In this paper,we investigate the phenomena of electromagnetically induced transparency and the generation of second-order sideband in a Laguerre–Gaussian cavity optorotational system with a Kerr nonlinear medium.Usin...In this paper,we investigate the phenomena of electromagnetically induced transparency and the generation of second-order sideband in a Laguerre–Gaussian cavity optorotational system with a Kerr nonlinear medium.Using the perturbation method,we analyze the first-and second-order sideband generations in the output field from the system under the actions of a strong control field and a weak probe field.Numerical simulations show that the Kerr nonlinearity can lead to the occurrence of the asymmetric line shape in the transmission of the probe field.Comparing with traditional scheme for generating the second-order sideband,our spectral shape of the second-order sideband is amplified and becomes asymmetric,which has potential applications in precision measurement,high-sensitivity devices,and frequency conversion.展开更多
Fabrication-friendly superconducting qubits continue to be a leading candidate for scalable quantum computing.Recent developments in tunable couplers have significantly advanced the progress toward practical quantum p...Fabrication-friendly superconducting qubits continue to be a leading candidate for scalable quantum computing.Recent developments in tunable couplers have significantly advanced the progress toward practical quantum processors.However,high-performance quantum control,particularly two-qubit gates,depends on the delicate tuning of the coupler spectrum,as misalignment can lead to undesirable phenomena such as frequency crowding,which may cause errors including state leakage.Here,we propose an efficient method for characterizing the coupler spectrum through sideband drivings,obviating the need for additional components in current quantum processors.We demonstrate this technique experimentally by employing both continuous-wave and pulsed measurement protocols,successfully extracting the coupler spectrum.Furthermore,by utilizing the measured coupler spectrum,we calibrate the frequency dependence of the effective coupling strength between two qubits linked by the coupler.The proposed approach offers significant practical benefits,enabling the efficient characterization of the coupler spectrum in existing quantum architectures,thus paving the way for enhanced quantum control and scalability.展开更多
Sideband cooling is a key technique for improving the performance of optical atomic clocks by preparing cold atoms and single ions into the ground vibrational state.In this work,we demonstrate detailed experimental re...Sideband cooling is a key technique for improving the performance of optical atomic clocks by preparing cold atoms and single ions into the ground vibrational state.In this work,we demonstrate detailed experimental research on pulsed Raman sideband cooling in a 171 Yb optical lattice clock.A sequence comprised of interleaved 578 nm cooling pulses resonant on the 1st-order red sideband and 1388 nm repumping pulses is carried out to transfer atoms into the motional ground state.We successfully decrease the axial temperature of atoms in the lattice from 6.5μK to less than 0.8μK in the trap depth of 24μK,corresponding to an average axial motional quantum number<nz><0.03.Rabi oscillation spectroscopy is measured to evaluate the effect of sideband cooling on inhomogeneous excitation.The maximum excitation fraction is increased from 0.8 to 0.86,indicating an enhancement in the quantum coherence of the ensemble.Our work will contribute to improving the instability and uncertainty of Yb lattice clocks.展开更多
Time?variant excitations in planetary gear trains can cause excessive noise and vibration and even damage the system on a permanent basis. This paper focuses on the elastic vibrations of a helical planetary ring gear ...Time?variant excitations in planetary gear trains can cause excessive noise and vibration and even damage the system on a permanent basis. This paper focuses on the elastic vibrations of a helical planetary ring gear subjected to mesh and planet?pass excitations. Motivated by the structure, excitation and deformation symmetries, this paper proposes dual?frequency superposition and modulation methods to capture the mesh and sideband vibrations. The transi?tion between ring gear tooth and planet is introduced to address the excitations and vibrations. The phasing e ect of ring gear tooth and planet on various deformations is formulated. The inherent connections between the two types of vibrations are identified. The vibrations share identical exciting rules and the wavenumber and modulating signal order both equal the linear combination of tooth and planet counts. The results cover in?plane bending and extensional, out?of?plane bending and torsional deformations. Main findings are verified by numerical calculation and comparisons with the open literature. The analytical expressions can be used to determine whether the sideband is caused by component fault or only by elastic vibration. The methods can be extended to other power?transmission systems because little restriction is imposed during the analysis.展开更多
In the unresolved sideband regime,we propose a scheme for cooling mechanical resonator close to its ground state in a three-cavity optomechanical system,where the auxiliary cavities are indirectly connected with the m...In the unresolved sideband regime,we propose a scheme for cooling mechanical resonator close to its ground state in a three-cavity optomechanical system,where the auxiliary cavities are indirectly connected with the mechanical resonator through standard optomechanical subsystem.The standard optomechanical subsystem is driven by a strong pump laser field.With the help of the auxiliary cavities,the heating process is suppressed and the cooling process of the mechanical resonator is enhanced.More importantly,the average phonon number is much less than 1 in a larger range.This means that the mechanical resonator can be cooled down to its ground state.All these interesting features will significantly promote the physical realization of quantum effects in multi-cavity optomechanical systems.展开更多
The glasses of 59 5H 3BO 3 40XF n 0 5Eu 2O 3 (X=Ca, Mg, Y, Pb, n =2 or 3) were prepared. The measurement of phonon sideband was performed. The higher energy range of phonon sideband spectra was fitted ...The glasses of 59 5H 3BO 3 40XF n 0 5Eu 2O 3 (X=Ca, Mg, Y, Pb, n =2 or 3) were prepared. The measurement of phonon sideband was performed. The higher energy range of phonon sideband spectra was fitted by Gaussian function, and the electron phonon coupling constant was calculated. The decreasing order of electron phonon coupling constant is from CaF 2, YF 3, MgF 2 to PbF 2, and the phonon sideband spectra are coincide with Raman scattering spectra.展开更多
We develop a simple and practical scheme to apply sideband cooling to a cloud of rubidium atoms. A sample containing 4 × 10^（70） ^（87）Rb is trapped in a far red detuned optical lattice. Through optimizing the...We develop a simple and practical scheme to apply sideband cooling to a cloud of rubidium atoms. A sample containing 4 × 10^（70） ^（87）Rb is trapped in a far red detuned optical lattice. Through optimizing the relevant parameters, i.e., laser detuning, magnetic field, polarization, and duration time, a temperature around 1.5 μK and phase space density close to 1/500 are achieved. Compared with polarization gradient cooling, the temperature decreases by around one order of magnitude. This technique could be used in high precision measurement such as atomic clocks and atom interferometer. It could also serve as a precooling means before evaporation cooling in a dipole trap, and may be a promising method of achieving quantum degeneracy with purely optical means.展开更多
Sideband manipulation of population inversion in a three-level A atomic configuration is investigated theoretically. Compared with the case of a nearly monochromatic field, a population inversion between an excited st...Sideband manipulation of population inversion in a three-level A atomic configuration is investigated theoretically. Compared with the case of a nearly monochromatic field, a population inversion between an excited state and a ground state has been found in a wide sideband intensity range by increasing the difference in frequency between three components. Furthermore, the population inversion can be controlled by the sum of the relative phases of the sideband components of the trichromatic pump field with respective to the phase of the central component. Changing the sum phase from 0 to π, the population inversion between the excited state and the ground state can increase within nearly half of the sideband intensity range. At the same time, the sideband intensity range that corresponds to the system exhibiting inversion ρ00 〉 ρ11 also becomes wider evidently.展开更多
We theoretically investigated a second-order optomechanical-induced transparency(OMIT) process of a hybrid optomechanical system(COMS), which a Bose-Einstein condensate(BEC) in the presence of atom-atom interaction tr...We theoretically investigated a second-order optomechanical-induced transparency(OMIT) process of a hybrid optomechanical system(COMS), which a Bose-Einstein condensate(BEC) in the presence of atom-atom interaction trapped inside a cavity with a moving end mirror. The advantage of this hybrid COMS over a bare COMS is that the frequency of the second mode is controlled by the s-wave scattering interaction. Based on the traditional linearization approximation, we derive analytical solutions for the output transmission intensity of the probe field and the dimensionless amplitude of the second-order sideband(SS). The numerical results show that the transmission intensity of the probe field and the dimensionless amplitude of the SS can be controlled by the s-wave scattering frequency. Furthermore, the control field intensities,the effective detuning, the effective coupling strength of the cavity field with the Bogoliubov mode are used to control the transmission intensity of the probe field and the dimensionless amplitude of the SS.展开更多
study drifting modulation instability(MI)that exhibits asymmetric discrete spectrum recurrences in the nonlinear stage within the framework of the focusing nonlinear Schr¨odinger equation.We demonstrate that such...study drifting modulation instability(MI)that exhibits asymmetric discrete spectrum recurrences in the nonlinear stage within the framework of the focusing nonlinear Schr¨odinger equation.We demonstrate that such drifting MI can arise either from the local periodization of general breathers or from numerical simulations starting with an initial modulation containing asymmetric sidebands.展开更多
As an important quantum communication protocol,quantum teleportation has broad applications in quantum information science and technology.For the application,it is essential to enhance the ability of quantum teleporta...As an important quantum communication protocol,quantum teleportation has broad applications in quantum information science and technology.For the application,it is essential to enhance the ability of quantum teleportation by teleporting multiple quantum states simultaneously.Here,we experimentally demonstrate deterministic quantum teleportation of multiple sideband qumodes of coherent states,which corresponds to teleporting multiple quantum states simultaneously,with the assistance of continuous-variable(CV)quantum entanglement.By fine-tuning the phases of two classical channels according to different adjustable frequencies,we successfully realize deterministic CV quantum teleportation with up to 5 sideband qumodes simultaneously within the frequency bandwidth of 24 MHz.We show that the number of teleported multiple qumodes is controllable by changing the phases of two classical channels.The obtained fidelities of output multiple qumodes are around 70%,which are all beyond the non-cloning limit.The results present a novel method for quantum teleportation of multiple quantum states simultaneously and take a crucial step in enhancing the teleporting ability of quantum teleportation.展开更多
Gearboxes,known for their compact size and stable transmission capability,are widely used as power transmission structures in various types of mechanical equipment,such as wind turbines,helicopters,and special vehicle...Gearboxes,known for their compact size and stable transmission capability,are widely used as power transmission structures in various types of mechanical equipment,such as wind turbines,helicopters,and special vehicles.However,due to harsh and non-stationary working conditions,gear surfaces often deteriorate,leading to faults such as wear,pitting,and cracking.Therefore,it is vital to monitor the working status of gearboxes and diagnose gear faults as early as possible.Gear faults can induce characteristic modulation effects near the gear meshing frequency(GMF),resulting in the appearance of faultinduced sidebands in a vibration spectrum.Extraction of these sidebands allows for the diagnosis of gear faults in a gearbox.However,when faced with a planetary gearbox having a complex configuration,strong background noise and additional faultunrelated sidebands can interfere with fault-induced sidebands,making accurate diagnosis difficult.To address these challenging issues,this paper proposes a novel fault-induced gear meshing modulation sideband extraction method.In the process,the sidebands directly related to the gear fault near the GMF are first identified and then extracted by a variational harmonic mode decomposition(VHMD)method.Accordingly,a fault-related gear meshing modulation component(GMMC)can be accurately reconstructed by summing up the extracted fault-induced sidebands.Using the GMMC,the gear fault severity can be assessed by evaluating its amplitude modulation(AM)effect.The superior performance of the proposed method is finally demonstrated by experimental data.展开更多
Constructing large-scale quantum resources is an important foundation for further improving the efficiency and scalability of quantum communication.Here,we present an efficient extraction and stable control scheme of ...Constructing large-scale quantum resources is an important foundation for further improving the efficiency and scalability of quantum communication.Here,we present an efficient extraction and stable control scheme of 40 pairs of entangled sideband modes from the squeezed light by specially designing an optical parametric oscillator.Utilizing the low-loss optical frequency comb control technology and the local cross-correlation algorithm,we model and manage the efficient separation process of the entangled sideband modes facilitated by the optical filtering cavities,and a maximum entanglement level of 6.5 dB is achieved.The feasibility of large-capacity quantum dense coding based on these entangled sideband modes is proved experimentally,which is of great significance for optimizing the utilization of quantum resources,thereby contributing to the advancement of largecapacity quantum communication networks and enabling the realization of more secure and efficient quantum communication systems.展开更多
Superconducting optomechanical circuits enable frequency mixing of optical and mechanical modes,facilitating the generation of microwave frequency combs.However,such optomechanical combs suffer from frequency fluctuat...Superconducting optomechanical circuits enable frequency mixing of optical and mechanical modes,facilitating the generation of microwave frequency combs.However,such optomechanical combs suffer from frequency fluctuations,requiring their stabilization for applications in precision sensing and signal processing.Here,we investigate the sideband injection locking of microwave frequency combs in a niobium-based superconducting optomechanical circuit.By strongly driving the device with a blue-detuned pump to induce parametric instability and introducing an additional tone near individual comb peaks,we study how the locking range varies with the power,the frequency position,and the sweep direction of the injection tone.The locking responses show interesting features such as injection hysteresis,which cannot be explained by existing models.Numerical simulations of the classical optomechanical equations implementing a cubic mechanical nonlinearity show that the nonlinearity contributes to broadening the locking range.We also characterize the Allan deviations and phase noise of the injection-locked combs for different injection frequencies,demonstrating enhanced stability performance.Our results lay the foundation for the utilization of optomechanical combs for applications in nanomechanical sensing and cryogenic microwave pulse generation.展开更多
Polarization fluctuation induced noise and backscattering-induced noise are the dominant noises in resonant fiber optic gyroscopes. This Letter proposes a new method to suppress the carrier and backscattering induced ...Polarization fluctuation induced noise and backscattering-induced noise are the dominant noises in resonant fiber optic gyroscopes. This Letter proposes a new method to suppress the carrier and backscattering induced noise by the sideband locking technique. Besides choosing an optimized modulation depth and different clockwise and counterclockwise modulation frequencies, the sideband is locked to the cavity resonance. With the proper modulation frequency, the carrier frequency component locates at a position far away from the resonant frequency, and then it is suppressed by the cavity itself, which can be taken as a bandpass filter. The amplitude of the carrier frequency can be suppressed by 20–25 d B additionally by the cavity and the total intensity suppression ratio can reach 115.74 d B. The backscattering induced noise can be eliminated for the adoption of different frequencies. The method can realize a stable and high suppression ratio without high requirements for parameter accuracy or device performance.展开更多
A new technique to generate a millimeter（mm）-wave carrier of 32.57 GHz（f_（LO）=10.85 GHz） with single sideband modulation（SSB） for radio-over-fiber（RoF） systems is experimentally demonstrated by using stimula...A new technique to generate a millimeter（mm）-wave carrier of 32.57 GHz（f_（LO）=10.85 GHz） with single sideband modulation（SSB） for radio-over-fiber（RoF） systems is experimentally demonstrated by using stimulated Brillouin scattering（SBS）.The SSB is realized by directly amplifying the ＋3rd sideband of the modulated optical carrier in the process of SBS.The pump wave is provided through a double Brillouin scattering frequency shifting configuration.The use of the same laser source to generate the pump wave ensures the stability of the mm-wave generation system since the relative frequency shift between them can be eliminated.In addition, the mm-wave carrier obtains an RF power gain of 21 dB with the SBS amplification and a 3-dB bandwidth of 10kHz.展开更多
We theoretically investigate the optical second-order sideband generation(OSSG)in an optical parity-time(PT)symmetric system,which consists of a passive cavity trapping the atomic ensemble and an active cavity.Compare...We theoretically investigate the optical second-order sideband generation(OSSG)in an optical parity-time(PT)symmetric system,which consists of a passive cavity trapping the atomic ensemble and an active cavity.Compared with the double-passive system,it is found that near the exceptional point(EP),the efficiency of the OSSG increases sharply not only for the blue probepump detuning resonant case but also for the red one.Using experimentally achievable parameters,we study the effect of the atomic ensemble on the efficiency of the OSSG in the PT-symmetric system.The numerical results show that the efficiency of the OSSG is 30%higher than that of the first-order sideband,which is realized easily by simultaneously modulating the atom-cavity coupling strength and detuning.Moreover,the efficiency of the OSSG can also be tuned effectively by the pump power,and the efficiency is robust when the pump power is strong enough.This study may have some guidance for modulating the nonlinear optical properties and controlling light propagation,which may stimulate further applications in optical communications.展开更多
We propose and demonstrate an integrated microwave photonic sideband selector based on the thin-film lithium niobate(TFLN)platform by integrating an electro-optic Mach-Zehnder modulator(MZM)and a thermo-optic tunable ...We propose and demonstrate an integrated microwave photonic sideband selector based on the thin-film lithium niobate(TFLN)platform by integrating an electro-optic Mach-Zehnder modulator(MZM)and a thermo-optic tunable flat-top microring filter.The sideband selector has two functions:electro-optic modulation of wideband RF signal and sideband selection.The microwave photonic sideband selector supports processing RF signals up to 40 GHz,with undesired sidebands effectively suppressed by more than 25 d B.The demonstrated device shows great potential for TFLN integrated technology in microwave photonic applications,such as mixing and frequency measurement.展开更多
Parametric interaction allows both forward and backward energy transfers among the three interacting waves.The back-conversion effect is usually detrimental when unidirectional energy transfer is desired.In this theor...Parametric interaction allows both forward and backward energy transfers among the three interacting waves.The back-conversion effect is usually detrimental when unidirectional energy transfer is desired.In this theoretical work,we manifest that the back-conversion effect underpins the direct generation of the picosecond pulse train without the need for a laser resonator.The research scenario is an optical parametric amplification(OPA)that consists of a second-order nonlinear medium,a quasi-continuous pump laser and a sinusoidal amplitude-modulated seed signal.The back-conversion of OPA can transfer the modulation peaks(valleys)of the incident signal into output valleys(peaks),which inherently induces spectral sidebands.The generation of each sideband is naturally accompanied with a phase shift of±π.In the regime of full-back-conversion,the amount and amplitude of the sidebands reach the maximum simultaneously,and their phase constitutes an arithmetic sequence,leading to the production of a picosecond pulse train.The generated picosecond pulse train can have an ultrahigh repetition rate of 40 GHz or higher,which may facilitate ultrafast applications with ultrahigh speed.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12174344 and 12175199)Foundation of Department of Science and Technology of Zhejiang Province(Grant No.2022R52047)。
文摘In this paper,we investigate the phenomena of electromagnetically induced transparency and the generation of second-order sideband in a Laguerre–Gaussian cavity optorotational system with a Kerr nonlinear medium.Using the perturbation method,we analyze the first-and second-order sideband generations in the output field from the system under the actions of a strong control field and a weak probe field.Numerical simulations show that the Kerr nonlinearity can lead to the occurrence of the asymmetric line shape in the transmission of the probe field.Comparing with traditional scheme for generating the second-order sideband,our spectral shape of the second-order sideband is amplified and becomes asymmetric,which has potential applications in precision measurement,high-sensitivity devices,and frequency conversion.
基金supported by the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0301702 and 2024ZD0302000)the Natural Science Foundation of of Jiangsu Province(Grant No.BK20232002)+2 种基金the National Natural Science Foundation of China(Grant Nos.U21A20436 and 12074179)the Natural Science Foundation of Shandong Province(Grant No.ZR2023LZH002)Nanjing University-China Mobile Communications Group Co.,Ltd.Joint Institute.
文摘Fabrication-friendly superconducting qubits continue to be a leading candidate for scalable quantum computing.Recent developments in tunable couplers have significantly advanced the progress toward practical quantum processors.However,high-performance quantum control,particularly two-qubit gates,depends on the delicate tuning of the coupler spectrum,as misalignment can lead to undesirable phenomena such as frequency crowding,which may cause errors including state leakage.Here,we propose an efficient method for characterizing the coupler spectrum through sideband drivings,obviating the need for additional components in current quantum processors.We demonstrate this technique experimentally by employing both continuous-wave and pulsed measurement protocols,successfully extracting the coupler spectrum.Furthermore,by utilizing the measured coupler spectrum,we calibrate the frequency dependence of the effective coupling strength between two qubits linked by the coupler.The proposed approach offers significant practical benefits,enabling the efficient characterization of the coupler spectrum in existing quantum architectures,thus paving the way for enhanced quantum control and scalability.
基金Project supported by the National Natural Science Foundation of China(Grant No.U20A2075).
文摘Sideband cooling is a key technique for improving the performance of optical atomic clocks by preparing cold atoms and single ions into the ground vibrational state.In this work,we demonstrate detailed experimental research on pulsed Raman sideband cooling in a 171 Yb optical lattice clock.A sequence comprised of interleaved 578 nm cooling pulses resonant on the 1st-order red sideband and 1388 nm repumping pulses is carried out to transfer atoms into the motional ground state.We successfully decrease the axial temperature of atoms in the lattice from 6.5μK to less than 0.8μK in the trap depth of 24μK,corresponding to an average axial motional quantum number<nz><0.03.Rabi oscillation spectroscopy is measured to evaluate the effect of sideband cooling on inhomogeneous excitation.The maximum excitation fraction is increased from 0.8 to 0.86,indicating an enhancement in the quantum coherence of the ensemble.Our work will contribute to improving the instability and uncertainty of Yb lattice clocks.
基金National Natural Science Foundation of China(Grant Nos.51175370,51675368)Application of Basic Research and Frontier Technology Research Key Projects of Tianjin,China(Grant No.13JCZDJC34300)National Basic Research Program of China(973 Program,Grant No.2013CB035402)
文摘Time?variant excitations in planetary gear trains can cause excessive noise and vibration and even damage the system on a permanent basis. This paper focuses on the elastic vibrations of a helical planetary ring gear subjected to mesh and planet?pass excitations. Motivated by the structure, excitation and deformation symmetries, this paper proposes dual?frequency superposition and modulation methods to capture the mesh and sideband vibrations. The transi?tion between ring gear tooth and planet is introduced to address the excitations and vibrations. The phasing e ect of ring gear tooth and planet on various deformations is formulated. The inherent connections between the two types of vibrations are identified. The vibrations share identical exciting rules and the wavenumber and modulating signal order both equal the linear combination of tooth and planet counts. The results cover in?plane bending and extensional, out?of?plane bending and torsional deformations. Main findings are verified by numerical calculation and comparisons with the open literature. The analytical expressions can be used to determine whether the sideband is caused by component fault or only by elastic vibration. The methods can be extended to other power?transmission systems because little restriction is imposed during the analysis.
基金Project supported by the Research Fund of Tonghua Normal University(Grant No.202017ND)。
文摘In the unresolved sideband regime,we propose a scheme for cooling mechanical resonator close to its ground state in a three-cavity optomechanical system,where the auxiliary cavities are indirectly connected with the mechanical resonator through standard optomechanical subsystem.The standard optomechanical subsystem is driven by a strong pump laser field.With the help of the auxiliary cavities,the heating process is suppressed and the cooling process of the mechanical resonator is enhanced.More importantly,the average phonon number is much less than 1 in a larger range.This means that the mechanical resonator can be cooled down to its ground state.All these interesting features will significantly promote the physical realization of quantum effects in multi-cavity optomechanical systems.
文摘The glasses of 59 5H 3BO 3 40XF n 0 5Eu 2O 3 (X=Ca, Mg, Y, Pb, n =2 or 3) were prepared. The measurement of phonon sideband was performed. The higher energy range of phonon sideband spectra was fitted by Gaussian function, and the electron phonon coupling constant was calculated. The decreasing order of electron phonon coupling constant is from CaF 2, YF 3, MgF 2 to PbF 2, and the phonon sideband spectra are coincide with Raman scattering spectra.
基金supported by the National Natural Science Foundation of China(Grant No.51275523)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20134307110009)+1 种基金the Graduate Innovative Research Fund of Hunan Province,China(Grant No.CX20158015)the Excellent Graduate Innovative Fund of National University of Defense Technology(NUDT)(Grant No.B150305)
文摘We develop a simple and practical scheme to apply sideband cooling to a cloud of rubidium atoms. A sample containing 4 × 10^（70） ^（87）Rb is trapped in a far red detuned optical lattice. Through optimizing the relevant parameters, i.e., laser detuning, magnetic field, polarization, and duration time, a temperature around 1.5 μK and phase space density close to 1/500 are achieved. Compared with polarization gradient cooling, the temperature decreases by around one order of magnitude. This technique could be used in high precision measurement such as atomic clocks and atom interferometer. It could also serve as a precooling means before evaporation cooling in a dipole trap, and may be a promising method of achieving quantum degeneracy with purely optical means.
基金Project supported by the National Natural Science Foundation of China (Grant No 60708008)the Project of Academic Leaders in Shanghai,China (Grant No 07XD14030)the Knowledge Innovation Program of the Chinese Academy of Sciences
文摘Sideband manipulation of population inversion in a three-level A atomic configuration is investigated theoretically. Compared with the case of a nearly monochromatic field, a population inversion between an excited state and a ground state has been found in a wide sideband intensity range by increasing the difference in frequency between three components. Furthermore, the population inversion can be controlled by the sum of the relative phases of the sideband components of the trichromatic pump field with respective to the phase of the central component. Changing the sum phase from 0 to π, the population inversion between the excited state and the ground state can increase within nearly half of the sideband intensity range. At the same time, the sideband intensity range that corresponds to the system exhibiting inversion ρ00 〉 ρ11 also becomes wider evidently.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11564034 and 21663026)the Natural Science Foundation of Gansu Province, China (Grant No. 20JR5RA509)+1 种基金the Fundamental Research Funds for the Central Universities of College of Electrical Engineering, Northwest Minzu University (Grant Nos. 31920210016, 31920190006, and 31920200006)the Scientific Research Project of Hunan Educational Department, China (Grant No. 19B206)。
文摘We theoretically investigated a second-order optomechanical-induced transparency(OMIT) process of a hybrid optomechanical system(COMS), which a Bose-Einstein condensate(BEC) in the presence of atom-atom interaction trapped inside a cavity with a moving end mirror. The advantage of this hybrid COMS over a bare COMS is that the frequency of the second mode is controlled by the s-wave scattering interaction. Based on the traditional linearization approximation, we derive analytical solutions for the output transmission intensity of the probe field and the dimensionless amplitude of the second-order sideband(SS). The numerical results show that the transmission intensity of the probe field and the dimensionless amplitude of the SS can be controlled by the s-wave scattering frequency. Furthermore, the control field intensities,the effective detuning, the effective coupling strength of the cavity field with the Bogoliubov mode are used to control the transmission intensity of the probe field and the dimensionless amplitude of the SS.
基金work was supported by the NSFC(Grant Nos.12522501 and 12247103)the Sci-entific Research Innovation Capability Support Project for Young Faculty(Grant No.SRICSPYF-BS2025131).
文摘study drifting modulation instability(MI)that exhibits asymmetric discrete spectrum recurrences in the nonlinear stage within the framework of the focusing nonlinear Schr¨odinger equation.We demonstrate that such drifting MI can arise either from the local periodization of general breathers or from numerical simulations starting with an initial modulation containing asymmetric sidebands.
基金supported by the Quantum Science and Technology-National Science and Technology Major Project(2024ZD0302403)the National Natural Science Foundation of China(12434015 and 62275145)+1 种基金the Fundamental Research Program of Shanxi Province(202403021224001)the Fund for Shanxi“331 Project”Key Subjects Construction.
文摘As an important quantum communication protocol,quantum teleportation has broad applications in quantum information science and technology.For the application,it is essential to enhance the ability of quantum teleportation by teleporting multiple quantum states simultaneously.Here,we experimentally demonstrate deterministic quantum teleportation of multiple sideband qumodes of coherent states,which corresponds to teleporting multiple quantum states simultaneously,with the assistance of continuous-variable(CV)quantum entanglement.By fine-tuning the phases of two classical channels according to different adjustable frequencies,we successfully realize deterministic CV quantum teleportation with up to 5 sideband qumodes simultaneously within the frequency bandwidth of 24 MHz.We show that the number of teleported multiple qumodes is controllable by changing the phases of two classical channels.The obtained fidelities of output multiple qumodes are around 70%,which are all beyond the non-cloning limit.The results present a novel method for quantum teleportation of multiple quantum states simultaneously and take a crucial step in enhancing the teleporting ability of quantum teleportation.
基金supported by the National Natural Science Foundation of China(Grant Nos.52205112,12121002)the China Postdoctoral Science Foundation(Grant No.2022M712063)。
文摘Gearboxes,known for their compact size and stable transmission capability,are widely used as power transmission structures in various types of mechanical equipment,such as wind turbines,helicopters,and special vehicles.However,due to harsh and non-stationary working conditions,gear surfaces often deteriorate,leading to faults such as wear,pitting,and cracking.Therefore,it is vital to monitor the working status of gearboxes and diagnose gear faults as early as possible.Gear faults can induce characteristic modulation effects near the gear meshing frequency(GMF),resulting in the appearance of faultinduced sidebands in a vibration spectrum.Extraction of these sidebands allows for the diagnosis of gear faults in a gearbox.However,when faced with a planetary gearbox having a complex configuration,strong background noise and additional faultunrelated sidebands can interfere with fault-induced sidebands,making accurate diagnosis difficult.To address these challenging issues,this paper proposes a novel fault-induced gear meshing modulation sideband extraction method.In the process,the sidebands directly related to the gear fault near the GMF are first identified and then extracted by a variational harmonic mode decomposition(VHMD)method.Accordingly,a fault-related gear meshing modulation component(GMMC)can be accurately reconstructed by summing up the extracted fault-induced sidebands.Using the GMMC,the gear fault severity can be assessed by evaluating its amplitude modulation(AM)effect.The superior performance of the proposed method is finally demonstrated by experimental data.
基金supported by the National Natural Science Foundation of China(Grant Nos.62225504,62027821,U22A6003,12304399,12174234,12274275,and 62375162)the Fundamental Research Program of Shanxi Province(Grant Nos.202303021212003,and 202303021224006).
文摘Constructing large-scale quantum resources is an important foundation for further improving the efficiency and scalability of quantum communication.Here,we present an efficient extraction and stable control scheme of 40 pairs of entangled sideband modes from the squeezed light by specially designing an optical parametric oscillator.Utilizing the low-loss optical frequency comb control technology and the local cross-correlation algorithm,we model and manage the efficient separation process of the entangled sideband modes facilitated by the optical filtering cavities,and a maximum entanglement level of 6.5 dB is achieved.The feasibility of large-capacity quantum dense coding based on these entangled sideband modes is proved experimentally,which is of great significance for optimizing the utilization of quantum resources,thereby contributing to the advancement of largecapacity quantum communication networks and enabling the realization of more secure and efficient quantum communication systems.
基金supported by the National Research Foundation of Korea(NRF)grant(RS-2022-NR072112)the National Research Council of Science&Technology(NST)grant(No.CAP21034-000)+1 种基金Institute for Information&Communications Technology Planning&Evaluation(IITP)grant(No.RS-2025-02219093)the Korea Research Institute of Standards and Science(GP2025-0010-03)funded by the Korea government(MSIT).
文摘Superconducting optomechanical circuits enable frequency mixing of optical and mechanical modes,facilitating the generation of microwave frequency combs.However,such optomechanical combs suffer from frequency fluctuations,requiring their stabilization for applications in precision sensing and signal processing.Here,we investigate the sideband injection locking of microwave frequency combs in a niobium-based superconducting optomechanical circuit.By strongly driving the device with a blue-detuned pump to induce parametric instability and introducing an additional tone near individual comb peaks,we study how the locking range varies with the power,the frequency position,and the sweep direction of the injection tone.The locking responses show interesting features such as injection hysteresis,which cannot be explained by existing models.Numerical simulations of the classical optomechanical equations implementing a cubic mechanical nonlinearity show that the nonlinearity contributes to broadening the locking range.We also characterize the Allan deviations and phase noise of the injection-locked combs for different injection frequencies,demonstrating enhanced stability performance.Our results lay the foundation for the utilization of optomechanical combs for applications in nanomechanical sensing and cryogenic microwave pulse generation.
文摘Polarization fluctuation induced noise and backscattering-induced noise are the dominant noises in resonant fiber optic gyroscopes. This Letter proposes a new method to suppress the carrier and backscattering induced noise by the sideband locking technique. Besides choosing an optimized modulation depth and different clockwise and counterclockwise modulation frequencies, the sideband is locked to the cavity resonance. With the proper modulation frequency, the carrier frequency component locates at a position far away from the resonant frequency, and then it is suppressed by the cavity itself, which can be taken as a bandpass filter. The amplitude of the carrier frequency can be suppressed by 20–25 d B additionally by the cavity and the total intensity suppression ratio can reach 115.74 d B. The backscattering induced noise can be eliminated for the adoption of different frequencies. The method can realize a stable and high suppression ratio without high requirements for parameter accuracy or device performance.
基金Project supported by the Meteorology Industry Research Project of China(Nos.GYHY200806033,GYHY201006045)the National Natural Science Foundation of China(Nos.61021003,61090391,60837001,60820106004)+1 种基金the National Basic Research Program of China (No.2009AA03Z409)the Open Fund of Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications),Ministry of Education
文摘A new technique to generate a millimeter（mm）-wave carrier of 32.57 GHz（f_（LO）=10.85 GHz） with single sideband modulation（SSB） for radio-over-fiber（RoF） systems is experimentally demonstrated by using stimulated Brillouin scattering（SBS）.The SSB is realized by directly amplifying the ＋3rd sideband of the modulated optical carrier in the process of SBS.The pump wave is provided through a double Brillouin scattering frequency shifting configuration.The use of the same laser source to generate the pump wave ensures the stability of the mm-wave generation system since the relative frequency shift between them can be eliminated.In addition, the mm-wave carrier obtains an RF power gain of 21 dB with the SBS amplification and a 3-dB bandwidth of 10kHz.
基金supported by the National Natural Science Foundation of China(Grant Nos.61368002,91736106,11674390,and 91836302)the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(Grant No.KF201711)+1 种基金the Foundation for Distinguished Young Scientists of Jiangxi Province(Grant No.20162BCB23009)the Graduate Innovation Special Fund of Jiangxi Province(Grant No.YC2019-S102)。
文摘We theoretically investigate the optical second-order sideband generation(OSSG)in an optical parity-time(PT)symmetric system,which consists of a passive cavity trapping the atomic ensemble and an active cavity.Compared with the double-passive system,it is found that near the exceptional point(EP),the efficiency of the OSSG increases sharply not only for the blue probepump detuning resonant case but also for the red one.Using experimentally achievable parameters,we study the effect of the atomic ensemble on the efficiency of the OSSG in the PT-symmetric system.The numerical results show that the efficiency of the OSSG is 30%higher than that of the first-order sideband,which is realized easily by simultaneously modulating the atom-cavity coupling strength and detuning.Moreover,the efficiency of the OSSG can also be tuned effectively by the pump power,and the efficiency is robust when the pump power is strong enough.This study may have some guidance for modulating the nonlinear optical properties and controlling light propagation,which may stimulate further applications in optical communications.
基金supported by the National Key Research and Development Program of China(No.2021YFB2800104)the National Natural Science Foundation of China(Nos.62175079 and 62205119)。
文摘We propose and demonstrate an integrated microwave photonic sideband selector based on the thin-film lithium niobate(TFLN)platform by integrating an electro-optic Mach-Zehnder modulator(MZM)and a thermo-optic tunable flat-top microring filter.The sideband selector has two functions:electro-optic modulation of wideband RF signal and sideband selection.The microwave photonic sideband selector supports processing RF signals up to 40 GHz,with undesired sidebands effectively suppressed by more than 25 d B.The demonstrated device shows great potential for TFLN integrated technology in microwave photonic applications,such as mixing and frequency measurement.
基金This work was supported by the National Natural Science Foundation of China(Nos.61727820,61905142,61975120,and 91850203).
文摘Parametric interaction allows both forward and backward energy transfers among the three interacting waves.The back-conversion effect is usually detrimental when unidirectional energy transfer is desired.In this theoretical work,we manifest that the back-conversion effect underpins the direct generation of the picosecond pulse train without the need for a laser resonator.The research scenario is an optical parametric amplification(OPA)that consists of a second-order nonlinear medium,a quasi-continuous pump laser and a sinusoidal amplitude-modulated seed signal.The back-conversion of OPA can transfer the modulation peaks(valleys)of the incident signal into output valleys(peaks),which inherently induces spectral sidebands.The generation of each sideband is naturally accompanied with a phase shift of±π.In the regime of full-back-conversion,the amount and amplitude of the sidebands reach the maximum simultaneously,and their phase constitutes an arithmetic sequence,leading to the production of a picosecond pulse train.The generated picosecond pulse train can have an ultrahigh repetition rate of 40 GHz or higher,which may facilitate ultrafast applications with ultrahigh speed.
