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Sample records for resonant cavity radiator

  1. Characterization of the non-resonant radiation damping in coupled cavity photon magnon system

    Science.gov (United States)

    Rao, J. W.; Kaur, S.; Fan, X. L.; Xue, D. S.; Yao, B. M.; Gui, Y. S.; Hu, C.-M.

    2017-06-01

    We have experimentally investigated the non-resonant radiation damping in the coupled cavity photon-magnon system in addition to the resonant radiation damping which results in the linewidth exchange between the magnon-like and photon-like hybrid modes. The contribution of this non-resonant effect becomes apparent when the cavity photon-magnon resonance frequencies are mismatched. By carefully examining the change in the linewidth and the shift in the magnon resonance as a function of the coupling strength between the cavity photons and magnons, we can quantitatively describe this non-resonant radiation damping by including an additional relaxation channel for the hybridized photon-magnon system. This experimental realization and theoretical modelling of the non-resonant radiation damping in the cavity photon-magnon system may help in the design and adaptation of these systems for practical applications.

  2. 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.

  3. Radiation Characteristics of 3D Resonant Cavity Antenna with Grid-Oscillator Integrated Inside

    Directory of Open Access Journals (Sweden)

    L. A. Haralambiev

    2014-01-01

    Full Text Available A three-dimensional (3D rectangular cavity antenna with an aperture size of 80 mm × 80 mm and a length of 16 mm, integrated with a four-MESFET transistor grid-oscillator, is designed and studied experimentally. It is found that the use of 3D antenna resonant cavity in case of small or medium gain microwave active cavity antenna leads to effective and stable power combining and radiation. The lack of lateral cavity diffraction and radiation helps in producing a directive gain of about 17 dB and radiation aperture efficiency bigger than 75% at a resonance frequency of 8.62 GHz. Good DC to RF oscillator efficiency of 26%, effective isotropic radiated power (EIRP of 5.2 W, and SSB spectral power density of −82 dBc/Hz are found from the measured data. The 3D antenna cavity serves also as a strong metal container for the solid-state oscillator circuitry.

  4. RESONANT CAVITY EXCITATION SYSTEM

    Science.gov (United States)

    Baker, W.R.; Kerns, Q.A.; Riedel, J.

    1959-01-13

    An apparatus is presented for exciting a cavity resonator with a minimum of difficulty and, more specifically describes a sub-exciter and an amplifier type pre-exciter for the high-frequency cxcitation of large cavities. Instead of applying full voltage to the main oscillator, a sub-excitation voltage is initially used to establish a base level of oscillation in the cavity. A portion of the cavity encrgy is coupled to the input of the pre-exciter where it is amplified and fed back into the cavity when the pre-exciter is energized. After the voltage in the cavity resonator has reached maximum value under excitation by the pre-exciter, full voltage is applied to the oscillator and the pre-exciter is tunned off. The cavity is then excited to the maximum high voltage value of radio frequency by the oscillator.

  5. 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 hi

  6. Coupled resonator vertical cavity laser

    Energy Technology Data Exchange (ETDEWEB)

    Choquette, K.D.; Chow, W.W.; Hou, H.Q.; Geib, K.M.; Hammons, B.E.

    1998-01-01

    The monolithic integration of coupled resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the interaction between the cavities. The authors report the first electrically injected coupled resonator vertical-cavity laser diode and demonstrate novel characteristics arising from the cavity coupling, including methods for external modulation of the laser. A coupled mode theory is used model the output modulation of the coupled resonator vertical cavity laser.

  7. 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.

  8. Composite resonator vertical cavity laser diode

    Energy Technology Data Exchange (ETDEWEB)

    Choquette, K.D.; Hou, H.Q.; Chow, W.W.; Geib, K.M.; Hammons, B.E.

    1998-05-01

    The use of two coupled laser cavities has been employed in edge emitting semiconductor lasers for mode suppression and frequency stabilization. The incorporation of coupled resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the interaction between the cavities. Composite resonators can be utilized to control spectral and temporal properties within the laser; previous studies of coupled cavity vertical cavity lasers have employed photopumped structures. The authors report the first composite resonator vertical cavity laser diode consisting of two optical cavities and three monolithic distributed Bragg reflectors. Cavity coupling effects and two techniques for external modulation of the laser are described.

  9. Coupled Resonator Vertical Cavity Laser Diode

    Energy Technology Data Exchange (ETDEWEB)

    CHOQUETTE, KENT D.; CHOW, WENG W.; FISCHER, ARTHUR J.; GEIB, KENT M.; HOU, HONG Q.

    1999-09-16

    We report the operation of an electrically injected monolithic coupled resonator vertical cavity laser which consists of an active cavity containing In{sub x}Ga{sub 1{minus}x}As quantum wells optically coupled to a passive GaAs cavity. This device demonstrates novel modulation characteristics arising from dynamic changes in the coupling between the active and passive cavities. A composite mode theory is used to model the output modulation of the coupled resonator vertical cavity laser. It is shown that the laser intensity can be modulated by either forward or reverse biasing the passive cavity. Under forward biasing, the modulation is due to carrier induced changes in the refractive index, while for reverse bias operation the modulation is caused by field dependent cavity enhanced absorption.

  10. Coupled Resonator Vertical Cavity Laser Diodes

    Energy Technology Data Exchange (ETDEWEB)

    Choquette, K.D.; Chow, W.W.; Fischer, A.J.; Allerman, A.A.; Hou, H.Q.; Geib, K.M.

    1999-07-22

    For many applications, the device performance of edge emitting semiconductor lasers can be significantly improved through the use of multiple section devices. For example, cleaved coupled cavity (C3) lasers have been shown to provide single mode operation, wavelength tuning, high speed switching, as well as the generation of short pulses via mode-locking and Q-switching [1]. Using composite resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the coupling between the monolithic cavities, incorporate passive or active resonators which are spectrally degenerate or detuned, and to fabricate these devices in 2-dimensional arrays. Composite resonator vertical cavity lasers (CRVCL) have been examined using optical pumping and electrical injection [2-5]. We report on CRVCL diodes and show that efficient modulation of the laser emission can be achieved by either forward or reverse biasing the passive cavity within a CRVCL.

  11. Spectral investigation of hot-spot and cavity resonance effects on the terahertz radiation emitted from high-Tc superconducting Bi2Sr2CaCu2O8+δ single crystal mesa structures

    Science.gov (United States)

    Kadowaki, Kazuo; Watanabe, Chiharu; Minami, Hidetoshi; Yamamoto, Takashi; Kashiwagi, Takanari; Klemm, Richard

    2014-03-01

    Terahertz (THz) electromagnetic radiation emitted from high-Tc superconducting Bi2Sr2CaCu2O8+δ mesa structures in the case of single mesa and series-connected mesas is investigated by the FTIR spectroscopic technique while observing its temperature distribution simultaneously by a SiC photoluminescence technique. Changing the bias level, sudden jumps of the hot-spot position were clearly observed. Although the radiation intensity changes drastically associated with the jump of the hot spot position, the frequency is unaffected as long as the voltage per junction is kept constant. Since the frequency of the intense radiation satisfies the cavity resonance condition, we confirmed that the cavity resonance is of primarily importance for the synchronization of whole intrinsic Josephson junctions in the mesa for high power radiation. This work was supported in part by the Grant-in-Aid for challenging Exploratory Research, the Ministry of Education, Culture, Sports, Science & Technology (MEXT).

  12. Hyperbolic Resonances of Metasurface Cavities

    CERN Document Server

    Keene, David

    2015-01-01

    We propose a new class of optical resonator structures featuring one or two metasurface reflectors or metacavities and predict that such resonators support novel hyperbolic resonances. As an example of such resonances we introduce hyperbolic Tamm plasmons (HTPs) and hyperbolic Fabry-Perot resonances (HFPs). The hyperbolic optical modes feature low-loss incident power re-distribution over TM and TE polarization output channels, clover-leaf anisotropic dispersion, and other unique properties which are tunable and are useful for multiple applications.

  13. Reduction in Depth for a Radiating Flange Backed by a Rectangular Resonant Cavity Using High Index Materials: Preliminary Report

    Science.gov (United States)

    2013-09-01

    All simulations have been run using the time domain solver of CST Studio Suite 2012, and adaptive meshing has been used to verify convergence in the...figures 6 and 7 in. a0 b a1 fc (MHz) d δ PW 30.68 13.64 9.7 192.5 4.1 0.27 0.7 7 3.1 Isotropic Materials When εr > 1 and μr > 1 this...μx = 10, μy = 1, and μz = 1. 13 Table 4. Cavity dimensions for figure 8 in inches. a0 b a1 fc (MHz) d δ PW L 26.25 11.7 8.3 225 4.2 0.29

  14. 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...

  15. Piezoelectric Voltage Coupled Reentrant Cavity Resonator

    CERN Document Server

    Carvalho, Natalia C; Floch, Jean-Michel Le; Tobar, Michael Edmund

    2014-01-01

    A piezoelectric voltage coupled microwave reentrant cavity has been developed. The central cavity post is bonded to a piezoelectric actuator allowing the voltage control of small post displacements over a high dynamic range. We show that such a cavity can be implemented as a voltage tunable resonator, a transducer for exciting and measuring mechanical modes of the structure and a transducer for measuring comparative sensitivity of the piezoelectric material. Experiments were conducted at room and cryogenic temperatures with results verified using Finite Element software.

  16. Resonance Radiation and Excited Atoms

    Science.gov (United States)

    Mitchell, Allan C. G.; Zemansky, Mark W.

    2009-06-01

    1. Introduction; 2. Physical and chemical effects connected with resonance radiation; 3. Absorption lines and measurements of the lifetime of the resonance state; 4. Collision processes involving excited atoms; 5. The polarization of resonance radiation; Appendix; Index.

  17. Stafne bone cavity--magnetic resonance imaging.

    Science.gov (United States)

    Segev, Yoram; Puterman, Max; Bodner, Lipa

    2006-07-01

    A case of Stafne bone cavity (SBC) affecting the body of the mandible of a 51-year-old female is reported. The imaging modalities included panoramic radiograph, computed tomography (CT) and magnetic resonance (MR) imaging. Panoramic radiograph and CT were able to determine the outline of the cavity and its three dimensional shape, but failed to precisely diagnose the soft tissue content of the cavity. MR imaging demonstrated that the bony cavity is filled with soft tissue that is continuous and identical in signal with that of the submandibular salivary gland. Based on the MR imaging a diagnosis of SBC was made and no further studies or surgical treatment were initiated. MR imaging should be considered the diagnostic technique in cases where SBC is suspected. Recognition of the lesion should preclude any further treatment or surgical exploration.

  18. Coupled resonator induced transparency in surface plasmon polariton gap waveguide with two side-coupled cavities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhengren, E-mail: zhrenzhang@126.com [School of Science, Chongqing Jiaotong University, Chongqing 400074 (China); Zhang, Liwei [School of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Yin, Pengfei; Han, Xiangyu [School of Science, Chongqing Jiaotong University, Chongqing 400074 (China)

    2014-08-01

    We investigate theoretically the generation process of coupled resonator-induced transparency (CRIT) in surface plasmon polariton gap waveguide system containing two side-coupled cavities, which locate at a symmetric position. The CRIT is original from the destructive interference of the two detuned cavities. In contrast with the existing electromagnetically induced transparency (EIT) schemes, the occurrence of the CRIT is caused by the two radiative cavities in waveguide, instead of interference between a dark cavity and radiative cavity. This behavior mimics the quantum interference between two direct excitation pathways in a three-level V-type atom. The transmission lineshape can be tuned between an EIT-like resonant peak and a Lorentzian-like resonant dip by tailoring the detuning of the two cavities. Moreover, we also find that the transparency peak moves to high frequency with a line shift and its Q factor decreases with the increase of coupling distance between the cavities and waveguide.

  19. Optical cavity resonator in an expanding universe

    Science.gov (United States)

    Kopeikin, Sergei M.

    2015-02-01

    We study the cosmological evolution of frequency of a standing electromagnetic wave in a resonant optical cavity placed to the expanding manifold described by the Robertson-Walker metric. Because of the Einstein principle of equivalence (EEP), one can find a local coordinate system (a local freely falling frame), in which spacetime is locally Minkowskian. However, due to the conformal nature of the Robertson-Walker metric the conventional transformation to the local inertial coordinates introduces ambiguity in the physical interpretation of the local time coordinate, . Therefore, contrary to a common-sense expectation, a straightforward implementation of EEP alone does not allow us to unambiguously decide whether atomic clocks based on quantum transitions of atoms, ticks at the same rate as the clocks based on electromagnetic modes of a cavity. To resolve this ambiguity we have to analyse the cavity rigidity and the oscillation of its electromagnetic modes in an expanding universe by employing the full machinery of the Maxwell equations irrespectively of the underlying theory of gravity. We proceed in this way and found out that the size of the cavity and the electromagnetic frequency experience an adiabatic drift in conformal (unphysical) coordinates as the universe expands in accordance with the Hubble law. We set up the oscillation equation for the resonant electromagnetic modes, solve it by the WKB approximation, and reduce the coordinate-dependent quantities to their counterparts measured by a local observer who counts time with atomic clock. The solution shows that there is a perfect mutual cancellation of the adiabatic drift of cavity's frequency by space transformation to local coordinates and the time counted by the clocks based on electromagnetic modes of cavity has the same rate as that of atomic clocks. We conclude that if general relativity is correct and the local expansion of space is isotropic there should be no cosmological drift of frequency of a

  20. Resonant cavity monitors for charged beam measurements.

    Science.gov (United States)

    Rutledge, Gary A.

    2003-04-01

    The G_zero experiment at Jefferson Lab, will measure the strange quark content of the proton as it contributes to the proton's charge and magnetic properties. Parity violating elastic electron scattering is being used to measure the physics asymmetry to better than 1 part in 10^7. Helicity correlated properties of the electron beam used in this experiment must be measured to better than 1 in 10^7 over the course of the experiment. G_zero employs two types of beam monitors for this purpose. Standard, 4-wire, ``strip-line'' monitors measure beam positions with a resolution of 20microns. Another type of monitor, Beam Resonant Cavities are being tested. Two sets of three cavities are used to measure beam position in X and Y, as well as beam current. Presented will be the performance and evaluation of these cavities including their theoretical versus actual operation, their noise characteristics, and signal resolution. These cavities can be paired with either linear or logarithmic amplifier electronics. Overall performance of these cavity systems including amplifiers will be compared with standard 'strip-line' monitors.

  1. Observation of generalized optomechanical coupling and cooling on cavity resonance.

    Science.gov (United States)

    Sawadsky, Andreas; Kaufer, Henning; Nia, Ramon Moghadas; Tarabrin, Sergey P; Khalili, Farid Ya; Hammerer, Klemens; Schnabel, Roman

    2015-01-30

    Optomechanical coupling between a light field and the motion of a cavity mirror via radiation pressure plays an important role for the exploration of macroscopic quantum physics and for the detection of gravitational waves (GWs). It has been used to cool mechanical oscillators into their quantum ground states and has been considered to boost the sensitivity of GW detectors, e.g., via the optical spring effect. Here, we present the experimental characterization of generalized, that is, dispersive and dissipative, optomechanical coupling, with a macroscopic (1.5  mm)2-size silicon nitride membrane in a cavity-enhanced Michelson-type interferometer. We report for the first time strong optomechanical cooling based on dissipative coupling, even on cavity resonance, in excellent agreement with theory. Our result will allow for new experimental regimes in macroscopic quantum physics and GW detection.

  2. Observation of generalized optomechanical coupling and cooling on cavity resonance

    CERN Document Server

    Sawadsky, Andreas; Nia, Ramon Moghadas; Tarabrin, Sergey P; Khalili, Farid Ya; Hammerer, Klemens; Schnabel, Roman

    2014-01-01

    Optomechanical coupling between a light field and the motion of a cavity mirror via radiation pressure plays an important role for the exploration of macroscopic quantum physics and for the detection of gravitational waves (GWs). It has been used to cool mechanical oscillators into their quantum ground states and has been considered to boost the sensitivity of GW detectors, e.g. via the optical spring effect. Here, we present the experimental characterization of generalized, that is, dispersive and dissipative optomechanical coupling, with a macroscopic (1.5mm)^2-sized silicon nitride (SiN) membrane in a cavity-enhanced Michelson-type interferometer. We report for the first time strong optomechanical cooling based on dissipative coupling, even on cavity resonance, in excellent agreement with theory. Our result will allow for new experimental regimes in macroscopic quantum physics and GW detection.

  3. 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.

  4. Plasmonic-cavity model for radiating nano-rod antennas.

    Science.gov (United States)

    Peng, Liang; Mortensen, N Asger

    2014-01-23

    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.

  5. Optical cavity resonator in an expanding universe

    CERN Document Server

    Kopeikin, Sergei

    2014-01-01

    We study evolution of frequency of a standing electromagnetic (EM) wave in a resonant optical cavity placed to the expanding manifold described by the Robertson-Walker metric. One builds a local coordinate system in which spacetime is locally Minkowskian. However, due to the conformal nature of the Robertson-Walker metric the conventional transformation to the local inertial coordinates introduces ambiguity in the physical interpretation of the local time coordinate. Therefore, contrary to a common-sense expectation, a straightforward implementation of EEP alone does not allow us to decide whether atomic clocks ticks at the same rate as the clocks based on EM modes of a cavity. To resolve the ambiguity we analyzed the cavity rigidity and the oscillation of its EM modes in an expanding universe by employing the Maxwell equations. We found out that both the size of the cavity and the EM frequency experience an adiabatic drift in conformal coordinates as the universe expands. We set up the oscillation equation f...

  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. Tunable cavity resonator including a plurality of MEMS beams

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Dispersive radiation induced by shock waves in passive resonators.

    Science.gov (United States)

    Malaguti, Stefania; Conforti, Matteo; Trillo, Stefano

    2014-10-01

    We show that passive Kerr resonators pumped close to zero dispersion wavelengths on the normal dispersion side can develop the resonant generation of linear waves driven by cavity (mixed dispersive-dissipative) shock waves. The resonance mechanism can be successfully described in the framework of the generalized Lugiato-Lefever equation with higher-order dispersive terms. Substantial differences with radiation from cavity solitons and purely dispersive shock waves dispersion are highlighted.

  9. Theory of RF superconductivity for resonant cavities

    Science.gov (United States)

    Gurevich, Alex

    2017-03-01

    An overview of a theory of electromagnetic response of superconductors in strong radio-frequency (RF) electromagnetic fields is given with the emphasis on applications to superconducting resonant cavities for particle accelerators. The paper addresses fundamentals of the BCS surface resistance, the effect of subgap states and trapped vortices on the residual surface resistance at low RF fields, and a nonlinear surface resistance at strong fields, particularly the effect of the RF field suppression of the surface resistance. These issues are essential for the understanding of the field dependence of high quality factors Q({B}a)∼ {10}10{--}{10}11 achieved on the Nb cavities at 1.3–2 K in strong RF fields B a close to the depairing limit, and the extended Q({B}a) rise which has been observed on Ti and N-treated Nb cavities. Possible ways of further increase of Q({B}a) and the breakdown field by optimizing impurity concentration at the surface and by multilayer nanostructuring with materials other than Nb are discussed.

  10. THz parallel-plate waveguides with resonant cavities

    DEFF Research Database (Denmark)

    Reichel, Kimberly S.; Astley, Victoria; Iwaszczuk, Krzysztof;

    2015-01-01

    We characterize the terahertz resonance due to a cavity inside aparallel-plate waveguide, and discuss its use for refractive index sensing. Insidethe waveguide, we observe a broadband field enhancement associated with thisnarrowband resonance. © 2015 OSA....

  11. Cavity optomechanics on a microfluidic resonator

    CERN Document Server

    Kim, Kyu Hyun; Lee, Wonsuk; Liu, Jing; Tomes, Matthew; Fan, Xudong; Carmon, Tal

    2012-01-01

    Light pressure is known to excite or cool vibrations in microresonators for sensing quantum-optomechanical effects and we now show that it can be explored for investigations with liquids. Currently, optical resonances are utilized to detect analytes in liquids. However, optomechanical oscillations have never been excited when devices were immersed in liquid. This is because replacing the surrounding air with water inherently increases the acoustical impedance and the associated acoustical-radiation losses. Here we fabricate a hollow optomechanical bubble resonator with water inside, and use light pressure to excite 8 MHz - 140 MHz vibrations with 1 mW optical-threshold power and >2000 mechanical Q, constituting the first time that any microfluidic system is optomechanically actuated. Bridging between optomechanics and microfluidics will enable recently developed capillaries and on-chip bubbles to vibrate via optical excitation; and allow optomechanics with non-solid material phases including bio-analytes, sup...

  12. Ferrite-filled cavities for compact planar resonators

    Science.gov (United States)

    Keatley, P. S.; Durrant, C. J.; Berry, S. J.; Sirotkin, E.; Hibbins, A. P.; Hicken, R. J.

    2014-01-01

    Sub-wavelength metallic planar cavities, closed at one end, have been constructed by wrapping aluminium foil around teflon or ferrite slabs. Finite cavity width perturbs the fundamental cavity mode frequency of ferrite-filled cavities due to different permeability inside and outside of the cavity, in contrast to teflon-filled cavities, while the cavity length required to achieve a specific resonance frequency is significantly reduced for a ferrite-filled cavity. Ferrite-filled cavities may be excited by an in-plane alternating magnetic field and may be advantageous for high-frequency (HF) and ultra HF tagging and radio frequency identification of metallic objects within security, manufacturing, and shipping environments.

  13. Resonance Photon Generation in a Vibrating Cavity

    CERN Document Server

    Dodonov, V V

    1998-01-01

    The problem of photon creation from vacuum due to the nonstationary Casimir effect in an ideal one-dimensional Fabry--Perot cavity with vibrating walls is solved in the resonance case, when the frequency of vibrations is close to the frequency of some unperturbed electromagnetic mode: $\\omega_w=p(\\pi c/L_0)(1+\\delta)$, $|\\delta|\\ll 1$, (p=1,2,...). An explicit analytical expression for the total energy in all the modes shows an exponential growth if $|\\delta|$ is less than the dimensionless amplitude of vibrations $\\epsilon\\ll 1$, the increment being proportional to $p\\sqrt{\\epsilon^2-\\delta^2}$. The rate of photon generation from vacuum in the (j+ps)th mode goes asymptotically to a constant value $cp^2\\sin^2(\\pi j/p)\\sqrt{\\epsilon^2-\\delta^2}/[\\pi L_0 (j+ps)]$, the numbers of photons in the modes with indices p,2p,3p,... being the integrals of motion. The total number of photons in all the modes is proportional to $p^3(\\epsilon^2-\\delta^2) t^2$ in the short-time and in the long-time limits. In the case of st...

  14. 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.

  15. 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).

  16. Feedback-free optical cavity with self-resonating mechanism

    CERN Document Server

    Uesugi, Y; Honda, Y; Kosuge, A; Omori, T; Takahashi, T; Urakawa, J; Washio, M

    2015-01-01

    We demonstrated the operation of a high finesse optical cavity without utilizing an active feedback system to stabilize the resonance. The finesse of the cavity was measured to be $465,000 \\pm 3,000$, and the laser power stored in the cavity was $2.52 \\pm 0.13$ kW, which is about 187,000 times greater than the incident power to the cavity. The stored power was stabilized with a fluctuation of $1.7 \\%$, and we confirmed continuous cavity operation for more than two hours. This result relaxes the technical requirement of stabilizing of the optical resonant cavity and expands possibilities for various applications such as laser-Compton scattering.

  17. Perturbing Open Cavities: Anomalous Resonance Frequency Shifts in a Hybrid Cavity-Nanoantenna System

    Science.gov (United States)

    Ruesink, Freek; Doeleman, Hugo M.; Hendrikx, Ruud; Koenderink, A. Femius; Verhagen, Ewold

    2015-11-01

    The influence of a small perturbation on a cavity mode plays an important role in fields like optical sensing, cavity quantum electrodynamics, and cavity optomechanics. Typically, the resulting cavity frequency shift directly relates to the polarizability of the perturbation. Here, we demonstrate that particles perturbing a radiating cavity can induce strong frequency shifts that are opposite to, and even exceed, the effects based on the particles' polarizability. A full electrodynamic theory reveals that these anomalous results rely on a nontrivial phase relation between cavity and nanoparticle radiation, allowing backaction via the radiation continuum. In addition, an intuitive model based on coupled mode theory is presented that relates the phenomenon to retardation. Because of the ubiquity of dissipation, we expect these findings to benefit the understanding and engineering of a wide class of systems.

  18. Perturbing open cavities: Anomalous resonance frequency shifts in a hybrid cavity-nanoantenna system

    CERN Document Server

    Ruesink, Freek; Hendrikx, Ruud; Koenderink, A Femius; Verhagen, Ewold

    2015-01-01

    The influence of a small perturbation on a cavity mode plays an important role in fields like optical sensing, cavity quantum electrodynamics and cavity optomechanics. Typically, the resulting cavity frequency shift directly relates to the polarizability of the perturbation. Here we demonstrate that particles perturbing a radiating cavity can induce strong frequency shifts that are opposite to, and even exceed, the effects based on the particles' polarizability. A full electrodynamic theory reveals that these anomalous results rely on a non-trivial phase relation between cavity and nanoparticle radiation, allowing back-action via the radiation continuum. In addition, an intuitive model based on coupled mode theory is presented that relates the phenomenon to retardation. Because of the ubiquity of dissipation, we expect these findings to benefit the understanding and engineering of a wide class of systems.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    A hybrid III–V/SOI resonant-cavity-enhanced photodetector (RCE-PD) structure comprising a high-contrast grating (HCG) reflector, a hybrid grating (HG) reflector, and an air cavity between them, has been proposed and investigated. In the proposed structure, a light absorbing material is integrated...

  20. Systematization of All Resonance Modes in Circular Dielectric Cavities

    NARCIS (Netherlands)

    Dettmann, C.P.; Morozov, G.V.; Sieber, M.; Waalkens, H.

    2009-01-01

    Circular dielectric cavities are key components for the construction of optic microresonators and microlasers. They are one of very few cases where the transcendental equations for complex eigenmodes (resonances) of an open system (dielectric cavity) can be found analytically in an exact manner. The

  1. High Quality RF resonant cavity for high gradient linacs

    CERN Document Server

    TianXiu-fang,; Deguo, Xun; Kun, Liu; yong, Hou; Jian, Cheng

    2015-01-01

    In traditional accelerating structures, maximum amplitudes of accelerating fields are restricted by Joule heating losses in conducting walls and electron breakdown. In this paper, a composite accelerating cavity utilizing a resonant, periodic structure with a dielectric sphere located at a spherical conducting cavity center is presented. The presence of the dielectric in the central part of the resonance cavity shifts the magnetic fields maximum from regions close to the metallic wall towards the dielectric surface, which strongly lowers the skin effect losses in the wall. By using the existing ultra-low loss Sapphire dielectrics, we make theory analyze and numerical calculations by MATLAB, and further make simulated calculation by CST for comparison. The results show that all field components at the metallic wall are either zero or very small, so one can expect the cavity to be less prone to electrical breakdowns than the traditional cavity. And the quality factor Q can be three orders of magnitude higher th...

  2. Einstein-Maxwell equations for asymmetric resonant cavities

    CERN Document Server

    Frasca, Marco

    2015-01-01

    We analyze the behavior of electromagnetic fields inside a resonant cavity by solving Einstein--Maxwell field equations. It is shown that the modified geometry of space-time inside the cavity due to a propagating mode can affect the propagation of a laser beam. It is seen that components of laser light with a shifted frequency appear originating from the coupling between the laser field and the mode cavity due to gravity. The analysis is extended to the case of an asymmetric resonant cavity taken to be a truncated cone. It is shown that a proper choice of the geometrical parameters of the cavity and dielectric can make the gravitational effects significant for an interferometric setup. This could make possible to realize table-top experiments involving gravitational effects.

  3. Ray and wave chaos in asymmetric resonant optical cavities

    CERN Document Server

    Nöckel, J U; Noeckel, Jens U.

    1998-01-01

    Optical resonators are essential components of lasers and other wavelength-sensitive optical devices. A resonator is characterized by a set of modes, each with a resonant frequency omega and resonance width Delta omega=1/tau, where tau is the lifetime of a photon in the mode. In a cylindrical or spherical dielectric resonator, extremely long-lived resonances are due to `whispering gallery' modes in which light circulates around the perimeter trapped by total internal reflection. These resonators emit light isotropically. Recently, a new category of asymmetric resonant cavities (ARCs) has been proposed in which substantial shape deformation leads to partially chaotic ray dynamics. This has been predicted to give rise to a universal, frequency-independent broadening of the whispering-gallery resonances, and highly anisotropic emission. Here we present solutions of the wave equation for ARCs which confirm many aspects of the earlier ray-optics model, but also reveal interesting frequency-dependent effects charac...

  4. Adiabatic embedment of nanomechanical resonators in photonic microring cavities

    CERN Document Server

    Xiong, Chi; Li, Mo; Rooks, Michael; Tang, Hong X

    2014-01-01

    We report a circuit cavity optomechanical system in which a nanomechanical resonator is adiabatically embedded inside an optical ring resonator with ultralow transition loss. The nanomechanical device forms part of the top layer of a horizontal silicon slot ring resonator, which enables dispersive coupling to the dielectric substrate via a tapered nanogap. Our measurements show nearly uncompromised optical quality factors (Q) after the release of the mechanical beam.

  5. Fano resonance engineering in slanted cavities with hyperbolic metamaterials

    Science.gov (United States)

    Vaianella, Fabio; Maes, Bjorn

    2016-09-01

    We present the possibility to engineer Fano resonances using multilayered hyperbolic metamaterials. The proposed cavity designs are composed of multilayers with a central slanted part. The highly tunable resonances originate from the interference between a propagating and an evanescent mode inside the slanted section. The propagating mode can reach an extremely high effective index, making the realization of deeply subwavelength cavities possible, as small as 5 nm. The evanescent mode is rarely analyzed but plays an important role here, as its contribution determines the particular shape of the cavity characteristic. Moreover, these phenomena cannot be described using effective medium theory, and we provide a more rigorous analysis. The reported resonances are very sensitive to any structural changes and could be used for sensing applications.

  6. Indirect Coupling between Two Cavity Photon Systems via Ferromagnetic Resonance

    CERN Document Server

    Hyde, Paul; Harder, Michael; Match, Christophe; Hu, Can-Ming

    2016-01-01

    We experimentally realize indirect coupling between two cavity modes via strong coupling with the ferromagnetic resonance in Yttrium Iron Garnet (YIG). We find that some indirectly coupled modes of our system can have a higher microwave transmission than the individual uncoupled modes. Using a coupled harmonic oscillator model, the influence of the oscillation phase difference between the two cavity modes on the nature of the indirect coupling is revealed. These indirectly coupled microwave modes can be controlled using an external magnetic field or by tuning the cavity height. This work has potential for use in controllable optical devices and information processing technologies.

  7. Optical cavity coupled surface plasmon resonance sensing for enhanced sensitivity

    Institute of Scientific and Technical Information of China (English)

    Zheng Zheng; Xin Zhao; Jinsong Zhu; Jim Diamond

    2008-01-01

    A surface plasmon resonance (SPR) sensing system based on the optical cavity enhanced detection tech-nique is experimentally demonstrated. A fiber-optic laser cavity is built with a SPR sensor inside. By measuring the laser output power when the cavity is biased near the threshold point, the sensitivity, defined as the dependence of the output optical intensity on the sample variations, can be increased by about one order of magnitude compared to that of the SPR sensor alone under the intensity interrogation scheme. This could facilitate ultra-high sensitivity SPR biosensing applications. Further system miniaturization is possible by using integrated optical components and waveguide SPR sensors.

  8. Nonradiating and radiating modes excited by quantum emitters in open epsilon-near-zero cavities

    CERN Document Server

    Liberal, Iñigo

    2015-01-01

    Controlling the emission and interaction properties of quantum emitters (QEs) embedded within an optical cavity is a key technique in engineering light-matter interactions at the nanoscale, as well as in the development of quantum information processing. State-of-the-art optical cavities are based on high Q photonics crystals and dielectric resonators. However, wealthier responses might be attainable with cavities carved in more exotic materials. Here, we theoretically investigate the emission and interaction properties of QEs embedded in open epsilon-near-zero (ENZ) cavities. Using analytical methods and numerical simulations, it is demonstrated that open ENZ cavities present the unique property of supporting nonradiating modes independently of the geometry of the external boundary of the cavity (shape, size, topology...). Moreover, the possibility of switching between radiating and nonradiating modes enables a dynamic control of both the emission by, and the interaction between, QEs. These phenomena provide...

  9. Silicon waveguide polarization rotation Bragg grating with resonator cavity section

    Science.gov (United States)

    Okayama, Hideaki; Onawa, Yosuke; Shimura, Daisuke; Yaegashi, Hiroki; Sasaki, Hironori

    2017-04-01

    Bragg grating with resonator cavity that converts the input polarization to orthogonal polarization is reported. The device works similar to a Fabry–Pérot or ring resonators and very narrow polarization independent wavelength peak can be generated. The transfer matrix methods are used to examine the device characteristics. A 0.2-nm-wide polarization independent transmission wavelength peak was obtained by experiment. We also show theoretically using finite-difference-time-domain method that a flat-top response can be obtained by a two cavity structure.

  10. Electromagnetic coupling to centimeter-scale mechanical membrane resonators via RF cylindrical cavities

    Science.gov (United States)

    Martinez, Luis A.; Castelli, Alessandro R.; Delmas, William; Sharping, Jay E.; Chiao, Raymond

    2016-11-01

    We present experimental and theoretical results for the excitation of a mechanical oscillator via radiation pressure with a room-temperature system employing a relatively low-(Q) centimeter-size mechanical oscillator coupled to a relatively low-Q standard three-dimensional radio-frequency (RF) cavity resonator. We describe the forces giving rise to optomechanical coupling using the Maxwell stress tensor and show that nanometer-scale displacements are possible and experimentally observable. The experimental system is composed of a 35 mm diameter silicon nitride membrane sputtered with a 300 nm gold conducting film and attached to the end of a RF copper cylindrical cavity. The RF cavity is operated in its {{TE}}011 mode and amplitude modulated on resonance with the fundamental drum modes of the membrane. Membrane motion is monitored using an unbalanced, non-zero optical path difference, optically filtered Michelson interferometer capable of measuring sub-nanometer displacements.

  11. Geometric stochastic resonance in a double cavity

    CERN Document Server

    Ghosh, Pulak K; Marchesoni, Fabio; Savel'ev, Sergey E; Nori, Franco; 10.1103/PhysRevE.84.011109

    2012-01-01

    Geometric stochastic resonance of particles diffusing across a porous membrane subject to oscillating forces is characterized as a synchronization process. Noninteracting particle currents through a symmetric membrane pore are driven either perpendicular or parallel to the membrane, whereas harmonic-mixing spectral current components are generated by the combined action of perpendicular and parallel drives. In view of potential applications to the transport of colloids and biological molecules through narrow pores, we also consider the role of particle repulsion as a controlling factor.

  12. 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....

  13. Temperature compensation of resonant cavities with a teflon post

    OpenAIRE

    1982-01-01

    The negative temperature coefficient of E for teflon is used to compensate the frequency drift of a metal cavity due to thermal expansion. An experimental X-band transmission resonator was compensated in this way with a 10 mm teflon post. The results are considered of great interest for the compensation of waveguide millimiter wave oscillators. Peer Reviewed

  14. RESONANCE RADIATION OF SUBMERGED INFINITE CYLINDRICAL SHELL

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The resonance sound radiation from submerged infinite elastic cylindrical shell, excited by internal harmonic line force, is investigated. The shell radiation power is presented in terms of resonant modal radiation derived from resonance radiation theory (RRT). The resonance radiation formulae are derived from classical Rayleigh normal mode solution, which are useful for understanding the mechanism of sound radiation from submerged shells. As an example, numerical calculation of a thin steel cylindrical shell is done by using these two methods. It seems that the results of RRT solutions are in good agreement with that of Rayleigh normal mode solutions.

  15. Low loss optical waveguide crossing based on octagonal resonant cavity coupling

    Institute of Scientific and Technical Information of China (English)

    Mohd. Zahed M. Khan

    2009-01-01

    A waveguide crossing utilizing a high index contrast material system is presented. The structure is based on coupling with an octagonal resonant cavity inscrted at the waveguide junction. It also employs four identical square metal strips placed at the four comers of the waveguide crossing. The spectral response of the structure calculated using the method of line numerical technique, in general, shows a high power transmission in the forward arm with sufficiently low crosstalk and fraction of radiated power.

  16. Performance study of cavity-backed dual-band radiators

    NARCIS (Netherlands)

    Amaldoss, S.E.; Yarovoy, A.

    2011-01-01

    The effectiveness of a cavity for dual-band patch radiator with a frequency ratio of 1.65:1 is analysed. The use of cavities can help in maintaining impedance matching, reducing the levels of mutual coupling between the elements as well as in containing the surface waves, aspects vital to array perf

  17. Scalable high-precision tuning of photonic resonators by resonant cavity-enhanced photoelectrochemical etching

    Science.gov (United States)

    Gil-Santos, Eduardo; Baker, Christopher; Lemaître, Aristide; Gomez, Carmen; Leo, Giuseppe; Favero, Ivan

    2017-01-01

    Photonic lattices of mutually interacting indistinguishable cavities represent a cornerstone of collective phenomena in optics and could become important in advanced sensing or communication devices. The disorder induced by fabrication technologies has so far hindered the development of such resonant cavity architectures, while post-fabrication tuning methods have been limited by complexity and poor scalability. Here we present a new simple and scalable tuning method for ensembles of microphotonic and nanophotonic resonators, which enables their permanent collective spectral alignment. The method introduces an approach of cavity-enhanced photoelectrochemical etching in a fluid, a resonant process triggered by sub-bandgap light that allows for high selectivity and precision. The technique is presented on a gallium arsenide nanophotonic platform and illustrated by finely tuning one, two and up to five resonators. It opens the way to applications requiring large networks of identical resonators and their spectral referencing to external etalons.

  18. Laser and cavity cooling of a mechanical resonator with a nitrogen-vacancy center in diamond

    Science.gov (United States)

    Giannelli, Luigi; Betzholz, Ralf; Kreiner, Laura; Bienert, Marc; Morigi, Giovanna

    2016-11-01

    We theoretically analyze the cooling dynamics of a high-Q mode of a mechanical resonator, when the structure is also an optical cavity and is coupled with a nitrogen-vacancy (NV) center. The NV center is driven by a laser and interacts with the cavity photon field and with the strain field of the mechanical oscillator, while radiation pressure couples the mechanical resonator and cavity field. Starting from the full master equation we derive the rate equation for the mechanical resonator's motion, whose coefficients depend on the system parameters and on the noise sources. We then determine the cooling regime, the cooling rate, the asymptotic temperatures, and the spectrum of resonance fluorescence for experimentally relevant parameter regimes. For these parameters, we consider an electronic transition, whose linewidth allows one to perform sideband cooling, and show that the addition of an optical cavity in general does not improve the cooling efficiency. We further show that pure dephasing of the NV center's electronic transitions can lead to an improvement of the cooling efficiency.

  19. High-Q 3D coaxial resonators for cavity QED

    Science.gov (United States)

    Yoon, Taekwan; Owens, John C.; Naik, Ravi; Lachapelle, Aman; Ma, Ruichao; Simon, Jonathan; Schuster, David I.

    Three-dimensional microwave resonators provide an alternative approach to transmission-line resonators used in most current circuit QED experiments. Their large mode volume greatly reduces the surface dielectric losses that limits the coherence of superconducting circuits, and the well-isolated and controlled cavity modes further suppress coupling to the environment. In this work, we focus on unibody 3D coaxial cavities which are only evanescently coupled and free from losses due to metal-metal interfaces, allowing us to reach extremely high quality-factors. We achieve quality-factor of up to 170 million using 4N6 Aluminum at superconducting temperatures, corresponding to an energy ringdown time of ~4ms. We extend our methods to other materials including Niobium, NbTi, and copper coated with Tin-Lead solder. These cavities can be further explored to study their properties under magnetic field or upon coupling to superconducting Josephson junction qubits, e.g. 3D transmon qubits. Such 3D cavity QED system can be used for quantum information applications, or quantum simulation in coupled cavity arrays.

  20. Electron Plasmas Cooled by Cyclotron-Cavity Resonance

    CERN Document Server

    Povilus, A P; Evans, L T; Evetts, N; Fajans, J; Hardy, W N; Hunter, E D; Martens, I; Robicheaux, F; Shanman, S; So, C; Wang, X; Wurtele, J S

    2016-01-01

    We observe that high-Q electromagnetic cavity resonances increase the cyclotron cooling rate of pure electron plasmas held in a Penning-Malmberg trap when the electron cyclotron frequency, controlled by tuning the magnetic field, matches the frequency of standing wave modes in the cavity. For certain modes and trapping configurations, this can increase the cooling rate by factors of ten or more. In this paper, we investigate the variation of the cooling rate and equilibrium plasma temperatures over a wide range of parameters, including the plasma density, plasma position, electron number, and magnetic field.

  1. Ultrabroadband super-Planckian radiative heat transfer with artificial continuum cavity states in patterned hyperbolic metamaterials

    Science.gov (United States)

    Dai, Jin; Ding, Fei; Bozhevolnyi, Sergey I.; Yan, Min

    2017-06-01

    Localized cavity resonances due to nanostructures at material surfaces can greatly enhance radiative heat transfer (RHT) between two closely placed bodies owing to stretching of cavity states in momentum space beyond the light line. Based on such understanding, we numerically demonstrate the possibility of ultrabroadband super-Planckian RHT between two plates patterned with trapezoidal-shaped hyperbolic metamaterial (HMM) arrays. The phenomenon is rooted not only in HMM's high effective index for creating subwavelength resonators but also its extremely anisotropic isofrequency contour. The two properties enable one to create photonic bands with a high spectral density to populate a desired thermal radiation window. At submicron gap sizes between such two plates, the artificial continuum states extend outside the light cone, tremendously increasing overall RHT. Our study reveals that structured HMM offers unprecedented potential in achieving a controllable super-Planckian radiative heat transfer for thermal management at nanoscale.

  2. Continuous ammonia monitor using a Stark microwave cavity resonator.

    Science.gov (United States)

    Uehara, H; Ijuuin, Y; Morino, Y; Kamidate, T; Nakamura, A; Imai, H

    1980-03-01

    An ammonia monitor has been made by using a rectangular Stark microwave cavity tightly coupled through an iris to a Gunn oscillator. The Stark electrode installed inside the cavity is provided with a 100 kHz sinusoidal modulation voltage and a dc sweep voltage. The oscillation of the Gunn diode is tuned with the coupled Stark cavity to a frequency near a J,K=3,3 transition (23870.1 MHz) of ammonia. By fixing the Stark dc bias to a voltage which gives a peak intensity of the derivative output of the electric-resonance signal, ammonia is continuously monitored. An extremely good long-term stability is obtained. The noise level corresponds to 0.08 ppm of ammonia.

  3. Quasistatic Cavity Resonance for Ubiquitous Wireless Power Transfer.

    Science.gov (United States)

    Chabalko, Matthew J; Shahmohammadi, Mohsen; Sample, Alanson P

    2017-01-01

    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.

  4. Quasistatic Cavity Resonance for Ubiquitous Wireless Power Transfer

    Science.gov (United States)

    Shahmohammadi, Mohsen; Sample, Alanson P.

    2017-01-01

    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. PMID:28199321

  5. Resonant-cavity based monolithic white light-emitting diode

    Science.gov (United States)

    Huang, Lirong; Huang, Dexiu; Wen, Feng

    2007-11-01

    We propose a new scheme of resonant-cavity (RC) based monolithic white LED, it relaxes the hard requirement of high internal quantum efficiency of yellow multi-quantum (MQW) and offers an easy way to obtain high luminous efficacy white light emission. In the proposed white LED, the blue MQW and yellow MQW active layer are embedded in a resonant-cavity defined by the bottom distributed Bragg reflector(DBR) and top DBR. For a optimal design of RC-based white LED, the extraction efficiency for yellow light is enhanced, while that for blue light is suppressed, thus intensity ratio of yellow light in the emitting light is increased, which not only helps to obtain white emission in spite of the low internal quantum efficiency of yellow light, but also doubles luminous efficacy. The color coordinates and luminous flux of the emitting light from RC-based white LED are calculated and the performance dependence on directionality is investigated.

  6. Resonance widths in open microwave cavities studied by harmonic inversion.

    Science.gov (United States)

    Kuhl, U; Höhmann, R; Main, J; Stöckmann, H-J

    2008-06-27

    From the measurement of a reflection spectrum of an open microwave cavity, the poles of the scattering matrix in the complex plane have been determined. The resonances have been extracted by means of the harmonic inversion method. By this, it became possible to resolve the resonances in a regime where the linewidths exceed the mean level spacing up to a factor of 10, a value inaccessible in experiments up to now. The obtained experimental distributions of linewidths were found to be in perfect agreement with predictions from random matrix theory when wall absorption and fluctuations caused by couplings to additional channels are considered.

  7. Resonance widths in open microwave cavities studied by harmonic inversion

    OpenAIRE

    Kuhl, U; Hoehmann, R.; Main, J.; Stoeckmann, H. -J.

    2007-01-01

    From the measurement of a reflection spectrum of an open microwave cavity the poles of the scattering matrix in the complex plane have been determined. The resonances have been extracted by means of the harmonic inversion method. By this it became possible to resolve the resonances in a regime where the line widths exceed the mean level spacing up to a factor of 10, a value inaccessible in experiments up to now. The obtained experimental distributions of line widths were found to be in perfec...

  8. Conditioning for the RF Resonant Cavities of the CYCIAE-100

    Institute of Scientific and Technical Information of China (English)

    YIN; Zhi-guo; JI; Bin; ZHAO; Zhen-lu; FU; Xiao-liang; LEI; Yu; WANG; Chuan; YANG; Jian-jun; WEI; Jun-yi; LI; Peng-zhan; LV; Yin-long; ZHANG; Tian-jue; GE; Tao; CAI; Hong-ru; PAN; Gao-feng; ZHU; Peng-fei; AN; Shi-zhong; XING; Jian-sheng; YIN; Meng; CAO; Lei; ZHANG; Su-ping; WEN; Li-peng; HOU; Shi-gang; WU; Long-cheng; LIU; Geng-shou; LI; Zhen-guo; CUI; Bai-yao; DONG; Huan-jun

    2013-01-01

    The CYCIAE-100 cyclotron developed by the BRIF project group had finished installation of its main equipments and parts in 2012.The field mapping of the main magnet has been done afterward.In Dec.13th,2012,the vacuum of the main chamber reached 4×10-7 mbar,conditioning for the RF resonant cavities were started shortly after.When the cyclotron is opened the interior surface is exposed to air and

  9. Hybrid circuit cavity quantum electrodynamics with a micromechanical resonator.

    Science.gov (United States)

    Pirkkalainen, J-M; Cho, S U; Li, Jian; Paraoanu, G S; Hakonen, P J; Sillanpää, M A

    2013-02-14

    Hybrid quantum systems with inherently distinct degrees of freedom have a key role in many physical phenomena. Well-known examples include cavity quantum electrodynamics, trapped ions, and electrons and phonons in the solid state. In those systems, strong coupling makes the constituents lose their individual character and form dressed states, which represent a collective form of dynamics. As well as having fundamental importance, hybrid systems also have practical applications, notably in the emerging field of quantum information control. A promising approach is to combine long-lived atomic states with the accessible electrical degrees of freedom in superconducting cavities and quantum bits (qubits). Here we integrate circuit cavity quantum electrodynamics with phonons. Apart from coupling to a microwave cavity, our superconducting transmon qubit, consisting of tunnel junctions and a capacitor, interacts with a phonon mode in a micromechanical resonator, and thus acts like an atom coupled to two different cavities. We measure the phonon Stark shift, as well as the splitting of the qubit spectral line into motional sidebands, which feature transitions between the dressed electromechanical states. In the time domain, we observe coherent conversion of qubit excitation to phonons as sideband Rabi oscillations. This is a model system with potential for a quantum interface, which may allow for storage of quantum information in long-lived phonon states, coupling to optical photons or for investigations of strongly coupled quantum systems near the classical limit.

  10. Linewidth broadening of a quantum dot coupled to an off-resonant cavity

    CERN Document Server

    Majumdar, Arka; Kim, Erik; Englund, Dirk; Kim, Hyochul; Petroff, Pierre; Vuckovic, Jelena

    2010-01-01

    We study the coupling between a photonic crystal cavity and an off-resonant quantum dot under resonant excitation of the cavity or the quantum dot. Linewidths of the quantum dot and the cavity as a function of the excitation laser power are measured. We show that the linewidth of the quantum dot, measured by observing the cavity emission, is significantly broadened compared to the theoretical estimate. This indicates additional incoherent coupling between the quantum dot and the cavity.

  11. Nonradiating and radiating modes excited by quantum emitters in open epsilon-near-zero cavities.

    Science.gov (United States)

    Liberal, Iñigo; Engheta, Nader

    2016-10-01

    Controlling the emission and interaction properties of quantum emitters (QEs) embedded within an optical cavity is a key technique in engineering light-matter interactions at the nanoscale, as well as in the development of quantum information processing. State-of-the-art optical cavities are based on high quality factor photonic crystals and dielectric resonators. However, wealthier responses might be attainable with cavities carved in more exotic materials. We theoretically investigate the emission and interaction properties of QEs embedded in open epsilon-near-zero (ENZ) cavities. Using analytical methods and numerical simulations, we demonstrate that open ENZ cavities present the unique property of supporting nonradiating modes independently of the geometry of the external boundary of the cavity (shape, size, topology, etc.). Moreover, the possibility of switching between radiating and nonradiating modes enables a dynamic control of the emission by, and the interaction between, QEs. These phenomena provide unprecedented degrees of freedom in controlling and trapping fields within optical cavities, as well as in the design of cavity opto- and acoustomechanical systems.

  12. 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.

  13. Resonant cavity light-emitting diodes: modeling, design, and optimization

    Science.gov (United States)

    Dumitrescu, Mihail M.; Sipila, Pekko; Vilokkinen, Ville; Toikkanen, L.; Melanen, Petri; Saarinen, Mika J.; Orsila, Seppo; Savolainen, Pekka; Toivonen, Mika; Pessa, Markus

    2000-02-01

    Monolithic top emitting resonant cavity light-emitting diodes operating in the 650 and 880 nm ranges have been prepared using solid-source molecular beam epitaxy growth. Transfer matrix based modeling together with a self- consistent model have been sued to optimize the devices' performances. The design of the layer structure and doping profile was assisted by computer simulations that enabled many device improvements. Among the most significant ones intermediate-composition barrier-reduction layers were introduced in the DBR mirrors for improving the I-V characteristics and the cavity and mirrors were detuned aiming at maximum extraction efficiency. The fabricated devices showed line widths below 15 nm, CW light power output of 8 and 22.5 mW, and external quantum efficiencies of 3 percent and 14.1 percent in the 650 nm and 880 nm ranges, respectively - while the simulations indicate significant performance improvement possibilities.

  14. Epitaxy and Characteristics of Resonant Cavity LEDs at 650 nm

    Institute of Scientific and Technical Information of China (English)

    Kang Yuzhu; Li Jianjun; Ding Liang; Yang Zhen; Han Jun; Deng Jun; Zou Deshu; Shen Guangdi

    2009-01-01

    Resonant-cavity light-emitting diodes (RCLED) at 650 nm wavelength were grown by metal organic chemical vapor deposition. In order to improve the interface quality and reduce the device voltage, an AlGaInP material system has been chosen to grow the top DBRs. The emission properties of the RCLED were characterized by measuring PL and EL spectra. The average emission power of the device is 0.5 mW at 20 mA and 2.2 V, and its spectrum full width at half maximum is about 10 nm.

  15. Imprisonment dynamics of resonance radiation in gases

    Energy Technology Data Exchange (ETDEWEB)

    Kosarev, N I; Shaparev, N Y, E-mail: kosarev_nikolai@mail.ru [Institute of Computational Modeling, Siberian Branch of the Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation)

    2011-05-28

    Imprisonment of resonant radiation in gases on the basis of the numerical solution of the rate balance equation for the excited atoms and the transfer resonant radiation equation is investigated. Calculations of the escape factor for the slab, cylinder and sphere at Doppler and Lorentz forms of absorption and scattering profiles are executed. Calculation results of the escape factor for the cylinder and slab are compared with Holsten's asymptotical solutions. The numerical data for time dependence of a spectrum, the intensity of resonant radiation and the spatial distribution of the excited atomic concentration in a regime of afterglow are also considered.

  16. Silicon resonant cavity enhanced photodetector arrays for optical interconnects

    Science.gov (United States)

    Emsley, Matthew Kent

    High bandwidth short distance communications standards are being developed based on parallel optical interconnect fiber arrays to meet the needs of increasing data rates of inter-chip communication in modern computer architecture. To ensure that this standard becomes an attractive option for computer systems, low cost components must be implemented on both the transmitting and receiving end of the fibers. To meet this low cost requirement silicon based receiver circuits are the most viable option, however, manufacturing high speed, high efficiency silicon photodetectors presents a technical challenge. Resonant cavity enhanced photodetectors have been shown to provide the required bandwidth-efficiency product but have remained a challenge to reproduce through commercially available fabrication techniques. In this work, commercially reproducible silicon wafers with a high reflectance buried distributed Bragg reflector (DBR) have been designed and fabricated. The substrates consist of a two-period, 90% reflecting, DBR fabricated using a double silicon-on-insulator (SOI) process. Resonant-cavity-enhanced (RCE) Si photodetectors have been fabricated with 40% quantum efficiency at 860 nm, a FWHM of 25 ps, and a 3dB bandwidth in excess of 10 GHz. Si RCE 12 x 1 photodetector arrays have been fabricated and packaged with silicon based amplifiers to demonstrate the feasibility of a low cost monolithic silicon photoreceiver array.

  17. Radiation Damage In Reactor Cavity Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G [ORNL; Le Pape, Yann [ORNL; Naus, Dan J [ORNL; Remec, Igor [ORNL; Busby, Jeremy T [ORNL; Rosseel, Thomas M [ORNL; Wall, Dr. James Joseph [Electric Power Research Institute (EPRI)

    2015-01-01

    License renewal up to 60 years and the possibility of subsequent license renewal to 80 years has established a renewed focus on long-term aging of nuclear generating stations materials, and recently, on concrete. Large irreplaceable sections of most nuclear generating stations include concrete. The Expanded Materials Degradation Analysis (EMDA), jointly performed by the Department of Energy, the Nuclear Regulatory Commission and Industry, identified the urgent need to develop a consistent knowledge base on irradiation effects in concrete. Much of the historical mechanical performance data of irradiated concrete does not accurately reflect typical radiation conditions in NPPs or conditions out to 60 or 80 years of radiation exposure. To address these potential gaps in the knowledge base, The Electric Power Research Institute and Oak Ridge National Laboratory are working to disposition radiation damage as a degradation mechanism. This paper outlines the research program within this pathway including: (i) defining the upper bound of the neutron and gamma dose levels expected in the biological shield concrete for extended operation (80 years of operation and beyond), (ii) determining the effects of neutron and gamma irradiation as well as extended time at temperature on concrete, (iii) evaluating opportunities to irradiate prototypical concrete under accelerated neutron and gamma dose levels to establish a conservative bound and share data obtained from different flux, temperature, and fluence levels, (iv) evaluating opportunities to harvest and test irradiated concrete from international NPPs, (v) developing cooperative test programs to improve confidence in the results from the various concretes and research reactors, (vi) furthering the understanding of the effects of radiation on concrete (see companion paper) and (vii) establishing an international collaborative research and information exchange effort to leverage capabilities and knowledge.

  18. Observation of the stimulated coherent diffraction radiation in an open resonator at LUCX facility

    Energy Technology Data Exchange (ETDEWEB)

    Aryshev, A., E-mail: alar@post.kek.jp [KEK: High Energy Accelerator Research Organization,1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Araki, S.; Fukuda, M. [KEK: High Energy Accelerator Research Organization,1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Karataev, P. [John Adams Institute at Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom); Konkov, A.; Naumenko, G.; Potylitsyn, A. [Tomsk Polytechnic University, Institute of Physics and Technology, Lenin ave. 30, Tomsk 634050 (Russian Federation); Sakaue, K. [Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Sukhikh, L. [Tomsk Polytechnic University, Institute of Physics and Technology, Lenin ave. 30, Tomsk 634050 (Russian Federation); Terunuma, N. [KEK: High Energy Accelerator Research Organization,1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Verigin, D. [Tomsk Polytechnic University, Institute of Physics and Technology, Lenin ave. 30, Tomsk 634050 (Russian Federation); Urakawa, J. [KEK: High Energy Accelerator Research Organization,1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2014-11-01

    We present an initial test of a new type of a pre-bunched beam pumped free electron maser based on Stimulated Coherent Diffraction Radiation (SCDR) generated in an open resonator. A fast Schottky Barrier Diode (time response <1ns) has enabled us to investigate the properties of the radiation stored in the cavity as well as the intrinsic properties of the cavity itself. We observed a turn-by-turn SCDR generated by a multibunch beam. When the cavity length was exactly a half of the bunch spacing a clear resonance was observed. Moreover, turn-by-turn measurements revealed the cavity quality factor of 72.88, which was rather high for an open resonator in the wavelength range of 3–5 mm. An exponential growth of the photon intensity as a function of the number of bunches was also demonstrated.

  19. Radiation Characteristics of the Cavity Backed Antenna in Conducting Cone

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A technique using finite element and boundary integral method (FE-BI) and reciprocity theorem is presented to analyze the radiation characteristics of cavity backed antenna mounted on a conducting cone. The electric fields inside the cavity and on the aperture are obtained using finite element and boundary integral method. The far-field characteristic of the antenna is computed using reciprocity theorem. The paper begins with a general description of the method. An application of this method is given and the numerical result is compared with the experimental result.

  20. A Lamb wave source based on the resonant cavity of phononic-crystal plates.

    Science.gov (United States)

    Sun, Jia-Hong; Wu, Tsung-Tsong

    2009-01-01

    In this paper, we propose a Lamb wave source that is based on the resonant cavity of a phononic-crystal plate. The phononic-crystal plate is composed of tungsten cylinders that form square lattices in a silicon plate, and the resonant cavity is created by arranging defects inside the periodic structure. The dispersion, transmission, and displacement of Lamb waves are analyzed by the finite-difference time-domain (FDTD) method. The eigenmodes inside the cavities of the phononic-crystal plate are identified as resonant modes. The fundamental and higher order resonant modes, which vary with the length of cavities, are calculated. By exciting the specific resonant mode in an asymmetric cavity, the 232.40 MHz flexural Lamb wave has a magnified amplitude of 78 times larger than the normal one. Thus, the cavity on the tungsten/silicon phononic-crystal plate may serve as a source element in a microscale acoustic wave device.

  1. Multipacting Analysis for the Half-Wave Spoke Resonator Crab Cavity for LHC

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Lixin; Li, Zenghai; /SLAC

    2011-06-23

    A compact 400-MHz half-wave spoke resonator (HWSR) superconducting crab cavity is being developed for the LHC upgrade. The cavity shape and the LOM/HOM couplers for such a design have been optimized to meet the space and beam dynamics requirements, and satisfactory RF parameters have been obtained. As it is known that multipacting is an issue of concern in a superconducting cavity which may limit the achievable gradient. Thus it is important in the cavity RF design to eliminate the potential MP conditions to save time and cost of cavity development. In this paper, we present the multipacting analysis for the HWSR crab cavity using the Track3P code developed at SLAC, and to discuss means to mitigate potential multipacting barriers. Track3P was used to analyze potential MP in the cavity and the LOM, HOM and FPC couplers. No resonances were found in the LOM couplers and the coaxial beam pipe. Resonant trajectories were identified on various locations in cavity, HOM and FPC couplers. Most of the resonances are not at the peak SEY of Nb. Run-away resonances were identified in broader areas on the cavity end plate and in the HOM coupler. The enhancement counter for run-away resonances does not show significant MP. HOM coupler geometry will be optimized to minimize the high SEY resonance.

  2. Radiation by cavity-backed antennas on a circular cylinder

    Science.gov (United States)

    Kempel, Leo C.; Volakis, John L.; Sliva, Randy

    1994-01-01

    Conformal antenna arrays are popular antennas for aircraft, spacecraft and land vehicle platforms due to their inherent low weight, cost and drag properties. However, to date there has been a dearth of rigorous analytical or numerical solutions to aid the designer. In fact, it has been common practice to use limited measurements and planar approximations in designing such non-planar antennas. The finite element-boundary integral method is extended to radiation by cavity-backed structures in an infinite, metallic cylinder. The formulation is used to investigate the effect of cavity size on the radiation pattern for typical circumferentially and axially polarized patch antennas. Curvature effect on the gain, pattern shape, and input impedance is also studied. Finally, the accuracy of the FE-BI approach for a microstrip patch array is demonstrated.

  3. New resonant cavity-enhanced absorber structures for mid-infrared detector application

    CERN Document Server

    Zohar, Moshe; Faraone, Lorenzo; Hava, Shlomo

    2012-01-01

    A new dielectric Fabry-Perot cavity was designed for a resonant enhancing optical absorption by a thin absorber layer embedded into the cavity. In this cavity, the front mirror is a subwavelength grating with $\\sim 100$% retroreflection. For a HgCdTe absorber in a matching cavity of the new type, the design is shown to meet the combined challenges of increasing the absorbing efficiency of the entire device up to $\\sim 100$% and reducing its size and overall complexity, compared to a conventional resonant cavity enhanced HgCdTe absorber, while maintaining a fairly good tolerance against the grating's fabrication errors.

  4. A Complex Frequency Method for A Loaded Resonant Cavity of Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    LIANGChanghong; LILong; SUTao; FANShengcai

    2004-01-01

    A complex frequency method for analyzing a loaded resonant cavity of transmission lines is presented in this paper. A sub-resonance system theory is used to treat the various loaded transmission lines cavity more effectively. Some practice examples are given to illustrate the application and validity of the proposed approach in this paper.

  5. Efficient second harmonic generation of a diode-laser-pumped CW Nd:YAG laser using monolithic MgO:LiNbO3 external resonant cavities

    Science.gov (United States)

    Kozlovsky, William J.; Nabors, C. D.; Byer, Robert L.

    1988-01-01

    56-percent efficient external-cavity-resonant second-harmonic generation of a diode-laser pumped, CW single-axial-mode Nd:YAG laser is reported. A theory of external doubling with a resonant fundamental is presented and compared to experimental results for three monolithic cavities of nonlinear MgO:LiNbO3. The best conversion efficiency was obtained with a 12.5-mm-long monolithic ring cavity doubler, which produced 29.7 mW of CW, single-axial model 532-nm radiation from an input of 52.5 mW.

  6. Simulation of plasma filled hemispherical cavity as dielectric resonator antenna

    Science.gov (United States)

    Trenchev, G.; Kissóvski, Zh

    2016-10-01

    Plasma antennas are becoming an increasingly interesting research topic because of their uncommon characteristics. They are highly configurable, can be turned on and off rapidly, and exhibit lower thermal noise compared to metal antennas. In recent years, research has been conducted on cylindrical plasma columns sustained by DC, RF or microwave field, and their application as leaky wave antennas or as regular monopole antennas. Dielectric resonator antennas (DRA) with high dielectric permittivity are known for their small size and excellent operating characteristics for modern mobile communications (WiMAX, LTE). Hemispherical dielectric resonator antennas are characterized by simple shape, high radiation efficiency and wide bandwidth. Hemispherical DRA with a low density weakly ionized plasma as dielectric material will combine the positive features of plasma and dielectric antennas, and is particularly interesting, as antennas of this type have not been studied yet. The hemispherical plasma antenna is simulated with Ansoft HFSS in the microwave S-band. Obtained radiation pattern and bandwidth show the advantages of hemispherical plasma antennas for future communication technology.

  7. Radiation treatment for newly diagnosed esophageal cancer with prior radiation to the thoracic cavity

    Energy Technology Data Exchange (ETDEWEB)

    Sponseller, Patricia, E-mail: sponselp@uw.edu [University of Wisconsin at La Crosse, La Crosse, WI (United States); Lenards, Nishele [Department of Radiation Oncology, University of Washington, Seattle, WA (United States); Kusano, Aaron; Patel, Shilpen [University of Wisconsin at La Crosse, La Crosse, WI (United States)

    2014-10-01

    The purpose of this report is to communicate the use of single-positron emission computed tomography scan in planning radiation treatments for patients with a history of radiation to the thoracic cavity. A patient presented with obstructive esophageal cancer, having previously received chemotherapy and radiation therapy to the mediastinum for non-Hodgkin lymphoma 11 years earlier. Owing to a number of comorbidities, the patient was not a surgical candidate and was referred to the University of Washington Medical Center for radiation therapy. Prior dose to the spinal cord and lung were taken into account before designing the radiation treatment plan.

  8. A quantum description of radiation damping and the free induction signal in magnetic resonance.

    Science.gov (United States)

    Tropp, James

    2013-07-07

    We apply the methods of cavity quantum electrodynamics (CQED), to obtain a microscopic and fully quantum-mechanical picture of radiation damping in magnetic resonance, and the nascent formation of the free induction signal. Numerical solution of the Tavis-Cummings model - i.e., multiple spins 1∕2 coupled to a lossless single-mode cavity - shows in fine detail the transfer of Zeeman energy, via spin coherence, to excite the cavity - represented here by a quantized LC resonator. The case of a single spin is also solved analytically. Although the motion of the Bloch vector is non-classical, we nonetheless show that the quantum mechanical Rabi nutation frequency (as enhanced by cavity coupling and stimulated emission) gives realistic estimates of macroscopic signal strength and the radiation damping constant in nuclear magnetic resonance. We also show how to introduce dissipation: cavity losses by means of a master equation, and relaxation by the phenomenological method of Bloch. The failure to obtain the full Bloch equations (unless semi-classical conditions are imposed on the cavity) is discussed in light of similar issues arising in CQED (and in earlier work in magnetic resonance as well), as are certain problems relative to quantization of the electromagnetic near-field.

  9. Fano resonances control and slow light with Bose-Einstein Condensate in a cavity setup

    CERN Document Server

    Akram, M Javed; Khan, M Miskeen; Saif, Farhan

    2015-01-01

    We theoretically investigate the probe field transmission in an optomechanical cavity setup with Bose-Einstein Condensate (BEC), where the standing wave that forms in the cavity results in an one-dimensional optical lattice potential. We report that in the presence of atom-atom interactions, the coupling of the cavity field with condensate (Bogoliubov mode), the cavity field fluctuations and the condensate fluctuations leads to the emergence of the tunable Fano resonances in the probe absorption spectrum. Within the experimental reach, based on analytical and numerical simulations, we find that the optomechanical system with BEC provides great flexibility to tune the Fano resonances, as the width of the resonance is controllable by the coupling field and additionally, with the atom-atom interaction. Moreover, Fano resonances are analyzed for the fluctuations of the cavity field and the fluctuations of the condensate with finite atomic two-body interaction, which shows an excellent compatibility with the origi...

  10. Silicon resonant-cavity-enhanced photodetector arrays for optical interconnects

    Science.gov (United States)

    Emsley, Matthew K.; Dosunmu, Olufemi I.; Muller, Paul; Unlu, M. Selim; Leblebici, Yusuf

    2003-08-01

    High bandwidth short distance communications standards are being developed based on parallel optical interconnect fiber arrays to meet the needs of increasing data rates of inter-chip communication in modern computer architecture. To ensure that this standard becomes an attractive option for computer systems, low cost components must be implemented on both the transmitting and receiving end of the fibers. To meet this low cost requirement silicon based receiver circuits are the most viable option, however, manufacturing high speed, high efficiency silicon photodetectors presents a technical challenge. Resonant cavity enhanced (RCE) Si photodetectors have been shown to provide the required bandwidth-efficiency product and we have recently developed a method to reproduce them through commercially available fabrication techniques. In this work, commercially reproducible silicon wafers with a 90% reflectance buried distributed Bragg reflector (DBR) are used to create Si-RCE photodetector arrays for optical interconnects. The Si-RCE photodetectors have 40% quantum efficiency at 860 nm, a FWHM of 25 ps, and a 3dB bandwidth in excess of 10 GHz. We also demonstrate Si-RCE 12×1 photodetector arrays that have been fabricated and packaged with silicon based amplifiers to demonstrate the feasibility of a low cost monolithic silicon photoreceiver array.

  11. Cavity Quantum Electrodynamics in a wide aperture spherical resonator. Part I Cavity-induced damping and level shifts

    CERN Document Server

    Daul, J M; Daul, Jean-Marc; Grangier, Philippe

    2003-01-01

    We calculate explicitly the space dependence of the radiative relaxation rates and associated level shifts for a dipole placed in the vicinity of the center of a spherical cavity with a large numerical aperture and a relatively low finesse. In particular, we give simple and useful analytic formulas for these quantities, that can be used with arbitrary mirrors transmissions. The vacuum field in the vicinity of the center of the cavity is actually equivalent to the one obtained in a microcavity, and this scheme allows one to predict significant cavity QED effects

  12. Preparation of W state in resonant bimodal cavity quantum electrodynamics

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A scheme is proposed for generating entangled W states with four cavity modes. In this scheme, we send a Ⅴ-type three-level atom through two identical two-mode cavities in succession. After the atom exits from the second cavity,the four cavity modes are prepared in the W state. On the other hand we can obtain three-atom W states by sending three Ⅴ-type three-level atoms through a two-mode cavity in turn. The present scheme does not require conditional measurement, and it is easily generalized to preparing 2n-mode W states and n-atom W states.

  13. 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.

  14. Off-resonance coupling between a cavity mode and an ensemble of driven spins

    Science.gov (United States)

    Wang, Hui; Masis, Sergei; Levi, Roei; Shtempluk, Oleg; Buks, Eyal

    2017-05-01

    We study the interaction between a superconducting cavity and a spin ensemble. The response of a cavity mode is monitored while simultaneously the spins are driven at a frequency close to their Larmor frequency, which is tuned to a value much higher than the cavity resonance. We experimentally find that the effective damping rate of the cavity mode is shifted by the driven spins. The measured shift in the damping rate is attributed to the retarded response of the cavity mode to the driven spins. The experimental results are compared with theoretical predictions and fair agreement is found.

  15. Discovery of higher order modes in a cylindrical reentrant-ring cavity resonator

    CERN Document Server

    Fan, Y; Carvalho, N C; Floch, J-M Le; Shan, Q; Tobar, M E

    2013-01-01

    Rigorous analysis of the properties of resonant modes in a reentrant cavity structure comprising of a post and ring is undertaken and verified experimentally. In particular for the first time we show the existence of higher order reentrant cavity modes in such a structure. Results show this cavity has a better displacement sensitivity compared to the common fundamental mode in a reentrant cylindrical cavity with just a single post. Thus, this type of cavity has the potential to operate as a highly sensitive transducer for a variety of precision measurement applications.

  16. Radiation Bandwidth Improvement of Electromagnetic Band Gap Cavity Antenna

    Science.gov (United States)

    Chaabane, Abdelhalim; Djahli, Farid; Attia, Hussein; Denidni, Tayeb. A.

    2017-09-01

    In this paper, an electromagnetic band gap cavity antenna with improved radiation and impedance bandwidths is presented. The proposed antenna is constructed by placing a triple-layer heterogeneous printed-unprinted partially reflective surface (PRS) above a primary aperture-coupled patch antenna. The PRS unit-cell provides a positive gradient reflection phase behavior over the desired frequency range. A prototype antenna is fabricated and measured that highlighted its ability to achieve 3-dB gain bandwidth of about 35.9 %, from 7.93 GHz to 11.4 GHz, with a peak gain of 14.25 dBi at 8.5 GHz. In addition, the impedance bandwidth is 40.32 %, from 7.9 GHz to 11.89 GHz. Thus, the designed antenna outperforms many other competitors for improving the radiation bandwidth of planar antennas with the same presented concept.

  17. Sensitive temperature measurements based on Lorentzian and Fano resonance lineshapes of a silicon photonic crystal cavity

    Science.gov (United States)

    Zhao, Chenyang; Fang, Liang; Yuan, Qinchen; Gan, Xuetao; Zhao, Jianlin

    2016-10-01

    We report a high-performance photonic temperature sensor by exploiting a silicon photonic crystal (PC) cavity. Since the PC cavity's spectra are very sensitive to the refractive index change, we observe remarkable variations of its resonant wavelength and output power under varying temperature levels. In a PC cavity with Lorentzian resonance lineshape, the sensor exhibits a linear spectrum-sensitivity of 70 pm/°, and the power-variation presents a high sensitivity as 1.28 dB/°. In addition, the Fano resonance lineshape generated by the PC cavity has also been employed to measure the temperature, which shows improved power sensitivity as 2.94 dB/ °. The demonstrated PC cavity-based sensor offers great potentials for low-cost, high sensitivity homogeneous sensing in chip-integrated devices.

  18. Optical control of resonant light transmission for an atom-cavity system

    CERN Document Server

    Sharma, Arijit; Sawant, Rahul V; Sheikholeslami, G; Budker, D; Rangwala, S A

    2015-01-01

    We demonstrate the manipulation of transmitted light through an optical Fabry-Perot cavity, built around a spectroscopy cell containing enriched rubidium vapor. Light resonant with the $^{87}$Rb D$_{2}$ ($F=2/F=1$) $\\leftrightarrow F'$ manifold, is controlled by transverse intersection of the cavity mode by another resonant light beam. The cavity transmission can be suppressed or enhanced depending on the coupling of atomic states due to the intersecting beams. The extreme manifestation of cavity mode control is the precipitious destruction (negative logic switching) or buildup (positive logic switching) of the transmitted light intensity, on intersection of the transverse control beam with the cavity mode. Both the steady state and transient response are experimentally investigated. The mechanism behind the change in cavity transmission is discussed in brief.

  19. Detecting body cavity bombs with nuclear quadrupole resonance

    Science.gov (United States)

    Collins, Michael London

    Nuclear Quadrupole Resonance (NQR) is a technology with great potential for detecting hidden explosives. Past NQR research has studied the detection of land mines and bombs concealed within luggage and packages. This thesis focuses on an NQR application that has received less attention and little or no publicly available research: detecting body cavity bombs (BCBs). BCBs include explosives that have been ingested, inserted into orifices, or surgically implanted. BCBs present a threat to aviation and secure facilities. They are extremely difficult to detect with the technology currently employed at security checkpoints. To evaluate whether or not NQR can be used to detect BCBs, a computational model is developed to assess how the dielectric properties of biological tissue affect the radio frequency magnetic field employed in NQR (0.5-5MHz). The relative permittivity of some biological tissue is very high (over 1,000 at 1MHz), making it conceivable that there is a significant effect on the electromagnetic field. To study this effect, the low-frequency approximation known as the Darwin model is employed. First, the electromagnetic field of a coil is calculated in free space. Second, a dielectric object or set of objects is introduced, and the free-space electric field is modified to accommodate the dielectric object ensuring that the relevant boundary conditions are obeyed. Finally, the magnetic field associated with the corrected electric field is calculated. This corrected magnetic field is evaluated with an NQR simulation to estimate the impact of dielectric tissue on NQR measurements. The effect of dielectric tissue is shown to be small, thus obviating a potential barrier to BCB detection. The NQR model presented may assist those designing excitation and detection coils for NQR. Some general coil design considerations and strategies are discussed.

  20. Evolution of Gaussian beams and pulsed laser action in laser with unstable resonant cavities

    Energy Technology Data Exchange (ETDEWEB)

    Isaev, A.A.; Kazarian, M.A.; Petrash, G.G.; Rautian, S.G.; Shalagin, A.M.

    1975-06-01

    A recurrent formula is derived which describes the passage of a Gaussian beam through an unstable resonant cavity and through a periodic optical system. The changes in the position and in the beam neck at the mirror within an arbitrary unstable cavity are analyzed as a function of the beam's initial parameters and the number of passages in the cavity. The evolution of nonaxial Gaussian beams is studied, and a generalization of the Lagrange-Helmholtz theorem is proposed.

  1. Experimental studies on perturbed acoustic resonant spectroscopy by a small rock sample in a cylindrical cavity

    Institute of Scientific and Technical Information of China (English)

    CHEN Dehua; WANG Xiuming; CONG Jiansheng; XU Delong; SONG Yanjie; MA Shuilong

    2006-01-01

    A measurement system for acoustic resonant spectroscopy (ARS) is established,and the effects of resonant cavity geometry,inner perturbation samples and environmental temperature on the ARS are investigated.The ARSs of the small samples with various sizes and acoustic properties are measured.The results show that at the normal pressure,the resonant frequency decreases gradually with the increase of liquid temperature in the cylindrical cavity,while the resonant amplitude increases.At certain pressure and temperature,both the resonant frequency and the amplitude decrease greatly when there exist air bubbles inside the cavity fluid.The ARS is apparently affected by the sample porosity and the sample location in the resonant cavity.At the middle of the cavity,the resonant frequencies reach their maximum values for all of the measurement samples.The resonant frequencies of the porous rock samples are smaller than those of the compacted samples if other acoustic parameters are the same.As the sample is moved from the top to the middle of the cavity along its axis,the resonant amplitude increases gradually for the compacted rocks while decreases for the unconsolidated rocks.Furthermore,the resonant amplitude increases firstly and then decreases if the porosity of the rock sample is relatively small.In addition,through the comparisons between the experimental and theoretical results,it is found that the effects of the acoustic parameters and sizes of the samples and the size of the cylindrical cavity on the laboratory results agree well with the theoretical ones qualitatively.These results may provide basic reference for the experiment study of rock acoustic properties in a low frequency using ARS.

  2. Spectrally and temporally resolved resonance shifts of a photonic crystal cavity switch

    DEFF Research Database (Denmark)

    Hansen, Per Lunnemann; Yu, Yi; Mørk, Jesper

    2016-01-01

    We present experimental results of temporally and spectrally resolved transmission measurements of a photonic crystal cavity using two-color pump-probe technique. With a gated spectral measurement, we measure the resonance shift's dependence on pump power.......We present experimental results of temporally and spectrally resolved transmission measurements of a photonic crystal cavity using two-color pump-probe technique. With a gated spectral measurement, we measure the resonance shift's dependence on pump power....

  3. Spectrally and temporally resolved resonance shifts of a photonic crystal cavity switch

    DEFF Research Database (Denmark)

    Hansen, Per Lunnemann; Yu, Yi; Mørk, Jesper

    2016-01-01

    We present experimental results of temporally and spectrally resolved transmission measurements of a photonic crystal cavity using two-color pump-probe technique. With a gated spectral measurement, we measure the resonance shift's dependence on pump power.......We present experimental results of temporally and spectrally resolved transmission measurements of a photonic crystal cavity using two-color pump-probe technique. With a gated spectral measurement, we measure the resonance shift's dependence on pump power....

  4. Design of plasmonic photonic crystal resonant cavities for polarization sensitive infrared photodetectors

    Science.gov (United States)

    Rosenberg, Jessie; Shenoi, Rajeev V.; Krishna, Sanjay; Painter, Oskar

    2010-02-01

    We design a polarization-sensitive resonator for use in midinfrared photodetectors, utilizing a photonic crystal cavity and a single or double-metal plasmonic waveguide to achieve enhanced detector efficiency due to superior optical confinement within the active region. As the cavity is highly frequency and polarization-sensitive, this resonator structure could be used in chip-based infrared spectrometers and cameras that can distinguish among different materials and temperatures to a high degree of precision.

  5. Resonant cavities in metallic single-wall nanotubes: Green's function calculations

    Science.gov (United States)

    Jódar, Esther; Pérez-Garrido, Antonio; Díaz-Sánchez, Anastasio

    2006-05-01

    We study the electronic transport of a metallic single-wall carbon nanotube sandwiched between two equal metallic single-wall nanotubes of different radii. We calculate the transmission function and the density of states using the Green’s function method. This cavity behaves as a resonant box with quasibound states producing resonances and antiresonances in transmission. This behavior is a consequence of the different band structures for nanotubes forming the cavity.

  6. 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.

  7. Recent Approaches for Broadening the Spectral Bandwidth in Resonant Cavity Optoelectronic Devices

    Directory of Open Access Journals (Sweden)

    Gun Wu Ju

    2015-01-01

    Full Text Available Resonant cavity optoelectronic devices, such as vertical cavity surface emitting lasers (VCSELs, resonant cavity enhanced photodetectors (RCEPDs, and electroabsorption modulators (EAMs, show improved performance over their predecessors by placing the active device structure inside a resonant cavity. The effect of the optical cavity, which allows wavelength selectivity and enhancement of the optical field due to resonance, allows the devices to be made thinner and therefore faster, while simultaneously increasing the quantum efficiency at the resonant wavelengths. However, the narrow spectral bandwidth significantly reduces operating tolerances, which leads to severe problems in applications such as optical communication, imaging, and biosensing. Recently, in order to overcome such drawbacks and/or to accomplish multiple functionalities, several approaches for broadening the spectral bandwidth in resonant cavity optoelectronic devices have been extensively studied. This paper reviews the recent progress in techniques for wide spectral bandwidth that include a coupled microcavity, asymmetric tandem quantum wells, and high index contrast distributed Bragg-reflectors. This review will describe design guidelines for specific devices together with experimental considerations in practical applications.

  8. High-precision spectral tuning of micro and nanophotonic cavities by resonantly enhanced photoelectrochemical etching

    CERN Document Server

    Gil-Santos, Eduardo; Lemaitre, Aristide; Gomez, Carmen; Ducci, Sara; Leo, Giuseppe; Favero, Ivan

    2015-01-01

    We present a simple method to tune optical micro- and nanocavities with picometer precision in the resonant wavelength, corresponding to an effective sub atomic monolayer control of the cavity dimension. This is obtained through resonant photo-electrochemical etching, with in-situ monitoring of the optical spectrum. We employ this technique to spectrally align an ensemble of resonant cavities in a permanent manner, overcoming the dimension variability resulting from current nanofabrication techniques. In a device containing several resonators, each is individually addressed and tuned, with no optical quality factor degradation. The technique is general and opens the way to multiple applications, such as the straightforward fabrication of networks of identical coupled resonators, or the tuning of chip-based cavities to external references.

  9. 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...... 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...

  10. Implementation of n-qubit Deutsch-Jozsa algorithm using resonant interaction in cavity QED

    Institute of Scientific and Technical Information of China (English)

    Wang Hong-Fu; Zhang Shou

    2008-01-01

    We propose a scheme to implement the n-qubit Deutsch-Jozsa algorithm based on resonant interaction between the atoms and a single-mode cavity. In the scheme, the resonant transitions between two ground states and one excited state of an atom are changed alternately by adjusting the cavity frequency appropriately, and the operations required to complete the algorithm can be significantly simplified following the increment of the number of qubits. The implementation of the scheme in experiment would show the full power of quantum algorithm and would be significative and important for more complicated quantum algorithm in cavity quantum electrodynamics.

  11. Approximate Toffoli Gate Originated from a Single Resonant Interaction of Cavity Dissipation and Atomic Spontaneous Emission

    Institute of Scientific and Technical Information of China (English)

    GU Xiao-Yan; CHEN Chang-Yong; SUN Jian-Qiang

    2008-01-01

    We propose a potentially practical scheme to implement an approximate three-qubit Toffoli gate by a single resonant interaction in dissipative cavity QED in which the cavity mode decay and atomic spontaneous emission are considered. The scheme does not require two-qubit controlled-NOT gates but uses a three-qubit phase gate and two Hadamard gates, where the approximate phase gate can be implemented by only a single dissipative resonant interaction of atoms with the cavity mode. Discussions are made for the advantages and the experimental feasibility of our scheme.

  12. Mode-locked pulse oscillation of a self-resonating enhancement optical cavity

    CERN Document Server

    Hosaka, Yuji; Kosuge, Atsushi; Omori, Tsunehiko; Sakaue, Kazuyuki; Takahashi, Tohru; Uesugi, Yuuki; Urakawa, Junji; Washio, Masakazu

    2016-01-01

    A power enhancement optical cavity is a compelling means of realizing a pulsed laser with a high peak power and a high repetition frequency, which is not feasible by using a simple amplifier scheme. However, a precise feedback system is necessary for maintaining the narrow resonance condition of the optical cavity, and has become a major technical issue in developing such cavities. We developed a new approach that does not require any active feedback system, by placing the cavity in the outer loop of a laser amplifier. We report on the first demonstration of a mode-locked pulse oscillation using the new system.

  13. Computation of high frequency fields in resonant cavities based on perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Brackebusch, Korinna; Glock, Hans-Walter; Rienen, Ursula van [Universitaet Rostock (Germany). Institut fuer Allgemeine Elektrotechnik

    2012-07-01

    The eigenmodes of an accelerator cavity are essential for the determination of its performance characteristics, comprising resonant frequencies and field distributions inside the cavity. Apart from the material properties the eigenmodes depend on the cavity geometry. Due to manufacturing tolerances and operational demands deviations of the actual cavity shape from the desired one are inevitable. Any geometry perturbation results in a shift of the resonant frequencies and modified field distributions. Slater's theorem offers an efficient way to compute the changed resonant frequencies, however, not the changed fields. In this work, we will analyse a generalisation of Slater's theorem proposed in literature. The method enables the computation of the resonant frequencies and the field distributions of a slightly perturbed cavity by using a set of eigenmodes of the unperturbed cavity. We evaluate the practicability of the method by applying it to cavity geometries for which the eigenmodes are analytically known, ascertain the effort of reasonable computation results and describe the limitations of the method.

  14. Design of an efficient terahertz source using triply resonant nonlinear photonic crystal cavities.

    Science.gov (United States)

    Burgess, Ian B; Zhang, Yinan; McCutcheon, Murray W; Rodriguez, Alejandro W; Bravo-Abad, Jorge; Johnson, Steven G; Loncar, Marko

    2009-10-26

    We propose a scheme for efficient cavity-enhanced nonlinear THz generation via difference-frequency generation (DFG) processes using a triply resonant system based on photonic crystal cavities. We show that high nonlinear overlap can be achieved by coupling a THz cavity to a doubly-resonant, dual-polarization near-infrared (e.g. telecom band) photonic-crystal nanobeam cavity, allowing the mixing of three mutually orthogonal fundamental cavity modes through a chi((2)) nonlinearity. We demonstrate through coupled-mode theory that complete depletion of the pump frequency - i.e., quantum-limited conversion - is possible. We show that the output power at the point of optimal total conversion efficiency is adjustable by varying the mode quality (Q) factors.

  15. Strongly Enhanced and Directionally Tunable Second-Harmonic Radiation by a Plasmonic Particle-in-Cavity Nanoantenna

    CERN Document Server

    Xiong, Xiaoyan Y Z; Sha, Wei E I; Lo, Yat Hei; Chew, Weng Cho

    2016-01-01

    Second-harmonic (SH) generation is tremendously important for nonlinear sensing, microscopy and communication system. One of the great challenges of current designs is to enhance the SH signal and simultaneously tune its radiation direction with a high directivity. In contrast to the linear plasmonic scattering dominated by a bulk dipolar mode, a complex surface-induced multipolar interaction sets a fundamental limit to control the SH radiation from metallic nanostructures. In this work, we harness plasmonic hybridization mechanism together with a special selection rule governing the SH radiation to achieve the high-intensity and tunable-direction emission by a metallic particle-in-cavity nanoantenna (PIC-NA). The nanoantenna is modelled with a first-principle, self-consistent boundary element method, which considers the depletion of pump waves. The giant SH enhancement arises from a hybridized gap plasmon resonance between the small particle and the large cavity that functions as a concentrator and reflector...

  16. Optical bistability enabled control of resonant light transmission for an atom-cavity system

    CERN Document Server

    Sawant, Rahul

    2015-01-01

    The control of light transmission through a Fabry-Perot cavity containing atoms is theoretically investigated, when the cavity mode beam and an intersecting control beam are both close to specific atomic resonances. A four-level atomic system is considered and its interaction with the cavity mode is studied by solving for the time dependent cavity field and atomic state populations. The conditions for optical bistability of the atom-cavity system are obtained in steady state limit. For an ensemble of atoms in the cavity mode, the response of the intra-cavity light intensity to the intersecting resonant beam is understood for stationary atoms (closed system) and non-static atoms (open system). The open system is modelled by adjusting the atomic state populations to represent the exchange of atoms in the cavity mode, with the thermal environment. The solutions to the model are used to qualitatively explain the observed steady state and transient behaviour of the light in the cavity mode, in Sharma et. al. [1]. ...

  17. Two-dimensional imaging of optical emission in a multicusp-ECR microwave resonant cavity

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, C.B.; Brake, M.L. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering

    1996-02-01

    Optical emission of the electron-cyclotron resonant (ECR) region of a multicusp microwave resonant cavity plasma source has been imaged onto a two-dimensional charge-coupled device (CCD) camera. The technique provides a real-time diagnostic of the plasma emission around the ECR region within a wavelength region defined by low-bandpass filters.

  18. 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.

  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. Gain enhanced Fano resonance in a coupled photonic crystal cavity-waveguide structure

    Science.gov (United States)

    Zhao, Yanhui; Qian, Chenjiang; Qiu, Kangsheng; Tang, Jing; Sun, Yue; Jin, Kuijuan; Xu, Xiulai

    2016-01-01

    Systems with coupled cavities and waveguides have been demonstrated as optical switches and optical sensors. To optimize the functionalities of these optical devices, Fano resonance with asymmetric and steep spectral line shape has been used. We theoretically propose a coupled photonic crystal cavity-waveguide structure to achieve Fano resonance by placing partially reflecting elements in waveguide. To enhance Fano resonance, optical gain material is introduced into the cavity. As the gain increases, the transmission line shape becomes steepened and the transmissivity can be six times enhanced, giving a large contrast by a small frequency shift. It is prospected that the gain enhanced Fano resonance is very useful for optical switches and optical sensors. PMID:27640809

  1. Tunable resonance cavity control in a near-field scanning microwave microscope

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Hyuk; Kim, Joo Young; Lee, Kre Jin [Sogang Univ., Seoul (Korea, Republic of); Kim, Jin Tae [KRISS, Daejon (Korea, Republic of); Cha, Deok Joon [Kunsan National Univ., Kunsan (Korea, Republic of); Lee, Yong San [Daejin Univ., Pochon (Korea, Republic of)

    2002-05-01

    We report a microwave surface imaging technique using a near-field scanning microwave microscope with a tunable resonance cavity. By tuning the resonance cavity, we could demonstrate improved sensitivity and spatial resolution of the near-field image of YBa{sub 2}Cu{sub 3}O{sub y} thin films on MgO substrates. By measuring the shift in the resonant frequency and the change in the quality factor, we obtained near-field scanning microwave images with a spatial resolution better than 4 {mu}m at an operating frequency of f=1-1.5 GHz. The principal of operation can be explained by using the perturbation theory of a coaxial resonant cavity, considering the radius of the probe tip and the sample-tip distance.

  2. Magnetic resonance acoustic radiation force imaging.

    Science.gov (United States)

    McDannold, Nathan; Maier, Stephan E

    2008-08-01

    Acoustic radiation force impulse imaging is an elastography method developed for ultrasound imaging that maps displacements produced by focused ultrasound pulses systematically applied to different locations. The resulting images are "stiffness weighted" and yield information about local mechanical tissue properties. Here, the feasibility of magnetic resonance acoustic radiation force imaging (MR-ARFI) was tested. Quasistatic MR elastography was used to measure focal displacements using a one-dimensional MRI pulse sequence. A 1.63 or 1.5 MHz transducer supplied ultrasound pulses which were triggered by the magnetic resonance imaging hardware to occur before a displacement-encoding gradient. Displacements in and around the focus were mapped in a tissue-mimicking phantom and in an ex vivo bovine kidney. They were readily observed and increased linearly with acoustic power in the phantom (R2=0.99). At higher acoustic power levels, the displacement substantially increased and was associated with irreversible changes in the phantom. At these levels, transverse displacement components could also be detected. Displacements in the kidney were also observed and increased after thermal ablation. While the measurements need validation, the authors have demonstrated the feasibility of detecting small displacements induced by low-power ultrasound pulses using an efficient magnetic resonance imaging pulse sequence that is compatible with tracking of a dynamically steered ultrasound focal spot, and that the displacement increases with acoustic power. MR-ARFI has potential for elastography or to guide ultrasound therapies that use low-power pulsed ultrasound exposures, such as drug delivery.

  3. Silicon reflectors for external cavity lasers based on ring resonators

    Science.gov (United States)

    Wang, Chao; Li, Xia; Jin, Hao; Yu, Hui; Yang, Jianyi; Jiang, Xiaoqing

    2017-01-01

    We propose and experimentally investigate types of silicon ring reflectors on Silicon-On-Insulator (SOI) platform. These reflectors are used for realizing the silicon hybrid external cavity lasers. A suspended edge coupler is used to connect the reflective semiconductor optical amplifier (RSOA) chip and the reflectors. The properties of the reflectors and the hybrid external cavity lasers with these reflectors are illustrated. The experimental results show that all of those reflectors have a high reflectivity and the highest reflectivity can up to be 95%. The lowest insertion loss can be as low as 0.4 dB. The output power of the hybrid external cavity lasers with these reflectors can reach mW magnitude and the highest output power is 6.1 mW. Over 30 dB side mode suppression ratio is obtained.

  4. Optical-bistability-enabled control of resonant light transmission for an atom-cavity system

    Science.gov (United States)

    Sawant, Rahul; Rangwala, S. A.

    2016-02-01

    The control of light transmission through a standing-wave Fabry-Pérot cavity containing atoms is theoretically and numerically investigated, when the cavity mode beam and an intersecting control beam are both close to specific atomic resonances. A four-level atomic system is considered and its interaction with the cavity mode is studied by solving for the cavity field and atomic state populations. The conditions for optical bistability of the atom-cavity system are obtained. The response of the intracavity intensity to an intersecting beam on atomic resonance is understood in the presence of stationary atoms (closed system) and nonstatic atoms (open system) in the cavity. The nonstatic system of atoms is modelled by adjusting the atomic state populations to represent the exchange of atoms in the cavity mode, which corresponds to a thermal environment where atoms are moving in and out of the cavity mode volume. The control behavior with three- and two-level atomic systems is also studied, and the rich physics arising out of these systems for closed and open atomic systems is discussed. The solutions to the models are used to interpret the steady-state and transient behavior observed by Sharma et al. [Phys. Rev. A 91, 043824 (2015)], 10.1103/PhysRevA.91.043824.

  5. Towards achieving strong coupling in three-dimensional-cavity with solid state spin resonance

    Science.gov (United States)

    Le Floch, J.-M.; Delhote, N.; Aubourg, M.; Madrangeas, V.; Cros, D.; Castelletto, S.; Tobar, M. E.

    2016-04-01

    We investigate the microwave magnetic field confinement in several microwave three-dimensional (3D)-cavities, using a 3D finite-element analysis to determine the best design and achieve a strong coupling between microwave resonant cavity photons and solid state spins. Specifically, we design cavities for achieving strong coupling of electromagnetic modes with an ensemble of nitrogen vacancy (NV) defects in diamond. We report here a novel and practical cavity design with a magnetic filling factor of up to 4 times (2 times higher collective coupling) than previously achieved using one-dimensional superconducting cavities with a small mode volume. In addition, we show that by using a double-split resonator cavity, it is possible to achieve up to 200 times better cooperative factor than the currently demonstrated with NV in diamond. These designs open up further opportunities for studying strong and ultra-strong coupling effects on spins in solids using alternative systems with a wider range of design parameters. The strong coupling of paramagnetic spin defects with a photonic cavity is used in quantum computer architecture, to interface electrons spins with photons, facilitating their read-out and processing of quantum information. To achieve this, the combination of collective coupling of spins and cavity mode is more feasible and offers a promising method. This is a relevant milestone to develop advanced quantum technology and to test fundamental physics principles.

  6. The cavity resonator design: stochastic optimization of the transmission line method

    Science.gov (United States)

    Jurečka, Stanislav; Müllerová, Jarmila; Dado, Milan

    2012-02-01

    Stable cavity resonators provide an ideal solution for high quality applications in telecommunications, laser sources, sensors, oscillators and filters, instrumentation and other large area of applications. For the determination of the electromagnetic field (EMF) properties in a cavity resonator several numerical methods are widely used. In our approach we used the transmission line modeling method (TLM). It is a wide-band time-domain numerical method suitable for solution of the electromagnetic field in a studied region. TLM method is based on the isomorphism between the theory of passive electrical network and the wave equation describing the properties of the EMF. TLM method offers two important advantages over the time-domain techniques such as the finite-difference time domain methods. The electric and magnetic field are resolved synchronously in time and space and TLM in implicitly stable method due to the mapping to electrical circuits. The EMF in the rectangular cavity is in our approach determined by the TLM method and the frequency spectrum is computed by the Fourier transform of the time signal. The theoretical model of the cavity EMF power spectral density function contains information about the geometrical configuration of the resonator. In our work we use the genetic algorithm for the determination of optimal dimensions of the cavity resonator expected for the proposed output resonant frequency. The stochastic modification of the theoretical model parameters is controlled by the genetic operators of mutation, crossover and selection, leading to overall improvement of the theoretical model estimation during the optimization process.

  7. Resonant diffraction of synchrotron radiation: New possibilities

    Science.gov (United States)

    Ovchinnikova, E. N.; Mukhamedzhanov, E. Kh.

    2016-09-01

    Resonant diffraction of synchrotron radiation (SR) is a modern method of studying the structure and properties of condensed matter that can be implemented on third-generation synchrotrons. This method allows one to investigate local properties of media (including magnetic and electronic ones) and observe thermal vibrations, defects, and orbital and charge orderings. A brief review of the advance provided by SR resonant diffraction is presented, and the capabilities of this method for analyzing phase transitions are considered in more detail by the example of potassium dihydrogen phosphate and rubidium dihydrogen phosphate crystals. It is shown that the investigation of the temperature dependence of forbidden reflections not only makes it possible to observe the transition from para- to ferroelectric phase, but also gives information about the proton distribution at hydrogen bonds.

  8. Radiation from structured-ring resonators

    CERN Document Server

    Maling, B; Craster, R V

    2016-01-01

    We investigate the scalar-wave resonances of systems composed of identical Neumann-type inclusions arranged periodically around a circular ring. Drawing on natural similarities with the undamped Rayleigh-Bloch waves supported by infinite linear arrays, we deduce asymptotically the exponentially small radiative damping in the limit where the ring radius is large relative to the periodicity. In our asymptotic approach, locally linear Rayleigh-Bloch waves that attenuate exponentially away from the ring are matched to a ring-scale WKB-type wave field. The latter provides a descriptive physical picture of how the mode energy is transferred via tunnelling to a circular evanescent-to-propagating transition region a finite distance away from the ring, from where radiative grazing rays emanate to the far field. Excluding the zeroth-order standing-wave modes, the position of the transition circle bifurcates with respect to clockwise and anti-clockwise contributions, resulting in striking spiral wavefronts.

  9. Solution of Cavity Resonance and Waveguide Scattering Problems Using the Eigenmode Projection Technique

    CERN Document Server

    Nasr, Mamdouh H; Eshrah, Islam A; Abuelfadl, Tamer M

    2016-01-01

    An eigenmode projection technique (EPT) is developed and employed to solve problems of electromagnetic resonance in closed cavities and scattering from discontinuities in guided-wave structures. The EPT invokes the eigenmodes of a canonical predefined cavity in the solution procedure and uses the expansion of these eigenmodes to solve Maxwell's equations, in conjunction with a convenient choice of port boundary conditions. For closed cavities, resonance frequencies of arbitrary-shaped cavities are accurately determined with a robust and efficient separation method of spurious modes. For waveguide scattering problems, the EPT is combined with the generalized scattering matrix approach to solve problems involving waveguide discontinuities with arbitrary dielectric profiles. Convergence studies show stable solutions for a relatively small number of expansion modes, and the proposed method shows great robustness over conventional solvers in analyzing electromagnetic problems with inhomogeneous materials.

  10. Teleportation of two-atom entangled state in resonant cavity quantum electrodynamics

    Institute of Scientific and Technical Information of China (English)

    Yang Zhen-Biao

    2007-01-01

    An alternative scheme is presented for teleportation of a two-atom entangled state in cavity quantum electrodynamics (QED). It is based on the resonant atom-cavity field interaction. In the scheme, only one cavity is involved, and the number of the atoms needed to be detected is decreased compared with the previous scheme. Since the resonant atom-cavity field interaction greatly reduces the interaction time, the decoherence effect can be effectively suppressed during the teleportation process. The experimental feasibility of the scheme is discussed. The scheme can easily be generalized to the teleportation of N-atom Greeninger-Horne-Zeilinger (GHZ) entangled states. The number of atoms needed to be detected does not increase as the number of the atoms in the GHZ state increases.

  11. Resonance suppression and electromagnetic shielding effectiveness improvement of an apertured rectangular cavity by using wall losses

    Institute of Scientific and Technical Information of China (English)

    Jiao Chong-Qing; Zhu Hong-Zhao

    2013-01-01

    The cavity-mode resonance effect could result in significant degradation of the shielding effectiveness (SE) of a shielding enclosure around its resonance frequencies.In this paper,the influence of coated wall loss on the suppression of the resonance effect is investigated.For this purpose,an equivalent circuit model is employed to analyze the SE of an apertured rectangular cavity coated with an inside layer of resistive material.The model is developed by extending Robinson's equivalent circuit model through incorporating the effect of the wall loss into both the propagation constant and the characteristic impedance of the waveguide.Calculation results show that the wall loss could lead to great improvement on the SE for frequencies near the resonance but almost no effect on the SE for frequencies far away from the resonance.

  12. Near-field coupling and resonant cavity modes in plasmonic nanorod metamaterials.

    Science.gov (United States)

    Song, Haojie; Zhang, Junxi; Fei, Guangtao; Wang, Junfeng; Jiang, Kang; Wang, Pei; Lu, Yonghua; Iorsh, Ivan; Xu, Wei; Jia, Junhui; Zhang, Lide; Kivshar, Yuri S; Zhang, Lin

    2016-10-14

    Plasmonic resonant cavities are capable of confining light at the nanoscale, resulting in both enhanced local electromagnetic fields and lower mode volumes. However, conventional plasmonic resonant cavities possess large Ohmic losses at metal-dielectric interfaces. Plasmonic near-field coupling plays a key role in a design of photonic components based on the resonant cavities because of the possibility to reduce losses. Here, we study the plasmonic near-field coupling in the silver nanorod metamaterials treated as resonant nanostructured optical cavities. Reflectance measurements reveal the existence of multiple resonance modes of the nanorod metamaterials, which is consistent with our theoretical analysis. Furthermore, our numerical simulations show that the electric field at the longitudinal resonances forms standing waves in the nanocavities due to the near-field coupling between the adjacent nanorods, and a new hybrid mode emerges due to a coupling between nanorods and a gold-film substrate. We demonstrate that this coupling can be controlled by changing the gap between the silver nanorod array and gold substrate.

  13. Near-field coupling and resonant cavity modes in plasmonic nanorod metamaterials

    Science.gov (United States)

    Song, Haojie; Zhang, Junxi; Fei, Guangtao; Wang, Junfeng; Jiang, Kang; Wang, Pei; Lu, Yonghua; Iorsh, Ivan; Xu, Wei; Jia, Junhui; Zhang, Lide; Kivshar, Yuri S.; Zhang, Lin

    2016-10-01

    Plasmonic resonant cavities are capable of confining light at the nanoscale, resulting in both enhanced local electromagnetic fields and lower mode volumes. However, conventional plasmonic resonant cavities possess large Ohmic losses at metal-dielectric interfaces. Plasmonic near-field coupling plays a key role in a design of photonic components based on the resonant cavities because of the possibility to reduce losses. Here, we study the plasmonic near-field coupling in the silver nanorod metamaterials treated as resonant nanostructured optical cavities. Reflectance measurements reveal the existence of multiple resonance modes of the nanorod metamaterials, which is consistent with our theoretical analysis. Furthermore, our numerical simulations show that the electric field at the longitudinal resonances forms standing waves in the nanocavities due to the near-field coupling between the adjacent nanorods, and a new hybrid mode emerges due to a coupling between nanorods and a gold-film substrate. We demonstrate that this coupling can be controlled by changing the gap between the silver nanorod array and gold substrate.

  14. A detailed radiation heat transfer study of a dish-Stirling receiver: The impact of cavity wall radiation properties and cavity shapes

    Science.gov (United States)

    Garrido, Jorge; Wang, Wujun; Nilsson, Martin; Laumert, Björn

    2016-05-01

    A detailed 3-D radiation analysis of a dish-Stirling cavity receiver is carried out to estimate the cavity steady-state temperatures in order to assess the receiver integrity, lifetime and efficiency performance. For this purpose, a parabolic dish was modeled with 5.2 m focal length, 8.85 m aperture diameter and 2 mrad surface error. Three generic cavity shapes (cylindrical, diamond-shaped and reverse-conical) with three different emissivities (0.2, 0.4 and 0.7) are studied. Worst-case scenario heat generations (total absorbed radiation), maximum steady-state temperatures and energy balances of the cavities are calculated to evaluate the receiver performance. The results show that reverse-conical cavities can significantly reduce cavity wall peak temperatures (by 40-120 K), improve the temperature evenness and decrease the radiation losses by 4-5%. Regarding radiation properties, low reflectivities present lower steady-state temperatures even for low/moderate direct solar fluxes. Due to the lower temperatures, lower total thermal losses are also expected.

  15. 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.

  16. Q-switched operation of a coupled-resonator vertical-cavity laser diode

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-02-08

    The authors report Q-switched operation from an electrically-injected monolithic coupled-resonator structure which consists of an active cavity with InGaAs quantum wells optically coupled to a passive cavity. The passive cavity contains a bulk GaAs region which is reverse-biased to provide variable absorption at the lasing wavelength of 990 nm. Cavity coupling is utilized to effect large changes in output intensity with only very small changes in passive cavity absorption. The device is shown to produce pulses as short as 150 ps at repetition rates as high 4 GHz. A rate equation approach is used to model the Q-switched operation yielding good agreement between the experimental and theoretical pulse shape. Small-signal frequency response measurements also show a transition from a slower ({approximately} 300 MHZ) forward-biased modulation regime to a faster ({approximately} 2 GHz) modulation regime under reverse-bias operation.

  17. Free-Electron Laser as a Driver for a Resonant Cavity at 35 GHz

    Science.gov (United States)

    Lefevre, T.; Gardelle, J.; Rullier, J. L.; Vermare, C.; Donohue, J. T.; Meurdesoif, Y.; Lidia, S. M.

    2000-02-01

    An intense beam of relativistic electrons (800 A, 6.7 MeV) has been bunched at 35 GHz by a free-electron laser, in which output power levels exceeding 100 MW were obtained. The beam was then extracted and transported through a resonant cavity, which was excited by its passage. Microwave power levels of 10 MW were extracted from the cavity, in reasonable agreement with the simple formula which relates power to known properties of both the beam and the cavity.

  18. Pressure and kinetic energy transport across the cavity mouth in resonating cavities.

    Science.gov (United States)

    Bailey, Peter Roger; Abbá, Antonella; Tordella, Daniela

    2013-01-01

    Basic properties of the incompressible fluid motion in a rectangular cavity located along one wall of a plane channel are considered. For Mach numbers of the order of 1×10(-3) and using the incompressible formulation, we look for observable properties that can be associated with acoustic emission, which is normally observed in this kind of flow beyond a critical value of Reynolds number. The focus is put on the energy dynamics, in particular on the accumulation of energy in the cavity which takes place in the form of pressure and kinetic energy. By increasing the external forcing, we observe that the pressure flow into the cavity increases very rapidly, then peaks. However, the flow of kinetic energy, which is many orders of magnitude lower than that of the pressure, slowly but continuously grows. This leads to the pressure-kinetic energy flows ratio reaching an asymptotic state around the value 1000 for the channel bulk speed Reynolds number. It is interesting to note that beyond this threshold when the channel flow is highly unsteady-a sort of coarse turbulent flow-a sequence of high and low pressure spots is seen to depart from the downward cavity step in the statistically averaged field. The set of spots forms a steady spatial structure, a sort of damped standing wave stretching along the spanwise direction. The line joining the centers of the spots has an inclination similar to the normal to the fronts of density or pressure waves, which are observed to propagate from the downstream cavity edge in compressible cavity flows (at Mach numbers of 1×10(2) to 1×10(3), larger than those considered here). The wavelength of the standing wave is of the order of 1/8 the cavity depth and observed at the channel bulk Reynolds number, Re~2900. In this condition, the measure of the maximum pressure differences in the cavity field shows values of the order of 1×10(-1) Pa. We interpret the presence of this sort of wave as the fingerprint of the noise emission spots which

  19. Two-Dimensional Cavity Resonant Modes of Si Based Bragg Reflection Ridge Waveguide

    Institute of Scientific and Technical Information of China (English)

    CHEN San; Lu Hong-Yan; CHEN Kun-Ji; XU Jun; MA Zhong-Yuan; LI Wei; HUANG Xin-Fan

    2011-01-01

    @@ Si-based ridge-waveguides with Bragg reflectors are fabricated based on our method.Three resonant peaks could be obviously identified from the photoluminescence spectra, and field patterns of these resonant peaks, simulated by the finite difference time domain (FDTD) method, confirm that these peaks originate from cavity resonances.The resonant wavelengths and spatial angular distribution are given by the resonant models, which agree well with the experimental data.Experimentally, a simple method is proposed to testify the experimental and theoretical results.Such devices based on Bragg reflectors may have potential applications in light-emitting diodes, lasers and integrated photonic circuits.%Si-based ridge-waveguides with Bragg reflectors are fabricated based on our method. Three resonant peaks could be obviously identified from the photoluminescence spectra, and field patterns of these resonant peaks, simulated by the finite difference time domain (FDTD) method, confirm that these peaks originate from cavity resonances. The resonant wavelengths and spatial angular distribution are given by the resonant models, which agree well with the experimental data. Experimentally, a simple method is proposed to testify the experimental and theoretical results. Such devices based on Bragg reflectors may have potential applications in light-emitting diodes, lasers and integrated photonic circuits.

  20. Far-off-resonant coupling between a semiconductor quantum dot and an optical cavity

    DEFF Research Database (Denmark)

    Lund, Anders Mølbjerg; Settnes, Mikkel; Nielsen, Per Kær

    2014-01-01

    We present an investigation of the far-off-resonant coupling between a semiconductor quantum dot and a cavity. We show that the enhanced coupling observed in experiments is explained by Coulomb interactions with wetting layer carriers. © 2014 Optical Society of America.......We present an investigation of the far-off-resonant coupling between a semiconductor quantum dot and a cavity. We show that the enhanced coupling observed in experiments is explained by Coulomb interactions with wetting layer carriers. © 2014 Optical Society of America....

  1. Radiative feedback in Helmholtz resonators with more than one opening.

    Science.gov (United States)

    Dosch, Hans Günter

    2016-11-01

    The resonance frequency of a Helmholtz resonator with several openings is derived, taking into account the radiation feedback between the different holes. This is done under the assumption that the distance between the openings is large as compared to their linear dimensions. The effect of a finite wall thickness of the resonator is also discussed. The radiation feedback can lead to a shift of the resonance position by more than 10%.

  2. Ground-state cooling of a nanomechanical resonator via single-polariton optomechanics in a coupled quantum-dot-cavity system

    Science.gov (United States)

    Zhou, Ben-yuan; Li, Gao-xiang

    2016-09-01

    We propose a rapid ground-state optomechanical cooling scheme in a hybrid system, where a two-level quantum dot (QD) is placed in a single-mode cavity and a nanomechanical resonator (NMR) is also coupled to the cavity via radiation pressure. The cavity is driven by a weak laser field while the QD is driven by another weak laser field. Due to the quantum destructive interference arisen from different transition channels induced by simultaneously driving the QD-cavity system in terms of the two different lasers, two-photon absorption for the cavity field can be effectively eliminated by performing an optimal quantum interference condition. Furthermore, it is demonstrated that the QD-cavity system can be unbalancedly prepared in two single-polariton states with different eigenenergies. If the frequency of the NMR is tuned to be resonant with transition between two single-polariton states, it is found that a fast ground-state cooling for the NMR can also be achieved, even when the QD-cavity system is originally in the moderate-coupling regime. Thus the present ground-state cooling scheme for the NMR may be realized with currently available experimental technology.

  3. Excitation and tuning of Fano-like cavity plasmon resonances in dielectric-metal core-shell resonators

    Science.gov (United States)

    Gu, Ping; Wan, Mingjie; Wu, Wenyang; Chen, Zhuo; Wang, Zhenlin

    2016-05-01

    Fano resonances have been realized in plasmonic systems and have found intriguing applications, in which, however, precisely controlled symmetry breaking or particular arrangement of multiple constituents is usually involved. Although simple core-shell type architectures composed of a spherical dielectric core and a concentric metallic shell layer have been proposed as good candidates that support inherent Fano resonances, these theoretical predictions have rarely seen any detailed experimental investigation. Here, we report on the experimental investigation of the magnetic and electric-based multipolar plasmonic Fano resonances in the dielectric-metal core-shell resonators that are formed by wrapping a nearly perfect metal shell layer around a dielectric sphere. We demonstrate that these Fano resonances originate from the interference between the Mie cavity and sphere plasmon resonances. Moreover, we present that the variation on either the dielectric core size or core refractive index allows for easily tuning the observed Fano resonances over a wide spectral range. Our findings are supported by excellent agreement with analytical calculations, and offer unprecedented opportunities for realizing ultrasensitive bio-sensors, lasing and nonlinear optical devices.Fano resonances have been realized in plasmonic systems and have found intriguing applications, in which, however, precisely controlled symmetry breaking or particular arrangement of multiple constituents is usually involved. Although simple core-shell type architectures composed of a spherical dielectric core and a concentric metallic shell layer have been proposed as good candidates that support inherent Fano resonances, these theoretical predictions have rarely seen any detailed experimental investigation. Here, we report on the experimental investigation of the magnetic and electric-based multipolar plasmonic Fano resonances in the dielectric-metal core-shell resonators that are formed by wrapping a

  4. Exploring the distinction between experimental resonant modes and theoretical eigenmodes: From vibrating plates to laser cavities

    Science.gov (United States)

    Tuan, P. H.; Wen, C. P.; Yu, Y. T.; Liang, H. C.; Huang, K. F.; Chen, Y. F.

    2014-02-01

    Experimentally resonant modes are commonly presumed to correspond to eigenmodes in the same bounded domain. However, the one-to-one correspondence between theoretical eigenmodes and experimental observations is never reached. Theoretically, eigenmodes in numerous classical and quantum systems are the solutions of the homogeneous Helmholtz equation, whereas resonant modes should be solved from the inhomogeneous Helmholtz equation. In the present paper we employ the eigenmode expansion method to derive the wave functions for manifesting the distinction between eigenmodes and resonant modes. The derived wave functions are successfully used to reconstruct a variety of experimental results including Chladni figures generated from the vibrating plate, resonant patterns excited from microwave cavities, and lasing modes emitted from the vertical cavity.

  5. Cavity Quantum Electrodynamics in a wide aperture spherical resonator. Part II Vacuum-field atom trapping

    CERN Document Server

    Daul, J M; Daul, Jean-Marc; Grangier, Philippe

    2003-01-01

    We consider the situation where a two-level atom is placed in the vicinity of the center of a spherical cavity with a large numerical aperture. The vacuum field at the center of the cavity is actually equivalent to the one obtained in a microcavity, and both the dissipative and the reactive parts of the atom's spontaneous emission are significantly modified. Using an explicit calculation of the spatial dependence of the radiative relaxation rate and of the associated level shift, we show that for a weakly excitating light field, the atom can be attracted to the center of the cavity by vacuum-induced light shifts.

  6. Electrical conductivity of Jupiter's shallow interior and the formation of a resonant of a resonant planetary-ionospheric cavity

    Science.gov (United States)

    Sentman, D. D.

    1990-01-01

    The present consideration of hydrogenic atmospheric reactions on Jupiter, to a depth of 4000 km, notes the primary ion constituents at these depths to be both positive and negative ions of molecular hydrogen contributing less than 20 percent to total electrical conductivity by free electrons. An electrical surface defined by the boundary beneath which the interior is electrically conducting exists at depths which vary according to EM wave frequency, from 1100 km for 1 mHz to 3000 for 1 MHz. The presence of a lower electrical boundary within the shallow interior suggests that a planetary-ionosphere resonant cavity analogous to the earth-ionosphere cavity may exist.

  7. Resonant-frequency discharge in a multi-cell radio frequency cavity

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, S; Upadhyay, J; Mammosser, J; Nikolic, M; Vuskovic, L

    2014-11-07

    We are reporting experimental results on microwave discharge operating at resonant frequency in a multi-cell radio frequency (RF) accelerator cavity. Although the discharge operated at room temperature, the setup was constructed so that it could be used for plasma generation and processing in fully assembled active superconducting radio-frequency (SRF) cryomodule (in situ operation). This discharge offers an efficient mechanism for removal of a variety of contaminants, organic or oxide layers, and residual particulates from the interior surface of RF cavities through the interaction of plasma-generated radicals with the cavity walls. We describe resonant RF breakdown conditions and address the problems related to generation and sustaining the multi-cell cavity plasma, which are breakdown and resonant detuning. We have determined breakdown conditions in the cavity, which was acting as a plasma vessel with distorted cylindrical geometry. We discuss the spectroscopic data taken during plasma removal of contaminants and use them to evaluate plasma parameters, characterize the process, and estimate the volatile contaminant product removal.

  8. Resonant-frequency discharge in a multi-cell radio frequency cavity

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, S; Upadhyay, J; Mammosser, J; Nikolic, M; Vuskovic, L

    2014-11-07

    We are reporting experimental results on microwave discharge operating at resonant frequency in a multi-cell radio frequency (RF) accelerator cavity. Although the discharge operated at room temperature, the setup was constructed so that it could be used for plasma generation and processing in fully assembled active superconducting radio-frequency (SRF) cryomodule (in situ operation). This discharge offers an efficient mechanism for removal of a variety of contaminants, organic or oxide layers, and residual particulates from the interior surface of RF cavities through the interaction of plasma-generated radicals with the cavity walls. We describe resonant RF breakdown conditions and address the problems related to generation and sustaining the multi-cell cavity plasma, which are breakdown and resonant detuning. We have determined breakdown conditions in the cavity, which was acting as a plasma vessel with distorted cylindrical geometry. We discuss the spectroscopic data taken during plasma removal of contaminants and use them to evaluate plasma parameters, characterize the process, and estimate the volatile contaminant product removal.

  9. Properties of Optical Resonant Modes in Ⅲ-Nitride Semiconductor Micro-Cone Cavities

    Institute of Scientific and Technical Information of China (English)

    DAI Lun; ZHANG Bei; LIN Jing-Yu; JIANG Hong-Xing

    2001-01-01

    Arrays of Ⅲ-nitride semiconductor micro-cone cavities with a base diameter of 3.3μm were fabricated by ion beam etching. The micro-cones consisted of 58 nm thick multiple quantum wells of ln0.22Ga0.78N/In0.06Ga0.94N as well as a 1.5μm thick epilayer of GaN. Optical resonant modes from a single micro-cone could be clearly observed in the photoluminescence spectra at temperatures up to 200K under a pumping power density two orders of magnitude lower than that for the Ⅲ-nitride semiconductor micro-disk or micro-ring cavity. Using a novel optical ray tracing method, we have figured out four main types of optical resonant cavities inside the three-dimensional micro-cone, including two Fabry-Perot (F-P) mode types as well as two Whispering Gallery mode types. The three corresponding mode spacings among the four agree perfectly with the experimental results. The advantages of this new class of micro-cavity over the other micro-cavities are discussed. These findings are expected to have an impact on the design of the ultraviolet/blue micro-cavity laser diodes.

  10. Stabilization of nonclassical states of the radiation field in a cavity by reservoir engineering.

    Science.gov (United States)

    Sarlette, A; Raimond, J M; Brune, M; Rouchon, P

    2011-07-01

    We propose an engineered reservoir inducing the relaxation of a cavity field towards nonclassical states. It is made up of two-level atoms crossing the cavity one at a time. Each atom-cavity interaction is first dispersive, then resonant, then dispersive again. The reservoir pointer states are those produced by an effective Kerr Hamiltonian acting on a coherent field. We thereby stabilize squeezed states and quantum superpositions of multiple coherent components in a cavity having a finite damping time. This robust decoherence protection method could be implemented in state-of-the-art experiments.

  11. Optimal dielectric and cavity configurations for improving the efficiency of electron paramagnetic resonance probes.

    Science.gov (United States)

    Elnaggar, Sameh Y; Tervo, Richard; Mattar, Saba M

    2014-08-01

    An electron paramagnetic resonance (EPR) spectrometer's lambda efficiency parameter (Λ) is one of the most important parameters that govern its sensitivity. It is studied for an EPR probe consisting of a dielectric resonator (DR) in a cavity (CV). Expressions for Λ are derived in terms of the probe's individual DR and CV components, Λ1 and Λ2 respectively. Two important cases are considered. In the first, a probe consisting of a CV is improved by incorporating a DR. The sensitivity enhancement depends on the relative rather than the absolute values of the individual components. This renders the analysis general. The optimal configuration occurs when the CV and DR modes are nearly degenerate. This configuration guarantees that the probe can be easily coupled to the microwave bridge while maintaining a large Λ. It is shown that for a lossy CV with a small quality factor Q2, one chooses a DR that has the highest filling factor, η1, regardless of its Λ1 and Q1. On the other hand, if the CV has a large Q2, the optimum DR is the one which has the highest Λ1. This is regardless of its η1 and relative dielectric constant, ɛr. When the quality factors of both the CV and DR are comparable, the lambda efficiency is reduced by a factor of 2. Thus the signal intensity for an unsaturated sample is cut in half. The second case is the design of an optimum shield to house a DR. Besides preventing radiation leakage, it is shown that for a high loss DR, the shield can actually boost Λ above the DR value. This can also be very helpful for relatively low efficiency dielectrics as well as lossy samples, such as polar liquids.

  12. Temporal coupled mode theory of standing wave resonant cavities for infrared photodetection.

    Science.gov (United States)

    Lesmanne, Emeline; De Lamaestre, Roch Espiau; Fowler, David; Boutami, Salim; Badano, Giacomo

    2015-03-23

    Standing wave resonating cavities have been proposed in the past to increase the performance of infrared detectors by minimizing the volume of photogeneration, hence the noise, while maintaining the same quantum efficiency. We present an approach based on the temporal coupled mode theory to explain their behavior and limitations. If the ratio of the imaginary part of the absorber's dielectric function to the index of the incident medium ε″(d)/n₀ is larger than 1.4, then the absorption cross section σ(a) can attain its maximum value, which for an isolated cavity is approximately 2λ/π. Besides, for σ(a) to exceed the cavity width, the incident medium refractive index must be close to unity. Metallic loss is negligible in the infrared, making those resonators suitable for integration in infrared photodetectors.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. 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...

  15. Normalization of quasinormal modes in leaky optical cavities and plasmonic resonators

    CERN Document Server

    Kristensen, Philip Trøst; Hughes, Stephen

    2015-01-01

    We discuss three formally different formulas for normalization of quasinormal modes currently in use for modeling optical cavities and plasmonic resonators and show that they are complementary and provide the same result. Regardless of the formula used for normalization, one can use the norm to define an effective mode volume for use in Purcell factor calculations.

  16. Noise reduction in double-panel structures by cavity and panel resonance control

    NARCIS (Netherlands)

    Ho, J.-H.; Berkhoff, A.P

    2011-01-01

    This paper presents an investigation of the cavity and the panel resonance control in a double‐panel structure. The double‐panel structure, which consists of two panels with air in the gap, is widely adopted in many applications such as aerospace due to its light weight and effective transmission‐lo

  17. Entanglement of resonantly coupled field modes in cavities with vibrating boundaries

    CERN Document Server

    Andreata, M A; Dodonov, V V

    2002-01-01

    We study time dependence of various measures of entanglement (covariance entanglement coefficient, purity entanglement coefficient, normalized distance coefficient, entropic coefficients) between resonantly coupled modes of the electromagnetic field in ideal cavities with oscillating boundaries. Two types of cavities are considered: a three-dimensional cavity possessing eigenfrequencies $\\omega_3=3\\omega_1$, whose wall oscillates at the frequency $\\omega_w=2\\omega_1$, and a one-dimensional (Fabry--Perot) cavity with an equidistant spectrum $\\omega_n= n\\omega_1$, when the distance between perfect mirrors oscillates at the frequencies $\\omega_1$ and $2\\omega_1$. The behaviour of entanglement measures in these cases turns out to be completely different, although all three coefficients demonstrate qualitatively similar time dependences in each case (except for some specific situations, where the covariance entanglement coefficient, based on traces of covariance submatrices, seems to be essentially more sensitive ...

  18. Realization of cavity linewidth narrowing via interacting dark resonances in a tripod-type electromagnetically induced transparency system

    CERN Document Server

    Ying, Kang; Chen, Dijun; Cai, Haiwen; Qu, Ronghui

    2014-01-01

    Cavity linewidth narrowing via double-dark resonances has been experimentally observed using the 87Rb Zeeman splitting sublevels. With the steep dispersion led by the interacting dark resonances in the tripodtype electromagnetically induced transparency system, we narrow the cavity linewidth to 250 KHz at room temperature. Furthermore, the position of this ultranarrow cavity linewidth could be tuned in a 60 MHz coupling field detuning range.

  19. Investigation of the resonance frequency and performance of a partially plasma filled reconfigurable cylindrical TE111 mode cavity

    Science.gov (United States)

    Hadaegh, Mostafa; Mohajeri, Farzad

    2017-05-01

    A partially plasma filled reconfigurable cylindrical cavity is proposed. Plasma offers an encouraging alternative to metal for a wide variety of microwave engineering applications. Implementation of a low-cost plasma element permits the resonant frequency to be changed electrically. The level of the resonant frequency shifts toward the empty-cavity resonant frequency and depends on certain parameters, such as the plasma diameter, relative permittivity and thickness of the plasma tube. In this article, we first introduce the partially plasma filled reconfigurable cylindrical cavity; then, the resonant frequency equation of the cavity is obtained by variational methods. Finally, we plot the resonant frequency versus different parameters of the cavity, which we compare with the results of the CST software. We show that the two results are compatible with each other.

  20. Electron density and collision frequency of microwave resonant cavity produced discharges. [Progress report

    Energy Technology Data Exchange (ETDEWEB)

    McColl, W.; Brooks, C.; Brake, M.L.

    1992-12-31

    This progress report consists of an article, the abstract of which follows, and apparently the references and vita from a proposal. A review of perturbation diagnostics applied to microwave resonant cavity discharges is presented. The classical microwave perturbation technique examines the shift in the resonant frequency and cavity quality factor of the resonant cavity caused by low electron density discharges. However, modifications presented here allow the analysis to be applied to discharges with electron densities beyond the limit predicted by perturbation theory. An {open_quote}exact{close_quote} perturbation analysis is presented which models the discharge as a separate dielectric, thereby removing the restrictions on electron density imposed by the classical technique. The {open_quote}exact{close_quote} method also uses measurements of the shifts in the resonant conditions of the cavity. Thirdly, an electromagnetic analysis is presented which uses a characteristic equation, based upon Maxwell`s laws, and predicts the discharge conductivity based upon measurements of a complex axial wave number. By allowing the axial wave number of the electromagnetic fields to be complex, the fields are experimentally and theoretically shown to be spatially attenuated. The diagnostics are applied to continuous-wave microwave (2.45 GHz) discharges produced in an Asmussen resonant cavity. Double Langmuir probes, placed directly in the discharge at the point where the radial electric field is zero, act as a comparison with the analytic diagnostics. Microwave powers ranging from 30 to 100 watts produce helium and nitrogen discharges with pressures ranging from 0.5 to 6 torr. Analysis of the data predicts electron temperatures from 5 to 20 eV, electron densities from 10{sup 11} to 3 {times} 10{sup 12} cm{sup {minus}3}, and collision frequencies from 10{sup 9} to 10{sup 11} sec{sup {minus}1}.

  1. 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

  2. A study of resonant-cavity and fiberglass-filled parallel baffles as duct silencers. [for wind tunnels

    Science.gov (United States)

    Soderman, P. T.

    1982-01-01

    Acoustical performance and pressure drop were measured for two types of splitters designed to attenuate sound propagating in ducts - resonant-cavity baffles and fiberglass-filled baffles. Arrays of four baffles were evaluated in the 7- by 10-foot wind tunnel number 1 at Ames Research Center at flow speeds from 0 to 41 m/sec. The baffles were 2.1 m high, 305 to 406 mm thick, and 3.1 to 4.4 m long. Emphasis was on measurements of silencer insertion loss as affected by variations of such parameters as baffle length, baffle thickness, perforated skin geometry, cavity size and shape, cavity damping, wind speed, and acoustic field directivity. An analytical method for predicting silencer performance is described and compared with measurements. With the addition of cavity damping in the form of 25-mm foam linings, the insertion loss above 250 Hz of the resonant-cavity baffles was improved 2 to 7 db compared with the undamped baffles; the loss became equal to or greater than the insertion loss of comparable size fiberglass baffles at frequencies above 250 Hz. Variations of cavity size and shape showed that a series of cavities with triangular cross-sections (i.e., variable depth) were superior to cavities with rectangular cross sections (i.e., constant depth). In wind, the undamped, resonant-cavity baffles generated loud cavity-resonance tones; the tones could be eliminated by cavity damping.

  3. A research on high-temperature permittivity and loss tangent of low-loss dielectric by resonant-cavity technique

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Resonant-cavity technique was introduced to measure the permittivity and loss tangent of low-loss dielectrics. The dielectric properties at 9-10 GHz are measured accurately at the temperature up to 800 ℃by the resonant cavity technique. The only electrical parameters that need to be measured are quality factors (Q) and resonant length (L) of resonant cavity loaded and unloaded with dielectric sample. Moreover, the error caused by thermal expansion effect was resolved by error analysis and experimental calibration.

  4. Designing and Dosimetry of a Shield for Photon Fields of Radiation Therapy in Oral Cavity Cancer

    OpenAIRE

    Jabbari, Keyvan; Senobari, Somayeh; Roayaei, Mahnaz; Rostampour, Masoumeh

    2015-01-01

    The cancer of oral cavity is related to lesions of mucous membrane of tongue and gum that can be treated with radiation therapy. A lateral photon field can be used to treat this kind of tumor, which has a side-effect on normal tissue in the opposite side of the oral cavity. In this study the dosimetric effect of the various shields in oral cavity is evaluated. In this study, a special phantom similar to the structure of oral cavity with capability of film dosimetry was designed and constructe...

  5. Resonant-Cavity Driven Alfvén Waves in a Helium-Hydrogen Plasma

    Science.gov (United States)

    Clark, Mary; Dorfman, Seth; Vincena, Steve; Zhu, Ziyan; Carter, Troy

    2016-10-01

    Alfvén waves exist in many regimes. In fusion experiments, they can disrupt fusion processes by scattering particles, and in space, they are proposed to heat the solar corona. In these environments, multiple ion species usually occur. It is therefore relevant to study Alfvén waves carried by multiple ion species in a laboratory device. Here a resonant cavity launches them in UCLA's Large Plasma Device (LaPD) in a helium/hydrogen plasma. In a two-ion species plasma, Alfvén waves propagate in two bands: below the heavy ion cyclotron frequency and between a hybrid frequency and the light ion cyclotron frequency. We observe two Alfvén waves at different frequencies (in different bands) emerge when the resonant cavity is excited at one frequency: one at the driving frequency and one at a lower frequency. The two frequencies and wavelengths agree with the dispersion relation. The resonant cavity theory predicts that the wavelengths should be 4 times the cavity's length; only the high frequency lies close to this prediction. This work was funded by UCLA's Norton Rodman Award, and was performed at the Basic Plasma Science Facility, funded by DoE and NSF.

  6. Multiple harmonic frequencies resonant cavity design and half-scale prototype measurements for a fast kicker

    Science.gov (United States)

    Huang, Yulu; Wang, Haipeng; Rimmer, Robert A.; Wang, Shaoheng; Guo, Jiquan

    2016-12-01

    Quarter wavelength resonator (QWR) based deflecting cavities with the capability of supporting multiple odd-harmonic modes have been developed for an ultrafast periodic kicker system in the proposed Jefferson Lab Electron Ion Collider (JLEIC, formerly MEIC). Previous work on the kicking pulse synthesis and the transverse beam dynamics tracking simulations show that a flat-top kicking pulse can be generated with minimal emittance growth during injection and circulation of the cooling electron bunches. This flat-top kicking pulse can be obtained when a DC component and 10 harmonic modes with appropriate amplitude and phase are combined together. To support 10 such harmonic modes, four QWR cavities are used with 5, 3, 1, and 1 modes, respectively. In the multiple-mode cavities, several slightly tapered segments of the inner conductor are introduced to tune the higher order deflecting modes to be harmonic, and stub tuners are used to fine tune each frequency to compensate for potential errors. In this paper, we summarize the electromagnetic design of the five-mode cavity, including the geometry optimization to get high transverse shunt impedance, the frequency tuning and sensitivity analysis, and the single loop coupler design for coupling to all of the harmonic modes. In particular we report on the design and fabrication of a half-scale copper prototype of this proof-of-principle five-odd-mode cavity, as well as the rf bench measurements. Finally, we demonstrate mode superposition in this cavity experimentally, which illustrates the kicking pulse generation concept.

  7. Cavities

    Science.gov (United States)

    ... may pass these bacteria to a child through kissing, sampling the child's food, or sharing eating utensils. ... pass decay-causing bacteria to their children through kissing or sharing eating utensils. Symptoms of Cavities Whether ...

  8. Super-resonant radiation stimulated by high-harmonics

    CERN Document Server

    Loures, Cristian Redondo; Faccio, Daniele; Biancalana, Fabio

    2016-01-01

    Solitons propagating in media with higher order dispersion will shed radiation known as dispersive wave or resonant radiation, with applications in frequency broadening, deep UV sources for spectroscopy or simply fundamental studies of soliton physics. Starting from a recently proposed equation that models the behaviour of ultrashort optical pulses in nonlinear materials using the analytic signal, we find that the resonant radiation associated with the third-harmonic generation term of the equation is parametrically stimulated with an unprecedented gain. Resonant radiation levels, typically only a small fraction of the soliton, are now as intense as the soliton itself. The mechanism is quite universal and works also in normal dispersion and with harmonics higher than the third. We report experimental hints of this super-resonant radiation stimulated by the fifth harmonic in diamond.

  9. Phase Noise Enhancement of the GaAs High Electron Mobility Transistors Using Micromachined Cavity Resonators at Ka-band

    Science.gov (United States)

    Song, Insang; Kim, Chungwoo; Kwon, Youngwoo; Cheon, Changyul; Song, Cimoo

    1999-06-01

    We introduce a new structure of the micromachined cavity resonator coupled GaAs-based oscillator to enhance the phase noise and the frequency stability. The oscillator and the cavity are designed for Ka-band applications. Compared to the free running oscillator, the cavity resonator coupled oscillator showed the phase noise enhancement of about 20 dB. The phase noises of about -110 and -85 dBc/Hz are obtained at 1 MHz and 100 kHz offset frequency, respectively. The frequency pushing for the gate bias of the cavity coupled oscillator is about two order of magnitude less than that of the free running oscillator.

  10. Generation of GHZ entangled states of photons in multiple cavities via a superconucting qubit or an atom through resonant interaction

    CERN Document Server

    Yang, Chui-Ping

    2012-01-01

    We propose a method to generate a GHZ entangled state of n photons in n microwave cavities (or resonators) via resonant interaction to a single superconducting qubit. By performing local operations on a qubit (e.g., a solid-state qubit, an atom, etc.) placed in each cavity, the created GHZ states of n photons can be transferred to qubits for storage. The proposed scheme greatly reduces effect of decoherence since only resonant qubit-cavity interaction and resonant qubit-pulse interaction are involved, and no measurement is required. In addition, we show that the method can be applied to create a GHZ state of photons in multiple cavities via an atom through resonant interaction with no measurement needed.

  11. Strongly enhanced and directionally tunable second-harmonic radiation from a plasmonic particle-in-cavity nanoantenna

    Science.gov (United States)

    Xiong, Xiaoyan Y. Z.; Jiang, Li Jun; Sha, Wei E. I.; Lo, Yat Hei; Fang, Ming; Chew, Weng Cho; Choy, Wallace C. H.

    2016-11-01

    Second-harmonic (SH) generation is tremendously important for nonlinear sensing, microscopy, and communication systems. One of the great challenges of current designs is to enhance the SH signal and simultaneously tune its radiation direction with a high directivity. In contrast to the linear plasmonic scattering dominated by a bulk dipolar mode, a complex surface-induced multipolar source at the doubled frequency sets a fundamental limit to control the SH radiation from metallic nanostructures. In this work, we harness a plasmonic hybridization mechanism together with a special selection rule governing the SH radiation to achieve the high-intensity and tunable-direction emission by a metallic particle-in-cavity nanoantenna (PIC-NA). The nanoantenna is modelled with a first-principle, self-consistent boundary element method, which considers the depletion of pump waves. The giant SH enhancement arises from a hybridized gap plasmon resonance between the small particle and the large cavity that functions as a concentrator and reflector. Centrosymmetry breaking of the PIC-NA not only modifies the gap plasmon mode boosting the SH signal, but also redirects the SH wave with a unidirectional emission. The PIC-NA has a significantly larger SH conversion efficiency compared to existing literature. The main beam of the radiation pattern can be steered over a wide angle by tuning the particle's position.

  12. Electromagnetic Response of High-Frequency Gravitational Waves by Coupling Open Resonant Cavity

    Institute of Scientific and Technical Information of China (English)

    LI Fang-Yu; CHEN Ying; WANG Ping

    2007-01-01

    We present a new detecting scheme of high-frequency gravitational waves(HFGWs) in the GHz band,the scheme consists of a high-quality-factor open microwave cavity,a static magnetic field passing through the cavity and an electromagnetic (EM)normal mode stored in the cavity.It is found that under the resonant condition firstand second-order perturbation EM effects have almost the same detecting sensitivity to the HFGWs in the GHz band (h~10-26,v~5GHz),but the former contains more information from the HFGWs.We akso provide a very brief review for possible improving way of the sensitivity.This scheme would be Highly complementary to other schemes of detecting the HFGWs.

  13. High-Precision Resonant Cavity Beam Position, Emittance And Third-Moment Monitors

    Energy Technology Data Exchange (ETDEWEB)

    Barov, N.; Kim, J.S.; Weidemann, A.W.; /FARTECH, San Diego; Miller, R.H.; Nantista, C.D.; /SLAC

    2006-03-14

    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., in collaboration with SLAC, 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 standing-wave structure further enhances signal strength and improves the resolution of the device. An estimated resolution is better than 1 {micro}m in rms beam size and better than 1 nm in beam position.

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

    Science.gov (United States)

    Sergeant, Nicholas P; Niesen, Bjoern; Liu, Albert S; Boman, Lee; Stoessel, Chris; Heremans, Paul; Peumans, Peter; Rand, Barry P; Fan, Shanhui

    2013-05-01

    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 Zn(x)Sn(y)O(z)/Ag/In(x)Sn(y)O(z)) 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.

  15. An unobtrusive liquid sensor utilizing a micromilled RF spark gap transmitter and resonant cavity

    Science.gov (United States)

    Berry, H.; Wilson, C.

    2009-09-01

    This paper reports on a new dielectric liquid sensor that utilizes an RF sparkgap transmitter coupled with an aluminum microwave resonant cavity. The transmitter is a micromilled polymer transmitter housing with patterned copper electrodes that generate micro-arcs. This transmitter which operates outside the measured liquid generates a directed ultrawideband signal which is received by the aluminum waveguide. Absorption resonances in the microwave cavity, measured with a spectrum analyzer are a function of the liquids' dielectric constant at lower frequencies, as well as from molecular vibrations/rotations at higher frequencies. In many chemical manufacturing processes, liquids being manufactured are removed, tested in a lab, and then disposed of, or else they will contaminate the full batch. In beer brewing, for instance, samples are removed, density tested for alcohol content, then disposed of. Using this sensor, the chemical process could be continuously monitored by a computerized system without risk of contamination.

  16. High-performance Refractive Index Sensor Based on Photonic Crystal Single Mode Resonant Micro-cavity

    Institute of Scientific and Technical Information of China (English)

    Shengye Huang; Junfeng Shi; Dongsheng Wang; Wei Li

    2006-01-01

    An effective refractive index sensor built with square lattice photonic crystal is proposed, which can be applicable to photonic integrated circuits. Two photonic crystal waveguides rather than conventional ridge waveguides are used as entrance/exit waveguides to the micro-cavity. Three layers of photonic lattice are set between the photonic crystal waveguides and the micro-cavity to achieve both a high transmission and a high sensitivity. The plane wave method is utilized to calculate the disperse curves and the finite difference time domain scheme is employed to simulate the light propagation. At the resonant wavelength of about 1500 nm, the resonant wavelength shifts up by 0.7 nm for each increment of △n=0.001. A transmission of more than 0.75 is observed. Although the position disorder of the photonic crystal doesn't affect the sensitivity of the sensor,the transmission reduces rapidly as the disorder increases.

  17. 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.

  18. High-efficiency degenerate four wave-mixing in triply resonant nanobeam cavities

    CERN Document Server

    Lin, Zin; Loncar, Marko; Johnson, Steven G; Rodriguez, Alejandro W

    2013-01-01

    We demonstrate high-efficiency, degenerate four-wave mixing in triply resonant Kerr $\\chi^(3)$ photonic crystal (PhC) nanobeam cavities. Using a combination of temporal coupled mode theory and nonlinear finite-difference time-domain (FDTD) simulations, we study the nonlinear dynamics of resonant four-wave mixing processes and demonstrate the possibility of observing high-efficiency limit cycles and steady-state conversion corresponding to $\\approx 100$% depletion of the pump light at low powers, even including effects due to losses, self- and cross-phase modulation, and imperfect frequency matching. Assuming operation in the telecom range, we predict close to perfect quantum efficiencies at reasonably low $\\sim$ 50 mW input powers in silicon micrometer-scale cavities.

  19. Electrically detected magnetic resonance in a W-band microwave cavity

    Energy Technology Data Exchange (ETDEWEB)

    Lang, V.; Lo, C. C.; George, R. E.; Lyon, S. A.; Bokor, J.; Schenkel, T.; Ardavan, A.; Morton, J. J. L.

    2011-01-14

    We describe a low-temperature sample probe for the electrical detection of magnetic resonance in a resonant W-band (94 GHz) microwave cavity. The advantages of this approach are demonstrated by experiments on silicon field-effect transistors. A comparison with conventional low-frequency measurements at X-band (9.7 GHz) on the same devices reveals an up to 100-fold enhancement of the signal intensity. In addition, resonance lines that are unresolved at X-band are clearly separated in the W-band measurements. Electrically detected magnetic resonance at high magnetic fields and high microwave frequencies is therefore a very sensitive technique for studying electron spins with an enhanced spectral resolution and sensitivity.

  20. Coherent quantum state storage and transfer between two phase qubits via a resonant cavity.

    Science.gov (United States)

    Sillanpää, Mika A; Park, Jae I; Simmonds, Raymond W

    2007-09-27

    As with classical information processing, a quantum information processor requires bits (qubits) that can be independently addressed and read out, long-term memory elements to store arbitrary quantum states, and the ability to transfer quantum information through a coherent communication bus accessible to a large number of qubits. Superconducting qubits made with scalable microfabrication techniques are a promising candidate for the realization of a large-scale quantum information processor. Although these systems have successfully passed tests of coherent coupling for up to four qubits, communication of individual quantum states between superconducting qubits via a quantum bus has not yet been realized. Here, we perform an experiment demonstrating the ability to coherently transfer quantum states between two superconducting Josephson phase qubits through a quantum bus. This quantum bus is a resonant cavity formed by an open-ended superconducting transmission line of length 7 mm. After preparing an initial quantum state with the first qubit, this quantum information is transferred and stored as a nonclassical photon state of the resonant cavity, then retrieved later by the second qubit connected to the opposite end of the cavity. Beyond simple state transfer, these results suggest that a high-quality-factor superconducting cavity could also function as a useful short-term memory element. The basic architecture presented here can be expanded, offering the possibility for the coherent interaction of a large number of superconducting qubits.

  1. Resonance frequency shift in a cavity with a thin conducting film near a conducting wall

    Energy Technology Data Exchange (ETDEWEB)

    Braggio, C. [Dipartimento di Fisica, Universita di Ferrara and INFN, Via del Paradiso 12, 44100 Ferrara (Italy)]. E-mail: caterina.braggio@lnl.infn.it; Bressi, G. [INFN, Sezione di Pavia, Via Bassi 6, 27100 Pavia (Italy); Carugno, G. [INFN, Sezione di Padova, Via F. Marzolo 8, 35131 Padova (Italy); Dodonov, A.V. [Departamento de Fisica, Universidade Federal de Sao Carlos, Via Washington Luiz, Km 235, Sao Carlos 13565-905, SP (Brazil); Dodonov, V.V. [Instituto de Fisica, Universidade de Brasilia, Caixa Postal 04455, 70910-900 Brasilia, DF (Brazil)]. E-mail: vdodonov@fis.unb.br; Galeazzi, G. [INFN, LNL, Viale dell' Universita 2, 35020 Legnaro (Italy); Ruoso, G. [INFN, LNL, Viale dell' Universita 2, 35020 Legnaro (Italy); Zanello, D. [INFN, Sezione di Roma, Piazzale A. Moro 2, 00185 Roma (Italy)

    2007-03-19

    We show that a very thin conducting film (whose thickness can be much smaller than the skin depth), placed nearby a wall of an electromagnetic cavity, can produce the same shift of the resonance frequency as a bulk conducting slab, provided the displacement of the film from the wall is much bigger than the skin depth. We derive a simple analytical formula for the frequency shift and compare it with exact numerical calculations and experimental data.

  2. High-Q silica zipper cavity for optical radiation pressure driven MOMS switch

    CERN Document Server

    Tetsumoto, Tomohiro

    2014-01-01

    We design a silica zipper cavity that has high optical and mechanical Q (quality factor) values and demonstrate numerically the feasibility of a radiation pressure driven micro opto-mechanical system (MOMS) directional switch. The silica zipper cavity has an optical Q of 6.0x10^4 and an effective mode volume Vmode of 0.66{\\lambda}^3 when the gap between two cavities is 34 nm. We found that this Q/V_mode value is five times higher than can be obtained with a single nanocavity design. The mechanical Q (Q_m) is determined by thermo-elastic damping and is 2.0x10^6 in a vacuum at room temperature. The opto-mechanical coupling rate g_OM is as high as 100 GHz/nm, which allows us to move the directional cavity-waveguide system and switch 1550-nm light with 770-nm light by controlling the radiation pressure.

  3. Non-invasive temperature measurement by using phase changes in electromagnetic waves in a cavity resonator.

    Science.gov (United States)

    Ishihara, Yasutoshi; Ohwada, Hiroshi

    2011-01-01

    To improve the efficacy of hyperthermia treatment, a novel method of non-invasive measurement of changes in body temperature is proposed. The proposed method is based on phase changes with temperature in electromagnetic waves in a heating applicator and the temperature dependence of the dielectric constant. An image of the temperature change inside a body is reconstructed by applying a computed tomography algorithm. This method can be combined easily with a heating applicator based on a cavity resonator and can be used to treat cancer effectively while non-invasively monitoring the heating effect. In this paper the phase change distributions of electromagnetic waves with temperature changes are measured experimentally, and the accuracy of reconstruction is discussed. The phase change distribution is reconstructed by using a prototype system with a rectangular aluminum cavity resonator that can be rotated 360° around an axis of rotation. To make measurements without disturbing the electromagnetic field distribution, an optical electric field sensor is used. The phase change distribution is reconstructed from 4-projection data by using a simple back-projection algorithm. The paper demonstrates that the phase change distribution can be reconstructed. The difference between phase changes obtained experimentally and by numerical analysis is about 20% and is related mainly to the limited signal detection sensitivity of electromagnetic waves. A temperature change inside an object can be reconstructed from the measured phase changes in a cavity resonator.

  4. 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.)

  5. Cavity Optical Pulse Extraction: ultra-short pulse generation as seeded Hawking radiation.

    Science.gov (United States)

    Eilenberger, Falk; Kabakova, Irina V; de Sterke, C Martijn; Eggleton, Benjamin J; Pertsch, Thomas

    2013-01-01

    We show that light trapped in an optical cavity can be extracted from that cavity in an ultrashort burst by means of a trigger pulse. We find a simple analytic description of this process and show that while the extracted pulse inherits its pulse length from that of the trigger pulse, its wavelength can be completely different. Cavity Optical Pulse Extraction is thus well suited for the development of ultrashort laser sources in new wavelength ranges. We discuss similarities between this process and the generation of Hawking radiation at the optical analogue of an event horizon with extremely high Hawking temperature. Our analytic predictions are confirmed by thorough numerical simulations.

  6. Optically tunable Fano resonance in a grating-based Fabry-Perot cavity-coupled microring resonator on a silicon chip.

    Science.gov (United States)

    Zhang, Weifeng; Li, Wangzhe; Yao, Jianping

    2016-06-01

    A grating-based Fabry-Perot (FP) cavity-coupled microring resonator on a silicon chip is reported to demonstrate an all-optically tunable Fano resonance. In the device, an add-drop microring resonator (MRR) is employed, and one of the two bus waveguides is replaced by an FP cavity consisting of two sidewall Bragg gratings. By choosing the parameters of the gratings, the resonant mode of the FP cavity is coupled to one of the resonant modes of the MRR. Due to the coupling between the resonant modes, a Fano resonance with an asymmetric line shape resulted. Measurement results show a Fano resonance with an extinction ratio of 22.54 dB, and a slope rate of 250.4 dB/nm is achieved. A further study of the effect of the coupling on the Fano resonance is performed numerically and experimentally. Thanks to the strong light-confinement capacity of the MRR and the FP cavity, a strong two-photon absorption induced nonlinear thermal-optic effect resulted, which is used to tune the Fano resonance optically.

  7. Thermal radiation from optically driven Kerr (χ{sup (3)}) photonic cavities

    Energy Technology Data Exchange (ETDEWEB)

    Khandekar, Chinmay; Rodriguez, Alejandro W. [Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08540 (United States); Lin, Zin [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02139 (United States)

    2015-04-13

    We describe thermal radiation from nonlinear (χ{sup (3)}) photonic cavities coupled to external channels and subject to incident monochromatic light. Our work extends related work on nonlinear mechanical oscillators to the problem of thermal radiation, demonstrating that bistability can enhance thermal radiation by orders of magnitude and result in strong lineshape alternations, including “super-narrow spectral peaks” occurring at the onset of kinetic phase transitions. We show that when the cavities are designed to exhibit perfect linear emissivity (rate matching), such thermally activated transitions can be exploited to dramatically tune the output power and radiative properties of the cavity, leading to a kind of Kerr-mediated thermo-optic effect. Finally, we demonstrate that in certain parameter regimes, the output radiation exhibits Stokes and anti-Stokes side peaks whose relative magnitudes can be altered by tuning the internal temperature of the cavity relative to its surroundings, a consequence of strong correlations and interference between the emitted and reflected radiation.

  8. Non-intrusive tunable resonant microwave cavity for optical detected magnetic resonance of NV centres in nanodiamonds

    Science.gov (United States)

    Le Floch, Jean-Michel; Bradac, Carlo; Volz, Thomas; Tobar, Michael E.; Castelletto, Stefania

    2013-12-01

    Optically detected magnetic resonance (ODMR) in nanodiamond nitrogen-vacancy (NV) centres is usually achieved by applying a microwave field delivered by micron-size wires, strips or antennas directly positioned in very close proximity (~ μm) of the nanodiamond crystals. The microwave field couples evanescently with the ground state spin transition of the NV centre (2.87 GHz at zero magnetic field), which results in a reduction of the centre photoluminescence. We propose an alternative approach based on the construction of a dielectric resonator. We show that such a resonator allows for the efficient detection of NV spins in nanodiamonds without the constraints associated to the laborious positioning of the microwave antenna next to the nanodiamonds, providing therefore improved flexibility. The resonator is based on a tunable Transverse Electric Mode in a dielectric-loaded cavity, and we demonstrate that the resonator can detect single NV centre spins in nanodiamonds using less microwave power than alternative techniques in a non-intrusive manner. This method can achieve higher precision measurement of ODMR of paramagnetic defects spin transition in the micro to millimetre-wave frequency domain. Our approach would permit the tracking of NV centres in biological solutions rather than simply on the surface, which is desirable in light of the recently proposed applications of using nanodiamonds containing NV centres for spin labelling in biological systems with single spin and single particle resolution.

  9. Development of automatic impedance matching system for hyperthermia treatment using resonant cavity applicator.

    Science.gov (United States)

    Shindo, Y; Kato, K; Hirashima, T; Yabuhara, T

    2008-01-01

    In this paper, we discuss a new system to make impedance matching automatically for a re-entrant resonant cavity applicator for brain tumor hyperthermia treatment non-invasively. We have already discussed about the effectiveness of the heating method using manual type impedance matching controller, with experiments of heating an agar phantom and computer simulations. However, it becomes difficult to perform an accurate impedance matching as resonant frequency becomes high. Here, in order to make a more accurate impedance matching, we developed the automatic impedance matching system (AIMS). We noticed that the reflected power was generated when the impedance matching was not complete. In this system, therefore, to reduce the reflected power fed back, the stepping motor to turn the dial of variable capacitors is controlled by developed software. To evaluate the developed AIMS, the experiments of heating the agar phantom were performed. From these results, we found that the temperature rise of the agar phantom by using AIMS was about 180% of using manual type controller under the same heating condition. It was found that the proposed system was very effective for hyperthermia treatment using resonant cavity applicator even when the resonant frequency was high.

  10. Local thermal resonance control of GaInP photonic crystal membrane cavities using ambient gas cooling

    CERN Document Server

    Sokolov, Sergei; Yüce, Emre; Combrié, Sylvain; Lehoucq, Gaelle; De Rossi, Alfredo; Mosk, Allard P

    2015-01-01

    We perform a spatially dependent tuning of a GaInP photonic crystal cavity using a continuous wave violet laser. Local tuning is obtained by laser heating of the photonic crystal membrane. The cavity resonance shift is measured for different pump positions and for two ambient gases: helium and nitrogen. The use of high-conducting gas in combination with low-conducting semiconductor leads to a resonance control with a spatial resolution better than 4 microns.

  11. Study of Antenna Superstrates Using Metamaterials for Directivity Enhancement Based on Fabry-Perot Resonant Cavity

    Directory of Open Access Journals (Sweden)

    Haixia Liu

    2013-01-01

    Full Text Available Metamaterial superstrate is a significant method to obtain high directivity of one or a few antennas. In this paper, the characteristics of directivity enhancement using different metamaterial structures as antenna superstrates, such as electromagnetic bandgap (EBG structures, frequency selective surface (FSS, and left-handed material (LHM, are unifiedly studied by applying the theory of Fabry-Perot (F-P resonant cavity. Focusing on the analysis of reflection phase and magnitude of superstrates in presently proposed designs, the essential reason for high-directivity antenna with different superstrates can be revealed in terms of the F-P resonant theory. Furthermore, a new design of the optimum reflection coefficient of superstrates for the maximum antenna directivity is proposed and validated. The optimum location of the LHM superstrate which is based on a refractive lens model can be determined by the F-P resonant distance.

  12. Radiation emission from the "Rhodotron-TT200" cavity

    Institute of Scientific and Technical Information of China (English)

    Farshid Tabbakh; Mahmud Borhani

    2011-01-01

    In this paper, the X-rays emitted from the Rhodotron-TT200 cavity have been studied in depth.We found that the Bremsstrahlung interaction is the only contribution of X-ray generation important to safety.The X-ray dose rate in the Rhodotron vault is calculated for normal conditions based on MCNP4C results.The presented calculation shows good agreement with the experimental measurements, which consequently confirms the reliability of the calculation for use in shielding design and other safety aspects.

  13. Folded-Cavity Resonators as Key Elements for Optical Filtering and Low-Voltage Electroabsorption Modulation

    Science.gov (United States)

    Djordjev, Kostadin D.; Lin, Chao-Kun; Zhu, Jintian; Bour, David; Tan, Michael R.

    2006-09-01

    Folded-cavity (FC) resonators, which are based on shallow-etched ridge waveguides combined with four deeply etched turning mirrors, are designed and fabricated. The device consists of a resonant FC and a bus waveguide coupled to it through a directional coupler. Optical passive filters, based on this technology, exhibit quality factors in the excess of 5000, with a low insertion loss of 5 dB (including the input coupling loss to a fiber) and more than 15-dB extinction at resonance. When the filter is combined with an electroabsorption active region and is designed to operate in the overcoupled regime, a low-voltage/high-extinction-ratio resonant modulation becomes feasible. The resonant modulator exhibits a low insertion loss (greater than 22-dB extinction at resonance) and offers a low-voltage operation. A change in the applied voltage by 0.7 V (close to the critically coupled conditions) leads to a transmission change of more than 16 dB. Open eye diagrams at 12 Gb/s are presented. To decrease the insertion loss, multiple material bangaps are further monolithically integrated across the wafer by utilizing the quantum-well-intermixing techniques.

  14. 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)

  15. Dual-wavelength distributed Bragg reflector semiconductor laser based on a composite resonant cavity

    Science.gov (United States)

    Chen, Cheng; Zhao, Ling-Juan; Qiu, Ji-Fang; Liu, Yang; Wang, Wei; Lou, Cai-Yun

    2012-09-01

    We report a monolithic integrated dual-wavelength laser diode based on a distributed Bragg reflector (DBR) composite resonant cavity. The device consists of three sections, a DBR grating section, a passive phase section, and an active gain section. The gain section facet is cleaved to work as a laser cavity mirror. The other laser mirror is the DBR grating, which also functions as a wavelength filter and can control the number of wavelengths involved in the laser action. The reflection bandwidth of the DBR grating is fabricated to have an appropriate value to make the device work at the dual-wavelength lasing state. We adopt the quantum well intermixing (QWI) technique to provide low-absorption loss grating and passive phase section in the fabrication process. By tuning the injection currents on the DBR and the gain sections, the device can generate 0.596 nm-spaced dual-wavelength lasing at room temperature.

  16. Surface-Plasmon-Polariton Laser based on an Open-Cavity Fabry-Perot Resonator

    CERN Document Server

    Zhu, Wenqi; Agrawal, Amit; Lezec, Henri J

    2016-01-01

    Recent years have witnessed growing interest in the development of small-footprint lasers for potential applications in small-volume sensing and on-chip optical communications. Surface-plasmons, electromagnetic modes evanescently confined to metal-dielectric interfaces, offer an effective route to achieving lasing at nanometer-scale dimensions when resonantly amplified in contact with a gain-medium. Here, we achieve visible frequency ultra-narrow linewidth lasing at room-temperature by leveraging surface plasmons propagating in an open Fabry-Perot cavity formed by a flat metal surface coated with a subwavelength-thick layer of optically-pumped gain medium and orthogonally bound by a pair of flat metal sidewalls. Low perturbation transmission-configuration sampling of the lasing plasmon mode is achieved via an evanescently coupled recessed nanoslit, opening the way to high-figure-of-merit refractive-index sensing of analytes interacting with the open cavity.

  17. Micro-ring resonator quality factor enhancement via an integrated Fabry-Perot cavity

    Directory of Open Access Journals (Sweden)

    Jiayang Wu

    2017-05-01

    Full Text Available We propose and experimentally demonstrate 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. By utilizing 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 significantly improved. The device is theoretically analyzed and practically fabricated on a silicon-on-insulator wafer. Experimental results show that up to 11-times improvement in the Q factor, together with an 8-dB increase in the ER, can be achieved via our proposed method. The impact of varying structural parameters on the device performance is also investigated and verified by the measured spectra of the fabricated devices with different structural parameters.

  18. Parametric generation of radiation in a dynamic cavity with frequency dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Rosanov, N N; Fedorov, E G; Matskovsky, A A [Federal State Unitary Enterprise ' Scientific and Industrial Corporation ' Vavilov State Optical Institute' , St. Petersburg (Russian Federation)

    2016-01-31

    A numerical simulation of the parametric generation of electromagnetic radiation in a cavity with periodically oscillating mirrors and Lorentz-type frequency dispersion has been performed. It is shown that initially weak seed radiation can be transformed into intense short pulses, the shape of which under steady-state conditions changes periodically when reflecting from mirrors and, depending on the dispersion characteristics, corresponds to uni- or bipolar pulses. (letters)

  19. Semi-random simulation method for calculating 3-D radiation transfer problems in cavity

    Institute of Scientific and Technical Information of China (English)

    冯庭桂; 赖东显

    1996-01-01

    One of the most important issues in inertial confinement fusion (ICF) is to study the uniformity of the radiation field around the implosion pellet containing fuel.To this end,a numerical method linking Monte Carlo with iteration method is presented for calculating the radiation transfer problems in a cavity.The detail of the calculation scheme is described and some numerical examples are also given.

  20. Plasmonic Metasurfaces Based on Nanopin-Cavity Resonator for Quantitative Colorimetric Ricin Sensing.

    Science.gov (United States)

    Fan, Jiao-Rong; Zhu, Jia; Wu, Wen-Gang; Huang, Yun

    2017-01-01

    In view of the toxic potential of a bioweapon threat, rapid visual recognition and sensing of ricin has been of considerable interest while remaining a challenging task up to date. In this study, a gold nanopin-based colorimetric sensor is developed realizing a multicolor variation for ricin qualitative recognition and analysis. It is revealed that such plasmonic metasurfaces based on nanopin-cavity resonator exhibit reflective color appearance, due to the excitation of standing-wave resonances of narrow bandwidth in visible region. This clear color variation is a consequence of the reflective color mixing defined by different resonant wavelengths. In addition, the colored metasurfaces appear sharp color difference in a narrow refractive index range, which makes them especially well-suited for sensing applications. Therefore, this antibody-functionalized nanopin-cavity biosensor features high sensitivity and fast response, allowing for visual quantitative ricin detection within the range of 10-120 ng mL(-1) (0.15 × 10(-9) -1.8 × 10(-9) m), a limit of detection of 10 ng mL(-1) , and the typical measurement time of less than 10 min. The on-chip integration of such nanopin metasurfaces to portable colorimetric microfluidic device may be envisaged for the quantitative studies of a variety of biochemical molecules.

  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. Electron cyclotron resonance ion source plasma chamber studies using a network analyzer as a loaded cavity probe

    Energy Technology Data Exchange (ETDEWEB)

    Toivanen, V.; Tarvainen, O.; Kauppinen, J.; Komppula, J.; Koivisto, H. [Department of Physics, University of Jyvaeskylae, Jyvaeskylae 40500 (Finland); Lyneis, C. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2012-02-15

    A method and first results utilizing a network analyzer as a loaded cavity probe to study the resonance properties of a plasma filled electron cyclotron resonance ion source (ECRIS) plasma chamber are presented. The loaded cavity measurements have been performed using a dual port technique, in which two separate waveguides were used simultaneously. One port was used to ignite and sustain the plasma with a microwave source operating around 11 GHz and the other was used to probe the cavity properties with the network analyzer using a frequency range around 14 GHz. The first results obtained with the JYFL 14 GHz ECRIS demonstrate that the presence of plasma has significant effects on the resonance properties of the cavity. With plasma the frequency dependent behavior is strongly damped and this trend strengthens with increasing microwave power.

  3. Double-cavity radiometer for high-flux density solar radiation measurements.

    Science.gov (United States)

    Parretta, A; Antonini, A; Armani, M; Nenna, G; Flaminio, G; Pellegrino, M

    2007-04-20

    A radiometric method has been developed, suitable for both total power and flux density profile measurement of concentrated solar radiation. The high-flux density radiation is collected by a first optical cavity, integrated, and driven to a second optical cavity, where, attenuated, it is measured by a conventional radiometer operating under a stationary irradiation regime. The attenuation factor is regulated by properly selecting the aperture areas in the two cavities. The radiometer has been calibrated by a pulsed solar simulator at concentration levels of hundreds of suns. An optical model and a ray-tracing study have also been developed and validated, by which the potentialities of the radiometer have been largely explored.

  4. Outflows in massive star forming regions: UV radiation and shocked cavity walls toward AFGL 2591

    Science.gov (United States)

    Doty, Steven; Rogers, Noah; Doty, Sandra; van der Tak, Floris; van Dishoeck, Ewine

    2015-08-01

    Outflows can play an important role in regulating the star formation process. These outflows have the potential to deposit significant energy to large distances from the protostar through material motion and shocks, as well as via radiation through the subsequent outflow cavity. Herschel observations of high-J CO lines toward massive star-forming regions such as AFGL 2591 show line strengths that appear to be inconsistent with a spherical envelope. Following recent work on low-mass star forming regions, we construct a model whereby the excited molecular line emission originates in a shocked + UV irradiated outflow cavity wall. The validity of the cavity wall model in this context is considered. The observational data are then used to constrain the model, including the type of shocks, and relative strength of shocks versus radiation.

  5. Influence of radiation on double conjugate diffusion in a porous cavity

    Energy Technology Data Exchange (ETDEWEB)

    Azeem,; Idris, Mohd Yamani Idna [Dept. of Computer System & Technology, University of Malaya, Kuala Lumpur (Malaysia); Khan, T. M. Yunus, E-mail: yunus.tatagar@gmail.com [Dept. of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603 (Malaysia); Dept. of Mechanical Engineering, BVB College of Engineering & Technology, Hubli (India); Badruddin, Irfan Anjum, E-mail: irfan-magami@Rediffmail.com; Nik-Ghazali, N. [Dept. of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603 (Malaysia)

    2016-05-06

    The current work highlights the effect of radiation on the conjugate heat and mass transfer in a square porous cavity having a solid wall. The solid wall is placed at the center of cavity. The left surface of cavity is maintained at higher temperature T{sub w} and concentration C{sub w} whereas the right surface is maintained at T{sub c} and C{sub c} such that T{sub w}>T{sub c} and Cw>Cc. The top and bottom surfaces are adiabatic. The governing equations are solved with the help of finite element method by making use of triangular elements. The results are discussed with respect to two different heights of solid wall inside the porous medium along with the radiation parameter.

  6. Studies of radiation fields of LCLS-II super conducting radio frequency cavities

    Science.gov (United States)

    Santana Leitner, M.; Ge, L.; Li, Z.; Xu, C.; Adolphsen, C.; Ross, M.; Carrasco, M.

    2016-09-01

    The Linac Coherent Light Source II (LCLS-II) will be a hard X-ray Free Electron Laser whose linac can deliver a 1.2 MW CW electron beam with bunch rates up to 1 MHz. To efficiently generate such a high power beam, Super-Conducting Radio-Frequency (SCRF) cavities will be installed in the upstream portion of the existing 3 km Linac at the SLAC National Accelerator Laboratory. The 9-cell niobium cavities will be cooled at 2K inside 35 cryomodules, each containing a string of eight of those cavities followed by a quadrupole. The strong electromagnetic fields in the SCRF cavities will extract electrons from the cavity walls that may be accelerated. Most such dark current will be deposited locally, although some electrons may reach several neighboring cryomodules, gaining substantial energy before they hit a collimator or other aperture. The power deposited by the field emitted electrons and the associated showers may pose radiation and machine protection issues at the cryomodules and also in other areas of the accelerator. Simulation of these effects is therefore crucial for the design of the machine. The in-house code Track3P was used to simulate field emitted electrons from the LCLS-II cavities, and a sophisticated 3D model of the cryomodules including all cavities was written to transport radiation with the Fluka Monte Carlo code, which was linked to Track3P through custom-made routines. This setup was used to compute power deposition in components, prompt and residual radiation fields, and radioisotope inventories.

  7. Outflows in massive star forming regions: UV radiation and shocked cavity walls toward AFGL 2591

    NARCIS (Netherlands)

    Doty, Steven; Rogers, Noah; Doty, Sandra; van der Tak, Floris; van Dishoeck, Ewine

    2015-01-01

    Outflows can play an important role in regulating the star formation process. These outflows have the potential to deposit significant energy to large distances from the protostar through material motion and shocks, as well as via radiation through the subsequent outflow cavity. Herschel observation

  8. Mitigation of radiation-pressure-induced angular instability of a Fabry–Perot cavity consisting of suspended mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Nagano, Koji, E-mail: knagano@icrr.u-tokyo.ac.jp [KAGRA Observatory, Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Enomoto, Yutaro; Nakano, Masayuki [KAGRA Observatory, Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Kawamura, Seiji [KAGRA Observatory, Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan)

    2016-12-01

    To observe radiation pressure noise in optical cavities consisting of suspended mirrors, high laser power is necessary. However, because the radiation pressure on the mirrors could cause an angular anti-spring effect, the high laser power could induce angular instability to the cavity. An angular control system using radiation pressure as an actuator, which was previously invented to reduce the anti-spring effect for the low power case, was applied to the higher power case where the angular instability would occur. As a result the angular instability was mitigated. It was also demonstrated that the cavity was unstable without this control system. - Highlights: • High laser power could cause angular instability to a suspended Fabry–Perot cavity. • To mitigate the instability, the control system using radiation pressure is applied. • Mitigating the radiation-pressure-induced angular instability is demonstrated. • It is also confirmed that the cavity would be unstable without the control system.

  9. 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.

  10. 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.

  11. 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.

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

    CERN Document Server

    Karhu, J; Vainio, M; Metsälä, 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 populate an intermediate vibrational state. High output power of the optical parametric oscillator and the strength of the mid-infrared transition result in efficient population transfer to the intermediate state, which allows measuring secondary transitions from this state with a high signal-to-noise ratio. A secondary, near-infrared transition from the intermediate state is probed using cavity ring down spectroscopy, which provides high sensitivity in this wavelength region. Due to the narrow linewidths of the excitation sources, the rovibrational lines of the secondary transition are measured with sub-Doppler resolution. The setup is used to access a previously unreported symmetric vibrational state of acetylene, $\

  13. Color-Tunable Resonant Photoluminescence and Cavity-Mediated Multistep Energy Transfer Cascade.

    Science.gov (United States)

    Okada, Daichi; Nakamura, Takashi; Braam, Daniel; Dao, Thang Duy; Ishii, Satoshi; Nagao, Tadaaki; Lorke, Axel; Nabeshima, Tatsuya; Yamamoto, Yohei

    2016-07-26

    Color-tunable resonant photoluminescence (PL) was attained from polystyrene microspheres doped with a single polymorphic fluorescent dye, boron-dipyrrin (BODIPY) 1. The color of the resonant PL depends on the assembling morphology of 1 in the microspheres, which can be selectively controlled from green to red by the initial concentration of 1 in the preparation process of the microspheres. Studies on intersphere PL propagation with multicoupled microspheres, prepared by micromanipulation technique, revealed that multistep photon transfer takes place through the microspheres, accompanying energy transfer cascade with stepwise PL color change. The intersphere energy transfer cascade is direction selective, where energy donor-to-acceptor down conversion direction is only allowed. Such cavity-mediated long-distance and multistep energy transfer will be advantageous for polymer photonics device application.

  14. Fano resonances in antennas: General control over radiation patterns

    CERN Document Server

    Rybin, Mikhail V; Filonov, Dmitry S; Slobozhanyuk, Alexey P; Belov, Pavel A; Kivshar, Yuri S; Limonov, Mikhail F

    2013-01-01

    The concepts of many optical devices are based on the fundamental physical phenomena such as resonances. One of the commonly used devices is an electromagnetic antenna that converts localized energy into freely propagating radiation and vise versa, offering unique capabilities for controlling electromagnetic radiation. Here we propose a concept for controlling the intensity and directionality of electromagnetic wave scattering in radio-frequency and optical antennas based on the physics of Fano resonances. We develop an analytical theory of spatial Fano resonances in antennas that describes switching of the radiation pattern between the forward and backward directions, and confirm our theory with both numerical calculations and microwave experiments. Our approach bridges the concepts of conventional radio antennas and photonic nanoantennas, and it provides a paradigm for the design of wireless optical devices with various functionalities and architectures.

  15. Sensitivity of surface resistance measurement of HTS thin films by cavity resonator, dielectric resonator and microstrip line resonator

    Indian Academy of Sciences (India)

    N D Kataria; Mukul Misra; R Pinto

    2002-05-01

    Microwave surface resistance s of silver-doped YBa2Cu3O7- (YBCO) thin film, deposited by laser ablation technique on 10 mm × 10 mm LaAlO3 substrate, has been measured by resonant techniques in the frequency range from 5 GHz to 20 GHz. The geometrical factor of the sample and the resonator has been determined theoretically by the knowledge of the electromagnetic field distribution in the resonators. The microwave surface resistance of the superconducting sample is then extracted from the measured value as a function of temperature. The sensitivity of the s measurement, that is, the relative change in the value with the change in the s value is determined for each resonator.

  16. Resonance features of coupled Josephson junctions: radiation and shunting

    Science.gov (United States)

    Shukrinov, Yu M.; Seidel, P.; Il'ichev, E.; Nawrocki, W.; Grajcar, M.; Plecenik, P. A.; Rahmonov, I. R.; Kulikov, K.

    2012-11-01

    We study the phase dynamics and the resonance features of coupled Josephson junctions in layered superconductors and their manifestations in the current- voltage characteristics and temporal dependence of the electric charge in the superconducting layers. Results on the effect of the external radiation and shunting of the stack of Josephson junctions by LC-elements are presented. We discuss the ideas concerning the experimental observation of these resonances.

  17. Influence of low-intensity laser radiation upon the microflora of carious cavities and root canal

    Science.gov (United States)

    Shumilovitch, Bogdan R.; Nekrylov, Valery; Mazo, Leonid

    1995-04-01

    Laser stomatology- a relatively young branch of stomatology -has been developing actively lately. Bactericidal action of laser radiation enables to use it widely for processing carious cavities and root canals in the treatment of caries and its complications. 113 patients were studied by us. The 40 patients had antiseptic procedure of the caries cavity and then the procedure of laser therapy, so micro-organisms were found out in 26% cases. The 63 patients had antiseptic procedure only, so micro-organisms were found out in 70% cases. Control group were consisted of patients, where laser therapy was carried out without antiseptic remedies.

  18. Lithium-argon discharges in a multicusp-ECR microwave resonant cavity

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, C.B.; Brake, M.L. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering

    1995-12-01

    A newly designed multicusp-ECR microwave resonant cavity is being used as a lithium plasma source. Lithium plasma sources have a variety of applications in nuclear fusion research. As a source of ions or neutrals for beams, they are utilized in diagnostics and fueling of magnetic confinement fusion. Argon and lithium-argon discharges have been created in a multicusp-ECR microwave resonant cavity. A double Langmuir probe has been used to determine discharge characteristics, indicating ion densities of 10{sup 10}--10{sup 11} cm{sup {minus}3} and electron temperatures of about 3 eV with operating pressures of 4--20 mtorr and input powers of 100--250 W. Lithium is introduced to the system in the form of lithium chloride or lithium carbonate which is then heated by a background argon discharge allowing dissociation of lithium. The dissociation is evidenced by the observation of strong Li-I lines in the discharge using optical emission spectroscopy. LiCl was found to give a strong Li-I optical signal for about 15 min run time whereas Li{sub 2}CO{sub 3} gave lower intensity lines, but for about 60 min run time.

  19. Circuit-tunable sub-wavelength THz resonators: hybridizing optical cavities and loop antennas.

    Science.gov (United States)

    Paulillo, B; Manceau, J M; Degiron, A; Zerounian, N; Beaudoin, G; Sagnes, I; Colombelli, R

    2014-09-08

    We demonstrate subwavelength electromagnetic resonators operating in the THz spectral range, whose spectral properties and spatial/angular patterns can be engineered in a similar way to an electronic circuit. We discuss the device concept, and we experimentally study the tuning of the resonant frequency as a function of variable capacitances and inductances. We then elucidate the optical coupling properties. The radiation pattern, obtained by angle-resolved reflectance, reveals that the system mainly couples to the outside world via a magnetic dipolar interaction.

  20. Shielding effectiveness of rectangular cavity made of a new shielding material and resonance suppression

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    New shielding material has become an alternative to traditional metal to shield boxes from electromagnetic interferences. This article introduces the theory of transmission line method to study the shield boxes made of a new sort of material, and then expands the fundamental formulas to deal with the cases of multiple holes and polarization with arbitrary angle. By means of genetic algorithms with the aid of a three dimensional simulation tool, the damping of electromagnetic resonances in enclosures is researched.The computation indicates that under resonant frequency, electromagnetic resonance results in low, even negative shielding coefficient; whereas, for the same areas, shielding effectiveness of a single hole is worse than that of multiple holes. Shielding coefficient varies when polarization angle increases, and the coupled field through the rectangular aperture with the long side parallel to the thin wire is much weaker than that with the long side vertical to the thin wire. By using the metallic-loss dielectric layer of optimized calculation on the internal surface of the cavity, the best result of resonance suppression has been realized with the same thickness of coating. Finally, according to the calculation result, suggestions for shielding are proposed.

  1. Tunable sub-gap radiation detection with superconducting resonators

    Science.gov (United States)

    Dupré, O.; Benoît, A.; Calvo, M.; Catalano, A.; Goupy, J.; Hoarau, C.; Klein, T.; Le Calvez, K.; Sacépé, B.; Monfardini, A.; Levy-Bertrand, F.

    2017-04-01

    We have fabricated planar amorphous indium oxide superconducting resonators ({T}{{c}}∼ 2.8 K) that are sensitive to frequency-selective radiation in the range of 7–10 GHz. Those values lay far below twice the superconducting gap that is worth about 200 GHz. The photon detection consists in a shift of the fundamental resonance frequency. We show that the detected frequency can be adjusted by modulating the total length of the superconducting resonator. We attribute those observations to the excitation of higher-order resonance modes. The coupling between the fundamental lumped and the higher order distributed resonance is due to the kinetic inductance nonlinearity with current. These devices, that we have called sub-gap kinetic inductance detectors, are to be distinguished from the standard kinetic inductance detectors in which quasi-particles are generated when incident light breaks down Cooper pairs.

  2. Designing and Dosimetry of a Shield for Photon Fields of Radiation Therapy in Oral Cavity Cancer

    Science.gov (United States)

    Jabbari, Keyvan; Senobari, Somayeh; Roayaei, Mahnaz; Rostampour, Masoumeh

    2015-01-01

    The cancer of oral cavity is related to lesions of mucous membrane of tongue and gum that can be treated with radiation therapy. A lateral photon field can be used to treat this kind of tumor, which has a side-effect on normal tissue in the opposite side of the oral cavity. In this study the dosimetric effect of the various shields in oral cavity is evaluated. In this study, a special phantom similar to the structure of oral cavity with capability of film dosimetry was designed and constructed. The various shield slabs were made of five materials: Lead, Plexiglas, Acrylic resin, Silicon and Plaster. For irradiation, Cobalt 60 (60Co) and 6 MV photon beams were used. The film dosimetry before and after the shield was performed using GAFCHROMIC EBT2 films. The film before the shield measures the magnitude of backscattering radiation from the shield. The prescribed dose was 150 cGy. Results showed that 3 cm of the lead in both energies had the maximum absorption of radiation. The absorbed dose to opposite side of shield for 6 MV photon beams and 60Co were 21 and 32 cGy, respectively. The minimum attenuation on radiation was observed in silicon shield for which the dose of opposite side were 116 and 147 cGy for 6 MV and 60Co respectively. The maximum backscattered dose was measured 177 cGy and 219 cGy using 3 cm thickness of lead, which was quite considerable. The minimum backscattering where for acrylic resin 101 and 118 cGy for 6 MV and cobalt. In this study, it was concluded that the amount of backscattering for 3 cm Lead shield is quite considerable and increases the dose significantly. A composite layer of shield with 1–2 cm lead and 1 cm acrylic resin can have the protective effect and low backscattering radiation at the same time. PMID:26120570

  3. Doubly-Resonant Fabry-Perot Cavity for Power Enhancement of Burst-Mode Picosecond Ultraviolet Pulses

    Energy Technology Data Exchange (ETDEWEB)

    Abudureyimu, Reheman [ORNL; Huang, Chunning [ORNL; Liu, Yun [ORNL

    2015-01-01

    We report on a first experimental demonstration of locking a doubly-resonant Fabry-Perot cavity to burst-mode picosecond ultraviolet (UV) pulses by using a temperature controlled dispersion compensation method. This technique will eventually enable the intra cavity power enhancement of burst-mode 402.5MHz/50ps UV laser pulses with a MW level peak power required for the laser assisted H- beam stripping experiment at the Spallation Neutron Source.

  4. Power generation in a resonant cavity using a beam bunched at 35 GHz by a free electron laser

    Science.gov (United States)

    Donohue, J. T.; Gardelle, J.; Lefevre, T.; Rullier, J. L.; Vermare, C.; Lidia, S. M.; Meurdesoif, Y.

    2000-05-01

    An intense beam of relativistic electrons (800 A, 6.7 MeV) has been bunched at 35 GHz by a free-electron laser, in which output power levels exceeding 100 MW were obtained. The beam was then extracted and transported through a resonant cavity, that was excited by its passage. Microwave power levels of 10 MW were extracted from the cavity, in reasonable agreement with a simple formula which relates power output to known properties of the both beam and cavity.

  5. Influence of left-handed material on the resonant frequency of resonant cavity%左手介质对谐振腔谐振频率的影响∗

    Institute of Scientific and Technical Information of China (English)

    李培; 王辅忠; 张丽珠; 张光璐

    2015-01-01

    The quality factor and the resonant frequency of a resonant cavity are the key factors that need to be considered in the process of resonator design. The wall of cavity is composed of conductor materials which are effective tools to generate high-frequency oscillation. The microwave cavity is widely used. From the perspective of the circuit, it has almost all the properties of LC resonance unit, such as mode selection. Therefore, it is widely used in filters, matching circuits, and antenna design. In industrial applications, the demand for high-frequency resonant cavity is relatively large. A traditional method can increase the resonant frequency of the resonant cavity by reducing the size of the cavity or using the high-order modes. However, as both approaches have their limitations, the design results are not ideal. By combining theoretical calculation and simulation, the factors that affect the resonant frequency of the resonator are analyzed. The results show the relationship between material properties of the filling medium and the resonant frequency of the cavity. Theoretical calculations show that when the left-handed materials are used as filling materials in the cavity, the resonant frequency can be increased without changing the size of the cavity. The results of high frequency structure simulator also prove the above result. Therefore, the resonant frequency of the resonator cannot be limited by the cavity size. It can be seen from the data that compared with reducing the size of the resonator or using high-order modes, filling left-handed materials can improve resonant frequency to a greater extent. The obtained conclusion shows a further progress compared with the traditional theory and provides a theoretical basis for the exploration and design of novel resonators.

  6. Resonance Raman Spectroscopy of Free Radicals Produced by Ionizing Radiation

    DEFF Research Database (Denmark)

    Wilbrandt, Robert Walter

    1984-01-01

    Applications of time-resolved resonance Raman spectroscopy to the study of short-lived free radicals produced by ionizing radiation are briefly reviewed. Potential advantages and limitations of this technique are discussed in the light of given examples. The reduction of p-nitrobenzylchloride and......Applications of time-resolved resonance Raman spectroscopy to the study of short-lived free radicals produced by ionizing radiation are briefly reviewed. Potential advantages and limitations of this technique are discussed in the light of given examples. The reduction of p......-nitrobenzylchloride and subsequent formation of the p-nitrobenzyl radical and the reaction of p-nitrotoluene with O– are studied by resonance Raman and optical absorption spectroscopy....

  7. Design of a Novel Polarized Beam Splitter Based on a Two-Dimensional Photonic Crystal Resonator Cavity

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xuan; CHEN Shu-Wen; LIAO Qing-Hua; YU Tian-Bao; LIU Nian-Hua; HUANG Yong-Zhen

    2011-01-01

    @@ We propose and analyze a novel ultra-compact polarization beam splitter based on a resonator cavity in a two-dimensional photonic crystal.The two polarizations can be separated efficientlyby the strong coupling between the microcavities and the waveguides occurring around the resonant frequency of the cavities.The transmittance of two polarized light around 1.55 iim can be more than 98.6%, and the size of the device is less than 15 μm x 13μm,so these features will play an important role in future integrated optical circuits.

  8. Radiation therapy of the oral cavity: sequelae and management. Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Beumer, J. III; Curtis, T.; Harrison, R.E.

    1979-03-01

    This is the first article in a two-part series dealing with the effects and manifestations in the oral cavity of radiation therapy of head and neck tumors. In this section, oral mucous membranes, taste buds, edema and trismus, diet, salivary glands, bone, peridontium, teeth, and composition of oral flora are discussed. Dental management of the dentulous patient is then approached; criteria for preradiation extraction are delineated.

  9. Modulating resonance modes and Q value of a CdS nanowire cavity by single Ag nanoparticles.

    Science.gov (United States)

    Zhang, Qing; Shan, Xin-Yan; Feng, Xiao; Wang, Chun-Xiao; Wang, Qu-Quan; Jia, Jin-Feng; Xue, Qi-Kun

    2011-10-12

    Semiconductor nanowire (NW) cavities with tailorable optical modes have been used to develop nanoscale oscillators and amplifiers in microlasers, sensors, and single photon emitters. The resonance modes of NW could be tuned by different boundary conditions. However, continuously and reversibly adjusting resonance modes and improving Q-factor of the cavity remain a great challenge. We report a method to modulate resonance modes continuously and reversibly and improve Q-factor based on surface plasmon-exciton interaction. By placing single Ag nanoparticle (NP) nearby a CdS NW, we show that the wavelength and relative intensity of the resonance modes in the NW cavity can systematically be tuned by adjusting the relative position of the Ag NP. We further demonstrate that a 56% enhancement of Q-factor and an equivalent π-phase shift of the resonance modes can be achieved when the Ag NP is located near the NW end. This hybrid cavity has potential applications in active plasmonic and photonic nanodevices.

  10. Cavity-controlled radiative recombination of excitons in thin-film solar cells

    OpenAIRE

    Vuong, Luat T.; Kozyreff, Gregory; Betancur; Martorell, Jordi

    2009-01-01

    The following article appeared in Vuong, Luat T. ...[et al.]. Cavity-controlled radiative recombination of excitons in thin-film solar cells. Applied physics letters [en línia]. 2009, vol. 95 [Consulta 29/06/2010]. p. 233106-1/233106-3 and may be found at http://apl.aip.org/applab/v95/i23/p233107_s1?view=fulltext We study the performance of photovoltaic devices when controlling the exciton radiative recombination time. We demonstrate that when high-quantum-yield fluorescent photovoltaic ma...

  11. Free convection in a square cavity filled by a porous medium saturated by a nanofluid: Viscous dissipation and radiation effects

    OpenAIRE

    M. Ghalambaz; M. Sabour; Pop, I.

    2016-01-01

    The influence of the viscous dissipation and radiation effects on the natural convection heat transfer in a square cavity filled with porous media saturated with a nanofluid is studied. The vertical walls of the cavity are subject to finite temperature difference while the top and bottom walls of the cavity are insulated. The Buongiorno's nanofluid model, incorporating the Brownian motion and thermophoresis effects, is employed. The governing equations, in nondimensional form, are written in ...

  12. Development of a cryogenic radiation detector for mapping radio frequency superconducting cavity field emissions

    Energy Technology Data Exchange (ETDEWEB)

    Danny Dotson; John Mammosser

    2005-05-01

    Field emissions in a super conducting helium cooled RF cavity and the production of radiation (mostly X-Rays) have been measured externally on cryomodules at Jefferson Lab since 1991. External measurements are limited to radiation energies above 100 keV due to shielding of the stainless steel cryogenic body. To measure the onset of and to map field emissions from a superconducting cavity requires the detecting instrument be inside the shield and within the liquid Helium. Two possible measurement systems are undergoing testing at JLab. A CsI detector array set on photodiodes and an X-Ray film camera with a fixed aperture. Several devices were tested in the cell with liquid Helium without success. The lone survivor, a CsI array, worked but saturated at high power levels due to backscatter. The array was encased in a lead shield with a slit opening set to measure the radiation emitted directly from the cell eliminating a large portion of the backscatter. This is a work in progress and te sting should be complete before the PAC 05. The second system being tested is passive. It is a shielded box with an aperture to expose radiation diagnostic film located inside to direct radiation from the cell. Developing a technique for mapping field emissions in cryogenic cells will assist scientists and engineers in pinpointing any surface imperfections for examination.

  13. Cavity ring-up spectroscopy for dissipative and dispersive sensing in a whispering gallery mode resonator

    CERN Document Server

    Yang, Yong; Kasumie, Sho; Ward, Jonathan M; Chormaic, Síle Nic

    2016-01-01

    In whispering gallery mode resonator sensing applications, the conventional way to detect a change in the parameter to be measured is by observing the steady state transmission spectrum through the coupling waveguide. Alternatively, cavity ring-up spectroscopy (CRUS) sensing can be achieved transiently. In this work, we investigate CRUS using coupled mode equations and find analytical solutions with a large spectral broadening approximation of the input pulse. The relationships between the frequency detuning, coupling gap and ring-up peak height are determined and experimentally verified using an ultrahigh \\textit{Q}-factor silica microsphere. This work shows that distinctive dispersive and dissipative transient sensing can be realised by simply measuring the peak height of the CRUS signal, which might improve the data collection rate.

  14. 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.

  15. Cavity-aided magnetic-resonance microscopy of atoms in optical lattices

    CERN Document Server

    Purdy, Tom P; Brooks, Daniel W C; Botter, Thierry; Stamper-Kurn, Dan M

    2010-01-01

    Magnetic resonance imaging (MRI) is a powerful technique for investigating the microscopic properties and dynamics of physical systems. In this work we demonstrate state-sensitive MRI of ultracold atoms in an optical lattice. Single-shot spatial resolution is 120 nm, well below the lattice spacing, and number sensitivity is +/-2.4 for 150 atoms on a single site, well below Poissonian atom-number fluctuations. We achieve this by combining high-spatial-resolution control over the atomic spin using an atom chip, together with nearly quantum-limited spin measurement, obtained by dispersively coupling the atoms to light in a high-finesse optical cavity. The MRI is minimally disruptive of the atoms' internal state, preserving the magnetisation of the gas for subsequent experiments. Using this technique, we observe the nonequilibrium transport dynamics of the atoms among individual lattice sites. We see the atom cloud initially expand ballistically, followed by the onset of interaction-inhibited transport.

  16. Reply to "Comment on `Normalization of quasinormal modes in leaky optical cavities and plasmonic resonators' "

    Science.gov (United States)

    Kristensen, Philip Trøst; Ge, Rong-Chun; Hughes, Stephen

    2017-07-01

    We refute all claims of the "Comment on `Normalization of quasinormal modes in leaky optical cavities and plasmonic resonators' " by E. A. Muljarov and W. Langbein. Based entirely on information already contained in our original article [P. T. Kristensen, R.-C. Ge, and S. Hughes, Phys. Rev. A 92, 053810 (2015), 10.1103/PhysRevA.92.053810], we dismiss every point of criticism as being unsupported and point out how important parts of our argumentation appear to have been overlooked by the Comment authors. In addition, we provide additional calculations showing directly the connection between the normalizations by Sauvan et al. and Muljarov et al., which were not included in our original article.

  17. 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.

  18. High-quality distributed Bragg reflectors for resonant-cavity light-emitting diode applications

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, S.; Naranjo, F.B.; Calle, F.; Sanchez-Garcia, M.A.; Calleja, E. [ISOM, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Departamento de Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Vennegues, P. [CHREA-CNRS, Rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France)

    2002-08-16

    Efficient distributed Bragg reflectors based on Al{sub x}Ga{sub 1} {sub -} {sub x}N/GaN multilayer stacks have been grown by plasma-assisted molecular-beam epitaxy on GaN/Al{sub 2}O{sub 3} templates. The final goal is to incorporate these reflectors as bottom mirrors in a backside (sapphire) resonant-cavity light-emitting diode at 510 nm. The reflectors have been characterised by atomic force microscopy, high-resolution X-ray diffraction and high-resolution transmission electron microscopy. Reflectivity measurements have also been performed, obtaining values between 30% and 50%, depending on the Al content used. The incorporation of the Al{sub x}Ga{sub 1} {sub -} {sub x}N/GaN Bragg reflector as bottom mirror in a RCLED structure improves the output power by a factor of 12 compared with conventional light-emitting diodes. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  19. Microcontroller based resonance tracking unit for time resolved continuous wave cavity-ringdown spectroscopy measurements.

    Science.gov (United States)

    Votava, Ondrej; Mašát, Milan; Parker, Alexander E; Jain, Chaithania; Fittschen, Christa

    2012-04-01

    We present in this work a new tracking servoloop electronics for continuous wave cavity-ringdown absorption spectroscopy (cw-CRDS) and its application to time resolved cw-CRDS measurements by coupling the system with a pulsed laser photolysis set-up. The tracking unit significantly increases the repetition rate of the CRDS events and thus improves effective time resolution (and/or the signal-to-noise ratio) in kinetics studies with cw-CRDS in given data acquisition time. The tracking servoloop uses novel strategy to track the cavity resonances that result in a fast relocking (few ms) after the loss of tracking due to an external disturbance. The microcontroller based design is highly flexible and thus advanced tracking strategies are easy to implement by the firmware modification without the need to modify the hardware. We believe that the performance of many existing cw-CRDS experiments, not only time-resolved, can be improved with such tracking unit without any additional modification to the experiment. © 2012 American Institute of Physics

  20. Three-dimensional FDTD Modeling of Earth-ionosphere Cavity Resonances

    Science.gov (United States)

    Yang, H.; Pasko, V. P.

    2003-12-01

    Resonance properties of the earth-ionosphere cavity were first predicted by W. O. Schumann in 1952 [Schumann, Z. Naturforsch. A, 7, 149, 1952]. Since then observations of extremely low frequency (ELF) signals in the frequency range 1-500 Hz have become a powerful tool for monitoring of global lightning activity and planetary scale variability of the lower ionosphere, as well as, in recent years, for location and remote sensing of sprites, jets and elves and associated lightning discharges [e.g., Sato et al., JASTP, 65, 607, 2003; Su et al., Nature, 423, 974, 2003; and references cited therein]. The simplicity and flexibility of finite difference time domain (FDTD) technique for finding first principles solutions of electromagnetic problems in a medium with arbitrary inhomogeneities and ever-increasing computer power make FDTD an excellent candidate to be the technique of the future in development of realistic numerical models of VLF/ELF propagation in Earth-ionosphere waveguide [Cummer, IEEE Trans. Antennas Propagat., 48, 1420, 2000], and several reports about successful application of the FDTD technique for solution of related problems have recently appeared in the literature [e.g., Thevenot et al., Ann. Telecommun., 54, 297, 1999; Cummer, 2000; Berenger, Ann. Telecommun., 57, 1059, 2002, Simpson and Taflove, IEEE Antennas Wireless Propagat. Lett., 1, 53, 2002]. In this talk we will present results from a new three-dimensional spherical FDTD model, which is designed for studies of ELF electromagnetic signals under 100 Hz in the earth-ionosphere cavity. The model accounts for a realistic latitudinal and longitudinal variation of ground conductivity (i.e., for the boundaries between oceans and continents) by employing a broadband surface impedance technique proposed in [Breggs et al., IEEE Trans. Antenna Propagat., 41, 118, 1993]. The realistic distributions of atmospheric/lower ionospheric conductivity are derived from the international reference ionosphere model

  1. Hybrid squeezing of solitonic resonant radiation in photonic crystal fibers

    CERN Document Server

    Tran, Truong X; Soeller, Christoph; Blow, Keith J; Biancalana, Fabio

    2011-01-01

    We report on the existence of a novel kind of squeezing in photonic crystal fibers which is conceptually intermediate between the four-wave mixing induced squeezing, in which all the participant waves are monochromatic waves, and the self-phase modulation induced squeezing for a single pulse in a coherent state. This hybrid squeezing occurs when an arbitrary short soliton emits quasi-monochromatic resonant radiation near a zero group velocity dispersion point of the fiber. Photons around the resonant frequency become strongly correlated due to the presence of the classical soliton, and a reduction of the quantum noise below the shot noise level is predicted.

  2. Magnetometry with nitrogen-vacancy ensembles in diamond based on infrared absorption in a doubly resonant optical cavity

    CERN Document Server

    Dumeige, Yannick; Jacques, Vincent; Treussart, François; Roch, Jean-François; Debuisschert, Thierry; Acosta, Victor; Jarmola, Andrey; Jensen, Kasper; Kehayias, Pauli; Budker, Dmitry

    2013-01-01

    We propose to use an optical cavity to enhance the sensitivity of magnetometers relying on the detection of the spin state of high-density nitrogen-vacancy ensembles in diamond using infrared optical absorption. The role of the cavity is to obtain a contrast in the absorption-detected magnetic resonance approaching unity at room temperature. We project an increase in the photon shot-noise limited sensitivity of two orders of magnitude in comparison with a single-pass approach. Optical losses can limit the enhancement to one order of magnitude which could still enable room temperature operation. Finally, the optical cavity also allows to use smaller pumping power when it is designed to be resonant at both the pump and the signal wavelength.

  3. Comparison of four computational methods for computing Q factors and resonance wavelengths in photonic crystal membrane cavities

    DEFF Research Database (Denmark)

    de Lasson, Jakob Rosenkrantz; Frandsen, Lars Hagedorn; Burger, Sven

    2016-01-01

    We benchmark four state-of-the-art computational methods 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 ofmodes is investigated. Special att...

  4. Mode coupling in terahertz metamaterials using sub-radiative and super-radiative resonators

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Shen; Zhang, Yaxin, E-mail: Zhangyaxin@uestc.edu.cn; Zhao, Yuncheng; Xu, Gaiqi; Sun, Han; Yang, Ziqiang [Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054 (China); Liang, Shixiong [National Key Laboratory of Application Specific Integrated Circuit, Hebei Semiconductor Research Institute, Shijiazhuang 050051 (China)

    2015-11-21

    We theoretically and experimentally explored the electromagnetically induced transparency (EIT) mode-coupling in terahertz (THz) metamaterial resonators, in which a dipole resonator with a super-radiative mode is coupled to an inductance-capacitance resonator with a sub-radiative mode. The interference between these two resonators depends on the relative spacing between them, resulting in a tunable transparency window in the absorption spectrum. Mode coupling was experimentally demonstrated for three spacing dependent EIT metamaterials. Transmittance of the transparency windows could be either enhanced or suppressed, producing different spectral linewidths. These spacing dependent mode-coupling metamaterials provide alternative ways to create THz devices, such as filters, absorbers, modulators, sensors, and slow-light devices.

  5. Dynamics of the cavity radiation of a correlated emission laser initially seeded with a thermal light

    Energy Technology Data Exchange (ETDEWEB)

    Tesfa, Sintayehu, E-mail: sint_tesfa@yahoo.com [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Street 38, 01187 Dresden (Germany); Physics Department, Dilla University, PO Box 419, Dilla (Ethiopia)

    2011-10-15

    A detailed analysis of the time evolution of the two-mode squeezing, entanglement and intensity of the cavity radiation of a two-photon correlated emission laser initially seeded with a thermal light is presented. The dependences of the degree of two-mode squeezing and entanglement on the intensity of the thermal light and time are found to have a more or less similar nature, although the actual values differ, especially in the early stages of the process and when the atoms are initially prepared with nearly 50:50 probability to be in the upper and lower energy levels. Seeding the cavity degrades the nonclassical features significantly, particularly in the vicinity of t=0. It is also shown that the mean photon number in a wider time span has a dip when mode b is seeded but a peak when mode a is seeded. Moreover, it turns out that the effect of the seed light on the nonclassical features and intensity of the cavity radiation decreases significantly with time, an outcome essentially attributed to the pertinent emission-absorption mechanism. This can be taken as an encouraging aspect in the practical utilization of this model as a source of a bright entangled light.

  6. Electromagnetic scattering and radiation from microstrip patch antennas and spirals residing in a cavity

    Science.gov (United States)

    Volakis, J. L.; Gong, J.; Alexanian, A.; Woo, A.

    1992-01-01

    A new hybrid method is presented for the analysis of the scattering and radiation by conformal antennas and arrays comprised of circular or rectangular elements. In addition, calculations for cavity-backed spiral antennas are given. The method employs a finite element formulation within the cavity and the boundary integral (exact boundary condition) for terminating the mesh. By virtue of the finite element discretization, the method has no restrictions on the geometry and composition of the cavity or its termination. Furthermore, because of the convolutional nature of the boundary integral and the inherent sparseness of the finite element matrix, the storage requirement is kept very low at O(n). These unique features of the method have already been exploited in other scattering applications and have permitted the analysis of large-size structures with remarkable efficiency. In this report, we describe the method's formulation and implementation for circular and rectangular patch antennas in different superstrate and substrate configurations which may also include the presence of lumped loads and resistive sheets/cards. Also, various modelling approaches are investigated and implemented for characterizing a variety of feed structures to permit the computation of the input impedance and radiation pattern. Many computational examples for rectangular and circular patch configurations are presented which demonstrate the method's versatility, modeling capability and accuracy.

  7. Monte Carlo radiative transfer simulation of a cavity solar reactor for the reduction of cerium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Villafan-Vidales, H.I.; Arancibia-Bulnes, C.A.; Dehesa-Carrasco, U. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Privada Xochicalco s/n, Col. Centro, A.P. 34, Temixco, Morelos 62580 (Mexico); Romero-Paredes, H. [Departamento de Ingenieria de Procesos e Hidraulica, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco No.186, Col. Vicentina, A.P. 55-534, Mexico D.F 09340 (Mexico)

    2009-01-15

    Radiative heat transfer in a solar thermochemical reactor for the thermal reduction of cerium oxide is simulated with the Monte Carlo method. The directional characteristics and the power distribution of the concentrated solar radiation that enters the cavity is obtained by carrying out a Monte Carlo ray tracing of a paraboloidal concentrator. It is considered that the reactor contains a gas/particle suspension directly exposed to concentrated solar radiation. The suspension is treated as a non-isothermal, non-gray, absorbing, emitting, and anisotropically scattering medium. The transport coefficients of the particles are obtained from Mie-scattering theory by using the optical properties of cerium oxide. From the simulations, the aperture radius and the particle concentration were optimized to match the characteristics of the considered concentrator. (author)

  8. 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.

  9. Geometrical resonance conditions for THz radiation from the intrinsic Josephson junctions in Bi(2)Sr(2)CaCu(2)O(8+δ).

    Science.gov (United States)

    Tsujimoto, Manabu; Yamaki, Kazuhiro; Deguchi, Kota; Yamamoto, Takashi; Kashiwagi, Takanari; Minami, Hidetoshi; Tachiki, Masashi; Kadowaki, Kazuo; Klemm, Richard A

    2010-07-16

    Subterahertz radiation emitted from a variety of short rectangular-, square-, and disk-shaped mesas of intrinsic Josephson junctions fabricated from a Bi(2)Sr(2)CaCu(2)O(8+δ) single crystal was studied from the observed I-V characteristics, far-infrared spectra, and spatial radiation patterns. In all cases, the radiation frequency satisfies the conditions both for the ac Josephson effect and for a mesa cavity resonance mode. The integer higher harmonics observed in all spectra imply that the ac Josephson effect plays the dominant role in the novel dual-source radiation mechanism.

  10. Relativistic surfatron process for Landau resonant electrons in radiation belts

    CERN Document Server

    Osmane, A

    2014-01-01

    Recent theoretical studies of the nonlinear wave-particle interactions for relativistic particles have shown that Landau resonant orbits could be efficiently accelerated along the mean background magnetic field for propagation angles $\\theta$ in close proximity to a critical propagation $\\theta_\\textrm{c}$ associated with a Hopf--Hopf bifurcation condition. In this report, we extend previous studies to reach greater modeling capacities for the study of electrons in radiation belts by including longitudinal wave effects and inhomogeneous magnetic fields. We find that even though both effects can limit the surfatron acceleration of electrons in radiation belts, gains in energy of the order of 100 keV, taking place on the order of ten milliseconds, are sufficiently strong for the mechanism to be relevant to radiation belt dynamics.

  11. Spin amplification in solution magnetic resonance using radiation damping.

    Science.gov (United States)

    Walls, Jamie D; Huang, Susie Y; Lin, Yung-Ya

    2007-08-07

    The sensitive detection of dilute solute spins is critical to biomolecular NMR. In this work, a spin amplifier for detecting dilute solute magnetization is developed using the radiation damping interaction in solution magnetic resonance. The evolution of the solvent magnetization, initially placed along the unstable -z direction, is triggered by the radiation damping field generated by the dilute solute magnetization. As long as the radiation damping field generated by the solute is larger than the corresponding thermal noise field generated by the sample coil, the solute magnetization can effectively trigger the evolution of the water magnetization under radiation damping. The coupling between the solute and solvent magnetizations via the radiation damping field can be further improved through a novel bipolar gradient scheme, which allows solute spins with chemical shift differences much greater than the effective radiation damping field strength to affect the solvent magnetizations more efficiently. Experiments performed on an aqueous acetone solution indicate that solute concentrations on the order of 10(-5) that of the solvent concentration can be readily detected using this spin amplifier.

  12. Radiation and Resonant Frequency of Superconducting Annular Ring Microstrip Antenna on Uniaxial Anisotropic Media

    Science.gov (United States)

    Barkat, Ouarda; Benghalia, Abdelmadjid

    2009-10-01

    In this work, the full-wave method is used for computing the resonant frequency, the bandwidth, and radiation pattern of High temperature superconductor, or an imperfectly conducting annular ring microstrip, which is printed on uniaxial anisotropic substrate. Galerkin’s method is used in the resolution of the electric field integral equation. The TM set of modes issued from the cavity model theory are used to expand the unknown currents on the patch. Numerical results concerning the effect of the anisotropic substrates on the antenna performance are presented and discussed. It is found that microstrip superconducting could give high efficiency with high gain in millimeter wavelengths. Results are compared with previously published data and are found to be in good agreement.

  13. Local thermal resonance control of GaInP photonic crystal membrane cavities using ambient gas cooling

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Sergei, E-mail: s.sokolov@utwente.nl; Lian, Jin; Yüce, Emre; Mosk, Allard P. [Complex Photonic Systems (COPS), MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands); Combrié, Sylvain; Lehoucq, Gaelle; De Rossi, Alfredo [Thales Research and Technology, Route Départementale 128, 91767 Palaiseau (France)

    2015-04-27

    We perform spatially dependent tuning of a GaInP photonic crystal cavity using a continuous wave violet laser. Local tuning is obtained by laser heating of the photonic crystal membrane. The cavity resonance shift is measured for different pump positions and for two ambient gases: He and N{sub 2}. We find that the width of the temperature profile induced in the membrane depends strongly on the thermal conductivity of the ambient gas. For He gas, a narrow spatial width of the temperature profile of 2.8 μm is predicted and verified in experiment.

  14. Scheme for on-resonance generation of entanglement in time-dependent asymmetric two-qubit-cavity systems

    Science.gov (United States)

    Olaya-Castro, Alexandra; Johnson, Neil F.; Quiroga, Luis

    2004-08-01

    We present an efficient scheme for the controlled generation of pure two-qubit states possessing any desired degree of entanglement and a prescribed symmetry. This is achieved in two-qubit-cavity QED systems (e.g., cold-trapped ions and flying atoms) via on-resonance ion- or atom-cavity couplings, which are time dependent and asymmetric, yielding a trapping vacuum state condition which does not arise for identical couplings. A duality in the role of the coupling ratio yields states with a given concurrence but opposing symmetries. Both the trapping state condition and the resulting entanglement power are robust against decoherence channels.

  15. 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.

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

    Science.gov (United States)

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

    2016-06-01

    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 populate an intermediate vibrational state. High output power of the optical parametric oscillator and the strength of the mid-infrared transition result in efficient population transfer to the intermediate state, which allows measuring secondary transitions from this state with a high signal-to-noise ratio. A secondary, near-infrared transition from the intermediate state is probed using cavity ring-down spectroscopy, which provides high sensitivity in this wavelength region. Due to the narrow linewidths of the excitation sources, the rovibrational lines of the secondary transition are measured with sub-Doppler resolution. The setup is used to access a previously unreported symmetric vibrational state of acetylene, ν 1 + ν 2 + ν 3 + ν4 1 + ν5 - 1 in the normal mode notation. Single-photon transitions to this state from the vibrational ground state are forbidden. Ten lines of the newly measured state are observed and fitted with the linear least-squares method to extract the band parameters. The vibrational term value was measured to be at 9775.0018(45) cm-1, the rotational parameter B was 1.162 222(37) cm-1, and the quartic centrifugal distortion parameter D was 3.998(62) × 10-6 cm-1, where the numbers in the parenthesis are one-standard errors in the least significant digits.

  17. 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.

  18. Radiation and scattering by cavity-backed antennas on a circular cylinder

    Science.gov (United States)

    Kempel, Leo C.; Volakis, John L.

    1993-01-01

    Conformal arrays are popular antennas for aircraft and missile platforms due to their inherent low weight and drag properties. However, to date there has been a dearth of rigorous analytical or numerical solutions to aid the designer. In fact, it has been common practice to use limited measurements and planar approximations in designing such non-planar antennas. The finite element-boundary integral method is extended to scattering and radiation by cavity-backed structures in an infinite, metallic cylinder. In particular, the formulation specifics such as weight functions, dyadic Green's function, implementation details, and particular difficulties inherent to cylindrical structures are discussed. Special care is taken to ensure that the resulting computer program has low memory demand and minimal computational requirements. Both scattering and radiation parameters are computed and validated as much as possible.

  19. 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.

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

    Science.gov (United States)

    Gentle, A. R.; Yambem, S. D.; Burn, P. L.; Meredith, P.; Smith, G. B.

    2016-06-01

    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.

  1. Fano-resonance induced strong-coupling of a hyperbolic cavity to a quantum emitter

    CERN Document Server

    Hasan, Mehedi; Belov, Pavel

    2015-01-01

    Light-matter interaction is studied for an open quantum system in the strong-coupling regime. A quantum dot and a hyperbolic cavity of spherical geometry is shown to couple light with large Rabi frequency and the role of Fano resonance is shown in the coupling mechanism. High Purcell factor and large Lamb shift are outlined. In the near-field spectrum, two distinct anti-crossings are evident, namely -- the one near the epsilon near zero (ENZ) frequency (from the effective medium description) which is detectable in the far-field, and the second anti-crossing is a pseudomode that does not appear in the far-field spectrum. This delineates the phenomenon `farfield propagating large Purcell factor'. Finally, we remark the fidelity of the strong-coupling, i.e. how prone the strong-coupling with respect to the loss mechanisms. This study on strong-coupling will have applications for spectroscopy, control over chemical reaction rate, microcavity, and in quantum information technology.

  2. Radiative neutron capture: Hauser Feshbach vs. statistical resonances

    Science.gov (United States)

    Rochman, D.; Goriely, S.; Koning, A. J.; Ferroukhi, H.

    2017-01-01

    The radiative neutron capture rates for isotopes of astrophysical interest are commonly calculated on the basis of the statistical Hauser Feshbach (HF) reaction model, leading to smooth and monotonically varying temperature-dependent Maxwellian-averaged cross sections (MACS). The HF approximation is known to be valid if the number of resonances in the compound system is relatively high. However, such a condition is hardly fulfilled for keV neutrons captured on light or exotic neutron-rich nuclei. For this reason, a different procedure is proposed here, based on the generation of statistical resonances. This novel technique, called the "High Fidelity Resonance" (HFR) method is shown to provide similar results as the HF approach for nuclei with a high level density but to deviate and be more realistic than HF predictions for light and neutron-rich nuclei or at relatively low sub-keV energies. The MACS derived with the HFR method are systematically compared with the traditional HF calculations for some 3300 neutron-rich nuclei and shown to give rise to significantly larger predictions with respect to the HF approach at energies of astrophysical relevance. For this reason, the HF approach should not be applied to light or neutron-rich nuclei. The Doppler broadening of the generated resonances is also studied and found to have a negligible impact on the calculated MACS.

  3. Observation of Wakefields and Resonances in Coherent Synchrotron Radiation

    CERN Document Server

    Billinghurst, B E; Baribeau, C; Batten, T; Dallin, L; May, T E; Vogt, J M; Wurtz, W A; Warnock, R; Bizzizero, D A; Kramer, S

    2015-01-01

    We report on high resolution measurements of resonances in the spectrum of coherent synchrotron radiation (CSR) at the Canadian Light Source (CLS). The resonances permeate the spectrum at wavenumber intervals of $0.074 ~\\textrm{cm}^{-1}$, and are highly stable under changes in the machine setup (energy, bucket filling pattern, CSR in bursting or continuous mode). Analogous resonances were predicted long ago in an idealized theory as eigenmodes of a smooth toroidal vacuum chamber driven by a bunched beam moving on a circular orbit. A corollary of peaks in the spectrum is the presence of pulses in the wakefield of the bunch at well defined spatial intervals. Through experiments and further calculations we elucidate the resonance and wakefield mechanisms in the CLS vacuum chamber, which has a fluted form much different from a smooth torus. The wakefield is observed directly in the 30-110 GHz range by RF diodes, and indirectly by an interferometer in the THz range. The wake pulse sequence found by diodes is less ...

  4. Optical gain from vertical Ge-on-Si resonant-cavity light emitting diodes with dual active regions

    Science.gov (United States)

    Lin, Guangyang; Wang, Jiaqi; Huang, Zhiwei; Mao, Yichen; Li, Cheng; Huang, Wei; Chen, Songyan; Lai, Hongkai; Huang, Shihao

    2017-09-01

    Vertical resonant-cavity light emitting diodes with dual active regions consisting of highly n-doped Ge/GeSi multiple quantum wells (MQWs) and a Ge epilayer are proposed to improve the light emitting efficiency. The MQWs are designed to optically pump the underlying Ge epilayer under electric injection. Abundant excess carriers can be optically pumped into the Γ valley of the Ge epilayer apart from electric pumping. With the combination of a vertical cavity, the efficiency of the optical-pumping process was effectively improved due to the elongation of the optical length in the cavity. With the unique feature, optical gain from the Ge epilayer is observed between 1625 and 1700 nm at injection current densities of >1.528 kA/cm2. The demonstration of optical gain from the Ge epilayer indicates that this strategy can be generally useful for Si-based light sources with indirect band materials.

  5. Controllable optical response by modifying the gain and loss of a mechanical resonator and cavity mode in an optomechanical system

    CERN Document Server

    Liu, Yu-Long; Zhang, Jing; Özdemir, Şahin Kaya; Yang, Lan; Nori, Franco; Liu, Yu-xi

    2016-01-01

    We theoretically study a strongly-driven optomechanical system which consists of a passive optical cavity and an active mechanical resonator. When the optomechanical coupling strength is varied, phase transitions, which are similar those observed in $\\mathcal{PT}$-symmetric systems, are observed. We show that the optical transmission can be controlled by changing the gain of the mechanical resonator and loss of the optical cavity mode. Especially, we find that: (i) for balanced gain and loss, optical amplification and absorption can be tuned by changing the optomechanical coupling strength through a control field; (ii) for unbalanced gain and loss, even with a tiny mechanical gain, both optomechanically-induced transparency and anomalous dispersion can be observed around a critical point, which exhibits an ultra-long group delay. The time delay $\\tau$ can be optimized by regulating the optomechanical coupling strength through the control field and improved up to several orders of magnitude ($\\tau\\sim2$ $\\math...

  6. Fano Resonance Based on Metal-Insulator-Metal Waveguide-Coupled Double Rectangular Cavities for Plasmonic Nanosensors

    Directory of Open Access Journals (Sweden)

    Zhidong Zhang

    2016-05-01

    Full Text Available A refractive index sensor based on metal-insulator-metal (MIM waveguides coupled double rectangular cavities is proposed and investigated numerically using the finite element method (FEM. The transmission properties and refractive index sensitivity of various configurations of the sensor are systematically investigated. An asymmetric Fano resonance lineshape is observed in the transmission spectra of the sensor, which is induced by the interference between a broad resonance mode in one rectangular and a narrow one in the other. The effect of various structural parameters on the Fano resonance and the refractive index sensitivity of the system based on Fano resonance is investigated. The proposed plasmonic refractive index sensor shows a maximum sensitivity of 596 nm/RIU.

  7. 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....

  8. A Photonic Crystal Magnetic Field Sensor Using a Shoulder-Coupled Resonant Cavity Infiltrated with Magnetic Fluid.

    Science.gov (United States)

    Su, Delong; Pu, Shengli; Mao, Lianmin; Wang, Zhaofang; Qian, Kai

    2016-12-16

    A kind of photonic crystal magnetic field sensor is proposed and investigated numerically. The shoulder-coupled resonant cavity is introduced in the photonic crystal, which is infiltrated with magnetic fluid. Through monitoring the shift of resonant wavelength, the magnetic field sensing is realized. According to the designed infiltration schemes, both the magnetic field sensitivity and full width at half maximum increase with the number of infiltrated air holes. The figure of merit of the structure is defined to evaluate the sensing performance comprehensively. The best structure corresponding to the optimal infiltration scheme with eight air holes infiltrated with magnetic fluid is obtained.

  9. Cyclotron Resonance Gain for FIR and THz Radiation in Graphene

    CERN Document Server

    Cole, Nightvid

    2016-01-01

    A cyclotron resonance maser source using low-effective-mass conduction electrons in graphene, if successful, would allow for generation of Far Infrared (FIR) and Terahertz (THz) radiation without requiring magnetic fields running into the tens of Tesla. In order to investigate this possibility, we consider a device in which electrons are effectively injected via pumping from the valence band to the conduction band using an infrared (IR) laser source, subsequently gyrate in a magnetic field applied perpendicular to the plane of the graphene, and give rise to gain for a FIR/THz wave crossing the plane of the graphene. A set of integral expressions is derived by assuming that the non-radiative energy loss processes of the electrons can be adequately represented by a damping force proportional and antiparallel to their momentum. Minimal gain may occur at very short electron damping times of hundreds of femtoseconds.

  10. Classical theory of resonant transition radiation in multilayer structures.

    Science.gov (United States)

    Pardo, B; André, J M

    2001-01-01

    A rigorous classical electromagnetic theory of the transition radiation in finite and infinite multilayer structures is presented. It makes the standard results of thin-film optics, such as the matrix formalism, accountable; it allows thus an exact treatment of the propagation of the waves induced by the electron. This method is applied to the particular case of the periodic structures to treat the resonant transition radiation (RTR). It is noted that the present theory gives, in the hard x-ray domain, results previously published. The reason for this approach is to make the numerical calculations rigorous and easy. The numerical results of our theory are compared to experimental RTR data obtained recently by Yamada et al. [Phys. Rev. A 59, 3673 (1999)] with a nickel-carbon multilayer structure.

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

    OpenAIRE

    Paolo Bardella; Chow, Weng W.; Ivo Montrosset

    2016-01-01

    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 ...

  12. High-Speed Widely-Tunable 90% Quantum-Efficiency Resonant Cavity Enhanced p-i-n Photodiodes

    Science.gov (United States)

    1998-12-01

    REPORT unclassified b . ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 8:45am - 9...00am WB2 High-Speed Widely-Tunable >90% Quantum-Efficiency Resonant Cavity Enhanced p-i-n Photodiodes Necmi Biyiklia. Ibrahim Kimukinb. Orhan ...Bilkent, Ankara 06533, Turkey. b Department of Physics, Bilkent University, Bilkent, Ankara 06533, Turkey. c Department of Electrical and Computer

  13. Radiation-induced optic neuropathy: A magnetic resonance imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Guy, J.; Mancuso, A.; Beck, R.; Moster, M.L.; Sedwick, L.A.; Quisling, R.G.; Rhoton, A.L. Jr.; Protzko, E.E.; Schiffman, J. (Univ. of Florida, Gainesville (USA))

    1991-03-01

    Optic neuropathy induced by radiation is an infrequent cause of delayed visual loss that may at times be difficult to differentiate from compression of the visual pathways by recurrent neoplasm. The authors describe six patients with this disorder who experienced loss of vision 6 to 36 months after neurological surgery and radiation therapy. Of the six patients in the series, two had a pituitary adenoma and one each had a metastatic melanoma, multiple myeloma, craniopharyngioma, and lymphoepithelioma. Visual acuity in the affected eyes ranged from 20/25 to no light perception. Magnetic resonance (MR) imaging showed sellar and parasellar recurrence of both pituitary adenomas, but the intrinsic lesions of the optic nerves and optic chiasm induced by radiation were enhanced after gadolinium-diethylenetriaminepenta-acetic acid (DTPA) administration and were clearly distinguishable from the suprasellar compression of tumor. Repeated MR imaging showed spontaneous resolution of gadolinium-DTPA enhancement of the optic nerve in a patient who was initially suspected of harboring recurrence of a metastatic malignant melanoma as the cause of visual loss. The authors found the presumptive diagnosis of radiation-induced optic neuropathy facilitated by MR imaging with gadolinium-DTPA. This neuro-imaging procedure may help avert exploratory surgery in some patients with recurrent neoplasm in whom the etiology of visual loss is uncertain.

  14. Investigating the electron density of multi-MeV X-ray-induced air plasmas at low pressures based on electromagnetic resonant cavity analysis

    Science.gov (United States)

    Ribière, M.; d'Almeida, T.; Cessenat, O.; Maulois, M.; Pouzalgues, R.; Crabos, B.; Delbos, C.; Garrigues, A.; Azaïs, B.

    2016-12-01

    We investigate air plasmas generated by multi-MeV pulsed X-rays at pressures ranging from 10-5 to 10-1 mbar. The experimental approach used for these studies is based on measurements of resonant frequencies damping and shift for different electromagnetic modes within a cylindrical cavity. Time-integrated electron densities in X-ray-induced air plasmas are inferred from the damping rate of the measured magnetic fields and their corresponding frequency shifts. In the present study, electron densities ranging from 108 to 109 cm-3 at pressures ranging from 10-3 to 10-1 mbar have been measured. Experimental results were confronted to 3D Maxwell-Vlasov Particle-In-Cell simulations incorporating a radiation-induced electric conductivity model. The method used in this work enables determining microscopic and macroscopic physical quantities within low pressure air plasmas generated by pulsed X-ray.

  15. 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.

  16. Radiative neutron capture: Hauser Feshbach vs. statistical resonances

    Directory of Open Access Journals (Sweden)

    D. Rochman

    2017-01-01

    Full Text Available The radiative neutron capture rates for isotopes of astrophysical interest are commonly calculated on the basis of the statistical Hauser Feshbach (HF reaction model, leading to smooth and monotonically varying temperature-dependent Maxwellian-averaged cross sections (MACS. The HF approximation is known to be valid if the number of resonances in the compound system is relatively high. However, such a condition is hardly fulfilled for keV neutrons captured on light or exotic neutron-rich nuclei. For this reason, a different procedure is proposed here, based on the generation of statistical resonances. This novel technique, called the “High Fidelity Resonance” (HFR method is shown to provide similar results as the HF approach for nuclei with a high level density but to deviate and be more realistic than HF predictions for light and neutron-rich nuclei or at relatively low sub-keV energies. The MACS derived with the HFR method are systematically compared with the traditional HF calculations for some 3300 neutron-rich nuclei and shown to give rise to significantly larger predictions with respect to the HF approach at energies of astrophysical relevance. For this reason, the HF approach should not be applied to light or neutron-rich nuclei. The Doppler broadening of the generated resonances is also studied and found to have a negligible impact on the calculated MACS.

  17. 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.

  18. 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.

  19. Cavity mode waves during terahertz radiation from rectangular Bi(2)Sr(2)CaCu(2)O(8 + δ) mesas.

    Science.gov (United States)

    Klemm, Richard A; Laberge, Erica R; Morley, Dustin R; Kashiwagi, Takanari; Tsujimoto, Manabu; Kadowaki, Kazuo

    2011-01-19

    We re-examined the angular dependence of the radiation from the intrinsic Josephson junctions in rectangular mesas of Bi(2)Sr(2)CaCu(2)O(8 + δ), in order to determine if the cavity mode part of the radiation arises from waves across the width w or along the length l of the mesas, associated with 'hot spots' (Wang et al 2010 Phys. Rev. Lett. 105 057002). We derived analytical forms for the angular dependence expected in both cases for a general cavity mode in which the width of the mesa corresponds to an integer multiple of one-half the wavelength of the radiation. Assuming the coherent radiation from the ac Josephson current source and the cavity magnetic surface current density source combine incoherently, fits to the data of Kadowaki et al (2010 J. Phys. Soc. Japan 79 023703) on a mesa with mean l/ω = 5.17 for both wave directions using two models for the incoherent combination were made, which correspond to standing and traveling waves, respectively. The results suggest that the combined output from the uniform ac Josephson current source plus a cavity wave forming along the rectangle length is equally probable as that of the combined output from the uniform ac Josephson current plus a cavity wave across the width. However, for mesas in which nl/2ω is integral, where n is the index of the rectangular TM(z)(n, 0) mode, it is shown that standing cavity mode waves along the length of the mesa do not radiate in the xz plane perpendicular to the length of the mesa, suggesting experiments on such mesas could help to resolve the question.

  20. Cavity mode waves during terahertz radiation from rectangular Bi2Sr2CaCu2O8 + δ mesas

    Science.gov (United States)

    Klemm, Richard A.; LaBerge, Erica R.; Morley, Dustin R.; Kashiwagi, Takanari; Tsujimoto, Manabu; Kadowaki, Kazuo

    2011-01-01

    We re-examined the angular dependence of the radiation from the intrinsic Josephson junctions in rectangular mesas of Bi2Sr2CaCu2O8 + δ, in order to determine if the cavity mode part of the radiation arises from waves across the width w or along the length \\ell of the mesas, associated with 'hot spots' (Wang et al 2010 Phys. Rev. Lett. 105 057002). We derived analytical forms for the angular dependence expected in both cases for a general cavity mode in which the width of the mesa corresponds to an integer multiple of one-half the wavelength of the radiation. Assuming the coherent radiation from the ac Josephson current source and the cavity magnetic surface current density source combine incoherently, fits to the data of Kadowaki et al (2010 J. Phys. Soc. Japan 79 023703) on a mesa with mean \\ell /w=5.17 for both wave directions using two models for the incoherent combination were made, which correspond to standing and traveling waves, respectively. The results suggest that the combined output from the uniform ac Josephson current source plus a cavity wave forming along the rectangle length is equally probable as that of the combined output from the uniform ac Josephson current plus a cavity wave across the width. However, for mesas in which n\\ell /2w is integral, where n is the index of the rectangular TMzn, 0 mode, it is shown that standing cavity mode waves along the length of the mesa do not radiate in the xz plane perpendicular to the length of the mesa, suggesting experiments on such mesas could help to resolve the question.

  1. Current-voltage characteristic of a resonant tunneling diode under electromagnetic radiation

    National Research Council Canada - National Science Library

    N Hatefi Kargan

    2013-01-01

    In this paper, current-voltage characteristic of a resonant tunneling diode under electromagnetic radiation has been calculated and compared with the results when there is no electromagnetic radiation...

  2. Linear and nonlinear resonance features of an erbium-doped fibre ring laser under cavity-loss modulation

    Indian Academy of Sciences (India)

    Aditi Ghosh; R Vijaya

    2014-07-01

    The continuous-wave output of a single-mode erbium-doped fibre ring laser when subjected to cavity-loss modulation is found to exhibit linear as well as nonlinear resonances. At sufficiently low driving amplitude, the system resembles a linear damped oscillator. At higher amplitudes, the dynamical study of these resonances shows that the behaviour of the system exhibits features of a nonlinear damped oscillator under harmonic modulation. These nonlinear dynamical features, including harmonic and subharmonic resonances, have been studied experimentally and analysed with the help of a simple time-domain and frequency-domain information obtained from the output of the laser. All the studies are restricted to the modulation frequency lying in a regime near the relaxation oscillation frequency.

  3. Nonlinear Cavity and Frequency Comb Radiations Induced by Negative Frequency Field Effects

    Science.gov (United States)

    Lourés, Cristian Redondo; Faccio, Daniele; Biancalana, Fabio

    2015-11-01

    Optical Kerr frequency combs (KFCs) are an increasingly important optical metrology tool with applications ranging from ultraprecise spectroscopy to time keeping. KFCs may be generated in compact resonators with extremely high quality factors. Here, we show that the same features that lead to high quality frequency combs in these resonators also lead to an enhancement of nonlinear emissions that may be identified as originating from the presence of a negative frequency (NF) component in the optical spectrum. While the negative frequency component of the spectrum is naturally always present in the real-valued optical field, it is not included in the principal theoretical model used to model nonlinear cavities, i.e., the Lugiato-Lefever equation. We therefore extend these equations in order to include the contribution of NF components and show that the predicted emissions may be studied analytically, in excellent agreement with full numerical simulations. These results are of importance for a variety of fields, such as Bose-Einstein condensates, mode-locked lasers, nonlinear plasmonics, and polaritonics.

  4. Simulation of a birdcage and a ceramic cavity HF-resonator for high magnetic fields in magnetic resonance imaging.

    Science.gov (United States)

    Eriksen, E; Golombeck, M A; Junge, S; Dössel, O

    2002-01-01

    The aim of this work was the 3D-simulation of a dielectric resonator for high-field-MRI. A 12-rod-bird-cage-resonator was simulated in a first step, in order to verify the capability of the commercial simulation software MAFIA to simulate homogeneous, transversal B-fields in resonators. The second step was the simulation of frequency-independent dielectric ceramic resonators for static magnetic field strengths of 7 T and 12 T (294 MHz and 504 MHz respectively). The results were compared to the measured results of a manufactured TiO2- and a Al2O3-resonator. Only minor deviations showed up. These results led to the conclusion that dielectric resonators for high field MRI can be optimised using numerical field calculation software.

  5. Numerical research of dynamic characteristics in tower solar cavity receiver based on step-change radiation flux

    Science.gov (United States)

    Chen, Zhengwei; Wang, Yueshe; Hao, Yun; Wang, Qizhi

    2013-07-01

    The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux in the inner surface of the cavity will show the characteristics of non-continuous step change especially in non-normal and transient weather conditions, which may result in a continuous dynamic variation of the characteristic parameters. Therefore, the research of dynamic characteristics of the receiver plays a very important role in the operation and the control safely in solar cavity receiver system. In this paper, based on the non-continuous step change of radiation flux, a non-linear dynamic model is put forward to obtain the effects of the non-continuous step change radiation flux and step change feed water flow on the receiver performance by sequential modular approach. The subject investigated in our study is a 1MW solar power station constructed in Yanqing County, Beijing. This study has obtained the dynamic responses of the characteristic parameters in the cavity receiver, such as drum pressure, drum water level, main steam flow and main steam enthalpy under step change radiation flux. And the influence law of step-change feed water flow to the dynamic characteristics in the receiver also has been analyzed. The results have a reference value for the safe operation and the control in solar cavity receiver system.

  6. Research of seal materials adhesion to walls of cavity in enamel and dentin formation by Er laser radiation

    Science.gov (United States)

    Altshuler, Gregory B.; Belikov, Andrei V.; Vlasova, Svetlana N.; Erofeev, Andrew V.

    1994-12-01

    The present work represents the results of research of mechanical strength formed by submillisecond pulses of Er-laser at the border of enamel-seal and dentine-seal in a cavity. Comparative research of an adhesion of three of the most widespread types of modern seal materials (cement, amalgam, polymer) to walls of the laser cavity are conducted. The comparison of `laser adhesion' with adhesion of these materials to the walls of the cavity has been made by the usual mechanical tools. The dependence of free adhesion energy from the geometry of the cavity and energy density of laser radiation is considered. This work informs the reader about the results of research removal efficiency of some modern seal materials. The influence of water-spray on the efficiency of seal materials laser treatment process is considered.

  7. Axially uniform magnetic field-modulation excitation for electron paramagnetic resonance in rectangular and cylindrical cavities by slot cutting

    Science.gov (United States)

    Sidabras, Jason W.; Richie, James E.; Hyde, James S.

    2017-01-01

    In continuous-wave (CW) Electron Paramagnetic Resonance (EPR) a low-frequency time-harmonic magnetic field, called field modulation, is applied parallel to the static magnetic field and incident on the sample. Varying amplitude of the field modulation incident on the sample has consequences on spectral line-shape and line-height over the axis of the sample. Here we present a method of coupling magnetic field into the cavity using slots perpendicular to the sample axis where the slot depths are designed in such a way to produce an axially uniform magnetic field along the sample. Previous literature typically assumes a uniform cross-section and axial excitation due to the wavelength of the field modulation being much larger than the cavity. Through numerical analysis and insights obtained from the eigenfunction expansion of dyadic Green's functions, it is shown that evanescent standing-wave modes with complex cross-sections are formed within the cavity. From this analysis, a W-band (94 GHz) cylindrical cavity is designed where modulation slots are optimized to present a uniform 100 kHz field modulation over the length of the sample.

  8. Compact photonic crystal circulator with flat-top transmission band created by cascading magneto-optical resonance cavities.

    Science.gov (United States)

    Wang, Qiong; Ouyang, Zhengbiao; Lin, Mi; Liu, Qiang

    2015-11-20

    A new type of compact three-port circulator with flat-top transmission band (FTTB) in a two-dimensional photonic crystal has been proposed, through coupling the cascaded magneto-optical resonance cavities to waveguides. The coupled-mode theory is applied to investigate the coupled structure and analyze the condition to achieve FTTB. According to the theoretical analysis, the structure is further optimized to ensure that the condition for achieving FTTB can be satisfied for both cavity-cavity coupling and cavity-waveguide coupling. Through the finite-element method, it is demonstrated that the design can realize a high quality, nonreciprocal circulating propagation of waves with an insertion loss of 0.023 dB and an isolation of 23.3 dB, covering a wide range of operation frequency. Such a wideband circulator has potential applications in large-scale integrated photonic circuits for guiding or isolating harmful optical reflections from load elements.

  9. Experimental evaluation of self-calibrating cavity radiometers for use in earth flux radiation balance measurements from satellites

    Science.gov (United States)

    Hickey, J. R.; Karoli, A. R.; Alton, B. M.

    1982-01-01

    A method for evaluating out-of-field response of wide-field, earth-viewing satellite radiometers is described. The equipment which simulates the earth and space consists of a central blackbody surrounded by a cooled ring. The radiometric and orbital considerations are discussed. Some test results for prototype ERBE cavity sensors are included. This presentation is restricted to longwave radiative transfer

  10. Spinal cord cavities; Differential-diagnostic criteria in magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Schubeus, P.; Schoerner, W.; Hosten, N.; Felix, R. (Free University of Berlin, University Clinic Rudolf Virchow, Charlottenburg (Germany). Department of Radiology)

    MRI examinations of 30 patients with idiopathic syringomyelia and 10 patients with cavities associated with an intramedullary neoplasm were evaluated with respect to typical MRI features in both groups. Al tumor-associated cases resembled the idiopathic syringomyelias in some portions of the cavity. At the tumor site, however, tumor-associated cases demonstrated typical findings; the cavities showed abrupt changes of diameter (10/10) and position (8/10) and the surrounding spinal cord demonstrated an uneven thickness (10/10), an increased signal intensity on T2-weighted images (10/10) and pathological contrast enhancement (7/7). Displacement of cerebellar tonsils below the level of the foramen magnum (921/30) and enlargement of the spinal canal (97/29) were characteristic features of idiopathic cases. In conclusion, MRI provides valuable criteria to differentiate between idiopathic and tumor-associated cavities. (author). 19 refs.; 4 figs.; 1 tab.

  11. Coherent coupling of molecular resonators with a micro-cavity mode

    CERN Document Server

    Shalabney, Atef; Hutchison, James A; Pupillo, Guido; Genet, Cyriaque; Ebbesen, Thomas W

    2014-01-01

    Strong coupling is at the heart of optomechanics where it enables coherent quantum state transfer between light and micromechanical oscillators. Strongly coupled molecule-cavity systems have also revealed unique properties enabling even the control of chemical rates through the optical hybridization of the electronic states. Here we combine these notions to show that molecular vibrational modes of the electronic ground state can be coherently coupled with a micro-cavity mode at room temperature, given the low vibrational thermal occupation factors n_{\

  12. Determination of the quasi-TE mode (in-plane) graphene linear absorption coefficient via integration with silicon-on-insulator racetrack cavity resonators.

    Science.gov (United States)

    Crowe, Iain F; Clark, Nicholas; Hussein, Siham; Towlson, Brian; Whittaker, Eric; Milosevic, Milan M; Gardes, Frederic Y; Mashanovich, Goran Z; Halsall, Matthew P; Vijayaraghaven, Aravind

    2014-07-28

    We examine the near-IR light-matter interaction for graphene integrated cavity ring resonators based on silicon-on-insulator (SOI) race-track waveguides. Fitting of the cavity resonances from quasi-TE mode transmission spectra reveal the real part of the effective refractive index for graphene, n(eff) = 2.23 ± 0.02 and linear absorption coefficient, α(gTE) = 0.11 ± 0.01dBμm(-1). The evanescent nature of the guided mode coupling to graphene at resonance depends strongly on the height of the graphene above the cavity, which places limits on the cavity length for optical sensing applications.

  13. Average radiation widths and the giant dipole resonance width

    Energy Technology Data Exchange (ETDEWEB)

    Arnould, M.; Thielemann, F.K.

    1982-11-01

    The average E1 radiation width can be calculated in terms of the energy Esub(G) and width GAMMAsub(G) of the Giant Dipole Resonance (GDR). While various models can predict Esub(G) quite reliably, the theoretical situation regarding ..lambda..sub(G) is much less satisfactory. We propose a simple phenomenological model which is able to provide GAMMAsub(G) values in good agreement with experimental data for spherical or deformed intermediate and heavy nuclei. In particular, this model can account for shell effects in GAMMAsub(G), and can be used in conjunction with the droplet model. The GAMMAsub(G) values derived in such a way are used to compute average E1 radiation widths which are quite close to the experimental values. The method proposed for the calculation of GAMMAsub(G) also appears to be well suited when the GDR characteristics of extended sets of nuclei are required, as is namely the case in nuclear astrophysics.

  14. Infrared-microwave double resonance: signal dependence on microwave radiation strength

    NARCIS (Netherlands)

    Vreede, J.P.M. de; Dijkerman, H.A.

    1980-01-01

    The influence of MW radiation on the magnitude of double resonance signals is studied in the case of steady-state 3-level IR-MW double resonance, using IR or MW radiation as probe field. The measurements reveal a strong signal dependence on the microwave power level. Changes in the absorption factor

  15. Triple-resonant Brillouin light scattering in magneto-optical cavities

    CERN Document Server

    Haigh, J A; Ramsay, A J; Ferguson, A J

    2016-01-01

    An enhancement in Brillouin light scattering of optical photons with magnons is demonstrated in magneto-optical whispering gallery mode resonators tuned to a triple resonance point. This occurs when both the input and output optical modes are resonant with those of the whispering gallery resonator, with a separation given by the ferromagnetic resonance (FMR) frequency. The identification and excitation of specific optical modes allows us to gain a clear understanding of the mode-matching conditions. A selection rule due to wavevector matching leads to an intrinsic single-sideband excitation. Strong suppression of one sideband is essential for one-to-one frequency mapping in coherent optical-to-microwave conversion.

  16. Metallic Photonic Bandgap Resonant Antennas with High Directivity and High Radiation Resistance

    Institute of Scientific and Technical Information of China (English)

    林青春; 符建; 何赛灵; 章坚武

    2002-01-01

    A metallic photonic bandgap (MPBG) resonant antenna is introduced, which has novel characteristics (such as high directivity and high radiation resistance for a certain range of frequencies) as compared to conventional MPBG antennas. The linear MPBG resonant antenna is formed by infinitely long metallic rods in vacuum. The numerical results for the radiation pattern and the radiation resistance are presented. By adjusting the struct ure of the MPBG resonant antenna and its working frequency, an optimal structure is achieved. The physical reasons for the novel characteristics of the MPBG resonant antenna are also explained.

  17. Tuning of Detection Wavelength in a Resonant-Cavity-Enhanced Quantum-Dot-Embedded Photodiode by Changing Detection Angle

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao; ZHU Hui; ZHENG Hou-Zhi; XU Ping; PENG Hong-Ling; TAN Ping-Heng; YANG Fu-Hua; NI Hai-Qiao; ZENG Yu-Xin; GAN Hua-Dong

    2005-01-01

    @@ We have Fabricated a resonant-cavity-enhanced photodiode (RCE-PD) with InGaAs quantum dots (QDs) as an active medium. This sort of QD-embedded RCE-PD is capable of a peak external quantum efficiency of 32%and responsivity of 0.27 A/W at 1.058 μm with a full width at half maximum (FWHM) of 5nm. Angle-resolved photocurrent response eventually proves that with the detection angle changing from 0° to 60°, the peak-current wavelength shifts towards the short wavelength side by 37nm, while the quantum efficiency remains larger than 15%.

  18. Low cost low phase noise PLL controlled push-push VCOs in k- and ka- bands, stabilized by cavity resonator

    OpenAIRE

    Tsvelykh, I. S.; B. A. Kotserzhynskyi

    2016-01-01

    This work demonstrates push-push VCOs in K-band (with second harmonic output at 24 GHz) and in Ka-band (with third harmonic output at 36 GHz), and PLL synthesizers on their basis. Oscillators are stabilized by a rectangular resonant metallic cavity. Output signal power within the frequency tuning range changes in the limits of -11,5 -7,6 dBm and -11,8 -10,9 dBm for 24 GHz and 36 GHz oscillators respectively. Single sideband (SSB) phase noise spectral densities of -91 dBc/Hz for 24 GHz oscilla...

  19. A multi-atom and resonant interaction scheme for quantum state transfer and logical gates between two remote cavities via an optical fibre

    CERN Document Server

    Yin, Z; Yin, Zhang-qi; Li, Fu-li

    2007-01-01

    A system consisting of two single-mode cavities spatially separated and connected by an optical fibre and multi two-level atoms trapped in the cavities is considered. If the atoms resonantly and collectively interact with the local cavity fields but there is no direct interaction between the atoms, we show that an ideal quantum state transfer, and highly reliable quantum swap, entangling and controlled-Z gates can be deterministically realized between the distant cavities. We find that the operation of the state-transfer, and swap, entangling and controlled-Z gates can be greatly speeded up as number of the atoms in the cavities increases. We also notice that the effects of spontaneous emission of atoms and photon leakage out of cavity on the quantum processes can also be greatly diminished in the multi-atom case.

  20. Free convection in a square cavity filled by a porous medium saturated by a nanofluid: Viscous dissipation and radiation effects

    Directory of Open Access Journals (Sweden)

    M. Ghalambaz

    2016-09-01

    Full Text Available The influence of the viscous dissipation and radiation effects on the natural convection heat transfer in a square cavity filled with porous media saturated with a nanofluid is studied. The vertical walls of the cavity are subject to finite temperature difference while the top and bottom walls of the cavity are insulated. The Buongiorno's nanofluid model, incorporating the Brownian motion and thermophoresis effects, is employed. The governing equations, in nondimensional form, are written in the weak form and solved using the finite element method. The influences of viscous dissipation and radiation effects on the concentration distribution of nanoparticles are discussed. The average and local Nusselt numbers are reported for various values of viscous dissipation (Eckert number and radiation effects. The results show that the Nusselt numbers at the hot and cold walls are not equal due to the presence of viscous dissipation effects. The raise of Eckert number decreases the Nusselt number at hot wall, but it increases the Nusselt number at the cold wall. It is also found that the increase of Lewis number enhances the heat transfer in the cavity.

  1. Fano-resonance boosted cascaded field enhancement in a plasmonic nanoparticle-in-cavity nanoantenna array and its SERS application

    CERN Document Server

    Zhu, Zhendong; You, Oubo; Li, Qunqing; Fan, Shoushan

    2015-01-01

    Cascaded optical field enhancement (CFE) can be realized in some specially designed multiscale plasmonic nanostructures, where the generation of extremely strong field at nanoscale volume is crucial for many applications, for example, surface enhanced Raman spectroscopy (SERS). Here, we propose a strategy of realizing a high-quality plasmonic nanoparticle-in-cavity (PIC) nanoantenna array, where strong coupling between a nanoparticle dark mode with a high order nanocavity bright mode can produce Fano resonance at a target wavelength. The Fano resonance can effectively boost the CFE in the PIC, with a field enhancement factor up to 5X10^2. A cost-effective and reliable nanofabrication method is developed with room temperature nanoimprinting lithography to manufacture high-quality PIC arrays. This technique guarantees the generation of only one gold nanoparticle at the bottom of each nanocavity, which is crucial for the generation of the expected CFE. As a demonstration of the performance and application of the...

  2. Treatment of Oral Cavity Squamous Cell Carcinoma With Adjuvant or Definitive Intensity-Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Sher, David J., E-mail: dsher@lroc.harvard.edu [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States); Thotakura, Vijaya [Department of Medical Oncology, Dana-Farber Cancer Institute and Department of Medicine, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Balboni, Tracy A. [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States); Norris, Charles M.; Haddad, Robert I.; Posner, Marshall R.; Lorch, Jochen [Department of Medical Oncology, Dana-Farber Cancer Institute and Department of Medicine, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Goguen, Laura A.; Annino, Donald J. [Department of Surgery, Division of Otolaryngology, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Tishler, Roy B. [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States)

    2011-11-15

    Purpose: The optimal management of oral cavity squamous cell carcinoma (OCSCC) typically involves surgical resection followed by adjuvant radiotherapy or chemoradiotherapy (CRT) in the setting of adverse pathologic features. Intensity-modulated radiation therapy (IMRT) is frequently used to treat oral cavity cancers, but published IMRT outcomes specific to this disease site are sparse. We report the Dana-Farber Cancer Institute experience with IMRT-based treatment for OCSCC. Methods and Materials: Retrospective study of all patients treated at Dana-Farber Cancer Institute for OCSCC with adjuvant or definitive IMRT between August 2004 and December 2009. The American Joint Committee on Cancer disease stage criteria distribution of this cohort included 5 patients (12%) with stage I; 10 patients (24%) with stage II (n = 10, 24%),; 14 patients (33%) with stage III (n = 14, 33%),; and 13 patients (31%) with stage IV. The primary endpoint was overall survival (OS); secondary endpoints were locoregional control (LRC) and acute and chronic toxicity. Results: Forty-two patients with OCSCC were included, 30 of whom were initially treated with surgical resection. Twenty-three (77%) of 30 surgical patients treated with adjuvant IMRT also received concurrent chemotherapy, and 9 of 12 (75%) patients treated definitively without surgery were treated with CRT or induction chemotherapy and CRT. With a median follow-up of 2.1 years (interquartile range, 1.1-3.1 years) for all patients, the 2-year actuarial rates of OS and LRC following adjuvant IMRT were 85% and 91%, respectively, and the comparable results for definitive IMRT were 63% and 64% for OS and LRC, respectively. Only 1 patient developed symptomatic osteoradionecrosis, and among patients without evidence of disease, 35% experienced grade 2 to 3 late dysphagia, with only 1 patient who was continuously gastrostomy-dependent. Conclusions: In this single-institution series, postoperative IMRT was associated with promising LRC

  3. Nonlinear resonance phenomena of a doped fibre laser under cavity-loss modulation: Experimental demonstrations

    Indian Academy of Sciences (India)

    A Ghosh; B K Goswami; R Vijaya

    2010-11-01

    Our experiments with an erbium-doped fibre ring laser (CW, single transverse 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 modulated periodically. 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.

  4. Widely tunable mid-IR femtosecond resonant radiation induced by self-defocusing solitons in a quadratic nonlinear medium

    DEFF Research Database (Denmark)

    Zhou, Binbin; Liu, Xing; Guo, Hairun;

    2016-01-01

    We experimentally observe widely tunable mid-IR femtosecond pulses by resonant radiation, generated by direct three-wave-mixing from a soliton in PPLN. The poling pitch gives a parametrically tunable resonant radiation, a feature absent in Kerr media....

  5. Nanofriction in Cavity Quantum Electrodynamics.

    Science.gov (United States)

    Fogarty, T; Cormick, C; Landa, H; Stojanović, Vladimir M; Demler, E; Morigi, Giovanna

    2015-12-01

    The dynamics of cold trapped ions in a high-finesse resonator results from the interplay between the long-range Coulomb repulsion and the cavity-induced interactions. The latter are due to multiple scatterings of laser photons inside the cavity and become relevant when the laser pump is sufficiently strong to overcome photon decay. We study the stationary states of ions coupled with a mode of a standing-wave cavity as a function of the cavity and laser parameters, when the typical length scales of the two self-organizing processes, Coulomb crystallization and photon-mediated interactions, are incommensurate. The dynamics are frustrated and in specific limiting cases can be cast in terms of the Frenkel-Kontorova model, which reproduces features of friction in one dimension. We numerically recover the sliding and pinned phases. For strong cavity nonlinearities, they are in general separated by bistable regions where superlubric and stick-slip dynamics coexist. The cavity, moreover, acts as a thermal reservoir and can cool the chain vibrations to temperatures controlled by the cavity parameters and by the ions' phase. These features are imprinted in the radiation emitted by the cavity, which is readily measurable in state-of-the-art setups of cavity quantum electrodynamics.

  6. Controllable optical response by modifying the gain and loss of a mechanical resonator and cavity mode in an optomechanical system

    Science.gov (United States)

    Liu, Yu-Long; Wu, Rebing; Zhang, Jing; Özdemir, Şahin Kaya; Yang, Lan; Nori, Franco; Liu, Yu-xi

    2017-01-01

    We theoretically study a strongly driven optomechanical system which consists of a passive optical cavity and an active mechanical resonator. When the optomechanical coupling strength is varied, phase transitions, which are similar to those observed in PT -symmetric systems, are observed. We show that the optical transmission can be controlled by changing the gain of the mechanical resonator and loss of the optical cavity mode. Especially, we find that (i) for balanced gain and loss, optical amplification and absorption can be tuned by changing the optomechanical coupling strength through a control field; (ii) for unbalanced gain and loss, even with a tiny mechanical gain, both optomechanically induced transparency and anomalous dispersion can be observed around a critical point, which exhibits an ultralong group delay. The time delay τ can be optimized by regulating the optomechanical coupling strength through the control field, and it can be improved up to several orders of magnitude (τ ˜2 ms ) compared to that of conventional optomechanical systems (τ ˜1 μ s ). The presence of mechanical gain makes the group delay more robust to environmental perturbations. Our proposal provides a powerful platform to control light transport using a PT -symmetric-like optomechanical system.

  7. A case study on the ELF characterization of the Earth ionosphere cavity: Forecasting the Schumann resonance intensities

    Science.gov (United States)

    Tulunay, Y.; Altuntas, E.; Tulunay, E.; Price, C.; Ciloglu, T.; Bahadirlar, Y.; Senalp, E. T.

    2008-02-01

    Schumann Resonances (SR) are the electromagnetic (EM) phenomena which occur in the cavity formed by the conducting Earth and the ionosphere, with peak mode frequencies close to 8, 14, 20, 26, 32 Hz, etc. [Price, C., Melnikov, A., 2004. Diurnal, seasonal and inter-annual variations in the Schumann resonance parameters. Journal of Atmospheric and Solar-Terrestrial Physics 66, 1179-1185]. The spectral characteristics of the SR modes are defined by their resonant mode amplitudes, center frequencies and half-widths [Price, C., Melnikov, A., 2004. Diurnal, seasonal and inter-annual variations in the Schumann resonance parameters. Journal of Atmospheric and Solar-Terrestrial Physics 66, 1179-1185]. The objective of this work is two fold: (i) to investigate the characteristics of SR parameters obtained at Sarköy in Turkey and (ii) to model the dynamical characteristics of the SR processes by forecasting the first SR mode power values using a neural network (NN) model. The NN model is revised version of the METUNN [Tulunay, Y., Tulunay, E., Senalp, E.T., 2004a. The neural network technique--1: a general exposition. Advances in Space Research 33, 983-987].

  8. Dynamic control of the asymmetric Fano resonance in side-coupled Fabry–Pérot and photonic crystal nanobeam cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Tong; Chau, Fook Siong; Zhou, Guangya, E-mail: mpezgy@nus.edu.sg [Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore); Deng, Jie [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore)

    2015-11-30

    Fano resonance is a prevailing interference phenomenon that stems from the intersection between discrete and continuum states in many fields. We theoretically and experimentally characterize the asymmetric Fano lineshape in side-coupled waveguide Fabry–Pérot and photonic crystal nanobeam cavities. The measured quality-factor of the Fano resonance before tuning is 28 100. A nanoelectromechanical systems bidirectional actuator is integrated seamlessly to control the shape of the Fano resonance through in-plane translations in two directions without sacrificing the quality-factor. The peak intensity level of the Fano resonance can be increased by 8.5 dB from 60 nW to 409 nW while the corresponding dip intensity is increased by 12.8 dB from 1 nW to 18 nW. The maximum recorded quality-factor throughout the tuning procedure is up to 32 500. Potential applications of the proposed structure include enhancing the sensitivity of sensing, reconfigurable nanophotonics devices, and on-chip intensity modulator.

  9. Frequency dependence of the microwave surface resistance of MgB{sub 2} by coaxial cavity resonator

    Energy Technology Data Exchange (ETDEWEB)

    Agliolo Gallitto, A., E-mail: aurelio.agliologallitto@unipa.it [CNISM and Dipartimento di Fisica e Chimica, Università di Palermo, via Archirafi 36, 90123 Palermo (Italy); Camarda, P.; Li Vigni, M. [CNISM and Dipartimento di Fisica e Chimica, Università di Palermo, via Archirafi 36, 90123 Palermo (Italy); Figini Albisetti, A. [EDISON SpA Research and Development Division, Foro Buonaparte 31, 20121 Milano (Italy); Giunchi, G. [Freelance Consultant, via Teodosio 8, 20131 Milano (Italy)

    2014-08-15

    Highlights: • We investigate the microwave properties of a bulk MgB{sub 2} rod 94.3 mm long. • The MgB{sub 2} rod is used as inner conductor of a coaxial cavity. • The mw surface resistance vs. frequency is studied in the range 1–9 GHz. • R{sub s} vs. f curves follow a f{sup n} law, with n decreasing with the temperature. • Deviations from the quadratic law are highlighted at relatively low temperatures. - Abstract: We report on the microwave (mw) properties of a cylindrical MgB{sub 2} rod prepared by the reactive liquid Mg infiltration technology. The MgB{sub 2} rod, 94.3 mm long, is used as inner conductor of a coaxial cavity having a Cu tube as external conductor. By analyzing the resonance curves of the cavity in the different resonant modes and at different temperatures, we have determined the temperature dependence of the mw surface resistance, R{sub s}, of the MgB{sub 2} material, at fixed frequencies, and the frequency dependence of R{sub s}, at fixed temperatures. Our results show that the R{sub s}(f) curves follow a f{sup n} law, where n decreases on increasing the temperature, starting from n≈2, at T=4.2K, down to n≈0.7 at T⩾T{sub c}. The double-gap nature of MgB{sub 2} manifests itself in the presence of a wide low-T tail in the R{sub s}(T) curves, which can be ascribed to the quasiparticles thermally excited through the π gap even at relatively low temperatures.

  10. Linewidth broadening and emission saturation of a resonantly excited quantum dot monitored via an off-resonant cavity mode

    DEFF Research Database (Denmark)

    Ulhaq, A.; Ates, Serkan; Weiler, S.;

    2010-01-01

    We report on the robustness of a detuned mode channel for reading out the relevant s-shell properties of a resonantly excited coupled quantum dot (QD) in a pillar microcavity. The line broadening of the QD s-shell is “monitored” by the mode signal with high conformity to the directly measured QD ...

  11. Fiber ring resonator with nanofiber section for chiral cavity quantum electrodynamics and multimode strong coupling

    CERN Document Server

    Schneeweiss, Philipp; Hoinkes, Thomas; Rauschenbeutel, Arno; Volz, Jürgen

    2016-01-01

    We experimentally realize an optical fiber ring resonator that includes a tapered section with subwavelength-diameter waist. In this section, the guided light exhibits a significant evanescent field which allows for efficient interfacing with optical emitters. A commercial tunable fiber beam splitter provides simple and robust coupling to the resonator. Key parameters of the resonator such as its out-coupling rate, free spectral range, and birefringence can be adjusted. Thanks to the low taper- and coupling-losses, the resonator exhibits an unloaded finesse of F=75+/-1, sufficient for reaching the regime of strong coupling for emitters placed in the evanescent field. The system is ideally suited for trapping ensembles of laser-cooled atoms along the nanofiber section. Based on measured parameters, we estimate that the system can serve as a platform for optical multimode strong coupling experiments. Finally, we discuss the possibilities of using the resonator for applications based on chiral quantum optics.

  12. Analysis of the resonance frequency shift in cylindrical cavities containing a sphere and its prediction based on the Boltzmann-Ehrenfest principle

    DEFF Research Database (Denmark)

    Orozco Santillán, Arturo; Cutanda Henriquez, Vicente

    2008-01-01

    of the cavity due to the presence of the levitated object. The Boltzmann-Ehrenfest principle has been used to obtain an analytical expression for the resonance frequency shift in a cylindrical cavity produced by a small sphere, with kR .... The validity of the Boltzmann-Ehrenfest method has been investigated by means of the Boundary Element Method (BEM) and confirmed with experiments....

  13. Lattice Boltzmann simulation of surface radiation and natural convection in a square cavity with an inner cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Mezrhab, Ahmed; Moussaoui, M A [Laboratoire de Mecanique and Energetique, Departement de Physique, Faculte des Sciences, Universite Mohamed 1, Oujda (Morocco); Naji, H [Universite des Sciences et Technologies de Lille/Polytech' Lille/LML UMR 8107, F-59655 Villeneuve d' Ascq Cedex (France)], E-mail: mezrhab@fso.ump.ma

    2008-06-07

    A numerical study is carried out for conjugate natural convection-surface radiation heat transfer from a heated circular cylinder enclosed in a square cavity. A hybrid scheme with lattice Boltzmann for fluid velocity variables and finite difference for the temperature is used. The vertical walls of the enclosure are cooled with a uniform temperature while the others are adiabatic. Effects of the Rayleigh number, size and location of the heated cylinder and surface emissivities are investigated numerically. The results are reported in terms of isotherms, streamlines and the average Nusselt number. It is found that (i) the radiation exchange standardizes the temperature inside the cavity and produces an increase in the heat transfer, particularly at large Ra, (ii) the heat transfer enhances with increasing cylinder size and/or surface emissivity and (iii) the maximum rate of heat transfer occurs when the cylinder is located at the horizontal median close to the vertical wall.

  14. Pulse chirp increasing pulse compression followed by positive resonant radiation in fibers

    CERN Document Server

    McLenaghan, Joanna

    2016-01-01

    Pulse self-compression followed by the generation of resonant radiation is a well known phenomenon in non-linear optics. Resonant radiation is important as it allows for efficient and tunable wavelength conversion. We vary the chirp of the initial pulse and find in simulations and experiments that a small positive chirp enhances the pulse compression and strongly increases the generation of resonant radiation. This result corroborates previously published simulation results indicating an improved degree of pulse compression for a small positive chirp [1]. It also demonstrates how pulse evolution can be studied without cutting back the fiber.

  15. Theoretical estimates of maximum fields in superconducting resonant radio frequency cavities: Stability theory, disorder, and laminates

    CERN Document Server

    Liarte, Danilo B; Transtrum, Mark K; Catelani, Gianluigi; Liepe, Matthias; Sethna, James P

    2016-01-01

    We review our work on theoretical limits to the performance of superconductors in high magnetic fields parallel to their surfaces. These limits are of key relevance to current and future accelerating cavities, especially those made of new higher-$T_c$ materials such as Nb$_3$Sn, NbN, and MgB$_2$. We summarize our calculations of the so-called superheating field $H_{\\mathrm{sh}}$, beyond which flux will spontaneously penetrate even a perfect superconducting surface and ruin the performance. We briefly discuss experimental measurements of the superheating field, comparing to our estimates. We explore the effects of materials anisotropy and disorder. Will we need to control surface orientation in the layered compound MgB$_2$? Can we estimate theoretically whether dirt and defects make these new materials fundamentally more challenging to optimize than niobium? Finally, we discuss and analyze recent proposals to use thin superconducting layers or laminates to enhance the performance of superconducting cavities. T...

  16. Compact resonantly intra-cavity pumped tunable Ho:Sc2SiO5 laser

    Science.gov (United States)

    Yang, Xiao-tao; Song, En-zhe; Xie, Wen-qiang

    2017-09-01

    A compact intra-cavity pumped low threshold continuous-wave Ho:Sc2SiO5 laser is reported. The characteristics of output wavelength tuning are investigated by use a intra-cavity briefringent (BF) filter. A wavelength tunable range of 140 nm from 2020 to 2160 nm is achieved. For the free-running mode, the laser slope efficiency is 24.8%, when the output central wavelength is 2110 nm. The laser threshold is about 820 mW of incident pump power. With the BF filter, a maximum output power of 870 mW is obtained at the incident pump power of 5 W, corresponding to a slope efficiency of 20.3%. The characteristics of output wavelength verse the crystal temperature are also investigated.

  17. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xuefeng, E-mail: lixfpost@163.com [School of Science, Xi' an University of Post and Telecommunications, Xi' an, 710121 (China); Cao, Guangzhan; Liu, Hongjun [Xi' an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an, 710119 (China)

    2014-04-15

    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.

  19. An Investigation of Cavity Resonance and its Relationship to Store Force and Moment Loading

    Science.gov (United States)

    2011-03-01

    13 2.3.3 Overset Grids . . . . . . . . . . . . . . . . . . . 16 2.4 Signal Processing and Spectral Analysis ...fluctuating flow present in the region of a weapon bay. Additionally, it was common practice to use high ejector forces in order to release the store at high... ejector forces that can be used. Much of the early research in the area of cavity flows focused on the acoustic modes as it related to structural fatigue in

  20. Spot size and Guoy phase invariant telescope for auto-alignment of resonant cavities

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Jong H [Gravitational Wave Research Facility, Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Rabeling, David [Technische Hogeschool Rijswijk, Lange Kleiweg 80, 2288 GK Rijswijk (Netherlands); Gray, Malcolm B [Gravitational Wave Research Facility, Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); McClelland, David E [Gravitational Wave Research Facility, Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Vine, Glenn de [Gravitational Wave Research Facility, Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia)

    2004-03-07

    We present both the theory and an experimental method to accurately set up a Guoy phase telescope, where both the output spot size and orthogonality condition are invariant to distance from the cavity beam waist. We demonstrate that Gaussian spot size measurements can be used as a diagnostic to determine the desired locations of split area photodetectors. The Guoy phase invariance is verified using the tilt-locking technique.

  1. Effect of surface radiation on the breakdown of steady natural convection flows in a square, air-filled cavity containing a centered inner body

    OpenAIRE

    Sun, H; Chénier, Eric; Lauriat, Guy

    2011-01-01

    Abstract The physical model considered in the present numerical work is a square air-filled cavity cooled from below and above, with a heated square body located at the cavity center. The aim is to establish the effects of radiation interchanges amongst surfaces on the transition from steady, symmetric flows about the cavity centerline to complex periodic flows. Owing to the low temperature differences involved (1 K ? ?T ? 5 K), the two-dimensional model is based on the Boussinesq ...

  2. Three-dimensional cavity nanoantennas with resonant-enhanced surface plasmons as dynamic color-tuning reflectors.

    Science.gov (United States)

    Fan, J R; Wu, W G; Chen, Z J; Zhu, J; Li, J

    2017-03-09

    As plasmonic antennas for surface-plasmon-assisted control of optical fields at specific frequencies, metallic nanostructures have recently emerged as crucial optical components for fascinating plasmonic color engineering. Particularly, plasmonic resonant nanocavities can concentrate lightwave energy to strongly enhance light-matter interactions, making them ideal candidates as optical elements for fine-tuning color displays. Inspired by the color mixing effect found on butterfly wings, a new type of plasmonic, multiresonant, narrow-band (the minimum is about 45 nm), high-reflectance (the maximum is about 95%), and dynamic color-tuning reflector is developed. This is achieved from periodic patterns of plasmonic resonant nanocavities in free-standing capped-pillar nanostructure arrays. Such cavity-coupling structures exhibit multiple narrow-band selective and continuously tunable reflections via plasmon standing-wave resonances. Consequently, they can produce a variety of dark-field vibrant reflective colors with good quality, strong color signal and fine tonal variation at the optical diffraction limit. This proposed multicolor scheme provides an elegant strategy for realizing personalized and customized applications in ultracompact photonic data storage and steganography, colorimetric sensing, 3D holograms and other plasmon-assisted photonic devices.

  3. PRODUCTION OF SOUND BY UNSTEADY THROTTLING OF FLOW INTO A RESONANT CAVITY, WITH APPLICATION TO VOICED SPEECH.

    Science.gov (United States)

    Howe, M S; McGowan, R S

    2011-04-01

    An analysis is made of the sound generated by the time-dependent throttling of a nominally steady stream of air through a small orifice into a flow-through resonant cavity. This is exemplified by the production of voiced speech, where air from the lungs enters the vocal tract through the glottis at a time variable volume flow rate Q(t) controlled by oscillations of the glottis cross-section. Voicing theory has hitherto determined Q from a heuristic, reduced complexity 'Fant' differential equation (G. Fant, Acoustic Theory of Speech Production, 1960). A new self-consistent, integro-differential form of this equation is derived in this paper using the theory of aerodynamic sound, with full account taken of the back-reaction of the resonant tract on the glottal flux Q. The theory involves an aeroacoustic Green's function (G) for flow-surface interactions in a time-dependent glottis, so making the problem non-self-adjoint. In complex problems of this type it is not usually possible to obtain G in an explicit analytic form. The principal objective of the paper is to show how the Fant equation can still be derived in such cases from a consideration of the equation of aerodynamic sound and from the adjoint of the equation governing G in the neighbourhood of the 'throttle'. The theory is illustrated by application to the canonical problem of throttled flow into a Helmholtz resonator.

  4. Transitional regimes of natural convection in a differentially heated cubical cavity under the effects of wall and molecular gas radiation

    Science.gov (United States)

    Soucasse, L.; Rivière, Ph.; Soufiani, A.; Xin, S.; Le Quéré, P.

    2014-02-01

    The transition to unsteadiness and the dynamics of weakly turbulent natural convection, coupled to wall or gas radiation in a differentially heated cubical cavity with adiabatic lateral walls, are studied numerically. The working fluid is air with small contents of water vapor and carbon dioxide whose infrared spectral radiative properties are modelled by the absorption distribution function model. A pseudo spectral Chebyshev collocation method is used to solve the flow field equations and is coupled to a direct ray tracing method for radiation transport. Flow structures are identified by means of either the proper orthogonal decomposition or the dynamic mode decomposition methods. We first retrieve the classical mechanism of transition to unsteadiness without radiation, characterized by counter-rotating streamwise-oriented vortices generated at the exit of the vertical boundary layers. Wall radiation through a transparent medium leads to a homogenization of lateral wall temperatures and the resulting transition mechanism is similar to that obtained with perfectly conducting lateral walls. The transition is due to an unstable stratification upstream the vertical boundary layers and is characterized by periodically oscillating transverse rolls of axis perpendicular to the main flow. When molecular gas radiation is accounted for, no periodic solution is found and the transition to unsteadiness displays complex structures with chimneys-like rolls whose axes are again parallel to the main flow. The origin of this instability is probably due to centrifugal forces, as suggested previously for the case without radiation. Above the transition to unsteadiness, at Ra = 3 × 108, it is shown that both wall and gas radiation significantly intensify turbulent fluctuations, decrease the thermal stratification in the core of the cavity, and increase the global circulation.

  5. 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.

  6. Formation of long-lived resonances in hexagonal cavities by strong coupling of superscar modes

    Science.gov (United States)

    Song, Qinghai; Ge, Li; Wiersig, Jan; Cao, Hui

    2013-08-01

    The recent progresses in single crystalline wide bandgap hexagonal disk have stimulated intense research attention on pursuing ultraviolet (UV) laser diodes with low thresholds. While whispering-gallery modes based UV lasers have been successfully obtained in GaN, ZnO nanorods, and nanopillars, the reported thresholds are still very high, due to the low-quality (Q) factors of the hexagonal resonances. Here we demonstrate resonances whose Q factors can be more than two orders of magnitude higher than the hexagonal modes, promising the reduction of the energy consumption. The key to our finding is the avoided resonance crossing between superscar states along two sets of nearly degenerated triangle orbits, which leads to the formation of hexagram modes. The mode couplings suppress the field distributions at the corners and the deviations from triangle orbits simultaneously and therefore enhance the Q factors significantly.

  7. Two-Qubit Geometric Phase Gate for Quantum Dot Spins using Cavity Polariton Resonance

    CERN Document Server

    Puri, Shruti; Yamamoto, Yoshihisa

    2012-01-01

    We describe a design to implement a two-qubit geometric phase gate, by which a pair of electrons confined in adjacent quantum dots are entangled. The entanglement is a result of the Coulomb exchange interaction between the optically excited exciton-polaritons and the localized spins. This optical coupling, resembling the electron-electron Ruderman-Kittel-Kasuya-Yosida (RKKY) inter- actions, offers high speed, high fidelity two-qubit gate operation with moderate cavity quality factor Q. The errors due to the finite lifetime of the polaritons can be minimized by optimizing the optical pulse parameters (duration and energy). The proposed design, using electrostatic quantum dots, maximizes entanglement and ensures scalability.

  8. Study of thermal conductivity of magnetorheological fluids using the thermal-wave resonant cavity and its relationship with the viscosity

    Science.gov (United States)

    Forero-Sandoval, I. Y.; Vega-Flick, A.; Alvarado-Gil, J. J.; Medina-Esquivel, R. A.

    2017-02-01

    The thermal conductivity and viscosity of a magnetorheological suspension composed of carbonyl iron particles immerse in silicone oil were studied. Thermal wave resonant cavity was employed to measure the thermal diffusivity of the magnetorheological fluid as a function of an externally applied magnetic field. The dynamic viscosity was also measured and its relationship with the concentration of the particles and the magnetic field strength was investigated. The results show that higher concentrations of carbonyl iron particles as well as higher magnetic field intensities lead to a significant increase in thermal conductivity. The relationship between the thermal conductivity and the dynamic viscosity was explored. Our measurements were examined using an analytical relation between the thermal conductivity and the dynamic viscosity. The results show that by using highly viscous materials, the order induced in the micro particles can be kept for a relatively long time and therefore the increase in thermal conductivity can also be maintained.

  9. Design of resonant cavity structure for efficient high-temperature operation of single-photon avalanche photodiodes.

    Science.gov (United States)

    Zavvari, Mahdi; Abedi, Kambiz; Karimi, Mohammad

    2014-05-20

    A novel design of a single-photon avalanche photodiode (SPAD) is proposed based on resonant cavity (RC) structure, and its performance is studied. In the proposed structure, InAlAs/InGaAs distributed Bragg reflectors (DBRs) are employed as top and bottom mirrors and the quantum efficiency (QE) of the absorption region is calculated considering the effect of the RC. Results show that using 12 periods of DBRs as a bottom reflector without incorporation of a top mirror can enhance the QE to about 90% at room temperature. For this RC-enhanced SPAD, a single-photon quantum efficiency (SPQE) is obtained of about 0.35 at T=300  K. For temperatures lower than T=260  K, SPQE is about 1. Results show that although the RC doesn't affect the dark current, for a given SPQE the dark count rate is lower for the RC-SPAD.

  10. Simulation of Coherent Diffraction Radiation Generation by Pico-Second Electron Bunches in an Open Resonator

    Science.gov (United States)

    Sukhikh, L. G.; Potylitsyn, A. P.; Verigin, D. A.

    2016-07-01

    In this report we present new approach for calculation of processes of diffraction radiation generation, storage and decay in an open resonator based on generalized surface current method. The radiation characteristics calculated using the developed approach were compared with those calculated using Gaussian-Laguerre modes method. The comparison shows reasonable coincidence of the results that allows to use developed method for investigation of more complicated resonators.

  11. Generation of linearly polarized resonant transition radiation X-ray beam

    Energy Technology Data Exchange (ETDEWEB)

    Yajima, Kazuaki; Awata, Takaaki; Ikeda, Mitsuharu; Ikeda, Kenichi; Yogo, Akifumi; Itoh, Akio; Imanishi, Nobutsugu [Kyoto Univ. (Japan). Dept. of Nuclear Engineering

    2000-03-01

    We have proposed a method to generate almost linearly polarized resonant transition radiation X rays by using a rectangular slit placed on an electron beam axis. Our calculation predicted that the linearity is 93.5% for the resonant transition radiation X-ray beam extracted through a slit of 0.5 mrad long and 0.2 mrad wide in case of 1-GeV electron beam irradiating a 7.5-{mu}m thick Kapton foil stack. (author)

  12. Electromagnetic wave properties of polymer blends of single wall carbon nanotubes using a resonant microwave cavity as a probe

    Science.gov (United States)

    Roberts, J. A.; Imholt, T.; Ye, Z.; Dyke, C. A.; Price, D. W.; Tour, J. M.

    2004-04-01

    A resonant microwave cavity operating in the TM010 mode was used to determine the microwave susceptibility of single walled carbon nanotubes (SWNT) that are blended in polymer matricies. The frequencies of the probe signal were 9.8, 11.4, and 35.93 GHz. Samples of 3%-19% blends of SWNT in polycarbonate were tested to determine the best blends for shielding of devices from microwaves at these frequencies. It appears that blends of 9%-11% are very effective in shielding the electric vector of electromagnetic waves. Both the electric vector and the magnetic vectors were probed by the process to determine the nature of coupling between the SWNTs and the applied fields. Some details are given about the apparatus design that enables computer collection and processing of the data to be achieved. An electronic differentiation technique was used to allow the second derivative of the cavity absorption profile to be displayed for precise measurement. Data are presented to show the relative microwave absorption for different blends of the SWNTs with polycarbonates.

  13. Cavity quantum electrodynamics using a near-resonance two-level system: Emergence of the Glauber state

    Energy Technology Data Exchange (ETDEWEB)

    Sarabi, B.; Ramanayaka, A. N. [Laboratory for Physical Sciences, College Park, Maryland 20740 (United States); Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Burin, A. L. [Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States); Wellstood, F. C. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Joint Quantum Institute, University of Maryland, College Park, Maryland 20742 (United States); Osborn, K. D. [Laboratory for Physical Sciences, College Park, Maryland 20740 (United States); Joint Quantum Institute, University of Maryland, College Park, Maryland 20742 (United States)

    2015-04-27

    Random tunneling two-level systems (TLSs) in dielectrics have been of interest recently because they adversely affect the performance of superconducting qubits. The coupling of TLSs to qubits has allowed individual TLS characterization, which has previously been limited to TLSs within (thin) Josephson tunneling barriers made from aluminum oxide. Here, we report on the measurement of an individual TLS within the capacitor of a lumped-element LC microwave resonator, which forms a cavity quantum electrodynamics (CQED) system and allows for individual TLS characterization in a different structure and material than demonstrated with qubits. Due to the reduced volume of the dielectric (80 μm{sup 3}), even with a moderate dielectric thickness (250 nm), we achieve the strong coupling regime as evidenced by the vacuum Rabi splitting observed in the cavity spectrum. A TLS with a coherence time of 3.2 μs was observed in a film of silicon nitride as analyzed with a Jaynes-Cummings spectral model, which is larger than seen from superconducting qubits. As the drive power is increased, we observe an unusual but explicable set of continuous and discrete crossovers from the vacuum Rabi split transitions to the Glauber (coherent) state.

  14. Cavity quantum electrodynamics using a near-resonance two-level system: Emergence of the Glauber state

    Science.gov (United States)

    Sarabi, B.; Ramanayaka, A. N.; Burin, A. L.; Wellstood, F. C.; Osborn, K. D.

    2015-04-01

    Random tunneling two-level systems (TLSs) in dielectrics have been of interest recently because they adversely affect the performance of superconducting qubits. The coupling of TLSs to qubits has allowed individual TLS characterization, which has previously been limited to TLSs within (thin) Josephson tunneling barriers made from aluminum oxide. Here, we report on the measurement of an individual TLS within the capacitor of a lumped-element LC microwave resonator, which forms a cavity quantum electrodynamics (CQED) system and allows for individual TLS characterization in a different structure and material than demonstrated with qubits. Due to the reduced volume of the dielectric (80 μm3), even with a moderate dielectric thickness (250 nm), we achieve the strong coupling regime as evidenced by the vacuum Rabi splitting observed in the cavity spectrum. A TLS with a coherence time of 3.2 μs was observed in a film of silicon nitride as analyzed with a Jaynes-Cummings spectral model, which is larger than seen from superconducting qubits. As the drive power is increased, we observe an unusual but explicable set of continuous and discrete crossovers from the vacuum Rabi split transitions to the Glauber (coherent) state.

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

    Science.gov (United States)

    Billet, M.; Latzel, P.; Pavanello, F.; Ducournau, G.; Lampin, J.-F.; Peytavit, E.

    2016-10-01

    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.

  16. 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.

  17. Theoretical estimates of maximum fields in superconducting resonant radio frequency cavities: stability theory, disorder, and laminates

    Science.gov (United States)

    Liarte, Danilo B.; Posen, Sam; Transtrum, Mark K.; Catelani, Gianluigi; Liepe, Matthias; Sethna, James P.

    2017-03-01

    Theoretical limits to the performance of superconductors in high magnetic fields parallel to their surfaces are of key relevance to current and future accelerating cavities, especially those made of new higher-T c materials such as Nb3Sn, NbN, and MgB2. Indeed, beyond the so-called superheating field {H}{sh}, flux will spontaneously penetrate even a perfect superconducting surface and ruin the performance. We present intuitive arguments and simple estimates for {H}{sh}, and combine them with our previous rigorous calculations, which we summarize. We briefly discuss experimental measurements of the superheating field, comparing to our estimates. We explore the effects of materials anisotropy and the danger of disorder in nucleating vortex entry. Will we need to control surface orientation in the layered compound MgB2? Can we estimate theoretically whether dirt and defects make these new materials fundamentally more challenging to optimize than niobium? Finally, we discuss and analyze recent proposals to use thin superconducting layers or laminates to enhance the performance of superconducting cavities. Flux entering a laminate can lead to so-called pancake vortices; we consider the physics of the dislocation motion and potential re-annihilation or stabilization of these vortices after their entry.

  18. Multi circular-cavity surface coil for magnetic resonance imaging of monkey's brain at 4 Tesla

    Science.gov (United States)

    Osorio, A. I.; Solis-Najera, S. E.; Vázquez, F.; Wang, R. L.; Tomasi, D.; Rodriguez, A. O.

    2014-11-01

    Animal models in medical research has been used to study humans diseases for several decades. The use of different imaging techniques together with different animal models offers a great advantage due to the possibility to study some human pathologies without the necessity of chirurgical intervention. The employ of magnetic resonance imaging for the acquisition of anatomical and functional images is an excellent tool because its noninvasive nature. Dedicated coils to perform magnetic resonance imaging experiments are obligatory due to the improvement on the signal-to-noise ratio and reduced specific absorption ratio. A specifically designed surface coil for magnetic resonance imaging of monkey's brain is proposed based on the multi circular-slot coil. Numerical simulations of the magnetic and electric fields were also performed using the Finite Integration Method to solve Maxwell's equations for this particular coil design and, to study the behavior of various vector magnetic field configurations and specific absorption ratio. Monkey's brain images were then acquired with a research-dedicated magnetic resonance imaging system at 4T, to evaluate the anatomical images with conventional imaging sequences. This coil showed good quality images of a monkey's brain and full compatibility with standard pulse sequences implemented in research-dedicated imager.

  19. Resonant enhancement of the zero-phonon emission from a color center in a diamond cavity

    CERN Document Server

    Faraon, Andrei; Santori, Charles; Fu, Kai-Mei C; Beausoleil, Raymond G

    2010-01-01

    We demonstrate coupling of the zero-phonon line of individual nitrogen-vacancy centers and the modes of microring resonators fabricated in single-crystal diamond. A zero-phonon line enhancement exceeding ten-fold is estimated from lifetime measurements at cryogenic temperatures. The devices are fabricated using standard semiconductor techniques and off-the-shelf materials, thus enabling integrated diamond photonics.

  20. Influence of external magnetic and laser radiation fields on Feshbach resonances in collision of atoms

    CERN Document Server

    Gazazyan, E A; Chaltykyan, V O

    2012-01-01

    We study collision of two atoms with formation of Feshbach resonance at combined interaction with the external magnetic field and laser radiation. In cases of one- and two-photon resonances of laser radiation with two discrete vibrational molecular levels, we show that Feshbach resonances appear at interaction of external magnetic field with dressed states formed via Autler-Townes effect. In addition, in case of one-photon resonance the lower vibrational molecular state is coupled by laser radiation with the continuum of the elastic channel and forms laser-induced Feshbach resonance via both Autler-Townes effect and LICS mechanism. We study the combined process of formation of Feshbach resonances; this enables the control of Feshbach resonance by varying the magnetic field and intensity and frequency of laser radiation. We obtain the cross-sections of elastic and inelastic scattering and show that quenching of resonance occurs at the energy equal to that of the systems ground state. Dependence of the cross-se...

  1. Theory of Optical Leaky-Wave Antenna Integrated in a Ring Resonator for Radiation Control

    CERN Document Server

    Guclu, Caner; Capolino, Filippo

    2015-01-01

    The integration of a leaky-wave antenna with a ring resonator is presented using analytical guided wave models. The device consists of a ring resonator fed by a directional coupler, where the ring resonator path includes a leaky-wave antenna segment. The resonator integration provides two main advantages: the high-quality factor ensures effective control of radiation intensity by controlling the resonance conditions and the efficient radiation from a leaky-wave antenna even when its length is much smaller than the propagation length of the leaky wave. We devise an analytical model of the guided wave propagation along a directional coupler and the ring resonator path including the antenna and non-radiating segments. The trade-offs regarding the quality factor of resonance and the antenna efficiency of such a design is reported in terms of the coupler parameters, leaky-wave constant and radiation length. Finally a CMOS-compatible OLWA design suitable for the ring resonator integration is designed where Silicon ...

  2. Dynamics of spontaneous radiation of atoms scattered by a resonance standing light wave

    NARCIS (Netherlands)

    Fedorov, MV; Efremov, MA; Yakovlev, VP; Schleich, WP

    2003-01-01

    The scattering of atoms by a resonance standing light wave is considered under conditions when the lower of two resonance levels is metastable, while the upper level rapidly decays due to mainly spontaneous radiative transitions to the nonresonance levels of an atom. The diffraction scattering regim

  3. Radiation-Tolerant Vertical-Cavity Amplifying Detectors for Time-of-Flight Laser Rangefinders Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The harsh radiation environment anticipated during the Europa Jupiter System Mission (EJSM) presents a significant challenge to develop radiation-hardened notional...

  4. Evaluation of depth and profile cavity after laser ablation with different energy of Er:YAG laser radiation

    Science.gov (United States)

    Dostalova, Tatjana; Jelinkova, Helena; Hamal, Karel; Krejsa, Otakar; Kubelka, Jiri; Prochazka, Stanislav

    1996-01-01

    Depth and profile cavity were studied after laser ablation with different energy of Er:YAG laser beam. Longitudinal sections of extracted human teeth were cut and polished to the flat surfaces. The thickness of layer of prepared teeth was from 3 to 5 mm. The check group contained glazed samples of ivory with the similar thickness. The Er:YAG laser drilling machine was operating in a free-running mode. For the preparation we used the energy up to 500 mJ. The repetition rate was 1 or 2 Hz. The laser radiation was focused on the tooth surface using CaF2 lens (f equals 55 mm). During the experiment, teeth were steady and the radiation was delivered by the mechanical arm which was fixed in a special holder. The fine water mist (water - 50 ml/min with the pressure to atm, air-pressure three atm) was used. Samples with the flat surfaces from the enamel, dentin and ivory were irradiated with five different energies from 100 to 500 mJ. Quantities of one, five, ten, twenty and thirty pulses were used. The depth of cavity and its profile were observed and measured. It was found that depth of cavity depends on the value of energy, type of hard dental tissue and number of pulses. With increasing energy or number of pulses the saturation effect in depth of holes in dentine or enamel were proved.

  5. Bounce resonance scattering of radiation belt electrons by H+ band EMIC waves

    Science.gov (United States)

    Cao, Xing; Ni, Binbin; Summers, Danny; Bortnik, Jacob; Tao, Xin; Shprits, Yuri Y.; Lou, Yuequn; Gu, Xudong; Fu, Song; Shi, Run; Xiang, Zheng; Wang, Qi

    2017-02-01

    We perform a detailed analysis of bounce-resonant pitch angle scattering of radiation belt electrons due to electromagnetic ion cyclotron (EMIC) waves. It is found that EMIC waves can resonate with near-equatorially mirroring electrons over a wide range of L shells and energies. H+ band EMIC waves efficiently scatter radiation belt electrons of energy >100 keV from near 90° pitch angles to lower pitch angles where the cyclotron resonance mechanism can take over to further diffuse electrons into the loss cone. Bounce-resonant electron pitch angle scattering rates show a strong dependence on L shell, wave normal angle distribution, and wave spectral properties. We find distinct quantitative differences between EMIC wave-induced bounce-resonant and cyclotron-resonant diffusion coefficients. Cyclotron-resonant electron scattering by EMIC waves has been well studied and found to be a potentially crucial electron scattering mechanism. The new investigation here demonstrates that bounce-resonant electron scattering may also be very important. We conclude that bounce resonance scattering by EMIC waves should be incorporated into future modeling efforts of radiation belt electron dynamics.

  6. Influence of Intrinsic Decoherence on Entanglement of Superconducting Charge Qubit in a Resonant Cavity

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-Nan; SHAO Bin; ZOU Jian

    2005-01-01

    @@ Taking the intrinsic decoherence effect into account, we investigate the entanglement dynamics of a superconducting charge qubit in a single-mode optical cavity. Concurrence, as the measure of entanglement of the coupled field-junction system, is calculated. In comparison, we also consider the entanglement of the system by using the entanglement parameter based on the ratio between mutual entropy and partial Von-Neumann entropy to investigate how the intrinsic decoherence affects the entanglement of the coupling system. Our results show that the evolution of the entanglement parameter has the behaviour similar to the concurrence and it is thus the well measure of entanglement for the mixed state in such a coupling system.

  7. Optimization of a hot-cavity type resonant ionization laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Henares, J. L., E-mail: henares@ganil.fr; Lecesne, N.; Hijazi, L.; Bastin, B.; Leroy, R.; Osmond, B.; Vignet, J. L. [GANIL, BP 55027, 14076 Caen Cedex 5 (France); Kron, T.; Naubereit, P.; Wendt, K. [Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, 55099 Mainz (Germany); Lassen, J. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Le Blanc, F. [IPN Orsay, BP 1-91406 Orsay (France)

    2016-02-15

    Resonant Ionization Laser Ion Source (RILIS) is nowadays an important technique in many Radioactive Ion Beam (RIB) facilities for its reliability and ability to ionize efficiently and element selectively. Grand Accélérateur National d’Ions Lourds (GANIL) Ion Source using Electron Laser Excitation (GISELE) is an off-line test bench for RILIS developed to study a fully operational resonant laser ion source at GANIL facility. The ion source body has been designed as a modular system to investigate different experimental approaches by varying the design parameters, to develop the future on-line laser ion source. 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. Latest results concerning emittance and time profile development as a function of the temperature for different ion source versions will be presented.

  8. Monolithic white LED based on AlxGa1-x N/InyGa1-yN DBR resonant-cavity

    Science.gov (United States)

    Yu, Chen; Lirong, Huang; Shanshan, Zhu

    2009-01-01

    A monolithic white light-emitting diode (LED) with blue and yellow light active regions has been designed and studied. With the AlxGa1-xN/InyGa1-yN distributed Bragg reflector (DBR) resonant-cavity, the extraction efficiency and power of the yellow light are enhanced so that high quality white light can be obtained.

  9. AlxGa1-xN/InyGa1-yN DBR resonant-cavity based monolithic white LED

    Science.gov (United States)

    Chen, Yu; Huang, Lirong; Zhu, Shanshan

    2008-12-01

    A monolithic white light-emitting diode (LED) with blue and yellow light active regions has been designed and studied. With the AlxGa1-xN / InyGa1-yN distributed Bragg reflector (DBR) resonant-cavity, the extraction efficiency and power of the yellow light are enhanced so that high quality white light can be obtained.

  10. Diagnostic value of magnetic resonance lymphography in preoperative staging of clinically negative necks in squamous cell carcinoma of the oral cavity: A pilot study

    NARCIS (Netherlands)

    Wensing, B.M.; Deserno, W.M.L.L.G.; Bondt, R.B. de; Marres, H.A.M.; Merkx, M.A.W.; Barentsz, J.O.; Hoogen, F.J. van den

    2011-01-01

    Pilot study evaluating the diagnostic value of magnetic resonance lymphography (MRL) compared with conventional imaging techniques in the preoperative staging of the clinically (palpable) negative neck (cN0) in squamous cell carcinoma of the oral cavity (SCCOC). Patients with SCCOC without clinical

  11. Evaluation of Er:YAG laser radiation cavity preparation under transmitted and polarized light and by electron microanalyser

    Science.gov (United States)

    Dostalova, Tatjana; Krejsa, Otakar; Rokytova, Kveta; Jelinkova, Helena; Hamal, Karel

    1993-12-01

    The results of evaluation of Er:YAG radiation cavity preparation under transmitted and polarized light and by the electron microanalyzer are presented. We examined the longitudinal sections of intact teeth, teeth with early dental caries, teeth with laser preparation in enamel and teeth with Er:YAG laser preparation in enamel and dentine class I and V. We examined intact teeth and laser prepared teeth for the variation of mineralization. Phosphorus and calcium were regularly distributed. The margins of cavities had no necrosis zones. The defects of mineralization in caries depend on demineralization of hard tissues. In the structures was irregular loss of calcium and phosphorus. Thus, Er:YAG laser irradiation with water cooling has been found to be a non-invasive preparation technique.

  12. Further Insight Relative to Cavity Radiation: A Thought Experiment Refuting Kirchhoff's Law (Letters to Progress in Physics

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2014-01-01

    Full Text Available Kirchhoff’s law of thermal emission demands that all cavities contain blackbody, or normal, radiation which is dependent solely on the temperature and the frequency of observation, while remaining independent of the nature of t he enclosure. For over 150 years, this law has stood as a great pillar for those who believe that gaseous stars could emit a blackbody spectrum. However, it is well-known that, u nder laboratory condi- tions, gases emit in bands and cannot produce a thermal spectrum. Furthermore, all laboratory blackbodies are constructed from nearly ideal a bsorbers. This fact strongly opposes the validity of Kirchhoff’s formulation. Clearly, if Kirchhoff had been correct, then laboratory blackbodies could be constructed of any arbitrary material. Through the use of two cavities in temperature equilibrium with one another, a thought experiment is presented herein which soundly refutes Kirchhoff’s law of thermal emission.

  13. All-solid-state ultraviolet laser based on frequency doubling in an external ring cavity

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An all-solid-state ultraviolet laser based on frequency doubling in an external ring cavity with low input pump power is reported. Both second harmonic generation (SHG) and fourth harmonic generation (FHG) occurred in an external threemirrors ring cavity. The need for impedance matching of this cavity to the input radiation was eliminated and the cavity adaptation was simplified, because the mirrors were not highly reflecting at 1064 nm and the cavity resonates only at 532 nm. Experiment results demonstrate that the conversion efficiency of this external cavity is higher than that of the singlepass condition.

  14. An exploration in acoustic radiation force experienced by cylindrical shells via resonance scattering theory.

    Science.gov (United States)

    Rajabi, Majid; Behzad, Mehdi

    2014-04-01

    In nonlinear acoustic regime, a body insonified by a sound field is known to experience a steady force that is called the acoustic radiation force (RF). This force is a second-order quantity of the velocity potential function of the ambient medium. Exploiting the sufficiency of linear solution representation of potential function in RF formulation, and following the classical resonance scattering theorem (RST) which suggests the scattered field as a superposition of the resonant field and a background (non-resonant) component, we will show that the radiation force is a composition of three components: background part, resonant part and their interaction. Due to the nonlinearity effects, each part contains the contribution of pure partial waves in addition to their mutual interaction. The numerical results propose the residue component (i.e., subtraction of the background component from the RF) as a good indicator of the contribution of circumferential surface waves in RF. Defining the modal series of radiation force function and its components, it will be shown that within each partial wave, the resonance contribution can be synthesized as the Breit-Wigner form for adequately none-close resonant frequencies. The proposed formulation may be helpful essentially due to its inherent value as a canonical subject in physical acoustics. Furthermore, it may make a tunnel through the circumferential resonance reducing effects on radiation forces.

  15. Observation of soliton-induced resonant radiation due to three-wave mixing

    CERN Document Server

    Zhou, B; Guo, H R; Zeng, X L; Chen, X F; Chung, H P; Chen, Y H; Bache, M

    2016-01-01

    We show experimental proof that three-wave mixing can lead to formation of resonant radiation when interacting with a temporal soliton. This constitutes a new class of resonant waves, and due to the parametric nature of the three-wave mixing nonlinearity, the resonant radiation frequencies are widely tunable over broad ranges in the visible and mid-IR. The experiment is conducted in a periodically poled lithium niobate crystal, where a femtosecond self-defocusing soliton is excited in the near-IR, and resonant radiation due to the sum- and difference-frequency generation quadratic nonlinear terms are observed in the near- and mid-IR, respectively. Their spectral positions are widely tunable by changing the poling pitch and are in perfect agreement with theoretical calculations.

  16. Resonant electron diffusion as a saturation process of the synchrotron maser instability. [of auroral kilometric radiation

    Science.gov (United States)

    Lee, M. C.; Kuo, S. P.

    1986-01-01

    The theory of resonant electron diffusion as an effective saturation process of the auroral kilometric radiation has been formulated. The auroral kilometric radiation is assumed to be amplified by the synchrotron maser instability that is driven by an electron distribution of the loss-cone type. The calculated intensity of the saturated radiation is found to have a significantly lower value in comparison with that caused by the quasi-linear diffusion process as an alternative saturation process. This indicates that resonant electron diffusion dominates over quasi-linear diffusion in saturating the synchrotron maser instability.

  17. Hypofractionated Radiation Therapy Followed by Surgery in Treating Patients With Advanced Squamous Cell Carcinoma of the Oral Cavity

    Science.gov (United States)

    2017-01-19

    Stage III Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage III Verrucous Carcinoma of the Oral Cavity; Stage IVA Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage IVA Verrucous Carcinoma of the Oral Cavity; Stage IVB Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage IVB Verrucous Carcinoma of the Oral Cavity; Tongue Cancer

  18. Standing-wave resonances in plasmonic nanoumbrella cavities for color generation and colorimetric refractive index sensor

    Science.gov (United States)

    Fan, Jiaorong; Li, Zhongyuan; Chen, Zhuojie; Wu, Wengang

    2016-10-01

    We theoretically investigate the hybridization of the elemental surface plasmons in umbrella-shape plasmonic nanostructures and experimentally demonstrate the implementation of plasmonic multicolor metasurfaces as well as their application in colorimetric sensing. The three-dimension metallic umbrella arrays consist of a periodic canopy-capped-nanopillars with metal-coated sidewall and a backplane metal-film to form vertical nanocavity of canopy and film. Plasmonic coupling and energy confinement in nanocavity induce a noticeably resonance narrowing of multispectral reflection. The metasurfaced nanostructures appeared in vibrant and tunable colors with broad gamut derived from color blending mechanism due to multiple, narrow-band resonances. Vivid colors varied from red, yellow, green, blue to violet are easily achieved. It is also shown that such plasmonic metasurfaces can work as the feasible and real-time colorimetric refractive index sensor by measuring the distinct color variation to glucose concentration changes. Our sensor scheme shows its spectral sensitivity in the periodic umbrella array with respect to the refractive index change to be 242.5 nm/RIU with a figure of merit of 7.3. Furthermore, a refractive index resolution of colorimetric sensing up to 0.025 RIU has been accomplished.

  19. Radiation quality factor of spherical antennas with material cores

    DEFF Research Database (Denmark)

    Hansen, Troels Vejle; Kim, Oleksiy S.; Breinbjerg, Olav

    2011-01-01

    This paper gives a description of the radiation quality factor and resonances of spherical antennas with material cores. Conditions for cavity and radiating resonances are given, and a theoretical description of the radiation quality factor, as well as simple expressions describing the relative...

  20. Anomalous response of superconducting titanium nitride resonators to terahertz radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, J., E-mail: j.bueno@sron.nl; Baselmans, J. J. A [SRON, Netherlands Institute of Space Research, Utrecht (Netherlands); Coumou, P. C. J. J.; Zheng, G. [Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Visser, P. J. de [SRON, Netherlands Institute of Space Research, Utrecht (Netherlands); Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Klapwijk, T. M. [Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Physics Department, Moscow State Pedagogical University, 119991 Moscow (Russian Federation); Driessen, E. F. C. [Université Grenoble Alpes, INAC-SPSMS, F-38000 Grenoble (France); CEA, INAC-SPSMS, F-38000 Grenoble (France); Doyle, S. [Cardiff University, School of Physics and Astronomy, Queens Buildings, Cardiff CF24 3AA (United Kingdom)

    2014-11-10

    We present an experimental study of kinetic inductance detectors (KIDs) fabricated of atomic layer deposited TiN films and characterized at radiation frequencies of 350 GHz. The responsivity to radiation is measured and found to increase with the increase in radiation powers, opposite to what is expected from theory and observed for hybrid niobium titanium nitride/aluminium (NbTiN/Al) and all-aluminium (all-Al) KIDs. The noise is found to be independent of the level of the radiation power. The noise equivalent power improves with higher radiation powers, also opposite to what is observed and well understood for hybrid NbTiN/Al and all-Al KIDs. We suggest that an inhomogeneous state of these disordered superconductors should be used to explain these observations.

  1. Non-Destructive Testing for Black Heart Cavities in Potatoes with Microwave Radiation

    CERN Document Server

    Mohamed, Imran; Gregory, Andrew; Mouthaan, Ralf; Tian, Zhengrong; Andrews, Paul; Mellonie, Andrew

    2016-01-01

    A first investigation into the use of microwaves for the non-destructive testing for the presence of black heart cavities is presented. Additionally a potato's complex permittivity data between 0.5 GHz to 20 GHz measured using a coaxial sensor and the recipe for a potato phantom are also presented. Electromagnetic finite-difference time-domain simulations of potatoes show that changes to how microwaves propagate through a potato caused by a cavity can produce measurable changes in S21 at the potato's surface of up to 26 dB. Lab-based readings of the change in S21 caused by a phantom cavity submerged in a potato phantom liquid confirms the results of the simulation, albeit at a much reduced magnitude in the order of 0.1 dB.

  2. Compound cavity theory of resonant phase modulation in laser self-mixing ultrasonic vibration measurement

    Science.gov (United States)

    Tao, Yufeng; Wang, Ming; Guo, Dongmei

    2016-07-01

    The theoretical basis of self-mixing interference (SMI) employing a resonant phase modulator is explored to prove its tempting advantages. The adopted method induces a pure phase carrier without increasing system complexity. A simple time-domain signal process is used to estimate modulation depth and precisely track vibrating trail, which promises the flexibility of measuring ultrasonic vibration regardless of the constraint of the Bessel functions. The broad bandwidth, low speckle noise, compact, safe, and easy operating SMI system obtains the best resolution of a poor reflection environment. Numerical simulation discusses the spectrum broadening and errors due to multiple reflections. Experimental results agree with theory coherently and are compared with laser Doppler vibration meter showing a dynamical error better than 20 nm in ultrasonic vibration measurement.

  3. 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.

  4. Current-voltage characteristic of a resonant tunneling diode under electromagnetic radiation

    Directory of Open Access Journals (Sweden)

    N Hatefi Kargan

    2013-09-01

    Full Text Available  In this paper, current-voltage characteristic of a resonant tunneling diode under electromagnetic radiation has been calculated and compared with the results when there is no electromagnetic radiation. For calculating current -voltage characteristic, it is required to calculate the transmission coefficient of electrons from the well and barrier structures of this device. For calculating the transmission coefficient of electrons at the presence of electromagnetic radiation, Finite Difference Time Domain (FDTD method has been used and when there is no electromagnetic radiation Transfer Matrix Method (TMM and finite diffirence time domain method have been used. The results show that the presence of electromagnetic radiation causes resonant states other than principal resonant state (without presence of electromagnetic radiation to appear on the transmition coefficient curve where they are in distances from the principal peak and from each other. Also, the presence of electromagnetic radiation causes peaks other than principal peak to appear on the current-voltage characteristics of the device. Under electromagnetic radiation, the number of peaks on the current-voltage curve is smaller than the number of peaks on the current-voltage transmission coefficient. This is due to the fact that current-voltage curve is the result of integration on the energy of electrons, Thus, the sharper and low height peaks on the transmission coefficient do not appear on the current-voltage characteristic curve.

  5. Open Microwave Cavity for use in a Purcell Enhancement Cooling Scheme

    CERN Document Server

    Evetts, N; Bizzotto, D; Longuevergne, D; Hardy, W N

    2016-01-01

    A microwave cavity is described which can be used to cool lepton plasmas for potential use in synthesis of antihydrogen. The cooling scheme is an incarnation of the Purcell Effect: when plasmas are coupled to a microwave cavity, the plasma cooling rate is resonantly enhanced through increased spontaneous emission of cyclotron radiation. The cavity forms a three electrode section of a Penning-Malmberg trap and has a bulged cylindrical geometry with open ends aligned with the magnetic trapping axis. This allows plasmas to be injected and removed from the cavity without the need for moving parts while maintaining high quality factors for resonant modes. The cavity includes unique surface preparations for adjusting the cavity quality factor and achieving anti-static shielding using thin layers of nichrome and colloidal graphite respectively. Geometric design considerations for a cavity with strong cooling power and low equilibrium plasma temperatures are discussed. Cavities of this weak-bulge design will be appli...

  6. Parametric excitation of multiple resonant radiations from localized wavepackets

    CERN Document Server

    Conforti, Matteo; Mussot, Arnaud; Kudlinski, Alexandre

    2015-01-01

    Fundamental physical phenomena such as laser-induced ionization, driven quantum tunneling, Faraday waves, Bogoliubov quasiparticle excitations, and the control of new states of matter rely on time-periodic driving of the system. A remarkable property of such driving is that it can induce the localized (bound) states to resonantly couple to the continuum. Therefore experiments that allow for enlightening and controlling the mechanisms underlying such coupling are of paramount importance. We implement such an experiment in a special fiber optics system characterized by a dispersion oscillating along the propagation coordinate, which mimics "time". The quasi-momentum associated with such periodic perturbation is responsible for the efficient coupling of energy from the localized wave-packets sustained by the fiber nonlinearity into free-running linear dispersive waves (continuum), at multiple resonant frequencies. Remarkably, the observed resonances can be explained by means of a unified approach, regardless of ...

  7. Design and Fabrication of 1.06 μm Resonant-Cavity Enhanced Reflective Modulator with GaInAs/GaAs Quantum Wells

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-Hong; HAN Qin; NI Hai-Qiao; HUANG She-Song; DU Yun; PENG Hong-Ling; XIONG Yong-Hua; NIU Zhi-Chuan; WU Rong-Han

    2006-01-01

    A resonant-cavity enhanced reflective optical modulator is designed and fabricated, with three groups of three highly strained InGaAs/GaAs quantum wells in the cavity, for low voltage and high contrast ratio operation.The quantum wells are positioned in antinodes of the optical standing wave. The modulator is grown in a single growth step in an molecular beam epitaxy system, using GaAs/AlAs distributed Bragg reflectors as both the top and bottom mirrors. Results show that the reflection device has a modulation extinction of 3 dB at -4.5 V bias.

  8. Radiation emission from the "Rhodotron-TT200" cavity

    Institute of Scientific and Technical Information of China (English)

    Farshid Tabbakh; Mahmud Borhani

    2011-01-01

    In this paper, the X-rays emitted from the Rhodotron-TT200 cavity have been studied in depth. We found that the Bremsstrahlung interaction is the only contribution of X-ray generation important to safety. The X-ray dose rate in the Rhodotron vault is calc

  9. Electron paramagnetic resonance spectroscopy in radiation research: Current status and perspectives

    Directory of Open Access Journals (Sweden)

    Sudha Rana

    2010-01-01

    Full Text Available Exposure to radiation leads to a number of health-related malfunctions. Ionizing radiation is more harmful than non-ionizing radiation, as it causes both direct and indirect effects. Irradiation with ionizing radiation results in free radical-induced oxidative stress. Free radical-mediated oxidative stress has been implicated in a plethora of diseased states, including cancer, arthritis, aging, Parkinson′s disease, and so on. Electron Paramagnetic Resonance (EPR spectroscopy has various applications to measure free radicals, in radiation research. Free radicals disintegrate immediately in aqueous environment. Free radicals can be detected indirectly by the EPR spin trapping technique in which these forms stabilize the radical adduct and produce characteristic EPR spectra for specific radicals. Ionizing radiation-induced free radicals in calcified tissues, for example, teeth, bone, and fingernail, can be detected directly by EPR spectroscopy, due to their extended stability. Various applications of EPR in radiation research studies are discussed in this review.

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

    Energy Technology Data Exchange (ETDEWEB)

    Henares, J.L., E-mail: henares@ganil.fr [GANIL, BP 55027, 14076 Caen Cedex 5 (France); Lecesne, N.; Hijazi, L.; Bastin, B. [GANIL, BP 55027, 14076 Caen Cedex 5 (France); Kron, T. [Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, 55099 Mainz (Germany); Lassen, J. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada V6T 2A3 (Canada); Le Blanc, F. [IPN Orsay, BP 1-91406 Orsay (France); Leroy, R.; Osmond, B. [GANIL, BP 55027, 14076 Caen Cedex 5 (France); Raeder, S. [Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, 55099 Mainz (Germany); KU Leuven, Oude Markt 13, 3000 Leuven (Belgium); Schneider, F.; Wendt, K. [Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, 55099 Mainz (Germany)

    2016-09-11

    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.

  11. Excitation of the ionospheric resonance cavity by neutral winds at middle latitudes

    Directory of Open Access Journals (Sweden)

    V. V. Surkov

    2004-09-01

    Full Text Available A new mechanism for the ionospheric Alfvén resonator (IAR excitation at middle latitudes is considered. It is shown that the ionosphere wind system in this region is capable of sustaining the generation of geomagnetic perturbations that can be detected by ground magnetometers. The general IAR dispersion relation describing the linear coupling of the shear Alfvén and fast magnetosonic/compressional modes is obtained. The dependence of the IAR eigenfrequencies and damping rates on the perpendicular wave number and on the ground conductivity during the day- and nighttime conditions is analyzed both analytically and numerically. In order to demonstrate the IAR excitation by neutral winds the power spectra of the geomagnetic perturbation on the ground surface are calculated. Furthermore, it is found that Kolmogorov spectra of the ionospheric turbulent neutral winds and the IAR eigenfrequencies lie in the same frequency range that make it possible to enhance the IAR excitation. The relevance of the developed theoretical model to the ground-based observations is stressed.

  12. 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.

    2016-12-01

    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.

  13. 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.

  14. 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.

  15. Resonance-Radiation Force Exerted by a Circularly Polarized Light on an Atomic Wave Packet

    Institute of Scientific and Technical Information of China (English)

    YE Yong-Hua; ZENG Gao-Jian; LI Jin-Hui

    2006-01-01

    We study the behaviour of an atomic wave packet in a circularly polarized light, and especially give the calculation of the radiative force exerted by the circularly polarized light on the atomic wave packet under the resonance condition. A general method of the calculation is presented and the result is interesting. For example, under the condition that the wave packet is very narrow or/and the interaction is very strong, no matter whether the atom is initially in its ground state or excited state, as time approaches to infinity, the resonance-radiation force exerted by the light on the atom approaches to zero. If the atom is initially in its ground state and excited state with the probability 1/2 respectively, and if the momentum density is a even function, then the resonance-radiation force exerted by the light on the atom is equal to zero.

  16. 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.

  17. Retrieving the spatial distribution of cavity modes in dielectric resonators by near-field imaging and electrodynamics simulations.

    Science.gov (United States)

    Goñi, Alejandro R; Güell, Frank; Pérez, Luis A; López-Vidrier, Julian; Ossó, J Oriol; Coronado, Eduardo A; Morante, Joan R

    2012-03-01

    For good performance of photonic devices whose working principle is based on the enhancement of electromagnetic fields obtained by confining light into dielectric resonators with dimensions in the nanometre length scale, a detailed knowledge of the optical mode structure becomes essential. However, this information is usually lacking and can only be indirectly obtained by conventional spectroscopic techniques. Here we unraveled the influence of wire size, incident wavelength, degree of polarization and the presence of a substrate on the optical near fields generated by cavity modes of individual hexagonal ZnO nanowires by combining scanning near-field optical microscopy (SNOM) with electrodynamics calculations within the discrete dipole approximation (DDA). The near-field patterns obtained with very high spatial resolution, better than 50 nm, exhibit striking size and spatial-dispersion effects, which are well accounted for within DDA, using a wavevector-dependent dipolar interaction and considering the dielectric anisotropy of ZnO. Our results show that both SNOM and DDA simulations are powerful tools for the design of optoelectronic devices able to manipulate light at the nanoscale.

  18. Coupled cavity QED for coherent control of photon transmission (II): Slowing light in coupled resonator waveguide doped with $\\Lambda $ Atoms

    CERN Document Server

    Zhou, L; Sun, C P; Lu, Jing; Zhou, Lan

    2006-01-01

    In the first paper of our series of articles on photon transmission in the coupled resonator optical waveguide (CROW), we used the two time Green function approach to study the physical mechanism for the coherent control by doping two-level atoms. In present paper, we propose and study a hybrid mechanism for photon transmission in the CROW by incorporating the electromagnetically induced transparency (EIT) effect in the doping artificial atoms and the band structure of the CROW. Here, the configuration setup of system, similar to that in the first paper, consists of a CROW with homogeneous couplings and the artificial atoms with $\\Lambda$-type three levels doped in each cavity. Unlike the stimulated Raman process used in the first paper to reduce the three level systems into the two level ones, the roles of three levels are completely considered based on a kind of mean field approach where the collection of three-level atoms collectively behave as two-mode spin waves. Then the total system is reduced into an ...

  19. Tuning Leaky Nanocavity Resonances - Perturbation Treatment

    CERN Document Server

    Shlafman, Michael; Salzman, Joseph

    2010-01-01

    Adiabatic frequency tuning of finite-lifetime-nanocavity electromagnetic modes affects also their quality-factor (Q). Perturbative Q change resulting from (real) frequency tuning, is a controllable parameter. Here, the influence of dielectric constant modulation (DCM) on cavity resonances is presented, by first order perturbation analysis for a 3D cavity with radiation losses. Semi-analytical expressions for DCM induced cavity mode frequency and Q changes are derived. The obtained results are in good agreement with numerical calculations.

  20. Using active resonator impedance matching for shot-noise limited, cavity enhanced amplitude modulated laser absorption spectroscopy.

    Science.gov (United States)

    Chow, Jong H; Littler, Ian C M; Rabeling, David S; McClelland, David E; Gray, Malcolm B

    2008-05-26

    We introduce a closed-loop feedback technique to actively control the coupling condition of an optical cavity, by employing amplitude modulation of the interrogating laser. We show that active impedance matching of the cavity facilitates optimal shot-noise sensing performance in a cavity enhanced system, while its control error signal can be used for intra-cavity absorption or loss signal extraction. We present the first demonstration of this technique with a fiber ring cavity, and achieved shot-noise limited loss sensitivity. We also briefly discuss further use of impedance matching control as a tool for other applications.

  1. Dosimetry of ionizing radiations by Electron paramagnetic resonance; Dosimetria de radiaciones ionizantes por resonancia paramagnetica electronica

    Energy Technology Data Exchange (ETDEWEB)

    Azorin N, J. [UAM-I, Av. San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico)

    2005-07-01

    In this work, some historical and theoretical aspects about the Electron Paramagnetic Resonance (EPR), its characteristics, the resonance detection, the paramagnetic species, the radiation effects on inorganic and organic materials, the diagrams of the instrumentation for the EPR detection, the performance of an EPR spectrometer, the coherence among EPR and dosimetry and, practical applications as well as in the food science there are presented. (Author)

  2. Excited atoms in the free-burning Ar arc: treatment of the resonance radiation

    Science.gov (United States)

    Golubovskii, Yu; Kalanov, D.; Gortschakow, S.; Baeva, M.; Uhrlandt, D.

    2016-11-01

    The collisional-radiative model with an emphasis on the accurate treatment of the resonance radiation transport is developed and applied to the free-burning Ar arc plasma. This model allows for analysis of the influence of resonance radiation on the spatial density profiles of the atoms in different excited states. The comparison of the radial density profiles obtained using an effective transition probability approximation with the results of the accurate solution demonstrates the distinct impact of transport on the profiles and absolute densities of the excited atoms, especially in the arc fringes. The departures from the Saha-Boltzmann equilibrium distributions, caused by different radiative transitions, are analyzed. For the case of the DC arc, the local thermodynamic equilibrium (LTE) state holds close to the arc axis, while strong deviations from the equilibrium state on the periphery occur. In the intermediate radial positions the conditions of partial LTE are fulfilled.

  3. From ultraviolet to green InGaN-based conventional and resonant-cavity light-emitting diodes grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Naranjo, F.B.; Fernandez, S.; Calle, F.; Sanchez-Garcia, M.A.; Calleja, E. [ISOM, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria, 28040 Madrid (Spain); Dpto. Ingenieria Electronica, ETSI Telecomunicacion, Universidad Polittecnica de Madrid (Spain)

    2002-08-16

    InGaN/GaN multiple quantum wells grown by molecular beam epitaxy were used as the active layer of standard and resonant-cavity light emitting diodes. Varying the In content in the wells from 1% to 35% and the well thickness from 1 to 2.5 nm, the room temperature electroluminescence can be tuned from 370 nm (ultraviolet) to 510 nm (green). The main factor that determines the emission energy in the well is the exciton localization for narrow wells, whereas for well thicknesses larger than 3 nm the piezoelectric field is the key factor, even for high In contents. Green resonant-cavity light emitting diodes have been successfully fabricated with a semitransparent AlGaN/GaN-based distributed bragg reflector as bottom mirror and an Al coating as top mirror. The external efficiency of those devices is increased by a factor of 10 compared to standard light emitting diodes. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  4. Effect resonance radiation transfer of excitation porous silicon to I sub 2 molecules sorbed in pores

    CERN Document Server

    Zakharchenko, K V; Kuznetsov, M B; Chistyakov, A A; Karavanskij, V A

    2001-01-01

    One studies the effect of resonance radiation-free transfer of electronic excitation between silicon nanocrystals and iodine molecules sorbed in pores. The experiment procedure includes laser-induced luminescence and laser desorption mass spectrometry. One analyzes photoluminescence spectra prior to and upon iodine sorption. Excitation of iodine through the mechanism of resonance transfer is determined to result in desorption of the iodine sorbed molecules with relatively high kinetic energies (3-1 eV). One evaluated the peculiar distance of resonance transfer the approximate value of which was equal to 2 nm

  5. Resonantly Enhanced Multiphoton Ionization under XUV FEL radiation: A case study of the role of harmonics

    CERN Document Server

    Nikolopoulos, Georgios M

    2016-01-01

    We provide a detailed quantitative study of the possible role of a small admixture of harmonics on resonant two-photon ionization. The motivation comes from the occasional presence of 2nd and 3rd harmonics in FEL radiation. We obtain the dependence of ionic yields on the intensity of the fundamental, the percentage of 2nd harmonic and the detuning of the fundamental from resonance. Having examined the cases of one and two intermediate resonances, we arrive at results of general validity and global behavior, showing that even a small amount of harmonic may seem deceptively innocuous.

  6. Stimulated excitation of resonant Cherenkov radiation at a large number of neighbouring waveguide modes

    CERN Document Server

    Grigoryan, L Sh; Khachatryan, H F; Grigoryan, M L

    2012-01-01

    The resonance Cherenkov radiation generated from a train of equally-spaced unidimensional electron bunches travelling along the axis of a hollow channel inside an infinite cylindrical waveguide filled with (weakly dispersing) transparent dielectric has been investigated. It was shown that its excitation might be stimulated at a large number of neighboring modes of the waveguide. A visual explanation of this effect is given and the possibility of its observation in the range of terahertz radiation is discussed.

  7. A micropillar for cavity optomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Aurélien; Neuhaus, Leonhard; Deléglise, Samuel; Briant, Tristan; Cohadon, Pierre-François; Heidmann, Antoine [Laboratoire Kastler Brossel, UPMC-ENS-CNRS, Paris (France); Van Brackel, Emmanuel [Département de Physique, ENS, Paris (France); Chartier, Claude; Ducloux, Olivier; Le Traon, Olivier [Département Mesures Physiques, ONERA, Châtillon (France); Michel, Christophe; Pinard, Laurent; Flaminio, Raffaele [Laboratoire des Matériaux Avancés, IN2P3-CNRS, Lyon (France)

    2014-12-04

    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.

  8. Surface plasmon-polariton resonance at diffraction of THz radiation on semiconductor gratings

    CERN Document Server

    Spevak, I S; Gavrikov, V K; Shulga, V M; Feng, J; Sun, H B; Kamenev, Yu E; Kats, A V

    2013-01-01

    Resonance diffraction of THz HCN laser radiation on a semiconductor (InSb) grating is studied both experimentally and theoretically. The specular reflectivity suppression due to the resonance excitation of the THz surface plasmon-polariton is observed on a pure semiconductor grating and on semiconductor gratings covered with a thin striped layer of the residual photoresist. Presence of a thin dielectric layer on the grating surface leads to the shift and widening of the plasmon-polariton resonance. A simple analytical theory of the resonance diffraction on a shallow grating covered with a dielectric layer is presented. Its results are in a good accordance with the experimental data. Analytical expressions for the resonance shift and broadening can be useful for sensing data interpretation.

  9. Minimisation of the sound power radiated by a submarine through optimisation of its resonance changer

    Science.gov (United States)

    Merz, Sascha; Kessissoglou, Nicole; Kinns, Roger; Marburg, Steffen

    2010-04-01

    An important cause of sound radiation from a submarine in the low frequency range is fluctuating forces at the propeller. The forces are transmitted to the hull via the shaft and the fluid. Sound radiation occurs due to hull and propeller vibrations as well as dipole sound radiation caused by the operation of the propeller in a non-uniform wake. In order to minimise sound radiation caused by propeller forces, a hydraulic vibration attenuation device known as a resonance changer can be implemented in the propeller/shafting system. In this work, cost functions that represent the overall radiated sound power are investigated, where the virtual stiffness, damping and mass of the resonance changer were chosen as design parameters. The minima of the cost functions are found by applying gradient based optimisation techniques. The finite element and boundary element methods are used to model the structure and the fluid, respectively. The adjoint operator is employed to calculate the sensitivity of the cost function to the design parameters. The influence of sound radiation due to propeller vibration on the optimisation of the resonance changer as well as the influence of the reduction in amplitude for higher harmonics of the blade-passing frequency on the control performance is investigated.

  10. Passive Infrared Sensing Using Plasmonic Resonant Dust Particles

    Directory of Open Access Journals (Sweden)

    Mark Mirotznik

    2012-01-01

    Full Text Available We present computational and experimental results of dust particles that can be tuned to preferentially reflect or emit IR radiation within the 8–14 μm band. The particles consist of thin metallic subwavelength gratings patterned on the surface of a simple quarter wavelength cavity. This design creates distinct IR absorption resonances by combining the plasmonic resonance of the grating with the natural resonance of the cavity. We show that the resonance peaks are easily tuned by varying either the geometry of the grating or the thickness of the cavity. Here, we present a computational design algorithm along with experimental results that validate the design methodology.

  11. Resonant and non-resonant whistlers-particle interaction in the radiation belts

    CERN Document Server

    Camporeale, Enrico

    2014-01-01

    We study the wave-particle interactions between lower band chorus whistlers and an anisotropic tenuous population of relativistic electrons. We present the first direct comparison of first-principle Particle-in-Cell (PIC) simulations with a quasi-linear diffusion code, in this context. In the PIC approach, the waves are self-consistently generated by a temperature anisotropy instability that quickly saturates and relaxes the system towards marginal stability. We show that the quasi-linear diffusion and PIC results have significant quantitative mismatch in regions of energy/pitch angle where the resonance condition is not satisfied. Moreover, for pitch angles close to the loss cone the diffusion code overestimates the scattering, particularly at low energies. This suggest that higher order nonlinear theories should be taken in consideration in order to capture non-resonant interactions, resonance broadening, and to account for scattering at angles close to $90^\\circ$.

  12. Photodynamic action of laser radiation and methylene blue on some opportunistic microorganisms of the oral cavity

    Science.gov (United States)

    Ivanov, Krill I.; Titorenko, Vladimir A.; Shoub, Gennady M.; Lepilin, Alexander V.; Ovchinnikov, Ilya S.; Mischenko, Oksana S.; Tuchin, Valery V.

    2000-03-01

    We have studied photodynamic action of He-Ne laser radiation on cultures of Staphylococcus (strain 209 P), Streptococcus anhaemolyticus, and total microflora of dental deposit been sensitized by methylene blue. The concentration of the dye was varied from 0.001% to 0.1%, radiation power density was 100 mW/cm2. Irradiated strain was put into thermostat for 24 hours, then the number of colonies was counted and analyzed.

  13. Superradiant amplification of terahertz radiation by plasmons in inverted graphene with a planar distributed Bragg resonator

    Energy Technology Data Exchange (ETDEWEB)

    Polischuk, O. V., E-mail: polischuk.sfire@mail.ru; Popov, V. V., E-mail: popov-slava@yahoo.co.uk [Russian Academy of Sciences, Saratov Branch, Kotel’nikov Institute of Radioengineering and Electronics (Russian Federation); Otsuji, T. [Tohoku University, Research Institute for Electrical Communication (Japan)

    2015-11-15

    It is shown theoretically that stimulated generation of terahertz radiation by plasmons in graphene with a planar distributed Bragg resonator is possible at two different frequencies for each plasmon mode. This behavior may be attributed to the superradiance of the collective plasmon mode, which is associated with superlinear increase in the radiative damping of the plasmons with increase in pumping power. As a result, the curves of the radiative damping and the plasmon gain as a function of the pumping power intersect at two points corresponding to different generation conditions.

  14. Resonant Transparency and Non-Trivial Non-Radiating Excitations in Toroidal Metamaterials

    Science.gov (United States)

    Fedotov, V. A.; Rogacheva, A. V.; Savinov, V.; Tsai, D. P.; Zheludev, N. I.

    2013-01-01

    Engaging strongly resonant interactions allows dramatic enhancement of functionalities of many electromagnetic devices. However, resonances can be dampened by Joule and radiation losses. While in many cases Joule losses may be minimized by the choice of constituting materials, controlling radiation losses is often a bigger problem. Recent solutions include the use of coupled radiant and sub-radiant modes yielding narrow asymmetric Fano resonances in a wide range of systems, from defect states in photonic crystals and optical waveguides with mesoscopic ring resonators to nanoscale plasmonic and metamaterial systems exhibiting interference effects akin to electromagnetically-induced transparency. Here we demonstrate theoretically and confirm experimentally a new mechanism of resonant electromagnetic transparency, which yields very narrow isolated symmetric Lorentzian transmission lines in toroidal metamaterials. It exploits the long sought non-trivial non-radiating charge-current excitation based on interfering electric and toroidal dipoles that was first proposed by Afanasiev and Stepanovsky in [J. Phys. A Math. Gen. 28, 4565 (1995)]. PMID:24132231

  15. Radiation reaction effect on laser driven auto-resonant particle acceleration

    Science.gov (United States)

    Sagar, Vikram; Sengupta, Sudip; Kaw, P. K.

    2015-12-01

    The effects of radiation reaction force on laser driven auto-resonant particle acceleration scheme are studied using Landau-Lifshitz equation of motion. These studies are carried out for both linear and circularly polarized laser fields in the presence of static axial magnetic field. From the parametric study, a radiation reaction dominated region has been identified in which the particle dynamics is greatly effected by this force. In the radiation reaction dominated region, the two significant effects on particle dynamics are seen, viz., (1) saturation in energy gain by the initially resonant particle and (2) net energy gain by an initially non-resonant particle which is caused due to resonance broadening. It has been further shown that with the relaxation of resonance condition and with optimum choice of parameters, this scheme may become competitive with the other present-day laser driven particle acceleration schemes. The quantum corrections to the Landau-Lifshitz equation of motion have also been taken into account. The difference in the energy gain estimates of the particle by the quantum corrected and classical Landau-Lifshitz equation is found to be insignificant for the present day as well as upcoming laser facilities.

  16. Radiation reaction effect on laser driven auto-resonant particle acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Sagar, Vikram; Sengupta, Sudip; Kaw, P. K. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2015-12-15

    The effects of radiation reaction force on laser driven auto-resonant particle acceleration scheme are studied using Landau-Lifshitz equation of motion. These studies are carried out for both linear and circularly polarized laser fields in the presence of static axial magnetic field. From the parametric study, a radiation reaction dominated region has been identified in which the particle dynamics is greatly effected by this force. In the radiation reaction dominated region, the two significant effects on particle dynamics are seen, viz., (1) saturation in energy gain by the initially resonant particle and (2) net energy gain by an initially non-resonant particle which is caused due to resonance broadening. It has been further shown that with the relaxation of resonance condition and with optimum choice of parameters, this scheme may become competitive with the other present-day laser driven particle acceleration schemes. The quantum corrections to the Landau-Lifshitz equation of motion have also been taken into account. The difference in the energy gain estimates of the particle by the quantum corrected and classical Landau-Lifshitz equation is found to be insignificant for the present day as well as upcoming laser facilities.

  17. Coherent propagation of a short polarised radiation pulse in a one-dimensional resonance Bragg grating

    NARCIS (Netherlands)

    Maimistov, A. I.; Polikarpov, V. V.

    2006-01-01

    The propagation of an optical ultrashort pulse in a resonance Bragg grating is considered taking into account the polarisation of electromagnetic radiation. It is assumed that the grating is formed by thin films containing two-level atoms with the triply degenerate upper energy level. The system of

  18. Optical back-action in silicon nanowire resonators: bolometric versus radiation pressure effects

    Science.gov (United States)

    Gil-Santos, E.; Ramos, D.; Pini, V.; Llorens, J.; Fernández-Regúlez, M.; Calleja, M.; Tamayo, J.; San Paulo, A.

    2013-03-01

    We study optical back-action effects associated with confined electromagnetic modes in silicon nanowire resonators interacting with a laser beam used for interferometric read-out of the nanowire vibrations. Our analysis describes the resonance frequency shift produced in the nanowires by two different mechanisms: the temperature dependence of the nanowire's Young's modulus and the effect of radiation pressure. We find different regimes in which each effect dominates depending on the nanowire morphology and dimensions, resulting in either positive or negative frequency shifts. Our results also show that in some cases bolometric and radiation pressure effects can have opposite contributions so that their overall effect is greatly reduced. We conclude that Si nanowire resonators can be engineered for harnessing back-action effects for either optimizing frequency stability or exploiting dynamic phenomena such as parametric amplification.

  19. Effects of radiation and α-tocopherol on saliva flow rate, amylase activity, total protein and electrolyte levels in oral cavity cancer

    Directory of Open Access Journals (Sweden)

    Chitra S

    2008-01-01

    Full Text Available Objective: The objective of the present study was to evaluate early and late effects of radiation and a-tocopherol on the secretion rate of saliva and on selected saliva salivary parameters in oral cavity cancer patients. Patients & Methods: Eighty-nine histologically confirmed oral cavity cancer patients (OCC were enrolled in the study. Resting whole saliva was collected before, during and at the end of the radiation therapy (RT and simultaneous supplementation with α - tocopherol to the radiation treated patients (RT + AT. Results: Salivary flow rate, pH, amylase activity, total protein, sodium and potassium were analyzed. Increased pH, potassium and decreased flow rate, amylase activity, protein content and sodium were observed in 6 weeks of radiation treated patients when compared to OCC patients. A significant improvement of those parameters was observed on α - tocopherol supplementation in RT + AT patients. Conclusion: Supplementation with α - tocopherol improves the salivary flow rate thereby, maintains salivary parameters.

  20. Resonant behavior of MHD waves on magnetic flux tubes. IV - Total resonant absorption and MHD radiating eigenmodes

    Science.gov (United States)

    Goossens, Marcel; Hollweg, Joseph V.

    1993-01-01

    Resonant absorption of MHD waves on a nonuniform flux tube is investigated as a driven problem for a 1D cylindrical equilibrium. The variation of the fractional absorption is studied as a function of the frequency and its relation to the eigenvalue problem of the MHD radiating eigenmodes of the nonuniform flux tube is established. The optimal frequencies producing maximal fractional absorption are determined and the condition for total absorption is obtained. This condition defines an impedance matching and is fulfilled for an equilibrium that is fine tuned with respect to the incoming wave. The variation of the spatial wave solutions with respect to the frequency is explained as due to the variation of the real and imaginary parts of the dispersion relation of the MHD radiating eigenmodes with respect to the real driving frequency.

  1. Methods of Measuring Lock-In Strength and their Application to the Case of Flow over a Cavity Locking into a Single Side Branch Resonator

    Energy Technology Data Exchange (ETDEWEB)

    Richard S. Mendelson

    2003-04-16

    Lock-in is a non-linear interaction between a flow induced noise source and a resonator when their respective frequencies are near each other. Lock-in has been reported under many different labels and for many different applications. There is a need however for a consistent community wide method to measure the strength of lock-in so that data from different tests and different source/resonator combinations can be compared. This paper discusses three methods for measuring lock-in strength. The first, Resonant Response Method, (RRM) subtracts (in the decibel scale) the linear modal response of the resonator to broadband (BB) flow noise from the resonant response when lock-in occurs. The second, Quality Factor Method (QFM) tracks the change in quality factor of the resonant response. The third defines the strength in terms of the difference between peak response and the local BB levels. The RRM is applied to a fundamental test in water of a weak source from grazing flow over a cavity locking into acoustic resonant modes of a single side branch resonator. The major velocity effects are captured in the resonant response to BB flow and not in lock-in strength. However, Strouhal stage number and modal damping is shown to have a significant impact on strength. For two modes, strength versus flow rate using the RRM is compared to strengths obtained using the QFM; on a decibel scale the results are shown to be within experimental uncertainty. However, the QFM is noticeably more difficult to apply. The author recommends the use of the Resonant Response Method as the most tractable measure of lock-in strength.

  2. Optical characterization and selective addressing of the resonant modes of a micropillar cavity with a white light beam

    NARCIS (Netherlands)

    Ctistis, Georgios; Hartsuiker, Alex; Pol, van der Edwin; Claudon, Julien; Vos, Willem L.; Gérard, Jean-Michel

    2010-01-01

    We have performed white light reflectivity measurements on GaAs/AlAs micropillar cavities with diameters ranging from 1 μm up to 20 μm. We are able to resolve the spatial field distribution of each cavity mode in real space by scanning a small-sized beam across the top facet of each micropillar. We

  3. Resonance effects of transition radiation emitted from thin foil stacks using electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Awata, Takaaki; Yajima, Kazuaki; Tanaka, Takashi [Kyoto Univ. (Japan). Faculty of Engineering] [and others

    1997-03-01

    Transition Radiation(TR) X rays are expected to be a high brilliant X-ray source because the interference among TR X rays emitted from many thin foils placed periodically in vacuum can increase their intensity and make them quasi-monochromatic. In order to study the interference (resonance) effects of TR, we measured the energy spectra of TR for several sets of thin-foil stacks at various emission angles. It was found that the resonance effects of TR are classified into intrafoil and interfoil resonances and the intensity of TR X rays increases nonlinearly with increasing foil number, attributing to the interfoil resonance. It became evident that the brilliance of TR is as high as that of SR. (author)

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

    Science.gov (United States)

    Tarvainen, O; Orpana, J; Kronholm, R; Kalvas, T; Laulainen, J; Koivisto, H; Izotov, I; Skalyga, V; Toivanen, V

    2016-09-01

    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(3+)-O(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.

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

    Science.gov (United States)

    Tarvainen, O.; Orpana, J.; Kronholm, R.; Kalvas, T.; Laulainen, J.; Koivisto, H.; Izotov, I.; Skalyga, V.; Toivanen, V.

    2016-09-01

    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 O3+-O7+ 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.

  6. 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.

  7. The structure of pre-transitional protoplanetary disks. I. Radiative transfer modeling of the disk+cavity in the PDS 70 system

    NARCIS (Netherlands)

    Dong, R.; Hashimoto, J.; Rafikov, R.; Zhu, Z.; Whitney, B.; Kudo, T.; Muto, T.; Brandt, T.; McClure, M.K.; Wisniewski, J.; Abe, L.; Brandner, W.; Carson, J.; Egner, S.; Feldt, M.; Goto, M.; Grady, C.; Guyon, O.; Hayano, Y.; Hayashi, M.; Hayashi, S.; Henning, T.; Hodapp, K.W.; Ishii, M.; Iye, M.; Janson, M.; Kandori, R.; Knapp, G.R.; Kusakabe, N.; Kuzuhara, M.; Kwon, J.; Matsuo, T.; McElwain, M.; Miyama, S.; Morino, J.-I.; Moro-Martin, A.; Nishimura, T.; Pyo, T.-S.; Serabyn, E.; Suto, H.; Suzuki, R.; Takami, M.; Takato, N.; Terada, H.; Thalmann, C.; Tomono, D.; Turner, E.; Watanabe, M.; Yamada, T.; Takami, H.; Usuda, T.; Tamura, M.

    2012-01-01

    Through detailed radiative transfer modeling, we present a disk+cavity model to simultaneously explain both the spectral energy distribution (SED) and Subaru H-band polarized light imaging for the pre-transitional protoplanetary disk PDS 70. In particular, we are able to match not only the radial de

  8. Radiative Emission Enhancement Using Nano-antennas Made of Hyperbolic Metamaterial Resonators

    CERN Document Server

    Guclu, Caner; Wang, George T; Capolino, Filippo

    2014-01-01

    A hyperbolic metamaterial resonator is analyzed as a nano-antenna for enhancing the radiative emission of quantum emitters in its vicinity. It has been shown that the spontaneous emission rate by an emitter near a hyperbolic metamaterial substrate is enhanced dramatically due to very large density of states. However, enhanced coupling to the free-space, which is central to applications such as solid-state lighting, has not been investigated significantly. Here, we numerically demonstrate approximately 100 times enhancement of the free-space radiative emission at 660 nm wavelength by utilizing a cylindrical HM resonator with a radius of 54 nm and a height of 80 nm on top of an opaque silver-cladded substrate. We also show how the free-space radiation enhancement factor depends on the dipole orientation and the location of the emitter near the subwavelength resonator. Furthermore, we calculate that an array of HM resonators with subwavelength spacings can maintain most of the enhancement effect of a single reso...

  9. Radiation Reaction Effect on Laser Driven Auto-Resonant Particle Acceleration

    CERN Document Server

    Sagar, Vikram; Kaw, P K

    2015-01-01

    The effects of radiation reaction force on laser driven auto-resonant particle acceleration scheme are studied using Landau-Lifshitz equation of motion. These studies are carried out for both linear as well as circularly polarized laser fields in the presence of static axial magnetic field. From the parametric study, a radiation reaction dominated region has been identified in which the particle dynamics is greatly effected by this force. In the radiation reaction dominated region the two significant effects on particle dynamics are seen viz., (1) saturation in energy gain by the initially resonant particle, (2) net energy gain by a initially non-resonant particle which is caused due to resonance broadening. It has been further shown that with the optimum choice of parameters this scheme can be efficiently used to produce electrons with energies in the range of hundreds of TeV. The quantum corrections to the Landu-Lifshitz equation of motion have also been taken into account. The difference in the energy gain...

  10. Malignant tumors of the nasal cavity: computed tomography and magnetic resonance imaging; Tumores malignos da cavidade nasal: tomografia computadorizada e ressonancia magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Ricardo Pires de; Paes Junior, Ademar Jose de Oliveira; Gonzalez, Fabio Mota; Cordeiro, Flamarion de Barros; Yamashiro, Ilka [Complexo Hospitalar Heliopolis, Sao Paulo, SP (Brazil). Programa de Residencia Medica em Radiologia e Diagnostico por Imagem]. E-mail: ricapires@ig.com.br; Lenh, Carlos Neutzling [Complexo Hospitalar Heliopolis, Sao Paulo, SP (Brazil). Servico de Cirurgia de Cabeca e Pescoco; Rapoport, Abrao [Complexo Hospitalar Heliopolis, Sao Paulo, SP (Brazil). Curso de Pos-graduacao em Ciencias da Saude

    2004-10-01

    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. 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 Heliopolis', Sao Paulo, Brazil, between 1990 and 2000. All cases were confirmed by histopathologic examination. The results were: 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 nasal pharynx and masticator space in two patients, extension to cavernous sinus, anterior/middle cranial fossa, pterygomaxillary fossa, inferior/superior orbital fissure, frontal sinus, contralateral ethmoid sinus, contralateral lamina cribosa, hard palate and pterygopalatine fossa in one patient. Conclusion: It is important to precisely assess the local extension and spread of tumor by computed tomography and magnetic resonance imaging in order to plan the approach to treatment, which will influence the prognosis. (author)

  11. Predicting the severity and prognosis of trismus after intensity-modulated radiation therapy for oral cancer patients by magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Li-Chun Hsieh

    Full Text Available To develop magnetic resonance imaging (MRI indicators to predict trismus outcome for post-operative oral cavity cancer patients who received adjuvant intensity-modulated radiation therapy (IMRT, 22 patients with oral cancer treated with IMRT were studied over a two-year period. Signal abnormality scores (SA scores were computed from Likert-type ratings of the abnormalities of nine masticator structures and compared with the Mann-Whitney U-test and Kruskal-Wallis one-way ANOVA test between groups. Seventeen patients (77.3% experienced different degrees of trismus during the two-year follow-up period. The SA score correlated with the trismus grade (r = 0.52, p<0.005. Patients having progressive trismus had higher mean doses of radiation to multiple structures, including the masticator and lateral pterygoid muscles, and the parotid gland (p<0.05. In addition, this group also had higher SA-masticator muscle dose product at 6 months and SA scores at 12 months (p<0.05. At the optimum cut-off points of 0.38 for the propensity score, the sensitivity was 100% and the specificity was 93% for predicting the prognosis of the trismus patients. The SA score, as determined using MRI, can reflect the radiation injury and correlate to trismus severity. Together with the radiation dose, it could serve as a useful biomarker to predict the outcome and guide the management of trismus following radiation therapy.

  12. Predicting the severity and prognosis of trismus after intensity-modulated radiation therapy for oral cancer patients by magnetic resonance imaging.

    Science.gov (United States)

    Hsieh, Li-Chun; Chen, John W; Wang, Li-Ying; Tsang, Yuk-Ming; Shueng, Pei-Wei; Liao, Li-Jen; Lo, Wu-Chia; Lin, Yu-Chin; Tseng, Chien-Fu; Kuo, Ying-Shiung; Jhuang, Jie-Yang; Tien, Hui-Ju; Juan, Hsueh-Fen; Hsieh, Chen-Hsi

    2014-01-01

    To develop magnetic resonance imaging (MRI) indicators to predict trismus outcome for post-operative oral cavity cancer patients who received adjuvant intensity-modulated radiation therapy (IMRT), 22 patients with oral cancer treated with IMRT were studied over a two-year period. Signal abnormality scores (SA scores) were computed from Likert-type ratings of the abnormalities of nine masticator structures and compared with the Mann-Whitney U-test and Kruskal-Wallis one-way ANOVA test between groups. Seventeen patients (77.3%) experienced different degrees of trismus during the two-year follow-up period. The SA score correlated with the trismus grade (r = 0.52, ptrismus had higher mean doses of radiation to multiple structures, including the masticator and lateral pterygoid muscles, and the parotid gland (ptrismus patients. The SA score, as determined using MRI, can reflect the radiation injury and correlate to trismus severity. Together with the radiation dose, it could serve as a useful biomarker to predict the outcome and guide the management of trismus following radiation therapy.

  13. Design of optomechanical cavities and waveguides on a simultaneous bandgap phononic-photonic crystal slab.

    Science.gov (United States)

    Safavi-Naeini, Amir H; Painter, Oskar

    2010-07-05

    In this paper we study and design quasi-2D optomechanical crystals, waveguides, and resonant cavities formed from patterned slabs. Two-dimensional periodicity allows for in-plane pseudo-bandgaps in frequency where resonant optical and mechanical excitations localized to the slab are forbidden. By tailoring the unit cell geometry, we show that it is possible to have a slab crystal with simultaneous optical and mechanical pseudo-bandgaps, and for which optical waveguiding is not compromised. We then use these crystals to design optomechanical cavities in which strongly interacting, co-localized photonic-phononic resonances occur. A resonant cavity structure formed by perturbing a ;;linear defect' waveguide of optical and acoustic waves in a silicon optomechanical crystal slab is shown to support an optical resonance at wavelength lambda(0) approximately 1.5 mum and a mechanical resonance of frequency omega(m)/2pi approximately 9.5 GHz. These resonances, due to the simultaneous pseudo-bandgap of the waveguide structure, are simulated to have optical and mechanical radiation-limited Q-factors greater than 10(7). The optomechanical coupling of the optical and acousticresonances in this cavity due to radiation pressure is also studied, with a quantum conversion rate, corresponding to the scattering rate of a single cavity photon via a single cavity phonon, calculated to be g/2pi = 292 kHz.

  14. Approximate Teleportation of an Unknown Atomic-Entangled State with Dissipative Atom-Cavity Resonant Jaynes-Cummings Model

    Institute of Scientific and Technical Information of China (English)

    LIU Zong-Liang; LI Shao-Hua; CHEN Chang-Yong

    2008-01-01

    We propose a scheme for approximately and conditionally teleporting an unknown atomic-entangled state in dissipative cavity QED.It is the further development of the scheme of [Phys.Rev.A 69 (2004) 064302],where the cavity mode decay has not been considered and the state teleportated is an unknown atomic state.In this paper,we investigate the influence of the decay on the approximate and conditional teleportation of the unknown atomic-entangled state,which is different from that teleportated in [Phys.Rev.A 69 (2004) 064302] and then give the fidelity of the teleportation,which depends on the cavity mode decay.The scheme may be generalized to not only the teleportation of the cavity-mode-entangled-state by means of a single atom but also the teleportation of the unknown trapped-ion-entangled-state in a linear ion trap.

  15. A Design of Constant Temperature Heating Circuit for a Resonant Cavity%一种谐振腔体的恒温加热电路设计

    Institute of Scientific and Technical Information of China (English)

    钦华

    2015-01-01

    For resonant cavity method is used to analyze cigarette density and humidity detection process,the stability of the resonant frequency accuracy of the test is very important.In this paper,a design scheme of con-stant temperature heating circuit for a resonant cavity in microwave density and humidity detector is presented, first introduces the measuring principle and architecture of the circuit,and then introduces the design and im-plementation,final y,experiments show that the design can meet the microwave detector testing requirements for measuring accuracy and stability.%对于利用谐振腔法对烟支进行湿密度检测过程中,谐振频率的稳定对测试精度至关重要。该文提出了一种微波密度湿度检测仪中谐振腔体恒温加热电路的设计方案,先介绍了该电路构成和原理,然后介绍了电路设计与实现,最后通过实验表明该电路可以满足微波密度湿度检测仪对测量精度和稳定性的要求。

  16. Radiation Characterization Summary: ACRR Central Cavity Free-Field Environment with the 32-Inch Pedestal at the Core Centerline (ACRR-FF-CC-32-cl).

    Energy Technology Data Exchange (ETDEWEB)

    Vega, Richard Manuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Parma, Edward J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Naranjo, Gerald E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lippert, Lance L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vehar, David W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Griffin, Patrick J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    This document presents the facilit y - recommended characteri zation o f the neutron, prompt gamma - ray, and delayed gamma - ray radiation fields in the Annular Core Research Reactor ( ACRR ) for the cen tral cavity free - field environment with the 32 - inch pedestal at the core centerline. The designation for this environmen t is ACRR - FF - CC - 32 - cl. The neutron, prompt gamma - ray , and delayed gamma - ray energy spectra , uncertainties, and covariance matrices are presented as well as radial and axial neutron and gamma - ray fluence profiles within the experiment area of the cavity . Recommended constants are given to facilitate the conversion of various dosimetry readings into radiation metrics desired by experimenters. Representative pulse operations are presented with conversion examples . Acknowledgements The authors wish to th ank the Annular Core Research Reactor staff and the Radiation Metrology Laboratory staff for their support of this work . Also thanks to David Ames for his assistance in running MCNP on the Sandia parallel machines.

  17. Experimental and theoretical study of red-shifted solitonic resonant radiation in photonic crystal fibers and generation of radiation seeded Raman solitons

    CERN Document Server

    Bose, Surajit; Chattopadhyay, Rik; Pal, Mrinmay; Bhadra, Shyamal K

    2015-01-01

    The red shifted solitonic resonant radiation is a fascinating phase matching phenomenon that occurs when an optical pulse, launched in the normal dispersion regime of photonic crystal fiber, radiates across the zero dispersion wavelength. The formation of such phase-matched radiation is independent of the generation of any optical soliton and mainly governed by the leading edge of input pump which forms a shock front. The radiation is generated at the anomalous dispersion regime and found to be confined both in time and frequency domain. We experimentally investigate the formation of such radiations in photonic crystal fibers with detailed theoretical analysis. Our theoretical predictions corroborate well with experimental results. Further we extend our study for long length fiber and investigate the interplay between red-shifted solitonic resonant radiation and intrapulse Raman scattering (IPRS). It is observed that series of radiation-seeded Raman solitons are generated in anomalous dispersion regime.

  18. Magnetic resonance diffusion tensor imaging-based evaluation of optic-radiation shape and position in meningioma.

    Science.gov (United States)

    Lv, Xueming; Chen, Xiaolei; Xu, Bainan; Zhang, Jiashu; Zheng, Gang; Li, Jinjiang; Li, Fangye; Sun, Guochen

    2012-03-25

    Employing magnetic resonance diffusion tensor imaging, three-dimensional white-matter imaging and conventional magnetic resonance imaging can demonstrate the tumor parenchyma, peritumoral edema and compression on surrounding brain tissue. A color-coded tensor map and three-dimensional tracer diagram were applied to clearly display the optic-radiation location, course and damage. Results showed that the altered anisotropy values of meningioma patients corresponded with optic-radiation shape, size and position on both sides. Experimental findings indicate that the magnetic resonance diffusion tensor imaging technique is a means of tracing and clearly visualizing the optic radiation.

  19. Magnetic resonance diffusion tensor imaging-based evaluation of optic-radiation shape and position in meningioma

    Institute of Scientific and Technical Information of China (English)

    Xueming Lv; Xiaolei Chen; Bainan Xu; Gang Zheng; Jinjiang Li; Fangye Li; Guochen Sun; liusan

    2012-01-01

    Employing magnetic resonance diffusion tensor imaging, three-dimensional white-matter imaging and conventional magnetic resonance imaging can demonstrate the tumor parenchyma, peritumoral edema and compression on surrounding brain tissue. A color-coded tensor map and three-dimensional tracer diagram were applied to clearly display the optic-radiation location, course and damage. Results showed that the altered anisotropy values of meningioma patients corresponded with optic-radiation shape, size and position on both sides. Experimental findings indicate that the magnetic resonance diffusion tensor imaging technique is a means of tracing and clearly visualizing the optic radiation.

  20. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a (60)Co Magnetic Resonance Image Guidance Radiation Therapy System

    DEFF Research Database (Denmark)

    Wooten, H Omar; Green, Olga; Yang, Min

    2015-01-01

    % prescription reference isodoses, respectively, and heterogeneity was on average 4% greater. Comparisons of OAR mean dose showed generally better sparing with linac plans in the low-dose range doses >20 Gy. The mean doses for all (60)Co plan OARs were within......PURPOSE: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating (60)Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. METHODS AND MATERIALS...... plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The (60)Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses...

  1. Few-cycle fiber pulse compression and evolution of negative resonant radiation

    CERN Document Server

    McLenaghan, Joanna

    2013-01-01

    We present numerical simulations and experimental observations of the spectral expansion of fs-pulses compressing in optical fibers. Using the input pulse frequency chirp we are able to scan through the pulse compression spectra and observe in detail the emergence of negative-frequency resonant radiation (NRR), a recently discovered pulse instability coupling to negative frequencies [Rubino et al., PRL 108, 253901 (2012)]. We observe how the compressing pulse is exciting NRR as long as it overlaps spectrally with the resonant frequency. Furthermore, we observe that optimal pulse compression can be achieved at an optimal input chirp and for an optimal fiber length. The results are important for Kerr-effect pulse compressors, to generate novel light sources, as well as for the observation of quantum vacuum radiation.

  2. Radiation-Induced Liver Damage: Correlation of Histopathology with Hepatobiliary Magnetic Resonance Imaging, a Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Seidensticker, Max, E-mail: max.seidensticker@med.ovgu.de [Universitätsklinik Magdeburg, Klinik für Radiologie und Nuklearmedizin (Germany); Burak, Miroslaw [Pomeranian Medical University, Department of Diagnostic Imaging and Interventional Radiology (Poland); Kalinski, Thomas [Universitätsklinik Magdeburg, Institut für Pathologie (Germany); Garlipp, Benjamin [Universitätsklinik Magdeburg, Klinik für Allgemein-, Viszeral- und Gefäßchirurgie (Germany); Koelble, Konrad [Philipps Universität Marburg, Fachbereich Medizin der, Abteilung für Neuropathologie (Germany); Wust, Peter [Charité Universitätsmedizin Berlin, Klinik für Radioonkologie und Strahlentherapie (Germany); Antweiler, Kai [Universitätsklinik Magdeburg, Institut für Biometrie und Medizinische Informatik (Germany); Seidensticker, Ricarda; Mohnike, Konrad; Pech, Maciej; Ricke, Jens [Universitätsklinik Magdeburg, Klinik für Radiologie und Nuklearmedizin (Germany)

    2015-02-15

    PurposeRadiotherapy of liver malignancies shows promising results (radioembolization, stereotactic irradiation, interstitial brachytherapy). Regardless of the route of application, a certain amount of nontumorous liver parenchyma will be collaterally damaged by radiation. The functional reserve may be significantly reduced with an impact on further treatment planning. Monitoring of radiation-induced liver damage by imaging is neither established nor validated. We performed an analysis to correlate the histopathological presence of radiation-induced liver damage with functional magnetic resonance imaging (MRI) utilizing hepatobiliary contrast media (Gd-BOPTA).MethodsPatients undergoing local high-dose-rate brachytherapy for whom a follow-up hepatobiliary MRI within 120 days after radiotherapy as well as an evaluable liver biopsy from radiation-exposed liver tissue within 7 days before MRI were retrospectively identified. Planning computed tomography (CT)/dosimetry was merged to the CT-documentation of the liver biopsy and to the MRI. Presence/absence of radiation-induced liver damage (histopathology) and Gd-BOPTA uptake (MRI) as well as the dose applied during brachytherapy at the site of tissue sampling was determined.ResultsFourteen biopsies from eight patients were evaluated. In all cases with histopathological evidence of radiation-induced liver damage (n = 11), no uptake of Gd-BOPTA was seen. In the remaining three, cases no radiation-induced liver damage but Gd-BOPTA uptake was seen. Presence of radiation-induced liver damage and absence of Gd-BOPTA uptake was correlated with a former high-dose exposition.ConclusionsAbsence of hepatobiliary MRI contrast media uptake in radiation-exposed liver parenchyma may indicate radiation-induced liver damage. Confirmatory studies are warranted.

  3. Acoustofluidics: theory and simulation of radiation forces at ultrasound resonances in microfluidic devices

    DEFF Research Database (Denmark)

    Barnkob, Rune; Bruus, Henrik

    2009-01-01

    Theoretical analysis is combined with numerical simulations to optimize designs and functionalities of acoustofluidic devices, i.e. microfluidic devices in which ultrasound waves are used to anipulate biological particles. The resonance frequencies and corresponding modes of the acoustic fields...... the largest possible acoustic powers are obtained in the microfluidic system, the time-averaged acoustic radiation force on single particles is determined. Schemes for in situ calibration of this force are presented and discussed....

  4. Effects of radiation damping on photorecombination of C4 + ions for the KLL resonance

    Science.gov (United States)

    Li, Chuan-Ying; Wu, Yong; Qu, Yi-Zhi; Wang, Jian-Guo

    2016-10-01

    A numerical method based on Zabaydullin and Dubau's work [O. Zabaydullin and J. Dubau, J. Phys. B: At. Mol. Opt. Phys. 45, 115002 (2012), 10.1088/0953-4075/45/11/115002] has been developed to calculate the Cauchy principal value integral in scattering matrices and obtain photorecombination (PR) cross sections of low-lying resonances according to Davies and Seaton's theory [J. Phys. B 2, 757 (1969), 10.1088/0022-3700/2/7/304], in which radiation damping is included. The Dirac R -matrix method is employed to secure the dipole matrix. Using this method, PR cross sections of C4 + for the KLL resonance are acquired, and compared with available experimental measurements and other close-coupling theoretical results. It is shown that our damped cross sections reproduce the experimental data and are in agreement with other theoretical results. Meanwhile, radiation damping can reduce the PR cross section for the 1 s 2 p22P resonance (corresponding to two levels [(1s2p1 /2) 12 p3 /2] 1 /2 and [1s (2p3/22)2] 3 /2 by three orders of magnitude. The unresolved and underestimated resonances 1 s 2 p24P , 1 s 2 s 2 p 4P , and 1 s 2 p22P in the undamped Breit-Pauli R -matrix calculations [H. L. Zhang et al., J. Phys. B: At. Mol. Opt. Phys. 32, 1459 (1999), 10.1088/0953-4075/32/6/010] are corrected. Besides, dielectronic recombination cross sections of C4 + for the KLL resonance are also presented for comparison using the relativistic configuration-interaction (RCI) method implemented in flexible atomic code (fac), which show radiation damping has pronounced influences on 1 s 2 p22P due to much larger radiative rates compared with autoionization rates. Furthermore, radiative and autoionization rates for the intermediate states [(1s2p1 /2) 12 p3 /2] 1 /2 and [1s (2p3/22)2] 3 /2 of the He-like ions with 6 ≤Z ≤83 are calculated using fac, scaling laws of which are checked. Autoionization rates comply with the Zeff0 scaling law for Z ≥32 , which is caused by relativistic effects.

  5. 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)

  6. Radiation-Suppressed plasmonic open resonators designed by nonmagnetic transformation optics

    Science.gov (United States)

    Xu, Hongyi; Wang, Xingjue; Yu, Tianyuan; Sun, Handong; Zhang, Baile

    2012-01-01

    How to confine light energy associated with surface plasmon polaritons (SPPs) in a physical space with minimal radiation loss whereas creating maximum interacting section with surrounding environment is of particular interest in plasmonic optics. By virtue of transformation optics, we propose a design method of forming a polygonal surface-plasmonic resonator in fully open structures by applying the nonmagnetic affine transformation optics strategy. The radiation loss can be suppressed because SPPs that propagate in the designed open structures will be deceived as if they were propagating on a flat metal/dielectric interface without radiation. Because of the nonmagnetic nature of the transformation strategy, this design can be implemented with dielectric materials available in nature. An experimentally verifiable model is subsequently proposed for future experimental demonstration. Our design may find potential applications in omnidirectional sensing, light harvesting, energy storage and plasmonic lasing. PMID:23136641

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

    CERN Document Server

    Romanenko, A

    2014-01-01

    In a recent publication [Appl. Phys. Lett. 104, 092601 (2014)] Ciovati et al. claim that: 1) thermal effects were disregarded in our original work [*]; 2) increase of $Q$ at $T=2$ K up to about $B\\sim$100 mT in nitrogen doped cavities is just an extended low field $Q$ slope observed in non-doped cavities, which is furthermore attributed to the decrease of the "BCS" component of surface resistance. Here we show that both claims are wrong and the conclusions of Ciovati et al. are incorrect. [*] A. Romanenko and A. Grassellino, Appl. Phys. Lett. 102, 252603 (2013)

  8. Negative differential resistance in Josephson junctions coupled to a cavity

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Filatrella, G.; Pierro, V.

    2014-01-01

    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......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...

  9. Near-field thermal radiative emission of materials demonstrating near infrared surface polariton resonance

    Science.gov (United States)

    Petersen, Spencer Justin

    Surface polariton mediated near-field radiative transfer exceeds the blackbody limit by orders of magnitude and is quasimonochromatic. Thermophotovoltaic (TPV) power generation consists of converting thermal radiation into useful electrical energy and exhibits a peak performance near the TPV cell bandgap, which is typically located within the near infrared bandwidth. Therefore, an ideal emission source for a nanoscale gap TPV device, in which the emitter and cell are separated by no more than one peak emitted wavelength, will sustain surface polariton resonance at or near the TPV cell bandgap in the near infrared. To date, few materials have been identified that satisfy this requirement. The first objective of this dissertation is to theoretically explore dielectric Mie resonance-based (DMRB) electromagnetic metamaterials for the potential to sustain near infrared surface polariton resonance. Electromagnetic metamaterials are composite media, consisting of subwavelength, repeating unit structures called "meta-atoms." The microscopic configuration of the meta-atom can be engineered, dictating the effective macroscale electromagnetic properties of the bulk metamaterial, including the surface polariton resonance wavelength. DMRB metamaterials consist of dielectric nanoparticles within a host medium and are analyzed using an effective medium theory. The local density of electromagnetic states, an indicator of possibly harvestable energy near an emitting surface, is calculated for two DMRB metamaterials: spherical nanoparticles of 1) silicon carbide, and 2) silicon embedded in a host medium. Results show that the surface polariton resonance of these metamaterials is tunable and, for the silicon metamaterial only, is found in the near infrared bandwidth, making it a viable candidate for use in a nano-TPV device. In order to demonstrate the practicality thereof, the second objective is to fabricate and characterize DMRB metamaterials. Specimens are fabricated by hand

  10. Coherently Opening a High-Q Cavity

    Science.gov (United States)

    Tufarelli, Tommaso; Ferraro, Alessandro; Serafini, Alessio; Bose, Sougato; Kim, M. S.

    2014-04-01

    We propose a general framework to effectively "open" a high-Q resonator, that is, to release the quantum state initially prepared in it in the form of a traveling electromagnetic wave. This is achieved by employing a mediating mode that scatters coherently the radiation from the resonator into a one-dimensional continuum of modes such as a waveguide. The same mechanism may be used to "feed" a desired quantum field to an initially empty cavity. Switching between an open and "closed" resonator may then be obtained by controlling either the detuning of the scatterer or the amount of time it spends in the resonator. First, we introduce the model in its general form, identifying (i) the traveling mode that optimally retains the full quantum information of the resonator field and (ii) a suitable figure of merit that we study analytically in terms of the system parameters. Then, we discuss two feasible implementations based on ensembles of two-level atoms interacting with cavity fields. In addition, we discuss how to integrate traditional cavity QED in our proposal using three-level atoms.

  11. Cavity spin optodynamics

    CERN Document Server

    Brahms, N

    2010-01-01

    The dynamics of a large quantum spin coupled parametrically to an optical resonator is treated in analogy with the motion of a cantilever in cavity optomechanics. New spin optodynamic phenonmena are predicted, such as cavity-spin bistability, optodynamic spin-precession frequency shifts, coherent amplification and damping of spin, and the spin optodynamic squeezing of light.

  12. Low-dissipation cavity optomechanics in single-crystal diamond

    CERN Document Server

    Mitchell, Matthew; Lake, David P; Barclay, Paul E

    2015-01-01

    Single-crystal diamond cavity optomechanical devices are a promising example of a hybrid quantum system: by coupling mechanical resonances to both light and electron spins, they can enable new ways for photons to control solid state qubits. However, creating devices from high quality bulk diamond chips is challenging. Here we demonstrate single-crystal diamond cavity optomechanical devices that can enable photon-phonon-spin coupling. Cavity optomechanical coupling to $2\\,\\text{GHz}$ frequency ($f_\\text{m}$) mechanical resonances is observed. In room temperature ambient conditions, the resonances have a record combination of low dissipation ($Q_\\text{m} > 9000$) and high frequency, with $Q_\\text{m}\\cdot f_\\text{m} \\sim 1.9\\times10^{13}$ sufficient for room temperature single phonon coherence. The system is nearly sideband resolved, and radiation pressure is used to excite $\\sim 31\\,\\text{pm}$ amplitude mechanical self-oscillations that can drive diamond color centre electron spin transitions.

  13. Maintenance of the resonance in a cavity filled with a variable density plasma; Entretien de la resonance d'une cavite chargee par un plasma de densite variable

    Energy Technology Data Exchange (ETDEWEB)

    Melin, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    A study has been made of the possibility of keeping in resonance a cavity filled with a plasma of variable density; only the low HF power zone has been examined (less than a few dozen W). A calculation is first made, for the chosen experimental conditions, of the slipping of the resonance frequency of a cavity as a function of the plasma parameters (density, temperature), with a view to obtaining an idea of its importance. A description is then given of the experimental set-up: the S band cavity (3000 Mc/sec) is supplied by a carcinotron type generator; use is made of the plasma of a positive column whose density ({approx}10{sup 11} cm{sup -3}) can easily be controlled so as to obtain slipping of the cavity frequency ({delta}F{sub max} {approx} 50 Mc/s). The zone of automatic agreement thus obtained for the S band is 3 per cent continuously ({approx}100 Mc/s) and 1 per cent ({approx}30 Mc/s) with a response time of 10 {mu}s (sudden changes in density, {delta}n {approx} 5.10{sup 10} cm{sup 3}). These characteristics already compare very favorably with existing systems, and can easily be improved. (author) [French] On etudie une possibilite de maintenir a la resonance une cavite chargee par un plasma dont la densite varie; on se limite au domaine des puissances HF faibles (< quelques dizaines de W). On calcule tout d'abord, pour les conditions experimentales choisies, le glissement de la frequence de resonance d'une cavite en fonction des parametres du plasma, densite, temperature, pour en evaluer les ordres de grandeur. On decrit ensuite la realisation experimentale: la cavite bande S (3000 Mc/s) est alimentee par un generateur du type carcinotron; on utilise le plasma d'une colonne positive, dont on controle facilement la densite ({approx}10{sup 11} cm{sup -3}) pour faire glisser en frequence la cavite ({delta}F{sub max} {approx} 50 Mc/s). La zone d'accord automatique obtenue ainsi pour la bande S est de 3 pour cent en continu ({approx}100 Mc

  14. Analysis and suppression of RF radiation from the PSI 590 MeV cyclotron Flat Top Cavity

    Science.gov (United States)

    Pogue, N. J.; Stingelin, L.; Adelmann, A.

    2016-08-01

    The Flat Top Cavity, located in the PSI HIPA Ring Cyclotron leaks RF power of several kilo Watts into the cyclotron's vacuum space causing several complications. A detailed electromagnetic model was created and simulations performed to analyze the mechanisms by which power is leaking out of the Flat Top Cavity. The tolerances needed to limit the leaked power in future iterations of the Flat Top cavity are reported. Comparison of the model to measurements are described as well as two potential methods to limit power leakage. These studies will have direct impact on future RF cavity designs for cyclotrons as power levels increase and higher RF fields are required.

  15. Analysis and Suppression of RF Radiation from the PSI 590MeV Cyclotron Flat Top Cavity

    CERN Document Server

    Pogue, Nathaniel; Stingelin, Lukas

    2016-01-01

    The Flat Top Cavity, located in the PSI HIPA Ring Cyclotron leaks RF power of several kilo Watts into the cyclotrons vacuum space causing several complications. A detailed electromagnetic model was created and simulations performed to analyze the mechanisms by which power is leaking out of the Flat Top Cavity. The tolerances needed to limit the leaked power in future iterations of the Flat Top cavity are reported. Comparison of the model to measurements are described as well as two potential methods to limit power leakage. These studies will have direct impact on future RF cavity designs for cyclotrons as power levels increase and higher RF fields are required.

  16. USE OF PROTON MAGNETIC RESONANCE SPECTROSCOPIC IMAGING DATA IN PLANNING FOCAL RADIATION THERAPIES FOR BRAIN TUMORS

    Directory of Open Access Journals (Sweden)

    Edward E Graves

    2011-05-01

    Full Text Available Advances in radiation therapy for malignant neoplasms have produced techniques such as Gamma Knife radiosurgery, capable of delivering an ablative dose to a specific, irregular volume of tissue. However, efficient use of these techniques requires the identification of a target volume that will produce the best therapeutic response while sparing surrounding normal brain tissue. Accomplishing this task using conventional computed tomography (CT and contrast-enhanced magnetic resonance imaging (MRI techniques has proven difficult because of the difficulties in identifying the effective tumor margin. Magnetic resonance spectroscopic imaging (MRSI has been shown to offer a clinically-feasible metabolic assessment of the presence and extent of neoplasm that can complement conventional anatomic imaging. This paper reviews current Gamma Knife protocols and MRSI acquisition, reconstruction, and interpretation techniques, and discusses the motivation for including magnetic resonance spectroscopy findings while planning focal radiation therapies. A treatment selection and planning strategy incorporating MRSI is then proposed, which can be used in the future to assess the efficacy of spectroscopy-based therapy planning.

  17. The influence of resonance radiation transport on the contraction of a glow discharge in argon

    Science.gov (United States)

    Golubovskii, Yu B.; Maiorov, V. A.

    2015-04-01

    The role of resonance radiation transport in the contraction of a positive column in an argon glow discharge is studied numerically. The theory is based on the self-consistent solution of the ambipolar diffusion equation for electrons, the diffusion equation for metastable atoms and the Biberman-Holstein equation for resonance atoms. To calculate the ionization and excitation rates, the Boltzmann equation is solved in a local approximation taking into account elastic, inelastic and electron-electron collisions. A solution method for a boundary problem is developed which allows one to obtain a hysteresis of the parameters during a continuous transition from a diffuse mode to a contracted mode through an unstable branch. At small currents there is a diffuse discharge where the role of radiation transport is inessential because the radial distributions of electrons and excited atoms are close to the fundamental modes of the corresponding equations. Under these conditions, the traditional approximation of ‘effective lifetime’ is accurate enough. For a contracted discharge, this approximation is not applicable because the higher diffusion and radiation modes play a notable role and a more strict description of radiation transport is required. It is shown that, when radiation transport is taken into account, the width of a filament in a contracted discharge significantly exceeds that obtained in the traditional ‘effective lifetime’ approximation. The critical current, when the discharge abruptly turns into a contracted mode, is shifted towards higher current values. The results obtained in this paper can also relate to a discharge in other inert gases.

  18. Study of the fluctuations of the partial and total radiative widths by neutron capture resonance method; Etude des fluctuations des largeurs radiatives partielles et totales par la capture des neutrons de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, V.D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-06-01

    Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths {gamma}{sub {gamma}} from resonance to resonance, variation of {gamma}{sub {gamma}} with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [French] Par la capture des neutrons de resonance dont les energies sont selectionnees a l'aide de la technique du temps de vol, differents types d'experiences ont ete realisees concernant les etudes des distributions des largeurs radiatives partielles, des effets de correlation entre differentes voies de desexcitation, de la fluctuation des largeurs radiatives totales {gamma}{sub {gamma}} de resonance a resonance, de la variation de la quantite {gamma}{sub {gamma}} en fonction du nombre de masse et de la mise en evidence de l'existence du processus de capture potentielle. Quelques autres applications de l'emploi du spectre de rayons gamma ont egalement ete presentees. (auteur)

  19. Cooperative emission from an ensemble of three-level Λ radiators in a cavity: An insight from the viewpoint of dynamics of nonlinear systems

    Science.gov (United States)

    Ryzhov, I. V.; Vasil'ev, N. A.; Kosova, I. S.; Shtager, M. D.; Malyshev, V. A.

    2017-05-01

    Cooperative radiation emitted by an ensemble of three-level optical systems with a doublet in the ground state (Λ scheme), which is placed into a cyclic cavity, is studied theoretically. In contrast to the two-level model of emitters, this process with such a configuration of operating transitions may occur without population inversion in the whole, if the doublet is prepared at the initial instant in a superposition (coherent) state. In the ideal case of a Hamilton system, in which the cavity losses and relaxation in the radiator ensemble are disregarded, the conservation laws are derived, which allow a substantial reduction of the dimension of the phase space of the model (ℝ11 → ℝ5) and the application of methods of dynamics of nonlinear systems for analyzing the three-level superradiance under these conditions. The possibility of different (both quasiperiodic and chaotic) scenarios of the three-level superradiance is demonstrated on the basis of Poincaré's mappings. Global bifurcation of the system upon a transition from the conventional superradiance regime to inversionless one is revealed. The effects of cavity losses, as well as homogeneous and inhomogeneous broadening in the system of radiators on the regularities found are also discussed.

  20. Efficient Radiation by Electrically Small Antennas made of Coupled Split-ring Resonators

    Science.gov (United States)

    Peng, Liang; Chen, Peiwei; Wu, Aiting; Wang, Gaofeng

    2016-09-01

    In this paper, coupled split-ring resonators (SRRs) are used to construct the electrically small antennas. We show that through strong magnetic coupling, the coupled SRRs composite can oscillate at a wavelength much larger than its total size. Due to its magnetic dipole feature, the coupled SRRs composite allows the electromagnetic (EM) power to radiate and hence forms the electrically small antenna (ESA). Because of the high-Q resonance, the ESA could be easily matched to the driving circuit in the microwave region, through mutual induction approach. We also demonstrate that the radiation efficiency of such ESAs can be drastically improved if the current distribution on individual SRRs is similar, which is achievable by carefully designing the ESAs. From our simulations and experimental measurements, the ESAs’ radiation efficiency can reach up to 41%, with relative footprint of 0.05λ0 × 0.05λ0. Our approach would be an effective way to realize ESAs with high efficiency, which can be implemented on chip through the standard planar lithography.

  1. Self-formed cavity quantum electrodynamics in coupled dipole cylindrical-waveguide systems.

    Science.gov (United States)

    Afshar V, S; Henderson, M R; Greentree, A D; Gibson, B C; Monro, T M

    2014-05-01

    An ideal optical cavity operates by confining light in all three dimensions. We show that a cylindrical waveguide can provide the longitudinal confinement required to form a two dimensional cavity, described here as a self-formed cavity, by locating a dipole, directed along the waveguide, on the interface of the waveguide. The cavity resonance modes lead to peaks in the radiation of the dipole-waveguide system that have no contribution due to the skew rays that exist in longitudinally invariant waveguides and reduce their Q-factor. Using a theoretical model, we evaluate the Q-factor and modal volume of the cavity formed by a dipole-cylindrical-waveguide system and show that such a cavity allows access to both the strong and weak coupling regimes of cavity quantum electrodynamics.

  2. Spontaneous creation and persistence of ground-state coherence in a resonantly driven intra-cavity atomic ensemble

    CERN Document Server

    Norris, D G; Orozco, L A; Barberis-Blostein, P; Carmichael, H J; 10.1103/PhysRevA.86.053816

    2012-01-01

    The spontaneous creation and persistence of ground-state coherence in an ensemble of intracavity Rb atoms has been observed as a quantum beat. Our system realizes a quantum eraser, where the detection of a first photon prepares a superposition of ground-state Zeeman sublevels, while detection of a second erases the stored information. Beats appear in the time-delayed photon-photon coincidence rate (intensity correlation function). We study the beats theoretically and experimentally as a function of system parameters, and find them remarkably robust against perturbations such as spontaneous emission. Although beats arise most simply through single-atom-mediated quantum interference, scattering pathways involving pairs of atoms interfere also in our intracavity experiment. We present a detailed model which identifies all sources of interference and accounts for experimental realities such as imperfect pre-pumping of the atomic beam, cavity birefringence, and the transit of atoms across the cavity mode.

  3. Travelling-wave resonant four-wave mixing breaks the limits of cavity-enhanced all-optical wavelength conversion

    Science.gov (United States)

    Morichetti, Francesco; Canciamilla, Antonio; Ferrari, Carlo; Samarelli, Antonio; Sorel, Marc; Melloni, Andrea

    2011-01-01

    Wave mixing inside optical resonators, while experiencing a large enhancement of the nonlinear interaction efficiency, suffers from strong bandwidth constraints, preventing its practical exploitation for processing broad-band signals. Here we show that such limits are overcome by the new concept of travelling-wave resonant four-wave mixing (FWM). This approach combines the efficiency enhancement provided by resonant propagation with a wide-band conversion process. Compared with conventional FWM in bare waveguides, it exhibits higher robustness against chromatic dispersion and propagation loss, while preserving transparency to modulation formats. Travelling-wave resonant FWM has been demonstrated in silicon-coupled ring resonators and was exploited to realize a 630-μm-long wavelength converter operating over a wavelength range wider than 60 nm and with 28-dB gain with respect to a bare waveguide of the same physical length. Full compatibility of the travelling-wave resonant FWM with optical signal processing applications has been demonstrated through signal retiming and reshaping at 10 Gb s−1 PMID:21540838

  4. Applications of cavity optomechanics

    Science.gov (United States)

    Metcalfe, Michael

    2014-09-01

    "Cavity-optomechanics" aims to study the quantum properties of mechanical systems. A common strategy implemented in order to achieve this goal couples a high finesse photonic cavity to a high quality factor mechanical resonator. Then, using feedback forces such as radiation pressure, one can cool the mechanical mode of interest into the quantum ground state and create non-classical states of mechanical motion. On the path towards achieving these goals, many near-term applications of this field have emerged. After briefly introducing optomechanical systems and describing the current state-of-the-art experimental results, this article summarizes some of the more exciting practical applications such as ultra-sensitive, high bandwidth accelerometers and force sensors, low phase noise x-band integrated microwave oscillators and optical signal processing such as optical delay-lines, wavelength converters, and tunable optical filters. In this rapidly evolving field, new applications are emerging at a fast pace, but this article concentrates on the aforementioned lab-based applications as these are the most promising avenues for near-term real-world applications. New basic science applications are also becoming apparent such as the generation of squeezed light, testing gravitational theories and for providing a link between disparate quantum systems.

  5. Applications of cavity optomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Metcalfe, Michael [Booz Allen Hamilton, 3811 Fairfax Drive, Arlington, Virginia 22203 (United States)

    2014-09-15

    Cavity-optomechanics” aims to study the quantum properties of mechanical systems. A common strategy implemented in order to achieve this goal couples a high finesse photonic cavity to a high quality factor mechanical resonator. Then, using feedback forces such as radiation pressure, one can cool the mechanical mode of interest into the quantum ground state and create non-classical states of mechanical motion. On the path towards achieving these goals, many near-term applications of this field have emerged. After briefly introducing optomechanical systems and describing the current state-of-the-art experimental results, this article summarizes some of the more exciting practical applications such as ultra-sensitive, high bandwidth accelerometers and force sensors, low phase noise x-band integrated microwave oscillators and optical signal processing such as optical delay-lines, wavelength converters, and tunable optical filters. In this rapidly evolving field, new applications are emerging at a fast pace, but this article concentrates on the aforementioned lab-based applications as these are the most promising avenues for near-term real-world applications. New basic science applications are also becoming apparent such as the generation of squeezed light, testing gravitational theories and for providing a link between disparate quantum systems.

  6. 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

  7. A selective pyroelectric detector of millimeter-wave radiation with an ultrathin resonant meta-absorber

    Science.gov (United States)

    Paulish, A. G.; Kuznetsov, S. A.

    2016-11-01

    The results of experimental investigations of spectral and amplitude-frequency characteristics for a discrete wavelength-selective pyroelectric detector operating in the millimetric band are presented. The high spectral selectivity is attained due to integrating the detector with a resonant meta-absorber designed for a close-to-unity absorptivity at 140 GHz. It is demonstrated that the use of this meta-absorber provides an opportunity to construct small-sized and inexpensive multispectral polarization-sensitive systems for radiation detection in the range of millimeter and submillimeter waves.

  8. Fractional Boltzmann equation for multiple scattering of resonance radiation in low-temperature plasma

    Energy Technology Data Exchange (ETDEWEB)

    Uchaikin, V V; Sibatov, R T, E-mail: vuchaikin@gmail.com, E-mail: ren_sib@bk.ru [Ulyanovsk State University, 432000, 42 Leo Tolstoy str., Ulyanovsk (Russian Federation)

    2011-04-08

    The fractional Boltzmann equation for resonance radiation transport in plasma is proposed. We start with the standard Boltzmann equation; averaging over photon frequencies leads to the appearance of a fractional derivative. This fact is in accordance with the conception of latent variables leading to hereditary and non-local dynamics (in particular, fractional dynamics). The presence of a fractional material derivative in the equation is concordant with heavy tailed distribution of photon path lengths and with spatiotemporal coupling peculiar to the process. We discuss some methods of solving the obtained equation and demonstrate numerical results in some simple cases.

  9. Quantum Theory of \\v{C}erenkov Radiation, Spectral Cutoff and Resonances

    CERN Document Server

    Kaminer, Ido; Harari, Gal; Sheinfux, Hanan Herzig; Levy, Amir; Skirlo, Scott; Nemirovsky, Jonathan; Joannopoulos, John D; Segev, Mordechai; Soljačić, Marin

    2016-01-01

    We show that the well-established \\v{C}erenkov Effect contains new phenomena arising directly from the quantum nature of the charged particles. These include large deviations from the classically-expected radiation intensity and angle. Most importantly, we find that the traditional Cerenkov angle splits, confining the emitted radiation into two distinctive cones into which two photonic shock waves are emitted. Interestingly, one of the two shockwaves can move on a backward cone, which is otherwise considered impossible for \\v{C}erenkov Radiaiton in ordinary materials. Moreover, for specific values of the particle momentum, we predict an upper frequency cutoff in the photon emission. Surprisingly, for this extremum frequency we find a diverging rate of photon emission, implying this is a new resonant light-matter interaction. Some of these new effects cannot be found without the full quantum derivation. Importantly, our findings are observable for electron beams with realistic parameters, offering new applicat...

  10. Photonic superdiffusive motion in resonance line radiation trapping - partial frequency redistribution effects

    CERN Document Server

    Alves-Pereira, A R; Martinho, J M G; Berberan-Santos, M N

    2007-01-01

    The relation between the jump length probability distribution function and the spectral line profile in resonance atomic radiation trapping is considered for Partial Frequency Redistribution (PFR) between absorbed and reemitted radiation. The single line Opacity Distribution Function [M.N. Berberan-Santos et.al. J.Chem.Phys. 125, 174308 (2006)] is generalized for PFR and used to discuss several possible redistribution mechanisms (pure Doppler broadening, combined natural and Doppler broadening and combined Doppler, natural and collisional broadening). It is shown that there are two coexisting scales with a different behavior: the small scale is controlled by the intricate PFR details while the large scale is essentially given by the atom rest frame redistribution asymptotic. The pure Doppler and combined natural, Doppler and collisional broadening are characterized by both small and large scale superdiffusive Levy flight behaviors while the combined natural and Doppler case has an anomalous small scale behavi...

  11. Formation of silicon monoxide by radiative association: the impact of resonances

    CERN Document Server

    Forrey, Robert C; Stancil, Phillip C; McLaughlin, Brendan M

    2016-01-01

    Detailed quantum chemistry calculations within the multireference configuration interaction approximation with the Davidson correction (MRCI+Q) are presented using an aug-cc-pV6Z basis set, for the potential energy curves and transition dipole moments between low lying molecular states of singlet spin symmetry for the SiO molecule. The high quality molecular data are used to obtain radiative association cross sections and rate coefficients for collisions between ground state Si and O atoms. Quantal calculations are compared with semiclassical results. Using a quantum kinetic theory of radiative association in which quasibound levels are assumed to be in local thermodynamic equilibrium, we find that resonances play an important role in enhancing the rate coefficients at low temperatures by several orders of magnitude from that predicted by standard quantum scattering formulations. These new molecular formation rates may have important implications for applications in astrophysics.

  12. Formation of silicon monoxide by radiative association: the impact of resonances

    Science.gov (United States)

    Forrey, Robert C.; Babb, James F.; Stancil, Phillip C.; McLaughlin, Brendan M.

    2016-09-01

    Detailed quantum chemistry calculations within the multireference configuration interaction approximation with the Davidson correction are presented using an aug-cc-pV6Z basis set, for the potential energy curves and transition dipole moments between low lying molecular states of singlet spin symmetry for the SiO molecule. The high quality molecular data are used to obtain radiative association cross sections and rate coefficients for collisions between ground state Si and O atoms. Quantal calculations are compared with semiclassical results. Using a quantum kinetic theory of radiative association in which quasibound levels are assumed to be in local thermodynamic equilibrium, we find that resonances play an important role in enhancing the rate coefficients at low temperatures by several orders of magnitude from that predicted by standard quantum scattering formulations. These new molecular formation rates may have important implications for applications in astrophysics.

  13. Gain and Efficiency of a Superconducting Microwave Compressor with a Switching Cavity in an Interference Switch

    Science.gov (United States)

    Artemenko, S. N.; Samoylenko, G. M.

    2016-11-01

    We study the processes of radiation output from a microwave storage cavity through a superconducting interference switch, which is based on a H-junction with a superconducting switching cavity connected to the side branch of the junction for various ways of controlling the parameters of the switching cavity. It is shown that efficient control over radiation output in such a switch can be achieved by varying the resonance frequency or Q-factor of the switching cavity, as well as by varying these parameters simultaneously. It is found that in the case of controlling the resonance frequency of the switching cavity, there exists an optimal interval of the frequency variation, within which the total efficiency and extraction efficiency are maximum. When the Q-factor of the switching cavity changes, the dependence of the total efficiency and extraction efficiency on the Q-factor has the monotonic character. The mixed regime of radiation output control is also studied. The envelopes of the output compressor pulses are plotted on the basis of recurrent relationships between the amplitudes of the waves in the system for three regimes of switch operation. It is shown that pulses with an almost rectangular shape of the envelope can be formed in the regime of controlling the switching cavity by varying the Q-factor. An example of possible realization of the switching cavity is considered.

  14. Efficacy of cobalt-60 radiation therapy for the treatment of nasal cavity nonkeratinizing squamous cell carcinoma in the dog.

    Science.gov (United States)

    Correa, Stephanie Shank; Mauldin, G Neal; Mauldin, Glenna E; Patnaik, Amiya K

    2003-01-01

    The purposes of this study were to evaluate the efficacy of cobalt-60 radiotherapy in the treatment of nonkeratinizing squamous cell carcinoma of the nasal cavity in dogs and to compare this treatment group to historical controls. Six dogs with histopathologically confirmed nasal cavity nonkeratinizing squamous cell carcinoma were treated with cobalt-60 radiotherapy to a total dose of either 63 Gy or 54 Gy. Overall survival times ranged from 30 days to 330 days, with a median survival time of 165 days. Nasal cavity nonkeratinizing squamous cell carcinoma in the dog is an aggressive tumor that responds poorly to radiotherapy.

  15. Effect of External Radiation Filed on the Properties of the Atoms and Cavity Field in the Tavis-Cummings Model

    Institute of Scientific and Technical Information of China (English)

    王忠纯

    2004-01-01

    @@ We study the properties of the atoms and cavity field in the Tavis-Cummings Model where the two atoms interact each other and also are driven by an external classical field.We consider the special case that the cavity is initially in a coherent state.After work out the atomic inversion, the average photons number and the Mandel parameter in the driven Tavis-Cummings Model, we do numerical analysis of them, and pay special attention to the dynamical behavior of the atoms and the cavity field modified by the external field.

  16. RESONANCE CONTROL FOR THE COUPLED CAVITY LINAC AND DRIFT TUBE LINAC STRUCTURES OF THE SPALLATION NEUTRON SOURCE LINAC USING A CLOSED-LOOP WATER COOLING SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Bernardin, J. D. (John D.); Brown, R. L. (Richard L.); Brown, S. K. (Stanley K.); Bustos, G. R. (Gerald R.); Crow, M.L. (Martin L.); Gregory, W. S.; Hood, M. E. (Michael E.); Jurney, J. D. (James D.); Medalen, I. (Ivan); Owen, A. C. (Albert C.); Weiss, Robert E.

    2001-01-01

    The Spallation Neutron Source (SNS) is a facility being designed for scientific and industrial research and development. SNS will generate and use neutrons as a diagnostic tool for medical purposes, material science, etc. The neutrons will be produced by bombarding a heavy metal target with a high-energy beam of protons, generated and accelerated with a linear particle accelerator, or linac. The low energy end of the linac consists of two room temperature copper structures, the drift tube linac (DTL), and the coupled cavity linac (CCL). Both of these accelerating structures use large amounts of electrical energy to accelerate the protons to an energy of 185 MeV. Approximately 60-80% of the electrical energy is dissipated in the copper structure and must be removed. This is done using specifically designed water cooling passages within the linac's copper structure. Cooling water is supplied to these cooling passages by specially designed resonance control and water cooling systems.

  17. 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...

  18. A resonance shift prediction based on the Boltzmann-Ehrenfest principle for cylindrical cavities with a rigid sphere

    DEFF Research Database (Denmark)

    Orozco Santillan, Arturo; Cutanda Henríquez, Vicente

    2008-01-01

    devices. It is shown that the use of the Boltzmann-Ehrenfest principle of adiabatic invariance allows the derivation of an expression for the resonance frequency shift in a simpler and more direct way than a method based on a Green’s function reported in the literature. The position of the sphere can...

  19. Distribution of total radiation widths for neutron resonances of Pt isotopes

    Directory of Open Access Journals (Sweden)

    Koehler P.E.

    2015-01-01

    Full Text Available High quality neutron capture and transmission data were measured on isotopically enriched 192,194,195,196Pt and natural Pt samples at ORELA. R-matrix analysis of this data revealed resonance parameters for 159, 413, 423, 258, and 11 neutron resonances for neutron energies below 5.0, 16.0, 7.5, 16.0, and 5.0 keV for 192,194,195,196,198Pt+n, respectively. Earlier analysis of data on reduced neutron widths, Γ0n, showed that the distributions of Γ0n for 192,194Pt deviate significantly from the Porter-Thomas distribution (PTD predicted by random matrix theory. In this contribution we report on preliminary results of the analysis of distribution of total radiation widths, Γγ, in 192,194,195,196Pt+n reactions. Comparison of experimental data with predictions made within the nuclear statistical model indicates that standard models of Photon Strength Functions (PSFs and Nuclear Level Density predict Γγ distributions which are too narrow. We found that satisfactory agreement between experimental and simulated distributions can be obtained only by a strong suppression of the PSFs at low γ-ray energies and/or by violation of the usual assumption that primary transitions from neutron resonances follow the PTD. The shape of PSFs needed for reproduction of our Γγ data also nicely reproduces spectra from several (n,γ experiments on the neighbor nuclide 198Au.

  20. 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

  1. A longitudinal magnetic resonance elastography study of murine brain tumors following radiation therapy

    Science.gov (United States)

    Feng, Y.; Clayton, E. H.; Okamoto, R. J.; Engelbach, J.; Bayly, P. V.; Garbow, J. R.

    2016-08-01

    An accurate and noninvasive method for assessing treatment response following radiotherapy is needed for both treatment monitoring and planning. Measurement of solid tumor volume alone is not sufficient for reliable early detection of therapeutic response, since changes in physiological and/or biomechanical properties can precede tumor volume change following therapy. In this study, we use magnetic resonance elastography to evaluate the treatment effect after radiotherapy in a murine brain tumor model. Shear modulus was calculated and compared between the delineated tumor region of interest (ROI) and its contralateral, mirrored counterpart. We also compared the shear modulus from both the irradiated and non-irradiated tumor and mirror ROIs longitudinally, sampling four time points spanning 9-19 d post tumor implant. Results showed that the tumor ROI had a lower shear modulus than that of the mirror ROI, independent of radiation. The shear modulus of the tumor ROI decreased over time for both the treated and untreated groups. By contrast, the shear modulus of the mirror ROI appeared to be relatively constant for the treated group, while an increasing trend was observed for the untreated group. The results provide insights into the tumor properties after radiation treatment and demonstrate the potential of using the mechanical properties of the tumor as a biomarker. In future studies, more closely spaced time points will be employed for detailed analysis of the radiation effect.

  2. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a {sup 60}Co Magnetic Resonance Image Guidance Radiation Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Wooten, H. Omar, E-mail: hwooten@radonc.wustl.edu; Green, Olga; Yang, Min; DeWees, Todd; Kashani, Rojano; Olsen, Jeff; Michalski, Jeff; Yang, Deshan; Tanderup, Kari; Hu, Yanle; Li, H. Harold; Mutic, Sasa

    2015-07-15

    Purpose: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating {sup 60}Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. Methods and Materials: The ViewRay treatment planning system (Oakwood Village, OH) was used to create {sup 60}Co IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives. Backup plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The {sup 60}Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses and heterogeneity indices (HI) for planning target volumes (PTVs) and maximum, mean, and dose-volume histogram (DVH) values for OARs. Results: All {sup 60}Co IMRT plans achieved PTV coverage and OAR sparing that were similar to linac plans. PTV conformity for {sup 60}Co was within <1% and 3% of linac plans for 100% and 95% prescription reference isodoses, respectively, and heterogeneity was on average 4% greater. Comparisons of OAR mean dose showed generally better sparing with linac plans in the low-dose range <20 Gy, but comparable sparing for organs with mean doses >20 Gy. The mean doses for all {sup 60}Co plan OARs were within clinical tolerances. Conclusions: A commercial {sup 60}Co MR-IGRT device can produce highly conformal IMRT treatment plans similar in quality to linac IMRT for a variety of disease sites. Additional work is in progress to evaluate the clinical benefit of other novel features of this MR-IGRT system.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chou Chau, Yuan-Fong, E-mail: chou.fong@ubd.edu.bn; Lim, Chee Ming; Kumara, N. T. R. N.; Yoong, Voo Nyuk [Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Tungku Link, Gadong BE1410, Brunei (Brunei Darussalam); Lee, Chuanyo [Department of Electronic Engineering, Chien Hsin University of Science and Technology, No. 229, Jianxing Rd., Zhongli City, Taoyuan County 32097, Taiwan (China); Huang, Hung Ji; Lin, Chun-Ting [Instrument Technology Research Center, National Applied Research Laboratories, Hsinchu, Taiwan (China); Chiang, Hai-Pang [Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung 202, Taiwan (China)

    2016-09-07

    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.

  4. A resonance Raman enhancement mechanism for axial vibrational modes in the pyridine adduct of myoglobin proximal cavity mutant (H93G).

    Science.gov (United States)

    Franzen, Stefan; Brown, Derek; Gaff, John; Delley, B

    2012-09-06

    The proximal cavity mutant of myoglobin consists of a mutation of the proximal histidine to glycine (H93G), which permits exogenous ligands to bind to the heme iron. A non-native pyridine ligand can ligate to the heme to yield a five-coordinate adduct, H93G(Pyr), that cannot be formed freely in solution since the six-coordinate bis-pyridine adduct is more stable than the five-coordinate adduct. We have used resonance Raman spectroscopy in the Soret band region of the heme to study the enhancement of axial vibrations of bound pyridine in the H93G(Pyr) adduct. The observation that the pyridine ring breathing mode (ν(1)) and the symmetric ring stretching (ν(3)) modes are enhanced under these conditions is explained by a computational approach that shows that coupling of the π-system of the heme with the p-orbitals of the pyridine is analogous to π-backbonding in diatomic ligand adducts of heme proteins. The result has the broader significance that it suggests that the resonance enhancement of pyridine modes could be an important aspect of Raman scattering of pyridine on conducting surfaces such as those studied in surface enhanced Raman scattering experiments.

  5. Effects of γ-ray radiation on two-dimensional molybdenum disulfide (MoS{sub 2}) nanomechanical resonators

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaesung; Feng, Philip X.-L., E-mail: philip.feng@case.edu [Department of Electrical Engineering and Computer Science, Case School of Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States); Krupcale, Matthew J. [Department of Electrical Engineering and Computer Science, Case School of Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States); Department of Physics, College of Arts and Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States)

    2016-01-11

    We report on experimental investigation and analysis of γ-ray radiation effects on two-dimensional molybdenum disulfide (MoS{sub 2}) drumhead nanomechanical resonators vibrating at megahertz frequencies. Given calibrated dosages of γ-ray radiation of ∼5000 photons with energy at 662 keV, upon exposure over 24 or 12 h, all the MoS{sub 2} resonators exhibit ∼0.5–2.1% resonance frequency upshifts due to the ionizing γ-ray induced charges and their interactions. The devices show γ-ray photon responsivity of ∼30–82 Hz/photon, with an intrinsic γ-ray sensitivity (limit of detection) estimated to approach ∼0.02–0.05 photon. After exposure expires, resonance frequencies return to an ordinary tendency where the frequency variations are dominated by long-term drift. These γ-ray radiation induced frequency shifts are distinctive from those due to pressure variation or surface adsorption mechanisms. The measurements and analyses show that MoS{sub 2} resonators are robust yet sensitive to very low dosage γ-ray, demonstrating a potential for ultrasensitive detection and early alarm of radiation in the very low dosage regime.

  6. Heat transfer study for convection and radiation in an open cavity; Estudio de de la transferencia de calor por convencion y radiacion en una cavidad abierta

    Energy Technology Data Exchange (ETDEWEB)

    Cabanillas Lopez, Rafael E [Universidad de Sonora, Hermosillo, Sonora (Mexico); Estrada Gasca, Claudio A [Centro de Investigacion en Energia-UNAM, Temixco, Morelos (Mexico); Alvarez Garcia, Gabriela S [CENIDET, Cuernavaca, Morelos (Mexico)

    2000-07-01

    Interaction of natural convection and radiation heat transfer in an open side square cavity has been simulated numerically. Previous studies have shown results of the simulation of heat transfer for convection on this geometry. This paper reports the effect of considering both the convection and the radiation mechanisms. Radiation was found to have a great influence on the total amount of heat lost by the cavity as well as on the pattern of flow and on the temperature field. Computations were performed within the domain of the cavity for two-dimensional laminar flow problem. The average of heat transfer coefficient was calculated for several values of the Grashof number for air (Pr = 0.7), with the bottom wall at 500 K (constant temperature) and the open side at 300 K. [Spanish] Se presenta el estudio de la interaccion conveccion natural-radiacion en una cavidad rectangular abierta. Algunos estudios anteriores han mostrado resultados sobre la transferencia de calor por el mecanismo de conveccion natural sobre cavidades abiertas. Aqui se presenta la influencia de considerar ambos mecanismos de transferencia de calor, la conveccion y la radiacion. Se demuestra que el intercambio radiactivo tiene una gran influencia tanto en la cantidad total de calor perdido por la cavidad al ambiente, como en el patron de flujo y de temperatura dentro de la cavidad. Se resuelven numericamente las ecuaciones gobernantes para flujo laminar en dos dimensiones y se calcula el coeficiente promedio de transferencia de calor para diferentes valores del Grashof en una cavidad llena de aire (Pr 0.7), teniendo la pared del fondo de la cavidad a 500 K y los alrededores a 300 K.

  7. Anticancer effects on leiomyosarcoma-bearing Wistar rats after electromagnetic radiation of resonant radiofrequencies.

    Science.gov (United States)

    Avdikos, Antonios; Karkabounas, Spyridon; Metsios, Apostolos; Kostoula, Olga; Havelas, Konstantinos; Binolis, Jayne; Verginadis, Ioannis; Hatziaivazis, George; Simos, Ioannis; Evangelou, Angelos

    2007-01-01

    In the present study, the effects of a resonant low intensity static electromagnetic field (EMF), causing no thermal effects, on Wistar rats have been investigated. Sarcoma cell lines were isolated from leiomyosarcoma tumors induced in Wistar rats by the subcutaneous (s.c) injection of 3,4-benzopyrene. Furthermore, smooth muscle cells (SMC) were isolated from the aorta of Wistar rats and cultivated. Either leiomyosarcoma cells (LSC) or SMC were used to record a number of characteristic resonant radiofrequencies, in order to determine the specific electromagnetic fingerprint spectrum for each cell line. These spectra were used to compose an appropriate algorithm, which transforms the recorded radiofrequencies to emitted ones. The isolated LSC were cultured and then exposed to a resonant low intensity radiofrequency EMF (RF-EMF), at frequencies between 10 kHz to 120 kHz of the radiowave spectrum. The exposure lasted 45 consecutive minutes daily, for two consecutive days. Three months old female Wistar rats were inoculated with exposed and non-exposed to EMF LSC (4 x 10(6) LCS for animal). Inoculated with non-exposed to EMF cells animals were then randomly separated into three Groups. The first Group was sham exposed to the resonant EMF (control Group-CG), the second Group after the inoculation of LSC and appearance of a palpable tumor mass, was exposed to a non-resonant EMF radiation pattern, for 5 h per day till death of all animals (experimental control Group-ECG). The third Group of animals after inoculation of LSC and the appearance of a palpable tumor mass, was exposed to the resonant EMF radiation for 5 h per day, for a maximum of 60 days (experimental Group-I, EG-I). A fourth Group of animals was inoculated with LSC exposed to EMF irradiation and were not further exposed to irradiation (experimental Group-II, EG-II). Tumor induction was 100% in all Groups studied and all tumors were histologically identified as leiomyosarcomas. In the case of the EG-I, a

  8. On limitation of quality factor of single mode resonators with finite size

    CERN Document Server

    Ferdous, Fahmida; Vyatchanin, Sergey P; Matsko, Andrey B; Maleki, Lute

    2014-01-01

    Using realistic numerical models we analyze radiative loss of bound and unbound modes of specially designed high-Q whispering gallery and Fabry-Perot cavities of similar size and shape, and find a set of parameters when they can be treated as single mode structures. We show that these cavities have similar properties in spite of their different loss mechanisms. The cavity morphology engineering does not lead to reduction of the resonator quality factor.

  9. Nanoantenna enhanced emission of light-harvesting complex 2: the role of resonance, polarization, and radiative and non-radiative rates.

    Science.gov (United States)

    Wientjes, Emilie; Renger, Jan; Curto, Alberto G; Cogdell, Richard; van Hulst, Niek F

    2014-12-01

    Nanoantennae show potential for photosynthesis research for two reasons; first by spatially confining light for experiments which require high spatial resolution, and second by enhancing the photon emission of single light-harvesting complexes. For effective use of nanoantennae a detailed understanding of the interaction between the nanoantenna and the light-harvesting complex is required. Here we report how the excitation and emission of multiple purple bacterial LH2s (light-harvesting complex 2) are controlled by single gold nanorod antennae. LH2 complexes were chemically attached to such antennae, and the antenna length was systematically varied to tune the resonance with respect to the LH2 absorption and emission. There are three main findings. (i) The polarization of the LH2 emission is fully controlled by the resonant nanoantenna. (ii) The largest fluorescence enhancement, of 23 times, is reached for excitation with light at λ = 850 nm, polarized along the long antenna-axis of the resonant antenna. The excitation enhancement is found to be 6 times, while the emission efficiency is increased 3.6 times. (iii) The fluorescence lifetime of LH2 depends strongly on the antenna length, with shortest lifetimes of ∼40 ps for the resonant antenna. The lifetime shortening arises from an 11 times resonant enhancement of the radiative rate, together with a 2-3 times increase of the non-radiative rate, compared to the off-resonant antenna. The observed length dependence of radiative and non-radiative rate enhancement is in good agreement with simulations. Overall this work gives a complete picture of how the excitation and emission of multi-pigment light-harvesting complexes are influenced by a dipole nanoantenna.

  10. Theoretical and experimental researches on C-band three-cavity transit-time effect oscillator

    Institute of Scientific and Technical Information of China (English)

    FAN Zhikai; LIU Qingxiang; CHEN Daibing; TAN Jie; ZHOU Haijing

    2004-01-01

    The C-band three-cavity transit-time effect oscillator (3C TTTO) is a novel high power microwave device based on the transit-time effect of the three-cavity (3C) resonator. The operational principle of this device is briefly expounded in this paper, and the theoretical and experimental researches on the radial insulation diode, the 3C resonator, the double-gap output cavity and the circular waveguide bevel cut radiation antenna are presented in detail. By using the analytic method, the eigen modes and their field distributions of the 3C resonator are developed, and some basic laws of the transit-time effect are obtained in non-( mode field of the 3C resonator. At last, the experimental results are given. This device generated RF peak power in excess of 400MW with 15ns FWHM, and its beam-wave power conversion efficiency is about 17%.

  11. Cavity magnomechanics

    Science.gov (United States)

    Zou, Chang-Ling; Zhang, Xufeng; Jiang, Liang; Tang, Hong

    2016-05-01

    Recently, cavity magnonics has attracted much attention for potential applications of coherent information transduction and hybrid quantum devices. The magnon is a collective spin wave excitation in ferromagnetic material. It is magnetically tunability, with long coherence time and non-reciprocical interaction with electro-magnetic fields. We report the coherent coupling between magnon, microwave photon and phonon. First, we demonstrate strong coupling and ultrastrong coupling between the magnon in YIG sphere and microwave photon in three-dimensional cavity. Then, based on the hybridized magnon-photon modes, we observe the triply resonant magnon-mcirowave photon-phonon coupling, where the ultrahigh-Q mechanical vibration of YIG sphere is dispersively coupled with the magnon via magnetostrictive interaction. We observe interesting phenomena, including electromagnetically induced transparency/absorption and parametric amplification. In particular, benefit from the large tunability of the magnon, we demonstrate a tunable microwave amplifier with gain as high as 30 dB. The single crystal YIG also has excellent optical properties, and thus provide a unique platform bridging MHz, GHz and THz information carriers. Finally, we present the latest progress towards coherent magnon to optical photon conversion.

  12. Nonlinear fundamental and harmonic cyclotron resonant scattering of radiation belt ultrarelativistic electrons by oblique monochromatic EMIC waves

    Science.gov (United States)

    Wang, Geng; Su, Zhenpeng; Zheng, Huinan; Wang, Yuming; Zhang, Min; Wang, Shui

    2017-02-01

    Cyclotron resonant scattering by electromagnetic ion cyclotron (EMIC) waves has been considered to be responsible for the rapid loss of radiation belt high-energy electrons. For parallel-propagating EMIC waves, the nonlinear character of cyclotron resonance has been revealed in recent studies. Here we present the first study on the nonlinear fundamental and harmonic cyclotron resonant scattering of radiation belt ultrarelativistic electrons by oblique EMIC waves on the basis of test particle simulations. Higher wave obliquity produces stronger nonlinearity of harmonic resonances but weaker nonlinearity of fundamental resonance. Compared to the quasi-linear prediction, these nonlinear resonances yield a more rapid loss of electrons over a wider pitch angle range. In the quasi-linear regime, the ultrarelativistic electrons are lost in the equatorial pitch angle range αeq87.5° at ψ = 20° and 40°. At the resonant pitch angles αeq<75°, the difference between quasi-linear and nonlinear loss timescales tends to decrease with the wave normal angle increasing. At ψ = 0° and 20°, the nonlinear electron loss timescale is 10% shorter than the quasi-linear prediction; at ψ = 40°, the difference in loss timescales is reduced to <5%.

  13. Change of electrical conductivity of Ar welding arc under resonant absorption of laser radiation

    Science.gov (United States)

    Kozakov, R.; Emde, B.; Pipa, A. V.; Huse, M.; Uhrlandt, D.; Hermsdorf, J.; Wesling, V.

    2015-03-01

    Experimental investigations of the impact of resonant laser absorption by a tungsten inert gas welding arc in argon are presented. The intensity increase of the arc’s radiation between the laser entrance height and the anode are observed, as well as the variation of arc voltage due to the presence of the laser beam. High-speed camera recordings from different directions combined with absolutely calibrated spectroscopic measurements allow the reconstruction of the three-dimensional emission coefficient profiles without the assumption of axial symmetry. The obtained data are evaluated within the framework of local thermodynamic equilibrium. The local increase in the temperature and conductivity due to the influence of the laser is determined. Changes in the electrical conductivity obtained from the optical measurements coincide well with the measured voltage drop, and show significant redistribution of the current density profile near the anode in particular.

  14. Effect of radiation and temperature on resonance properties of polyurethane-coated wire bonds

    Science.gov (United States)

    Izen, J. M.; Chen, Y.; Kurth, M.

    2017-04-01

    Thin polyurethane (PU) coatings for aluminum wedge wire bonds are proposed to protect the ATLAS Inner Tracker upgrade from oscillations from periodic Lorentz forces and condensation-induced corrosion. Coating robustness after exposure to lifetime doses expected by parts of a tracking detector at the High Luminosity-Large Hadron Collider has been evaluated. Mechanical properties of irradiated samples were tested at room temperature and at 0-2° C. Irradiated samples were thermal-cycled to test for radiation-induced intolerance to thermal expansion. Mechanical vibrations of PU-coated wire bonds (99% aluminum, 1% silicon, 25 μ m diameter) were excited with 50% duty-cycle square wave currents in a 1.0 T field. The most vulnerable endcap disk geometry (magnetic field perpendicular to the wire bond and parallel to the normal of its PC board) was used. Resonance characteristics have been measured up to anticipated lifetime doses.

  15. Radioanalytical prediction of radiative capture in 99Mo production via transmutation adiabatic resonance crossing by cyclotron

    CERN Document Server

    Khorshidi, Abdollah; Pazirandeh, Ali; Tenreiro, Claudio; Kadi, Yacine

    2014-01-01

    In this study, the transmutation adiabatic resonance crossing (TARC) concept was estimated in Mo-99 radioisotope production via radiative capture reaction in two designs. The TARC method was composed of moderating neutrons in lead or a composition of lead and water. Additionally, the target was surrounded by a moderator assembly and a graphite reflector district. Produced neutrons were investigated by (p,xn) interactions with 30 MeV and 300 mu A proton beam on tungsten, beryllium, and tantalum targets. The Mo-99 production yield was related to the moderator property, cross section, and sample positioning inside the distinct region of neutron storage as must be proper to achieve gains. Gathered thermal flux of neutrons can contribute to molybdenum isotope production. Moreover, the sample positioning to gain higher production yield was dependent on a greater flux in the length of thermal neutrons and region materials inside the moderator or reflector. When the sample radial distance from Be was 38 cm inside the...

  16. Dual Strip-Excited Dielectric Resonator Antenna with Parasitic Strips for Radiation Pattern Reconfigurability

    Directory of Open Access Journals (Sweden)

    M. Kamran Saleem

    2014-01-01

    Full Text Available A novel pattern reconfigurable antenna concept utilizing rectangular dielectric resonator antenna (DRA placed over dielectric substrate backed by a ground plane is presented. A dual strip excitation scheme is utilized and both excitation strips are connected together by means of a 50 Ω microstrip feed network placed over the substrate. The four vertical metallic parasitic strips are placed at corner of DRA each having a corresponding ground pad to provide a short/open circuit between the parasitic strip and antenna ground plane, through which a shift of 90° in antenna radiation pattern in elevation plane is achieved. A fractional bandwidth of approximately 40% at center frequency of 1.6 GHz is achieved. The DRA peak realized gain in whole frequency band of operation is found to be above 4 dB. The antenna configuration along with simulation and measured results are presented.

  17. Controlling spin relaxation with a cavity

    Science.gov (United States)

    Bienfait, A.; Pla, J. J.; Kubo, Y.; Zhou, X.; Stern, M.; Lo, C. C.; Weis, C. D.; Schenkel, T.; Vion, D.; Esteve, D.; Morton, J. J. L.; Bertet, P.

    2016-03-01

    Spontaneous emission of radiation is one of the fundamental mechanisms by which an excited quantum system returns to equilibrium. For spins, however, spontaneous emission is generally negligible compared to other non-radiative relaxation processes because of the weak coupling between the magnetic dipole and the electromagnetic field. In 1946, Purcell realized that the rate of spontaneous emission can be greatly enhanced by placing the quantum system in a resonant cavity. This effect has since been used extensively to control the lifetime of atoms and semiconducting heterostructures coupled to microwave or optical cavities, and is essential for the realization of high-efficiency single-photon sources. Here we report the application of this idea to spins in solids. By coupling donor spins in silicon to a superconducting microwave cavity with a high quality factor and a small mode volume, we reach the regime in which spontaneous emission constitutes the dominant mechanism of spin relaxation. The relaxation rate is increased by three orders of magnitude as the spins are tuned to the cavity resonance, demonstrating that energy relaxation can be controlled on demand. Our results provide a general way to initialize spin systems into their ground state and therefore have applications in magnetic resonance and quantum information processing. They also demonstrate that the coupling between the magnetic dipole of a spin and the electromagnetic field can be enhanced up to the point at which quantum fluctuations have a marked effect on the spin dynamics; as such, they represent an important step towards the coherent magnetic coupling of individual spins to microwave photons.

  18. Photon strength functions in Gd isotopes studied from radiative capture of resonance neutrons

    Directory of Open Access Journals (Sweden)

    Kroll J.

    2014-04-01

    Full Text Available The experimental spectra of γ rays following radiative neutron capture on isolated resonances of stable 152,154–158Gd targets were measured by the DANCE calorimeter installed at the Los Alamos Neutron Scattering Center in New Mexico, USA. These spectra were analyzed within the extreme statistical model to get new information on the photon strength functions. Special emphasis was put on study of the scissors vibrational mode present in these isotopes. Our data show that the scissors-mode resonances are built not only on the ground states but also on the excited levels of all studied Gd isotopes. The scissors mode strength observed in 157,159Gd products is significantly higher than in neighboring even-even nuclei 156,158Gd. Such a difference indicates the existence of an odd-even effect in the scissors mode strength. Moreover, there exists no universal parameter-free model of the electric dipole photon strength function describing the experimental data in all of the Gd isotopes studied. The results for the scissors mode are compared with the (γ, γ′ data for the ground-state transitions and with the results from 3He-induced reactions.

  19. Purcell effect in Hyperbolic Metamaterial Resonators

    CERN Document Server

    Slobozhanyuk, Alexey P; Powell, David A; Iorsh, Ivan; Shalin, Alexander S; Segovia, Paulina; Krasavin, Alexey V; Wurtz, Gregory A; Podolskiy, Viktor A; Belov, Pavel A; Zayats, Anatoly V

    2015-01-01

    The radiation dynamics of optical emitters can be manipulated by properly designed material structures providing high local density of photonic states, a phenomenon often referred to as the Purcell effect. Plasmonic nanorod metamaterials with hyperbolic dispersion of electromagnetic modes are believed to deliver a significant Purcell enhancement with both broadband and non-resonant nature. Here, we have investigated finite-size cavities formed by nanorod metamaterials and shown that the main mechanism of the Purcell effect in these hyperbolic resonators originates from the cavity hyperbolic modes, which in a microscopic description stem from the interacting cylindrical surface plasmon modes of the finite number of nanorods forming the cavity. It is found that emitters polarized perpendicular to the nanorods exhibit strong decay rate enhancement, which is predominantly influenced by the rod length. We demonstrate that this enhancement originates from Fabry-Perot modes of the metamaterial cavity. The Purcell fa...

  20. Super-Resonant Intracavity Coherent Absorption

    CERN Document Server

    Malara, P; Giorgini, A; Avino, S; De Natale, P; Gagliardi, G

    2016-01-01

    The capability of optical resonators to extend the effective radiation-matter interaction length originates from a multipass effect, hence is intrinsically limited by the resonator quality factor. Here, we show that this constraint can be overcome by combining the concepts of resonant interaction and coherent perfect absorption. We demonstrate and investigate super-resonant coherent absorption in a coupled Fabry-Perot-ring cavity structure. At the FP resonant wavelengths, the described phenomenon gives rise to split modes with a nearly-transparent peak and a peak whose transmission is exceptionally sensitive to the intracavity loss. For small losses, the effective interaction pathlength of these modes is proportional respectively to the ratio and the product of the individual finesse coefficients of the two resonators. The results presented extend the conventional definition of resonant absorption and point to a way of circumventing the technological limitations of ultrahigh-quality resonators in spectroscopy...

  1. Current Role and Future Perspectives of Magnetic Resonance Spectroscopy in Radiation Oncology for Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Aleksandra Zapotoczna

    2007-06-01

    Full Text Available Prostatic neoplasms are not uniformly distributed within the prostate volume. With recent developments in three-dimensional intensity-modulated and imageguided radiation therapy, it is possible to treat different volumes within the prostate to different thresholds of doses. This approach has the potential to adapt the dose to the biologic aggressiveness of various clusters of tumor cells within the gland. The definition of tumor burden volume in prostate cancer can be facilitated by the use of magnetic resonance spectroscopy (MRS. The increasing sensitivity and specificity of MRS to the prostate is causing new interest in its potential role in the definition of target subvolumes at higher risk of failure following radical radiotherapy. Prostate MRS might also play a role as a noninvasive predictive factor for tumor response and treatment outcome. We review the use of MRS in radiation therapy for prostate cancer by evaluating its accuracy in the classification of aggressive cancer regions and target definition; its current role in the radiotherapy planning process, with special interest in technical issues behind the successful inclusion of MRS in clinical use; and available early experiences as a prognostic tool.

  2. Radiation damping and reciprocity in nuclear magnetic resonance: the replacement of the filling factor.

    Science.gov (United States)

    Tropp, James; Van Criekinge, Mark

    2010-09-01

    The basic equation describing radiation damping in nuclear magnetic resonance (NMR) is rewritten by means of the reciprocity principle, to remove the dependence of the damping constant upon filling factor - a parameter which is neither uniquely defined for easily measured. The new equation uses instead the transceive efficiency, i.e. the peak amplitude of the radiofrequency B field in laboratory coordinates, divided by the square root of the resistance of the detection coil, for which a simple and direct means of measurement exists. We use the efficiency to define the intrinsic damping constant, i.e. that which obtains when both probe and preamplifier are perfectly matched to the system impedance. For imperfect matching of the preamp, it is shown that the damping constant varies with electrical distance to the probe, and equations are given and simulations performed, to predict the distance dependence, which (for lossless lines) is periodic modulo a half wavelength. Experimental measurements of the radiation-damped free induction NMR signal of protons in neat water are performed at a static B field strength of 14.1T; and an intrinsic damping constant measured using the variable line method. For a sample of 5mm diameter, in an inverse detection probe we measure an intrinsic damping constant of 204 s(-1), corresponding to a damping linewidth of 65 Hz for small tip angles. The predicted intrinsic linewidth, based upon three separate measurements of the efficiency, is 52.3 Hz, or 80% of the measured value.

  3. Nonlinear optical detection of terahertz-wave radiation from resonant tunneling diodes.

    Science.gov (United States)

    Takida, Yuma; Nawata, Kouji; Suzuki, Safumi; Asada, Masahiro; Minamide, Hiroaki

    2017-03-06

    The sensitive detection of terahertz (THz)-wave radiation from compact sources at room temperature is crucial for real-world THz-wave applications. Here, we demonstrate the nonlinear optical detection of THz-wave radiation from continuous-wave (CW) resonant tunneling diodes (RTDs) at 0.58, 0.78, and 1.14 THz. The up-conversion process in a MgO:LiNbO3 crystal under the noncollinear phase-matching condition offers efficient wavelength conversion from a THz wave to a near-infrared (NIR) wave that is detected using a commercial NIR photodetector. The minimum detection limit of CW THz-wave power is as low as 5 nW at 1.14 THz, corresponding to 2-aJ energy and 2.7 × 103 photons within the time window of a 0.31-ns pump pulse. Our results show that the input frequency and power of RTD devices can be calibrated by measuring the output wavelength and energy of up-converted waves, respectively. This optical detection technique for compact electronic THz-wave sources will open up a new opportunity for the realization of real-world THz-wave applications.

  4. Theory of a Directive Optical Leaky Wave Antenna Integrated into a Resonator and Enhancement of Radiation Control

    CERN Document Server

    Guclu, Caner; Boyraz, Ozdal; Capolino, Filippo

    2013-01-01

    We provide for the first time the detailed study of the radiation performance of an optical leaky wave antenna (OLWA) integrated into a Fabry-P\\'erot resonator. We show that the radiation pattern can be expressed as the one generated by the interference of two leaky waves counter-propagating in the resonator leading to a design procedure for achieving optimized broadside radiation, i.e., normal to the waveguide axis. We thus report a realizable implementation of the OLWA made of semiconductor and dielectric regions. The theoretical modeling is supported by full-wave simulation results, which are found to be in good agreement. We aim to control the radiation intensity in the broadside direction via excess carrier generation in the semiconductor regions. We show that the presence of the resonator can provide an effective way of enhancing the radiation level modulation, which reaches values as high as 13.5 dB, paving the way for novel promising control capabilities that might allow the generation of very fast op...

  5. Entanglement swapping between atom and cavity and generation of entangled state of cavity fields

    Institute of Scientific and Technical Information of China (English)

    Chen Ai-Xi; Deng Li

    2007-01-01

    This paper proposes a scheme where entanglement swapping between atom and cavity can be realized. A-type three-level atoms interacting resonantly with cavity field are considered. By detecting atom and cavity field, it realizes entanglement swapping between atom and cavity. It uses the technique of entanglement swapping to generate an entangled state of two cavity fields by measuring on atoms. It discusses the experimental feasibility of the proposed scheme and application of entangled state of cavity fields.

  6. 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...

  7. Experimental Verification of Isotropic Radiation from a Coherent Dipole Source via Electric-Field-Driven LC Resonator Metamaterials

    Science.gov (United States)

    Tichit, Paul-Henri; Burokur, Shah Nawaz; Qiu, Cheng-Wei; de Lustrac, André

    2013-09-01

    It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator’s gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present.

  8. 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.

  9. Improvement of the matching speed of AIMS for development of an automatic totally tuning system for hyperthermia treatment using a resonant cavity applicator.

    Science.gov (United States)

    Shindo, Y; Kato, K; Tsuchiya, K; Hirashima, T; Suzuki, M

    2009-01-01

    In this paper, we discuss the improvement of the speed of AIMS (Automatic Impedance Matching System) to automatically make impedance matching for a re-entrant resonant cavity applicator for non-invasive deep brain tumors hyperthermia treatments. We have already discussed the effectiveness of the heating method using the AIMS, with experiments of heating agar phantoms. However, the operating time of AIMS was about 30 minutes. To develop the ATT System (Automatic Totally Tuning System) including the automatic frequency tuning system, we must improve this problem. Because, when using the ATTS, the AIMS is used repeatedly to find the resonant frequency. In order to improve the speed of impedance matching, we developed the new automatic impedance matching system program (AIMS2). In AIMS, the stepping motors were connected to the impedance matching unit's dials. These dials were turned to reduce the reflected power. AIMS consists of two phases: all range searching and detailed searching. We focused on the three factors affecting the operating speed and improved them. The first factor is the interval put between the turning of the motors and AD converter. The second factor is how the steps of the motor when operating all range searching. The third factor is the starting position of the motor when detail searching. We developed the simple ATT System (ATT-beta) based on the AIMS2. To evaluate the developed AIMS2 and ATT- beta, experiments with an agar phantom were performed. From these results, we found that the operating time of the AIMS2 is about 4 minutes, which was approximately 12% of AIMS. From ATT-beta results, it was shown that it is possible to tune frequency and automatically match impedance with the program based on the AIMS2.

  10. 铁路混凝土箱梁箱内空腔共鸣噪声及其影响研究%Study on Cavity Resonance Noise of Railway Concrete Box-Girder and Its Influence

    Institute of Scientific and Technical Information of China (English)

    张迅; 王党雄; 李小珍

    2015-01-01

    为探讨铁路混凝土箱梁箱内空腔共鸣噪声及其影响,以某客运专线32 m预应力混凝土简支箱梁为研究对象,开展实桥振动与噪声试验,分析箱梁振动与噪声的时域特性及频谱特性。采用有限元法建立三维空腔声模型,分析箱内空腔声模态与腔内噪声峰值的关联性。采用边界元法分别建立两端封闭与两端开口的箱梁声学模型,验证箱内空腔共鸣噪声的来源及其影响。结果表明:在特定行车速度下,箱内噪声出现“拍”现象,显著增大箱内噪声,瞬时最大声压可达40 Pa,峰值频率为75.0 Hz;箱内噪声的“拍”现象来源于顶板的振动噪声,顶板的振动峰值频率与箱内空腔垂向声模态频率吻合时,箱内噪声显著增大;由于梁缝的声泄漏特性,箱内空腔共鸣噪声在梁缝处衰减较大,但其对桥梁两侧总体噪声的影响不可忽略。%In order to study the cavity resonance noise of concrete box-girder and its influence,a field test con-cerning vibration and noise of a 32 m PC simply-supported box-girder was carried out,to investigate the time-domain characteristics and frequency spectrum characteristics of vibration and noise of the box-girder.A 3D cavity acoustical model was established based on FEM to analyze the correlation between cavity acoustic mode and cavity noise peak.Two acoustical models for box-girders with closed ends and open ends,were built based on BEM,respectively,to verify the source and influence of cavity resonance noise.Results showed that the“beat”wave phenomenon of cavity noise appeared under a specific train speed,significantly increasing the cavi-ty noise,with the transient maximum sound pressure of cavity noise reaching 40 Pa and the noise peak frequen-cy being 75.0 Hz;The “beat”wave phenomenon of cavity noise derived from the vibration of deck.When the peak vibration frequency of deck matched with the frequency of vertical acoustic modal of the cavity

  11. Ultraintense short-wavelength emission from ZnO-sheathed MgO nanorods induced by subwavelength optical resonance cavity formation: verification of previous hypothesis.

    Science.gov (United States)

    Jin, Changhyun; Kim, Hyunsu; Lee, Chongmu

    2012-03-01

    A recent paper reported that intense emissions with a range of wavelengths over a wide spectral range, from ultraviolet to infrared light, might be possible by sheathing MgO nanorods with a semiconducting material with an optimal sheath thickness. In addition, the paper hypothesized that an ultraintense short-wavelength emission could be obtained by sheathing MgO nanorods with a ~17 nm ZnO thin film in the paper. In this study, we found that the intensity ratio of the near-band edge emission to the deep level emission (I(NBE)/I(DL)) of the MgO-core/ZnO-shell nanorods with a mean shell layer thickness of 17 nm was as high as ~30, whereas the I(NBE)/I(DL) ratio of the bare-MgO nanorods was 0. This near-band edge emission intensity enhancement by sheathing the MgO nanorods with ZnO is by far more significant than that by sheathing the ZnO nanorods with other materials including MgO. This is because subwavelength optical resonance cavities form in the MgO-core/ZnO-shell nanorods with faceted surfaces, whereas they do not form in the ZnO-core/MgO (or other material)-shell nanorods with no faceted surfaces.

  12. Dielectric properties of oil sands at 2.45 GHz with TE1,0,11 mode determined by a rectangular cavity resonator.

    Science.gov (United States)

    Erdogan, Levent; Akyel, Cevdet; Ghannouchi, Fadhel M

    2011-01-01

    Oil obtained from oil sands resources constitute an important portion of the oil industry in Canada. Extraction of the bitumen from oil sands is very crucial process because of its cost and environmental impact. Microwave energy applicators by heating oil sands at microwave frequencies can be an excellent alternative to extract bitumen with the advantages of being potentially cost-effective and environmentally friendly method of extraction. In order to design and manufacture a microwave energy applicator, its dielectric properties must be known. In this study, as the first part of our ultimate microwave energy applicator project, in advance, the complex permittivity of oil sands was measured by using rectangular cavity resonator, designed and fabricated in Ecole Polytechnique de Montréal laboratories, at 2.45 GHz with TE1,0,1 mode. The accuracy of the permittivity measurement results obtained with the developed system was verified against those obtained using a commercial open-ended probe system as well the values of well known materials documented in open literature. Since there is no study found in the literature about the complex permittivity values of oil sands at 2.45 GHz, the present study would be of great help and important guide for those who plan to design and manufacture microwave energy applicators in order to extract the bitumen from the oil sands.

  13. GaInNAs/GaAs Multiple-Quantum Well Resonant-Cavity-Enhanced Photodetectors at 1.3μm

    Institute of Scientific and Technical Information of China (English)

    潘钟; 李联合; 徐应强; 张伟; 林耀望; 张瑞康; 钟源; 任晓敏

    2001-01-01

    A GaInNAs/GaAs multiple quantum well (MQW) resonant-cavity enhanced photodetector (RCE-PD) operated at a wavelength of 1.3μm with the full width at half maximum of 4nm has been demonstrated. The GaInNAs RCE-PD was grown by molecular beam epitaxy using a homemade ion-removed dc plasma cell as a nitrogen source. GaInNAs/GaAs MQW shows a strong exciton peak at room temperature, which is very beneficial for applications in long-wavelength absorption devices. For a 100μm diameter RCE-PD, the dark current is 20 and 32 pA at biases of 0 and 6 V, respectively, and the breakdown voltage is -18 V. The measured 3 dB bandwidth is 308 MHz, which is limited by the resistance of p-type distributed Bragg reflector mirror. The tunable wavelength in a range of 18nm with the angle of incident light was observed.

  14. 水中矩形板的共振声辐射%Resonance sound radiation of submerged rectangular plate

    Institute of Scientific and Technical Information of China (English)

    程钊; 范军; 王斌; 汤渭霖

    2013-01-01

    研究共振声辐射理论(Resonance Radiation Theory:RRT)在水中矩形板的应用.导出了矩形板的共振声辐射公式、并数值验证了其适用性.深入分析了有流体负荷矩形板的复共振频率的物理意义及其与导纳留数、模态辐射率的关系,复共振频率的实部表示实际共振频率,虚部反映模态辐射能力.根据复共振频率容易找到辐射能力相对较强的模态,为有针对性控制声辐射提供了新的思路.鉴于复平面搜根求解模态复共振频率的困难,针对矩形板的特点提出了一种求解复共振频率及留数的快速方法.结合该方法及RRT,提出了一种快速计算辐射声功率的方法,数值验证表明该方法精度高、速度快.%The application of Resonance Radiation Theory (RRT) for submerged rectangular plates was investigated. The RRT formula of the rectangular plate was derived and validated numerically. For fluid loaded rectangular plates, the physical essence of the complex resonant frequency, and the relationship of which with residue of the reactance and modal radiation efficiency were deeply analyzed. The real part of complex resonant frequency represents the actual modal natural frequency, and the imagine part determines modal radiation ability. It is easy to find the mode whose radiation ability is relatively strong, which leads to an idea to targeted control of the sound radiation. Since the difficulty in solving complex resonance frequency by the method of searching in complex plane, an efficient method for solving complex resonance frequencies and residues of plates was presented. On the basis of the method and RRT, a tool for predicting rapidly and efficiently the radiated sound power of rectangular plates was proposed and validated numerically.

  15. The value of multimodal magnetic resonance imaging in the differential diagnosis of glioma recurrence and radiation brain injury

    Directory of Open Access Journals (Sweden)

    Guang-zhi GE

    2015-11-01

    Full Text Available Objective  To explore the application of a combination of diFFusion weighted imaging (DWI, perfusion weighted imaging (PWI and magnetic resonance spectroscopy (MRS in the differential diagnosis of glioma recurrence and radiation brain injury. Methods The clinical and imaging data of 32 patients were retrospectively analyzed, including 15 cases of glioma recurrence and 17 cases of radiation brain injury, admitted from Jan. 2011 to Dec. 2013 in General Hospital of Beijing Command. The DWI, PWI and MRS data of the 32 patients were retrospectively analyzed. The following values were compared between abnormal enhancement area and contralateral normal area: magnetic resonance apparent diFFusion coeFFcient (ADC, relative cerebral blood flow (rCBF, relative cerebral blood volume (rCBV, relative mean transit time (rMTT, choline/creatine (Cho/Cr and choline/N-acetyl aspartate (Cho/ NAA ratio. Results No statistical significance of ADC and rMTT values was found between glioma recurrence group and radiation brain injury group (P>0.05; The maximum and average rCBF and rCBV values were significantly higher in glioma recurrence group than in radiation brain injury group (P0.05. The ratios of Cho/Cr and Cho/NAA were higher in glioma recurrence group than in radiation brain injury group (P<0.05. The diagnostic sensitivity of PWI to glioma recurrence was 80.0%, of MRS was 73.3%, and of PWI combined with MRS was 93.3%. The diagnostic sensitivity of PWI to radiation brain injury was 82.4%, of MRS was 70.6%, and of PWI combined with MRS was 88.2%. Conclusion Combined application of multimodal magnetic resonance imaging technology may improve the diagnostic accuracy to glioma recurrence and radiation brain injury, thus provide a good guidance for clinical treatment. DOI: 10.11855/j.issn.0577-7402.2015.11.13

  16. X-Ray Polarization Optics and Coherent Nuclear Resonance Scattering Using Synchrotron Radiation.

    Science.gov (United States)

    Shastri, Sarvjit Devdat

    1995-01-01

    Two projects, both involving X-ray scattering with synchrotron radiation, are presented in this dissertation. (1) A system of diffracting perfect crystals for the generation of variable, elliptically polarized X-rays was tested at the Cornell High Energy Synchrotron Source under the conditions of a standard undulator source. The phase retarding optical component was a 4-bounce, Ge(220) Bragg reflection channel -cut crystal. The full polarization state (density matrix) of the output beam, including the circular polarization purity P_3, was determined using the multiple-beam Bragg diffraction technique with a GaAs crystal polarimeter and was found to agree with calculations. In addition to measuring the optics' efficiency, the ability to scan the system in energy, while frequently reversing the circular helicity, was demonstrated at the vicinity of the Fe K-edge at 7.1 keV. The setup was applied to a circular magnetic X-ray dichroism measurement. (2) The time distribution of delayed photons from resonant forward scattering of 14.4 keV synchrotron radiation pulses by ^{57}Fe nuclei was investigated over the temperature range from 9 K to just above the Curie point at 1043 K, with particular attention to precise measurements of the Lamb-Mossbauer factor f_{LM } ~ e^{- } , whose change was determined from its influence on the "speed-up" of coherent decay. Apart from its importance in Mossbauer effect studies, knowing the temperature dependence of f_{LM} can be valuable for studies of lattice dynamics and structural phase transitions. The change in the nuclear hyperfine splitting was also measured. The synchrotron technique has precision-enhancing advantages over conventional Mossbauer spectroscopy methods employing radioactive sources because dealing with source effects and absolute intensity measurements is eliminated. The results also straightforwardly illustrate an interesting principle concerning the temperature dependence of scattering --that for "slow" resonance

  17. Retrospective assessment of radiation exposure using biological dosimetry: chromosome painting, electron paramagnetic resonance and the glycophorin a mutation assay.

    Science.gov (United States)

    Kleinerman, R A; Romanyukha, A A; Schauer, D A; Tucker, J D

    2006-07-01

    Biological monitoring of dose can contribute important, independent estimates of cumulative radiation exposure in epidemiological studies, especially in studies in which the physical dosimetry is lacking. Three biodosimeters that have been used in epidemiological studies to estimate past radiation exposure from external sources will be highlighted: chromosome painting or FISH (fluorescence in situ hybridization), the glycophorin A somatic mutation assay (GPA), and electron paramagnetic resonance (EPR) with teeth. All three biodosimeters have been applied to A-bomb survivors, Chernobyl clean-up workers, and radiation workers. Each biodosimeter has unique advantages and limitations depending upon the level and type of radiation exposure. Chromosome painting has been the most widely applied biodosimeter in epidemiological studies of past radiation exposure, and results of these studies provide evidence that dose-related translocations persist for decades. EPR tooth dosimetry has been used to validate dose models of acute and chronic radiation exposure, although the present requirement of extracted teeth has been a disadvantage. GPA has been correlated with physically based radiation dose after high-dose, acute exposures but not after low-dose, chronic exposures. Interindividual variability appears to be a limitation for both chromosome painting and GPA. Both of these techniques can be used to estimate the level of past radiation exposure to a population, whereas EPR can provide individual dose estimates of past exposure. This paper will review each of these three biodosimeters and compare their application in selected epidemiological studies.

  18. Experimental research on cavity resonance based on sound card and MMUSE software%基于声卡和MMUSE软件的空腔共振实验研究

    Institute of Scientific and Technical Information of China (English)

    吴肖; 熊建文

    2016-01-01

    This paper introduces the application of a free and open-source software called MMUSE in researching cavity resonance based on the computer sound card.This experimental method can measure the resonant frequency accurately and test the resonance frequency formula according to the theory of Helmholtz resonance.%介绍了以科学教育多媒体软件 MMUSE(multimedia utilities for science education)为平台,基于声卡为采集系统进行的空腔共振实验研究,精确地测量了烧杯等空腔的共振频率,对赫姆霍兹共振子理论下的空腔共振频率公式进行了验证。

  19. RF and Data Acquisition Systems for Fermilab's ILC SRF Cavity Vertical Test Stand

    Energy Technology Data Exchange (ETDEWEB)

    Joseph P. Ozelis; Roger Nehring; Christiana Grenoble; Thomas J. Powers

    2007-06-01

    Fermilab is developing a facility for vertical testing of SRF cavities as part of a program to improve cavity performance reproducibility for the ILC. The RF system for this facility, using the classic combination of oscillator, phase detector/mixer, and loop amplifier to detect the resonant cavity frequency and lock onto the cavity, is based on the proven production cavity test systems used at Jefferson Lab for CEBAF and SNS cavity testing. The design approach is modular in nature, using commercial-off-the-shelf (COTS) components. This yields a system that can be easily debugged and modified, and with ready availability of spares. Data acquisition and control is provided by a PXI-based hardware platform in conjunction with software developed in the LabView programming environment. This software provides for amplitude and phase adjustment of incident RF power, and measures all relevant cavity power levels, cavity thermal environment parameters, as well as field emission-produced radiation. It also calculates the various cavity performance parameters and their associated errors. Performance during system commissioning and initial cavity tests will be presented.

  20. Super-Resonant Intracavity Coherent Absorption

    Science.gov (United States)

    Malara, P.; Campanella, C. E.; Giorgini, A.; Avino, S.; de Natale, P.; Gagliardi, G.

    2016-07-01

    The capability of optical resonators to extend the effective radiation-matter interaction length originates from a multipass effect, hence is intrinsically limited by the resonator’s quality factor. Here, we show that this constraint can be overcome by combining the concepts of resonant interaction and coherent perfect absorption (CPA). We demonstrate and investigate super-resonant coherent absorption in a coupled Fabry-Perot (FP)/ring cavity structure. At the FP resonant wavelengths, the described phenomenon gives rise to split modes with a nearly-transparent peak and a peak whose transmission is exceptionally sensitive to the intracavity loss. For small losses, the effective interaction pathlength of these modes is proportional respectively to the ratio and the product of the individual finesse coefficients of the two resonators. The results presented extend the conventional definition of resonant absorption and point to a way of circumventing the technological limitations of ultrahigh-quality resonators in spectroscopy and optical sensing schemes.