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Finesse measurement for high-power optical enhancement cavity
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作者 陆心怡 柳兴 +3 位作者 田其立 王焕 汪嘉俊 颜立新 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期414-421,共8页
Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the a... Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the advantages, disadvantages, and potential limitations of several main methods from both theoretical and practical perspectives. A variant of the existing method called the free spectral range(FSR) modulation method is proposed and compared with three other finesse measurement methods, i.e., the fast-switching cavity ring-down(CRD) method, the rapidly swept-frequency(SF) CRD method, and the ringing effect method. A high-power OEC platform with a high finesse of approximately 16000 is built and measured with the four methods. The performance of these methods is compared, and the results show that the FSR modulation method and the fast-switching CRD method are more suitable and accurate than the other two methods for high-finesse OEC measurements. The CRD method and the ringing effect method can be implemented in open loop using simple equipment and are easy to perform. Additionally, recommendations for selecting finesse measurement methods under different conditions are proposed, which benefit the development of OEC and its applications. 展开更多
关键词 optical enhancement cavity finesse measurement cavity ring-down ringing effect
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Measurement of the cavity-loaded quality factor in superconducting radio-frequency systems with mismatched source impedance
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作者 Jin-Ying Ma Cheng-Ye Xu +12 位作者 An-Dong Wu Guo-Dong Jiang Yue Tao Zong-Heng Xue Long-Bo Shi Tian-Cai Jiang Zheng-Long Zhu Zi-Qin Yang Zheng Gao Lie-Peng Sun Gui-Rong Huang Feng Qiu Yuan He 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第8期12-23,共12页
The accurate measurement of parameters such as the cavity-loaded quality factor(Q_(L))and half bandwidth(f_(0.5))is essential for monitoring the performance of superconducting radio-frequency cavities.However,the conv... The accurate measurement of parameters such as the cavity-loaded quality factor(Q_(L))and half bandwidth(f_(0.5))is essential for monitoring the performance of superconducting radio-frequency cavities.However,the conventional"field decay method"employed to calibrate these values requires the cavity to satisfy a"zero-input"condition.This can be challenging when the source impedance is mismatched and produce nonzero forward signals(V_(f))that significantly affect the measurement accuracy.To address this limitation,we developed a modified version of the"field decay method"based on the cavity differential equation.The proposed approach enables the precise calibration of f_(0.5) even under mismatch conditions.We tested the proposed approach on the SRF cavities of the Chinese Accelerator-Driven System Front-End Demo Superconducting Linac and compared the results with those obtained from a network analyzer.The two sets of results were consistent,indicating the usefulness of the proposed approach. 展开更多
关键词 Loaded quality factor Field decay method Superconducting cavity MISMATCH Calibration cavity differential equation measurement Accelerator-driven system
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Application of the body of revolution finite-element method in a re-entrant cavity for fast and accurate dielectric parameter measurements
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作者 冯天琦 余承勇 +1 位作者 李恩 石玉 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期36-44,共9页
In dielectrometry,traditional analytical and numerical algorithms are difficultly employed in complex resonant cavities.For a special kind of structure(a rotating resonant cavity),the body of revolution finite-element... In dielectrometry,traditional analytical and numerical algorithms are difficultly employed in complex resonant cavities.For a special kind of structure(a rotating resonant cavity),the body of revolution finite-element method(BOR-FEM)is employed to calculate the resonant parameters and dielectric parameters.In this paper,several typical resonant structures are selected for analysis and verification.Compared with the resonance parameter values in the literature and the simulation results of commercial software,the error of the BOR-FEM calculation is less than 0.9%and a single solution time is less than 1 s.Reentrant coaxial resonant cavities loaded with dielectric materials are analyzed using this method and compared with simulation results,showing good agreement.Finally,in this paper,the established BOR-FEM method is successfully applied with a machined cavity for the accurate measurement of the complex dielectric constant of dielectric materials.The test specimens were machined from polytetrafluoroethylene,fused silica and Al_(2)O_(3),and the test results showed good agreement with the literature reference values. 展开更多
关键词 MICROWAVE resonance method dielectric measurement coaxial resonant cavity
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Teleportation of N-qubit W State without Bell-State Measurement via Selective Resonant Interaction in Cavity QED 被引量:1
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作者 钟文学 耿珺 +1 位作者 程广玲 陈爱喜 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第8期253-256,共4页
We present a scheme in which the N-atom W state is teleported by employing the selective interactionof a cavity field with a driven three-level atom in the A configuration and detecting a single atom in one of the gro... We present a scheme in which the N-atom W state is teleported by employing the selective interactionof a cavity field with a driven three-level atom in the A configuration and detecting a single atom in one of the groundstates.The long-lived W state is teleported from atom A to atom B when the atoms B and A are sent through acavity successively and atom A is then detected.The advantage is that the present one does not involve the Bell-statemeasurement and is robust against the atomic spontaneous emission. 展开更多
关键词 TELEPORTATION W state bell-state measurement selective resonant interaction
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Influence of selective atomic measurement on the entanglement properties of a two-atom outside cavity
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作者 卢道明 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第3期43-47,共5页
Considering three two-level atoms initially in the W or Greenberger-Horne-Zeilinger (GHZ) state, one of the three atoms is put into an initially coherent light cavity and made to resonantly interact with the cavity.... Considering three two-level atoms initially in the W or Greenberger-Horne-Zeilinger (GHZ) state, one of the three atoms is put into an initially coherent light cavity and made to resonantly interact with the cavity. The twoatom entanglement evolution outside the cavity is investigated. The influences of state-selective measurement of the atom inside the cavity and strength of the light field on the two-atom entanglement evolution outside the cavity are discussed. The results obtained from the numerical method show that the two-atom entanglement outside the cavity is strengthened through state-selective measurement of the atom inside the cavity. In addition, the strength of the light field also influences the two-atom entanglement properties. 展开更多
关键词 quantum optics two-level atom selective atomic measurement ENTANGLEMENT
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Measurement of Cavity Loss and Quasi-Fermi-Level Separation for Fabry-Pérot Semiconductor Lasers
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作者 韩春林 刘瑞喜 +2 位作者 国伟华 于丽娟 黄永箴 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第8期789-793,共5页
A fitting process is used to measure the cavity loss and the quasi Fermi level separation for Fabry Pérot semiconductor lasers.From the amplified spontaneous emission (ASE) spectrum,the gain spectrum and sing... A fitting process is used to measure the cavity loss and the quasi Fermi level separation for Fabry Pérot semiconductor lasers.From the amplified spontaneous emission (ASE) spectrum,the gain spectrum and single pass ASE obtained by the Cassidy method are applied in the fitting process.For a 1550nm quantum well InGaAsP ridge waveguide laser,the cavity loss of about ~24cm -1 is obtained. 展开更多
关键词 semiconductor lasers measurement technique cavity loss
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Optimization of the cavity beam-position monitor system for the Shanghai soft X-ray free-electron laser user facility 被引量:3
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作者 Jian Chen Yong-Bin Leng +2 位作者 Lu-Yang Yu Long-Wei Lai Ren-Xian Yuan 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2022年第10期22-32,共11页
To achieve high-efficiency operation of the highgain free-electron laser(FEL),the electron beams and radiated photon beams need to be overlapped precisely and pass through the entire undulator section.Therefore,a high... To achieve high-efficiency operation of the highgain free-electron laser(FEL),the electron beams and radiated photon beams need to be overlapped precisely and pass through the entire undulator section.Therefore,a high-resolution beam-position monitor(BPM)is required.A cavity BPM(CBPM)with a resonant cavity structure was developed and used in the Shanghai Soft X-ray FEL(SXFEL)test facility and can achieve a position resolution of<1μm.The construction and operation of the SXFEL user facility also bring about higher requirements for beamposition measurement.In this case,the factors that affect the performance of the CBPM system were further analyzed.These included the amplitude and phase stability of the local oscillator,stability of the trigger signal,performance of the radio frequency front-end,signal processing electronics,and signal processing algorithms.Based on the upgrade and optimization of the system,a beam test platform was built at the end of the linear acceleration section of the SXFEL,and the experimental results show that the position resolution of the system can reach 177 nm at a bunch charge of 500 pC,and the dynamic range is controlled within±300μm,and the relative measurement uncertainty of the bunch charge can reach 0.021%,which are significant improvements compared to the attributes of the previous system. 展开更多
关键词 cavity BPM SXFEL System optimization Position resolution measurement uncertainty ALGORITHM
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A novel scheme of hybrid entanglement swapping and teleportation using cavity QED in the small and large detuning regimes and quasi-Bell state measurement method 被引量:1
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作者 R Pakniat M K Tavassoly M H Zandi 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第10期45-51,共7页
We outline a scheme for entanglement swapping based on cavity QED as well as quasi-Bell state measurement(quasiBSM) methods. The atom–field interaction in the cavity QED method is performed in small and large detunin... We outline a scheme for entanglement swapping based on cavity QED as well as quasi-Bell state measurement(quasiBSM) methods. The atom–field interaction in the cavity QED method is performed in small and large detuning regimes.We assume two atoms are initially entangled together and, distinctly two cavities are prepared in an entangled coherent–coherent state. In this scheme, we want to transform entanglement to the atom-field system. It is observed that, the fidelities of the swapped entangled state in the quasi-BSM method can be compatible with those obtained in the small and large detuning regimes in the cavity QED method(the condition of this compatibility will be discussed). In addition, in the large detuning regime, the swapped entangled state is obtained by detecting and quasi-BSM approaches. In the continuation,by making use of the atom–field entangled state obtained in both approaches in a large detuning regime, we show that the atomic as well as field states teleportation with complete fidelity can be achieved. 展开更多
关键词 entanglement swapping quantum teleportation cavity QED quasi-bell state measurement
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Cavity Ring-Down Spectroscopy Measurements of Ambient NO3 and N2O5 被引量:1
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作者 Hao Wu Jian Chen +2 位作者 An-wen Liu Shui-ming Hu Jing-song Zhang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2020年第1期1-7,共7页
NO3 and N2O5 are important participants in nocturnal atmospheric chemical processes,and their concentrations are of great significance in the study of the mechanism of nocturnal atmospheric chemical reactions.A two-ch... NO3 and N2O5 are important participants in nocturnal atmospheric chemical processes,and their concentrations are of great significance in the study of the mechanism of nocturnal atmospheric chemical reactions.A two-channel diode laser based cavity ring-down spectroscopy(CRDS)instrument was developed to monitor the concentrations of NO3 and N2O5 in the atmosphere.The effective absorption length ratio and the total loss coefficient of the instrument were calibrated using laboratory standard samples.The effective absorption cross section of NO3 at 662 nm was derived.A detection sensitivity of 1.1 pptv NO3 in air was obtained at a time resolution of 1 s.N2O5 was converted to NO3 and detected online in the second CRDS channel.The instrument was used to monitor the concentrations of NO3 and N2O5 in the atmosphere of winter in Hefei in real time.By comparing the concentration changes of pollutants such as nitrogen oxides,ozone,PM2:5 in a rapid air cleaning process,the factors affecting the concentrations of NO3 and N2O5 in the atmosphere were discussed. 展开更多
关键词 cavity ring-down spectroscopy Nitrate radical Dinitrogen pentoxide Field measurement
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Entanglement swapping without joint measurement via a ∧-type atom interacting with bimodal cavity field
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作者 林秀 李洪才 +1 位作者 杨榕灿 黄志平 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第4期919-922,共4页
This paper proposes a scheme for realizing entanglement swapping in cavity QED. The scheme is based on the resonant interaction of a two-mode cavity field with a ∧-type three-level atom. In contrast with the previous... This paper proposes a scheme for realizing entanglement swapping in cavity QED. The scheme is based on the resonant interaction of a two-mode cavity field with a ∧-type three-level atom. In contrast with the previously proposed schemes, the present scheme is ascendant, since the fidelity is 1.0 and the joint measurement isn't needed. And the scheme is experimentally feasible based on the current cavity QED technique. 展开更多
关键词 entanglement swapping ∧-type atom two-mode cavity field joint measurement
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Faithfully probabilistic teleportation of an unknown atomic state and cavity field state with a single measurement
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作者 杨贞标 吴怀志 +2 位作者 苏万钧 钟志荣 郑仕标 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第11期3391-3395,共5页
This paper shows that, based on the single-photon JC model depicting the resonant interaction of a two-level atom with a single cavity mode, an unknown atomic state and cavity photon superposition state can be faithfu... This paper shows that, based on the single-photon JC model depicting the resonant interaction of a two-level atom with a single cavity mode, an unknown atomic state and cavity photon superposition state can be faithfully telcported with only a single measurement. The scheme is probabilistie, its success lies on the event that the sender atom (or the medi-atom, for teleportation of cavity field state) is detected in the higher state. The scheme is in contrast to the previous ones of using a maximally two-particle entangled state as quantum channel. 展开更多
关键词 faithful teleportation a single measurement cavity QED
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Scheme for teleportation of an unknown atomic state via a cluster state in cavity QED 被引量:3
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作者 曹卓良 李大创 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第1期55-59,共5页
This paper proposes an experimentally feasible scheme for teleportation of an unknown two-atom entangled state, where a cluster state is used as the quantum channel. This scheme does not need any joint measurement. In... This paper proposes an experimentally feasible scheme for teleportation of an unknown two-atom entangled state, where a cluster state is used as the quantum channel. This scheme does not need any joint measurement. In addition, the successful probability and fidelity of teleportation can both reach 1.0. The current scheme can be realized within the current experimental technology. 展开更多
关键词 quantum teleportation joint measurement quantum controlled phase gate cavity QED
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Approximate and Conditional Teleportation of an Unknown Atomic State Without Bell-State Measurement with Two-Photon Interaction 被引量:2
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作者 CHEN Chang-Yong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第1期79-82,共4页
A scheme for approximately and conditionally teleporting an unknown atomic state via two-photon interaction in cavity QED is proposed. It is the extension of the scheme of Ref. [11] [Phys. Rev. A 69 (2004) 064302], ... A scheme for approximately and conditionally teleporting an unknown atomic state via two-photon interaction in cavity QED is proposed. It is the extension of the scheme of Ref. [11] [Phys. Rev. A 69 (2004) 064302], which is based on Jaynes-Cummings model in QED and where only a time point of system evolution and the corresponding fidelity implementing the teleportation are given. In our scheme, the two-photon interaction Jaynes-Cummings model is used to realize the approximate and conditional teleportation. Our scheme does not involve the Bell-state measurement and an additional atom, only requiring two atoms and one single-mode cavity. The fidelity of the scheme is higher than that of Ref. [11]. The scheme may be generalized to not only the teleportation of the state of a cavity mode to another mode by means of a single atom but also the teleportation of the state of a trapped ion. 展开更多
关键词 TELEPORTATION bell-state measurement cavity QED two-photon interaction
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Comment on “Approximate and Conditional Teleportation of an Unknown Atomic State Without Bell-State Measurement with Two-Photon Interaction” 被引量:1
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作者 A.D.dSouza W.B.Cardoso +1 位作者 A.T.Avelar B.Baseia 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第7期41-44,共4页
In a previous work [Commun. Theor. Phys. 45 (2006) 79] a scheme was presented for approximate and conditional teleportation of an unknown atomic state in a QED-cavity without Bell-state measurement via two-photon Ja... In a previous work [Commun. Theor. Phys. 45 (2006) 79] a scheme was presented for approximate and conditional teleportation of an unknown atomic state in a QED-cavity without Bell-state measurement via two-photon Jaynes-Cummings model in the effective Hamiltonian approach. This comment presents an alternative method, based on the so called "full two-photon Jaynes-Cummings Hamiltonian approach". Accordingly, it describes the evolution of the two-photon degenerate process for arbitrary average photon number inside the cavity, as the correct way to implement teleportation in this scenario. 展开更多
关键词 TELEPORTATION bell-state measurement cavity QED two-photon interaction
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Probabilistic teleportation of an unknown N-atom state using a two-atom nonmaximally entangled state in cavity QED 被引量:1
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作者 林秀 李洪才 杨榕灿 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第3期624-629,共6页
We present a scheme for realizing probabilistic teleportation of an unknown N-atom state via cavity QED. This scheme requires only a nonmaximally entangled pair to be used as a quantum channel, so the requirement of e... We present a scheme for realizing probabilistic teleportation of an unknown N-atom state via cavity QED. This scheme requires only a nonmaximally entangled pair to be used as a quantum channel, so the requirement of entanglement is reduced. In addition, our scheme does not involve the Bell-state measurement and is insensitive to the cavity decay, which is important from the experimental point of view. If the quantum channel is a two-atom maximally entangled state, teleportation of an unknown N-atom state can be realized by a simpler scheme via cavity QED. 展开更多
关键词 probabilistic teleportation without bell-state measurement atomic entangled state nonmaximally entangled pair cavity QED
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Teleportation of an Unknown Atomic Entangled State Without Any Joint Bell-state Measurement via a Cluster State 被引量:1
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作者 CAO Zhuo-Liang LI Da-Chuang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第2期369-372,共4页
An experimentally feasible scheme for teleportation of an unknown two-atom entangled state is proposed. Our scheme uses a duster state as the quantum channel, where we do not need any joint Bell-state measurement. Mor... An experimentally feasible scheme for teleportation of an unknown two-atom entangled state is proposed. Our scheme uses a duster state as the quantum channel, where we do not need any joint Bell-state measurement. Moreover the successful probability and fidelity of teleportation can both reach 1.0. The current scheme can be realized within the current experimental technology. 展开更多
关键词 quantum teleportation joint bell-state measurement cavity QED quantum controlled phase gate
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Indicator Selection for Quality Measurement in Maternal Neonatal and Child Health Services: Application of Random Forest Classifier
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作者 Sarah Nyanjara Dina Machuve Pirkko Nykanen 《Journal of Computer and Communications》 2023年第7期74-87,共14页
Quality of Maternal, Neonatal and Child (MNCH) care is an important aspect in ensuring healthy outcomes and survival of mothers and children. To maintain quality in health services provided, organizations and other st... Quality of Maternal, Neonatal and Child (MNCH) care is an important aspect in ensuring healthy outcomes and survival of mothers and children. To maintain quality in health services provided, organizations and other stakeholders in maternal and child health recommend regular quality measurement. Quality indicators are the key components in the quality measurement process. However, the literature shows neither an indicator selection process nor a set of quality indicators for quality measurement that is universally accepted. The lack of a universally accepted quality indicator selection process and set of quality indicators results in the establishment of a variety of quality indicator selection processes and several sets of quality indicators whenever the need for quality measurement arises. This adds extra processes that render quality measurement process. This study, therefore, aims to establish a set of quality indicators from a broad set of quality indicators recommended by the World Health Organization (WHO). The study deployed a machine learning technique, specifically a random forest classifier to select important indicators for quality measurement. Twenty-nine indicators were identified as important features and among those, eight indicators namely maternal mortality ratio, still-birth rate, delivery at a health facility, deliveries assisted by skilled attendants, proportional breach delivery, normal delivery rate, born before arrival rate and antenatal care visit coverage were identified to be the most important indicators for quality measurement. 展开更多
关键词 Indicator Selection Machine Learning Quality measurement Random Forest Quality Indicators Maternal Care Quality Neonatal Care Quality
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External-cavity birefringence feedback effects of microchip Nd:YAG laser and its application in angle measurement 被引量:2
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作者 任成 谈宜东 张书练 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第8期3438-3443,共6页
External-cavity birefringence feedback effects of the microchip Nd:YAG laser are presented. When a birefringence element is placed in the external feedback cavity of the laser, two orthogonally polarized laser beams ... External-cavity birefringence feedback effects of the microchip Nd:YAG laser are presented. When a birefringence element is placed in the external feedback cavity of the laser, two orthogonally polarized laser beams with a phase difference are output. The phase difference is twice as large as the phase retardation in the external cavity along the two orthogonal directions. The variable extra-cavity birefringence, caused by rotation of the external-cavity birefringenee element, results in tunable phase difference between the two orthogonally polarized beams. This means that the roll angle information has been translated to phase difference of two output laser beams. A theoretical analysis based on the Fabry-Perot cavity equivalent model and refractive index ellipsoid is presented, which is in good agreement with the experimental results. This phenomenon has potential applications for roll angle measurement. 展开更多
关键词 microchip laser external-cavity birefringence feedback orthogonally polarized lasers angle measurement
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Scheme for direct measurement of Wigner function in two-mode cavity QED driven by classical fields
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作者 吴怀志 杨贞标 郑仕标 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第12期255-262,共8页
We propose a scheme for the direct measurement of Wigner function in two-mode cavity QED. The atoms are sent to resonantly interact with two orthogonally polarized cavity modes in the presence of strong classical fiel... We propose a scheme for the direct measurement of Wigner function in two-mode cavity QED. The atoms are sent to resonantly interact with two orthogonally polarized cavity modes in the presence of strong classical field. The probability of measuring the atom in the ground state directly gives the useful information of the cavity field. This method can be used for quantum non-demolition measurement of the photon number. 展开更多
关键词 two-mode cavity Wigner function quantum non-demolition measurement
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Faithful Teleportation of an Unknown Atomic-Entangled State Without Bell-State Measurement
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作者 LIN Xiu LI Hong-Cai YANG Rong-Can HUANG Zhi-Ping 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第3期621-624,共4页
An alternative scheme is proposed for teleportation of an unknown atomic-entangled state. The scheme is based on the resonant interaction of a two-mode cavity field with a A-type three-level atom. In contrast with the... An alternative scheme is proposed for teleportation of an unknown atomic-entangled state. The scheme is based on the resonant interaction of a two-mode cavity field with a A-type three-level atom. In contrast with the previously proposed scheme of [Commun. Theor. Phys. 47 (2007) 253], the present scheme is ascendant, since the fidelity is 1.0 in principle similarly without the Bell-state measurement. The scheme may be generalized to not only the teleportation of the cavity-mode-entangled-state but also the teleportation of the multi-atomic entangled states included in generalized GHZ states. And the scheme is experimentally feasible based on the current cavity QED technique. 展开更多
关键词 TELEPORTATION A-type atom two-mode cavity field bell-state measurement
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