WorldWideScience

Sample records for cavity resonators

  1. Seismic resonances of acoustic cavities

    Science.gov (United States)

    Schneider, F. M.; Esterhazy, S.; Perugia, I.; Bokelmann, G.

    2016-12-01

    The goal of an On-Site Inspection (OSI) is to clarify at a possible testsite whether a member state of the Comprehensive nuclear Test Ban Treaty (CTBT)has violated its rules by conducting a underground nuclear test. Compared toatmospheric and underwater tests underground nuclear explosions are the mostdifficult to detect.One primary structural target for the field team during an OSI is the detectionof an underground cavity, created by underground nuclear explosions. Theapplication of seismic-resonances of the cavity for its detection has beenproposed in the CTBT by mentioning "resonance seismometry" as possibletechnique during OSIs. We modeled the interaction of a seismic wave-field withan underground cavity by a sphere filled with an acoustic medium surrounded byan elastic full space. For this setting the solution of the seismic wave-fieldcan be computed analytically. Using this approach the appearance of acousticresonances can be predicted in the theoretical calculations. Resonance peaksappear in the spectrum derived for the elastic domain surrounding the acousticcavity, which scale in width with the density of the acoustic medium. For lowdensities in the acoustic medium as for an gas-filled cavity, the spectralpeaks become very narrow and therefore hard to resolve. The resonancefrequencies, however can be correlated to the discrete set of eigenmodes of theacoustic cavity and can thus be predicted if the dimension of the cavity isknown. Origin of the resonance peaks are internal reverberations of wavescoupling in the acoustic domain and causing an echoing signal that couples outto the elastic domain again. In the gas-filled case the amplitudes in timedomain are very low.Beside theoretical considerations we seek to find real data examples fromsimilar settings. As example we analyze a 3D active seismic data set fromFelsőpetény, Hungary that has been conducted between 2012 and 2014 on behalf ofthe CTBTO. In the subsurface of this area a former clay mine is

  2. Digital Cavity Resonance Monitor, alternative method of measuring cavity microphonics

    International Nuclear Information System (INIS)

    Tomasz Plawski; G. Davis; Hai Dong; J. Hovater; John Musson; Thomas Powers

    2005-01-01

    As is well known, mechanical vibration or microphonics in a cryomodule causes the cavity resonance frequency to change at the vibration frequency. One way to measure the cavity microphonics is to drive the cavity with a Phase Locked Loop. Measurement of the instantaneous frequency or PLL error signal provides information about the cavity microphonic frequencies. Although the PLL error signal is available directly, precision frequency measurements require additional instrumentation, a Cavity Resonance Monitor (CRM). The analog version of such a device has been successfully used for several cavity tests [1]. In this paper we present a prototype of a Digital Cavity Resonance Monitor designed and built in the last year. The hardware of this instrument consists of an RF downconverter, digital quadrature demodulator and digital processor motherboard (Altera FPGA). The motherboard processes received data and computes frequency changes with a resolution of 0.2 Hz, with a 3 kHz output bandwidth

  3. The CEBAF separator cavity resonance control system

    International Nuclear Information System (INIS)

    M. Wissmann; C. Hovater; A. Guerra; T. Plawski

    2005-01-01

    The CEBAF energy upgrade will increase the maximum beam energy from 6 GeV to 12 GeV available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three halls. The resulting increase in RF separator cavity gradient and subsequent increase in RF power needed for these higher energies will require the cavities to have active resonance control. Currently, at the present 4 to 6 GeV energies, the cavities are tuned mechanically and then stabilized with Low Conductivity Water (LCW) which is maintained at a constant temperature of 95 Fahrenheit. This approach is no longer feasible and an active resonance control system that controls both water temperature and flow has been designed and built. The system uses a commercial PLC with embedded PID controls to regulate water temperature and flow to the cavities. The system allows the operator to remotely adjust temperature/flow and consequently cavity resonance for the full range of beam energies. Ultimately, closed loop control will be maintained by monitoring each cavity's reflected power. This paper describes this system

  4. The CEBAF Separator Cavity Resonance Control System

    CERN Document Server

    Wissmann, Mark J; Hovater, Curt; Plawski, Tomasz

    2005-01-01

    The CEBAF energy upgrade from 6 GeV to 12GeV will increase the range of beam energies available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three experimental halls. Consequently with the increase in RF separator cavity gradient needed for the higher energies, RF power will also increase requiring the cavities to have active resonance control. At the 6 GeV energy, the cavities are tuned mechanically and then stabilized with Low Conductivity Water (LCW), which is maintained at constant temperature of 95o Fahrenheit. This is no longer feasible and an active resonance control system, that controls both water temperature and flow has been built. The system uses a commercial PLC with embedded PID controls to control water temperature and flow to the cavities. The system allows the operator to remotely adjust temperature/flow and consequently cavity resonance for the full range of beam energies. Ultimately closed loop control will be maintained by monit...

  5. Shear Layer Dynamics in Resonating Cavity Flows

    National Research Council Canada - National Science Library

    Ukeiley, Lawrence

    2004-01-01

    .... The PIV data was also combined with the surface pressure measurements through the application of the Quadratic Stochastic Estimation procedure to provide time resolved snapshots of the flow field. Examination of these results indicate the strong pumping action of the cavity regardless of whether resonance existed and was used to visualize the large scale structures interacting with the aft wall.

  6. Tunable cavity resonator including a plurality of MEMS beams

    Science.gov (United States)

    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.

  7. Dynamic Color Displays Using Stepwise Cavity Resonators.

    Science.gov (United States)

    Chen, Yiqin; Duan, Xiaoyang; Matuschek, Marcus; Zhou, Yanming; Neubrech, Frank; Duan, Huigao; Liu, Na

    2017-09-13

    High-resolution multicolor printing based on pixelated optical nanostructures is of great importance for promoting advances in color display science. So far, most of the work in this field has been focused on achieving static colors, limiting many potential applications. This inevitably calls for the development of dynamic color displays with advanced and innovative functionalities. In this Letter, we demonstrate a novel dynamic color printing scheme using magnesium-based pixelated Fabry-Pérot cavities by gray scale nanolithography. With controlled hydrogenation and dehydrogenation, magnesium undergoes unique metal and dielectric transitions, enabling distinct blank and color states from the pixelated Fabry-Pérot resonators. Following such a scheme, we first demonstrate dynamic Ishihara plates, in which the encrypted images can only be read out using hydrogen as information decoding key. We also demonstrate a new type of dynamic color generation, which enables fascinating transformations between black/white printing and color printing with fine tonal tuning. Our work will find wide-ranging applications in full-color printing and displays, colorimetric sensing, information encryption and anticounterfeiting.

  8. On the exploitation of seismic resonances for cavity detection

    Science.gov (United States)

    Schneider, Felix M.; Esterhazy, Sofi; Perugia, Ilaria; Bokelmann, Götz

    2017-04-01

    We study the interaction of a seismic wave-field with a spherical acoustic gas- or fluid-filled cavity. The intention of this study is to clarify whether seismic resonances can be expected, a characteristic feature, which may help detecting cavities in the subsurface. This is important for many applications, as in particular the detection of underground nuclear explosions which are to be prohibited by the Comprehensive-Test-Ban-Treaty (CTBT). On-Site Inspections (OSI) should assure possible violation of the CTBT to be convicted after detection of a suspicious event from a nuclear explosion by the international monitoring system (IMS). One primary structural target for the field team during an OSI is the detection of cavities created by underground nuclear explosions. The application of seismic resonances of the cavity for its detection has been proposed in the CTBT by mentioning "resonance seismometry" as possible technique during OSIs. In order to calculate the full seismic wave-field from an incident plane wave that interacts with the cavity, we considered an analytic formulation of the problem. The wave-field interaction consists of elastic scattering and the wave-field interaction between the acoustic and elastic media. Acoustic resonant modes, caused by internal reflections in the acoustic cavity, show up as spectral peaks in the frequency domain. The resonant peaks are in close correlation to the eigenfrequencies of the undamped system described by the particular acoustic medium bounded in a sphere with stiff walls. The filling of the cavity could thus be determined by the observation of spectral peaks from acoustic resonances. By energy transmission from the internal oscillations back into the elastic domain and intrisic attenuation, the oscillations experience damping, resulting in a frequency shift and a limitation of the resonance amplitudes. In case of a gas-filled cavity the impedance contrast is high resulting in very narrow, high-amplitude resonances

  9. Hybrid III-V/SOI Resonant Cavity Photodetector

    DEFF Research Database (Denmark)

    Learkthanakhachon, Supannee; Taghizadeh, Alireza; Park, Gyeong Cheol

    2016-01-01

    A hybrid III-V/SOI resonant cavity photo detector has been demonstrated, which comprises an InP grating reflectorand a Si grating reflector. It can selectively detects an incident light with 1.54-µm wavelength and TM polarization.......A hybrid III-V/SOI resonant cavity photo detector has been demonstrated, which comprises an InP grating reflectorand a Si grating reflector. It can selectively detects an incident light with 1.54-µm wavelength and TM polarization....

  10. Magnetic resonance imaging of syrinx cavity

    International Nuclear Information System (INIS)

    Fukuda, Teruo; Inoue, Yuichi; Nemoto, Yutaka

    1987-01-01

    Syrinx cavity may result from a number of intramedullary tumors or non-neoplastic conditions such as Chiari malformation, trauma and meningitis. The surgical procedure to repair the syrinx is quite different between the cases with spinal cord tumor and without tumor. Therefore, it is important to determine whether syrinx is associated with tumor or not before surgery. We reviewed MR images of 26 cases with syrinx cavity; 20 of which were not associated with tumor (12 Chiari malformation, 5 trauma, 1 meningitis, 1 hydrocephalus, 1 idiopathic) and 6 of which were associated with intramedullary tumor (3 ependymoma, 2 astrocytoma, 1 hemangioendothelioma). The syrinx showed low signal in all 26 cases on T1 weighted images (SE 600/40). All 6 cases with syrinx associated with intramedullary tumor showed high intensity on T2 weighted images (SE 2000/120). On the other hand, the syrinx of 19 of 20 cases with no tumor condition showed reduced intensity on T2 weighted images. Only one post-traumatic small syrinx showed high signal. This was quite different between the cases with spinal cord tumor and without tumor. Therefore, when the syrinx cavity shows high signal on T2 weighted images, an intramedullary tumor is strongly suggested. (author)

  11. Coupled superconducting resonant cavities for a heavy ion linac

    International Nuclear Information System (INIS)

    Shepard, K.W.; Roy, A.

    1992-01-01

    A design for a superconducting niobium slow-wave accelerating structure has been explored that may have performance and cost advantages over existing technology. The option considered is an array of pairs of quarter-wave coaxial-line resonant cavities, the two elements of each pair strongly coupled through a short superconducting transmission line. In the linac formed by such an array, each paired structure is independently phased. A disadvantage of two-gap slow wave structures is that each cavity is relatively short, so that a large number of independently-phased elements is required for a linac. Increasing the number of drift tubes per cavity reduces the number of independently-phased elements but at the cost of reducing the range of useful velocity acceptance for each element. Coupling two cavities splits the accelerating rf eigenmode into two resonant modes each of which covers a portion of the full velocity acceptance range of the original, single cavity mode. Using both of these resonant modes makes feasible the use of coupled cavity pairs for a linac with little loss in velocity acceptance. (Author) 2 figs., 8 refs

  12. Whispering Gallery Mode Resonators as Optical Reference Cavities

    Science.gov (United States)

    Baumgartel, Lukas; Thompson, Rob; Strekalov, Dmitry; Grudinin, Ivan; Yu, Nan

    2011-01-01

    Highly stabilized lasers are an increasingly valuable tool for metrology. For many applications, however, existing Fabry Perot systems are too bulky and cumbersome. We are investigating the use of miniature monolithic whispering gallery mode resonators as reference cavities for laser stabilization. We seek to exploit the benefit of small size and vibration resistance by suppressing thermally induced frequency fluctuations. We have theoretically investigated the viability of using a thin-film coating to achieve temperature compensation. We have experimentally investigated an active temperature stabilization scheme based on birefringence in a crystalline resonator. We also report progress of laser locking to the resonators.

  13. Cylindrical Resonator Utilizing a Curved Resonant Grating as a Cavity Wall

    Directory of Open Access Journals (Sweden)

    Hirohito Yamada

    2012-02-01

    Full Text Available A thin-film grating on a curved substrate functions as a highly reflective and wavelength sensitive mirror for a diverging wave that has the same curvature as the substrate. In this paper we propose a cylindrical cavity surrounded by a curved resonant grating wall, and describe its resonance characteristics. Through finite-difference time-domain (FDTD simulation we have clarified that this type of cavity supports two resonance modes: one is confined by Fresnel reflection and the other by resonance reflection of the wall. We have also demonstrated that the latter mode exhibits a Q factor several orders of magnitude higher than that of the former mode.

  14. Lead salt resonant cavity enhanced detector with MEMS mirror

    Science.gov (United States)

    Felder, F.; Fill, M.; Rahim, M.; Zogg, H.; Quack, N.; Blunier, S.; Dual, J.

    2010-01-01

    We describe a tunable resonant cavity enhanced detector (RCED) for the mid-infrared employing narrow gap lead-chalcogenide (IV-VI) layers on a Si substrate. The device consists of an epitaxial Bragg reflector layer, a thin p-n+ heterojunction with PbSrTe as detecting layer and a micro-electro-mechanical system (MEMS) micromirror as second mirror. Despite the thin absorber layer the sensitivity is even higher than for a conventional detector. Tunability is achieved by changing the cavity length with a vertically movable MEMS mirror. The device may be used as miniature infrared spectrometer to cover the spectral range from 30 μm.

  15. Quasistatic Cavity Resonance for Ubiquitous Wireless Power Transfer.

    Directory of Open Access Journals (Sweden)

    Matthew J Chabalko

    Full Text Available Wireless power delivery has the potential to seamlessly power our electrical devices as easily as data is transmitted through the air. However, existing solutions are limited to near contact distances and do not provide the geometric freedom to enable automatic and un-aided charging. We introduce quasistatic cavity resonance (QSCR, which can enable purpose-built structures, such as cabinets, rooms, and warehouses, to generate quasistatic magnetic fields that safely deliver kilowatts of power to mobile receivers contained nearly anywhere within. A theoretical model of a quasistatic cavity resonator is derived, and field distributions along with power transfer efficiency are validated against measured results. An experimental demonstration shows that a 54 m3 QSCR room can deliver power to small coil receivers in nearly any position with 40% to 95% efficiency. Finally, a detailed safety analysis shows that up to 1900 watts can be transmitted to a coil receiver enabling safe and ubiquitous wireless power.

  16. Electromagnetically induced transparency with resonant nuclei in a cavity.

    Science.gov (United States)

    Röhlsberger, Ralf; Wille, Hans-Christian; Schlage, Kai; Sahoo, Balaram

    2012-02-08

    The manipulation of light-matter interactions by quantum control of atomic levels has had a profound impact on optical sciences. Such manipulation has many applications, including nonlinear optics at the few-photon level, slow light, lasing without inversion and optical quantum information processing. The critical underlying technique is electromagnetically induced transparency, in which quantum interference between transitions in multilevel atoms renders an opaque medium transparent near an atomic resonance. With the advent of high-brilliance, accelerator-driven light sources such as storage rings or X-ray lasers, it has become attractive to extend the techniques of optical quantum control to the X-ray regime. Here we demonstrate electromagnetically induced transparency in the regime of hard X-rays, using the 14.4-kiloelectronvolt nuclear resonance of the Mössbauer isotope iron-57 (a two-level system). We exploit cooperative emission from ensembles of the nuclei, which are embedded in a low-finesse cavity and excited by synchrotron radiation. The spatial modulation of the photonic density of states in a cavity mode leads to the coexistence of superradiant and subradiant states of nuclei, respectively located at an antinode and a node of the cavity field. This scheme causes the nuclei to behave as effective three-level systems, with two degenerate levels in the excited state (one of which can be considered metastable). The radiative coupling of the nuclear ensembles by the cavity field establishes the atomic coherence necessary for the cancellation of resonant absorption. Because this technique does not require atomic systems with a metastable level, electromagnetically induced transparency and its applications can be transferred to the regime of nuclear resonances, establishing the field of nuclear quantum optics.

  17. Mechanical design of RFQ resonator cavities in the 400-MHz frequency range

    International Nuclear Information System (INIS)

    Hansborough, L.D.; Potter, J.M.; Wilson, N.G.

    1981-01-01

    Many RFQ resonator-cavity design concepts have been proposed in the 400-MHz frequency range. Los Alamos has been evaluating RFQ resonator-cavity designs that provide acceptable combinations of necessary mechanical features, easy tunability and long-term stability. Four RFQ resonator test cavities have been fabricated to test rf joints between the RFQ vanes and the resonator cavity. Two of these joints (the C-seal and the rf clamp-joint) allow vane movement for tuning. These test data, and the design of the present generation of RFQ resonator cavities, are presented

  18. Regularized quasinormal modes for plasmonic resonators and open cavities

    Science.gov (United States)

    Kamandar Dezfouli, Mohsen; Hughes, Stephen

    2018-03-01

    Optical mode theory and analysis of open cavities and plasmonic particles is an essential component of optical resonator physics, offering considerable insight and efficiency for connecting to classical and quantum optical properties such as the Purcell effect. However, obtaining the dissipative modes in normalized form for arbitrarily shaped open-cavity systems is notoriously difficult, often involving complex spatial integrations, even after performing the necessary full space solutions to Maxwell's equations. The formal solutions are termed quasinormal modes, which are known to diverge in space, and additional techniques are frequently required to obtain more accurate field representations in the far field. In this work, we introduce a finite-difference time-domain technique that can be used to obtain normalized quasinormal modes using a simple dipole-excitation source, and an inverse Green function technique, in real frequency space, without having to perform any spatial integrations. Moreover, we show how these modes are naturally regularized to ensure the correct field decay behavior in the far field, and thus can be used at any position within and outside the resonator. We term these modes "regularized quasinormal modes" and show the reliability and generality of the theory by studying the generalized Purcell factor of dipole emitters near metallic nanoresonators, hybrid devices with metal nanoparticles coupled to dielectric waveguides, as well as coupled cavity-waveguides in photonic crystals slabs. We also directly compare our results with full-dipole simulations of Maxwell's equations without any approximations, and show excellent agreement.

  19. Mid-Infrared Tunable Resonant Cavity Enhanced Detectors

    Directory of Open Access Journals (Sweden)

    Hans Zogg

    2008-09-01

    Full Text Available Mid-infrared detectors that are sensitive only in a tunable narrow spectral band are presented. They are based on the Resonant Cavity Enhanced Detector (RCED principle and employing a thin active region using IV-VI narrow gap semiconductor layers. A Fabry-Pérot cavity is formed by two mirrors. The active layer is grown onto one mirror, while the second mirror can be displaced. This changes the cavity length thus shifting the resonances where the detector is sensitive. Using electrostatically actuated MEMS micromirrors, a very compact tunable detector system has been fabricated. Mirror movements of more than 3 μm at 30V are obtained. With these mirrors, detectors with a wavelength tuning range of about 0.7 μm have been realized. Single detectors can be used in mid-infrared micro spectrometers, while a detector arrangement in an array makes it possible to realize Adaptive Focal Plane Arrays (AFPA.

  20. Longitudinal and transverse electric field measurements in resonant cavities

    International Nuclear Information System (INIS)

    Tong Dechun; Chen Linfeng; Zheng Xiaoyue

    1994-01-01

    The paper presents a measuring technique for the electric field distribution of high order modes in resonant cavities. A perturbing bead-like cage made with metallic wires are developed for S-band field measurements, which can be used to detect a small electric field component in the presence of other strong electric or magnetic field components (That means high sensitivity and high directivity). In order to avoid orientation error for the cage with very high directivity, two parallel threads were used for supporting the perturbing cage. A simple mechanical set-up is described. The cage can be driven into the cavity on-axis or off-axis in any azimuth for the longitudinal and transverse electric field measurements

  1. Resonant spin wave excitations in a magnonic crystal cavity

    Science.gov (United States)

    Kumar, N.; Prabhakar, A.

    2018-03-01

    Spin polarized electric current, injected into permalloy (Py) through a nano contact, exerts a torque on the magnetization. The spin waves (SWs) thus excited propagate radially outward. We propose an antidot magnonic crystal (MC) with a three-hole defect (L3) around the nano contact, designed so that the frequency of the excited SWs, lies in the band gap of the MC. L3 thus acts as a resonant SW cavity. The energy in this magnonic crystal cavity can be tapped by an adjacent MC waveguide (MCW). An analysis of the simulated micromagnetic power spectrum, at the output port of the MCW reveals stable SW oscillations. The quality factor of the device, calculated using the decay method, was estimated as Q > 105 for an injected spin current density of 7 ×1012 A/m2.

  2. A study of nasal cavity volume by magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tosa, Yasuyoshi (Showa Univ., Tokyo (Japan). School of Medicine)

    1992-04-01

    The nasal cavity volume in 69 healthy volunteers from 8 to 23 years old (17 males and 52 females) was studied using magnetic resonance imaging (MRI). Merits of MRI such as no radiation exposure, less artifact due to bone and air and measurement of intravascular blood flow; and demerits such as contraindication in users of heart pace-makers or magnetic clips, contraindication in people with claustrophobia and influence of environmental magnetic fields must be considered. A Magunetom M10 (Siemens), a superconduction device with 1.0 Tesla magnetic flux density was used. Enhanced patterns of T[sub 1], and pulse lines were photographed at 600 msec TR (repetition time) and 19 msec TE (echo time) using SE (spin echo) and short SE (spin echo), and 3 or 4 mm slices. Photographs were made of the piriform aperture, choana, superior-middle-inferior concha including the nasal meatus, the frontal sinus, maxillary sinus, cribriform plate, and upper surface of the palate. The line connecting the maximum depression point in the nasal root and the pontomedullary junction was selected by sagittal median section, because this corresponds well with the CM (canthomeatal) line which is useful in CT (computed tomography). The transverse section of the nasal cavity volume was traced by display console with an accessory MRI device and calculated by integration of the slice width. The increase of height and body weight neared a plateau at almost 16 years, whereas increase of nasal cavity volume continued until about 20 years. Pearson's coefficient of correlation and regression line were significant. There were no significant differences in these parameters between male and female groups. Comparatively strong correlation between nasal cavity volume, and age, height and body weight was statistically evident. (author).

  3. The numerical simulation of plasma flow in cylindrical resonant cavity of microwave plasma thruster

    International Nuclear Information System (INIS)

    Tang, J.-L.; He, H.-Q; Mao, G.-W.

    2004-01-01

    Microwave Plasma Thruster (MPT) is an electro-thermal propulsive device. MPT consists of microwave generator, gas storing and supplying system, resonant cavity and accelerative nozzle. It generates free-floating plasma brought by the microwave discharge breakdown gas in the resonant cavity, and the plasma exhausted from nozzle produces thrust. MPT has prospective application in spacecraft because of its advantages of high thrust, moderate specific impulse and high efficiency. In this paper, the numerical simulation of the coupling flow field of microwave plasma in resonant cavity under different frequencies will be discussed. The results of numerical simulation are as follows: 1) When the resonant model TM 011 was used, the higher the microwave frequency was, the smaller the size of MPT. The distribution of the electromagnetic field in small cavity, however, remain unchanged. 2) When the resonant model was used, the distribution of the temperature, the pressure and the electronic density in the resonant cavity remained unchanged under different resonant frequencies. 3) When the resonant frequency was increased with a fixed pressure distribution in a small cavity, compare to the MPT with lower frequency, the gas flow rate, the microwave power and the nozzle throat diameter of MPT all decreased. 4) The electromagnetic field in the cylindrical resonant cavity for all MPT with different frequencies was disturbed by the plasma formation. The strong disturbance happened in the region close to the plasma. (author)

  4. Electrodynamical Light Trapping Using Whispering-Gallery Resonances in Hyperbolic Cavities

    Directory of Open Access Journals (Sweden)

    Chihhui Wu

    2014-04-01

    Full Text Available We theoretically study spherical cavities composed of hyperbolic metamaterials with indefinite permittivity tensors. Such cavities are capable of electrodynamically confining fields with deep subwavelength cavity sizes. The supported resonant modes are analogous to the whispering-gallery modes found in dielectric microcavities with much larger physical sizes. Because of the nature of electrodynamical confinement, these hyperbolic metamaterial cavities exhibit quality factors higher than predicted in the electrostatic limit. In addition, confining electromagnetic fields into the small cavities results in an extremely high photonic local density of states.

  5. Mid infrared resonant cavity detectors and lasers with epitaxial lead-chalcogenides

    Science.gov (United States)

    Zogg, H.; Rahim, M.; Khiar, A.; Fill, M.; Felder, F.; Quack, N.

    2010-09-01

    Wavelength tunable emitters and detectors in the mid-IR wavelength region allow applications including thermal imaging and gas spectroscopy. One way to realize such tunable devices is by using a resonant cavity. By mechanically changing the cavity length with MEMS mirror techniques, the wavelengths may be tuned over a considerable range. Resonant cavity enhanced detectors (RCED) are sensitive at the cavity resonance only. They may be applied for low resolution spectroscopy, and, when arrays of such detectors are realized, as multicolour IR-FPA or "IR-AFPA", adaptive focal plane arrays. We report the first room temperature mid-IR VECSEL (vertical external cavity surface emitting laser) with a wavelength above 3 μm. The active region is just 850 nm PbSe, followed by a 2.5 pair Bragg mirror. Output power is > 10 mW at RT.

  6. Anomalous resonant reflection in a Fabry-Perot cavity filled with weakly scattering medium.

    Science.gov (United States)

    Hao, Ye; Gao, Wentao; Sun, Zhijun

    2018-03-01

    In this work, we fabricated a metallic Fabry-Perot cavity, filled with a weakly scattering medium of unsintered solgel silica, on a glass substrate. We found anomalous asymmetric resonance reflection spectra of this structure, besides the effects of scattering loss in cavity. The asymmetric reflection is shown to be dependent on the media on both sides of the cavity. It is thought that, as the weakly scattering medium locates between highly reflecting boundaries and the cavity length is far less than the mean free path of light in the medium, light scattering in the medium is enhanced at the resonance conditions and the scattering centers act as elementary sources emitting the scattered incoherent light to the outside of the cavity from both its ends. The asymmetric reflection then results from lossy total internal reflection of the scattered light at one of the boundaries, eventually leaking to the outside of the cavity with the higher index and contributing to the measured backside reflectance.

  7. High frequency generation in the corona: Resonant cavities

    Science.gov (United States)

    Santamaria, I. C.; Van Doorsselaere, T.

    2018-03-01

    Aims: Null points are prominent magnetic field singularities in which the magnetic field strength strongly decreases in very small spatial scales. Around null points, predicted to be ubiquitous in the solar chromosphere and corona, the wave behavior changes considerably. Null points are also responsible for driving very energetic phenomena, and for contributing to chromospheric and coronal heating. In previous works we demonstrated that slow magneto-acoustic shock waves were generated in the chromosphere propagate through the null point, thereby producing a train of secondary shocks escaping along the field lines. A particular combination of the shock wave speeds generates waves at a frequency of 80 MHz. The present work aims to investigate this high frequency region around a coronal null point to give a plausible explanation to its generation at that particular frequency. Methods: We carried out a set of two-dimensional numerical simulations of wave propagation in the neighborhood of a null point located in the corona. We varied both the amplitude of the driver and the atmospheric properties to investigate the sensitivity of the high frequency waves to these parameters. Results: We demonstrate that the wave frequency is sensitive to the atmospheric parameters in the corona, but it is independent of the strength of the driver. Thus, the null point behaves as a resonant cavity generating waves at specific frequencies that depend on the background equilibrium model. Moreover, we conclude that the high frequency wave train generated at the null point is not necessarily a result of the interaction between the null point and a shock wave. This wave train can be also developed by the interaction between the null point and fast acoustic-like magneto-acoustic waves, that is, this interaction within the linear regime.

  8. Cavity-enhanced surface-plasmon resonance sensing: Modeling and performance

    Czech Academy of Sciences Publication Activity Database

    Giorgini, A.; Avino, S.; Malara, P.; Zullo, R.; Gaglio, G.; Homola, Jiří; De Natale, P.

    2014-01-01

    Roč. 25, č. 1 (2014), 015205 ISSN 0957-0233 Institutional support: RVO:67985882 Keywords : optical resonators * optical sensors * cavity ring-down spectroscopy Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.433, year: 2014

  9. Ring-resonator-integrated tunable external cavity laser employing EAM and SOA.

    Science.gov (United States)

    Yoon, Ki-Hong; Kwon, O-Kyun; Kim, Ki Soo; Choi, Byung-Seok; Oh, Su Hwan; Kim, Hyun Su; Sim, Jae-Sik; Kim, Chul Soo

    2011-12-05

    We propose and demonstrate a tunable external cavity laser (ECL) composed of a polymer Bragg reflector (PBR) and integrated gain chip with gain, a ring resonator, an electro-absorption modulator (EAM), and a semiconductor optical amplifier (SOA). The cavity of the laser is composed of the PBR, gain, and ring resonator. The ring resonator reflects the predetermined wavelengths into the gain region and transmits the output signal into integrated devices such as the EAM and SOA. The output wavelength of the tunable laser is discretely tuned in steps of about 0.8 nm through the thermal-optic effect of the PBR and predetermined mode spacing of the ring resonator.

  10. Dynamic resonance of light in Fabry-Perot cavities

    International Nuclear Information System (INIS)

    Rakhmanov, M.; Savage, R.L.; Reitze, D.H.; Tanner, D.B.

    2002-01-01

    The dynamics of light in Fabry-Perot cavities with varying length and input laser frequency are analyzed. At high frequencies, the response to length variations is very different from the response to laser frequency variations. Implications for kilometer-scale Fabry-Perot cavities such as those utilized in gravitational-wave detectors are discussed

  11. Resonance frequency control of RF normal conducting cavity using gradient estimator of reflected power

    Science.gov (United States)

    Leewe, R.; Shahriari, Z.; Moallem, M.

    2017-10-01

    Control of the natural resonance frequency of an RF cavity is essential for accelerator structures due to their high cavity sensitivity to internal and external vibrations and the dependency of resonant frequency on temperature changes. Due to the relatively high radio frequencies involved (MHz to GHz), direct measurement of the resonant frequency for real-time control is not possible by using conventional microcontroller hardware. So far, all operational cavities are tuned using phase comparison techniques. The temperature dependent phase measurements render this technique labor and time intensive. To eliminate the phase measurement, reduce man hours and speed up cavity start up time, this paper presents a control theme that relies solely on the reflected power measurement. The control algorithm for the nonlinear system is developed through Lyapunov's method. The controller stabilizes the resonance frequency of the cavity using a nonlinear control algorithm in combination with a gradient estimation method. Experimental results of the proposed system on a test cavity show that the resonance frequency can be tuned to its optimum operating point while the start up time of a single cavity and the accompanied man hours are significantly decreased. A test result of the fully commissioned control system on one of TRIUMF's DTL tanks verifies its performance under real environmental conditions.

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

    OpenAIRE

    Zhang, Xiangao; Shao, Mingzhen; Zeng, Xiaoqi

    2016-01-01

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

  13. Bistable output from a coupled-resonator vertical-cavity laser diode

    International Nuclear Information System (INIS)

    Fischer, A. J.; Choquette, K. D.; Chow, W. W.; Allerman, A. A.; Geib, K.

    2000-01-01

    We report a monolithic coupled-resonator vertical-cavity laser with an ion-implanted top cavity and a selectively oxidized bottom cavity which exhibits bistable behavior in the light output versus injection current. Large bistability regions over current ranges as wide as 18 mA have been observed with on/off contrast ratios of greater than 20 dB. The position and width of the bistability region can be varied by changing the bias to the top cavity. Switching between on and off states can be accomplished with changes as small as 250 μW to the electrical power applied to the top cavity. The bistable behavior is the response of the nonlinear susceptibility in the top cavity to the changes in the bottom intracavity laser intensity as the bottom cavity reaches the thermal rollover point

  14. Bistable Output from a Coupled-Resonator Vertical-Cavity Laser Diode

    Energy Technology Data Exchange (ETDEWEB)

    FISCHER,ARTHUR J.; CHOQUETTE,KENT D.; CHOW,WENG W.; ALLERMAN,ANDREW A.; GEIB,KENT M.

    2000-07-20

    The authors report a monolithic coupled-resonator vertical-cavity laser with an ion-implanted top cavity and a selectively oxidized bottom cavity which exhibits bistable behavior in the light output versus injection current. Large bistability regions over current ranges as wide as 18 mA have been observed with on/off contrast ratios of greater than 20 dB. The position and width of the bistability region can be varied by changing the bias to the top cavity. Switching between on and off states can be accomplished with changes as small as 250 {micro}W to the electrical power applied to the top cavity. Theoretical analysis suggests that the bistable behavior is the response of the nonlinear susceptibility in the top cavity to the changes in the bottom intracavity laser intensity as the bottom cavity reaches the thermal rollover point.

  15. The use of microperforated plates to attenuate cavity resonances

    DEFF Research Database (Denmark)

    Fenech, Benjamin; Keith, Graeme; Jacobsen, Finn

    2006-01-01

    The use of microperforated plates to introduce damping in a closed cavity is examined. By placing a microperforated plate well inside the cavity instead of near a wall as traditionally done in room acoustics, high attenuation can be obtained for specific acoustic modes, compared with the lower at......'s functions. The results, which are validated experimentally, show that a microperforated plate can provide substantial attenuation of modes in a cavity. One possible application of these findings is the treatment of boiler tones in heat-exchanger cavities.......The use of microperforated plates to introduce damping in a closed cavity is examined. By placing a microperforated plate well inside the cavity instead of near a wall as traditionally done in room acoustics, high attenuation can be obtained for specific acoustic modes, compared with the lower...... attenuation that can be obtained in a broad frequency range with the conventional position of the plate. An analytical method for predicting the attenuation is presented. The method involves finding complex eigenvalues and eigenfunctions for the modified cavity and makes it possible to predict Green...

  16. Modeling resonant cavities for single-photon waveguide sources

    International Nuclear Information System (INIS)

    Evans, Philip G.; Bennink, Ryan S.; Grice, Warren P.

    2008-01-01

    Spectral correlations between photon pairs generated by spontaneous parametric down conversion (SPDC) in bulk non-linear optical crystals remain a hindrance to the implementation of efficient quantum communication architectures. It has been demonstrated that SPDC within a distributed micro-cavity can result in little or no correlation between photon pairs. We present results on modeling three different cavity configurations based on integrated Bragg gratings. Output from the SPDC process can be tailored by altering the periodicity and geometry of such nanostructures. We will discuss the merits of each cavity configuration from the standpoint of degenerate Type-II SPDC

  17. Challenges in resonant cavity biosensor design: collection efficiency and specificity

    Science.gov (United States)

    Armani, Andrea M.; Mehrabani, Simin; Sun, Victoria; McBirney, Samantha; Hawk, Rasheeda M.; Gungor, Eda; Lee, Michele

    2014-03-01

    Optical cavities have successfully demonstrated the ability to detect a wide range of analytes with exquisite sensitivity. However, optimizing other parameters of the system, such as collection efficiency and specificity, have remained elusive. This presentation will discuss some of the recent work in this area, including 3D COMSOL Multiphysics models including mass transfer and binding kinetics of different cavity geometries and covalent attachment methods for a wide range of biological and synthetic moieties. A few representative experimental demonstrations will also be presented.

  18. Polarization-independent magneto-electric Fano resonance in hybrid ring/disk hetero-cavity

    Science.gov (United States)

    Hao, Zhiqiang; Gao, Yune; Huang, Zhenxian; Liang, Xinyi

    2017-12-01

    In this work, we study the scattering properties of the hybrid ring/disk hetero-cavity and reveal the existence of polarization-independent magneto-electric Fano resonance. Such Fano resonance occurs through the destructive interference between the orthogonal electric and magnetic modes in hetero-cavity, where the Si ring provides additional magnetic response. Furthermore, dipole radiative enhancement is used to analysis magneto-electric response of the hetero-cavity and the spectral features of cavity can be used to quantitatively characterize by coupled oscillator model. Generation of magneto-electric Fano resonance in such nanostructures does not require any symmetry breaking and presents clear advantages over their asymmetric counterparts, as it is easier to fabricate and can be used in a wider range of technological applications.

  19. Study of Low Work Function Materials for Hot Cavity Resonance Ionization Laser Ion Sources

    CERN Document Server

    Catherall, R; Fedosseev, V; Marsh, B; Mattolat, C; Menna, Mariano; Österdahl, F; Raeder, S; Schwellnus, F; Stora, T; Wendt, K; CERN. Geneva. AB Department

    2008-01-01

    The selectivity of a hot cavity resonance ionization laser ion source (RILIS) is most often limited by contributions from competing surface ionization on the hot walls of the ionization cavity. In this article we present investigations on the properties of designated high-temperature, low-work function materials regarding their performance and suitability as cavity material for RILIS. Tungsten test cavities, impregnated with a mixture of barium oxide and strontium oxide (BaOSrO on W), or alternatively gadolinium hexaboride (GdB6) were studied in comparison to a standard tungsten RILIS cavity as being routinely used for hot cavity laser ionization at ISOLDE. Measurement campaigns took place at the off-line mass separators at ISOLDE / CERN, Geneva and RISIKO / University of Mainz.

  20. Study of low work function materials for hot cavity resonance ionization laser ion sources

    CERN Document Server

    Schwellnus, F; Crepieux, B; Fedosseev, V N; Marsh, B A; Mattolat, Ch; Menna, M; Österdahl, F K; Raeder, S; Stora, T; Wendta, K

    2009-01-01

    The selectivity of a hot cavity resonance ionization laser ion source (RILIS) is most often limited by contributions from competing surface ionization of the hot walls of the ionization cavity. In this article we present investigations on the properties of designated high temperature, low work function materials regarding their performance and suitability as cavity material for RILIS. Tungsten test cavities, impregnated with a mixture of barium oxide and strontium oxide (BaOSrO on W), or alternatively gadolinium hexaboride (GdB6) were studied in comparison to a standard tungsten RILIS cavity as being routinely used for hot cavity laser ionization at ISOLDE. Measurement campaigns took place at the off-line mass separators at ISOLDE/CERN, Geneva and RISIKO/University of Mainz.

  1. All-optical logic gates in plasmonic metal-insulator-metal nanowaveguide with slot cavity resonator

    Science.gov (United States)

    Dolatabady, Alireza; Granpayeh, Nosrat

    2017-04-01

    We demonstrate the compact all-optical logic XOR and OR gates in subwavelength plasmonic metal-insulator-metal waveguides with slot cavity resonators, especially for telecommunication wavelengths, with an extinction ratio of 25 dB, which can provide nanoscale logic integrated circuits. The gates behavior is based on suppression or enhancement of resonant modes in a slot cavity resonator induced by a change in position of input ports. The performance of the gates is discussed analytically and verified by the numerical method of finite-difference time-domain (FDTD).

  2. High-Q nested resonator in an actively stabilized optomechanical cavity

    Science.gov (United States)

    Buters, F. M.; Heeck, K.; Eerkens, H. J.; Weaver, M. J.; Luna, F.; de Man, S.; Bouwmeester, D.

    2017-03-01

    Experiments involving micro- and nanomechanical resonators need to be carefully designed to reduce mechanical environmental noise. A small scale on-chip approach is to add a resonator to the system as a mechanical low-pass filter. However, the inherent low frequency of the low-pass filter causes the system to be easily excited mechanically. We solve this problem by applying active feedback to the resonator, thereby minimizing the motion with respect to the front mirror of an optomechanical cavity. Not only does this method actively stabilize the cavity length but it also retains the on-chip vibration isolation.

  3. Air-coupled MUMPs capacitive micromachined ultrasonic transducers with resonant cavities.

    Science.gov (United States)

    Octavio Manzanares, Alberto; Montero de Espinosa, Francisco

    2012-04-01

    This work reports performance improvements of air-coupled capacitive micromachined ultrasonic transducers (CMUTs) using resonant cavities. In order to perform this work, we have designed and manufactured a CMUT employing multi-user microelectromechanical systems (MEMS) processes (MUMPs). The transducer was designed using Helmholtz resonator principles. This was characterised by the dimensions of the cavity and several acoustic ports, which had the form of holes in the CMUT plate. The MUMPs process has the advantage of being low cost which allows the manufacture of economic prototypes. In this paper we show the effects of the resonant cavities and acoustic ports in CMUTs using laser Doppler vibrometry and acoustical measurements. We also use Finite Element (FE) simulations in order to support experimental measurements. The results show that it is possible to enhance the output pressure and bandwidth in air by tuning the resonance frequency of the plate (f(p)) with that of the Helmholtz resonator (f(H)). The experimental measurements show the plate resonance along with an additional resonance in the output pressure spectrum. This appears due to the effect of the new resonant cavities in the transducer. FE simulations show an increase of 11 dB in the output pressure with respect to that of a theoretical vacuum-sealed cavity MUMPs CMUT by properly tuning the transducer. The bandwidth has been also analyzed by calculating the mechanical Q factor of the tuned CMUT. This has been estimated as 4.5 compared with 7.75 for the vacuum-sealed cavity MUMPs CMUT. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Effects of cavity resonances on sound transmission into a thin cylindrical shell. [noise reduction in aircraft fuselage

    Science.gov (United States)

    Koval, L. R.

    1978-01-01

    In the context of the transmission of airborne noise into an aircraft fuselage, a mathematical model is presented for the effects of internal cavity resonances on sound transmission into a thin cylindrical shell. The 'noise reduction' of the cylinder is defined and computed, with and without including the effects of internal cavity resonances. As would be expected, the noise reduction in the absence of cavity resonances follows the same qualitative pattern as does transmission loss. Numerical results show that cavity resonances lead to wide fluctuations and a general decrease of noise reduction, especially at cavity resonances. Modest internal absorption is shown to greatly reduce the effect of cavity resonances. The effects of external airflow, internal cabin pressurization, and different acoustical properties inside and outside the cylinder are also included and briefly examined.

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

    Indian Academy of Sciences (India)

    Harmonic resonance leads to period-1 bistability and hysteresis. Inside the period-2 sub-harmonic resonance region, the laser exhibits Feigenbaum sequence and generalized bistability. Keywords. Fibre lasers; chaos; modulation; nonlinear oscillators; optical bistability. PACS Nos 05.45.Ac; 42.55.Wd; 05.45.Tp; 42.55.Rz.

  6. Demonstration of acoustic resonances in a cylindrical cavity applying the photoacoustic technique

    Science.gov (United States)

    Barreiro, N. L.; Vallespi, A. S.; Zajarevich, N. M.; Peuriot, A. L.; Slezak, V. B.

    2017-09-01

    In this work we present some experiments which can be performed in college or on the first courses of university to acquire knowledge about resonant acoustical phenomena in closed cavities in a tangible way, through experiments based on the photoacoustic effect in gases. This phenomenon consists in the generation of acoustic waves after optical excitation of an absorbing gas and further local heating of the non-absorbing surrounding gas by energy exchange through collisions between molecules of both species. Simple experiments, performed with daily live elements, can be very useful for teachers and students to get in touch with the phenomenon of acoustic resonances with the addition of concepts about light-matter interaction. The setups consist of the resonant cavity, the illumination source and the signal detection-acquisition scheme. In this paper a closed glass test tube is used as the resonant cavity and is filled with a mixture of nitrogen dioxide and air. The illumination is performed by a pulsed power LED modulated at different resonant frequencies of the cavity. A microphone inside the tube is connected to an oscilloscope which displays the photoacoustic signal. The LED is moved along the tube showing how different resonant modes can be excited.

  7. Compact 400-Mhz Half-Wave Spoke Resonator Crab Cavity for the LHC Update

    International Nuclear Information System (INIS)

    Li, Zenghai

    2010-01-01

    Crab cavities are proposed for the LHC upgrade to improve the luminosity. There are two possible crab cavity installations for the LHC upgrade: the global scheme at Interaction Region (IR) 4 where the beam-beam separation is about 420-mm, and the local scheme at the IR5 where the beam-beam separation is only 194-mm. One of the design requirements as the result of a recent LHC-Crab cavity workshop is to develop a 400-MHz cavity design that can be utilized for either the global or local schemes at IR4 or IR5. Such a design would offer more flexibility for the final upgrade installation, as the final crabbing scheme is yet to be determined, and save R and D cost. The cavity size of such a design, however, is limited by the beam-beam separation at IR5 which can only accommodate a cavity with a horizontal size of about 145-mm, which is a design challenge for a 400-MHz cavity. To meet the new design requirements, we have developed a compact 400-MHz half-wave spoke resonator (HWSR) crab cavity that can fit into the tight spaces available at either IR4 or IR5. In this paper, we present the optimization of the HWSR cavity shape and the design of HOM, LOM, and SOM couplers for wakefield damping.

  8. Cavity optomechanics nano- and micromechanical resonators interacting with light

    CERN Document Server

    Kippenberg, Tobias; Marquardt, Florian

    2014-01-01

    During the last few years cavity-optomechanics has emerged as a new field of research. This highly interdisciplinary field studies the interaction between micro- and nanomechanical systems and light. Possible applications range from novel high-bandwidth mechanical sensing devices through the generation of squeezed optical or mechanical states to even tests of quantum theory itself. This is one of the first books in this relatively young field. it is aimed at scientists, engineers, and students who want to obtain a concise introduction to the state of the art in the field of cavity optomechanics. It is valuable to researchers in nanoscience, quantum optics, quantum information, gravitational wave detection and other cutting edge fields. Possible applications include biological sensing, frequency comb applications, silicon photonics etc. The technical content will be accessible to those who have familiarity with basic undergraduate physics.

  9. Hybrid III-V/SOI resonant cavity enhanced photodetector

    DEFF Research Database (Denmark)

    Learkthanakhachon, Supannee; Taghizadeh, Alireza; Park, Gyeong Cheol

    2016-01-01

    as part of the HG reflector, enabling a very compact vertical cavity. Numerical investigations show that a quantum efficiency close to 100 % and a detection linewidth of about 1 nm can be achieved, which are desirable for wavelength division multiplexing applications. Based on these results, a hybrid RCE......-PD operation. In addition, a capability of feasibly selecting the detection wavelength during fabrication as well as a possibility of realizing silicon-integrated bidirectional transceivers are discussed....

  10. Polariton Resonances for Ultrastrong Coupling Cavity Optomechanics in GaAs/AlAs Multiple Quantum Wells.

    Science.gov (United States)

    Jusserand, B; Poddubny, A N; Poshakinskiy, A V; Fainstein, A; Lemaitre, A

    2015-12-31

    Polariton-mediated light-sound interaction is investigated through resonant Brillouin scattering experiments in GaAs/AlAs multiple-quantum wells. Photoelastic coupling enhancement at exciton-polariton resonance reaches 10(5) at 30 K as compared to a typical bulk solid room temperature transparency value. When applied to GaAs based cavity optomechanical nanodevices, this result opens the path to huge displacement sensitivities and to ultrastrong coupling regimes in cavity optomechanics with couplings g(0) in the range of 100 GHz.

  11. High quality ultrafast transmission electron microscopy using resonant microwave cavities.

    Science.gov (United States)

    Verhoeven, W; van Rens, J F M; Kieft, E R; Mutsaers, P H A; Luiten, O J

    2018-03-10

    Ultrashort, low-emittance electron pulses can be created at a high repetition rate by using a TM 110 deflection cavity to sweep a continuous beam across an aperture. These pulses can be used for time-resolved electron microscopy with atomic spatial and temporal resolution at relatively large average currents. In order to demonstrate this, a cavity has been inserted in a transmission electron microscope, and picosecond pulses have been created. No significant increase of either emittance or energy spread has been measured for these pulses. At a peak current of 814 ± 2 pA, the root-mean-square transverse normalized emittance of the electron pulses is ɛ n,x =(2.7±0.1)·10 -12  m rad in the direction parallel to the streak of the cavity, and ɛ n,y =(2.5±0.1)·10 -12  m rad in the perpendicular direction for pulses with a pulse length of 1.1-1.3 ps. Under the same conditions, the emittance of the continuous beam is ɛ n,x =ɛ n,y =(2.5±0.1)·10 -12  m rad. Furthermore, for both the pulsed and the continuous beam a full width at half maximum energy spread of 0.95 ± 0.05 eV has been measured. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Bright cavity solitons in metamaterials with internal resonances

    Czech Academy of Sciences Publication Activity Database

    Yulin, A.V.; Kuzmiak, Vladimír; Eyderman, Sergey

    2015-01-01

    Roč. 91, č. 6 (2015), s. 063820 ISSN 1050-2947 R&D Projects: GA MŠk(CZ) LD14028 Grant - others:COST(XE) MP1204 Institutional support: RVO:67985882 Keywords : Plasmons * Dissipative soliton s * Resonators Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.808, year: 2014

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

    Indian Academy of Sciences (India)

    - verse mode and multiaxial mode) with an intracavity LiNbO3 electro-optic modulator. (EOM) display the characteristic features of a nonlinear oscillator (e.g., harmonic and period-2 sub-harmonic resonances) when the EOM driver voltage is ...

  14. Surface plasmon resonance optical cavity enhanced refractive index sensing

    Czech Academy of Sciences Publication Activity Database

    Giorgini, A.; Avino, S.; Malara, P.; Gagliardi, G.; Casalino, M.; Coppola, G.; Iodice, M.; Adam, Pavel; Chadt, Karel; Homola, Jiří; De Natale, P.

    2013-01-01

    Roč. 38, č. 11 (2013), s. 1951-1953 ISSN 0146-9592 R&D Projects: GA ČR GBP205/12/G118 Institutional support: RVO:67985882 Keywords : Resonators * Surface plasmons * Optical sensing and sensors Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.179, year: 2013

  15. Imaging characteristics of a Stafne bone cavity--panoramic radiography, computed tomography and magnetic resonance imaging.

    Science.gov (United States)

    Probst, Florian Andreas; Probst, Monika; Maistreli, Ira-Zacharoula; Otto, Sven; Troeltzsch, Matthias

    2014-09-01

    A rare case of Stafne bone cavity (SBC) with salivary gland herniation confirmed by magnetic resonance imaging (MRI) is described. It was diagnosed in a 72-year-old male patient. Surgical intervention was avoided. The report highlights imaging findings of panoramic radiography, computed tomography, and especially magnetic resonance tomography. It is demonstrated that employment of MRI for further evaluation of suspicion of SBC on panoramic radiographs can be a helpful diagnostic tool.

  16. Efficient 525 nm laser generation in single or double resonant cavity

    Science.gov (United States)

    Liu, Shilong; Han, Zhenhai; Liu, Shikai; Li, Yinhai; Zhou, Zhiyuan; Shi, Baosen

    2018-03-01

    This paper reports the results of a study into highly efficient sum frequency generation from 792 and 1556 nm wavelength light to 525 nm wavelength light using either a single or double resonant ring cavity based on a periodically poled potassium titanyl phosphate crystal (PPKTP). By optimizing the cavity's parameters, the maximum power achieved for the resultant 525 nm laser was 263 and 373 mW for the single and double resonant cavity, respectively. The corresponding quantum conversion efficiencies were 8 and 77% for converting 1556 nm photons to 525 nm photons with the single and double resonant cavity, respectively. The measured intra-cavity single pass conversion efficiency for both configurations was about 5%. The performances of the sum frequency generation in these two configurations was studied and compared in detail. This work will provide guidelines for optimizing the generation of sum frequency generated laser light for a variety of configurations. The high conversion efficiency achieved in this work will help pave the way for frequency up-conversion of non-classical quantum states, such as the squeezed vacuum and single photon states. The proposed green laser source will be used in our future experiments, which includes a plan to generate two-color entangled photon pairs and achieve the frequency down-conversion of single photons carrying orbital angular momentum.

  17. IV-VI mid-IR tunable lasers and detectors with external resonant cavities

    Science.gov (United States)

    Zogg, H.; Rahim, M.; Khiar, A.; Fill, M.; Felder, F.; Quack, N.; Blunier, S.; Dual, J.

    2009-08-01

    Wavelength tunable emitters and detectors in the mid-IR wavelength region allow applications including thermal imaging and spectroscopy. Such devices may be realized using a resonant cavity. By mechanically changing the cavity length with MEMS mirror techniques, the wavelengths may be tuned over a considerable range. Vertical external cavity surface emitting lasers (VECSEL) may be applied for gas spectroscopy. Resonant cavity enhanced detectors (RCED) are sensitive at the cavity resonance only. They may be applied for low resolution spectroscopy, and, when arrays of such detectors are realized, as multicolor IR-FPA or IR-AFPA (IR-adaptive focal plane arrays). We review mid-infrared RCEDs and VECSELs using narrow gap IV-VI (lead chalcogenide) materials like PbTe and PbSe as the active medium. IV-VIs are fault tolerant and allow easy wavelength tuning. The VECSELs operate up to above room temperature and emit in the 4 - 5 μm range with a PbSe active layer. RCEDs with PbTe absorbing layers above 200 K operating temperature have higher sensitivities than the theoretical limit for a similar broad-band detector coupled with a passive tunable band-filter.

  18. Development of 400- to 450-MHz RFQ resonator-cavity mechanical designs

    International Nuclear Information System (INIS)

    Hansborough, L.D.

    1982-01-01

    In the development of the radio-frequency quadrupole (RFQ) linac, the resonator cavity's mechanical design may be a challenge similar in magnitude to that of the development of the accelerator structure itself. Experience with the all-copper 425-MHz RFQ proof-of-principle linac has demonstrated that the resonator cavity must be structurally stiff and easily tunable. This experience has led to development of copper-plated steel structures having vanes that may be moved within a cylinder for tuning. Design of a flexible vane-to-cylinder radio-frequency (rf) joint, the vane, and the cylinder has many constraints dictated by the small-diameter cavities in the 400-MHz-frequency region. Two types of flexible, mechanical vane-to-cylinder rf joints are being developed at Los Alamos: the C-seal and the rf clamp-joint

  19. The imaging anatomical consideration of the resonance of the cranial cavity

    International Nuclear Information System (INIS)

    Lee, Dong Myoung

    2000-01-01

    Because vocal technique is the basis of singing a song beautifully, so this study was undertaken to use the scientific and correct technique in order to get much better musical expressions. Shimadzu X-ray remote control TV system was used for checking the supporting state of diaphragmatic respiration after 5, 10, 15, 20, 25 and 30 sec during phonation in the state of full inhalation between professional singer and non-professional singer. Shimadzu Magnet nex-α(SMT-50CX/H) was used for examining the scattering state from the resonance of nasal caity to that of cranial cavity on the basis of diaphragmatic respiration. The results obtained were summerized as follows: 1. The resonance of cranial cavity must be scattered by the energy of diaphragmatic respiration after gathering the foci of the fundamental 5 vowels. 2. While raising the epiglottis, the resonance of nasal cavity must be clearly in order to maintain the resonance of cranial cavity beautifully. 3. We can get musical expressions by maintaining the elasticity of diaphragmatic respiration.=20

  20. Cavitation tunnel analysis of radiated sound from the resonance of a propeller tip vortex cavity

    NARCIS (Netherlands)

    Pennings, P.C.; Westerweel, J.; Van Terwisga, T.J.C.

    2016-01-01

    The goal of this study is to test the hypothesis that the resonance of a tip vortex cavity is responsible for high-amplitude broadband pressure-fluctuations, typically between 40 and 70 Hz,Hz, for a full scale propeller. This is achieved with a model propeller in a cavitation tunnel. Simultaneous

  1. Cavities

    Science.gov (United States)

    ... mother's bacteria from being passed to the child. Treatment of Cavities Fluoride Fillings Root canal or tooth extraction If ... to help the world be well. From developing new therapies that treat and prevent disease to helping people ...

  2. Resonant cavity light-emitting diodes based on dielectric passive cavity structures

    Science.gov (United States)

    Ledentsov, N.; Shchukin, V. A.; Kropp, J.-R.; Zschiedrich, L.; Schmidt, F.; Ledentsov, N. N.

    2017-02-01

    A novel design for high brightness planar technology light-emitting diodes (LEDs) and LED on-wafer arrays on absorbing substrates is proposed. The design integrates features of passive dielectric cavity deposited on top of an oxide- semiconductor distributed Bragg reflector (DBR), the p-n junction with a light emitting region is introduced into the top semiconductor λ/4 DBR period. A multilayer dielectric structure containing a cavity layer and dielectric DBRs is further processed by etching into a micrometer-scale pattern. An oxide-confined aperture is further amended for current and light confinement. We study the impact of the placement of the active region into the maximum or minimum of the optical field intensity and study an impact of the active region positioning on light extraction efficiency. We also study an etching profile composed of symmetric rings in the etched passive cavity over the light emitting area. The bottom semiconductor is an AlGaAs-AlAs multilayer DBR selectively oxidized with the conversion of the AlAs layers into AlOx to increase the stopband width preventing the light from entering the semiconductor substrate. The approach allows to achieve very high light extraction efficiency in a narrow vertical angle keeping the reasonable thermal and current conductivity properties. As an example, a micro-LED structure has been modeled with AlGaAs-AlAs or AlGaAs-AlOx DBRs and an active region based on InGaAlP quantum well(s) emitting in the orange spectral range at 610 nm. A passive dielectric SiO2 cavity is confined by dielectric Ta2O5/SiO2 and AlGaAs-AlOx DBRs. Cylindrically-symmetric structures with multiple ring patterns are modeled. It is demonstrated that the extraction coefficient of light to the air can be increased from 1.3% up to above 90% in a narrow vertical angle (full width at half maximum (FWHM) below 20°). For very small oxide-confined apertures 100nm the narrowing of the FWHM for light extraction can be reduced down to 5

  3. Waveguide Cavity Resonator as a Source of Optical Squeezing

    Science.gov (United States)

    Stefszky, M.; Ricken, R.; Eigner, C.; Quiring, V.; Herrmann, H.; Silberhorn, C.

    2017-04-01

    We present the generation of continuous-wave optical squeezing from a titanium-in-diffused lithium niobate waveguide resonator. We directly measure 2.9 ±0.1 dB of single-mode squeezing, which equates to a produced level of 4.9 ±0.1 dB after accounting for detection losses. This device showcases the current capabilities of this waveguide architecture and precipitates more complicated integrated continuous-wave quantum devices in the continuous-variable regime.

  4. Ultra-wide-band accumulation of coherent undulator synchrotron radiation in a resonating cavity

    Directory of Open Access Journals (Sweden)

    Y. H. Seo

    2011-06-01

    Full Text Available Cavity accumulation of coherent undulator synchrotron radiation emitted by a train of periodic electron bunches is investigated. Phase-matching conditions for accumulation of radiation emitted by successive bunches are analyzed and numerically confirmed. While the coherent emission of a single bunch is optimal at grazing resonance, the accumulated radiation targeted at the upper resonant frequency of the waveguide mode is found to have much broader bandwidth and higher efficiency as the resonance steps away from the grazing condition. Numerical results confirm that stimulated superradiance is responsible for the accumulated radiation.

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

    Science.gov (United States)

    Zhang, Xiangao; Shao, Mingzhen; Zeng, Xiaoqi

    2016-10-18

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

  6. Fano resonances in photonic crystal nanobeams side-coupled with nanobeam cavities

    Science.gov (United States)

    Meng, Zi-Ming; Liang, Anhui; Li, Zhi-Yuan

    2017-05-01

    Fano resonances usually arise when a narrow resonance or discrete state and a broad resonance or continuum state are coupled. In this paper, we theoretically and numerically study asymmetric Fano line shape realized in a photonic crystal nanobeam (PCN) side-coupled with a photonic crystal nanobeam cavity (PCNC). Asymmetric transmission profiles with a transmission peak and a transmission valley are obtained for a low index concentrated cavity mode. The transmission valley, associated with the destructive interference, of our PCN-PCNC structures is deeper than that of a waveguide or Fabry-Perot resonator side-coupled with a PCNC structure. Through changing the position of the photonic band gap (PBG) of the PCN, we can utilize the high or low frequency band edge modes and the Fano transmission profiles can be further controlled. The transmission spectra of our PCN-PCNC structures can be well fitted by the Fano resonance formula and agree qualitatively with the prediction made by the temporal coupled mode theory. By using the band edge modes of the PCN as the continuum state instead of a usual broad resonance, we have demonstrated a new way to generate a prominent Fano resonance. Our PCN-PCNC structures are compact and feasible to achieve large-scale high-performance integrated photonic devices, such as optical modulators or switches.

  7. X-ray Resonance in Crystal Cavities--Realization of Fabry-Perot Resonator for Hard X-rays

    OpenAIRE

    Chang, S. -L.; Stetsko, Yu. P.; Tang, M. -T.; Lee, Y. -R.; Sun, W. -H.; Yabashi, M.; Ishikawa, T.

    2004-01-01

    X-ray back diffraction from monolithic two silicon crystal plates of 25--150 um thick and a 40--150 um gap using synchrotron radiation of energy resolution deltaE=0.36 meV at 14.4388 keV shows clearly resonance fringes inside the energy gap and the total-reflection range for the (12 4 0) reflection. This cavity resonance results from the coherent interaction between the X-ray wavefields generated by the two plates with a gap smaller than the X-ray coherence length. This finding opens up new o...

  8. Differential ultrafast all-optical switching of the resonances of a micropillar cavity

    Energy Technology Data Exchange (ETDEWEB)

    Thyrrestrup, Henri, E-mail: h.t.nielsen@utwente.nl; Yüce, Emre; Ctistis, Georgios; Vos, Willem L. [Complex Photonic Systems (COPS), MESA Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands); Claudon, Julien; Gérard, Jean-Michel, E-mail: jean-michel.gerard@cea.fr [University Grenoble Alpes, INAC-SP2M, Nanophysics and Semiconductors Lab, F-38000 Grenoble (France); CEA, INAC-SP2M, Nanophysics and Semiconductors Lab, F-38000 Grenoble (France)

    2014-09-15

    We perform frequency- and time-resolved all-optical switching of a GaAs-AlAs micropillar cavity using an ultrafast pump-probe setup. The switching is achieved by two-photon excitation of free carriers. We track the cavity resonances in time with a high frequency resolution. The pillar modes exhibit simultaneous frequency shifts, albeit with markedly different maximum switching amplitudes and relaxation dynamics. These differences stem from the non-uniformity of the free carrier density in the micropillar, and are well understood by taking into account the spatial distribution of injected free carriers, their spatial diffusion and surface recombination at micropillar sidewalls.

  9. Transmission and refractive index sensing based on Fano resonance in MIM waveguide-coupled trapezoid cavity

    Directory of Open Access Journals (Sweden)

    Jinli Zhou

    2017-01-01

    Full Text Available A metal–insulator–metal (MIM waveguide-coupled trapezoid cavity is presented, and the transmission properties are investigated by finite-element method. Results show that an asymmetric Fano profile emerged in the transmission spectrum, which was caused by the asymmetrical break of the MIM waveguide-coupled trapezoid cavity system. A refractive index sensitivity, Q-factor and FOM of approximately 750nm/RIU, 68.3 and 65.2 were measured based on the Fano resonance. The effect of the structural parameters on the transmission properties is also investigated. The results provide a new possibility for designing high-performance plasmonic devices.

  10. Cavities

    Science.gov (United States)

    ... Additional Content Medical News Cavities ˈkav-ət-ē (Dental Caries) By James T. Ubertalli, DMD, Private Practice, Hingham, ... access to dental care, and better treatment for tooth decay and periodontal disease. When teeth are lost, chewing is greatly hindered, and speaking ...

  11. A non-resonant RF cavity loaded with amorphous alloy for proton cancer therapy

    CERN Document Server

    Makita, Y; Nayayama, T; Tsuchidate, H; Tsukishima, C; Yoshida, K

    1999-01-01

    A non-resonant RF cavity loaded with amorphous alloy cores has been designed and tested. The cavity has a re-entrant structure loaded with 8 amorphous alloy toroidal core and its characteristic impedance is designed as 450 Omega . The RF power is fed by 1 kW solid state amplifier using a step-up transformer with 1:9 impedance ratio. In the high power test, an accelerating gap voltage of more than 900 V was measured with input power of 1 kW in the frequency range of 1 to 10 MHz. The voltage standing wave ratio (VSWR) was less than 2.0. The results prove that the cavity may be used successfully within a compact proton synchrotron for a cancer therapy facility. (3 refs).

  12. High-Precision Resonant Cavity Beam Position, Emittance and Third-Moment Monitors

    CERN Document Server

    Barov, Nikolai; Miller, Roger H; Nantista, Christopher D; Weidemann, A W

    2005-01-01

    Linear colliders and FEL facilities need fast, nondestructive beam position and profile monitors to facilitate machine tune-up, and for use with feedback control. FAR-TECH, Inc. is developing a resonant cavity diagnostic to simultaneously measure the dipole, quadrupole and sextupole moments of the beam distribution. Measurements of dipole and quadrupole moments at multiple locations yield information about beam orbit and emittance. The sextupole moment can reveal information about beam asymmetry which is useful in diagnosing beam tail deflections caused by short range dipole wakefields. In addition to the resonance enhancement of a single-cell cavity, use of a multi-cell standign-wave structure further enhances signal strength and improves the resolution of the device. An estimated rms beam size resolution is sub micro-meters and beam position is sub nano-meter.

  13. Resonant cavity enhanced light harvesting in flexible thin-film organic solar cells

    KAUST Repository

    Sergeant, Nicholas P.

    2013-04-24

    Dielectric/metal/dielectric (DMD) electrodes have the potential to significantly increase the absorption efficiency and photocurrent in flexible organic solar cells. We demonstrate that this enhancement is attributed to a broadband cavity resonance. Silver-based semitransparent DMD electrodes with sheet resistances below 10 ohm/sq. are fabricated on flexible polyethylene terephthalate (PET) substrates in a high-throughput roll-to-roll sputtering tool. We carefully study the effect of the semitransparent DMD electrode (here composed of ZnxSnyOz/Ag/InxSn yOz) on the optical device performance of a copper phthalocyanine (CuPc)/fullerene (C60) bilayer cell and illustrate that a resonant cavity enhanced light trapping effect dominates the optical behavior of the device. © 2013 Optical Society of America.

  14. Bistable laser device with multiple coupled active vertical-cavity resonators

    Science.gov (United States)

    Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

    2003-08-19

    A new class of bistable coupled-resonator vertical-cavity semiconductor laser devices has been developed. These bistable laser devices can be switched, either electrically or optically, between lasing and non-lasing states. A switching signal with a power of a fraction of a milliwatt can change the laser output of such a device by a factor of a hundred, thereby enabling a range of optical switching and data encoding applications.

  15. Nanoscale photonic crystal sensor arrays on monolithic substrates using side-coupled resonant cavity arrays.

    Science.gov (United States)

    Yang, Daquan; Tian, Huiping; Ji, Yuefeng

    2011-10-10

    We present nanoscale photonic crystal sensor arrays (NPhCSAs) on monolithic substrates. The NPhCSAs can be used as an opto-fluidic architecture for performing highly parallel, label-free detection of biochemical interactions in aqueous environments. The architecture consists of arrays of lattice-shifted resonant cavities side-coupled to a single PhC waveguide. Each resonant cavity has slightly different cavity spacing and is shown to independently shift its resonant peak (a single and narrow drop) in response to the changes in refractive index. The extinction ratio of well-defined single drop exceeds 20 dB. With three-dimensional finite-difference time-domain (3D-FDTD) technique, we demonstrate that the refractive index sensitivity of 115.60 nm/RIU (refractive index unit) is achieved and a refractive index detection limit is approximately of 8.65×10-5 for this device. In addition, the sensitivity can be adjusted from 84.39 nm/RIU to 161.25 nm/RIU by changing the number of functionalized holes.

  16. Pathologies of the uterine endometrial cavity: usual and unusual manifestations and pitfalls on magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Mayumi; Matsuzaki, Kenji; Yoshida, Shusaku; Nishitani, Hiromu [University of Tokushima, Department of Radiology, Tokushima (Japan); Uehara, Hisanori [University of Tokushima, Department of Molecular and Environmental Pathology, Tokushima (Japan); Shimazu, Hideki [Oe Kyoudo Hospital, Department of Radiology (Japan)

    2005-11-01

    The endometrial cavity may demonstrate various imaging manifestations such as normal, reactive, inflammatory, and benign and malignant neoplasms. We evaluated usual and unusual magnetic resonance imaging (MRI) findings of the uterine endometrial cavity, and described the diagnostic clues to differential diagnoses. Surgically proven pathologies of the uterine endometrial cavity were evaluated retrospectively with pathologic correlation. The pathologies included benign endometrial neoplasms such as endometrial hyperplasia and polyp, malignant endometrial neoplasms such as endometrial carcinoma and carcinosarcoma, endometrial-myometrial neoplasm such as endometrial stromal sarcoma, pregnancy-related lesions in the endometrial cavity such as gestational trophoblastic diseases (hydatidiform mole, invasive mole and choriocarcinoma) and placental polyp, myometrial lesions simulating endometrial lesions such as submucosal leiomyoma and some adenomyosis, endometrial neoplasms simulating myometrial lesions such as adenomyomatous polyp and endometrial lesions arising in the hemicavity of a septate/bicornate uterus, and fluid collections in the uterine cavity (hydro/hemato/pyometra). It is important to recognize various imaging findings in these diseases, in order to make a correct preoperative diagnosis. (orig.)

  17. Hybrid nanoparticle-nanoline plasmonic cavities as SERS substrates with gap-controlled enhancements and resonances

    Science.gov (United States)

    Sharma, Yashna; Dhawan, Anuj

    2014-02-01

    We present hybrid nanoline-nanoparticle plasmonic substrates which allow easily achievable sub-5 nm gaps and a possibility of large-area fabrication. These substrates—based on plasmonic nanocavities formed by arrays of plasmonic nanoparticle (NP) dimers lying inside periodic metal nanolines (NLs)—can be used as tunable surface enhanced Raman scattering (SERS) substrates due to the tunability of cavity modes in the gap regions. Theoretical studies were conducted, using finite difference time domain (FDTD) modeling, to understand the plasmon resonance tunability as a function of gaps in these hybrid plasmonic substrates. The gaps forming the nanocavities include those between nanolines and nanoparticles (NL-NP) and between two nanoparticles (NP-NP). Our analysis reveals that these gaps play a combined role in tuning the resonance wavelength and the magnitude of electromagnetic field enhancement. Moreover, distinct structure-dependent plasmon resonance peaks are present in addition to material-dependent resonance peaks characteristic to the metal involved. Replacing the spherical particle arrays inside the nanolines with nanorod arrays revealed the possibility of tuning the plasmon resonance in the near-infrared regime. This indicates that there is a possibility of tuning the plasmon resonance wavelength to any region of the visible or near-infrared spectrum by changing the size or shape of the particles assembled inside these plasmonic nanolines.

  18. A study of nasal cavity volume in patients with cleft lip and palate by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Nakano, Kenichi

    1996-01-01

    Nasal cavity volume was studied in 11 patients with cleft lip and palate by magnetic resonance imaging. The areas of horizontal sections of the nasal cavity on the cleft and non-cleft sides were measured with the help of a personal computer and image analyzing software. Nasal cavity volume was determined by integrated volume calculation. The volume of each side was measured before and after cleft lip repair. Before cleft lip repair nasal cavity volume on the non-cleft side was larger than on the cleft side. However there was no significant difference in the volume of the cleft and non-cleft sides after cleft lip repair. (author)

  19. A study of nasal cavity volume in patients with cleft lip and palate by magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Kenichi [Showa Univ., Tokyo (Japan). School of Medicine

    1996-02-01

    Nasal cavity volume was studied in 11 patients with cleft lip and palate by magnetic resonance imaging. The areas of horizontal sections of the nasal cavity on the cleft and non-cleft sides were measured with the help of a personal computer and image analyzing software. Nasal cavity volume was determined by integrated volume calculation. The volume of each side was measured before and after cleft lip repair. Before cleft lip repair nasal cavity volume on the non-cleft side was larger than on the cleft side. However there was no significant difference in the volume of the cleft and non-cleft sides after cleft lip repair. (author)

  20. Spectrum reshaping of micro-ring resonator via an integrated Fabry-Perot cavity

    Science.gov (United States)

    Wu, Jiayang; Moein, Tania; Xu, Xingyuan; Ren, Guanghui; Mitchell, Arnan; Moss, David J.

    2018-01-01

    We investigate the enhancement in the filtering quality (Q) factor of an integrated micro-ring resonator (MRR) by embedding it in an integrated Fabry-Perot (FP) cavity formed by cascaded Sagnac loop reflectors (SLRs). By using coherent interference within the FP cavity to reshape the transmission spectrum of the MRR, both the Q factor and the extinction ratio (ER) can be greatly improved. The device is theoretically analyzed, and practically fabricated on a silicon-on-insulator (SOI) platform. Experimental results show that up to 11-times improvement in Q factor and an 8-dB increase in ER can be achieved via our proposed method. The impact of varying structural parameters on the device performance is also investigated and verified.

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

    KAUST Repository

    Amin, Muhammad Ruhul

    2012-08-10

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

  2. Design of Transparent Anodes for Resonant Cavity Enhanced Light Harvesting in Organic Solar Cells

    KAUST Repository

    Sergeant, Nicholas P.

    2012-01-03

    The use of an ITO-free MoO 3/Ag/MoO 3 anode to control the photon harvesting in PCDTBT:PC 70BM solar cells is proposed. At first sight, the fact that these anodes possess reduced far-field transmission compared to ITO may seem to be a disadvantage. But, despite this, we show that by carefully tuning the resonant optical cavity we can enhance the external quantum efficiency close to the band edge of PCDTBT, resulting in high photocurrent and power conversion efficiency on par with ITO. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Tunable Resonant-Cavity-Enhanced Photodetector with Double High-Index-Contrast Grating Mirrors

    DEFF Research Database (Denmark)

    Learkthanakhachon, Supannee; Yvind, Kresten; Chung, Il-Sug

    2013-01-01

    In this paper, we propose a broadband-tunable resonant-cavity-enhanced photodetector (RCE-PD) structure with double high-index-contrast grating (HCG) mirrors and numerically investigate its characteristics. The detector is designed to operate at 1550-nm wavelength. The detector structure consists...... of a top InP HCG mirror, a p-i-n photodiode embedding multiple quantum wells, and a Si HCG mirror formed in the Si layer of a silicon-on-insulator wafer. The detection wavelength can be changed by moving the top InP HCG mirror suspended in the air. High reflectivity and small penetration length of HCGs...

  4. Device Fabrication of 60 μm Resonant Cavity Light-Emitting Diode

    Directory of Open Access Journals (Sweden)

    J. J. C. Reyes

    2004-12-01

    Full Text Available An array of 60-mm-diameter resonant cavity light-emitting diodes suited for coupling with fiber opticwere fabricated using standard device fabrication technique. I-V characterization was used to determinethe viability of the device fabricating process. Under forward bias, the turn-on voltage of the devices is1.95–2.45 V with a series resistance of 17–14 kW. Under reverse bias, the devices showed a breakdownvoltage of 35 V.

  5. A pulsated weak-resonant-cavity laser diode with transient wavelength scanning and tracking for injection-locked RZ transmission.

    Science.gov (United States)

    Lin, Gong-Ru; Chi, Yu-Chieh; Liao, Yu-Sheng; Kuo, Hao-Chung; Liao, Zhi-Wang; Wang, Hai-Lin; Lin, Gong-Cheng

    2012-06-18

    By spectrally slicing a single longitudinal-mode from a master weak-resonant-cavity Fabry-Perot laser diode with transient wavelength scanning and tracking functions, the broadened self-injection-locking of a slave weak-resonant-cavity Fabry-Perot laser diode is demonstrated to achieve bi-directional transmission in a 200-GHz array-waveguide-grating channelized dense-wavelength-division-multiplexing passive optical network system. Both the down- and up-stream slave weak-resonant-cavity Fabry-Perot laser diodes are non-return-to-zero modulated below threshold and coherently injection-locked to deliver the pulsed carrier for 25-km bi-directional 2.5 Gbits/s return-to-zero transmission. The master weak-resonant-cavity Fabry-Perot laser diode is gain-switched at near threshold condition and delivers an optical coherent pulse-train with its mode linewidth broadened from 0.2 to 0.8 nm by transient wavelength scanning, which facilitates the broadband injection-locking of the slave weak-resonant-cavity Fabry-Perot laser diodes with a threshold current reducing by 10 mA. Such a transient wavelength scanning induced spectral broadening greatly releases the limitation on wavelength injection-locking range required for the slave weak-resonant-cavity Fabry-Perot laser diode. The theoretical modeling and numerical simulation on the wavelength scanning and tracking effects of the master and slave weak-resonant-cavity Fabry-Perot laser diodes are performed. The receiving power sensitivity for back-to-back transmission at bit-error-rate transmission is less than 2 dB for all 16 channels.

  6. Resonant cavity enhanced photodetectors for high-speed and polarization-sensing applications

    Science.gov (United States)

    Onat, Bora M.

    1998-08-01

    The performance of today's optical components utilized in communication systems have reached the conventional limitations and require innovations in device structures for further improvements. We employ the unique properties of the resonant cavity enhanced (RCE) photodetection scheme to increase the functionality and performance of semiconductor photodiodes. The operation principle of RCE photodetection is based on a new family of opto-electronic devices whose performance is enhanced by placing the active device structure inside a Fabry-Perot resonant microcavity. The RCE devices benefit from the wavelength sensitivity and the large increase of the resonant optical field introduced by the cavity. The increased optical field allows photodetectors to be made thinner and therefore faster, while simultaneously increasing the quantum efficiency at the resonant wavelengths. The research effort implemented all aspects of the device development including simulation, design, fabrication and characterization of photodiodes for high-speed and polarization-sensing applications. We studied the performance of RCE photodiodes through simulations and experimentally demonstrated their high- speed operation. Our simulation results predict a three- fold increase in the bandwidth-efficiency product (BWE) for RCE photodiodes. We designed, fabricated and characterized RCE Schottky photodiodes where the semi- transparent metal contact also functions as the top reflector. The RCE Schottky photodiode design for 900 nm wavelength operation exhibited a 10 ps temporal pulse width, corresponding to an estimated device bandwidth of 100 GHz. A peak quantum efficiency of 20% was measured and the theoretical expected value is 70%. A similar RCE Schottky photodiode structure designed for 840 nm operation exhibited a quantum efficiency of 50%. High- speed characterization of these devices revealed an estimated 50 GHz bandwidth, corresponding to a BWE product of 25 GHz. To the best of our knowledge

  7. Numerical investigation of the electric field distribution and the power deposition in the resonant cavity of a microwave electrothermal thruster

    Directory of Open Access Journals (Sweden)

    Mehmet Serhan Yildiz

    2017-04-01

    Full Text Available Microwave electrothermal thruster (MET, an in-space propulsion concept, uses an electromagnetic resonant cavity as a heating chamber. In a MET system, electromagnetic energy is converted to thermal energy via a free floating plasma inside a resonant cavity. To optimize the power deposition inside the cavity, the factors that affect the electric field distribution and the resonance conditions must be accounted for. For MET thrusters, the length of the cavity, the dielectric plate that separates the plasma zone from the antenna, the antenna length and the formation of a free floating plasma have direct effects on the electromagnetic wave transmission and thus the power deposition. MET systems can be tuned by adjusting the lengths of the cavity or the antenna. This study presents the results of a 2-D axis symmetric model for the investigation of the effects of cavity length, antenna length, separation plate thickness, as well as the presence of free floating plasma on the power absorption. Specifically, electric field distribution inside the resonant cavity is calculated for a prototype MET system developed at the Bogazici University Space Technologies Laboratory. Simulations are conducted for a cavity fed with a constant power input of 1 kW at 2.45 GHz using COMSOL Multiphysics commercial software. Calculations are performed for maximum plasma electron densities ranging from 1019 to 1021 #/m3. It is determined that the optimum antenna length changes with changing plasma density. The calculations show that over 95% of the delivered power can be deposited to the plasma when the system is tuned by adjusting the cavity length.

  8. Design of coupled cavity with energy modulated electron cyclotron resonance ion source for materials irradiation research

    Directory of Open Access Journals (Sweden)

    Z. Wang (王智

    2012-05-01

    Full Text Available The surface topography of samples after irradiation with heavy ions, protons, and helium ions based on accelerators is an important issue in the study of materials irradiation. We have coupled the separated function radio frequency quadrupole (SFRFQ electrodes and the traditional RFQ electrodes into a single cavity that can provide a 0.8 MeV helium beam for our materials irradiation project. The higher accelerating efficiency has been verified by the successful commissioning of the prototype SFRFQ cavity. An energy modulated electron cyclotron resonance (ECR ion source can achieve a well-bunched beam by loading a sine wave voltage onto the extracted electrodes. Bunching is achieved without the need for an external bunch cavity, which can substantially reduce the cost of the system and the length of the beam line. The coupled RFQ-SFRFQ with an energy modulated ECR ion source will lead to a more compact accelerator system. The conceptual design of this novel structure is presented in this paper.

  9. Multi-cavity locally resonant structure with the low frequency and broad band-gaps

    Directory of Open Access Journals (Sweden)

    Jiulong Jiang

    2016-11-01

    Full Text Available A multi-cavity periodic structure with the characteristic of local resonance was proposed in the paper. The low frequency band-gap structure was comparatively analyzed by the finite element method (FEM and electric circuit analogy (ECA. Low frequency band-gap can be opened through the dual influence of the coupling’s resonance in the cavity and the interaction among the couplings between structures. Finally, the influence of the structural factors on the band-gap was analyzed. The results show that the structure, which is divided into three parts equally, has a broader effective band-gap below the frequency of 200 Hz. It is also proved that reducing the interval between unit structures can increase the intensity of the couplings among the structures. And in this way, the width of band-gap would be expanded significantly. Through the parameters adjustment, the structure enjoys a satisfied sound insulation effect below the frequency of 500Hz. In the area of low frequency noise reduction, the structure has a lot of potential applications.

  10. Automatic segmentation of left ventricle cavity from short-axis cardiac magnetic resonance images.

    Science.gov (United States)

    Yang, Xulei; Song, Qing; Su, Yi

    2017-09-01

    In this paper, a computational framework is proposed to perform a fully automatic segmentation of the left ventricle (LV) cavity from short-axis cardiac magnetic resonance (CMR) images. In the initial phase, the region of interest (ROI) is automatically identified on the first image frame of the CMR slices. This is done by partitioning the image into different regions using a standard fuzzy c-means (FCM) clustering algorithm where the LV region is identified according to its intensity, size and circularity in the image. Next, LV segmentation is performed within the identified ROI by using a novel clustering method that utilizes an objective functional with a dissimilarity measure that incorporates a circular shape function. This circular shape-constrained FCM algorithm is able to differentiate pixels with similar intensity but are located in different regions (e.g. LV cavity and non-LV cavity), thus improving the accuracy of the segmentation even in the presence of papillary muscles. In the final step, the segmented LV cavity is propagated to the adjacent image frame to act as the ROI. The segmentation and ROI propagation are then iteratively executed until the segmentation has been performed for the whole cardiac sequence. Experiment results using the LV Segmentation Challenge validation datasets show that our proposed framework can achieve an average perpendicular distance (APD) shift of 2.23 ± 0.50 mm and the Dice metric (DM) index of 0.89 ± 0.03, which is comparable to the existing cutting edge methods. The added advantage over state of the art is that our approach is fully automatic, does not need manual initialization and does not require a prior trained model.

  11. Ultrasonic transducers with resonant cavities as emitters for air-borne applications

    Directory of Open Access Journals (Sweden)

    Montero De Espinosa Freijo, F.

    2009-08-01

    Full Text Available In this work a new proposal to improve the emission efficiency of air-borne ultrasonic transducers is introduced. A theoretical ultrasonic transducer design is studied using a piezoelectric membrane and a Helmholtz resonator with two acoustic ports. The resonator provides radiation in the acoustic ports in phase with that of the membrane. Several finite element simulations and experimental results are used to study the device. The finite element models were used to compare its behaviour with that of conventional vacuum-cavity transducers. These results show an improvement in the bandwidth reaching a quality factor value of 19. Furthermore, the experimental measurements were used to study the effects of the resonant cavity in the response. Several measurements for different cavity depths were performed. The results show an improvement of 25 dB in the emitted pressure through tuning the transducer.

    En este trabajo se presenta una nueva propuesta para mejorar la eficiencia de transductores ultrasónicos acoplados a aire. Para este estudio se ha empleado un diseño teórico de transductor ultrasónico que utiliza una membrana piezoeléctrica y un resonador de Helmholtz con dos puertos acústicos. El resonador hace que la radiación en los puertos acústicos se encuentre en fase con la producida por la membrana. Para estudiar el dispositivo se utilizaron resultados obtenidos mediante programas de elementos finitos y resultados experimentales. Por un lado, los modelos de elementos finitos se utilizaron para comparar el comportamiento del dispositivo con el de transductores convencionales con cavidades al vacío. Estos resultados indican una mejora en el ancho de banda alcanzando valores de factor de calidad de 19. Por otro lado, los resultados experimentales se emplearon para identificar los efectos de la cavidad resonante en el funcionamiento del dispositivo. Para ello se realizaron varias medidas utilizando ciertas profundidades de cavidad

  12. Label-Free, Single Molecule Resonant Cavity Detection: A Double-Blind Experimental Study

    Directory of Open Access Journals (Sweden)

    Maria V. Chistiakova

    2015-03-01

    Full Text Available Optical resonant cavity sensors are gaining increasing interest as a potential diagnostic method for a range of applications, including medical prognostics and environmental monitoring. However, the majority of detection demonstrations to date have involved identifying a “known” analyte, and the more rigorous double-blind experiment, in which the experimenter must identify unknown solutions, has yet to be performed. This scenario is more representative of a real-world situation. Therefore, before these devices can truly transition, it is necessary to demonstrate this level of robustness. By combining a recently developed surface chemistry with integrated silica optical sensors, we have performed a double-blind experiment to identify four unknown solutions. The four unknown solutions represented a subset or complete set of four known solutions; as such, there were 256 possible combinations. Based on the single molecule detection signal, we correctly identified all solutions. In addition, as part of this work, we developed noise reduction algorithms.

  13. Determination of Activated Carbon Residual Life using a Microwave Cavity Resonator

    International Nuclear Information System (INIS)

    Mason, A; Wylie, S; Shaw, A; Al-Shamma'a, A I; Thomas, A; Keele, H

    2011-01-01

    This paper presents the continuation of work conducted jointly between Dstl and LJMU. This unique body of work has been, largely, concerned with detecting the residual life of high performance filter materials using electromagnetic (EM) waves within a resonant cavity. Past work has considered both HEPA [1] and ASZM-TEDA[2] activated carbon filter materials. This paper continues the later work, considering the response of ASZM-TEDA activated carbon through the co-ageing of two distinct batches of the material. The paper briefly introduces activated carbon, discusses theory relevant to the work and the methodology used for investigation. A comprehensive set of results is included which seek to validate this technique for determining the residual lifespan of activated carbon.

  14. Performance of resonator fiber optic gyroscope using external-cavity laser stabilization and optical filtering

    Science.gov (United States)

    Qiu, Tiequn; Wu, Jianfeng; Strandjord, Lee K.; Sanders, Glen A.

    2014-05-01

    A bench-top resonator fiber optic gyroscope (RFOG) was assembled and tested, showing encouraging progress toward navigation grade performance. The gyro employed a fiber length of 19 meters of polarizing fiber for the sensing coil which was wound on an 11.5 cm diameter PZT cylinder. A bias stability of approximately 0.1 deg/hr was observed over a 2 hour timeframe, which is the best bias stability reported to date in an RFOG to our knowledge. Special care was taken to minimize laser phase noise, including stabilization to an optical cavity which was also used for optical filtering, giving angle random walk (ARW) values in the range of 0.008 deg/rt-hr. The ARW performance and bias stability are within 2x and 10x, respectively, of many civil inertial navigation grade requirements.

  15. Quantification of total pigments in citrus essential oils by thermal wave resonant cavity photopyroelectric spectroscopy.

    Science.gov (United States)

    López-Muñoz, Gerardo A; Antonio-Pérez, Aurora; Díaz-Reyes, J

    2015-05-01

    A general theory of thermal wave resonant cavity photopyroelectric spectroscopy (TWRC-PPE) was recently proposed by Balderas-López (2012) for the thermo-optical characterisation of substances in a condensed phase. This theory is used to quantify the total carotenoids and chlorophylls in several folded and un-folded citrus essential oils to demonstrate the viability of using this technique as an alternative analytical method for the quantification of total pigments in citrus oils. An analysis of variance (ANOVA) reveals significant differences (p spectroscopy can be used to quantify concentrations up to five times higher of total carotenoids and chlorophylls in citrus oils than UV-Vis spectroscopy without sample preparation or dilution. The optical limits of this technique and possible interference are also described. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Low-Cost Resonant Cavity Raman Gas Probe for Multi-Gas Detection

    Science.gov (United States)

    Thorstensen, J.; Haugholt, K. H.; Ferber, A.; Bakke, K. A. H.; Tschudi, J.

    2014-12-01

    Raman based gas sensing can be attractive in several industrial applications, due to its multi-gas sensing capabilities and its ability to detect O_2 and N_2. In this article, we have built a Raman gas probe, based on low-cost components, which has shown an estimated detection limit of 0.5 % for 30 second measurements of N_2 and O_2. While this detection limit is higher than that of commercially available equipment, our estimated component cost is approximately one tenth of the price of commercially available equipment. The use of a resonant Fabry-Pérot cavity increases the scattered signal, and hence the sensitivity, by a factor of 50. The cavity is kept in resonance using a piezo-actuated mirror and a photodiode in a feedback loop. The system described in this article was made with minimum-cost components to demonstrate the low-cost principle. However, it is possible to decrease the detection limit using a higher-powered (but still low-cost) laser and improving the collection optics. By applying these improvements, the detection limit and estimated measurement precision will be sufficient for e.g. the monitoring of input gases in combustion processes, such as e.g. (bio-)gas power plants. In these processes, knowledge about gas compositions with 0.1 % (absolute) precision can help regulate and optimize process conditions. The system has the potential to provide a low-cost, industrial Raman sensor that is optimized for specific gas-detection applications.

  17. A study on utility of magnetic resonance imaging for female pelvic cavity using enteral MRI contrast media

    International Nuclear Information System (INIS)

    Kim, Ham Gyum

    1997-01-01

    For radiological test in soft tissue or neighboring part with same signal intensity, proper test method and equipment shall be selected as needed. In case of female pelvic cavity, ultrasonography or computed tomography alternatively used, but MRI can be more usefully applied to design treatment method or operation plan by improving the diagnostic accuracy and careful observation of lesion characteristics. Magnetic Resonance Imaging using recently developed Enteral MRI contrast media can acquire more diagnostic information than using only intravenous contrast media. Thus this study attempted to examine the utility of anatomic structure and diagnostic acquisition by imaging the female pelvic cavity using Enteral MRI contrast media. As a result of analyzing magnetic resonance imaging after administering Enteral MRI contrast media to pelvic cavity suspect patients, more diagnostic information media could be acquired than only using intravenous contrast. Especially, in the diagnosis of lesion position, shape, distinction from neighboring tissues it is thought that external Enteral MRI contrast media should be used

  18. Nanoscale resonant-cavity-enhanced germanium photodetectors with lithographically defined spectral response for improved performance at telecommunications wavelengths.

    Science.gov (United States)

    Balram, Krishna C; Audet, Ross M; Miller, David A B

    2013-04-22

    We demonstrate the use of a subwavelength planar metal-dielectric resonant cavity to enhance the absorption of germanium photodetectors at wavelengths beyond the material's direct absorption edge, enabling high responsivity across the entire telecommunications C and L bands. The resonant wavelength of the detectors can be tuned linearly by varying the width of the Ge fin, allowing multiple detectors, each resonant at a different wavelength, to be fabricated in a single-step process. This approach is promising for the development of CMOS-compatible devices suitable for integrated, high-speed, and energy-efficient photodetection at telecommunications wavelengths.

  19. A qubit strongly coupled to a resonant cavity: asymmetry of the spontaneous emission spectrum beyond the rotating wave approximation

    Energy Technology Data Exchange (ETDEWEB)

    Cao, X [Department of Physics and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, 361005 (China); You, J Q; Nori, F [Advanced Science Institute, RIKEN, Wako-shi 351-0198 (Japan); Zheng, H, E-mail: xfcao@xmu.edu.cn [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2011-07-15

    We investigate the spontaneous emission (SE) spectrum of a qubit in a lossy resonant cavity. We use neither the rotating-wave approximation nor the Markov approximation. For the weak-coupling case, the SE spectrum of the qubit is a single peak, with its location depending on the spectral density of the qubit environment. Then, the asymmetry (of the location and heights of the two peaks) of the two SE peaks (which are related to the vacuum Rabi splitting) changes as the qubit-cavity coupling increases. Explicitly, for a qubit in a low-frequency intrinsic bath, the height asymmetry of the splitting peaks is enhanced as the qubit-cavity coupling strength increases. However, for a qubit in an Ohmic bath, the height asymmetry of the spectral peaks is inverted compared to the low-frequency bath case. With further increasing the qubit-cavity coupling to the ultra-strong regime, the height asymmetry of the left and right peaks is slightly inverted, which is consistent with the corresponding case of a low-frequency bath. This inversion of the asymmetry arises from the competition between the Ohmic bath and the cavity bath. Therefore, after considering the anti-rotating terms, our results explicitly show how the height asymmetry in the SE spectrum peaks depends on the qubit-cavity coupling and the type of intrinsic noise experienced by the qubit.

  20. Modeling and Simulation of a Resonant-Cavity-Enhanced InGaAs/GaAs Quantum Dot Photodetector

    Directory of Open Access Journals (Sweden)

    W. W. Wang

    2015-01-01

    Full Text Available We simulated and analyzed a resonant-cavity-enhancedd InGaAs/GaAs quantum dot n-i-n photodiode using Crosslight Apsys package. The resonant cavity has a distributed Bragg reflector (DBR at one side. Comparing with the conventional photodetectors, the resonant-cavity-enhanced photodiode (RCE-PD showed higher detection efficiency, faster response speed, and better wavelength selectivity and spatial orientation selectivity. Our simulation results also showed that when an AlAs layer is inserted into the device structure as a blocking layer, ultralow dark current can be achieved, with dark current densities 0.0034 A/cm at 0 V and 0.026 A/cm at a reverse bias of 2 V. We discussed the mechanism producing the photocurrent at various reverse bias. A high quantum efficiency of 87.9% was achieved at resonant wavelength of 1030 nm with a FWHM of about 3 nm. We also simulated InAs QD RCE-PD to compare with InGaAs QD. At last, the photocapacitance characteristic of the model has been discussed under different frequencies.

  1. AZO/Ag/AZO anode for resonant cavity red, blue, and yellow organic light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Gentle, A. R., E-mail: angus.gentle@uts.edu.au; Smith, G. B. [School of Mathematical and Physical Sciences and Institute of Nanoscale Technology, University of Technology Sydney, P.O. Box 123, Broadway, New South Wales 2007 (Australia); Yambem, S. D.; Burn, P. L.; Meredith, P. [Centre for Organic Photonics and Electronics, School of Chemistry and Molecular Biosciences and School of Mathematics and Physics, The University of Queensland, St Lucia, Queensland 4072 (Australia)

    2016-06-28

    Indium tin oxide (ITO) is the transparent electrode of choice for organic light-emitting diodes (OLEDs). Replacing ITO for cost and performance reasons is a major drive across optoelectronics. In this work, we show that changing the transparent electrode on red, blue, and yellow OLEDs from ITO to a multilayer buffered aluminium zinc oxide/silver/aluminium zinc oxide (AZO/Ag/AZO) substantially enhances total output intensity, with better control of colour, its constancy, and intensity over the full exit hemisphere. The thin Ag containing layer induces a resonant cavity optical response of the complete device. This is tuned to the emission spectra of the emissive material while minimizing internally trapped light. A complete set of spectral intensity data is presented across the full exit hemisphere for each electrode type and each OLED colour. Emission zone modelling of output spectra at a wide range of exit angles to the normal was in excellent agreement with the experimental data and hence could, in principle, be used to check and adjust production settings. These multilayer transparent electrodes show significant potential for both eliminating indium from OLEDs and spectrally shaping the emission.

  2. Cavity resonator for dielectric measurements of high-ε, low loss materials, demonstrated with barium strontium zirconium titanate ceramics.

    Science.gov (United States)

    Marksteiner, Quinn R; Treiman, Michael B; Chen, Ching-Fong; Haynes, William B; Reiten, M T; Dalmas, Dale; Pulliam, Elias

    2017-06-01

    A resonant cavity method is presented which can measure loss tangents and dielectric constants for materials with dielectric constant from 150 to 10 000 and above. This practical and accurate technique is demonstrated by measuring barium strontium zirconium titanate bulk ferroelectric ceramic blocks. Above the Curie temperature, in the paraelectric state, barium strontium zirconium titanate has a sufficiently low loss that a series of resonant modes are supported in the cavity. At each mode frequency, the dielectric constant and loss tangent are obtained. The results are consistent with low frequency measurements and computer simulations. A quick method of analyzing the raw data using the 2D static electromagnetic modeling code SuperFish and an estimate of uncertainties are presented.

  3. Noninvasive Vibrational Mode Spectroscopy of Ion Coulomb Crystals through Resonant Collective Coupling to an Optical Cavity Field

    DEFF Research Database (Denmark)

    Dantan, Aurélien; Marler, Joan; Albert, Magnus

    2010-01-01

    We report on a novel noninvasive method to determine the normal mode frequencies of ion Coulomb crystals in traps based on the resonance enhanced collective coupling between the electronic states of the ions and an optical cavity field at the single photon level. Excitations of the normal modes...... are observed through a Doppler broadening of the resonance. An excellent agreement with the predictions of a zero-temperature uniformly charged liquid plasma model is found. The technique opens up for investigations of the heating and damping of cold plasma modes, as well as the coupling between them....

  4. Uniform Field Re-entrant Cylindrical TE[Formula: see text] Cavity for Pulse Electron Paramagnetic Resonance Spectroscopy at Q-band.

    Science.gov (United States)

    Sidabras, Jason W; Reijerse, Edward J; Lubitz, Wolfgang

    2017-01-01

    Uniform field (UF) resonators create a region-of-interest, where the sample volume receives a homogeneous microwave magnetic field ([Formula: see text]) excitation. However, as the region-of-interest is increased, resonator efficiency is reduced. In this work, a new class of uniform field resonators is introduced: the uniform field re-entrant cylindrical TE[Formula: see text] cavity. Here, a UF cylindrical TE[Formula: see text] cavity is designed with re-entrant fins to increase the overall resonator efficiency to match the resonator efficiency maximum of a typical cylindrical TE[Formula: see text] cavity. The new UF re-entrant cylindrical TE[Formula: see text] cavity is designed for Q-band (34 GHz) and is calculated to have the same electron paramagnetic resonance (EPR) signal intensity as a TE[Formula: see text] cavity, a 60% increase in average resonator efficiency [Formula: see text] over the sample, and has a [Formula: see text] profile that is 79.8% uniform over the entire sample volume (98% uniform over the region-of-interest). A new H-type T-junction waveguide coupler with inductive obstacles is introduced that increases the dynamic range of a movable short coupler while reducing the frequency shift by 43% during over-coupling. The resonator assembly is fabricated and tested both on the bench and with EPR experiments. This resonator provides a template to improve EPR spectroscopy for pulse experiments at high frequencies.

  5. Computed tomography and magnetic resonance imaging findings of nasal cavity hemangiomas according to histological type

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Ho; Park, Sun Won; Lim, Myung Kwan; Kim, Yeo Ju; Lee, Ha Young [Dept. of Radiology, Inha University School of Medicine, Incheon (Korea, Republic of); Kim, Soo Jin [Dept. of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Jang, Tae Young [Dept. of Otolaryngology-Head and Neck Surgery, Inha University School of Medicine, Incheon (Korea, Republic of); Kang, Young Hye [Dept. of Radiology, nha University Hospital, Incheon (Korea, Republic of)

    2015-06-15

    To compare computed tomography (CT) and magnetic resonance imaging (MRI) findings between two histological types of nasal hemangiomas (cavernous hemangioma and capillary or lobular capillary hemangioma). CT (n = 20; six pre-contrast; 20 post-enhancement) and MRI (n = 7) images from 23 patients (16 men and seven women; mean age, 43 years; range, 13-73 years) with a pathologically diagnosed nasal cavity hemangioma (17 capillary and lobular capillary hemangiomas and six cavernous hemangiomas) were reviewed, focusing on lesion location, size, origin, contour, enhancement pattern, attenuation or signal intensity (SI), and bony changes. The 17 capillary and lobular hemangiomas averaged 13 mm (range, 4-37 mm) in size, and most (n = 13) were round. Fourteen capillary hemangiomas had marked or moderate early phase enhancement on CT, which dissipated during the delayed phase. Four capillary hemangiomas on MRI showed marked enhancement. Bony changes were usually not seen on CT or MRI (seen on five cases, 29.4%). Half of the lesions (2/4) had low SI on T1-weighted MRI images and heterogeneously high SI with signal voids on T2-weighted images. The six cavernous hemangiomas were larger than the capillary type (mean, 20.5 mm; range, 10-39 mm) and most had lobulating contours (n = 4), with characteristic enhancement patterns (three centripetal and three multifocal nodular), bony remodeling (n = 4, 66.7%), and mild to moderate heterogeneous enhancement during the early and delayed phases. CT and MRI findings are different between the two histological types of nasal hemangiomas, particularly in the enhancement pattern and size, which can assist in preoperative diagnosis and planning of surgical tumor excision.

  6. Enhanced THz resonance based on the coupling between Fabry–Perot oscillation and dipolar-like resonance in a metamaterial surface cavity

    International Nuclear Information System (INIS)

    Zhang, Yaxin; Xu, Gaiqi; Qiao, Shen; Zhou, Yucong; Wu, Zhenhua; Yang, Ziqiang

    2015-01-01

    We presented an enhanced resonance with ultra-wide band in the terahertz (THz) regime in a THz metamaterial system composed of a pair of circular rings arrays which act as two opposite mirrors. The two opposite mirrors, both of which will induce a dipolar-like resonance under the incident wave, together with the gap between them will constitute a Fabry–Perot cavity which contributes to a Fabry–Perot oscillation in the system. These two kinds of resonant modes, the dipolar-like resonance and Fabry–Perot oscillation, can be coupled with each other in an optimized structure, which leads to an enhanced electromagnetic resonance. From the experimental results, it can be found that such coupling leads to a nearly zero transmission zone with 0.12 THz bandwidth which is much better than individual conventional metamaterial system. This coupling mechanism could provide a new way for the realization of strong resonance, which shows great potential for THz pass-band or stop-band filters, THz resonators, THz absorbers, frequency selective devices and so on. (paper)

  7. Strong Coupling Cavity QED with Gate-Defined Double Quantum Dots Enabled by a High Impedance Resonator

    Directory of Open Access Journals (Sweden)

    A. Stockklauser

    2017-03-01

    Full Text Available The strong coupling limit of cavity quantum electrodynamics (QED implies the capability of a matterlike quantum system to coherently transform an individual excitation into a single photon within a resonant structure. This not only enables essential processes required for quantum information processing but also allows for fundamental studies of matter-light interaction. In this work, we demonstrate strong coupling between the charge degree of freedom in a gate-defined GaAs double quantum dot (DQD and a frequency-tunable high impedance resonator realized using an array of superconducting quantum interference devices. In the resonant regime, we resolve the vacuum Rabi mode splitting of size 2g/2π=238  MHz at a resonator linewidth κ/2π=12  MHz and a DQD charge qubit decoherence rate of γ_{2}/2π=40  MHz extracted independently from microwave spectroscopy in the dispersive regime. Our measurements indicate a viable path towards using circuit-based cavity QED for quantum information processing in semiconductor nanostructures.

  8. Study of Nb-Cu 1.3 GHz SRF cavity resonators for future particle accelerators

    CERN Document Server

    Amelin, Kirill

    2017-01-01

    Niobium-coated superconducting radio-frequency cavities have a number of advantages over cavities made from bulk niobium. Cavities coated with high-power impulse magnetron sputtering are tested at CERN in order to optimize the coating and study the Q-slope that limits the performance. To accurately measure the quality factor as a function of accelerating field, it is important to have good matching between an input antenna and a cavity impedance. To improve the matching, a variable coupler that changes the length of the antenna can be used. We have shown that the Q-factor of the input antenna can be changed between $10^7-10^{11}$ by moving the antenna, which should allow to achieve critical coupling with a cavity. This technology could be used in future measurements, so that reflections are always minimized.

  9. Computer program for calculating the resonant frequency, shunt impedance and quality factor of a pill-box cavity in a storage ring

    International Nuclear Information System (INIS)

    Aguero, V.M.; Ng, K.Y.

    1983-10-01

    Keil and Zotter have analyzed the electromagnetic fields excited by the longitudinal density fluctuations of an unbunched relativistic particle beam drifting in a corrugated vacuum chamber of circular cross section. At higher frequencies, these corrugations become resonant cavities. Zotter has written a computer program known as KN7C to compute the resonant frequencies. However, in the actual use of KN7C, some difficulties are encountered. To surmount these difficulties, the program known as CAVITY was written to analyze this pill-box shaped resonant cavity. Although there are many input variables to this program, only two are essential and need to be specified. They are BD = b/d = the ratio of the circular beampipe radius to that of the pill-box cavity and GD = g/d where g is the length of the cavity. When they are specified, CAVITY will print out the dimensionless normalized fundamental resonant frequency FD, shunt impedance Z and figure of merit Q. From these, the actual resonant frequency, shunt impedance and figure of merit can be deduced. The program is described and a listing is provided

  10. Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source

    Science.gov (United States)

    Lunin, A.; Khabiboulline, T.; Solyak, N.; Sukhanov, A.; Yakovlev, V.

    2018-02-01

    Construction of the Linac Coherent Light Source II (LCLS-II) is underway for the world's first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw) mode. The linac is segmented into four sections named as L 0 , L 1 , L 2 , and L 3 . Two 3.9 GHz cryomodules, each housing of eight third-harmonic cavities similar to the cavities developed for the European X-ray Free Electron Laser (XFEL), will be used in section L 1 of the linac for linearizing the longitudinal beam profile. In this paper, we present a study of trapped high order modes (HOMs) excited by a cw electron beam in the third-harmonic cavities of the LCLS-II linac. A detailed comparison of the original XFEL design and the LCLS-II design with a modified end group is performed in order to estimate the effect of a reduced beam pipe aperture on the efficiency of HOM damping. Furthermore, we apply a statistical analysis of the eigenmode spectrum for the estimation of the probability of resonant HOM losses and influence of HOMs on beam dynamics.

  11. Characterization of etch pits found on a large-grain bulk niobium superconducting radio-frequency resonant cavity

    Directory of Open Access Journals (Sweden)

    Xin Zhao

    2010-12-01

    Full Text Available The performance of superconducting radio-frequency (SRF resonant cavities made of bulk niobium is limited by nonlinear localized effects. Surface analysis of regions of higher power dissipation is thus of intense interest. Such areas (referred to as “hotspots” were identified in a large-grain single-cell cavity that had been buffered-chemical polished and dissected for examination by high resolution electron microscopy, electron backscattered diffraction microscopy (EBSD, and optical microscopy. Pits with clearly discernible crystal facets were observed in both “hotspot” and “coldspot” specimens. The pits were found in-grain, at bicrystal boundaries, and on tricrystal junctions. They are interpreted as etch pits induced by crystal defects (e.g. dislocations. All coldspots examined had a qualitatively lower density of etch pits or relatively smooth tricrystal boundary junctions. EBSD mapping revealed the crystal orientation surrounding the pits. Locations with high pit density are correlated with higher mean values of the local average misorientation angle distributions, indicating a higher geometrically necessary dislocation content. In addition, a survey of the samples by energy dispersive x-ray analysis did not show any significant contamination of the samples’ surface. The local magnetic field enhancement produced by the sharp-edge features observed on the samples is not sufficient to explain the observed degradation of the cavity quality factor, which starts at peak surface magnetic field as low as 20 mT.

  12. Nuclear magnetic resonance-based determination of dioxygen binding sites in protein cavities

    DEFF Research Database (Denmark)

    Kitahara, Ryo; Sakuraba, Shun; Kameda, Tomoshi

    2018-01-01

    The location and ligand accessibility of internal cavities in cysteine-free wild-type T4 lysozyme was investigated using O2 gas-pressure NMR spectroscopy and molecular dynamics (MD) simulation. Upon increasing the concentration of dissolved O2 in solvent to 8.9 mM, O2 -induced paramagnetic relaxa...

  13. Studies of niobium and development of niobium resonant RF cavities for accelerator driven system

    International Nuclear Information System (INIS)

    Mondal, Jayanta

    2013-01-01

    The present approach for the fabrication of superconducting radio frequency (SRF) cavities is to roll and deep draw sheets of polycrystalline high-purity niobium. Jefferson Laboratory pioneered the use of large-grain/single-crystal Nb directly sliced from an ingot for the fabrication of single-crystal high-purity Nb SRF cavities. The large grain/single crystal niobium has several potential advantages over the polycrystalline niobium and has become a viable alternative to the standard fine grain (ASTM grain size>6 μm), high purity (RRR ≥ 250 ) niobium for the fabrication of high-performance SRF cavities for particle accelerators. The present study includes the prototype single cell low beta cavity design, fabrication, EB welding and low temperature RF test at 2K. In this study also the medium field Q-Slope has been analyzed with the help of an added non linear term in Heabel's analytical model and a linear increase of surface resistance Rs with the magnetic field

  14. Double resonant absorption measurement of acetylene symmetric vibrational states probed with cavity ring down spectroscopy

    NARCIS (Netherlands)

    Karhu, J.; Nauta, J.; Vainio, M.; Metsala, M.; Hoekstra, S.; Halonen, L.

    2016-01-01

    A novel mid-infrared/near-infrared double resonant absorption setup for studying infrared-inactive vibrational states is presented. A strong vibrational transition in the mid-infrared region is excited using an idler beam from a singly resonant continuous-wave optical parametric oscillator, to

  15. Performance test of a vertically-directed electric-field cavity resonator made for the rapid gelation apparatus with microwave heating

    International Nuclear Information System (INIS)

    Yamagishi, Shigeru; Ogawa, Toru; Hasegawa, Atsushi.

    1996-06-01

    A cavity resonator with vertically-directed electric field was produced and attached to 'the rapid gelation apparatus with microwave heating' previously reported. Using the rapid gelation apparatus, drops of a simulated solution and of U-containing solutions for internal gelation were heated. The results indicated that the heating required for gelation of the U-containing solutions was possible. However, the electric field strength in the cavity resonator at that time was comparable to that causing the discharge due to the gaseous ammonia released from the heated drops. As a result, gel microspheres were not obtained in a stable state. The discussion suggests that the stable gelation would be realized by improving the cavity resonator shape and/or by modifying the power supply accompanied with using a power stabilizer. (author)

  16. Aperiodic signals processing via parameter-tuning stochastic resonance in a photorefractive ring cavity

    Directory of Open Access Journals (Sweden)

    Xuefeng Li

    2014-04-01

    Full Text Available Based on solving numerically the generalized nonlinear Langevin equation describing the nonlinear dynamics of stochastic resonance by Fourth-order Runge-Kutta method, an aperiodic stochastic resonance based on an optical bistable system is numerically investigated. The numerical results show that a parameter-tuning stochastic resonance system can be realized by choosing the appropriate optical bistable parameters, which performs well in reconstructing aperiodic signals from a very high level of noise background. The influences of optical bistable parameters on the stochastic resonance effect are numerically analyzed via cross-correlation, and a maximum cross-correlation gain of 8 is obtained by optimizing optical bistable parameters. This provides a prospective method for reconstructing noise-hidden weak signals in all-optical signal processing systems.

  17. The 938 MHz resonant damping loops for the 200 MHz SPS travelling wave cavities

    CERN Document Server

    Caspers, F

    2012-01-01

    Measurements of the beam stability in the SPS in 1982 - 1983 have shown a transversal instability for high intensity beams [1]. The fact that this related technical note is published nearly 30 years later, is related to the revival of interest in the frame of SPS impedance evaluation for LS1. Until now there was just a barely known paper folder available which could be consulted on request. The instability mentioned above was identified from beam measurements as raised by a deflecting mode at approximately 940 MHz in the 200 MHz travelling wave cavities of the SPS. Estimates showed that an attenuation of this particular mode by 20 dB would be desirable. In order to achieve this attenuation some vacuum ports on top of the cavities were available. For the damping devices three requirements had to be met: - sufficient damping at about 940 MHz - no serious change of cavity input VSWR at 200 MHz - no water cooling requirement for this higher order mode coupler.

  18. Magnetic resonance imaging of syrinx cavity. Differentiation between syrinx with spinal cord tumor and without tumor

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Teruo; Inoue, Yuichi; Nemoto, Yutaka

    1987-12-01

    Syrinx cavity may result from a number of intramedullary tumors or non-neoplastic conditions such as Chiari malformation, trauma and meningitis. The surgical procedure to repair the syrinx is quite different between the cases with spinal cord tumor and without tumor. Therefore, it is important to determine whether syrinx is associated with tumor or not before surgery. We reviewed MR images of 26 cases with syrinx cavity; 20 of which were not associated with tumor (12 Chiari malformation, 5 trauma, 1 meningitis, 1 hydrocephalus, 1 idiopathic) and 6 of which were associated with intramedullary tumor (3 ependymoma, 2 astrocytoma, 1 hemangioendothelioma). The syrinx showed low signal in all 26 cases on T1 weighted images (SE 600/40). All 6 cases with syrinx associated with intramedullary tumor showed high intensity on T2 weighted images (SE 2000/120). On the other hand, the syrinx of 19 of 20 cases with no tumor condition showed reduced intensity on T2 weighted images. Only one post-traumatic small syrinx showed high signal. This was quite different between the cases with spinal cord tumor and without tumor. Therefore, when the syrinx cavity shows high signal on T2 weighted images, an intramedullary tumor is strongly suggested.

  19. Cavity QED experiments with a whispering-gallery-mode bottle resonator

    International Nuclear Information System (INIS)

    O'Shea, D.

    2013-01-01

    The interaction of a two-level atom with a single mode of the quantized electromagnetic field constitutes one of the most fundamental systems investigated in quantum optics. We have pursued such an investigation where rubidium atoms are strongly coupled to the modes of a whispering-gallery-mode (WGM) resonator that is itself interfaced with an optical fiber. In order to facilitate studies of this atom-light interaction, an experimental apparatus was constructed around a novel type of WGM resonator developed in our group. The spectral and spatial mode structure of this resonator yield an intriguing atom-light response arising principally from the existence of two frequency-degenerate modes. This thesis reports on high resolution experiments studying the transmission and reflection spectra of modes with a high quality factor (Q=10 7 -10 8 ) in our WGM resonator. Light is coupled into and out of WGMs by frustrated total internal reflection using an optical nanofiber. The atom-light interaction is facilitated by an atomic fountain that delivers a cloud of atoms to the location of the resonator. At random moments, single-atoms are clearly observed transiting the evanescent field of the resonator modes with a transit time of a few microseconds. A high-speed experimental control system was developed to firstly detect the coupling of individual atoms to the resonator and secondly to perform time-resolved spectroscopy on the strongly coupled atom-resonator system. Spectral measurements clearly resolve an atom-induced change in the resonant transmission of the coupled system (65% absolute change) that is much larger than predicted in the standard Jaynes-Cummings model (25% absolute change) and that has thus far not been observed. To gain further insight, we experimentally explored the properties of the interaction and performed supporting simulations. Spectroscopy was performed on the atom-resonator system using two nanofibers to in- and out-couple light for probing

  20. Tailoring optical resonant cavity modes in SnO2 microstructures through doping and shape engineering

    Science.gov (United States)

    García-Tecedor, M.; Maestre, D.; Cremades, A.; Piqueras, J.

    2017-10-01

    Optical resonances are effectively tailored by engineering size, morphology and doping in tin oxide microstructures. The use of Cr shifts the light confinement to the near-infrared region, as compared to the undoped microstructures, while achieving good Q and F factors. Other issues, such as appropriate thickness to width ratio, allow the selection of Fabry-Pérot or Whispering Gallery modes, or the appearance of a combination of both kinds of resonances in the same microstructure. Morphology variability would contribute with flexibility in the design of systems for different applications, while combining the observed waveguiding behavior with the optical resonances in the same material is an advantage for applications based in a monolithic design. Refraction index of Cr doped tin oxide has been obtained.

  1. High quantum efficiency N-structure type-II superlattice mid-wavelength infrared detector with resonant cavity enhanced design

    Science.gov (United States)

    Wu, Haoyue; Xu, Yun; Li, Jian; Jiang, Yu; Bai, Lin; Yu, Hailong; Fu, Dong; Zhu, Haijun; Song, Guofeng

    2017-05-01

    We propose a resonant cavity enhanced (RCE) N-structure type-II superlattice (T2SL) mid-wavelength infrared (MWIR) photodetector which can be used for the detection of methane gas at 3.3 μm. The theoretical analysis of quantum efficiency (QE) shows that the peak QE can be enhanced from 0.45 to 0.80 at 3.3 μm after 12 period AlAs0.09Sb0.91/GaSb DBR is introduced to the N-structure T2SL detector and QE exhibits the narrow bandwidth characteristic near the target wavelength. By analyzing the refractive indices of different materials and the reflectance of different DBRs, we also discuss how to determine the component materials of quarter-wavelength DBR reflectors.

  2. Resonant cavities for efficient LT-GaAs photoconductors operating at λ = 1550 nm

    Directory of Open Access Journals (Sweden)

    M. Billet

    2016-10-01

    Full Text Available We show that photoconductors based on low-temperature-grown GaAs (LT-GaAs can be efficiently operated by 1.55 μm telecom wavelength by using metallic mirror based optical cavities. Two different semi-transparent front mirrors are compared: the first one is a thin gold layer, whereas the second one consists of a gold grating. Light absorption in grating mirror based optical cavities is numerically, analytically, and experimentally investigated allowing for an appropriate optical design. We show a 3 times improvement of the LT-GaAs photoconductor photoresponse by using, as front mirror, the gold grating once compared with the thin gold layer. It reaches around 0.5 mA/W under continuous wave, whereas a transient photoresistivity (Ron as low as 5 Ω is deduced from dc photocurrents measured under femtosecond pulsed laser excitation. This work paves the way to efficient and reliable optoelectronics systems for GHz or THz waves sampling driven by 1.55 μm pulsed lasers widely available.

  3. DWDM channel spacing tunable optical TDM carrier from a mode-locked weak-resonant-cavity Fabry-Perot laser diode based fiber ring.

    Science.gov (United States)

    Peng, Guo-Hsuan; Chi, Yu-Chieh; Lin, Gong-Ru

    2008-08-18

    A novel optical TDM pulsed carrier with tunable mode spacing matching the ITU-T defined DWDM channels is demonstrated, which is generated from an optically injection-mode-locked weak-resonant-cavity Fabry-Perot laser diode (FPLD) with 10%-end-facet reflectivity. The FPLD exhibits relatively weak cavity modes and a gain spectral linewidth covering >33.5 nm. The least common multiple of the mode spacing determined by both the weak-resonant-cavity FPLD and the fiber-ring cavity can be tunable by adjusting length of the fiber ring cavity or the FPLD temperature to approach the desired 200GHz DWDM channel spacing of 1.6 nm. At a specific fiber-ring cavity length, such a least-common- multiple selection rule results in 12 lasing modes between 1532 and 1545 nm naturally and a mode-locking pulsewidth of 19 ps broadened by group velocity dispersion among different modes. With an additional intracavity bandpass filter, the operating wavelength can further extend from 1520 to 1553.5 nm. After channel filtering, each selected longitudinal mode gives rise to a shortened pulsewidth of 12 ps due to the reduced group velocity dispersion. By linear dispersion compensating with a 55-m long dispersion compensation fiber (DCF), the pulsewidth can be further compressed to 8 ps with its corresponding peak-to-peak chirp reducing from 9.7 to 4.3 GHz.

  4. Ovenized microelectromechanical system (MEMS) resonator

    Science.gov (United States)

    Olsson, Roy H; Wojciechowski, Kenneth; Kim, Bongsang

    2014-03-11

    An ovenized micro-electro-mechanical system (MEMS) resonator including: a substantially thermally isolated mechanical resonator cavity; a mechanical oscillator coupled to the mechanical resonator cavity; and a heating element formed on the mechanical resonator cavity.

  5. Theoretical and experimental investigation of electron beam acceleration and submillimeter wave generation in cyclotron resonant cavities

    Science.gov (United States)

    Luhmann, N. C., Jr.; McDermott, D. B.

    1991-06-01

    Many millimeter wave generation interactions have been under development. A prebunched high harmonic gyrotron has extended the power level of our previous high harmonic gyrotrons. Also, the instabilities in gyro traveling wave tube (TWT) amplifiers are now understood and methods have been formulated to stabilize them (multi severs). This work has led to the design of a very high power (500 kW) harmonic gyro-TWT using a conventional MIG, which we plan to build in the next few years. We have also been active in the development of an extremely high power millimeter wave source, the CARM: (1) we have designed and simulated a 300 MW, 17 GHz device for the next generation high gradient RF linac; (2) we actively participated in LLNL's 250 GHz CARM project; and (3) we are continuing to fabricate at UCLA a 400 kV, 10 MW proof of principle CARM, which will use Bragg reflectors for its requisite frequency selective cavity. We have advanced the state-of-the-art of Bragg reflectors by testing high mode purity Bragg reflectors. In addition, we have designed and are well into the construction of a very high power, wideband continuous tunability gyro backward wave oscillator (BWO) and a very efficient gyro-klystron amplifier.

  6. Ionizing Radiation Detectors Based on Ge-Doped Optical Fibers Inserted in Resonant Cavities

    Directory of Open Access Journals (Sweden)

    Saverio Avino

    2015-02-01

    Full Text Available The measurement of ionizing radiation (IR is a crucial issue in different areas of interest, from environmental safety and industrial monitoring to aerospace and medicine. Optical fiber sensors have recently proven good candidates as radiation dosimeters. Here we investigate the effect of IR on germanosilicate optical fibers. A piece of Ge-doped fiber enclosed between two fiber Bragg gratings (FBGs is irradiated with gamma radiation generated by a 6 MV medical linear accelerator. With respect to other FBG-based IR dosimeters, here the sensor is only the bare fiber without any special internal structure. A near infrared laser is frequency locked to the cavity modes for high resolution measurement of radiation induced effects on the fiber optical parameters. In particular, we observe a variation of the fiber thermo-optic response with the radiation dose delivered, as expected from the interaction with Ge defect centers, and demonstrate a detection limit of 360 mGy. This method can have an impact in those contexts where low radiation doses have to be measured both in small volumes or over large areas, such as radiation therapy and radiation protection, while bare optical fibers are cheap and disposable.

  7. Decrease of the surface resistance in superconducting niobium resonator cavities by the microwave field

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Dhakal, Pashupati [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Gurevich, Alexander V. [Old Dominion University, Norfolk, VA (United States)

    2014-03-03

    Measurements of the quality factor, Q, of Nb superconducting microwave resonators often show that Q increases by {approx_equal} 10%–30% with increasing radio-frequency (rf) field, H, up to {approx} 15-20 mT. Recent high temperature heat treatments can amplify this rf field-induced increase of Q up to {approx_equal} 50%–100% and extend it to much higher fields, but the mechanisms of the enhancement of Q(H) remain unclear. Here, we suggest a method to reveal these mechanisms by measuring temperature dependencies of Q at different rf field amplitudes. We show that the increase of Q(H) does not come from a field dependent quasi-particles activation energy or residual resistance, but rather results from the smearing of the density of state by the rf field.

  8. Generation of strong electromagnetic power at 35 GHz from the interaction of a resonant cavity with a relativistic electron beam generated by a free electron laser

    International Nuclear Information System (INIS)

    Lefevre, Thibaut

    2000-01-01

    The next generation of electron-positron linear colliders must reach the TeV energy range. For this, one requires an adequate RF power source to feed the accelerating cavities of the collider. One way to generate this source is to use the Two Beam Accelerator concept in which the RF power is produced in resonant cavities driven by an intense bunched beam. In this thesis, I present the experimental results obtained at the CEA/CESTA using an electron beam generated by an induction linac. First, some studies were performed with the LELIA induction linac (2.2 MeV, 1 kA, 80 ns) using a Free Electron Laser (FEL) as a buncher at 35 GHz. A second part relates the experiment made with the PIVAIR induction linac (7 MeV, 1 kA, 80 ns) in order to measure the RF power extracted from a resonant cavity at 35 GHz, which is driven by the bunches produced in the FEL. One can also find a simple theoretical modeling of the beam-cavity interaction, and the numerical results dealing with the design of the cavity we tested. (author) [fr

  9. Hot-cavity studies for the Resonance Ionization Laser Ion Source

    International Nuclear Information System (INIS)

    Henares, J.L.; Lecesne, N.; Hijazi, L.; Bastin, B.; Kron, T.; Lassen, J.; Le Blanc, F.; Leroy, R.; Osmond, B.; Raeder, S.; Schneider, F.; Wendt, K.

    2016-01-01

    The Resonance Ionization Laser Ion Source (RILIS) has emerged as an important technique in many Radioactive Ion Beam (RIB) facilities for its reliability, and ability to ionize target elements efficiently and element selectively. GISELE is an off-line RILIS test bench to study the implementation of an on-line laser ion source at the GANIL separator facility. The aim of this project is to determine the best technical solution which combines high selectivity and ionization efficiency with small ion beam emittance and stable long term operation. The ion source geometry was tested in several configurations in order to find a solution with optimal ionization efficiency and beam emittance. Furthermore, a low work function material was tested to reduce the contaminants and molecular sidebands generated inside the ion source. First results with ZrC ionizer tubes will be presented. Furthermore, a method to measure the energy distribution of the ion beam as a function of the time of flight will be discussed.

  10. Design and Performance of (Au,Yb)/ZnS/InSe/C Heterojunctions as Plasmon Resonators, Photodetectors and Microwave Cavities

    Science.gov (United States)

    Khusayfan, Najla M.; Khanfar, Hazem K.

    2017-03-01

    In this study, we concentrate on the design and characterization of the hybrid isotype (Au, Yb)/ZnS/InSe/C devices. The thin film devices that are prepared by using the vacuum deposition technique are characterized by means of x-ray diffraction, energy dispersive x-ray analysis, optical and dielectric spectroscopy, current-voltage characteristics and impedance spectroscopy techniques. The techniques allow determining the preferred crystallinity at the interfaces, the lattice match/mismatch ratios, the atomic compositions, the energy band gap shifts, the valence and conduction band offsets, the barrier heights at the Schottky shoulders (Au/ZnS and InSe/C) of the hybrid structure and the plasmonic interaction at the ZnS/InSe and (Au, Yb)/ZnS/InSe interfaces. The hybrid isotype device is found to exhibit photosensing features presented by a responsivity of ˜2.0 A/W, external quantum efficiencies (EQE) and internal quantum efficiencies (IQE) of 395% and 2493%, at basing voltage of 0.3 V, respectively. In addition, the dielectric spectra modeling reveals a plasmon-electron interaction of resonance frequencies in the range of 0.31-5.26 GHz and drift mobility of ˜212 cm2/Vs and 106 cm2/Vs for the Au/ZnS/InSe and Yb/ZnS/InSe, respectively. Moreover, the impedance spectroscopy studies confirm the correctness of the dielectric modeling nominating the Yb/ZnS/InSe/C devices as photodetectors, plasmon resonators and microwave cavities.

  11. Acoustic field of an ultrasonic cavity resonator with two open ends: Experimental measurements and lattice Boltzmann method modeling

    Science.gov (United States)

    Shan, Feng; Tu, Juan; Cheng, Jianchun; Zhang, Dong; Li, Faqi; Wang, Zhibiao

    2017-03-01

    High-intensity focused ultrasound (HIFU) has become an attractive therapeutic tool for noninvasive tumor treatment. The key component of HIFU systems is the acoustic transducer, which generates a focal region of high-intensity focused ultrasonic energy. A key determinant of safety in HIFU treatment is the size of the focal region. To achieve subwavelength focusing, we previously investigated the feasibility of an ultrasonic spherical cavity resonator (USCR) with two open ends. To further investigate the properties of the USCR, experiments and simulations were performed to comprehensively characterize the acoustic field generated. The emphasis was on the field formation process, the pressure distribution, the frequency dependence, and the acoustic nonlinearity. As a novel simulation approach, an axisymmetric isothermal multi-relaxation-time lattice Boltzmann method (MRT-LBM) model was used to numerically analyze the acoustic field. The reliability of this model was verified by comparing the results generated with those from experiments. The MRT-LBM model gave new insight into conventional acoustic numerical simulations and provided significant indications for USCR parameter optimization. The USCR demonstrated its feasibility for application in HIFU treatment or in other fields that demand high-precision focusing.

  12. Design and Analysis of Enhanced Modulation Response in Integrated Coupled Cavities DBR Lasers Using Photon-Photon Resonance

    Directory of Open Access Journals (Sweden)

    Paolo Bardella

    2016-01-01

    Full Text Available In the last few decades, various solutions have been proposed to increase the modulation bandwidth and, consequently, the transmission bit-rate of semiconductor lasers. In this manuscript, we discuss a design procedure for a recently proposed laser cavity realized with the monolithic integration of two distributed Bragg reflector (DBR lasers allowing one to extend the modulation bandwidth. Such an extension is obtained introducing in the dynamic response a photon-photon resonance (PPR at a frequency higher than the modulation bandwidth of the corresponding single-section laser. Design guidelines will be proposed, and dynamic small and large signal simulations results, calculated using a finite difference traveling wave (FDTW numerical simulator, will be discussed to confirm the design results. The effectiveness of the design procedure is verified in a structure with PPR frequency at 35 GHz allowing one to obtain an open eye diagram for a non-return-to-zero (NRZ digital signal up to 80 GHz . Furthermore, the investigation of the rich dynamics of this structure shows that with proper bias conditions, it is possible to obtain also a tunable self-pulsating signal in a frequency range related to the PPR design.

  13. Computed tomography and magnetic resonance for the advanced imaging of the normal nasal cavity and paranasal sinuses of the koala (Phascolarctos cinereus).

    Science.gov (United States)

    Bercier, Marjorie; Alexander, Kate; Gorow, April; Pye, Geoffrey W

    2014-12-01

    The objective of this study is to describe computed tomography (CT) and magnetic resonance (MR) for the cross-sectional imaging of the normal anatomy of the nasal cavity and paranasal sinuses of the koala (Phascolarctos cinereus), to provide reference figures for gross anatomy with corresponding CT and MR images and to compare the features of the nasal cavity and paranasal sinuses of the normal koala with that reported in other domestic species. Advanced imaging can be used to aid in diagnosis, to plan surgical intervention, and to monitor therapeutic responses to diseases of the nasal passages in koalas. One clinically normal koala was anesthetized twice for the separate acquisition of dorsal CT scan images and transverse, dorsal, and sagittal MR images of its nasal cavity and paranasal sinuses. Sagittal and transverse CT planes were reformatted. Three fresh koala skulls were also transected in one of each transverse, sagittal, and dorsal planes and photographed. The CT and MR images obtained were matched with corresponding gross anatomic images and the normal bone, tissues and airway passages were identified. All anatomic structures were readily identifiable on CT, magnetic resonance imaging (MRI), and gross images. CT and MRI are both valuable diagnostic tools for imaging the nasal cavities and paranasal sinuses of koalas. Images obtained from this project can be used as baseline references for future comparison with diseased koalas to help with diagnosis, surgical intervention, and response to therapy.

  14. Amplification of an Autodyne Signal in a Bistable Vertical-Cavity Surface-Emitting Laser with the Use of a Vibrational Resonance

    Science.gov (United States)

    Chizhevsky, V. N.

    2018-01-01

    For the first time, it is demonstrated experimentally that a vibrational resonance in a polarization-bistable vertical-cavity surface-emitting laser can be used to increase the laser response in autodyne detection of microvibrations from reflecting surfaces. In this case, more than 25-fold signal amplification is achieved. The influence of the asymmetry of the bistable potential on the microvibration-detection efficiency is studied.

  15. The effect of cavity tuning on oxygen beam currents of an A-ECR type 14 GHz electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, O., E-mail: olli.tarvainen@jyu.fi; Orpana, J.; Kronholm, R.; Kalvas, T.; Laulainen, J.; Koivisto, H. [Department of Physics (JYFL), University of Jyväskylä, 40500 Jyväskylä (Finland); Izotov, I.; Skalyga, V. [Institute of Applied Physics, RAS, 46 Ul’yanova St., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina St., 603950 Nizhny Novgorod (Russian Federation); Toivanen, V. [European Organization for Nuclear Research (CERN), 1211 Geneva 23 (Switzerland)

    2016-09-15

    The efficiency of the microwave-plasma coupling plays a significant role in the production of highly charged ion beams with electron cyclotron resonance ion sources (ECRISs). The coupling properties are affected by the mechanical design of the ion source plasma chamber and microwave launching system, as well as damping of the microwave electric field by the plasma. Several experiments attempting to optimize the microwave-plasma coupling characteristics by fine-tuning the frequency of the injected microwaves have been conducted with varying degrees of success. The inherent difficulty in interpretation of the frequency tuning results is that the effects of microwave coupling system and the cavity behavior of the plasma chamber cannot be separated. A preferable approach to study the effect of the cavity properties of the plasma chamber on extracted beam currents is to adjust the cavity dimensions. The results of such cavity tuning experiments conducted with the JYFL 14 GHz ECRIS are reported here. The cavity properties were adjusted by inserting a conducting tuner rod axially into the plasma chamber. The extracted beam currents of oxygen charge states O{sup 3+}–O{sup 7+} were recorded at various tuner positions and frequencies in the range of 14.00–14.15 GHz. It was observed that the tuner position affects the beam currents of high charge state ions up to several tens of percent. In particular, it was found that at some tuner position / frequency combinations the plasma exhibited “mode-hopping” between two operating regimes. The results improve the understanding of the role of plasma chamber cavity properties on ECRIS performances.

  16. A Microbolometer System for Radiation Detection in the THz Frequency Range with a Resonating Cavity Fabricated in the CMOS Technology.

    Science.gov (United States)

    Sesek, Aleksander; Zemva, Andrej; Trontelj, Janez

    2018-02-14

    The THz sensors using microbolometers as a sensing element are reported as one of the most sensitive room-temperature THz detectors suitable for THz imaging and spectroscopic applications. Microbolometer detectors are usually fabricated using different types of the MEMS technology. The patent for the detection system presented in this paper describes a method for microbolometer fabrication using a standard CMOS technology with advanced micromachining techniques. The measured sensitivity of the sensors fabricated by the patented method is 1000 V/W at an optimal frequency and is determined by the performance of a double-dipole antenna and quarter-wavelength resonant cavity. The paper presents a patented method for fabrication of a microbolometer system for radiation detection in the THz frequency range (16). The method is divided into several stages regarding the current silicon micromachining process. Main stages are fabrication of supporting structures for micro bridge, creation of micro cavities and fabrication of Aluminum antenna and Titanium microbolometer. Additional method for encapsulation in the vacuum is described which additionally improves the performance of bolometer. The CMOS technology is utilized for fabrication as it is cost effective and provides the possibility of larger sensor systems integration with included amplification. At other wavelengths (e.g. IR region) thermistors are usually also the receivers with the sensor resistance change provoked by self-heating. In the THz region the energy is received by an antenna coupled to a thermistor. Depending on the specific application requirement, two types of the antenna were designed and used; a narrow-band dipole antenna and a wideband log-periodic antenna. With method described in the paper, the microbolometer detector reaches sensitivities up to 500 V/W and noise equivalent power (NEP) down to 10 pW/√Hz. Additional encapsulation in the vacuum improves its performance at least by a factor of 2

  17. A wide area Bipolar Cascade Resonant Cavity Light Emitting Diode for a Hybrid Range-Intensity Sensor

    Science.gov (United States)

    Turner, Reginald J.

    Autonomous Ground Vehicles (AGV) will require high-speed, real-time three dimensional (3-D) image processing to navigate treacherous terrain in order to complete their assigned mission without a human in the loop. LIDAR scanners of the 3-D variety, provide the necessary area coverage for 3-D image processing, but lack the speed to deliver the collected data for real-time processing. A novel Hybrid Range-Intensity System (HRIS) has been proposed for imaging large swaths of area very rapidly. This system is comprised of two infrared cameras, an illumination source, a control and coordination system to position the cameras, and signal processing algorithms to extract the contour image of the scene. This dissertation focused on the development of an illuminator for the HRIS. This illuminator enables faster image rendering and reduces the potential of errors in return signal data, that could be generated from extremely rough terrain. Four major achievements resulted from this work, which advance the field of 3-D image acquisition. The first is that the TJ is an effective current spreading layer for LEDs with mesa width up to 140 mum and current densities of ˜ 1 x 106A/cm2. The TJ allows fabrication of an efficient illuminator, with required geometry for the HRIS to operate as a real-time 3-D imaging system. Secondly, a design for a Bipolar Cascade-Resonant Cavity Light Emitting Diode (BC-RCLED) has been accomplished, that will illuminate the FOV of the hybrid-ranged intensity system with a single sweep of the beam. This device is capable of producing ˜ 330 mW of output power. Additionally, from this work, key parameters for HRIS design were identified. Using a collection optic with a 15 cm diameter, an HRIS mounting height of 1.5 m, and a detector integration time of 330 msec, a SNR of 20 dB was achieved. Lastly, we demonstrated that the BC-RCLED designed for the HRIS can deliver sufficient energy to produce the required SNR. Also, through parametric analysis, we

  18. Spectrophotometric resonant measurement of wavelength phase dispersion on femtosecond laser cavities and single elements during their fabrication

    Science.gov (United States)

    Bukhshtab, Michael A.

    1996-02-01

    A spectrophotometric reflection technique and measurement results of wavelength phase dispersion on femtosecond laser cavities and distinct elements are reported. In contrast to novel frequency-domain and interferometric Fourier-transform methods, the proposed reflection-based measurement procedure maintains a notably high sensitivity while studying either cavities or single elements. Resolved phase spectrums are evaluated using a standard spectrophotometer with a single-beam reflection attachment.

  19. Magnetic Resonance Image Guided Radiation Therapy for External Beam Accelerated Partial-Breast Irradiation: Evaluation of Delivered Dose and Intrafractional Cavity Motion

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, Sahaja; Fischer-Valuck, Benjamin W.; Mazur, Thomas R.; Curcuru, Austen; Sona, Karl; Kashani, Rojano; Green, Olga; Ochoa, Laura; Mutic, Sasa; Zoberi, Imran; Li, H. Harold; Thomas, Maria A., E-mail: mthomas@radonc.wustl.edu

    2016-11-15

    Purpose: To use magnetic resonance image guided radiation therapy (MR-IGRT) for accelerated partial-breast irradiation (APBI) to (1) determine intrafractional motion of the breast surgical cavity; and (2) assess delivered dose versus planned dose. Methods and Materials: Thirty women with breast cancer (stages 0-I) who underwent breast-conserving surgery were enrolled in a prospective registry evaluating APBI using a 0.35-T MR-IGRT system. Clinical target volume was defined as the surgical cavity plus a 1-cm margin (excluding chest wall, pectoral muscles, and 5 mm from skin). No additional margin was added for the planning target volume (PTV). A volumetric MR image was acquired before each fraction, and patients were set up to the surgical cavity as visualized on MR imaging. To determine the delivered dose for each fraction, the electron density map and contours from the computed tomography simulation were transferred to the pretreatment MR image via rigid registration. Intrafractional motion of the surgical cavity was determined by applying a tracking algorithm to the cavity contour as visualized on cine MR. Results: Median PTV volume was reduced by 52% when using no PTV margin compared with a 1-cm PTV margin used conventionally. The mean (± standard deviation) difference between planned and delivered dose to the PTV (V95) was 0.6% ± 0.1%. The mean cavity displacement in the anterior–posterior and superior–inferior directions was 0.6 ± 0.4 mm and 0.6 ± 0.3 mm, respectively. The mean margin required for at least 90% of the cavity to be contained by the margin for 90% of the time was 0.7 mm (5th-95th percentile: 0-2.7 mm). Conclusion: Minimal intrafractional motion was observed, and the mean difference between planned and delivered dose was less than 1%. Assessment of efficacy and cosmesis of this MR-guided APBI approach is under way.

  20. HF power couplers for pulsed superconducting cavity resonators; Coupleurs de puissance HF pour cavites supraconductrices en mode pulse

    Energy Technology Data Exchange (ETDEWEB)

    Jenhani, Hassen [Laboratoire de l' Accelerateur Lineaire, IN2P3-CNRS et Universite de Paris-Sud, BP 34, F-91898 Orsay Cedex (France)

    2006-11-15

    Recent years have seen an impressive improvement in the accelerating gradients obtained in superconducting cavities. Consequently, such cavities have become attractive candidates for large superconducting linear accelerator projects such as the European XFEL and the International Linear Collider (ILC). As a result, there is a strong interest in reducing RF conditioning time and improving the performance of the input power couplers for these cavities. The so-called TTF-III input power coupler, adopted for the XFEL superconducting RF cavities are complex components. In order to better understand the behavior of this component we have performed a series of experiments on a number of such couplers. Initially, we developed a fully automated RF high power test stand for coupler conditioning procedure. Following this, we performed a series of coupler conditioning tests. This has allowed the study of the coupler behavior during processing. A number of experiments were carried out to evaluate the in-situ baking effect on the conditioning time. Some of the conditioned couplers were sent to DESY in order to be tested on 9-cells TESLA cavities under cryogenic conditions. These tests have shown that the couplers in no way limit the cavity performance, even up to gradients of 35 MV/m. The main objective of our coupler studies was the reduction of their conditioning time, which represents one of the most important criteria in the choice of coupler for high energy linacs. Excellent progress in reducing the conditioning time has been demonstrated by making appropriate modifications to the conditioning procedure. Furthermore, special attention was paid to electron generation processes in the couplers, via multipacting. Simulations of this process were made on both the TTF-III coupler and on a new coupler prototype, TTF-V. Experiments aimed at suppressing multipacting were also successfully achieved by using a DC bias on the inner conductor of the co-axial coupler. (author)

  1. Control of Fano resonances in photonic crystal nanobeams side-coupled with nanobeam cavities and their applications to refractive index sensing

    Science.gov (United States)

    Meng, Zi-Ming; Li, Zhi-Yuan

    2018-03-01

    We study the control of Fano resonances in a 2D photonic crystal nanobeam (PCN) side-coupled with a photonic crystal nanobeam cavity (PCNC) by choosing different cavity modes, the position of the photonic bandgap of PCNs and the displacement between PCNs and PCNCs. By increasing the refractive index of the holes and the surrounding medium, it is found that the air mode cavity with even mirror-reflection symmetry holds the highest sensitivity (538 nm/RIU RIU, refractive index unit) and maximal figure of merit (FOM  =  516). Our results can be extended to a practical 3D configuration, where an air-suspended silicon PCN is side-coupled with a PCNC. Although the sensitivity is only 192 nm/RIU for our 3D structures, the maximal FOM is as large as 2095 due to the deep transmission valley. The sensitivity of our PCN–PCNC structures can be further improved by designing PCNCs with electric field concentrated in the air region as much as possible. Our PCN–PCNC structures do not require ultrahigh Q and can be fabricated on the silicon-on-insulator platform, which is compatible with CMOS processing. Therefore, our proposed PCN–PCNC structures provide feasible solutions for realizing label-free sensitive integrated refractive index sensors.

  2. New analytical calculations of the resonance modes in lens-shaped cavities: applications to the calculations of the energy levels and electronic wavefunctions in quantum dots

    International Nuclear Information System (INIS)

    Even, J; Loualiche, S

    2003-01-01

    The problem of the energy levels and electronic wavefunctions in quantum dots is studied in the parabolic coordinates system. A conventional effective mass Hamiltonian is written. For an infinite potential barrier, it is related to the more general problem of finding the resonance modes in a cavity. The problem is found to be separable for a biconvex-shaped cavity or quantum dot with an infinite potential barrier. This first shape of quantum dot corresponds to the intersection of two orthogonal confocal parabolas. Then plano-convex lens-shaped cavities or quantum dots are studied. This problem is no more separable in the parabolic coordinates but using symmetry properties, we show that the exact solutions of the problem are simple combinations of the previous solutions. The same approach is used for spherical coordinates and hemispherical quantum dots. It is finally shown that convex lens-shaped quantum dots give a good description of self-organized InAs quantum dots grown on InP

  3. Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source

    Directory of Open Access Journals (Sweden)

    A. Lunin

    2018-02-01

    Full Text Available Construction of the Linac Coherent Light Source II (LCLS-II is underway for the world’s first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw mode. The linac is segmented into four sections named as L0, L1, L2, and L3. Two 3.9 GHz cryomodules, each housing of eight third-harmonic cavities similar to the cavities developed for the European X-ray Free Electron Laser (XFEL, will be used in section L1 of the linac for linearizing the longitudinal beam profile. In this paper, we present a study of trapped high order modes (HOMs excited by a cw electron beam in the third-harmonic cavities of the LCLS-II linac. A detailed comparison of the original XFEL design and the LCLS-II design with a modified end group is performed in order to estimate the effect of a reduced beam pipe aperture on the efficiency of HOM damping. Furthermore, we apply a statistical analysis of the eigenmode spectrum for the estimation of the probability of resonant HOM losses and influence of HOMs on beam dynamics.

  4. Cavity-enhanced spectroscopies

    CERN Document Server

    van Zee, Roger

    2003-01-01

    ""Cavity-Enhanced Spectroscopy"" discusses the use of optical resonators and lasers to make sensitive spectroscopic measurements. This volume is written by the researcchers who pioneered these methods. The book reviews both the theory and practice behind these spectroscopic tools and discusses the scientific discoveries uncovered by these techniques. It begins with a chapter on the use of optical resonators for frequency stabilization of lasers, which is followed by in-depth chapters discussing cavity ring-down spectroscopy, frequency-modulated, cavity-enhanced spectroscopy, intracavity spectr

  5. Development of Control System for Fast Frequency Tuners of Superconducting Resonant Cavities for FLASH and XFEL Experiments

    CERN Document Server

    Przygoda, K

    2011-01-01

    This dissertation covers the recent research and development (R&D) activities of control systems for the fast frequency tuners of TESLA cavities and predicts the implications foreseen for large scale machines such as the FLASH and the planned XFEL. In particular, the framework of the presented activities is the effort toward the: 1. R&D of the driving circuit, 2. R&D of the control algorithm, 3. R&D of the control system. The main result of these activities is the permanent installation of the target piezo control system and its commissioning for 40 cavities divided into 5 accelerating modules at the DESY FLASH facility. The author’s contribution was the study of possible designs of high-voltage, high-current power amplifiers, used for driving the fast frequency tuners, shows that several parameters of such a device needs to be considered. The most important parameter is the input and output power estimation. This arises from the fact that the estimation is the most crucial issue for both po...

  6. Tumores malignos da cavidade nasal: tomografia computadorizada e ressonância magnética Malignant tumors of the nasal cavity: computed tomography and magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Ricardo Pires de Souza

    2004-10-01

    Full Text Available OBJETIVO: Este estudo propõe-se a avaliar o papel da tomografia computadorizada e da ressonância magnética na caracterização da extensão profunda dos tumores malignos da cavidade nasal. MATERIAIS E MÉTODOS: Entre 1990 e 2000 foram avaliados, retrospectivamente, 12 pacientes com diagnóstico de tumores malignos da cavidade nasal atendidos nos Departamentos de Diagnóstico por Imagem e Cirurgia de Cabeça e Pescoço do Complexo Hospitalar Heliópolis, São Paulo, SP. Todos os casos foram confirmados com exame anatomopatológico. RESULTADOS: Foi identificada extensão para os seios maxilares e etmoidal em seis pacientes, para a cavidade nasal contralateral, órbita e lâmina crivosa em cinco pacientes, para a nasofaringe e espaço mastigatório em dois pacientes, e para o seio cavernoso, fossas cranianas anterior e média, fossa pterigomaxilar, fissuras orbitárias superior e inferior, seio frontal, seio etmoidal contralateral, lâmina crivosa contralateral, palato duro e fossa pterigopalatina em um paciente. CONCLUSÃO: A análise precisa da extensão local e disseminação tumoral dada pela tomografia computadorizada e ressonância magnética desempenha papel importante no planejamento terapêutico, influenciando também o prognóstico.OBJECTIVE: The aim of this study is to evaluate the role of computed tomography and magnetic resonance imaging in the characterization of deep tissue extension of malignant tumors of the nasal cavity. MATERIALS AND METHODS: Twelve patients diagnosed with malignant tumors of the nasal cavity were retrospectively evaluated at the Departments of Diagnostic Imaging and Head and Neck Surgery of the "Complexo Hospitalar Heliópolis", São Paulo, Brazil, between 1990 and 2000. All cases were confirmed by histopathologic examination. RESULTS: Extension to the maxillary and ethmoid sinuses was identified in six patients, extension to contralateral nasal cavity, orbit and lamina cribosa in five patients, extension to

  7. Development of large grain cavities

    Directory of Open Access Journals (Sweden)

    W. Singer

    2013-01-01

    Full Text Available DESY activities on 1.3 GHz tesla shape single cell and nine-cell large grain (LG resonators are presented; results of the past five years are covered. The R&D program explores the potential for production of elliptical superconducting cavities. The main efforts have been devoted to material investigation, development of LG disk production, cavity fabrication from this material, and a search for appropriate treatment. More than 250 LG disks are manufactured; several single cell and 11 nine-cell resonators are produced and rf tested after buffered chemical polishing and after additional electropolishing. A maximum accelerating gradient of approximately 45  MV/m for this type of cavity was achieved in two resonators. Two of the LG cavities have been installed and are currently being used in the FLASH accelerator operation. Assembly of a cryomodule, consisting of LG cavities only, is in the works. Perspectives of the LG cavity application are discussed.

  8. Tailoring surface plasmon resonance and dipole cavity plasmon modes of scattering cross section spectra on the single solid-gold/gold-shell nanorod

    International Nuclear Information System (INIS)

    Chou Chau, Yuan-Fong; Lim, Chee Ming; Kumara, N. T. R. N.; Yoong, Voo Nyuk; Lee, Chuanyo; Huang, Hung Ji; Lin, Chun-Ting; Chiang, Hai-Pang

    2016-01-01

    Tunable surface plasmon resonance (SPR) and dipole cavity plasmon modes of the scattering cross section (SCS) spectra on the single solid-gold/gold-shell nanorod have been numerically investigated by using the finite element method. Various effects, such as the influence of SCS spectra under x- and y-polarizations on the surface of the single solid-gold/gold-shell nanorod, are discussed in detail. With the single gold-shell nanorod, one can independently tune the relative SCS spectrum width by controlling the rod length and rod diameter, and the surface scattering by varying the shell thickness and polarization direction, as well as the dipole peak energy. These behaviors are consistent with the properties of localized SPRs and offer a way to optically control and produce selected emission wavelengths from the single solid-gold/gold-shell nanorod. The electric field and magnetic distributions provide us a qualitative idea of the geometrical properties of the single solid-gold/gold-shell nanorod on plasmon resonance.

  9. 200-GHz and 50-GHz AWG channelized linewidth dependent transmission of weak-resonant-cavity FPLD injection-locked by spectrally sliced ASE.

    Science.gov (United States)

    Lin, Gong-Ru; Cheng, Tzu-Kang; Chi, Yu-Chieh; Lin, Gong-Cheng; Wang, Hai-Lin; Lin, Yi-Hong

    2009-09-28

    In a weak-resonant-cavity Fabry-Perot laser diode (WRC-FPLD) based DWDM-PON system with an array-waveguide-grating (AWG) channelized amplified spontaneous emission (ASE) source located at remote node, we study the effect of AWG filter bandwidth on the transmission performances of the 1.25-Gbit/s directly modulated WRC-FPLD transmitter under the AWG channelized ASE injection-locking. With AWG filters of two different channel spacings at 50 and 200 GHz, several characteristic parameters such as interfered reflection, relatively intensity noise, crosstalk reduction, side-mode-suppressing ratio and power penalty of BER effect of the WRC-FPLD transmitted data are compared. The 200-GHz AWG filtered ASE injection minimizes the noises of WRC-FPLD based ONU transmitter, improving the power penalty of upstream data by -1.6 dB at BER of 10(-12). In contrast, the 50-GHz AWG channelized ASE injection fails to promote better BER but increases the power penalty by + 1.5 dB under back-to-back transmission. A theoretical modeling elucidates that the BER degradation up to 4 orders of magnitude between two injection cases is mainly attributed to the reduction on ASE injection linewidth, since which concurrently degrades the signal-to-noise and extinction ratios of the transmitted data stream.

  10. Dental cavities

    Science.gov (United States)

    ... acids in plaque damage the enamel covering your teeth. It also creates holes in the tooth called cavities. Cavities usually do not hurt, unless they grow very large and affect nerves or cause a tooth fracture. An untreated cavity can lead to an infection ...

  11. Resonance

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2014-01-01

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

  12. Cavity-cavity conditional logic

    Science.gov (United States)

    Rosenblum, Serge; Gao, Yvonne Y.; Reinhold, Philip; Wang, Chen; Axline, Christopher; Frunzio, Luigi; Girvin, Steven M.; Jiang, Liang; Mirrahimi, Mazyar; Devoret, Michel H.; Schoelkopf, Robert J.

    In a superconducting circuit architecture, the highest coherence times are typically offered by 3D cavities. Moreover, these cavities offer a hardware-efficient way of redundantly encoding quantum information. While single-qubit control on a cavity has already been demonstrated, there is a need for a universal two-qubit gate between such cavities. In this talk, we demonstrate a cavity-cavity gate by parametric pumping on a fixed-frequency transmon interacting with the two cavities. Every gate application lowers the state fidelity by only 1%, while maintaining an entangling rate on-off ratio of 29dB. Additionally, we show that the gate is applicable not only to qubits consisting of single photons, but also to more complex encodings. These results illustrate the usefulness of cavities beyond the mere storage of quantum information, and pave the way towards gates between error-corrected logical qubits.

  13. Regenerative feedback resonant circuit

    Science.gov (United States)

    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.

  14. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...... of the book: how connotations of past meanings may resonate through time, in new contexts, assuming new meanings without surrendering the old....

  15. Cavity types

    CERN Document Server

    Gerigk, Frank

    2011-01-01

    In the field of particle accelerators the most common use of RF cavities is to increase the particle velocity of traversing particles. This feature makes them one of the core ingredients of every accelerator, and in the case of linear accelerators they are even the dominant machine component. Since there are many different types of accelerator, RF cavities have been optimized for different purposes and with different abilities, e.g., cavities with fixed or variable RF frequency, cavities for short or long pulses/CW operation, superconducting and normal-conducting cavities. This lecture starts with a brief historical introduction and an explanation on how to get from Maxwell's equations to a simple cavity. Then, cavities will be classified by the type of mode that is employed for acceleration, and an explanation is given as to why certain modes are used in particular cavity types. The lecture will close with a comparison of normal versus superconducting cavities and a few words on the actual power consumption ...

  16. RESONANCE

    Indian Academy of Sciences (India)

    maceutical, paper, food, dyes, petrochemi- cals, pigments, etc., to identify molecules, to monitor reaction products and so on. One of the most spectacular contributions of NMR has been in the development of magnetic resonance imaging (MRI), a method that has today revolutionized diagnosis and treatment of diseases in ...

  17. accelerating cavity

    CERN Multimedia

    On the inside of the cavity there is a layer of niobium. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment.

  18. radiofrequency cavity

    CERN Multimedia

    1988-01-01

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  19. Mechanical Properties of Niobium Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Dhakal, Pashupati [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Matalevich, Joseph R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Myneni, Ganapati Rao [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    The mechanical stability of bulk Nb cavity is an important aspect to be considered in relation to cavity material, geometry and treatments. Mechanical properties of Nb are typically obtained from uniaxial tensile tests of small samples. In this contribution we report the results of measurements of the resonant frequency and local strain along the contour of single-cell cavities made of ingot and fine-grain Nb of different purity subjected to increasing uniform differential pressure, up to 6 atm. Measurements have been done on cavities subjected to different heat treatments. Good agreement between finite element analysis simulations and experimental data in the elastic regime was obtained with a single set of values of Young’s modulus and Poisson’s ratio. The experimental results indicate that the yield strength of medium-purity ingot Nb cavities is higher than that of fine-grain, high-purity Nb.

  20. Upgraded cavities for the positron accumulator ring of the APS

    International Nuclear Information System (INIS)

    Kang, Y.W.; Jiang, X.; Mangra, D.

    1997-01-01

    Upgraded versions of cavities for the APS positron accumulator ring (PAR) have been built and are being tested. Two cavities are in the PAR: a fundamental 9.8-MHz cavity and a twelfth harmonic 117.3-MHz cavity. Both cavities have been manufactured for higher voltage operation with improved Q-factors, reliability, and tuning capability. Both cavities employ current-controlled ferrite tuners for control of the resonant frequency. The harmonic cavity can be operated in either a pulsed mode or a CW mode. The rf properties of the cavities are presented

  1. Additive Manufactured Superconducting Cavities

    Science.gov (United States)

    Holland, Eric; Rosen, Yaniv; Woolleet, Nathan; Materise, Nicholas; Voisin, Thomas; Wang, Morris; Mireles, Jorge; Carosi, Gianpaolo; Dubois, Jonathan

    Superconducting radio frequency cavities provide an ultra-low dissipative environment, which has enabled fundamental investigations in quantum mechanics, materials properties, and the search for new particles in and beyond the standard model. However, resonator designs are constrained by limitations in conventional machining techniques. For example, current through a seam is a limiting factor in performance for many waveguide cavities. Development of highly reproducible methods for metallic parts through additive manufacturing, referred to colloquially as 3D printing\\x9D, opens the possibility for novel cavity designs which cannot be implemented through conventional methods. We present preliminary investigations of superconducting cavities made through a selective laser melting process, which compacts a granular powder via a high-power laser according to a digitally defined geometry. Initial work suggests that assuming a loss model and numerically optimizing a geometry to minimize dissipation results in modest improvements in device performance. Furthermore, a subset of titanium alloys, particularly, a titanium, aluminum, vanadium alloy (Ti - 6Al - 4V) exhibits properties indicative of a high kinetic inductance material. This work is supported by LDRD 16-SI-004.

  2. Droplet based cavities and lasers

    DEFF Research Database (Denmark)

    Mølhave, Kristian; Kristensen, Anders; Mortensen, Asger

    2009-01-01

    The self-organized and molecularly smooth surface on liquid microdroplets makes them attractive as optical cavities with very high quality factors. This chapter describes the basic theory of optical modes in spherical droplets. The mechanical properties including vibrational excitation are also...... described, and their implications for microdroplet resonator technology are discussed. Optofluidic implementations of microdroplet resonators are reviewed with emphasis on the basic optomechanical properties....

  3. Pathways for the direct extension of malignant pleural mesothelioma into peritoneal cavity. Assessment using computed tomography (CT) and magnetic resonance imaging (MRI)

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Takashi; Inoue, Yasushi; Iida, Shinichiro; Tonomura, Atsushi; Miyake, Mitsutomi; Togawa, Naoki; Hada, Toshikazu [Hyogo Coll. of Medicine, Nishinomiya (Japan); Chahinian, A.P.

    2000-01-01

    We investigated pathways for the direct extension of malignant pleural mesothelioma into peritoneal cavity using CT and MRI, and compared the radiographic findings with the corresponding gross pathologic features at thoracotomy or autopsy to make sure an accurate radiologic assessment. Three different pathways could be recognized ; direct invasion of diaphragmatic muscle to penetrate into peritoneal cavity, direct contiguous extension along the descending aorta into retroperitoneum through the aortic hiatus, and extension from the medial and lateral arcuate ligaments into retroperitoneum along the psoas major muscle and quadratus lumbrum muscle. MRI could evaluate a diaphragmatic muscle invasion and differentiate it from transdiaphragmatic extension. Irregularity of the infradiaphragmatic fat tissue in T1-weighted image was a reliable indicator of transdiaphragmatic extension. MRI is of value in assessing diaphragmatic involvement in patients with malignant pleural mesothelioma. (author)

  4. Temperature stabilization of optofluidic photonic crystal cavities

    DEFF Research Database (Denmark)

    Kamutsch, Christian; Smith, Cameron L.C.; Graham, Alexandra

    2009-01-01

    demonstrate a PhC cavity with a quality factor of Q15 000 that exhibits a temperature-independent resonance. Temperature-stable cavities constitute a major building block in the development of a large suite of applications from high-sensitivity sensor systems for chemical and biomedical applications...

  5. Cavity Optomechanics

    OpenAIRE

    Kippenberg, T. J.; Vahala, K. J.

    2007-01-01

    The coupling of mechanical and optical degrees of freedom via radiation pressure has been a subject of early research in the context of gravitational wave detection. Recent experimental advances have allowed studying for the first time the modifications of mechanical dynamics provided by radiation pressure. This paper reviews the consequences of back-action of light confined in whispering-gallery dielectric micro-cavities, and presents a unified treatment of its two manifestations: notably th...

  6. Mechanical design and fabrication of power feed cavity test setup

    International Nuclear Information System (INIS)

    Ghodke, S.R.; Dhavle, A.S.; Sharma, Vijay; Sarkar, Shreya; Kumar, Mahendra; Nayak, Susanta; Barnwal, Rajesh; Jayaprakash, D.; Mondal, J.; Nimje, V.T.; Mittal, K.C.; Gantayet, L.M.

    2013-01-01

    Power feed cavity set up consists of nine number of accelerating cavity and eight numbers of coupling cavity for testing of power feed cavity with coupling flange for 2856 MHz S band standing wave coupled cavity linac. When we are assembling the cavity and applying the pressure, its resonance frequency changes with applied pressure/load. After some critical pressure/load frequency change becomes negligible or zero. This set up will be used to find out assembly performance of power feed cavity and its coupler. Top four cavity or eight half cells as well as bottom four cavity or eight half cells will be brazed separately. Power feed cavity will be sandwiched between this two brazed cavity assemblies. This paper discuss about linear motion bush, linear motion rod, load cell, hydraulic actuator, power pack, stepper motor PLC control, jig boring, alignment, tolerances and assembly procedure for this test setup. (author)

  7. STRUCTURAL ANALYSIS OF SUPERCONDUCTING ACCELERATOR CAVITIES

    International Nuclear Information System (INIS)

    Schrage, D.

    2000-01-01

    The static and dynamic structural behavior of superconducting cavities for various projects was determined by finite element structural analysis. The β = 0.61 cavity shape for the Neutron Science Project was studied in detail and found to meet all design requirements if fabricated from five millimeter thick material with a single annular stiffener. This 600 MHz cavity will have a Lorentz coefficient of minus1.8 Hz/(Mv/meter) 2 and a lowest structural resonance of more than 100 Hz. Cavities at β = 0.48, 0.61, and 0.77 were analyzed for a Neutron Science Project concept which would incorporate 7-cell cavities. The medium and high beta cavities were found to meet all criteria but it was not possible to generate a β = 0.48 cavity with a Lorentz coefficient of less than minus3 Hz/(Mv/meter) 2

  8. Finite-Difference Time-Domain Integration of Ultrafast Dynamics in Optical Resonators

    National Research Council Canada - National Science Library

    Basinger, Scott

    1993-01-01

    .... The resonator is a Fabry-Perot cavity that has a nonlinear absorbing material in the center. When an optical field of the resonant frequency is incident upon the cavity, the field intensity increases inside the cavity...

  9. Mechanical Properties of Ingot Nb Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi; Dhakal, Pashupati; Kneisel, Peter; Mammosser, John; Matalevich, Joseph; Rao Myneni, Ganapati

    2014-07-01

    This contribution presents the results of measurements of the resonant frequency and of strain along the contour of a single-cell cavity made of ingot Nb subjected to increasing uniform differential pressure, up to 6 atm. The data were used to infer mechanical properties of this material after cavity fabrication, by comparison with the results from simulation calculations done with ANSYS. The objective is to provide useful information about the mechanical properties of ingot Nb cavities which can be used in the design phase of SRF cavities intended to be built with this material.

  10. Circuit QED with 3D cavities

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

    In typical circuit QED systems on-chip superconducting qubits are coupled to integrated coplanar microwave resonators. Due to the planar geometry, the resonators are often a limiting factor regarding the total coherence of the system. Alternatively, similar hybrid systems can be realized using 3D microwave cavities. Here, we present design considerations for the 3D microwave cavity as well as the superconducting transmon qubit. Moreover, we show experimental data of a high purity aluminum cavity demonstrating quality factors above 1.4 .10{sup 6} at the single photon level and a temperature of 50 mK. Our experiments also demonstrate that the quality factor is less dependent on the power compared to planar resonator geometries. Furthermore, we present strategies for tuning both the cavity and the qubit individually.

  11. Optical single photons on-demand teleported from microwave cavities

    Science.gov (United States)

    Barzanjeh, Sh; Vitali, D.; Tombesi, P.

    2013-03-01

    We propose a scheme for entangling the optical and microwave output modes of the respective cavities by using a micro mechanical resonator. The micro mechanical resonator, on one side, is capacitively coupled to the microwave cavity and, on the other side, it is coupled to a high-finesses optical cavity. We then show how this continuous variable entanglement can be profitably used to teleport the non-Gaussian number state |1> and the superposition (|0\\rangle +|1\\rangle )/\\sqrt 2 from the microwave cavity output mode onto an output of the optical cavity mode with fidelity much larger than the no-cloning limit.

  12. Off-resonance R1ρ relaxation outside of the fast exchange limit: An experimental study of a cavity mutant of T4 lysozyme

    International Nuclear Information System (INIS)

    Korzhnev, Dmitry M.; Orekhov, Vladislav Yu.; Dahlquist, Frederick W.; Kay, Lewis E.

    2003-01-01

    An 15 N off-resonance R 1ρ spin relaxation study of an L99A point mutant of T4 lysozyme is presented. Previous CPMG-based relaxation dispersion studies of exchange in this protein have established that the molecule interconverts between a populated ground state and an excited state (3.4%) with an exchange rate constant of 1450 s -1 at 25 deg. C. It is shown that for the majority of residues in this protein the offset dependence of the R 1ρ relaxation rates cannot be well fit using models which are only valid in the fast exchange regime. In contrast, a recently derived expression by Trott and Palmer (J. Magn. Reson., 154, 157-160, 2002) which is valid over a wider window of exchange than other relations, is shown to fit the data well. Values of (signed) chemical shift differences between exchanging sites have been extracted and are in reasonable agreement with shift differences measured using CPMG methods. A set of simulations is presented which help establish the exchange regimes that are best suited to analysis by off-resonance R 1ρ techniques

  13. A split-cavity design for the incorporation of a DC bias in a 3D microwave cavity

    NARCIS (Netherlands)

    Cohen, M.A.; Yuan, M.; de Jong, B.W.A.; Beukers, Ewout; Bosman, S.J.; Steele, G.A.

    2017-01-01

    We report on a technique for applying a DC bias in a 3D microwave cavity. We achieve this by isolating the two halves of the cavity with a dielectric and directly using them as DC electrodes. As a proof of concept, we embed a variable capacitance diode in the cavity and tune the resonant

  14. Investigation on computation of elliptical microwave plasma cavity

    Science.gov (United States)

    Liao, Xiaoli; Liu, Hua; Zhang, Kai

    2008-12-01

    In recent years, the advance of the elliptical resonant cavity and focus cavity is known by many people. There are homogeneous and multipatternal virtues in the focus dimensional microwave field of the elliptical resonant cavity. It is very suitable for applying the low power microwave biological effect equipment. However, when designing the elliptical resonant cavity may meet the problems of complex and huge computation need to be solved. This paper proposed the simple way of approximate processing the Mathieu function. It can greatly simplify the difficulty and decrease the scale of computation. This method can satisfy the requirements of research and development within project permitted precision.

  15. Call for Papers: Cavity QED

    Science.gov (United States)

    Lange, W.; Gerard, J.-M.

    2003-06-01

    Cavity QED interactions of light and matter have been investigated in a wide range of systems covering the spectrum from microwaves to optical frequencies, using media as diverse as single atoms and semiconductors. Impressive progress has been achieved technologically as well as conceptually. This topical issue of Journal of Optics B: Quantum and Semiclassical Optics is intended to provide a comprehensive account of the current state of the art of cavity QED by uniting contributions from researchers active across this field. As Guest Editors of this topical issue, we invite manuscripts on current theoretical and experimental work on any aspects of cavity QED. The topics to be covered will include, but are not limited to: bulletCavity QED in optical microcavities bulletSemiconductor cavity QED bulletQuantum dot cavity QED bulletRydberg atoms in microwave cavities bulletPhotonic crystal cavity QED bulletMicrosphere resonators bulletMicrolasers and micromasers bulletMicrodroplets bulletDielectric cavity QED bulletCavity QED-based quantum information processing bulletQuantum state engineering in cavities The DEADLINE for submission of contributions is 31 July 2003 to allow the topical issue to appear in about February 2004. All papers will be peer-reviewed in accordance with the normal refereeing procedures and standards of Journal of Optics B: Quantum and Semiclassical Optics. Advice on publishing your work in the journal may be found at www.iop.org/journals/authors/jopb. Submissions should ideally be in either standard LaTeX form or Microsoft Word. There are no page charges for publication. In addition to the usual 50 free reprints, the corresponding author of each paper published will receive a complimentary copy of the topical issue. Contributions to the topical issue should if possible be submitted electronically at www.iop.org/journals/jopb. or by e-mail to jopb@iop.org. Authors unable to submit online or by e-mail may send hard copy contributions (enclosing the

  16. Calculation of the resonance frequency change for a cavity charged by a plasma with or without a static magnetic field; Calcul du glissement de la frequence de resonance d'une cavite chargee par un plasma en presence ou non d'un champ magnetique statique

    Energy Technology Data Exchange (ETDEWEB)

    Melin, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Service de physique appliquee, service d' ionique generale, section d' etude des interractions onde-plasma

    1967-03-01

    In the mere case of a cold plasma with or without static magnetic field, are given two methods of calculation of resonance frequency shift and absorption in a cylindrical cavity crossed by a plasma column: 1. A perturbation method, already known and used for electronic density measurements is restated and its application is used for several high frequency cavity modes. 2. An exact method employing Maxwell's equations, which however necessitates a computer, is compared with the first one; it permits a determination of the validity limits of the perturbation method and to draw conclusions,. [French] On donne Dans le cas d'un plasma froid en presence ou non de champ magnetique statique deux methodes de calcul de la derive de frequence de resonance et de l'absorption dans une cavite cylindrique traversee par une colonne de plasma: 1. Une methode de perturbation deja connue et employee dans les mesures de densite eleetronique; on en rappelle le principe et on en fait l'application pour plusieurs modes de la cavite haute frequence. 2. Une methode rigoureuse a partir des equations de Maxwell, dont la resolution necessite l'emploi d'un ordinateur; cette methode comparee a la precedente permet d'en determiner les limites de validite et de tirer des conclusions. (auteur)

  17. Unstable resonator with multiple outputs

    Science.gov (United States)

    Konopnicki, M. J.; Smithers, M. E.

    1983-03-01

    Two or more unstable optical resonators can be coupled together by sharing optical elements. The result is then a single compound resonator with multiple outputs. For identical coupled cavities, the transverse structure of the outputs would be identical. In general, there will be misalignments and other aberrations that will vary from cavity to cavity. The cumulative effects of such aberrations are treated using both analytical and numerical approaches. It is shown that the average output of a multioutput resonator is the same as the output of a single uncoupled resonator with aberrations equal to the average of those contained in the multioutput resonator.

  18. Superconducting cavity driving with FPGA controller

    Energy Technology Data Exchange (ETDEWEB)

    Czarski, T.; Koprek, W.; Pozniak, K.T.; Romaniuk, R.S. [Warsaw Univ. of Technology (Poland); Simrock, S.; Brand, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Chase, B.; Carcagno, R.; Cancelo, G. [Fermi National Accelerator Lab., Batavia, IL (United States); Koeth, T.W. [Rutgers - the State Univ. of New Jersey, NJ (United States)

    2006-07-01

    The digital control of several superconducting cavities for a linear accelerator is presented. The laboratory setup of the CHECHIA cavity and ACC1 module of the VU-FEL TTF in DESY-Hamburg have both been driven by a Field Programmable Gate Array (FPGA) based system. Additionally, a single 9-cell TESLA Superconducting cavity of the FNPL Photo Injector at FERMILAB has been remotely controlled from WUT-ISE laboratory with the support of the DESY team using the same FPGA control system. These experiments focused attention on the general recognition of the cavity features and projected control methods. An electrical model of the resonator was taken as a starting point. Calibration of the signal path is considered key in preparation for the efficient driving of a cavity. Identification of the resonator parameters has been proven to be a successful approach in achieving required performance; i.e. driving on resonance during filling and field stabilization during flattop time while requiring reasonable levels of power consumption. Feed-forward and feedback modes were successfully applied in operating the cavities. Representative results of the experiments are presented for different levels of the cavity field gradient. (orig.)

  19. Multi-detector row computed tomography (MDCT and magnetic resonance imaging (MRI in the evaluation of the mandibular invasion by squamous cell carcinomas (SCC of the oral cavity. Correlation with pathological data

    Directory of Open Access Journals (Sweden)

    Di Giovanni Salvatore

    2010-06-01

    Full Text Available Abstract Background To retrospectively compare the diagnostic accuracy of magnetic resonance imaging (MRI and multidetector-row computed tomography (MDCT in the assessment of the mandibular invasion by squamous cell carcinoma (SCC having histopathological exams as standard of reference. Materials and methods Institutional review board approval with a waiver of informed patient consent was obtained. Of the 147 patients selected from our database who underwent surgical excision of a tumour arising into the oral cavity, thirty-six patients (26 men, 10 women; mean age, 56 years; range, 30-75 years with hystologically proven SCC who performed both a preoperative MRI and MDCT, composed our final study population. Images were qualitatively analyzed in consensus by two expert radiologist in head and neck imaging. Sensitivity, specificity, accuracy, positive predictive value (PPV and negative predictive value (NPV were assessed for both MRI and MDCT. Differences in sensitivity, specificity, positive and negative predictive values were calculated at a statistical significance of p Results The sensitivity, the specificity and the accuracy of MRI and MDCT in the detection of the mandibular involvement were respectively 93%, 82%, 86% and 79%, 82%, 81%, while the positive predictive value (PPV and negative predictive value (NPV were respectively 76%, 95% and 73%, 86%. There wasn't any statistically significant difference in overall diagnostic accuracy between MRI and MDCT in the evaluation of mandibular tumour invasion (p > .05. Conclusion MRI showed to have a higher sensitivity compare to MDCT in the assessment of mandibular involvement from SCC arising in the oral cavity although none statistically significant differences were noted.

  20. A micropillar for cavity optomechanics

    Science.gov (United States)

    Kuhn, Aurélien; Neuhaus, Leonhard; Van Brackel, Emmanuel; Chartier, Claude; Ducloux, Olivier; Le Traon, Olivier; Michel, Christophe; Pinard, Laurent; Flaminio, Raffaele; Deléglise, Samuel; Briant, Tristan; Cohadon, Pierre-François; Heidmann, Antoine

    2014-12-01

    Demonstrating the quantum ground state of a macroscopic mechanical object is a major experimental challenge in physics, at the origin of the rapid emergence of cavity optomechanics. We have developed a new generation of optomechanical devices, based on a microgram quartz micropillar with a very high mechanical quality factor. The structure is used as end mirror in a Fabry-Perot cavity with a high optical finesse, leading to ultra-sensitive interferometric measurement of the resonator displacement. We expect to reach the ground state of this optomechanical resonator by combining cryogenic cooling in a dilution fridge at 30 mK and radiation-pressure cooling. We have already carried out a quantum-limited measurement of the micropillar thermal noise at low temperature.

  1. Resonant MEMS tunable VCSEL

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Chung, Il-Sug; Semenova, Elizaveta

    2013-01-01

    We demonstrate how resonant excitation of a microelectro-mechanical system can be used to increase the tuning range of a vertical-cavity surface-emitting laser two-fold by enabling both blue- and red-shifting of the wavelength. In this way a short-cavity design enabling wide tuning range can be r...

  2. Radiation-pressure-mediated control of an optomechanical cavity

    Science.gov (United States)

    Cripe, Jonathan; Aggarwal, Nancy; Singh, Robinjeet; Lanza, Robert; Libson, Adam; Yap, Min Jet; Cole, Garrett D.; McClelland, David E.; Mavalvala, Nergis; Corbitt, Thomas

    2018-01-01

    We describe and demonstrate a method to control a detuned movable-mirror Fabry-Pérot cavity using radiation pressure in the presence of a strong optical spring. At frequencies below the optical spring resonance, self-locking of the cavity is achieved intrinsically by the optomechanical (OM) interaction between the cavity field and the movable end mirror. The OM interaction results in a high rigidity and reduced susceptibility of the mirror to external forces. However, due to a finite delay time in the cavity, this enhanced rigidity is accompanied by an antidamping force, which destabilizes the cavity. The cavity is stabilized by applying external feedback in a frequency band around the optical spring resonance. The error signal is sensed in the amplitude quadrature of the transmitted beam with a photodetector. An amplitude modulator in the input path to the cavity modulates the light intensity to provide the stabilizing radiation pressure force.

  3. Different optical properties in different periodic slot cavity geometrical morphologies

    Science.gov (United States)

    Zhou, Jing; Shen, Meng; Du, Lan; Deng, Caisong; Ni, Haibin; Wang, Ming

    2016-09-01

    In this paper, optical properties of two-dimensional periodic annular slot cavity arrays in hexagonal close-packing on a silica substrate are theoretically characterized by finite difference time domain (FDTD) simulation method. By simulating reflectance spectra, electric field distribution, and charge distribution, we confirm that multiple cylindrical surface plasmon resonances can be excited in annular inclined slot cavities by linearly polarized light, in which the four reflectance dips are attributed to Fabry-Perot cavity resonances in the coaxial cavity. A coaxial waveguide mode TE11 will exist in these annular cavities, and the wavelengths of these reflectance dips are effectively tailored by changing the geometrical pattern of slot cavity and the dielectric materials filled in the cavities. These resonant wavelengths are localized in annular cavities with large electric field enhancement and dissipate gradually due to metal loss. The formation of an absorption peak can be explained from the aspect of phase matching conditions. We observed that the proposed structure can be tuned over the broad spectral range of 600-4000 nm by changing the outer and inner radii of the annular gaps, gap surface topography. Meanwhile, different lengths of the cavity may cause the shift of resonance dips. Also, we study the field enhancement at different vertical locations of the slit. In addition, dielectric materials filling in the annular gaps will result in a shift of the resonance wavelengths, which make the annular cavities good candidates for refractive index sensors. The refractive index sensitivity of annular cavities can also be tuned by the geometry size and the media around the cavity. Annular cavities with novel applications can be implied as surface enhanced Raman spectra substrates, refractive index sensors, nano-lasers, and optical trappers. Project supported by the National Natural Science Foundation of China (Grant No. 61178044), the Natural Science Foundation

  4. Nylon Sleeve for Cavity Amplifier Holds Tuning Despite Heat

    Science.gov (United States)

    Derr, Lloyd

    1964-01-01

    The problem: Detuning of cavity amplifiers with change in temperature. This results in deterioration of the performance of the amplifier at its design frequency. In cavity amplifiers and filters it is desirable that constant performance be maintained regardless of thermal changes. These changes often cause an "off resonance shift" in a cavity filter and a deterioration of performance in a cavity amplifier. The solution: Mount the tuning probe in a nylon sleeve. Thermal expansion and contraction of the nylon nullifies unwanted capacitive and inductive changes in the resonant elements.

  5. Interaction of IREB with a cavity

    International Nuclear Information System (INIS)

    Sawhney, R.; Mishra, Mamta; Purkayastha, A.D.; Rambabu, P.; Maheshwari, K.P.

    1991-01-01

    The propagation of an intense pulsed relativistic electron beam (IREB) through a cavity resonator is considered. The cavity gets shock excited. The electromagnetic fields so generated interact with the beam in such a way that the energy is transferred from the front of the beam to the back. As a result the beams gets energized but shortened in time. Analysis for the chosen dominant mode of the cavity viz. TMsub(010) is carried out. The induced electric field excited is calculated and the accelerating potential is estimated. The results are compared with the recent-experiments. (author). 5 refs., 1 fig

  6. Analysis of dual coupler nested coupled cavities.

    Science.gov (United States)

    Adib, George A; Sabry, Yasser M; Khalil, Diaa

    2017-12-01

    Coupled ring resonators are now forming the basic building blocks in several optical systems serving different applications. In many of these applications, a small full width at half maximum is required, along with a large free spectral range. In this work, a configuration of passive coupled cavities constituting dual coupler nested cavities is proposed. A theoretical study of the configuration is presented allowing us to obtain analytical expressions of its different spectral characteristics. The transfer function of the configuration is also used to generate design curves while comparing these results with analytical expressions. Finally, the configuration is compared with other coupled cavity configurations.

  7. Segmented trapped vortex cavity

    Science.gov (United States)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  8. Seismic wave interaction with underground cavities

    Science.gov (United States)

    Schneider, Felix M.; Esterhazy, Sofi; Perugia, Ilaria; Bokelmann, Götz

    2016-04-01

    Realization of the future Comprehensive Nuclear Test Ban Treaty (CTBT) will require ensuring its compliance, making the CTBT a prime example of forensic seismology. Following indications of a nuclear explosion obtained on the basis of the (IMS) monitoring network further evidence needs to be sought at the location of the suspicious event. For such an On-Site Inspection (OSI) at a possible nuclear test site the treaty lists several techniques that can be carried out by the inspection team, including aftershock monitoring and the conduction of active seismic surveys. While those techniques are already well established, a third group of methods labeled as "resonance seismometry" is less well defined and needs further elaboration. A prime structural target that is expected to be present as a remnant of an underground nuclear explosion is a cavity at the location and depth the bomb was fired. Originally "resonance seismometry" referred to resonant seismic emission of the cavity within the medium that could be stimulated by an incident seismic wave of the right frequency and observed as peaks in the spectrum of seismic stations in the vicinity of the cavity. However, it is not yet clear which are the conditions for which resonant emissions of the cavity could be observed. In order to define distance-, frequency- and amplitude ranges at which resonant emissions could be observed we study the interaction of seismic waves with underground cavities. As a generic model for possible resonances we use a spherical acoustic cavity in an elastic full-space. To solve the forward problem for the full elastic wave field around acoustic spherical inclusions, we implemented an analytical solution (Korneev, 1993). This yields the possibility of generating scattering cross-sections, amplitude spectrums and synthetic seismograms for plane incident waves. Here, we focus on the questions whether or not we can expect resonant responses in the wave field scattered from the cavity. We show

  9. Quantum noise interference and backaction cooling in cavity nanomechanics.

    Science.gov (United States)

    Elste, Florian; Girvin, S M; Clerk, A A

    2009-05-22

    We present a theoretical analysis of a novel cavity electromechanical system where a mechanical resonator directly modulates the damping rate kappa of a driven electromagnetic cavity. We show that via a destructive interference of quantum noise, the driven cavity can effectively act like a zero-temperature bath irrespective of the ratio kappa/omega_{M}, where omega_{M} is the mechanical frequency. This scheme thus allows one to cool the mechanical resonator to its ground state without requiring the cavity to be in the so-called good cavity limit kappa < omega_{M}. The system described here could be implemented directly using setups similar to those used in recent experiments in cavity electromechanics.

  10. TM01 mode accelerating cavity optimization

    International Nuclear Information System (INIS)

    Manca, J.J.; Knapp, E.A.

    1978-08-01

    The cost of an accelerator depends greatly upon the effective use of rf power for particle acceleration. Before completing an accelerator design, an optimization of the accelerating cells relative to the effective shunt impedance should be made to measure the structure's efficiency in providing a high and effective acceleration of particles for a given rf power. Optimization of the accelerating cell resonant at f/sub r/ = 1350 MHz (TM 01 mode) relative to the maximum effective shunt impedance ZT 2 was performed at the Los Alamos Scientific Laboratory using the computer program SUPERFISH. The study was parametric; one parameter was changed while the others were held constant. Frequency adjustments were made by changing the cavity radius. Results presented in this report can be used to design similar cavities at different resonant frequencies or to design a more complicated cavity (TM 02 mode) for the disk and washer structure

  11. Circuit QED with 3D cavities

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Edwar; Eder, Peter; Fischer, Michael; Goetz, Jan; Deppe, Frank; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, TU Muenchen, 85748 Garching (Germany); Nanosystems Initiative Munich (NIM), 80799 Muenchen (Germany); Haeberlein, Max; Wulschner, Karl Friedrich [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, TU Muenchen, 85748 Garching (Germany); Fedorov, Kirill; Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany)

    2016-07-01

    In typical circuit QED systems, on-chip superconducting qubits are coupled to integrated coplanar microwave resonators. Due to the planar geometry, the resonators are often a limiting factor regarding the total coherence of the system. Alternatively, similar hybrid systems can be realized using 3D microwave cavities. Here, we present studies on transmon qubits capacitively coupled to 3D cavities. The internal quality factors of our 3D cavities, machined out of high purity aluminum, are above 1.4 .10{sup 6} at the single photon level and a temperature of 50 mK. For characterization of the sample, we perform dispersive shift measurements up to the third energy level of the qubit. We show simulations and data describing the effect of the transmon geometry on it's capacitive properties. In addition, we present progress towards an integrated quantum memory application.

  12. Minimum wakefield achievable by waveguide damped cavity

    International Nuclear Information System (INIS)

    Lin, X.E.; Kroll, N.M.

    1995-01-01

    The authors use an equivalent circuit to model a waveguide damped cavity. Both exponentially damped and persistent (decay t -3/2 ) components of the wakefield are derived from this model. The result shows that for a cavity with resonant frequency a fixed interval above waveguide cutoff, the persistent wakefield amplitude is inversely proportional to the external Q value of the damped mode. The competition of the two terms results in an optimal Q value, which gives a minimum wakefield as a function of the distance behind the source particle. The minimum wakefield increases when the resonant frequency approaches the waveguide cutoff. The results agree very well with computer simulation on a real cavity-waveguide system

  13. All-optical tunable photonic crystal cavity

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    We demonstrate an ultra-small photonic crystal cavity with two resonant modes. An all-optical tuning operation based on the free-carrier plasma effect is, for the first time, realized utilizing a continuous wave light source. The termo-optical effect is minimized by isoproponal infiltration...

  14. Toward more accurate loss tangent measurements in reentrant cavities

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, R. D.

    1980-05-01

    Karpova has described an absolute method for measurement of dielectric properties of a solid in a coaxial reentrant cavity. His cavity resonance equation yields very accurate results for dielectric constants. However, he presented only approximate expressions for the loss tangent. This report presents more exact expressions for that quantity and summarizes some experimental results.

  15. RF cavity using liquid dielectric for tuning and cooling

    Science.gov (United States)

    Popovic, Milorad [Warrenville, IL; Johnson, Rolland P [Newport News, VA

    2012-04-17

    A system for accelerating particles includes an RF cavity that contains a ferrite core and a liquid dielectric. Characteristics of the ferrite core and the liquid dielectric, among other factors, determine the resonant frequency of the RF cavity. The liquid dielectric is circulated to cool the ferrite core during the operation of the system.

  16. Cavity squeezing by a quantum conductor

    International Nuclear Information System (INIS)

    Mendes, Udson C; Mora, Christophe

    2015-01-01

    Hybrid architectures integrating mesoscopic electronic conductors with resonant microwave cavities have a great potential for investigating unexplored regimes of electron–photon coupling. In this context, producing nonclassical squeezed light is a key step towards quantum communication with scalable solid-state devices. Here we show that parametric driving of the electronic conductor induces a squeezed steady state in the cavity. We find that squeezing properties of the cavity are essentially determined by the electronic noise correlators of the quantum conductor. In the case of a tunnel junction, we predict that squeezing is optimized by applying a time-periodic series of quantized δ—peaks in the bias voltage. For an asymmetric quantum dot, we show that a sharp Leviton pulse is able to achieve perfect cavity squeezing. (paper)

  17. Rigorous analysis of trapped modes in accelerating cavities

    Directory of Open Access Journals (Sweden)

    Rolf Schuhmann

    2000-12-01

    Full Text Available We report the development of different algorithms for the calculation of quality factors of eigenmodes in accelerating cavities, which have resonance frequencies above the cutoff frequency of the beam tubes. The analysis is based on a discretization of such cavity structures by the finite integration technique, and the radiation at the open boundaries is systematically taken into account by different approaches in time and frequency domain. Results indicate that even single cell cavities of the TESLA type show Q values of 10^{3} and multicell cavities values in excess of 10^{4}. Thus these modes may cause considerable beam instabilities. Comparison with the conventional method of analyzing closed cavities and identifying modes with little change in frequency as a function of boundary condition shows qualitative differences. Some modes from the closed cavity model do not exist in the open structure and thus would be misinterpreted as trapped modes when only a closed cavity analysis is employed.

  18. Open waveguide cavity using a negative index medium.

    Science.gov (United States)

    Yan, Wei; Shen, Linfang

    2008-12-01

    An open waveguide cavity formed by a pair of planar waveguides, in which one guiding layer is a negative index medium and the other is a positive index medium, is theoretically demonstrated. For such a waveguide cavity the resonant frequency is independent of the total length of the waveguide system. With the coupled mode theory it is shown that energy flow circulation can be established through the special coupling between the waveguides at the resonant frequency, and thus the wave fields are localized. This phenomenon is further verified numerically with the finite-difference time-domain method. The quality factor of the open waveguide cavity is also discussed.

  19. Cavity Optomechanics at Millikelvin Temperatures

    Science.gov (United States)

    Meenehan, Sean Michael

    The field of cavity optomechanics, which concerns the coupling of a mechanical object's motion to the electromagnetic field of a high finesse cavity, allows for exquisitely sensitive measurements of mechanical motion, from large-scale gravitational wave detection to microscale accelerometers. Moreover, it provides a potential means to control and engineer the state of a macroscopic mechanical object at the quantum level, provided one can realize sufficiently strong interaction strengths relative to the ambient thermal noise. Recent experiments utilizing the optomechanical interaction to cool mechanical resonators to their motional quantum ground state allow for a variety of quantum engineering applications, including preparation of non-classical mechanical states and coherent optical to microwave conversion. Optomechanical crystals (OMCs), in which bandgaps for both optical and mechanical waves can be introduced through patterning of a material, provide one particularly attractive means for realizing strong interactions between high-frequency mechanical resonators and near-infrared light. Beyond the usual paradigm of cavity optomechanics involving isolated single mechanical elements, OMCs can also be fashioned into planar circuits for photons and phonons, and arrays of optomechanical elements can be interconnected via optical and acoustic waveguides. Such coupled OMC arrays have been proposed as a way to realize quantum optomechanical memories, nanomechanical circuits for continuous variable quantum information processing and phononic quantum networks, and as a platform for engineering and studying quantum many-body physics of optomechanical meta-materials. However, while ground state occupancies (that is, average phonon occupancies less than one) have been achieved in OMC cavities utilizing laser cooling techniques, parasitic absorption and the concomitant degradation of the mechanical quality factor fundamentally limit this approach. On the other hand, the high

  20. Cavity characterization for general use in linear electron accelerators

    International Nuclear Information System (INIS)

    Souza Neto, M.V. de.

    1985-01-01

    The main objective of this work is to is to develop measurement techniques for the characterization of microwave cavities used in linear electron accelerators. Methods are developed for the measurement of parameters that are essential to the design of an accelerator structure using conventional techniques of resonant cavities at low power. Disk-loaded cavities were designed and built, similar to those in most existing linear electron accelerators. As a result, the methods developed and the estimated accuracy were compared with those from other investigators. The results of this work are relevant for the design of cavities with the objective of developing linear electron accelerators. (author) [pt

  1. HOM frequency control of SRF cavity in high current ERLs

    Science.gov (United States)

    Xu, Chen; Ben-Zvi, Ilan

    2018-03-01

    The acceleration of high-current beam in Superconducting Radio Frequency (SRF) cavities is a challenging but essential for a variety of advanced accelerators. SRF cavities should be carefully designed to minimize the High Order Modes (HOM) power generated in the cavities by the beam current. The reduction of HOM power we demonstrate in a particular case can be quite large. This paper presents a method to systematically control the HOM resonance frequencies in the initial design phase to minimize the HOM power generation. This method is expected to be beneficial for the design of high SRF cavities addressing a variety of Energy Recovery Linac (ERL) applications.

  2. Pressure dependent resonant frequency of micromechanical drumhead resonators

    International Nuclear Information System (INIS)

    Southworth, D. R.; Craighead, H. G.; Parpia, J. M.

    2009-01-01

    We examine the relationship between squeeze film effects and resonance frequency in drum-type resonators. We find that the resonance frequency increases linearly with pressure as a result of the additional restoring force contribution from compression of gas within the drum cavity. We demonstrate trapping of the gas by squeeze film effects and geometry. The pressure sensitivity is shown to scale inversely with cavity height and sound radiation is found to be the predominant loss mechanism near and above atmospheric pressure. Drum resonators exhibit linearity and sensitivity suitable to barometry from below 10 Torr up to several atmospheres.

  3. Complex envelope control of pulsed accelerating fields in superconducting cavities

    CERN Document Server

    Czarski, T

    2010-01-01

    A digital control system for superconducting cavities of a linear accelerator is presented in this work. FPGA (Field Programmable Gate Arrays) based controller, managed by MATLAB, was developed to investigate a novel firmware implementation. The LLRF - Low Level Radio Frequency system for FLASH project in DESY is introduced. Essential modeling of a cavity resonator with signal and power analysis is considered as a key approach to the control methods. An electrical model is represented by the non-stationary state space equation for the complex envelope of the cavity voltage driven by the current generator and the beam loading. The electromechanical model of the superconducting cavity resonator including the Lorentz force detuning has been developed for a simulation purpose. The digital signal processing is proposed for the field vector detection. The field vector sum control is considered for multiple cavities driven by one klystron. An algebraic, complex domain model is proposed for the system analysis. The c...

  4. The LHC superconducting cavities

    CERN Document Server

    Boussard, Daniel; Häbel, E; Kindermann, H P; Losito, R; Marque, S; Rödel, V; Stirbet, M

    1999-01-01

    The LHC RF system, which must handle high intensity (0.5 A d.c.) beams, makes use of superconducting single-cell cavities, best suited to minimizing the effects of periodic transient beam loading. There will be eight cavities per beam, each capable of delivering 2 MV (5 MV/m accelerating field) at 400 MHz. The cavities themselves are now being manufactured by industry, using niobium-on-copper technology which gives full satisfaction at LEP. A cavity unit includes a helium tank (4.5 K operating temperature) built around a cavity cell, RF and HOM couplers and a mechanical tuner, all housed in a modular cryostat. Four-unit modules are ultimately foreseen for the LHC (two per beam), while at present a prototype version with two complete units is being extensively tested. In addition to a detailed description of the cavity and its ancillary equipment, the first test results of the prototype will be reported.

  5. The splitring loaded RF-cavity

    Science.gov (United States)

    Müller, Eckhard; Klein, Horst

    1984-07-01

    Experimental and theoretical work was done on the splitring loaded resonant rf-cavity. Formulae are derived for the determination of the resonance frequencies, Rp-value and shunt impedance dependent on the resonator geometry. The calculations were verified by experiments carried out by the authors as well as by measurements reported in literature. The theoretical and experimental optimizations were incorporated in a construction of a normal-conducting section laid out for a resonance frequency of 108 MHz, a particle velocity corresponding to β = v/ c = 0.057 and with an Rp-value of 14.5 MΩ producing an acceleration voltage of 1 MV. This resonator is part of a small postaccelerator, installed at the Frankfurt single-ended 7 MV CN Van de Graaff generator and has been tested with a particle beam.

  6. Progressive and resonant wave helices application to electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Volino, F.

    1969-01-01

    We show that helices can be used as resonant systems. Their properties are theoretically and experimentally studied. We describe resonant helices for electron paramagnetic resonance in X-band and develop a comparison between their sensitivity and the sensitivity of a normal resonant cavity. For cylindrical samples less than 3 mm diameter, the helix is more sensitive and can produce more intense microwave magnetic fields. (author) [fr

  7. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  8. Signatures of Nonlinear Cavity Optomechanics in the Weak Coupling Regime

    Science.gov (United States)

    Børkje, K.; Nunnenkamp, A.; Teufel, J. D.; Girvin, S. M.

    2013-08-01

    We identify signatures of the intrinsic nonlinear interaction between light and mechanical motion in cavity optomechanical systems. These signatures are observable even when the cavity linewidth exceeds the optomechanical coupling rate. A strong laser drive red detuned by twice the mechanical frequency from the cavity resonance frequency makes two-phonon processes resonant, which leads to a nonlinear version of optomechanically induced transparency. This effect provides a new method of measuring the average phonon number of the mechanical oscillator. Furthermore, we show that if the strong laser drive is detuned by half the mechanical frequency, optomechanically induced transparency also occurs due to resonant two-photon processes. The cavity response to a second probe drive is in this case nonlinear in the probe power. These effects should be observable with optomechanical coupling strengths that have already been realized in experiments.

  9. Coherent acoustic excitation of cavity polaritons

    DEFF Research Database (Denmark)

    Poel, Mike van der; de Lima, M. M.; Hey, R.

    and highly nonlinear optical response.Our sample consists of epitaxially grown GaAs/AlGaAs QWs located at the anti-node ofa high Q lambda cavity, which is resonant with the QW excitonic transition3. The SAWfield, which is excited by an interdigital transducer on the piezoelectric GaAs samplesurface......, modulates the refractive index and displaces the material causing a harmonicmodulation of the PBG structure1. This periodic modulation of the cavity-exciton systemleads to in-plane mini-Brillouin zone (MBZ) formation. The very high vacuum-Rabisplitting of our sample enables us to clearly resolve...

  10. Accelerating RF cavity of the Booster

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    Each of the 4 PS Booster rings has a single accelerating cavity. It consists of 2 quarter-wave ferrite-loaded resonators. There are 2 figure-of-eight loops on the ferrite loads for tuning the frequency throughout the acceleration cycle, from 3 to 8 MHz (from 50 MeV at injection to the original Booster energy of 800 MeV, 2 GeV today). The cavities have a flat design, to fit the ring-to-ring distance of 36 cm. The tube for forced-air cooling is visible in the left front. See also 8301084.

  11. Accelerating RF cavity of the Booster

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Each of the 4 PS Booster rings has a single accelerating cavity.It consists of 2 quarter-wave ferrite-loaded resonators. 2 figure-of-eight loops tune the frequency throughout the accelerating cycle, from 3 to 8 MHz (from 50 MeV at injection to the original Booster energy of 800 MeV, 2 GeV today). The cavities have a flat design, to fit the ring-to-ring distance of 36 cm, and are forced-air cooled. The 2 round objects in the front-compartments are the final-stage power-tetrodes. See also 8111095.

  12. Niobium coaxial quarter-wave cavities for the New Delhi booster linac

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W. [Argonne National Lab., IL (United States); Roy, A.; Potukuchi, P.N. [Nuclear Science Centre, New Delhi (India)

    1993-07-01

    This paper reports the design and construction status of a prototype superconducting niobium accelerating structure consisting of a pair of quarter-wave coaxial-line cavities which are strongly coupled with a superconducting loop. Quarter-wave resonators are two-gap accelerating structures and are relatively short, so that a large number of independently-phased cavities is required for a linac. Strongly coupling several cavities can reduce the number of independently-phased elements, but at the cost of reducing the range of useful velocity acceptance for each element. Coupling two cavities splits the accelerating rf eigenmode into two resonant modes each of which covers a portion of the full velocity acceptance range of the original single cavity mode. Using both of these resonant modes makes feasible the use of coupled cavity pairs for a linac with little loss m velocity acceptance. Design details for the niobium cavity pair and the results of preliminary tests of multipacting behavior are discussed.

  13. Niobium coaxial quarter-wave cavities for the New Delhi booster linac

    International Nuclear Information System (INIS)

    Shepard, K.W.; Roy, A.; Potukuchi, P.N.

    1993-01-01

    This paper reports the design and construction status of a prototype superconducting niobium accelerating structure consisting of a pair of quarter-wave coaxial-line cavities which are strongly coupled with a superconducting loop. Quarter-wave resonators are two-gap accelerating structures and are relatively short, so that a large number of independently-phased cavities is required for a linac. Strongly coupling several cavities can reduce the number of independently-phased elements, but at the cost of reducing the range of useful velocity acceptance for each element. Coupling two cavities splits the accelerating rf eigenmode into two resonant modes each of which covers a portion of the full velocity acceptance range of the original single cavity mode. Using both of these resonant modes makes feasible the use of coupled cavity pairs for a linac with little loss m velocity acceptance. Design details for the niobium cavity pair and the results of preliminary tests of multipacting behavior are discussed

  14. 17 GHz photonic band gap cavity with improved input coupling

    Directory of Open Access Journals (Sweden)

    M. A. Shapiro

    2001-04-01

    Full Text Available We present the theoretical design and cold test of a 17 GHz photonic band gap (PBG cavity with improved coupling from an external rectangular waveguide. The PBG cavity is made of a triangular lattice of metal rods with a defect (missing rod in the center. The TM_{010}-like defect mode was chosen as the operating mode. Experimental results are presented demonstrating that critical coupling into the cavity can be achieved by partial withdrawal or removal of some rods from the lattice, a result that agrees with simulations. A detailed design of the PBG accelerator structure is compared with a conventional (pillbox cavity. One advantage of the PBG cavity is that its resonance frequency is much less perturbed by the input/output coupling structure than in a comparable pillbox cavity. The PBG structure is attractive for future accelerator applications.

  15. Superconducting cavities for LEP

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Above: a 350 MHz superconducting accelerating cavity in niobium of the type envisaged for accelerating electrons and positrons in later phases of LEP. Below: a small 1 GHz cavity used for investigating the surface problems of superconducting niobium. Albert Insomby stays on the right. See Annual Report 1983 p. 51.

  16. Analytic Solution of the Electromagnetic Eigenvalues Problem in a Cylindrical Resonator

    Energy Technology Data Exchange (ETDEWEB)

    Checchin, Mattia [Fermilab; Martinello, Martina [Fermilab

    2016-10-06

    Resonant accelerating cavities are key components in modern particles accelerating facilities. These take advantage of electromagnetic fields resonating at microwave frequencies to accelerate charged particles. Particles gain finite energy at each passage through a cavity if in phase with the resonating field, reaching energies even of the order of $TeV$ when a cascade of accelerating resonators are present. In order to understand how a resonant accelerating cavity transfers energy to charged particles, it is important to determine how the electromagnetic modes are exited into such resonators. In this paper we present a complete analytical calculation of the resonating fields for a simple cylindrical-shaped cavity.

  17. Metamaterial Perfect Absorber Analyzed by a Meta Cavity Model Consisting of Multilayer Metasurfaces (Postprint)

    Science.gov (United States)

    2017-09-05

    The phase condition in Eq. 3 suggests a Fabry-Perot cavity-like mechanism. The cross-wire acts as a “mirror” that reflects light due to its high...is achieved by the Fabry-Perot cavity resonance via multiple reflections between the “quasi-open” boundary of resonator and the “close” boundary of...achieved by the Fabry- Perot cavity resonance via multiple reflections between the “quasi-open” boundary of resonator and the “close” boundary of

  18. SPS RF Cavity

    CERN Multimedia

    1975-01-01

    The picture shows one of the two initially installed cavities. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also gradually increased: by end 1980 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412017X, 7411048X, 7505074.

  19. SPS RF Accelerating Cavity

    CERN Multimedia

    1979-01-01

    This picture shows one of the 2 new cavities installed in 1978-1979. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X

  20. The Design of the Orthogonal Box Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Moretti, Alfred; /Fermilab

    2010-09-15

    The muon collider and/or the neutrino factory require large accelerating electric field gradients immersed in large (3 to 6 T) solenoidal magnetic fields for ionization cooling of muon beams. Our original vacuum breakdown study demonstrated a loss of achievable peak accelerating gradient in solenoidal magnetic fields by a factor 2 or greater. The Muon Collaboration has developed a theory of a method to suppress high electric field breakdown in vacuum cavities needed for a Muon collider or neutrino factory. It has been shown in our studies and by others that high gradient electric field emitted electrons (dark current) are the primary cause of breakdown. A DC magnetic field orthogonal to the RF electric accelerating field prevents dark current high field emitted electrons from traveling across the accelerating gap and then will prevent breakdown. We have decided to test this theory by building a special cavity in the shape of vacuum box. Figure 1 is a simplified view of the cavity design. The design is based on an 805 MHz WR975 waveguide cavity resonating in the TE{sub 101} mode. For the TE{sub 101} mode the resonant frequency f{sub 0} is given by the relationship f{sub 0} = c[(I/a){sup 2} + (m/b){sup 2} + (n/d){sup 2}]{sup 0.5}/2 where a and d are the lengths of the base sides and b is the height of the box in MKS units and c is the velocity of light.

  1. Superconducting TESLA cavities

    Directory of Open Access Journals (Sweden)

    B. Aune

    2000-09-01

    Full Text Available The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of E_{acc}≥25 MV/m at a quality factor Q_{0}≥5×10^{9}. The design goal for the cavities of the TESLA Test Facility (TTF linac was set to the more moderate value of E_{acc}≥15 MV/m. In a first series of 27 industrially produced TTF cavities the average gradient at Q_{0}=5×10^{9} was measured to be 20.1±6.2 MV/m, excluding a few cavities suffering from serious fabrication or material defects. In the second production of 24 TTF cavities, additional quality control measures were introduced, in particular, an eddy-current scan to eliminate niobium sheets with foreign material inclusions and stringent prescriptions for carrying out the electron-beam welds. The average gradient of these cavities at Q_{0}=5×10^{9} amounts to 25.0±3.2 MV/m with the exception of one cavity suffering from a weld defect. Hence only a moderate improvement in production and preparation techniques will be needed to meet the ambitious TESLA goal with an adequate safety margin. In this paper we present a detailed description of the design, fabrication, and preparation of the TESLA Test Facility cavities and their associated components and report on cavity performance in test cryostats and with electron beam in the TTF linac. The ongoing research and development towards higher gradients is briefly addressed.

  2. Hydroforming of elliptical cavities

    Directory of Open Access Journals (Sweden)

    W. Singer

    2015-02-01

    Full Text Available Activities of the past several years in developing the technique of forming seamless (weldless cavity cells by hydroforming are summarized. An overview of the technique developed at DESY for the fabrication of single cells and multicells of the TESLA cavity shape is given and the major rf results are presented. The forming is performed by expanding a seamless tube with internal water pressure while simultaneously swaging it axially. Prior to the expansion the tube is necked at the iris area and at the ends. Tube radii and axial displacements are computer controlled during the forming process in accordance with results of finite element method simulations for necking and expansion using the experimentally obtained strain-stress relationship of tube material. In cooperation with industry different methods of niobium seamless tube production have been explored. The most appropriate and successful method is a combination of spinning or deep drawing with flow forming. Several single-cell niobium cavities of the 1.3 GHz TESLA shape were produced by hydroforming. They reached accelerating gradients E_{acc} up to 35  MV/m after buffered chemical polishing (BCP and up to 42  MV/m after electropolishing (EP. More recent work concentrated on fabrication and testing of multicell and nine-cell cavities. Several seamless two- and three-cell units were explored. Accelerating gradients E_{acc} of 30–35  MV/m were measured after BCP and E_{acc} up to 40  MV/m were reached after EP. Nine-cell niobium cavities combining three three-cell units were completed at the company E. Zanon. These cavities reached accelerating gradients of E_{acc}=30–35  MV/m. One cavity is successfully integrated in an XFEL cryomodule and is used in the operation of the FLASH linear accelerator at DESY. Additionally the fabrication of bimetallic single-cell and multicell NbCu cavities by hydroforming was successfully developed. Several NbCu clad single-cell and

  3. Multicolor cavity soliton.

    Science.gov (United States)

    Luo, Rui; Liang, Hanxiao; Lin, Qiang

    2016-07-25

    We show a new class of complex solitary wave that exists in a nonlinear optical cavity with appropriate dispersion characteristics. The cavity soliton consists of multiple soliton-like spectro-temporal components that exhibit distinctive colors but coincide in time and share a common phase, formed together via strong inter-soliton four-wave mixing and Cherenkov radiation. The multicolor cavity soliton shows intriguing spectral locking characteristics and remarkable capability of spectrum management to tailor soliton frequencies, which would be very useful for versatile generation and manipulation of multi-octave spanning phase-locked Kerr frequency combs, with great potential for applications in frequency metrology, optical frequency synthesis, and spectroscopy.

  4. Tuned optical cavity magnetometer

    Science.gov (United States)

    Okandan, Murat; Schwindt, Peter

    2010-11-02

    An atomic magnetometer is disclosed which utilizes an optical cavity formed from a grating and a mirror, with a vapor cell containing an alkali metal vapor located inside the optical cavity. Lasers are used to magnetically polarize the alkali metal vapor and to probe the vapor and generate a diffracted laser beam which can be used to sense a magnetic field. Electrostatic actuators can be used in the magnetometer for positioning of the mirror, or for modulation thereof. Another optical cavity can also be formed from the mirror and a second grating for sensing, adjusting, or stabilizing the position of the mirror.

  5. Cavity electromagnetically induced transparency with Rydberg atoms

    Science.gov (United States)

    Bakar Ali, Abu; Ziauddin

    2018-02-01

    Cavity electromagnetically induced transparency (EIT) is revisited via the input probe field intensity. A strongly interacting Rydberg atomic medium ensemble is considered in a cavity, where atoms behave as superatoms (SAs) under the dipole blockade mechanism. Each atom in the strongly interacting Rydberg atomic medium (87 Rb) follows a three-level cascade atomic configuration. A strong control and weak probe field are employed in the cavity with the ensemble of Rydberg atoms. The features of the reflected and transmitted probe light are studied under the influence of the input probe field intensity. A transparency peak (cavity EIT) is revealed at a resonance condition for small values of input probe field intensity. The manipulation of the cavity EIT is reported by tuning the strength of the input probe field intensity. Further, the phase and group delay of the transmitted and reflected probe light are studied. It is found that group delay and phase in the reflected light are negative, while for the transmitted light they are positive. The magnitude control of group delay in the transmitted and reflected light is investigated via the input probe field intensity.

  6. Long Wave Infrared Cavity Enhanced Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Taubman, Matthew S.; Scott, David C.; Cannon, Bret D.; Myers, Tanya L.; Bonebrake, Christopher A.; Aker, Pam M.; Wojcik, Michael D.; Munley, John T.; Nguyen, Vinh T.; Schultz, John F.

    2004-10-01

    The principal goal of Pacific Northwest National Laboratory's (PNNL's) long wave infrared (LWIR) cavity enhanced sensor (CES) project is to explore ultra-sensitive spectroscopic techniques and apply them to the development of LWIR chemical sensors needed for detecting weapons proliferation. This includes detecting not only the weapons of mass destruction (WMDs) themselves, but also signatures of their production and/or detonation. The LWIR CES project is concerned exclusively with developing point sensors; other portions of PNNL's IR Sensors program address stand off detection. PNNL's LWIR CES research is distinguished from that done by others by the use quantum cascade lasers (QCLs) as the light source. QCLs are novel devices, and a significant fraction of our research has been devoted to developing the procedures and hardware required to implement them most effectively for chemical sensing. This report details the progress we have made on our LWIR CES sensor development. During FY02, PNNL investigated three LWIR CES implementations beginning with the easiest to implement, direct cavity-enhanced detection (simple CES), including a technique of intermediate difficulty, cavity-dithered phase-sensitive detection (FM recovery CES) through to the most complex technique, that of resonant sideband cavity-enhanced detection also known as noise-immune cavity-enhanced optical heterodyne molecular spectroscopy, or NICE-OHMS.

  7. accelerating cavity from LEP

    CERN Multimedia

    This is an accelerating cavity from LEP, with a layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities are now used in LEP to double the energy of the particle beams.

  8. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    The SPS started up with 2 accelerating cavities (each consisting of 5 tank sections) in LSS3. They have a 200 MHz travelling wave structure (see 7411032 and 7802190) and 750 kW of power is fed to each of the cavities from a 1 MW tetrode power amplifier, located in a surface building above, via a coaxial transmission line. Clemens Zettler, builder of the SPS RF system, is standing at the side of one of the cavities. In 1978 and 1979 another 2 cavities were added and entered service in 1980. These were part of the intensity improvement programme and served well for the new role of the SPS as proton-antiproton collider. See also 7411032, 8011289, 8104138, 8302397.

  9. Coherent Dynamics of Quantum Dots in Photonic-Crystal Cavities

    DEFF Research Database (Denmark)

    Madsen, Kristian Høeg

    In this thesis we have performed quantum-electrodynamics experiments on quantum dots embedded in photonic-crystal cavities. We perform a quantitative comparison of the decay dynamics and emission spectra of quantum dots embedded in a micropillar cavity and a photonic-crystal cavity. The light......-matter interaction in the micropiller caivty is so strong that we measure non-Markovian dynamics of the quantum dot, and we compare to the Jaynes-Cummings model with all parameters independently determined. We find an excellent agreement when comparing the dynamics, but the emission spectra show significant...... deviations. Similar measurements on a quantum dot in a photonic-crystal cavity sow a Rabi splitting on resonance, while time-resolved measurements prove that the system is in the weak coupling regime. Whle tuning the quantum dot through resonance of the high-Q mode we observe a strong and surprisingly...

  10. Cavity state manipulation using a dispersively coupled qubit

    Science.gov (United States)

    Heeres, Reinier; Vlastakis, Brian; Holland, Eric; Krastanov, Stefan; Albert, Victor V.; Shen, Chao; Jiang, Liang; Schoelkopf, Robert

    2015-03-01

    The large available Hilbert space and high coherence of cavity resonators makes them an interesting resource in quantum information processing. For example, several schemes exist to encode a logical qubit in such a harmonic oscillator in a way that would be protected against certain kinds of errors. Here we demonstrate a method to manipulate a cavity state using a far off-resonantly coupled qubit, using only linear controls and a gate we call the Selective Number Arbitrary Phase (SNAP) gate. This gate allows to impart an arbitrary phase on each Fock-state component of the cavity. We show how we can use these tools to correct for the effects of Kerr-evolution as well as how to create a single-photon Fock state. Our scheme can be generalized to arbitrary cavity state creation and even allows to construct arbitrary unitary operators to give universal control of the oscillator.

  11. Hybrid vertical cavity laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  12. The Superconducting TESLA Cavities

    CERN Document Server

    Aune, B.; Bloess, D.; Bonin, B.; Bosotti, A.; Champion, M.; Crawford, C.; Deppe, G.; Dwersteg, B.; Edwards, D.A.; Edwards, H.T.; Ferrario, M.; Fouaidy, M.; Gall, P-D.; Gamp, A.; Gössel, A.; Graber, J.; Hubert, D.; Hüning, M.; Juillard, M.; Junquera, T.; Kaiser, H.; Kreps, G.; Kuchnir, M.; Lange, R.; Leenen, M.; Liepe, M.; Lilje, L.; Matheisen, A.; Möller, W-D.; Mosnier, A.; Padamsee, H.; Pagani, C.; Pekeler, M.; Peters, H-B.; Peters, O.; Proch, D.; Rehlich, K.; Reschke, D.; Safa, H.; Schilcher, T.; Schmüser, P.; Sekutowicz, J.; Simrock, S.; Singer, W.; Tigner, M.; Trines, D.; Twarowski, K.; Weichert, G.; Weisend, J.; Wojtkiewicz, J.; Wolff, S.; Zapfe, K.

    2000-01-01

    The conceptional design of the proposed linear electron-positron colliderTESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with anaccelerating gradient of Eacc >= 25 MV/m at a quality factor Q0 > 5E+9. Thedesign goal for the cavities of the TESLA Test Facility (TTF) linac was set tothe more moderate value of Eacc >= 15 MV/m. In a first series of 27industrially produced TTF cavities the average gradient at Q0 = 5E+9 wasmeasured to be 20.1 +- 6.2 MV/m, excluding a few cavities suffering fromserious fabrication or material defects. In the second production of 24 TTFcavities additional quality control measures were introduced, in particular aneddy-current scan to eliminate niobium sheets with foreign material inclusionsand stringent prescriptions for carrying out the electron-beam welds. Theaverage gradient of these cavities at Q0 = 5E+9 amounts to 25.0 +- 3.2 MV/mwith the exception of one cavity suffering from a weld defect. Hence only amoderate improvement in production and preparation technique...

  13. Husimi functions at gradient index cavities designed by conformal transformation optics.

    Science.gov (United States)

    Kim, Inbo; Cho, Jinhang; Kim, Yushin; Min, Bumki; Ryu, Jung-Wan; Rim, Sunghwan; Choi, Muhan

    2018-03-19

    Dielectric cavity systems, which have been studied extensively so far, have uniform refractive indices of their cavities, and Husimi functions, the most widely used phase space representation of optical modes formed in the cavities, accordingly were derived only for these homogeneous index cavities. For the case of the recently proposed gradient index dielectric cavities (called as transformation cavities) designed by optical conformal mapping, we show that the phase space structure of resonant modes can be revealed through the conventional Husimi functions by constructing a reciprocal virtual space. As examples, the Husimi plots were obtained for an anisotropic whispering gallery mode (WGM) and a short-lived mode supported in a limaçon-shaped transformation cavity. The phase space description of the corresponding modes in the reciprocal virtual space is compatible with the far-field directionality of the resonant modes in the physical space.

  14. Electrical control of silicon photonic crystal cavity by graphene.

    Science.gov (United States)

    Majumdar, Arka; Kim, Jonghwan; Vuckovic, Jelena; Wang, Feng

    2013-02-13

    The efficient conversion of an electrical signal to an optical signal in nanophotonics enables solid state integration of electronics and photonics. The combination of graphene with photonic crystals is promising for electro-optic modulation. In this paper, we demonstrate that by electrostatic gating a single layer of graphene on top of a photonic crystal cavity, the cavity resonance can be changed significantly. A ~2 nm change in the cavity resonance line width and almost 400% (6 dB) change in resonance reflectivity is observed. In addition, our analysis shows that a graphene-photonic crystal device can potentially be useful for a high speed and low power absorptive and refractive modulator, while maintaining a small physical footprint.

  15. Polarisation dynamics of a birefringent Fabry-Perot cavity

    Science.gov (United States)

    Ejlli, A.; Della Valle, F.; Zavattini, G.

    2018-02-01

    Optical Fabry-Perot cavities always show a non-degeneracy of two orthogonal polarisation states. This is due to the unavoidable birefringence of dielectric mirrors whose effects are extremely important in Fabry-Perot-based high-accuracy polarimeters: in birefringent cavities, ellipticities and rotations mix. We have developed and present here a theory of the polarisation state dynamics in a birefringent Fabry-Perot resonator, and we validate it through measurements performed with the polarimeter of the PVLAS experiment. The measurements are performed while a laser is frequency-locked to the cavity, and provide values for the phase difference between the two orthogonal polarisation components introduced by the combination of the two cavity mirrors (equivalent wave-plate) and for the finesse of the cavity. The theoretical formulas and the experimental data agree well showing that the consequences of the mirror birefringence must be taken into account in this and in any other similar experiment.

  16. Benchmarking Microwave Cavity Dark Matter Searches using a Radioactive Source

    CERN Multimedia

    Caspers, F

    2014-01-01

    A radioactive source is proposed as a calibration device to verify the sensitivity of a microwave dark matter search experiment. The interaction of e.g., electrons travelling in an arbitrary direction and velocity through an electromagnetically “empty” microwave cavity can be calculated numerically. We give an estimation of the energy deposited by a charged particle into a particular mode. Numerical examples are given for beta emitters and two particular cases: interaction with a field free cavity and interaction with a cavity which already contains an electromagnetic field. Each particle delivers a certain amount of energy related to the modal R/Q value of the cavity. The transferred energy is a function of the particles trajectory and its velocity. It results in a resonant response of the cavity, which can be observed using a sensitive microwave receiver, provided that the deposited energy is significantly above the single photon threshold.

  17. A Pass Band Performance Simulation Code of Coupled Cavities

    CERN Document Server

    Tao, X

    2004-01-01

    A simulation code of accelerating cavities named PPSC is developed by the solutions of the microwave equivalent circuit equations. PPSC can give the pass band performance of periodic or non-periodic accelerating structures, such as the dispersion frequency and the reflection factor of the cavity, the field distribution of each mode and so on. The natural parameters of the structure, such as the number of the cavities, the resonant frequencies and Q-factors of each cavity, the coupling factor between two cavities, and the locations of the couplers, can be changed easily to see the different results of the simulation. The code is written based on MS Visual Basic under MS windows. With these, a user-friendly interface is made. Some simple examples was simulated and gave reliable results.

  18. Novel High Cooperativity Photon-Magnon Cavity QED

    Science.gov (United States)

    Tobar, Michael; Bourhill, Jeremy; Kostylev, Nikita; G, Maxim; Creedon, Daniel

    Novel microwave cavities are presented, which couple photons and magnons in YIG spheres in a super- and ultra-strong way at around 20 mK in temperature. Few/Single photon couplings (or normal mode splitting, 2g) of more than 6 GHz at microwave frequencies are obtained. Types of cavities include multiple post reentrant cavities, which co-couple photons at different frequencies with a coupling greater that the free spectral range, as well as spherical loaded dielectric cavity resonators. In such cavities we show that the bare dielectric properties can be obtained by polarizing all magnon modes to high energy using a 7 Tesla magnet. We also show that at zero-field, collective effects of the spins significantly perturb the photon modes. Other effects like time-reversal symmetry breaking are observed.

  19. Paired modes of heterostructure cavities in photonic crystal waveguides with split band edges

    DEFF Research Database (Denmark)

    Mahmoodian, Sahand; Sukhorukov, Andrey A.; Ha, Sangwoo

    2010-01-01

    We investigate the modes of double heterostructure cavities where the underlying photonic crystal waveguide has been dispersion engineered to have two band-edges inside the Brillouin zone. By deriving and using a perturbative method, we show that these structures possess two modes. For unapodized...... cavities, the relative detuning of the two modes can be controlled by changing the cavity length, and for particular lengths, a resonant-like effect makes the modes degenerate. For apodized cavities no such resonances exist and the modes are always non-degenerate....

  20. Squeezing-enhanced measurement sensitivity in a cavity optomechanical system

    DEFF Research Database (Denmark)

    Kerdoncuff, Hugo; Hoff, Ulrich Busk; Harris, Glen I.

    2015-01-01

    We determine the theoretical limits to squeezing-enhanced measurement sensitivity of mechanical motion in a cavity optomechanical system. The motion of a mechanical resonator is transduced onto quadrature fluctuations of a cavity optical field and a measurement is performed on the optical field...... exiting the cavity. We compare measurement sensitivities obtained with coherent probing and quantum-enhanced probing of the mechanical motion, i.e. the coherent probe field carries vacuum states and quadrature squeezed vacuum states at sideband frequencies, respectively. We find that quantum...

  1. Electromagnetic Wave Chaos in Gradient Refractive Index Optical Cavities

    International Nuclear Information System (INIS)

    Wilkinson, P. B.; Fromhold, T. M.; Taylor, R. P.; Micolich, A. P.

    2001-01-01

    Electromagnetic wave chaos is investigated using two-dimensional optical cavities formed in a cylindrical gradient refractive index lens with reflective surfaces. When the planar ends of the lens are cut at an angle to its axis, the geometrical ray paths are chaotic. In this regime, the electromagnetic mode spectrum of the cavity is modulated by both real and ghost periodic ray paths, which also 'scar' the electric field intensity distributions of many modes. When the cavity is coupled to waveguides, the eigenmodes generate complex series of resonant peaks in the electromagnetic transmission spectrum

  2. Nonreciprocal lasing in topological cavities of arbitrary geometries

    Science.gov (United States)

    Bahari, Babak; Ndao, Abdoulaye; Vallini, Felipe; El Amili, Abdelkrim; Fainman, Yeshaiahu; Kanté, Boubacar

    2017-11-01

    Resonant cavities are essential building blocks governing many wave-based phenomena, but their geometry and reciprocity fundamentally limit the integration of optical devices. We report, at telecommunication wavelengths, geometry-independent and integrated nonreciprocal topological cavities that couple stimulated emission from one-way photonic edge states to a selected waveguide output with an isolation ratio in excess of 10 decibels. Nonreciprocity originates from unidirectional edge states at the boundary between photonic structures with distinct topological invariants. Our experimental demonstration of lasing from topological cavities provides the opportunity to develop complex topological circuitry of arbitrary geometries for the integrated and robust generation and transport of photons in classical and quantum regimes.

  3. Design of the Advanced Virgo non-degenerate recycling cavities

    International Nuclear Information System (INIS)

    Granata, M; Barsuglia, M; Flaminio, R; Freise, A; Hild, S; Marque, J

    2010-01-01

    Advanced Virgo is the project to upgrade the interferometric gravitational wave detector Virgo, and it foresees the implementation of power and signal non-degenerate recycling cavities. Such cavities suppress the build-up of high order modes of the resonating sidebands, with some advantage for the commissioning of the detector and the build-up of the gravitational signal. Here we present the baseline design of the Advanced Virgo non-degenerate recycling cavities, giving some preliminary results of simulations about the tolerances of this design to astigmatism, mirror figure errors and thermal lensing.

  4. Resonant coupling applied to superconducting accelerator structures

    International Nuclear Information System (INIS)

    Potter, James M.; Krawczyk, Frank L.

    2013-01-01

    The concept of resonant coupling and the benefits that accrue from its application is well known in the world of room temperature coupled cavity linacs. Design studies show that it can be applied successfully between sections of conventional elliptical superconducting coupled cavity accelerator structures and internally to structures with spoked cavity resonators. The coupling mechanisms can be designed without creating problems with high field regions or multipactoring. The application of resonant coupling to superconducting accelerators eliminates the need for complex cryogenic mechanical tuners and reduces the time needed to bring a superconducting accelerator into operation.

  5. Porous photonic crystal external cavity laser biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qinglan [Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Peh, Jessie; Hergenrother, Paul J. [Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Cunningham, Brian T. [Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    2016-08-15

    We report the design, fabrication, and testing of a photonic crystal (PC) biosensor structure that incorporates a porous high refractive index TiO{sub 2} dielectric film that enables immobilization of capture proteins within an enhanced surface-area volume that spatially overlaps with the regions of resonant electromagnetic fields where biomolecular binding can produce the greatest shifts in photonic crystal resonant wavelength. Despite the nanoscale porosity of the sensor structure, the PC slab exhibits narrowband and high efficiency resonant reflection, enabling the structure to serve as a wavelength-tunable element of an external cavity laser. In the context of sensing small molecule interactions with much larger immobilized proteins, we demonstrate that the porous structure provides 3.7× larger biosensor signals than an equivalent nonporous structure, while the external cavity laser (ECL) detection method provides capability for sensing picometer-scale shifts in the PC resonant wavelength caused by small molecule binding. The porous ECL achieves a record high figure of merit for label-free optical biosensors.

  6. Wavelength-Agile External-Cavity Diode Laser for DWDM

    Science.gov (United States)

    Pilgrim, Jeffrey S.; Bomse, David S.

    2006-01-01

    A prototype external-cavity diode laser (ECDL) has been developed for communication systems utilizing dense wavelength- division multiplexing (DWDM). This ECDL is an updated version of the ECDL reported in Wavelength-Agile External- Cavity Diode Laser (LEW-17090), NASA Tech Briefs, Vol. 25, No. 11 (November 2001), page 14a. To recapitulate: The wavelength-agile ECDL combines the stability of an external-cavity laser with the wavelength agility of a diode laser. Wavelength is modulated by modulating the injection current of the diode-laser gain element. The external cavity is a Littman-Metcalf resonator, in which the zeroth-order output from a diffraction grating is used as the laser output and the first-order-diffracted light is retro-reflected by a cavity feedback mirror, which establishes one end of the resonator. The other end of the resonator is the output surface of a Fabry-Perot resonator that constitutes the diode-laser gain element. Wavelength is selected by choosing the angle of the diffracted return beam, as determined by position of the feedback mirror. The present wavelength-agile ECDL is distinguished by design details that enable coverage of all 60 channels, separated by 100-GHz frequency intervals, that are specified in DWDM standards.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  8. Benchmarking state-of-the-art numerical simulation techniques for analyzing large photonic crystal membrane line defect cavities

    DEFF Research Database (Denmark)

    Gregersen, Niels; de Lasson, Jakob Rosenkrantz; Frandsen, Lars Hagedorn

    2018-01-01

    In this work, we perform numerical studies of two photonic crystal membrane microcavities, a short line-defect L5 cavity with relatively low quality (Q) factor and a longer L9 cavity with high Q. We compute the cavity Q factor and the resonance wavelength λ of the fundamental M1 mode in the two...

  9. Materials for superconducting cavities

    International Nuclear Information System (INIS)

    Bonin, B.

    1996-01-01

    The ideal material for superconducting cavities should exhibit a high critical temperature, a high critical field, and, above all, a low surface resistance. Unfortunately, these requirements can be conflicting and a compromise has to be found. To date, most superconducting cavities for accelerators are made of niobium. The reasons for this choice are discussed. Thin films of other materials such as NbN, Nb 3 Sn, or even YBCO compounds can also be envisaged and are presently investigated in various laboratories. It is shown that their success will depend critically on the crystalline perfection of these films. (author)

  10. Experimental investigation of cavity flows

    Energy Technology Data Exchange (ETDEWEB)

    Loeland, Tore

    1998-12-31

    This thesis uses LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry) and Laser Sheet flow Visualisation to study flow inside three different cavity configurations. For sloping cavities, the vortex structure inside the cavities is found to depend upon the flow direction past the cavity. The shape of the downstream corner is a key factor in destroying the boundary layer flow entering the cavity. The experimental results agree well with numerical simulations of the same geometrical configurations. The results of the investigations are used to find the influence of the cavity flow on the accuracy of the ultrasonic flowmeter. A method to compensate for the cavity velocities is suggested. It is found that the relative deviation caused by the cavity velocities depend linearly on the pipe flow. It appears that the flow inside the cavities should not be neglected as done in the draft for the ISO technical report on ultrasonic flowmeters. 58 refs., 147 figs., 2 tabs.

  11. Three-dimensional self-consistent simulations of multipacting in superconducting radio frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Chet Nieter

    2010-12-01

    Superconducting radio frequency (SRF) cavities are a popular choice among researchers designing new accelerators because of the reduced power losses due to surface resistance. However, SRF cavities still have unresolved problems, including the loss of power to stray electrons. Sources of these electrons are field emission from the walls and ionization of background gas, but the predominant source is secondary emission yield (SEY) from electron impact. When the electron motion is in resonance with the cavity fields the electrons strike the cavity surface repeatedly creating a resonant build up of electrons referred to as multipacting. Cavity shaping has successfully reduced multipacting for cavities used in very high energy accelerators. However, multipacting is still a concern for the cavity power couplers, where shaping is not possible, and for cavities used to accelerate particles at moderate velocities. This Phase II project built upon existing models in the VORPAL simulation framework to allow for simulations of multipacting behavior in SRF cavities and their associated structures. The technical work involved allowed existing models of secondary electron generation to work with the complex boundary conditions needed to model the cavity structures. The types of data produced by VORPAL were also expanded to include data common used by cavity designers to evaluate cavity performance. Post-processing tools were also modified to provide information directly related to the conditions that produce multipacting. These new methods were demonstrated by running simulations of a cavity design being developed by researchers at Jefferson National Laboratory to attempt to identify the multipacting that would be an issue for the cavity design being considered. These simulations demonstrate that VORPAL now has the capabilities to assist researchers working with SRF cavities to understand and identify possible multipacting issues with their cavity designs.

  12. Wall compliance and violin cavity modes.

    Science.gov (United States)

    Bissinger, George

    2003-03-01

    Violin corpus wall compliance, which has a substantial effect on cavity mode frequencies, was added to Shaw's two-degree-of-freedom (2DOF) network model for A0 ("main air") and A1 (lowest length mode included in "main wood") cavity modes. The 2DOF model predicts a V(-0.25) volume dependence for A0 for rigid violin-shaped cavities, to which a semiempirical compliance correction term, V(-x(c)) (optimization parameter x(c)) consistent with cavity acoustical compliance and violin-based scaling was added. Optimizing x(c) over A0 and A1 frequencies measured for a Hutchins-Schelleng violin octet yielded x(c) approximately 0.08. This markedly improved A0 and A1 frequency predictions to within approximately +/- 10% of experiment over a range of about 4.5:1 in length, 10:1 in f-hole area, 3:1 in top plate thickness, and 128:1 in volume. Compliance is a plausible explanation for A1 falling close to the "main wood" resonance, not increasingly higher for the larger instruments, which were scaled successively shorter compared to the violin for ergonomic and practical reasons. Similarly incorporating compliance for A2 and A4 (lowest lower-/upper-bout modes, respectively) improves frequency predictions within +/-20% over the octet.

  13. Lasers with intra-cavity phase elements

    Science.gov (United States)

    Gulses, A. Alkan; Kurtz, Russell; Islas, Gabriel; Anisimov, Igor

    2018-02-01

    Conventional laser resonators yield multimodal output, especially at high powers and short cavity lengths. Since highorder modes exhibit large divergence, it is desirable to suppress them to improve laser quality. Traditionally, such modal discriminations can be achieved by simple apertures that provide absorptive loss for large diameter modes, while allowing the lower orders, such as the fundamental Gaussian, to pass through. However, modal discrimination may not be sufficient for short-cavity lasers, resulting in multimodal operation as well as power loss and overheating in the absorptive part of the aperture. In research to improve laser mode control with minimal energy loss, systematic experiments have been executed using phase-only elements. These were composed of an intra-cavity step function and a diffractive out-coupler made of a computer-generated hologram. The platform was a 15-cm long solid-state laser that employs a neodymium-doped yttrium orthovanadate crystal rod, producing 1064 nm multimodal laser output. The intra-cavity phase elements (PEs) were shown to be highly effective in obtaining beams with reduced M-squared values and increased output powers, yielding improved values of radiance. The utilization of more sophisticated diffractive elements is promising for more difficult laser systems.

  14. Superconducting elliptical cavities

    CERN Document Server

    Sekutowicz, J K

    2011-01-01

    We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along with examples of superconducting structures for various applications.

  15. LEP superconducting cavity

    CERN Multimedia

    1995-01-01

    Engineers work in a clean room on one of the superconducting cavities for the upgrade to the LEP accelerator, known as LEP-2. The use of superconductors allow higher electric fields to be produced so that higher beam energies can be reached.

  16. Niobium superconducting cavity

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    This 5-cell superconducting cavity, made from bulk-Nb, stems from the period of general studies, not all directed towards direct use at LEP. This one is dimensioned for 1.5 GHz, the frequency used at CEBAF and also studied at Saclay (LEP RF was 352.2 MHz). See also 7908227, 8007354, 8209255, 8210054, 8312339.

  17. What's a Cavity?

    Science.gov (United States)

    ... and deeper over time. Cavities are also called dental caries (say: KARE-eez), and if you have a ... made up mostly of the germs that cause tooth decay. The bacteria in your mouth make acids and when plaque clings to your teeth, the acids can eat away at the outermost ...

  18. Filling a Conical Cavity

    Science.gov (United States)

    Nye, Kyle; Eslam-Panah, Azar

    2016-11-01

    Root canal treatment involves the removal of infected tissue inside the tooth's canal system and filling the space with a dense sealing agent to prevent further infection. A good root canal treatment happens when the canals are filled homogeneously and tightly down to the root apex. Such a tooth is able to provide valuable service for an entire lifetime. However, there are some examples of poorly performed root canals where the anterior and posterior routes are not filled completely. Small packets of air can be trapped in narrow access cavities when restoring with resin composites. Such teeth can cause trouble even after many years and lead the conditions like acute bone infection or abscesses. In this study, the filling of dead-end conical cavities with various liquids is reported. The first case studies included conical cavity models with different angles and lengths to visualize the filling process. In this investigation, the rate and completeness at which a variety of liquids fill the cavity were observed to find ideal conditions for the process. Then, a 3D printed model of the scaled representation of a molar with prepared post spaces was used to simulate the root canal treatment. The results of this study can be used to gain a better understanding of the restoration for endodontically treated teeth.

  19. Sound absorption by a Helmholtz resonator

    Science.gov (United States)

    Komkin, A. I.; Mironov, M. A.; Bykov, A. I.

    2017-07-01

    Absorption characteristics of a Helmholtz resonator positioned at the end wall of a circular duct are considered. The absorption coefficient of the resonator is experimentally investigated as a function of the diameter and length of the resonator neck and the depth of the resonator cavity. Based on experimental data, the linear analytic model of a Helmholtz resonator is verified, and the results of verification are used to determine the dissipative attached length of the resonator neck so as to provide the agreement between experimental and calculated data. Dependences of sound absorption by a Helmholtz resonator on its geometric parameters are obtained.

  20. Novel deflecting cavity design for eRHIC

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q.; Belomestnykh, S.; Ben-Zvi, I.

    2011-07-25

    To prevent significant loss of the luminosity due to large crossing angle in the future ERL based Electron Ion Collider at BNL (eRHIC), there is a demand for crab cavities. In this article, we will present a novel design of the deflecting/crabbing 181 MHz superconducting RF cavity that will fulfil the requirements of eRHIC. The quarter-wave resonator structure of the new cavity possesses many advantages, such as compact size, high R{sub t}/Q, the absence of the same order mode and lower order mode, and easy higher order mode damping. We will present the properties and characteristics of the new cavity in detail. As the accelerator systems grow in complexity, developing compact and efficient deflecting cavities is of great interest. Such cavities will benefit situations where the beam line space is limited. The future linac-ring type electron-ion collider requires implementation of a crab-crossing scheme for both beams at the interaction region. The ion beam has a long bunches and high rigidity. Therefore, it requires a low frequency, large kicking angle deflector. The frequency of the deflecting mode for the current collider design is 181 MHz, and the deflecting angle is {approx}5 mrad for each beam. At such low frequency, the previous designs of the crab cavities will have very large dimensions, and also will be confronted by typical problems of damping the Lower Order Mode (LOM), the Same Order Mode (SOM), and as usual, the Higher Order Modes (HOM). In this paper we describe how one can use the concept of a quarter-wave (QW) resonator for a deflecting/crabbing cavity, and use its fundamental mode to deflect the beam. The simplicity of the cavity geometry and the large separation between its fundamental mode and the first HOM make it very attractive.

  1. Electro Polishing of Niobium Cavities at DESY

    CERN Document Server

    Matheisen, A; Morales, H; Petersen, B; Schmoekel, M; Steinhau-Kühl, N

    2004-01-01

    At DESY a facility for electro polishing (EP) of the super conducting (s.c.) TESLA/TTF cavities have been built and is operational since summer 2003. The EP infrastructure is capable to handle single-cell structures and the standard TESLA/ TTF nine-cell cavities. Several electro polishing processes have been made since and acceleration voltage up to 40 MV/m have been reached in nine cell structures. We report on measurements and experiences gained since 2003 as well as on handling procedures developed for the preparation of electro polished resonators. Specific data like heat production, variation of current density and bath aging will be presented. Another important point for reproducible results is the quality control of the electro polishing process. First quality control steps to be implanted in the EP procedure for large-scale production will be described.

  2. Multipass optical cavity for inverse Compton interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rollason, A.J. E-mail: a.j.rollason@keele.ac.uk; Fang, X.; Dugdale, D.E

    2004-07-01

    The recycling of laser beams in the focal region of non-resonant multipass optical cavities has been investigated as a means of providing a high intensity of photons for weak interaction experiments. Ray-tracing simulations and measurements with an Ar-ion laser have been carried out to examine the intensity profiles of the laser field in different 2-mirror geometries. In particular, the use of such cavities in the generation of X-rays by inverse Compton scattering is considered. X-ray yields are calculated for electron beams of 0.05, 0.1, 0.2 and 0.5 mm diameter yielding enhancement factors of 10-200 compared to a free space laser interaction.

  3. HOM Couplers for CERN SPL Cavities

    CERN Document Server

    Papke, Kai; Van Rienen, U

    2013-01-01

    Higher-Order-Modes (HOMs) may affect beam stability and refrigeration requirements of superconducting proton linacs such as the SPL, which is studied at CERN as the driver for future neutrino facilities. In order to limit beam-induced HOM effects, CERN considers the use of HOM couplers on the cut-off tubes of the 5-cell superconducting cavities. These couplers consist of resonant antennas shaped as loops or probes, which are designed to couple to modes of a specific frequency range. In this paper the design process is presented and a comparison is made between various design options for the medium and high-beta SPL cavities, both operating at 704.4 MHz. The RF characteristics and thermal behaviour of the various designs are discussed.

  4. Laser of optical fiber composed by two coupled cavities: application as optical fiber sensor

    International Nuclear Information System (INIS)

    Vazquez S, R.A.; Kuzin, E.A.; Ibarra E, B.; May A, M.; Shlyagin, M.; Marquez B, I.

    2004-01-01

    We show an optical fiber laser sensor which consist of two cavities coupled and three fiber Bragg gratings. We used one Bragg grating (called reference) and two Bragg gratings (called sensors), which have the lower reflection wavelength. The reference grating with the two sensors grating make two cavities: first one is the internal cavity which has 4230 m of length and the another one is the external cavity which has 4277 m of length. Measuring the laser beating frequency for a resonance cavity and moving the frequency peaks when the another cavity is put in resonance, we prove that the arrangement can be used as a two points sensor for determining the difference of temperature or stress between these two points. (Author)

  5. Fibre Coupled Photonic Crystal Cavity Arrays on Transparent Substrates for Spatially Resolved Sensing

    Directory of Open Access Journals (Sweden)

    Mark G. Scullion

    2014-11-01

    Full Text Available We introduce a photonic crystal cavity array realised in a silicon thin film and placed on polydimethlysiloxane (PDMS as a new platform for the in-situ sensing of biomedical processes. Using tapered optical fibres, we show that multiple independent cavities within the same waveguide can be excited and their resonance wavelength determined from camera images without the need for a spectrometer. The cavity array platform combines sensing as a function of location with sensing as a function of time.

  6. Design and prototyping of HL-LHC double quarter wave crab cavities for SPS test

    Energy Technology Data Exchange (ETDEWEB)

    Verdu-Andres, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Skaritka, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wu, Q. [Brookhaven National Lab. (BNL), Upton, NY (United States); Xiao, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Belomestnykh, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States); Ben-Zvi, I. [Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States); Alberty, L. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Artoos, K. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Calaga, R. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Capatina, O. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Capelli, T. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Carra, F. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Leuxe, R. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Kuder, N. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Zanoni, C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Li, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Ratti, A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-05-03

    The LHC high luminosity project envisages the use of the crabbing technique for increasing and levelling the LHC luminosity. Double Quarter Wave (DQW) resonators are compact cavities especially designed to meet the technical and performance requirements for LHC beam crabbing. Two DQW crab cavities are under fabrication and will be tested with beam in the Super Proton Synchrotron (SPS) at CERN by 2017. This paper describes the design and prototyping of the DQW crab cavities for the SPS test.

  7. Changeability of Oral Cavity Environment

    OpenAIRE

    Surdacka, Anna; Strzyka?a, Krystyna; Rydzewska, Anna

    2007-01-01

    Objectives In dentistry, the results of in vivo studies on drugs, dental fillings or prostheses are routinely evaluated based on selected oral cavity environment parameters at specific time points. Such evaluation may be confounded by ongoing changes in the oral cavity environment induced by diet, drug use, stress and other factors. The study aimed to confirm oral cavity environment changeability. Methods 24 healthy individuals aged 20?30 had their oral cavity environment prepared by having p...

  8. Cavity quantum electrodynamics with a Rydberg-blocked atomic ensemble

    DEFF Research Database (Denmark)

    Guerlin, Christine; Brion, Etienne; Esslinger, Tilman

    2010-01-01

    The realization of a Jaynes-Cummings model in the optical domain is proposed for an atomic ensemble. The scheme exploits the collective coupling of the atoms to a quantized cavity mode and the nonlinearity introduced by coupling to high-lying Rydberg states. A two-photon transition resonantly...... effective Jaynes-Cummings model. We use numerical simulations to show that the cavity transmission can be used to reveal detailed properties of the Jaynes-Cummings ladder of excited states and that the atomic nonlinearity gives rise to highly nontrivial photon emission from the cavity. Finally, we suggest...... couples the single-atom ground state |g> to a Rydberg state |e>via a nonresonant intermediate state |i>, but due to the interaction between Rydberg atoms only a single atom can be resonantly excited in the ensemble. This restricts the state space of the ensemble to the collective ground state |G...

  9. Optimization of photonic crystal cavities

    DEFF Research Database (Denmark)

    Wang, Fengwen; Sigmund, Ole

    2017-01-01

    We present optimization of photonic crystal cavities. The optimization problem is formulated to maximize the Purcell factor of a photonic crystal cavity. Both topology optimization and air-hole-based shape optimization are utilized for the design process. Numerical results demonstrate...... that the Purcell factor of the photonic crystal cavity can be significantly improved through optimization....

  10. Single-cavity SLED device

    International Nuclear Information System (INIS)

    Lippmann, B.A.

    1984-09-01

    The conventional SLED device used at SLAC requires two cavities. However, the same effect can be obtained with a single cavity; the theory and operation of the device is the same, only the hardware is changed. The single-cavity device is described here

  11. Hollow waveguide cavity ringdown spectroscopy

    Science.gov (United States)

    Dreyer, Chris (Inventor); Mungas, Greg S. (Inventor)

    2012-01-01

    Laser light is confined in a hollow waveguide between two highly reflective mirrors. This waveguide cavity is used to conduct Cavity Ringdown Absorption Spectroscopy of loss mechanisms in the cavity including absorption or scattering by gases, liquid, solids, and/or optical elements.

  12. A Digital Self Excited Loop for Accelerating Cavity Field Control

    International Nuclear Information System (INIS)

    Curt Hovater; Trent Allison; Jean Delayen; John Musson; Tomasz Plawski

    2007-01-01

    We have developed a digital process that emulates an analog oscillator and ultimately a self excited loop (SEL) for field control. The SEL, in its analog form, has been used for many years for accelerating cavity field control. In essence the SEL uses the cavity as a resonant circuit -- much like a resonant (tank) circuit is used to build an oscillator. An oscillating resonant circuit can be forced to oscillate at different, but close, frequencies to resonance by applying a phase shift in the feedback path. This allows the circuit to be phased-locked to a master reference, which is crucial for multiple cavity accelerators. For phase and amplitude control the SEL must be forced to the master reference frequency, and feedback provided for in both dimensions. The novelty of this design is in the way digital signal processing (DSP) is structured to emulate an analog system. While the digital signal processing elements are not new, to our knowledge this is the first time that the digital SEL concept has been designed and demonstrated. This paper reports on the progress of the design and implementation of the digital SEL for field control of superconducting accelerating cavities

  13. Generation of single-frequency tunable green light in a coupled ring tapered diode laser cavity

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Petersen, Paul Michael

    2013-01-01

    in the broad wavelength range from 1049 nm to 1093 nm and the beam propagation factor is improved from M2 = 2.8 to below 1.1. The laser frequency is automatically locked to the cavity resonance frequency using optical feedback. Furthermore, we show that this adaptive external cavity approach leads to efficient...

  14. Numerical Investigation of Vertical Cavity Lasers With High-Contrast Gratings Using the Fourier Modal Method

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza; Mørk, Jesper; Chung, Il-Sug

    2016-01-01

    We explore the use of a modal expansion technique, Fourier modal method (FMM), for investigating the optical properties of vertical cavities employing high-contrast gratings (HCGs). Three techniques for determining the resonance frequency and quality factor (Q-factor) of a cavity mode are compared...

  15. The analytical solution of wake-fields in an elliptical pillbox cavity

    International Nuclear Information System (INIS)

    Yang, J.S.; Chen, K.W.

    1991-01-01

    The wake potential of a bunch of relativistic charged particles traversing an elliptical pillbox cavity is derived analytically in the limit of vanishing aperture. It is found that the resonant modes of an elliptical cavity can be expressed in terms of Mathieu functions. Calculation results are presented and compared with numerical ones. (author) 10 refs., 10 figs., 2 tabs

  16. Imaging diagnosis of the oral cavity; Diagnostico por imagem da cavidade oral

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Ricardo Pires de; Paes Junior, Ademar Jose de Oliveira [Complexo Hospitalar Heliopolis, Sao Paulo, SP (Brazil). Servico de Diagnostico por Imagem]. E-mail: ricapires@ig.com.br; Pagotto, Silvia Regina; Rapoport, Abrao [Complexo Hospitalar Heliopolis, Sao Paulo, SP (Brazil). Curso de Pos-graduacao em Cirurgia de Cabeca e Pescoco; Soares, Aldemir Humberto [Hospital do Servidor Publico Estadual de Sao Paulo, Sao Paulo (Brazil). Servico de Diagnostico por Imagem

    2003-06-01

    Magnetic resonance imaging and computed tomography are important additional methods for the diagnosis of oral cavity diseases. The technical aspects of both methods are discussed including their advantages and limitations. The anatomy of the oral cavity is reviewed as well as some characteristics of squamous cell carcinoma, which is the most frequent neoplasia in this region. (author)

  17. Implementation of intra-cavity beam shaping technique to enhance pump efficiency

    CSIR Research Space (South Africa)

    Litvin, IA

    2012-02-01

    Full Text Available In this work the author proposes an implementation of a new intra-cavity beam shaping technique to vary the intensity distribution of the fundamental mode in a resonator cavity while maintaining a constant intensity distribution at the output...

  18. High-Q cavity-induced fluxon bunching in inductively coupled Josephson junctions

    DEFF Research Database (Denmark)

    Madsen, S.; Grønbech-Jensen, Niels; Pedersen, Niels Falsig

    2008-01-01

    We consider fluxon dynamics in a stack of inductively coupled long Josephson junctions connected capacitively to a common resonant cavity at one of the boundaries. We study, through theoretical and numerical analyses, the possibility for the cavity to induce a transition from the energetically...

  19. Generating and revealing a quantum superposition of electromagnetic-field binomial states in a cavity

    International Nuclear Information System (INIS)

    Lo Franco, R.; Compagno, G.; Messina, A.; Napoli, A.

    2007-01-01

    We introduce the N-photon quantum superposition of two orthogonal generalized binomial states of an electromagnetic field. We then propose, using resonant atom-cavity interactions, nonconditional schemes to generate and reveal such a quantum superposition for the two-photon case in a single-mode high-Q cavity. We finally discuss the implementation of the proposed schemes

  20. Middle ear cavity morphology is consistent with an aquatic origin for testudines.

    Directory of Open Access Journals (Sweden)

    Katie L Willis

    Full Text Available The position of testudines in vertebrate phylogeny is being re-evaluated. At present, testudine morphological and molecular data conflict when reconstructing phylogenetic relationships. Complicating matters, the ecological niche of stem testudines is ambiguous. To understand how turtles have evolved to hear in different environments, we examined middle ear morphology and scaling in most extant families, as well as some extinct species, using 3-dimensional reconstructions from micro magnetic resonance (MR and submillimeter computed tomography (CT scans. All families of testudines exhibited a similar shape of the bony structure of the middle ear cavity, with the tympanic disk located on the rostrolateral edge of the cavity. Sea Turtles have additional soft tissue that fills the middle ear cavity to varying degrees. When the middle ear cavity is modeled as an air-filled sphere of the same volume resonating in an underwater sound field, the calculated resonances for the volumes of the middle ear cavities largely fell within testudine hearing ranges. Although there were some differences in morphology, there were no statistically significant differences in the scaling of the volume of the bony middle ear cavity with head size among groups when categorized by phylogeny and ecology. Because the cavity is predicted to resonate underwater within the testudine hearing range, the data support the hypothesis of an aquatic origin for testudines, and function of the middle ear cavity in underwater sound detection.

  1. Colloquium: cavity optomechanics

    CERN Multimedia

    2011-01-01

    Monday 14 November 2011, 17:00 Ecole de Physique, Auditoire Stueckelberg Université de Genève Cavity optomechanics: controlling micro mechanical oscillators with laser light Prof. Tobias Kippenberg EPFL, Lausanne Laser light can be used to cool and to control trapped ions, atoms and molecules at the quantum level. This has lead to spectacular advances such as the most precise atomic clocks. An outstanding frontier is the control with lasers of nano- and micro-mechancial systems. Recent advances in cavity optomechanics have allowed such elementary control for the first time, enabling mechanical systems to be ground state cooled leading to readout with quantum limited sensitivity and permitting to explore new device concepts resulting from radiation pressure.  

  2. Beyond strong coupling in a massively multimode cavity

    Science.gov (United States)

    Sundaresan, Neereja; Liu, Yanbing; Sadri, Darius; Szocs, Laszlo; Underwood, Devin; Malekakhlagh, Moein; Tureci, Hakan; Houck, Andrew

    2015-03-01

    We present experiments in a new regime of cavity quantum electrodynamics (cQED), the multimode strong coupling regime, in which the qubit-cavity coupling is comparable to the free spectral range, thus requiring the collective treatment of all modes along with the qubit. Here we show that this regime is accessible in circuit QED by coupling a 90MHz microwave cavity with a transmon qubit, resonant with the 75th harmonic with a coupling strength exceeding 30MHz. When driving this system, we observe multimode fluorescence consistent with cavity-enhanced sideband emission, with unexpected multi-photon processes and the emergence of ultra-narrow linewidths. This multimode coupling opens the door for a wide range of potential experiments, including studying the manifestation of complex many-body phenomena, the breakdown of the rotating wave approximation, and the bridge between discrete and continuous Hilbert spaces.

  3. High bandwidth frequency lock of a rigid tunable optical cavity.

    Science.gov (United States)

    Millo, Jacques; Merzougui, Mourad; Di Pace, Sibilla; Chaibi, Walid

    2014-11-10

    In this paper, we present a high bandwidth frequency lock of a rigid tunable Fabry Perot cavity based on a set of lead zirconate titanate (PZT) actuators. The cavity spacer was specifically designed such that the frequency of the first resonance of the whole assembly under PZT excitation is above 35 kHz, thus allowing a servo-loop bandwidth of 13 kHz. It is demonstrated that no significant noise is added by the cavity to the output beam with respect to the input beam over the servo-loop bandwidth. This cavity can be used as a pre-mode cleaner in interferometric gravitational wave detectors such as the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo.

  4. Transverse Field Perturbation For PIP-II SRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Berrutti, Paolo [Fermilab; Khabiboulline, Timergali N. [Fermilab; Lebedev, Valeri [Fermilab; Yakovlev, Vyacheslav P. [Fermilab

    2015-06-01

    Proton Improvement Plan II (PIP-II) consists in a plan for upgrading the Fermilab proton accelerator complex to a beam power capability of at least 1 MW delivered to the neutrino production target. A room temperature section accelerates H⁻ ions to 2.1 MeV and creates the desired bunch structure for injection into the superconducting (SC) linac. Five cavity types, operating at three different frequencies 162.5, 325 and 650 MHz, provide acceleration to 800 MeV. This paper presents the studies on transverse field perturbation on particle dynamic for all the superconducting cavities in the linac. The effects studied include quadrupole defocusing for coaxial resonators, and dipole kick due to couplers for elliptical cavities. A multipole expansion has been performed for each of the cavity designs including effects up to octupole.

  5. Field stabilization in superconducting cavities under pulsed operating

    International Nuclear Information System (INIS)

    Tessier, J.M.

    1996-01-01

    Within the framework of Tesla linear accelerator project, superconducting cavity battery is used to accelerate electrons and positrons. These cavities require pulsed running and must reach very high accelerating gradients. Under the action of the Lorentz force, the resonance frequency shifts and leaves the band-pass width, which hinders the field from taking its maximal value inside the cavity. The setting of an auto-oscillating loop allows to bring the generator frequency under the control of the cavity frequency. A feedback system is needed to reduce the energy dispersion inside the particle packets. The effects of the mechanical vibrations that disturb the accelerating voltage phase between two impulses are also compensated by a feedback loop. This thesis describes all these phenomena and computes their effects on the energy dispersion of the beam in both cases of relativistic and non-relativistic particles. (A.C.)

  6. Controllable coupling of distributed qubits within a microtoroidal cavity network

    Science.gov (United States)

    Hu, C.; Xia, Y.; Song, J.

    2012-05-01

    We propose a scheme to control the coupling between two arbitrary atoms scattered within a quantum network composed of microtoroidal cavities linked by a ring-fibre. The atom-atom effective couplings are induced by pairing of off-resonant Raman transitions. The couplings can be arbitrarily controlled by adjusting classical fields. Compared with the previous scheme [S.B. Zheng, C.P. Yang, F. Nori, Phys. Rev. A 82, 042327 (2010)], the present scheme uses microtoroidal cavities with higher coupling efficiency than Fabry-Perot cavities. Furthermore, the scheme is not only suitable for the short-fibre limit, but also for multiple fibre modes. The added fibre modes can play a positive role, especially when the coupling rate between cavity-mode and fibre-mode is not large. In addition, a wider frequency domain of fibre modes can be used in this scheme.

  7. Comparison of Different Numerical Methods for Quality Factor Calculation of Nano and Micro Photonic Cavities

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza; Mørk, Jesper; Chung, Il-Sug

    2014-01-01

    Four different numerical methods for calculating the quality factor and resonance wavelength of a nano or micro photonic cavity are compared. Good agreement was found for a wide range of quality factors. Advantages and limitations of the different methods are discussed.......Four different numerical methods for calculating the quality factor and resonance wavelength of a nano or micro photonic cavity are compared. Good agreement was found for a wide range of quality factors. Advantages and limitations of the different methods are discussed....

  8. Sensitive Detection of Individual Neutral Atoms in a Strong Coupling Cavity QED System

    International Nuclear Information System (INIS)

    Zhang Peng-Fei; Zhang Yu-Chi; Li Gang; Du Jin-Jin; Zhang Yan-Feng; Guo Yan-Qiang; Wang Jun-Min; Zhang Tian-Cai; Li Wei-Dong

    2011-01-01

    We experimentally demonstrate real-time detection of individual cesium atoms by using a high-finesse optical micro-cavity in a strong coupling regime. A cloud of cesium atoms is trapped in a magneto-optical trap positioned at 5 mm above the micro-cavity center. The atoms fall down freely in gravitation after shutting off the magneto-optical trap and pass through the cavity. The cavity transmission is strongly affected by the atoms in the cavity, which enables the micro-cavity to sense the atoms individually. We detect the single atom transits either in the resonance or various detunings. The single atom vacuum-Rabi splitting is directly measured to be Ω = 2π × 23.9 MHz. The average duration of atom-cavity coupling of about 110 μs is obtained according to the probability distribution of the atom transits. (fundamental areas of phenomenology(including applications))

  9. Development and application of 3D RF cavity code MAFIA

    International Nuclear Information System (INIS)

    Gao Tieta

    1992-01-01

    The design of a asymmetric RF cavity requires a code that can treat 3D structure. This paper describes the characteristics, functions and applications of the 3D RF cavity computer-aided design (CAD) program MAFIA. The 3D geometry design of non-axial symmetric RF cavity with a coupler is realized by CAD method. A kind of data input is presented that can save not only machine memory, but also the CPU time, and large programs can be run on a medium-small size machine. The numerical simulation of a L-band RF cavity is presented and the modeling results agree well with its experimental values. We have also compared electric properties of the RF cavity with variant geometry by applying 3D numerical and graphic simulations. The influence on electric and magnetic fields by adding a input coupler or HOM coupler at the side of a RF cavity is analysed. Adding a coupler to a RF cavity can cause the change of resonance frequency. A method that can compensate the variation of frequency is also presented

  10. Cavity RF mode analysis using a boundary-integral method

    International Nuclear Information System (INIS)

    Jong, M.S. de; Adams, F.P.

    1993-01-01

    A 3-dimensional boundary-integral method has been developed for rf cavity mode analysis. A frequency-dependent, homogeneous linear matrix equation is generated from a variant of the magnetic field integral equation (MFIE) where the domain of integration is a closed surface specifying the rf envelope of the cavity. Frequencies at which the MFIE has non-zero solutions are mode frequencies of the cavity, and the solutions are the corresponding surface magnetic field distributions. The MFIE can then be used to calculate the electric and magnetic field at any other point inside the cavity. Forward iteration is used to find the largest complex eigenvalue of the matrix at a specific frequency. This eigenvalue is 1 when the frequency corresponds to a cavity rf resonance. The matrix equivalent of the MFIE is produced by approximating the cavity surface by a set of perfectly conducting surface elements, and assuming that the surface magnetic field has constant amplitude on each element. The method can handle cavities with complex symmetries, and be easily integrated with finite-element heat-transfer and stress analysis codes

  11. Resonant freak microwaves

    International Nuclear Information System (INIS)

    Aguiar, F.M. de

    2011-01-01

    The Helmholtz equation describing transverse magnetic modes in a closed flat microwave resonator with 60 randomly distributed discs is numerically solved. At lower frequencies, the calculated wave intensity spatially distributed obeys the universal Porter-Thomas form if localized modes are excluded. A superposition of resonant modes is shown to lead to rare events of extreme intensities (freak waves) at localized 'hot spots'. The temporally distributed intensity of such a superposition at the center of a hot spot also follows the Porter-Thomas form. Branched modes are found at higher frequencies. The results bear resemblance to recent experiments reported in an open cavity.

  12. Q-factor of optical delay-line based cavities and oscillators

    Science.gov (United States)

    Hosseini, S. Esmail; Karimi, Azadeh; Jahanbakht, Sajad

    2018-01-01

    In this paper a theoretical derivation of unloaded and loaded Q-factor of delay-line cavities, such as optical fiber delay-lines, and delay-line based oscillators, such as optoelectronic oscillators (OEOs), is presented based on three approaches: (I) second-order resonator approximation, (II) linear time-invariant phase-space model and (III) energy approach. Theoretical expressions for unloaded and loaded Q-factor of delay-line based cavities and oscillators are derived. We show that the Q-factor of a delay-line based cavity is a function of its round-trip time that is not equal to the energy decay-time of usual microwave or optical resonators. Hence, the behavior of the Q-factor of a delay-line based cavity will not be the same as that of the usual resonators. We show that the loaded Q-factor of a delay-line cavity is greater than its unloaded Q-factor!, besides we show that the Q-factor of a lossy delay-line cavity is the same as that of the lossless one! (in contrast to the behavior of the usual resonators). We also show that the Q-factor of a delay-line based oscillator is proportional to the half of the round-trip time of its delay line while the Q-factor of an oscillator based on a usual resonator is proportional to the energy decay time of its resonator.

  13. Miniature Cavity-Enhanced Diamond Magnetometer

    Science.gov (United States)

    Chatzidrosos, Georgios; Wickenbrock, Arne; Bougas, Lykourgos; Leefer, Nathan; Wu, Teng; Jensen, Kasper; Dumeige, Yannick; Budker, Dmitry

    2017-10-01

    We present a highly sensitive miniaturized cavity-enhanced room-temperature magnetic-field sensor based on nitrogen-vacancy centers in diamond. The magnetic resonance signal is detected by probing absorption on the 1042-nm spin-singlet transition. To improve the absorptive signal the diamond is placed in an optical resonator. The device has a magnetic-field sensitivity of 28 pT /√{Hz } , a projected photon shot-noise-limited sensitivity of 22 pT /√{Hz } , and an estimated quantum projection-noise-limited sensitivity of 0.43 pT /√{Hz } with the sensing volume of ˜390 μ m ×4500 μ m2 . The presented miniaturized device is the basis for an endoscopic magnetic-field sensor for biomedical applications.

  14. Optical Microspherical Resonators for Biomedical Sensing

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2011-01-01

    Full Text Available Optical resonators play an ubiquitous role in modern optics. A particular class of optical resonators is constituted by spherical dielectric structures, where optical rays are total internal reflected. Due to minimal reflection losses and to potentially very low material absorption, these guided modes, known as whispering gallery modes, can confer the resonator an exceptionally high quality factor Q, leading to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. These attractive characteristics make these miniaturized optical resonators especially suited as laser cavities and resonant filters, but also as very sensitive sensors. First, a brief analysis is presented of the characteristics of microspherical resonators, of their fabrication methods, and of the light coupling techniques. Then, we attempt to overview some of the recent advances in the development of microspherical biosensors, underlining a number of important applications in the biomedical field.

  15. Single atoms on demand for cavity QED experiments

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, I.

    2007-09-06

    Cavity quantum electrodynamics (cavity QED) describes electromagnetic fields in a confined space and the radiative properties of atoms in such fields. The simplest example of such system is a single atom interacting with one mode of a high-finesse resonator. Besides observation and exploration of fundamental quantum mechanical effects, this system bears a high potential for applications quantum information science such as, e.g., quantum logic gates, quantum communication and quantum teleportation. In this thesis I present an experiment on the deterministic coupling of a single neutral atom to the mode of a high-finesse optical resonator. In Chapter 1 I describe our basic techniques for trapping and observing single cesium atoms. As a source of single atoms we use a high-gradient magneto-optical trap, which captures the atoms from background gas in a vacuum chamber and cools them down to millikelvin temperatures. The atoms are then transferred without loss into a standing-wave dipole trap, which provides a conservative potential required for experiments on atomic coherence such as quantum information processing and metrology on trapped atoms. Moreover, shifting the standing-wave pattern allows us to deterministically transport the atoms (Chapter 2). In combination with nondestructive fluorescence imaging of individual trapped atoms, this enables us to control their position with submicrometer precision over several millimeters along the dipole trap. The cavity QED system can distinctly display quantum behaviour in the so-called strong coupling regime, i.e., when the coherent atom-cavity coupling rate dominates dissipation in the system. This sets the main requirements on the resonator's properties: small mode volume and high finesse. Chapter 3 is devoted to the manufacturing, assembling, and testing of an ultra-high finesse optical Fabry-Perot resonator, stabilized to the atomic transition. In Chapter 4 I present the transportation of single atoms into the

  16. Single atoms on demand for cavity QED experiments

    International Nuclear Information System (INIS)

    Dotsenko, I.

    2007-01-01

    Cavity quantum electrodynamics (cavity QED) describes electromagnetic fields in a confined space and the radiative properties of atoms in such fields. The simplest example of such system is a single atom interacting with one mode of a high-finesse resonator. Besides observation and exploration of fundamental quantum mechanical effects, this system bears a high potential for applications quantum information science such as, e.g., quantum logic gates, quantum communication and quantum teleportation. In this thesis I present an experiment on the deterministic coupling of a single neutral atom to the mode of a high-finesse optical resonator. In Chapter 1 I describe our basic techniques for trapping and observing single cesium atoms. As a source of single atoms we use a high-gradient magneto-optical trap, which captures the atoms from background gas in a vacuum chamber and cools them down to millikelvin temperatures. The atoms are then transferred without loss into a standing-wave dipole trap, which provides a conservative potential required for experiments on atomic coherence such as quantum information processing and metrology on trapped atoms. Moreover, shifting the standing-wave pattern allows us to deterministically transport the atoms (Chapter 2). In combination with nondestructive fluorescence imaging of individual trapped atoms, this enables us to control their position with submicrometer precision over several millimeters along the dipole trap. The cavity QED system can distinctly display quantum behaviour in the so-called strong coupling regime, i.e., when the coherent atom-cavity coupling rate dominates dissipation in the system. This sets the main requirements on the resonator's properties: small mode volume and high finesse. Chapter 3 is devoted to the manufacturing, assembling, and testing of an ultra-high finesse optical Fabry-Perot resonator, stabilized to the atomic transition. In Chapter 4 I present the transportation of single atoms into the cavity

  17. ISR RF cavities

    CERN Multimedia

    1983-01-01

    In each ISR ring the radiofrequency cavities were installed in one 9 m long straight section. The RF system of the ISR had the main purpose to stack buckets of particles (most of the time protons)coming from the CPS and also to accelerate the stacked beam. The installed RF power per ring was 18 kW giving a peak accelerating voltage of 20 kV. The system had a very fine regulation feature allowing to lower the voltage down to 75 V in a smooth and well controlled fashion.

  18. Digital Measurement System for the HIE-Isolde Superconducting Accelerating Cavities

    CERN Document Server

    Elias, Michal

    Extensive R&D efforts are being invested at CERN into the fundamental science of the RF superconductivity, cavity design, niobium sputtering, coating and RF properties of superconducting cavities. Fast and precise characterization and measurements of RF parameters of the newly produced cavities is essential for advances with the cavity production. The currently deployed analogue measurement system based on an analogue phase discriminators and tracking RF generators is not optimal for efficient work at the SM18 superconducting cavity test stand. If exact properties of the cavity under test are not known a traditional feedback loop will not be able to find resonant frequency in a reasonable time or even at all. This is mainly due to a very high Q factor. The resonance peak is very narrow (fraction of a Hz at 100 MHz). If the resonant frequency is off by several bandwidths, small changes of the cavity field during the tuning will not be measureable. Also cavity field will react only very slowly to any change...

  19. Oral cavity eumycetoma

    Directory of Open Access Journals (Sweden)

    Gisele Alborghetti Nai

    2011-06-01

    Full Text Available Mycetoma is a pathological process in which eumycotic (fungal or actinomycotic causative agents from exogenous source produce grains. It is a localized chronic and deforming infectious disease of subcutaneous tissue, skin and bones. We report the first case of eumycetoma of the oral cavity in world literature. CASE REPORT: A 43-year-old male patient, complaining of swelling and fistula in the hard palate. On examination, swelling of the anterior and middle hard palate, with fistula draining a dark liquid was observed. The panoramic radiograph showed extensive radiolucent area involving the region of teeth 21-26 and the computerized tomography showed communication with the nasal cavity, suggesting the diagnosis of periapical cyst. Surgery was performed to remove the lesion. Histopathological examination revealed purulent material with characteristic grain. Gram staining for bacteria was negative and Grocott-Gomori staining for the detection of fungi was positive, concluding the diagnosis of eumycetoma. The patient was treated with ketoconazole for nine months, and was considered cured at the end of treatment. CONCLUSION: Histopathological examination, using histochemical staining, and direct microscopic grains examination can provide the distinction between eumycetoma and actinomycetoma accurately.

  20. Design and construction of drift tube linac cavities for RIKEN RI Beam Factory

    Science.gov (United States)

    Suda, K.; Sakamoto, N.; Yamada, K.; Arai, S.; Chiba, Y.; Kase, M.; Okuno, H.; Watanabe, Y.; Kamigaito, O.

    2013-09-01

    A new injector linac "RILAC2", has recently been constructed at the RIKEN RI Beam Factory. The main part of the RILAC2 is a drift tube linac that consists of three newly designed cavities. These cavities operate in continuous wave (CW) mode at a fixed frequency of 36.5 MHz. Their structure is based on a quarter-wavelength resonator because this is the smallest resonator available in this frequency range among the available structures. We adopted the direct coupling method in the construction of these cavities. A power amplifier was directly coupled to the cavity without a long transmission line to reduce the installation area and simultaneously reduce construction cost. A detailed cavity and coupler design was carried out via simulation. Our work also describes the design process using three-dimensional electromagnetic simulation software. Construction and operation tests are also shown.

  1. Model for resonant plasma probe.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Johnson, William Arthur; Hebner, Gregory Albert; Jorgenson, Roy E.; Coats, Rebecca Sue

    2007-04-01

    This report constructs simple circuit models for a hairpin shaped resonant plasma probe. Effects of the plasma sheath region surrounding the wires making up the probe are determined. Electromagnetic simulations of the probe are compared to the circuit model results. The perturbing effects of the disc cavity in which the probe operates are also found.

  2. Development of an advanced electropolishing setup for multicell high gradient niobium cavities

    Science.gov (United States)

    Éozénou, F.; Chel, S.; Gasser, Y.; Servouin, C.; Visentin, B.; Charrier, J.-P.; Wang, Z.

    2012-08-01

    Reproducible operation at high performances of superconducting cavities is required for linear accelerators. High beta elliptical cavities are thus of concern and, to achieve required performances for such resonators, surface preparation including electropolishing is recommended. We have designed and operate a setup for electropolishing in the vertical position of multicell cavities in order to: (i) obtain high yield with large elliptical cavities for Superconducting Linac (SPL) or European Spallation Source projects; (ii) develop a reference installation demonstrating that this process is appropriate for the large scale treatment of cavities in industry. The setup described here is the first one able to electropolish vertically multicell cavities with circulating acid and high safety standards. This equipment makes it possible to use a wide range of parameters such as voltage, acid flow rate, temperature, and nitrogen injection with an R&D purpose in mind. Optimization is studied using modeling with COMSOL software for different cavities. As examples, we present some results for the 704 MHz high-beta SPL cavity and the 1300 MHz International Linear Collider cavity and show the influence of cathode shape on both acid flow and electric field distribution during the process. Importance of the size of the cavity and first results achieved on single-cell and nine-cell cavities will be discussed.

  3. Development of an advanced electropolishing setup for multicell high gradient niobium cavities

    Directory of Open Access Journals (Sweden)

    F. Éozénou

    2012-08-01

    Full Text Available Reproducible operation at high performances of superconducting cavities is required for linear accelerators. High beta elliptical cavities are thus of concern and, to achieve required performances for such resonators, surface preparation including electropolishing is recommended. We have designed and operate a setup for electropolishing in the vertical position of multicell cavities in order to: (i obtain high yield with large elliptical cavities for Superconducting Linac (SPL or European Spallation Source projects; (ii develop a reference installation demonstrating that this process is appropriate for the large scale treatment of cavities in industry. The setup described here is the first one able to electropolish vertically multicell cavities with circulating acid and high safety standards. This equipment makes it possible to use a wide range of parameters such as voltage, acid flow rate, temperature, and nitrogen injection with an R&D purpose in mind. Optimization is studied using modeling with COMSOL software for different cavities. As examples, we present some results for the 704 MHz high-beta SPL cavity and the 1300 MHz International Linear Collider cavity and show the influence of cathode shape on both acid flow and electric field distribution during the process. Importance of the size of the cavity and first results achieved on single-cell and nine-cell cavities will be discussed.

  4. RF Characterization of Niobium Films for Superconducting Cavities

    CERN Document Server

    Aull† , S; Doebert, S; Junginger, T; Ehiasarian, AP; Knobloch, J; Terenziani, G

    2013-01-01

    The surface resistance RS of superconductors shows a complex dependence on the external parameters such as temperature, frequency or radio-frequency (RF) field. The Quadrupole Resonator modes of 400, 800 and 1200 MHz allow measurements at actual operating frequencies of superconducting cavities. Niobium films on copper substrates have several advantages over bulk niobium cavities. HIPIMS (High-power impulse magnetron sputtering) is a promising technique to increase the quality and therefore the performance of niobium films. This contribution will introduce CERNs recently developed HIPIMS coating apparatus. Moreover, first results of niobium coated copper samples will be presented, revealing the dominant loss mechanisms.

  5. Coupling to fast MHD eigenmodes in a toroidal cavity

    International Nuclear Information System (INIS)

    Paoloni, F.J.

    1975-05-01

    The coupling to fast MHD waves in toroidal-like geometry is calculated when eigenmodes exist in the plasma. The torus is considered to be a resonant cavity into which energy is coupled by a half turn loop. The cavity Q is calculated for the minority heating process, for cyclotron harmonic damping, electron transit-time magnetic pumping, wall loading, and Coulomb collisional damping. The problem of sustaining the eigenmode as the plasma conditions change with time is also discussed. One method that seems to be practical is a feedback scheme that varies the plasma major radius by a small amount as the conditions change. (U.S.)

  6. An RF input coupler for a superconducting single cell cavity

    International Nuclear Information System (INIS)

    Fechner, B.; Ouchi, Nobuo; Kusano, Joichi; Mizumoto, Motoharu; Mukugi, Ken; Krawczyk, F.

    1999-03-01

    Japan Atomic Energy Research Institute proposes a high intensity proton accelerator for the Neutron Science Project. A superconducting linac is a main option for the high energy part of the accelerator. Design and development work for the superconducting accelerating cavities (resonant frequency of 600 MHz) is in progress. Superconducting cavities have an advantage of very high accelerating efficiency because RF wall loss is very small and much of the RF power fed to the cavity is consumed for the beam acceleration. On the other hand, an RF input coupler for the superconducting cavity has to be matched to the beam loading. Therefore, estimation of coupling coefficient or external quality factor (Qext) of the RF input coupler is important for the design of the couplers. In this work, Qext's were calculated by the electromagnetic analysis code (MAFIA) and were compared with those by the measurements. A β (ratio of the particle velocity to the light velocity) = 0.5 single-cell cavity with either axial coupler or side coupler was used in this work. In the experiments, a model cavity made by copper is applied. Both 2- and 3-dimensional calculations were performed in the axial coupler geometry and the results were compared. The agreements between calculated and measured values are good and this method for calculation of Qext is confirmed to be proper for the design of the RF input couplers. (author)

  7. Determination of the dipole moment of OCS with a microwave absorption cavity

    NARCIS (Netherlands)

    Dijkerman, H.A.; Ruitenberg, G.

    The electric dipole moment of OCS has been measured with a resonance cavity as a Stark absorption cell. The result: μOCS = 0.7149 ± 0.0003. Debye agrees well with the dipole moment data obtained with an electric resonance beam experiment.

  8. MEDICI reactor cavity model

    International Nuclear Information System (INIS)

    Bergeron, K.D.; Trebilcock, W.

    1983-01-01

    The MEDICI reactor cavity model is currently under development with the goal of providing a flexible, relatively realistic treatment of ex-vessel severe accident phenomena suitable for large-system codes like CONTAIN and MELCOR. The code is being developed with an emphasis on top-down design, to facilitate adaptability and multiple applications. A brief description of the overall code structure is provided. One of the key new models is then described in more detail. This is a dynamic quench model for debris beds. An example calculation using this model is presented. The question of whether it is necessary to consider the simultaneous motion of the quench front and ablation of the concrete is addressed with some scoping models

  9. Resonant interaction modified by the atomic environment

    International Nuclear Information System (INIS)

    Sainz, I; Klimov, A B; Chumakov, S M

    2003-01-01

    The dynamics of a resonant atom interacting with a quantum cavity field in the presence of many off-resonant atoms is studied. In the framework of the effective Hamiltonian approach we show that the results of elimination of non-resonant transitions are (a) a dynamical Stark shift of the field frequency, dependent on the populations of non-resonant atoms, (b) dependence of the coupling constant between the resonant atom and the field on the populations of non-resonant atoms, and (c) an effective dipole-dipole interaction between non-resonant atoms. Two effects (the coherent influence and dephasing) of the off-resonant environment on the dynamics of the resonant atom are discussed

  10. Superconducting cavity model for LEP

    CERN Document Server

    CERN PhotoLab

    1979-01-01

    A superconducting cavity model is being prepared for testing in a vertical cryostat.At the top of the assembly jig is H.Preis while A.Scharding adjusts some diagnostic equipment to the cavity. See also photo 7912501X.

  11. Superconducting Storage Cavity for RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi,I.

    2009-01-02

    This document provides a top-level description of a superconducting cavity designed to store hadron beams in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It refers to more detailed documents covering the various issues in designing, constructing and operating this cavity. The superconducting storage cavity is designed to operate at a harmonic of the bunch frequency of RHIC at a relatively low frequency of 56 MHz. The current storage cavities of RHIC operate at 197 MHz and are normal-conducting. The use of a superconducting cavity allows for a high gap voltage, over 2 MV. The combination of a high voltage and low frequency provides various advantages stemming from the resulting large longitudinal acceptance bucket.

  12. Changeability of oral cavity environment.

    Science.gov (United States)

    Surdacka, Anna; Strzyka A, Krystyna; Rydzewska, Anna

    2007-01-01

    In dentistry, the results of in vivo studies on drugs, dental fillings or prostheses are routinely evaluated based on selected oral cavity environment parameters at specific time points. Such evaluation may be confounded by ongoing changes in the oral cavity environment induced by diet, drug use, stress and other factors. The study aimed to confirm oral cavity environment changeability. 24 healthy individuals aged 20-30 had their oral cavity environment prepared by having professional hygiene procedures performed and caries lesions filled. Baseline examination and the examination two years afterwards, evaluated clinical and laboratory parameters of oral cavity environment. Caries incidence was determined based on DMFT and DMFS values, oral cavity hygiene on Plaque Index (acc. Silness & Loe) and Hygiene Index (acc. O'Leary), and the gingival status on Gingival Index (acc. Loe & Silness) and Gingival Bleeding Index (acc. Ainamo & Bay). Saliva osmolarity, pH and concentrations of Ca(2+), Pi, Na(+), Cl(-), total protein, albumins, F(-) and Sr(2+) were determined. The results confirmed ongoing changeability of the oral cavity environment. After 2 years of the study reduction in oral cavity hygiene parameters PLI and HI (P<0.1), and gingival indices as well as lower saliva concentration of Ca(2+) (P<.001), Pi (P<.06), K(+) (P<.04), Sr(2+) (P<.03), Na(+) (P<.1), against the baseline values, were observed. Total protein and albumin saliva concentrations were also significantly lower. Physiological oral cavity environment is subject to constant, individually different, changes which should be considered when analysing studies that employ oral cavity environment parameters.

  13. Beam Fields in an Integrated Cavity, Coupler and Window Configuration

    Energy Technology Data Exchange (ETDEWEB)

    Weathersby, Stephen; Novokhatski, Alexander; /SLAC

    2010-02-10

    In a multi-bunch high current storage ring, beam generated fields couple strongly into the RF cavity coupler structure when beam arrival times are in resonance with cavity fields. In this study the integrated effect of beam fields over several thousand RF periods is simulated for the complete cavity, coupler, window and waveguide system of the PEP-II B-factory storage ring collider. We show that the beam generated fields at frequencies corresponding to several bunch spacings for this case gives rise to high field strength near the ceramic window which could limit the performance of future high current storage rings such as PEP-X or Super B-factories.

  14. Higher order mode damping in Kaon factory RF cavities

    International Nuclear Information System (INIS)

    Enegren, T.; Poirier, R.; Griffin, J.; Walling, L.; Thiessen, H.A.; Smythe, W.R.

    1989-05-01

    Proposed designs for Kaon factory accelerators require that the rf cavities support beam currents on the order of several amperes. The beam current has Fourier components at all multiples of the rf frequency. Empty rf buckets produce additional components at all multiples of the revolution frequency. If a Fourier component of the beam coincides with the resonant frequency of a higher order mode of the cavity, which is inevitable if the cavity has a large frequency swing, significant excitation of this mode can occur. The induced voltage may then excite coupled bunch mode instabilities. Effective means are required to damp higher order modes without significantly affecting the fundamental mode. A mode damping scheme based on coupled transmission lines has been investigated and is report

  15. Slot-coupled CW standing wave accelerating cavity

    Science.gov (United States)

    Wang, Shaoheng; Rimmer, Robert; Wang, Haipeng

    2017-05-16

    A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

  16. Rf transfer in the Coupled-Cavity Free-Electron Laser Two-Beam Accelerator

    International Nuclear Information System (INIS)

    Makowski, M.A.

    1991-01-01

    A significant technical problem associated with the Coupled-Cavity Free-Electron Laser Two-Beam Accelerator is the transfer of RF energy from the drive accelerator to the high-gradient accelerator. Several concepts have been advanced to solve this problem. This paper examines one possible solution in which the drive and high-gradient cavities are directly coupled to one another by means of holes in the cavity walls or coupled indirectly through a third intermediate transfer cavity. Energy cascades through the cavities on a beat frequency time scale which must be made small compared to the cavity skin time but large compared to the FEL pulse length. The transfer is complicated by the fact that each of the cavities in the system can support many resonant modes near the chosen frequency of operation. A generalized set of coupled-cavity equations has been developed to model the energy transfer between the various modes in each of the cavities. For a two cavity case transfer efficiencies in excess of 95% can be achieved. 3 refs., 2 figs

  17. Output field-quadrature measurements and squeezing in ultrastrong cavity-QED

    Science.gov (United States)

    Stassi, Roberto; Savasta, Salvatore; Garziano, Luigi; Spagnolo, Bernardo; Nori, Franco

    2016-12-01

    We study the squeezing of output quadratures of an electro-magnetic field escaping from a resonator coupled to a general quantum system with arbitrary interaction strengths. The generalized theoretical analysis of output squeezing proposed here is valid for all the interaction regimes of cavity-quantum electrodynamics: from the weak to the strong, ultrastrong, and deep coupling regimes. For coupling rates comparable or larger then the cavity resonance frequency, the standard input-output theory for optical cavities fails to calculate the variance of output field-quadratures and predicts a non-negligible amount of output squeezing, even if the system is in its ground state. Here we show that, for arbitrary interaction strength and for general cavity-embedded quantum systems, no squeezing can be found in the output-field quadratures if the system is in its ground state. We also apply the proposed theoretical approach to study the output squeezing produced by: (i) an artificial two-level atom embedded in a coherently-excited cavity; and (ii) a cascade-type three-level system interacting with a cavity field mode. In the latter case the output squeezing arises from the virtual photons of the atom-cavity dressed states. This work extends the possibility of predicting and analyzing the results of continuous-variable optical quantum-state tomography when optical resonators interact very strongly with other quantum systems.

  18. Nonlocal Intracranial Cavity Extraction

    Science.gov (United States)

    Manjón, José V.; Eskildsen, Simon F.; Coupé, Pierrick; Romero, José E.; Collins, D. Louis; Robles, Montserrat

    2014-01-01

    Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV) is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden. PMID:25328511

  19. Nonlocal Intracranial Cavity Extraction

    Directory of Open Access Journals (Sweden)

    José V. Manjón

    2014-01-01

    Full Text Available Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden.

  20. Frequency-feedback cavity enhanced spectrometer

    Science.gov (United States)

    Hovde, David Christian; Gomez, Anthony

    2015-08-18

    A spectrometer comprising an optical cavity, a light source capable of producing light at one or more wavelengths transmitted by the cavity and with the light directed at the cavity, a detector and optics positioned to collect light transmitted by the cavity, feedback electronics causing oscillation of amplitude of the optical signal on the detector at a frequency that depends on cavity losses, and a sensor measuring the oscillation frequency to determine the cavity losses.

  1. Cavity solitons in a microring dimer with gain and loss

    Science.gov (United States)

    Milián, Carles; Kartashov, Yaroslav V.; Skryabin, Dmitry V.; Torner, Lluis

    2018-03-01

    We address a pair of vertically coupled microring resonators with gain and loss pumped by a single-frequency field. Coupling between microrings results in a twofold splitting of the single microring resonance that increases when gain and losses decrease and that gives rise to two different cavity soliton (CS) families. We show that the existence regions of CSs are tunable and that both CS families can be stable in the presence of an imbalance between gain and losses in the two microrings. These findings enable experimental realization of frequency combs in configurations with active microrings and contribute towards the realization of compact multisoliton comb sources.

  2. Entanglement Evolution of Jaynes-Cummings Model in Resonance Case and Non-resonance Case

    Science.gov (United States)

    Cheng, Jing; Chen, Xi; Shan, Chuan-Jia

    2018-03-01

    We investigate the entanglement evolution of a two-level atom and a quantized single model electromagnetic filed in the resonance and non-resonance cases. The effects of the initial state, detuning degree, photon number on the entanglement are shown in detail. The results show that the atom-cavity entanglement state appears with periodicity. The increasing of the photon number can make the period of quantum entanglement be shorter. In the non-resonant case, if we choose the suitable initial state the entanglement of atom-cavity can be 1.0

  3. Analysis of a four-mirror-cavity enhanced Michelson interferometer.

    Science.gov (United States)

    Thüring, André; Lück, Harald; Danzmann, Karsten

    2005-12-01

    We investigate the shot-noise-limited sensitivity of a four-mirror-cavity enhanced Michelson interferometer. The intention of this interferometer topology is the reduction of thermal lensing and the impact of the interferometers contrast although transmissive optics are used with high circulating powers. The analytical expressions describing the light fields and the frequency response are derived. Although the parameter space has 11 dimensions, a detailed analysis of the resonance feature gives boundary conditions allowing systematic parameter studies.

  4. Resonance Control for Future Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Schappert, Warren [Fermilab

    2017-05-01

    Many of the next generation of particle accelerators (LCLS II, PIP II) are designed for relatively low beam loading. Low beam loading requirement means the cavities can operate with narrow bandwidths, minimizing capital and base operational costs of the RF power system. With such narrow bandwidths, however, cavity detuning from microphonics or dynamic Lorentz Force Detuning becomes a significant factor, and in some cases can significantly increase both the acquisition cost and the operational cost of the machine. In addition to the efforts to passive environmental detuning reduction (microphonics) active resonance control for the SRF cavities for next generation linear machine will be required. State of the art in the field of the SRF Cavity active resonance control and the results from the recent efforts at FNAL will be presented in this talk.

  5. Cold test of cylindrical open resonator for 42 GHz, 200 kW gyrotron

    Indian Academy of Sciences (India)

    3Centre for Research in Microwave Tubes (CRMT), Banaras Hindu University,. Varanasi 221 005, India e-mail: ... The up and down taper of the cavity provide enough reflection to maintain a standing wave field in the cavity. Reflections at the tapers lead to resonant behaviour of the cavity (Kartikeyan et al 2004; Flyagin et al ...

  6. Active mode control of solid state laser using an intra-cavity beam shaper

    Science.gov (United States)

    Liu, Wenguang; Zhou, Qiong; Yan, Baozhu; Jiang, Zongfu

    2015-05-01

    In high power solid state lasers, thermal lens effect always give rise to the multi-modes oscillation in the resonator. The beam quality will deteriorate with the increase of output power. In this paper, an intra-cavity beam shaper is introduced to actively compensate the thermal lens in the laser resonator. One round trip ABCD matrix of the resonator with an intra-cavity beam shaper and thermal lens is calculated. The design parameters with wide stable zone are concluded through the ABCD matrix. The mode size and stability diagram of the resonator are calculated under different focal length of the thermal lens. The relationship between the adjustment of the intra-cavity beam shaper and the mode size under different thermal lenses are concluded, and general method to actively control the modes contents by adjusting the intra-cavity beam shaper is introduced. The effectiveness and performance of active mode control with the intra-cavity beam shaper are verified by simulations of the output modes of resonators. It shows that the M2 factor is well maintained below 1.6 even the focal length of the thermal lens changes from 5m to 0.5m.

  7. Lasing by driven atoms-cavity system in collective strong coupling regime.

    Science.gov (United States)

    Sawant, Rahul; Rangwala, S A

    2017-09-12

    The interaction of laser cooled atoms with resonant light is determined by the natural linewidth of the excited state. An optical cavity is another optically resonant system where the loss from the cavity determines the resonant optical response of the system. The near resonant combination of an optical Fabry-Pérot cavity with laser cooled and trapped atoms couples two distinct optical resonators via light and has great potential for precision measurements and the creation of versatile quantum optics systems. Here we show how driven magneto-optically trapped atoms in collective strong coupling regime with the cavity leads to lasing at a frequency red detuned from the atomic transition. Lasing is demonstrated experimentally by the observation of a lasing threshold accompanied by polarization and spatial mode purity, and line-narrowing in the outcoupled light. Spontaneous emission into the cavity mode by the driven atoms stimulates lasing action, which is capable of operating as a continuous wave laser in steady state, without a seed laser. The system is modeled theoretically, and qualitative agreement with experimentally observed lasing is seen. Our result opens up a range of new measurement possibilities with this system.

  8. High-power Microwave Pulse Compression of Klystrons by Phase-Modulation of High-Q Storage Cavities

    CERN Document Server

    Bossart, Rudolf; Mourier, J; Syratchev, I V; Tanner, L

    2004-01-01

    At the CERN linear electron accelerators LIL and CTF, the peak RF power from the 3GHz-klystrons was doubled by means of LIPS microwave pulse compressors. To produce constant RF power from the cavity-based pulse compressors, the klystrons were driven by a fast RF-phase modulation program. For the CLIC Test Facility CTF3, a new type of a Barrel Open Cavity (BOC) with a high quality factor Q0 has been developed. Contrary to LIPS with two resonant cavities, BOC operates with a single cavity supporting two orthogonal resonant modes TM 10,1,1 in the same cavity. For both LIPS and BOC storage cavities, it is important that the RF power reflected back to the klystron is minimal. This implies that the resonant frequencies, Q-factors and coupling factors of the two resonant modes of a pulse compressor are closely matched, and that the resonant frequencies are accurate to within a few KHz. The effects of small differences between the two orthogonal modes of the BOC cavity have been investigated. The dynamic pulse respon...

  9. Cavity-type hypersonic phononic crystals

    International Nuclear Information System (INIS)

    Sato, A; Fytas, G; Pennec, Y; Djafari-Rouhani, B; Yanagishita, T; Masuda, H; Knoll, W

    2012-01-01

    We report on the engineering of the phonon dispersion diagram in monodomain anodic porous alumina (APA) films through the porosity and physical state of the material residing in the nanopores. Lattice symmetry and inclusion materials are theoretically identified to be the main factors which control the hypersonic acoustic wave propagation. This involves the interaction between the longitudinal and the transverse modes in the effective medium and a flat band characteristic of the material residing in the cavities. Air and filled nanopores, therefore, display markedly different dispersion relations and the inclusion materials lead to a locally resonant structural behavior uniquely determining their properties under confinement. APA films emerge as a new platform to investigate the rich acoustic phenomena of structured composite matter. (paper)

  10. Cavity Microwave Searches for Cosmological Axions

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    The lecture will cover the searches for dark matter axions based on the microwave cavity experiment of Sikivie. The topics will begin with a brief overview of halo dark matter, and the axion as a candidate. The principle of resonant conversion of axions in an external magnetic field will be described, and practical considerations in optimizing the experiment as a signal-to-noise problem. A major focus of the lecture will be the two complementary strategies for ultra-low noise detection of the microwave photons - the "photon-as-wave" approach (i.e. conventional heterojunction amplifiers and soon quantum-limited SQUID devices), and "photon-as-particle" (i.e. Rydberg-atom single-quantum detection). Experimental results will be presented; these experiments have already reached well into the range of sensitivity to exclude plausible axion models, for limited ranges of mass. The lecture will conclude with a discussion of future plans and challenges for the microwave ca...

  11. Cavity optomechanics in gallium phosphide microdisks

    International Nuclear Information System (INIS)

    Mitchell, Matthew; Barclay, Paul E.; Hryciw, Aaron C.

    2014-01-01

    We demonstrate gallium phosphide (GaP) microdisk optical cavities with intrinsic quality factors >2.8 × 10 5 and mode volumes 3 , and study their nonlinear and optomechanical properties. For optical intensities up to 8.0 × 10 4 intracavity photons, we observe optical loss in the microcavity to decrease with increasing intensity, indicating that saturable absorption sites are present in the GaP material, and that two-photon absorption is not significant. We observe optomechanical coupling between optical modes of the microdisk around 1.5 μm and several mechanical resonances, and measure an optical spring effect consistent with a theoretically predicted optomechanical coupling rate g 0 /2π∼30 kHz for the fundamental mechanical radial breathing mode at 488 MHz

  12. Cavity Microwave Searches for Cosmological Axions

    Energy Technology Data Exchange (ETDEWEB)

    Carosi, G; van Bibber, K

    2007-01-22

    This chapter will cover the search for dark matter axions based on microwave cavity experiments proposed by Pierre Sikivie. We will start with a brief overview of halo dark matter and the axion as a candidate. The principle of resonant conversion of axions in an external magnetic field will be described as well as practical considerations in optimizing the experiment as a signal-to-noise problem. A major focus of this chapter will be the two complementary strategies for ultra-low noise detection of the microwave photons--the 'photon-as-wave' approach (i.e. conventional heterojunction amplifiers and soon to be quantum-limited SQUID devices), and 'photon-as-particle' (i.e. Rydberg-atom single-quantum detection). Experimental results will be presented; these experiments have already reached well into the range of sensitivity to exclude plausible axion models, for limited ranges of mass. The section will conclude with a discussion of future plans and challenges for the microwave cavity experiment.

  13. Simulation of Multipacting in SC Low Beta Cavities at FNAL

    Energy Technology Data Exchange (ETDEWEB)

    Romanov, Gennady [Fermilab; Berrutti, Paolo [Fermilab; Khabiboulline, Timergali [Fermilab

    2015-06-01

    Proton Improvement Plan-II at Fermilab is a plan for improvements to the accelerator complex aimed at providing a beam power capability of at least 1 MW on target at the initiation of LBNE (Long Base Neutrino Experiment) operations. The central element of the PIP-II is a new 800 MeV superconducting linac, injecting into the existing Booster. Multipacting affects superconducting RF cavities in the entire range from high energy elliptical cavities to coaxial resonators for low-beta applications. This work is focused on multipacting study in the low-beta 325 MHz spoke cavities; namely SSR1 and SSR2, which are especially susceptible to the phenomena. The extensive simulations of multipacting in the cavities with updated material properties and comparison of the results with experimental data helped us to improve overall reliability and accuracy of these simulations. Our practical approach to the simulations is described in details. For SSR2, which has a high multipacting barrier right at the operating power level, some changes of the cavity shape to mitigate this harmful phenomenon are proposed.

  14. Effect of low temperature baking on niobium cavities

    Energy Technology Data Exchange (ETDEWEB)

    Peter Kneisel; Ganapati Myneni; William Lanford; Gianluigi Ciovati

    2003-09-01

    A low temperature (100 C-150 C) ''in situ'' baking under ultra-high vacuum has been successfully applied as final preparation of niobium RF cavities by several laboratories over the last few years. The benefits reported consist mainly of an improvement of the cavity quality factor and a recovery from the so-called ''Q-drop'' without field emission at high field. A series of experiments with a CEBAF single cell cavity have been carried out at Jefferson Lab to carefully investigate the effect of baking at progressively higher temperatures for a fixed time on all the relevant material parameters. Measurements of the cavity quality factor in the temperature range 1.37K-280K and resonant frequency shift between 6K-9.3K provide information about the surface resistance, energy gap, penetration depth and mean free path. The experimental data have been analyzed with the complete BCS theory of superconductivity using a modified version of the computer code originally written by J. Halbritter [1] . Small niobium samples inserted in the cavity during its surface preparation were analyzed with respect to their hydrogen content with a Nuclear Reaction Analysis (NRA). The single cell cavity has been tested at three different temperatures before and after baking to gain some insight on thermal conductivity and Kapitza resistance and the data are compared with different models. This paper describes the results from these experiments and comments on the existing models to explain the effect of baking on the performance of niobium RF cavities.

  15. Gain-assisted broadband ring cavity enhanced spectroscopy

    Science.gov (United States)

    Selim, Mahmoud A.; Adib, George A.; Sabry, Yasser M.; Khalil, Diaa

    2017-02-01

    Incoherent broadband cavity enhanced spectroscopy can significantly increase the effective path length of light-matter interaction to detect weak absorption lines over broad spectral range, for instance to detect gases in confined environments. Broadband cavity enhancement can be based on the decay time or the intensity drop technique. Decay time measurement is based on using tunable laser source that is expensive and suffers from long scan time. Intensity dependent measurement is usually reported based on broadband source using Fabry-Perot cavity, enabling short measurement time but suffers from the alignment tolerance of the cavity and the cavity insertion loss. In this work we overcome these challenges by using an alignment-free ring cavity made of an optical fiber loop and a directional coupler, while having a gain medium pumped below the lasing threshold to improve the finesse and reduce the insertion loss. Acetylene (C2H2) gas absorption is measured around 1535 nm wavelength using a semiconductor optical amplifier (SOA) gain medium. The system is analyzed for different ring resonator forward coupling coefficient and loses, including the 3-cm long gas cell insertion loss and fiber connector losses used in the experimental verification. The experimental results are obtained for a coupler ratio of 90/10 and a fiber length of 4 m. The broadband source is the amplified spontaneous emission of another SOA and the output is measured using a 70pm-resolution optical spectrum analyzer. The absorption depth and the effective interaction length are improved about an order of magnitude compared to the direct absorption of the gas cell. The presented technique provides an engineering method to improve the finesse and, consequently the effective length, while relaxing the technological constraints on the high reflectivity mirrors and free-space cavity alignment.

  16. Graphene photonics for resonator-enhanced electro-optic devices and all-optical interactions

    Science.gov (United States)

    Englund, Dirk R.; Gan, Xuetao

    2017-03-21

    Techniques for coupling light into graphene using a planar photonic crystal having a resonant cavity characterized by a mode volume and a quality factor and at least one graphene layer positioned in proximity to the planar photonic crystal to at least partially overlap with an evanescent field of the resonant cavity. At least one mode of the resonant cavity can couple into the graphene layer via evanescent coupling. The optical properties of the graphene layer can be controlled, and characteristics of the graphene-cavity system can be detected. Coupling light into graphene can include electro-optic modulation of light, photodetection, saturable absorption, bistability, and autocorrelation.

  17. Bistability of Cavity Magnon Polaritons

    Science.gov (United States)

    Wang, Yi-Pu; Zhang, Guo-Qiang; Zhang, Dengke; Li, Tie-Fu; Hu, C.-M.; You, J. Q.

    2018-01-01

    We report the first observation of the magnon-polariton bistability in a cavity magnonics system consisting of cavity photons strongly interacting with the magnons in a small yttrium iron garnet (YIG) sphere. The bistable behaviors emerged as sharp frequency switchings of the cavity magnon polaritons (CMPs) and related to the transition between states with large and small numbers of polaritons. In our experiment, we align, respectively, the [100] and [110] crystallographic axes of the YIG sphere parallel to the static magnetic field and find very different bistable behaviors (e.g., clockwise and counter-clockwise hysteresis loops) in these two cases. The experimental results are well fitted and explained as being due to the Kerr nonlinearity with either a positive or negative coefficient. Moreover, when the magnetic field is tuned away from the anticrossing point of CMPs, we observe simultaneous bistability of both magnons and cavity photons by applying a drive field on the lower branch.

  18. Niobium LEP 2 accelerating cavities

    CERN Multimedia

    An accelerating cavity from LEP. This could be cut open to show the layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities were used in an upgrade of the LEP accelerator to double the energy of the particle beams.

  19. Loggerhead oral cavity morphometry study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Standard external morphometrics and internal oral cavity morphometrics data were collected on wild and captive reared loggerhead sea turtles in size classes ranging...

  20. SRF Cavity Fabrication and Materials

    CERN Document Server

    Singer, W

    2014-07-17

    The technological and metallurgical requirements of material for highgradient superconducting cavities are described. High-purity niobium, as the preferred metal for the fabrication of superconducting accelerating cavities, should meet exact specifications. The content of interstitial impurities such as oxygen, nitrogen, and carbon must be below 10μg/g. The hydrogen content should be kept below 2μg/g to prevent degradation of the Q-value under certain cool-down conditions. The material should be free of flaws (foreign material inclusions or cracks and laminations) that can initiate a thermal breakdown. Defects may be detected by quality control methods such as eddy current scanning and identified by a number of special methods. Conventional and alternative cavity fabrication methods are reviewed. Conventionally, niobium cavities are fabricated from sheet niobium by the formation of half-cells by deep drawing, followed by trim machining and Electron-Beam Welding (EBW). The welding of half-cells is a delicate...

  1. Bistability of Cavity Magnon Polaritons.

    Science.gov (United States)

    Wang, Yi-Pu; Zhang, Guo-Qiang; Zhang, Dengke; Li, Tie-Fu; Hu, C-M; You, J Q

    2018-02-02

    We report the first observation of the magnon-polariton bistability in a cavity magnonics system consisting of cavity photons strongly interacting with the magnons in a small yttrium iron garnet (YIG) sphere. The bistable behaviors emerged as sharp frequency switchings of the cavity magnon polaritons (CMPs) and related to the transition between states with large and small numbers of polaritons. In our experiment, we align, respectively, the [100] and [110] crystallographic axes of the YIG sphere parallel to the static magnetic field and find very different bistable behaviors (e.g., clockwise and counter-clockwise hysteresis loops) in these two cases. The experimental results are well fitted and explained as being due to the Kerr nonlinearity with either a positive or negative coefficient. Moreover, when the magnetic field is tuned away from the anticrossing point of CMPs, we observe simultaneous bistability of both magnons and cavity photons by applying a drive field on the lower branch.

  2. Magnetic resonance spectroscopy of single centers in silicon quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Bagraev, Nikolay T., E-mail: impurity.dipole@mail.ioffe.r [Ioffe Physical-Technical Institute, 194021 St. Petersburg (Russian Federation); Klyachkin, Leonid E.; Kudryavtsev, Andrey A.; Malyarenko, Anna M. [Ioffe Physical-Technical Institute, 194021 St. Petersburg (Russian Federation)

    2009-12-15

    We present the new optically detected magnetic resonance (ODMR) technique which reveals single point defects in silicon quantum wells embedded in microcavities within frameworks of the excitonic normal-mode coupling (NMC) without the external cavity and the hf source.

  3. Molecular-Resonance Fiber Optic Gas Sensors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Aspen systems proposes to develop an innovative and smart sensors to continuously monitor ambient air compositions by utilizing a resonating tunable micro-cavity...

  4. Sterility of the uterine cavity

    DEFF Research Database (Denmark)

    Møller, Birger R.; Kristiansen, Frank V.; Thorsen, Poul

    1995-01-01

    In a prospective open study the sterility of the uterine cavity was evaluated in 99 women admitted for hysterectomy. The indications for hysterectomy were in most cases persistent irregular vaginal bleeding and fibromyomas of the uterus. Samples for both aerobic and anaerobic bacteria, Chlamydia ...... which may play a causative role in endometritis. The results indicate that inflammation of the uterine cavity should be evaluated by hysteroscopic examination before hysterectomy is undertaken in patients with persistent irregular vaginal bleeding. Udgivelsesdato: 1995-Mar...

  5. LEP Radio Frequency Copper Cavity

    CERN Multimedia

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  6. Mechanical optimization of superconducting cavities in continuous wave operation

    Directory of Open Access Journals (Sweden)

    Sam Posen

    2012-02-01

    Full Text Available Several planned accelerator facilities call for hundreds of elliptical cavities operating cw with low effective beam loading, and therefore require cavities that have been mechanically optimized to operate at high Q_{L} by minimizing df/dp, the sensitivity to microphonics detuning from fluctuations in helium pressure. Without such an optimization, the facilities would suffer either power costs driven up by millions of dollars or an extremely high per-cavity trip rate. ANSYS simulations used to predict df/dp are presented as well as a model that illustrates factors that contribute to this parameter in elliptical cavities. For the Cornell Energy Recovery Linac (ERL main linac cavity, df/dp is found to range from 2.5 to 17.4  Hz/mbar, depending on the radius of the stiffening rings, with minimal df/dp for very small or very large radii. For the Cornell ERL injector cavity, simulations predict a df/dp of 124  Hz/mbar, which fits well within the range of measurements performed with the injector cryomodule. Several methods for reducing df/dp are proposed, including decreasing the diameter of the tuner bellows and increasing the stiffness of the enddishes and the tuner. Using measurements from a Tesla Test Facility cavity as the baseline, if both of these measures were implemented and the stiffening rings were optimized, simulations indicate that df/dp would be reduced from ∼30  Hz/mbar to just 2.9  Hz/mbar, and the power required to maintain the accelerating field would be reduced by an order of magnitude. Finally, other consequences of optimizing the stiffening ring radius are investigated. It is found that stiffening rings larger than 70% of the iris-equator distance make the cavity impossible to tune. Small rings, on the other hand, leave the cavity susceptible to plastic deformation during handling and have lower frequency mechanical resonances, which is undesirable for active compensation of microphonics. Additional simulations

  7. Quantum dynamics of crystals of molecular magnets inside microwave resonators

    Energy Technology Data Exchange (ETDEWEB)

    Amigo, R.; Tejada, J.; Chudnovsky, E.M.; Hernandez, J.M.; Garcia-Santiago, A. E-mail: antonio@ubxlab.comtoni@ubxlab.com

    2004-05-01

    It is shown that crystals of molecular nanomagnets exhibit enhanced magnetic relaxation when placed inside a resonant cavity. Strong dependence of the magnetization curve on the geometry of the cavity has been observed, providing evidence of the coherent microwave radiation by the crystals. These observations open the possibility of building a nanomagnetic microwave laser pumped by the magnetic field.

  8. Quantum dynamics of crystals of molecular magnets inside microwave resonators

    International Nuclear Information System (INIS)

    Amigo, R.; Tejada, J.; Chudnovsky, E.M.; Hernandez, J.M.; Garcia-Santiago, A.

    2004-01-01

    It is shown that crystals of molecular nanomagnets exhibit enhanced magnetic relaxation when placed inside a resonant cavity. Strong dependence of the magnetization curve on the geometry of the cavity has been observed, providing evidence of the coherent microwave radiation by the crystals. These observations open the possibility of building a nanomagnetic microwave laser pumped by the magnetic field

  9. An Experiment and Detection Scheme for Cavity-Based Light Cold Dark Matter Particle Searches

    Directory of Open Access Journals (Sweden)

    Masroor H. S. Bukhari

    2017-01-01

    Full Text Available A resonance detection scheme and some useful ideas for cavity-based searches of light cold dark matter particles (such as axions are presented, as an effort to aid in the on-going endeavors in this direction as well as for future experiments, especially in possibly developing a table-top experiment. The scheme is based on our idea of a resonant detector, incorporating an integrated tunnel diode (TD and GaAs HEMT/HFET (High-Electron Mobility Transistor/Heterogeneous FET transistor amplifier, weakly coupled to a cavity in a strong transverse magnetic field. The TD-amplifier combination is suggested as a sensitive and simple technique to facilitate resonance detection within the cavity while maintaining excellent noise performance, whereas our proposed Halbach magnet array could serve as a low-noise and permanent solution replacing the conventional electromagnets scheme. We present some preliminary test results which demonstrate resonance detection from simulated test signals in a small optimal axion mass range with superior signal-to-noise ratios (SNR. Our suggested design also contains an overview of a simpler on-resonance dc signal read-out scheme replacing the complicated heterodyne read-out. We believe that all these factors and our propositions could possibly improve or at least simplify the resonance detection and read-out in cavity-based DM particle detection searches (and other spectroscopy applications and reduce the complications (and associated costs, in addition to reducing the electromagnetic interference and background.

  10. Optofluidic ring resonator dye lasers

    Science.gov (United States)

    Sun, Yuze; Suter, Jonathan D.; Fan, Xudong

    2010-02-01

    We overview the recent progress on optofluidic ring resonator (OFRR) dye lasers developed in our research group. The fluidics and laser cavity design can be divided into three categories: capillary optofluidic ring resonator (COFRR), integrated cylindrical optofluidic ring resonator (ICOFRR), and coupled optofluidic ring resonator (CpOFRR). The COFRR dye laser is based on a micro-sized glass capillary with a wall thickness of a few micrometers. The capillary circular cross-section forms the ring resonator and supports the whispering gallery modes (WGMs) that interact evanescently with the gain medium in the core. The laser cavity structure is versatile to adapt to the gain medium of any refractive index. Owing to the high Q-factor (>109), the lasing threshold of 25 nJ/mm2 is achieved. Besides directly pump the dye molecules, lasing through fluorescence resonance energy transfer (FRET) between the donor and acceptor dye molecules is also studied in COFRR laser. The energy transfer process can be further controlled by designed DNA scaffold labeled with donor/acceptor molecules. The ICOFRR dye laser is based on a cylindrical ring resonator fused onto the inner surface of a thick walled glass capillary. The structure has robust mechanical strength to sustain rapid gain medium circulation. The CpOFRR utilizes a cylindrical ring resonator fused on the inner surface of the COFRR capillary. Since the capillary wall is thin, the individual WGMs of the cylindrical ring resonator and the COFRR couples strongly and forms Vernier effect, which provides a way to generate a single mode dye laser.

  11. Mechanical resonator

    OpenAIRE

    Padowitz, David; Matsiev, L; Kolosov, Oleg

    2004-01-01

    A sensor and methods for making and using the same in which a mechanical resonator is employed, comprising a resonator portion for resonating in a fluid without the substantial generation of acoustic waves; and an electrical connection between the resonator portion for oscillating and a source of an input signal; wherein the portion for resonating, the electrical connection or both includes a base material and a performance-tuning material that is different from the base material.

  12. A highly directive graphene antenna embedded inside a Fabry-Perot cavity in terahertz regime

    Science.gov (United States)

    Roshanaei, Majid; Karami, Hamidreza; Dehkhoda, Parisa; Esfahani, Hamid; Dabir, Fatemeh

    2018-05-01

    In this paper, a highly directive nano-thickness graphene-based antenna is introduced in the terahertz frequency band. The antenna is a graphene patch dipole which is placed between two Bragg mirrors called Fabry-Perot cavity. Tunability of the graphene's conductivity makes it possible to excite the desired resonances of the cavity. Here, first, a single resonant antenna is introduced at 5 THz with an enhanced gain from 2.11 dBi to 12.8 dBi with a beamwidth of 22.7°. Then, a triple resonant antenna at 4.7, 5 and 5.3 THz is presented with respective gains of 7.97, 11.9 and 8.52 dBi. Finally, the effect of dimensions and number of the dielectric layers of the cavity are studied in order to further increase in directivity.

  13. Mechanical design upgrade of the APS storage ring rf cavity tuner

    International Nuclear Information System (INIS)

    Jones, J.; Bromberek, D.; Kang, Y.

    1997-01-01

    The Advanced Photon Source (APS) storage ring (SR) rf system employs four banks of four spherical, single-cell resonant cavities. Each cavity is tuned by varying the cavity volume through insertion/retraction of a copper piston located at the circumference of the cavity and oriented perpendicular to the accelerator beam. During the commissioning of the APS SR, the tuners and cavity tuner ports were prone to extensive arcing and overheating. The existing tuners were modified to eliminate the problems, and two new, redesigned tuners were installed. In both cases marked improvements were obtained in the tuner mechanical performance. As measured by tuner piston and flange surface temperatures, tuner heating has been reduced by a factor of five in the new version. Redesign considerations discussed include tuner piston-to-housing alignment, tuner piston and housing materials and cooling configurations, and tuner piston sliding electrical contacts. The tuner redesign is also distinguished by a modular, more maintainable assembly

  14. Deterministic creation of Schrodinger cat states in a superconducting waveguide cavity

    Science.gov (United States)

    Vlastakis, Brian; Kirchmair, Gerhard; Leghtas, Zaki; Nigg, Simon; Frunzio, Luigi; Girvin, Steven; Mirrahimi, Mazyar; Schoelkopf, Robert

    2013-03-01

    Off-resonant coupling of a superconducting transmon qubit to a three-dimensional waveguide cavity provides a dispersive qubit/cavity interaction much stronger than any decay rates in the system. Using a two-cavity/single-qubit architecture, we utilize this interaction to deterministically map a qubit state to a superposition of coherent states in a cavity (up to a 40 photon separation). By measuring photon-number parity, we perform Wigner tomography that shows the characteristic interference inherent in quantum superpositions, thus confirming the non-classical properties of the cavity state. Furthermore, we extend this method to create multi-component Schrodinger cat states including the four-component compass state.

  15. Controllable optical bistability in a three-mode optomechanical system with atom-cavity-mirror couplings

    Science.gov (United States)

    Chen, Bin; Wang, Xiao-Fang; Yan, Jia-Kai; Zhu, Xiao-Fei; Jiang, Cheng

    2018-01-01

    We theoretically investigate the optical bistable behavior in a three-mode optomechanical system with atom-cavity-mirror couplings. The effects of the cavity-pump detuning and the pump power on the bistable behavior are discussed detailedly, the impacts of the atom-pump detuning and the atom-cavity coupling strength on the bistability of the system are also explored, and the influences of the cavity-resonator coupling strength and the cavity decay rate are also taken into consideration. The numerical results demonstrate that by tuning these parameters the bistable behavior of the system can be freely switched on or off, and the threshold of the pump power for the bistability as well as the bistable region width can also be effectively controlled. These results can find potential applications in optical bistable switch in the quantum information processing.

  16. High performance graphene oxide-based humidity sensor integrated on a photonic crystal cavity

    Science.gov (United States)

    Gan, Xuetao; Zhao, Chenyang; Yuan, Qingchen; Fang, Liang; Li, Yongjiang; Yin, Jianbo; Ma, Xiaoyan; Zhao, Jianlin

    2017-04-01

    We report a high performance relative humidity (RH) microsensor based on a few-layer graphene oxide (GO) flake coated photonic crystal (PC) cavity. Since the GO layer is highly water-reactive and interacts with the evanescent cavity mode strongly, the exposure of the GO-PC cavity in varied humidity levels results in significant resonant wavelength shifts, showing a slope of 0.68 nm/%RH in the range of 60%-85%RH. By monitoring the power variation of the cavity reflection, the microsensor presents an ultrahigh sensitivity exceeding 3.9 dB/%RH. Relying on the unimpeded permeation of water molecules through the GO interlayers and microscale distribution of the cavity mode, the integrated sensor has a response time less than 100 ms, which promises successful measurements of human breathing. Combining with the ease of fabrication, this high performance RH sensor provides great potentials in applications requiring optical access, device compactness, and fast dynamic response.

  17. Polarization-selectable cavity locking method for generation of laser Compton scattered γ-rays.

    Science.gov (United States)

    Kosuge, Atsushi; Mori, Michiaki; Okada, Hajime; Hajima, Ryoichi; Nagashima, Keisuke

    2014-03-24

    Nowadays, generation of energy-tunable, monochromatic γ-rays is needed to establish a nondestructive assay method of nuclear fuel materials. The γ-rays are generated by collision of laser photons stored in a cavity and relativistic electrons. We propose a configuration of an enhancement cavity capable of performing polarization control fabricated by a combination of a four-mirror ring cavity with a small spot inside a cavity and a three-mirror of reflective optics as an image inverter for polarization-selectable γ-rays. The image inverter introduces a phase shift of specific polarization which can be used to generate an error signal to lock an optical cavity at a resonance condition.

  18. 21 CFR 872.3260 - Cavity varnish.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cavity varnish. 872.3260 Section 872.3260 Food and... DENTAL DEVICES Prosthetic Devices § 872.3260 Cavity varnish. (a) Identification. Cavity varnish is a device that consists of a compound intended to coat a prepared cavity of a tooth before insertion of...

  19. Resonance-shifting luminescent solar concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Giebink, Noel Christopher; Wiederrecht, Gary P; Wasielewski, Michael R

    2014-09-23

    An optical system and method to overcome luminescent solar concentrator inefficiencies by resonance-shifting, in which sharply directed emission from a bi-layer cavity into a glass substrate returns to interact with the cavity off-resonance at each subsequent reflection, significantly reducing reabsorption loss en route to the edges. In one embodiment, the system comprises a luminescent solar concentrator comprising a transparent substrate, a luminescent film having a variable thickness; and a low refractive index layer disposed between the transparent substrate and the luminescent film.

  20. Resonance-shifting luminescent solar concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Giebink, Noel Christopher; Wiederrecht, Gary P.; Wasielewski, Michael R.

    2018-01-23

    An optical system and method to overcome luminescent solar concentrator inefficiencies by resonance-shifting, in which sharply directed emission from a bi-layer cavity into a glass substrate returns to interact with the cavity off-resonance at each subsequent reflection, significantly reducing reabsorption loss en route to the edges. In one embodiment, the system comprises a luminescent solar concentrator comprising a transparent substrate, a luminescent film having a variable thickness; and a low refractive index layer disposed between the transparent substrate and the luminescent film.

  1. Terahertz gas sensing based on a simple one-dimensional photonic crystal cavity with high-quality factors

    DEFF Research Database (Denmark)

    Chen, T.; Han, Z. H.; Liu, J. J.

    2014-01-01

    We report in this paper terahertz gas sensing using a simple 1D photonic crystal cavity. The resonant frequencies of the cavity depend linearly on the refractive index of the ambient gas, which can then be measured by monitoring the resonance shift. Although quite easy to manufacture, this cavity...... exhibits high-quality factors, facilitating the realization of high sensitivity in the gas refractive index sensing. In our experiment, 6% of the change of hydrogen concentration in air, which corresponds to a refractive index change of 1.4 x 10(-5), can be steadily detected, and different gas samples can...

  2. Simultaneous cooling and entanglement of mechanical modes of a micromirror in an optical cavity

    International Nuclear Information System (INIS)

    Genes, Claudiu; Vitali, David; Tombesi, Paolo

    2008-01-01

    Laser cooling of a mechanical mode of a resonator by the radiation pressure of a detuned optical cavity mode has been recently demonstrated by various groups in different experimental configurations. Here, we consider the effect of a second mechanical mode with a close but different resonance frequency. We show that the nearby mechanical resonance is simultaneously cooled by the cavity field, provided that the difference between the two mechanical frequencies is not too small. When this frequency difference becomes smaller than the effective mechanical damping of the secondary mode, the two cooling processes interfere destructively similarly to what happens in electromagnetically induced transparency, and cavity cooling is suppressed in the limit of identical mechanical frequencies. We show that also the entanglement properties of the steady state of the tripartite system crucially depend upon the difference between the two mechanical frequencies. If the latter is larger than the effective damping of the second mechanical mode, the state shows fully tripartite entanglement and each mechanical mode is entangled with the cavity mode. If instead, the frequency difference is smaller, the steady state is a two-mode biseparable state, inseparable only when one splits the cavity mode from the two mechanical modes. In this latter case, the entanglement of each mechanical mode with the cavity mode is extremely fragile with respect to temperature.

  3. Development of niobium spoke cavities for a superconducting light-ion linac

    International Nuclear Information System (INIS)

    Shepard, K.W.; Kedzie, M.; Delayen, J.R.; Piller, C.

    1998-01-01

    This paper reports the development of 350 MHz niobium superconducting cavities for the velocity range 0.2 < v/c < 0.6. Such cavities could be used to form a linac of exceptional flexibility, capable of efficiently accelerating beams of either protons, deuterons, or any of a wide range of ions, at intensities sufficient for a production beam for a radioactive facility. Results of numerical modeling for several resonator geometries are presented. The design and construction status of prototype niobium cavities is discussed

  4. Analysis of the impacts of mechanical errors on the RF performance of a single spoke cavity

    International Nuclear Information System (INIS)

    Yao Zhongyuan; Lu Xiangyang; Zhang Baocheng; Quan Shengwen; He Feisi; Zhao Kui

    2010-01-01

    Mechanical errors can not be avoided in fabrication. They will cause geometry errors and have impacts on the cavity performance. This paper systematically analyzes the impacts of mechanical errors on the RF performance of Peking University single spoke cavity. The various kinds of shape and size errors are considered, the influences on the resonation frequency and field flatness are studied by numerical simulation and the theoretical models are analyzed. The results show that the single spoke cavity is robust with respect to the mechanical tolerance. It also indicates the most essential factors for fabrication. (authors)

  5. Effective length of short Fabry-Perot cavity formed by uniform fiber Bragg gratings.

    Science.gov (United States)

    Barmenkov, Yuri O; Zalvidea, Dobryna; Torres-Peiró, Salvador; Cruz, Jose L; Andrés, Miguel V

    2006-07-10

    In this paper, we describe the properties of Fabry-Perot fiber cavity formed by two fiber Bragg gratings in terms of the grating effective length. We show that the grating effective length is determined by the group delay of the grating, which depends on its diffraction efficiency and physical length. We present a simple analytical formula for calculation of the effective length of the uniform fiber Bragg grating and the frequency separation between consecutive resonances of a Fabry-Perot cavity. Experimental results on the cavity transmission spectra for different values of the gratings' reflectivity support the presented theory.

  6. Development of niobium spoke cavities for a superconducting light-ion Linac.

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K. W.

    1998-11-18

    This paper reports the development of 350 MHz niobium superconducting cavities for the velocity range 0.2< v/c <0.6. Such cavities could be used to form a linac of exceptional flexibility, capable of efficiently accelerating beams of either protons, deuterons, or any of a wide range of light ions, at intensities sufficient for a production beam for a radioactive beam facility. Results of numerical modeling for several resonator geometries are presented. The design and construction status of prototype niobium cavities is discussed.

  7. Development of niobium spoke cavities for a superconducting light-ion linac

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K W; Kedzie, M; Delayen, J R; Piller, C

    1998-08-01

    This paper reports the development of 350 MHz niobium superconducting cavities for the velocity range 0.2 < v/c < 0.6. Such cavities could be used to form a linac of exceptional flexibility, capable of efficiently accelerating beams of either protons, deuterons, or any of a wide range of ions, at intensities sufficient for a production beam for a radioactive facility. Results of numerical modeling for several resonator geometries are presented. The design and construction status of prototype niobium cavities is discussed.

  8. Development of niobium spoke cavities for a superconducting light-ion Linac

    International Nuclear Information System (INIS)

    Shepard, K. W.

    1998-01-01

    This paper reports the development of 350 MHz niobium superconducting cavities for the velocity range 0.2< v/c <0.6. Such cavities could be used to form a linac of exceptional flexibility, capable of efficiently accelerating beams of either protons, deuterons, or any of a wide range of light ions, at intensities sufficient for a production beam for a radioactive beam facility. Results of numerical modeling for several resonator geometries are presented. The design and construction status of prototype niobium cavities is discussed

  9. Contribution of thermal noise to frequency stability of rigid optical cavity via Hertz-linewidth lasers

    International Nuclear Information System (INIS)

    Notcutt, Mark; Ma, L.-S.; Ludlow, Andrew D.; Foreman, Seth M.; Ye Jun; Hall, John L.

    2006-01-01

    We perform detailed studies of state-of-the-art laser stabilization to high finesse optical cavities, revealing fundamental mechanical thermal noise-related length fluctuations. We compare the frequency noise of lasers tightly locked to the resonances of a variety of rigid Fabry-Perot cavities of differing lengths and mirror substrate materials. The results are in agreement with the theoretical model proposed in K. Numata, A. Kemery, and J. Camp [Phys. Rev. Lett. 93, 250602 (2004)]. The results presented here on the fundamental limits of FP references will impact planning and construction of next generation ultrastable optical cavities

  10. Mode conversion in metal–insulator–metal waveguide with a shifted cavity

    Science.gov (United States)

    Wang, Yueke; Yan, Xin

    2018-01-01

    We propose a method, which is utilized to achieve the plasmonic mode conversion in metal–insulator–metal (MIM) waveguide, theoretically. Our proposed structure is composed of bus waveguides and a shifted cavity. The shifted cavity can choose out a plasmonic mode (a- or s-mode) when it is in Fabry–Perot (FP) resonance. The length of the shifted cavity L is carefully chosen, and our structure can achieve the mode conversion between a- and s-mode in the communication region. Besides, our proposed structure can also achieve plasmonic mode-division multiplexing. All the numerical simulations are carried on by the finite element method to verify our design.

  11. Combined endovascular and surgical treatment of melanoma of the nasal cavity: a case report

    International Nuclear Information System (INIS)

    Romero, A.; Delgado, F.; Ramos, M.; Bravo, F.

    2000-01-01

    Melanoma of the nasal cavity is a rare tumor with a worse prognosis than cutaneous melanoma. It usually presents as nasal obstruction and/or epistaxis. The observation of a pigmented mass in the nasal cavity is highly suggestive of this lesion. Computed tomography shows a mass with nonspecific features. In magnetic resonance studies, it has a characteristics signal consisting of hyperintensity of T1-weighted images and hypointensity on T2-weighted images, depending on the amount of melanin. The treatment of choice is surgical resection. We present a case of melanoma of the nasal cavity in which endovascular embolization of the tumor was performed prior to surgical treatment. (Author) 11 refs

  12. Engineering interactions between long-lived cavities

    Science.gov (United States)

    Gao, Yvonne; Rosenblum, Serge; Reinhold, Philip; Wang, Chen; Axline, Christopher; Frunzio, Luigi; Girvin, Steven M.; Jiang, Liang; Mirrahimi, Mazyar; Devoret, Michel H.; Schoelkopf, Robert J.

    The availability of large Hilbert dimensions and outstanding coherence properties make superconducting cavities promising systems for storing quantum information. Recent experiments in cQED has demonstrated that redundantly encoding logical qubits in such cavities is a hardware-efficient approach toward error-correctable quantum memories. In order to tap into the power of these protected memories for quantum information processing, robust inter-cavity operations are required. A simple way to realise such operations between two cavities is using the non-linearity of the Josephson junction. To do so, we adopt a multi-cavity architecture where a fixed-frequency, single junction transmon simultaneously couples to two highly coherent 3D cavities. Using only external RF drives, we demonstrate transmon-cavity as well as cavity-cavity SWAP operations and show that such interactions are essential building blocks for implementing multi-cavity conditional logics.

  13. Investigation on the fabrication of the 3rd harmonic superconducting cavity for the SSRF storage ring

    International Nuclear Information System (INIS)

    Ma Zhenyu; Ma Guangming; Yu Haibo; Mao Dongqing; Feng Ziqiang; Hou Hongtao; Liu Jianfei

    2009-01-01

    A third harmonic superconducting niobium cavity has been proposed for installation in the Shanghai Synchrotron Radiation Facility (SSRF) storage ring to improve the Touschek lifetime. In order to investigate the feasibility of the superconducting cavity fabrication indigenously and the possibility to master the fabrication techniques, cavities were fabricated from copper and niobium sheets by deep drawing and electron-beam welding, and a series of measurements, such as resonant frequency, shape dimensions and wall thickness, were carried out during this process. After analysis of various problems existing in the fabrication process, technique improvements were proposed, and finally the precise shape as designed and resonant frequency within 1.2 MHz were achieved for the new completed cavities. In addition, full annealing was finally proved to be a good cure for niobium sheets' tearing up during deep drawing. By fabricating niobium cavities successfully, some problems to the next step were cleared. This paper introduces the process of cavity fabrication and its technique improvements towards forming, and the initial vertical test result of niobium cavity is also presented. (authors)

  14. Study of a cylindrical cavity gyrotron, influence of power reflection and of the oscillation of a travelling mode

    International Nuclear Information System (INIS)

    Muggli, P.

    1991-11-01

    The quality factor and oscillating mode of a gyrotron cavity are essential parameters to consider when trying to obtain a high power (>500 kW), high efficiency (∼50%) microwave source, which oscillates in a stable manner in the principal mode of the cavity. The study and development of an 8 GHz gyrotron whose resonant cavity is formed by a cylindrical waveguide of slowly varying radius, is undertaken. The study is principally concerned with the phenomena associated with the low quality factor of the TE o 011 mode of the cavity. (author) figs., tabs., 102 refs

  15. Thermal conditions within tree cavities in ponderosa pine (Pinus ponderosa) forests: potential implications for cavity users

    Science.gov (United States)

    Vierling, Kerri T.; Lorenz, Teresa J.; Cunningham, Patrick; Potterf, Kelsi

    2017-11-01

    Tree cavities provide critical roosting and breeding sites for multiple species, and thermal environments in these cavities are important to understand. Our objectives were to (1) describe thermal characteristics in cavities between June 3 and August 9, 2014, and (2) investigate the environmental factors that influence cavity temperatures. We placed iButtons in 84 different cavities in ponderosa pine (Pinus ponderosa) forests in central Washington, and took hourly measurements for at least 8 days in each cavity. Temperatures above 40 °C are generally lethal to developing avian embryos, and 18% of the cavities had internal temperatures of ≥ 40 °C for at least 1 h of each day. We modeled daily maximum cavity temperature, the amplitude of daily cavity temperatures, and the difference between the mean internal cavity and mean ambient temperatures as a function of several environmental variables. These variables included canopy cover, tree diameter at cavity height, cavity volume, entrance area, the hardness of the cavity body, the hardness of the cavity sill (which is the wood below the cavity entrance which forms the barrier between the cavity and the external environment), and sill width. Ambient temperature had the largest effect size for maximum cavity temperature and amplitude. Larger trees with harder sills may provide more thermally stable cavity environments, and decayed sills were positively associated with maximum cavity temperatures. Summer temperatures are projected to increase in this region, and additional research is needed to determine how the thermal environments of cavities will influence species occupancy, breeding, and survival.

  16. Dynamic control of chaotic resonators

    KAUST Repository

    Di Falco, A.

    2016-02-16

    We report on the all-optical control of chaotic optical resonators based on silicon on insulator (SOI) platform. We show that simple non-chaotic cavities can be tuned to exhibit chaotic behavior via intense optical pump- ing, inducing a local change of refractive index. To this extent we have fabricated a number of devices and demonstrated experimentally and theoretically that chaos can be triggered on demand on an optical chip. © 2016 SPIE.

  17. A digital closed loop control system for automatic phase locking of superconducting cavities of IUAC Linac

    International Nuclear Information System (INIS)

    Dutt, R.N.; Rai, A.; Pandey, A.; Sahu, B.K.; Patra, P.; Karmakar, J.; Chaudhari, G.K.; Mathur, Y.; Ghosh, S.; Kanjilal, D.

    2013-01-01

    A closed loop digital control system has been designed and tested to automate the tuning process of superconducting resonators of LINAC at Inter-University Accelerator Centre, New Delhi. The mechanism controls the proportional valves of the He gas based pneumatic tuner in response to the phase and frequency errors of the cavity RF field. The main RF phase lock loop (PLL) is automatically closed once the resonant frequency is within locking range of the resonator PLL. The digital control scheme was successfully tested on few resonators of LINAC cryostat 1. A high stability of phase lock was observed. The details of the digital automation system are presented in the paper. (author)

  18. Magnetostatic wave tunable resonators

    Science.gov (United States)

    Castera, J.-P.; Hartemann, P.

    1983-06-01

    Theoretical principles and techniques for the implementation of magnetostatic surface wave and volume wave resonators in high frequency oscillators are discussed. Magnetostatic waves are magnetic waves that propagate in materials exposed to a polarized magnetic field. The propagation speed ranges from 3-300 km/sec for wavelengths between 1 micron and 10 mm, in the presence of lags from 10-1000 nsec/ cm. Tunable resonators in the 1-20 GHz frequency range have been manufactured with YIG using liquid phase epitaxy for deposition on gadolinium and gallium substrates. Distributed-mirror Fabry-Perot cavity resonators are described and performance tests results are reported, including losses of 8 dB, a quality coefficient under voltage of 450, and frequency rejection outside of resonance better than 10 dB. However, saturation occurs at low power levels at frequencies lower than 4.2 GHz, a feature overcome with forward volume magnetostatic wave generators, which have a quality factor of 500, an insertion loss of 22 dB, and rejection around 15 dB.

  19. Cavity QED with atomic mirrors

    Science.gov (United States)

    Chang, D. E.; Jiang, L.; Gorshkov, A. V.; Kimble, H. J.

    2012-06-01

    A promising approach to merge atomic systems with scalable photonics has emerged recently, which consists of trapping cold atoms near tapered nanofibers. Here, we describe a novel technique to achieve strong, coherent coupling between a single atom and photon in such a system. Our approach makes use of collective enhancement effects, which allow a lattice of atoms to form a high-finesse cavity within the fiber. We show that a specially designated ‘impurity’ atom within the cavity can experience strongly enhanced interactions with single photons in the fiber. Under realistic conditions, a ‘strong coupling’ regime can be reached, wherein it becomes feasible to observe vacuum Rabi oscillations between the excited impurity atom and a single cavity quantum. This technique can form the basis for a scalable quantum information network using atom-nanofiber systems.

  20. A SURVEY OF CORONAL CAVITY DENSITY PROFILES

    International Nuclear Information System (INIS)

    Fuller, J.; Gibson, S. E.

    2009-01-01

    Coronal cavities are common features of the solar corona that appear as darkened regions at the base of coronal helmet streamers in coronagraph images. Their darkened appearance indicates that they are regions of lowered density embedded within the comparatively higher density helmet streamer. Despite interfering projection effects of the surrounding helmet streamer (which we refer to as the cavity rim), Fuller et al. have shown that under certain conditions it is possible to use a Van de Hulst inversion of white-light polarized brightness (pB) data to calculate the electron density of both the cavity and cavity rim plasma. In this article, we apply minor modifications to the methods of Fuller et al. in order to improve the accuracy and versatility of the inversion process, and use the new methods to calculate density profiles for both the cavity and cavity rim in 24 cavity systems. We also examine trends in cavity morphology and how departures from the model geometry affect our density calculations. The density calculations reveal that in all 24 cases the cavity plasma has a flatter density profile than the plasma of the cavity rim, meaning that the cavity has a larger density depletion at low altitudes than it does at high altitudes. We find that the mean cavity density is over four times greater than that of a coronal hole at an altitude of 1.2 R sun and that every cavity in the sample is over twice as dense as a coronal hole at this altitude. Furthermore, we find that different cavity systems near solar maximum span a greater range in density at 1.2 R sun than do cavity systems near solar minimum, with a slight trend toward higher densities for systems nearer to solar maximum. Finally, we found no significant correlation of cavity density properties with cavity height-indeed, cavities show remarkably similar density depletions-except for the two smallest cavities that show significantly greater depletion.

  1. High-quality-factor planar optical cavities with laterally stopped, slowed, or reversed light.

    Science.gov (United States)

    Byrnes, Steven J; Khorasaninejad, Mohammadreza; Capasso, Federico

    2016-08-08

    In a planar optical cavity, the resonance frequencies increase as a function of in-plane wavevector according to a standard textbook formula. This has well-known consequences in many different areas of optics, from the shifts of etalon peaks at non-normal angles, to the properties of transverse modes in laser diodes, to the effective mass of microcavity photons, and so on. However, this standard formula is valid only when the reflection phase of each cavity mirror is approximately independent of angle. There is a certain type of mirror-a subwavelength dielectric grating near a guided mode resonance-with not only a strongly angle-dependent reflection phase, but also very high reflectance and low losses. Simulations show that by using such mirrors, high-quality-factor planar cavities can be designed that break all these textbook rules, leading to resonant modes that are slow, stopped or even backward-propagating in the in-plane direction. In particular, we demonstrate experimentally high-Q planar cavities whose resonance frequency is independent of in-plane wavevector-i.e., the resonant modes have zero in-plane group velocity, for one polarization but both in-plane directions. We discuss potential applications in various fields including lasers, quantum optics, and exciton-polariton condensation.

  2. Coeliac cavity ultrasonic diagnosis apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Ando, O.; Suwaki, T.

    1983-07-05

    A coeliac cavity ultrasonic diagnosis apparatus is disclosed which includes an ultrasonic transducer or scanner portion adapted to be inserted into a coeliac cavity to effect a sector scan of an ultrasonic beam to produce an ultrasonic image of internal tissues and in which the ultrasonic oscillator on the one hand and an ultrasonic reflecting mirror and rotary disc on the other hand are relatively rotated so as to effect the sector scan of the ultrasonic beam and the rotary angle of the rotary disc is detected so as to obtain a deflecting angle of the ultrasonic beam and a display on a cathode ray tube of a precise ultrasonic picture image.

  3. Protein dynamics: hydration and cavities

    Directory of Open Access Journals (Sweden)

    Heremans K.

    2005-01-01

    Full Text Available The temperature-pressure behavior of proteins seems to be unique among the biological macromolecules. Thermodynamic as well as kinetic data show the typical elliptical stability diagram. This may be extended by assuming that the unfolded state gives rise to volume and enthalpy-driven liquid-liquid transitions. A molecular interpretation follows from the temperature and the pressure dependence of the hydration and cavities. We suggest that positron annihilation spectroscopy can provide additional quantitative evidence for the contributions of cavities to the dynamics of proteins. Only mature amyloid fibrils that form from unfolded proteins are very resistant to pressure treatment.

  4. Flat sources for active acoustic shielding based on distributed control of a vibrating plate coupled with a thin cavity

    NARCIS (Netherlands)

    Berkhoff, Arthur P.; Ho, J.

    2013-01-01

    Air cavities between plates are often used to improve noise insulation by passive means, especially at high frequencies. Such configurations may suffer from resonances, such as due to the mass-air-mass resonance. Lightweight structures, which tend to be undamped, may suffer from structural

  5. An inductively heated hot cavity catcher laser ion source

    CERN Document Server

    Reponen, M; Pohjalainen, I; Rothe, S; Savonen, M; Sonnenschein, V; Voss, A

    2015-01-01

    An inductively heated hot cavity catcher has been constructed for the production of low-energy ion beams of exotic, neutron-deficient Agisotopes. A proof-of-principle experiment has been realized by implanting primary 107Ag21+ ions from a heavy-ion cyclotron into a graphite catcher. A variable-thickness nickel foil was used to degrade the energy of the primary beam in order to mimic the implantation depth expected from the heavy-ion fusion-evaporation recoils of N = Z94Ag. Following implantation, the silver atoms diffused out of the graphite and effused into the catcher cavity and transfer tube, where they were resonantly laser ionized using a three-step excitation and ionization scheme. Following mass separation, the ions were identified by scanning the frequency of the first resonant excitation step while recording the ion count rate. Ion release time profiles were measured for different implantation depths and cavity temperatures with the mean delay time varying from 10 to 600 ms. In addition, the diffusio...

  6. The ADMX Sidecar cavity and receiver-chain

    Science.gov (United States)

    Boutan, Christian; ADMX Collaboration

    2015-04-01

    The Axion Dark Matter eXperiment (ADMX) searches for dark-matter axions by looking for their resonant conversion to microwave photons in a strong magnetic field. If ADMX rules out axions in the 500 MHz - 2 GHz frequency range, new technologies and cavity geometries will need to be explored to find higher mass axions. ADMX Sidecar is a higher frequency pathfinder experiment that uses a miniature resonant cavity to search for axions in the 2 GHz - 10 GHz frequency range. The Sidecar cavity shares the magnetic field and cryogenics of the main experiment but the data pipeline and receiver-chain are new and independent of the existing infrastructure. Unlike the main experiment, which uses gear-boxes and fiberglass shafts to translate the motion of room temperature motors into the cryogenic space, piezoelectric motors are used to adjust the Sidecar tuning rod position and antenna depth. Here I discuss the design, construction and status of ADMX Sidecar. Supported by DOE Grants DE-FG02-97ER41029, DE-FG02-96ER40956, DE- AC52-07NA27344, DE-AC03-76SF00098, NSF Grant 1067242, and the Livermore LDRD program.

  7. Snake resonances

    International Nuclear Information System (INIS)

    Tepikian, S.

    1989-01-01

    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

  8. Multiphoton resonances

    International Nuclear Information System (INIS)

    Shore, B.W.

    1977-01-01

    The long-time average of level populations in a coherently-excited anharmonic sequence of energy levels (e.g., an anharmonic oscillator) exhibits sharp resonances as a function of laser frequency. For simple linearly-increasing anharmonicity, each resonance is a superposition of various multiphoton resonances (e.g., a superposition of 3, 5, 7, . . . photon resonances), each having its own characteristic width predictable from perturbation theory

  9. HOM identification by bead pulling in the Brookhaven ERL cavity

    CERN Document Server

    Hahn, H; Jain, Puneet; Johnson, Elliott C; Xu, Wencan

    2014-01-01

    Exploratory measurements of the Brookhaven Energy Recovery Linac (ERL) cavity at superconducting temperature produced a long list of high order modes (HOMs). The niobium 5-cell cavity is terminated at each end with HOM ferrite dampers that successfully reduce the Q-factors to levels required to avoid beam break up (BBU) instabilities. However, a number of un-damped resonances with Q≥106 were found at 4 K and their mode identification forms the focus of this paper. The approach taken here consists of bead pulling on a copper (Cu) replica of the ERL cavity with dampers involving various network analyzer measurements. Several different S21 transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, others between beam-position monitor probes in the beam tubes, and also between probes placed into the cells. The bead pull technique suitable for HOM identification with a metallic needle or dielectric bead is detailed. This paper presents the...

  10. A 3D printed superconducting aluminium microwave cavity

    International Nuclear Information System (INIS)

    Creedon, Daniel L.; Goryachev, Maxim; Kostylev, Nikita; Tobar, Michael E.; Sercombe, Timothy B.

    2016-01-01

    3D printing of plastics, ceramics, and metals has existed for several decades and has revolutionized many areas of manufacturing and science. Printing of metals, in particular, has found a number of applications in fields as diverse as customized medical implants, jet engine bearings, and rapid prototyping in the automotive industry. Although many techniques are used for 3D printing metals, they commonly rely on computer controlled melting or sintering of a metal alloy powder using a laser or electron beam. The mechanical properties of parts produced in such a way have been well studied, but little attention has been paid to their electrical properties. Here we show that a microwave cavity (resonant frequencies 9.9 and 11.2 GHz) 3D printed using an Al-12Si alloy exhibits superconductivity when cooled below the critical temperature of aluminium (1.2 K), with a performance comparable with the common 6061 alloy of aluminium. Superconducting cavities find application in numerous areas of physics, from particle accelerators to cavity quantum electrodynamics experiments. The result is achieved even with a very large concentration of non-superconducting silicon in the alloy of 12.18%, compared with Al-6061, which has between 0.4% and 0.8%. Our results may pave the way for the possibility of 3D printing superconducting cavity configurations that are otherwise impossible to machine.

  11. Active Control of Flow-Induced Cavity Oscillations

    Science.gov (United States)

    Garg, Sanjay; Cattafesta, Louis N., III; Chung Won, Chin

    1996-11-01

    The interaction between a cavity and the shear layer spanning its mouth can result in the generation of high levels of tonal acoustic disturbances. The excitation and growth of instabilities in the shear layer is a fundamental part of this phenomenon. Control of such shear layer instabilities was attempted in a resonant cavity flow by actuating piezoelectric flaps at the leading edge of the cavity. Under natural flow conditions, a sound pressure level (SPL) of 140 dB was measured on the cavity floor; use of the actuators resulted in a 12 dB reduction in broadband SPL. In addition, the magnitude of the primary tone was attenuated by almost 25 dB. Detailed hot-wire measurements of instability growth and flow visualization will be presented for both the uncontrolled and controlled cases. The mean flow profile changes from that of a turbulent boundary layer at separation to one representative of a self-similar shear layer further downstream; this exerts significant influence on the development of the measured u^' eigenmode profile. An initial region of exponential growth is observed followed by a region in which nonlinear effects become important resulting in finite amplitude equilibration of disturbances. In the controlled case, nonlinear mode competition appears to determine the overall amplification experienced by any one mode. Experimental results will be compared with linear and nonlinear stability theory.

  12. New developed cylindrical TM010 mode EPR cavity for X-band in vivo tooth dosimetry.

    Directory of Open Access Journals (Sweden)

    Guo Junwang

    Full Text Available EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity's cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed. Theoretical calculations and simulations were used to design and optimize the cavity parameters. The cavity features were evaluated by measuring DPPH sample, intact incisor samples embed in a gum model and the rhesus monkey teeth. The results showed that the cavity worked at designed frequency and had the ability to make EPR spectroscopy in relative high sensitivity. Sufficient modulation amplitude and microwave power could be applied into the aperture. Radiation induced EPR signal could be observed remarkably from 1 Gy irradiated intact incisor within only 30 seconds, which was among the best in scan time and detection limit. The in vivo spectroscopy was also realized by acquiring the radiation induced EPR signal from teeth of rhesus monkey whose teeth was irradiated by dose of 2 Gy. The results suggested that the cavity was sensitive to meet the demand to assess doses of significant level in short time. This cavity provided a very potential option for the development of X-band in vivo dosimetry.

  13. Effect of Sweep on Cavity Flow Fields at Subsonic and Transonic Speeds

    Science.gov (United States)

    Tracy, Maureen B.; Plentovich, Elizabeth B.; Hemsch, Michael J.; Wilcox, Floyd J.

    2012-01-01

    An experimental investigation was conducted in the NASA Langley 7 x 10-Foot High Speed Tunnel (HST) to study the effect of leading- and trailing-edge sweep on cavity flow fields for a range of cavity length-to-height (l/h) ratios. The free-stream Mach number was varied from 0.2 to 0.8. The cavity had a depth of 0.5 inches, a width of 2.5 inches, and a maximum length of 12.0 inches. The leading- and trailing-edge sweep was adjusted using block inserts to achieve leading edge sweep angles of 65 deg, 55 deg, 45 deg, 35 deg, and 0 deg. The fore and aft cavity walls were always parallel. The aft wall of the cavity was remotely positioned to achieve a range of length-to-depth ratios. Fluctuating- and static-pressure data were obtained on the floor of the cavity. The fluctuating pressure data were used to determine whether or not resonance occurred in the cavity rather than to provide a characterization of the fluctuating pressure field. Qualitative surface flow visualization was obtained using a technique in which colored water was introduced into the model through static-pressure orifices. A complete tabulation of the mean static-pressure data for the swept leading edge cavities is included.

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

    OpenAIRE

    Jankovic, Nikolina; Cselyuszka, Norbert

    2018-01-01

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

  15. Conduction cooling systems for linear accelerator cavities

    Science.gov (United States)

    Kephart, Robert

    2017-05-02

    A conduction cooling system for linear accelerator cavities. The system conducts heat from the cavities to a refrigeration unit using at least one cavity cooler interconnected with a cooling connector. The cavity cooler and cooling connector are both made from solid material having a very high thermal conductivity of approximately 1.times.10.sup.4 W m.sup.-1 K.sup.-1 at temperatures of approximately 4 degrees K. This allows for very simple and effective conduction of waste heat from the linear accelerator cavities to the cavity cooler, along the cooling connector, and thence to the refrigeration unit.

  16. Hybrid Vertical-Cavity Laser

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention provides a light source (2) for light circuits on a silicon platform (3). A vertical laser cavity is formed by a gain region (101) arranged between a top mirror (4) and a bottom grating-mirror (12) in a grating region (11) in a silicon layer (10) on a substrate. A waveguide ...

  17. "Grinding" cavities in polyurethane foam

    Science.gov (United States)

    Brower, J. R.; Davey, R. E.; Dixon, W. F.; Robb, P. H.; Zebus, P. P.

    1980-01-01

    Grinding tool installed on conventional milling machine cuts precise cavities in foam blocks. Method is well suited for prototype or midsize production runs and can be adapted to computer control for mass production. Method saves time and materials compared to bonding or hot wire techniques.

  18. On the collapse of cavities

    Science.gov (United States)

    Bourne, N. K.

    The collapse of a single cavity, or a cloud of bubbles has several physical consequences when in proximity to a structure or resident within a material during deformation. The earliest recognized of these was cavitation erosion of the propellers of steam ships. However, other processes include the rapid collapse of cavities leading to hot spots in explosives from which reaction ensues, or the more recent phenomenon of light generation by oscillating single bubbles or clouds. In the collapse of a cavity, the least considered but the most important mechanism is asymmetric closure. One of the consequences of this is the formation of jets leading to local high pressures and shears that result in the damage or reaction mechanisms observed. The challenge for the future remains in understanding the effects of cloud cavitation since it is likely that only one bubble in perhaps millions in a cloud catalyses an event. The review follows the author's work in the understanding of shock-induced cavity collapse and highlights several results which indicate the importance of this problem in a variety of fields.

  19. A 200 MHz prebunching cavity

    CERN Multimedia

    1977-01-01

    This cavity was installed in the PS ring and proved very efficient in providing a modulation on the PS beam before it is injected into the SPS machine. Moreover it allowed longitudinal instabilities studies at high intensities. Roberto Cappi stands on the left.

  20. Improving cooling of cavity blackbodies

    Science.gov (United States)

    Barrat, Catherine; Chauvel, Gildas

    2013-10-01

    A cavity blackbody is the appropriate IR reference source for IR sensors which require high radiance levels. It combines high emissivity independent from wavelength and high speed warm up and high stability thanks to its light trap structure. However, the inconvenient of this structure is that it leads to a prohibitive cooling time. HGH developed a method to speed up the cooling time.

  1. 849 RESONANCE | September 2013

    Indian Academy of Sciences (India)

    IAS Admin

    849. RESONANCE | September 2013. Page 2. 850. RESONANCE | September 2013. Page 3. 851. RESONANCE | September 2013. Page 4. 852. RESONANCE | September 2013. Page 5. 853. RESONANCE | September 2013. Page 6. 854. RESONANCE | September 2013. Page 7. 855. RESONANCE | September 2013.

  2. Tailoring Multiqubit Measurement Operators Through Dynamic Cavity States (Part 1)

    Science.gov (United States)

    Blumoff, J.; Chou, K.; Nigg, S.; Reed, M.; Vlastakis, B.; Heeres, R.; Frunzio, L.; Girvin, S.; Devoret, M. H.; Schoelkopf, R. J.

    2014-03-01

    Recent improvements in resonator coherence times in the field of superconducting qubits have allowed access to a rich new toolbox which takes advantage of their large and long-lived Hilbert space. In this talk, I introduce several techniques utilizing the cavity state and protocols built from these techniques. We condition the evolution of a cavity state via dispersive interactions with multiple qubits, and manipulate the system to implement quantum erasure, selectively reducing the space of the resulting entanglement. This can be tailored to create a spectrum of measurement operators including measurements on a selectable subset of the system. This ability is a prerequisite for most approaches to quantum error correction. The following talk will cover the experimental implementation. Work supported by IARPA and ARO.

  3. HOM Coupler Optimisation for the Superconducting RF Cavities in ESS

    CERN Document Server

    Ainsworth, R; Calaga, R

    2012-01-01

    The European Spallation Source (ESS) will be the world’s most powerful next generation neutron source. It consists of a linear accelerator, target, and instruments for neutron experiments. The linac is designed to accelerate protons to a final energy of 2.5 GeV, with an average design beam power of 5 MW, for collision with a target used to produce a high neutron flux. A section of the linac will contain Superconducting RF (SCRF) cavities designed at 704 MHz. Beam induced HOMs in these cavities may drive the beam unstable and increase the cryogenic load, therefore HOM couplers are installed to provide sufficient damping. Previous studies have shown that these couplers are susceptible to multipacting, a resonant process which can absorb RF power and lead to heating effects. This paper will show how a coupler suffering from multipacting has been redesigned to limit this effect. Optimisation of the RF damping is also discussed.

  4. Negative differential resistance in Josephson junctions coupled to a cavity

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Filatrella, G.; Pierro, V.

    2014-01-01

    Regions with negative differential resistance can arise in the IV curve of Josephson junctions and this phenomenon plays an essential role for applications, in particular for THz radiation emission. For the measurement of high frequency radiation from Josephson junctions, a cavity – either internal...... or external – is often used. A cavity may also induce a negative differential resistance region at the lower side of the resonance frequency. We investigate the dynamics of Josephson junctions with a negative differential resistance in the quasi particle tunnel current, i.e. in the McCumber curve. We find...... that very complicated and unexpected interactions take place. This may be useful for the interpretation of experimental measurements of THz radiation from intrinsic Josephson junctions....

  5. Design and construction of superconductor resonators

    International Nuclear Information System (INIS)

    Ben-Zvi, I.; Goliak, T.; Holmgren, D.W.; Storm, D.W.

    1984-01-01

    A low beta resonator was fabricated at the Nuclear Physics Laboratory, then plated and successfully tested at Stony Brook. The basic design is a quarter wave, cylindrical cavity excited by a magnetic coupling loop. Before the copper prototype was made the exact design parameters were measured by the construction and RF testing of a brass model

  6. Plasmonic-cavity model for radiating nano-rod antennas

    DEFF Research Database (Denmark)

    Peng, Liang; Mortensen, N. Asger

    2014-01-01

    In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition and the ......In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition...... and the radiation efficiency. With our theoretical model, we show that besides the plasmonic resonances, efficient radiation takes advantage of (a) rendering a large value of the rods' radius and (b) a central-fed profile, through which the radiation efficiency can reach up to 70% and even higher in a wide...... frequency band. Our theoretical expressions and conclusions are general and pave the way for engineering and further optimization of optical antenna systems and their radiation patterns....

  7. Frequency-feedback tuning for single-cell cavity under rf heating

    International Nuclear Information System (INIS)

    Stepp, J.D.; Bridges, J.F.

    1993-01-01

    A tuning system is described that is being used to match the source frequency of a high-power klystron on the resonant frequency of the prototype single-cell cavity for the 7-GeV Advance Photon Source (APS) storage ring. Typically a water-cooled piston tuner is required to adjust the reactive component of the cavity's impedance to minimize reflected power back to the RF drive source. As the cavity watts expand due to RF heating, the resonant frequency decreases. Adjusting the source frequency to follow the cavity resonant frequency is a convenient method used to condition the cavity (for vacuum) at high power levels, in this case, 1 MV gap voltage at 100 kW power level. The tuning system consists of two coupling ports, a phase detector, a digitizing I/O system, and a DC coupled FM-modulated RF source. Proportional Integral Derivative (PID) loop parameters for the Experimental Physics and Industrial Control System (EPICS) software are calculated, and data is presented showing the damped response to peturbations on the loop. The timing system presented here does not need water-cooling, has no moving parts to wear out, and has an inherently faster response time. Its one limitation is the digitizing sampling rate. The only limitation in tuning range is the bandwidth of the RF source

  8. Study of additive manufactured microwave cavities for pulsed optically pumped atomic clock applications

    Science.gov (United States)

    Affolderbach, C.; Moreno, W.; Ivanov, A. E.; Debogovic, T.; Pellaton, M.; Skrivervik, A. K.; de Rijk, E.; Mileti, G.

    2018-03-01

    Additive manufacturing (AM) of passive microwave components is of high interest for the cost-effective and rapid prototyping or manufacture of devices with complex geometries. Here, we present an experimental study on the properties of recently demonstrated microwave resonator cavities manufactured by AM, in view of their applications to high-performance compact atomic clocks. The microwave cavities employ a loop-gap geometry using six electrodes. The critical electrode structures were manufactured monolithically using two different approaches: Stereolithography (SLA) of a polymer followed by metal coating and Selective Laser Melting (SLM) of aluminum. The tested microwave cavities show the desired TE011-like resonant mode at the Rb clock frequency of ≈6.835 GHz, with a microwave magnetic field highly parallel to the quantization axis across the vapor cell. When operated in an atomic clock setup, the measured atomic Rabi oscillations are comparable to those observed for conventionally manufactured cavities and indicate a good uniformity of the field amplitude across the vapor cell. Employing a time-domain Ramsey scheme on one of the SLA cavities, high-contrast (34%) Ramsey fringes are observed for the Rb clock transition, along with a narrow (166 Hz linewidth) central fringe. The measured clock stability of 2.2 × 10-13 τ-1/2 up to the integration time of 30 s is comparable to the current state-of-the-art stabilities of compact vapor-cell clocks based on conventional microwave cavities and thus demonstrates the feasibility of the approach.

  9. Waveguide based external cavity semiconductor lasers

    NARCIS (Netherlands)

    Oldenbeuving, Ruud; Klein, E.J.; Offerhaus, Herman L.; Lee, Christopher James; Verhaegen, M.; Boller, Klaus J.

    2012-01-01

    We report on progress of the project waveguide based external cavity semiconductor laser (WECSL) arrays. Here we present the latest results on our efforts to mode lock an array of tunable, external cavity semiconductor lasers.

  10. Optical cavity furnace for semiconductor wafer processing

    Science.gov (United States)

    Sopori, Bhushan L.

    2014-08-05

    An optical cavity furnace 10 having multiple optical energy sources 12 associated with an optical cavity 18 of the furnace. The multiple optical energy sources 12 may be lamps or other devices suitable for producing an appropriate level of optical energy. The optical cavity furnace 10 may also include one or more reflectors 14 and one or more walls 16 associated with the optical energy sources 12 such that the reflectors 14 and walls 16 define the optical cavity 18. The walls 16 may have any desired configuration or shape to enhance operation of the furnace as an optical cavity 18. The optical energy sources 12 may be positioned at any location with respect to the reflectors 14 and walls defining the optical cavity. The optical cavity furnace 10 may further include a semiconductor wafer transport system 22 for transporting one or more semiconductor wafers 20 through the optical cavity.

  11. Plasmon filters and resonators in metal-insulator-metal waveguides.

    Science.gov (United States)

    Neutens, P; Lagae, L; Borghs, G; Van Dorpe, P

    2012-02-13

    We present the numerical and experimental demonstration of plasmonic Bragg filters and resonators inside metal-insulator-metal (MIM) waveguides. The presented filters and resonators are fabricated using standard top down lithography methods. The optical bandgap of the integrated Bragg filters is experimentally observed and its optical properties are investigated as a function of the grating pitch and the number of grating periods. Transmission filters based on a nanocavity resonance were measured, obtaining Q-factors above 30. Tuning of the cavity wavelength was experimentally achieved by varying the cavity length.

  12. Cavity quantum electrodynamics with charge-controlled quantum dots coupled to a fiber Fabry–Perot cavity

    International Nuclear Information System (INIS)

    Miguel-Sánchez, Javier; Reinhard, Andreas; Togan, Emre; Volz, Thomas; Imamoglu, Atac; Besga, Benjamin; Reichel, Jakob; Estève, Jérôme

    2013-01-01

    We demonstrate non-perturbative coupling between a single self-assembled InGaAs quantum dot and an external fiber-mirror-based microcavity. Our results extend the previous realizations of tunable microcavities while ensuring spatial and spectral overlap between the cavity mode and the emitter by simultaneously allowing for deterministic charge control of the quantum dots. Using resonant spectroscopy, we show that the coupled quantum dot cavity system is at the onset of strong coupling, with a cooperativity parameter of C ≈ 2.0 ± 1.3. Our results constitute a milestone in the progress toward the realization of a high-efficiency solid-state spin–photon interface. (paper)

  13. Lateral acoustic wave resonator comprising a suspended membrane of low damping resonator material

    Science.gov (United States)

    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.

  14. An economical wireless cavity-nest viewer

    Science.gov (United States)

    Daniel P. Huebner; Sarah R. Hurteau

    2007-01-01

    Inspection of cavity nests and nest boxes is often required during studies of cavity-nesting birds, and fiberscopes and pole-mounted video cameras are sometimes used for such inspection. However, the cost of these systems may be prohibitive for some potential users. We describe a user-built, wireless cavity viewer that can be used to access cavities as high as 15 m and...

  15. Cavity QED experiments with ion Coulomb crystals

    DEFF Research Database (Denmark)

    Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan

    2009-01-01

    Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained.......Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained....

  16. IMPLEMENTATION OF A TUNING SYSTEM FOR HELMHOLTZ RESONATOR ARRAYS IN A HVAC DUCT

    OpenAIRE

    寺尾, 道仁; Terao, Michihito; 関根, 秀久; Sekine, Hidehisa; 鈴木, 誠人; Suzuki, Masato

    2010-01-01

    Onsite tuning is mandatory to utilize Helmholtz resonators for HVAC ducts. However, no tuning device or general-use system is yet available, and engineers have thus been avoiding the use of such resonators. The objective of this study is to develop a tuning system for resonator arrays for HVAC ducts. We employed the cavity volume, resonator neck resistanceand neck open area as control parameters to tune the resonance frequency, resonancesharpness and sound dissipation factor, respectively. To...

  17. Two-channel interaction models in cavity QED

    International Nuclear Information System (INIS)

    Wang, L.

    1993-01-01

    The authors introduce four fully quantized models of light-matter interactions in optical or microwave cavities. These are the first exactly soluble models in cavity quantum electrodynamics (cavity QED) that provide two transition channels for the flipping of atomic states. In these models a loss-free cavity is assumed to support three or four quantized field modes, which are coupled to a single atom. The atom exchanges photons with the cavity, in either the Raman configuration including both Stokes and anti-Stokes modes, or through two-photon cascade processes. The authors obtain the effective Hamiltonians for these models by adiabatically eliminating an off-resonant intermediate atomic level, and discuss their novel properties in comparison to the existing one-channel Jaynes-Cummings models. They give a detailed description of a method to find exact analytic solutions for the eigenfunctions and eigenvalues for the Hamiltonians of four models. These are also valid when the AC Stark shifts are included. It is shown that the eigenvalues can be expressed in very simple terms, and formulas for normalized eigenvectors are also given, as well as discussions of some of their simple properties. Heisenberg picture equations of motions are derived for several operators with solutions provided in a couple of cases. The dynamics of the systems with both Fock state and coherent state fields are demonstrated and discussed using the model's two key variables, the atomic inversion and the expectation value of photon number. Clear evidences of high efficiency mode-mixing are seen in both the Raman and cascade configurations, and different kinds of collapses and revivals are encountered in the atomic inversions. Effects of several factors like the AC Stark shift and variations in the complex coupling constants are also illustrated

  18. Frequency dependence of the acoustic field generated from a spherical cavity transducer with open ends

    Directory of Open Access Journals (Sweden)

    Faqi Li

    2015-12-01

    Full Text Available Resolution of high intensity focused ultrasound (HIFU focusing is limited by the wave diffraction. We have developed a spherical cavity transducer with two open ends to improve the focusing precision without sacrificing the acoustic intensity (App Phys Lett 2013; 102: 204102. This work aims to theoretically and experimentally investigate the frequency dependence of the acoustic field generated from the spherical cavity transducer with two open ends. The device emits high intensity ultrasound at the frequency ranging from 420 to 470 kHz, and the acoustic field is measured by a fiber optic probe hydrophone. The measured results shows that the spherical cavity transducer provides high acoustic intensity for HIFU treatment only in its resonant modes, and a series of resonant frequencies can be choosen. Furthermore, a finite element model is developed to discuss the frequency dependence of the acoustic field. The numerical simulations coincide well with the measured results.

  19. Plasmon-induced transparency in sensing application with semicircle cavity waveguide

    Science.gov (United States)

    Dong, Lirong; Xu, Xuemei; Li, Chenjing; Guo, Yuan; Sun, Kehui; Ding, Yipeng

    2018-03-01

    In this paper, a plasmonic nano-sensor is proposed in semicircle cavity waveguide, the transmission characteristics of the new structure are analyzed by the finite-difference time-domain method. Dual plasmon-induced transparency (PIT) phenomenon is emerged in the semicircle cavity coupled with bus waveguide, which is resulted from the destructive interference superposition of the reflected and transmitted waves from cavity resonator. High sensitivity and figure of merit (FOM) based on PIT in the resonator has been investigated in detail. The sensitivity of the proposed model is about 2000 nm/RIU and its maximum FOM is up to 85370. In addition, dual PIT peaks are found by changing the structure parameters. The simple structure with such high sensitivity and FOM provide potential implications in nano-sensing field.

  20. Diagram of a LEP superconducting cavity

    CERN Multimedia

    1991-01-01

    This diagram gives a schematic representation of the superconducting radio-frequency cavities at LEP. Liquid helium is used to cool the cavity to 4.5 degrees above absolute zero so that very high electric fields can be produced, increasing the operating energy of the accelerator. Superconducting cavities were used only in the LEP-2 phase of the accelerator, from 1996 to 2000.

  1. Microscopic theory of phonon-induced effects on semiconductor quantum dot decay dynamics in cavity QED

    DEFF Research Database (Denmark)

    Nielsen, Per Kær; Nielsen, Torben Roland; Lodahl, P.

    2012-01-01

    We investigate the influence of the electron-phonon interaction on the decay dynamics of a quantum dot coupled to an optical microcavity. We show that the electron-phonon interaction has important consequences on the dynamics, especially when the quantum dot and cavity are tuned out of resonance...

  2. Feasibility, engineering aspects and physics reach of microwave cavity experiments searching for hidden photons and axions

    Energy Technology Data Exchange (ETDEWEB)

    Caspers, F. [CERN, Geneva (Switzerland); Jaeckel, J. [Univ. of Durham, Inst. for Particle Physics and Phenomenology (United Kingdom); Ringwald, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2009-08-15

    Using microwave cavities one can build a resonant ''light-shining-through-walls'' experiment to search for hidden sector photons and axion like particles, predicted in many extensions of the standard model. In this note we make a feasibility study of the sensitivities which can be reached using state of the art technology. (orig.)

  3. Comparison of Five Computational Methods for Computing Q Factors in Photonic Crystal Membrane Cavities

    DEFF Research Database (Denmark)

    Novitsky, Andrey; de Lasson, Jakob Rosenkrantz; Frandsen, Lars Hagedorn

    2017-01-01

    Five state-of-the-art computational methods are benchmarked by computing quality factors and resonance wavelengths in photonic crystal membrane L5 and L9 line defect cavities. The convergence of the methods with respect to resolution, degrees of freedom and number of modes is investigated. Specia...

  4. Absolute quantitation of left ventricular wall and cavity parameters using ECG-gated PET

    DEFF Research Database (Denmark)

    Freiberg, Jacob; Hove, Jens D; Kofoed, Klaus F

    2004-01-01

    in a heart phantom and in healthy subjects. Twelve healthy men aged 64 +/- 8 years were studied by use of cine magnetic resonance imaging (MRI) and ECG-gated FDG-PET during euglycemic glucose-insulin clamp. At increasing image noise levels, the estimated cavity volume of the heart phantom was within 2 m...

  5. Atom-membrane cooling and entanglement using cavity electromagnetically induced transparency

    DEFF Research Database (Denmark)

    Genes, Claudiu; Ritsch, Helmut; Drewsen, Michael

    2011-01-01

    allows for strong coupling of the membrane's mechanical oscillations to the collective atomic ground-state spin. This facilitates ground-state cooling of the membrane motion, quantum state mapping, and robust atom-membrane entanglement even for cavity widths larger than the mechanical resonance frequency....

  6. In-fiber whispering-gallery-mode resonator fabricated by femtosecond laser micromachining.

    Science.gov (United States)

    Shi, Leilei; Zhu, Tao; Huang, Dongmei; Liu, Min; Deng, Ming; Huang, Wei

    2015-08-15

    An in-fiber whispering-gallery-mode resonator fabricated by femtosecond laser micromachining is demonstrated. The cylinder resonator cavity is fabricated by scanning the D-fiber cladding with infrared femtosecond pulses along a cylindrical trace with a radius of 25 μm and height of 20 μm. Quality factor on the order of 10(3) is achieved by smoothing the cavity surface with an ultrasonic cleaner, which is mainly limited by the surface roughness of several hundred nanometers. Resonant characteristics and polarization dependence of the proposed resonator are also studied in detail. Our method takes a step forward in the integration of whispering-gallery-mode resonators.

  7. Dramatically Enhanced Spin Dynamo with Plasmonic Diabolo Cavity.

    Science.gov (United States)

    Gou, Peng; Qian, Jie; Xi, Fuchun; Zou, Yuexin; Cao, Jun; Yu, Haochi; Zhao, Ziyi; Yang, Le; Xu, Jie; Wang, Hengliang; Zhang, Lijian; An, Zhenghua

    2017-07-13

    The applications of spin dynamos, which could potentially power complex nanoscopic devices, have so far been limited owing to their extremely low energy conversion efficiencies. Here, we present a unique plasmonic diabolo cavity (PDC) that dramatically improves the spin rectification signal (enhancement of more than three orders of magnitude) under microwave excitation; further, it enables an energy conversion efficiency of up to ~0.69 mV/mW, compared with ~0.27 μV/mW without a PDC. This remarkable improvement arises from the simultaneous enhancement of the microwave electric field (~13-fold) and the magnetic field (~195-fold), which cooperate in the spin precession process generates photovoltage (PV) efficiently under ferromagnetic resonance (FMR) conditions. The interplay of the microwave electromagnetic resonance and the ferromagnetic resonance originates from a hybridized mode based on the plasmonic resonance of the diabolo structure and Fabry-Perot-like modes in the PDC. Our work sheds light on how more efficient spin dynamo devices for practical applications could be realized and paves the way for future studies utilizing both artificial and natural magnetism for applications in many disciplines, such as for the design of future efficient wireless energy conversion devices, high frequent resonant spintronic devices, and magnonic metamaterials.

  8. Gastrophysics of the Oral Cavity.

    Science.gov (United States)

    Mouritsen, Ole G

    2016-01-01

    Gastrophysics is the science that pertains to the physical and physico-chemical description of the empirical world of gastronomy, with focus on sensory perception in the oral cavity and how it is related to the materials properties of food and cooking processes. Flavor (taste and smell), mouthfeel, chemesthesis, and astringency are all related to the chemical properties and the texture of the food and how the food is transformed in the oral cavity. The present topical review will primarily focus attention on the somatosensory perception of food (mouthfeel or texture) and how it interacts with basic tastes (sour, bitter, sweet, salty, and umami) and chemesthetic action. Issues regarding diet, nutrition, and health will be put into an evolutionary perspective, and some mention will be made of umami and its importance for (oral) health.

  9. Cavity optomechanics with a nonlinear photonic-crystal nanomembrane

    International Nuclear Information System (INIS)

    Makles, Kevin; Kuhn, Aurélien; Briant, Tristan; Cohadon, Pierre-François; Heidmann, Antoine; Antoni, Thomas; Braive, Rémy; Sagnes, Isabelle; Robert-Philip, Isabelle

    2014-01-01

    We have designed, fabricated and characterized a nanomembrane which could be used as a moving end mirror of a Fabry-Perot cavity. The high reflectivity and optimized mechanical properties of the membrane should allow us to demonstrate the mechanical ground state of the membrane. As any sub-micron mechanical resonator, our system demonstrates nonlinear dynamical effects. We characterize the mechanical response to a strong pump drive and observe a shift in the oscillation frequency and phase conjugation of the mechanical mode. Such nonlinear effects are expected to play a role in the quantum dynamics of the membrane as well

  10. Multipactor simulations in superconducting cavities and power couplers

    Directory of Open Access Journals (Sweden)

    G. Devanz

    2001-01-01

    Full Text Available A new computer code for simulation of multipacting phenomenon in axisymmetrical radio frequency structures is presented. The existence of resonant electron trajectories can lead to electron multiplication under given field and surface conditions and can damage these accelerator components or prevent their use. The goal of the simulation is to detect such occurrences. Therefore, large parameter sets have to be tested; a parallel version of the code has been developed to reduce computing time while dealing with highly demanding cases in terms of accuracy and parameter sweeping. Both superconducting cavities and power coupler components have been studied. Simulation results are compared with experimental measurements.

  11. Cavity-induced mirror-mirror entanglement in a single-atom Raman laser

    Science.gov (United States)

    Teklu, Berihu; Byrnes, Tim; Khan, Faisal Shah

    2018-02-01

    We address an experimental scheme to analyze the optical bistability and the entanglement of two movable mirrors coupled to a two-mode laser inside a doubly resonant cavity. With this aim we investigate the master equations of the atom-cavity subsystem in conjunction with the quantum Langevin equations that describe the interaction of the mirror cavity. The parametric amplification-type coupling induced by the two-photon coherence on the optical bistability of the intracavity mean photon numbers is found and investigated. Under this condition, the optical intensities exhibit bistability for all large values of cavity laser detuning. We also provide numerical evidence for the generation of strong entanglement between the movable mirrors and show that it is robust against environmental thermalization.

  12. Upper-limit on the Advanced Virgo output mode cleaner cavity length noise

    Science.gov (United States)

    Bonnand, R.; Ducrot, M.; Gouaty, R.; Marion, F.; Masserot, A.; Mours, B.; Pacaud, E.; Rolland, L.; Was, M.

    2017-09-01

    The Advanced Virgo detector uses two monolithic optical cavities at its output port to suppress higher order modes and radio frequency sidebands from the carrier light used for gravitational wave detection. These two cavities in series form the output mode cleaner. We present a measured upper limit on the length noise of these cavities that is consistent with the thermo-refractive noise prediction of 8×10-16~m~Hz-1/2 at 15 Hz. The cavity length is controlled using Peltier cells and piezo-electric actuators to maintain resonance on the incoming light. A length lock precision of 3.5×10-13 m is achieved. These two results are combined to demonstrate that the broadband length noise of the output mode cleaner in the 10-60 Hz band is at least a factor 10 below other expected noise sources in the Advanced Virgo detector design configuration.

  13. Self-amplified lock of an ultra-narrow linewidth optical cavity.

    Science.gov (United States)

    Izumi, Kiwamu; Sigg, Daniel; Barsotti, Lisa

    2014-09-15

    High finesse optical cavities are an essential tool in modern precision laser interferometry. The incident laser field is often controlled and stabilized with an active feedback system such that the field resonates in the cavity. The Pound-Drever-Hall reflection locking technique is a convenient way to derive a suitable error signal. However, it only gives a strong signal within the cavity linewidth. This poses a problem for locking an ultra-narrow linewidth cavity. We present a novel technique for acquiring lock by utilizing an additional weak control signal, but with a much larger capture range. We numerically show that this technique can be applied to the laser frequency stabilization system used in the Laser Interferometric Gravitational-wave Observatory (LIGO), which has a linewidth of 0.8 Hz. This new technique will allow us to robustly and repeatedly lock the LIGO laser frequency to the common mode of the interferometer.

  14. Adaptive frequency comb illumination for interferometry in the case of nested two-beam cavities

    International Nuclear Information System (INIS)

    Harder, Irina; Leuchs, Gerd; Mantel, Klaus; Schwider, Johannes

    2011-01-01

    The homogeneity test of glass plates in a Fizeau interferometer is hampered by the superposition of multiple interference signals coming from the surfaces of the glass plate as well as the empty Fizeau cavity. To evaluate interferograms resulting from such nested cavities, various approaches such as the use of broadband light sources have been applied. In this paper, we propose an adaptive frequency comb interferometer to accomplish the cavity selection. An adjustable Fabry-Perot resonator is used to generate a variable frequency comb that can be matched to the length of the desired cavity. Owing to its flexibility, the number of measurements needed for the homogeneity test can be reduced to four. Furthermore, compared to approaches using a two-beam interferometer as a filter for the broadband light source, the visibility of the fringe system is considerably higher if a Fabry-Perot filter is applied.

  15. Long bunch trains measured using a prototype cavity beam position monitor for the Compact Linear Collider

    Directory of Open Access Journals (Sweden)

    F. J. Cullinan

    2015-11-01

    Full Text Available The Compact Linear Collider (CLIC requires beam position monitors (BPMs with 50 nm spatial resolution for alignment of the beam line elements in the main linac and beam delivery system. Furthermore, the BPMs must be able to make multiple independent measurements within a single 156 ns long bunch train. A prototype cavity BPM for CLIC has been manufactured and tested on the probe beam line at the 3rd CLIC Test Facility (CTF3 at CERN. The transverse beam position is determined from the electromagnetic resonant modes excited by the beam in the two cavities of the pickup, the position cavity and the reference cavity. The mode that is measured in each cavity resonates at 15 GHz and has a loaded quality factor that is below 200. Analytical expressions for the amplitude, phase and total energy of signals from long trains of bunches have been derived and the main conclusions are discussed. The results of the beam tests are presented. The variable gain of the receiver electronics has been characterized using beam excited signals and the form of the signals for different beam pulse lengths with the 2/3  ns bunch spacing has been observed. The sensitivity of the reference cavity signal to charge and the horizontal position signal to beam offset have been measured and are compared with theoretical predictions based on laboratory measurements of the BPM pickup and the form of the resonant cavity modes as determined by numerical simulation. Finally, the BPM was calibrated so that the beam position jitter at the BPM location could be measured. It is expected that the beam jitter scales linearly with the beam size and so the results are compared to predicted values for the latter.

  16. Resonance in a Cone-Topped Tube

    Directory of Open Access Journals (Sweden)

    Angus Cheng-Huan Chia

    2011-06-01

    Full Text Available The relationship between ratio of the upper opening diameter of a cone-topped cylinder to the cylinder diameter,and the ratio of the length of the air column to resonant period was examined. Plastic cones with upper openings ranging from 1.3 cm to 3.6 cm and tuning forks with frequencies ranging from 261.6 Hz to 523.3 Hz were used. The transition from a standing wave in a cylindrical column to a Helmholtz-type resonance in a resonant cavity with a narrow opening was observed.

  17. Synchrobetatron resonances

    International Nuclear Information System (INIS)

    1977-03-01

    At the 1975 Particle Accelerator Conference it was reported that a class of resonances were observed in SPEAR II that had not appeared before in SPEAR I. While the existence of sideband resonances of the main betatron oscillation frequencies has been previously observed and analyzed, the resonances observed in SPEAR do not appear to be of the same variety. Experiments were performed at SPEAR to identify the mechanism believed to be the most likely explanation. Some of the current experimental knowledge and theoretical views on the source of these resonances are presented

  18. Snake resonances

    International Nuclear Information System (INIS)

    Tepikian, S.

    1988-01-01

    Siberian Snakes provide a practical means of obtaining polarized proton beams in large accelerators. The effect of snakes can be understood by studying the dynamics of spin precession in an accelerator with snakes and a single spin resonance. This leads to a new class of energy independent spin depolarizing resonances, called snake resonances. In designing a large accelerator with snakes to preserve the spin polarization, there is an added constraint on the choice of the vertical betatron tune due to the snake resonances. 11 refs., 4 figs

  19. Optomechanic interactions in phoxonic cavities

    Directory of Open Access Journals (Sweden)

    Bahram Djafari-Rouhani

    2014-12-01

    Full Text Available Phoxonic crystals are periodic structures exhibiting simultaneous phononic and photonic band gaps, thus allowing the confinement of both excitations in the same cavity. The phonon-photon interaction can be enhanced due to the overlap of both waves in the cavity. In this paper, we discuss some of our recent theoretical works on the strength of the optomechanic coupling, based on both photoelastic and moving interfaces mechanisms, in different (2D, slabs, strips phoxonic crystals cavities. The cases of two-dimensional infinite and slab structures will enable us to mention the important role of the symmetry and degeneracy of the modes, as well as the role of the materials whose photoelastic constants can be wavelength dependent. Depending on the phonon-photon pair, the photoelastic and moving interface mechanisms can contribute in phase or out-of-phase. Then, the main part of the paper will be devoted to the optomechanic interaction in a corrugated nanobeam waveguide exhibiting dual phononic/photonic band gaps. Such structures can provide photonic modes with very high quality factor, high frequency phononic modes of a few GHz inside a gap and optomechanical coupling rate reaching a few MHz.

  20. Optomechanic interactions in phoxonic cavities

    Energy Technology Data Exchange (ETDEWEB)

    Djafari-Rouhani, Bahram; Oudich, Mourad; Pennec, Yan [Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, UFR de physique, Université Lille1, Cité Scientifique, 59652, Villeneuve d’Ascq (France); El-Jallal, Said [Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, UFR de physique, Université Lille1, Cité Scientifique, 59652, Villeneuve d’Ascq (France); Physique du Rayonnement et de l’Interaction Laser Matière, Faculté des sciences, Université de Moulay Ismail, Meknès (Morocco)

    2014-12-15

    Phoxonic crystals are periodic structures exhibiting simultaneous phononic and photonic band gaps, thus allowing the confinement of both excitations in the same cavity. The phonon-photon interaction can be enhanced due to the overlap of both waves in the cavity. In this paper, we discuss some of our recent theoretical works on the strength of the optomechanic coupling, based on both photoelastic and moving interfaces mechanisms, in different (2D, slabs, strips) phoxonic crystals cavities. The cases of two-dimensional infinite and slab structures will enable us to mention the important role of the symmetry and degeneracy of the modes, as well as the role of the materials whose photoelastic constants can be wavelength dependent. Depending on the phonon-photon pair, the photoelastic and moving interface mechanisms can contribute in phase or out-of-phase. Then, the main part of the paper will be devoted to the optomechanic interaction in a corrugated nanobeam waveguide exhibiting dual phononic/photonic band gaps. Such structures can provide photonic modes with very high quality factor, high frequency phononic modes of a few GHz inside a gap and optomechanical coupling rate reaching a few MHz.

  1. Status of the ILC Crab Cavity Development

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Dexter, A.; /Cockcroft Inst. Accel. Sci. Tech.; Beard, C.; Goudket, P.; McIntosh, P.; /Daresbury; Bellantoni, L.; /Fermilab; Grimm, T.; Li, Z.; Xiao, L.; /SLAC

    2011-10-20

    The International Linear Collider (ILC) will require two dipole cavities to 'crab' the electron and positron bunches prior to their collision. It is proposed to use two 9 cell SCRF dipole cavities operating at a frequency of 3.9 GHz, with a transverse gradient of 3.8MV/m in order to provide the required transverse kick. Extensive numerical modelling of this cavity and its couplers has been performed. Aluminium prototypes have been manufactured and tested to measure the RF properties of the cavity and couplers. In addition single cell niobium prototypes have been manufactured and tested in a vertical cryostat. The International Collider (ILC) [1] collides bunches of electrons and positrons at a crossing angle of 14 mrad. The angle between these bunches causes a loss in luminosity due to geometric effects [2]. The luminosity lost from this geometric effect can be recovered by rotating the bunches into alignment prior to collision. One possible method of rotating the bunches is to use a crab cavity [3]. A crab cavity is a transverse defecting cavity, where the phase of the cavity is such that the head and tail of the bunch receive equal and opposite kicks. As the bunches are only 500 nm wide in the horizontal plane, the cavity phase must be strictly controlled to avoid the bunch centre being deflected too much. In order to keep the phase stability within the required limits it is required that the cavity be superconducting to avoid thermal effects in both the cavity and its RF source. At the location of the crab cavity in the ILC there is only 23 cm separation between the centre of the cavity and the extraction line, hence the cavity must be small enough to fit in this space. This, along with the difficulty of making high frequency SRF components, set the frequency of the cavity to 3.9 GHz.

  2. Superconducting niobium resonator fabrication at Nuclear Science Centre

    International Nuclear Information System (INIS)

    Prakash, P.N.; Sonti, S.S.K.; Zacharias, J.; Mistri, K.K.

    2005-01-01

    This paper presents the status of the indigenous fabrication of superconducting niobium cavities for the heavy ion linac at Nuclear Science Centre. In the first phase of the fabrication a quarter wave resonator was successfully electron beam welded and tested. In the second phase two completely indigenous resonators along with the niobium slow tuner bellows have been fabricated. In addition, several critical repairs have been performed. Plans for producing resonators for the second and third linac modules have started. (author)

  3. Photonic crystal defect mode cavity modelling: a phenomenological dimensional reduction approach

    Science.gov (United States)

    Zhou, Weidong; Qiang, Zexuan; Chen, Li

    2007-05-01

    A phenomenological dimensional reduction approach (PDRA) for the cavity characteristics in defect mode based photonic crystal (PC) lasers is presented. Based on the fully vectorial three-dimensional finite-difference time-domain (3D FDTD) technique, simultaneous enhancement and suppression in spontaneous emission and absorption were obtained in an absorptive photonic crystal slab (PCS) cavity. Effective index perturbation (EIP) was proposed for fast and accurate determination of the effective index and the dominant resonant cavity frequency in a 3D PCS structure, with two-dimensional (2D) FDTD simulation. Further dimensional reduction from 2D to one-dimensional planar cavity enables phenomenological modelling of lasing characteristics via the effective reflectivity calculation and rate equation analysis. Very fast and accurate results have been achieved with this PDRA approach. A high spontaneous emission factor and cavity quality factor Q were obtained in a single defect cavity, which led to over an order reduction in lasing gain threshold. The model offers a fast and accurate tool for the design and modelling of PC defect mode cavity based devices and aids the research in the proposed novel defect mode based devices such as ultra-compact light sources on Si and spectrally resolved PC infrared photodetectors.

  4. Design and test of the microwave cavity in an optically-pumped Rubidium beam frequency standard

    Science.gov (United States)

    Liu, Chang; Wang, Yan-Hui

    2015-01-01

    We are developing a compact rubidium atomic beam frequency standard with optical pumping and detection. The cavity for microwave interrogation is an important part of the clock. The cavity in our design is a Ramsey-type, E-bend one, which is the same as the conventional method in most cesium beam clocks. Requirements for the design are proposed based on the frequency shift associated with the cavity. The basic structure of the cavity is given by theoretical analysis and detailed dimensions are determined by means of electromagnetic field simulation with the help of commercial software. The cavity is manufactured and fabricated successfully. The preliminary test result of the cavity is given, which is in good agreement with the simulation. The resonant frequency is 6.835 GHz, equal to the clock transition frequency of 87Rb, and the loaded quality factor is 500. These values are adjustable with posts outside the cavity. Estimations on the Ramsey line width and several frequency shifts are made. Project supported by the National Natural Science Foundation of China (Grant No. 11174015).

  5. High current electron beam acceleration in dielectric-filled RF cavities

    International Nuclear Information System (INIS)

    Faehl, R.J.; Keinigs, R.K.

    1996-01-01

    The acceleration of charged particles in radio frequency (RF) cavities is a widely used mode in high energy accelerators. Advantages include very high accelerating gradients and very stable phase control. A traditional limitation for such acceleration has been their use for intense, high current beam generation. This constraint arises from the inability to store a large amount of electromagnetic energy in the cavity and from loading effects of the beam on the cavity. The authors have studied a simple modification to transcend these limitations. Following Humphries and Huang, they have conducted analytic and numerical investigations of RF accelerator cavities in which a high dielectric constant material, such as water, replaces most of the cavity volume. This raises the stored energy in a cavity of given dimensions by a factor var-epsilon/var-epsilon 0 . For a water fill, var-epsilon/var-epsilon 0 ∼ 80, depending on the frequency. This introduction of high dielectric constant material into the cavity reduces the resonant frequencies by a factor of (var-epsilon/var-epsilon 0 ) 1/2 . This reduced operating frequency mans that existing high efficiency power supplies, at lower frequencies, can be used for an accelerator

  6. Transfer behavior of quantum states between atoms in photonic crystal coupled cavities

    International Nuclear Information System (INIS)

    Zhang Ke; Li Zhiyuan

    2010-01-01

    In this article, we discuss the one-excitation dynamics of a quantum system consisting of two two-level atoms each interacting with one of two coupled single-mode cavities via spontaneous emission. When the atoms and cavities are tuned into resonance, a wide variety of time-evolution behaviors can be realized by modulating the atom-cavity coupling strength g and the cavity-cavity hopping strength λ. The dynamics is solved rigorously via the eigenproblem of an ordinary coupled linear system and simple analytical solutions are derived at several extreme situations of g and λ. In the large hopping limit where g >λ, the time-evolution behavior of the system is characterized by the usual slowly varying carrier envelope superimposed upon a fast and violent oscillation. At a certain instant, the energy is fully transferred from the one quantum subsystem to the other. When the two interaction strengths are comparable in magnitude, the dynamics acts as a continuous pulse having irregular frequency and line shape of peaks and valleys, and the complicated time-evolution behaviors are ascribed to the violent competition between all the one-excitation quantum states. The coupled quantum system of atoms and cavities makes a good model to study cavity quantum electrodynamics with great freedoms of many-body interaction.

  7. Calcium fluoride whispering gallery mode optical resonator with reduced thermal sensitivity

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey

    2018-03-01

    We demonstrate a crystalline CaF2 resonator with thermal sensitivity of the optical modes approaching zero. The resonator is made by laminating a calcium fluoride layer forming an optical monolithic cavity with ceramic compensation layers. The ceramics is characterized with negative thermal expansion coefficient achievable in a certain temperature range. The thermally compensated resonator has a potential application for laser frequency stabilization.

  8. Investigation of superconducting niobium 1170 MHz cavities

    International Nuclear Information System (INIS)

    Anashin, V.V.; Bibko, S.I.; Fadeyev, E.I.

    1988-01-01

    The design, fabrication and experiments with superconducting L-band single cell cavities are described. These cavities model a cell of an accelerating RF structure. The cavities have been fabricated from technical grade and higher purity grade sheet niobium using deep-drawing, electron beam welding and chemical polishing. They have spherical geometry and are excited in the TM 010 mode. A computerized set-up was used for cavity tests. Qo=1.5 x 10 9 and E acc = 4.3 MV/m were obtained in the cavity made of higher purity grade niobium. 6 references, 8 figures, 3 tables

  9. Effect on cavity optomechanics of the interaction between a cavity field and a one-dimensional interacting bosonic gas

    International Nuclear Information System (INIS)

    Sun Qing; Hu Xinghua; Liu, W. M.; Xie, X. C.; Ji Anchun

    2011-01-01

    We investigate optomechanical coupling between one-dimensional interacting bosons and the electromagnetic field in a high-finesse optical cavity. We show that by tuning interatomic interactions, one can realize effective optomechanics with mechanical resonators ranging from side-mode excitations of a Bose-Einstein condensate (BEC) to particle-hole excitations of a Tonks-Girardeau (TG) gas. We propose that this unique feature can be formulated to detect the BEC-TG gas crossover and measure the sine-Gordon transition continuously and nondestructively.

  10. Novel Geometries for the LHC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    B. Hall, G. Burt, C. Lingwood, R. Rimmer, H. Wang

    2010-05-23

    The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the IP necessitates a more compact design than is possible with elliptical cavities such as those used at KEK. The reduction in size must be achieved without an increase in the operational frequency to maintain compatibility with the long bunch length of the LHC. This paper proposes a suitable superconducting variant of a four rod coaxial deflecting cavity (to be phased as a crab cavity), and presents analytical models and simulations of suitable designs.

  11. Novel Geometries for the LHC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    B. Hall,G. Burt,C. Lingwood,Robert Rimmer,Haipeng Wang; Hall, B. [CI Lancaster University (Great Britain); Burt, G. [CI Lancaster University (Great Britain); Lingwood, C. [CI Lancaster University (Great Britain); Rimmer, Robert [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Wang, Haipeng [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2010-05-01

    The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the IP necessitates a more compact design than is possible with elliptical cavities such as those used at KEK. The reduction in size must be achieved without an increase in the operational frequency to maintain compatibility with the long bunch length of the LHC. This paper proposes a suitable superconducting variant of a four rod coaxial deflecting cavity (to be phased as a crab cavity), and presents analytical models and simulations of suitable designs.

  12. Resonant and Ground Experimental Study on the Microwave Plasma Thruster

    Science.gov (United States)

    Yang, Juan; He, Hongqing; Mao, Genwang; Qu, Kun; Tang, Jinlan; Han, Xianwei

    2002-01-01

    chemistry. Therefore, the application of EP for the attitude control and station keeping of satellite, the propulsion of deep space exploration craft allows to reduce substantially the mass of on-board propellant and the launching cost. The EP research is now receiving high interest everywhere. microwave generating subsystem, the propellant supplying subsystem and the resonator (the thruster). Its principle is that the magnetron of the microwave generating subsystem transfers electric energy into microwave energy at given frequency which is introduced into a resonant cavity. Microwave will resonate within the cavity when it is adjusted. When the propellant gas (N2, Ar, He, NH3 or H2) is put into the cavity and coupled with microwave energy at the maximal electric intensity place, it will be broken down to form free-floating plasma, which flows from nozzle with high speed to produce thrust. Its characteristic is high efficiency, simple power supply and without electrode ablation, its specific impulse is greater than arcjet. 2450MHz, have been developed. The microwave generating subsystem and resonator of lower power MPT, 70-200W, are coaxial. The resonator with TEM resonating mode is section of coaxial wave-guide, of which one end is shorted, another is semi-opened. The maximal electric intensity field is in the lumped capacity formed between the end surface of inner conductor, retracting in the cavity, and the semi-opened surface of outer conductor. It provides favorable condition for gas breakdown. The microwave generating system and resonator of middle power MPT, 500-1,000W, are wave-guide cavity. The resonator with TM011 resonating mode is cylinder wave-guide cavity, of which two end surface are shorted. The distribution of electromagnetic field is axial symmetry, its maximal electric intensity field locates on the axis and closes to the exit of nozzle, where the propellant gas is breakdown to form free floating plasma. The plasma is free from the wall of

  13. Spectral control of elastic dynamics in metallic nano-cavities.

    Science.gov (United States)

    Ulrichs, Henning; Meyer, Dennis; Döring, Florian; Eberl, Christian; Krebs, Hans-Ulrich

    2017-09-06

    We show how the elastic response of metallic nano-cavities can be tailored by tuning the interplay with an underlying phononic superlattice. In particular, we exploit ultrafast optical excitation in order to address a resonance mode in a tungsten thin film, grown on top of a periodic MgO/ZrO 2 multilayer. Setting up a simple theoretical model, we can explain our findings by the coupling of the resonance in the tungsten to an evanescent surface mode of the superlattice. To demonstrate a second potential benefit of our findings besides characterization of elastic properties of multilayer samples, we show by micromagnetic simulation how a similar structure can be utilized for magneto-elastic excitation of exchange-dominated spin waves.

  14. Photothermal resonance

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a method for detecting photo-thermal absorbance of a material utilising a mechanically temperature sensitive resonator (20) and a sample being arrange in thermal communication with the temperature sensitive resonator. The present invention further relates...

  15. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

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

  16. Characterization of Nb coating in HIE-ISOLDE QWR superconducting accelerating cavities by means of SEM-FIB and TEM

    CERN Document Server

    Bartova, Barbora; Taborelli, M; Aebersold, A B; Alexander, D T L; Cantoni, M; Calatroni, Sergio; CERN. Geneva. ATS Department

    2015-01-01

    The Quarter Wave Resonators (QWR) high-β cavities (0.3 m diameter and 0.9 m height) are made from OFE 3D-forged copper and are coated by DC-bias diode sputtering with a thin superconducting layer of niobium. The Nb film thickness, morphology, purity and quality are critical parameters for RF performances of the cavity. They have been investigated in a detailed material study.

  17. Stimulated Raman Scattering Imposes Fundamental Limits to the Duration and Bandwidth of Temporal Cavity Solitons

    Science.gov (United States)

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

    2018-02-01

    Temporal cavity solitons (CS) are optical pulses that can persist in passive resonators, and they play a key role in the generation of coherent microresonator frequency combs. In resonators made of amorphous materials, such as fused silica, they can exhibit a spectral redshift due to stimulated Raman scattering. Here we show that this Raman-induced self-frequency-shift imposes a fundamental limit on the duration and bandwidth of temporal CSs. Specifically, we theoretically predict that stimulated Raman scattering introduces a previously unidentified Hopf bifurcation that leads to destabilization of CSs at large pump-cavity detunings, limiting the range of detunings over which they can exist. We have confirmed our theoretical predictions by performing extensive experiments in synchronously driven fiber ring resonators, obtaining results in excellent agreement with numerical simulations. Our results could have significant implications for the future design of Kerr frequency comb systems based on amorphous microresonators.

  18. Cavity enhanced eigenmode multiplexing for volume holographic data storage

    Science.gov (United States)

    Miller, Bo E.; Takashima, Yuzuru

    2017-08-01

    Previously, we proposed and experimentally demonstrated enhanced recording speeds by using a resonant optical cavity to semi-passively increase the reference beam power while recording image bearing holograms. In addition to enhancing the reference beam power the cavity supports the orthogonal reference beam families of its eigenmodes, which can be used as a degree of freedom to multiplex data pages and increase storage densities for volume Holographic Data Storage Systems (HDSS). While keeping the increased recording speed of a cavity enhanced reference arm, image bearing holograms are multiplexed by orthogonal phase code multiplexing via Hermite-Gaussian eigenmodes in a Fe:LiNbO3 medium with a 532 nm laser at two Bragg angles for expedited recording of four multiplexed holograms. We experimentally confirmed write rates are enhanced by an average factor of 1.1, and page crosstalk is about 2.5%. This hybrid multiplexing opens up a pathway to increase storage density while minimizing modifications to current angular multiplexing HDSS.

  19. Cavity cooling of free silicon nanoparticles in high vacuum.

    Science.gov (United States)

    Asenbaum, Peter; Kuhn, Stefan; Nimmrichter, Stefan; Sezer, Ugur; Arndt, Markus

    2013-01-01

    Laser cooling has given a boost to atomic physics throughout the last 30 years, as it allows one to prepare atoms in motional states, which can only be described by quantum mechanics. Most methods rely, however, on a near-resonant and cyclic coupling between laser light and well-defined internal states, which has remained a challenge for mesoscopic particles. An external cavity may compensate for the lack of internal cycling transitions in dielectric objects and it may provide assistance in the cooling of their centre-of-mass state. Here we demonstrate cavity cooling of the transverse kinetic energy of silicon nanoparticles freely propagating in high vacuum (<10(-8) mbar). We create and launch them with longitudinal velocities down to v≤1 m s(-1) using laser-induced ablation of a pristine silicon wafer. Their interaction with the light of a high-finesse infrared cavity reduces their transverse kinetic energy by up to a factor of 30.

  20. Beam position monitor using a reentrant coaxial cavity

    International Nuclear Information System (INIS)

    Bossart, R.

    1991-01-01

    A special beam position monitor is used in the enlarged straight sections of the SPS accelerator at CERN, in order to measure the position of the proton beam bunched at 200 MHz. A reentrant coaxial cavity connected to the circular vacuum chamber acts as shunt impedance for measuring the wall currents induced by the beam on the vacuum chamber. The coaxial cavity works at 200 MHz much below it's resonance frequency. Both the horizontal and vertical beam position can be measured by four orthogonal signal ports. A good response of the beam position monitor has been obtained as for signal power, precision of centre position, linearity of the position measurement and decoupling between horizontal and vertical position measurement. The total position error ε amounts to ε≤±0.6 mm±0.01 x, where x is the distance of the beam centre from the monitor centre, measured along the x-axis, for horizontal and vertical beam positions up to 60 mm. This paper describes the analysis of the reentrant coaxial cavity and it's application as a position monitor at very high frequencies. (author)

  1. Summary of the production of the ACN cavities

    CERN Document Server

    Losito, R

    2004-01-01

    The LHC-ACN RF system consists of eight normal conducting cavities (four per beam) made of bulk copper and resonating at 200.4 MHz. CERN provided the forged copper parts to the contractor for the final machining and assembly (Ettore Zanon S.p.A., based in Schio, Italy). The contractor had to weld all the flanges to the body of the cavity, machine and weld the cooling channels, carry out the final machining to have the right geometry and the requested RF surface finish, and make the final assembly of all the components by electron beam welding. The precision required during the various steps is quite tight with respect to the dimension of the cavities and would have required a very time-consuming and costly quality check during production, with the constant presence of a CERN staff member at the contractor's and subcontractor's premises. It was therefore decided, in the engineering phase, to foresee a tuning procedure before the final weldings to allow the same final result (precision on fundamental mode frequ...

  2. Understanding cavity QED effects from cavity classical electrodynamics

    International Nuclear Information System (INIS)

    Taddei, M.M.; Kort-Kamp, W.J.M.; Farina, C.

    2011-01-01

    Full text: Our work intends to show how cavity classical electrodynamics can be used for achieving results with direct quantum analogues. It is shown how the classical interaction between a real radiating electric dipole and a perfectly-conducting surface can be used to obtain information about some cavity quantum electrodynamics effects related to radiative properties of atomic systems. Based on the case of an oscillating electric dipole (a classical representation of an excited atom) in front of a perfectly-conducting sphere, two main physical quantities can be computed, the classical dipole frequency shift and the change in the rate of energy loss from radiation reaction, both due to the presence of the sphere. The link from classical to quantum can be made via interpreting, for example, the dipole frequency as the atom's dominant transition frequency. The frequency shift due to the sphere can be related through E = (h/2π) to the energy shift of the system, i.e., the dispersive interaction between the atom and the sphere; while the change in energy loss can be related to the alteration of the atom's spontaneous emission due to the sphere. The amazing result is that this classical method, once corresponded classical quantities to quantum ones such as exemplified above with frequency, can predict the two above-mentioned quantum effects analytically with the correct functional dependencies on all geometric and atomic parameters, being off only by a constant pre factor. (author)

  3. Coherence Phenomena in Coupled Optical Resonators

    Science.gov (United States)

    Smith, D. D.; Chang, H.

    2004-01-01

    We predict a variety of photonic coherence phenomena in passive and active coupled ring resonators. Specifically, the effective dispersive and absorptive steady-state response of coupled resonators is derived, and used to determine the conditions for coupled-resonator-induced transparency and absorption, lasing without gain, and cooperative cavity emission. These effects rely on coherent photon trapping, in direct analogy with coherent population trapping phenomena in atomic systems. We also demonstrate that the coupled-mode equations are formally identical to the two-level atom Schrodinger equation in the rotating-wave approximation, and use this result for the analysis of coupled-resonator photon dynamics. Notably, because these effects are predicted directly from coupled-mode theory, they are not unique to atoms, but rather are fundamental to systems of coherently coupled resonators.

  4. Anomalous ring-down effects and breakdown of the decay rate concept in optical cavities with negative group delay

    International Nuclear Information System (INIS)

    Lauprêtre, T; Goldfarb, F; Bretenaker, F; Schwartz, S; Ghosh, R; Carusotto, I

    2012-01-01

    The propagation of light pulses through negative group velocity media is known to give rise to a number of paradoxical situations that seem to violate causality. The solution of these paradoxes has triggered the investigation of a number of interesting and unexpected features of light propagation. Here, we report a combined theoretical and experimental study of the ring-down oscillations in optical cavities filled with a medium with a sufficiently negative frequency dispersion to give a negative round-trip group delay time. We theoretically anticipate that causality imposes the existence of additional resonance peaks in the cavity transmission, resulting in a non-exponential decay of the cavity field and in a breakdown of the cavity decay rate concept. Our predictions are validated by simulations and by an experiment using a room-temperature gas of metastable helium atoms in the detuned electromagnetically induced transparency regime as the cavity medium. (paper)

  5. Temperature Structure of a Coronal Cavity

    Science.gov (United States)

    Kucera, T. A.; Gibson, S. E.; Schmit, D. J.

    2011-01-01

    we analyze the temperature structure of a coronal cavity observed in Aug. 2007. coronal cavities are long, low-density structures located over filament neutral lines and are often seen as dark elliptical features at the solar limb in white light, EUV and x-rays. when these structures erupt they form the cavity portions of CMEs. It is important to establish the temperature structure of cavities in order to understand the thermodynamics of cavities in relation to their three-dimensional magnetic structure. To analyze the temperature we compare temperature ratios of a series of iron lines observed by the Hinode/EUv Imaging spectrometer (EIS). We also use those lines to constrain a forward model of the emission from the cavity and streamer. The model assumes a coronal streamer with a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel lenth. Temperature and density can be varied as a function of altitude both in the cavity and streamer. The general cavity morphology and the cavity and streamer density have already been modeled using data from STEREO's SECCHI/EUVI and Hinode/EIS (Gibson et al 2010 and Schmit & Gibson 2011).

  6. Cancer of the oral cavity.

    Science.gov (United States)

    Montero, Pablo H; Patel, Snehal G

    2015-07-01

    Cancer of the oral cavity is one of the most common malignancies worldwide. Although early diagnosis is relatively easy, presentation with advanced disease is not uncommon. The standard of care is primary surgical resection with or without postoperative adjuvant therapy. Improvements in surgical techniques combined with the routine use of postoperative radiation or chemoradiation therapy have resulted in improved survival. Successful treatment is predicated on multidisciplinary treatment strategies to maximize oncologic control and minimize impact of therapy on form and function. Prevention of oral cancer requires better education about lifestyle-related risk factors, and improved awareness and tools for early diagnosis. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    Ullah, Kamran; Jing, Hui; Saif, Farhan

    2018-03-01

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

  8. Infrared nano-sensor based on doubly splited optomechanical cavity

    Science.gov (United States)

    Zhang, Yeping; Ai, Jie; Xiang, Yanjun; Ma, Liehua; Li, Tao; Ma, Jingfang

    2017-10-01

    Optomechanical crystal (OMC) cavities are simultaneous have photonic and phononic bandgaps. The strong interaction between high co-localized optical mode and mechanical mode are excellent candidates for precision measurements due to their simplicity, sensitivity and all optical operation. Here, we investigate OMC nanobeam cavities in silicon operating at the near-infrared wavelengths to achieve high optomechanical coupling rate and ultra-small motion mass. Numerical simulation results show that the optical Q-factor reached to 1.2×105 , which possesses an optical mode resonating at the wavelength of 1181 nm and the extremely localized mechanical mode vibrating at 9.2GHz. Moreover, a novel type of doubly splited nanocavity tailored to sensitively measure torques and mass. In the nanomechanical resonator central hollow area suspended low-mass elements (<100fg) are sensitive to environmental stimulate. By changing the split width, an ultra-small effective motion mass of only 4fg with a mechanical frequency as high as 11.9GHz can be achieved, while the coupling rate up to 1.58MHz. Potential applications on these devices include sensing mass, acceleration, displacement, and magnetic probing the quantum properties of nanoscale systems.

  9. Development of a fast piezo-based frequency tuner for superconducting CH cavities

    International Nuclear Information System (INIS)

    Amberg, Michael

    2015-01-01

    In this thesis, a fast piezo-based frequency tuner for current and prospective superconducting (sc) CH-cavities has been developed. The novel tuning concept differs fundamentally from conventional tuning systems for superconducting cavities. So called dynamic bellow tuners are welded into the resonator to act against slow and fast frequency variations during operation. Because of their adjustable length it is possible to specifically influence the capacitance and therefore the resonance frequency of the cavity. To change the length of the dynamic bellow tuners the frequency tuner drive, which consists of a slow tuning device controlled by a stepper motor and a fast piezo-based tuning system, is mounted to the helium vessel of the cavity. To validate the whole tuning concept a frequency tuner drive prototype was built in the workshop of the Institute for Applied Physics (IAP) of Frankfurt University. First successful room temperature measurements show that the developed frequency tuning system is an excellent and promising candidate to fulfill the requirements of slow and fast frequency tuning of sc CH-cavities during operation. Furthermore, several coupled structural and electromagnetic simulations of the sc 325 MHz CH-cavity as well as the sc 217 MHz CH-cavity have been performed with the simulation softwares ANSYS Workbench and CST MicroWave Studio, respectively. With these simulations it was possible to reduce the required frequency range and thus the mechanical stroke of the dynamic bellow tuners on the one hand, and on the other hand the mechanical stability of the particular CH-cavity was investigated to avoid plastic deformations due to limiting external effects. To verify the accuracy of the coupled simulations the structural mechanical behaviour and the resulting frequency variations of the sc CH-cavities dependent on the external influences were measured at room temperature as well as at cryogenic temperatures around 4.2 K. The measurement results of both

  10. Third harmonic cavity design and RF measurements for the Frascati DAΦNE collider

    Directory of Open Access Journals (Sweden)

    David Alesini

    2004-09-01

    Full Text Available Third harmonic passive RF cavities have been proposed for installation in both rings of the DAΦNE factory collider to improve the Touschek lifetime and to increase the Landau damping. This paper illustrates the design of the harmonic cavities. The main requirements were to obtain a relatively low R/Q factor and a quality factor Q as high as possible to satisfy beam dynamics requirements and to damp all the higher order mode (HOM to a harmless level in order to avoid multibunch instabilities. A spherical shape of the cavity central body has been chosen as an optimum compromise between a high Q resonator and a low R/Q factor. HOM suppression has been provided by a ferrite ring damper designed for the superconducting cavities of the high energy ring of the KEK-B factory. The design and electromagnetic properties of the resonant modes have been studied with MAFIA and HFSS codes. Cavities have been made of aluminum and the RF measurements have been performed to characterize them. The measurements are in a good agreement with numerical simulations results, demonstrating a satisfactory HOM damping.

  11. Ultraviolet optomechanical crystal cavities with ultrasmall modal mass and high optomechanical coupling rate

    Science.gov (United States)

    Zhou, Wen; Yu, Zejie; Ma, Jingwen; Zhu, Bingqing; Tsang, Hon Ki; Sun, Xiankai

    2016-01-01

    Optomechanical crystal (OMC) cavities which exploit the simultaneous photonic and phononic bandgaps in periodic nanostructures have been utilized to colocalize, couple, and transduce optical and mechanical resonances for nonlinear interactions and precision measurements. The development of near-infrared OMC cavities has difficulty in maintaining a high optomechanical coupling rate when scaling to smaller mechanical modal mass because of the reduction of the spatial overlap between the optical and mechanical modes. Here, we explore OMC nanobeam cavities in gallium nitride operating at the ultraviolet wavelengths to overcome this problem. With a novel optimization strategy, we have successfully designed an OMC cavity, with a size of 3.83 × 0.17 × 0.13 μm3 and the mechanical modal mass of 22.83 fg, which possesses an optical mode resonating at the wavelength of 393.03 nm and the fundamental mechanical mode vibrating at 14.97 GHz. The radiation-limited optical Q factor, mechanical Q factor, and optomechanical coupling rate are 2.26 × 107, 1.30 × 104, and 1.26 MHz, respectively. Our design and optimization approach can also serve as the general guidelines for future development of OMC cavities with improved device performance. PMID:27892523

  12. Superconducting microwave cavity parametric converter transducer sensitive to 10-19 M harmonic motion

    International Nuclear Information System (INIS)

    Reece, C.E.

    1984-01-01

    Toward the development of a transducer suitable for the detection of high frequency gravitational effects, a superconducting microwave coupled-cavity parametric converter transducer has been analyzed, developed and tested. An analysis is presented of the intermodal parametric conversion which is produced by harmonic perturbaton of the length of a 10 GHz TE 011 mode cylindrical resonant cavity. The converter is examined as a transducer of displacement with harmonic frequency near the intermodal difference frequency. Transducer sensitivity dependence upon cavity tunings, couplings, and Q-factors is analyzed and experimentally tested with excellent agreement. The transducer consists of two identical coupled TE 011 niobium cavities with one endwall driven into mechanical oscillation by an externally mounted piezoelectric ceramic. A displacement with effective amplitude (3.7 +/- 1.3) x 10 -19 m and frequency 1.13 MHz has been observed by detecting a 10GHz conversion power of 10 -21 watts. This measurement was obtained with 0.12 mJ stored in a cavity resonance with an unloaded Q-factor of 6.7 x 10 8 at 1.55 0 K. The applications of this device in the detection of high frequency gravitational effects are also discussed. Finally, the prospects for improvement of transducer sensitivity and the ultimate limitations are presented

  13. Optimized coplanar waveguide resonators for a superconductor–atom interface

    Energy Technology Data Exchange (ETDEWEB)

    Beck, M. A., E-mail: mabeck2@wisc.edu; Isaacs, J. A.; Booth, D.; Pritchard, J. D.; Saffman, M.; McDermott, R. [Department of Physics, University Of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)

    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.

  14. Temperature control feedback loops for the linac upgrade side coupled cavities at Fermilab

    International Nuclear Information System (INIS)

    Crisp, J.

    1990-01-01

    The linac upgrade project at Fermilab will replace the last 4 drift-tube linac tanks with seven side coupled cavity strings. This will increase the beam energy from 200 to 400 MeV at injection into the Booster accelerator. The main objective of the temperature loop is to control the resonant frequency of the cavity strings. A cavity string will constant of 4 sections connected with bridge couplers driven with a 12 MW klystron at 805 MHz. Each section is a side coupled cavity chain consisting of 16 accelerating cells and 15 side coupling cells. For the linac upgrade, 7 full cavity strings will be used. A separate temperature control system is planned for each of the 28 accelerating sections, the two transition sections, and the debuncher section. The cavity strings will be tuned to resonance for full power beam loaded conditions. A separate frequency loop is planned that will sample the phase difference between a monitor placed in the end cell of each section and the rf drive. The frequency loop will control the set point for the temperature loop which will be able to maintain the resonant frequency through periods within beam or rf power. The frequency loop will need the intelligence required to determine under what conditions the phase error information is valid and the temperature set point should be adjusted. This paper will discuss some of the reason for temperature control, the implementation, and some of the problems encountered. An appendix contains some useful constants and descriptions of some of the sensor and control elements used. 13 figs

  15. Rebuild of Capture Cavity 1 at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Harms, E. [Fermilab; Arkan, T. [Fermilab; Borissov, E. [Fermilab; Dhanaraj, N. [Fermilab; Hocker, A. [Fermilab; Orlov, Y. [Fermilab; Peterson, T. [Fermilab; Premo, K. [Fermilab

    2014-01-01

    The front end of the proposed Advanced Superconducting Test Accelerator at Fermilab employs two single cavity cryomodules, known as 'Capture Cavity 1' and 'Capture Cavity 2', for the first stage of acceleration. Capture Cavity 1 was previously used as the accelerating structure for the A0 Photoinjector to a peak energy of ~14 MeV. In its new location a gradient of ~25 MV/m is required. This has necessitated a major rebuild of the cryomodule including replacement of the cavity with a higher gradient one. Retrofitting the cavity and making upgrades to the module required significant redesign. The design choices and their rationale, summary of the rebuild, and early test results are presented.

  16. Cantilever piezoelectric energy harvester with multiple cavities

    International Nuclear Information System (INIS)

    S Srinivasulu Raju; M Umapathy; G Uma

    2015-01-01

    Energy harvesting employing piezoelectric materials in mechanical structures such as cantilever beams, plates, diaphragms, etc, has been an emerging area of research in recent years. The research in this area is also focused on structural tailoring to improve the harvested power from the energy harvesters. Towards this aim, this paper presents a method for improving the harvested power from a cantilever piezoelectric energy harvester by introducing multiple rectangular cavities. A generalized model for a piezoelectric energy harvester with multiple rectangular cavities at a single section and two sections is developed. A method is suggested to optimize the thickness of the cavities and the number of cavities required to generate a higher output voltage for a given cantilever beam structure. The performance of the optimized energy harvesters is evaluated analytically and through experimentation. The simulation and experimental results show that the performance of the energy harvester can be increased with multiple cavities compared to the harvester with a single cavity. (paper)

  17. Unique space saving accelerator cavity design

    International Nuclear Information System (INIS)

    Kim, H.; Fugitt, J.; Crosby, F.; Johnson, R.

    1981-03-01

    A cavity with 3 series gaps was designed and modeled to operate at 70 MHz as a SuperHILAC post acceleration buncher (8.5 MeV/A). Because of a cross-coupling scheme, the 3 cells operate in the 1/2 β lambda mode instead of the β lambda mode of an Alvarez cavity. This coupling results in a cavity with diameter reduced from 3 to less than one meter and a length half that of an Alvarez cavity for the same energy gain. The 3 gaps are electrically in parallel but mechanically in series. The cavity has high Q and shunt impedance. This type of cavity appears to be useful for low velocity beams with β less than or equal to 0.2

  18. Schumann resonance for tyros essentials of global electromagnetic resonance in the Earth-ionosphere cavity

    CERN Document Server

    Nickolaenko, Alexander

    2014-01-01

    This thorough book describes data gathering equipment and field-sites, industrial and natural interference, typical results and common obstacles to measurement. Covers representative results, unusual radio signals in extremely low frequency bands and more.

  19. Deterministic quantum state transfer between remote qubits in cavities

    Science.gov (United States)

    Vogell, B.; Vermersch, B.; Northup, T. E.; Lanyon, B. P.; Muschik, C. A.

    2017-12-01

    Performing a faithful transfer of an unknown quantum state is a key challenge for enabling quantum networks. The realization of networks with a small number of quantum links is now actively pursued, which calls for an assessment of different state transfer methods to guide future design decisions. Here, we theoretically investigate quantum state transfer between two distant qubits, each in a cavity, connected by a waveguide, e.g., an optical fiber. We evaluate the achievable success probabilities of state transfer for two different protocols: standard wave packet shaping and adiabatic passage. The main loss sources are transmission losses in the waveguide and absorption losses in the cavities. While special cases studied in the literature indicate that adiabatic passages may be beneficial in this context, it remained an open question under which conditions this is the case and whether their use will be advantageous in practice. We answer these questions by providing a full analysis, showing that state transfer by adiabatic passage—in contrast to wave packet shaping—can mitigate the effects of undesired cavity losses, far beyond the regime of coupling to a single waveguide mode and the regime of lossless waveguides, as was proposed so far. Furthermore, we show that the photon arrival probability is in fact bounded in a trade-off between losses due to non-adiabaticity and due to coupling to off-resonant waveguide modes. We clarify that neither protocol can avoid transmission losses and discuss how the cavity parameters should be chosen to achieve an optimal state transfer.

  20. Low loss optomechanical cavities based on silicon oscillator

    Science.gov (United States)

    Borrielli, A.; Pontin, A.; Cataliotti, F. S.; Marconi, L.; Marin, F.; Marino, F.; Pandraud, G.; Prodi, G. A.; Serra, E.; Bonaldi, M.

    2015-05-01

    In an optomechanical cavity the optical and mechanical degree of freedom are strongly coupled by the radiation pressure of the light. This field of research has been gathering a lot of momentum during the last couple of years, driven by the technological advances in microfabrication and the first observation of quantum phenomena. These results open new perspectives in a wide range of applications, including high sensitivity measurements of position, acceleration, force, mass, and for fundamental research. We are working on low frequency pondero-motive light squeezing as a tool for improving the sensitivity of audio frequency measuring devices such as magnetic resonance force microscopes and gravitational-wave detectors. It is well known that experiments aiming to produce and manipulate non-classical (squeezed) light by effect of optomechanical interaction need a mechanical oscillator with low optical and mechanical losses. These technological requirements permit to maximize the force per incoming photon exerted by the cavity field on the mechanical element and to improve the element's response to the radiation pressure force and, at the same time, to decrease the influence of the thermal bath. In this contribution we describe a class of mechanical devices for which we measured a mechanical quality factor up to 1.2 × 106 and with which it was possible to build a Fabry-Perot cavity with optical finesse up to 9 × 104. From our estimations, these characteristics meet the requirements for the generation of radiation squeezing and quantum correlations in the ˜ 100kHz region. Moreover our devices are characterized by high reproducibility to allow inclusion in integrated systems. We show the results of the characterization realized with a Michelson interferometer down to 4.2K and measurements in optical cavities performed at cryogenic temperature with input optical powers up to a few mW. We also report on the dynamical stability and the thermal response of the system.

  1. Engineering-reflected phase in Fabry-Perot sensors with resonant mirrors.

    Science.gov (United States)

    Gellineau, Antonio; Wong, Yu-Po; Solgaard, Olav

    2013-12-01

    Fabry-Perot cavities made with photonic crystal (PC) mirrors and other resonant structures exhibit nontraditional characteristics due to the strong wavelength dependence of their reflected phase. This Letter describes how engineering the phase of PC mirrors enables sensors that are tolerant to variations in laser center frequency and line width. Reflection spectra measurements of Fabry-Perot cavities made with PC mirrors were collected as a function of wavelength and cavity length, providing experimental verification of theory and simulations.

  2. Design of 325 MHz spoke cavity

    International Nuclear Information System (INIS)

    Sha Peng; Huang Hong; Dai Jianping; Zu Guoquan; Li Han

    2012-01-01

    Spoke cavity can be used in the low-energy section of the proton accelerator. It has many significant advantages: compact structure, high value of R/Q, etc. The ADS (Accelerator Driven System) project will adopt many spoke cavities with different β values. Therefore, IHEP has began the research of β=0.14, 325 MHz spoke cavity. In this pa per, the dimensions, RF performances and mechanical properties of it are studied. (authors)

  3. Induced Cavities for Photonic Quantum Gates

    Science.gov (United States)

    Lahad, Ohr; Firstenberg, Ofer

    2017-09-01

    Effective cavities can be optically induced in atomic media and employed to strengthen optical nonlinearities. Here we study the integration of induced cavities with a photonic quantum gate based on Rydberg blockade. Accounting for loss in the atomic medium, we calculate the corresponding finesse and gate infidelity. Our analysis shows that the conventional limits imposed by the blockade optical depth are mitigated by the induced cavity in long media, thus establishing the total optical depth of the medium as a complementary resource.

  4. Dynamic mode decomposition of turbulent cavity flows for self-sustained oscillations

    International Nuclear Information System (INIS)

    Seena, Abu; Sung, Hyung Jin

    2011-01-01

    Highlights: ► DMD modes were extracted from two cavity flow data set at Re D = 12,000 and 3000. ► At Re D = 3000, frequencies of boundary layer and shear layer structures coincides. ► Boundary layer structures exceed in size with shear layer structures. ► At Re D = 12,000, structure showed coherence leading to self-sustained oscillations. ► Hydrodynamic resonance occurs if coherence exists in wavenumber and frequency. - Abstract: Self-sustained oscillations in a cavity arise due to the unsteady separation of boundary layers at the leading edge. The dynamic mode decomposition method was employed to analyze the self-sustained oscillations. Two cavity flow data sets, with or without self-sustained oscillations and possessing thin or thick incoming boundary layers (Re D = 12,000 and 3000), were analyzed. The ratios between the cavity depth and the momentum thickness (D/θ) were 40 and 4.5, respectively, and the cavity aspect ratio was L/D = 2. The dynamic modes extracted from the thick boundary layer indicated that the upcoming boundary layer structures and the shear layer structures along the cavity lip line coexisted with coincident frequency space but with different wavenumber space, whereas structures with a thin boundary layer showed complete coherence among the modes to produce self-sustained oscillations. This result suggests that the hydrodynamic resonances that gave rise to the self-sustained oscillations occurred if the upcoming boundary layer structures and the shear layer structures coincided, not only in frequencies, but also in wavenumbers. The influences of the cavity dimensions and incoming momentum thickness on the self-sustained oscillations were examined.

  5. Thermodynamics and dynamics of atomic self-organization in an optical cavity

    Science.gov (United States)

    Schütz, Stefan; Jäger, Simon B.; Morigi, Giovanna

    2015-12-01

    Pattern formation of atoms in high-finesse optical resonators results from the mechanical forces of light associated with superradiant scattering into the cavity mode. It occurs when the laser intensity exceeds a threshold value such that the pumping processes counteract the losses. We consider atoms driven by a laser and coupling with a mode of a standing-wave cavity and describe their dynamics with a Fokker-Planck equation, in which the atomic motion is semiclassical but the cavity field is a full quantum variable. The asymptotic state of the atoms is a thermal state, whose temperature is solely controlled by the detuning between the laser and the cavity frequency and by the cavity loss rate. From this result we derive the free energy and show that in the thermodynamic limit self-organization is a second-order phase transition. The order parameter is the field inside the resonator to which one can associate a magnetization in analogy to ferromagnetism, the control field is the laser intensity, but the steady state is intrinsically out of equilibrium. In the symmetry-broken phase, quantum noise induces jumps of the spatial density between two ordered patterns: We characterize the statistical properties of this temporal behavior at steady state and show that the thermodynamic properties of the system can be extracted by detecting the light at the cavity output. The results of our analysis are in full agreement with previous studies; we extend them by deriving a self-consistent theory which is valid also when the cavity field is in the shot-noise limit and elucidate the nature of the self-organization transition.

  6. The fast piezo-based frequency tuner for sc CH-cavities

    Energy Technology Data Exchange (ETDEWEB)

    Amberg, Michael [Helmholtz-Institut Mainz (HIM), Mainz (Germany); IAP University of Frankfurt, Frankfurt am Main (Germany); Aulenbacher, Kurt; Barth, Winfried [Helmholtz-Institut Mainz (HIM), Mainz (Germany); Busch, Marco; Dziuba, Florian; Podlech, Holger; Ratzinger, Ulrich [IAP University of Frankfurt, Frankfurt am Main (Germany)

    2014-07-01

    Superconducting (sc) structures have to fulfill strict mechanical requirements to assure a stable operation of a cavity. Even small mechanical disturbances caused by effects like microphonic noise, pressure fluctuations of the liquid helium bath or Lorentz force detuning can change the resonance frequency of the cavity in the range of several hundred kHz. To control the slow and fast frequency variations during operation a compact frequency tuner prototype equipped with a stepper motor and a piezo actuator has been developed at the Institute for Applied Physics (IAP) of Frankfurt University. The tuner design and the results of first mechanical tests at room temperature of the first prototype are presented.

  7. Computation of the frequency response of a nonlinearly loaded antenna within a cavity

    Directory of Open Access Journals (Sweden)

    F. Gronwald

    2004-01-01

    Full Text Available We analyze a nonlinearly loaded dipole antenna which is located within a rectangular cavity and excited by an electromagnetic signal. The signal is composed from two different frequencies. In order to calculate the spectrum of the resulting electromagnetic field within the resonator we transform the antenna problem into a network problem. This requires to precisely determine the antenna impedance within the cavity. The resulting nonlinear equivalent network is solved by means of the harmonic balance technique. As a result the occurrence of low intermodulation frequencies within the spectrum is verified.

  8. Chip-integrated plasmonic cavity-enhanced single nitrogen-vacancy center emission

    DEFF Research Database (Denmark)

    Siampour, Hamidreza; Kumar, Shailesh; Bozhevolnyi, Sergey I.

    2017-01-01

    High temporal stability and spin dynamics of individual nitrogen-vacancy (NV) centers in diamond crystals make them one of the most promising quantum emitters operating at room temperature. We demonstrate a chip-integrated cavity-coupled emission into propagating surface plasmon polariton (SPP......-beam lithography of hydrogen silsesquioxane resist deposited on silver-coated silicon substrates. A quality factor of ∼70 for the cavity (full width at half maximum ∼10 nm) with full tunability of the resonance wavelength is demonstrated. An up to 42-fold decay rate enhancement of the spontaneous emission...

  9. Novel Geometries for the LHC CRAB Cavity

    CERN Document Server

    Hall, Ben

    2010-01-01

    In 2017 the LHC is envisioned to increase its luminosity via an upgrade. This upgrade is likely to require a large crossing angle hence a crab cavity is required to align the bunches prior to collision. There are two possible schemes for crab cavity implementation, global and local. In a global crab cavity the crab cavity is far from the IP and the bunch rotates back and forward as it traverses around the accelerator in a closed orbit. For this scheme a two-cell elliptical squashed cavity at 800 MHz is preferred. To avoid any potential beam instabilities all the parasitic modes of the cavities must be damped strongly, however crab cavities have lower order and same order modes in addition to the usual higher order modes and hence a novel damping scheme must be used to provide sufficient damping of these modes. In the local scheme two crab cavities are placed at each side of the IP two start and stop rotation of the bunches. This would require crab cavities much smaller transversely than in the global scheme b...

  10. Superconducting niobium cavity with cooling fins

    International Nuclear Information System (INIS)

    Isagawa, Shigeru.

    1978-04-01

    Cooling efficiency of a superconducting cavity is shown to be improved by applying a fin structure. Internal heating can be suppressed in a certain degree and the higher rf field is expected to be reached on surfaces of the cavity which is immersed in superfluid He 4 liquid. The rf measurements were made on a C-band niobium cavity with cylindrical and circular fins around the wall. Fields of 39 mT and 25 MV/m were attained for TM 010 mode cavity after surface treatments including high temperature annealing in a UHV furnace. (auth.)

  11. Design of the ILC Crab Cavity System

    Energy Technology Data Exchange (ETDEWEB)

    Adolphsen, C.; Beard, C.; Bellantoni, L.; Burt, G.; Carter, R.; Chase, B.; Church, M.; Dexter, A.; Dykes, M.; Edwards, H.; Goudket, P; Jenkins, R.; Jones, R.M.; Kalinin,; Khabiboulline, T.; Ko, K.; Latina, A.; Li, Z.; Ma, L.; McIntosh, P.; Ng, C.; /SLAC /Daresbury /Fermilab /Cockcroft Inst. Accel. Sci. Tech. /CERN

    2007-08-15

    The International Linear Collider (ILC) has a 14 mrad crossing angle in order to aid extraction of spent bunches. As a result of the bunch shape at the interaction point, this crossing angle at the collision causes a large luminosity loss which can be recovered by rotating the bunches prior to collision using a crab cavity. The ILC baseline crab cavity is a 9-cell superconducting dipole cavity operating at a frequency of 3.9 GHz. In this paper the design of the ILC crab cavity and its phase control system, as selected for the RDR in February 2007 is described in fuller detail.

  12. Modeling of mode-locked coupled-resonator optical waveguide lasers

    DEFF Research Database (Denmark)

    Agger, Christian; Skovgård, Troels Suhr; Gregersen, Niels

    2010-01-01

    Coupled-resonator optical waveguides made from coupled high-Q photonic crystal nanocavities are investigated for use as cavities in mode-locked lasers. Such devices show great potential in slowing down light and can serve to reduce the cavity length of a mode-locked laser. An explicit expression...

  13. Compensating microphonics in SRF cavities to ensure beam stability for future free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Axel

    2008-07-21

    In seeded High-Gain-Harmonic-Generation free electron lasers or energy recovery linear accelerators the requirements for the bunch-to-bunch timing and energy jitter of the beam are in the femtosecond and per mill regime. This implies the ability to control the cavity radiofrequency (RF) field to an accuracy of 0.02 in phase and up to 1.10{sup -4} in amplitude. For the planned BESSY-FEL it is envisaged to operate 144 superconducting 1.3 GHz cavities of the 2.3 GeV driver linac in continuous wave mode and at a low beam current. The cavity resonance comprises a very narrow bandwidth of the order of tens of Hertz. Such cavities have been characterized under accelerator like conditions in the HoBiCaT test facility. It was possible to measure the error sources affecting the field stability in continuous wave (CW) operation. Microphonics, the main error source for a mechanical detuning of the cavities, lead to an average fluctuation of the cavity resonance of 1-5 Hz rms. Furthermore, the static and dynamic Lorentz force detuning and the helium pressure dependance of the cavity resonance have been measured. Single cavity RF control and linac bunch-to-bunch longitudinal phase space modeling containing the measured properties showed, that it is advisable to find means to minimize the microphonics detuning by mechanical tuning. Thus, several fast tuning systems have been tested for CW operation. These tuners consist of a motor driven lever for slow and coarse tuning and a piezo that is integrated into the tuner support for fast and fine tuning. Regarding the analysis of the detuning spectrum an adaptive feedforward method based on the least-mean-square filter algorithm has been developed for fast cavity tuning. A detuning compensation between a factor of two and up to a factor of seven has been achieved. Modeling the complete system including the fast tuning scheme, showed that the requirements of the BESSY-FEL are attainable. (orig.)

  14. Large and well-defined Rabi splitting in a semiconductor nanogap cavity.

    Science.gov (United States)

    Uemoto, Mitsuharu; Ajiki, Hiroshi

    2014-09-22

    We propose a nanogap structure composed of semiconductor nanoparticles forming an optical cavity. The resonant excitation of excitons in the nanoparticles can generate a localized strong light field in the gap region, also called "hot spot". The spectral width of the hot spot is significantly narrow because of the small exciton damping and the dephasing at low temperature, so the semiconductor nanogap structure acts as a high-Q cavity. In addition, the interaction between light and matter at the nanogap is significantly larger than that in a conventional microcavity, because the former has a small cavity-mode volume beyond the diffraction limit. We theoretically demonstrate the large and well-defined vacuum-Rabi splitting of a two-level emitter placed inside the semiconductor nanogap cavity: the Rabi splitting energy of 1.7 meV for the transition dipole moment of the emitter (25 Debye) is about 6.3 times larger than the spectral width. An optical cavity providing such a large and well-defined Rabi splitting is highly suited for studying characteristic features of the cavity quantum electrodynamics and for the development of new applications.

  15. Design of a multi beam klystron cavity from its single beam parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kant, Deepender, E-mail: dkc@ceeri.ernet.in; Joshi, L. M. [CSIR-Central Electronics Engineering Research Institute, Pilani (India); Janyani, Vijay [Department of ECE, MNIT, Jaipur (India)

    2016-03-09

    The klystron is a well-known microwave amplifier which uses kinetic energy of an electron beam for amplification of the RF signal. There are some limitations of conventional single beam klystron such as high operating voltage, low efficiency and bulky size at higher power levels, which are very effectively handled in Multi Beam Klystron (MBK) that uses multiple low purveyance electron beams for RF interaction. Each beam propagates along its individual transit path through a resonant cavity structure. Multi-Beam klystron cavity design is a critical task due to asymmetric cavity structure and can be simulated by 3D code only. The present paper shall discuss the design of multi beam RF cavities for klystrons operating at 2856 MHz (S-band) and 5 GHz (C-band) respectively. The design approach uses some scaling laws for finding the electron beam parameters of the multi beam device from their single beam counter parts. The scaled beam parameters are then used for finding the design parameters of the multi beam cavities. Design of the desired multi beam cavity can be optimized through iterative simulations in CST Microwave Studio.

  16. Microwave induced plasma discharge in multi-cell superconducting radio-frequency cavity

    International Nuclear Information System (INIS)

    Ahmed, Shahid; Mammosser, John D.

    2015-01-01

    A R&D effort for in situ cleaning of 1.5 GHz Superconducting Radio Frequency (SRF) cavities at room temperature using the plasma processing technique has been initiated at Jefferson Lab. This is a step toward the cleaning of cryomodules installed in the Continuous Electron Beam Accelerator Facility (CEBAF). For this purpose, we have developed an understanding of plasma discharge in a 5-cell CEBAF-type SRF cavity having configurations similar to those in the main accelerator. The focus of this study involves the detailed investigations of developing a plasma discharge inside the cavity volume and avoids the breakdown condition in the vicinity of the ceramic RF window. A plasma discharge of the gas mixture Ar–O 2 (90%:10%) can be established inside the cavity volume by the excitation of a resonant 4π/5 TM 010 -mode driven by a klystron. The absence of any external magnetic field for generating the plasma is suitable for cleaning cavities installed in a complex cryomodule assembly. The procedures developed in these experimental investigations can be applied to any complex cavity structure. Details of these experimental measurements and the observations are discussed in the paper

  17. Microwave induced plasma discharge in multi-cell superconducting radio-frequency cavity

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Shahid, E-mail: shahid.ahmed@ieee.org [BML Munjal University, Gurgaon, Haryana 123413 (India); Mammosser, John D. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-07-15

    A R&D effort for in situ cleaning of 1.5 GHz Superconducting Radio Frequency (SRF) cavities at room temperature using the plasma processing technique has been initiated at Jefferson Lab. This is a step toward the cleaning of cryomodules installed in the Continuous Electron Beam Accelerator Facility (CEBAF). For this purpose, we have developed an understanding of plasma discharge in a 5-cell CEBAF-type SRF cavity having configurations similar to those in the main accelerator. The focus of this study involves the detailed investigations of developing a plasma discharge inside the cavity volume and avoids the breakdown condition in the vicinity of the ceramic RF window. A plasma discharge of the gas mixture Ar–O{sub 2} (90%:10%) can be established inside the cavity volume by the excitation of a resonant 4π/5 TM{sub 010}-mode driven by a klystron. The absence of any external magnetic field for generating the plasma is suitable for cleaning cavities installed in a complex cryomodule assembly. The procedures developed in these experimental investigations can be applied to any complex cavity structure. Details of these experimental measurements and the observations are discussed in the paper.

  18. Cryogenic sub-system for the 56 MHz SRF storage cavity for RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y.; Than, R.; Orfin, P.; Lederle, D.; Tallerico, T.; Masi L.; Talty, P.; Zhang, Y.

    2011-03-28

    A 56 MHz Superconducting RF Storage Cavity is being constructed for the RHIC collider. This cavity is a quarter wave resonator that will be operated in a liquid helium bath at 4.4 K. The cavity requires an extremely quiet environment to maintain its operating frequency. The cavity, besides being engineered for a mechanically quiet system, also requires a quiet cryogenic system. The helium is taken from RHIC's main helium supply header at 3.5 atm, 5.3K at a phase separator tank. The boil-off is sent back to the RHIC refrigeration system to recover the cooling. To acoustically separate the RHIC helium supply and return lines, a condenser/boiler heat exchanger condenses the helium vapor generated in the RF cavity bath. A system description and operating parameters are given about the cryogen delivery system. The 56 MHz superconducting storage RF cavity project is making progress. The cryogenic system design is in its final stage. The helium supply lines have been tapped into the RHIC helium distribution lines. The plate-and-fin heat exchanger design is near completion and specification will be sent out for bid soon. The cold helium vapor heating system design will start soon as well. A booster compressor specification is underway. The first phase separator and transfer line design work is near completion and will be sent out for bid soon.

  19. Fundamental damper power calculation of the 56 MHz SRF cavity for RHIC

    International Nuclear Information System (INIS)

    Wu, Q.; Bellavia, S.; Ben-Zvi, I.; Grau, M.; Miglionico, G.; Pai, C.

    2011-01-01

    At each injection period during RHIC's operation, the beam's frequency sweeps across a wide range, and some of its harmonics will cross the frequency of the 56MHz SRF cavity. To avoid excitation of the cavity at these times, we designed a fundamental damper for the quarter-wave resonator to damp the cavity heavily. The power extracted by the fundamental damper should correspond to the power handling ability of the system at all stages. In this paper, we discuss the power output from the fundamental damper when it is fully extracted, inserted, and any intermediate point. A Fundamental Damper (FD) will greatly reduce the cavity's Q factor to ∼300 during the acceleration phase of the beam. However, when the beam is at store and the FD is removed, the cavity is excited by both the yellow and the blue beams at 2 x 0.3A to attain the required 2MV voltage across its gap. The cavity then is operated to increase the luminosity of the RHIC experiments. Table 1 lists the parameters of the FD. Figure 1 shows the configuration of the FD fully inserted into the 56MHz SRF cavity; this complete insertion is defined as the start location (0cm) of FD simulation, an assumption we make throughout this paper. The power consumed by the cavity while maintaining the beam's energy and its orbit is compensated by the 28MHz accelerating cavities in the storage ring. The power dissipation of the external load is dynamic with respect to the position of the FD during its extraction. As a function of the external Q and the EM field in the cavity, the power should peak with the FD at a certain vertical location. Our calculation of the power extracted is detailed in the following sections. Figure 2 plots the frequency change in the cavity, and the external Q against the changes in position of the FD. The location of the FD is selected carefully such that the frequency will approach the designed working point from the lower side only. The loaded Q of the cavity is 223 when the FD is fully

  20. Primary leiomyosarcoma of peritoneal cavity

    Directory of Open Access Journals (Sweden)

    Jyotsna Naresh Bharti

    2014-03-01

    Full Text Available Leiomyosarcomas of soft tissue are the rare tumors and the retroperitoneum is the most common site involved. We report a case of primary leiomyosarcoma of the peritoneal cavity which clinically presented with suprapubic, freely mobile, nontender mass which measured 10×10 cm in size. Contrast enhanced computed tomography revealed well defined heterogenous hypodense solid cystic mass. The mass was surgically excised out in its entirety. The histopathological examination revealed spindle cells arranged in alternating fascicles having pleomorphic nuclei, indistinct margin and eosinophilic cytoplasm with foci of haemorrhage, necrosis and 5-6 mitosis/HPF. The spindle cells were immunoreactive for smooth muscle actin, desmin and negative for S-100, CD-34 and c-kit. Histopathology and immunohistochemistry were helpful in making the final confirmatory diagnosis. Leiomyosarcomas are aggressive tumors, with poor prognosis and often difficult to treat. The survival rates are lowest among all soft tissue sarcomas.