when the acoustic pressure amplitude reached 8.3 kPa at the fundamental frequency. Measurements of the acoustic intensity show that the energy absorption in the stack region with the temperature gradient tends to prevent the nonlinear excitation of harmonic oscillations, which explains why the shock waves had been unfavorable in the resonance tube thermoacoustic systems.
Resonant acoustic transducer system for a well drilling string
Nardi, Anthony P.
1981-01-01
For use in transmitting acoustic waves propated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting a resonant operation in the desired low frequency range.
A sound absorptive element comprising an acoustic resonance nanofibrous membrane.
Kalinova, Klara
2015-01-01
As absorption of sound of lower frequencies is quite problematic with fibrous material made up of coarser fibers, development of highly efficient sound absorption material is called for. This is why this work deals with the development of new high sound absorption material. To absorb the low frequencies, especially the structures based on resonance principle of nanofibrous layers are used, when through resonance of some elements the acoustic energy is transferred into thermal energy. The goal of the invention is achieved by a sound absorbing means which contains resonance membrane formed by a layer of polymeric nanofibers, which is attached to a frame. For production of nanofibrous membranes, the cord electrospinning was used. The resonance membrane was then, upon impact of sound waves of low frequency, brought into forced vibrations, whereby the kinetic energy of the membrane was converted into thermal energy by friction of individual nanofibers, by the friction of the membrane with ambient air and possibly with other layers of material arranged in its proximity, and some of the energy was also transmitted to the frame, through which the vibrations of the resonance membrane were damped. The density and shape of the mesh of frame formations determine the resonance frequency of the acoustic means. The goal of the invention is therefore to eliminate or at least reduce the disadvantages of the present state of the art and to propose sound absorbing means that would be capable of absorbing, with good results sounds in as broadest frequency range as possible. Here, we also discussed some patents relevant to the topic.
Coherence-Resonance Chimeras in a Network of Excitable Elements
NASA Astrophysics Data System (ADS)
Semenova, Nadezhda; Zakharova, Anna; Anishchenko, Vadim; Schöll, Eckehard
2016-07-01
We demonstrate that chimera behavior can be observed in nonlocally coupled networks of excitable systems in the presence of noise. This phenomenon is distinct from classical chimeras, which occur in deterministic oscillatory systems, and it combines temporal features of coherence resonance, i.e., the constructive role of noise, and spatial properties of chimera states, i.e., the coexistence of spatially coherent and incoherent domains in a network of identical elements. Coherence-resonance chimeras are associated with alternating switching of the location of coherent and incoherent domains, which might be relevant in neuronal networks.
Coherence-Resonance Chimeras in a Network of Excitable Elements.
Semenova, Nadezhda; Zakharova, Anna; Anishchenko, Vadim; Schöll, Eckehard
2016-07-01
We demonstrate that chimera behavior can be observed in nonlocally coupled networks of excitable systems in the presence of noise. This phenomenon is distinct from classical chimeras, which occur in deterministic oscillatory systems, and it combines temporal features of coherence resonance, i.e., the constructive role of noise, and spatial properties of chimera states, i.e., the coexistence of spatially coherent and incoherent domains in a network of identical elements. Coherence-resonance chimeras are associated with alternating switching of the location of coherent and incoherent domains, which might be relevant in neuronal networks.
Emerging Beam Resonances in Atom Diffraction from a Reflection Grating
Zhao, Bum Suk; Meijer, Gerard; Schoellkopf, Wieland
2010-06-18
We report on the observation of emerging beam resonances, well known as Rayleigh-Wood anomalies and threshold resonances in photon and electron diffraction, respectively, in an atom-optical diffraction experiment. Diffraction of He atom beams reflected from a blazed ruled grating at grazing incidence has been investigated. The total reflectivity of the grating as well as the intensities of the diffracted beams reveal anomalies at the Rayleigh angles of incidence, i.e., when another diffracted beam emerges parallel to the grating surface. The observed anomalies are discussed in terms of the classical wave-optical model of Rayleigh and Fano.
Spin-Isospin Resonances: A Self-Consistent Covariant Description
Liang Haozhao; Nguyen Van Giai; Meng Jie
2008-09-19
For the first time a fully self-consistent charge-exchange relativistic RPA based on the relativistic Hartree-Fock (RHF) approach is established. The self-consistency is verified by the so-called isobaric analog state (IAS) check. The excitation properties and the nonenergy weighted sum rules of two important charge-exchange excitation modes, the Gamow-Teller resonance (GTR) and the spin-dipole resonance (SDR), are well reproduced in the doubly magic nuclei {sup 48}Ca, {sup 90}Zr and {sup 208}Pb without readjustment of the particle-hole residual interaction. The dominant contribution of the exchange diagrams is demonstrated.
Cranial and spinal magnetic resonance imaging: A guide and atlas
Daniels, D.L.; Haughton, V.M.
1987-01-01
This atlas provides a clinical guide to interpreting cranial and spinal magnetic resonance images. The book includes coverage of the cerebrum, temporal bone, and cervical, thoracic, and lumbar spine, with more than 400 scan images depicting both normal anatomy and pathologic findings. Introductory chapters review the practical physics of magnetic resonance (MR) imaging, offer guidelines for interpreting cranial MR scans, and provide coverage of each anatomic region of the cranium and spine. For each region, scans accompanied by captions, show normal anatomic sections matched with MR images. These are followed by MR scans depicting various disease states.
Resonant acoustic transducer system for a well drilling string
Kent, William H.; Mitchell, Peter G.
1981-01-01
For use in transmitting acoustic waves propagated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting resonant operation in the desired low frequency range.
A millimeter wavelength radiation source using a dual grating resonator
Killoran, J.H.; Hacker, F.L.; Walsh, J.E. . Dept. of Physics)
1994-10-01
A novel means of producing coherent radiation by passing an electron through a dual-grating resonator is presented. The observed radiation is in accordance with the Smith-Purcell dispersion relation for a single grating. Feedback is provided by a second grating. Experiments carried out at beam energies from 30--55 KeV produced radiation at wavelengths from 6 to 0.75 mm. Power measurements were used to clarify the grating-beam interaction. Indications are that operation could be easily extended to shorter wavelengths to provide an inexpensive and compact radiation source in the far-infrared.
Spatiotemporal optical pulse transformation by a resonant diffraction grating
Golovastikov, N. V.; Bykov, D. A. Doskolovich, L. L. Soifer, V. A.
2015-11-15
The diffraction of a spatiotemporal optical pulse by a resonant diffraction grating is considered. The pulse diffraction is described in terms of the signal (the spatiotemporal incident pulse envelope) passage through a linear system. An analytic approximation in the form of a rational function of two variables corresponding to the angular and spatial frequencies has been obtained for the transfer function of the system. A hyperbolic partial differential equation describing the general form of the incident pulse envelope transformation upon diffraction by a resonant diffraction grating has been derived from the transfer function. A solution of this equation has been obtained for the case of normal incidence of a pulse with a central frequency lying near the guided-mode resonance of a diffraction structure. The presented results of numerical simulations of pulse diffraction by a resonant grating show profound changes in the pulse envelope shape that closely correspond to the proposed theoretical description. The results of the paper can be applied in creating new devices for optical pulse shape transformation, in optical information processing problems, and analog optical computations.
A capacitive ultrasonic transducer based on parametric resonance
NASA Astrophysics Data System (ADS)
Surappa, Sushruta; Satir, Sarp; Levent Degertekin, F.
2017-07-01
A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of fo. When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2fo with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at fo frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.
A capacitive ultrasonic transducer based on parametric resonance.
Surappa, Sushruta; Satir, Sarp; Levent Degertekin, F
2017-07-24
A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of fo. When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2fo with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at fo frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.
NASA Astrophysics Data System (ADS)
Herrera, Sheryl Lyn
Covert stroke (CS) comprises lesions in the brain often associated by risk factors such as a diet high in fat, salt, cholesterol and sugar (HFSCS). Developing a rodent model for CS incorporating these characteristics is useful for developing and testing interventions. The purpose of this thesis was to determine if magnetic resonance (MR) can detect brain abnormalities to confirm this model will have the desired anatomical effects. Ex vivo MR showed brain abnormalities for rats with the induced lesions and fed the HFSCS diet. Spectra acquired on the fixed livers had an average percent area under the fat peak relative to the water peak of (20+/-4)% for HFSCS and (2+/-2)% for control. In vivo MR images had significant differences between surgeries to induce the lesions (p=0.04). These results show that applying MR identified abnormalities in the rat model and therefore is important in the development of this CS rodent model.
Effect of internal resistance of a Helmholtz resonator on acoustic energy reduction in enclosures.
Yu, Ganghua; Li, Deyu; Cheng, Li
2008-12-01
The effect of internal resistance of a Helmholtz resonator on acoustic energy reduction in an enclosure and the multimodal coupling-based Helmholtz resonator design are investigated. Using the analytical solution of a resonator-enclosure interaction model, an energy reduction index is defined in a frequency band to optimize the resonator resistance. The dual process of energy dissipation and radiation of the resonator is quantified. Optimal resistance of the resonator and its physical effect on the resonator-enclosure interaction are numerically evaluated and categorized in terms of frequency bandwidths. Predictions on the resonator performance are confirmed by experiments. Comparisons with existing models based on different optimization criteria are also performed. It is shown that the proposed model serves as an effective design tool to determine the internal resistance of the resonator in order to achieve sound reduction in the frequency band enclosing acoustic resonances.
León Aveleyra, G; Holmes, C A; Milburn, G J
2014-06-01
Optomechanical systems are based on the nonlinear coupling between the electromagnetic (EM) field in a resonator and one or more bulk mechanical resonators such that the frequency of the EM field resonator depends on the displacement coordinates of each of the mechanical resonators. In this paper we consider the case of multiple mechanical resonators interacting with a common field for which the frequency of the EM resonance is tuned to depend quadratically (to lowest order) on the displacement of the resonators. By using the method of amplitude equations around a critical point, it is shown that groups of near-identical bulk mechanical resonators with low driving fail to synchronize unless their natural frequencies are identical, in which case the resulting system can exhibit multistability.
Pyroshock simulation for satellite components using a tunable resonant fixture
NASA Astrophysics Data System (ADS)
Davie, N. T.; Bateman, V. I.
Aerospace components are often subjected to pyroshock events during flight and deployment, and must be qualified to this frequently severe environment. Laboratory simulation of pyroshock using a mechanically excited resonant fixture, has gained favor at Sandia for testing small (less than 8 inch cube) satellite and weapon components. With this method, each different shock environment required a different resonant fixture that was designed such that it's response reached the environment. A new test method has been developed which eliminates the need to have a different resonant fixture for each test requirement. This is accomplished by means of a tunable resonant fixture that has a response which is adjustable over a wide frequency range. The adjustment of the fixture's response is done in a simple and deterministic way. This report covers the first phase of this research, which includes design conception through fabrication and evaluation of hardware capable of testing components with up to a 10 inch x 10 inch base. This method will ultimately allow the testing of much larger items, perhaps as large as entire small satellites.
Pyroshock simulation for satellite components using a tunable resonant fixture
Davie, N.T.; Bateman, V.I.
1992-12-31
Aerospace components are often subjected to pyroshock events during flight and deployment, and must be qualified to this frequently severe environment. Laboratory simulation of pyroshock using a mechanically excited resonant fixture, has gained favor at Sandia for testing small (<8 inch cube) satellite and weapon components. With this method, each different shock environment required a different resonant fixture that was designed such that it`s response retched the environment A new test method has been developed which eliminates the need to have a different resonant fixture for each test requirement This is accomplished by means of a tunable resonant fixture that has a response which is adjustable over a wide frequency range. The adjustment of the fixture`s response is done in a simple and deterministic way. This report covers the first phase of this research, which includes design conception through fabrication and evaluation of hardware capable of testing components with up to a 10 inch {times} 10 inch base. This method will ultimately allow the testing of much larger items, perhaps as large as entire small satellites.
Pyroshock simulation for satellite components using a tunable resonant fixture
Davie, N.T.; Bateman, V.I.
1992-01-01
Aerospace components are often subjected to pyroshock events during flight and deployment, and must be qualified to this frequently severe environment. Laboratory simulation of pyroshock using a mechanically excited resonant fixture, has gained favor at Sandia for testing small (<8 inch cube) satellite and weapon components. With this method, each different shock environment required a different resonant fixture that was designed such that it's response retched the environment A new test method has been developed which eliminates the need to have a different resonant fixture for each test requirement This is accomplished by means of a tunable resonant fixture that has a response which is adjustable over a wide frequency range. The adjustment of the fixture's response is done in a simple and deterministic way. This report covers the first phase of this research, which includes design conception through fabrication and evaluation of hardware capable of testing components with up to a 10 inch [times] 10 inch base. This method will ultimately allow the testing of much larger items, perhaps as large as entire small satellites.
Single Molecule Magnetic Force Detection with a Carbon Nanotube Resonator
NASA Astrophysics Data System (ADS)
Willick, Kyle; Walker, Sean; Baugh, Jonathan
2015-03-01
Single molecule magnets (SMMs) sit at the boundary between macroscopic magnetic behaviour and quantum phenomena. Detecting the magnetic moment of an individual SMM would allow exploration of this boundary, and could enable technological applications based on SMMs such as quantum information processing. Detection of these magnetic moments remains an experimental challenge, particularly at the time scales of relaxation and decoherence. We present a technique for sensitive magnetic force detection that should permit such measurements. A suspended carbon nanotube (CNT) mechanical resonator is combined with a magnetic field gradient generated by a ferromagnetic gate electrode, which couples the magnetic moment of a nanomagnet to the resonant motion of the CNT. Numerical calculations of the mechanical resonance show that resonant frequency shifts on the order of a few kHz arise due to single Bohr magneton changes in magnetic moment. A signal-to-noise analysis based on thermomechanical noise shows that magnetic switching at the level of a Bohr magneton can be measured in a single shot on timescales as short as 10 μs. This sensitivity should enable studies of the spin dynamics of an isolated SMM, within the spin relaxation timescales for many available SMMs. Supported by NSERC.
Cyclotron Resonance of Electrons Trapped in a Microwave Cavity
ERIC Educational Resources Information Center
Elmore, W. C.
1975-01-01
Describes an experiment in which the free-electron cyclotron resonance of electrons trapped in a microwave cavity by a Penning trap is observed. The experiment constitutes an attractive alternative to one of the Gardner-Purcell variety. (Author/GS)
Nonlinear Dynamics of a Helicopter Model in Ground Resonance
NASA Technical Reports Server (NTRS)
Tang, D. M.; Dowell, E. H.
1985-01-01
An approximate theoretical method is presented which determined the limit cycle behavior of a helicopter model which has one or two nonlinear dampers. The relationship during unstable ground resonance oscillations between lagging motion of the blades and fuselage motion is discussed. An experiment was carried out on using a helicopter scale model. The experimental results agree with those of the theoretical analysis.
Analytical investigation into the resonance frequencies of a curling probe
NASA Astrophysics Data System (ADS)
Arshadi, Ali; Brinkmann, Ralf Peter
2016-08-01
The term ‘active plasma resonance spectroscopy’ (APRS) denotes a class of closely related plasma diagnostic methods which utilize the natural ability of plasmas to resonate on or near the electron plasma frequency {ω\\text{pe}} ; an electrical radio frequency signal (in the GHz range) is coupled into the plasma via an antenna or a probe, the spectral response is recorded and a mathematical model is employed to determine plasma parameters such as the plasma density and the electron temperature. The curling probe, recently invented by Liang et al (2011 Appl. Phys. Express 4 066101), is a novel realization of the APRS concept which has many practical advantages. In particular, it can be miniaturized and flatly embedded into the chamber wall, thus allowing the monitoring of plasma processes without contamination nor disturbance. Physically, the curling probe can be understood as a ‘coiled’ form of the hairpin probe (Stenzel 1976 Rev. Sci. Instrum. 47 603). Assuming that the spiralization of the probe has little electrical effect, this paper investigates the characteristcs of a ‘straightened’ curling probe by modeling it as an infinite slot-type resonator that is in direct contact with the plasma. The diffraction of an incident plane wave at the slot is calculated by solving the cold plasma model and Maxwell’s equations simultaneously. The resonance frequencies of the probe are derived and are found to be in good agreement with the numerical results of the probe inventors.
Biofouling Removal and Protein Detection Using a Hypersonic Resonator.
Pan, Shuting; Zhang, Hongxiang; Liu, Wenpeng; Wang, Yanyan; Pang, Wei; Duan, Xuexin
2017-08-25
Nonspecific binding (NSB) is a general issue for surface based biosensors. Various approaches have been developed to prevent or remove the NSBs. However, these approaches either increased the background signals of the sensors or limited to specific transducers interface. In this work, we developed a hydrodynamic approach to selectively remove the NSBs using a microfabricated hypersonic resonator with 2.5 gigahertz (GHz) resonant frequency. The high frequency device facilitates generation of multiple controlled microvortexes which then create cleaning forces at the solid-liquid interfaces. The competitive adhesive and cleaning forces have been investigated using the finite element method (FEM) simulation, identifying the feasibility of the vortex-induced NSB removal. NSB proteins have been selectively removed experimentally both on the surface of the resonator and on other substrates which contact the vortexes. Thus, the developed hydrodynamic approach is believed to be a simple and versatile tool for NSB removal and compatible to many sensor systems. The unique feature of the hypersonic resonator is that it can be used as a gravimetric sensor as well; thus a combined NSB removal and protein detection dual functional biosensor system is developed.
Experimental development of a petal resonator surface coil.
Rodríguez, Alfredo Odon; Hidalgo, Sandra Silvia; Rojas, Rafael; Barrios, Fernando Alejandro
2005-12-01
A surface coil for MRI was designed and built based on the principles of the petal resonator proposed by Mansfield [J Phys D Appl Phys 21 (1988) 1643]. This resonator coil design was named the petal resonator surface (PERES) coil and is composed of an eight-petal coil array and a central circular coil. A minimum separation of three times the petal coil radius is necessary to significantly decrease the mutual inductance. An analytical function for the PERES Signal-to-noise ratio (SNR) is obtained based on the quasistatic method. Theoretical plots of SNR enhancement yielded 26% and 35% more SNR over the circular coil and phased-array coils. Imaging experiments were first performed using a spectroscopy phantom on a 1.5-T commercial imager. Subsequently, brain images of healthy volunteers were obtained. Clinical MR imager compatibility allows this resonator coil to be used with conventional pulse sequences and imaging protocols. This coil design offers a new alternative to existing surface coils because it significantly increases the SNR.
NASA Astrophysics Data System (ADS)
Cortázar, O. D.; Megía-Macías, A.; Vizcaíno-de-Julián, A.
2013-09-01
Time resolved electron temperature and density measurements during the decay stage in a hydrogen electron cyclotron resonance (ECR) plasma are presented for a resonance and off-resonance magnetic field configurations. The measurements are conducted on a ECR plasma generator excited at 2.45 GHz denominated test-bench for ion-sources plasma studies at ESS Bilbao. The plasma parameters evolution is studied by Langmuir probe diagnostic with synchronized sample technique developed for repetitive pulsed plasmas with a temporal resolution of 200 ns in typical decay processes of about 40 μs. An afterglow transient is clearly observed in the reflected microwave power signal from the plasma. Simultaneously, the electron temperature evolution shows rebounding peaks that may be related to the interplay between density drop and microwave coupling with deep impact on the Electron Energy Distribution Function. The correlation of such structures with the plasma absorbed power and the coupling quality is also reported.
Cortázar, O. D.
2013-09-15
Time resolved electron temperature and density measurements during the decay stage in a hydrogen electron cyclotron resonance (ECR) plasma are presented for a resonance and off-resonance magnetic field configurations. The measurements are conducted on a ECR plasma generator excited at 2.45 GHz denominated test-bench for ion-sources plasma studies at ESS Bilbao. The plasma parameters evolution is studied by Langmuir probe diagnostic with synchronized sample technique developed for repetitive pulsed plasmas with a temporal resolution of 200 ns in typical decay processes of about 40 μs. An afterglow transient is clearly observed in the reflected microwave power signal from the plasma. Simultaneously, the electron temperature evolution shows rebounding peaks that may be related to the interplay between density drop and microwave coupling with deep impact on the Electron Energy Distribution Function. The correlation of such structures with the plasma absorbed power and the coupling quality is also reported.
Cortázar, O D; Megía-Macías, A; Vizcaíno-de-Julián, A
2013-09-01
Time resolved electron temperature and density measurements during the decay stage in a hydrogen electron cyclotron resonance (ECR) plasma are presented for a resonance and off-resonance magnetic field configurations. The measurements are conducted on a ECR plasma generator excited at 2.45 GHz denominated test-bench for ion-sources plasma studies at ESS Bilbao. The plasma parameters evolution is studied by Langmuir probe diagnostic with synchronized sample technique developed for repetitive pulsed plasmas with a temporal resolution of 200 ns in typical decay processes of about 40 μs. An afterglow transient is clearly observed in the reflected microwave power signal from the plasma. Simultaneously, the electron temperature evolution shows rebounding peaks that may be related to the interplay between density drop and microwave coupling with deep impact on the Electron Energy Distribution Function. The correlation of such structures with the plasma absorbed power and the coupling quality is also reported.
A multiple degree of freedom electromechanical Helmholtz resonator.
Liu, Fei; Horowitz, Stephen; Nishida, Toshikazu; Cattafesta, Louis; Sheplak, Mark
2007-07-01
The development of a tunable, multiple degree of freedom (MDOF) electromechanical Helmholtz resonator (EMHR) is presented. An EMHR consists of an orifice, backing cavity, and a compliant piezoelectric composite diaphragm. Electromechanical tuning of the acoustic impedance is achieved via passive electrical networks shunted across the piezoceramic. For resistive and capacitive loads, the EMHR is a 2DOF system possessing one acoustic and one mechanical DOF. When inductive ladder networks are employed, multiple electrical DOF are added. The dynamics of the multi-energy domain system are modeled using lumped elements and are represented in an equivalent electrical circuit, which is used to analyze the tunable acoustic input impedance of the EMHR. The two-microphone method is used to measure the acoustic impedance of two EMHR designs with a variety of resistive, capacitive, and inductive shunts. For the first design, the data demonstrate that the tuning range of the second resonant frequency for an EMHR with non-inductive shunts is limited by short- and open-circuit conditions, while an inductive shunt results in a 3DOF system possessing an enhanced tuning range. The second design achieves stronger coupling between the Helmholtz resonator and the piezoelectric backplate, and both resonant frequencies can be tuned with different non-inductive loads.
NASA Astrophysics Data System (ADS)
Cheng, Tinghai; Li, Hengyu; He, Meng; Zhao, Hongwei; Lu, Xiaohui; Gao, Haibo
2017-03-01
A resonant/off-resonant hybrid excitation of a piezoelectric stick–slip actuator is proposed in this paper. It is accomplished by a resonant sinusoidal friction regulation wave (RSFR-wave) and an off-resonant saw-tooth wave (ORST-wave). The RSFR-wave is applied to the rapid deformation stage of the ORST-wave. In this stage, the first-order longitudinal vibration mode of the stator can be obtained. By this longitudinal vibration mode, the kinetic friction between the slider and frictional rod is obviously decreased utilizing ultrasonic friction reduction. The backward displacement is remarkably restrained. The high velocity, large mass of load and smooth displacement are achieved. The operation principle of hybrid excitation was discussed in detail, and a prototype was simulated, designed, and fabricated. A series of experiments were carried out and the results indicate that the step efficiency under the saw-tooth excitation and resonant/off-resonant hybrid excitation can realize 36.9% and 91.2%, respectively. The output velocity is increased by 147.23% relative to saw-tooth excitation. The minimum input power and the minimum driving voltage are decreased by 89.56% and 58.33%, respectively. Besides, the maximum mass of load capacity is 2.88 times that of saw-tooth excitation. The driving capacity of the actuator is increased by 466.13%.
Gap Plasmon Resonance in a Suspended Plasmonic Nanowire Coupled to a Metallic Substrate.
Miyata, Masashi; Holsteen, Aaron; Nagasaki, Yusuke; Brongersma, Mark L; Takahara, Junichi
2015-08-12
We present an experimental demonstration of nanoscale gap plasmon resonators that consist of an individual suspended plasmonic nanowire (NW) over a metallic substrate. Our study demonstrates that the NW supports strong gap plasmon resonances of various gap sizes including single-nanometer-scale gaps. The obtained resonance features agree well with intuitive resonance models for near- and far-field regimes. We also illustrate that our suspended NW geometry is capable of constructing plasmonic coupled systems dominated by quasi-electrostatics.
Decay Times and Quality Factors for a Resonance Apparatus
ERIC Educational Resources Information Center
Stephens, Heather; Tam, Austin; Moloney, Michael
2011-01-01
The commercial resonance demonstration apparatus shown in Fig. 1 exhibits curious behavior. It consists of three pairs of slender spring-steel rods attached to a horizontal bar. When one of the rods is pulled aside and released, the rod of corresponding length is excited into visible motion, but the other rods remain apparently stationary. This…
Collisional Properties of a Polarized Fermi Gas with Resonant Interactions
Bruun, G. M.; Recati, A.; Stringari, S.; Pethick, C. J.; Smith, H.
2008-06-20
Highly polarized mixtures of atomic Fermi gases constitute a novel Fermi liquid. We demonstrate how information on thermodynamic properties may be used to calculate quasiparticle scattering amplitudes even when the interaction is resonant and apply the results to evaluate the damping of the spin dipole mode. We estimate that under current experimental conditions the mode would be intermediate between the hydrodynamic and collisionless limits.
Electrically tunable Dicke effect in a double-ring resonator
Cetin, A. E.; Muestecaplioglu, Oe. E.
2010-04-15
We study the finite-element method analysis of the Dicke effect using numerical simulations in an all-optical system of an optical waveguide side-coupled to two interacting ring resonators in a liquid crystal environment. The system is shown to exhibit all the signatures of the Dicke effect under active and reversible control by an applied voltage.
Nonlinear resonances of a single-wall carbon nanotube cantilever
NASA Astrophysics Data System (ADS)
Kim, I. K.; Lee, S. I.
2015-03-01
The dynamics of an electrostatically actuated carbon nanotube (CNT) cantilever are discussed by theoretical and numerical approaches. Electrostatic and intermolecular forces between the single-walled CNT and a graphene electrode are considered. The CNT cantilever is analyzed by the Euler-Bernoulli beam theory, including its geometric and inertial nonlinearities, and a one-mode projection based on the Galerkin approximation and numerical integration. Static pull-in and pull-out behaviors are adequately represented by an asymmetric two-well potential with the total potential energy consisting of the CNT elastic energy, electrostatic energy, and the Lennard-Jones potential energy. Nonlinear dynamics of the cantilever are simulated under DC and AC voltage excitations and examined in the frequency and time domains. Under AC-only excitation, a superharmonic resonance of order 2 occurs near half of the primary frequency. Under both DC and AC loads, the cantilever exhibits linear and nonlinear primary and secondary resonances depending on the strength of the excitation voltages. In addition, the cantilever has dynamic instabilities such as periodic or chaotic tapping motions, with a variation of excitation frequency at the resonance branches. High electrostatic excitation leads to complex nonlinear responses such as softening, multiple stability changes at saddle nodes, or period-doubling bifurcation points in the primary and secondary resonance branches.
Decay Times and Quality Factors for a Resonance Apparatus
ERIC Educational Resources Information Center
Stephens, Heather; Tam, Austin; Moloney, Michael
2011-01-01
The commercial resonance demonstration apparatus shown in Fig. 1 exhibits curious behavior. It consists of three pairs of slender spring-steel rods attached to a horizontal bar. When one of the rods is pulled aside and released, the rod of corresponding length is excited into visible motion, but the other rods remain apparently stationary. This…
A few words about resonances in the electroweak effective Lagrangian
Rosell, Ignasi; Sanz-Cillero, Juan José
2016-01-22
Contrary to a widely spread believe, we have demonstrated that strongly coupled electroweak models including both a light Higgs-like boson and massive spin-1 resonances are not in conflict with experimental constraints on the oblique S and T parameters. We use an effective Lagrangian implementing the chiral symmetry breaking SU (2){sub L} ⊗ SU (2){sub R} → SU (2){sub L+R} that contains the Standard Model gauge bosons coupled to the electroweak Goldstones, one Higgs-like scalar state h with mass m{sub h} = 126 GeV and the lightest vector and axial-vector resonance multiplets V and A. We have considered the one-loop calculation of S and T in order to study the viability of these strongly-coupled scenarios, being short-distance constraints and dispersive relations the main ingredients of the calculation. Once we have constrained the resonance parameters, we do a first approach to the determination of the low energy constants of the electroweak effective theory at low energies (without resonances). We show this determination in the case of the purely Higgsless bosonic Lagrangian.
Resonator design for a visible wavelength free-electron laser (*)
Bhowmik, A.; Lordi, N. . Rocketdyne Div.); Ben-Zvi, I.; Gallardo, J. )
1990-01-01
Design requirements for a visible wavelength free-electron laser being developed at the Accelerator Test Facility at Brookhaven National Laboratory are presented along with predictions of laser performance from 3-D numerical simulations. The design and construction of the optical resonator, its alignment and control systems are also described. 15 refs., 8 figs., 4 tabs.
Magnetic Resonance Fiber Tracking in a Neonate with Hemimegalencephaly.
Re, Thomas J; Scarciolla, Laura; Takahashi, Emi; Specchio, Nicola; Bernardi, Bruno; Longo, Daniela
2015-01-01
A magnetic resonance diffusion fiber tracking study in neonate diagnosed with left hemisphere hemimegalencephaly is presented. Despite diffuse morphologic deformities identified in conventional imaging, all major pathways were identifiable bilaterally with minor aberrations in vicinity of morphologic lesions. Copyright © 2015 by the American Society of Neuroimaging.
Spin resonance and spin fluctuations in a quantum wire
NASA Astrophysics Data System (ADS)
Pokrovsky, V. L.
2017-02-01
This is a review of theoretical works on spin resonance in a quantum wire associated with the spin-orbit interaction. We demonstrate that the spin-orbit induced internal "magnetic field" leads to a narrow spin-flip resonance at low temperatures in the absence of an applied magnetic field. An applied dc magnetic field perpendicular to and small compared with the spin-orbit field enhances the resonance absorption by several orders of magnitude. The component of applied field parallel to the spin-orbit field separates the resonance frequencies of right and left movers and enables a linearly polarized ac electric field to produce a dynamic magnetization as well as electric and spin currents. We start with a simple model of noninteracting electrons and then consider the interaction that is not weak in 1d electron system. We show that electron spin resonance in the spin-orbit field persists in the Luttinger liquid. The interaction produces an additional singularity (cusp) in the spin-flip channel associated with the plasma oscillation. As it was shown earlier by Starykh and his coworkers, the interacting 1d electron system in the external field with sufficiently large parallel component becomes unstable with respect to the appearance of a spin-density wave. This instability suppresses the spin resonance. The observation of the electron spin resonance in a thin wires requires low temperature and high intensity of electromagnetic field in the terahertz diapason. The experiment satisfying these two requirements is possible but rather difficult. An alternative approach that does not require strong ac field is to study two-time correlations of the total spin of the wire with an optical method developed by Crooker and coworkers. We developed theory of such correlations. We prove that the correlation of the total spin component parallel to the internal magnetic field is dominant in systems with the developed spin-density waves but it vanishes in Luttinger liquid. Thus, the
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.
Interpreting a 750 GeV diphoton resonance
NASA Astrophysics Data System (ADS)
Gupta, Rick S.; Jäger, Sebastian; Kats, Yevgeny; Perez, Gilad; Stamou, Emmanuel
2016-07-01
We discuss the implications of the significant excesses in the diphoton final state observed by the LHC experiments ATLAS and CMS around a diphoton invariant mass of 750 GeV. The interpretation of the excess as a spin-zero s-channel resonance implies model-independent lower bounds on both its branching ratio and its coupling to photons, which stringently constrain dynamical models. We consider both the case where the excess is described by a narrow and a broad resonance. We also obtain model-independent constraints on the allowed couplings and branching fractions to final states other than diphotons, by including the interplay with 8 TeV searches. These results can guide attempts to construct viable dynamical models of the resonance. Turning to specific models, our findings suggest that the anomaly cannot be accounted for by the presence of only an additional singlet or doublet spin-zero field and the Standard Model degrees of freedom; this includes all two-Higgs-doublet models. Likewise, heavy scalars in the MSSM cannot explain the excess if stability of the electroweak vacuum is required, at least in a leading-order analysis. If we assume that the resonance is broad we find that it is challenging to find a weakly coupled explanation. However, we provide an existence proof in the form of a model with vectorlike quarks with large electric charge that is perturbative up to the 100 TeV scale. For the narrow-resonance case a similar model can be perturbative up to high scales also with smaller charges. We also find that, in their simplest form, dilaton models cannot explain the size of the excess. Some implications for flavor physics are briefly discussed.
A Scalable Framework For Segmenting Magnetic Resonance Images
Hore, Prodip; Goldgof, Dmitry B.; Gu, Yuhua; Maudsley, Andrew A.; Darkazanli, Ammar
2009-01-01
A fast, accurate and fully automatic method of segmenting magnetic resonance images of the human brain is introduced. The approach scales well allowing fast segmentations of fine resolution images. The approach is based on modifications of the soft clustering algorithm, fuzzy c-means, that enable it to scale to large data sets. Two types of modifications to create incremental versions of fuzzy c-means are discussed. They are much faster when compared to fuzzy c-means for medium to extremely large data sets because they work on successive subsets of the data. They are comparable in quality to application of fuzzy c-means to all of the data. The clustering algorithms coupled with inhomogeneity correction and smoothing are used to create a framework for automatically segmenting magnetic resonance images of the human brain. The framework is applied to a set of normal human brain volumes acquired from different magnetic resonance scanners using different head coils, acquisition parameters and field strengths. Results are compared to those from two widely used magnetic resonance image segmentation programs, Statistical Parametric Mapping and the FMRIB Software Library (FSL). The results are comparable to FSL while providing significant speed-up and better scalability to larger volumes of data. PMID:20046893
Towards a comprehensive model for a resonant nanoelectromechanical system
NASA Astrophysics Data System (ADS)
Calvert, S. L.; Shen, Y.; Sabater, A. B.; Mohammadi, S.; Rhoads, J. F.
2015-09-01
The mass production and very large scale integration (VLSI) of micro/nanoelectromechanical systems (M/NEMS) requires the development and use of accurate models and simulations, which are capable of rapidly evaluating potential designs. Because of the large range of applications that have been proposed for M/NEMS, the most useful models are those that can accurately capture a system’s response under widely varying input and operating conditions. This allows the M/NEMS devices to be treated as well understood circuit components in simulation contexts. It is towards this end that a first-principles based model is proposed for a resonant nanosystem inclusive of an electrostatically-actuated fixed-fixed beam resonator, test equipment and system parasitics. By encoding the algebraic and differential equations which describe the system into circuit components using Verilog-A, an experimental test setup was simulated using Spectre and subsequently compared to experimental results for qualitative validation of the model. The simulation was then used to investigate the behavior of a representative device for a basic input configuration that more closely represents a final-use scenario for the nanoresonator. Discrepancies between the commonly-employed experimental methodology and the practical final-use scenario are discussed and used as a platform to encourage the development of improved experimental methodologies, while also emphasizing the need for robust and accurate system-level models.
NASA Astrophysics Data System (ADS)
Son, Hyeok Woo; Cho, Young Ki; Kim, Byung Mun; Back, Hyun Man; Yoo, Hyoungsuk
2016-04-01
A new radio-frequency (RF) resonator for Nuclear Magnetic Resonance (NMR) imaging at clinical magnetic resonance imaging (MRI) systems is proposed in this paper. An approach based on the effects of the properties of metamaterials in split-ring resonators (SRRs) is used to design a new loop resonator with a SRR for NMR imaging. This loop resonator with a SRR is designed for NMR imaging at 3 T MRI systems. The 3D electromagnetic simulation was used to optimize the design of the proposed RF resonator and analyze it's performance at 3 T MRI systems. The proposed RF resonator provides strong penetrating magnetic fields at the center of the human phantom model, approximately 10%, as compared to the traditional loop-type RF resonator used for NMR imaging at clinical MRI systems. We also designed an 8-channel body coil for human-body NMR imaging by using the proposed loop resonator with a SRR. This body coil also produces more homogeneous and highly penetrating magnetic fields into the human phantom model.
A Computational and Experimental Study of Resonators in Three Dimensions
NASA Technical Reports Server (NTRS)
Tam, C. K. W.; Ju, H.; Jones, Michael G.; Watson, Willie R.; Parrott, Tony L.
2009-01-01
In a previous work by the present authors, a computational and experimental investigation of the acoustic properties of two-dimensional slit resonators was carried out. The present paper reports the results of a study extending the previous work to three dimensions. This investigation has two basic objectives. The first is to validate the computed results from direct numerical simulations of the flow and acoustic fields of slit resonators in three dimensions by comparing with experimental measurements in a normal incidence impedance tube. The second objective is to study the flow physics of resonant liners responsible for sound wave dissipation. Extensive comparisons are provided between computed and measured acoustic liner properties with both discrete frequency and broadband sound sources. Good agreements are found over a wide range of frequencies and sound pressure levels. Direct numerical simulation confirms the previous finding in two dimensions that vortex shedding is the dominant dissipation mechanism at high sound pressure intensity. However, it is observed that the behavior of the shed vortices in three dimensions is quite different from those of two dimensions. In three dimensions, the shed vortices tend to evolve into ring (circular in plan form) vortices, even though the slit resonator opening from which the vortices are shed has an aspect ratio of 2.5. Under the excitation of discrete frequency sound, the shed vortices align themselves into two regularly spaced vortex trains moving away from the resonator opening in opposite directions. This is different from the chaotic shedding of vortices found in two-dimensional simulations. The effect of slit aspect ratio at a fixed porosity is briefly studied. For the range of liners considered in this investigation, it is found that the absorption coefficient of a liner increases when the open area of the single slit is subdivided into multiple, smaller slits.
Wang, Y K; Dong, Z G; Zhai, Y
2012-08-01
We numerically investigate the antibonding magnetic resonance in a metamaterial composed of rings and plates, with a particular attention to the influence of broken structural symmetry on the Fano-type transmission spectrum as well as the resonant artificial permeability. From the simulation results, it is obvious that the antibonding magnetic resonance with strong magnetic-dipole coupling is responsible for the Fano-type profile, since an increase of the structural asymmetry extent to reduce the magnetic field confinement in one of the gaps will form, in contrary, a Lorentzian resonance dip. The dual excitation pathways, i.e., electric and magnetic resonances, at destructive interference are the underlying reason of the Fano-type transmission response. Additionally, the structural-asymmetry dependence of the artificial permeability shows that the broken symmetry can strongly modify the effective permeability due to the altering magnetic-dipole interactions. It is found that an anti-resonant curve of permeability versus frequency will be resulted in if significant symmetry-broken structure is introduced.
NASA Astrophysics Data System (ADS)
Pluchon, D.; Huby, N.; Lhermite, H.; Duval, D.; Bêche, B.
2012-08-01
In this paper, we report on the design and the overall realization of micro-resonators based on the development of adequate processes on a UV210 polymer. These micro-optical structures are developed by deep ultraviolet lithography allowing fabrication of nano-structured devices by means of low cost and reproducible processes. Two families of resonant micro-structures shaped on disk and stadium with various sizes are investigated. Structural and optical imaging characterizations have been carried out to ensure their ability to act as resonant integrated micro-structures. At first, scanning electron microscopy and Nomarsky microscopy studies confirm the UV-light process resolution down to 450 nm developed on a UV210 polymer. Then, optical characterizations have been performed as regards intensity and spectral properties of such micro-resonators. Field intensity measurements in visible and infrared ranges have been realized and validate light propagation by evanescent coupling between waveguides and micro-resonators. Finally, spectral analyses on TE modes demonstrate the presence of optical resonances with 1.45 nm and 2.19 nm free spectral range values for respectively disk and stadium micro-structures. The UV210 polymer appears appropriate for the realization of micro-structures requiring a few hundred nanometers gap-scale while maintaining adequate spectral properties for versatile applications in telecommunication and metrology.
A single molecule immunoassay by localized surface plasmon resonance.
Mayer, Kathryn M; Hao, Feng; Lee, Seunghyun; Nordlander, Peter; Hafner, Jason H
2010-06-25
Noble metal nanoparticles exhibit sharp spectral extinction peaks at visible and near-infrared frequencies due to the resonant excitation of their free electrons, termed localized surface plasmon resonance (LSPR). Since the resonant frequency is dependent on the refractive index of the nanoparticle surroundings, LSPR can be the basis for sensing molecular interactions near the nanoparticle surface. However, previous studies have not yet determined whether the LSPR mechanism can reach the ultimate sensing limit: the detection of individual molecules. Here we demonstrate single molecule LSPR detection by monitoring antibody-antigen unbinding events through the scattering spectra of individual gold bipyramids. Both experiments and finite element simulations indicate that the unbinding of single antigen molecules results in small, discrete < 0.5 nm blue-shifts of the plasmon resonance. The unbinding rate is consistent with antibody-antigen binding kinetics determined from previous ensemble experiments. According to these results, the effective refractive index of a single protein is approximately 1.54. LSPR sensing could therefore be a powerful addition to the current toolbox of single molecule detection methods since it probes interactions on long timescales and under relatively natural conditions.
Acoustic resonance scattering from a submerged anisotropic sphere
NASA Astrophysics Data System (ADS)
Hasheminejad, S. M.; Maleki, M.
2008-03-01
The resonance scattering theory (RST) is applied to the problem of sound scattering from an elastic transversely isotropic solid sphere suspended in an ideal acoustic fluid medium. The normal mode expansion technique in conjunction with the Frobenius power series solution method is utilized to deal with the material anisotropy. The presented model, which degenerates to the simple isotropic solution in the case of very weak anisotropy, is initially employed to study sensitivity of various resonant modes of vibration to perturbations in elements of the stiffness matrix. Employing a rigid background subtraction, the target’s spectrum of resonances is extracted from the relevant modal backscattering form functions and subsequently traced and discussed through Regge pole trajectory plots. Also, the backscattering form function and resonance spectra, along with the dispersion curves for selected transversely isotropic solid spheres with distinct degrees of material anisotropy, are calculated and discussed. The various modes of propagation associated with the Rayleigh, Whispering Gallery, and fluid-borne Scholte-Stoneley surface waves are identified and examined.
Random acoustic metamaterial with a subwavelength dipolar resonance.
Duranteau, Mickaël; Valier-Brasier, Tony; Conoir, Jean-Marc; Wunenburger, Régis
2016-06-01
The effective velocity and attenuation of longitudinal waves through random dispersions of rigid, tungsten-carbide beads in an elastic matrix made of epoxy resin in the range of beads volume fraction 2%-10% are determined experimentally. The multiple scattering model proposed by Luppé, Conoir, and Norris [J. Acoust. Soc. Am. 131(2), 1113-1120 (2012)], which fully takes into account the elastic nature of the matrix and the associated mode conversions, accurately describes the measurements. Theoretical calculations show that the rigid particles display a local, dipolar resonance which shares several features with Minnaert resonance of bubbly liquids and with the dipolar resonance of core-shell particles. Moreover, for the samples under study, the main cause of smoothing of the dipolar resonance of the scatterers and the associated variations of the effective mass density of the dispersions is elastic relaxation, i.e., the finite time required for the shear stresses associated to the translational motion of the scatterers to propagate through the matrix. It is shown that its influence is governed solely by the value of the particle to matrix mass density contrast.
Resonance effect in the allyl cation and anion: a revisit.
Mo, Yirong
2004-08-20
The interest over the magnitude of the conjugation effect in the allyl cation (1) and anion (2) has been revived recently by Barbour and Karty (J. Org. Chem. 2004, 69, 648-654), who derived the resonance energies of 20-22 and 17-18 kcal/mol for 1 and 2, respectively, using an empirical extrapolation approximation. This paper revisits the case by explicitly calculating the Pauling-Wheland resonance energy, which measures the stabilization from the most stable resonance structure to the delocalized energy-minimum state of a conjugated system, using our newly developed block-localized wave function (BLW) method. This BLW method has the geometrical optimization capability. The computations result in adiabatic resonance energies of 37 kcal/mol for 1 and 38 kcal/mol for 2. The significant disagreement between these values and Barbour and Karty's results originates from the neglect of structural and electronic variations in their derivation which are energy costing. Copyright 2004 American Chemical Society
NASA Technical Reports Server (NTRS)
Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)
2006-01-01
The invention discloses a semi-ring Fabry-Perot (SRFP) optical resonator structure comprising a medium including an edge forming a reflective facet and a waveguide within the medium, the waveguide having opposing ends formed by the reflective facet. The performance of the SRFP resonator can be further enhanced by including a Mach-Zehnder interferometer in the waveguide on one side of the gain medium. The optical resonator can be employed in a variety of optical devices. Laser structures using at least one SRFP resonator are disclosed where the resonators are disposed on opposite sides of a gain medium. Other laser structures employing one or more resonators on one side of a gain region are also disclosed.
Stochastic Resonance in a Bistable Squid Loop
1993-08-01
as a possible explanation for the observed periodicities in the recurrences of the Earth’s Ice Ages. The first publication of a modern theory led to... fields . Using a modern, miniature, thin film SQUID, we hope this demonstration will stimulate further research and development of SR in applied
Interpreting the behavior of a quarter-wave transmission line resonator in a magnetized plasma
Gogna, G. S. Turner, M. M.; Karkari, S. K.
2014-12-15
The quarter wave resonator immersed in a strongly magnetized plasma displays two possible resonances occurring either below or above its resonance frequency in vacuum, f{sub o}. This fact was demonstrated in our recent articles [G. S. Gogna and S. K. Karkari, Appl. Phys. Lett. 96, 151503 (2010); S. K. Karkari, G. S. Gogna, D. Boilson, M. M. Turner, and A. Simonin, Contrib. Plasma Phys. 50(9), 903 (2010)], where the experiments were carried out over a limited range of magnetic fields at a constant electron density, n{sub e}. In this paper, we present the observation of dual resonances occurring over the frequency scan and find that n{sub e} calculated by considering the lower resonance frequency is 25%–30% smaller than that calculated using the upper resonance frequency with respect to f{sub o}. At a given magnetic field strength, the resonances tend to shift away from f{sub o} as the background density is increased. The lower resonance tends to saturate when its value approaches electron cyclotron frequency, f{sub ce}. Interpretation of these resonance conditions are revisited by examining the behavior of the resonance frequency response as a function of n{sub e}. A qualitative discussion is presented which highlights the practical application of the hairpin resonator for interpreting n{sub e} in a strongly magnetized plasma.
Non-blinking quantum dot with a plasmonic nanoshell resonator.
Ji, Botao; Giovanelli, Emerson; Habert, Benjamin; Spinicelli, Piernicola; Nasilowski, Michel; Xu, Xiangzhen; Lequeux, Nicolas; Hugonin, Jean-Paul; Marquier, Francois; Greffet, Jean-Jacques; Dubertret, Benoit
2015-02-01
Colloidal semiconductor quantum dots are fluorescent nanocrystals exhibiting exceptional optical properties, but their emission intensity strongly depends on their charging state and local environment. This leads to blinking at the single-particle level or even complete fluorescence quenching, and limits the applications of quantum dots as fluorescent particles. Here, we show that a single quantum dot encapsulated in a silica shell coated with a continuous gold nanoshell provides a system with a stable and Poissonian emission at room temperature that is preserved regardless of drastic changes in the local environment. This novel hybrid quantum dot/silica/gold structure behaves as a plasmonic resonator with a strong Purcell factor, in very good agreement with simulations. The gold nanoshell also acts as a shield that protects the quantum dot fluorescence and enhances its resistance to high-power photoexcitation or high-energy electron beams. This plasmonic fluorescent resonator opens the way to a new family of plasmonic nanoemitters with robust optical properties.
Non-blinking quantum dot with a plasmonic nanoshell resonator
NASA Astrophysics Data System (ADS)
Ji, Botao; Giovanelli, Emerson; Habert, Benjamin; Spinicelli, Piernicola; Nasilowski, Michel; Xu, Xiangzhen; Lequeux, Nicolas; Hugonin, Jean-Paul; Marquier, Francois; Greffet, Jean-Jacques; Dubertret, Benoit
2015-02-01
Colloidal semiconductor quantum dots are fluorescent nanocrystals exhibiting exceptional optical properties, but their emission intensity strongly depends on their charging state and local environment. This leads to blinking at the single-particle level or even complete fluorescence quenching, and limits the applications of quantum dots as fluorescent particles. Here, we show that a single quantum dot encapsulated in a silica shell coated with a continuous gold nanoshell provides a system with a stable and Poissonian emission at room temperature that is preserved regardless of drastic changes in the local environment. This novel hybrid quantum dot/silica/gold structure behaves as a plasmonic resonator with a strong Purcell factor, in very good agreement with simulations. The gold nanoshell also acts as a shield that protects the quantum dot fluorescence and enhances its resistance to high-power photoexcitation or high-energy electron beams. This plasmonic fluorescent resonator opens the way to a new family of plasmonic nanoemitters with robust optical properties.
Band Structure for a Lattice with a Single Resonance
NASA Astrophysics Data System (ADS)
Monsivais, G.; Moshinsky, M.
1998-03-01
We study the band structure of a chain of scatterers that in general cannot be described by means of a potential. In order to describe these kind of systems we have followed the ideas of Wigner who stressed though that an interaction should be described by a R matrix. In particular, we have considered an infinite sequence of scatterers, each one described by means of a R matrix with a single resonance. This study is an extension of a recent paper ( M. Moshinsky and G. Monsivais, J. Phys. G: Nucl. Part. Phys. 23), 573-588, (1997) where we have studied the delay time for a single scatterer using a R matrix. We compare our results with those than appear in the description of some superlattices.
Hadron resonances with a quark core embedded in the continuum
Shimizu, Kiyotaka; Takeuchi, Sachiko; Takizawa, Makoto
2011-05-06
We investigate the excited baryons and mesons which cannot be described in terms of a simple constituent quark model, such as {Lambda}(1405) and X(3872) as a resonance in a coupled channel hadron-hadron (baryon-meson or meson-meson) scattering with a 'bound state embedded in the continuum' (BSEC). For this purpose, we solve the Lippmann-Schwinger equation including a BSEC in the momentum space. This BSEC is introduced by hand, as a state not originated from a simple baryon-meson or meson-meson system. We assume it comes from the three-quark state or quark-anti quark state and show such a picture can describe the {Lambda}(1405) and X(3872) resonances.
Reciprocity Calibration in a Plane Wave Resonator.
1985-12-01
8217 - " ’. ... .-. ..i" - . . - - . --’ ..- B. HISTORY The acoustical reciprocity principle was introduced first in Lord Rayleigh’s ( John William Strutt ) paper on "Some...assistance and a listening ear. I would like to acknowledge Dr. John Fontenalla and Dr. Mary Wintersgill for their help with computer graphics at the...Korman, my thanks for your steadfast friendship when times were difficult, your encouragement, a ready smile, and good advice. To Dr. John Ertel and Lcdr
Production of ultracold molecules via photoassociation through a Feshbach resonance
NASA Astrophysics Data System (ADS)
Pellegrini, Philippe; Gacesa, Marko; Côté, Robin
2007-10-01
We present a theoretical investigation of photoassociation in the vicinity of a Feshbach resonance for the production of ultracold molecules in their lowest vibrational levels. The formation of ultracold molecules is of particular interest for the realization of quantum computing systems or the development of a cold physical chemistry which proposes to control elementary chemical reactions with or without electro-magnetic fields. Photoassociation, which occurs when two colliding atoms absorb a photon to form a molecule in a bound rovibrational level, has been widely used to produce ultracold dimers but the use of a magnetically induced Feshbach resonance enhances dramatically the probability density at short range allowing efficient transitions even for deeply bound levels. We illustrate this effect in both heteronuclear and homonuclear systems.
Quench dynamics of a strongly interacting resonant Bose gas
NASA Astrophysics Data System (ADS)
Yin, Xiao; Radzihovsky, Leo
2015-03-01
We explore the dynamics of a resonant Bose gas following its quench to a strongly interacting regime near a Feshbach resonance. For such deep quenches, we utilize a self-consistent dynamic mean-field approximation and find that after an initial regime of many-body Rabi-like oscillations between the condensate and finite-momentum quasiparticle pairs, at long times, the gas reaches a prethermalized nonequilibrium steady state. We explore the resulting state through its broad stationary momentum distribution function, that exhibits a power-law high momentum tail. We study the associated enhanced depletion, quench-rate dependent excitation energy, Tan's contact, structure function and radio frequency spectroscopy. We find these predictions to be in a qualitative agreement with recent experiments We acknowledge the supported by the NSF through DMR-1001240 on this research.
Analysis of a Non-resonant Ultrasonic Levitation Device
NASA Astrophysics Data System (ADS)
Andrade, Marco A. B.; Pérez, Nicolás; Adamowski, Julio C.
In this study, a non-resonant configuration of ultrasonic levitation device is presented, which is formed by a small diameter ultrasonic transducer and a concave reflector. The influence of different levitator parameters on the levitation performance is investigated by using a numerical model that combines the Gor'kov theory with a matrix method based on the Rayleigh integral. In contrast with traditional acoustic levitators, the non-resonant ultrasonic levitation device allows the separation distance between the transducer and the reflector to be adjusted continually, without requiring the separation distance to be set to a multiple of half-wavelength. It is also demonstrated, both numerically and experimentally, that the levitating particle can be manipulated by maintaining the transducer in a fixed position in space and moving the reflector in respect to the transducer.
Quantum-dot-induced transparency in a nanoscale plasmonic resonator.
Wu, Xiaohua; Gray, Stephen K; Pelton, Matthew
2010-11-08
We investigate the near-field optical coupling between a single semiconductor nanocrystal (quantum dot) and a nanometer-scale plasmonic metal resonator using rigorous electrodynamic simulations. Our calculations show that the quantum dot produces a dip in both the extinction and scattering spectra of the surface-plasmon resonator, with a particularly strong change for the scattering spectrum. A phenomenological coupled-oscillator model is used to fit the calculation results and provide physical insight, revealing the roles of Fano interference and hybridization. The results indicate that it is possible to achieve nearly complete transparency as well as enter the strong-coupling regime for a single quantum dot in the near field of a metal nanostructure.
Higher-order resonances in a Stark decelerator
Meerakker, Sebastiaan Y.T. van de; Bethlem, Hendrick L.; Vanhaecke, Nicolas; Meijer, Gerard
2005-05-15
The motion of polar molecules can be controlled by time-varying inhomogeneous electric fields. In a Stark decelerator, this is exploited to select a fraction of a molecular beam that is accelerated, transported, or decelerated. Phase stability ensures that the selected bunch of molecules is kept together throughout the deceleration process. In this paper an extended description of phase stability in a Stark decelerator is given, including higher-order effects. This analysis predicts a wide variety of resonances that originate from the spatial and temporal periodicity of the electric fields. These resonances are experimentally observed using a beam of OH ({sup 2}{pi}{sub 3/2},v=0,J=3/2) radicals passing through a Stark decelerator.
Superfluidity and phase transitions in a resonant Bose gas
Radzihovsky, Leo; Weichman, Peter B.; Park, Jae I.
2008-10-15
The atomic Bose gas is studied across a Feshbach resonance, mapping out its phase diagram, and computing its thermodynamics and excitation spectra. It is shown that such a degenerate gas admits two distinct atomic and molecular superfluid phases, with the latter distinguished by the absence of atomic off-diagonal long-range order, gapped atomic excitations, and deconfined atomic {pi}-vortices. The properties of the molecular superfluid are explored, and it is shown that across a Feshbach resonance it undergoes a quantum Ising transition to the atomic superfluid, where both atoms and molecules are condensed. In addition to its distinct thermodynamic signatures and deconfined half-vortices, in a trap a molecular superfluid should be identifiable by the absence of an atomic condensate peak and the presence of a molecular one.
Lightning rod resonance of a plasmonic near-field transducer.
Peng, Chubing; Ko, Kaspar D
2017-06-26
We demonstrate the lightning-rod resonance of a lollipop near-field transducer integrated in magnetic writer for heat-assisted magnetic recording by collecting the two-photon excited photoluminescence (TPL) signal when excited by a pulsed femto-second fiber laser tuned to the desired mode resonance. The lollipop transducer consists of a round disk and a protruding peg to take advantage of the lightning-rod effect. It is found that the TPL signal is extremely sensitive to the peg length where even a 3-5 nm deviation from the optimal peg length halves the TPL signal. This method conveniently quantifies the optical performance of an NFT device in situ as a function of geometry with a resolution of better than the light wavelength (λ) divided by 200.
In search for a possible statistical basis of Stochastic Resonance
NASA Astrophysics Data System (ADS)
Bezrukov, Sergey M.; Vodyanoy, Igor
2000-03-01
Stochastic Resonance (SR) is a phenomenon of enhancing the information content at the system output by adding noise to the input signal. Originally, SR was shown in dynamical systems ranging from glaciers to superconducting junctions. Later it was found to occur in non-dynamical systems with and without thresholds. Now a growing number of publications report SR practically everywhere: in meteorology, sociology, finance, psycho-physics, electrophysiology, chemistry, etc. We seek a general statistical mechanism which would capture and, thus, explain the essence of SR independently of the system where it is found. Though, at present, this problem is far from solved, we think that the doubly-stochastic Poisson process approach described here represents a significant step toward such a generalization. Using this approach, we show that, in contrast to the current point of view, an activation barrier is not a necessary prerequisite of a Stochastic Resonator.
Jia, Yanbing; Gu, Huaguang
2015-12-01
The effect of phase noise on the coherence dynamics of a neuronal network composed of FitzHugh-Nagumo (FHN) neurons is investigated. Phase noise can induce dissimilar coherence resonance (CR) effects for different coupling strength regimes. When the coupling strength is small, phase noise can induce double CRs. One corresponds to the average frequency of phase noise, and the other corresponds to the intrinsic firing frequency of the FHN neuron. When the coupling strength is large enough, phase noise can only induce single CR, and the CR corresponds to the intrinsic firing frequency of the FHN neuron. The results show a transition from double CRs to single CR with the increase in the coupling strength. The transition can be well interpreted based on the dynamics of a single neuron stimulated by both phase noise and the coupling current. When the coupling strength is small, the coupling current is weak, and phase noise mainly determines the dynamics of the neuron. Moreover, the phase-noise-induced double CRs in the neuronal network are similar to the phase-noise-induced double CRs in an isolated FHN neuron. When the coupling strength is large enough, the coupling current is strong and plays a key role in the occurrence of the single CR in the network. The results provide a novel phenomenon and may have important implications in understanding the dynamics of neuronal networks.
Tuning the resonance properties of 2D carbon nanotube networks towards a mechanical resonator
NASA Astrophysics Data System (ADS)
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.
EXCITATION OF STRUCTURAL RESONANCE DUE TO A BEARING FAILURE
Leishear, R; David Stefanko, D
2007-04-30
Vibration due to a bearing failure in a pump created significant vibrations in a fifteen foot by fifteen foot by eight feet tall mounting platform due to excitation of resonant frequencies. In this particular application, an 18,000 pound pump was mounted to a structural steel platform. When bearing damage commenced, the platform vibrated with sufficient magnitude that conversations could not be heard within forty feet of the pump. Vibration analysis determined that the frequency of the bearing was coincident to one of the natural frequencies of the pump, which was, in turn, coincident to one of the natural frequencies of the mounting platform. This coincidence of frequencies defines resonance. Resonance creates excessive vibrations when the natural frequency of a structure is coincident to an excitation frequency. In this well documented case, the excitation frequency was related to ball bearing failures. The pump is a forty foot long vertical pump used to mix nuclear waste in 1,300,000 gallon tanks. A 300 horsepower drive motor is mounted to a structural steel platform on top of the tank. The pump hangs down into the tank from above to mix the waste and is inaccessible after installation. Initial awareness of the problem was due to increased noise from the pump. Initial vibration analysis indicated that the vibration levels of the bearing were within the expected range for this type of bearing, and the resonant condition was not obvious. Further analysis consisted of disassembly of the motor to inspect the bearings and extensive vibration monitoring. Vibration data for the bearings was obtained from the manufacturer and compared to measured vibration plots for the pump and mounting platform. Vibration data measured along the length of the pump was available from full scale testing, and vibrations were also measured at the installed pump. One of the axial frequencies of the pump, the platform frequency in the vertical direction, and the ball spin frequency for the
A high frequency resonance gravity gradiometer
NASA Astrophysics Data System (ADS)
Bagaev, S. N.; Bezrukov, L. B.; Kvashnin, N. L.; Krysanov, V. A.; Oreshkin, S. I.; Motylev, A. M.; Popov, S. M.; Rudenko, V. N.; Samoilenko, A. A.; Skvortsov, M. N.; Yudin, I. S.
2014-06-01
A new setup OGRAN—the large scale opto-acoustical gravitational detector is described. As distinguished from known gravitational bar detectors it uses the optical interferometrical readout for registering weak variations of gravity gradient at the kilohetz frequency region. At room temperature, its sensitivity is limited only by the bar Brownian noise at the bandwidth close to 100 Hz. It is destined for a search for rare events—gravitational pulses coincident with signals of neutrino scintillator (BUST) in the deep underground of Baksan Neutrino Observatory of INR RAS.
A high frequency resonance gravity gradiometer
Bagaev, S. N.; Kvashnin, N. L.; Skvortsov, M. N.; Bezrukov, L. B.; Krysanov, V. A.; Oreshkin, S. I.; Motylev, A. M.; Popov, S. M.; Samoilenko, A. A.; Yudin, I. S.; Rudenko, V. N.
2014-06-15
A new setup OGRAN—the large scale opto-acoustical gravitational detector is described. As distinguished from known gravitational bar detectors it uses the optical interferometrical readout for registering weak variations of gravity gradient at the kilohetz frequency region. At room temperature, its sensitivity is limited only by the bar Brownian noise at the bandwidth close to 100 Hz. It is destined for a search for rare events—gravitational pulses coincident with signals of neutrino scintillator (BUST) in the deep underground of Baksan Neutrino Observatory of INR RAS.
A high frequency resonance gravity gradiometer.
Bagaev, S N; Bezrukov, L B; Kvashnin, N L; Krysanov, V A; Oreshkin, S I; Motylev, A M; Popov, S M; Rudenko, V N; Samoilenko, A A; Skvortsov, M N; Yudin, I S
2014-06-01
A new setup OGRAN--the large scale opto-acoustical gravitational detector is described. As distinguished from known gravitational bar detectors it uses the optical interferometrical readout for registering weak variations of gravity gradient at the kilohetz frequency region. At room temperature, its sensitivity is limited only by the bar Brownian noise at the bandwidth close to 100 Hz. It is destined for a search for rare events--gravitational pulses coincident with signals of neutrino scintillator (BUST) in the deep underground of Baksan Neutrino Observatory of INR RAS.
Ferromagnetic resonance in a dilute suspension of uniaxial superparamagnetic particles
NASA Astrophysics Data System (ADS)
Poperechny, I. S.; Raikher, Yu. L.; Stepanov, V. I.
2017-02-01
A consistent theory of ferromagnetic resonance in a dilute suspension of superparamagnetic particles with uniaxial anisotropy of arbitrary strength is presented. The developed approach is used for studying the high-frequency response of a magnetic fluid at different temperatures. It is shown that in a certain temperature interval the absorption line splits into two components. The width of this interval is essentially dependent on the magnitude of the particle anisotropy.
Implementation of a Biaxial Resonant Fatigue Test Method on a Large Wind Turbine Blade
Snowberg, D.; Dana, S.; Hughes, S.; Berling, P.
2014-09-01
A biaxial resonant test method was utilized to simultaneously fatigue test a wind turbine blade in the flap and edge (lead-lag) direction. Biaxial resonant blade fatigue testing is an accelerated life test method utilizing oscillating masses on the blade; each mass is independently oscillated at the respective flap and edge blade resonant frequency. The flap and edge resonant frequency were not controlled, nor were they constant for this demonstrated test method. This biaxial resonant test method presented surmountable challenges in test setup simulation, control and data processing. Biaxial resonant testing has the potential to complete test projects faster than single-axis testing. The load modulation during a biaxial resonant test may necessitate periodic load application above targets or higher applied test cycles.
Modeling a Large Ring Resonator Gyroscope.
1985-03-30
of Frequency Stability," IEEE Trans. instr. Meas. IM-20, pp. 105-120, 1 971 . 6. Walls, F. INBS, Boulder, C0), private communication . 7. Bilger, H. R...be written as the following summation. 2 2 to WO Wo Wa +wa H ( V2x ) __2t 2 2 m+ n (-)H-= (46)Yim, 2mn w 0 w A numerical example is given in Figures 18
A Wideband Circularly Polarized Pixelated Dielectric Resonator Antenna.
Trinh-Van, Son; Yang, Youngoo; Lee, Kang-Yoon; Hwang, Keum Cheol
2016-08-23
The design of a wideband circularly polarized pixelated dielectric resonator antenna using a real-coded genetic algorithm (GA) is presented for far-field wireless power transfer applications. The antenna consists of a dielectric resonator (DR) which is discretized into 8 × 8 grid DR bars. The real-coded GA is utilized to estimate the optimal heights of the 64 DR bars to realize circular polarization. The proposed antenna is excited by a narrow rectangular slot etched on the ground plane. A prototype of the proposed antenna is fabricated and tested. The measured -10 dB reflection and 3 dB axial ratio bandwidths are 32.32% (2.62-3.63 GHz) and 14.63% (2.85-3.30 GHz), respectively. A measured peak gain of 6.13 dBic is achieved at 3.2 GHz.
Fidelity for kicked atoms with gravity near a quantum resonance
NASA Astrophysics Data System (ADS)
Dubertrand, Rémy; Guarneri, Italo; Wimberger, Sandro
2012-03-01
Kicked atoms under a constant Stark or gravity field are investigated for experimental setups with cold and ultracold atoms. The parametric stability of the quantum dynamics is studied using the fidelity. In the case of a quantum resonance, it is shown that the behavior of the fidelity depends on arithmetic properties of the gravity parameter. Close to a quantum resonance, the long-time asymptotics of the fidelity is studied by means of a pseudoclassical approximation introduced by Fishman [J. Stat. Phys.JSTPBS0022-471510.1023/A:1022176306198 110, 911 (2003)]. The long-time decay of fidelity arises from the tunneling out of pseudoclassical stable islands, and a simple ansatz is proposed which satisfactorily reproduces the main features observed in numerical simulations.
A Faraday effect position sensor for interventional magnetic resonance imaging.
Bock, M; Umathum, R; Sikora, J; Brenner, S; Aguor, E N; Semmler, W
2006-02-21
An optical sensor is presented which determines the position and one degree of orientation within a magnetic resonance tomograph. The sensor utilizes the Faraday effect to measure the local magnetic field, which is modulated by switching additional linear magnetic fields, the gradients. Existing methods for instrument localization during an interventional MR procedure often use electrically conducting structures at the instruments that can heat up excessively during MRI and are thus a significant danger for the patient. The proposed optical Faraday effect position sensor consists of non-magnetic and electrically non-conducting components only so that heating is avoided and the sensor could be applied safely even within the human body. With a non-magnetic prototype set-up, experiments were performed to demonstrate the possibility of measuring both the localization and the orientation in a magnetic resonance tomograph. In a 30 mT m(-1) gradient field, a localization uncertainty of 1.5 cm could be achieved.
A Wideband Circularly Polarized Pixelated Dielectric Resonator Antenna
Trinh-Van, Son; Yang, Youngoo; Lee, Kang-Yoon; Hwang, Keum Cheol
2016-01-01
The design of a wideband circularly polarized pixelated dielectric resonator antenna using a real-coded genetic algorithm (GA) is presented for far-field wireless power transfer applications. The antenna consists of a dielectric resonator (DR) which is discretized into 8 × 8 grid DR bars. The real-coded GA is utilized to estimate the optimal heights of the 64 DR bars to realize circular polarization. The proposed antenna is excited by a narrow rectangular slot etched on the ground plane. A prototype of the proposed antenna is fabricated and tested. The measured −10 dB reflection and 3 dB axial ratio bandwidths are 32.32% (2.62–3.63 GHz) and 14.63% (2.85–3.30 GHz), respectively. A measured peak gain of 6.13 dBic is achieved at 3.2 GHz. PMID:27563897
NASA Astrophysics Data System (ADS)
Teraoka, Iwao; Yao, Haibei; Huiyi Luo, Natalie
2017-06-01
We employed a recently developed whispering gallery mode (WGM) dip sensor made of silica to obtain spectra for many resonance peaks in water and solutions of sucrose at different concentrations and thus having different refractive indices (RI). The apparent Q factor was estimated by fitting each peak profile in the busy resonance spectrum by a Lorentzian or a sum of Lorentzians. A plot of the Q factor as a function the peak height for all the peaks analyzed indicates a straight line with a negative slope as the upper limit, for each of water and the solutions. A coupling model for a resonator and a pair of fiber tapers to feed and pick up light, developed here, supports the presence of the upper limit. We also found that the round-trip attenuation of WGM was greater than the one estimated from light absorption by water, and the difference increased with the concentration of sucrose.
Bubble cloud dynamics in a high-pressure spherical resonator
NASA Astrophysics Data System (ADS)
Anderson, Phillip Andrew
A bubble cloud is a population of bubbles confined to a region within a fluid. Bubble clouds play a large role in a variety of naturally occurring phenomena and man-made applications (e.g., ocean noise, cavitation damage, sonoluminescence, ultrasonic cleaning, drug delivery, lithotripsy). It is important, therefore, to understand the behavior of bubble clouds so that their effects may be enhanced or diminished as desired. This work explores and characterizes the properties of bubble clouds nucleated inside a high-pressure spherical acoustic resonator, in connection with recent interest in acoustic inertial confinement fusion (acoustic ICF). A laser system was developed to repeatably nucleate a cloud of bubbles inside the resonator. The resulting events were then observed, primarily with schlieren imaging methods. Preliminary studies of the bubble cloud dynamics showed the sensitivity of the initial cloud to nucleation parameters including the phase of nucleation, the laser energy, and the acoustic power. After many acoustic cycles, some bubble clouds are observed to evolve into a tight cluster. The formation of these clusters correlates with initial bubble distributions which have a large cloud interaction parameter, β. Cluster dynamics are seen to be largely driven by reconverging shock waves from previous collapses reflected from the resonator's interior surface. Initial expansion of the cluster boundary is on the order of 8 mm/µs and the maximum radius approaches 3 mm. Shock pressures are estimated to be > 10 GPa at a radius of 100 µm using weak shock theory.
A new characterization technique for lossy piezoceramic resonators
NASA Astrophysics Data System (ADS)
Pastore, Robert Allan, Jr.
2000-11-01
Piezoelectricity was discovered by the brothers Curie in 1880. They found that, in certain materials such as zincblende, tourmaline, can sugar, topaz and quartz, mechanical stresses were accompanied by the production of electric surface charges. The piezoelectric effect remained a curiosity until the early 1920s when it was utilized to realize crystal resonators for the stabilization of oscillators, thereby launching the field of frequency control. Piezoelectricity has found many applications as oscillators, filters, and sensors in televisions, cellular phones, radios, ultrasonic imaging, radar and signal processing to name just a few. Most of these applications use high Q single crystal materials such as quartz. These materials can become expensive as the application becomes more specialized. Piezoceramic materials can be used in these applications because it is less expensive, but the Q of the material is low and has very blunt characteristics as compared to quartz. This low Q and blunt resonance is connected to the loss in the material and makes it difficult to characterize the material and to get the maximum performance out of devices made from this material. We have developed a new characterization technique for lossy piezoceramic material based on the use of complex frequencies to stimulate the devices complex resonant point. This technique enables us to find the frequency dependent attenuation constant, and the impedance at the complex resonant point. The material properties of piezoceramics can be described through the use of complex material constants. The solution of the acoustic wave equation leads to complex frequencies as the resonant points for a thickness excited resonator. This leads to the use of complex frequency excitation, which is an exponentially decaying sine wave. The Laplace transform of this type of signal has an imaginary part which is the frequency and the real part which is related to the attenuation of the device. So this type of
Fidelity for kicked atoms with gravity near a quantum resonance.
Dubertrand, Rémy; Guarneri, Italo; Wimberger, Sandro
2012-03-01
Kicked atoms under a constant Stark or gravity field are investigated for experimental setups with cold and ultracold atoms. The parametric stability of the quantum dynamics is studied using the fidelity. In the case of a quantum resonance, it is shown that the behavior of the fidelity depends on arithmetic properties of the gravity parameter. Close to a quantum resonance, the long-time asymptotics of the fidelity is studied by means of a pseudoclassical approximation introduced by Fishman et al. [J. Stat. Phys. 110, 911 (2003)]. The long-time decay of fidelity arises from the tunneling out of pseudoclassical stable islands, and a simple ansatz is proposed which satisfactorily reproduces the main features observed in numerical simulations.
Breathers in a locally resonant granular chain with precompression
Liu, Lifeng; James, Guillaume; Kevrekidis, Panayotis; Vainchtein, Anna
2016-09-01
Here we study a locally resonant granular material in the form of a precompressed Hertzian chain with linear internal resonators. Using an asymptotic reduction, we derive an effective nonlinear Schrödinger (NLS) modulation equation. In turn, this leads us to provide analytical evidence, subsequently corroborated numerically, for the existence of two distinct types of discrete breathers related to acoustic or optical modes: (a) traveling bright breathers with a strain profile exponentially vanishing at infinity and (b) stationary and traveling dark breathers, exponentially localized, time-periodic states mounted on top of a non-vanishing background. Moreover, the stability and bifurcation structure of numerically computed exact stationary dark breathers is also examined. Stationary bright breathers cannot be identified using the NLS equation, which is defocusing at the upper edges of the phonon bands and becomes linear at the lower edge of the optical band.
Breathers in a locally resonant granular chain with precompression
Liu, Lifeng; James, Guillaume; Kevrekidis, Panayotis; ...
2016-09-01
Here we study a locally resonant granular material in the form of a precompressed Hertzian chain with linear internal resonators. Using an asymptotic reduction, we derive an effective nonlinear Schrödinger (NLS) modulation equation. In turn, this leads us to provide analytical evidence, subsequently corroborated numerically, for the existence of two distinct types of discrete breathers related to acoustic or optical modes: (a) traveling bright breathers with a strain profile exponentially vanishing at infinity and (b) stationary and traveling dark breathers, exponentially localized, time-periodic states mounted on top of a non-vanishing background. Moreover, the stability and bifurcation structure of numerically computedmore » exact stationary dark breathers is also examined. Stationary bright breathers cannot be identified using the NLS equation, which is defocusing at the upper edges of the phonon bands and becomes linear at the lower edge of the optical band.« less
Metamaterial split ring resonator as a sensitive mechanical vibration sensor
NASA Astrophysics Data System (ADS)
Sikha Simon, K.; Chakyar, Sreedevi P.; Andrews, Jolly; Joseph V., P.
2017-06-01
This paper introduces a sensitive vibration sensor based on microwave metamaterial Split Ring Resonator (SRR) capable of detecting any ground vibration. The experimental setup consists of single Broad-side Coupled SRR (BCSRR) unit fixed on a cantilever capable of sensitive vibrations. It is arranged between transmitting and receiving probes of a microwave measurement system. The absorption level variations at the resonant frequency due to the displacement from the reference plane of SRR, which is a function of the strength of external mechanical vibration, is analyzed. This portable and cost effective sensor working on a single frequency is observed to be capable of detecting even very weak vibrations. This may find potential applications in the field of tamper-proofing, mining, quarrying and earthquake sensing.
Breathers in a locally resonant granular chain with precompression
Liu, Lifeng; James, Guillaume; Kevrekidis, Panayotis; Vainchtein, Anna
2016-09-01
Here we study a locally resonant granular material in the form of a precompressed Hertzian chain with linear internal resonators. Using an asymptotic reduction, we derive an effective nonlinear Schrödinger (NLS) modulation equation. In turn, this leads us to provide analytical evidence, subsequently corroborated numerically, for the existence of two distinct types of discrete breathers related to acoustic or optical modes: (a) traveling bright breathers with a strain profile exponentially vanishing at infinity and (b) stationary and traveling dark breathers, exponentially localized, time-periodic states mounted on top of a non-vanishing background. Moreover, the stability and bifurcation structure of numerically computed exact stationary dark breathers is also examined. Stationary bright breathers cannot be identified using the NLS equation, which is defocusing at the upper edges of the phonon bands and becomes linear at the lower edge of the optical band.
Characterizing a Superconducting Resonator with Frequency-Compensated Tunable Coupling
NASA Astrophysics Data System (ADS)
Wenner, James; Campbell, B.; Chen, Z.; Chiaro, B.; Dunsworth, A.; Hoi, I.-C.; Kelly, J.; Megrant, A.; Neill, C.; O'Malley, P. J. J.; Quintana, C.; Vainsencher, A.; White, T. C.; Barends, R.; Chen, Y.; Fowler, A. G.; Jeffrey, E.; Mutus, J. Y.; Roushan, P.; Sank, D.; Martinis, John M.
2015-03-01
Deterministic quantum state transfer between devices on different chips requires the ability to transfer quantum states between traveling qubits and fixed logic qubits. Reflections must be minimized to avoid energy loss and phase interference; this requires tunable coupling to an inter-chip line while the two devices are at equal frequencies. To achieve this, we present a 6GHz superconducting coplanar resonator with tunable coupling to a 50 Ohm transmission line. We compensate for the resulting shift in resonator frequency by simultaneously tuning a second SQUID. We further demonstrate the device coherence and the ability both to release a single-frequency shaped pulse into the transmission line and to efficiently capture a shaped pulse, prerequisites for efficient inter-chip deterministic quantum state transfer.
Corralling a Distant Planet with Extreme Resonant Kuiper Belt Objects
NASA Astrophysics Data System (ADS)
Malhotra, Renu; Volk, Kathryn; Wang, Xianyu
2016-06-01
The four longest period Kuiper Belt objects have orbital periods close to integer ratios with each other. A hypothetical planet with an orbital period of ∼17,117 years and a semimajor axis ∼665 au would have N/1 and N/2 period ratios with these four objects. The orbital geometries and dynamics of resonant orbits constrain the orbital plane, the orbital eccentricity, and the mass of such a planet as well as its current location in its orbital path.
Resonance fluorescence from an atom in a squeezed vacuum
NASA Astrophysics Data System (ADS)
Carmichael, H. J.; Lane, A. S.; Walls, D. F.
1987-06-01
The fluorescent spectrum for a two-level atom which is damped by a squeezed vacuum shows striking differences from the spectrum for ordinary resonance fluorescence. For strong coherent driving fields the Mollow triplet depends on the relative phase of the driving field and the squeezed vacuum field. The central peak may have either subnatural linewidth or supernatural linewidth depending on this phase. The mean atomic polarization also shows a phase sensitivity.
Quantum force of tunneling macrospins with a mechanical resonator
NASA Astrophysics Data System (ADS)
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.
A Resonator for Low-Threshold Frequency Conversion
NASA Technical Reports Server (NTRS)
Iltchenko, Vladimir; Matsko, Andrey; Savchenkov, Anatoliy; Maleki, Lute
2004-01-01
A proposed toroidal or disklike dielectric optical resonator (dielectric optical cavity) would be made of an optically nonlinear material and would be optimized for use in parametric frequency conversion by imposition of a spatially periodic permanent electric polarization. The poling (see figure) would suppress dispersions caused by both the material and the geometry of the optical cavity, thereby effecting quasi-matching of the phases of high-resonance-quality (high-Q) whispering-gallery electromagnetic modes. The quasi-phase-matching of the modes would serve to maximize the interactions among them. Such a resonator might be a prototype of a family of compact, efficient nonlinear devices for operation over a broad range of optical wavelengths. A little background information is prerequisite to a meaningful description of this proposal: (1) Described in several prior NASA Tech Briefs articles, the whispering-gallery modes in a component of spheroidal, disklike, or toroidal shape are waveguide modes that propagate circumferentially and are concentrated in a narrow toroidal region centered on the equatorial plane and located near the outermost edge. (2) For the sake of completeness, it must be stated that even though optical resonators of the type considered here are solid dielectric objects and light is confined within them by total internal reflection at dielectric interfaces without need for mirrors, such components are sometimes traditionally called cavities because their effects upon the light propagating within them are similar to those of true cavities bounded by mirrors. (3) For a given set of electromagnetic modes interacting with each other in an optically nonlinear material (e.g., modes associated with the frequencies involved in a frequency-conversion scheme), the threshold power for oscillation depends on the mode volumes and the mode-overlap integral. (4) Whispering-gallery modes are attractive in nonlinear optics because they maximize the effects of
Catheter steering using a Magnetic Resonance Imaging system.
Lalande, Viviane; Gosselin, Frederick P; Martel, Sylvain
2010-01-01
A catheter is successfully bent and steered by applying magnetic gradients inside a Magnetic Resonance Imaging system (MRI). One to three soft ferromagnetic spheres are attached at the distal tip of the catheter with different spacing between the spheres. Depending on the interactions between the spheres, progressive or discontinuous/jumping displacement was observed for increasing magnetic load. This phenomenon is accurately predicted by a simple theoretical dipole interaction model.
Dong, Zheng-Gao; Liu, Hui; Xu, Ming-Xiang; Li, Tao; Wang, Shu-Ming; Zhu, Shi-Ning; Zhang, X
2010-08-16
We demonstrate that the trapped magnetic resonance mode can be induced in an asymmetric double-bar structure for electromagnetic waves normally incident onto the double-bar plane, which mode otherwise cannot be excited if the double bars are equal in length. By adjusting the structural geometry, the trapped magnetic resonance becomes transparent with little resonance absorption when it happens in the dipolar resonance regime, a phenomenon so-called plasmonic analogue of electromagnetically induced transparency (EIT). This planar EIT-like metamaterial offers a great geometry simplification by combining the radiant and subradiant resonant modes in a single double-bar resonator.
Tepikian, S.
1988-01-01
Siberian Snakes provide a practical means of obtaining polarized proton beams in large accelerators. The effect of snakes can be understood by studying the dynamics of spin precession in an accelerator with snakes and a single spin resonance. This leads to a new class of energy independent spin depolarizing resonances, called snake resonances. In designing a large accelerator with snakes to preserve the spin polarization, there is an added constraint on the choice of the vertical betatron tune due to the snake resonances. 11 refs., 4 figs.
A simple electron cyclotron resonance ion source (abstract)a)
NASA Astrophysics Data System (ADS)
Welton, R. F.; Moran, T. F.; Feeney, R. K.; Thomas, E. W.
1996-03-01
A simple, all permanent magnet, 2.45 GHz electron cyclotron resonance ion source has been developed for the production of stable beams of low charge state ions from gaseous feed materials. The source can produce ˜1 mA of low energy (3 kV) singly charged ion current in the 10-4 Torr pressure range. The source can also be operated in a more efficient low-pressure mode at an order of magnitude lower pressure. In this latter range, for example, the ionization efficiency of Ar is estimated to be 1% with charge states up to Ar8+ present. Operation in the low-pressure mode requires low power input (˜20 W). These features make the source especially suited for use with small accelerator systems for a number of applications including ion implantation, mass spectrometry, and atomic collision experiments where multiply charged ions are desirable. Design details and performance characteristics of the source are presented.
Resonant X-ray emission with a standing wave excitation
Ruotsalainen, Kari O.; Honkanen, Ari-Pekka; Collins, Stephen P.; Monaco, Giulio; Moretti Sala, Marco; Krisch, Michael; Hämäläinen, Keijo; Hakala, Mikko; Huotari, Simo
2016-01-01
The Borrmann effect is the anomalous transmission of x-rays in perfect crystals under diffraction conditions. It arises from the interference of the incident and diffracted waves, which creates a standing wave with nodes at strongly absorbing atoms. Dipolar absorption of x-rays is thus diminished, which makes the crystal nearly transparent for certain x-ray wave vectors. Indeed, a relative enhancement of electric quadrupole absorption via the Borrmann effect has been demonstrated recently. Here we show that the Borrmann effect has a significantly larger impact on resonant x-ray emission than is observable in x-ray absorption. Emission from a dipole forbidden intermediate state may even dominate the corresponding x-ray spectra. Our work extends the domain of x-ray standing wave methods to resonant x-ray emission spectroscopy and provides means for novel spectroscopic experiments in d- and f-electron systems. PMID:26935531
Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity.
Zhang, Jing; Su, Yan; Shi, Qin; Qiu, An-Ping
2015-12-03
This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA). This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF) resonators, and the frequency output of two DETFs exhibits a differential shift. The dies of an SMRA are fabricated using silicon-on-insulator (SOI) processing and wafer-level vacuum packaging. This research aims to design a high-sensitivity SMRA because a high sensitivity allows for the acceleration signal to be easily demodulated by frequency counting techniques and decreases the noise level. This study applies the energy-consumed concept and the Nelder-Mead algorithm in the SMRA to address the design issues and further increase its sensitivity. Using this novel method, the sensitivity of the SMRA has been increased by 66.1%, which attributes to both the re-designed DETF and the reduced energy loss on the micro-lever. The results of both the closed-form and finite-element analyses are described and are in agreement with one another. A resonant frequency of approximately 22 kHz, a frequency sensitivity of over 250 Hz per g, a one-hour bias stability of 55 μg, a bias repeatability (1σ) of 48 μg and the bias-instability of 4.8 μg have been achieved.
Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity
Zhang, Jing; Su, Yan; Shi, Qin; Qiu, An-Ping
2015-01-01
This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA). This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF) resonators, and the frequency output of two DETFs exhibits a differential shift. The dies of an SMRA are fabricated using silicon-on-insulator (SOI) processing and wafer-level vacuum packaging. This research aims to design a high-sensitivity SMRA because a high sensitivity allows for the acceleration signal to be easily demodulated by frequency counting techniques and decreases the noise level. This study applies the energy-consumed concept and the Nelder-Mead algorithm in the SMRA to address the design issues and further increase its sensitivity. Using this novel method, the sensitivity of the SMRA has been increased by 66.1%, which attributes to both the re-designed DETF and the reduced energy loss on the micro-lever. The results of both the closed-form and finite-element analyses are described and are in agreement with one another. A resonant frequency of approximately 22 kHz, a frequency sensitivity of over 250 Hz per g, a one-hour bias stability of 55 μg, a bias repeatability (1σ) of 48 μg and the bias-instability of 4.8 μg have been achieved. PMID:26633425
Harmonically resonant cavity as a bunch-length monitor
NASA Astrophysics Data System (ADS)
Roberts, B.; Hannon, F.; Ali, M. M.; Forman, E.; Grames, J.; Kazimi, R.; Moore, W.; Pablo, M.; Poelker, M.; Sanchez, A.; Speirs, D.
2016-05-01
A compact, harmonically resonant cavity with fundamental resonant frequency 1497 MHz was used to evaluate the temporal characteristics of electron bunches produced by a 130 kV dc high voltage spin-polarized photoelectron source at the Continuous Electron Beam Accelerator Facility (CEBAF) photoinjector, delivered at 249.5 and 499 MHz repetition rates and ranging in width from 45 to 150 picoseconds (FWHM). A cavity antenna attached directly to a sampling oscilloscope detected the electron bunches as they passed through the cavity bore with a sensitivity of ˜1 mV /μ A . The oscilloscope waveforms are a superposition of the harmonic modes excited by the beam, with each cavity mode representing a term of the Fourier series of the electron bunch train. Relatively straightforward post-processing of the waveforms provided a near-real time representation of the electron bunches revealing bunch-length and the relative phasing of interleaved beams. The noninvasive measurements from the harmonically resonant cavity were compared to measurements obtained using an invasive RF-deflector-cavity technique and to predictions from particle tracking simulations.
Parametric resonance in the early Universe—a fitting analysis
NASA Astrophysics Data System (ADS)
Figueroa, Daniel G.; Torrentí, Francisco
2017-02-01
Particle production via parametric resonance in the early Universe, is a non-perturbative, non-linear and out-of-equilibrium phenomenon. Although it is a well studied topic, whenever a new scenario exhibits parametric resonance, a full re-analysis is normally required. To avoid this tedious task, many works present often only a simplified linear treatment of the problem. In order to surpass this circumstance in the future, we provide a fitting analysis of parametric resonance through all its relevant stages: initial linear growth, non-linear evolution, and relaxation towards equilibrium. Using lattice simulations in an expanding grid in 3+1 dimensions, we parametrize the dynamics' outcome scanning over the relevant ingredients: role of the oscillatory field, particle coupling strength, initial conditions, and background expansion rate. We emphasize the inaccuracy of the linear calculation of the decay time of the oscillatory field, and propose a more appropriate definition of this scale based on the subsequent non-linear dynamics. We provide simple fits to the relevant time scales and particle energy fractions at each stage. Our fits can be applied to post-inflationary preheating scenarios, where the oscillatory field is the inflaton, or to spectator-field scenarios, where the oscillatory field can be e.g. a curvaton, or the Standard Model Higgs.
Magnetic resonance force microscopy and a solid state quantum computer.
Pelekhov, D. V.; Martin, I.; Suter, A.; Reagor, D. W.; Hammel, P. C.
2001-01-01
A Quantum Computer (QC) is a device that utilizes the principles of Quantum Mechanics to perform computations. Such a machine would be capable of accomplishing tasks not achievable by means of any conventional digital computer, for instance factoring large numbers. Currently it appears that the QC architecture based on an array of spin quantum bits (qubits) embedded in a solid-state matrix is one of the most promising approaches to fabrication of a scalable QC. However, the fabrication and operation of a Solid State Quantum Computer (SSQC) presents very formidable challenges; primary amongst these are: (1) the characterization and control of the fabrication process of the device during its construction and (2) the readout of the computational result. Magnetic Resonance Force Microscopy (MRFM)--a novel scanning probe technique based on mechanical detection of magnetic resonance-provides an attractive means of addressing these requirements. The sensitivity of the MRFM significantly exceeds that of conventional magnetic resonance measurement methods, and it has the potential for single electron spin detection. Moreover, the MRFM is capable of true 3D subsurface imaging. These features will make MRFM an invaluable tool for the implementation of a spin-based QC. Here we present the general principles of MRFM operation, the current status of its development and indicate future directions for its improvement.
Rb optical resonance inside a random porous medium
NASA Astrophysics Data System (ADS)
Villalba, S.; Failache, H.; Laliotis, A.; Lenci, L.; Barreiro, S.; Lezama, A.
2013-01-01
We studied resonant laser interaction with Rb atoms confined to the interstitial cavities of a random porous glass. Due to diffusive light propagation, the effect of atomic absorption on the light scattered by the sample is almost entirely compensated by atomic fluorescence at low atomic densities. For higher densities, radiation trapping increases the probability of non-radiative decay via atom-wall collisions. A simple connection of the fluorescence/absorption yield to the sample porosity is given.
Rb optical resonance inside a random porous medium.
Villalba, S; Failache, H; Laliotis, A; Lenci, L; Barreiro, S; Lezama, A
2013-01-15
We studied resonant laser interaction with Rb atoms confined to the interstitial cavities of a random porous glass. Due to diffusive light propagation, the effect of atomic absorption on the light scattered by the sample is almost entirely compensated by atomic fluorescence at low atomic densities. For higher densities, radiation trapping increases the probability of nonradiative decay via atom-wall collisions. A simple connection of the fluorescence/absorption yield to the sample porosity is given.
The multipole resonance probe: characterization of a prototype
NASA Astrophysics Data System (ADS)
Lapke, Martin; Oberrath, Jens; Schulz, Christian; Storch, Robert; Styrnoll, Tim; Zietz, Christian; Awakowicz, Peter; Brinkmann, Ralf Peter; Musch, Thomas; Mussenbrock, Thomas; Rolfes, Ilona
2011-08-01
The multipole resonance probe (MRP) was recently proposed as an economical and industry compatible plasma diagnostic device (Lapke et al 2008 Appl. Phys. Lett. 93 051502). This communication reports the experimental characterization of a first MRP prototype in an inductively coupled argon/nitrogen plasma at 10 Pa. The behavior of the device follows the predictions of both an analytical model and a numerical simulation. The obtained electron densities are in excellent agreement with the results of Langmuir probe measurements.
Hyperpolarized Magnetic Resonance as a Sensitive Detector of Metabolic Function
2015-01-01
Hyperpolarized magnetic resonance allows for noninvasive measurements of biochemical reactions in vivo. Although this technique provides a unique tool for assaying enzymatic activities in intact organs, the scope of its application is still elusive for the wider scientific community. The purpose of this review is to provide key principles and parameters to guide the researcher interested in adopting this technology to address a biochemical, biomedical, or medical issue. It is presented in the form of a compendium containing the underlying essential physical concepts as well as suggestions to help assess the potential of the technique within the framework of specific research environments. Explicit examples are used to illustrate the power as well as the limitations of hyperpolarized magnetic resonance. PMID:25369537
Nondegenerate Parametric Resonance in a Tunable Superconducting Cavity
NASA Astrophysics Data System (ADS)
Wustmann, Waltraut; Shumeiko, Vitaly
2017-08-01
We develop a theory for nondegenerate parametric resonance in a tunable superconducting cavity. We focus on nonlinear effects that are caused by nonlinear Josephson elements connected to the cavity. We analyze parametric amplification in a strong nonlinear regime at the parametric-instability threshold, and we calculate maximum gain values. Above the threshold, in the parametric-oscillator regime, the cavity linear response diverges at the oscillator frequency at all pump strengths. We show that this divergence is related to the continuous degeneracy of the free oscillator state with respect to the phase. Applying on-resonance input lifts the degeneracy and removes the divergence. We also investigate quantum noise squeezing. It is shown that in the strong amplification regime, the noise undergoes four-mode squeezing, and that, in this regime, the output signal-to-noise ratio can significantly exceed the input value. We also analyze the intermode frequency conversion and identify the parameters at which full conversion is achieved.
A resonant ionization laser ion source at ORNL
NASA Astrophysics Data System (ADS)
Liu, Y.; Stracener, D. W.
2016-06-01
Multi-step resonance laser ionization has become an essential tool for the production of isobarically pure radioactive ion beams at the isotope separator on-line (ISOL) facilities around the world. A resonant ionization laser ion source (RILIS) has been developed for the former Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory. The RILIS employs a hot-cavity ion source and a laser system featuring three grating-tuned and individually pumped Ti:Sapphire lasers, especially designed for stable and simple operation. The RILIS has been installed at the second ISOL production platform of former HRIBF and has successfully provided beams of exotic neutron-rich Ga isotopes for beta decay studies. This paper reports the features, advantages, limitations, and on-line and off-line performance of the RILIS.
Precession of a rapidly rotating cylinder flow: traverse through resonance
NASA Astrophysics Data System (ADS)
Lopez, Juan; Marques, Francisco
2014-11-01
The flow in a rapidly rotating cylinder that is titled and also rotating around another axis can undergo sudden transitions to turbulence. Experimental observations of this have been associated with triadic resonances. The experimental and theoretical results are well-established in the literature, but there remains a lack of understanding of the physical mechanisms at play in the sudden transition from laminar to turbulent flow with very small variations in the governing parameters. Here, we present direct numerical simulations of a traverse in parameter space through an isolated resonance, and describe in detail the bifurcations involved in the sudden transition. U.S. National Science Foundation Grant CBET-1336410 and Spanish Ministry of Education and Science Grant (with FEDER funds) FIS2013-40880.
The development of the birdcage resonator: a historical perspective.
Hayes, Cecil E
2009-11-01
The author gives a personal account of the development of the birdcage resonator while he worked at GE Medical Systems. The emphasis is on promoting an intuitive understanding of the underlying principles of RF coil design by recounting the assumptions, misconceptions, and reasoning involved in addressing the challenging problems in a new field of technology. Topics covered include the historic context of early MRI development, the critical role of RF coil technology in high field imaging, the need for an RF shield, the importance of distributed capacitance, the scientific controversies over magnetic field strength for imaging, a comparison of the birdcage design to an earlier Technicare phased coil, the distribution of electric fields in birdcage resonators, and the limitations of birdcages at very high fields. The author often cites less well-known patent literature on RF coil technology.
Active flat optics using a guided mode resonance.
Kim, Soo Jin; Brongersma, Mark L
2017-01-01
Dynamically-controlled flat optics relies on achieving active and effective control over light-matter interaction in ultrathin layers. A variety of metasurface designs have achieved efficient amplitude and phase modulation. Particularly, noteworthy progress has been made with the incorporation of newly emerging electro-optical materials into such metasurfaces, including graphene, phase change materials, and transparent conductive oxides. In this Letter, we demonstrate dynamic light-matter interaction in a silicon-based subwavelength grating that supports a guided mode resonance. By overcoating the grating with indium tin oxide as an electrically tunable material, its reflectance can be tuned from 4% to 86%. Guided mode resonances naturally afford higher optical quality factors than the optical antennas used in the construction of metasurfaces. As such, they facilitate more effective control over the flow of light within the same layer thickness.
Superharmonic resonances in a strongly coupled cavity-atom system
NASA Astrophysics Data System (ADS)
Buks, Eyal; Deng, Chunqing; Orgazzi, Jean-Luc F. X.; Otto, Martin; Lupascu, Adrian
2016-09-01
We study a system consisting of a superconducting flux qubit strongly coupled to a microwave cavity. The fundamental cavity mode is externally driven and the response is investigated in the weak nonlinear regime. We find that near the crossing point, at which the resonance frequencies of the cavity mode and qubit coincide, the sign of the Kerr coefficient changes, and consequently the type of nonlinear response changes from softening to hardening. Furthermore, the cavity response exhibits superharmonic resonances (SHR) when the ratio between the qubit frequency and the cavity fundamental mode frequency is tuned close to an integer value. The nonlinear response is characterized by the method of intermodulation and both signal and idler gains are measured. The experimental results are compared with theoretical predictions and good qualitative agreement is obtained. The SHRs have potential for applications in quantum amplification and generation of entangled states of light.
First resonant tunneling via a light-hole ground state
NASA Astrophysics Data System (ADS)
Lampin, J. F.; Mollot, F.
1998-07-01
We report the demonstration of resonant tunneling of light-holes through an AlAs/GaAs 0.7P 0.3 double-barrier heterostructure. The tensile strain in the quantum well reverses the order of the light- and heavy-hole levels, the first light-hole level becoming the ground state. The I( V) characteristics are measured at different temperatures and compared to those of a standard AlAs/GaAs unstrained structure. The peak current density of the first light-hole resonance and its peak-to-valley current ratio are enhanced. They reach 28 A/cm 2 and 3.4 : 1 at 15 K. A negative differential resistance is observed up to 250 K.
Kondo resonance in tunneling phenomena through a single quantum level
Oguri, A.; Ishii, H. ); Saso, T. )
1995-02-15
Effects of Coulomb repulsion on the process of resonant tunneling through a single quantum level are studied by applying the quantum Monte Carlo method and the maximum-entropy method to the Wolf model on a one-dimensional chain. In the calculated spectral function there is a sharp Kondo peak near the chemical potential [mu], which contributes to the resonance tunneling. Correspondingly, the conductance calculated by using the Friedel sum rule shows the expected transparency, i.e., the transmission probability is almost unity when [mu] is in the range [epsilon][sub 0][lt][mu][lt][epsilon][sub 0]+[ital U], where [epsilon][sub 0] is the on-site energy of the single quantum level and [ital U] is the Coulomb repulsion.
Operational characteristics of a 200 C LC parallel resonant circuit
NASA Technical Reports Server (NTRS)
Baumann, Eric D.; Hammoud, Ahmad N.
1995-01-01
Research efforts are currently underway at the NASA Lewis Research Center to design and demonstrate an inverter capable of operating with a baseplate temperature of 200 C. In support of this project, various electrical components including capacitors, inductors, transformers, cables, and semiconductor switches are being developed or evaluated for integration into the inverter. In this work, a parallel LC resonant circuit was constructed and evaluated under simultaneous electrical and thermal stressing. The tests were performed in the temperature range of 25 to 200 C with an applied voltage of up to 90 V, 20 kHz. The individual components were comprised of high temperature film capacitors and powder core inductors developed in-house. The circuit was characterized in terms of the component currents and case temperatures as well as frequency of resonance as a function of applied bias and temperature. The results obtained, which have indicated good functional stability up to 200 C, are presented and discussed.
NASA Astrophysics Data System (ADS)
Albert, Christopher G.; Heyn, Martin F.; Kapper, Gernot; Kasilov, Sergei V.; Kernbichler, Winfried; Martitsch, Andreas F.
2016-08-01
Toroidal torque generated by neoclassical viscosity caused by external non-resonant, non-axisymmetric perturbations has a significant influence on toroidal plasma rotation in tokamaks. In this article, a derivation for the expressions of toroidal torque and radial transport in resonant regimes is provided within quasilinear theory in canonical action-angle variables. The proposed approach treats all low-collisional quasilinear resonant neoclassical toroidal viscosity regimes including superbanana-plateau and drift-orbit resonances in a unified way and allows for magnetic drift in all regimes. It is valid for perturbations on toroidally symmetric flux surfaces of the unperturbed equilibrium without specific assumptions on geometry or aspect ratio. The resulting expressions are shown to match the existing analytical results in the large aspect ratio limit. Numerical results from the newly developed code NEO-RT are compared to calculations by the quasilinear version of the code NEO-2 at low collisionalities. The importance of the magnetic shear term in the magnetic drift frequency and a significant effect of the magnetic drift on drift-orbit resonances are demonstrated.
Albert, Christopher G.; Heyn, Martin F.; Kapper, Gernot; Kernbichler, Winfried; Martitsch, Andreas F.; Kasilov, Sergei V.
2016-08-15
Toroidal torque generated by neoclassical viscosity caused by external non-resonant, non-axisymmetric perturbations has a significant influence on toroidal plasma rotation in tokamaks. In this article, a derivation for the expressions of toroidal torque and radial transport in resonant regimes is provided within quasilinear theory in canonical action-angle variables. The proposed approach treats all low-collisional quasilinear resonant neoclassical toroidal viscosity regimes including superbanana-plateau and drift-orbit resonances in a unified way and allows for magnetic drift in all regimes. It is valid for perturbations on toroidally symmetric flux surfaces of the unperturbed equilibrium without specific assumptions on geometry or aspect ratio. The resulting expressions are shown to match the existing analytical results in the large aspect ratio limit. Numerical results from the newly developed code NEO-RT are compared to calculations by the quasilinear version of the code NEO-2 at low collisionalities. The importance of the magnetic shear term in the magnetic drift frequency and a significant effect of the magnetic drift on drift-orbit resonances are demonstrated.
Low-frequency nuclear quadrupole resonance with a dc SQUID
Chang, J.W.
1991-07-01
Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs.
Low-frequency nuclear quadrupole resonance with a dc SQUID
Chang, J.W.
1991-07-01
Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs.
Quantum resonance catastrophe for conductance through a periodically driven barrier
NASA Astrophysics Data System (ADS)
Thuberg, Daniel; Reyes, Sebastián A.; Eggert, Sebastian
2016-05-01
We consider the quantum conductance in a tight-binding chain with a locally applied potential which is oscillating in time. The steady state for such a driven impurity can be calculated exactly for any energy and applied potential using the Floquet formalism. The resulting transmission has a nontrivial, nonmonotonic behavior depending on incoming momentum, driving frequency, and the strength of the applied periodic potential. Hence there is an abundance of tuning possibilities, which allows finding the resonances of total reflection for any choice of incoming momentum and periodic potential. Remarkably, this implies that even for an arbitrarily small infinitesimal impurity potential it is always possible to find a resonance frequency at which there is a catastrophic breakdown of the transmission T =0 . The points of zero transmission are closely related to the phenomenon of Fano resonances at dynamically created bound states in the continuum. The results are relevant for a variety of one-dimensional systems where local AC driving is possible, such as quantum nanodot arrays, ultracold gases in optical lattices, photonic crystals, or molecular electronics.
Stochastic resonance-a nonlinear control theory interpretation
NASA Astrophysics Data System (ADS)
Repperger, D. W.; Farris, K. A.
2010-07-01
Stochastic resonance (SR) is an effect that has been known (Benzi, R., Sutera, A., and Vulpiani, A. (1981), 'The Mechanism of Stochastic Resonance', Journal of Physics, A14, L453-L457) for almost three decades and has been extensively studied in biology, statistics, signal processing and in numerous other eclectic areas (Wiesenfeld, K., and Moss, F. (1995), 'Stochastic Resonance and the Benefits of Noise: From Ice Ages to Crayfish and Squids', Nature, 373, 33-36). Herein, a nonlinear control theory analysis is conducted on how to better understand the class of systems that may exhibit the SR effect. Using nonlinear control theory methods, equilibrium points are manipulated to create the SR response (similar to shaping dynamical response in a phase plane). From this approach, a means of synthesising and designing the appropriate class of nonlinear systems is introduced. New types of nonlinear dynamics that demonstrate the SR effects are discovered, which may have utility in control theory as well as in many diverse applications. A numerical simulation illustrates some powerful attributes of these systems.
NASA Astrophysics Data System (ADS)
Ahmadivand, Arash; Sinha, Raju; Pala, Nezih
2015-08-01
We introduce a platform based on plasmonic metamaterials to design various optical devices. A simple structure brokenring with a nanodisk at the center is utilized to excite and hybridize the plasmon resonant modes. We show that the proposed nanoantenna is able to support strong sub- and superradiant plasmon resonances because of its unique geometrical features. Using the concentric ring/disk in a dimer orientation as a nanoantenna on a multilayer metasurface consisting of graphene monolayer, we induced double sharp plasmonic Fano resonant modes in the transmission window across the visible to the near-infrared region. Considering the strong polarization-dependency of the broken-ring/disk dimer antenna, it is shown that the proposed plasmonic metamaterial can be tailored as an optical router device for fast switching applications. This understanding opens new paths to employ plasmonic metamaterials with simple geometrical nanoscale blocks for sensing and switching applications.
Tsekos, Nikolaos V; Ozcan, Alpay; Christoforou, Eftychios
2005-11-01
The aim of this work is to develop a remotely controlled manipulator to perform minimally invasive diagnostic and therapeutic interventions in the abdominal and thoracic cavities, with real-time magnetic resonance imaging (MRI) guidance inside clinical cylindrical MR scanners. The manipulator is composed of a three degree of freedom Cartesian motion system, which resides outside the gantry of the scanner, and serves as the holder and global positioner of a three degree of freedom arm which extends inside the gantry of the scanner At its distal end, the arm's end-effector can carry an interventional tool such as a biopsy needle, which can be advanced to a desired depth by means of a seventh degree of freedom. These seven degrees of freedom, provided by the entire assembly, offer extended manipulability to the device and a wide envelope of operation to the user, who can select a trajectory suitable for the procedure. The device is constructed of nonmagnetic and nonconductive fiberglass, and carbon fiber composite materials, to minimize artifacts and distortion on the MR images as well as eliminate effects on its operation from the high magnetic field and the fast switching magnetic field gradients used in MR imaging. A user interface was developed for man-in-the-loop control of the device using real-time MR images. The user interface fuses all sensor signals (MR and manipulator information) in a visualization, planning, and control command environment. Path planning is performed with graphical tools for setting the trajectory of insertion of the interventional tool using multislice and/or three dimensional MR images which are refreshed in real time. The device control is performed with an embedded computer which runs real-time control software. The manipulator compatibility with the MR environment and image-guided operation was tested on a 1.5 T MR scanner.
Ferromagnetic resonance in a topographically modulated permalloy film
NASA Astrophysics Data System (ADS)
Sklenar, J.; Tucciarone, P.; Lee, R. J.; Tice, D.; Chang, R. P. H.; Lee, S. J.; Nevirkovets, I. P.; Heinonen, O.; Ketterson, J. B.
2015-04-01
A major focus within the field of magnonics involves the manipulation and control of spin-wave modes. This is usually done by patterning continuous soft magnetic films. Here, we report on work in which we use topographic modifications of a continuous magnetic thin film, rather than lithographic patterning techniques, to modify the ferromagnetic resonance spectrum. To demonstrate this technique we have performed in-plane, broadband, ferromagnetic resonance studies on a 100-nm-thick permalloy film sputtered onto a colloidal crystal with individual sphere diameters of 200 nm. Effects resulting from the, ideally, sixfold-symmetric underlying colloidal crystal were studied as a function of the in-plane field angle through experiment and micromagnetic modeling. Experimentally, we find two primary modes; the ratio of the intensities of these two modes exhibits a sixfold dependence. Detailed micromagnetic modeling shows that both modes are quasiuniform and nodeless in the unit cell but that they reside in different demagnetized regions of the unit cell. Our results demonstrate that topographic modification of magnetic thin films opens additional directions for manipulating ferromagnetic resonant excitations.
Chaos and Beyond in a Water Filled Ultrasonic Resonance System
NASA Technical Reports Server (NTRS)
Lazlo, Adler; Yost, W.; Cantrell, John H.
2013-01-01
Finite amplitude ultrasonic wave resonances in a one-dimensional liquid-filled cavity, formed by a narrow band transducer and a plane reflector, are reported. The resonances are observed to include not only the expected harmonic and subharmonic signals (1,2) but chaotic signals as well. The generation mechanism requires attaining a threshold value of the driving amplitude that the liquid-filled cavity system becomes sufficiently nonlinear in response. The nonlinear features of the system were recently investigated via the construction of an ultrasonic interferometer having optical precision. The transducers were compressional, undamped quartz and lithium niobate crystals having the frequency range 1-10 MHz, driven by a high power amplifier. Both an optical diffraction system to characterize the diffraction pattern of laser light normally incident to the cavity and a receiving transducer attached to an aligned reflector with lapped flat and parallel surfaces were used to assess the generated resonance response in the cavity. At least 5 regions of excitation are identified.
Resonance compression of an acoustic beam in a crystal
Alshits, V. I. Bessonov, D. A.; Lyubimov, V. N.
2016-04-15
The resonance excitation of an intense acoustic beam in a crystal is described for a special geometry of pump-wave reflection from the crystal surface. The resonance appears in the vicinity of the total internal reflection angle under the condition that the wave field in a compressed reflected beam propagating almost parallel to the surface is close to the volume eigenmode satisfying the free boundary condition. Criteria for the existence of such modes are considered in detail. Conversion conditions are analyzed under which a “parasitic” reflected wave of the same branch as the incident wave is absent and entire energy from the incident wave falls within a narrow intense acoustic beam of another branch. It is shown that, when the surface is chosen parallel to the crystal symmetry plane, the conversion criterion is reduced to the sole condition on the elastic moduli of the medium. Analysis is performed by analytic and numerical methods for skew cuts of monoclinic, rhombic, trigonal, and hexagonal crystals, when the boundary is the symmetry plane, while the sagittal plane has no symmetry. A number of crystals are found in which resonance excitation is very close to conversion.
Resonance scattering by fish schools: A comparison of two models.
Raveau, M; Feuillade, C
2016-01-01
The effective medium method is used to investigate resonance scattering from schools of fish with gas-filled swim bladders, as a function of frequency and azimuth. Calculations are also performed with a coupled differential equation model, which incorporates both multiple scattering between fish and wave interference interactions of their scattered fields [Feuillade, Nero, and Love, J. Acoust. Soc. Am. 99, 196-208 (1996)]. A theoretical comparison of the models for idealized spherical schools shows good agreement over the entire resonance region in the forward direction, where interference interactions have a minimal effect. Good agreement is also seen in back scattering at low frequencies, where the wavelength λ≥4s, and s is the average nearest neighbor fish separation. If λ<4s, the models diverge in back scattering, and the effective medium method fails. This can be critically important when migrations of schools to deeper water cause the collective resonance frequency to increase. Multiple scattering interactions are negligible when |4πnf(b)(2)/k|⪅0.01, where n is the fish number density, f(b) is the individual fish scattering amplitude, and k=2π/λ. A comparison with forward scattering data shows very good agreement for both models, and indicates a method for estimating fish abundance. For back scattering data, the effective medium method diverges strongly when λ<4s.
Resonance compression of an acoustic beam in a crystal
NASA Astrophysics Data System (ADS)
Alshits, V. I.; Bessonov, D. A.; Lyubimov, V. N.
2016-04-01
The resonance excitation of an intense acoustic beam in a crystal is described for a special geometry of pump-wave reflection from the crystal surface. The resonance appears in the vicinity of the total internal reflection angle under the condition that the wave field in a compressed reflected beam propagating almost parallel to the surface is close to the volume eigenmode satisfying the free boundary condition. Criteria for the existence of such modes are considered in detail. Conversion conditions are analyzed under which a "parasitic" reflected wave of the same branch as the incident wave is absent and entire energy from the incident wave falls within a narrow intense acoustic beam of another branch. It is shown that, when the surface is chosen parallel to the crystal symmetry plane, the conversion criterion is reduced to the sole condition on the elastic moduli of the medium. Analysis is performed by analytic and numerical methods for skew cuts of monoclinic, rhombic, trigonal, and hexagonal crystals, when the boundary is the symmetry plane, while the sagittal plane has no symmetry. A number of crystals are found in which resonance excitation is very close to conversion.
A resonant biaxial Helmholtz coil employing a fractal capacitor bank
NASA Astrophysics Data System (ADS)
Martin, James E.
2013-09-01
The design and construction of a series resonant biaxial Helmholtz coil for the production of magnetic fields as large as 500 G in the range of 100-2500 Hz is described. Important aspects of ac coil design are discussed, including: minimizing power losses due to the expected Joule heating, self-induced eddy currents, and skin resistance; controlling the stray capacitance; maximizing field homogeneity; and keeping peak voltages at acceptable levels. The design and construction of a computer-controlled, optically isolated fractal capacitor bank is then treated, and various aspects of capacitor selection and characterization were discussed. The system performance is demonstrated, including stability and the possibility of field component dephasing with typical magnetic samples.
A resonant biaxial Helmholtz coil employing a fractal capacitor bank.
Martin, James E
2013-09-01
The design and construction of a series resonant biaxial Helmholtz coil for the production of magnetic fields as large as 500 G in the range of 100-2500 Hz is described. Important aspects of ac coil design are discussed, including: minimizing power losses due to the expected Joule heating, self-induced eddy currents, and skin resistance; controlling the stray capacitance; maximizing field homogeneity; and keeping peak voltages at acceptable levels. The design and construction of a computer-controlled, optically isolated fractal capacitor bank is then treated, and various aspects of capacitor selection and characterization were discussed. The system performance is demonstrated, including stability and the possibility of field component dephasing with typical magnetic samples.
Magnetic material arrangement in oriented termites: a magnetic resonance study
NASA Astrophysics Data System (ADS)
Alves, O. C.; Wajnberg, E.; de Oliveira, J. F.; Esquivel, D. M. S.
2004-06-01
Temperature dependence of the magnetic resonance is used to study the magnetic material in oriented Neocapritermes opacus (N.o.) termite, the only prey of the migratory ant Pachycondyla marginata (P.m.). A broad line in the g=2 region, associated to isolated nanoparticles shows that at least 97% of the magnetic material is in the termite's body (abdomen + thorax). From the temperature dependence of the resonant field and from the spectral linewidths, we estimate the existence of magnetic nanoparticles 18.5 ± 0.3 nm in diameter and an effective magnetic anisotropy constant, Keff between 2.1 and 3.2 × 10 4 erg/cm 3. A sudden change in the double integrated spectra at about 100 K for N.o. with the long body axis oriented perpendicular to the magnetic field can be attributed to the Verwey transition, and suggests an organized film-like particle system.
Acoustic Agglomeration Process of Fine Particles in a Resonance Structure
NASA Astrophysics Data System (ADS)
Shi, Chen-hao; Zhang, Jian; Zhao, Yun; Liang, Jie
2017-07-01
It was proved that the acoustic agglomeration technology has a good application prospect in the removal of fine particles. In this paper, a removal system of acoustic agglomeration is constructed by the acoustic resonance structure. With the finite element simulation model, the effect and condition of sound pressure level (SPL) increment of high intensity sound in the resonance structure are defined. In the experiment, the contrast of the sampling weight and particle size distribution changes of fine particles was compared under different operating conditions to examine the effect of acoustic agglomeration on the removal efficiency of fine particles. The results show the SPL increment of 10dB is obtained with SPL 145-165 dB when the working frequency is changed from 400 to 2000 Hz. Under the action of acoustic agglomeration, fine particles in the aerosol were significantly reduced, and the removal effect is markedly improved with the increase of SPL.
NASA Astrophysics Data System (ADS)
Fuke, K.; Tona, M.; Fujihara, A.; Sakurai, M.; Ishikawa, H.
2012-08-01
Nuclear magnetic resonance (NMR) technique is a well-established powerful tool to study the physical and chemical properties of a wide range of materials. However, presently, NMR applications are essentially limited to materials in the condensed phase. Although magnetic resonance was originally demonstrated in gas phase molecular beam experiments, no application to gas phase molecular ions has yet been demonstrated. Here, we present a novel principle of NMR detection for gas phase ions based on a "magnetic resonance acceleration" technique and describe the design and construction of an apparatus which we are developing. We also present an experimental technique and some results on the formation and manipulation of cold ion packets in a strong magnetic field, which are the key innovations to detect NMR signal using the present method. We expect this novel method to lead new realm for the study of mass-selected gas-phase ions with interesting applications in both fundamental and applied sciences.
Intrinsic noise induced coherence resonance in a glow discharge plasma
NASA Astrophysics Data System (ADS)
Shaw, Pankaj Kumar; Saha, Debajyoti; Ghosh, Sabuj; Janaki, M. S.; Iyengar, A. N. Sekar
2015-04-01
Experimental evidence of intrinsic noise induced coherence resonance in a glow discharge plasma is being reported. Initially the system is started at a discharge voltage (DV) where it exhibited fixed point dynamics, and then with the subsequent increase in the DV spikes were excited which were few in number and with further increase of DV the number of spikes as well as their regularity increased. The regularity in the interspike interval of the spikes is estimated using normalized variance. Coherence resonance was determined using normalized variance curve and also corroborated by Hurst exponent and power spectrum plots. We show that the regularity of the excitable spikes in the floating potential fluctuation increases with the increase in the DV, up to a particular value of DV. Using a Wiener filter, we separated the noise component which was observed to increase with DV and hence conjectured that noise can play an important role in the generation of the coherence resonance. From an anharmonic oscillator equation describing ion acoustic oscillations, we have been able to obtain a FitzHugh-Nagumo like model which has been used to understand the excitable dynamics of glow discharge plasma in the presence of noise. The numerical results agree quite well with the experimental results.
NASA Astrophysics Data System (ADS)
Lu, Kuan; Wu, Jiu Hui; Jing, Li; Guan, Dong
2017-03-01
In this paper, an elastic metamaterial beam with a novel two-degree-of-freedom local resonator is investigated theoretically, and the dispersion relation is calculated by using transfer matrix (TM). In order to confirm the existence of band gaps, the transmission spectrum of flexural wave are also studied by using finite element method. The formation mechanism of the flexural vibration bandgaps (FVBGs) are further analyzed by studying the displacement fields of the eigenmodes at the band-gap edges. At last, the evolution of the dispersion relations with the increasing of the distance from the one side rubber to the center of the local resonance mass are discussed in detail, and the effects of the outside diameter of the Cu ring and the equivalent stiffness k of the rubbers on the FVBGs are also investigated. Through the above analysis, we can draw the following conclusions, due to the unequal of the torques provided by the two rubbers, two different rotational vibrations of local resonance mass with two different local resonance frequencies are introduced in the local resonance system, thus the elastic metamaterial beam shows two FVBGs at low frequencies. The theoretical results are in good agreement with the numerical results. The magnitude of torques introduced in the local resonance system can obviously affect the locations of the FVBGs. With the asymmetry decreasing, the frequency region of the first FVBG moves to the higher value, while that of the second FVBG tends to the lower value, and when the two torques are equal, the two FVBGs coupled into one wider gap. For the elastic metamaterial beam with heavy resonance mass and weak rubbers is appropriate to obtain a lower band gap, and the total width of the FVBGs becomes wider. However, it does just the opposite under the condition of the case with light Cu ring and strong rubbers, but the total width of the band gaps also becomes wider. The propagation properties of the flexural wave in the designed local
Transforming Fabry-Pérot resonances into a Tamm mode
NASA Astrophysics Data System (ADS)
Durach, Maxim; Rusina, Anastasia
2012-12-01
We propose an optical structure composed of two metal nanolayers enclosing a distributed Bragg reflector (DBR) mirror. The structure is an open photonic system whose bound modes are coupled to external radiation. We apply the special theoretical treatment based on inversion symmetry of the structure to classify its resonances. We show that the structure supports resonances transitional between Fabry-Pérot modes and Tamm plasmons. When the dielectric contrast of the DBR is removed these modes are a pair of conventional Fabry-Pérot resonances. They spectrally merge into a Tamm mode at high contrast. The optical properties of the structure in the frequency range of the DBR stop band, including highly beneficial 50% transmittivity through thick structures with sub-skin-depth metal films, are determined by the hybrid quasinormal modes of the open nonconservative structure under consideration. The results can find a broad range of applications in photonics and optoelectronics, including the possibility of coherent control over optical fields in the class of structures similar to the one proposed here.
High energy resolution off-resonant spectroscopy: A review
NASA Astrophysics Data System (ADS)
Błachucki, Wojciech; Hoszowska, Joanna; Dousse, Jean-Claude; Kayser, Yves; Stachura, Regina; Tyrała, Krzysztof; Wojtaszek, Klaudia; Sá, Jacinto; Szlachetko, Jakub
2017-10-01
We review the high energy resolution off-resonant spectroscopy (HEROS) technique. HEROS probes the unoccupied electronic states of matter in a single-shot manner thanks to the combination of off-resonant excitation around atomic core states using wavelength dispersive X-ray detection setups. In this review we provide a general introduction to the field of X-ray spectroscopy together with the specification of the available X-ray techniques and X-ray methodologies. Next, the theoretical description of the HEROS approach is introduced with a special focus on the derivation of the X-ray emission and X-ray absorption correspondence relation at off-resonant excitation conditions. Finally, a number of experimental HEROS reports are reviewed in the field of chemistry and material science. We emphasize the applicability of HEROS to pulsed X-ray sources, like X-ray free electron lasers, and support the review with experimental examples. The review is complemented with perspectives on and possible further applications of the HEROS technique to the field of X-ray science.
A Microring Resonator Sensor for Sensitive Detection of 1,3,5-Trinitrotoluene (TNT)
Orghici, Rozalia; Lützow, Peter; Burgmeier, Jörg; Koch, Jan; Heidrich, Helmut; Schade, Wolfgang; Welschoff, Nina; Waldvogel, Siegfried
2010-01-01
A microring resonator sensor device for sensitive detection of the explosive 1,3,5-trinitrotoluene (TNT) is presented. It is based on the combination of a silicon microring resonator and tailored receptor molecules. PMID:22163576
NASA Astrophysics Data System (ADS)
Tkach, Igor; Sicoli, Giuseppe; Höbartner, Claudia; Bennati, Marina
2011-04-01
We present a dual-mode resonator operating at/near 94 GHz (W-band) microwave frequencies and supporting two microwave modes with the same field polarization at the sample position. Numerical analysis shows that the frequencies of both modes as well as their frequency separation can be tuned in a broad range up to GHz. The resonator was constructed to perform pulsed ELDOR experiments with a variable separation of "pump" and "detection" frequencies up to Δ ν = 350 MHz. To examine its performance, test ESE/PELDOR experiments were performed on a representative biradical system.
Fan, N.Q.; Clarke, J. )
1991-06-01
A sensitive spectrometer, based on a dc superconducting quantum interference device, for the direct detection of low-frequency pulsed nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR), is described. The frequency response extends from about 10 to 200 kHz, and the recovery time after the magnetic pulse is removed is typically 50 {mu}s. As examples, NMR spectra are shown from Pt and Cu metal powders in a magnetic field of 6 mT, and NQR spectra are shown from {sup 2}D in a tunneling methyl group and {sup 14}N in NH{sub 4}ClO{sub 4}.
A Piezoelectric Micropump Using Resonance Drive with High Power Density
NASA Astrophysics Data System (ADS)
Park, Jung-Ho; Yokota, Shinichi; Yoshida, Kazuhiro
As fluid power sources mounted on practical and powerful micromachines such as in-pipe working micromachines using fluid power, micropumps having high power density are required. A piezoelectric micropump using resonance drive is proposed and developed. First, a large model of the proposed micropump is fabricated and the effectiveness of resonance drive is confirmed through basic experiments. Second, a micropump having the size of 9mm diameter and 10mm length for practical applications is fabricated. Next, frequency characteristics and load characteristics of the pressure-dependent flow rate are experimentally investigated with various structural parameters for the optimal design. Through those experiments, the optimal amounts of additional mass and valve thickness are experimentally obtained for stable and high performance of the micropump. The maximum flow rate of 80mm3/s, maximum pumping pressure of 0.32MPa and maximum power of 8.7mW are obtained at the driving frequency of 2.0kHz. Finally, the feasibility of developing the piezoelectric micropump using resonance drive is confirmed through comparisons of maximum power density among conventional micropumps.
Liao, Jie; Wu, Xiang; Liu, Liying; Xu, Lei
2016-04-18
The spectral mode density in optical micro-bubble resonators is reduced by introducing a loss element of UV curable adhesive to selectively suppress the whispering gallery modal resonances. Asymmetric Fano resonant profile appears after spectral simplification, and the sharp slope amplifies the detecting intensity change by 4.3 times when sensing the liquid core refractive index change.
Probing a new strongly interacting sector via composite diboson resonances
NASA Astrophysics Data System (ADS)
Ko, P.; Yu, Chaehyun; Yuan, Tzu-Chiang
2017-06-01
Diphoton resonance was a crucial discovery mode for the 125 GeV Standard Model Higgs boson at the Large Hadron Collider (LHC). This mode or the more general diboson modes may also play an important role in probing for new physics beyond the Standard Model. In this paper, we consider the possibility that a diphoton resonance is due to a composite scalar or pseudoscalar boson, whose constituents are either new hyperquarks Q or scalar hyperquarks Q ˜ confined by a new hypercolor force at a confinement scale Λh. Assuming the mass mQ (or mQ ˜) ≫Λh, a diphoton resonance could be interpreted as either a Q Q ¯ (1S0) state ηQ with JP C=0-+ or a Q ˜ Q˜ †(1S0) state ηQ ˜ with JP C=0++. For the Q Q ¯ scenario, there will be a spin-triplet partner ψQ which is slightly heavier than ηQ due to the hyperfine interactions mediated by hypercolor gluon exchange; while for the Q ˜Q˜† scenario, the spin-triplet partner χQ ˜ arises from higher radial excitation with nonzero orbital angular momentum. We consider productions and decays of ηQ, ηQ ˜, ψQ, and χQ ˜ at the LHC using the nonrelativistic QCD factorization approach. We discuss how to test these scenarios by using the Drell-Yan process and the forward dijet azimuthal angular distributions to determine the JP C quantum number of the diphoton resonance. Constraints on the parameter space can be obtained by interpreting some of the small diphoton "excesses" reported by the LHC as the composite scalar or pseudoscalar of the model. Another important test of the model is the presence of a nearby hypercolor-singlet but color-octet state like the 1S0 state ηQ8 or ηQ˜8, which can also be constrained by dijet or monojet plus monophoton data. Both possibilities of a large or small width of the resonance can be accommodated, depending on whether the hyper-glueball states are kinematically allowed in the final state or not.
Resonance of a rectangular microstrip patch on a uniaxial substrate
NASA Astrophysics Data System (ADS)
Wong, Kin-Lu; Row, Jeen-Sheen; Kuo, Chih-Wen; Huang, Kuang-Chih
1993-04-01
Effects of uniaxial anisotropy in the substrate on the complex resonant frequency of the microstrip patch antenna are investigated in terms of an integral equation formulation. The complex resonant frequency of the microstrip patch antenna is calculated by using Galerkin's method in solving the integral equation. The sinusoidal functions are selected as the basis functions, which show fast numerical convergence. Numerical results also indicate that both the resonant frequency and the half-power bandwidth are increased due to the positive uniaxial anisotropy and, on the other hand, decreased due to the negative uniaxial anisotropy.
Like cures like: a neuroimmunological model based on electromagnetic resonance.
Shahabi, Shahram; Kasariyans, Aditya; Noorbakhsh, Farshid
2013-12-01
Recent investigations have pointed to the production of characteristic electromagnetic (EM) waves in highly diluted sterile filtrates of different microorganisms and their associated DNA molecules. Analysis of these diluted solutions that are prepared using methods almost identical to the way that homeopathic medicines are prepared has pointed to the existence of nanostructures capable of emitting EM waves. Combining these results with findings that point to the interaction of EM waves with sensory nerves with subsequent activation of homeostatic efferent pathways, we propose a model to describe mechanisms underlying the effects of homeopathic remedies. THE MODEL: Living cells and tissues are capable of generating EM waves in their physiological conditions. When a cell deviates from its physiological state, in addition to normal EM emissions, it starts to produce EM waves with altered characteristics. According to our model, the main cause of the therapeutic effects of homeopathic remedies is the occurrence of resonance between the non-physiological EM waves of the patient and extremely low-frequency EM waves produced by nanostructures present in the homeopathic remedy. Resonance occurs if the frequency and amplitude characteristics of the patient's non-physiological EM waves and those produced by nanostructures of the applied homeopathic remedy are similar. Once resonance occurs, stimulation of the patient's sensory neurons, which are sensitized due to inflammation of any origin, leads to triggering of different regulatory mechanisms, including the activation of descending antinociceptive and/or cholinergic anti-inflammatory pathways, which leads to the restoration of homeostasis.
Ultracold bosons in the vicinity of a narrow resonance: Shallow dimer and recombination
Pricoupenko, Ludovic; Jona-Lasinio, Mattia
2011-12-15
The different resonant regimes that can be achieved by using a magnetic Feshbach resonance are analyzed with a separable two-channel model. Emphasis is put on the case of narrow resonances in a region of intermediate detuning where a shallow dimer exists and an approximate law including the background scattering length for the three-body recombination rate is derived.
Electron bounce resonance heating in a bumpy cylinder
Chen, G.L.
1984-10-01
In bumpy cylinder geometry, the electrons are classified into trapped and passing particles. The interaction between a wave near the electron bounce frequency and the electrons is studied both numerically and analytically for the appropriate parameters of ELMO Bumpy Torus-Scale (EBT-S). It is shown that coupling of the waves to the electron bounce motion parallel to the magnetic field can lead to heating of those electrons near the passing/trapped boundary in velocity space. The stochastic threshold condition is eE/sub 0/k/sub 0//m..omega../sub b//sup 2/ approx. = 0.1. For this mechanism, it is found that the wave energy density required to induce stochastic heating in EBT by rf (in the frequency range of ion cyclotron resonance heating (ICRH)) is about an order of magnitude more than that estimated on the basis of cold plasma wave theory. It is hypothesized that this discrepancy would disappear when the thermal correction to the wave propagation and the effects of collisions and toroidicity are included. We also suggest that the bounce resonance can enhance the electron cyclotron resonance heating (ECRH) efficiency in an EBT-like heating scheme.
Creating a zero-order resonator using an optical surface transformation
Sun, Fei; Ge, Xiaochen; He, Sailing
2016-01-01
A novel zero-order resonator has been designed by an optical surface transformation (OST) method. The resonator proposed here has many novel features. Firstly, the mode volume can be very small (e.g. in the subwavelength scale). Secondly, the resonator is open (no reflecting walls are utilized) and resonant effects can be found in a continuous spectrum (i.e. a continuum of eigenmodes). Thirdly, we only need one homogenous medium to realize the proposed resonator. The shape of the resonator can be a ring structure of arbitrary shape. In addition to the natural applications (e.g. optical storage) of an optical resonator, we also suggest some other applications of our novel optical open resonator (e.g. power combination, squeezing electromagnetic energy in the free space). PMID:26888359
Noise control using a plate radiator and an acoustic resonator
NASA Technical Reports Server (NTRS)
Pla, Frederic G. (Inventor)
1996-01-01
An active noise control subassembly for reducing noise caused by a source (such as an aircraft engine) independent of the subassembly. A noise radiating panel is bendably vibratable to generate a panel noise canceling at least a portion of the source noise. A piezoceramic actuator plate is connected to the panel. A front plate is spaced apart from the panel and the first plate, is positioned generally between the source noise and the panel, and has a sound exit port. A first pair of spaced-apart side walls each generally abut the panel and the front plate so as to generally enclose a front cavity to define a resonator.
LASER BEAMS AND RESONATORS: On formation of a partially coherent beam in a stable-resonator laser
NASA Astrophysics Data System (ADS)
Suvorov, A. A.
2010-05-01
A new method involving the expansion of the field coherence function in partially coherent modes — the eigensolutions of the problem for the second-order coherence function in a stable resonator — is proposed for the theoretical description of the process of multimode laser beam formation. The method for solving the problem for arbitrary partially coherent modes is formulated and the expressions for these modes are derived in the general form. The characteristics of the fundamental partially coherent mode, which coincides with the coherence function of a Gaussian partially coherent beam, are analysed in detail. The partially coherent modes are shown to possess two spatial scales — the effective radius and the coherence radius, which makes them a convenient tool for solving the problem of generation of a partially coherent beam. It is found that the unambiguous relation between the characteristics of partially coherent modes and the stable-resonator parameters is achieved by involving into consideration not only the process of the beam formation by the resonator mirrors but also the process of interaction of radiation with the active laser medium.
Engineering a resonant nanocoating for an optical refractive index sensor
NASA Astrophysics Data System (ADS)
Bialiayeu, A.; Ianoul, A.; Albert, J.
2014-03-01
We proposing to boost the performance of refractive index sensors based on the tilted fiber Bragg grating (TFBG) structure by resonant coupling of small spherical nanoparticles to the TFBG resonances. The optimal choice of nanoparticle parameters is discussed.
Magnetic resonance force microscopy with a paramagnetic probe
Berman, G. P.; Gorshkov, V. N.; Tsifrinovich, V. I.
2017-04-01
Here, we consider theoretically extension of magnetic resonance force microscopy (MRFM) replacing a ferromagnetic probe on a cantilever tip (CT) with a paramagnetic one (PMRFM). The dynamics of the interaction between the paramagnetic probe and a local magnetic moment in a sample is analyzed, using a quasi-classical approach. We show that the application of a proper sequence of electromagnetic pulses provides a significant deflection of the CT from the initial equilibrium position. Periodic application of these sequences of pulses results in quasi-periodic CT deflections from the equilibrium, which can be used for detection of the magnetic moment in a sample.
Magnetic resonance force microscopy with a paramagnetic probe
NASA Astrophysics Data System (ADS)
Berman, G. P.; Gorshkov, V. N.; Tsifrinovich, V. I.
2017-04-01
We consider theoretically extension of magnetic resonance force microscopy (MRFM) replacing a ferromagnetic probe on a cantilever tip (CT) with a paramagnetic one (PMRFM). The dynamics of the interaction between the paramagnetic probe and a local magnetic moment in a sample is analyzed, using a quasi-classical approach. We show that the application of a proper sequence of electromagnetic pulses provides a significant deflection of the CT from the initial equilibrium position. Periodic application of these sequences of pulses results in quasi-periodic CT deflections from the equilibrium, which can be used for detection of the magnetic moment in a sample.
Coherent Raman scattering with incoherent light for a multiply resonant mixture: Theory
NASA Astrophysics Data System (ADS)
Kirkwood, Jason C.; Ulness, Darin J.; Stimson, Michael J.; Albrecht, A. C.
1998-02-01
The theory for coherent Raman scattering (CRS) with broadband incoherent light is presented for a multiply resonant, multicomponent mixture of molecules that exhibits simultaneous multiple resonances with the frequencies of the driving fields. All possible pairwise hyperpolarizability contributions to the signal intensity are included in the theoretical treatment-(resonant-resonant, resonant-nonresonant, and nonresonant-nonresonant correlations between chromophores) and it is shown how the different types of correlations manifest themselves as differently behaved components of the signal intensity. The Raman resonances are modeled as Lorentzians in the frequency domain, as is the spectral density of the incoherent light. The analytic results for this multiply resonant mixture are presented and applied to a specific binary mixture. These analytic results will be used to recover frequencies and dephasing times in a series of experiments on multiply resonant mixtures.
NASA Astrophysics Data System (ADS)
Ghal-Eh, N.; Koohi-Fayegh, R.; Hamidi, S.
2007-06-01
The resonance absorption filter technique has been used to determine the thermal/epithermal neutron flux. The main idea in this technique is to use an element with a high and essentially singular resonance in the neutron absorption cross section as a filter surrounding a miniature-type lithium glass scintillator. The count with and without the filter surrounding the detector gives the number of resonance-energy neutrons. Some preliminary results and a comparison with the MCNP code are shown.
A highly integrated FPGA-based nuclear magnetic resonance spectrometer
NASA Astrophysics Data System (ADS)
Takeda, Kazuyuki
2007-03-01
The digital circuits required for a nuclear magnetic resonance (NMR) spectrometer, including a pulse programmer, a direct digital synthesizer, a digital receiver, and a PC interface, have been built inside a single chip of the field-programmable gate-array (FPGA). By combining the FPGA chip with peripheral analog components, a compact, laptop-sized homebuilt spectrometer has been developed, which is capable of a rf output of up to 400 MHz with amplitude-, phase-, frequency-, and pulse-modulation. The number of rf channels is extendable up to three without further increase in size.
A highly integrated FPGA-based nuclear magnetic resonance spectrometer.
Takeda, Kazuyuki
2007-03-01
The digital circuits required for a nuclear magnetic resonance (NMR) spectrometer, including a pulse programmer, a direct digital synthesizer, a digital receiver, and a PC interface, have been built inside a single chip of the field-programmable gate-array (FPGA). By combining the FPGA chip with peripheral analog components, a compact, laptop-sized homebuilt spectrometer has been developed, which is capable of a rf output of up to 400 MHz with amplitude-, phase-, frequency-, and pulse-modulation. The number of rf channels is extendable up to three without further increase in size.
Single-electron measurements with a micromechanical resonator
NASA Astrophysics Data System (ADS)
Polkinghorne, R. E. S.; Milburn, G. J.
2001-10-01
A mechanical electroscope based on a change in the resonant frequency of a cantilever one micron in size in the presence of charge has recently been fabricated. We derive the decoherence rate of a charge superposition during measurement with such a device using a master equation theory adapted from quantum optics. We also investigate the information produced by such a measurement, using a quantum trajectory approach. Such instruments could be used in mesoscopic electronic systems, and future solid-state quantum computers, so it is useful to know how they behave when used to measure quantum superpositions of charge.
Hyper-Parametric Oscillations in a Whispering Gallery Mode Fluorite Resonator
NASA Technical Reports Server (NTRS)
Savchenkov, Anatoliy; Strekalov, Dmitry; Mohageg, Makan; Ilchenko, Vladimir; Matsko, Andrey; Maleki, Lute
2004-01-01
This viewgraph presentation summarizes the hyper-parametric oscillations observations of the fluorite resonator. The reporters have observed various nonlinear effects in ultra-high Q crystalline whispering gallery mode (WGM) resonators. In particular, it was demonstrated a low threshold optical hyper-parametric oscillations in a high-Q (Q=1010) CaF2 WGM resonator. The oscillations result from the resonantly enhanced four-wave-mixing occurring due to Kerr nonlinearity of the material.
Development of a Hydrogen Gas Sensor Using a Double Saw Resonator System at Room Temperature
Yunusa, Zainab; Hamidon, Mohd Nizar; Ismail, Alyani; Isa, Maryam Mohd; Yaacob, Mohd Hanif; Rahmanian, Saeed; Ibrahim, Siti Azlida; Shabaneh, Arafat A.A
2015-01-01
A double SAW resonator system was developed as a novel method for gas sensing applications. The proposed system was investigated for hydrogen sensing. Commercial Surface Acoustic Wave (SAW) resonators with resonance frequencies of 433.92 MHz and 433.42 MHz were employed in the double SAW resonator system configuration. The advantages of using this configuration include its ability for remote measurements, and insensitivity to vibrations and other external disturbances. The sensitive layer is composed of functionalized multiwalled carbon nanotubes and polyaniline nanofibers which were deposited on pre-patterned platinum metal electrodes fabricated on a piezoelectric substrate. This was mounted into the DSAWR circuit and connected in parallel. The sensor response was measured as the difference between the resonance frequencies of the SAW resonators, which is a measure of the gas concentration. The sensor showed good response towards hydrogen with a minimum detection limit of 1%. PMID:25730480
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.
Propagation of narrow laser beams in a resonantly absorbing medium
Petrushevich, Yu V; Starostin, Andrei N
2000-03-31
The propagation of a narrow laser beam in a resonantly absorbing medium is analysed. Qualitatively different patterns of the dynamics of a radiation pulse travelling in a medium (depending on conditions of the problem) were obtained by a real three-dimensional nonstationary numerical simulation. The diffraction spreading of a pulse, its compression due to self-focusing, and chaotic beam splitting caused by the development of instability were observed. The simulation results are compared with the experimental data published in the literature. A qualitative agreement is obtained with the observations and conclusions made earlier. (nonlinear optical phenomena and devices)
A 10kW series resonant converter design, transistor characterization, and base-drive optimization
NASA Technical Reports Server (NTRS)
Robson, R.; Hancock, D.
1981-01-01
Transistors are characterized for use as switches in resonant circuit applications. A base drive circuit to provide the optimal base drive to these transistors under resonant circuit conditions is developed and then used in the design, fabrication and testing of a breadboard, spaceborne type 10 kW series resonant converter.
Sato, T; Yokoyama, H; Ohya, H; Kamada, H
1999-08-01
A method for electrically detected magnetic resonance (EDMR) measurement at different ESR frequencies under a constant alternating magnetic field has been established wherein the accurate relationship between EDMR signal intensity (from a photoexcited silicon crystal and a silicon diode) and a resonant frequency of 300 to 900 MHz (UHF band) was systematically clarified. EDMR signal intensity from a photoexcited silicon crystal against a resonant frequency fitted the curve of y = a(1 - e(-bx)) well, which approached a constant value at higher frequencies. The increase in the EDMR signal intensity from the silicon diode at higher resonant frequencies was smaller than that from the photoexcited silicon crystal. The difference can be explained by the influence of the skin effect; i.e., the microwaves do not penetrate deep into a highly conductive sample at higher frequencies. EDMR signal intensities of samples vs microwave power were measured at 890 MHz. The EDMR signal intensity from the silicon diode continued to increase as the microwave power was increased, while the signal intensity from the photoexcited silicon crystal saturated within the range. The difference can be similarly explained: due to the skin effect, the microwaves gradually penetrate into the silicon diode as the power increases, so that even when saturation has been reached outside, the microwave field inside the diode does not reach the saturation level. Copyright 1999 Academic Press.
Particle manipulation by a non-resonant acoustic levitator
NASA Astrophysics Data System (ADS)
Andrade, Marco A. B.; Pérez, Nicolás; Adamowski, Julio C.
2015-01-01
We present the analysis of a non-resonant acoustic levitator, formed by an ultrasonic transducer and a concave reflector. In contrast to traditional levitators, the geometry presented herein does not require the separation distance between the transducer and the reflector to be a multiple of half wavelength. The levitator behavior is numerically predicted by applying a numerical model to calculate the acoustic pressure distribution and the Gor'kov theory to obtain the potential of the acoustic radiation force that acts on a levitated particle. We also demonstrate that levitating particles can be manipulated by controlling the reflector position while maintaining the transducer in a fixed position.
Particle manipulation by a non-resonant acoustic levitator
Andrade, Marco A. B.; Pérez, Nicolás; Adamowski, Julio C.
2015-01-05
We present the analysis of a non-resonant acoustic levitator, formed by an ultrasonic transducer and a concave reflector. In contrast to traditional levitators, the geometry presented herein does not require the separation distance between the transducer and the reflector to be a multiple of half wavelength. The levitator behavior is numerically predicted by applying a numerical model to calculate the acoustic pressure distribution and the Gor'kov theory to obtain the potential of the acoustic radiation force that acts on a levitated particle. We also demonstrate that levitating particles can be manipulated by controlling the reflector position while maintaining the transducer in a fixed position.
Resonant generation of internal waves on a model continental slope.
Zhang, H P; King, B; Swinney, Harry L
2008-06-20
We study internal wave generation in a laboratory model of oscillating tidal flow on a continental margin. Waves are found to be generated only in a near-critical region where the slope of the bottom topography matches that of internal waves. Fluid motion with a velocity an order of magnitude larger than that of the forcing occurs within a thin boundary layer above the bottom surface. The resonant wave is unstable because of strong shear; Kelvin-Helmholtz billows precede wave breaking. This work provides a new explanation for the intense boundary flows on continental slopes.
NASA Astrophysics Data System (ADS)
de Visser, P. J.; Goldie, D. J.; Diener, P.; Withington, S.; Baselmans, J. J. A.; Klapwijk, T. M.
2014-01-01
In a superconductor, absorption of photons with an energy below the superconducting gap leads to redistribution of quasiparticles over energy and thus induces a strong nonequilibrium quasiparticle energy distribution. We have measured the electrodynamic response, quality factor, and resonant frequency of a superconducting aluminium microwave resonator as a function of microwave power and temperature. Below 200 mK, both the quality factor and resonant frequency decrease with increasing microwave power, consistent with the creation of excess quasiparticles due to microwave absorption. Counterintuitively, above 200 mK, the quality factor and resonant frequency increase with increasing power. We demonstrate that the effect can only be understood by a nonthermal quasiparticle distribution.
A versatile pulse programmer for pulsed nuclear magnetic resonance spectroscopy.
NASA Technical Reports Server (NTRS)
Tarr, C. E.; Nickerson, M. A.
1972-01-01
A digital pulse programmer producing the standard pulse sequences required for pulsed nuclear magnetic resonance spectroscopy is described. In addition, a 'saturation burst' sequence, useful in the measurement of long relaxation times in solids, is provided. Both positive and negative 4 V trigger pulses are produced that are fully synchronous with a crystal-controlled time base, and the pulse programmer may be phase-locked with a maximum pulse jitter of 3 ns to the oscillator of a coherent pulse spectrometer. Medium speed TTL integrated circuits are used throughout.
Noise control zone for a periodic ducted Helmholtz resonator system.
Cai, Chenzhi; Mak, Cheuk Ming
2016-12-01
This paper presents a theoretical study of the dispersion characteristics of sound wave propagation in a periodic ducted Helmholtz resonator (HR) system. The predicted result fits well with a numerical simulation using a finite element method. This study indicates that for the same system, no matter how many HRs are connected or what the periodic distance is, the area under average transmission loss T L¯ curves is always the same. The broader the noise attenuation band, the lower the peak attenuation amplitude. A noise control zone compromising the attenuation bandwidth or peak amplitude is proposed for noise control optimization.
Method of fabricating a whispering gallery mode resonator
NASA Technical Reports Server (NTRS)
Savchenkov, Anatoliy A. (Inventor); Matkso, Andrey B. (Inventor); Iltchenko, Vladimir S. (Inventor); Maleki, Lute (Inventor)
2011-01-01
A method of fabricating a whispering gallery mode resonator (WGMR) is provided. The WGMR can be fabricated from a particular material, annealed, and then polished. The WGMR can be repeatedly annealed and then polished. The repeated polishing of the WGMR can be carried out using an abrasive slurry. The abrasive slurry can have a predetermined, constant grain size. Each subsequent polishing of the WGMR can use an abrasive slurry having a grain size that is smaller than the grain size of the abrasive slurry of the previous polishing iteration.
System-size resonance in a binary attractor neural network.
de la Casa, M A; Korutcheva, E; Parrondo, J M R; de la Rubia, F J
2005-09-01
System size resonance (SSR) is a phenomenon in which the response of a system is optimal for a certain finite size, but poorer as the size goes to zero or infinity. In order to show SSR effects in binary attractor neural networks, we study the response of a network, in the ferromagnetic phase, to an external, time-dependent stimulus. Under the presence of such a stimulus, the network shows SSR, as is demonstrated by the measure of the signal amplification both analytically and by simulation.
Storing Optical Information as a Mechanical Excitation in a Silica Optomechanical Resonator
NASA Astrophysics Data System (ADS)
Fiore, Victor; Yang, Yong; Kuzyk, Mark C.; Barbour, Russell; Tian, Lin; Wang, Hailin
2011-09-01
We report the experimental demonstration of storing optical information as a mechanical excitation in a silica optomechanical resonator. We use writing and readout laser pulses tuned to one mechanical frequency below an optical cavity resonance to control the coupling between the mechanical displacement and the optical field at the cavity resonance. The writing pulse maps a signal pulse at the cavity resonance to a mechanical excitation. The readout pulse later converts the mechanical excitation back to an optical pulse. The storage lifetime is determined by the relatively long damping time of the mechanical excitation.
Regenerative feedback resonant circuit
Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.
2014-09-02
A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.
Teaching the Concept of Resonance with the Help of a Classical Guitar
NASA Astrophysics Data System (ADS)
Kasar, M. Kaan; Yurumezoglu, Kemal; Sengoren, Serap Kaya
2012-12-01
Resonance refers to the vibrations of larger amplitude that are produced under the effect of a harmonic driving force. Although resonance is an essential concept behind many events happening in nature, students usually have difficulty in learning and explaining the phenomenon. Various demonstrations are carried out in physics classes to clarify the concept of resonance.2-6
Hodological Resonance, Hodological Variance, Psychosis, and Schizophrenia: A Hypothetical Model
Birkett, Paul Brian Lawrie
2011-01-01
Schizophrenia is a disorder with a large number of clinical, neurobiological, and cognitive manifestations, none of which is invariably present. However it appears to be a single nosological entity. This article considers the likely characteristics of a pathology capable of such diverse consequences. It is argued that both deficit and psychotic symptoms can be manifestations of a single pathology. A general model of psychosis is proposed in which the informational sensitivity or responsivity of a network (“hodological resonance”) becomes so high that it activates spontaneously, to produce a hallucination, if it is in sensory cortex, or another psychotic symptom if it is elsewhere. It is argued that this can come about because of high levels of modulation such as those assumed present in affective psychosis, or because of high levels of baseline resonance, such as those expected in deafferentation syndromes associated with hallucinations, for example, Charles Bonnet. It is further proposed that schizophrenia results from a process (probably neurodevelopmental) causing widespread increases of variance in baseline resonance; consequently some networks possess high baseline resonance and become susceptible to spontaneous activation. Deficit symptoms might result from the presence of networks with increased activation thresholds. This hodological variance model is explored in terms of schizo-affective disorder, transient psychotic symptoms, diathesis-stress models, mechanisms of antipsychotic pharmacotherapy and persistence of genes predisposing to schizophrenia. Predictions and implications of the model are discussed. In particular it suggests a need for more research into psychotic states and for more single case-based studies in schizophrenia. PMID:21811475
Biological Effects and Safety in Magnetic Resonance Imaging: A Review
Hartwig, Valentina; Giovannetti, Giulio; Vanello, Nicola; Lombardi, Massimo; Landini, Luigi; Simi, Silvana
2009-01-01
Since the introduction of Magnetic Resonance Imaging (MRI) as a diagnostic technique, the number of people exposed to electromagnetic fields (EMF) has increased dramatically. In this review, based on the results of a pioneer study showing in vitro and in vivo genotoxic effects of MRI scans, we report an updated survey about the effects of non-ionizing EMF employed in MRI, relevant for patients’ and workers’ safety. While the whole data does not confirm a risk hypothesis, it suggests a need for further studies and prudent use in order to avoid unnecessary examinations, according to the precautionary principle. PMID:19578460
Ground state of a resonantly interacting Bose gas
Diederix, J. M.; Heijst, T. C. F. van; Stoof, H. T. C.
2011-09-15
We show that a two-channel mean-field theory for a Bose gas near a Feshbach resonance allows for an analytic computation of the chemical potential, and therefore the universal constant {beta}, at unitarity. To improve on this mean-field theory, which physically neglects condensate depletion, we study a variational Jastrow ansatz for the ground-state wave function and use the hypernetted-chain approximation to minimize the energy for all positive values of the scattering length. We also show that other important physical quantities such as Tan's contact and the condensate fraction can be directly obtained from this approach.
Increasing the pumping efficiency of a resonant microwave stroage cavity
NASA Astrophysics Data System (ADS)
Baraev, S. V.; Korovin, O. P.
1980-11-01
A theoretical analysis shows that it is possible to improve the efficiency of pumping of a microwave-energy accumulation system by the use of a resonant accumulator whose coefficient of coupling, beta, with the transmission line significantly exceeds unity. It is found that for beta = 10 the maximum efficiency of pumping is 0.75; for beta = 100, the maximum efficiency attains the limiting value of 0.82. The accumulation time corresponding to the maximum pumping efficiency is of the order of 0.001-0.1 sec, and a pulse power increase of 50-75 dB is attained compared to pumping oscillator power.
Pairing and condensation in a resonant Bose-Fermi mixture
NASA Astrophysics Data System (ADS)
Fratini, Elisa; Pieri, Pierbiagio
2010-05-01
We study by diagrammatic means a Bose-Fermi mixture, with boson-fermion coupling tuned by a Fano-Feshbach resonance. For increasing coupling, the growing boson-fermion pairing correlations progressively reduce the boson condensation temperature and make it eventually vanish at a critical coupling. Such quantum critical point depends very weakly on the population imbalance and, for vanishing boson densities, coincides with that found for the polaron-molecule transition in a strongly imbalanced Fermi gas, thus bridging two quite distinct physical systems.
Baryon Resonances from a Novel Fat-Link Fermion Action
W. Melnitchouk; S. Bilson-Thompson; F. D. R. Bonnet; P. D. Coddington; F. X. Lee; D. B. Leinweber; A. G. Williams; J. M. Zanotti; J. B. Zhang
2001-07-01
We present first results for masses of positive and negative parity excited baryons in lattice QCD using an O(a{sup 2}) improved gluon action and a Fat Link Irrelevant Clover (FLIC) fermion action in which only the irrelevant operators are constructed with fat links. The results are in agreement with earlier calculations of N* resonances using improved actions and exhibit a clear mass splitting between the nucleon and its chiral partner, even for the Wilson fermion action. The results also indicate a splitting between the lowest J{sup P}=1/2{sup -} states for the standard nucleon interpolating fields.
Racetrack resonator as a loss measurement platform for photonic components
Jones, Adam M.; DeRose, Christopher T.; Lentine, Anthony L.; Starbuck, Andrew; Pomerene, Andrew T. S.; Norwood, Robert A.
2015-10-27
This work represents the first complete analysis of the use of a racetrack resonator to measure the insertion loss of efficient, compact photonic components. Beginning with an in-depth analysis of potential error sources and a discussion of the calibration procedure, the technique is used to estimate the insertion loss of waveguide width tapers of varying geometry with a resulting 95% confidence interval of 0.007 dB. Furthermore, the work concludes with a performance comparison of the analyzed tapers with results presented for four taper profiles and three taper lengths.
Bulk and surface sensitivity of a resonant waveguide grating imager
NASA Astrophysics Data System (ADS)
Orgovan, Norbert; Kovacs, Boglarka; Farkas, Eniko; Szabó, Bálint; Zaytseva, Natalya; Fang, Ye; Horvath, Robert
2014-02-01
We report the assessment of the sensitivity of a microplate-compatible resonant waveguide grating imager. The sensitivity to bulk refractive index changes was determined using a serial dilution of glycerol solution with the help of a refractometer. The surface sensitivity was examined using layer-by-layer polyelectrolyte films in conjunction with optical waveguide lightmode spectroscopy and characterized by the binding of acetazolamide to immobilized carbonic anhydrase under microfluidics. The results suggest that the imager has a limit of detection down to 2.2 × 10-6 for refractive index change and 0.078 ng/cm2 for the adsorbed mass.
Characterization of a Pulsed HF Optical Resonance Transfer Laser.
1982-10-01
AD-A 124 708 CHARACTERIZATION OF A PULSED HIE OPTICAL RESONANCE I TRANSFE R LASER(U ) AIR FORCE INST OF TECH WRIGHT -PATTERSON AFA O H SCHOOL OF...these valves failed and the third leaked and had to be replaced. All three needle valves were replaced by stainless steel which should function well...use in an HP environment). The He feed (see figure 7) to the reference cell is controlled by a stainless steel needle valve (N) and a brass bellows
Nonlinear microwave photon occupancy of a driven resonator strongly coupled to a transmon qubit
NASA Astrophysics Data System (ADS)
Suri, B.; Keane, Z. K.; Bishop, Lev S.; Novikov, S.; Wellstood, F. C.; Palmer, B. S.
2015-12-01
We measure photon occupancy in a thin-film superconducting lumped element resonator coupled to a transmon qubit at 20 mK and find a nonlinear dependence on the applied microwave power. The transmon-resonator system was operated in the strong dispersive regime, where the ac Stark shift (2 χ ) due to a single microwave photon present in the resonator was larger than the linewidth (Γ ) of the qubit transition. When the resonator was coherently driven at 5.474 325 GHz, the transition spectrum of the transmon at 4.982 GHz revealed well-resolved peaks, each corresponding to an individual photon number-state of the resonator. From the relative peak heights we obtain the occupancy of the photon states and the average photon occupancy n ¯ of the resonator. We observe a nonlinear variation of n ¯ with the applied drive power Prf for n ¯<5 and compare our results to numerical simulations of the system-bath master equation in the steady state, as well as to a semiclassical model for the resonator that includes the Jaynes-Cummings interaction between the transmon and the resonator. We find good quantitative agreement using both models and analysis reveals that the nonlinear behavior is principally due to shifts in the resonant frequency caused by a qubit-induced Jaynes-Cummings nonlinearity.
Resonant Optomechanics with a Vibrating Carbon Nanotube and a Radio-Frequency Cavity
NASA Astrophysics Data System (ADS)
Ares, N.; Pei, T.; Mavalankar, A.; Mergenthaler, M.; Warner, J. H.; Briggs, G. A. D.; Laird, E. A.
2016-10-01
In an optomechanical setup, the coupling between cavity and resonator can be increased by tuning them to the same frequency. We study this interaction between a carbon nanotube resonator and a radio-frequency tank circuit acting as a cavity. In this resonant regime, the vacuum optomechanical coupling is enhanced by the dc voltage coupling the cavity and the mechanical resonator. Using the cavity to detect the nanotube's motion, we observe and simulate interference between mechanical and electrical oscillations. We measure the mechanical ring down and show that further improvements to the system could enable the measurement of mechanical motion at the quantum limit.
Resonant Optomechanics with a Vibrating Carbon Nanotube and a Radio-Frequency Cavity.
Ares, N; Pei, T; Mavalankar, A; Mergenthaler, M; Warner, J H; Briggs, G A D; Laird, E A
2016-10-21
In an optomechanical setup, the coupling between cavity and resonator can be increased by tuning them to the same frequency. We study this interaction between a carbon nanotube resonator and a radio-frequency tank circuit acting as a cavity. In this resonant regime, the vacuum optomechanical coupling is enhanced by the dc voltage coupling the cavity and the mechanical resonator. Using the cavity to detect the nanotube's motion, we observe and simulate interference between mechanical and electrical oscillations. We measure the mechanical ring down and show that further improvements to the system could enable the measurement of mechanical motion at the quantum limit.
If It's Resonance, What is Resonating?
ERIC Educational Resources Information Center
Kerber, Robert C.
2006-01-01
The phenomenon under the name "resonance," which, is based on the mathematical analogy between mechanical resonance and the behavior of wave functions in quantum mechanical exchange phenomena was described. The resonating system does not have a structure intermediate between those involved in the resonance, but instead a structure which is further…
Phonon counting and intensity interferometry of a nanomechanical resonator.
Cohen, Justin D; Meenehan, Seán M; MacCabe, Gregory S; Gröblacher, Simon; Safavi-Naeini, Amir H; Marsili, Francesco; Shaw, Matthew D; Painter, Oskar
2015-04-23
In optics, the ability to measure individual quanta of light (photons) enables a great many applications, ranging from dynamic imaging within living organisms to secure quantum communication. Pioneering photon counting experiments, such as the intensity interferometry performed by Hanbury Brown and Twiss to measure the angular width of visible stars, have played a critical role in our understanding of the full quantum nature of light. As with matter at the atomic scale, the laws of quantum mechanics also govern the properties of macroscopic mechanical objects, providing fundamental quantum limits to the sensitivity of mechanical sensors and transducers. Current research in cavity optomechanics seeks to use light to explore the quantum properties of mechanical systems ranging in size from kilogram-mass mirrors to nanoscale membranes, as well as to develop technologies for precision sensing and quantum information processing. Here we use an optical probe and single-photon detection to study the acoustic emission and absorption processes in a silicon nanomechanical resonator, and perform a measurement similar to that used by Hanbury Brown and Twiss to measure correlations in the emitted phonons as the resonator undergoes a parametric instability formally equivalent to that of a laser. Owing to the cavity-enhanced coupling of light with mechanical motion, this effective phonon counting technique has a noise equivalent phonon sensitivity of 0.89 ± 0.05. With straightforward improvements to this method, a variety of quantum state engineering tasks using mesoscopic mechanical resonators would be enabled, including the generation and heralding of single-phonon Fock states and the quantum entanglement of remote mechanical elements.
Resonance hard radiation in a gas-loaded FEL
Gevorgian, L.A.
1995-12-31
The process of induced radiation under the condition when the relativistic beam oscillation frequency coincides with the plasma frequency of the FEL filling gas, is investigated. Such a resonance results in a giant enhancement of interaction between electrons and photons providing high gain in the hard FEL frequency region. Meanwhile the spectralwidth of the spontaneous radiation is broadened significantly. A method is proposed for maintaining the synchronism between the electron oscillation frequency and the medium plasma frequency, enabling to transform the electron energy into hard radiation with high efficiency.
Coherence properties of a doubly resonant monolithic optical parametric oscillator
NASA Technical Reports Server (NTRS)
Nabors, C. D.; Yang, S. T.; Day, T.; Byer, R. L.
1990-01-01
A doubly resonant optical parametric oscillator (DRO) pumped with the second harmonic of a narrow-linewidth Nd:YAG laser is described. The linewidth of the DRO signal was less than 13 kHz, the DRO was shown to generate a phase-locked subharmonic of the pump at degeneracy, and the signal and the idler were shown to be mutually coherent with the pump and to be phase-anticorrelated with each other away from degeneracy. The signal-idler heterodyne linewidth was 500 Hz, and pump phase modulation was shown to transfer to the DRO phase at degeneracy.
A 58 sq m Passive Resonant Ring Laser Gyroscope
NASA Astrophysics Data System (ADS)
Shaw, G. L.; Simmons, B. J.
1984-01-01
A 7.62 x 7.62 m Passive Ring Resonator Laser Gyro (PRRLG) is analyzed. Each element of the PRRLG is consistent with the requirements for geophysical applications, which would include precision measurements of earth rotation and polar wobble. The shot noise limit was calculated to be about 3 x 10 to the -8th ERU (tau = 1 sec), and, with a predicted transition Fourier frequency between white noise and 1/f noise at about 200 microHz, a resolution on the order of about 4 x 10 to the -10th ERU is feasible.
A resonance-free nano-film airborne ultrasound emitter
NASA Astrophysics Data System (ADS)
Daschewski, Maxim; Harrer, Andrea; Prager, Jens; Kreutzbruck, Marc; Beck, Uwe; Lange, Thorid; Weise, Matthias
2013-01-01
In this contribution we present a novel thermo-acoustic approach for the generation of broad band airborne ultrasound and investigate the applicability of resonance-free thermo-acoustic emitters for very short high pressure airborne ultrasound pulses. We report on measurements of thermo-acoustic emitter consisting of a 30 nm thin metallic film on a usual soda-lime glass substrate, generating sound pressure values of more than 140 dB at 60 mm distance from the transducer and compare the results with conventional piezoelectric airborne ultrasound transducers. Our experimental investigations show that such thermo-acoustic devices can be used as broad band emitters using pulse excitation.
a Survey of Giant Resonance Excitations with 200 Mev Protons
NASA Astrophysics Data System (ADS)
Tinsley, James Royce
The giant resonance region in ('60)Ni, ('90)Zr, ('120)Sn, and ('208)Pb has been studied using inelastic scattering of 200 MeV protons. Angular distributions were obtained for the giant quadrupole resonance, giant octupole resonance, and for the combined giant dipole and giant monopole resonance between 4 and 20 degrees. The 2(H/2PI)(omega) component of the giant hexadecapole resonance has been directly observed for the first time in ('208)Pb. In the other nuclei, upper limits on the amount of hexadecapole strength contained within the giant quadrupole resonance have been obtained. Peaks are observed in ('60)Ni and ('90)Zr that are consistent with recently reported M1 states. Discrepancies between sum rules extracted from this data and from previous work are discussed. Possible explanations include DWBA breakdown or difficulties in estimating the magnitude of the continuum. Systematics obtained for the giant resonances are compared to earlier work.
Probing a dielectric resonator acting as passive sensor through a wireless microwave link
NASA Astrophysics Data System (ADS)
Friedt, J.-M.; Boudot, R.; Martin, G.; Ballandras, S.
2014-09-01
Dielectric resonators, generally used for frequency filtering in oscillator loops, can be used as passive cooperative targets for wireless sensor applications. In the present work, we demonstrate such an approach by probing their spectral characteristics using a microwave RADAR system. The unique spectral response and energy storage capability of resonators provide unique responses allowing to separate the sensor response from clutter. Although the dielectric resonator is not designed for high temperature sensitivity, the accurate determination of the resonance frequency allows for a remote estimate of the temperature with Kelvin resolution.
Study of stochastic resonance in a quantum dot network
NASA Astrophysics Data System (ADS)
Fujino, Hiroki; Oya, Takahide
2012-10-01
This paper reports a study of stochastic resonance in a huge quantum dot network for single-electron (SE) circuits. Such circuits, which are controlled by the Coulomb blockade, are one type of next-generation information-processing device. However, they are very sensitive to noises such as thermal noise and device mismatch noise. Thus, we introduce the stochastic resonance phenomenon into the circuit to improve its noise tolerance. Stochastic resonance is a phenomenon that was discovered in the brains of living things in noisy environments and was modeled for neural networks. When the phenomenon occurs, its harnessing of noise energy makes weak signals become clear. In current research, SE devices that operate with stochastic resonance have been reported. However, signals were attenuated in particularly noisy environments. In contrast, it was reported that a huge molecular network amplified weak signals by harnessing noise energy. The report said the current-voltage characteristics of the molecular network described the Coulomb blockade under a noisy environment. Thus, a huge quantum dot network that is partly similar to a molecular network is expected to amplify the weak signal harnessing noise, when the current-voltage characteristics of the network show the Coulomb blockade. To confirm this, in this study we use the Monte Carlo method to simulate the noisy-environment operation of a quantum dot network comprising quantum dots and tunneling junctions. We observe the current-voltage characteristics of the network, when changing the network size (5×5, 10×10, and 100×100) and the noise intensity (0 K, 2 K, 5 K, and 10 K for operating temperature, and 0%, 5%, 10%, and 30% for device mismatch). As a result, we are able to observe the Coulomb blockade under the appropriate noise strength, which in this study is 5 K or less with thermal noise, and 30% with device mismatch. From the results, we conclude the network operates correctly under appropriate noise strength
A Micromachined Millimeter-Wave Cavity Resonator on Silicon and Quartz Substrates
NASA Astrophysics Data System (ADS)
Song, Ki-Jae; Yoon, Bup-Sang; Lee, Jong-Chul; Lee, Byungje; Kim, Jong-Heon; Kim, Nam-Young; Park, Jae-Yeong; Kim, Geun-Ho; Bu, Jong-Uk
2001-12-01
In this letter, a Ka-band cavity resonator using micromachining process is presented. A two-port cavity resonator is designed using the three-dimensional (3-D) design software, HP HFSS. The cavity resonator is fabricated on a Si substrate and bonded with a Quartz wafer. The resonator shows the resonant frequency of 39 GHz, the insertion loss of 4.6 dB, and the loaded quality factor (QL) and unloaded quality factor (QU) of 44.3 and 107, respectively.
Baryon resonances without quarks: A chiral soliton perspective
Karliner, M.
1987-03-01
In many processes involving low momentum transfer it is fruitful to regard the nucleon as a soliton or ''monopole-like'' configuration of the pion field. In particular, within this framework it is possible to obtain detailed predictions for pion-nucleon scattering amplitudes and for properties of baryon resonances. One can also derive model-independent linear relations between scattering amplitudes, such as ..pi..N and anti KN. A short survey of some recent results is given, including comparison with experimental data.
Nonlinear Parameter Identification of a Resonant Electrostatic MEMS Actuator.
Al-Ghamdi, Majed S; Alneamy, Ayman M; Park, Sangtak; Li, Beichen; Khater, Mahmoud E; Abdel-Rahman, Eihab M; Heppler, Glenn R; Yavuz, Mustafa
2017-05-13
We experimentally investigate the primary superharmonic of order two and subharmonic of order one-half resonances of an electrostatic MEMS actuator under direct excitation. We identify the parameters of a one degree of freedom (1-DOF) generalized Duffing oscillator model representing it. The experiments were conducted in soft vacuum to reduce squeeze-film damping, and the actuator response was measured optically using a laser vibrometer. The predictions of the identified model were found to be in close agreement with the experimental results. We also identified the noise spectral density of process (actuation voltage) and measurement noise.
Two-band combined model of a resonant tunneling diode
Abramov, I. I. Goncharenko, I. A.; Kolomeitseva, N. V.
2007-11-15
A two-band combined model of a resonant tunneling diode, based on the semiclassical and quantum mechanical (the wave function formalism) approaches is proposed. The main specific feature of this model is the possibility of taking into account the interaction between different classical or quantum mechanical device regions with simultaneous consideration of the {gamma}-X intervalley scattering. It is shown that this model gives satisfactory agreement with the experimental data on the current-voltage characteristics and allows explanation of the plateau region in these characteristics within the stationary model.
Acoustic force measurement in a dual-temperature resonant chamber
NASA Technical Reports Server (NTRS)
Robey, Judith L.; Trinh, Eugene H.; Wang, Taylor G.
1987-01-01
The acoustic radiation force was measured for a dual-temperature resonant chamber. This rectangular chamber has its long dimension approximately 8.5 times the square cross-sectional dimension, and the opposite ends are at widely different temperatures. Force profiles were obtained for two hot end temperatures of 520 C and 760 C, while the cool end remained at approximately room temperature. Force magnitudes as high as 17 dyn for a sample 1.2 cm in diameter at 760 C and at 162-dB input level were measured.
A wide linear range surface plasmon resonance biosensor
NASA Astrophysics Data System (ADS)
Sun, Zhanliang; He, Yonghong; Shao, Yonghong; Guo, Jihua
2006-09-01
A new surface plasmon resonance (SPR) sensor based on polarization interferometry and angle modulation is presented. Its feature is that it can provide the same sensitivity in a wide refractive index (RI) range. Moreover, the sensitivity ofthis SPR sensor is insensitive to the thickness of gold films over about 5 mu. Experimental results show that its resolution in an integration time of 0.5 second is 1.7 × 10 -7 refractive index units (RIU). It demonstrates great potential to be commercialized and widely applied in biological research.
A New Tissue Resonator Indenter Device and Reliability Study
Jia, Ming; Zu, Jean W.; Hariri, Alireza
2011-01-01
Knowledge of tissue mechanical properties is widely required by medical applications, such as disease diagnostics, surgery operation, simulation, planning, and training. A new portable device, called Tissue Resonator Indenter Device (TRID), has been developed for measurement of regional viscoelastic properties of soft tissues at the Bio-instrument and Biomechanics Lab of the University of Toronto. As a device for soft tissue properties in-vivo measurements, the reliability of TRID is crucial. This paper presents TRID’s working principle and the experimental study of TRID’s reliability with respect to inter-reliability, intra-reliability, and the indenter misalignment effect as well. PMID:22346623
Scarred resonances and steady probability distribution in a chaotic microcavity
Lee, Soo-Young; Rim, Sunghwan; Kim, Chil-Min; Ryu, Jung-Wan; Kwon, Tae-Yoon
2005-12-15
We investigate scarred resonances of a stadium-shaped chaotic microcavity. It is shown that two components with different chirality of the scarring pattern are slightly rotated in opposite ways from the underlying unstable periodic orbit, when the incident angles of the scarring pattern are close to the critical angle for total internal reflection. In addition, the correspondence of emission pattern with the scarring pattern disappears when the incident angles are much larger than the critical angle. The steady probability distribution gives a consistent explanation about these interesting phenomena and makes it possible to expect the emission pattern in the latter case.
Stellar dynamics around a massive black hole - II. Resonant relaxation
NASA Astrophysics Data System (ADS)
Sridhar, S.; Touma, Jihad R.
2016-06-01
We present a first-principles theory of resonant relaxation (RR) of a low-mass stellar system orbiting a more massive black hole (MBH). We first extend the kinetic theory of Gilbert to include the Keplerian field of a black hole of mass M•. Specializing to a Keplerian stellar system of mass M ≪ M•, we use the orbit-averaging method of Sridhar & Touma to derive a kinetic equation for RR. This describes the collisional evolution of a system of N ≫ 1 Gaussian rings in a reduced 5-dim space, under the combined actions of self-gravity, 1 post-Newtonian (PN) and 1.5 PN relativistic effects of the MBH and an arbitrary external potential. In general geometries, RR is driven by both apsidal and nodal resonances, so the distinction between scalar RR and vector RR disappears. The system passes through a sequence of quasi-steady secular collisionless equilibria, driven by irreversible two-ring correlations that accrue through gravitational interactions, both direct and collective. This correlation function is related to a `wake function', which is the linear response of the system to the perturbation of a chosen ring. The wake function is easier to appreciate, and satisfies a simpler equation, than the correlation function. We discuss general implications for the interplay of secular dynamics and non-equilibrium statistical mechanics in the evolution of Keplerian stellar systems towards secular thermodynamic equilibria, and set the stage for applications to the RR of axisymmetric discs in Paper III.
A new method for calculation of Efimov resonances
NASA Astrophysics Data System (ADS)
Masnou-Seeuws, Francoise; Blandon, Juan; Kokoouline, Viatcheslav
2007-06-01
The recent observation of Efimov resonances in a cold gas [1] opens a new field. We have developed a method to calculate accurately the positions, widths and wave functions of three-body resonances. The calculations combine the hyperspherical adiabatic approach [2] and the slow variable discretization method of Ref.[3]. A sine grid basis set is used with a mapping procedure to introduce a variable grid step in the hyper-radius and in the two hyperangles; moreover, a complex absorbing potential is introduced. The method can be used to determine accurately both the short range and the long range wavefunctions. It has been checked on a model potential and compared with a R-matrix method [4] which necessitates a much larger basis set: the two calculations are in good agreement. [1] T. Kraemer et al., Nature 440, 315 (2006), [2] V.Kokoouline and F.Masnou-Seeuws, Phys. Rev. A 73, 012702 (2006), [3] O.I.Tolstikhin, S.Watanabe, and M.Matsuzawa, J. Phys. B: At. Mol. Opt. Phys. 29, L389 (1996), [4] E. Nielsen, H. Suno, and B. D. Esry, Phys. Rev. A 66, 012705 (2002).
Optical-Fiber-Illuminated Response of a Superconducting Microwave Resonator Below 1 K
NASA Astrophysics Data System (ADS)
Voigt, Kristen; Hertzberg, J. B.; Dutta, S. K.; Hoffman, J. E.; Grover, J. A.; Lee, J.; Solano, P.; Budoyo, R. P.; Ballard, C.; Anderson, J. R.; Lobb, C. J.; Rolston, S. L.; Wellstood, F. C.
As a step towards building a hybrid quantum system that couples superconducting elements to neutral atoms trapped on a tapered optical nanofiber, we have studied how the presence of the fiber dielectric and light scattered from a fiber affect the response of a translatable thin-film lumped-element superconducting Al microwave resonator that is cooled to 15 mK. The resonator has a resonance frequency of about 6 GHz, a quality factor Q 2 x 105, and is mounted inside a 3D Al superconducting cavity. An optical fiber is tapered to a 60 um diameter and passes through two small holes in the 3D cavity such that it sits near the resonator. The 3D cavity is mounted on an x-z piezo-translation stage that allows us to change the relative position of the thin-film resonator and fiber. When the resonator is brought closer to the fiber, the resonance frequency decreases slightly due to the presence of the fiber dielectric. When 200 uW of 780 nm light is sent through the fiber, about 100 pW/mm is Rayleigh-scattered from the fiber. This causes a position-dependent illumination of the resonator, affecting its resonance frequency and Q. We compare our results to a model of the resonator response that includes the generation, diffusion, and recombination of quasiparticles in the resonator and find that the frequency response allows us to track the position of the fiber to within 10 um.
NASA Technical Reports Server (NTRS)
Folkestad, K.; Troim, J.
1974-01-01
The report presents observations obtained in a swept frequency experiment conducted in a mother-daughter rocket flight at auroral latitudes. The discussion is essentially restricted to the possible interpretation of the experimental signal structures noted at and in the vicinity of a resonance frequency where signal components apparently are generated by nonlinear mechanisms. Various resonance frequencies have been considered in attempts to identify this multichannel response frequency. It is concluded that of all the possibilities invoked, the best consistency is provided by identifying the frequency concerned with the cone resonance frequency demonstrated experimentally in the case of a laboratory plasma by Fisher and Gould (1971).
NASA Astrophysics Data System (ADS)
Asjad, Muhammad; Vitali, David
2014-02-01
A deterministic scheme for generating a macroscopic superposition state of a nanomechanical resonator is proposed. The nonclassical state is generated through a suitably engineered dissipative dynamics exploiting the optomechanical quadratic interaction with a bichromatically driven optical cavity mode. The resulting driven dissipative dynamics can be employed for monitoring and testing the decoherence processes affecting the nanomechanical resonator under controlled conditions.
A Secular Resonance Between Iapetus and the Giant Planets
NASA Astrophysics Data System (ADS)
Cuk, Matija; Dones, Henry C. Luke; Nesvorny, David; Walsh, Kevin J.
2017-06-01
Iapetus is the outermost of the regular satellites of Saturn, and its origin and evolution present a number of unsolved problems. From the point of view of orbital dynamics, it is remarkable that Iapetus has a large inclination (8 degrees) and a significantly smaller eccentricity (0.03), contrary to the pattern expected if its orbit was excited by encounters between Saturn and other planets early in the Solar System's history (Nesvorny et al, 2014). Here we report our long-term numerical integrations of Iapetus's orbit that show multi-Myr oscillations of Iapetus's eccentricity with an amplitude on the order of 0.01. We find that the basic argument causing this behavior is the sum of the longitude of pericenter and the longitude of the node of Iapetus, with a 0.3 Myr period. This argument appears to be in resonance with the period of the g5 mode in the eccentricity and perihelion of Saturn. We find that our nominal solution, including Saturn's oblateness, Titan, Iapetus and all four giant planets, shows librations of the argument: ǎrpi_Iapetus - ǎrpi_g5 + \\Omega_Iapetus - \\Omega_SaturnEq, where ǎrpi and \\Omega are the longitudes of pericenters and nodes, respectively, and \\Omega_SaturnEq is Saturn's equinox. While planetary perturbations are crucial in generating the g5 mode and therefore maintaining this resonance, we find that Iapetus is affected by the planets only indirectly, with the Sun being the dominant direct perturber. The libration is stable for tens of Myr for the nominal rate of Saturn's pole precession (French et al, 2017), and appears stable indefinitely if we assume a secular resonance between Saturn's node and the secular mode g18 (Ward and Hamilton, 2004; Hamilton and Ward, 2004). We will present the implication of this resonance for the origin of Iapetus's orbit and the dynamical history of Saturn's system. This research is funded by NASA Outer Planets Research Program award NNX14AO38G. References: French, R. G., McGhee-French, C. A