Showing papers on "Resonance published in 2003"
TL;DR: In this article, a narrow charmonium-like state produced in the exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi has been observed, which has a mass of 3872.0+/-0.6(stat)+/- 0.5(syst) MeV.
Abstract: We report the observation of a narrow charmoniumlike state produced in the exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has a mass of 3872.0+/-0.6(stat)+/-0.5(syst) MeV, a value that is very near the M(D0)+M(D(*0)) mass threshold. The results are based on an analysis of 152M B-Bmacr; events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider. The signal has a statistical significance that is in excess of 10sigma.
1,294 citations
TL;DR: Solid state and liquid phase NMR shifts obtained by magic angle spinning with external referencing agree with those measured using typical solution NMR hardware with the sample tube aligned with the applied field as long as magnetic susceptibility corrections and solvent shifts are taken into account.
759 citations
TL;DR: In this article, a microring resonator with increased resonance slopes is proposed by introducing two partially reflecting elements implemented by waveguide offsets, which can greatly enhance the sensitivity of the sensor.
Abstract: Photonic microresonators have great potential in the application of highly sensitive sensors due to high Q-factor resonances and steep slopes between zero and unity transmission. A microring resonator with increased resonance slopes is proposed by introducing two partially reflecting elements implemented by waveguide offsets. This configuration produces a Fano-resonant line shape and can greatly enhance the sensitivity of the sensor. Polystyrene microring resonators were fabricated by the nanoimprinting technique, and the optical spectra were measured in glucose solutions of different concentrations. The shift in resonant wavelength and variation of the normalized transmitted intensity are linearly related to the concentration of the glucose solution.
490 citations
TL;DR: In this paper, the mechanical resonance of a single ZnO nanobelt, induced by an alternative electric field, was studied by in situ transmission electron microscopy, and two fundamental resonance modes have been observed corresponding to two orthogonal transverse vibration directions, showing the versatile applications of nanobelts as nanocantilevers and nanoresonators.
Abstract: The mechanical resonance of a single ZnO nanobelt, induced by an alternative electric field, was studied by in situ transmission electron microscopy. Due to the rectangular cross section of the nanobelt, two fundamental resonance modes have been observed corresponding to two orthogonal transverse vibration directions, showing the versatile applications of nanobelts as nanocantilevers and nanoresonators. The bending modulus of the ZnO nanobelts was measured to be ∼52 GPa and the damping time constant of the resonance in a vacuum of 5×10−8 Torr was ∼1.2 ms and quality factor Q=500.
480 citations
TL;DR: The theory and data for magnetoelectric (ME) coupling at electromechanical resonance (EMR) in the layered samples were investigated in this article, and the results showed that the ME voltage coefficient at resonance increases by a factor of 40 compared to low frequency values.
Abstract: Magnetoelectric interactions in bilayers of magnetostrictive and piezoelectric phases are mediated by mechanical deformation. This work is concerned with the theory and companion data for magnetoelectric (ME) coupling at electromechanical resonance (EMR) in the layered samples. Estimated ME voltage coefficient versus frequency profiles for nickel, cobalt, or lithium ferrite and lead zirconate titanate (PZT) predict a giant ME effect at EMR with the highest coupling expected for cobalt ferrite-PZT. There is excellent agreement between the theory and data for layered nickel ferrite-PZT; the ME voltage coefficient at resonance increases by a factor of 40 compared to low frequency values. Similar measurements on layered ferromagnetic alloy-PZT and bulk ferrite-PZT reveal even a stronger EMR assisted enhancement in ME coupling.
398 citations
TL;DR: A long-range dynamic interaction between ferromagnetic films separated by normal-metal spacers is reported, which is communicated by nonequilibrium spin currents.
Abstract: A long-range dynamic interaction between ferromagnetic films separated by normal-metal spacers is reported, which is communicated by nonequilibrium spin currents. It is measured by ferromagnetic resonance and explained by an adiabatic spin-pump theory. In such a resonance the spin-pump mechanism of spatially separated magnetic moments leads to an appreciable increase in the resonant linewidth when the resonance fields are well apart, and results in a dramatic linewidth narrowing when the resonant fields approach each other.
340 citations
TL;DR: In this article, the maximum induced magnetoelectric voltage at resonance was ∼10 Vp/Oe, which was ∼102 times higher than previous reports at subresonant frequencies.
Abstract: We have found that laminate composites consisting of longitudinally magnetized magnetostrictive Terfenol-D and longitudinally poled piezoelectric Pb(Zr,Ti)O3 layers have dramatically enhanced magnetoelectric effects when driven near resonance. The maximum induced magnetoelectric voltage at resonance was ∼10 Vp/Oe, which is ∼102 times higher than previous reports at subresonant frequencies.
318 citations
TL;DR: The production of a pure sample of up to 3 x 10(5) optically trapped molecules from a Fermi gas of 6Li atoms using a Stern-Gerlach selection technique that efficiently removes all trapped atoms from the atom-molecule mixture.
Abstract: We report on the production of a pure sample of up to 3 x 10(5) optically trapped molecules from a Fermi gas of 6Li atoms. The dimers are formed by three-body recombination near a Feshbach resonance. For purification, a Stern-Gerlach selection technique is used that efficiently removes all trapped atoms from the atom-molecule mixture. The behavior of the purified molecular sample shows a striking dependence on the applied magnetic field. For very weakly bound molecules near the Feshbach resonance, the gas exhibits a remarkable stability with respect to collisional decay.
291 citations
TL;DR: In this paper, the authors discuss resonance and threshold phenomena in low-energy electron collisions with molecules and clusters, and the theoretical description of electron-molecule collisions generally requires an adequate description of electronic, vibrational and rotational degrees of freedom.
Abstract: Publisher Summary This chapter discusses resonance and threshold phenomena in low-energy electron collisions with molecules and clusters. Low-energy collisions of electrons with atoms and molecules are among the most important elementary processes in gaseous environments such as discharges, arcs, gas lasers, gaseous dielectrics and the earth's atmosphere. The dynamics behavior of low-energy electron-molecule collisions is discussed. The dynamical behavior of slow electrons traversing gases is to a large extent determined by two effects: the energy dependent evolution of the scattering phases for the relevant partial waves and the influence of temporary negative ion states (resonances). Some aspects of resonance and threshold phenomena are discussed. The theoretical description of electron-molecule collisions generally requires an adequate description of electronic, vibrational and rotational degrees of freedom. However, if the typical collision time is short compared to the rotational period, the molecule can be treated as having a fixed orientation during the collision process, and the result for the cross-section can be averaged over orientations. Treatment of vibrational dynamics is usually more important and more challenging to the theory. In the electron energy region important for applications, many inelastic processes such as vibrational excitation and dissociative electron attachment are driven by negative-ion resonances. The theoretical description of vibrational dynamics in these cases is usually based on the nonlocal complex potential describing the nuclear motion in the intermediate negative-ion state.
262 citations
TL;DR: In this article, the authors studied long-lived resonances in hexagonally shaped dielectric resonators in order to gain insight into the physics of a class of microcrystal lasers.
Abstract: We study long-lived resonances (lowest-loss modes) in hexagonally shaped dielectric resonators in order to gain insight into the physics of a class of microcrystal lasers. Numerical results on resonance positions and lifetimes, near-field intensity patterns, far-field emission patterns, and effects of rounding of corners are presented. Most features are explained by a semiclassical approximation based on pseudointegrable ray dynamics and boundary waves. The semiclassical model is also relevant for other microlasers of polygonal geometry.
236 citations
TL;DR: In this article, a review of double resonance Raman spectroscopy is presented, where non-zone center phonon modes in solids can be observed in the double-resonance Raman spectrum, in which weak Raman signals appear in a wide frequency region and their combination or overtone modes can be assigned.
Abstract: A review of double resonance Raman spectroscopy is presented. Non-zone centre phonon modes in solids can be observed in the double resonance Raman spectra, in which weak Raman signals appear in a wide frequency region and their combination or overtone modes can be assigned. By changing the excitation laser energy, we can derive the phonon dispersion relations of a single nanotube.
TL;DR: In this paper, the position of the ν 1 mode of trans-polyacetylene using a vibronic model for resonance Raman scattering and compared the results with the measured positions of the 1150 cm−1 mode for diamond samples on different substrates and found a very good agreement.
TL;DR: In this article, the HARPSS process was used to fabricate high quality factor (Q) single crystal silicon (SCS) in-plane capacitive beam resonators with sub-100 nm to submicron transduction gaps.
Abstract: This paper reports on the fabrication and characterization of high-quality factor (Q) single crystal silicon (SCS) in-plane capacitive beam resonators with sub-100 nm to submicron transduction gaps using the HARPSS process. The resonating element is made of single crystal silicon while the drive and sense electrodes are made of trench-refilled polysilicon, yielding an all-silicon capacitive microresonator. The fabricated SCS resonators are 20-40 /spl mu/m thick and have self-aligned capacitive gaps. Vertical gaps as small as 80 nm in between 20 /spl mu/m thick silicon structures have been demonstrated in this work. A large number of clamped-free and clamped-clamped beam resonators were fabricated. Quality factors as high as 177000 for a 19 kHz clamped-free beam and 74000 for an 80 kHz clamped-clamped beam were measured under 1 mtorr vacuum. Clamped-clamped beam resonators were operated at their higher resonance modes (up to the fifth mode); a resonance frequency of 12 MHz was observed for the fifth mode of a clamped-clamped beam with the fundamental mode frequency of 0.91 MHz. Electrostatic tuning characteristics of the resonators have been measured and compared to the theoretical values. The measured Q values of the clamped-clamped beam resonators are within 20% of the fundamental thermoelastic damping limits (Q/sub TED/) obtained from finite element analysis.
TL;DR: In this article, optical absorption and electro absorption studies on the lead-iodide-based natural quantum-well perovskite-type crystals with different well width (C6H13NH3)2(CH3NH3),m−1PbmI3m+1 with decreasing well thickness, m, the resonance energies of the lowest energy excitons shift to higher energy due to the increase of the bandgap.
TL;DR: In this paper, the optical properties of mixed clusters Ni/Ag, Co/Ag and Ni/Au of 2-5 nm in diameter, produced by laser vaporization and embedded in an alumina matrix, are investigated.
Abstract: Optical properties of mixed clusters Ni/Ag, Co/Ag, and Ni/Au of 2-5 nm in diameter, produced by laser vaporization and embedded in an alumina matrix, are investigated. The first part is devoted to (Ni x Ag 1 - x ) n clusters whose photoabsorption spectra reveal a surface plasmon resonance, damped, broadened, and blue-shifted as compared to pure silver clusters. For a given mean size, a blueshift of the resonance band as well as a damping and broadening with increasing nickel proportion is observed, in good qualitative agreement with classical predictions, assuming a Ni-core/Ag-shell geometry. This core-shell structure is confirmed by low energy ion spectroscopy measurements showing that the cluster surface is essentially composed of silver. For a given composition, the size evolution of the plasmon band consists of a damping and broadening with decreasing size whereas no clear shift is noticed. Although the classical predictions, including the surface scattering limited mean free path contribution of the conduction electrons in the silver shell, account well for the size effects, inhomogeneous effects (size, shape, and local porosity) also contribute to the broadening and damping of the resonance in experiment. The second part concerns the optical properties of (Co 0 . 5 Ag 0 . 5 ) n and (Ni 0 . 5 Au 0 . 5 ) n clusters. The size evolution of the optical properties of (Co 0 . 5 Ag 0 . 5 ) n clusters is similar to that of (Ni 0 . 5 Ag 0 . 5 ) n clusters, with in addition, a weak blueshift of the resonance with decreasing size. As for the (Ni 0 . 5 Au 0 . 5 ) n clusters, their optical spectra do not display a marked resonance. The comparison with a core-shell model including a size dependent damping constant in the gold or silver shell gives a good understanding of these features for the two systems Co/Ag and Ni/Au.
TL;DR: Scale invariance of resonance frequencies, unusually strong orthogonality properties of resonance modes, and a two-dimensional phenomenon of "twin" spectra are reported.
Abstract: Resonant behavior of dielectric objects occurs at certain frequencies for which the object permittivity is negative and the free-space wavelength is large in comparison with the object dimensions. Unique physical features of these resonances are studied and a novel technique for the calculation of resonance values of permittivity, and hence resonance frequencies, is proposed. Scale invariance of resonance frequencies, unusually strong orthogonality properties of resonance modes, and a two-dimensional phenomenon of "twin" spectra are reported. The paper concludes with brief discussions of optical controllability of these resonances in semiconductor nanoparticles and a plausible, electrostatic resonance based, mechanism for nucleation and formation of ball lightning.
TL;DR: In this article, the hydrogen storage capacity of a small amount of carbon nanotubes (CNTs) mounted on an ultrathin resonator by a manipulator is measured from the resonant frequency change.
Abstract: Ultrathin single-crystalline silicon cantilevers with a thickness of 170 nm as a resonating sensor are applied to mass sensing. The hydrogen storage capacity of a small amount of carbon nanotubes (CNTs), which were mounted on an ultrathin resonator by a manipulator, is measured from the resonant frequency change. The resonator is annealed in ultrahigh vacuum to clean the surface and increase the quality factor, and exposed to oxygen gas to oxidize the surface for long-term stability. The resonator can be electrostatically actuated, and the vibration is measured by a laser Doppler vibrometer in ultrahigh vacuum. The mass of the CNTs is determined by the difference of resonant frequencies before and after mounting the CNTs, and the hydrogen storage capacity is determined from the frequency change after exposure to high-pressure hydrogen as well. The obtained hydrogen storage capacitance is 1.6%–6.0%. The available mass resolution and the achieved stability of the resonance of the 170-nm-thick resonator are below 10−18 g and 5 Hz/days, respectively.
TL;DR: In this article, the Stark shift was used to tune the excitonic energy levels of a single quantum dot into resonance with a narrow-band laser line at 4.2 K. Relative changes in transmission can be detected this way down to one part per million.
Abstract: Excitonic interband optical transitions within single InAs self-assembled quantum dots have been directly observed in a transmission experiment at 4.2 K. Using Stark shift, the excitonic energy levels of a single quantum dot are tuned into resonance with a narrow-band laser line. The Stark shift is also modulated at low frequencies. Relative changes in transmission can be detected this way down to one part per million. The oscillator strength as well the homogeneous linewidth of the transition is obtained.
21 Jul 2003-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: A second high current accelerator of 400 kV has been installed at the underground laboratory of Gran Sasso, called LUNA II as discussed by the authors, which measured the absolute energy, energy spread, and long-term energy stability.
Abstract: A second high current accelerator of 400 kV has been installed at the underground laboratory of Gran Sasso, called LUNA II. We describe this new facility as well as measurements of the proton beam characteristics: absolute energy, energy spread, and long-term energy stability. The absolute energy was determined to a precision of 7300 eV at Ep ¼ 130–400 keV using the energy of the capture g-ray transition of 12 Cðp;gÞ 13 N as well as resonance energies at Ep ¼ 309–389 keV of 23 Naðp;gÞ 24 Mg; 26 Mgðp;gÞ 27 Al; and 25 Mgðp;gÞ 26 Al: The resonance studies led to a proton energy
TL;DR: In this article, the authors used an average ellipsoid approach, including a size-induced broadening of the Drude part of the dielectric function, to model the near-infrared absorption caused by the excitation of surface plasmons.
Abstract: Window samples with a LaB6 nanoparticle-doped polymer laminate were tested for their performances in the reduction of solar heat gain. The near-infrared absorption, caused by the excitation of surface plasmons, was modeled using an average ellipsoid approach, including a size-induced broadening of the Drude part of the dielectric function. The resonance positions are well reproduced by this method and the size effect broadens the bulk resonance to an extent observed in the sample spectra. Additional broadening and spectral features observed in the absorption of the samples are attributed to shape and orientation effects.
TL;DR: In this paper, a wire-guided, gravity-driven jet apparatus is described that produces optically stable thin films of liquids flowing at rates suitable for high repetition rate spectroscopy.
Abstract: A wire-guided, gravity-driven jet apparatus is described that produces optically stable thin films of liquids flowing at rates suitable for high repetition rate spectroscopy. Unlike conventional free-flowing jets, the design works well for low viscosity solvents including water and aqueous solutions of proteins. The construction of the wire guide, jet nozzle, and flow system is described. A stable water film whose thickness can be varied from 6 to 100 μm is demonstrated that has been employed in resonance Raman and femtosecond transient absorption experiments.
TL;DR: In this article, the uv resonance raman spectroscopy was applied to the in-situ characterization of catalyst synthesis and catalytic reactions, and it was shown that the raman effect greatly enhances the signal strength of the isolated transition metal ions.
05 Oct 2003
TL;DR: In this article, a device structure eliminating the spurious modes arising from lateral standing Lamb waves is presented, and the operating principle behind the device is described with the use of a simple model.
Abstract: In this paper a device structure eliminating the spurious modes arising from lateral standing Lamb waves is presented. The operating principle behind the device is described with the use of a simple model. Experimental results of ZnO and AlN based resonators in SMR configuration are given. Laser interferometer measurements are presented that confirm applicability of the idea.
TL;DR: Theoretical prediction of a frequency-independent transport time around a sharp atomic resonance is verified and the effect of the residual velocity of the atoms at long times is observed, reducing strongly the diffusion constant.
Abstract: We study the diffusive propagation of multiply scattered light in an optically thick cloud of cold rubidium atoms illuminated by a quasiresonant laser beam. In the vicinity of a sharp atomic resonance, the energy transport velocity of the scattered light is almost 5 orders of magnitude smaller than the vacuum speed of light, reducing strongly the diffusion constant. We verify the theoretical prediction of a frequency-independent transport time around the resonance. We also observe the effect of the residual velocity of the atoms at long times.
TL;DR: In this article, an all-optical microwave frequency standard based on coherent population trapping (CPT) in 85Rb is developed, where the CPT resonances are detected by an ordinary edge-emitting diode laser in a simple optical setup.
Abstract: An all-optical microwave frequency standard based on coherent population trapping (CPT) in 85Rb is developed. The CPT resonances are detected by an ordinary edge-emitting diode laser in a simple optical setup. A buffer-gas mixture is carefully optimized to yield a narrow linewidth and a reduced temperature dependence of the resonance frequency. With the developed system we are able to measure ultranarrow optically induced hyperfine CPT resonances at <20 Hz, which is in good agreement with the linewidth calculated from experimental parameters. The frequency of an RF-signal generator has been stabilized to the CPT resonance between the two mF=0 magnetic sublevels. The relative frequency stability (square root of Allan variance) follows a slope of 3.5×10-11 τ-1/2(1 s<τ<2000 s). The best stability of 6.4×10-13 is reached at an integration time of τ=2000 s. This stability is sufficient for many high-precision applications. Frequency-shift measurements were made to evaluate the frequency dependencies on the operation parameters.
TL;DR: In this paper, an analytical model is proposed to study the nonlinear interactions between beam and cable dynamics in stayed-systems, and the effects of detuning from internal and external resonance are presented.
TL;DR: In this article, a tensorial Green's function is used to calculate the dipole exchange spectrum of quantized spin wave modes of a tangentially magnetized rectangular thin-film magnetic element.
Abstract: Dipole-exchange spectrum of quantized spin wave modes of a tangentially magnetized rectangular thin-film magnetic element is calculated using the method of tensorial Green's functions. The strong inhomogeneity of the internal bias magnetic field along the magnetization direction leads to the localization of spin wave modes either at the edges (exchange localization) or at the center (dipolar localization) of the element. The mode intensity distributions along the other in-plane direction are determined by the dipolar boundary conditions and have the usual cosinusoidal form. The approximate theory developed in the paper gives a quantitative description of the resonance fields and qualitative description of the spatial distributions of quantized spin wave modes in a thin square permalloy element (in plane sizes $50\ifmmode\times\else\texttimes\fi{}50\ensuremath{\mu}{\mathrm{m}}^{2},$ thickness 0.1 \ensuremath{\mu}m) recently observed by space-resolved Kerr spectroscopy. The theory shows also that the mode localization in this case (in the element center) is of the dipolar nature.
TL;DR: The experimental evidence and characterization of "vibrational resonance" in a bistable vertical cavity laser are reported, which shows up in the dynamics of the polarized laser emission as a resonance in the low-frequency response and signal-to-noise ratio.
Abstract: The experimental evidence and characterization of ``vibrational resonance'' in a bistable vertical cavity laser are reported. The system is driven by two periodic forcings, with frequencies differing by several orders and studied in the case of both symmetrical and asymmetrical quasipotentials. The phenomenon shows up in the dynamics of the polarized laser emission as a resonance in the low-frequency response and signal-to-noise ratio, depending on the amplitude of an applied high-frequency modulation. The possibility to use the phenomenon for low-level detection is experimentally demonstrated.
TL;DR: In this article, an enhanced infrared absorption was demonstrated for anthracene coating polar dielectric nanoparticles of silicon carbide and aluminum oxide and the results have implications for near field microscopy, the characterization of nano-optical devices, and chemical sensing.
Abstract: Enhanced infrared absorption is demonstrated for anthracene coating polar dielectric nanoparticles of silicon carbide and aluminum oxide. An enhancement factor greater than 100 was measured near the surface of silicon carbide particles. This is the result of the enhanced optical fields at the surface of the particles when illuminated at the surface phonon resonance frequencies. This phonon resonance effect is analogous to plasmon resonance that is the basis of surface enhanced infrared absorption and surface enhanced Raman scattering. The results have implications for near-field microscopy, the characterization of nano-optical devices, and chemical sensing. In addition, the methodology used for surface phonon analysis of particles is useful for simulating comet and interstellar dust spectra.
TL;DR: The mobile state is trapped at a corner site where the O(3C)H group is formed and may coherently be explained in terms of mobility of the exciton (O(2-)(4C)* or--after ionization--of the corresponding electron hole O-(4C) along the edge where it was created.
Abstract: Surface anions on edges (4-coordinated = 4C) and on corners (3-coordinated = 3C) of cubic MgO nanoparticles exhibit UV resonance absorptions around 5.5 and 4.6 eV, respectively. After monochromatic excitation of either site the electron paramagnetic resonance (EPR) spectrum exhibits exclusively signal components related to 3-coordinated O- radicals ( , electron hole centers), which are perfectly bleached by H2 addition. The disappearance of the EPR signal components is paralleled by a depletion of the UV resonance absorption of the 3-coordinated O2- only and the appearance of one single band in the OH stretching region of the IR spectrum. Obviously the sites of UV excitation and subsequent UV induced surface reaction with H2 are not the same. This may coherently be explained in terms of mobility of the exciton ( )* or − after ionization − of the corresponding electron hole along the edge where it was created. Finally the mobile state is trapped at a corner site where the O3CH group is formed.