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Sample records for high-precision resonant cavity

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

    PubMed Central

    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. PMID:28117394

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Reliable and integrated technique for determining resonant frequency in radio frequency resonators. Application to a high-precision resonant cavity-based displacement sensor.

    PubMed

    Jauregui, Rigoberto; Asua, Estibaliz; Portilla, Joaquin; Etxebarria, Victor

    2015-03-01

    This paper presents a reliable and integrated technique for determining the resonant frequency of radio frequency resonators, which can be of interest for different purposes. The approach uses a heterodyne scheme as phase detector coupled to a voltage-controlled oscillator. The system seeks the oscillator frequency that produces a phase null in the resonator, which corresponds to the resonant frequency. A complete explanation of the technique to determine the resonant frequency is presented and experimentally tested. The method has been applied to a high-precision displacement sensor based on resonant cavity, obtaining a theoretical nanometric precision.

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

    SciTech Connect

    Barov, N.; Kim, J.S.; Weidemann, A.W.; 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.

  5. High Precision SC Cavity Diagnostics with HOM Measurements

    SciTech Connect

    Frisch, Josef; Hendrickson, Linda; McCormick, Douglas; May, Justin; Molloy, Stephen; Ross, Marc; /SLAC

    2006-08-18

    Experiments at the FLASH linac at DESY have demonstrated that the Higher Order Modes induced in Superconducting Cavities can be used to provide a variety of beam and cavity diagnostics. The centers of the cavities can be determined from the beam orbit which produces minimum power in the dipole HOM modes. The phase and amplitude of the dipole modes can be used as a high resolution beam position monitor, and the phase of the monopole modes to measure the beam phase relative to the accelerator RF. Beam orbit feedback which minimizes the dipole HOM power in a set of structures has been demonstrated. For most SC accelerators, the existing HOM couplers provide the necessary signals, and the down mix and digitizing electronics are straightforward, similar to those for a conventional BPM.

  6. RESONANT CAVITY EXCITATION SYSTEM

    DOEpatents

    Baker, W.R.

    1959-08-01

    A cavity excitation circuit is described for rapidly building up and maintaining high-level oscillations in a resonant cavity. The circuit overcomes oscillation buildup slowing effects such as ion locking in the cavity by providing for the selective application of an amplified accelerating drive signal to the main cavity exciting oscillator during oscillation buildup and a direct drive signal to the oscillator thereafter.

  7. RESONANT CAVITY EXCITATION SYSTEM

    DOEpatents

    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.

  8. Coupled resonator vertical cavity laser

    SciTech Connect

    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.

  9. Ring resonant cavities for spectroscopy

    DOEpatents

    Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.; Xie, Jinchun

    1999-01-01

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS).

  10. Ring resonant cavities for spectroscopy

    DOEpatents

    Zare, R.N.; Martin, J.; Paldus, B.A.; Xie, J.

    1999-06-15

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS). 6 figs.

  11. Geometry-invariant resonant cavities

    NASA Astrophysics Data System (ADS)

    Liberal, I.; Mahmoud, A. M.; Engheta, N.

    2016-03-01

    Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modelling to everyday life devices. The eigenfrequencies of conventional cavities are a function of their geometry, and, thus, the size and shape of a resonant cavity is selected to operate at a specific frequency. Here we demonstrate theoretically the existence of geometry-invariant resonant cavities, that is, resonators whose eigenfrequencies are invariant with respect to geometrical deformations of their external boundaries. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, such as epsilon-near-zero media, which enable decoupling of the temporal and spatial field variations in the lossless limit. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices.

  12. Geometry-invariant resonant cavities

    PubMed Central

    Liberal, I.; Mahmoud, A. M.; Engheta, N.

    2016-01-01

    Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modelling to everyday life devices. The eigenfrequencies of conventional cavities are a function of their geometry, and, thus, the size and shape of a resonant cavity is selected to operate at a specific frequency. Here we demonstrate theoretically the existence of geometry-invariant resonant cavities, that is, resonators whose eigenfrequencies are invariant with respect to geometrical deformations of their external boundaries. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, such as epsilon-near-zero media, which enable decoupling of the temporal and spatial field variations in the lossless limit. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices. PMID:27010103

  13. High Precision Continuous and Real-Time Measurement of Atmospheric Oxygen Using Cavity Ring-Down Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kim-Hak, David; Leuenberger, Markus; Berhanu, Tesfaye; Nyfeler, Peter; Hoffnagle, John; Sun, Minghua

    2017-04-01

    Oxygen (O2) is a major and vital component of the Earth atmosphere representing about 21% of its composition. It is consumed or produced through biochemical processes such as combustion, respiration, and photosynthesis and can be used as a top-down constraint on the carbon cycle. The observed variations of oxygen in the atmosphere are relatively small, in the order of a few ppm's. This presents the main technical challenge for the measurement since a very high level of precision on a large background is required. Only few analytical methods including mass spectrometry, fuel, ultraviolet[1] and paramagnetic cells are capable of achieving it. Here we present new developments of a high-precision gas analyzer that utilizes the technique of Cavity Ring-Down Spectroscopy to measure oxygen concentration and its oxygen isotope ratio 18O/16O. Its compact and ruggedness design combined with high precision and long-term stability allows the user to deploy the instrument in the field for continuous monitoring of atmospheric oxygen level. Measurements have a 1-σ 5-minute averaging precision of 1-2 ppm for O2 over a dynamic range of 0-50%. We will present comparative test results of this instrument against the incumbent technologies such as the mass spectrometer and the paramagnetic cell. In addition, we will demonstrate its long-term stability from a field deployment in Switzerland.

  14. High Precision Continuous and Real-Time Measurement of Atmospheric Oxygen Using Cavity Ring-Down Spectroscopy.

    NASA Astrophysics Data System (ADS)

    Kim-Hak, D.; Hoffnagle, J.; Rella, C.; Sun, M.

    2016-12-01

    Oxygen is a major and vital component of the Earth atmosphere representing about 21% of its composition. It is consumed or produced through biochemical processes such as combustion, respiration, and photosynthesis. Although atmospheric oxygen is not a greenhouse gas, it can be used as a top-down constraint on the carbon cycle. The variation observations of oxygen in the atmosphere are very small, in the order of the few ppm's. This presents the main technical challenge for measurement as a very high level of precision is required and only few methods including mass spectrometry, fuel cell, and paramagnetic are capable of overcoming it. Here we present new developments of a high-precision gas analyzer that utilizes the technique of Cavity Ring-Down Spectroscopy to measure oxygen concentration and oxygen isotope. Its compact and ruggedness design combined with high precision and long-term stability allows the user to deploy the instrument in the field for continuous monitoring of atmospheric oxygen level. Measurements have a 1-σ 5-minute averaging precision of 1-2 ppm for O2 over a dynamic range of 0-20%. We will present supplemental data acquired from our 10m tower measurements in Santa Clara, CA.

  15. High precision measurements of 16O12C17O using a new type of cavity ring down spectrometer

    NASA Astrophysics Data System (ADS)

    Daëron, M.; Stoltmann, T.; Kassi, S.; Burkhart, J.; Kerstel, E.

    2016-12-01

    Laser absorption techniques for the measurement of isotopologue abundances in gases have been dripping into the geoscientific community over the past decade. In the field of carbon dioxide such instruments have mostly been restricted to measurements of the most abundant stable isotopologues. Distinct advantages of CRDS techniques are non-destructiveness and the ability to resolve isobaric isotopologues. The determination of low-abundance isotopologues is predominantly limited by the linewidth of the probing laser, laser jitter, laser drift and system stability. Here we present first measurements of 16O12C17O abundances using a new type of ultra-precise cavity ring down spectrometer. By the use of Optical Feedback Frequency Stabilization, we achieved a laser line width in the sub-kHz regime with a frequency drift of less than 20 Hz/s. A tight coupling with an ultra-stable ring down cavity combined with a frequency tuning mechanism which enables us to arbitrarily position spectral points (Burkart et al., 2013) allowed us to demonstrate a single-scan (2 minutes) precision of 40 ppm on the determination of the 16O12C17O abundance. These promising results imply that routine, direct, high-precision measurements of 17O-anomalies in CO2 using this non-destructive method are in reach. References:Burkart J, Romanini D, Kassi S; Optical feedback stabilized laser tuned by single-sideband modulation; Optical Letters 12:2062-2063 (2013)

  16. Composite resonator vertical cavity laser diode

    SciTech Connect

    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.

  17. Seismic resonances of acoustic cavities

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  18. Long-term imaging of cellular forces with high precision by elastic resonator interference stress microscopy.

    PubMed

    Kronenberg, Nils M; Liehm, Philipp; Steude, Anja; Knipper, Johanna A; Borger, Jessica G; Scarcelli, Giuliano; Franze, Kristian; Powis, Simon J; Gather, Malte C

    2017-07-01

    Cellular forces are crucial for many biological processes but current methods to image them have limitations with respect to data analysis, resolution and throughput. Here, we present a robust approach to measure mechanical cell-substrate interactions in diverse biological systems by interferometrically detecting deformations of an elastic micro-cavity. Elastic resonator interference stress microscopy (ERISM) yields stress maps with exceptional precision and large dynamic range (2 nm displacement resolution over a >1 μm range, translating into 1 pN force sensitivity). This enables investigation of minute vertical stresses (<1 Pa) involved in podosome protrusion, protein-specific cell-substrate interaction and amoeboid migration through spatial confinement in real time. ERISM requires no zero-force reference and avoids phototoxic effects, which facilitates force monitoring over multiple days and at high frame rates and eliminates the need to detach cells after measurements. This allows observation of slow processes such as differentiation and further investigation of cells, for example, by immunostaining.

  19. High Precision 13C/12C Measurement of Dissolved Carbon Using a Transportable Cavity Ring-Down Spectrophotometer System

    NASA Astrophysics Data System (ADS)

    Saad, N.; Crosson, E.

    2009-05-01

    We report here on the measurement of high precision δ13C from total inorganic carbon (TIC) and dissolved organic carbon (DOC) using a sample preparation system coupled to a small footprint Wavelength- Scanned Cavity Ring-Down Spectrometer (WS-CRDS). This system is capable of applying a 5% H3PO4 solution or a sodium persulfate oxidation process to a water sample in an exetainer vial, thereby liberating gaseous CO2 and permitting stable carbon isotope measurement in TIC and DOC, respectively. The isotopic carbon signature determination can then be used to trace the origin of carbonates or organic carbon compounds. In a first phase, a manual process was employed in which TIC containing samples were acidified and the evolved CO2 was collected inside gas pillows. The gas pillows were then connected to the inlet of the isotopic WS-CRDS instrument for carbon ratio measurement. In a second phase, the CO2 liberation processes were automated in an integrated analyzer enabling software control of a sample preparation system directly connected to the gas inlet of the isotopic WS-CRDS instrument. A measurement precision of the isotopic ratio in the range of 0.2 to 0.4 permil was achieved in minutes of measurement time. Such precision readily distinguishes the isotopic TIC and DOC signatures from a set of three different stream water samples collected from various sites in Northern California. The current TIC/DOC- CRDS setup will enable shipboard measurement and presents a rugged, portable and inexpensive analytical instrumentation alternative to the traditional use of methods based on the more complex and lab-confined isotope ratio mass spectrometry technique.

  20. High precision micro-impulse measurements for micro-thrusters based on torsional pendulum and sympathetic resonance techniques.

    PubMed

    Zhang, Daixian; Wu, Jianjun; Zhang, Rui; Zhang, Hua; He, Zhen

    2013-12-01

    A sympathetic resonance theory is analyzed and applied in a newly developed torsional pendulum to measure the micro-impulse produced by a μN s-class ablative pulsed plasma thruster. According to theoretical analysis on the dynamical behaviors of a torsional pendulum, the resonance amplification effect of micro-signals is presented. In addition, a new micro-impulse measurement method based on sympathetic resonance theory is proposed as an improvement of the original single pulse measurement method. In contrast with the single pulse measurement method, the advantages of sympathetic resonance method are significant. First, because of the magnification of vibration signals due to resonance processes, measurement precision for the sympathetic resonance method becomes higher especially in reducing reading error. With an increase in peak number, the relative errors induced by readout of voltage signals decrease to approximately ±1.9% for the sympathetic resonance mode, whereas the relative error in single pulse mode is estimated as ±13.4%. Besides, by using the resonance amplification effect the sympathetic resonance method makes it possible to measure an extremely low-impulse beyond the resolution of a thrust stand without redesigning or purchasing a new one. Moreover, because of the simple operational principle and structure the sympathetic resonance method is much more convenient and inexpensive to be implemented than other high-precision methods. Finally, the sympathetic resonance measurement method can also be applied in other thrust stands to improve further the ability to measure the low-impulse bits.

  1. High precision micro-impulse measurements for micro-thrusters based on torsional pendulum and sympathetic resonance techniques

    NASA Astrophysics Data System (ADS)

    Zhang, Daixian; Wu, Jianjun; Zhang, Rui; Zhang, Hua; He, Zhen

    2013-12-01

    A sympathetic resonance theory is analyzed and applied in a newly developed torsional pendulum to measure the micro-impulse produced by a μN s-class ablative pulsed plasma thruster. According to theoretical analysis on the dynamical behaviors of a torsional pendulum, the resonance amplification effect of micro-signals is presented. In addition, a new micro-impulse measurement method based on sympathetic resonance theory is proposed as an improvement of the original single pulse measurement method. In contrast with the single pulse measurement method, the advantages of sympathetic resonance method are significant. First, because of the magnification of vibration signals due to resonance processes, measurement precision for the sympathetic resonance method becomes higher especially in reducing reading error. With an increase in peak number, the relative errors induced by readout of voltage signals decrease to approximately ±1.9% for the sympathetic resonance mode, whereas the relative error in single pulse mode is estimated as ±13.4%. Besides, by using the resonance amplification effect the sympathetic resonance method makes it possible to measure an extremely low-impulse beyond the resolution of a thrust stand without redesigning or purchasing a new one. Moreover, because of the simple operational principle and structure the sympathetic resonance method is much more convenient and inexpensive to be implemented than other high-precision methods. Finally, the sympathetic resonance measurement method can also be applied in other thrust stands to improve further the ability to measure the low-impulse bits.

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

    SciTech Connect

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

    2005-09-20

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

  3. Near field imaging with resonant cavity lens.

    PubMed

    Li, Guixin; Li, Jensen; Tam, H L; Chan, C T; Cheah, K W

    2010-02-01

    We showed that a Ag-SiO(2)-Ag Fabry-Pérot cavity can be used in near-field imaging based on omnidirectional resonance tunneling. The omnidirectional resonance was experimentally demonstrated in the Ag-SiO(2)-Ag resonant cavity working at a wavelength of 365 nm. The resonant cavity lens with high transmittance and high image fidelity was fabricated using standard photolithography method. Grating source with 190 nm line resolution was imaged through the resonant cavity lens with a total thickness of 128 nm.

  4. Cavity- and waveguide-resonators in electron paramagnetic resonance, nuclear magnetic resonance, and magnetic resonance imaging.

    PubMed

    Webb, Andrew

    2014-11-01

    Cavity resonators are widely used in electron paramagnetic resonance, very high field magnetic resonance microimaging and also in high field human imaging. The basic principles and designs of different forms of cavity resonators including rectangular, cylindrical, re-entrant, cavity magnetrons, toroidal cavities and dielectric resonators are reviewed. Applications in EPR and MRI are summarized, and finally the topic of traveling wave MRI using the magnet bore as a waveguide is discussed.

  5. High-Precision Calibration of Electron Beam Energy from the Hefei Light Source Using Spin Resonant Depolarization

    NASA Astrophysics Data System (ADS)

    Lan, Jie-Qin; Xu, Hong-Liang

    2014-12-01

    The electron beam energy at the Hefei Light Source (HLS) in the National Synchrotron Radiation Laboratory is highly precisely calibrated by using the method of spin resonant depolarization for the first time. The spin tune and the beam energy are determined by sweeping the frequency of a radial rf stripline oscillating magnetic field to artificially excite a spin resonance and depolarize the beam. The resonance signal is recognized by observing the sudden change of the Touschek loss counting rate of the beam. The possible systematic errors of the experiment are presented and the accuracy of the calibrated energy is shown to be about 10-4. A series of measurements show that the energy stability of the machine is of the order of 9 × 10-3.

  6. The Heliosphere as Resonant Cavity

    NASA Technical Reports Server (NTRS)

    Bames, Aaron

    1999-01-01

    If a disturbance in the supersonic solar wind reaches the heliospheric shock, a number of events ensue. First, the shock itself responds with inward or outward motion. Secondly, the disturbance propagates outward through the heliosheath as a sound or magnetoacoustic wave; eventually it reaches the heliopause and is (partially) reflected back toward the termination shock. The reflected wave can return to the shock, affecting the shock's motion, and be reflected yet again. The repetition of these processes can produce a 'ringing' in the heliosheath. This suggests that it may be useful to regard the heliosheath as a resonant acoustic cavity with inner and outer boundaries at the termination shock and heliopause, respectively. To evaluate this concept we have developed a simple model of small-amplitude resonant oscillations in an outwardly flowing gas, with appropriate boundary conditions (shock on the interior, tangential discontinuity on the exterior boundary). The fundamental mode of oscillation has a period of order T approx. 2D/C, where C is the speed of sound in the heliosheath and D is the distance between the two boundaries. Typical numerical models of the heliosphere give C approx. 200-500 km/s and D approx. 20 - 100 AU, giving T approx. 0.5 - 2.5 years. Hence we suggest that motions of the heliosheath and termination shock will occur with time scales of the order of a year, and are the consequence of the resonant nature of the heliospheric cavity rather than the history of variation at the Sun and/or in the solar wind. In particular, we suggest that the motion of the termination shock may be unrelated to solar variations over the time scale of the sunspot cycle.

  7. Very-high-precision bound-state spectroscopy near a {sup 85}Rb Feshbach resonance

    SciTech Connect

    Claussen, N.R.; Kokkelmans, S.J.J.M.F.; Thompson, S.T.; Donley, E.A.; Hodby, E.; Wieman, C.E.

    2003-06-01

    We precisely measured the binding energy ({epsilon}{sub bind}) of a molecular state near the Feshbach resonance in a {sup 85}Rb Bose-Einstein condensate (BEC). Rapid magnetic-field pulses induced coherent atom-molecule oscillations in the BEC. We measured the oscillation frequency as a function of B field and fit the data to a coupled-channel model. Our analysis constrained the Feshbach resonance position [155.041(18) G], width [10.71(2) G], and background scattering length [-443(3)a{sub 0}] and yielded new values for the Rb interaction parameters. These results improved our estimate for the stability condition of an attractive BEC. We also found evidence for a mean-field shift to {epsilon}{sub bind}.

  8. High precision particle mass sensing using microchannel resonators in the second vibration mode

    SciTech Connect

    Lee, Jungchul; Bryan, Andrea K.; Manalis, Scott R.

    2011-02-15

    An intrinsic uncertainty in particle mass sensing with the suspended microchannel resonator results from variation in a particle's position near the free end of the resonator. To circumvent this error we employ the second flexural bending mode. This mode exhibits additional frequency peaks while particles pass over the antinode, a point where the frequency shift is insensitive to the lateral position of the particle. We measure polystyrene beads with the first and second modes and confirm that the second mode sensing provides a narrower mass histogram. For 3 {mu}m diameter beads, second mode sensing at the antinode improves the coefficient of variation in buoyant mass from 1.76% to 1.05% for population measurements and from 1.40% to 0.53% for a single trapped particle.

  9. Combat Hardened Communications: High Precision Frequency Control Using Resonators Immune to Acceleration and Stress Fields,

    DTIC Science & Technology

    1980-06-01

    cancel. Compensation of thermal transients cores about by Ci2 use of a special, doubly rotated orientation of cut . We show that all ........... .. ... 1...laboratory standard of conventional design, using an AT cut crystal, and protected to the greatest possible extent from environmental disturbances. Its...frequency control element commonly used is the AT cut quartz resonator, a singly rotated plate, shown in Figure 3, with 01,+350. Its traditional

  10. High-precision metrology of highly charged ions via relativistic resonance fluorescence.

    PubMed

    Postavaru, O; Harman, Z; Keitel, C H

    2011-01-21

    Resonance fluorescence of laser-driven highly charged ions is investigated with regard to precisely measuring atomic properties. For this purpose an ab initio approach based on the Dirac equation is employed that allows for studying relativistic ions. These systems provide a sensitive means to test correlated relativistic dynamics, quantum electrodynamic phenomena and nuclear effects by applying x-ray lasers. We show how the narrowing of sidebands in the x-ray fluorescence spectrum by interference due to an additional optical driving can be exploited to determine atomic dipole or multipole moments to unprecedented accuracy.

  11. Resonant-cavity antenna for plasma heating

    DOEpatents

    Perkins, Jr., Francis W.; Chiu, Shiu-Chu; Parks, Paul; Rawls, John M.

    1987-01-01

    Disclosed is a resonant coil cavity wave launcher for energizing a plasma immersed in a magnetic field. Energization includes launching fast Alfven waves to excite ion cyclotron frequency resonances in the plasma. The cavity includes inductive and capacitive reactive members spaced no further than one-quarter wavelength from a first wall confinement chamber of the plasma. The cavity wave launcher is energized by connection to a waveguide or transmission line carrying forward power from a remote radio frequency energy source.

  12. High precision modeling for fundamental physics experiments

    NASA Astrophysics Data System (ADS)

    Rievers, Benny; Nesemann, Leo; Costea, Adrian; Andres, Michael; Stephan, Ernst P.; Laemmerzahl, Claus

    With growing experimental accuracies and high precision requirements for fundamental physics space missions the needs for accurate numerical modeling techniques are increasing. Motivated by the challenge of length stability in cavities and optical resonators we propose the develop-ment of a high precision modeling tool for the simulation of thermomechanical effects up to a numerical precision of 10-20 . Exemplary calculations for simplified test cases demonstrate the general feasibility of high precision calculations and point out the high complexity of the task. A tool for high precision analysis of complex geometries will have to use new data types, advanced FE solver routines and implement new methods for the evaluation of numerical precision.

  13. Surface-Enhanced Resonance Raman Scattering Nanostars for High Precision Cancer Imaging

    PubMed Central

    Harmsen, Stefan; Huang, Ruimin; Wall, Matthew A.; Karabeber, Hazem; Samii, Jason M.; Spaliviero, Massimiliano; White, Julie R.; Monette, Sébastien; O’Connor, Rachael; Pitter, Kenneth L.; Sastra, Stephen A.; Saborowski, Michael; Holland, Eric C.; Singer, Samuel; Olive, Kenneth P.; Lowe, Scott W.; Blasberg, Ronald G.; Kircher, Moritz F.

    2015-01-01

    The inability to visualize the true extent of cancers represents a significant challenge in many areas of oncology. The margins of most cancer types are not well demarcated because the cancer diffusely infiltrates the surrounding tissues. Furthermore, cancers may be multifocal and characterized by the presence of microscopic satellite lesions. Such microscopic foci represent a major reason for persistence of cancer, local recurrences, and metastatic spread and are usually impossible to visualize with currently available imaging technologies. An imaging method to reveal the tumor extent is desired clinically and surgically. Here we show the precise visualization of tumor margins, microscopic tumor invasion, and multifocal loco-regional tumor spread using a new generation of surface-enhanced resonance Raman scattering (SERRS) nanoparticles, which are termed here SERRS-nanostars. The SERRS-nanostars feature a star-shaped gold core, a Raman reporter resonant in the near-infrared spectrum, and a primer-free silication method. In mouse models of pancreatic cancer, breast cancer, prostate cancer, and sarcoma, SERRS-nanostars enabled accurate detection of macroscopic malignant lesions as well as microscopic disease, without the need for a targeting moiety. Moreover, the sensitivity (1.5 femtomolar limit of detection under in vivo Raman imaging conditions) of SERRS-nanostars allowed imaging of premalignant lesions of pancreatic and prostatic neoplasias. High sensitivity and broad applicability, in conjunction with their inert gold-silica composition, render SERRS-nanostars a promising imaging agent for more precise cancer imaging and resection. PMID:25609167

  14. Resonant-cavity antenna for plasma heating

    SciTech Connect

    Perkins, F.W. Jr.; Chiu, S.C.; Rawls, J.M.

    1987-04-28

    This patent describes a magnetic confinement plasma device having a plasma. The plasma is immersed in a strong magnetic field and confined within an evacuated plasma chamber. A wave launcher for launching electromagnetic waves in the range of frequencies of 10 MHz to 200 MHz energizes and thereby heats the plasma. The wave launcher is spaced-apart from the plasma. The wave launcher comprises: a resonant cavity, including resonant chamber walls for containing electromagnetic fields; connection means connecting the resonant cavity to a transmission line carrying electromagnetic wave energy to the resonant cavity; at least one capacitive reactive element, and at least one inductive reactive element disposed within the resonant cavity; the capacitive reactive member separated from the chamber walls of the resonant cavity by a first predefined gap, with the capacitive reactive member and the chamber walls of the resonant cavity oriented approximately tangential to the strong magnetic field; the capacitive and the inductive reactive elements spaced apart from the plasma a second predetermined distance which at least partially determines the frequency of the launched waves; and the resonant cavity cooperating with the capacitive and the inductive reactive elements so as to launch electromagnetic waves in the range of frequencies, toward the plasma.

  15. Coupled Resonator Vertical Cavity Laser Diode

    SciTech Connect

    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.

  16. Control of Cavity Resonance Using Oscillatory Blowing

    NASA Technical Reports Server (NTRS)

    Scarfe, Alison Lamp; Chokani, Ndaona

    2000-01-01

    The near-zero net mass oscillatory blowing control of a subsonic cavity flow has been experimentally investigated. An actuator was designed and fabricated to provide both steady and oscillatory blowing over a range of blowing amplitudes and forcing frequencies. The blowing was applied just upstream of the cavity front Wall through interchangeable plate configurations These configurations enabled the effects of hole size, hole shape, and blowing angle to be examined. A significant finding is that in terms of the blowing amplitude, the near zero net mass oscillatory blowing is much more effective than steady blowing; momentum coefficients Lip two orders of magnitude smaller than those required for steady blowing are sufficient to accomplish the same control of cavity resonance. The detailed measurements obtained in the experiment include fluctuating pressure data within the cavity wall, and hot-wire measurements of the cavity shear layer. Spectral and wavelet analysis techniques are applied to understand the dynamics and mechanisms of the cavity flow with control. The oscillatory blowing, is effective in enhancing the mixing in the cavity shear layer and thus modifying the feedback loop associated with the cavity resonance. The nonlinear interactions in the cavity flow are no longer driven by the resonant cavity modes but by the forcing associated with the oscillatory blowing. The oscillatory blowing does not suppress the mode switching behavior of the cavity flow, but the amplitude modulation is reduced.

  17. Cavities for electron spin resonance: predicting the resonant frequency

    NASA Astrophysics Data System (ADS)

    Colton, John; Miller, Kyle; Meehan, Michael; Spencer, Ross

    Microwave cavities are used in electron spin resonance to enhance magnetic fields. Dielectric resonators (DRs), pieces of high dielectric material, can be used to tailor the resonant frequency of a cavity. However, designing cavities with DRs to obtain desired frequencies is challenging and in general can only be done numerically with expensive software packages. We present a new method for calculating the resonant frequencies and corresponding field modes for cylindrically symmetric cavities and apply it to a cavity with vertically stacked DRs. The modes of an arbitrary cavity are expressed as an expansion of empty cavity modes. The wave equation for D gives rise to an eigenvalue equation whose eigenvalues are the resonant frequencies and whose eigenvectors yield the electric and magnetic fields of the mode. A test against theory for an infinitely long dielectric cylinder inside an infinite cavity yields an accuracy better than 0.4% for nearly all modes. Calculated resonant frequencies are also compared against experiment for quasi-TE011 modes in resonant cavities with ten different configurations of DRs; experimental results agree with predicted values with an accuracy better than 1.0%. MATLAB code is provided at http://www.physics.byu.edu/research/coltonlab/cavityresonance.

  18. Folded cavity design for a ruby resonator

    NASA Technical Reports Server (NTRS)

    Arunkumar, K. A.; Trolinger, James D.

    1988-01-01

    A folded cavity laser resonator operating in the TEM(00) mode has been built and tested. The new oscillator configuration leads to an increase in efficiency and to better line narrowing due to the increased number of passes through the laser rod and tuning elements, respectively. The modification is shown to lead to cavity ruggedization.

  19. Hyperbolic resonances of metasurface cavities.

    PubMed

    Keene, D; Durach, M

    2015-07-13

    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.

  20. Parametric resonance in tunable superconducting cavities

    NASA Astrophysics Data System (ADS)

    Wustmann, Waltraut; Shumeiko, Vitaly

    2013-05-01

    We develop a theory of parametric resonance in tunable superconducting cavities. The nonlinearity introduced by the superconducting quantum interference device (SQUID) attached to the cavity and damping due to connection of the cavity to a transmission line are taken into consideration. We study in detail the nonlinear classical dynamics of the cavity field below and above the parametric threshold for the degenerate parametric resonance, featuring regimes of multistability and parametric radiation. We investigate the phase-sensitive amplification of external signals on resonance, as well as amplification of detuned signals, and relate the amplifier performance to that of linear parametric amplifiers. We also discuss applications of the device for dispersive qubit readout. Beyond the classical response of the cavity, we investigate small quantum fluctuations around the amplified classical signals. We evaluate the noise power spectrum both for the internal field in the cavity and the output field. Other quantum-statistical properties of the noise are addressed such as squeezing spectra, second-order coherence, and two-mode entanglement.

  1. Continuous Flow - Cavity RingDown Spectroscopy Using a Novel Universal Interface for High-Precision Bulk 13C Analysis

    NASA Astrophysics Data System (ADS)

    Saad, Nabil; Richman, Bruce

    2010-05-01

    We have developed the world's first optical spectroscopy-based system for bulk stable isotope analysis of 13C. The system is based on a novel universal interface, named LIAISON, capable of coupling to almost any CO2-generating sample preparation front-end ranging from an elemental analyzer to any dissolved carbon analysis module, which are of significant use in geochemical, ecological and food authentication studies. In one specific application, we have coupled LIAISON to an elemental analyzer (EA) and to a cavity ring-down spectrometer (CRDS) for 13C isotopic analysis of adulterated honey samples. Another application was developed to analyze dissolved inorganic carbon in water samples. LIAISON is suited for handling a high-throughput sample analysis process by running three different gas handling operations in parallel: Admitting combustion gas from the EA into a first gas bellows, analyzing the previous sample collected into a second gas bellows with CRDS, and flushing and purging a third gas bellows in preparation for the upcoming sample collection operation. The sample-to-sample analysis time is 10 minutes and the operation is completely automated for the whole front-end auto-sampler tray capacity, requiring no operator intervention. The CRDS data are collected, tabulated and saved into an output text file. The memory effect between the USGS L-Glutamic acid standard at natural abundance and the moderately enriched USGS L-Glutamic acid standard is excluded by the selection of the adequate number and duration of flush and purge cycles of the gas sample bags. The system's proven accuracy was cross-checked with EA-IRMS and its achieved precision was typically less than 0.2 permil, including the 13C-enriched tested samples. The LIAISON-CRDS system presented here provides a fully automated solution for 13C bulk stable isotope analysis with unprecedented ease-of-use and possible field portability and application with the availability of a compact front-end. In

  2. Cavity resonator coil for high field magnetic resonance imaging.

    PubMed

    Solis, S E; Tomasi, D; Rodriguez, A O

    2007-01-01

    A variant coil of the high frequency cavity resonator coil was experimentally developed according to the theoretical frame proposed by Mansfield in 1990. This coil design is similar to the popular birdcage coil but it has the advantage that it can be easily built following the physical principles of the cavity resonators [1]. The equivalent circuit approach was used to compute the resonant frequency of this coil design, and compared the results with those frequency values obtained with theory. A transceiver coil composed of 4 cavities with a rod length of 4.5 cm, and a resonant frequency of 170.29 MHz was built. Phantom images were then acquired to test its viability using standard imaging sequences. The theory facilitates its development for high frequency MRI applications of animal models.

  3. Plasmon resonant cavities in vertical nanowire arrays

    SciTech Connect

    Bora, M; Bond, T; Behymer, E; Chang, A

    2010-02-23

    We investigate tunable plasmon resonant cavity arrays in paired parallel nanowire waveguides. Resonances are observed when the waveguide length is an odd multiple of quarter plasmon wavelengths, consistent with boundary conditions of node and antinode at the ends. Two nanowire waveguides satisfy the dispersion relation of a planar metal-dielectric-metal waveguide of equivalent width equal to the square field average weighted gap. Confinement factors over 103 are possible due to plasmon focusing in the inter-wire space.

  4. Optical Resonant Cavity in a Nanotaper

    SciTech Connect

    Lee, Sang Hyun; Goto, Takenari; Miyazaki, Hiroshi; Chang, Jiho; Yao, Takafumi

    2010-01-01

    The present study describes an optical resonant cavity in a nanotaper with scale reduction from micro to several nanometers. Both experimental results and a finite-difference time-domain (FDTD)-based simulation suggested that the nanometer-scale taper with a diameter similar to the wavelength of light acted as a mirror, which facilitated the formation of a laser cavity and caused lasing in ZnO nanotapers. As the light inside the nanotaper propagated toward the apex, the lateral mode was reduced and reflection occurred. This report suggests that use of the resonant optical cavities in nanotapers might result in novel active and passive optical components, which will broaden the horizons of photonic technology.

  5. Deflecting light into resonant cavities for spectroscopy

    DOEpatents

    Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.

    1998-01-01

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available.

  6. Feedback instability of the ionospheric resonant cavity

    NASA Technical Reports Server (NTRS)

    Lysak, Robert L.

    1991-01-01

    A model is developed that provides a theoretical basis for previous numerical results showing a feedback instability with frequencies characteristic of Alfven travel times within the region of the large increase of Alfven speed above the ionosphere. These results have been extended to arbitrary ionospheric conductivity by developing a numerical solution of the cavity dispersion relation that involves Bessel functions of complex order and argument. It is concluded that the large contrast between the magnetospheric and ionospheric Alfven speed leads to the formation of resonant cavity modes with frequencies ranging from 0.1 to 1 Hz. The presence of the cavity leads to a modification of the reflection characteristics of Alfven waves with frequencies that compare to the cavity's normal modes.

  7. Deflecting light into resonant cavities for spectroscopy

    DOEpatents

    Zare, R.N.; Martin, J.; Paldus, B.A.

    1998-09-29

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available. 5 figs.

  8. Optical cavity resonator in an expanding universe

    NASA Astrophysics Data System (ADS)

    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

  9. Plasmon resonant cavities in vertical nanowire arrays

    DOEpatents

    Bora, Mihail; Bond, Tiziana C.; Fasenfest, Benjamin J.; Behymer, Elaine M.

    2014-07-15

    Tunable plasmon resonant cavity arrays in paired parallel nanowire waveguides are presented. Resonances can be observed when the waveguide length is an odd multiple of quarter plasmon wavelengths, consistent with boundary conditions of node and antinode at the ends. Two nanowire waveguides can satisfy the dispersion relation of a planar metal-dielectric-metal waveguide of equivalent width equal to the square field average weighted gap. Confinement factors of over 10.sup.3 are possible due to plasmon focusing in the inter-wire space.

  10. Resonant cavity enhanced multi-analyte sensing

    NASA Astrophysics Data System (ADS)

    Bergstein, David Alan

    Biological research and medicine increasingly depend on interrogating binding interactions among small segments of DNA, RNA, protein, and bio-specific small molecules. Microarray technology, which senses the affinity for target molecules in solution for a multiplicity of capturing agents fixed to a surface, has been used in biological research for gene expression profiling and in medicine for molecular biomarker detection. Label-free affinity sensing is preferable as it avoids fluorescent labeling of the target molecules, reducing test cost and variability. The Resonant Cavity Imaging Biosensor (RCIB) is a label-free optical inference based technique introduced that scales readily to high throughput and employs an optical resonant cavity to enhance sensitivity by a factor of 100 or more. Near-infrared light centered at 1512.5 nm couples resonantly through a cavity constructed from Si/SiO2 Bragg reflectors, one of which serves as the binding surface. As the wavelength is swept 5 nm, an Indium-Gallium-Arsenide digital camera monitors cavity transmittance at each pixel with resolution 128 x 128. A wavelength shift in the local resonant response of the optical cavity indicates binding. Positioning the sensing surface with respect to the standing wave pattern of the electric field within the cavity, one can control the sensitivity of the measurement to the presence of bound molecules thereby enhancing or suppressing sensitivity where appropriate. Transmitted intensity at thousands of pixel locations are recorded simultaneously in a 10 s, 5 nm scan. An initial proof-of-principle setup was constructed. A sample was fabricated with 25, 100 mum wide square regions, each with a different density of 1 mum square depressions etched 12 nm into the S1O 2 surface. The average depth of each etched region was found with 0.05 nm RMS precision when the sample remains loaded in the setup and 0.3 nm RMS precision when the sample is removed and replaced. Selective binding of the protein

  11. Semiconductor single crystal external ring resonator cavity laser and gyroscope

    SciTech Connect

    Spitzer, M.P.

    1993-08-31

    A ring laser is described comprising: a semiconductor single crystal external ring resonator cavity having a plurality of reflecting surfaces defined by the planes of the crystal and establishing a closed optical path; and a discrete laser medium disposed in said semiconductor single crystal external ring resonator cavity for generating coherent light in said cavity, wherein said resonator cavity is decoupled from the laser medium.

  12. Tunable cavity resonator including a plurality of MEMS beams

    DOEpatents

    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.

  13. Theory of RF superconductivity for resonant cavities

    NASA Astrophysics Data System (ADS)

    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.

  14. Ferrite-filled cavities for compact planar resonators

    NASA Astrophysics Data System (ADS)

    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.

  15. Flow-induced resonance of screen-covered cavities

    NASA Technical Reports Server (NTRS)

    Soderman, Paul T.

    1990-01-01

    An experimental study of screen-covered cavities exposed to airflow tangent to the screen is described. The term screen refers to a thin metal plate perforated with a repetitive pattern of round holes. The purpose was to find the detailed aerodynamic and acoustic mechanisms responsible for screen-covered cavity resonance and to find ways to control the pressure oscillations. Results indicate that strong cavity acoustic resonances are created by screen orifices that shed vortices which couple resonance by choosing hole spacings such that shed vortices do not arrive at a downstream orifice in synchronization with cavity pressure oscillations. The proper hole pattern is effective at all airspeeds. It was also discovered that a reduction of orifice size tended to weaken the screen/cavity interaction regardless of hole pattern, probably because of viscous flow losses at the orifices. The screened cavities that resonated did so at much higher frequencies than the equivalent open cavity. The classical large eddy phenomenon occurs at the relatively small scale of the orifices (the excitation is typically of high frequency). The wind tunnel study was made at airspeeds from 0 to 100m/sec. The 457-mm-long by 1.09-m-high rectangular cavities had length-to-depth ratios greater than one, which is indicative of shallow cavities. The cavity screens were perforated in straight rows and columns with hole diameters ranging from 1.59 to 6.35 mm and with porosities from 2.6 to 19.6 percent.

  16. Dynamic Color Displays Using Stepwise Cavity Resonators.

    PubMed

    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.

  17. Characteristic impedances in output cylindrical coaxial cavity resonator of klystron

    SciTech Connect

    Dong, Yuhe; Xie, Xingjuan; Huang, Chuanlu

    2011-07-01

    Cylindrical coaxial cavity resonator with shift-tubes coupled with rectangular waveguide is designed. The gap characteristic impedance and external quality factor of higher order transverse magnetic mode TM{sub 310} in the cavity are simulated with high frequency electromagnetic simulator ISFEL-3D. The ununiformity of the characteristic impedance resulted from the coupling aperture is reduced through introduction of concave delves on peripheral wall of the cavity. (author)

  18. Efficiency enhancement of coupled-cavity TWT's through cavity resonance tapering

    NASA Technical Reports Server (NTRS)

    Connolly, D. J.

    1979-01-01

    The paper examines efficiency enhancement of coupled-cavity traveling-wave tube (TWT) through cavity resonance tapering. Beam-wave resynchronization through circuit velocity reduction is used for TWT efficiency enhancement, with circuit velocity reduction in coupled cavity TWT's accomplished through period tapering. However, the amount of the latter is limited by the stability considerations, so that beyond a critical value of velocity reduction, the tube may be subject to zero drive oscillations originating in the velocity taper region. The coupled-cavity resonance tapering allows the velocity reduction to continue beyond the limit of stable period tapering, and it is accomplished by a gradual reduction in the cavity resonance frequency, with the period and the circuit bandwidth unchanged. The advantages of cavity resonance tapering vs period tapering are discussed, and test data are presented with the results of large-signal computer calculations. It is shown that cavity resonance tapering can produce efficiencies as period tapering without incurring the same risk of lower band-edge oscillations.

  19. Development of cell-based quantitative evaluation method for cell cycle-arrest type cancer drugs for apoptosis by high precision surface plasmon resonance sensor

    NASA Astrophysics Data System (ADS)

    Ona, Toshihiro; Nishijima, Hiroshi; Kosaihira, Atsushi; Shibata, Junko

    2008-04-01

    In vitro rapid and quantitative cell-based assay is demanded to verify the efficacy prediction of cancer drugs since a cancer patient may have unconventional aspects of tumor development. Here, we show the rapid and non-label quantitative verifying method and instrumentation of apoptosis for cell cycle-arrest type cancer drugs (Roscovitine and D-allose) by reaction analysis of living liver cancer cells cultured on a sensor chip with a newly developed high precision (50 ndeg s -1 average fluctuation) surface plasmon resonance (SPR) sensor. The time-course cell reaction as the SPR angle change rate for 10 min from 30 min cell culture with a drug was significantly related to cell viability. By the simultaneous detection of differential SPR angle change and fluorescence by specific probes using the new instrument, the SPR angle was related to the nano-order potential decrease in inner mitochondrial membrane potential. The results obtained are universally valid for the cell cycle-arrest type cancer drugs, which mediate apoptosis through different cell-signaling pathways, by a liver cancer cell line of Hep G2 (P<0.001). This system towards the application to evaluate personal therapeutic potentials of drugs using cancer cells from patients in clinical use.

  20. Diode Laser Optically Injected by Resonance of a Monolithic Cavity

    NASA Astrophysics Data System (ADS)

    Peng, Yu; Zhao, Yang; Li, Ye; Yang, Tao; Cao, Jian-Ping; Fang, Zhan-Jun; Zang, Er-Jun

    2011-11-01

    We demonstrate a self-injection locking extended cavity diode laser (ECDL) using resonant optical feedback from the p-polarization of a monolithic folded Fabry—Perot parallel cavity (MFC). The full width at half maximum of the MFC resonance is 31 MHz. With the help of a narrow-linewidth reference laser, the linewidth of the ECDL is measured to be about 7 kHz. The frequency of the laser could be tuned at 160 MHz with an amplitude of 40 V by a PZT mounted on the monolithic cavity and the voltage tuning coefficient is about 4 MHz/V.

  1. Superharmonic resonances in a strongly coupled cavity-atom system

    NASA Astrophysics Data System (ADS)

    Buks, Eyal; Deng, Chunqing; Orgazzi, Jean-Luc F. X.; Otto, Martin; Lupascu, Adrian

    2016-09-01

    We study a system consisting of a superconducting flux qubit strongly coupled to a microwave cavity. The fundamental cavity mode is externally driven and the response is investigated in the weak nonlinear regime. We find that near the crossing point, at which the resonance frequencies of the cavity mode and qubit coincide, the sign of the Kerr coefficient changes, and consequently the type of nonlinear response changes from softening to hardening. Furthermore, the cavity response exhibits superharmonic resonances (SHR) when the ratio between the qubit frequency and the cavity fundamental mode frequency is tuned close to an integer value. The nonlinear response is characterized by the method of intermodulation and both signal and idler gains are measured. The experimental results are compared with theoretical predictions and good qualitative agreement is obtained. The SHRs have potential for applications in quantum amplification and generation of entangled states of light.

  2. Entanglement Generation Between Two Mechanical Resonators in Two Optomechanical Cavities

    NASA Astrophysics Data System (ADS)

    Rehaily, Adel AL; Bougouffa, Smail

    2017-05-01

    A standard model is suggested to explore correlation features of two spatially separated optomechanical cavities. The cavities are coupled through the photon-hopping process. In particular, we investigate the generation of entanglement between mechanical resonators in the strong coupling regime and the two cavities are assumed to be driven by a coherent laser field. In order to quantify entanglement we use the logarithmic negativity. The analytical solutions are presented for the system in a parameter regime very close to the current experimental results. We show that in the presence of the photon hopping process between the cavities, the two mechanical resonators and the field modes can be entangled. This shows clearly that the entanglement can be transfer via radiation pressure of a photon hopping coupling from the intracavity photon-phonon entanglements to an inter-cavity photon-photon or phonon-phonon entanglement.

  3. Resonance control in SRF cavities at FNAL

    SciTech Connect

    Schappert, W.; Pischalnikov, Y.; Scorrano, M.; /INFN, Pisa

    2011-03-01

    The Lorentz force can dynamically detune pulsed Superconducting RF cavities. Considerable additional RF power can be required to maintain the accelerating gradient if no effort is made to compensate for this detuning. Compensation systems using piezo actuators have been used successfully at DESY and elsewhere to control Lorentz Force Detuning (LFD). Recently, Fermilab has developed an adaptive compensation system for cavities in the Horizontal Test Stand, in the SRF Accelerator Test Facility, and for the proposed Project X.

  4. High-Q resonant cavities for terahertz quantum cascade lasers.

    PubMed

    Campa, A; Consolino, L; Ravaro, M; Mazzotti, D; Vitiello, M S; Bartalini, S; De Natale, P

    2015-02-09

    We report on the realization and characterization of two different designs for resonant THz cavities, based on wire-grid polarizers as input/output couplers, and injected by a continuous-wave quantum cascade laser (QCL) emitting at 2.55 THz. A comparison between the measured resonators parameters and the expected theoretical values is reported. With achieved quality factor Q ≈ 2.5 × 10(5), these cavities show resonant peaks as narrow as few MHz, comparable with the typical Doppler linewidth of THz molecular transitions and slightly broader than the free-running QCL emission spectrum. The effects of the optical feedback from one cavity to the QCL are examined by using the other cavity as a frequency reference.

  5. Reducing flow-induced resonance in a cavity

    NASA Technical Reports Server (NTRS)

    Cattafesta, III, Louis N. (Inventor); Wlezien, Richard W. (Inventor); Won, Chin C. (Inventor); Garg, Sanjay (Inventor)

    1998-01-01

    A method and system are provided for reducing flow-induced resonance in a structure's cavity. A time-varying disturbance is introduced into the flow along a leading edge of the cavity. The time-varying disturbance can be periodic and can have the same or different frequency of the natural resonant frequency of the cavity. In one embodiment of the system, flaps are mounted flush with the surface of the structure along the cavity's leading edge. A piezoelectric actuator is coupled to each flap and causes a portion of each flap to oscillate into and out of the flow in accordance with the time-varying function. Resonance reduction can be achieved with both open-loop and closed-loop configurations of the system.

  6. High Precision GPS Measurements

    DTIC Science & Technology

    2010-02-28

    GNSS Service (IGS) database, and magnetic field vectors from the International Geomagnetic Reference Field (IGRF) model [9]. These combined...Additonal correlations between the higher order range error and geomagnetic activity and seasonal variations are also obtained. Fig. 4 shows...clear correlation between the geomagnetic activity and enhanced higher order error at both sites. High Precision GPS Final Report Page 5 Fig.3

  7. Diagnostic resonant cavity for a charged particle accelerator

    DOEpatents

    Barov, Nikolai

    2007-10-02

    Disclosed is a diagnostic resonant cavity for determining characteristics of a charged particle beam, such as an electron beam, produced in a charged particle accelerator. The cavity is based on resonant quadrupole-mode and higher order cavities. Enhanced shunt impedance in such cavities is obtained by the incorporation of a set of four or more electrically conductive rods extending inwardly from either one or both of the end walls of the cavity, so as to form capacitive gaps near the outer radius of the beam tube. For typical diagnostic cavity applications, a five-fold increase in shunt impedance can be obtained. In alternative embodiments the cavity may include either four or more opposing pairs of rods which extend coaxially toward one another from the opposite end walls of the cavity and are spaced from one another to form capacitative gaps; or the cavity may include a single set of individual rods that extend from one end wall to a point adjacent the opposing end wall.

  8. Cyclicity of laryngeal cavity resonance due to vocal fold vibration.

    PubMed

    Kitamura, Tatsuya; Takemoto, Hironori; Adachi, Seiji; Mokhtari, Parham; Honda, Kiyoshi

    2006-10-01

    Acoustic effects of the time-varying glottal area due to vocal fold vibration on the laryngeal cavity resonance were investigated based on vocal tract area functions and acoustic analysis. The laryngeal cavity consists of the vestibular and ventricular parts of the larynx, and gives rise to a regional acoustic resonance within the vocal tract, with this resonance imparting an extra formant to the vocal tract resonance pattern. Vocal tract transfer functions of the five Japanese vowels uttered by three male subjects were calculated under open- and closed-glottis conditions. The results revealed that the resonance appears at the frequency region from 3.0 to 3.7 kHz when the glottis is closed and disappears when it is open. Real spectra estimated from open- and closed-glottis periods of vowel sounds also showed the on-off pattern of the resonance within a pitch period. Furthermore, a time-domain acoustic analysis of vowels indicated that the resonance component could be observed as a pitch-synchronized rise-and-fall pattern of the bandpass amplitude. The cyclic nature of the resonance can be explained as the laryngeal cavity acting as a closed tube that generates the resonance during a closed-glottis period, but damps the resonance off during an open-glottis period.

  9. Control of Cavity Resonance Using Steady and Oscillatory Blowing

    NASA Technical Reports Server (NTRS)

    Lamp, Alison M.; Chokani, Ndaona

    1999-01-01

    An experimental study to investigate the effect of steady and oscillatory (with zero net mass flux) blowing on cavity resonance is undertaken. The objective is to study the basic mechanisms of the control of cavity resonance. An actuator is designed and calibrated to generate either steady blowing or oscillatory blowing with A zero net mass flux. The results of the experiment show that both steady and oscillatory blowing are effective, and reduce the amplitude of the dominant resonant mode by 1OdB. The oscillatory blowing is however found to be more superior in that the same effectiveness could be accomplished with a momentum coefficient an order of magnitude smaller than for steady blowing. The experiment also confirms the results of previous computations that suggest the forcing frequency for oscillatory blowing must not be at harmonic frequencies of the cavity resonant modes.

  10. Resonant-cavity apparatus for cytometry or particle analysis

    DOEpatents

    Gourley, Paul L.

    1998-01-01

    A resonant-cavity apparatus for cytometry or particle analysis. The apparatus comprises a resonant optical cavity having an analysis region within the cavity for containing one or more biological cells or dielectric particles to be analyzed. In the presence of a cell or particle, a light beam in the form of spontaneous emission or lasing is generated within the resonant optical cavity and is encoded with information about the cell or particle. An analysis means including a spectrometer and/or a pulse-height analyzer is provided within the apparatus for recovery of the information from the light beam to determine a size, shape, identification or other characteristics about the cells or particles being analyzed. The recovered information can be grouped in a multi-dimensional coordinate space for identification of particular types of cells or particles. In some embodiments of the apparatus, the resonant optical cavity can be formed, at least in part, from a vertical-cavity surface-emitting laser. The apparatus and method are particularly suited to the analysis of biological cells, including blood cells, and can further include processing means for manipulating, sorting, or eradicating cells after analysis thereof.

  11. Resonant-cavity apparatus for cytometry or particle analysis

    DOEpatents

    Gourley, P.L.

    1998-08-11

    A resonant-cavity apparatus for cytometry or particle analysis is described. The apparatus comprises a resonant optical cavity having an analysis region within the cavity for containing one or more biological cells or dielectric particles to be analyzed. In the presence of a cell or particle, a light beam in the form of spontaneous emission or lasing is generated within the resonant optical cavity and is encoded with information about the cell or particle. An analysis means including a spectrometer and/or a pulse-height analyzer is provided within the apparatus for recovery of the information from the light beam to determine a size, shape, identification or other characteristics about the cells or particles being analyzed. The recovered information can be grouped in a multi-dimensional coordinate space for identification of particular types of cells or particles. In some embodiments of the apparatus, the resonant optical cavity can be formed, at least in part, from a vertical-cavity surface-emitting laser. The apparatus and method are particularly suited to the analysis of biological cells, including blood cells, and can further include processing means for manipulating, sorting, or eradicating cells after analysis. 35 figs.

  12. Cavity-enhanced continuous graphene plasmonic resonator for infrared sensing

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Nong, Jinpeng; Zhu, Yong; Tang, Linlong; Zhang, Guiwen; Yang, Jun; Huang, Yu; Wei, Dapeng

    2017-07-01

    We propose a cavity-enhanced resonator based on graphene surface plasmonics for infrared sensing. In such a resonator, a continuous and non-patterned monolayer graphene serves as the sensing medium by exciting surface plasmons on its surface, which can preserve the excellent electronic property of graphene and avoid the interaction between biomolecules and dielectric substrate. To improve its sensing performance, an optical cavity is employed to enhance the coupling of the incident light with the resonator. Simulation results demonstrate that the reflection spectra of the resonator can be modified to be narrower and deeper to improve the figure of merit (FOM) of the device significantly by adjusting the structure parameters of the cavity and the Fermi energy level. The FOM can achieve a high value of up to 20.15 RIU-1, which is about twice larger than that of the traditional structure without a cavity. Furthermore, the resonator can work in a wide angle range of the incident light. Such a plasmonic resonator with excellent features may provide a strategy to engineer graphene-based SPR sensor with high detection accuracy.

  13. Optical trapping of dielectric nanoparticles in resonant cavities

    SciTech Connect

    Hu Juejun; Lin Shiyun; Crozier, Kenneth; Kimerling, Lionel C.

    2010-11-15

    We theoretically investigate the opto-mechanical interactions between a dielectric nanoparticle and the resonantly enhanced optical field inside a high Q, small-mode-volume optical cavity. We develop an analytical method based on open system analysis to account for the resonant perturbation due to particle introduction and predict trapping potential in good agreement with three-dimensional (3D) finite-difference time-domain (FDTD) numerical simulations. Strong size-dependent trapping dynamics distinctly different from free-space optical tweezers arise as a consequence of the finite cavity perturbation. We illustrate single nanoparticle trapping from an ensemble of monodispersed particles based on size-dependent trapping dynamics. We further discover that the failure of the conventional dipole approximation in the case of resonant cavity trapping originates from a new perturbation interaction mechanism between trapped particles and spatially localized photons.

  14. Indirect coupling between two cavity modes via ferromagnetic resonance

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    We experimentally realize an indirect coupling between two cavity modes via strong coupling with ferromagnetic resonance in Yttrium Iron Garnet. We find that some indirectly coupled modes of this 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. The properties of the indirectly coupled modes can be controlled using an external magnetic field or by tuning the cavity height. The relation between cavity transmission and the relative phase difference between cavity modes should be useful for developing tunable optical devices and improved information processing technologies.

  15. Harmonically resonant cavity as a bunch-length monitor

    NASA Astrophysics Data System (ADS)

    Roberts, B.; Hannon, F.; Ali, M. M.; Forman, E.; Grames, J.; Kazimi, R.; Moore, W.; Pablo, M.; Poelker, M.; Sanchez, A.; Speirs, D.

    2016-05-01

    A compact, harmonically resonant cavity with fundamental resonant frequency 1497 MHz was used to evaluate the temporal characteristics of electron bunches produced by a 130 kV dc high voltage spin-polarized photoelectron source at the Continuous Electron Beam Accelerator Facility (CEBAF) photoinjector, delivered at 249.5 and 499 MHz repetition rates and ranging in width from 45 to 150 picoseconds (FWHM). A cavity antenna attached directly to a sampling oscilloscope detected the electron bunches as they passed through the cavity bore with a sensitivity of ˜1 mV /μ A . The oscilloscope waveforms are a superposition of the harmonic modes excited by the beam, with each cavity mode representing a term of the Fourier series of the electron bunch train. Relatively straightforward post-processing of the waveforms provided a near-real time representation of the electron bunches revealing bunch-length and the relative phasing of interleaved beams. The noninvasive measurements from the harmonically resonant cavity were compared to measurements obtained using an invasive RF-deflector-cavity technique and to predictions from particle tracking simulations.

  16. Resonant-cavity antenna for plasma heating

    DOEpatents

    Perkins, F.W. Jr.; Chiu, S.C.; Parks, P.; Rawls, J.M.

    1984-01-10

    This invention relates generally to a method and apparatus for transferring energy to a plasma immersed in a magnetic field, and relates particularly to an apparatus for heating a plasma of low atomic number ions to high temperatures by transfer of energy to plasma resonances, particularly the fundamental and harmonics of the ion cyclotron frequency of the plasma ions. This invention transfers energy from an oscillating radio-frequency field to a plasma resonance of a plasma immersed in a magnetic field.

  17. On the calibration of continuous, high-precision delta18O and delta2H measurements using an off-axis integrated cavity output spectrometer.

    PubMed

    Wang, Lixin; Caylor, Kelly K; Dragoni, Danilo

    2009-02-01

    The (18)O and (2)H of water vapor serve as powerful tracers of hydrological processes. The typical method for determining water vapor delta(18)O and delta(2)H involves cryogenic trapping and isotope ratio mass spectrometry. Even with recent technical advances, these methods cannot resolve vapor composition at high temporal resolutions. In recent years, a few groups have developed continuous laser absorption spectroscopy (LAS) approaches for measuring delta(18)O and delta(2)H which achieve accuracy levels similar to those of lab-based mass spectrometry methods. Unfortunately, most LAS systems need cryogenic cooling and constant calibration to a reference gas, and have substantial power requirements, making them unsuitable for long-term field deployment at remote field sites. A new method called Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) has been developed which requires extremely low-energy consumption and neither reference gas nor cryogenic cooling. In this report, we develop a relatively simple pumping system coupled to a dew point generator to calibrate an ICOS-based instrument (Los Gatos Research Water Vapor Isotope Analyzer (WVIA) DLT-100) under various pressures using liquid water with known isotopic signatures. Results show that the WVIA can be successfully calibrated using this customized system for different pressure settings, which ensure that this instrument can be combined with other gas-sampling systems. The precisions of this instrument and the associated calibration method can reach approximately 0.08 per thousand for delta(18)O and approximately 0.4 per thousand for delta(2)H. Compared with conventional mass spectrometry and other LAS-based methods, the OA-ICOS technique provides a promising alternative tool for continuous water vapor isotopic measurements in field deployments.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Resonant-cavity ICRF coupler for large tokamaks

    SciTech Connect

    Perkins, F.W.; Kluge, R.F.

    1983-04-01

    A new resonant-cavity ICRF coupler is proposed for large tokamaks. The design features a novel resonant cavity, an rf magnetic-field orientation that effectively radiates fast Alfven waves, matching to 40 ..cap omega.. transmission lines, and an electric-field orientation so that the strongest rf electric fields are orthogonal to the main toroidal magnetic field thereby benefitting from magnetic insulation. As a result, the power handling capability is excellent. For the case of the Big-Dee Doublet III tokamak, a single 35 cm x 50 cm coupler can launch 20 MW of fast Alfven waves. Extrapolation to fusion reactor parameters is straightforward.

  20. Nondegenerate Parametric Resonance in a Tunable Superconducting Cavity

    NASA Astrophysics Data System (ADS)

    Wustmann, Waltraut; Shumeiko, Vitaly

    2017-08-01

    We develop a theory for nondegenerate parametric resonance in a tunable superconducting cavity. We focus on nonlinear effects that are caused by nonlinear Josephson elements connected to the cavity. We analyze parametric amplification in a strong nonlinear regime at the parametric-instability threshold, and we calculate maximum gain values. Above the threshold, in the parametric-oscillator regime, the cavity linear response diverges at the oscillator frequency at all pump strengths. We show that this divergence is related to the continuous degeneracy of the free oscillator state with respect to the phase. Applying on-resonance input lifts the degeneracy and removes the divergence. We also investigate quantum noise squeezing. It is shown that in the strong amplification regime, the noise undergoes four-mode squeezing, and that, in this regime, the output signal-to-noise ratio can significantly exceed the input value. We also analyze the intermode frequency conversion and identify the parameters at which full conversion is achieved.

  1. Mid-Infrared Tunable Resonant Cavity Enhanced Detectors

    PubMed Central

    Quack, Niels; Blunier, Stefan; Dual, Jurg; Felder, Ferdinand; Arnold, Martin; Zogg, Hans

    2008-01-01

    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). PMID:27873824

  2. Long-base free electron laser resonant cavity

    SciTech Connect

    Miller, E.L.; Bender, S.C.; Appert, Q.D.; Saxman, A.C.; Swann, T.A.

    1985-01-01

    A 65-meter resonant cavity has been constructed in order to experimentally determine the characteristics of long resonant cavities as would be required for a free electron laser (FEL). A version using normal incidence mirrors is reported here, and another that includes a grazing incidence mirror is forthcoming. Either version is designed to simulate a FEL operating at 0.5 micron wavelength and is near-concentric with a stability parameter of 0.98. Argon-ion plasma tubes simulate the laser gain that would be provided by a wiggler in an actual FEL. The cavity was constructed on a seismic slab and air turbulence effects were reduced by surrounding the beam with helium in 6 in. diameter tubes. Alignment sensitivities are reported and compared to geometrical and diffraction predictions with good agreement.

  3. Cyclotron Resonance of Electrons Trapped in a Microwave Cavity

    ERIC Educational Resources Information Center

    Elmore, W. C.

    1975-01-01

    Describes an experiment in which the free-electron cyclotron resonance of electrons trapped in a microwave cavity by a Penning trap is observed. The experiment constitutes an attractive alternative to one of the Gardner-Purcell variety. (Author/GS)

  4. Whispering Gallery Mode Resonators as Optical Reference Cavities

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  5. Resonant cavity spectroscopy of radical species

    NASA Astrophysics Data System (ADS)

    Ritchie, Grant

    2015-04-01

    Photo-oxidation in the troposphere is highly complex, being initiated by short lived radical species, in the daytime dominated by the hydroxyl radical, OH, with contributions from Cl atoms, and at night by either NO3 radicals or ozone. Chemical oxidation cycles, which couple OH, HO2 and peroxy (RO2) radical species, remove primary emitted trace species which are harmful to humans or to the wider environment. However, many of the secondary products produced by atmospheric photo-oxidation are also directly harmful, for example O3, NO2, acidic and multifunctional species, many of which are of low volatility and are able to partition effectively to the condensed phase, creating secondary organic aerosol (SOA), which contributes a significant fraction of tropospheric aerosol, with associated impacts on climate and human health. The accuracy of atmospheric models to predict these impacts necessarily requires accurate knowledge of the chemical oxidative cycling. Two of the simplest intermediates are the hydroperoxy radical, HO2, and the smallest and dominant organic peroxy radical, CH3O2, formed directly by the reactions of OH with CO/O2 and CH4/O2, respectively, and indirectly following the oxidation of larger VOCs. OH, HO2 and RO2 (collectively known as ROx) are rapidly cycled, being at the centre of tropospheric oxidation, and hence are some of the best targets for models to compare with field data. The reaction of HO2 and RO2 with NO constitutes the only tropospheric in-situ source of O3. Despite their importance, neither HO2 nor CH3O2 is measured directly in the atmosphere. HO2 is only measured indirectly following its conversion to OH and CH3O2 is not measured at all. Typically only the sum of RO2 radicals is measured, making no distinction between different organic peroxy radicals. This contribution will detail recent studies using (i) optical feedback cavity enhanced absorption spectroscopy with both quantum and inter-band cascade lasers in the mid-IR, and (ii

  6. Generating Second Harmonics In Nonlinear Resonant Cavities

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    Single-axial-mode lasers pump very-low-loss doubling crystals. Important advance in making resonant generation of second harmonics possible for diode-laser-pumped solid-state lasers is recent development of monolithic nonplanar ring geometries in neodymium:yttrium aluminum garnet (Nd:YAG) lasers that produce frequency-stable single-mode outputs. Other advance is development of high-quality MgO:LiNbO3 as electro-optically nonlinear material. Series of experiments devised to improve doubling efficiency of low-power lasers, and particularly of diode-laser-pumped continuous-wave Nd:YAG lasers.

  7. Terahertz Sensor Using Photonic Crystal Cavity and Resonant Tunneling Diodes

    NASA Astrophysics Data System (ADS)

    Okamoto, Kazuma; Tsuruda, Kazuisao; Diebold, Sebastian; Hisatake, Shintaro; Fujita, Masayuki; Nagatsuma, Tadao

    2017-09-01

    In this paper, we report on a terahertz (THz) sensing system. Compared to previously reported systems, it has increased system sensitivity and reduced size. Both are achieved by using a photonic crystal (PC) cavity as a resonator and compact resonant tunneling diodes (RTDs) as signal source and as detector. The measured quality factor of the PC cavity is higher than 10,000, and its resonant frequency is 318 GHz. To demonstrate the operation of the refractive index sensing system, dielectric tapes of various thicknesses are attached to the PC cavity and the change in the resonator's refractive index is measured. The figure of merit of refractive index sensing using the developed system is one order higher than that of previous studies, which used metallic metamaterial resonators. The frequency of the RTD-based source can be swept from 316 to 321 GHz by varying the RTD direct current voltage. This effect is used to realize a compact frequency tunable signal source. Measurements using a commercial signal source and detector are carried out to verify the accuracy of the data obtained using RTDs as a signal source and as a detector.

  8. Cavity-enhanced resonant tunneling photodetector at telecommunication wavelengths

    SciTech Connect

    Pfenning, Andreas Hartmann, Fabian; Langer, Fabian; Höfling, Sven; Kamp, Martin; Worschech, Lukas

    2014-03-10

    An AlGaAs/GaAs double barrier resonant tunneling diode (RTD) with a nearby lattice-matched GaInNAs absorption layer was integrated into an optical cavity consisting of five and seven GaAs/AlAs layers to demonstrate cavity enhanced photodetection at the telecommunication wavelength 1.3 μm. The samples were grown by molecular beam epitaxy and RTD-mesas with ring-shaped contacts were fabricated. Electrical and optical properties were investigated at room temperature. The detector shows maximum photocurrent for the optical resonance at a wavelength of 1.29 μm. At resonance a high sensitivity of 3.1×10{sup 4} A/W and a response up to several pA per photon at room temperature were found.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Acoustically driven programmable liquid motion using resonance cavities

    PubMed Central

    Langelier, Sean M.; Chang, Dustin S.; Zeitoun, Ramsey I.; Burns, Mark A.

    2009-01-01

    Performance and utility of microfluidic systems are often overshadowed by the difficulties and costs associated with operation and control. As a step toward the development of a more efficient platform for microfluidic control, we present a distributed pressure generation scheme whereby independently tunable pressure sources can be simultaneously controlled by using a single acoustic source. We demonstrate how this scheme can be used to perform precise droplet positioning as well as merging, splitting, and sorting within open microfluidic networks. We further show how this scheme can be implemented for control of continuous-flow systems, specifically for generation of acoustically tunable liquid gradients. Device operation hinges on a resonance-decoding and rectification mechanism by which the frequency content in a composite acoustic input is decomposed into multiple independently buffered output pressures. The device consists of a bank of 4 uniquely tuned resonance cavities (404, 484, 532, and 654 Hz), each being responsible for the actuation of a single droplet, 4 identical flow-rectification structures, and a single acoustic source. Cavities selectively amplify resonant tones in the input signal, resulting in highly elevated local cavity pressures. Fluidic-rectification structures then serve to convert the elevated oscillating cavity pressures into unidirectional flows. The resulting pressure gradients, which are used to manipulate fluids in a microdevice, are tunable over a range of ≈0–200 Pa with a control resolution of 10 Pa. PMID:19620719

  11. Grating tuned unstable resonator laser cavity

    DOEpatents

    Johnson, Larry C.

    1982-01-01

    An unstable resonator to be used in high power, narrow line CO.sub.2 pump lasers comprises an array of four reflectors in a ring configuration wherein spherical and planar wavefronts are separated from each other along separate optical paths and only the planar wavefronts are impinged on a plane grating for line tuning. The reflector array comprises a concave mirror for reflecting incident spherical waves as plane waves along an output axis to form an output beam. A plane grating on the output axis is oriented to reflect a portion of the output beam off axis onto a planar relay mirror spaced apart from the output axis in proximity to the concave mirror. The relay mirror reflects plane waves from the grating to impinge on a convex expanding mirror spaced apart from the output axis in proximity to the grating. The expanding mirror reflects the incident planar waves as spherical waves to illuminate the concave mirror. Tuning is provided by rotating the plane grating about an axis normal to the output axis.

  12. Fano resonances in a plasmonic waveguide system composed of stub coupled with a square cavity resonator

    NASA Astrophysics Data System (ADS)

    Binfeng, Yun; Hu, Guohua; Zhang, Ruohu; Yiping, Cui

    2016-05-01

    A coupled plasmonic waveguide resonator system which can produce sharp and asymmetric Fano resonances was proposed and analyzed. Two Fano resonances are induced by the interactions between the narrow discrete whispering gallery modes in a plasmonic square cavity resonator and the broad spectrum of the metal-insulator-metal stub resonator. The relative peak amplitudes between the 1st and 2nd order Fano resonances can be adjusted by changing the structure parameters, such as the square cavity size, the stub size and the center-to-center distance between the square cavity and the stub resonators. And the 1st order Fano resonant peak, which is a standing-wave mode, will split into two resonant peaks (one standing-wave mode and one traveling-wave mode) when it couples with the 2nd Fano resonance. Also, the potential of the proposed Fano system as an integrated slow-light device and refractive index sensor was investigated. The results show that a maximum group index of about 100 can be realized, and a linear refractive index sensitivity of 938 nm/RIU with a figure of merit of about 1.35 × 104 can be obtained.

  13. High Precision Measurement of Resonance States in 18Ne , 30S , and 38Ca Nuclei using the (p,t) Reaction, and Reaction Rates in the αp- and rp-Processes

    NASA Astrophysics Data System (ADS)

    Adachi, T.; Berg, G. P. A.; Buthelezi, E. Z.; Carter, J.; Couder, M.; Fearick, R.; Förtsch, S. V.; Görres, J.; Kheswa, Y.; Mira, J.; Murray, S.; Neveling, R.; Papka, P.; Sideras-Haddad, E.; Smit, F. D.; Swartz, J. A.; Talwar, R.; Usman, I.; van Zyl, J. J.; Wiescher, M.; O'Brien, S.

    2011-10-01

    Thermonuclear runaway reactions in type 1 X-ray burst are trigged by the breakout from the hot CNO cycles and is subsequently driven by αp- and rp-processes. These time scales for the αp- and rp-process are determined by the associated reaction rates, which depend exponentially on the associated resonance energies. High precision (p,t) measurement were preformed at iThemba LABS to examine resonance states in 18Ne , 30S , and 38Ca nuclei using the K600 spectrometer with a dispersion matched beam. Preliminary analysis will be presented.

  14. Extended-cavity diode lasers with tracked resonances

    NASA Astrophysics Data System (ADS)

    Chiow, Sheng-Wey; Long, Quan; Vo, Christoph; Müller, Holger; Chu, Steven

    2007-11-01

    We present a painless, almost-free upgrade to present extended-cavity diode lasers (ECDLs) that improves the long-term mode-hop-free performance by stabilizing the resonance of the internal cavity to the external cavity. This stabilization is based on the observation that the frequency or amplitude noise of the ECDL is lowest at the optimum laser diode temperature or injection current. Thus, keeping the diode current at the level where the noise is lowest ensures mode-hop-free operation within one of the stable regions of the mode chart, even if these should drift due to external influences. This method can be applied directly to existing laser systems without modifying the optical setup. We demonstrate the method in two ECDLs stabilized to vapor cells at 852 and 895 nm wavelengths. We achieve long-term mode-hop-free operation and low noise at low power consumption, even with an inexpensive non-antireflection-coated diode.

  15. Extended-cavity diode lasers with tracked resonances.

    PubMed

    Chiow, Sheng-Wey; Long, Quan; Vo, Christoph; Müller, Holger; Chu, Steven

    2007-11-20

    We present a painless, almost-free upgrade to present extended-cavity diode lasers (ECDLs) that improves the long-term mode-hop-free performance by stabilizing the resonance of the internal cavity to the external cavity. This stabilization is based on the observation that the frequency or amplitude noise of the ECDL is lowest at the optimum laser diode temperature or injection current. Thus, keeping the diode current at the level where the noise is lowest ensures mode-hop-free operation within one of the stable regions of the mode chart, even if these should drift due to external influences. This method can be applied directly to existing laser systems without modifying the optical setup. We demonstrate the method in two ECDLs stabilized to vapor cells at 852 and 895 nm wavelengths. We achieve long-term mode-hop-free operation and low noise at low power consumption, even with an inexpensive non-antireflection-coated diode.

  16. Quasistatic Cavity Resonance for Ubiquitous Wireless Power Transfer.

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Quasistatic Cavity Resonance for Ubiquitous Wireless Power Transfer

    PubMed Central

    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

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

    PubMed

    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.

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

    PubMed

    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.

  1. Broadband electron spin resonance at low frequency without resonant cavity

    SciTech Connect

    Jang, Z.; Suh, B.; Corti, M.; Cattaneo, L.; Hajny, D.; Borsa, F.; Luban, M.

    2008-04-09

    We have developed a nonconventional broadband electron spin resonance (ESR) spectrometer operating continuously in the frequency range from 0.5 to 9 GHz. Dual antenna structure and the microwave absorbing environment differentiate the setup from the conventional one and enable broadband operation with any combination of frequency or magnetic field modulation and frequency or magnetic field sweeping. Its performance has been tested with the measurements on a 1,1-diphenyl-2-picrylhydrazyl (DPPH) sample and with the measurements on the single molecular magnet, V6, in solid state at low temperature.

  2. High precision laser sclerostomy

    NASA Astrophysics Data System (ADS)

    Góra, W. S.; Urich, A.; McIntosh, L.; Carter, R. M.; Wilson, C. G.; Dhillon, B.; Hand, D. P.; Shephard, J. D.

    2015-03-01

    Ultrafast lasers offer a possibility of removing soft ophthalmic tissue without introducing collateral damage at the ablation site or in the surrounding tissue. The potential for using ultrashort pico- and femtosecond pulse lasers for modification of ophthalmic tissue has been reported elsewhere and has resulted in the introduction of new, minimally invasive procedures into clinical practice. Our research aims to define the most efficient parameters to allow for the modification of scleral tissue without introducing collateral damage. Our experiments were carried out on hydrated porcine sclera in vitro. Porcine sclera, which has similar collagen organization, histology and water content (~70%) to human tissue was used. Supporting this work we present a 2D finite element blow-off model which employs a one-step heating process. It is assumed that the incident laser radiation that is not reflected is absorbed in the tissue according to the Beer-Lambert law and transformed into heat energy. The experimental setup uses an industrial picosecond laser (TRUMPF TruMicro 5x50) with 5.9 ps pulses at 1030 nm, with pulse energies up to 125 μJ and a focused spot diameter of 35 μm. Use of a beam steering scan head allows flexibility in designing complicated scanning patterns. In this study we have demonstrated that picosecond pulses are capable of removing scleral tissue without introducing any major thermal damage which offers a possible route for minimally invasive sclerostomy. In assessing this we have tested several different scanning patterns including single line ablation, square and circular cavity removal.

  3. Dielectric microwave resonators in TE011 cavities for electron paramagnetic resonance spectroscopy

    PubMed Central

    Mett, Richard R.; Sidabras, Jason W.; Golovina, Iryna S.; Hyde, James S.

    2008-01-01

    The coupled system of the microwave cylindrical TE011 cavity and the TE01δ dielectric modes has been analyzed in order to determine the maximum achievable resonator efficiency parameter of a dielectric inserted into a cavity, and whether this value can exceed that of a dedicated TE01δ mode dielectric resonator. The frequency, Q value, and resonator efficiency parameter Λ for each mode of the coupled system were calculated as the size of the dielectric was varied. Other output parameters include the relative field magnitudes and phases. Two modes are found: one with fields in the dielectric parallel to the fields in the cavity center and the other with antiparallel fields. Results closely match those from a computer program that solves Maxwell’s equations by finite element methods. Depending on the relative natural resonance frequencies of the cavity and dielectric, one mode has a higher Q value and correspondingly lower Λ than the other. The mode with the higher Q value is preferentially excited by a coupling iris or loop in or near the cavity wall. However, depending on the frequency separation between modes, either can be excited in this way. A relatively narrow optimum is found for the size of the insert that produces maximum signal for both modes simultaneously. It occurs when the self-resonance frequencies of the two resonators are nearly equal. The maximum signal is almost the same as that of the dedicated TE01δ mode dielectric resonator alone, Λ≅40 G∕W1∕2 at X-band for a KTaO3 crystal. The cavity is analogous to the second stage of a two-stage coupler. In general, there is no electron paramagnetic resonance (EPR) signal benefit by use of a second stage. However, there is a benefit of convenience. A properly designed sample-mounted resonator inserted into a cavity can give EPR signals as large as what one would expect from the dielectric resonator alone. PMID:19044441

  4. A 10-GHz film-thickness-mode cavity optomechanical resonator

    NASA Astrophysics Data System (ADS)

    Han, Xu; Fong, King Y.; Tang, Hong X.

    2015-04-01

    We report on the advance of chip-scale cavity optomechanical resonators to beyond 10 GHz by exploiting the fundamental acoustic thickness mode of an aluminum nitride micro-disk. By engineering the mechanical anchor to minimize the acoustic loss, a quality factor of 1830 and hence a frequency-quality factor product of 1.9 × 1013 Hz are achieved in ambient air at room temperature. Actuated by strong piezo-electric force, the micro-disk resonator shows an excellent electro-optomechanical transduction efficiency. Our detailed analysis of the electro-optomechanical coupling allows identification and full quantification of various acoustic modes spanning from super-high to X-band microwave frequencies measured in the thin film resonator.

  5. Cavity Cooling of A Mechanical Resonator in Amorphous Systems

    NASA Astrophysics Data System (ADS)

    Tian, Lin

    2011-03-01

    The quantum backaction force generated by a cavity coupled with a mechanical resonator can be exploited to achieve sideband cooling of the mechanical mode. By applying a red-detuned driving, the quantum ground state of the mechanical mode can be reached in the resolved-sideband regime, which has recently be demonstrated in experiments. However, in many of these materials, surface defects or adsorbates can couple with the mechanical mode and impair the cavity cooling. These defects can be treated as quantum two-level system (TLS). The mechanical vibration changes the local strain tensor and generates coupling with the TLS via the deformation potential. In this work, we study the cavity cooling of the mechanical mode in the presence of a TLS. By applying the adiabatic elimination technique widely used in quantum optics, we derive the cooling master equation for the resonator-TLS system in the eigenbasis of this system. Our results show that the stationary phonon number depends non- monotonically on the energy of the TLS. We also show that the cooling depends strongly on the decoherence rate of the TLS. This work is supported by the DARPA/MTO ORCHID program through AFOSR, NSF-DMR-0956064, NSF-CCF-0916303, and NSF COINS program.

  6. Crystal cavity resonance for hard x rays: A diffraction experiment

    SciTech Connect

    Chang, S.-L.; Stetsko, Yu. P.; Tang, M.-T.; Shew, B.-Y.; Lee, Y.-R.; Sun, W.-H.; Wu, H.-H.; Kuo, T.-T.; Chen, S.-Y.; Chang, Y.-Y.; Shy, J.-T.; Yabashi, M.; Tamasaku, K.; Miwa, D.

    2006-10-01

    We report the details of the recent x-ray back diffraction experiments, in which interference fringes due to x-ray cavity resonance are unambiguously observed. The Fabry-Perot type cavities, the tested crystal devices of reflectivity R{approx_equal}0.5 and finesse F{approx_equal}2.3, consist of monolithic two-plate and eight-plate silicon crystals. They were prepared by using x-ray lithographic techniques. The thicknesses of the crystal plates and the gaps between the two adjacent plates are a few tens to hundreds {mu}m. The (12 4 0) back reflection and synchrotron x-radiation of energy resolution {delta}E=0.36 meV at 14.4388 keV are employed. Interference fringes in angle- and photon-energy scans for two-plate and eight-plate cavities are shown. Considerations on the temporal and spatial coherence for observable resonance interference fringes using synchrotron x-rays are presented. The details about the accompanied simultaneous 24-beam diffraction in relation to x-ray photon energy are also described.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Total body water measurements using resonant cavity perturbation techniques

    NASA Astrophysics Data System (ADS)

    Stone, Darren A.; Robinson, Martin P.

    2004-05-01

    A recent paper proposed a novel technique for determining the total body water (TBW) of patients suffering with abnormal hydration levels, using a resonant cavity perturbation method. Current techniques to measure TBW are limited by resolution and technical constraints. However, this new method involves measuring the dielectric properties of the body, by placing a subject in a large cavity resonator and measuring the subsequent change in its resonant frequency, fres and its Q-factor. Utilizing the relationship that water content correlates to these dielectric properties, it has been shown that the measured response of these parameters enables determination of TBW. Results are presented for a preliminary study using data estimated from anthropometric measurements, where volunteers were asked to lie and stand in an electromagnetic screened room, before and after drinking between 1 and 2 l of water, and in some cases, after voiding the bladder. Notable changes in the parameters were observed; fres showed a negative shift and Q was reduced. Preliminary calibration curves using estimated values of water content have been developed from these results, showing that for each subject the measured resonant frequency is a linear function of TBW. Because the gradients of these calibration curves correlate to the mass-to-height-ratio of the volunteers, it has proved that a system in which TBW can be unequivocally obtained is possible. Measured values of TBW have been determined using this new pilot-technique, and the values obtained correlate well with theoretical values of body water (r = 0.87) and resolution is very good (750 ml). The results obtained are measurable, repeatable and statistically significant. This leads to confidence in the integrity of the proposed technique.

  9. The advantage of linear viscoelastic material behavior in passive damper design-with application in broad-banded resonance dampers for industrial high-precision motion stages

    NASA Astrophysics Data System (ADS)

    Verbaan, Cornelis A. M.; Peters, Gerrit W. M.; Steinbuch, Maarten

    2017-01-01

    In this paper we demonstrate the advantage of applying viscoelastic materials instead of purely viscous materials as damping medium in mechanical dampers. Although the loss modulus decreases as function of frequency in case of viscoelastic behavior, which can be interpreted as a decrease of damping, the viscoelastic behavior still leads to an increased modal damping for mechanical structures. This advantage holds for inertial-mass-type dampers that are tuned for broad-banded resonance damping. It turns out that an increase of the storage modulus as function of frequency contributes to the effectiveness of mechanical dampers with respect to energy dissipation at different mechanical resonance frequencies. It is shown that this phenomenon is medium specific and is independent of the amount of damper mass.

  10. Degenerate four-wave mixing in triply resonant Kerr cavities

    NASA Astrophysics Data System (ADS)

    Ramirez, David M.; Rodriguez, Alejandro W.; Hashemi, Hila; Joannopoulos, J. D.; Soljačić, Marin; Johnson, Steven G.

    2011-03-01

    We demonstrate theoretical conditions for highly efficient degenerate four-wave mixing in triply resonant nonlinear (Kerr) cavities. We employ a general and accurate temporal coupled-mode analysis in which the interaction of light in arbitrary microcavities is expressed in terms of a set of coupling coefficients that we rigorously derive from the full Maxwell equations. Using the coupled-mode theory, we show that light consisting of an input signal of frequency ω0-Δω can, in the presence of pump light at ω0, be converted with quantum-limited efficiency into an output shifted signal of frequency ω0+Δω, and we derive expressions for the critical input powers at which this occurs. We find the critical powers in the order of 10 mW, assuming very conservative cavity parameters (modal volumes ~10 cubic wavelengths and quality factors ~1000). The standard Manley-Rowe efficiency limits are obtained from the solution of the classical coupled-mode equations, although we also derive them from simple photon-counting “quantum” arguments. Finally, using a linear stability analysis, we demonstrate that maximal conversion efficiency can be retained even in the presence of self- and cross-phase modulation effects that generally act to disrupt the resonance condition.

  11. Silicon resonant cavity enhanced photodetector arrays for optical interconnects

    NASA Astrophysics Data System (ADS)

    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.

  12. Surface conductance of graphene from non-contact resonant cavity

    PubMed Central

    Obrzut, Jan; Emiroglu, Caglar; Kirillov, Oleg; Yang, Yanfei; Elmquist, Randolph E.

    2016-01-01

    A method is established to reliably determine surface conductance of single-layer or multi-layer atomically thin nano-carbon graphene structures. The measurements are made in an air filled standard R100 rectangular waveguide configuration at one of the resonant frequency modes, typically at TE103 mode of 7.4543 GHz. Surface conductance measurement involves monitoring a change in the quality factor of the cavity as the specimen is progressively inserted into the cavity in quantitative correlation with the specimen surface area. The specimen consists of a nano-carbon-layer supported on a low loss dielectric substrate. The thickness of the conducting nano-carbon layer does not need to be explicitly known, but it is assumed that the lateral dimension is uniform over the specimen area. The non-contact surface conductance measurements are illustrated for a typical graphene grown by chemical vapor deposition process, and for a high quality monolayer epitaxial graphene grown on silicon carbide wafers for which we performed non-gated quantum Hall resistance measurements. The sequence of quantized transverse Hall resistance at the Landau filling factors ν = ±6 and ±2, and the absence of the Hall plateau at ν = 4 indicate that the epitaxially grown graphene is a high quality mono-layer. The resonant microwave cavity measurement is sensitive to the surface and bulk conductivity, and since no additional processing is required, it preserves the integrity of the conductive graphene layer. It allows characterization with high speed, precision and efficiency, compared to transport measurements where sample contacts must be defined and applied in multiple processing steps. PMID:27499569

  13. Proposal of using slot-waveguide cavity to reduce noises in resonant integrated optical gyroscopes

    NASA Astrophysics Data System (ADS)

    Jiang, Yi; Kong, Mei; Xu, Yameng

    2016-10-01

    Resonant optical gyroscopes suffer serious performance degradation induced by noises. We propose using an air-gap silicon-on-silica slot waveguide ring resonator as the resonant cavity of a resonant integrated optical gyroscope. We estimate possible backscattering, Kerr effect, polarization fluctuation, and thermal drift in the air-gap slot waveguide. It is shown that the backscattering, Kerr nonlinearity, and thermal instabilities can decrease significantly compared to those in a common solid-core silicon waveguide cavity, and perturbations of the polarization fluctuation may be eliminated. In addition, a slot-waveguide cavity is more beneficial for integration than a photonic bandgap fiber cavity.

  14. A 100 Mbps resonant cavity phase modulator for coherent optical communications

    NASA Technical Reports Server (NTRS)

    Chen, Chien-Chung; Robinson, Deborah L.; Hemmati, Hamid

    1992-01-01

    A resonant cavity electro-optic phase modulator has been designed and implemented to operate at a data rate of 100 Mbps. The modulator consists of an electro-optic crystal located in a highly resonant cavity. The cavity is electro-optically tuned on and off resonance, and the phase dispersion near the cavity resonance provides the output phase modulation. The performance of the modulator was measured by first heterodyne detecting the signal to an intermediate frequency and then measuring the spectral characteristics using an RF spectrum analyzer. The measured phase shift is shown to be in good agreement with the theoretical predictions.

  15. Resonant Optomechanics with a Vibrating Carbon Nanotube and a Radio-Frequency Cavity

    NASA Astrophysics Data System (ADS)

    Ares, N.; Pei, T.; Mavalankar, A.; Mergenthaler, M.; Warner, J. H.; Briggs, G. A. D.; Laird, E. A.

    2016-10-01

    In an optomechanical setup, the coupling between cavity and resonator can be increased by tuning them to the same frequency. We study this interaction between a carbon nanotube resonator and a radio-frequency tank circuit acting as a cavity. In this resonant regime, the vacuum optomechanical coupling is enhanced by the dc voltage coupling the cavity and the mechanical resonator. Using the cavity to detect the nanotube's motion, we observe and simulate interference between mechanical and electrical oscillations. We measure the mechanical ring down and show that further improvements to the system could enable the measurement of mechanical motion at the quantum limit.

  16. Resonant Optomechanics with a Vibrating Carbon Nanotube and a Radio-Frequency Cavity.

    PubMed

    Ares, N; Pei, T; Mavalankar, A; Mergenthaler, M; Warner, J H; Briggs, G A D; Laird, E A

    2016-10-21

    In an optomechanical setup, the coupling between cavity and resonator can be increased by tuning them to the same frequency. We study this interaction between a carbon nanotube resonator and a radio-frequency tank circuit acting as a cavity. In this resonant regime, the vacuum optomechanical coupling is enhanced by the dc voltage coupling the cavity and the mechanical resonator. Using the cavity to detect the nanotube's motion, we observe and simulate interference between mechanical and electrical oscillations. We measure the mechanical ring down and show that further improvements to the system could enable the measurement of mechanical motion at the quantum limit.

  17. A Micromachined Millimeter-Wave Cavity Resonator on Silicon and Quartz Substrates

    NASA Astrophysics Data System (ADS)

    Song, Ki-Jae; Yoon, Bup-Sang; Lee, Jong-Chul; Lee, Byungje; Kim, Jong-Heon; Kim, Nam-Young; Park, Jae-Yeong; Kim, Geun-Ho; Bu, Jong-Uk

    2001-12-01

    In this letter, a Ka-band cavity resonator using micromachining process is presented. A two-port cavity resonator is designed using the three-dimensional (3-D) design software, HP HFSS. The cavity resonator is fabricated on a Si substrate and bonded with a Quartz wafer. The resonator shows the resonant frequency of 39 GHz, the insertion loss of 4.6 dB, and the loaded quality factor (QL) and unloaded quality factor (QU) of 44.3 and 107, respectively.

  18. Cavity-resonator-integrated guided-mode resonance filter for aperture miniaturization.

    PubMed

    Kintaka, Kenji; Majima, Tatsuya; Inoue, Junichi; Hatanaka, Koji; Nishii, Junji; Ura, Shogo

    2012-01-16

    A guided-mode resonance filter integrated in a waveguide cavity resonator constructed by two distributed Bragg reflectors is designed and fabricated for miniaturization of aperture size. Reflection efficiency of >90% and wavelength selectivity of 0.4 nm are predicted in the designed SiO(2)-based filter with 50-μm aperture by a numerical calculation using the finite-difference time-domain method. A maximum reflectance of 67% with 0.5-nm bandwidth is experimentally demonstrated by the fabricated device at around 850-nm wavelength.

  19. Nuclear resonance tomography with a toroid cavity detector

    DOEpatents

    Woelk, K.; Rathke, J.W.; Klingler, R.J.

    1996-11-12

    A toroid cavity detection system is described for determining the spectral properties and distance from a fixed point for a sample using Nuclear Magnetic Resonance. The detection system consists of a toroid with a central conductor oriented along the main axis of the toroidal cylinder and perpendicular to a static uniform magnetic field oriented along the main axis of the toroid. An rf signal is input to the central conductor to produce a magnetic field perpendicular to the central axis of the toroid and whose field strength varies as the inverse of the radius of the toroid. The toroid cavity detection system can be used to encapsulate a sample, or the detection system can be perforated to allow a sample to flow into the detection device or to place the samples in specified sample tubes. The central conductor can also be coated to determine the spectral property of the coating and the coating thickness. The sample is then subjected to the respective magnetic fields and the responses measured to determine the desired properties. 4 figs.

  20. Nuclear resonance tomography with a toroid cavity detector

    DOEpatents

    Woelk, Klaus; Rathke, Jerome W.; Klingler, Robert J.

    1996-01-01

    A toroid cavity detection system for determining the spectral properties and distance from a fixed point for a sample using Nuclear Magnetic Resonance. The detection system consists of a toroid with a central conductor oriented along the main axis of the toroidal cylinder and perpendicular to a static uniform magnetic field oriented along the main axis of the toroid. An rf signal is inputted to the central conductor to produce a magnetic field perpendicular to the central axis of the toroid and whose field strength varies as the inverse of the radius of the toroid. The toroid cavity detection system can be used to encapsulate a sample, or the detection system can be perforated to allow a sample to flow into the detection device or to place the samples in specified sample tubes. The central conductor can also be coated to determine the spectral property of the coating and the coating thickness. The sample is then subjected to the respective magnetic fields and the responses measured to determine the desired properties.

  1. High-speed Si resonant cavity enhanced photodetectors and arrays

    NASA Astrophysics Data System (ADS)

    Ünlü, M. S.; Emsley, M. K.; Dosunmu, O. I.; Muller, P.; Leblebici, Y.

    2004-05-01

    Over the past decade a new family of optoelectronic devices has emerged whose performance is enhanced by placing the active device structure inside a Fabry-Perot resonant microcavity [P. E. Green, IEEE Spectrum 13 (2002)]. The increased optical field allows photodetectors to be made thinner and therefore faster, while simultaneously increasing the quantum efficiency at the resonant wavelengths. We have demonstrated a variety of resonant cavity enhanced (RCE) photodetectors in compound semiconductors [B. Yang, J. D. Schaub, S. M. Csutak, D. J. Rogers, and J. C. Campbell, IEEE Photonics Technol. Lett. 15, 745 (2003)] and Si [M. K. Emsley, O. I. Dosunmu, and M. S. Ünlü, IEEE J. Selected Topics Quantum Electron. 8, 948 (2002)], operating at optical communication wavelengths ranging from 850 nm to 1550 nm. The focus of this article is on Si photodetectors and arrays. 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 interchip 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, high speed, high efficiency silicon photodetectors present a technical challenge. Commercially reproducible silicon wafers with a high reflectance buried distributed Bragg reflector (DBR) have been designed and fabricated [M. K. Emsley, O. I. Dosunmu, and M. S. Ünlü, IEEE J. Selected Topics Quantum Electron. 8, 948 (2002)]. 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 850 nm and a FWHM of 29 ps suitable for 10 Gbps data

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

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  4. Coupled-resonator vertical-cavity lasers with two active gain regions

    DOEpatents

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

    2003-05-20

    A new class of coupled-resonator vertical-cavity semiconductor lasers has been developed. These lasers have multiple resonant cavities containing regions of active laser media, resulting in a multi-terminal laser component with a wide range of novel properties.

  5. Selective engineering of cavity resonance for frequency matching in optical parametric processes

    SciTech Connect

    Lu, Xiyuan; Rogers, Steven; Jiang, Wei C.; Lin, Qiang

    2014-10-13

    We propose to selectively engineer a single cavity resonance to achieve frequency matching for optical parametric processes in high-Q microresonators. For this purpose, we demonstrate an approach, selective mode splitting (SMS), to precisely shift a targeted cavity resonance, while leaving other cavity modes intact. We apply SMS to achieve efficient parametric generation via four-wave mixing in high-Q silicon microresonators. The proposed approach is of great potential for broad applications in integrated nonlinear photonics.

  6. Cavity-resonator-integrated guided-mode resonance band-stop reflector.

    PubMed

    Ura, Shogo; Nakata, Masahiro; Yanagida, Kenichi; Inoue, Junichi; Kintaka, Kenji

    2016-06-27

    A cavity-resonator-integrated guided-mode resonance filter (CRIGF) consists of a grating coupler inside a pair of distributed Bragg reflectors. A combination of a CRIGF with a high-reflection substrate can provide a new type of a band-stop reflector with a small aperture for a vertically incident wave from air. A narrow stopband was theoretically predicted and experimentally demonstrated. It was quantitatively shown that reflection spectra depended on optical-buffer-layer thickness. The reflector of 10-μm aperture was fabricated and characterized. The extinction ratio in reflectance was measured to be lower than -20 dB at a resonance wavelength. The bandwidth at -3 dB was 0.15 nm.

  7. Lithographic wavelength control of an external cavity laser with a silicon photonic crystal cavity-based resonant reflector.

    PubMed

    Liles, Alexandros A; Debnath, Kapil; O'Faolain, Liam

    2016-03-01

    We report the experimental demonstration of a new design for external cavity hybrid lasers consisting of a III-V semiconductor optical amplifier (SOA) with fiber reflector and a photonic crystal (PhC)-based resonant reflector on SOI. The silicon reflector is composed of an SU8 polymer bus waveguide vertically coupled to a PhC cavity and provides a wavelength-selective optical feedback to the laser cavity. This device exhibits milliwatt-level output power and side-mode suppression ratios of more than 25 dB.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Reflection-phase spectra of cavity-resonator-integrated guided-mode resonance devices

    NASA Astrophysics Data System (ADS)

    Inoue, Junichi; Okuda, Hiroki; Kintaka, Kenji; Nishio, Kenzo; Ura, Shogo

    2017-07-01

    A cavity-resonator-integrated guided-mode resonance filter (CRIGF) consisting of waveguide gratings on a transparent substrate can provide not only a narrowband reflection spectrum but also a steep reflection-phase spectrum. Reflection-phase spectra of CRIGFs were discussed in detail theoretically with an analytical expression. It was found that CRIGFs can be categorized into two types showing a phase variation of 2π rad, namely, reflection-phase rotation, or no rotation. On the other hand, the same structure on a high-reflection mirror, instead of the transparent substrate, normally shows the rotation. The two types of CRIGFs were designed and fabricated with different core thicknesses so that theoretically predicted reflection-phase characteristics with and without rotation could be demonstrated experimentally.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Popović, S.; Upadhyay, J.; Nikolić, M.; Vušković, L.; Mammosser, J.

    2014-11-07

    We are reporting experimental results on a 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 cryo-module. This discharge offers a 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 issues related to resonant detuning due to sustained multi-cell cavity plasma. 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.

  13. Detecting body cavity bombs with nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    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.

  14. Model-Based Feedback Control of Cavity Resonance: An Experimental and Computational Approach

    DTIC Science & Technology

    2006-07-24

    cavity flow control as well as for other closed-loop flow control applications. Theo - retical models are presented for temporally developing shear layers...smoothening. J. Sound Vib., 253(4):807-831, 2002. [52] L. S. Ukeiley, M. K. Ponton, J. S. Seiner, and B. Jansen . Suppression of pressure loads in cavity flows...AIAA Paper 2002-0661, 2002. [53] L. S. Ukeiley, M. K. Ponton, J. S. Seiner, and B. Jansen . Suppression of pressure loads in resonating cavities

  15. Theory of resonance fluorescence from a solid-state cavity QED system: Effects of pure dephasing

    SciTech Connect

    Koshino, Kazuki

    2011-09-15

    We theoretically analyze the resonance fluorescence of a solid-state cavity quantum electrodynamics (QED) system that consists of a quantum dot and a cavity. We clarify the effects of pure dephasing by investigating the elastic and inelastic scattering probabilities, the fluorescence power spectrum, and the energy exchange with the environment. Pure dephasing interactions with the environment both enhance nonresonant coupling between the dot and the cavity and enable the pump light to continuously absorb energy from the environment under appropriate conditions.

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

    PubMed

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

    2011-12-05

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

  17. Cavity Resonator Wireless Power Transfer System for Freely Moving Animal Experiments.

    PubMed

    Mei, Henry; Thackston, Kyle A; Bercich, Rebecca A; Jefferys, John G R; Irazoqui, Pedro P

    2017-04-01

    The goal of this paper is to create a large wireless powering arena for powering small devices implanted in freely behaving rodents. We design a cavity resonator based wireless power transfer (WPT) system and utilize our previously developed optimal impedance matching methodology to achieve effective WPT performance for operating sophisticated implantable devices, made with miniature receive coils (<8 mm in diameter), within a large volume (dimensions: 60.96 cm × 60.96 cm × 30 cm). We provide unique cavity design and construction methods which maintains electromagnetic performance of the cavity while promoting its utility as a large animal husbandry environment. In addition, we develop a biaxial receive resonator system to address device orientation insensitivity within the cavity environment. Functionality is demonstrated with chronic experiments involving rats implanted with our custom designed bioelectric recording device. We demonstrate an average powering fidelity of 93.53% over nine recording sessions across nine weeks, indicating nearly continuous device operation for a freely behaving rat within the large cavity resonator space. We have developed and demonstrated a cavity resonator based WPT system for long term experiments involving freely behaving small animals. This cavity resonator based WPT system offers an effective and simple method for wirelessly powering miniaturized devices implanted in freely moving small animals within the largest space.

  18. Cavity light bullets: three-dimensional localized structures in a nonlinear optical resonator.

    PubMed

    Brambilla, Massimo; Maggipinto, Tommaso; Patera, Giuseppe; Columbo, Lorenzo

    2004-11-12

    We consider the paraxial model for a nonlinear resonator with a saturable absorber beyond the mean-field limit. For accessible parametric domains we observe total radiation confinement and the formation of 3D localized bright structures. Different from freely propagating light bullets, here the self-organization proceeds from the resonator feedback, combined with diffraction and nonlinearity. Such "cavity" light bullets can be independently excited and erased by appropriate pulses, and once created, they endlessly travel the cavity round-trip.

  19. Realization of a double-barrier resonant tunneling diode for cavity polaritons.

    PubMed

    Nguyen, H S; Vishnevsky, D; Sturm, C; Tanese, D; Solnyshkov, D; Galopin, E; Lemaître, A; Sagnes, I; Amo, A; Malpuech, G; Bloch, J

    2013-06-07

    We report on the realization of a double-barrier resonant tunneling diode for cavity polaritons, by lateral patterning of a one-dimensional cavity. Sharp transmission resonances are demonstrated when sending a polariton flow onto the device. We show that a nonresonant beam can be used as an optical gate and can control the device transmission. Finally, we evidence distortion of the transmission profile when going to the high-density regime, signature of polariton-polariton interactions.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2000-11-01

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

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

    SciTech Connect

    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.

  3. Resonator modes and mode dynamics for an external cavity-coupled laser array

    NASA Astrophysics Data System (ADS)

    Nair, Niketh; Bochove, Erik J.; Aceves, Alejandro B.; Zunoubi, Mohammad R.; Braiman, Yehuda

    2015-03-01

    Employing a Fox-Li approach, we derived the cold-cavity mode structure and a coupled mode theory for a phased array of N single-transverse-mode active waveguides with feedback from an external cavity. We applied the analysis to a system with arbitrary laser lengths, external cavity design and coupling strengths to the external cavity. The entire system was treated as a single resonator. The effect of the external cavity was modeled by a set of boundary conditions expressed by an N-by-N frequency-dependent matrix relation between incident and reflected fields at the interface with the external cavity. The coupled mode theory can be adapted to various types of gain media and internal and external cavity designs.

  4. Frequency combs for cavity cascades: OPO combs and graphene-coupled cavities

    NASA Astrophysics Data System (ADS)

    Lee, Kevin F.; Kowzan, Grzegorz; Lee, C.-C.; Mohr, C.; Jiang, Jie; Schunemann, Peter G.; Schibli, T. R.; Maslowski, Piotr; Fermann, M. E.

    2017-01-01

    Frequency combs can be used directly, for example as a highly precise spectroscopic light source. They can also be used indirectly, as a bridge between devices whose high precision requirements would normally make them incompatible. Here, we demonstrate two ways that a frequency comb enables new technologies by matching optical cavities. One cavity is the laser oscillator. A second cavity is a low-threshold doubly-resonant optical parametric oscillator (OPO). Extending optical referencing to the doubly-resonant OPO turns the otherwise unstable device into an extremely precise midinfrared frequency comb. Another cavity is an optical enhancement cavity for amplifying spectral absorption in a gas. With the high speed of a graphene-modulated frequency comb, we can couple a frequency comb directly into a high-finesse cavity for trace gas detection.

  5. Experiment study of an electron cyclotron resonant ion source based on a tapered resonance cavity

    SciTech Connect

    Yang, Juan; Shi, Feng; Jin, Yizhou; Wang, Yunmin; Komurasaki, Kimiya

    2013-12-15

    Electron cyclotron resonant plasma is one type of magnetised plasma generated by continuous microwave energy. It has the property of high degree of ionization and large volume at low gas pressure, which makes it useful for space propulsion and material processing. This article presents the experiment study of the plasma properties and ion beam extraction from an electron cyclotron resonant ion source based on a tapered resonance cavity. Optical emission spectroscopy based on a simple collisional radiation model was used for plasma diagnosis. Experiment results show that, at microwave power setting ranging from 7.06 to 17.40 W and mass flow rate ranging from 1 to 10 sccm, argon gas can be ionized. Ion beam of 109.1 mA from the ion source can be extracted at microwave power of 30 W, mass flow rate of 10 sccm, and accel voltage of 800 V. The diagnosed plasma temperature and density are 2.4–5.2 eV and 2 × 10{sup 16}–4.8 × 10{sup 17} m{sup −3}, respectively.

  6. Application of extremum seeking for time-varying systems to resonance control of RF cavities

    SciTech Connect

    Scheinker, Alexander

    2016-09-13

    A recently developed form of extremum seeking for time-varying systems is implemented in hardware for the resonance control of radio-frequency cavities without phase measurements. Normal conducting RF cavity resonance control is performed via a slug tuner, while superconducting TESLA-type cavity resonance control is performed via piezo actuators. The controller maintains resonance by minimizing reflected power by utilizing model-independent adaptive feedback. Unlike standard phase-measurement-based resonance control, the presented approach is not sensitive to arbitrary phase shifts of the RF signals due to temperature-dependent cable length or phasemeasurement hardware changes. The phase independence of this method removes common slowly varying drifts and required periodic recalibration of phase-based methods. A general overview of the adaptive controller is presented along with the proof of principle experimental results at room temperature. Lastly, this method allows us to both maintain a cavity at a desired resonance frequency and also to dynamically modify its resonance frequency to track the unknown time-varying frequency of an RF source, thereby maintaining maximal cavity field strength, based only on power-level measurements.

  7. Application of extremum seeking for time-varying systems to resonance control of RF cavities

    DOE PAGES

    Scheinker, Alexander

    2016-09-13

    A recently developed form of extremum seeking for time-varying systems is implemented in hardware for the resonance control of radio-frequency cavities without phase measurements. Normal conducting RF cavity resonance control is performed via a slug tuner, while superconducting TESLA-type cavity resonance control is performed via piezo actuators. The controller maintains resonance by minimizing reflected power by utilizing model-independent adaptive feedback. Unlike standard phase-measurement-based resonance control, the presented approach is not sensitive to arbitrary phase shifts of the RF signals due to temperature-dependent cable length or phasemeasurement hardware changes. The phase independence of this method removes common slowly varying drifts andmore » required periodic recalibration of phase-based methods. A general overview of the adaptive controller is presented along with the proof of principle experimental results at room temperature. Lastly, this method allows us to both maintain a cavity at a desired resonance frequency and also to dynamically modify its resonance frequency to track the unknown time-varying frequency of an RF source, thereby maintaining maximal cavity field strength, based only on power-level measurements.« less

  8. Application of extremum seeking for time-varying systems to resonance control of RF cavities

    SciTech Connect

    Scheinker, Alexander

    2016-09-13

    A recently developed form of extremum seeking for time-varying systems is implemented in hardware for the resonance control of radio-frequency cavities without phase measurements. Normal conducting RF cavity resonance control is performed via a slug tuner, while superconducting TESLA-type cavity resonance control is performed via piezo actuators. The controller maintains resonance by minimizing reflected power by utilizing model-independent adaptive feedback. Unlike standard phase-measurement-based resonance control, the presented approach is not sensitive to arbitrary phase shifts of the RF signals due to temperature-dependent cable length or phasemeasurement hardware changes. The phase independence of this method removes common slowly varying drifts and required periodic recalibration of phase-based methods. A general overview of the adaptive controller is presented along with the proof of principle experimental results at room temperature. Lastly, this method allows us to both maintain a cavity at a desired resonance frequency and also to dynamically modify its resonance frequency to track the unknown time-varying frequency of an RF source, thereby maintaining maximal cavity field strength, based only on power-level measurements.

  9. Power enhancement of burst-mode UV pulses using a doubly-resonant optical cavity

    SciTech Connect

    Rahkman, Abdurahim; Notcutt, Mark; Liu, Yun

    2015-11-24

    We report a doubly-resonant enhancement cavity (DREC) that can realize a simultaneous enhancement of two incoming laser beams at different wavelengths and different temporal structures. The double-resonance condition is theoretically analyzed and different DREC locking methods are experimentally investigated. Simultaneous locking of a Fabry-Perot cavity to both an infrared (IR, 1064 nm) and its frequency tripled ultraviolet (UV, 355 nm) pulses has been demonstrated by controlling the frequency difference between the two beams with a fiber optic frequency shifter. The DREC technique opens a new paradigm in the applications of optical cavities to power enhancement of burst-mode lasers with arbitrary macropulse width and repetition rate.

  10. Power enhancement of burst-mode ultraviolet pulses using a doubly resonant optical cavity.

    PubMed

    Rakhman, Abdurahim; Notcutt, Mark; Liu, Yun

    2015-12-01

    We report a doubly resonant enhancement cavity (DREC) that can realize a simultaneous enhancement of two incoming laser beams at different wavelengths and different temporal structures. The double-resonance condition is theoretically analyzed, and different DREC locking methods are experimentally investigated. Simultaneous locking of a Fabry-Perot cavity to both an infrared (1064 nm) and its frequency-tripled ultraviolet (355 nm) pulses has been demonstrated by controlling the frequency difference between the two beams with a fiber-optic frequency shifter. The DREC technique enables novel applications of optical cavities to power enhancement of burst-mode lasers with arbitrary macropulse width and repetition rate.

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

    PubMed

    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.

  12. Resonant mode characterisation of a cylindrical Helmholtz cavity excited by a shear layer.

    PubMed

    Bennett, Gareth J; Stephens, David B; Rodriguez Verdugo, Francisco

    2017-01-01

    This paper investigates the interaction between the shear-layer over a circular cavity with a relatively small opening and the flow-excited acoustic response of the volume within to shear-layer instability modes. Within the fluid-resonant category of cavity oscillation, most research has been conducted on rectangular geometries: generally restricted to longitudinal standing waves, or when cylindrical: to Helmholtz resonance. In practical situations, however, where the cavity is subject to a range of flow speeds, many different resonant mode types may be excited. The current work presents a cylindrical cavity design where Helmholtz oscillation, longitudinal resonance, and azimuthal acoustic modes may all be excited upon varying the flow speed. Experiments performed show how lock-on between each of the three fluid-resonances and shear-layer instability modes can be generated. A circumferential array of microphones flush-mounted with the internal surface of the cavity wall was used to decompose the acoustic pressure field into acoustic modes and has verified the excitation of higher order azimuthal modes by the shear-layer. For azimuthal modes especially, the location of the cavity opening affects the pressure response. A numerical solution is validated and provides additional insight and will be applied to more complex aeronautical and automotive geometries in the future.

  13. High precision redundant robotic manipulator

    DOEpatents

    Young, Kar-Keung David

    1998-01-01

    A high precision redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degreed of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute point per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end point repeatability of less than 10 microns.

  14. High precision redundant robotic manipulator

    DOEpatents

    Young, K.K.D.

    1998-09-22

    A high precision redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space is disclosed. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degrees of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute point per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end point repeatability of less than 10 microns. 3 figs.

  15. Cavity enhanced ultra-thin aluminum plasmonic resonator for surface enhanced infrared absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Jiang, Xiao; Nong, Jinpeng; Chen, Na; Lan, Guilian; Tang, Linlong

    2016-11-01

    Owing to the advantages of natural abundance, low cost, and amenability to manufacturing processes, aluminum has recently been recognized as a highly promising plasmonic material that attracts extensive research interest. Here, we propose a cavity-enhanced ultra-thin plasmonic resonator for surface enhanced infrared absorption spectroscopy. The considered resonator consists of a patterned ultra-thin aluminum grating strips, a dielectric spacer layer and a reflective layer. In such structure, the resonance absorption is enhanced by the cavity formed between the patterned aluminum strips and the reflective layer. It is demonstrated that the spectral features of the resonator can be tuned by adjusting the structural parameters. Furthermore, in order to achieve a deep and broad spectral line shape, the spacer layer thickness should be properly designed to realize the simultaneous resonances for the electric and the magnetic excitations. The enhanced infrared absorption characteristics can be used for infrared sensing of the environment. When the resonator is covered with a molecular layer, the resonator can be used as a surface enhanced infrared absorption substrate to enhance the absorption signal of the molecules. A high enhanced factor of 1.15×105 can be achieved when the resonance wavelength of resonator is adjusted to match the desired vibrational mode of the molecules. Such a cavity-enhanced plasmonic resonator, which is easy for practical fabrication, is expected to have potential applications for infrared sensing with high-performance.

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

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

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

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

    NASA Astrophysics Data System (ADS)

    Dolatabady, Alireza; Granpayeh, Nosrat

    2017-04-01

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

  18. Nonlinear frequency mixing in a resonant cavity: numerical simulations in a bubbly liquid.

    PubMed

    Vanhille, Christian; Campos-Pozuelo, Cleofé; Sinha, Dipen N

    2014-12-01

    The study of nonlinear frequency mixing for acoustic standing waves in a resonator cavity is presented. Two high frequencies are mixed in a highly nonlinear bubbly liquid filled cavity that is resonant at the difference frequency. The analysis is carried out through numerical experiments, and both linear and nonlinear regimes are compared. The results show highly efficient generation of the difference frequency at high excitation amplitude. The large acoustic nonlinearity of the bubbly liquid that is responsible for the strong difference-frequency resonance also induces significant enhancement of the parametric frequency mixing effect to generate second harmonic of the difference frequency. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    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.

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

    PubMed Central

    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. Focused ion beam engineered whispering gallery mode resonators with open cavity structure.

    PubMed

    Aveline, David C; Baumgartel, Lukas; Ahn, Byungmin; Yu, Nan

    2012-07-30

    We report the realization of an open cavity whispering gallery mode optical resonator, in which the circulating light traverses a free space gap. We utilize focused ion beam microfabrication to precisely cut a 10 μm wide notch into the perimeter of a crystalline disc. We have shown that this modified resonator structure supports high quality modes, and demonstrated qualify factor, Q ~/= 10(6), limited by the notch surface roughness due to the ion milling process. Furthermore, we investigated the spatial profile of the modes inside the open cavity with a microfabricated probe mechanism. This new type of resonator structure facilitates interaction of the cavity's optical field with mechanical resonators as well as individual atoms or molecules.

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

    PubMed

    Octavio Manzanares, Alberto; Montero de Espinosa, Francisco

    2012-04-01

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

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

    NASA Astrophysics Data System (ADS)

    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. Raman-assisted Rabi resonances in two-mode cavity QED

    SciTech Connect

    Gruenwald, P.; Singh, S. K.; Vogel, W.

    2011-06-15

    The dynamics of a vibronic system in a lossy two-mode cavity is studied, with the first mode being resonant to the electronic transition and the second one being nearly resonant due to Raman transitions. We derive analytical solutions for the dynamics of this system. For a properly chosen detuning of the second mode from the exact Raman resonance, we obtain conditions that are closely related to the phenomenon of Rabi resonance as it is well known in laser physics. Such resonances can be observed in the spontaneous emission spectra, where the spectrum of the second mode in the case of weak Raman coupling is enhanced substantially.

  5. A Resonant Cavity Approach to Non-Invasive, Pulse-to-Pulse EmittanceMeasurement

    SciTech Connect

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

    2010-06-15

    We present a resonant cavity approach for non-invasive, pulse-to-pulse, beam emittance measurements of non-circular multi-bunch beams. In a resonant cavity, desired field components can be enhanced up to Q{sub L{lambda}}/{pi}, where Q{sub L{lambda}} is the loaded quality factor of the resonant mode {lambda}, when the cavity resonant mode matches the bunch frequency of a bunch-train beam pulse. In particular, a quad-cavity, with its quadrupole mode (TM{sub 220} for rectangular cavities) at beam operating frequency, rotated 45{sup o} with respect to the beamline, extracts the beam quadrupole moment exclusively, utilizing the symmetry of the cavity and some simple networks to suppress common modes. Six successive beam quadrupole moment measurements, performed at different betatron phases in a linear transport system determine the beam emittance, i.e. the beam size and shape in the beam's phase space, if the beam current and position at these points are known. In the presence of x-y beam coupling, ten measurements are required. One measurement alone provides the rms-beam size of a large aspect ratio beam. The resolution for such a measurement of rms-beam size with the rectangular quad-cavity monitor presented in this article is estimated to be on the order of ten microns. A prototype quad-cavity was fabricated and preliminary beam tests were performed at the Next Linear Collider Test Accelerator (NLCTA) at the Stanford Linear Accelerator Center (SLAC). Results were mainly limited by beam jitter and uncertainty in the beam position measurement at the cavity location. This motivated the development of a position-emittance integrated monitor.

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

    SciTech Connect

    Le Floch, J.-M. E-mail: jeanmichel.lefloch@uwa.edu.au; Delhote, N.; Aubourg, M.; Madrangeas, V.; Cros, D.; Castelletto, S.; Tobar, M. E.

    2016-04-21

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    Koval, L. R.

    1978-01-01

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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    Jurečka, Stanislav; Müllerová, Jarmila; Dado, Milan

    2011-09-01

    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.

  11. Passive control of flow-excited acoustic resonance in rectangular cavities using upstream mounted blocks

    NASA Astrophysics Data System (ADS)

    Shaaban, Mahmoud; Mohany, Atef

    2015-04-01

    A passive method for controlling the flow-excited acoustic resonance resulting from subsonic flows over rectangular cavities in channels is investigated. A cavity with length to depth ratio of is tested in air flow of Mach number up to 0.45. When the acoustic resonance is excited, the sound pressure level in the cavity reaches 162 dB. Square blocks are attached to the surface of the channel and centred upstream of the cavity leading edge to suppress the flow-excited acoustic resonance in the cavity. Six blocks of different widths are tested at three different upstream distances. The results show that significant attenuation of up to 30 dB of the excited sound pressure level is achieved using a block with a width to height ratio of 3, while blocks that fill the whole width of the channel amplify the pressure of the excited acoustic resonance. Moreover, it is found that placing the block upstream of the cavity causes the onset of the acoustic resonance to occur at higher flow velocities. In order to investigate the nature of the interactions that lead to suppression of the acoustic resonance and to identify the changes in flow patterns due to the placement of the block, 2D measurements of turbulence intensity in the shear layer and the block wake region are performed. The location of the flow reattachment point downstream of the block relative to the shear layer separation point has a major influence on the suppression level of the excited acoustic resonance. Furthermore, higher attenuation of noise is related to lower span-wise correlation of the shear-layer perturbation.

  12. Design of a terahertz parametric oscillator based on a resonant cavity in a terahertz waveguide

    SciTech Connect

    Saito, K. Oyama, Y.; Tanabe, T.

    2014-07-28

    We demonstrate ns-pulsed pumping of terahertz (THz) parametric oscillations in a quasi-triply resonant cavity in a THz waveguide. The THz waves, down converted through parametric interactions between the pump and signal waves at telecom frequencies, are confined to a GaP single mode ridge waveguide. By combining the THz waveguide with a quasi-triply resonant cavity, the nonlinear interactions can be enhanced. A low threshold pump intensity for parametric oscillations can be achieved in the cavity waveguide. The THz output power can be maximized by optimizing the quality factors of the cavity so that an optical to THz photon conversion efficiency, η{sub p}, of 0.35, which is near the quantum-limit level, can be attained. The proposed THz optical parametric oscillator can be utilized as an efficient and monochromatic THz source.

  13. Casimir-Polder potential and transition rate in resonating cylindrical cavities

    SciTech Connect

    Ellingsen, Simen A.; Buhmann, Stefan Yoshi; Scheel, Stefan

    2010-09-15

    We consider the Casimir-Polder potential of particles placed inside a metallic cylindrical cavity at finite temperatures, taking account of thermal nonequilibrium effects. In particular, we study how the resonant (thermal nonequilibrium) potential and transition rates can be enhanced by fine tuning the radius of the cavity to match the transition wavelength of the dominant transitions of the particle. Numerical calculations show that the cavity-induced energy-level shift of atoms prepared in low-lying Rydberg states can be enhanced beyond 30 kHz, which is within the range of observability of modern experiments. Because the magnitude of the resonance peaks depends sensitively on the low-frequency dissipation of the cavity metal, experiments in this setup could be a critical test of the disputed thermal correction to the Casimir force between metal plates.

  14. Resonant photodetector for cavity- and phase-locking of squeezed state generation

    NASA Astrophysics Data System (ADS)

    Chen, Chaoyong; Li, Zhixiu; Jin, Xiaoli; Zheng, Yaohui

    2016-10-01

    Based on the requirement of squeezed state generation, we build the phase relationship between two electronic local oscillators for the cavity- and phase-locking branches, and a 2-way 90° power splitter is adopted to satisfy the phase relationship simultaneously, which greatly simplifies the experimental setup and adjusting process. A LC parallel resonant circuit, which is composed by the inherent capacitance of a photodiode and an extra inductor, is adopted in the resonant photodetector to improve the gain factor at the expected frequency. The gain of the resonant photodetector is about 30 dB higher than that of the broadband photodetector at the resonant frequency. The peak-to-peak value of the error signal for cavity-locking (phase-locking) with the resonant photodetector is 240 (260) times of that with the broadband photodetector, which can improve the locking performance on the premise of not affecting the squeezing degree.

  15. Femtogram scale nanomechanical resonators embedded in a double-slot photonic crystal nanobeam cavity

    NASA Astrophysics Data System (ADS)

    Zhang, He; Zeng, Cheng; Chen, Daigao; Li, Miaofeng; Wang, Yi; Huang, Qingzhong; Xiao, Xi; Xia, Jinsong

    2016-02-01

    An optomechanical device that contains a nanomechanical resonator with an ultralow effective mass of 6.42 fg is designed and demonstrated. The femtogram scale nanomechanical resonator is embedded in a double-slot photonic crystal nanobeam cavity. Optical resonance provides efficient readout of the nanomechanical resonator movements. The fabricated device is optically and mechanically characterized in atmosphere. In the measured radio-frequency power spectral density, a peak at 3.928 GHz is identified to be the mechanical mode with an effective mass of 6.42 fg. The measured room-temperature mechanical Q-factor is 1255, and a displacement sensitivity of 0.13 fm/ √{ Hz } , which is 22 times beyond the standard quantum limit, is obtained. These demonstrated on-chip integrated optomechanical devices combining high Q-factor optical cavities and nanomechanical resonators with ultralow effective masses are promising in ultrasensitive measurements.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-09-01

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

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

    PubMed

    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.

  19. A new boundary integral approach to the determination of the resonant modes of arbitrary shaped cavities

    SciTech Connect

    Arcioni, P.; Bressan, M.; Perregrini, L.

    1995-08-01

    Computer codes for the electromagnetic analysis of arbitrarily shaped cavities are very important for many applications, in particular for the design of interaction structures for particle accelerators. The design of accelerating cavities results in complicated shapes, that are obtained carrying on repeated analyses to optimize a number of parameters, such as Q-factors, beam coupling impedances, higher-order-mode spectrum, and so on. The interest in the calculation of many normalized modes derives also from the important role they play in the eigenvector expansion of the electromagnetic field in a closed region. The authors present an efficient algorithm to determine the resonant frequencies and the normalized modal fields of arbitrarily shaped cavity resonators filled with a lossless, isotropic, and homogeneous medium. The algorithm is based on the boundary integral method (BIM). The unknown current flowing on the cavity wall is considered inside a spherical resonator, rather than in free-space, as it is usual in the standard BIM. The electric field is expressed using the Green`s function of the spherical resonator, approximated by a real rational function of the frequency. Consequently, the discretized problem can be cast into the form of a real matrix linear eigenvalue problem, whose eigenvalues and eigenvectors yield the resonant frequencies and the associated modal currents. Since the algorithm does not require any frequency-by-frequency recalculation of the system matrices, computing time is much shorter than in the standard BIM, especially when many resonances must be found.

  20. High Precision Rovibrational Spectroscopy of OH+

    NASA Astrophysics Data System (ADS)

    Markus, Charles R.; Hodges, James N.; Perry, Adam J.; Kocheril, G. Stephen; Müller, Holger S. P.; McCall, Benjamin J.

    2016-02-01

    The molecular ion OH+ has long been known to be an important component of the interstellar medium. Its relative abundance can be used to indirectly measure cosmic ray ionization rates of hydrogen, and it is the first intermediate in the interstellar formation of water. To date, only a limited number of pure rotational transitions have been observed in the laboratory making it necessary to indirectly calculate rotational levels from high-precision rovibrational spectroscopy. We have remeasured 30 transitions in the fundamental band with MHz-level precision, in order to enable the prediction of a THz spectrum of OH+. The ions were produced in a water cooled discharge of O2, H2, and He, and the rovibrational transitions were measured with the technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy. These values have been included in a global fit of field free data to a 3Σ- linear molecule effective Hamiltonian to determine improved spectroscopic parameters which were used to predict the pure rotational transition frequencies.

  1. High Precision Spectroscopy of Neutral Beryllium-9

    NASA Astrophysics Data System (ADS)

    Lau, Chui Yu; Williams, Will

    2015-05-01

    We report on the progress of high precision spectroscopy of the 2s2p singlet and triplet states in beryllium-9. Our goal is to improve the experimental precision on the energy levels of the 2s2p triplet J = 0, 1, and 2 states by a factor of 500, 100, and 500 respectively in order to delineate various theoretical predictions. The goal for the 2s2p singlet (J = 1) state is to improve the experimental precision on the energy level by a factor of 600 as a test of quantum electrodynamics. Our experimental setup consists of an oven capable of 1400 C that produces a collimated beam of neutral beryllium-9. The triplet states are probed with a 455 nm ECDL stabilized to a tellurium-210 line. The singlet state is probed with 235nm light from a frequency quadrupled titanium sapphire laser, where the frequency doubled light at 470 nm is stabilized to another tellurium-210 line. We also present our progress on improving the absolute accuracy of our frequency reference by using an ultrastable/low drift fiber coupled cavity.

  2. Analysis of two stacked cylindrical dielectric resonators in a TE₁₀₂ microwave cavity for magnetic resonance spectroscopy.

    PubMed

    Mattar, Saba M; Elnaggar, Sameh Y

    2011-04-01

    The frequency, field distributions and filling factors of a DR/TE₁₀₂ probe, consisting of two cylindrical dielectric resonators (DR1 and DR2) in a rectangular TE₁₀₂ cavity, are simulated and analyzed by finite element methods. The TE(+++) mode formed by the in-phase coupling of the TE₀₁(δ)(DR1), TE₀₁(δ)(DR2) and TE₁₀₂ basic modes, is the most appropriate mode for X-band EPR experiments. The corresponding simulated B(+++) fields of the TE(+++) mode have significant amplitudes at DR1, DR2 and the cavity's iris resulting in efficient coupling between the DR/TE₁₀₂ probe and the microwave bridge. At the experimental configuration, B(+++) in the vicinity of DR2 is much larger than that around DR1 indicating that DR1 mainly acts as a frequency tuner. In contrast to a simple microwave shield, the resonant cavity is an essential component of the probe that affects its frequency. The two dielectric resonators are always coupled and this is enhanced by the cavity. When DR1 and DR2 are close to the cavity walls, the TE(+++) frequency and B(+++) distribution are very similar to that of the empty TE₁₀₂ cavity. When all the experimental details are taken into account, the agreement between the experimental and simulated TE(+++) frequencies is excellent. This confirms that the resonating mode of the spectrometer's DR/TE₁₀₂ probe is the TE(+++) mode. Additional proof is obtained from B₁(x), which is the calculated maximum x component of B(+++). It is predominantly due to DR2 and is approximately 4.4 G. The B₁(x) maximum value of the DR/TE₁₀₂ probe is found to be slightly larger than that for a single resonator in a cavity because DR1 further concentrates the cavity's magnetic field along its x axis. Even though DR1 slightly enhances the performance of the DR/TE₁₀₂ probe its main benefit is to act as a frequency tuner. A waveguide iris can be used to over-couple the DR/TE₁₀₂ probe and lower its Q to ≈150. Under

  3. Design and simulation of resonant cavity enhanced corrugated quantum well infrared photodetectors.

    PubMed

    Kim, Jang Pyo; Sarangan, Andrew M

    2006-08-20

    The dipole selection rule limits the maximum achievable efficiency in corrugated quantum well infrared photodetectors (C-QWIPs) to 50%. We consider what is believed to be a novel design that utilizes a resonant cavity enhancement technique to increase the efficiency beyond 50% by rotating the photon polarization at each pass around the cavity. Simulation results show that the quantum efficiency of this device can be enhanced up to 38% compared to that of the standard C-QWIP device.

  4. Investigation of higher spanwise Helmholtz resonance modes in slender covered cavities.

    PubMed

    de Jong, A T; Bijl, H

    2010-10-01

    Cavity aeroacoustic noise is relevant for aerospace and automotive industries and widely investigated since the 1950s. Most investigations so far consider cavities where opening length and width are of similar scale. The present investigation focuses on a less investigated setup, namely cavities that resemble the door gaps of automobiles. These cavities are both slender (width much greater than length or depth) and partially covered. Furthermore they are under influence of a low Mach number flow with a relatively thick boundary layer. Under certain conditions, these gaps can produce tonal noise. The present investigation attempts to reveal the aeroacoustic mechanism of this tonal noise for higher resonance modes. Experiments have been conducted on a simplified geometry, where unsteady internal pressures have been measured at different spanwise locations. With increasing velocity, several resonance modes occur. In order to obtain higher mode shapes, the cavity acoustic response is simulated and compared with experiment. Using the frequency-filtered simulation pressure field, the higher modes shapes are retrieved. The mode shapes can be interpreted as the slender cavity self-organizing into separate Helmholtz resonators that interact with each other. Based on this, an analytical model is derived that shows good agreement with the simulations and experimental results.

  5. Enhanced Entanglement Between Two Mechanical Resonators in Two Optomechanical Cavities with an Atomic Medium

    NASA Astrophysics Data System (ADS)

    Wu, E.; Li, DanYang; Li, FengZhi; Ma, YongHong

    2017-02-01

    We propose a theoretical method to enhance the entanglement between two mechanical resonators in two optomechanical cavities, which are coupled by the photon-hopping process, and each opto-mechanical cavity are consisted of a Fabry-Perot cavity and a mechanical oscillator by applying N atomic medium. We explore the effect of the entanglement between two mechanical oscillators with two atomic mediums and without them, respectively. The results show that the introduction of atoms can effectively increase the entanglement between the two oscillator modes.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Free-electron laser as a driver for a resonant cavity at 35 GHz

    PubMed

    Lefevre; Gardelle; Rullier; Vermare; Donohue; Meurdesoif; Lidia

    2000-02-07

    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.

  8. Resonance Cavities in Parallel-Hetero Perturbation Photonic Crystal Waveguide Structures

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Li, Zhi-Yuan

    2012-07-01

    We design a series of W1 waveguide-like parallel-hetero cavities (PHCs) made from the combination of parallelhetero perturbation (PHP) waveguides and photonic crystal waveguides and investigate their optical properties. Spectral properties are calculated numerically using the three-dimensional finite-difierence time-domain method. The resonant frequencies and quality factors are obtained for each type of PHC and comparisons are made among different types of PHC, which is helpful for predicting and understanding the properties of PHC and designing PHC based high-performance cavities. The PHCs can broaden the category of cavity design and find interesting applications in integrated optical devices and solid state lasers.

  9. Drude weight, cyclotron resonance, and the Dicke model of graphene cavity QED.

    PubMed

    Chirolli, Luca; Polini, Marco; Giovannetti, Vittorio; MacDonald, Allan H

    2012-12-28

    The unique optoelectronic properties of graphene make this two-dimensional material an ideal platform for fundamental studies of cavity quantum electrodynamics in the strong-coupling regime. The celebrated Dicke model of cavity quantum electrodynamics can be approximately realized in this material when the cyclotron transition of its 2D massless Dirac fermion carriers is nearly resonant with a cavity photon mode. We develop the theory of strong matter-photon coupling in this circumstance, emphasizing the essential role of a dynamically generated matter energy term that is quadratic in the photon field and absent in graphene's low-energy Dirac model.

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

    PubMed

    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

  11. Enhanced electromechanical coupling of a nanomechanical resonator to coupled superconducting cavities

    PubMed Central

    Li, Peng-Bo; Li, Hong-Rong; Li, Fu-Li

    2016-01-01

    We investigate the electromechanical coupling between a nanomechanical resonator and two parametrically coupled superconducting coplanar waveguide cavities that are driven by a two-mode squeezed microwave source. We show that, with the selective coupling of the resonator to the cavity Bogoliubov modes, the radiation-pressure type coupling can be greatly enhanced by several orders of magnitude, enabling the single photon strong coupling to be reached. This allows the investigation of a number of interesting phenomena such as photon blockade effects and the generation of nonclassical quantum states with electromechanical systems. PMID:26753744

  12. Enhanced electromechanical coupling of a nanomechanical resonator to coupled superconducting cavities.

    PubMed

    Li, Peng-Bo; Li, Hong-Rong; Li, Fu-Li

    2016-01-12

    We investigate the electromechanical coupling between a nanomechanical resonator and two parametrically coupled superconducting coplanar waveguide cavities that are driven by a two-mode squeezed microwave source. We show that, with the selective coupling of the resonator to the cavity Bogoliubov modes, the radiation-pressure type coupling can be greatly enhanced by several orders of magnitude, enabling the single photon strong coupling to be reached. This allows the investigation of a number of interesting phenomena such as photon blockade effects and the generation of nonclassical quantum states with electromechanical systems.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

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

  15. Large-Volume Resonant Microwave Discharge for Plasma Cleaning of a CEBAF 5-Cell SRF Cavity

    SciTech Connect

    J. Mammosser, S. Ahmed, K. Macha, J. Upadhyay, M. Nikoli, S. Popovi, L. Vuakovi

    2012-07-01

    We report the preliminary results on plasma generation in a 5-cell CEBAF superconducting radio-frequency (SRF) cavity for the application of cavity interior surface cleaning. CEBAF currently has {approx}300 of these five cell cavities installed in the Jefferson Lab accelerator which are mostly limited by cavity surface contamination. The development of an in-situ cavity surface cleaning method utilizing a resonant microwave discharge could lead to significant CEBAF accelerator performance improvement. This microwave discharge is currently being used for the development of a set of plasma cleaning procedures targeted to the removal of various organic, metal and metal oxide impurities. These contaminants are responsible for the increase of surface resistance and the reduction of RF performance in installed cavities. The CEBAF five cell cavity volume is {approx} 0.5 m2, which places the discharge in the category of large-volume plasmas. CEBAF cavity has a cylindrical symmetry, but its elliptical shape and transversal power coupling makes it an unusual plasma application, which requires special consideration of microwave breakdown. Our preliminary study includes microwave breakdown and optical spectroscopy, which was used to define the operating pressure range and the rate of removal of organic impurities.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  18. Cavity Self-Stabilization and Enhancement of Laser Gyroscopes by (Coupled) Optical Resonators

    NASA Technical Reports Server (NTRS)

    Smith, David D.

    2006-01-01

    We analyze the effect of a highly dispersive element placed inside a modulated optical cavity on the frequency and amplitude of the modulation to determine the conditions for cavity self-stabilization and enhanced gyroscopic sensitivity. Hence, we model cavity rotation or instability by an arbitrary AM/FM modulation, and the dispersive element as a phase and amplitude filter. We find that anomalous dispersion may be used to self-stabilize a laser cavity, provided the magnitude of the group index of refraction is smaller than the phase index of refraction in the cavity. The optimal stabilization is found to occur when the group index is zero. Group indices with magnitudes larger than the phase index (both normal and anomalous dispersion) are found to enhance the sensitivity of a laser gyroscope to rotation. Furthermore, our results indicate that atomic media, even coherent superpositions in multilevel atoms, are not useful for these applications, because the amplitude and phase filters work against one another, i.e., decreasing the modulation frequency increases its amplitude and vice versa, with one exception: negative group indices whose magnitudes are larger than the phase index result in negative, but enhanced, beat frequencies. On the other hand, for optical resonators the dispersion reversal associated with critical coupling enables the amplitude and phase filters to work together under a greater variety of circumstances than for atomic media. We find that for single over-coupled resonators, or in the case of under-coupled coupled-resonator-induced absorption, the absorption and normal dispersion on-resonance increase the contrast and frequency of the beat-note, respectively, resulting in a substantial enhancement of the gyroscopic response. Moreover, for cavity self-stabilization, we propose the use of a variety of coupled-resonator induced transparency that is accompanied by anomalous dispersion.

  19. Efficient frequency generation in phoXonic cavities based on hollow whispering gallery mode resonators

    PubMed Central

    Farnesi, Daniele; Righini, Giancarlo; Nunzi Conti, Gualtiero; Soria, Silvia

    2017-01-01

    We report on nonlinear optical effects on phoxonic cavities based on hollow whispering gallery mode resonators pumped with a continuous wave laser. We observed stimulated scattering effects such as Brillouin and Raman, Kerr effects such as degenerated and non-degenerated four wave mixing, and dispersive wave generation. These effects happened concomitantly. Hollow resonators give rise to a very rich nonlinear scenario due to the coexistence of several family modes. PMID:28266641

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

    NASA Technical Reports Server (NTRS)

    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.

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

    SciTech Connect

    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.

  2. Directive metamaterial-based subwavelength resonant cavity antennas - Applications for beam steering

    NASA Astrophysics Data System (ADS)

    Ourir, Abdelwaheb; Burokur, Shah Nawaz; Yahiaoui, Riad; de Lustrac, André

    2009-06-01

    This article presents the use of composite resonant metamaterials for the design of highly directive subwavelength cavity antennas. These metamaterials, composed of planar metallic patterns periodically organized on dielectric substrates, exhibit frequency dispersive phase characteristics. Different models of metamaterial-based surfaces (metasurfaces), introducing a zero degree reflection phase shift to incident waves, are firstly studied where the bandwidth and operation frequency are predicted. These surfaces are then applied in a resonant Fabry-Perot type cavity and a ray optics analysis is used to design different models of ultra-compact high-gain microstrip printed antennas. Another surface presenting a variable reflection phase by the use of a non-periodic metamaterial-based metallic strips array is designed for a passive low-profile steering beam antenna application. Finally, the incorporation of active electronic components on the metasurfaces, allowing an electronic control of the phase responses, is applied to an operation frequency reconfigurable cavity and a beam steering cavity. All these cavity antennas operate on subwavelength modes, the smallest cavity thickness being of the order of λ/60. To cite this article: A. Ourir et al., C. R. Physique 10 (2009).

  3. Power enhancement of burst-mode UV pulses using a doubly-resonant optical cavity

    DOE PAGES

    Rahkman, Abdurahim; Notcutt, Mark; Liu, Yun

    2015-11-24

    We report a doubly-resonant enhancement cavity (DREC) that can realize a simultaneous enhancement of two incoming laser beams at different wavelengths and different temporal structures. The double-resonance condition is theoretically analyzed and different DREC locking methods are experimentally investigated. Simultaneous locking of a Fabry-Perot cavity to both an infrared (IR, 1064 nm) and its frequency tripled ultraviolet (UV, 355 nm) pulses has been demonstrated by controlling the frequency difference between the two beams with a fiber optic frequency shifter. The DREC technique opens a new paradigm in the applications of optical cavities to power enhancement of burst-mode lasers with arbitrarymore » macropulse width and repetition rate.« less

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

    PubMed

    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.

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

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. A study of tyre cavity resonance and noise reduction using inner trim

    NASA Astrophysics Data System (ADS)

    Mohamed, Zamri; Wang, Xu

    2015-01-01

    A study of tyre inner trim as a method for reducing tyre cavity resonance noise is presented. The tyre is modelled as a rectangular toroid where only the outside shell is flexible. A modal series solution of the sound pressure frequency response inside the tyre cavity is derived from the wave equation using modal superposition. In the solution with the rigid and flexible wall boundary condition, the effect of placing a trim layer onto the inner surface of the tyre tread plate wall is reflected by adding a damping loss term in the sound pressure frequency response function. The numerical simulation result was then compared with the result obtained from a roving impact test performed on a tyre. The results show that selective trim material may be effective for reducing the structure-borne noise magnitude resulting from the tyre cavity resonance.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Demonstration of the stabilization technique for nonplanar optical resonant cavities utilizing polarization

    SciTech Connect

    Akagi, T.; Araki, S.; Funahashi, Y.; Honda, Y.; Okugi, T.; Omori, T.; Shimizu, H.; Terunuma, N.; Urakawa, J.; Miyoshi, S.; Takahashi, T. Tanaka, R.; Uesugi, Y.; Yoshitama, H.; Sakaue, K.; Washio, M.

    2015-04-15

    Based on our previously developed scheme to stabilize nonplanar optical resonant cavities utilizing polarization caused by a geometric phase in electromagnetic waves traveling along a twisted path, we report an application of the technique for a cavity installed in the Accelerator Test Facility, a 1.3-GeV electron beam accelerator at KEK, in which photons are generated by laser-Compton scattering. We successfully achieved a power enhancement of 1200 with 1.4% fluctuation, which means that the optical path length of the cavity has been controlled with a precision of 14 pm under an accelerator environment. In addition, polarization switching utilizing a geometric phase of the nonplanar cavity was demonstrated.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    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}.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Technical Reports Server (NTRS)

    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.

  14. Increasing the pumping efficiency of a resonant microwave stroage cavity

    NASA Astrophysics Data System (ADS)

    Baraev, S. V.; Korovin, O. P.

    1980-11-01

    A theoretical analysis shows that it is possible to improve the efficiency of pumping of a microwave-energy accumulation system by the use of a resonant accumulator whose coefficient of coupling, beta, with the transmission line significantly exceeds unity. It is found that for beta = 10 the maximum efficiency of pumping is 0.75; for beta = 100, the maximum efficiency attains the limiting value of 0.82. The accumulation time corresponding to the maximum pumping efficiency is of the order of 0.001-0.1 sec, and a pulse power increase of 50-75 dB is attained compared to pumping oscillator power.

  15. Resonance-free optical response of a vertical cavity transistor laser

    NASA Astrophysics Data System (ADS)

    Feng, M.; Wu, Cheng-Han; Wu, M. K.; Wu, Chao-Hsin; Holonyak, N.

    2017-09-01

    Optical resonance in a semiconductor laser is a major limitation in high speed data communications, resulting in bit error rate degradation and requiring additional power consuming error-correction circuits to counter these effects. In this work, we report the microwave bandwidth measurement of a vertical cavity transistor laser with an oxide-confined aperture of 4.7 × 5.4 μm2 and demonstrate a 3 dB bandwidth of 11 GHz resonance-free optical response via base-current or collector-voltage modulation. The emission spectra exhibit single-mode operation around 970 nm with a narrow linewidth of Δλ ˜ 0.23 Å (cavity Q of 42 216). The resonance-free optical response is explained by the absence of carrier "accumulating" due to the fast base electron-hole recombination lifetimes and a gradient in the minority carrier charge in the transistor active mode.

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

    PubMed Central

    Zhang, Xiangao; Shao, Mingzhen; Zeng, Xiaoqi

    2016-01-01

    In this paper, a type of compact nanosensor based on a metal-insulator-metal structure is proposed and investigated through cascading double asymmetric cavities, in which their metal cores shift along different axis directions. The cascaded asymmetric structure exhibits high transmission and sharp Fano resonance peaks via strengthening the mutual coupling of the cavities. The research results show that with the increase of the symmetry breaking in the structure, the number of Fano resonances increase accordingly. Furthermore, by modulating the geometrical parameters appropriately, Fano resonances with high sensitivities to the changes in refractive index can be realized. A maximum figure of merit (FoM) value of 74.3 is obtained. Considerable applications for this work can be found in bio/chemical sensors with excellent performance and other nanophotonic integrated circuit devices such as optical filters, switches and modulators. PMID:27763539

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Compact cavity design in solid state resonators by way of volume Bragg gratings

    NASA Astrophysics Data System (ADS)

    Anderson, B.; Venus, G.; Ott, D.; Divliansky, I.; Glebov, L.

    2014-02-01

    Volume Bragg gratings (VBG) recorded in photo-thermo refractive glass (PTR) have high stability, and high damage threshold, allowing for many applications to the design of high power lasers. Gratings recorded in the transmitting geometry (TBG) have narrow angular selectivity, and can be used as a spatial filter in a resonator. Such gratings have previously been useful for improving the brightness of high power diodes, and increasing the beam quality in rod geometry solid state lasers. As the gratings have narrow angular selectivity, losses for higher order modes in the resonator no longer depend on the cavity length, allowing for the construction of short cavities with large mode areas. In this paper, we explore the design of short 1cm cavities using two TBGs as a spatial filter and no aperture in the cavity. The M2 parameter as a function of pump size and angular selectivity of the TBG are explored, using pump diameters ranging from 800um to 2mm and angular selectivity ranging from 11mrad to 1.8mrad. An M2 parameter of 1.05 is reported for an 800μm pump diameter, a 6.2mrad TBG, and a 1cm long cavity.

  19. Monolithically integrated vertical-cavity lasers and resonant detectors for free-space optical interconnects

    NASA Astrophysics Data System (ADS)

    Louderback, Duane Alan

    In this dissertation, a new technique for integrating vertical cavity lasers and resonant-cavity photodetectors for free-space optical interconnects is explored. The work starts with an overview of the device requirements for free-space optical interconnects, specifically the need for integrated VCLs and detectors that are compatible with flip-chip bonding and microlens integration. The lack of a suitable integration technique lead to the development of a new method of integrating VCLs and detectors. Part of the VCL bottom mirror is oxidized, while the detector structure is left unoxidized, enabling different bottom mirror reflectivities to be achieved. This difference in bottom mirror reflectivity allows individually designed VCLs and resonant-cavity detectors to be monolithically integrated. Since the reflectivity difference is realized in the bottom mirror, the devices have through-the substrate emission and detection, making flip-chip bonding and microlens integration straightforward. High performance VCLs and resonant-cavity detectors were fabricated using this integration technique. A comprehensive analysis of the devices is performed with the goal of broadening the detector optical bandwidth without causing adverse effects on other device parameters. DC and high-speed device characteristics are presented, including the results of a free-space optical link where the operating temperature of the VCL and detector were independently varied over a wide range. These results demonstrate the potential of this integration technique for meeting the device requirements of free-space optical interconnect systems.

  20. Disk patch resonators for cavity quantum electrodynamics at the terahertz frequency.

    PubMed

    Derntl, Christian G; Bachmann, Dominic; Unterrainer, Karl; Darmo, Juraj

    2017-05-29

    We designed disk patch resonators to meet the requirements for enhanced coupling of optical cavities to intersubband transitions in heterostructures in the terahertz frequency regime. We applied modifications to the standard patch resonator in the form of a chain of holes and slits to control the resonator eigenmodes featuring quality factors ωFWHM/ω0 as high as 40. Due to the broken rotational symmetry of the resonators the individual eigenmodes can be accessed selectively depending on the incidence and the polarization of the THz wave. The demonstrated post-process blue-shifting of the resonance frequency up to 50% is a key tuning knob for an optimization of light-matter interaction in a quantum system.

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

    DTIC Science & Technology

    2013-09-01

    Reduction in Depth for a Radiating Flange Backed by a Rectangular Resonant Cavity Using High Index Materials: Preliminary Report by Gregory...Laboratory Adelphi, MD 20783-1197 ARL-MR-0851 September 2013 Reduction in Depth for a Radiating Flange Backed by a Rectangular Resonant ...SUBTITLE Reduction in Depth for a Radiating Flange Backed by a Rectangular Resonant Cavity Using High Index Materials: Preliminary Report 5a. CONTRACT

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

    NASA Astrophysics Data System (ADS)

    Zhou, Jinli; Chen, Huibin; Zhang, Zhidong; Tang, Jun; Cui, Jiangong; Xue, Chenyang; Yan, Shubin

    2017-01-01

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

  3. Note: High precision measurements using high frequency gigahertz signals

    NASA Astrophysics Data System (ADS)

    Jin, Aohan; Fu, Siyuan; Sakurai, Atsunori; Liu, Liang; Edman, Fredrik; Pullerits, Tõnu; Öwall, Viktor; Karki, Khadga Jung

    2014-12-01

    Generalized lock-in amplifiers use digital cavities with Q-factors as high as 5 × 108 to measure signals with very high precision. In this Note, we show that generalized lock-in amplifiers can be used to analyze microwave (giga-hertz) signals with a precision of few tens of hertz. We propose that the physical changes in the medium of propagation can be measured precisely by the ultra-high precision measurement of the signal. We provide evidence to our proposition by verifying the Newton's law of cooling by measuring the effect of change in temperature on the phase and amplitude of the signals propagating through two calibrated cables. The technique could be used to precisely measure different physical properties of the propagation medium, for example, the change in length, resistance, etc. Real time implementation of the technique can open up new methodologies of in situ virtual metrology in material design.

  4. Note: High precision measurements using high frequency gigahertz signals.

    PubMed

    Jin, Aohan; Fu, Siyuan; Sakurai, Atsunori; Liu, Liang; Edman, Fredrik; Pullerits, Tõnu; Öwall, Viktor; Karki, Khadga Jung

    2014-12-01

    Generalized lock-in amplifiers use digital cavities with Q-factors as high as 5 × 10(8) to measure signals with very high precision. In this Note, we show that generalized lock-in amplifiers can be used to analyze microwave (giga-hertz) signals with a precision of few tens of hertz. We propose that the physical changes in the medium of propagation can be measured precisely by the ultra-high precision measurement of the signal. We provide evidence to our proposition by verifying the Newton's law of cooling by measuring the effect of change in temperature on the phase and amplitude of the signals propagating through two calibrated cables. The technique could be used to precisely measure different physical properties of the propagation medium, for example, the change in length, resistance, etc. Real time implementation of the technique can open up new methodologies of in situ virtual metrology in material design.

  5. A NEW CONCEPT FOR HIGH POWER RF COUPLING BETWEEN WAVEGUIDES AND RESONANT RF CAVITIES

    DOE PAGES

    Xu, Chen; Ben-Zvi, Ilan; Wang, Haipeng; ...

    2017-01-01

    Microwave engineering of high average-power (hundreds of kilowatts) devices often involves a transition from a waveguide to a device, typically a resonant cavity. This is a basic operation, which finds use in various application areas of significance to science and industry. At relatively low frequencies, L-band and below, it is convenient, sometimes essential, to couple the power between the waveguide and the cavity through a coaxial antenna, forming a power coupler. Power flow to the cavity in the fundamental mode leads to a Fundamental Power Coupler (FPC). High-order mode power generated in the cavity by a particle beam leads tomore » a high-order mode power damper. Coupling a cryogenic device, such as a superconducting cavity to a room temperature power source (or damp) leads to additional constraints and challenges. We propose a new approach to this problem, wherein the coax line element is operated in a TE11 mode rather than the conventional TEM mode. We will show that this method leads to a significant increase in the power handling capability of the coupler as well as a few other advantages. As a result, we describe the mode converter from the waveguide to the TE11 coax line, outline the characteristics and performance limits of the coupler and provide a detailed worked out example in the challenging area of coupling to a superconducting accelerator cavity.« less

  6. A NEW CONCEPT FOR HIGH POWER RF COUPLING BETWEEN WAVEGUIDES AND RESONANT RF CAVITIES

    SciTech Connect

    Xu, Chen; Ben-Zvi, Ilan; Wang, Haipeng; Xin, Tianmu; Xiao, Liling

    2017-01-01

    Microwave engineering of high average-power (hundreds of kilowatts) devices often involves a transition from a waveguide to a device, typically a resonant cavity. This is a basic operation, which finds use in various application areas of significance to science and industry. At relatively low frequencies, L-band and below, it is convenient, sometimes essential, to couple the power between the waveguide and the cavity through a coaxial antenna, forming a power coupler. Power flow to the cavity in the fundamental mode leads to a Fundamental Power Coupler (FPC). High-order mode power generated in the cavity by a particle beam leads to a high-order mode power damper. Coupling a cryogenic device, such as a superconducting cavity to a room temperature power source (or damp) leads to additional constraints and challenges. We propose a new approach to this problem, wherein the coax line element is operated in a TE11 mode rather than the conventional TEM mode. We will show that this method leads to a significant increase in the power handling capability of the coupler as well as a few other advantages. As a result, we describe the mode converter from the waveguide to the TE11 coax line, outline the characteristics and performance limits of the coupler and provide a detailed worked out example in the challenging area of coupling to a superconducting accelerator cavity.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Microwave Resonant Cavity and Loaded Carbon Nanotubes -- A Sensor to Detect Toxins like Methamphetamine

    NASA Astrophysics Data System (ADS)

    Anand, Aman; Robert, James; Henley, Don; Dahiya, Jai

    2006-10-01

    A resonant cavity operating in TM010 mode was used to study the absorption response of Single Walled Carbon Nanotubes and other Nanomaterials for different types of gas molecules. The range of the frequency signal as a probe was chosen arbitrarily between 9.1 -9.8 GHz. A highly specific range will be studied for further experiments. It was found that for different pressures of different gases and different types of Nanomaterials, there was a different response in the shifts of the probe signal for each cycle of gassing and degassing of the cavity. The preliminary work done so far suggests that Microwave spectroscopy of the complex medium of gases and Carbon Nanotubes can be used as a highly sensitive technique in studying the complex dielectric response of different polar as well as non-polar gases when subjected to intense electromagnetic fields within the Cavity.

  10. A deterministic and statistical energy analysis of tyre cavity resonance noise

    NASA Astrophysics Data System (ADS)

    Mohamed, Zamri; Wang, Xu

    2016-03-01

    Tyre cavity resonance was studied using a combination of deterministic analysis and statistical energy analysis where its deterministic part was implemented using the impedance compact mobility matrix method and its statistical part was done by the statistical energy analysis method. While the impedance compact mobility matrix method can offer a deterministic solution to the cavity pressure response and the compliant wall vibration velocity response in the low frequency range, the statistical energy analysis method can offer a statistical solution of the responses in the high frequency range. In the mid frequency range, a combination of the statistical energy analysis and deterministic analysis methods can identify system coupling characteristics. Both methods have been compared to those from commercial softwares in order to validate the results. The combined analysis result has been verified by the measurement result from a tyre-cavity physical model. The analysis method developed in this study can be applied to other similar toroidal shape structural-acoustic systems.

  11. An ac method for the precise measurement of Q-factor and resonance frequency of a microwave cavity

    NASA Astrophysics Data System (ADS)

    Nebendahl, B.; Peligrad, D.-N.; Požek, M.; Dulčić, A.; Mehring, M.

    2001-03-01

    We have developed a new and fast method for the determination of the complex frequency shift of a microwave resonant cavity. The method is based on frequency modulation of the microwave source around the cavity resonance and detection of the 2nd and 4th harmonic of the modulation frequency. With this procedure the static measurement of the response amplitude is not necessary and all the data are obtained through a single ac channel. The optimal frequency deviation is shown to be comparable to the cavity resonance width.

  12. Phonon-mediated squeezing of the cavity field off-resonantly coupled with a coherently driven quantum dot

    SciTech Connect

    Zhu, Jia-pei; Huang, Hui; Li, Gao-xiang

    2014-01-21

    We theoretically propose a scheme for the quadrature squeezing of the cavity field via dissipative processes. The effects of the electron-phonon interaction (EPI) on the squeezing are investigated, where the cavity is off-resonantly coupled with a coherently driven quantum dot (QD) which is allowed to interact with an acoustic-phonon reservoir. Under certain conditions, the participation of the phonon induced by both the EPI and the off-resonant coupling of the cavity with the QD enables some dissipative processes to occur resonantly in the dressed-state basis of the QD. The cavity-mode photons emitted or absorbed during the phonon-mediated dissipative processes are correlated, thus leading to the squeezing of the cavity field. A squeezed vacuum reservoir for the cavity field is built up due to the EPI plus the off-resonant coupling between the cavity and the QD. The numerical results obtained with an effective polaron master equation derived using second-order perturbation theory indicate that, in low temperature limit, the degree of squeezing is maximal but the increasing temperature of the phonon reservoir could hinder the squeezing and degrade the degree of the squeezing of the cavity field. In addition, the presence of the photonic crystal could enhance the quadrature squeezing of the cavity field.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. A new heating method with dielectric bolus using resonant cavity applicator for brain tumors.

    PubMed

    Iseki, Y; Kato, K; Nakane, K; Shindo, Y; Tsuchiya, K; Kubo, M; Takahashi, H; Uzuka, T; Fujii, Y

    2011-01-01

    In this paper, we discuss a new method of controlling heating location in the proposed resonant cavity applicator. A dielectric bolus was used to non-invasively treat brain tumors. We have already confirmed that our heating system using resonant cavity is useful to non-invasively heat brain tumors. In order to heat tumors occurring at various locations, it is necessary to control the heating area with our heating system. First, we presented the proposed heating method and a phantom model to calculate temperature distributions. The results of temperature distributions were discussed. Second, a 3-D human head model constructed from 2-D MRI images was presented. The results of specific absorption rate distributions were discussed. From these results, it was found that the proposed heating method was useful to non-invasively treat brain tumors.

  15. All-dielectric resonant cavity-enabled metals with broadband optical transparency

    NASA Astrophysics Data System (ADS)

    Liu, Zhengqi; Zhang, Houjiao; Liu, Xiaoshan; Pan, Pingping; Liu, Yi; Tang, Li; Liu, Guiqiang

    2017-06-01

    Metal films with broadband optical transparency are desirable in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and infrared detectors. As bare metal is opaque to light, this issue of transparency attracts great scientific interest. In this work, we proposed and demonstrated a feasible and universal approach for achieving broadband optical transparent (BOT) metals by utilizing all-dielectric resonant cavities. Resonant dielectrics provide optical cavity modes and couple strongly with the surface plasmons of the metal film, and therefore produce a broadband near-unity optical transparent window. The relative enhancement factor (EF) of light transmission exceeds 3400% in comparison with that of pure metal film. Moreover, the transparent metal motif can be realized by other common metals including gold (Au), silver (Ag) and copper (Cu). These optical features together with the fully retained electric and mechanical properties of a natural metal suggest that it will have wide applications in optoelectronic devices.

  16. Transition of lasing modes in polymeric opal photonic crystal resonating cavity.

    PubMed

    Shi, Lan-Ting; Zheng, Mei-Ling; Jin, Feng; Dong, Xian-Zi; Chen, Wei-Qiang; Zhao, Zhen-Sheng; Duan, Xuan-Ming

    2016-06-10

    We demonstrate the transition of lasing modes in the resonating cavity constructed by polystyrene opal photonic crystals and 7 wt. % tert-butyl Rhodamine B doped polymer film. Both single mode and multiple mode lasing emission are observed from the resonating cavity. The lasing threshold is determined to be 0.81  μJ/pulse for single mode lasing emission and 2.25  μJ/pulse for multiple mode lasing emission. The single mode lasing emission is attributed to photonic lasing resulting from the photonic bandgap effect of the opal photonic crystals, while the multiple mode lasing emission is assigned to random lasing due to the defects in the photonic crystals. The result would benefit the development of low threshold polymeric solid state photonic crystal lasers.

  17. Resonant-cavity light-emitting diodes: quantum noise and spatial emission characteristics

    NASA Astrophysics Data System (ADS)

    Birkner, R. H.; Kaiser, J.; Elsässer, W.; Jung, C.

    2004-12-01

    We demonstrate the interplay between the intensity noise and the spatial emission characteristics of resonant-cavity light-emitting diodes. First, we find that the total aperture intensity noise exhibits a sub-shot noise behavior in a quite large pumping regime. Second, we investigate the angular, spectral, and spatial emission characteristics of the devices by controlling the shape and width of the angular intensity distribution via temperature detuning of the quantum well wavelength and the cavity resonance wavelength. Finally, the angular and aperture resolved intensity noise exhibit a super-shot noise behavior in contrast to that of the total emission. We explain this difference with anticorrelations between various radial components which increase with the temperature-tuned extension of the spatial emission.

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    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.

  19. Cylindrical vector resonant modes achieved in planar photonic crystal cavities with enlarged air-holes

    NASA Astrophysics Data System (ADS)

    Chang, Kang; Fang, Liang; Zhao, Chenyang; Zhao, Jianlin; Gan, Xuetao

    2017-09-01

    We reveal a triangular-lattice planar photonic crystal supports Bloch modes with radially and azimuthally symmetric electric field distributions at the top band-edge of the first photonic band. Bifurcated from the corresponding Bloch modes, two cylindrical vector resonant modes are achieved by simply enlarging the central air-hole of the planar photonic crystal, which have high quality factors around 3,000 and small mode volume. The far-field radiations of the two resonant modes present high-quality cylindrical vector beam profiles. The resonant modes could be optimized by modifying the six nearest neighboring air-holes around the central defect. The cylindrically symmetric characteristics of the resonant mode's near- and far-fields might provide a new view to investigate light-matter interactions and device developments in planar photonic crystal cavities.

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

    SciTech Connect

    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.

  1. Simulation of Optical Resonators for Vertical-Cavity Surface-Emitting Lasers (vcsel)

    NASA Astrophysics Data System (ADS)

    Mansour, Mohy S.; Hassen, Mahmoud F. M.; El-Nozahey, Adel M.; Hafez, Alaa S.; Metry, Samer F.

    2010-04-01

    Simulation and modeling of the reflectivity and transmissivity of the multilayer DBR of VCSEL, as well as inside the active region quantum well are analyzed using the characteristic matrix method. The electric field intensity distributions inside such vertical-cavity structure are calculated. A software program under MATLAB environment is constructed for the simulation. This study was performed for two specific Bragg wavelengths 980 nm and 370 nm for achieving a resonant periodic gain (RPG)

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

    DOEpatents

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

    2003-08-19

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

  3. Interband cascade resonant cavity surface emitting LEDs for 2D-array scene projectors

    NASA Astrophysics Data System (ADS)

    Bradshaw, John L.; Bruno, John D.; Lascola, Kevin M.; Meissner, Gregory P.; Pham, John T.; Towner, Frederick J.

    2010-04-01

    The interband cascade (IC) technology is uniquely suited for fabrication of high-density 2-dimensional arrays of MWIR and LWIR emitters. In this talk, we briefly overview the fabrication and performance of MWIR Interband Cascade LED arrays and discuss the design, fabrication, and performance characteristics of vertically-emitting resonant cavity structures. We will assess the current performance of these structures for meeting the requirements of IR scene projection systems.

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

    PubMed

    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.

  5. Integrated system modeling analysis of a cryogenic multi-cell deflecting-mode cavity resonator

    NASA Astrophysics Data System (ADS)

    Shin, Young-Min; Church, Michael

    2013-09-01

    A deflecting mode cavity is the integral element for six-dimensional phase-space beam control in bunch compressors and emittance transformers at high energy beam test facilities. RF performance of a high-Q device is, however, highly sensitive to operational conditions, in particular in a cryo-cooling environment. Using analytic calculations and RF simulations, we examined cavity parameters and deflecting characteristics of TM110,π mode of a 5 cell resonator in a liquid nitrogen cryostat, which has long been used at the Fermilab A0 Photoinjector (A0PI). The sensitivity analysis indicated that the cavity could lose 30%-40% of deflecting force due to defective input power coupling accompanying non-uniform field distribution across the cells with 40 ˜ 50 MeV electron beam and 70-80 kW klystron power. Vacuum-cryomodules of the 5 cell cavity are planned to be installed at the Fermilab Advanced Superconducting Test Accelerator facility. Comprehensive modeling analysis integrated with multi-physics simulation tools showed that RF loading of 1 ms can cause a ˜5 K maximum temperature increase, corresponding to a ˜4.3 μm/ms deformation and a 1.32 MHz/K maximum frequency shift. The integrated system modeling analysis will improve design process of a high-Q cavity with more accurate prediction of cryogenic RF performance under a high power pulse operation.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

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

    DOE PAGES

    Huang, Yulu; Wang, Haipeng; Wang, Shaoheng; ...

    2016-12-09

    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,more » 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. Lastly, we demonstrate mode superposition in this cavity experimentally, which illustrates the kicking pulse generation concept.« less

  9. Magnetic resonance imaging analysis of water flow in the mantle cavity of live Mytilus galloprovincialis.

    PubMed

    Seo, Eriko; Ohishi, Kazue; Maruyama, Tadashi; Imaizumi-Ohashi, Yoshie; Murakami, Masataka; Seo, Yoshiteru

    2014-07-01

    Water flow inside the shell of Mytilus galloprovincialis was measured by phase-contrast magnetic resonance imaging (MRI). In seawater without algal cells at 23 °C, water approached the mussel from the posterior-ventral side, and entered through the inhalant aperture at a velocity of 40-20 mm s(-1). The flow rate in the lower mantle cavity decreased to 10-20 mm s(-1), the water flowed in the anterior-dorsal direction and approached the demibranches at a velocity of 5-10 mm s(-1). After passing through the lamellae to the upper mantle cavity, the water stretched the interlamellar cavity, turned to the posterior-dorsal direction and accumulated in the epibranchial cavity. The water flows came together at the ventral side of the posterior adductor muscle. The velocity increased more to than 50 mm s(-1) in the exhalant siphon, and exhaled out in the posterior-dorsal direction. The anterior-posterior direction of the flow was imaged every 1.92 s by the inflow effect of T1-weighted MRI. The flow seemed to be constant, and no cyclic motion of the mantles or the gills was detected. Spontaneous closure of the shells caused a quick drop of the flow in the mantle cavity. In the opening process of the shells, water flow in the interlamellar cavities increased before the opening, followed by an increase of flows in the exhalant siphon and inhalant aperture with minimum delay, reaching a plateau within 1 min of the shells opening. This provides direct evidence that the lateral cilia drive water in the mussel M. galloprovincialis. © 2014. Published by The Company of Biologists Ltd.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. High precision, rapid laser hole drilling

    DOEpatents

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2013-04-02

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  12. High-Precision Photometry with the RCT

    NASA Astrophysics Data System (ADS)

    Everett, M.; Howell, S.; Davis, D.; McGruder, C. H., III; Gelderman, R.; Guinan, E.; Mattox, J. R.; Walter, D. K.

    2003-05-01

    We plan to conduct a high-precision photometric search for transitting extra-solar planets using the refurbished 1.3 m (50 inch) Robotically-Controlled Telescope (RCT) at Kitt Peak. The photometric capabilities and extra-solar planet search strategy for the RCT are discussed. Refurbishment of the RCT has been made possible by NASA grant NAG58762.

  13. High Precision Pressure Measurement with a Funnel

    ERIC Educational Resources Information Center

    Lopez-Arias, T.; Gratton, L. M.; Oss, S.

    2008-01-01

    A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is…

  14. High precision measurements in crustal dynamic studies

    NASA Technical Reports Server (NTRS)

    Wyatt, F.; Berger, J.

    1984-01-01

    The development of high-precision instrumentation for monitoring benchmark stability and evaluating coseismic strain and tilt signals is reviewed. Laser strainmeter and tilt observations are presented. Examples of coseismic deformation in several geographic locations are given. Evidence suggests that the Earth undergoes elastic response to abrupt faulting.

  15. High Precision Pressure Measurement with a Funnel

    ERIC Educational Resources Information Center

    Lopez-Arias, T.; Gratton, L. M.; Oss, S.

    2008-01-01

    A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is…

  16. High precision, rapid laser hole drilling

    DOEpatents

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2005-03-08

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  17. High precision, rapid laser hole drilling

    DOEpatents

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2007-03-20

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  18. Development and Applications of Magnetooptical Measurement System Equipped with a Rotational Resonant Cavity in the Millimeter-Wave Region

    NASA Astrophysics Data System (ADS)

    Kimata, Motoi; Koyama, Keiichi; Ohta, Hitoshi; Oshima, Yugo; Motokawa, Mitsuhiro; Nishikawa, Hiroyuki; Kikuchi, Kouichi; Ikemoto, Isao

    2005-07-01

    A rotational resonant cavity equipped with a millimeter vector network analyzer (MVNA) and a 14 T solenoid type superconducting magnet has been developed. The available frequency range is about 50-100 GHz. The temperature can decrease to 1.5 K. The cavity can rotate within the precision of one degree. As an example of the application of the new resonant cavity, we have performed detailed magnetooptical measurements of an organic conductor to estimate the Fermi surface topology. The Fermi surface of the quasi-one-dimensional conductor (DMET)2I3 is discussed.

  19. Laser interferometric high-precision angle monitor for JASMINE

    NASA Astrophysics Data System (ADS)

    Niwa, Yoshito; Arai, Koji; Sakagami, Masaaki; Gouda, Naoteru; Kobayashi, Yukiyasu; Yamada, Yoshiyuki; Yano, Taihei

    2006-06-01

    The JASMINE instrument uses a beam combiner to observe two different fields of view separated by 99.5 degrees simultaneously. This angle is so-called basic angle. The basic angle of JASMINE should be stabilized and fluctuations of the basic angle should be monitored with the accuracy of 10 microarcsec in root-mean-square over the satellite revolution period of 5 hours. For this purpose, a high-precision interferometric laser metrogy system is employed. One of the available techniques for measuring the fluctuations of the basic angle is a method known as the wave front sensing using a Fabry-Perot type laser interferometer. This technique is to detect fluctuations of the basic angle as displacement of optical axis in the Fabry-Perot cavity. One of the advantages of the technique is that the sensor is made to be sensitive only to the relative fluctuations of the basic angle which the JASMINE wants to know and to be insensitive to the common one; in order to make the optical axis displacement caused by relative motion enhanced the Fabry-Perot cavity is formed by two mirrors which have long radius of curvature. To verify the principle of this idea, the experiment was performed using a 0.1m-length Fabry-Perot cavity with the mirror curvature of 20m. The mirrors of the cavity were artificially actuated in either relative way or common way and the resultant outputs from the sensor were compared.

  20. Numerical evaluation of aperture coupling in resonant cavities and frequency perturbation analysis

    NASA Astrophysics Data System (ADS)

    Dash, R.; Nayak, B.; Sharma, A.; Mittal, K. C.

    2014-01-01

    This paper presents a general formulation for numerical evaluation of the coupling between two identical resonant cavities by a small elliptical aperture in a plane common wall of arbitrary thickness. It is organized into two parts. In the first one we discuss the aperture coupling that is expressed in terms of electric and magnetic dipole moments and polarizabilities using Carlson symmetric elliptical integrals. Carlson integrals have been numerically evaluated and under zero thickness approximation, the results match with the complete elliptical integrals of first and second kind. It is found that with zero wall thickness, the results obtained are the same as those of Bethe and Collin for an elliptical and circular aperture of zero thickness. In the second part, Slater's perturbation method is applied to find the frequency changes due to apertures of finite thickness on the cavity wall.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Thermal Wave Resonator Cavity Applied to the Study of the Thermal Diffusivity of Coffee Infusions

    NASA Astrophysics Data System (ADS)

    Tepepa, B. Briseño; Marín, E.; Martín-Martínez, E. San; Orea, A. Cruz

    2009-10-01

    Among the photothermal methods, the photopyroelectric technique, in its several experimental configurations, has been extensively used to measure the thermal properties of liquids, mainly the thermal effusivity and diffusivity. In this paper, the use of the so-called thermal wave resonator cavity method, in the cavity-length-scan mode, to measure the thermal diffusivity of commercial coffee infusions with samples at different concentrations and degrees of degradation induced by heating cycles is reported. A linear relationship between the logarithm of the pyroelectric signal amplitude and the sample thickness was observed, in agreement with the basic theory for the experimental configuration used here, from which the thermal diffusivity values of the samples were obtained. The thermal diffusivity was found to be almost independent of the coffee concentration in water but that this parameter is sensitive to sample modifications induced by degradation. This work represents another step to demonstrate the capability of the used method for characterization of the thermal properties of liquids.

  3. Bloch FDTD simulation of slow optical wave resonance cavity in optical storage technology

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Lin, Zhaohua; Cai, Lihua

    2013-08-01

    Long chain series resonance cavity is suitable for transferring slow optical wave, which can be served as the basic device for optical storage technology. Micro-ring resonator is one kind of such a long chain structure, which is considered to be the basic component of optical integrated circuit and optical computer in the future. The discrete energy level has the potential to distinguish digital optical data. The optical delay characteristics make such a device possible to store the information for some time. The advantage of this device is that it has the potential to construct an optical storage device in small geometrical dimension and could use mature semiconductor manufacture capability to lower the design and manufacturing expenses. Many experimental results have proved a lot of material and geometrical coefficients are very important for such an optical delay device. New theory method is needed to calculate the periodical energy transfer and time delay characteristics, which can be compared with experimental result. The Bloch FDTD is presented for analysis of such a new optical device, based on the optical Bloch energy band theory. The energy band characteristics of micro-ring periodical optical waveguide device is discussed used that analytical method. This precise calculated method could be served as a useful tool for design the structure of such resonance cavity to achieve desired slow optical wave transfer performance.

  4. Misalignment sensitivity in an intra-cavity coherently combined crossed-Porro resonator configuration

    NASA Astrophysics Data System (ADS)

    Alperovich, Z.; Buchinsky, O.; Greenstein, S.; Ishaaya, A. A.

    2017-08-01

    We investigate the misalignment sensitivity in a crossed-Porro resonator configuration when coherently combining two pulsed multimode Nd:YAG laser channels. To the best of our knowledge, this is the first reported study of this configuration. The configuration is based on a passive intra-cavity interferometric combiner that promotes self-phase locking and coherent combining. Detailed misalignment sensitivity measurements are presented, examining both translation and angular deviations of the end prisms and combiner, and are compared to the results for standard flat end-mirror configurations. The results show that the most sensitive parameter in the crossed-Porro resonator configuration is the angular tuning of the intra-cavity interferometric combiner, which is ~±54 µrad. In comparison, with the flat end mirror configuration, the most sensitive parameter in the resonator is the angular tuning of the output coupler, which is ~±11 µrad. Thus, with the crossed-Porro configuration, we obtain significantly reduced sensitivity. This ability to reduce the misalignment sensitivity in coherently combined solid-state configurations may be beneficial in paving their way into practical use in a variety of demanding applications.

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

    PubMed

    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.

  6. Design and performance of resonant-cavity parallel baffles for duct silencing

    NASA Technical Reports Server (NTRS)

    Soderman, P. T.

    1981-01-01

    Resonant-cavity parallel baffles, either empty or with a thin absorbent lining, have been investigated as an alternative to fiberglass-filled baffles commonly used to control noise emission from large ducts. A method for predicting silencer attenuation is described, and it is shown that the new type of baffle is characterized by an acoustic performance similar to that of fibrous baffles, while being virtually immune to such problems as clogging, erosion, or settling. The emphasis of the study is on insertion loss measurements in a 7 by 10 ft wind tunnel.

  7. 30 GHz ultracompact electroabsorption modulator integrated with 980 nm VCSEL with resonance effect in coupled cavities

    NASA Astrophysics Data System (ADS)

    Dalir, Hamed; Koyama, Fumio

    2014-11-01

    We demonstrate an ultracompact (15-µm-long) electroabsorption slow-light modulator laterally integrated with a 980 nm VCSEL. The total device length is as small as 25 µm. A 3 dB small signal modulation bandwidth of over 30 GHz is obtained owing to the resonance effect in the coupled cavities. This bandwidth is far beyond the relaxation oscillation frequency of directly modulated VCSELs. Static extinction ratios of 4 and 8 dB are obtained at reverse bias voltages of 0.5 and 1.3 V for a 15-µm-long modulator, respectively.

  8. Piezoelectric Wind-Energy-Harvesting Device with Reed and Resonant Cavity

    NASA Astrophysics Data System (ADS)

    Ji, Jun; Kong, Fanrang; He, Liangguo; Guan, Qingchun; Feng, Zhihua

    2010-05-01

    A wind-energy-harvesting device utilizing the principle of a harmonica was created. A reed in a resonant cavity vibrated efficiently with the blowing wind, and a piezoelectric element stuck on the reed generated electricity. The dimensions of the wind inlet were approximately 30×20 mm2. The device was investigated with a wind speed ranging from 2.8 to 10 m/s. An output power of 0.5-4.5 mW was obtained with a matching load of 0.46 MΩ. The energy conversion efficiency of the device could reach up to 2.4%.

  9. Near-integrability and chaos in a resonant-cavity laser model

    NASA Astrophysics Data System (ADS)

    Holm, Darryl D.; Kovačič, Gregor; Wettergren, Thomas A.

    1995-02-01

    The dynamics of an ensemble of two-level atoms in a single-mode resonant laser cavity with external pumping and a weak coherent probe are investigated. Homoclinic orbits connected to the completely inverted atomic state are found analytically using linear perturbation theory (the Melnikov method) in the near-integrable limit, and are continued in the parameter space to O(1) parameter values using the bifurcation code AUTO. The breakup of these homoclinic orbits is believed to be a source of chaos in the system.

  10. Spectral engineering by flexible tunings of optical Tamm states and Fabry-Perot cavity resonance.

    PubMed

    Zhang, Xu-Lin; Song, Jun-Feng; Feng, Jing; Sun, Hong-Bo

    2013-11-01

    We present a design for spectral engineering in a metal dual distributed Bragg reflector (DBR)-based structure. Optical Tamm states and Fabry-Perot cavity mode, dual windows for light-matter interaction enhancement, can be excited simultaneously and tuned flexibly, including their respective bandwidth and resonant wavelength, due to the variable reflection phase from the outer DBR's internal surface. The design can find applications in solar cells for light trappings. Via calculations of overall absorptivity, the proposed simpler dual-states-based scheme is demonstrated to be almost as effective as the coherent-light-trapping scheme, owing to the dual-states-induced broader-band absorption enhancement.

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

    PubMed

    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 <10(-10) is -25.6 dBm, and the power penalty added after 25-km transmission is less than 2 dB for all 16 channels.

  12. Portable high precision pressure transducer system

    NASA Astrophysics Data System (ADS)

    Piper, T. C.; Morgan, J. P.; Marchant, N. J.; Bolton, S. M.

    A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank is presented. Since the response of the pressure transducer is temperature sensitive, it is continually housed in a battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on-board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum fluorescent display.

  13. High-Precision Computation and Mathematical Physics

    SciTech Connect

    Bailey, David H.; Borwein, Jonathan M.

    2008-11-03

    At the present time, IEEE 64-bit floating-point arithmetic is sufficiently accurate for most scientific applications. However, for a rapidly growing body of important scientific computing applications, a higher level of numeric precision is required. Such calculations are facilitated by high-precision software packages that include high-level language translation modules to minimize the conversion effort. This paper presents a survey of recent applications of these techniques and provides some analysis of their numerical requirements. These applications include supernova simulations, climate modeling, planetary orbit calculations, Coulomb n-body atomic systems, scattering amplitudes of quarks, gluons and bosons, nonlinear oscillator theory, Ising theory, quantum field theory and experimental mathematics. We conclude that high-precision arithmetic facilities are now an indispensable component of a modern large-scale scientific computing environment.

  14. Portable high precision pressure transducer system

    DOEpatents

    Piper, Thomas C.; Morgan, John P.; Marchant, Norman J.; Bolton, Steven M.

    1994-01-01

    A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum florescent display.

  15. Portable high precision pressure transducer system

    DOEpatents

    Piper, T.C.; Morgan, J.P.; Marchant, N.J.; Bolton, S.M.

    1994-04-26

    A high precision pressure transducer system is described for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum fluorescent display. 2 figures.

  16. High precision neutron inelastic cross section measurements

    NASA Astrophysics Data System (ADS)

    Olacel, A.; Belloni, F.; Borcea, C.; Boromiza, M.; Dessagne, Ph.; Henning, G.; Kerveno, M.; Negret, A.; Nyman, M.; Pirovano, E.; Plompen, A.

    2017-06-01

    High precision neutron inelastic scattering cross section data are very important for the development of the new generation of nuclear reactors (Gen IV). Our experiments, performed using the GELINA neutron source and the GAINS spectrometer of the European Commission Joint Research Center, Geel, produce highly reliable and precise cross section data. We will present the details of the setup and the data analysis technique allowing production of such unique results, and we will show examples of two experimental results.

  17. High-precision arithmetic in mathematical physics

    DOE PAGES

    Bailey, David H.; Borwein, Jonathan M.

    2015-05-12

    For many scientific calculations, particularly those involving empirical data, IEEE 32-bit floating-point arithmetic produces results of sufficient accuracy, while for other applications IEEE 64-bit floating-point is more appropriate. But for some very demanding applications, even higher levels of precision are often required. Furthermore, this article discusses the challenge of high-precision computation, in the context of mathematical physics, and highlights what facilities are required to support future computation, in light of emerging developments in computer architecture.

  18. High-sensitivity double-cavity silicon photonic-crystal resonator for label-free biosensing

    NASA Astrophysics Data System (ADS)

    Sana, Amrita Kumar; Amemiya, Yoshiteru; Yokoyama, Shin

    2017-04-01

    We demonstrated a two-dimensional double-cavity silicon photonic-crystal resonator based neighboring hole radius modulation. By theoretical and experimental analyses, we confirmed that the quality factor (Q-factor) increases at a certain neighboring hole radius. Experimentally, we showed Q-factors of (1.93-2.02) × 105. Moreover, by using sucrose solution, we measured a sensitivity of 1571 nm/RIU (refractive index unit), which is the highest sensitivity ever reported for such a two-dimensional photonic-crystal-based resonator type device. We reported the detection limit (DL) of the refractive index change of (4.15-4.34) × 10-6 RIU, which is one of the best in previous reports.

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

    PubMed

    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.

  20. Lasing properties of non-resonant single quantum dot-cavity system under incoherent excitation.

    PubMed

    Guan, Huan; Yao, Peijun; Yu, Wenhai; Wang, Pei; Ming, Hai

    2012-12-17

    Single quantum dot laser has earned extensive interest due to its peculiar properties, however, most of works are focused on the resonant case. In this paper, the lasing oscillation based on off-resonant quantum dot (QD)-cavity system is investigated detailedly through two-electrons QD model. By gradually increasing the pump rate, the typical lasing signatures are shown with and without detuning, include the spectral transition from multiple peaks to single peak, and antibunching to Poissonian distribution. It is also demonstrated how detuning factor strongly influence photon statistics and emission properties, specially, the side peak of spectra induced by the exchange energy (named "sub-peak") will go across the main peak from left to right when the detuning is gradually increased, and, furthermore, we find the "sub-peak cross of spectra" will facilitate the lasing oscillation because of the existence of exchange energy.

  1. Comparing resonant photon tunneling via cavity modes and Tamm plasmon polariton modes in metal-coated Bragg mirrors.

    PubMed

    Leosson, K; Shayestehaminzadeh, S; Tryggvason, T K; Kossoy, A; Agnarsson, B; Magnus, F; Olafsson, S; Gudmundsson, J T; Magnusson, E B; Shelykh, I A

    2012-10-01

    Resonant photon tunneling was investigated experimentally in multilayer structures containing a high-contrast (TiO(2)/SiO(2)) Bragg mirror capped with a semitransparent gold film. Transmission via a fundamental cavity resonance was compared with transmission via the Tamm plasmon polariton resonance that appears at the interface between a metal film and a one-dimensional photonic bandgap structure. The Tamm-plasmon-mediated transmission exhibits a smaller dependence on the angle and polarization of the incident light for similar values of peak transmission, resonance wavelength, and finesse. Implications for transparent electrical contacts based on resonant tunneling structures are discussed.

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

    NASA Astrophysics Data System (ADS)

    Yildiz, Mehmet Serhan; Celik, Murat

    2017-04-01

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

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

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Chen, J. E.; Kang, M. L.; Lu, Y. R.; Xia, W. L.; Gao, S. L.; Guo, Z. Y.; Liu, G.; Peng, S. X.; Ren, H. T.; Yan, X. Q.; Zhao, J.; Zhu, K.

    2012-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Jiang, Jiulong; Yao, Hong; Du, Jun; Zhao, Jinbo

    2016-11-01

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

  5. Note: Vector network analyzer-ferromagnetic resonance spectrometer using high Q-factor cavity.

    PubMed

    Lo, C K; Lai, W C; Cheng, J C

    2011-08-01

    A ferromagnetic resonance (FMR) spectrometer whose main components consist of an X-band resonator and a vector network analyzer (VNA) was developed. This spectrometer takes advantage of a high Q-factor (9600) cavity and state-of-the-art VNA. Accordingly, field modulation lock-in technique for signal to noise ratio (SNR) enhancement is no longer necessary, and FMR absorption can therefore be extracted directly. Its derivative for the ascertainment of full width at half maximum height of FMR peak can be found by taking the differentiation of original data. This system was characterized with different thicknesses of permalloy (Py) films and its multilayer, and found that the SNR of 5 nm Py on glass was better than 50, and did not have significant reduction even at low microwave excitation power (-20 dBm), and at low Q-factor (3000). The FMR other than X-band can also be examined in the same manner by using a suitable band cavity within the frequency range of VNA.

  6. Note: Vector network analyzer-ferromagnetic resonance spectrometer using high Q-factor cavity

    NASA Astrophysics Data System (ADS)

    Lo, C. K.; Lai, W. C.; Cheng, J. C.

    2011-08-01

    A ferromagnetic resonance (FMR) spectrometer whose main components consist of an X-band resonator and a vector network analyzer (VNA) was developed. This spectrometer takes advantage of a high Q-factor (9600) cavity and state-of-the-art VNA. Accordingly, field modulation lock-in technique for signal to noise ratio (SNR) enhancement is no longer necessary, and FMR absorption can therefore be extracted directly. Its derivative for the ascertainment of full width at half maximum height of FMR peak can be found by taking the differentiation of original data. This system was characterized with different thicknesses of permalloy (Py) films and its multilayer, and found that the SNR of 5 nm Py on glass was better than 50, and did not have significant reduction even at low microwave excitation power (-20 dBm), and at low Q-factor (3000). The FMR other than X-band can also be examined in the same manner by using a suitable band cavity within the frequency range of VNA.

  7. NIR resonant-cavity-enhanced InP/InGaAs strained quantum well interband photodetector

    NASA Astrophysics Data System (ADS)

    Jourba, Serguei; Besland, Marie-Paule; Gendry, Michel; Garrigues, Michel; Leclercq, Jean L.; Rojo-Romeo, Pedro; Viktorovitch, Pierre; Cortial, Sebastein; Hugon, Xavier; Pautet, Christophe

    1999-04-01

    We demonstrate NIR (1.8 micrometer - 2.3 micrometer) resonant photo-detectors based on inter-band (Ecl- Ehhl) absorption in strain compensated, indium rich, InGaAs quantum wells (QW). Extremely low room temperature dark current densities are achieved by reduction of the active layer thickness combined with low defect density of the pseudomorphic strain compensated QWs. The weak absorption of the QW is enhanced by embedding the quantum well into a vertical resonant cavity. We present the experimental results for a demonstrator designed for a wavelength of 2 micrometer. The device, based on a single In(subscript 0.83)Ga(subscript 0.17)As quantum well and tensile strained barriers for strain compensation, exhibits a selectivity of 9 nm and 18% quantum efficiency. InP/InGaAs and Si/SiO(subscript 2) material systems are used for the bottom and top distributed Bragg reflectors (DBR) of the cavity, with 20 pairs and 2 pairs respectively. The semiconductor structure is grown by MOCVD. The top Si/SiO(subscript 2) DBR is deposited after fabrication of p-i-n planar photodiodes. Typical dark current densities are lower than 10(superscript -7) A/cm(superscript 2) at -2 V bias. Conditions for extension of the operating wavelength up to 2.3 micrometer have been obtained experimentally using InAs/GaAs superlattice deposition to increase the thickness of the strained QW. A prospective tunable detector based on an actuable micro-machined air cavity and air/InP bottom DBR is proposed.

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

    PubMed

    Yang, Xulei; Song, Qing; Su, Yi

    2017-02-03

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

  9. Resonant cavity perturbation: a promising new method for the assessment of total body water in children.

    PubMed

    Oldroyd, Brian; Robinson, Martin; Lindley, Elizabeth; Rhodes, Laura; Hind, Karen

    2015-12-01

    The accurate measurement of total body water (TBW) in children has important clinical and nutritional applications. Resonant cavity perturbation (RCP) is a new method for estimating TBW. This method measures the dielectric properties of the body which are related to body water. For RCP measurements, each subject lay supine on a bed inside a screened room which acts as a resonant cavity. A network analyser measures the frequencies of two low-order cavity resonances of the room, with electric-field vectors that were respectively vertical and horizontal, the resonant frequency shifts relative to the empty room are then derived. These frequency shifts correlates with TBW. The aims of this present study were to (a) develop TBW(RCP) predictive equations for children using TBWdil as the criterion method, (b) cross-validate the derived equations, (c) determine precision of the TBW(RCP) method, and (d) compare the criterion method TBWdil with three methods of estimating TBW: RCP, MFBIS and anthropometry.Predictive equations, independent of sex, were developed with linear regression in a group of 36 children. The relationship between combined RCP frequency shifts and TBWdilution had an r2  =  0.90 and standard error of the estimate (SEE)  =1.42 kg. Multiple regression analysis, that included a term for body mass index, only had a small effect on r2  =  0.93 and SEE  =  1.25 kg. In vivo TBW precision for the vertical, horizontal and combined frequency modes ranged from 0.7 to 3.4%. Bland-Altman analysis indicated close agreement between the criterion method TBWdil and the three other methods of TBW estimation. Mean differences were TBW(RCP(2))  =  0.01  ±  /-  1.34 kg, TBW(MFBIS)  =  0.45  ±  /-  1.35 kg, TBWAnthropometry  =  0.29  ±  /-  1.29 kg.Currently the RCP method does not significantly improve the prediction of TBW compared to MFBIS and anthropometry in this initial

  10. Electric Quadrupole Transition Measurements of Hydrogen Molecule with High Precision

    NASA Astrophysics Data System (ADS)

    Cheng, Cun-Feng; Wang, Jin; Tan, Yan; Liu, An-Wen; Hu, Shui-Ming

    2013-06-01

    Molecular hydrogen is the most fundamental, and the only neutral molecule expected to be both calculated and measured with extremely high accuracy. High-precision measurements of its spectroscopy, especially the levels at the electric ground state, play an important role in the examination of precise quantum chemistry calculations and some fundamental physical constants. In the infrared region, H_2, being a homonuclear diatomic molecule, only has very weak electric quadrupole transitions. We established a new spectroscopy approach with ultra-high precision and sensitivity as well, based on a laser-locked cavity ring-down spectrometer. An equivalent absorption path-length of thousands of kilometers and a frequency precision of 10^{-5} cm^{-1} have been achieved. Ro-vibrational spectra of the second overtone of H_2 have been recorded. The obtained results will provide a direct examination of the high-accuracy quantum theory. It also shades light on the determination of fundamental physical constants such as the electron/proton mass ratio in a molecular system.

  11. High precision detector robot arm system

    DOEpatents

    Shu, Deming; Chu, Yong

    2017-01-31

    A method and high precision robot arm system are provided, for example, for X-ray nanodiffraction with an X-ray nanoprobe. The robot arm system includes duo-vertical-stages and a kinematic linkage system. A two-dimensional (2D) vertical plane ultra-precision robot arm supporting an X-ray detector provides positioning and manipulating of the X-ray detector. A vertical support for the 2D vertical plane robot arm includes spaced apart rails respectively engaging a first bearing structure and a second bearing structure carried by the 2D vertical plane robot arm.

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

    SciTech Connect

    Abudureyimu, Reheman; Huang, Chunning; Liu, Yun

    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.

  13. Full 3-D TLM simulations of the Earth-ionosphere cavity: Effect of conductivity on the Schumann resonances

    NASA Astrophysics Data System (ADS)

    Toledo-Redondo, S.; Salinas, A.; Fornieles, J.; Portí, J.; Lichtenegger, H. I. M.

    2016-06-01

    Schumann resonances can be found in planetary atmospheres, inside the cavity formed by the conducting surface of the planet and the lower ionosphere. They are a powerful tool to investigate both the electric processes that occur in the atmosphere and the characteristics of the surface and the lower ionosphere. Results from a full 3-D model of the Earth-ionosphere electromagnetic cavity based on the Transmission-Line Modeling (TLM) method are presented. A Cartesian scheme with homogeneous cell size of 10 km is used to minimize numerical dispersion present in spherical schemes. Time and frequency domain results have been obtained to study the resonance phenomenon. The effect of conductivity on the Schumann resonances in the cavity is investigated by means of numerical simulations, studying the transition from resonant to nonresonant response and setting the conductivity limit for the resonances to develop inside the cavity. It is found that the transition from resonant to nonresonant behavior occurs for conductivity values above roughly 10-9 S/m. For large losses in the cavity, the resonances are damped, but, in addition, the peak frequencies change according to the local distance to the source and with the particular electromagnetic field component. These spatial variations present steep variations around each mode's nodal position, covering distances around 1/4 of the mode wavelength, the higher modes being more sensitive to this effect than the lower ones. The dependence of the measured frequency on the distance to the source and particular component of the electric field offers information on the source generating these resonances.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Spectrum of the cavity-QED microlaser: strong coupling effects in the frequency pulling at off resonance.

    PubMed

    Hong, H-G; Seo, W; Song, Y; Lee, M; Jeong, H; Shin, Y; Choi, W; Dasari, R R; An, K

    2012-12-14

    We report the first experimental observation of the cavity-QED microlaser spectrum, specifically the unconventional frequency pulling brought by a strong atom-cavity coupling at off resonance. The pulling is enhanced quadratically by the atom-cavity coupling to result in a sensitive response to the number of pumping atoms (2.1 kHz per atom maximally). Periodic variation of the pulling due to the coherent Rabi oscillation is also observed as the number of pumping atoms is increased across multiple thresholds.

  16. Research about the high precision temperature measurement

    NASA Astrophysics Data System (ADS)

    Lin, J.; Yu, J.; Zhu, X.; Zeng, Z.; Deng, Y.

    2012-12-01

    High precision temperature control system is one of most important support conditions for tunable birefringent filter.As the first step,we researched some high precision temperature measurement methods for it. Firstly, circuits with a 24 bit ADC as the sensor's reader were carefully designed; Secondly, an ARM porcessor is used as the centrol processing unit, it provides sufficient reading and procesing ability; Thirdly, three kinds of sensors, PT100, Dale 01T1002-5 thermistor, Wheatstone bridge(constructed by pure copper and manganin) as the senor of the temperature were tested respectively. The resolution of the measurement with these three kinds of sensors are all better than 0.001 that's enough for 0.01 stability temperature control. Comparatively, Dale 01T1002-5 thermistor could get the most accurate temperature of the key point, Wheatstone bridge could get the most accurate mean temperature of the whole layer, both of them will be used in our futrue temperature controll system.

  17. Analytical description of quasi-normal mode in resonant plasmonic nano cavities

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Liu, Haitao; Jia, Hongwei; Zhong, Ying

    2016-03-01

    We propose an analytical model of quasi-normal mode (QNM) for resonant plasmonic nano cavities formed by sub wavelength grooves in metallic substrate. The QNM has shown great advantages in understanding and calculating the frequency response of resonant nano-structures. With our model we show that the QNM originates from a resonance of the fundamental mode in every individual groove and its interaction via surface waves. Analytical expression for the complex eigenfrequency as well as the field distribution of the QNM can be derived from the model. With the analytical model and a few assumptions on the scattered field, the legitimacy of the expansion of scattered field with QNMs under external illuminations is justified with the Mittag-Leffler's theorem of meromorphic function. The expansion coefficients of QNMs are analytically expressed with a finite set of elementary scattering coefficients, which avoids the calculation of the mode volume of QNMs that have a spatial divergence at infinity. The model clarifies the physical origin of QNMs and drastically reduces the computational load of QNMs, especially for a large ensemble of grooves for which brute-force numerical tools are not available. The validity of the proposed model is tested against fully vectorial numerical results.

  18. Resonant cavity based time-domain multiplexing techniques for coherently combined fiber laser systems

    NASA Astrophysics Data System (ADS)

    Zhou, T.; Ruppe, J.; Stanfield, P.; Nees, J.; Wilcox, R.; Galvanauskas, A.

    2015-10-01

    This paper describes novel time-domain multiplexing techniques that use various resonant cavity configurations for increasing pulse energy extraction per each parallel amplification channel of a coherently combined array. Two different techniques are presented: a so-called N2 coherent array combining technique, applicable to a periodic pulse train, and a coherent pulse stacking amplification (CPSA) technique, applicable to a pulse burst. The first technique is a coherent combining technique, which achieves simultaneous beam combining and time-domain pulse multiplexing/down-counting using traveling-wave Fabry-Perot type resonators. The second technique is purely a time-domain pulse multiplexing technique, used with either a single amplifier or an amplifier array, which uses traveling-wave Gires-Tourmois type resonators. The importance of these techniques is that they can enable stacking of very large number of pulses, thus increasing effective amplified-pulse duration potentially by 102 to 103 times, and reducing fiber array size by the corresponding factor. This could lead to very compact coherently combined arrays even for generating very high pulse energies in the range of 1 to 100 J.

  19. Formation of long nanosecond rectangular pulses in the active RF pulse compression system with a compact resonant cavity

    NASA Astrophysics Data System (ADS)

    Artemenko, S. N.; Gorev, S. A.; Igumnov, V. S.; Yushkov, Yu G.

    2017-05-01

    This work presents the results of the study of an active microwave pulse compression system capable of forming the rectangular pulses with duration ∼10-100 ns, while its dimensions are several times smaller than the radiated wave train. Such compression system is based on the compact planar-voluminal resonant cavity constructed in the shape of a meander from waveguide sections and H-plane tees. The resonant cavity sections are parallel and are in the same plane with tees. The energy input element is located in the input end of the first section. The output device designed as an H-plane tee interference switch is connected to the output end of the last section. Each end of remaining sections is connected through a straight arm to an H-tee with a short-circuited quarter-wave second straight arm. The side arm of each tee is connected with the side arm of the tee in the next section, thus coupling the sections. The short-circuited arm provides the “open” mode and transmission of the wave from tee to tee. We determined the expressions for wave amplitudes in the components of the meander resonant cavity made of three sections and analyzed the expressions as the functions of the parameters determining the oscillation range and energy distribution in the resonant cavity. Experiments demonstrated that under certain conditions the compressors with such resonant cavity could generate nearly rectangular pulses with duration equal to the time of wave two-way traveling along the resonant cavity, and with the power compatible with that of the wave in the resonant cavity, and the length of the radiated wave train several-fold exceeding the size of the compressor. At pulse duration equal to 25 ns, the gain coefficient was 13 dB and pulse power was 40 MW. The work demonstrates the possibility to change the geometry of the resonant cavity by rearranging its components without changing the output pulse parameters.

  20. Gaseous Absorption and Dispersion of Sound in a Resonant Cylindrical Cavity: AN Acoustic and Photoacoustic Study

    NASA Astrophysics Data System (ADS)

    Beckwith, Clyfe Gordon

    This research investigated the feasibility of accurately measuring Virial coefficients in an acoustically resonant cylindrical cavity. Gases studied were: Argon, Helium, Nitrogen, Carbon Dioxide, and Methane. Parameters considered were: resonant frequencies (f_ {rm r}- also a measure of speed of sound), quality factors (Q), and signal amplitudes. We studied the longitudinal modes smaller than 2000 Hz, at room temperature and at pressures of 200, 500, and 800 mm of Hg. The choice of the longitudinal modes was predetermined by our wish to compare acoustic and photoacoustic resonance techniques of the same mode. The acoustic excitation is limited to the longitudinal modes and is achieved by placing a loudspeaker close to one end of the cavity. Photoacoustically we excite a small concentration of molecular Iodine, mixed in with the buffer gases, by a periodically interrupted Xenon light beam. By increasing the length of the cavity we could decrease the space between the modes of frequency. Our observations focused on the behaviors that (a) f_{rm r} shifted with pressure, (b) the f_{rm r} deviated from the simple laws of harmonics, and (c) the amplitudes for the two techniques varied differently with frequency. Effect (a) is due to the fact that the gases are not "ideal", and due to the presence of boundary layers caused by thermal conduction and viscosity gradients. Effect (b) arises because of the f_{rm r}'s mode dependence, caused by the wave scattering due to imperfect geometrical symmetries. Effect (c) is governed by the coupling factors. All measurements could theoretically be justified to within instrumental error, the only noted discrepancy is the lack of a theoretical mode dependence. We conclude that it is feasible to study the accuracy of Virial coefficients of simple gases provided that the boundary layer loss effects and the mode dependent wave scattering can be quantified; in regions of high pressures and high frequencies the Virial effects dominate the

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

    PubMed

    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.

  2. Plasmonic induced transparency in a coupled system composed of metal-insulate-metal stub and trapezoid cavity resonator

    NASA Astrophysics Data System (ADS)

    Zheng, Pengfei; Yang, Huimin; Jiao, Linsen; Fan, Meiyong; Yun, Binfeng; Cui, Yiping

    2017-08-01

    A plasmonic induced transparency system constructed by a metal-insulate-metal stub coupled with a trapezoid cavity resonator was proposed. The results show that the spectra of different narrow modes in the trapezoid resonator can overlap with the broad stub mode and induce the plasmonic induced transparency effect. However, some of them cannot produce a plasmonic induced transparency effect because there is hardly any near field overlap between the trapezoid cavity mode and the stub mode, which was proved by the mode field distributions in the coupled resonator system. The ;disappeared; plasmonic induced transparency can be reproduced by changing the relative position between the stub and trapezoid resonator. Also the coupling strength can be modulated by this method to manipulate the plasmonic induced transparency and slow light effect.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-08-01

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

  5. Nanosecond pulse signals restoration via stochastic resonance in the Fabry-Perot cavity with graphene

    NASA Astrophysics Data System (ADS)

    Chang, Zheng; Liu, Hongjun; Huang, Nan; Wang, Zhaolu; Han, Jing

    2017-07-01

    We investigate a technology for reconstructing nanosecond pulse noise hidden signals via stochastic resonance, which is based on optical bistability in the Fabry-Perot (F-P) cavity with graphene. The bistable properties are analyzed with different initial wavelengths and Fermi energies. The system is tunable and the bistable behavior of the output intensity can be accurately controlled to obtain a cross-correlation gain larger than 10 in a wide range of input signal-to-noise (SNR) ratio from 1:8 to 1:45. Meanwhile, the distortion of the output signal and the pulse tailing caused by the phase delay can be reduced to a negligible level. This work provides a potential method for detecting low-level or hidden pulse signals in various communication fields.

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

    PubMed Central

    Chistiakova, Maria V.; Shi, Ce; Armani, Andrea M.

    2015-01-01

    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. PMID:25785307

  7. Cavity resonance absorption in ultra-high bandwidth CRT deflection structure by a resistive load

    DOEpatents

    Dunham, M.E.; Hudson, C.L.

    1993-05-11

    An improved ultra-high bandwidth helical coil deflection structure for a cathode ray tube is described comprising a first metal member having a bore therein, the metal walls of which form a first ground plane; a second metal member coaxially mounted in the bore of the first metal member and forming a second ground plane; a helical deflection coil coaxially mounted within the bore between the two ground planes; and a resistive load disposed in one end of the bore and electrically connected to the first and second ground planes, the resistive load having an impedance substantially equal to the characteristic impedance of the coaxial line formed by the two coaxial ground planes to inhibit cavity resonance in the structure within the ultra-high bandwidth of operation. Preferably, the resistive load comprises a carbon film on a surface of an end plug in one end of the bore.

  8. Cavity resonance absorption in ultra-high bandwidth CRT deflection structure by a resistive load

    DOEpatents

    Dunham, Mark E.; Hudson, Charles L.

    1993-01-01

    An improved ultra-high bandwidth helical coil deflection structure for a hode ray tube is described comprising a first metal member having a bore therein, the metal walls of which form a first ground plane; a second metal member coaxially mounted in the bore of the first metal member and forming a second ground plane; a helical deflection coil coaxially mounted within the bore between the two ground planes; and a resistive load disposed in one end of the bore and electrically connected to the first and second ground planes, the resistive load having an impedance substantially equal to the characteristic impedance of the coaxial line formed by the two coaxial ground planes to inhibit cavity resonance in the structure within the ultra-high bandwidth of operation. Preferably, the resistive load comprises a carbon film on a surface of an end plug in one end of the bore.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  10. Spectral singularity in composite systems and simulation of a resonant lasing cavity

    NASA Astrophysics Data System (ADS)

    Zhang, X. Z.; Li, G. R.; Song, Z.

    2017-10-01

    We investigate herein the existence of spectral singularities (SSs) in composite systems that consist of two separate scattering centers A and B embedded in one-dimensional free space, with at least one scattering center being non-Hermitian. We show that such composite systems have an SS at kc if the reflection amplitudes rA≤ft(kc\\right) and rB≤ft(kc\\right) of the two scattering centers satisfy the condition rR A≤ft(kc\\right) rLB≤ft(kc\\right) ei2kc≤ft(xB-xA\\right) =1 . We also extend the condition to the system with multi-scattering centers. As an application, we construct a simple system to simulate a resonant lasing cavity.

  11. Continuum visible spectra from InBr discharge excited in a microwave resonant cavity

    NASA Astrophysics Data System (ADS)

    Chen, Yuming; Chen, Dahua

    2007-10-01

    Emissions from InBr radiation have been investigated in a microwave resonant cavity system. We demonstrate that with proper operation the emission spectra of InBr can be a continuum in the visible range and can be suitable for lighting applications. The continuum spectra are stronger with an increase in input microwave power. In our system, a high color rendering index of 97 can be obtained from the bulb with 25mg InBr and 800W input microwave power. The spectral lines 410.1 and 451.1nm from In >I play an important role to balance the spectral distribution for lighting requirements. The continuum spectra may be due to the transition of Rydberg states to the C state of InBr molecules.

  12. Detection of subsurface cavity structures using contact-resonance atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Ma, Chengfu; Chen, Yuhang; Arnold, Walter; Chu, Jiaru

    2017-04-01

    To meet the surging demands for quantitative and nondestructive testing at the nanoscale in various fields, ultrasonic-based scanning probe microscopy techniques, such as contact-resonance atomic force microscopy (CR-AFM), have attracted increased attention. Despite considerable success in subsurface nanostructure or defect imaging, the detecting capabilities of CR-AFM have not been fully explored yet. In this paper, we present an analytical model of CR-AFM for detecting subsurface cavities by adopting a circular freestanding membrane structure as an equivalent cavity. The parameters describing the detection limits of CR-AFM for such structures include the detecting depth and the detectable area. These parameters are systematically studied for different cantilever eigenmodes for structures of different sizes and depths. The results show that the detecting depth depends on the structure size. The higher eigenmodes generally provide better detecting capabilities than the lower ones. For an experimental verification, samples were prepared by covering a polymethylmethacrylate (PMMA) substrate with open pores at its surface with HOPG flakes. CR-AFM imaging on the HOPG-covered area was carried out using different eigenmodes in order to detect the pores in the PMMA. In addition, the influence of the applied tip load is also discussed.

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

    PubMed

    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.

  14. A numerically efficient damping model for acoustic resonances in microfluidic cavities

    SciTech Connect

    Hahn, P. Dual, J.

    2015-06-15

    Bulk acoustic wave devices are typically operated in a resonant state to achieve enhanced acoustic amplitudes and high acoustofluidic forces for the manipulation of microparticles. Among other loss mechanisms related to the structural parts of acoustofluidic devices, damping in the fluidic cavity is a crucial factor that limits the attainable acoustic amplitudes. In the analytical part of this study, we quantify all relevant loss mechanisms related to the fluid inside acoustofluidic micro-devices. Subsequently, a numerical analysis of the time-harmonic visco-acoustic and thermo-visco-acoustic equations is carried out to verify the analytical results for 2D and 3D examples. The damping results are fitted into the framework of classical linear acoustics to set up a numerically efficient device model. For this purpose, all damping effects are combined into an acoustofluidic loss factor. Since some components of the acoustofluidic loss factor depend on the acoustic mode shape in the fluid cavity, we propose a two-step simulation procedure. In the first step, the loss factors are deduced from the simulated mode shape. Subsequently, a second simulation is invoked, taking all losses into account. Owing to its computational efficiency, the presented numerical device model is of great relevance for the simulation of acoustofluidic particle manipulation by means of acoustic radiation forces or acoustic streaming. For the first time, accurate 3D simulations of realistic micro-devices for the quantitative prediction of pressure amplitudes and the related acoustofluidic forces become feasible.

  15. Effects of Energetic Solar Emissions on the Earth-Ionosphere Cavity of Schumann Resonances

    NASA Astrophysics Data System (ADS)

    Sátori, Gabriella; Williams, Earle; Price, Colin; Boldi, Robert; Koloskov, Alexander; Yampolski, Yuri; Guha, Anirban; Barta, Veronika

    2016-07-01

    Schumann resonances (SR) are the electromagnetic oscillations of the spherical cavity bounded by the electrically conductive Earth and the conductive but dissipative lower ionosphere (Schumann in Z Naturforsch A 7:6627-6628, 1952). Energetic emissions from the Sun can exert a varied influence on the various parameters of the Earth's SR: modal frequencies, amplitudes and dissipation parameters. The SR response at multiple receiving stations is considered for two extraordinary solar events from Solar Cycle 23: the Bastille Day event (July 14, 2000) and the Halloween event (October/November 2003). Distinct differences are noted in the ionospheric depths of penetration for X-radiation and solar protons with correspondingly distinct signs of the frequency response. The preferential impact of the protons in the magnetically unshielded polar regions leads to a marked anisotropic frequency response in the two magnetic field components. The general immunity of SR amplitudes to these extreme external perturbations serves to remind us that the amplitude parameter is largely controlled by lightning activity within the Earth-ionosphere cavity.

  16. High precision tracking method for solar telescopes

    NASA Astrophysics Data System (ADS)

    Guo, Jingjing; Yang, Yunfei; Feng, Song; Ji, Kanfan; Lin, Jiaben; Zeng, Zhen; Wang, Bingxiang

    2016-07-01

    A high-precision real-time tracking method for solar telescopes was introduced in this paper based on the barycenter of full-disk solar images algorithm. To make sure the calculation was accurate and reliable, a series of strictly logic limits were set, such as setting gray threshold, judging the displacement of the barycenter and measuring the deviation from a perfect disk. A closed-loop control system was designed in the method. We located the barycenter of the full-disk images which recorded by large array CCD image sensor in real time and eliminate noise caused by bad weather, such as clouds and fog. The displacement of the barycenter was analyzed and transferred into control signal drove the motor to adjust the axis of telescope. An Ethernet interface was also provided for remote control. In the observation, the precision of this new method was better than 1″/30 minutes.

  17. High precision phase-shifting electron holography

    PubMed

    Yamamoto; Kawajiri; Tanji; Hibino; Hirayama

    2000-01-01

    Today's information-oriented society requires high density and high quality magnetic recording media. The quantitative observation of fine magnetic structures by electron holography is greatly anticipated in the development of such new recording materials. However, the magnetic fields around particles <50 nm have not been observed, because the fields are too weak to observe in the usual way. Here we present a highly precise phase measurement technique: improved phase-shifting electron holography. Using this method, the electric field around a charged polystyrene latex particle (100 nm in diameter) and the magnetic field around iron particles (30 nm in diameter) are observed precisely. A precision of the reconstructed phase image of 2pi/300 rad is achieved in the image of the latex particle.

  18. Microwave Properties of Hyaluronate Solutions Using a Resonant Microwave Cavity as a Probe.

    NASA Astrophysics Data System (ADS)

    Jani, Shirish Keshavlal

    1980-12-01

    Physiological functions of a biomacromolecule seem to be closely related to its molecular conformations. The knowledge of any conformational changes due to changes in its environment may lead to a proper understanding of its functions. Hyaluronic acid, a biomacromolecule with unusually high molecular weight and some important biological functions is the subject of the present work. The conformational changes in human umbilical cord hyaluronic acid molecules in various environments were observed by monitoring their dielectric response at microwave frequencies. A tunable resonant microwave cavity operated in the TE(,011) mode was used as a probe in monitoring the dielectric response of the hyaluronate solutions. Both the real and imaginary parts of complex dielectric constant and the loss tangent for the solutions were obtained by utilizing equations for perturbation of a resonant cavity. Dielectric changes at room temperature were observed in aqueous solutions of hyaluronic acid as a function of concentration ranging from 0 to 350 mg/ml. The data indicate the existence of ordered phases in hyaluronate solutions at selective concentrations; that is, the hyaluronate molecule exhibits lyotropic type transitions. Hyaluronate solutions at 1.5 and 3 mg/ml concetrations were studied at various pH in the range 6-8 and at constant ionic strength 0.1. The pH-dependent dielectric changes were observed in hyaluronate solutions at both these concentrations. A temperature-dependent transition in hyaluronate solution of 120 mg/ml concentration was observed at physiological temperature. It is shown that this temperature-dependent behavior can be related to the orientational polarizability term in the Debye theory of polar molecules in liquids.

  19. High precision radial velocities with GIANO spectra

    NASA Astrophysics Data System (ADS)

    Carleo, I.; Sanna, N.; Gratton, R.; Benatti, S.; Bonavita, M.; Oliva, E.; Origlia, L.; Desidera, S.; Claudi, R.; Sissa, E.

    2016-06-01

    Radial velocities (RV) measured from near-infrared (NIR) spectra are a potentially excellent tool to search for extrasolar planets around cool or active stars. High resolution infrared (IR) spectrographs now available are reaching the high precision of visible instruments, with a constant improvement over time. GIANO is an infrared echelle spectrograph at the Telescopio Nazionale Galileo (TNG) and it is a powerful tool to provide high resolution spectra for accurate RV measurements of exoplanets and for chemical and dynamical studies of stellar or extragalactic objects. No other high spectral resolution IR instrument has GIANO's capability to cover the entire NIR wavelength range (0.95-2.45 μm) in a single exposure. In this paper we describe the ensemble of procedures that we have developed to measure high precision RVs on GIANO spectra acquired during the Science Verification (SV) run, using the telluric lines as wavelength reference. We used the Cross Correlation Function (CCF) method to determine the velocity for both the star and the telluric lines. For this purpose, we constructed two suitable digital masks that include about 2000 stellar lines, and a similar number of telluric lines. The method is applied to various targets with different spectral type, from K2V to M8 stars. We reached different precisions mainly depending on the H-magnitudes: for H ˜ 5 we obtain an rms scatter of ˜ 10 m s-1, while for H ˜ 9 the standard deviation increases to ˜ 50 ÷ 80 m s-1. The corresponding theoretical error expectations are ˜ 4 m s-1 and 30 m s-1, respectively. Finally we provide the RVs measured with our procedure for the targets observed during GIANO Science Verification.

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

    NASA Astrophysics Data System (ADS)

    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. Highly efficient Er-Yb codoped double-clad fiber amplifier with an Yb-band resonant cavity

    NASA Astrophysics Data System (ADS)

    Han, Qun; Yao, Yunzhi; Tang, Xiaoyun; Chen, Yaofei; Yan, Wenchuan; Liu, Tiegen; Song, Huiling

    2017-02-01

    A high-power Er-Yb codoped fiber amplifier (EYDFA) with an Yb-band resonant cavity is investigated. By introducing a linear resonant cavity formed by a pair of high-reflection double-clad fiber Bragg gratings, the Yb-ASE problem of high-power pumped EYDFAs can be resolved and the efficiency of the amplifier can be notably improved. At a pump power of ~17 W, an output power of 7.25 W was experimentally achieved. The pump conversion efficiency and slope efficiency relative to the applied pump power are ~42.6% and ~45.6%, respectively. Moreover, due to the gain-clamping effect of the Yb cavity, the gain flatness of the amplifier is also evidently improved.

  2. Note: Studies on x-ray production in electron cyclotron resonance x-ray source based on ridged cylindrical cavity

    SciTech Connect

    Selvakumaran, T. S.; Baskaran, R.

    2012-02-15

    A ridged cylindrical cavity has been designed using MICROWAVE STUDIO programme and it is used in the electron cyclotron resonance (ECR) x-ray source. The experimental parameters of the source are optimized for maximizing the x-ray output, and an x-ray dose rate of {approx}1000 {mu}Sv/h was observed at 20 cm from the port, for 500 W of microwave power without using any target. With the molybdenum target located at optimum position of the ridged cavity, the dose rate is found to be increased only by 10%. In order to understand the experimental observation, the electric field pattern of the cavity with the target placed at various radial distances is studied. In this note, the experimental and theoretical studies on ECR x-ray source using the ridged cylindrical cavity are presented.

  3. Modular Gravitational Reference Sensor for High Precision Astronomical Space Missions

    NASA Astrophysics Data System (ADS)

    Sun, Ke-Xun; Allen, G.; Buchman, S.; Byer, R. L.; Conklin, J. W.; DeBra, D. B.; Gill, D.; Goh, A.; Higuchi, S.; Lu, P.; Robertson, N.; Swank, A.

    2006-12-01

    We review the progress in developing the Modular Gravitational Reference Sensor (modular GRS) [1], which was first proposed as a simplified core sensor for space gravitational wave detection missions. In a modular GRS, laser beam from the remote the sensor does not illuminate the proof mass directly. The internal measurement from housing to proof mass is separated from the external interferometry. A double side grating may further simplify the structure and may better preserve the measurement precision. We review the recent progress in developing modular GRS at Stanford. We have further studied optical sensing design that combines advantage of high precision interferometric measurement and robust optical shadow sensing scheme. We have made critical progress in optical measurement of the center of mass position of a spherical proof mass at a precision without costing the dynamic range while spinning. We have successfully demonstrated the feasibility of fabricating localized grating pattern onto the dielectric and gold materials. We have conducted an initial experiment of rf heterodyne of cavity reflection and thus lowered optical power than that in the direct detection. We have further studied UV LED that will be used for AC charge management experiment. The modular GRS will be an in-time, cost effective product for the advanced Laser Interferometric Space Antenna (LISA) and the Big Bang Observatory (BBO). [1] K. Sun, G. Allen, S. Buchman, D. DeBra, and R. L. Byer, “Advanced Architecture for High Precision Space Laser Interferometers”, 5th International LISA Symposium, ESTEC, Noordwijk, The Netherlands, 12-16 July 2004. Class. Quantum Grav. 22 (2005) S287-S296.

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

    PubMed

    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.

  5. Highly Parallel, High-Precision Numerical Integration

    SciTech Connect

    Bailey, David H.; Borwein, Jonathan M.

    2005-04-22

    This paper describes a scheme for rapidly computing numerical values of definite integrals to very high accuracy, ranging from ordinary machine precision to hundreds or thousands of digits, even for functions with singularities or infinite derivatives at endpoints. Such a scheme is of interest not only in computational physics and computational chemistry, but also in experimental mathematics, where high-precision numerical values of definite integrals can be used to numerically discover new identities. This paper discusses techniques for a parallel implementation of this scheme, then presents performance results for 1-D and 2-D test suites. Results are also given for a certain problem from mathematical physics, which features a difficult singularity, confirming a conjecture to 20,000 digit accuracy. The performance rate for this latter calculation on 1024 CPUs is 690 Gflop/s. We believe that this and one other 20,000-digit integral evaluation that we report are the highest-precision non-trivial numerical integrations performed to date.

  6. High precision laser photometer for laser optics

    NASA Astrophysics Data System (ADS)

    Zhao, Yuan'an; Hu, Guohang; Cao, Zhen; Liu, Shijie; Zhu, Meiping; Shao, Jianda

    2017-06-01

    Development of laser systems requires optical components with high performance, and a high-precision double-beam laser photometer was designed and established to measure the optical performance at 1064nm. Double beam design and lock-in technique was applied to decrease the impact of light energy instability and electric noise. Pairs of samples were placed symmetrically to eliminate beam displacement, and laser scattering imaging technique was applied to determine the influence of surface defect on the optical performance. Based on the above techniques, transmittance and reflection of pairs of optics were obtained, and the measurement precision was improved to 0.06%. Different types of optical loss, such as total loss, volume loss, residual reflection and surface scattering loss, were obtained from the transmittance and reflection measurement of samples with different thickness. Comparison of optical performance of the test points with and without surface defects, the influence of surface defects on optical performance was determined. The optical performance of Nd-glass at 1064nm were measured as an example. Different types of optical loss and the influence of surface defects on the optical loss was determined.

  7. High precision innovative micropump for artificial pancreas

    NASA Astrophysics Data System (ADS)

    Chappel, E.; Mefti, S.; Lettieri, G.-L.; Proennecke, S.; Conan, C.

    2014-03-01

    The concept of artificial pancreas, which comprises an insulin pump, a continuous glucose meter and a control algorithm, is a major step forward in managing patient with type 1 diabetes mellitus. The stability of the control algorithm is based on short-term precision micropump to deliver rapid-acting insulin and to specific integrated sensors able to monitor any failure leading to a loss of accuracy. Debiotech's MEMS micropump, based on the membrane pump principle, is made of a stack of 3 silicon wafers. The pumping chamber comprises a pillar check-valve at the inlet, a pumping membrane which is actuated against stop limiters by a piezo cantilever, an anti-free-flow outlet valve and a pressure sensor. The micropump inlet is tightly connected to the insulin reservoir while the outlet is in direct communication with the patient skin via a cannula. To meet the requirement of a pump dedicated to closed-loop application for diabetes care, in addition to the well-controlled displacement of the pumping membrane, the high precision of the micropump is based on specific actuation profiles that balance effect of pump elasticity in low-consumption push-pull mode.

  8. High-precision laser machining of ceramics

    NASA Astrophysics Data System (ADS)

    Toenshoff, Hans K.; von Alvensleben, Ferdinand; Graumann, Christoph; Willmann, Guido

    1998-09-01

    The increasing demand for highly developed ceramic materials for various applications calls for innovative machining technologies yielding high accuracy and efficiency. Associated problems with conventional, i.e. mechanical methods, are unacceptable tool wear as well as force induced damages on ceramic components. Furthermore, the established grinding techniques often meet their limits if accurate complex 2D or 3D structures are required. In contrast to insufficient mechanical processes, UV-laser precision machining of ceramics offers not only a valuable technological alternative but a considerable economical aspect as well. In particular, excimer lasers provide a multitude of advantages for applications in high precision and micro technology. Within the UV wavelength range and pulses emitted in the nano-second region, minimal thermal effects on ceramics and polymers are observed. Thus, the ablation geometry can be controlled precisely in the lateral and vertical directions. In this paper, the excimer laser machining technology developed at the Laser Zentrum Hannover is explained. Representing current and future industrial applications, examinations concerning the precision cutting of alumina (Al2O3), and HF-composite materials, the ablation of ferrite ceramics for precision inductors and the structuring of SiC sealing and bearing rings are presented.

  9. High Precision Isotopic Reference Material Program

    NASA Astrophysics Data System (ADS)

    Mann, J. L.; Vocke, R. D.

    2007-12-01

    Recent developments in thermal ionization and inductively coupled plasma multicollector mass spectrometers have lead to "high precision" isotope ratio measurements with uncertainties approaching a few parts in 106. These new measurement capabilities have revolutionized the study of isotopic variations in nature by increasing the number of elements showing natural variations by almost a factor of two, and new research areas are actively opening up in climate change, health, ecology, geology and forensic studies. Because the isotopic applications are impacting very diverse fields, there is at present little effective coordination between research laboratories over reference materials and the values to apply to those materials. NIST had originally developed the techniques for producing accurate isotopic characterizations, culminating in the NIST Isotopic SRM series. The values on existing materials however are insufficiently precise and, in some cases, may be isotopically heterogeneous. A new generation of isotopic standards is urgently needed and will directly affect the quality and scope of emergent applications and ensure that the results being derived from these diverse fields are comparable. A series of new isotopic reference materials similar to the NIST 3100 single element solution series is being designed for this purpose and twelve elements have been selected as having the most pressing need. In conjunction with other expert users and National Metrology Institutes, an isotopic characterization of the respective 12 selected ampoules from the NIST single element solution series is currently underway. In this presentation the preliminary results of this screening will be discussed as well as the suitability of these materials in terms of homogeneity and purity, long term stability and availability, and isotopic relevance. Approaches to value assignment will also be discussed.

  10. High precision optical surface metrology using deflectometry

    NASA Astrophysics Data System (ADS)

    Huang, Run

    Software Configurable Optical Test System (SCOTS) developed at University of Arizona is a highly efficient optical metrology technique based on the principle of deflectometry, which can achieve comparable accuracy with interferometry but with low-cost hardware. In a SCOTS test, an LCD display is used to generate structured light pattern to illuminate the test optics and the reflected light is captured by a digital camera. The surface slope of test optics is determined by triangulation of the display pixels, test optics, and the camera. The surface shape is obtained by the integration of the slopes. Comparing to interferometry, which has long served as an accurate non-contact optical metrology technology, SCOTS overcomes the limitation of dynamic range and sensitivity to environment. It is able to achieve high dynamic range slope measurement without requiring null optics. In this dissertation, the sensitivity and performance of the test system have been analyzed comprehensively. Sophisticated calibrations of system components have been investigated and implemented in different metrology projects to push this technology to a higher accuracy including low-order terms. A compact on-axis SCOTS system lowered the testing geometry sensitivity in the metrology of 1-meter highly aspheric secondary mirror of Large Binocular Telescope. Sub-nm accuracy was achieved in testing a high precision elliptical X-ray mirror by using reference calibration. A well-calibrated SCOTS was successfully constructed and is, at the time of writing this dissertation, being used to provide surface metrology feedback for the fabrication of the primary mirror of Daniel K. Inouye Solar Telescope which is a 4-meter off-axis parabola with more than 8 mm aspherical departure.

  11. Fiber Scrambling for High Precision Spectrographs

    NASA Astrophysics Data System (ADS)

    Kaplan, Zachary; Spronck, J. F. P.; Fischer, D.

    2011-05-01

    The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called "super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the largest factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980's to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber's ability to produce an output beam independent of input. Our research is focused on characterizing the scrambling properties of several types of fibers, including circular, square and octagonal fibers. By measuring the intensity distribution after the fiber as a function of input beam position, we can simulate guiding errors that occur at an observatory. Through this, we can determine which fibers produce the most uniform outputs for the severest guiding errors, improving the PSF and allowing sub-m/s precision. However, extensive testing of fibers of supposedly identical core diameter, length and shape from the same manufacturer has revealed the "personality” of individual fibers. Personality describes differing intensity patterns for supposedly duplicate fibers illuminated identically. Here, we present our results on scrambling characterization as a function of fiber type, while studying individual fiber personality.

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

    SciTech Connect

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

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Heating properties of the re-entrant type cavity applicator for brain tumor with several resonant frequencies.

    PubMed

    Suzuki, M; Kato, K; Hirashima, T; Shindo, Y; Uzuka, T; Takahashi, H; Fujii, Y

    2009-01-01

    We have proposed the re-entrant resonant cavity applicator system for non-invasive brain tumor hyperthermia treatment. In this method, a human head is placed in the gap of the inner electrodes. A brain tumor is heated with the electromagnetic field stimulated in the cavity without contact between the human head and the applicator. We have already presented the effectiveness of the heating properties of this system with cylinder-type agar phantoms and by computer simulations. This paper discusses the heating properties of the developed system with the human head-type agar phantom for brain tumor hyperthermia treatment. First, in order to heat deep brain tumors, we tried to heat the human head-type agar phantom by using several electromagnetic field patterns of the resonant frequency. We found that the temperature distributions can be controlled inside the agar phantom by changing the resonant frequencies. Second, to heat local and deep areas of the agar phantom, we tried to achieve heating using the two different resonant frequencies. We found distinct heating properties by changing the electromagnetic field patterns of resonant frequencies. From these results, it was found that our developed heating system can be applied to hyperthermia treatments of deep-seated brain tumors. Further, by changing resonant frequency, treatment can very correspond to the size and the position of a tumor.

  17. Aerodynamic window for high precision laser drilling

    NASA Astrophysics Data System (ADS)

    Sommer, Steffen; Dausinger, Friedrich; Berger, Peter; Hügel, Helmuth

    2007-05-01

    High precision laser drilling is getting more and more interesting for industry. Main applications for such holes are vaporising and injection nozzles. To enhance quality, the energy deposition has to be accurately defined by reducing the pulse duration and thereby reducing the amount of disturbing melting layer. In addition, an appropriate processing technology, for example the helical drilling, yields holes in steel at 1 mm thickness and diameters about 100 μm with correct roundness and thin recast layers. However, the processing times are still not short enough for industrial use. Experiments have shown that the reduction of the atmospheric pressure down to 100 hPa enhances the achievable quality and efficiency, but the use of vacuum chambers in industrial processes is normally quite slow and thus expensive. The possibility of a very fast evacuation is given by the use of an aerodynamic window, which produces the pressure reduction by virtue of its fluid dynamic features. This element, based on a potential vortex, was developed and patented as out-coupling window for high power CO II lasers by IFSW 1, 2, 3. It has excellent tightness and transmission properties, and a beam deflection is not detectable. The working medium is compressed air, only. For the use as vacuum element for laser drilling, several geometrical modifications had to be realized. The prototype is small enough to be integrated in a micromachining station and has a low gas flow. During the laser pulse, which is focussed through the potential flow, a very high fluence is reached, but the measurements have not shown any beam deflection or focal shifting. The evacuation time is below 300 ms so that material treatment with changing ambient pressure is possible, too. Experimental results have proven the positive effect of the reduced ambient pressure on the drilling process for the regime of nano- and picosecond laser pulses. Plasma effects are reduced and, because of the less absorption, the

  18. Tunable resonant-cavity-enhanced photodetector with double high-index-contrast grating mirrors

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    In this paper, we propose a broadband-tunable resonant-cavity-enhanced photodetector (RCE-PD) structure with double high-index-contrast grating (HCG) mirrors and numerically investigate its characteristics. The detector is designed to operate at 1550-nm wavelength. The detector structure consists of a top InP HCG mirror, a p-i-n photodiode embedding multiple quantum wells, and a Si HCG mirror formed in the Si layer of a silicon-on-insulator wafer. The detection wavelength can be changed by moving the top InP HCG mirror suspended in the air. High reflectivity and small penetration length of HCGs lead to a narrow absorption linewidth of 0.38 nm and a broad tuning range of 111 nm. The peak absorption efficiency is 76-84% within the tuning range. This broadband-tunable and narrow-absorption-linewidth RCE-PD is desirable for applications where selective wavelength demultiplexing is required. Furthermore, the fact that it can be fabricated on a silicon platform offers us a possibility of integration with electronics.

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

    PubMed

    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 < 0.05) among the means of optical absorption coefficient data for the folding degree and fruit type in citrus oils. The experimental results show that TWRC-PPE spectroscopy can be used to quantify concentrations up to five times higher of total carotenoids and chlorophylls in citrus oils than UV-Vis spectroscopy without sample preparation or dilution. The optical limits of this technique and possible interference are also described. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Origin of power fluctuations in GaN resonant-cavity light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Roycroft, Brendan; Akhter, Mahbub; Maaskant, Pleun; Corbett, Brian; Shaw, Alan; Bradley, Louise; de Mierry, Phillipe; Poisson, Marie-Antoinette

    2004-03-01

    Resonant-cavity light-emitting diodes (RCLEDs) with multiple InGaN/GaN quantum wells have been grown on sapphire substrates. The emission was through the substrate, and the top contact consisted of a highly reflecting Pd/Ag metallization. The peak emission wavelength was measured to be 490 nm. Under constant current biasing, the intensity was observed to fluctuate irregularly accompanied by correlated variations in the voltage. To investigate this further, emission from the RCLED was focused through a GaAs wafer onto a Vidicon camera. This gave a series of infrared, near-field images, spectrally integrated over a wavelength range from 870 nm to 1.9 μm. Flashes from point sources on the RCLED surface were observed, indicating that short-lived, highly localized "hot spots" were being formed that generated pulses of thermal radiation. It is proposed that this phenomenon results from the migration of metal into nanopipes present in this material. The filled pipes form short circuits that subsequently fuse and are detected by bursts of infrared radiation that are recorded in real time.

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

    SciTech Connect

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

    2016-06-28

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

  2. Thermal-wave resonator cavity design and measurements of the thermal diffusivity of liquids

    NASA Astrophysics Data System (ADS)

    Balderas-López, J. A.; Mandelis, A.; Garcia, J. A.

    2000-07-01

    A liquid-ambient-compatible thermal wave resonant cavity (TWRC) has been constructed for the measurement of the thermal diffusivity of liquids. The thermal diffusivities of distilled water, glycerol, ethylene glycol, and olive oil were determined at room temperature (25 °C), with four-significant-figure precision as follows: (0.1445±0.0002)×10-2 cm2/s (distilled water); (0.0922±0.0002)×10-2 cm2/s (glycerol); (0.0918±0.0002)×10-2 cm2/s (ethylene glycol); and (0.0881±0.0004)×10-2 cm2/s (olive oil). The liquid-state TWRC sensor was found to be highly sensitive to various mixtures of methanol and salt in distilled water with sensitivity limits 0.5% (v/v) and 0.03% (w/v), respectively. The use of the TWRC to measure gas evolution from liquids and its potential for environmental applications has also been demonstrated.

  3. Temperature sensor based on a hybrid ITO-silica resonant cavity

    PubMed Central

    Socorro, Abian B.; Soltani, Soheil; Del Villar, Ignacio; Corres, Jesus M.; Armani, Andrea M.

    2015-01-01

    Integrated optical devices comprised of multiple material systems are able to achieve unique performance characteristics, enabling applications in sensing and in telecommunications. Due to ease of fabrication, the majority of previous work has focused on polymer-dielectric or polymer-semiconductor systems. However, the environmental stability of polymers is limited. In the present work, a hybrid device comprised of an indium tin oxide (ITO) coating on a silicon dioxide toroidal resonant cavity is fabricated. Finite element method simulations of the optical field in the multi-material device are performed, and the optical mode profile is significantly altered by the high index film. The quality factor is also measured and is material loss limited. Additionally, its performance as a temperature sensor is characterized. Due to the high thermo-optic coefficient of ITO and the localization of the optical field in the ITO layer, the hybrid temperature sensor demonstrates a nearly 3-fold improvement in performance over the conventional silica device. PMID:25836065

  4. A Novel Micro- and Nano-Scale Positioning Sensor Based on Radio Frequency Resonant Cavities

    PubMed Central

    Asua, Estibaliz; Etxebarria, Victor; García-Arribas, Alfredo; Feutchwanger, Jorge; Portilla, Joaquín; Lucas, Julio

    2014-01-01

    In many micro- and nano-scale technological applications high sensitivity displacement sensors are needed, especially in ultraprecision metrology and manufacturing. In this work a new way of sensing displacement based on radio frequency resonant cavities is presented and experimentally demonstrated using a first laboratory prototype. The principle of operation of the new transducer is summarized and tested. Furthermore, an electronic interface that can be used together with the displacement transducer is designed and proved. It has been experimentally demonstrated that very high and linear sensitivity characteristic curves, in the range of some kHz/nm; are easily obtainable using this kind of transducer when it is combined with a laboratory network analyzer. In order to replace a network analyzer and provide a more affordable, self-contained, compact solution, an electronic interface has been designed, preserving as much as possible the excellent performance of the transducer, and turning it into a true standalone positioning sensor. The results obtained using the transducer together with a first prototype of the electronic interface built with cheap discrete elements show that positioning accuracies in the micrometer range are obtainable using this cost-effective solution. Better accuracies would also be attainable but using more involved and costly electronics interfaces. PMID:24887041

  5. A novel micro- and nano-scale positioning sensor based on radio frequency resonant cavities.

    PubMed

    Asua, Estibaliz; Etxebarria, Victor; García-Arribas, Alfredo; Feutchwanger, Jorge; Portilla, Joaquín; Lucas, Julio

    2014-05-30

    In many micro- and nano-scale technological applications high sensitivity displacement sensors are needed, especially in ultraprecision metrology and manufacturing. In this work a new way of sensing displacement based on radio frequency resonant cavities is presented and experimentally demonstrated using a first laboratory prototype. The principle of operation of the new transducer is summarized and tested. Furthermore, an electronic interface that can be used together with the displacement transducer is designed and proved. It has been experimentally demonstrated that very high and linear sensitivity characteristic curves, in the range of some kHz/nm; are easily obtainable using this kind of transducer when it is combined with a laboratory network analyzer. In order to replace a network analyzer and provide a more affordable, self-contained, compact solution, an electronic interface has been designed, preserving as much as possible the excellent performance of the transducer, and turning it into a true standalone positioning sensor. The results obtained using the transducer together with a first prototype of the electronic interface built with cheap discrete elements show that positioning accuracies in the micrometer range are obtainable using this cost-effective solution. Better accuracies would also be attainable but using more involved and costly electronics interfaces.

  6. Energy-localization-enhanced ground-state cooling of a mechanical resonator from room temperature in optomechanics using a gain cavity

    NASA Astrophysics Data System (ADS)

    Liu, Yu-Long; Liu, Yu-xi

    2017-08-01

    When a gain system is coupled to a loss system, the energy usually flows from the gain system to the loss one. We here present a counterintuitive theory for the ground-state cooling of a mechanical resonator in an optomechanical system via a gain cavity. The energy flows first from the mechanical resonator into the loss cavity and then into the gain cavity and finally localizes there. The energy localization in the gain cavity dramatically enhances the cooling rate of the mechanical resonator. Moreover, we show that an unconventional optical spring effect, e.g., a giant frequency shift and optically induced damping of the mechanical resonator, can be realized. Those feature a precooling-free ground-state cooling, i.e., the mechanical resonator in thermal excitation at room temperature can directly be cooled to its ground state. This cooling approach has potential application in fundamental tests of quantum physics without complicated cryogenic setups.

  7. HIGH PRECISION ROVIBRATIONAL SPECTROSCOPY OF OH{sup +}

    SciTech Connect

    Markus, Charles R.; Hodges, James N.; Perry, Adam J.; Kocheril, G. Stephen; McCall, Benjamin J.; Müller, Holger S. P.

    2016-02-01

    The molecular ion OH{sup +} has long been known to be an important component of the interstellar medium. Its relative abundance can be used to indirectly measure cosmic ray ionization rates of hydrogen, and it is the first intermediate in the interstellar formation of water. To date, only a limited number of pure rotational transitions have been observed in the laboratory making it necessary to indirectly calculate rotational levels from high-precision rovibrational spectroscopy. We have remeasured 30 transitions in the fundamental band with MHz-level precision, in order to enable the prediction of a THz spectrum of OH{sup +}. The ions were produced in a water cooled discharge of O{sub 2}, H{sub 2}, and He, and the rovibrational transitions were measured with the technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy. These values have been included in a global fit of field free data to a {sup 3}Σ{sup −} linear molecule effective Hamiltonian to determine improved spectroscopic parameters which were used to predict the pure rotational transition frequencies.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Dielectric properties of dates at 2.45 GHz determined with a tunable single-mode resonant cavity.

    PubMed

    Ali, I A; al-Amri, A M; Dawoud, M M

    2000-01-01

    A tunable TM012-mode resonant cavity with an additional tuning mechanism and working at 2.45 GHz has been designed, fabricated and tested for determination of dielectric properties of dates. The cavity has a Q-factor > 5000, and a tuning mechanism which gives it more flexibility and controllability. The cavity has been used for determining the dielectric properties of Rezaiz, the most common type of dates used in the production of data juice in the Eastern Province of the Kingdom of Saudi Arabia. The dielectric constant for this type of dates was 4.6 +/- 0.16, and the loss factor was 0.21 +/- 0.03, at 8.75% moisture. These results are comparable with the dielectric properties of some other fruits, of similar composition, at the same moisture level.

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

    NASA Astrophysics Data System (ADS)

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

    2017-06-01

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

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

    PubMed Central

    Zhang, Zhidong; Luo, Liang; Xue, Chenyang; Zhang, Wendong; Yan, Shubin

    2016-01-01

    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. PMID:27164101

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

    PubMed

    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.

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

    PubMed Central

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

    2016-01-01

    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. PMID:27999254

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

    SciTech Connect

    Dantan, A.; Marler, J. P.; Albert, M.; Guenot, D.; Drewsen, M.

    2010-09-03

    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.

  15. Research on the high-precision non-contact optical detection technology for banknotes

    NASA Astrophysics Data System (ADS)

    Jin, Xiaofeng; Liang, Tiancai; Luo, Pengfeng; Sun, Jianfeng

    2015-09-01

    The technology of high-precision laser interferometry was introduced for optical measurement of the banknotes in this paper. Taking advantage of laser short wavelength and high sensitivity, information of adhesive tape and cavity about the banknotes could be checked efficiently. Compared with current measurement devices, including mechanical wheel measurement device, Infrared measurement device, ultrasonic measurement device, the laser interferometry measurement has higher precision and reliability. This will improve the ability of banknotes feature information in financial electronic equipment.

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

    DTIC Science & Technology

    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

  17. X-ray free-electron laser oscillator with nuclear-resonant cavity stabilization and quantum-optical applications

    SciTech Connect

    Adams, Bernhard W.; Kim, Kwang -Je

    2016-08-09

    Here, x-ray free-electron-laser oscillators with nuclear-resonant cavity stabilization (NRS-XFELO) hold the promise for providing x-rays with unprecedented coherence properties that will enable interesting quantum-optical and metrological applications. Among these are atom optics with x-ray-based optical elements providing high momentum transfer, or a frequency standard far surpassing the best state-of the-art atomic clocks.

  18. Efficient phase noise suppression of an external-cavity diode-laser by optical filtering and resonant optical feedback

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Miyakawa, S.; Kasai, K.; Okada-Shudo, Y.; Watanabe, M.

    2012-07-01

    We experimentally demonstrated that the excess phase noise of an external cavity diode laser (ECDL) can be efficiently suppressed by optical filtering and resonant optical feedback techniques. A suppression of more than 40 dB phase noise was obtained for the first time using these methods. It made that the phase noise of the ECDL reached shot noise level from 15 MHz. This opens a new way to reduce the phase noise of diode lasers.

  19. Exploiting concave-convex linear resonators to design end-pumped solid-state lasers with flexible cavity lengths: Application for exploring the self-mode-locked operation.

    PubMed

    Tuan, P H; Chang, C C; Lee, C Y; Cho, C Y; Liang, H C; Chen, Y F

    2016-11-14

    The characteristics of a convex-concave linear resonator under the thermal lensing effect are theoretically analyzed to find an analytical model for designing end-pumped solid-state lasers with flexible cavity lengths. By exploiting the design model, the power scaling for continuous-wave operation under strong thermal lensing can be easily achieved in the proposed resonator with different cavity lengths. Furthermore, the proposed resonator is applied to explore the exclusive influence of cavity length on the self-mode-locked (SML) operation. It is discovered that the lasing longitudinal modes will split into multiple groups in optical spectrum to lead to a multi-pulse mode-locked temporal state when the cavity length increases. Finally, a theoretical model is derived to reconstruct the experimental results of SML operation to deduce a simple relationship between the group number of lasing modes and the cavity length.

  20. Resonant cavity mode dependence of anomalous and inverse spin Hall effect

    SciTech Connect

    Kim, Sang-Il; Seo, Min-Su; Park, Seung-young

    2014-05-07

    The direct current electric voltage induced by the Inverse Spin Hall Effect (ISHE) and Anomalous Hall Effect (AHE) was investigated in the TE{sub 011} and TE{sub 102} cavities. The ISHE and AHE components were distinguishable through the fitting of the voltage spectrum. The unwanted AHE was minimized by placing the DUT (Device Under Test) at the center of both the TE{sub 011} and TE{sub 102} cavities. The voltage of ISHE in the TE{sub 011} cavity was larger than that in the TE{sub 102} cavity due to the higher quality factor of the former. Despite optimized centering, AHE voltage from TE{sub 011} cavity was also higher. The reason was attributed to the E-field distribution inside the cavity. In the case of the TE{sub 011} cavity, the DUT was easily exposed to the E-field in all directions. Therefore, the parasitic AHE voltage in the TE{sub 102} cavity was less sensitive than that in the TE{sub 011} cavity to decentering problem.

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

    PubMed

    Kim, Jun Ho; Park, Sun-Won; Kim, Soo Chin; Lim, Myung Kwan; Jang, Tae Young; Kim, Yeo Ju; Kang, Young Hye; Lee, Ha Young

    2015-01-01

    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.

  2. Computed Tomography and Magnetic Resonance Imaging Findings of Nasal Cavity Hemangiomas According to Histological Type

    PubMed Central

    Kim, Jun Ho; Kim, Soo Chin; Lim, Myung Kwan; Jang, Tae Young; Kim, Yeo Ju; Kang, Young Hye; Lee, Ha Young

    2015-01-01

    Objective 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). Materials and Methods 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. Results 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. Conclusion 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. PMID:25995686

  3. Towards high precision measurements of nuclear g-factors for the Be isotopes

    NASA Astrophysics Data System (ADS)

    Takamine, A.; Wada, M.; Okada, K.; Ito, Y.; Schury, P.; Arai, F.; Katayama, I.; Imamura, K.; Ichikawa, Y.; Ueno, H.; Wollnik, H.; Schuessler, H. A.

    2016-06-01

    We describe the present status of future high-precision measurements of nuclear g-factors utilizing laser-microwave double and laser-microwave-rf triple resonance methods for online-trapped, laser-cooled radioactive beryllium isotope ions. These methods have applicability to other suitably chosen isotopes and for beryllium show promise in deducing the hyperfine anomaly of 11Be with a sufficiently high precision to study the nuclear magnetization distribution of this one-neutron halo nucleus in a nuclear-model-independent manner.

  4. A resonance shift prediction based on the Boltzmann-Ehrenfest principle for cylindrical cavities with a rigid sphere.

    PubMed

    Santillan, Arturo O; Cutanda-Henríquez, Vicente

    2008-11-01

    An investigation on the resonance frequency shift for a plane-wave mode in a cylindrical cavity produced by a rigid sphere is reported in this paper. This change of the resonance frequency has been previously considered as a cause of oscillational instabilities in single-mode acoustic levitation 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 literature. The position of the sphere can be any point along the axis of the cavity. Obtained predictions of the resonance frequency shift with the deduced equation agree quite well with numerical simulations based on the boundary element method. The results are also confirmed by experiments. The equation derived from the Boltzmann-Ehrenfest principle appears to be more general, and for large spheres, it gives a better approximation than the equation previously reported.

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

    NASA Astrophysics Data System (ADS)

    Stockklauser, A.; Scarlino, P.; Koski, J. V.; Gasparinetti, S.; Andersen, C. K.; Reichl, C.; Wegscheider, W.; Ihn, T.; Ensslin, K.; Wallraff, A.

    2017-01-01

    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 2 g /2 π =238 MHz at a resonator linewidth κ /2 π =12 MHz and a DQD charge qubit decoherence rate of γ2/2 π =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.

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

    PubMed

    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.

  7. Microwave plasma generation by the fast rotation and slow pulsation of resonant fields in a cylindrical cavity

    NASA Astrophysics Data System (ADS)

    Hasegawa, Yuichi; Nakamura, Keiji; Lubomirsky, Dima; Park, Soonam; Kobayashi, Satoru; Sugai, Hideo

    2017-04-01

    A digitally controlled solid-state microwave generator allowing variable frequency operation and precise phase control is adopted for plasma generation. In this study, a resonant cylindrical cavity is used as a microwave applicator in place of conventional waveguides. In order to improve the plasma uniformity, the TE111 mode is agitated by injecting microwaves into the cavity from two spatially orthogonal directions, with a temporal phase difference ϕ. Theoretical analyses and finite-difference time-domain simulations derive the following effects of the phase control. In the case of ϕ = ±π/2, fast rotation of the cavity field takes place with a rotational frequency of ω/2π (= 2.4-2.5 GHz), where ω denotes the microwave angular frequency. On the other hand, when ϕ is linearly modulated in time with a low frequency of Ω/2π (= 0.1-1000 Hz), slow pulsation takes place, in which the cavity field alternately excites a circular rotation and a standing oscillation at the modulation frequency. These effects are experimentally confirmed in microwave discharges in argon at 0.1-20 Torr with total injection powers from 50 to 800 W. Two-dimensional images of the optical emission from the generated plasma show that both the fast rotation and slow pulsation improve azimuthal plasma uniformity.

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

    PubMed

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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 (94GHz) cylindrical cavity is designed where modulation slots are optimized to present a uniform 100kHz field modulation over the length of the sample. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Semi-monolithic cavity for external resonant frequency doubling and method of performing the same

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid (Inventor)

    1999-01-01

    The fabrication of an optical cavity for use in a laser, in a frequency doubling external cavity, or any other type of nonlinear optical device, can be simplified by providing the nonlinear crystal in combination with a surrounding glass having an index of refraction substantially equal to that of the nonlinear crystal. The closed optical path in this cavity is formed in the surrounding glass and through the nonlinear crystal which lies in one of the optical segments of the light path. The light is transmitted through interfaces between the surrounding glass in the nonlinear crystal through interfaces which are formed at the Brewster-angle to minimize or eliminate reflection.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  14. Efficient continuous-wave eye-safe region signal output from intra-cavity singly resonant optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Li, Bin; Ding, Xin; Sheng, Quan; Yin, Su-Jia; Shi, Chun-Peng; Li, Xue; Yu, Xuan-Yi; Wen, Wu-Qi; Yao, Jian-Quan

    2012-01-01

    We report an efficient continuous-wave (CW) tunable intra-cavity singly resonant optical parametric oscillator based on the multi-period periodically poled lithium niobate and using a laser diode (LD) end-pumped CW 1064 nm Nd:YVO4 laser as the pump source. A highly efficiency CW operation is realized through a careful cavity design for mode matching and thermal stability. The signal tuning range is 1401-1500 nm obtained by varying the domain period. The maximum output power of 2.2 W at 1500 nm is obtained with a 17.1 W 808 nm LD power and the corresponding conversion efficiency is 12.9%.

  15. Fabrication and characterization of the Si-photonics-integrated vertical resonant-cavity light-emitting diode

    NASA Astrophysics Data System (ADS)

    Kong, Duanhua; Kim, Taek; Kim, Sihan; Hong, Hyungi; Shcherbatko, Igor; Park, Youngsoo; Shin, Dongjae; Ha, Kyoung-Ho; Jeong, Gitae

    2014-03-01

    We designed and fabricated a 1.3-um hybrid vertical Resonant-Cavity Light-Emitting Diode for optical interconnect by using direct III-V wafer bonding on silicon on insulator (SOI). The device included InP based front distributed Bragg reflector (DBR), InGaAlAs based active layer, and SOI-based high-contrast-grating (HCG) as a back reflector. 42-uW continuous wave optical power was achieved at 20mA at room temperature.

  16. High-precision photometry of WASP-12 b transits

    NASA Astrophysics Data System (ADS)

    Maciejewski, G.; Errmann, R.; Raetz, St.; Seeliger, M.; Spaleniak, I.; Neuhäuser, R.

    2011-04-01

    Aims: The transiting extrasolar planet WASP-12 b was found to be one of the most intensely irradiated exoplanets. It is unexpectedly bloated and is losing mass that may accrete into the host star. Our aim was to refine the parameters of this intriguing system and search for signs of transit timing variations. Methods: We gathered high-precision light curves for two transits of WASP-12 b. Assuming various limb-darkening laws, we generated best-fitting models and redetermined the parameters of the system. Error estimates were derived by the prayer-bead method and Monte Carlo simulations. Results: System parameters obtained by us are found to agree with previous studies within one sigma. Use of the non-linear limb-darkening laws results in the best-fitting models. With two new mid-transit times, the ephemeris was refined to BJDTDB = (2 454 508.97682 ± 0.00020) + (1.09142245 ± 0.00000033)E. Interestingly, indications of transit timing variation are detected at the level of 3.4 sigma. This signal can be induced by an additional planet in the system. Simplified numerical simulations show that a perturber could be a terrestrial-type planet if both planets are in a low-order orbital resonance. However, we emphasise that further observations are needed to confirm variation and to constrain properties of the perturber. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA), operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofisica de Andalucia (CSIC).Photometric data are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/528/A65

  17. Cavity-enhanced resonant photoacoustic spectroscopy with optical feedback cw diode lasers: A novel technique for ultratrace gas analysis and high-resolution spectroscopy.

    PubMed

    Hippler, Michael; Mohr, Christian; Keen, Katherine A; McNaghten, Edward D

    2010-07-28

    Cavity-enhanced resonant photoacoustic spectroscopy with optical feedback cw diode lasers (OF-CERPAS) is introduced as a novel technique for ultratrace gas analysis and high-resolution spectroscopy. In the scheme, a single-mode cw diode laser (3 mW, 635 nm) is coupled into a high-finesse linear cavity and stabilized to the cavity by optical feedback. Inside the cavity, a build-up of laser power to at least 2.5 W occurs. Absorbing gas phase species inside the cavity are detected with high sensitivity by the photoacoustic effect using a microphone embedded in the cavity. To increase sensitivity further, coupling into the cavity is modulated at a frequency corresponding to a longitudinal resonance of an organ pipe acoustic resonator (f=1.35 kHz and Q approximately 10). The technique has been characterized by measuring very weak water overtone transitions near 635 nm. Normalized noise-equivalent absorption coefficients are determined as alpha approximately 4.4x10(-9) cm(-1) s(1/2) (1 s integration time) and 2.6x10(-11) cm(-1) s(1/2) W (1 s integration time and 1 W laser power). These sensitivities compare favorably with existing state-of-the-art techniques. As an advantage, OF-CERPAS is a "zero-background" method which increases selectivity and sensitivity, and its sensitivity scales with laser power.

  18. Cavity-enhanced resonant photoacoustic spectroscopy with optical feedback cw diode lasers: A novel technique for ultratrace gas analysis and high-resolution spectroscopy

    NASA Astrophysics Data System (ADS)

    Hippler, Michael; Mohr, Christian; Keen, Katherine A.; McNaghten, Edward D.

    2010-07-01

    Cavity-enhanced resonant photoacoustic spectroscopy with optical feedback cw diode lasers (OF-CERPAS) is introduced as a novel technique for ultratrace gas analysis and high-resolution spectroscopy. In the scheme, a single-mode cw diode laser (3 mW, 635 nm) is coupled into a high-finesse linear cavity and stabilized to the cavity by optical feedback. Inside the cavity, a build-up of laser power to at least 2.5 W occurs. Absorbing gas phase species inside the cavity are detected with high sensitivity by the photoacoustic effect using a microphone embedded in the cavity. To increase sensitivity further, coupling into the cavity is modulated at a frequency corresponding to a longitudinal resonance of an organ pipe acoustic resonator (f =1.35 kHz and Q ≈10). The technique has been characterized by measuring very weak water overtone transitions near 635 nm. Normalized noise-equivalent absorption coefficients are determined as α ≈4.4×10-9 cm-1 s1/2 (1 s integration time) and 2.6×10-11 cm-1 s1/2 W (1 s integration time and 1 W laser power). These sensitivities compare favorably with existing state-of-the-art techniques. As an advantage, OF-CERPAS is a "zero-background" method which increases selectivity and sensitivity, and its sensitivity scales with laser power.

  19. Terahertz microfluidic sensor based on a parallel-plate waveguide resonant cavity

    NASA Astrophysics Data System (ADS)

    Mendis, Rajind; Astley, Victoria; Liu, Jingbo; Mittleman, Daniel M.

    2009-10-01

    We describe a terahertz optical resonator that is ideally suited for highly sensitive and noninvasive refractive-index monitoring. The resonator is formed by machining a rectangular groove into one plate of a parallel-plate waveguide, and is excited using the lowest-order transverse-electric (TE1) waveguide mode. Since the resonator can act as a channel for fluid flow, it can be easily integrated into a microfluidics platform for real-time monitoring. Using this resonator with only a few microliters of liquid, we demonstrate a refractive-index sensitivity of 3.7×105 nm/refractive-index-unit, the highest ever reported in any frequency range.

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

    DOE PAGES

    Zhao, Xin; Ciovati, G.; Bieler, T. R.

    2010-12-15

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

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

    SciTech Connect

    Zhao, Xin; Ciovati, G.; Bieler, T. R.

    2010-12-15

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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Lin, Tong; Chau, Fook Siong; Zhou, Guangya; Deng, Jie

    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.

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

    PubMed

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

    2017-01-01

    We experimentally realize an optical fiber ring resonator that includes a tapered section with a 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 the 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.

  5. Triple-Resonant Brillouin Light Scattering in Magneto-Optical Cavities

    NASA Astrophysics Data System (ADS)

    Haigh, J. A.; Nunnenkamp, A.; Ramsay, A. J.; Ferguson, A. J.

    2016-09-01

    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 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 wave vector 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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    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.

  7. HIgh-Q Optical Micro-cavity Resonators as High Sensitive Bio-chemical and Ultrasonic Sensors

    NASA Astrophysics Data System (ADS)

    Ling, Tao

    Optical micro-cavity resonators have quickly emerged in the past few years as a new sensing platform in a wide range of applications, such as bio-chemical molecular detection, environmental monitoring, acoustic and electromagnetic waves detection. In this thesis, we will mainly focus on developing high sensitivity silica micro-tube resonator bio-chemical sensors and high sensitivity polymer micro-ring resonator acoustic sensors. In high sensitivity silica micro-tube resonator bio-chemical sensors part: We first demonstrated a prism coupled silica micro-tube bio-chemical sensing platform to overcome the reliability problem in a fiber coupled thin wall silica micro-tube sensing platform. In refractive index sensing experiment, a unique resonance mode with sensitivity around 600nm/refractive index unit (RIU) has been observed. Surface sensing experiments also have been performed in this platform to detect lipid monolayer, lipid bilayer, electrostatic self assemble layer-by-layer as well as the interaction between the lipid bilayer and proteins. Then a theoretical study on various sensing properties on the silica micro-tube based sensing platform has been realized. Furthermore, we have proposed a coupled cavity system to further enhance the device's sensitivity above 1000nm/RIU. In high sensitivity polymer micro-ring resonator acoustic sensors part: We first presented a simplified fabrication process and realized a polymer microring with a Q factor around 6000. The fabricated device has been used to detect acoustic wave with noise equivalent pressure (NEP) around 230Pa over 1-75MHz frequency rang, which is comparable to state-of-art piezoelectric transducer and the device's frequency response also have been characterized to be up to 90MHz. A new fabrication process combined with resist reflow and thermal oxidation process has been used to improve the Q factor up to 10 5 and the device's NEP has been tested to be around 88Pa over 1-75MHz range. Further improving the

  8. Second-harmonic generation of a continuous-wave diode-pumped Nd:YAG laser using and externally resonant cavity

    SciTech Connect

    Kozlovsky, W.J.; Nabors, C.D.; Byer, R.L.

    1987-12-01

    We report 13% second-harmonic conversion efficiency of a 15-mW, cw, diode-laser-pumped Nd:YAG oscillator. 2 mW of single-axial-mode 532-mm radiation was generated by externally resonant second-harmonic generation in a monolithic MgO:LiNbO/sub 3/ nonlinear crystal cavity. The measured finesse of 450 for the monolithic external cavity indicated that absorption and scatter losses in the doubler were less than 0.8%.

  9. Monolayer rigid arrays of cavity-controllable metallic mesoparticles: Electrochemical preparation and light transmission resonances

    NASA Astrophysics Data System (ADS)

    Chen, Zhuo; Dong, Han; Pan, Jian; Zhan, Peng; Tang, Chaojun; Wang, Zhen-Lin

    2010-02-01

    We report an efficient and robust electrochemical deposition method to fabricate large-scale two-dimensional rigid arrays of metal colloids with a precise control of the particle morphology by monitoring metal growth that is confined within a templated organic porous mold. Light transmission resonances through the metallic periodic microstructures are observed and the resonance wavelengths are found to depend on the morphology of the scattering elements. Further numerical simulations confirm these transmission resonances and reveal that they are attributed to the excitations of localized or propagating surface plasmon modes supported by the specific structures. The present method of tailoring metallic microstructures could find applications in plasmonics.

  10. High-efficiency frequency upconversion of 1.5 μm laser based on a doubly resonant external ring cavity with a low finesse for signal field

    NASA Astrophysics Data System (ADS)

    Tan, Wei; Qiu, Xiaodong; Zhao, Gang; Jia, Mengyuan; Ma, Weiguang; Yan, Xiaojuan; Dong, Lei; Zhang, Lei; Tong, Zhaomin; Yin, Wangbao; Feng, Xiaoxia; Xiao, Liantuan; Axner, Ove; Jia, Suotang

    2017-02-01

    A doubly resonant external ring cavity with a low finesse for the signal field is used to improve the frequency upconversion efficiency of a weak 1583 nm signal laser to 636 nm by mixing with a resonance power enhanced 1064 nm pump laser in a 25 mm periodically poled lithium niobate crystal. The process of frequency upconversion is described and optimized by the doubly resonant cavity-enhanced sum frequency generation theory under the condition of undepleted pump approximation. By selecting the suitable reflectivity of the signal input mirror and the incident pump power, a cavity-enhanced frequency conversion efficiency of 94.6% was obtained for signal powers up to 25 mW with an input pump power of 780 mW.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Li, Xuefeng; Cao, Guangzhan; Liu, Hongjun

    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.

  13. High-efficiency acousto-optic coupling in phoxonic resonator based on silicon fishbone nanobeam cavity.

    PubMed

    Chiu, Chien-Chang; Chen, Wei-Min; Sung, Kuen-Wei; Hsiao, Fu-Li

    2017-03-20

    We investigate the acousto-optic coupling rates between different acoustic resonance modes and a specified optical resonance mode in a one-dimensional phoxonic crystal fishbone nanobeam formed by periodically arranging semi-cylinders of air on both sides of a suspended silicon waveguide. The gradually tapered unit cells form optical and acoustic resonators. In acousto-optic coupling rate calculation, the acoustic fields and optical fields are obtained by steady state monochromatic analysis and eigen-mode computation, respectively. Results showed that the acoustic polarizations and symmetries of the acoustic resonance modes are dominant factors in the acousto-optic coupling efficiency, and appropriate selection of these parameters can prevent cancellation of acousto-optic interactions, thereby enhancing acousto-optic coupling rates. This study provides important insights that can be applied to acousto-optic device designs.

  14. Resonances in the Earth-ionosphere cavity according to the data of magnetic observations in Tomsk

    NASA Astrophysics Data System (ADS)

    Kolesnik, S. A.; Kolmakov, A. A.; Nedosekov, D. A.

    2014-11-01

    The article describes magnetic measurements technique of natural electromagnetic fields in ELF range. The analysis results of the amplitude characteristics of the Schumann resonance modes in a suburban area in the seasonal cycle of observations is presented.

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

    DTIC Science & Technology

    2011-03-01

    longitudinal vibrational modes of the cavity are com- pared to the results from the WICS wind tunnel test . The CFD derived store pressure, force, and...the weapon bay. Suppression devices were developed as a result which served to quell the turbulent airflow and hence the vibrations in the bay. As...The data can come either from wind- tunnel testing or from computational fluid dynamics (CFD). The results from this analysis dictate which release

  16. Ray-mode analysis of complex resonances of an open cavity

    NASA Astrophysics Data System (ADS)

    Heyman, Ehud; Friedlander, Gershon; Felsen, Leopold B.

    1989-05-01

    An important class of targets involves open-ended enclosures with exterior-interior coupling. If the interior has waveguide-like properties, modal expansions can model the wave phenomena there, while ray methods can be utilized to account for multiple diffraction at the aperture edges, and for wave interactions aound the exterior boundary. By self-consistent ray-mode coupling in a hybrid format, it is possible to construct a global resonance equation whose solutions yield the complex resonant frequencies for the composite object. The conglomerate of these full resonances can be better understood by consideration of more easily determined partial resonances, which account for the dominant wave interactions in various frequency intervals. Such partial resonances can be generated by ignoring intermode coupling, external low-Q interactions, etc. These concepts are illustrated here on the prototype configuration of a finite-length plane parallel perfectly conducting waveguide, which is open at one end and terminated at the other. Emphasis is on the lower-order resonances where wavelengths are comparable to critical target dimensions.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed Central

    Howe, M. S.; McGowan, R. S.

    2011-01-01

    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. PMID:21666824

  1. Rigorous electromagnetic analysis of dipole emission in periodically corrugated layers: the grating-assisted resonant-cavity light-emitting diode.

    PubMed

    Delbeke, Danaë; Bienstman, Peter; Bockstaele, Ronny; Baets, Roel

    2002-05-01

    We study the grating-assisted light-emitting diode, an LED design for high brightness based on a resonant cavity containing one- or two-dimensionally periodically corrugated layers (grating). We give in detail a generally applicable electromagnetic analysis based on the rigorous coupled-wave theory to calculate the extraction efficiency of spontaneous emission in a periodically corrugated layer structure. This general model is then specified on the grating-assisted resonant-cavity LED, showing simulated efficiencies of more than 40%.

  2. High precision spectroscopy and imaging in THz frequency range

    NASA Astrophysics Data System (ADS)

    Vaks, Vladimir L.

    2014-03-01

    Application of microwave methods for development of the THz frequency range has resulted in elaboration of high precision THz spectrometers based on nonstationary effects. The spectrometers characteristics (spectral resolution and sensitivity) meet the requirements for high precision analysis. The gas analyzers, based on the high precision spectrometers, have been successfully applied for analytical investigations of gas impurities in high pure substances. These investigations can be carried out both in absorption cell and in reactor. The devices can be used for ecological monitoring, detecting the components of chemical weapons and explosive in the atmosphere. The great field of THz investigations is the medicine application. Using the THz spectrometers developed one can detect markers for some diseases in exhaled air.

  3. Pico-Kelvin thermometry and temperature stabilization using a resonant optical cavity.

    PubMed

    Tan, Si; Wang, Suwen; Saraf, Shailendhar; Lipa, John A

    2017-02-20

    Ultra-high sensitivity temperature sensing and stable thermal control are crucial for many science experiments testing fundamental theories to high precision. Here we report the first pico-kevin scale thermometer operating at room temperature with an exceptionally low theoretical noise figure of ~70pK/Hz at 1 Hz and a high dynamic range of ~500 K. We have experimentally demonstrated a temperature sensitivity of <3.8nK/Hz at 1 Hz near room temperature, which is an order of magnitude improvement over the state of the art. We have also demonstrated an ultra-high stability thermal control system using this thermometer, achieving 3.7 nK stability at 1 s and ∼ 120 pK at 104 s, which is 10-100 times more stable than the state of the art. With some upgrades to this proof-of-principle device, we can expect it to be used for very high resolution tests of special relativity and in critical point phenomena.

  4. Mini-cavity-dumped laser

    NASA Technical Reports Server (NTRS)

    Reed, E.

    1981-01-01

    Lasers for use in high precision satellite ranging systems consist typically of an oscillator followed by several amplifier stages. While the shortest optical pulses are achieved by using a mode locked oscillator, such an oscillator is incompatible with the compact design needed in future, highly mobile systems. The laser oscillator achieves pulse lengths approaching those obtainable by mode locking, but in a much more compact and stable design. The oscillator uses two LiNbO3 Pockels cells inside the resonator. One Q-switches the oscillator, and the other is used in a pulse slicing scheme to cavity dump a portion of the circulating optical energy. The length of the optical output pulse measured at 425 + or - 50 picoseconds.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Optical 'magnetic mirror' metasurfaces using interference between Fabry-Pérot cavity resonances in coaxial apertures.

    PubMed

    Rajasekharan, Ranjith; Roberts, Ann

    2015-05-28

    Here we propose and computationally demonstrate a quasi-planar metasurface consisting of arrays of pairs of concentric coaxial apertures in a metallic film. The structure relies on destructive interference between Fabry-Pérot modes excited in each aperture at resonance producing transmitted fields that interfere destructively leading to suppressed transmission. Conversely, we show that in the case of a perfect conductor, near-perfect, broadband reflection can be achieved with zero phase change in the electric field and a variation of 2π on passing through the coincident resonances. Extending the concept to shorter wavelengths, we show that mirrors exhibiting close to a 2π phase excursion, albeit with a reduction in the amplitude reflection coefficient at resonance and a lower Q, can be also achieved. Structures such as these can be used to enhance light-matter interactions at surfaces and act as high impedance ground planes for antenna applications.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Whispering-gallery-mode-resonator-based ultranarrow linewidth external-cavity semiconductor laser.

    PubMed

    Liang, W; Ilchenko, V S; Savchenkov, A A; Matsko, A B; Seidel, D; Maleki, L

    2010-08-15

    We demonstrate a miniature self-injection locked distributed-feedback laser using resonant optical feedback from a high-Q crystalline whispering-gallery-mode resonator. The linewidth reduction factor is greater than 10,000, with resultant instantaneous linewidth of less than 200 Hz. The minimal value of the Allan deviation for the laser-frequency stability is 3 x 10(-12) at the integration time of 20 micros. The laser possesses excellent spectral purity and good long-term stability.

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

    PubMed

    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.

  10. Temperature dependence of the hydrated electron's excited-state relaxation. I. Simulation predictions of resonance Raman and pump-probe transient absorption spectra of cavity and non-cavity models

    NASA Astrophysics Data System (ADS)

    Zho, Chen-Chen; Farr, Erik P.; Glover, William J.; Schwartz, Benjamin J.

    2017-08-01

    We use one-electron non-adiabatic mixed quantum/classical simulations to explore the temperature dependence of both the ground-state structure and the excited-state relaxation dynamics of the hydrated electron. We compare the results for both the traditional cavity picture and a more recent non-cavity model of the hydrated electron and make definite predictions for distinguishing between the different possible structural models in future experiments. We find that the traditional cavity model shows no temperature-dependent change in structure at constant density, leading to a predicted resonance Raman spectrum that is essentially temperature-independent. In contrast, the non-cavity model predicts a blue-shift in the hydrated electron's resonance Raman O-H stretch with increasing temperature. The lack of a temperature-dependent ground-state structural change of the cavity model also leads to a prediction of little change with temperature of both the excited-state lifetime and hot ground-state cooling time of the hydrated electron following photoexcitation. This is in sharp contrast to the predictions of the non-cavity model, where both the excited-state lifetime and hot ground-state cooling time are expected to decrease significantly with increasing temperature. These simulation-based predictions should be directly testable by the results of future time-resolved photoelectron spectroscopy experiments. Finally, the temperature-dependent differences in predicted excited-state lifetime and hot ground-state cooling time of the two models also lead to different predicted pump-probe transient absorption spectroscopy of the hydrated electron as a function of temperature. We perform such experiments and describe them in Paper II [E. P. Farr et al., J. Chem. Phys. 147, 074504 (2017)], and find changes in the excited-state lifetime and hot ground-state cooling time with temperature that match well with the predictions of the non-cavity model. In particular, the experiments

  11. Resonance Raman and temperature-dependent electronic absorption spectra of cavity and noncavity models of the hydrated electron

    PubMed Central

    Casey, Jennifer R.; Larsen, Ross E.; Schwartz, Benjamin J.

    2013-01-01

    Most of what is known about the structure of the hydrated electron comes from mixed quantum/classical simulations, which depend on the pseudopotential that couples the quantum electron to the classical water molecules. These potentials usually are highly repulsive, producing cavity-bound hydrated electrons that break the local water H-bonding structure. However, we recently developed a more attractive potential, which produces a hydrated electron that encompasses a region of enhanced water density. Both our noncavity and the various cavity models predict similar experimental observables. In this paper, we work to distinguish between these models by studying both the temperature dependence of the optical absorption spectrum, which provides insight into the balance of the attractive and repulsive terms in the potential, and the resonance Raman spectrum, which provides a direct measure of the local H-bonding environment near the electron. We find that only our noncavity model can capture the experimental red shift of the hydrated electron’s absorption spectrum with increasing temperature at constant density. Cavity models of the hydrated electron predict a solvation structure similar to that of the larger aqueous halides, leading to a Raman O–H stretching band that is blue-shifted and narrower than that of bulk water. In contrast, experiments show the hydrated electron has a broader and red-shifted O–H stretching band compared with bulk water, a feature recovered by our noncavity model. We conclude that although our noncavity model does not provide perfect quantitative agreement with experiment, the hydrated electron must have a significant degree of noncavity character. PMID:23382233

  12. Resonance Raman and temperature-dependent electronic absorption spectra of cavity and noncavity models of the hydrated electron.

    PubMed

    Casey, Jennifer R; Larsen, Ross E; Schwartz, Benjamin J

    2013-02-19

    Most of what is known about the structure of the hydrated electron comes from mixed quantum/classical simulations, which depend on the pseudopotential that couples the quantum electron to the classical water molecules. These potentials usually are highly repulsive, producing cavity-bound hydrated electrons that break the local water H-bonding structure. However, we recently developed a more attractive potential, which produces a hydrated electron that encompasses a region of enhanced water density. Both our noncavity and the various cavity models predict similar experimental observables. In this paper, we work to distinguish between these models by studying both the temperature dependence of the optical absorption spectrum, which provides insight into the balance of the attractive and repulsive terms in the potential, and the resonance Raman spectrum, which provides a direct measure of the local H-bonding environment near the electron. We find that only our noncavity model can capture the experimental red shift of the hydrated electron's absorption spectrum with increasing temperature at constant density. Cavity models of the hydrated electron predict a solvation structure similar to that of the larger aqueous halides, leading to a Raman O-H stretching band that is blue-shifted and narrower than that of bulk water. In contrast, experiments show the hydrated electron has a broader and red-shifted O-H stretching band compared with bulk water, a feature recovered by our noncavity model. We conclude that although our noncavity model does not provide perfect quantitative agreement with experiment, the hydrated electron must have a significant degree of noncavity character.

  13. Ovenized microelectromechanical system (MEMS) resonator

    SciTech Connect

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

    2014-03-11

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

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

    PubMed

    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.

  15. Rydberg levels and ionization potential of francium measured by laser-resonance ionization in a hot cavity

    SciTech Connect

    Andreev, S.V.; Mishin, V.I.; Letokhov, V.S.

    1988-10-01

    A highly sensitive method of detecting atoms in samples has been used for spectral investigations of the rare radioactive element Fr. The method is based on laser-resonance photoionization of Fr atoms in a hot quasi-enclosed cavity. The investigations have been carried out with samples in which short-lived radioactive /sup 221/Fr atoms formed at a rate of approximately 10/sup 3/ atoms/sec. The data obtained, to our knowledge for the first time, on the energies of the high-lying Rydberg levels of the /sup 2/S/sub 1/2/ and /sup 2/D series have made it possible to determine the electron binding energy of the 7p /sup 2/P/sub 3/2/ state and to establish the ionization potential of Fr accurately.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-05-01

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

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Closed-loop control of flow-induced sound in a flow duct with downstream resonant cavities.

    PubMed

    Lu, Z B; Halim, D; Cheng, L

    2013-03-01

    A closed-loop-controlled surface perturbation technique was developed for controlling the flow-induced sound in a flow duct and acoustic resonance inside downstream cavities. The surface perturbation was created by piezo-ceramic THUNDER (THin layer composite UNimorph Driver and sEnsoR) actuators embedded underneath the surface of a test model with a semi-circular leading edge. A modified closed-loop control scheme based on the down-sampling theory was proposed and implemented due to the practical vibration characteristic limitation of THUNDER actuators. The optimally tuned control achieved a sound pressure reduction of 17.5 dB in the duct and 22.6 dB inside the cavity at the vortex shedding frequency, respectively. Changes brought up by the control in both flow and acoustic fields were analyzed in terms of the spectrum phase shift of the flow field over the upper surface of the test model, and a shift in the vortex shedding frequency. The physical mechanism behind the control was investigated in the view of developing an optimal control strategy.

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

    SciTech Connect

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

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  4. VIEW OF MICROMACHINING, HIGH PRECISION EQUIPMENT USED TO CUSTOM MAKE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF MICRO-MACHINING, HIGH PRECISION EQUIPMENT USED TO CUSTOM MAKE SMALL PARTS. LUMPS OF CLAY; SHOWN IN THE PHOTOGRAPH, WERE USED TO STABILIZE PARTS BEING MACHINED. (11/1/87) - Rocky Flats Plant, Stainless Steel & Non-Nuclear Components Manufacturing, Southeast corner of intersection of Cottonwood & Third Avenues, Golden, Jefferson County, CO

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

    PubMed

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

    2008-08-18

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

  6. Large Dispersive Shift of Cavity Resonance Induced by a Superconducting Flux Qubit in the Straddling Regime

    NASA Astrophysics Data System (ADS)

    Inomata, Kunihiro; Yamamoto, Tsuyoshi; Billangeon, Pierre-M.; Lin, Zhirong; Nakamura, Yasunobu; Tsai, Jaw-Shen; Koshino, Kazuki

    2013-03-01

    We demonstrate enhancement of the dispersive frequency shift in a coplanar waveguide resonator induced by a capacitively coupled superconducting flux qubit in the straddling regime. The magnitude of the observed shift, 80 MHz for the qubit-resonator detuning of 5 GHz, is quantitatively explained by the generalized Rabi model which takes into account the contribution of the qubit higher energy levels. By applying the enhanced dispersive shift to the qubit readout, we achieved 90 % contrast of the Rabi oscillations which is mainly limited by the energy relaxation of the qubit. We also discuss the qubit readout using a Josephson parametric amplifier. This work was supported by the MEXT Kakenhi ``Quantum Cybernetics'', the JSPS through its FIRST Program, and the NICT Commissioned Research.

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

    SciTech Connect

    Henares, J. L. Lecesne, N.; Hijazi, L.; Bastin, B.; Leroy, R.; Osmond, B.; Vignet, J. L.; Kron, T.; Naubereit, P.; Wendt, K.; Lassen, J.; Le Blanc, F.

    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. Spectral linewidth narrowing in a strongly coupled atom-cavity system via squeezed-light excitation of a ``vacuum'' Rabi resonance

    NASA Astrophysics Data System (ADS)

    Parkins, A. S.; Zoller, P.; Carmichael, H. J.

    1993-07-01

    The system consisting of a two-level atom coupled strongly to a cavity mode behaves as a two-state system when excited near one of the ``vacuum'' Rabi resonances. With finite-bandwidth squeezed light incident upon the cavity and tuned to one of these resonances, we show that it is possible to realize a two-state system coupled to a squeezed vacuum. This system exhibits subnatural linewidths in the emitted spectra, as described by Gardiner [Phys. Rev. Lett. 56, 1917 (1986)] in a study of spontaneous emission of a two-level atom in a squeezed vacuum, but requires that only a single cavity mode be subject to squeezing rather than the entire three-dimensional vacuum.

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

    NASA Astrophysics Data System (ADS)

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Effects of various cavity designs on the performance of a CO2 TEA laser with an unstable resonator

    NASA Technical Reports Server (NTRS)

    Zhao, Yanzeng; Post, Madison J.; Lawrence, T. R.

    1992-01-01

    Unstable resonator modeling has been carried out for an injection-seeded CO2 transversely excited atmosphere (TEA) laser in the NOAA/ERL/Wave Propagation Laboratory (WPL) Doppler lidar to examine the effects of various cavity designs on the quality of the output beam. The results show the effects of an injection pinhole, electrode spacing, mirror tilt, and radial reflectivity function of the output coupler. The electrode spacing in this laser has negligible effect. The injection pinhole, however, produces complicated structures in the output patterns. If the pinhole is removed, the output pattern is much smoother, and the frequency jitter is smaller. Misalignment sensitivity is very closely related to the radial reflectivity function. The superparabolic function provides the highest coupling efficiency, largest beam size, and good collimation, but produces a slightly higher misalignment sensitivity compared with a parabolic function. The Gaussian function provides the lowest misalignment sensitivity, but it produces the smallest beam size and the largest beam divergence. Also, the coupling coefficient is 50 percent lower than the optimum value. Methods for using a flat diffraction grating in unstable resonators are also investigated. The best way is to use a flat grating/positive lens combination to replace the back concave mirror.

  12. Fiber-coupled, Littrow-grating cavity displacement sensor.

    PubMed

    Allen, Graham; Sun, Ke-Xun; Byer, Robert

    2010-04-15

    We have demonstrated a compact, optical-fiber-fed, optical displacement sensor utilizing a Littrow-mounted diffraction grating to form a low-finesse Fabry-Perot cavity. Length changes of the cavity are read out via the Pound-Drever-Hall rf modulation technique at 925 MHz. The sensor has a nominal working distance of 2 cm and a total dynamic range of 160 nm. The displacement noise floor was less than 3x10(-10) m/sqrt[Hz] above 10(-2) Hz, limited by the frequency drift of the reference laser. A frequency-stabilized laser would reduce the noise floor to below 10(-12) m/sqrt[Hz]. The use of a 925 MHz modulation frequency demonstrates high-precision readout of a low-finesse compact resonant cavity.

  13. Standing-wave resonances in plasmonic nanoumbrella cavities for color generation and colorimetric refractive index sensor

    NASA Astrophysics Data System (ADS)

    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.

  14. Non-volatile resonance modes of a photonic cavity in diamond produced by fine-tuning

    NASA Astrophysics Data System (ADS)

    Lozovik, A.; Tordjman, M.; Meyler, B.; Bayn, I.; Salzman, J.; Kalish, R.

    2016-10-01

    Methods of fine-tuning the properties of 1D triangular nanobeam diamond based photonic devices, with the aim of enhancing the photon collection efficiency at predetermined wavelengths at ambient temperature, are described. Delicate control of the physical dimensions of the device, which is required to obtain these advantages, is achieved by the deposition of HfO2 monolayers (thickening) and by H2 plasma etching (thinning). These shift the optical properties of the thus-treated photonic crystal to the red and to the blue, respectively. The methods described here demonstrate a practical and straight-forward way to fine-tune the diamond photonic nanocavity into resonance with the zero-phonon line of the Nitrogen-Vacancy (NV-) centers at room temperature with the availability to be kept storable. This approach paves the way to obtain a non-volatile nanobeam structure available at a desired predetermined resonance mode for a subsequent usage of the NV- emission in ambient conditions. It may find valuable applications in diamond-based quantum computing and communications.

  15. Non-linear resonance of fluids in a crystal growth cavity

    NASA Technical Reports Server (NTRS)

    Wang, Francis C.

    1996-01-01

    In the microgravity environment, the effect of gravity on fluid motion is much reduced. Hence, secondary effects such as vibrations, jitters, surface tension, capillary effects, and electromagnetic forces become the dominant mechanism of fluid convection. Numerous studies have been conducted to investigate fluid behavior in microgravity with the ultimate goal of developing processes with minimal influence from convection. Industrial applications such as crystal growth from solidification of melt and protein growth for pharmatheutical application are just a few examples of the vast potential benefit that can be reaped from material processing in space. However, a space laboratory is not immune from all undesirable disturbances and it is imperative that such disturbances be well understood, quantifiable, and controlled. Non-uniform and transient accelerations such as vibrations, jitters, and impulsive accelerations exist as a result of crew activities, space vehicle maneuvering, and the operations of on-board equipment. Measurements conducted on-board a U.S. Spacelab showed the existence of vibrations in the frequency range of 1 to 100 Hz with a dominant mode of 17 Hz and harmonics of 54 Hz. The observed vibration is not limited to any coordinate plane but exists in all directions. Similar situation exists on-board the Russian MIR space station. Due to the large structure of its design, the future International Space Station will have its own characteristic vibration spectrum. It is well known that vibration can exert substantial influence on heat and mass transfer processes, thus hindering any attempts to achieve a diffusion-limited process. Experiments on vibration convection for a liquid-filled enclosure under one-g environment showed the existence of different flow regimes as vibration frequency and intensity changes. Results showed the existence of a resonant frequency, near which the enhancement is the strongest, and the existence of a high frequency asymptote

  16. Design and control of a high precision drive mechanism

    NASA Astrophysics Data System (ADS)

    Pan, Bo; He, Yongqiang; Wang, Haowei; Zhang, Shuyang; Zhang, Donghua; Wei, Xiaorong; Jiang, Zhihong

    2017-01-01

    This paper summarizes the development of a high precision drive mechanism (HPDM) for space application, such as the directional antenna, the laser communication device, the mobile camera and other pointing mechanisms. In view of the great practical significance of high precision drive system, control technology for permanent magnet synchronous motor (PMSM) servo system is also studied and a PMSM servo controller is designed in this paper. And the software alignment was applied to the controller to eliminate the steady error of the optical encoder, which helps to realize the 1 arcsec (1σ) control precision. To assess its capabilities, the qualification environment testing including the thermal vacuum cycling testing, and the sinusoidal and random vibration were carried out. The testing results show that the performance of the HPDM is almost the same between the former and the end of each testing.

  17. Design of high-precision ranging system for laser fuze

    NASA Astrophysics Data System (ADS)

    Chen, Shanshan; Zhang, He; Xu, Xiaobin

    2016-10-01

    According to the problem of the high-precision ranging in the circumferential scanning probe laser proximity fuze, a new type of pulsed laser ranging system has been designed. The laser transmitting module, laser receiving module and ranging processing module have been designed respectively. The factors affecting the ranging accuracy are discussed. And the method of improving the ranging accuracy is studied. The high-precision ranging system adopts the general high performance microprocessor C8051FXXX as the core. And the time interval measurement chip TDC-GP21 was used to implement the system. A PCB circuit board was processed to carry on the experiment. The results of the experiment prove that a centimeter level accuracy ranging system has been achieved. The works can offer reference for ranging system design of the circumferential scanning probe laser proximity fuze.

  18. High-precision spectroscopy of hydrogen molecular ions

    NASA Astrophysics Data System (ADS)

    Zhong, Zhen-Xiang; Tong, Xin; Yan, Zong-Chao; Shi, Ting-Yun

    2015-05-01

    In this paper, we overview recent advances in high-precision structure calculations of the hydrogen molecular ions ( and HD+), including nonrelativistic energy eigenvalues and relativistic and quantum electrodynamic corrections. In combination with high-precision measurements, it is feasible to precisely determine a molecular-based value of the proton-to-electron mass ratio. An experimental scheme is presented for measuring the rovibrational transition frequency (v,L) : (0,0) → (6,1) in HD+, which is currently underway at the Wuhan Institute of Physics and Mathematics. Project supported by the National Natural Science Foundation of China (Grants Nos. 11474316, 11004221, 10974224, and 11274348), the “Hundred Talent Program” of Chinese Academy of Sciences. Yan Zong-Chao was supported by NSERC, SHARCnet, ACEnet of Canada, and the CAS/SAFEA International Partnership Program for Creative Research Teams.

  19. High-precision Photogrammetric Surface Figure Measurements under Cryogenic Environment

    NASA Astrophysics Data System (ADS)

    Lou, Z.; Qian, Y.; Fan, S. H.; Liu, C. R.; Wang, H. R.; Zuo, Y. X.; Cheng, J. Q.; Yang, J.

    2016-01-01

    Limited by the working temperature of the measurement equipments, most of the high-precision surface figure measurement techniques cannot be applied under a cryogenic environment. This paper reports the first attempt to measure the surface figure of a high-precision terahertz reflector panel under low temperatures based on photogrammetry. The measurement employs a high resolution industrial camera sitting on an automatic experimental platform which enables photos been taken in an automatic fashion inside a climate chamber. A repeatable accuracy of 2.1 μm rms is achieved under the cryogenic environment. Furthermore, surface figure measured by a three-coordinate measuring machine under room temperature is used to calibrate the thickness variation of the paper targets. By this technique, the surface figure of an aluminum prototype panel of the 5 meter Dome A Terahertz Telescope (DATE5) is measured from room temperature down to -55°C.

  20. High Precision Measurement of the ^19Ne Lifetime

    NASA Astrophysics Data System (ADS)

    Broussard, Leah; Back, H. O.; Boswell, M. S.; Crowell, A. S.; Howell, C. R.; Kidd, M. F.; Pattie, R. W., Jr.; Young, A. R.; Dendooven, P. G.; Giri, G. S.; van der Hoek, D. J.; Jungmann, K.; Kruithof, W. L.; Onderwater, C. J. G.; Santra, B.; Shidling, P. D.; Sohani, M.; Versolota, O. O.; Willmann, L.; Wilschut, H. W.

    2009-10-01

    Recently, a rigorous review of the T=12 mirror transitions has identified several systems which can contribute to high precision tests exploring deviations from the Standard Model's description of the electroweak interaction. Arguably, one of the best candidates is the &+circ; decay of ^19Ne to ^19F. In this system, the main contribution to the uncertainty of extracted Standard Model parameters is due to the measured value of the lifetime of the decay. In March 2009, a high precision measurement of the lifetime of ^19Ne was made by a collaboration between the Triangle Universities Nuclear Laboratory (TUNL) and the Kernfysisch Versneller Instituut (KVI) at the Trapped Radioactive Isotopes: Microlaboratories for Fundamental Physics (Triμp) facility. An overview of the experiment and preliminary results will be presented.

  1. Computer-Aided High Precision Verification Of Miniature Spring Structure

    NASA Astrophysics Data System (ADS)

    Bow, Sing T.; Wang, Da-hao; Chen, Tsung-sheng; Newell, Darrell E.

    1990-01-01

    A system is proposed for the high precision on-line verification of the minia-ture spring structure, including overall height, diameters of various coils as well as pitches between neighboring coils of the miniature conical springs. High preci-sion measurements without physical contact and short processing time are achieved. Deformations of any kind on the conical springs can be identified even from the worst viewing direction.

  2. System and method for high precision isotope ratio destructive analysis

    DOEpatents

    Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

    2013-07-02

    A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

  3. Dipole model analysis of high precision HERA data

    NASA Astrophysics Data System (ADS)

    Luszczak, A.; Kowalski, H.

    2014-04-01

    We analyze, within a dipole model, the inclusive deep inelastic scattering cross section data, obtained from the combination of the measurements of the H1 and ZEUS experiments performed at the HERA collider. We show that these high precision data are very well described within the dipole model framework, which is complemented with valence quark structure functions. We discuss the properties of the gluon density obtained in this way.

  4. High-Precision Direct Method for the Radiative Transfer Problems

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Hou, Su-Qing; Yang, Ping; Wu, Kai-Su

    2013-06-01

    It is the main aim of this paper to investigate the numerical methods of the radiative transfer equation. Using the five-point formula to approximate the differential part and the Simpson formula to substitute for integral part respectively, a new high-precision numerical scheme, which has 4-order local truncation error, is obtained. Subsequently, a numerical example for radiative transfer equation is carried out, and the calculation results show that the new numerical scheme is more accurate.

  5. High precision radial velocities: the case for NIR.

    NASA Astrophysics Data System (ADS)

    Carleo, I.; Gratton, R.

    In the context of the preparation for the high resolution spectrograph HIRES for E-ELT, we are studying the possibility to derive high-precision radial velocities (RV) on a prototype:GIANO, the near-infrared (NIR) echelle spectrograph now available at the Telescopio Nazionale Galileo. Radial velocities measured from near-infrared spectra are a potential tool to search for extrasolar planets around cool stars. High resolution infrared spectrographs now available are reaching the high precision of visible instruments, with a constant improvement over time. In particular, no other IR instruments have GIANO's capability to cover the entire NIR wavelength range. We have developed an ensemble of IDL procedures to measure high precision radial velocities on GIANO spectra. Taking into account the achieved precisions with GIANO, we constrain the sample of targets for which GIANO is better than HARPS-N, but with the advent of GIARPS (GIANO+HARPS-N), GIANO will improve its performances and include a much larger sample of stars. The NIR range is the future of RV measurements, especially because the jitter due to the star surface activities is reduced in the NIR. As a consequence, HIRES working in NIR range might be very useful, and for a wide range of cases, it will be more efficient than HIRES working in the visible range, for detection and characterization of planets using radial velocity technique.

  6. Compound cavity theory of resonant phase modulation in laser self-mixing ultrasonic vibration measurement

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Ciovati, Gianluigi; Dhakal, Pashupati; Gurevich, Alexander V.

    2014-03-03

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

  8. Note: Studies on target placement in TE(111) cylindrical cavity of electron cyclotron resonance x-ray source for the enhancement of x-ray dose.

    PubMed

    Selvakumaran, T S; Baskaran, R; Singh, A K; Sista, V L S Rao

    2010-03-01

    X-ray source based on electron cyclotron resonance principle has been constructed using TE(111) cylindrical cavity. At present the device is used to provide low energy x-ray field for thermoluminescent dosimeter badge calibration. Theoretical and experimental studies on the effect of target placement inside the TE(111) cylindrical cavity for enhancing the x-ray output are carried out and the results are presented in this note. Optimum target location is identified by theoretical analysis on the electric field distribution inside the cavity using MICROWAVE STUDIO program. By modifying the magnetic field configuration, the resonance region is shifted to the optimum target location. The microwave transmission line is upgraded with a three stub tuner which improves the microwave coupling from the source to the target loaded cavity. Molybdenum target is located at a radial distance of 2.5 cm from the cavity center and the x-ray dose rate is measured at 20 cm from the exit port for different microwave power. With the introduction of the target, the x-ray output has improved nearly from 70% to 160% in the microwave power of 150-500 W.

  9. Note: Studies on target placement in TE{sub 111} cylindrical cavity of electron cyclotron resonance x-ray source for the enhancement of x-ray dose

    SciTech Connect

    Selvakumaran, T. S.; Baskaran, R.; Singh, A. K.; Sista, V. L. S. Rao

    2010-03-15

    X-ray source based on electron cyclotron resonance principle has been constructed using TE{sub 111} cylindrical cavity. At present the device is used to provide low energy x-ray field for thermoluminescent dosimeter badge calibration. Theoretical and experimental studies on the effect of target placement inside the TE{sub 111} cylindrical cavity for enhancing the x-ray output are carried out and the results are presented in this note. Optimum target location is identified by theoretical analysis on the electric field distribution inside the cavity using MICROWAVE STUDIO program. By modifying the magnetic field configuration, the resonance region is shifted to the optimum target location. The microwave transmission line is upgraded with a three stub tuner which improves the microwave coupling from the source to the target loaded cavity. Molybdenum target is located at a radial distance of 2.5 cm from the cavity center and the x-ray dose rate is measured at 20 cm from the exit port for different microwave power. With the introduction of the target, the x-ray output has improved nearly from 70% to 160% in the microwave power of 150-500 W.

  10. Improved apparatus for trapped radical and other studies down to 1.5 K. [microwave cavity cryogenic equipment for electron paramagnetic resonance experiments

    NASA Technical Reports Server (NTRS)

    Woollam, J. A.; Sugawara, K.

    1978-01-01

    A Dewar system and associated equipment for electron paramagnetic resonance (EPR) studies of trapped free radicals and other optical or irradiation experiments are described. The apparatus is capable of reaching a temperature of 1.5 K and transporting on the order of 20 W per K temperature gradient; its principal advantages are for use at pumped cryogen temperatures and for experiments with large heat inputs. Two versions of the apparatus are discussed, one of which is designed for EPR in a rectangular cavity operating in a TE(102) mode and another in which EPR is performed in a cylindrical microwave cavity.

  11. Cavity magnomechanics

    PubMed Central

    Zhang, Xufeng; Zou, Chang-Ling; Jiang, Liang; Tang, Hong X.

    2016-01-01

    A dielectric body couples with electromagnetic fields through radiation pressure and electrostrictive forces, which mediate phonon-photon coupling in cavity optomechanics. In a magnetic medium, according to the Korteweg-Helmholtz formula, which describes the electromagnetic force density acting on a medium, magneostrictive forces should arise and lead to phonon-magnon interaction. We report such a coupled phonon-magnon system based on ferrimagnetic spheres, which we term as cavity magnomechanics, by analogy to cavity optomechanics. Coherent phonon-magnon interactions, including electromagnetically induced transparency and absorption, are demonstrated. Because of the strong hybridization of magnon and microwave photon modes and their high tunability, our platform exhibits new features including parametric amplification of magnons and phonons, triple-resonant photon-magnon-phonon coupling, and phonon lasing. Our work demonstrates the fundamental principle of cavity magnomechanics and its application as a new information transduction platform based on coherent coupling between photons, phonons, and magnons. PMID:27034983

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  13. Precise Frequency Measurements Using a Superconducting Cavity Stabilized Oscillator

    NASA Technical Reports Server (NTRS)

    Strayer, D. M.; Yeh, N.-C.; Jiang, W.; Anderson, V. L.; Asplund, N.

    1999-01-01

    Many physics experiments call on improved resolution to better define the experimental results, thus improving tests of theories. Modern microwave technology combined with high-Q resonators can achieve frequency readout and control with resolutions up to a part in 10(exp 18). When the physical quantity in question in the experiment can be converted to a frequency or a change in frequency, a high-stability microwave oscillator can be applied to obtain state-of-the-art precision. In this work we describe the overall physical concepts and the required experimental procedures for optimizing a high-resolution frequency measurement system that employs a high-Q superconducting microwave cavity and a low-noise frequency synthesizer. The basic approach is to resolve the resonant frequencies of a high-Q (Q > 10(exp 10)) cavity to extremely high precision (one part in 10(exp 17)- 10(exp 18)). Techniques for locking the synthesizer frequency to a resonant frequency of the superconducting cavity to form an ultra-stable oscillator are described. We have recently set up an ultra-high-vacuum high-temperature annealing system to process superconducting niobium cavities, and have been able to consistently achieve Q > 10(exp 9). We have integrated high-Q superconducting cavities with a low-noise microwave synthesizer in a phase-locked-loop to verify the frequency stability of the system. Effects that disturb the cavity resonant frequency (such as the temperature fluctuations and mechanical vibrations) and methods to mitigate those effects are also considered. Applicability of these techniques to experiments will be discussed, and our latest experimental progress in achieving high-resolution frequency measurements using the superconducting-cavity-stabilized-oscillator will be presented.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Progress Towards a High-Precision Infrared Spectroscopic Survey of the H_3^+ Ion

    NASA Astrophysics Data System (ADS)

    Perry, Adam J.; Hodges, James N.; Markus, Charles R.; Kocheril, G. Stephen; Jenkins, Paul A., II; McCall, Benjamin J.

    2015-06-01

    The trihydrogen cation, H_3^+, represents one of the most important and fundamental molecular systems. Having only two electrons and three nuclei, H_3^+ is the simplest polyatomic system and is a key testing ground for the development of new techniques for calculating potential energy surfaces and predicting molecular spectra. Corrections that go beyond the Born-Oppenheimer approximation, including adiabatic, non-adiabatic, relativistic, and quantum electrodynamic corrections are becoming more feasible to calculate. As a result, experimental measurements performed on the H_3^+ ion serve as important benchmarks which are used to test the predictive power of new computational methods. By measuring many infrared transitions with precision at the sub-MHz level it is possible to construct a list of the most highly precise experimental rovibrational energy levels for this molecule. Until recently, only a select handful of infrared transitions of this molecule have been measured with high precision (˜ 1 MHz). Using the technique of Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy, we are aiming to produce the largest high-precision spectroscopic dataset for this molecule to date. Presented here are the current results from our survey along with a discussion of the combination differences analysis used to extract the experimentally determined rovibrational energy levels. O. Polyansky, et al., Phil. Trans. R. Soc. A (2012), 370, 5014. M. Pavanello, et al., J. Chem. Phys. (2012), 136, 184303. L. Diniz, et al., Phys. Rev. A (2013), 88, 032506. L. Lodi, et al., Phys. Rev. A (2014), 89, 032505. J. Hodges, et al., J. Chem. Phys (2013), 139, 164201.

  17. Narrow linewidth single-frequency terahertz source based on difference frequency generation of vertical-external-cavity source-emitting lasers in an external resonance cavity.

    PubMed

    Paul, Justin R; Scheller, Maik; Laurain, Alexandre; Young, Abram; Koch, Stephan W; Moloney, Jerome

    2013-09-15

    We demonstrate a continuous wave, single-frequency terahertz (THz) source emitting 1.9 THz. The linewidth is less than 100 kHz and the generated THz output power exceeds 100 μW. The THz source is based on parametric difference frequency generation within a nonlinear crystal located in an optical enhancement cavity. Two single-frequency vertical-external-cavity source-emitting lasers with emission wavelengths spaced by 6.8 nm are phase locked to the external cavity and provide pump photons for the nonlinear downconversion. It is demonstrated that the THz source can be used as a local oscillator to drive a receiver used in astronomy applications.

  18. Retrieving the spatial distribution of cavity modes in dielectric resonators by near-field imaging and electrodynamics simulations.

    PubMed

    Goñi, Alejandro R; Güell, Frank; Pérez, Luis A; López-Vidrier, Julian; Ossó, J Oriol; Coronado, Eduardo A; Morante, Joan R

    2012-03-07

    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.

  19. 20-Gbps WDM-PON transmissions employing weak-resonant-cavity FPLD with OFDM and SC-FDE modulation formats.

    PubMed

    Lu, I-Cheng; Wei, Chia-Chien; Jiang, Wen-Jr; Chen, Hsing-Yu; Chi, Yu-Chieh; Li, Yi-Cheng; Hsu, Dar-Zu; Lin, Gong-Ru; Chen, Jyehong

    2013-04-08

    Using a colorless weak-resonant-cavity (WRC) FPLD injected by a centralized light source, we have experimentally demonstrated a superior performance of 20-Gbps uplink transmission in a WDM-PON. Even though the typical modulation bandwidth of a WRC-FPLD is only ~1.25 GHz, using spectrally-efficient 32-QAM OFDM or SC-FDE modulation, 20-Gbps uplink signals can achieve the FEC limit after 25-km dispersion-uncompensated single-mode fiber transmission. Because of the advantage of lower PAPR, the SC-FDE signals outperform the OFDM signals with the fixed 32-QAM format in the proposed system; moreover, SC-FDE scheme can be another promising candidate for uplinks in WDM-PONs, for its simplification to ONUs. The signal at the mode of 1560.7 nm shows similar quality with the signal at the modes of 1545.3 nm and 1574.7 nm, the WRC-FPLD, accordingly, has wide injection wavelength range from at least 1545.3 nm to 1574.7 nm. With the mode spacing of 0.55 nm, consequently, we have demonstrated the applicability of the colorless WRC-FPLD on supporting up to 36 channels in the WDM-PON.

  20. Using active resonator impedance matching for shot-noise limited, cavity enhanced amplitude modulated laser absorption spectroscopy.

    PubMed

    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. Fabrication and metrology of high-precision freeform surfaces

    NASA Astrophysics Data System (ADS)

    Supranowitz, Chris; Dumas, Paul; Nitzsche, Tobias; DeGroote Nelson, Jessica; Light, Brandon B.; Medicus, Kate; Smith, Nathan

    2013-09-01

    Freeform applications are growing and include helmet-mounted displays, conformal optics (e.g. windows integrated into airplane wings), and those requiring the extreme precision of EUV. These non-rotationally symmetric surfaces pose challenges to optical fabrication, mostly in the areas of polishing and metrology. The varying curvature of freeform surfaces drives the need for smaller, more "conformal", tools for polishing and reference beams for interferometry. In this paper, we present fabrication results of a high-precision freeform surface. We will discuss the total manufacturing process, including generation, pre-polishing, MRF®, and metrology, highlighting the capabilities available in today's optical fabrication companies.

  2. High-precision measurements of global stellar magnetic fields

    NASA Astrophysics Data System (ADS)

    Plachinda, S. I.

    2014-06-01

    This paper presents a brief history of the development of devices and techniques for high-precision measurements of stellar magnetic fields. Two main approaches for the processing of spectral-polarimetric observations are described: the method of least-squares deconvolution (LSD), which is used to find a mean-weighted average of the normalized polarization profile using a set of spectral lines, and a method in which each individual spectral line is used to determine the magnetic field, viz., the single line method (SL). The advantages and disadvantages of the LSD and SL methods are discussed.

  3. High precision photon flux determination for photon tagging experiments

    SciTech Connect

    Teymurazyan, A.; Ahmidouch, A.; Ambrozewicz, P.; Asratyan, A.; Baker, K.; Benton, L.; Burkert, V.; Clinton, E.; Cole, P.; Collins, P.; Dale, D.; Danagoulian, S.; Davidenko, G.; Demirchyan, R.; Deur, A.; Dolgolenko, A.; Dzyubenko, G.; Ent, R.; Evdokimov, A.; Feng, J.; Gabrielyan, M.; Gan, L.; Gasparian, A.; Glamazdin, A.; Goryachev, V.; Hardy, K.; He, J.; Ito, M.; Jiang, L.; Kashy, D.; Khandaker, M.; Kolarkar, A.; Konchatnyi, M.; Korchin, A.; Korsch, W.; Kosinov, O.; Kowalski, S.; Kubantsev, M.; Kubarovsky, V.; Larin, I.; Lawrence, D.; Li, X.; Martel, P.; Matveev, V.; McNulty, D.; Mecking, B.; Milbrath, B.; Minehart, R.; Miskimen, R.; Mochalov, V.; Nakagawa, I.; Overby, S.; Pasyuk, E.; Payen, M.; Pedroni, R.; Prok, Y.; Ritchie, B.; Salgado, C.; Shahinyan, A.; Sitnikov, A.; Sober, D.; Stepanyan, S.; Stevens, W.; Underwood, J.; Vasiliev, A.; Vishnyakov, V.; Wood, M.; Zhou, S.

    2014-12-01

    The Jefferson Laboratory PrimEx Collaboration has developed and implemented a method to control the tagged photon flux in photoproduction experiments at the 1% level over the photon energy range from 4.9 to 5.5 GeV. This method has been successfully implemented in a high precision measurement of the neutral pion lifetime. Here, we outline the experimental equipment and the analysis techniques used to accomplish this. These include the use of a total absorption counter for absolute flux calibration, a pair spectrometer for online relative flux monitoring, and a new method for post-bremsstrahlung electron counting.

  4. GENERATION AND CONTROL OF HIGH PRECISION BEAMS AT LEPTON ACCELERATORS

    SciTech Connect

    Yu-Chiu Chao

    2007-06-25

    Parity violation experiments require precision manipulation of helicity-correlated beam coordinates on target at the nm/nrad-level. Achieving this unprecedented level of control requires a detailed understanding of the particle optics and careful tuning of the beam transport to keep anomalies from compromising the design adiabatic damping. Such efforts are often hindered by machine configuration and instrumentation limitations at the low energy end. A technique has been developed at CEBAF including high precision measurements, Mathematica-based analysis for obtaining corrective solutions, and control hardware/software developments for realizing such level of control at energies up to 5 GeV.

  5. Multidimensional Image Analysis for High Precision Radiation Therapy.

    PubMed

    Arimura, Hidetaka; Soufi, Mazen; Haekal, Mohammad

    2017-01-01

    High precision radiation therapy (HPRT) has been improved by utilizing conventional image engineering technologies. However, different frameworks are necessary for further improvement of HPRT. This review paper attempted to define the multidimensional image and what multidimensional image analysis is, which may be feasible for increasing the accuracy of HPRT. A number of researches in radiation therapy field have been introduced to understand the multidimensional image analysis. Multidimensional image analysis could greatly assist clinical staffs in radiation therapy planning, treatment, and prediction of treatment outcomes.

  6. High precision applications of the global positioning system

    NASA Technical Reports Server (NTRS)

    Lichten, Stephen M.

    1991-01-01

    The Global Positioning System (GPS) is a constellation of U.S. defense navigation satellites which can be used for military and civilian positioning applications. A wide variety of GPS scientific applications were identified and precise positioning capabilities with GPS were already demonstrated with data available from the present partial satellite constellation. Expected applications include: measurements of Earth crustal motion, particularly in seismically active regions; measurements of the Earth's rotation rate and pole orientation; high-precision Earth orbiter tracking; surveying; measurements of media propagation delays for calibration of deep space radiometric data in support of NASA planetary missions; determination of precise ground station coordinates; and precise time transfer worldwide.

  7. Strategies for high-precision Global Positioning System orbit determination

    NASA Technical Reports Server (NTRS)

    Lichten, Stephen M.; Border, James S.

    1987-01-01

    Various strategies for the high-precision orbit determination of the GPS satellites are explored using data from the 1985 GPS field test. Several refinements to the orbit determination strategies were found to be crucial for achieving high levels of repeatability and accuracy. These include the fine tuning of the GPS solar radiation coefficients and the ground station zenith tropospheric delays. Multiday arcs of 3-6 days provided better orbits and baselines than the 8-hr arcs from single-day passes. Highest-quality orbits and baselines were obtained with combined carrier phase and pseudorange solutions.

  8. Future high precision experiments and new physics beyond Standard Model

    SciTech Connect

    Luo, Mingxing

    1993-04-01

    High precision (< 1%) electroweak experiments that have been done or are likely to be done in this decade are examined on the basis of Standard Model (SM) predictions of fourteen weak neutral current observables and fifteen W and Z properties to the one-loop level, the implications of the corresponding experimental measurements to various types of possible new physics that enter at the tree or loop level were investigated. Certain experiments appear to have special promise as probes of the new physics considered here.

  9. Future high precision experiments and new physics beyond Standard Model

    SciTech Connect

    Luo, Mingxing.

    1993-01-01

    High precision (< 1%) electroweak experiments that have been done or are likely to be done in this decade are examined on the basis of Standard Model (SM) predictions of fourteen weak neutral current observables and fifteen W and Z properties to the one-loop level, the implications of the corresponding experimental measurements to various types of possible new physics that enter at the tree or loop level were investigated. Certain experiments appear to have special promise as probes of the new physics considered here.

  10. High-precision HST proper motions of globular clusters

    NASA Astrophysics Data System (ADS)

    Bellini, A.

    Photometric and spectroscopic studies over the last 15 years have revolutionized our understanding of globular clusters (GCs). We now know that essentially all GCs host multiple stellar populations that can be identified along all evolutionary sequences and are characterized by differences in light elements, He, and sometimes Fe. These findings present a number of formidable challenges for the study of the formation and evolution of GCs. The internal kinematics of multiple stellar populations is a fundamental piece of the puzzle and high-precision proper motions are the key tool to shed light on many open questions regarding GCs.

  11. High-precision micro/nano-scale machining system

    DOEpatents

    Kapoor, Shiv G.; Bourne, Keith Allen; DeVor, Richard E.

    2014-08-19

    A high precision micro/nanoscale machining system. A multi-axis movement machine provides relative movement along multiple axes between a workpiece and a tool holder. A cutting tool is disposed on a flexible cantilever held by the tool holder, the tool holder being movable to provide at least two of the axes to set the angle and distance of the cutting tool relative to the workpiece. A feedback control system uses measurement of deflection of the cantilever during cutting to maintain a desired cantilever deflection and hence a desired load on the cutting tool.

  12. Strong-coupling cavity QED using rare-earth-metal-ion dopants in monolithic resonators: What you can do with a weak oscillator

    SciTech Connect

    McAuslan, D. L.; Longdell, J. J.; Sellars, M. J.

    2009-12-15

    We investigate the possibility of achieving the strong coupling regime of cavity quantum electrodynamics using rare-earth-metal-ions as impurities in monolithic optical resonators. We conclude that due to the weak oscillator strengths of the rare-earth-metals, it may be possible but difficult to reach the regime where the single photon Rabi frequency is large compared to both the cavity and atom decay rates. However, reaching the regime where the saturation photon and atom numbers are less than one should be much more achievable. We show that in this 'bad cavity' regime, transfer of quantum states and an optical phase shift conditional on the state of the atom is still possible and suggest a method for coherent detection of single dopants.

  13. Cavity-enhanced AlGaAs/GaAs resonant tunneling photodetectors for telecommunication wavelength light detection at 1.3 μm

    NASA Astrophysics Data System (ADS)

    Pfenning, Andreas; Hartmann, Fabian; Langer, Fabian; Kamp, Martin; Höfling, Sven; Worschech, Lukas

    2015-09-01

    We demonstrate a cavity-enhanced photodetector at the telecommunication wavelength of λ = 1.3 μm based on a resonant tunneling diode (RTD). The cavity-enhanced RTD photodetector consists of three integral parts: First, a Ga0.89In0.11N0.04As0.96 absorption layer that can be grown lattice-matched on GaAs and which is light-active in the near infrared spectral region due to its reduced bandgap energy. Second, an Al0.6Ga0.4As/GaAs double barrier resonant tunneling structure (RTS) that serves as high gain internal amplifier of weak electric signals caused by photogenerated electron-hole pairs within the GaInNAs absorption layer. Third, an optical distributed Bragg reflector (DBR) cavity consisting of five top and seven bottom alternating GaAs/AlAs mirror pairs, which provides an enhanced quantum efficiency at the resonance wavelength. The samples were grown by molecular beam epitaxy. Electro-optical properties of the RTDs were studied at room temperature. From the reflection-spectrum the optical resonance at λ = 1.29 μm was extracted. The current-voltage characteristics were studied in the dark and under illumination and a wellpronounced photo-response was found and is attributed to accumulation of photogenerated holes in the vicinity of the RTS. The maximum photocurrent was found at the optical resonance of 1.29 μm. At resonance, a sensitivity of S = 3.97 × 104 A/W was observed. From the sensitivity, a noise equivalent power of NEP = 1.18 × 10-16 W/Hz1/2, and a specific detectivity of D∗ ≅ 6.74 × 1012 cm Hz1/2/W were calculated. For a single absorbed photon a photocurrent of ISP = 50 pA was determined.

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

    PubMed

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

    2014-12-01

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

  15. Design and test of a resonance control system for suppressing the pump vibration effects for the PEFP 13-MHz RF cavity

    NASA Astrophysics Data System (ADS)

    Li, Ying-Min; Cha, Sung-Su; Jang, Ji-Ho; Kwon, Hyeok-Jung; Song, Young-Gi; Kim, Han-Sung; Seol, Kyung-Tae; Cho, Yong-Sub; Trinh, Tu-Anh

    2013-11-01

    The Proton Engineering Frontier Project developed a 13-MHz pulsed, RF cavity for heavy-ion implanter applications. Typically, slow changes in the room temperature and the mechanical vibrations of the vacuum device may be primary sources of disturbances, and the accelerating cavity of the implanter may not be able to operate at the resonance frequency owing to disturbance effects. We need a voltage-controlled oscillator phased-locked loop circuit to make a control system that could suppress the disturbance effects; thus, the accelerating gradient of the cavity always reached a peak level for a given input power and coupling. An analog-circuit-based RF-frequency-tracking system was developed. Next, we obtained the optimal control parameters for the key control components. Finally, we measured the system performance between an open loop and a closed loop. The key point of the system design is to control the driving frequency that is used to operate the RF source by keeping the phase at around 0 degrees with respect to the resonance peak of the cavity. The experimental results showed that the fluctuations of the control loop error signal were suppressed by about a factor of 10. The presented feedback loop is implemented as a standard proportional controller. The loop p-gain is 120 k.

  16. High precision capacitive beam phase probe for KHIMA project

    NASA Astrophysics Data System (ADS)

    Hwang, Ji-Gwang; Yang, Tae-Keun; Forck, Peter

    2016-11-01

    In the medium energy beam transport (MEBT) line of KHIMA project, a high precision beam phase probe monitor is required for a precise tuning of RF phase and amplitude of Radio Frequency Quadrupole (RFQ) accelerator and IH-DTL linac. It is also used for measuring a kinetic energy of ion beam by time-of-flight (TOF) method using two phase probes. The capacitive beam phase probe has been developed. The electromagnetic design of the high precision phase probe was performed to satisfy the phase resolution of 1° (@200 MHz). It was confirmed by the test result using a wire test bench. The measured phase accuracy of the fabricated phase probe is 1.19 ps. The pre-amplifier electronics with the 0.125 ∼ 1.61 GHz broad-band was designed and fabricated for amplifying the signal strength. The results of RF frequency and beam energy measurement using a proton beam from the cyclotron in KIRAMS is presented.

  17. Automated high precision secondary pH measurements

    NASA Astrophysics Data System (ADS)

    Bastkowski, F.; Jakobsen, P. T.; Stefan, F.; Kristensen, H. B.; Jensen, H. D.; Kawiecki, R.; Wied, C. E.; Kauert, A.; Seidl, B.; Spitzer, P.; Eberhardt, R.; Adel, B.

    2013-04-01

    A new setup for high precision, automated secondary pH measurements together with a reference measurement procedure has been developed and tested in interlaboratory comparisons using buffers pH 4.005, pH 7.000, and pH 10.012 at 25 °C and 37 °C. Using primary buffers as standards, a standard uncertainty in pH better than 0.005 can be reached. The central measuring device is a one piece, thermostatted cell of PFA (perfluoroalkoxy) with a built-in Hamilton® Single Pore™ Glass electrode. Due to its flow-through principle this device allows pH measurements with low consumption of measurement solutions. The very hydrophobic and smooth PFA as construction material facilitates complete emptying of the cell. Furthermore, the tempering unit affords very precise temperature control and hence contributes to the low target uncertainty of the produced secondary buffer solutions. Use of a symmetric measurement sequence and the two point calibration was sufficient to reach high precision and accuracy.

  18. Thermal design and flight validation for high precision camera

    NASA Astrophysics Data System (ADS)

    Meng, Henghui; Sun, Lixia; Zhang, Chuanqiang; Geng, Liyin

    2015-10-01

    High precision camera, designed for advanced optical system, with a wide field of vision, high resolution and fast response, has a wild range of applications. As the main payload for spacecraft, the optical remote sensor is mounted exposed to the space, which means it should have a reliable optical performance in harsh space environment during lifetime. Because of the special optical characteristic, imaging path should be accurate, and less thermal deformation for the optical parts is required in the working process, so the high precision camera has a high level requirement for temperature. High resolution space camera is generally required to own the capability of adapting to space thermal environments. The flexible satellite's change of rolling attitude affects the temperature distribution of the camera and makes a difference to optical performance. The thermal control design of space camera is presented, and analysis the temperature data in orbit to prove the thermal design correct. It is proved that the rolling attitude has more influence on outer parts and less influence on inner parts, and active thermal control can weaken the influence of rolling attitude.

  19. High-Precision Computation: Mathematical Physics and Dynamics

    SciTech Connect

    Bailey, D. H.; Barrio, R.; Borwein, J. M.

    2010-04-01

    At the present time, IEEE 64-bit oating-point arithmetic is suficiently accurate for most scientic applications. However, for a rapidly growing body of important scientic computing applications, a higher level of numeric precision is required. Such calculations are facilitated by high-precision software packages that include high-level language translation modules to minimize the conversion e ort. This pa- per presents a survey of recent applications of these techniques and provides someanalysis of their numerical requirements. These applications include supernova simulations, climate modeling, planetary orbit calculations, Coulomb n-body atomic systems, studies of the one structure constant, scattering amplitudes of quarks, glu- ons and bosons, nonlinear oscillator theory, experimental mathematics, evaluation of orthogonal polynomials, numerical integration of ODEs, computation of periodic orbits, studies of the splitting of separatrices, detection of strange nonchaotic at- tractors, Ising theory, quantum held theory, and discrete dynamical systems. We conclude that high-precision arithmetic facilities are now an indispensable compo- nent of a modern large-scale scientic computing environment.

  20. High precision wavelength meter with Fabry-Perot optics

    NASA Astrophysics Data System (ADS)

    Konishi, N.; Suzuki, T.; Taira, Y.; Kato, H.; Kasuya, T.

    1981-07-01

    A high precision wavelength meter in the visible is described, which is based on a Fabry-Perot interferometer with several etalons of different resolution. The interference fringe pattern projected on a photo-diode array detector is computationally processed to give a stepwise refinement of the wavelength value to any adjusted accuracy. The present model intends to provide digital and real-time values of high precision wavelength for dye-laser spectroscopy, and to serve as a monitor or as a pilot for wavelength control of a dye-laser source of nanosecond pulses. The model is, therefore, designed with particular emphasis on its short-pulse capability and on-line mode of operation as well as on its high sensitivity and resolution. Some arrangements of essential necessity are involved therein, such as to avoid an errorneous wavelength readout for a noisy incidence of pulsed field. The ultimate accuracy of wavelength measurement is prescribed by the resolving power of the thickest etalon employed. As applied to the pulsed source, the model determines the wavelength to the accuracy of ±one part in 107 for even a single shot nanosecond incidence of a fraction of μJ energy. The design and performance are described in connection to pulsed dye-laser incidence.

  1. PHASES High-Precision Differential Astrometry of δ Equulei

    NASA Astrophysics Data System (ADS)

    Muterspaugh, Matthew W.; Lane, Benjamin F.; Konacki, Maciej; Burke, Bernard F.; Colavita, M. M.; Kulkarni, S. R.; Shao, M.

    2005-12-01

    Delta Equulei is among the most well-studied nearby binary star systems. Results of its observation have been applied to a wide range of fundamental studies of binary systems and stellar astrophysics. It is widely used to calibrate and constrain theoretical models of the physics of stars. We report 27 high-precision differential astrometry measurements of δ Equ from the Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES). The median size of the minor axes of the uncertainty ellipses for these measurements is 26 μas. These data are combined with previously published radial velocity data and other previously published differential astrometry measurements using other techniques to produce a combined model for the system orbit. The distance to the system is determined to within one twentieth of a parsec, and the component masses are determined at the level of a percent. The constraints on masses and distance are limited by the precisions of the radial velocity data; we outline plans to improve this deficiency and discuss the outlook for further study of this binary.

  2. A High Precision Terahertz Wave Image Reconstruction Algorithm

    PubMed Central

    Guo, Qijia; Chang, Tianying; Geng, Guoshuai; Jia, Chengyan; Cui, Hong-Liang

    2016-01-01

    With the development of terahertz (THz) technology, the applications of this spectrum have become increasingly wide-ranging, in areas such as non-destructive testing, security applications and medical scanning, in which one of the most important methods is imaging. Unlike remote sensing applications, THz imaging features sources of array elements that are almost always supposed to be spherical wave radiators, including single antennae. As such, well-developed methodologies such as Range-Doppler Algorithm (RDA) are not directly applicable in such near-range situations. The Back Projection Algorithm (BPA) can provide products of high precision at the the cost of a high computational burden, while the Range Migration Algorithm (RMA) sacrifices the quality of images for efficiency. The Phase-shift Migration Algorithm (PMA) is a good alternative, the features of which combine both of the classical algorithms mentioned above. In this research, it is used for mechanical scanning, and is extended to array imaging for the first time. In addition, the performances of PMA are studied in detail in contrast to BPA and RMA. It is demonstrated in our simulations and experiments described herein that the algorithm can reconstruct images with high precision. PMID:27455269

  3. High Precision Photometry for the K2 Mission

    NASA Astrophysics Data System (ADS)

    Huang, Xu; Soares-Furtado, Melinda; Penev, Kaloyan; Hartman, Joel; Bakos, Gaspar; Bhatti, Waqas; Domsa, Istvan; de Val-Borro, Miguel

    2015-12-01

    The two reaction wheel K2 mission brings new challenges for the data reduction processes. We developed a reduction pipeline for extracting high precision photometry from the K2 dataset and we use this pipeline to generate light curves for the K2 Campaign 0 super-stamps and K2 Campaign 1 target pixel dataset. Key to our reduction technique is the derivation of global astrometric solutions from the target stamps from which accurate centroids are passed on for high precision photometry extraction. We also implemented the image subtraction method to reduce the K2 Campaign 0 super-stamps containing open clusters M35 and NGC2158. We extract target light curvesfor sources from a combined UCAC4 and EPIC catalogue -- this includes not only primary targets of the K2 Mission, but also other stars that happen to fall on the pixel stamps. Our astrometric solutions achieve a median residual of ~0.127". For bright stars, our best 6.5 hour precision for raw light curves is ~20 parts per million (ppm). For our detrended light curves, the best 6.5 hour precision achieved is ~15 ppm. We show that our detrended light curves have fewer systematic effects (or trends, or red-noise) than light curves produced by other groups from the same observations. We highlight the measurements of rotation curves using the K2 light curves of stars within open cluster M35 and NGC2158.

  4. High-precision camera distortion measurements with a ``calibration harp''

    NASA Astrophysics Data System (ADS)

    Tang, Zhongwei; Grompone von Gioi, Rafael; Monasse, Pascal; Morel, Jean-Michel

    2012-10-01

    This paper addresses the high precision measurement of the distortion of a digital camera from photographs. Traditionally, this distortion is measured from photographs of a flat pattern which contains aligned elements. Nevertheless, it is nearly impossible to fabricate a very flat pattern and to validate its flatness. This fact limits the attainable measurable precisions. In contrast, it is much easier to obtain physically very precise straight lines by tightly stretching good quality strings on a frame. Taking literally "plumb-line methods", we built a "calibration harp" instead of the classic flat patterns to obtain a high precision measurement tool, demonstrably reaching 2/100 pixel precisions. The harp is complemented with the algorithms computing automatically from harp photographs two different and complementary lens distortion measurements. The precision of the method is evaluated on images corrected by state-of-the-art distortion correction algorithms, and by popular software. Three applications are shown: first an objective and reliable measurement of the result of any distortion correction. Second, the harp permits to control state-of-the art global camera calibration algorithms: It permits to select the right distortion model, thus avoiding internal compensation errors inherent to these methods. Third, the method replaces manual procedures in other distortion correction methods, makes them fully automatic, and increases their reliability and precision.

  5. High-precision Photogrammetric Surface Figure Measurements under Cryogenic Environment

    NASA Astrophysics Data System (ADS)

    Zheng, Lou; Yuan, Qian; Sheng-hong, Fan; Chang-ru, Liu; Hai-ren, Wang; Ying-xi, Zuo; Jin-quan, Cheng; Ji, Yang

    2017-01-01

    Limited by the working temperature of the test equipment, most of high-precision surface figure measurement techniques cannot be put into application under a cryogenic environment. This paper reports the first attempt to measure the surface figure of a high-precision terahertz reflector panel under low temperatures based on photogrammetry. The measurement employs a high-resolution industrial camera sitting on the automatic testing platform which enables photos been taken in an automatic fashion inside a climate chamber. A repeatable accuracy of 2.1 μm (rms) is achieved under the cryogenic environment. Furthermore, the surface figure measured by a three-coordinate measuring machine under the room temperature is used to calibrate the thickness differences of the targets. By this technique, the surface figure of an aluminum prototype panel of the 5 meter Dome A Terahertz Telescope (DATE5) is measured from room temperature down to -55°C to obtain the rule of variation of surface deformation of the panel under low temperatures.

  6. High-precision ground-based photometry of exoplanets

    NASA Astrophysics Data System (ADS)

    de Mooij, Ernst J. W.; Jayawardhana, Ray

    2013-04-01

    High-precision photometry of transiting exoplanet systems has contributed significantly to our understanding of the properties of their atmospheres. The best targets are the bright exoplanet systems, for which the high number of photons allow very high signal-to-noise ratios. Most of the current instruments are not optimised for these high-precision measurements, either they have a large read-out overhead to reduce the readnoise and/or their field-of-view is limited, preventing simultaneous observations of both the target and a reference star. Recently we have proposed a new wide-field imager for the Observatoir de Mont-Megantic optimised for these bright systems (PI: Jayawardhana). The instruments has a dual beam design and a field-of-view of 17' by 17'. The cameras have a read-out time of 2 seconds, significantly reducing read-out overheads. Over the past years we have obtained significant experience with how to reach the high precision required for the characterisation of exoplanet atmospheres. Based on our experience we provide the following advice: Get the best calibrations possible. In the case of bad weather, characterise the instrument (e.g. non-linearity, dome flats, bias level), this is vital for better understanding of the science data. Observe the target for as long as possible, the out-of-transit baseline is as important as the transit/eclipse itself. A short baseline can lead to improperly corrected systematic and mis-estimation of the red-noise. Keep everything (e.g. position on detector, exposure time) as stable as possible. Take care that the defocus is not too strong. For a large defocus, the contribution of the total flux from the sky-background in the aperture could well exceed that of the target, resulting in very strict requirements on the precision at which the background is measured.

  7. The development of high precision carbon fiber composite mirror

    NASA Astrophysics Data System (ADS)

    Xu, Liang; Ding, Jiao-teng; Wang, Yong-jie; Xie, Yong-jie; Ma, Zhen; Fan, Xue-wu

    2016-10-01

    Due to low density, high stiffness, low thermal expansion coefficient, duplicate molding, etc., carbon fiber reinforced polymer (CFRP) is one of the potential materials of the optical mirror. The process developed for Φ300mm high precision CFRP mirror described in this paper. A placement tool used to improve laying accuracy up to ± 0.1°.A special reinforced cell structure designed to increase rigidity and thermal stability. Optical replication process adopted for surface modification of the carbon fiber composite mirror blank. Finally, surface accuracy RMS of Φ300mm CFRP mirror is 0.22μm, surface roughness Ra is about 2nm, and the thermal stability can achieve 13nm /°C from the test result. The research content is of some reference value in the infrared as well as visible light applications.

  8. Flight Test Performance of a High Precision Navigation Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Pierrottet, Diego; Amzajerdian, Farzin; Petway, Larry; Barnes, Bruce; Lockard, George

    2009-01-01

    A navigation Doppler Lidar (DL) was developed at NASA Langley Research Center (LaRC) for high precision velocity measurements from a lunar or planetary landing vehicle in support of the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. A unique feature of this DL is that it has the capability to provide a precision velocity vector which can be easily separated into horizontal and vertical velocity components and high accuracy line of sight (LOS) range measurements. This dual mode of operation can provide useful information, such as vehicle orientation relative to the direction of travel, and vehicle attitude relative to the sensor footprint on the ground. System performance was evaluated in a series of helicopter flight tests over the California desert. This paper provides a description of the DL system and presents results obtained from these flight tests.

  9. Monolithic interferometer for high precision radial velocity measurements

    NASA Astrophysics Data System (ADS)

    Wan, Xiaoke; Ge, Jian; Wang, Ji; Lee, Brian

    2009-08-01

    In high precision radial velocity (RV) measurements for extrasolar planets searching and studies, a stable wide field Michelson interferometer is very critical in Exoplanet Tracker (ET) instruments. Adopting a new design, monolithic interferometers are homogenous and continuous in thermal expansion, and field compensation and thermal compensation are both satisfied. Interferometer design and fabrication are decrypted in details. In performance evaluations, field angle is typically 22° and thermal sensitivity is typically -1.7 x 10-6/°C, which corresponds to ~500 m/s /°C in RV scale. In interferometer stability monitoring using a wavelength stabilized laser source, phase shift data was continuously recorded for nearly seven days. Appling a frequent calibration every 30 minutes as in typical star observations, the interferometer instability contributes less than 1.4 m/s in RV error, in a conservative estimation.

  10. High-precision buffer circuit for suppression of regenerative oscillation

    NASA Technical Reports Server (NTRS)

    Tripp, John S.; Hare, David A.; Tcheng, Ping

    1995-01-01

    Precision analog signal conditioning electronics have been developed for wind tunnel model attitude inertial sensors. This application requires low-noise, stable, microvolt-level DC performance and a high-precision buffered output. Capacitive loading of the operational amplifier output stages due to the wind tunnel analog signal distribution facilities caused regenerative oscillation and consequent rectification bias errors. Oscillation suppression techniques commonly used in audio applications were inadequate to maintain the performance requirements for the measurement of attitude for wind tunnel models. Feedback control theory is applied to develop a suppression technique based on a known compensation (snubber) circuit, which provides superior oscillation suppression with high output isolation and preserves the low-noise low-offset performance of the signal conditioning electronics. A practical design technique is developed to select the parameters for the compensation circuit to suppress regenerative oscillation occurring when typical shielded cable loads are driven.

  11. High-precision thermal and electrical characterization of thermoelectric modules

    SciTech Connect

    Kolodner, Paul

    2014-05-15

    This paper describes an apparatus for performing high-precision electrical and thermal characterization of thermoelectric modules (TEMs). The apparatus is calibrated for operation between 20 °C and 80 °C and is normally used for measurements of heat currents in the range 0–10 W. Precision thermometry based on miniature thermistor probes enables an absolute temperature accuracy of better than 0.010 °C. The use of vacuum isolation, thermal guarding, and radiation shielding, augmented by a careful accounting of stray heat leaks and uncertainties, allows the heat current through the TEM under test to be determined with a precision of a few mW. The fractional precision of all measured parameters is approximately 0.1%.

  12. High Precision Assembly Line Synthesis for Molecules with Tailored Shapes

    PubMed Central

    Burns, Matthew; Essafi, Stephanie; Bame, Jessica R.; Bull, Stephanie P.; Webster, Matthew P.; Balieu, Sebastien; Dale, James W.; Butts, Craig P.; Harvey, Jeremy N.; Aggarwal, Varinder K.

    2014-01-01

    Molecular assembly lines, where molecules undergo iterative processes involving chain elongation and functional group manipulation are hallmarks of many processes found in Nature. We have sought to emulate Nature in the development of our own molecular assembly line through iterative homologations of boronic esters. Here we report a reagent (α-lithioethyl triispopropylbenzoate) which inserts into carbon-boron bonds with exceptionally high fidelity and stereocontrol. Through repeated iteration we have converted a simple boronic ester into a complex molecule (a carbon chain with ten contiguous methyl groups) with remarkably high precision over its length, its stereochemistry and therefore its shape. Different stereoisomers were targeted and it was found that they adopted different shapes (helical/linear) according to their stereochemistry. This work should now enable scientists to rationally design and create molecules with predictable shape, which could have an impact in all areas of molecular sciences where bespoke molecules are required. PMID:25209797

  13. Preparation of cold molecules for high-precision measurements

    NASA Astrophysics Data System (ADS)

    Wall, T. E.

    2016-12-01

    Molecules can be used to test fundamental physics. Such tests often require cold molecules for detailed spectroscopic analysis. Cooling internal degrees of freedom provides a high level of state-selectivity, with large populations in the molecular states of interest. Cold translational motion allows slow, bright beams to be created, allowing long interaction times. In this tutorial article we describe the common techniques for producing cold molecules for high-precision spectroscopy experiments. For each technique we give examples of its application in experiments that use molecular structure to probe fundamental physics, choosing one experiment in particular as a case study. We then discuss a number of new techniques, some currently under development, others proposed, that promise high flux sources of cold molecules applicable to precise spectroscopic tests of fundamental physics.

  14. High precision u/th dating of first Polynesian settlement.

    PubMed

    Burley, David; Weisler, Marshall I; Zhao, Jian-xin

    2012-01-01

    Previous studies document Nukuleka in the Kingdom of Tonga as a founder colony for first settlement of Polynesia by Lapita peoples. A limited number of radiocarbon dates are one line of evidence supporting this claim, but they cannot precisely establish when this event occurred, nor can they afford a detailed chronology for sequent occupation. High precision U/Th dates of Acropora coral files (abraders) from Nukuleka give unprecedented resolution, identifying the founder event by 2838±8 BP and documenting site development over the ensuing 250 years. The potential for dating error due to post depositional diagenetic alteration of ancient corals at Nukuleka also is addressed through sample preparation protocols and paired dates on spatially separated samples for individual specimens. Acropora coral files are widely distributed in Lapita sites across Oceania. U/Th dating of these artifacts provides unparalleled opportunities for greater precision and insight into the speed and timing of this final chapter in human settlement of the globe.

  15. A high precision semi-analytic mass function

    NASA Astrophysics Data System (ADS)

    Del Popolo, Antonino; Pace, Francesco; Le Delliou, Morgan

    2017-03-01

    In this paper, extending past works of Del Popolo, we show how a high precision mass function (MF) can be obtained using the excursion set approach and an improved barrier taking implicitly into account a non-zero cosmological constant, the angular momentum acquired by tidal interaction of proto-structures and dynamical friction. In the case of the ΛCDM paradigm, we find that our MF is in agreement at the 3% level to Klypin's Bolshoi simulation, in the mass range Mvir = 5 × 109 h‑1Msolar–‑5 × 1014 h‑1Msolar and redshift range 0 lesssim z lesssim 10. For z = 0 we also compared our MF to several fitting formulae, and found in particular agreement with Bhattacharya's within 3% in the mass range 1012–1016 h‑1Msolar. Moreover, we discuss our MF validity for different cosmologies.

  16. High precision variational calculations of few-electron atoms

    NASA Astrophysics Data System (ADS)

    Bubin, Sergiy

    2015-05-01

    High precision calculations of energy levels and other properties of small atoms and ions have been a subject of fruitful interplay between the experiment and theory. However, most calculation of spectroscopic accuracy, until recently, have been possible only for two- and three-electron systems. In this talk I will report on progress toward performing high accuracy calculations of larger atomic systems (up to four-six electrons). The results of benchmark quality are attainable with the use of variational expansions in terms of all-particle explicitly correlated Gaussians, whose nonlinear variational parameters are extensively optimized. I will demonstrate what level of accuracy is available today for few-electron atoms and discuss the issues that must be overcome in order to extend the capability of the method to even larger systems. This work has been supported by the Ministry of Education and Science of Kazakhstan.

  17. The importance of high-precision hadronic calorimetry to physics

    NASA Astrophysics Data System (ADS)

    Hauptman, John

    2016-11-01

    The reconstruction and high-precision measurement of the four-vectors of W and Z decays to quarks, which constitute nearly 70% of their decay branching fractions, are critical to a high efficiency and high quality experiment. Furthermore, it is crucial that the energy resolution, and consequently the resolution on the invariant mass of the two fragmenting quarks, is comparable to the energy-momentum resolution on the other particles of the standard model, in particular, electrons, photons, and muons, at energies around 100 GeV. I show that this “unification of resolutions” on all particles of the standard model is now in sight, and will lead to excellent physics at an electron-positron collider.

  18. A high-precision polarimeter for small telescopes

    NASA Astrophysics Data System (ADS)

    Bailey, Jeremy; Cotton, Daniel V.; Kedziora-Chudczer, Lucyna

    2017-02-01

    We describe Mini-HIPPI (Miniature HIgh Precision Polarimetric Instrument), a stellar polarimeter weighing just 650 gm but capable of measuring linear polarization to ∼10-5. Mini-HIPPI is based on the use of a Ferroelectric Liquid Crystal modulator. It can easily be mounted on a small telescope and allows us to study the polarization of bright stars at levels of precision which are hitherto largely unexplored. We present results obtained with Mini-HIPPI on a 35-cm telescope. Measurements of polarized standard stars are in good agreement with predicted values. Measurements of a number of bright stars agree well with those from other high-sensitivity polarimeters. Observations of the binary system Spica show polarization variability around the orbital cycle.

  19. MultiView High Precision VLBI Astrometry at Low Frequencies

    NASA Astrophysics Data System (ADS)

    Rioja, María J.; Dodson, Richard; Orosz, Gabor; Imai, Hiroshi; Frey, Sandor

    2017-03-01

    The arrival of the Square Kilometer Array (SKA) will revitalize all aspects of Very Long Baseline Interferometry (VLBI) astronomy at lower frequencies. In the last decade, there have been huge strides toward routinely achieving high precision VLBI astrometry at frequencies dominated by tropospheric contributions, most notably at 22 GHz, using advanced phase-referencing techniques. Nevertheless, to increase the capability for high precision astrometric measurements at low radio frequencies (<8 GHz), an effective calibration strategy of the systematic ionospheric propagation effects that is widely applicable is required. Observations at low frequencies are dominated by distinct direction-dependent ionospheric propagation errors, which place a very tight limit on the angular separation of a suitable phase-referencing calibrator. The MultiView technique holds the key to compensating for atmospheric spatial-structure errors, by using observations of multiple calibrators and two-dimensional interpolation in the visibility domain. In this paper we present the first demonstration of the power of MultiView using three calibrators, several degrees from the target, along with a comparative study of the astrometric accuracy between MultiView and phase-referencing techniques. MultiView calibration provides an order of magnitude improvement in astrometry with respect to conventional phase referencing, achieving ∼100 μas astrometry errors in a single epoch of observations, effectively reaching the thermal noise limit. MultiView will achieve its full potential with the enhanced sensitivity and multibeam capabilities of SKA and the pathfinders, which will enable simultaneous observations of the target and calibrators. Our demonstration indicates that the 10 μas goal of astrometry at ∼1.6 GHz using VLBI with SKA is feasible using the MultiView technique.

  20. High-precision photometry for K2 Campaign 1

    NASA Astrophysics Data System (ADS)

    Huang, C. X.; Penev, K.; Hartman, J. D.; Bakos, G. Á.; Bhatti, W.; Domsa, I.; de Val-Borro, M.

    2015-12-01

    The two reaction wheel K2 mission promises and has delivered new discoveries in the stellar and exoplanet fields. However, due to the loss of accurate pointing, it also brings new challenges for the data reduction processes. In this paper, we describe a new reduction pipeline for extracting high-precision photometry from the K2 data set, and present public light curves for the K2 Campaign 1 target pixel data set. Key to our reduction is the derivation of global astrometric solutions from the target stamps, from which accurate centroids are passed on for high-precision photometry extraction. We extract target light curves for sources from a combined UCAC4 and EPIC catalogue - this includes not only primary targets of the K2 campaign 1, but also any other stars that happen to fall on the pixel stamps. We provide the raw light curves, and the products of various detrending processes aimed at removing different types of systematics. Our astrometric solutions achieve a median residual of ˜0.127 arcsec. For bright stars, our best 6.5 h precision for raw light curves is ˜20 parts per million (ppm). For our detrended light curves, the best 6.5 h precision achieved is ˜15 ppm. We show that our detrended light curves have fewer systematic effects (or trends, or red-noise) than light curves produced by other groups from the same observations. Example light curves of transiting planets and a Cepheid variable candidate, are also presented. We make all light curves public, including the raw and detrended photometry, at http://k2.hatsurveys.org.