A5073503404- Advanced Frequency and Time Standards
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Quantum optics and atomic interactions
- Advanced Fiber Laser Technologies
- Scientific Measurement and Uncertainty Evaluation
- Advanced MRI Techniques and Applications
- Spectroscopy and Laser Applications
- Industrial Technology and Control Systems
- Laser Design and Applications
- Advanced Algorithms and Applications
- Advanced Sensor and Control Systems
- Antenna Design and Analysis
- Atomic and Molecular Physics
- Chaos-based Image/Signal Encryption
- Analytical Chemistry and Sensors
- Advanced Steganography and Watermarking Techniques
- Machine Learning and ELM
- Geophysics and Sensor Technology
- Quantum Information and Cryptography
- Rough Sets and Fuzzy Logic
- Aerodynamics and Fluid Dynamics Research
- Visual Attention and Saliency Detection
- Gait Recognition and Analysis
- Optical and Acousto-Optic Technologies
China National Petroleum Corporation (China)
2025
Huazhong University of Science and Technology
2013-2024
Guizhou Institute of Technology
2024
Shenzhen University
2024
Xi’an Jiaotong-Liverpool University
2024
Guangxi University of Science and Technology
2007-2019
University of British Columbia
2015
Peking University
2005-2011
Sichuan University
2005-2009
Optical clocks have been demonstrated to be good choices redefine the SI ``second.'' With this goal, we constructed a quantum-logic-based ${}^{27}$$\mathrm{Al}$${}^{+}$ ion optical clock with fractional frequency uncertainty of $1.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}18}$. A ${}^{25}$$\mathrm{Mg}$${}^{+}$ is used as logic for sympathetic cooling, state readout, and frequency-shift measurement ion. The stability...
Gas drilling technology remains a superior method for discovering and protecting oil gas reservoirs in the petroleum exploration development industry. However, its widespread application further advancement have been significantly hindered by safety risks associated with surface equipment. Owing to constraints of mountainous terrain, connection blooie line inevitably adopts multiple elbow connections. As result, aerodynamic flutter will occur when high-speed flow enters line, which threatens...
Constrained optimization demands highly efficient solvers which promotes the development of learn-to-optimize (L2O) approaches. As a data-driven method, L2O leverages neural networks to efficiently produce approximate solutions. However, significant challenge remains in ensuring both optimality and feasibility networks' output. To tackle this issue, we introduce Homeomorphic Polar Learning (HoP) solve star-convex hard-constrained by embedding homeomorphic mapping networks. The bijective...
Abstract Many space based gravity missions require frequency stabilized lasers with stringent requirements. Toward those requirements, we develop a compact frequency-stabilized laser which is referenced to the R(56)32−0: 1 transition of molecular iodine on modulation transfer spectroscopy technique. The stability limited by beam pointing noise, electronic servo and residual amplitude (RAM) noise. To improve stability, system constructed gluing most components optical an ultra-low expansion...
Efficient cooling of trapped ions is a prerequisite for various applications the in precision spectroscopy, quantum information, and coherence control. Raman sideband an effective method to cool their motional ground state. We investigate both numerically experimentally optimization strategies propose efficient one, which can simplify experimental setup as well reduce number pulses. Several schemes are tested compared through numerical simulations. The simulation result shows that...
We report on the development and performance evaluation of an ultra-stable laser for 27Al+ optical clock. After a series noise suppressions, especially vibrational temperature fluctuation noise, 30 cm long cavity stabilized obtains frequency instability 1.3 × 10−16 @1 s. This result is predicted by summation confirmed three-cornered hat method. The clock transition also used to characterize consistent results are yielded. first reported instance using single ion clocks measure lasers, as far...
We studied the relationship between pressure ratio of buffer gases (argon and neon) rate coherent population trapping resonance frequency shift with cell temperature in Rb85. found that when total varies within range 5–15kPa, along a bell shaped curve. Every curve crossed horizontal axis at two points are roughly symmetrical respect to midpoint 1:1. This allows us minimize by adjusting these points.
A high-frequency signal generator based on direct digital synthesizer (DDS) and field-programmable gate array (FPGA) is presented. The FPGA provides the controlling time sequence for DDS, which has a highest output frequency of 1.4 GHz resolution 190 pHz. At an 1.2 GHz, measured phase noise, including contribution reference clock, −65 dBc/Hz@1 Hz, while intrinsic noise −82 Hz. Time delay DDS to be less than 150 ns. used drive acousto-optic modulator, rise due whole link 24 developed can in...
We proposed a scheme to implement coherent population trapping (CPT) atomic clock based on the transient CPT phenomenon. proved that transmitted laser power in typical Λ system near resonance features as damping oscillation. Also, oscillating frequency is exactly equal detuning from hyperfine splitting. Therefore, we can directly measure and then compensated output of microwave oscillator get standard frequency. By this method, further simplify structure clock, make it easier be digitized...
We demonstrate thermal noise limited and shot performance of ultra-stable diode laser systems. The measured heterodyne beat linewidth between such two independent lasers reaches 0.74 Hz. frequency instability one single approaches 1.0 × 10−15 for averaging time 0.3 s 10 s, which is close to the limit reference cavity. Taking advantage these systems, we systematically investigate ultimate electrical contributions, derive expressions closed-loop spectral density noise. power compared with...
As many precision laser spectroscopy experiments require frequency stabilized lasers, development of long-term lasers is great interest. In this work, we report stabilization a 280 nm deep ultraviolet to high wavemeter with digital servo control such that the drift was greatly reduced. Long-term measured fiber comb system over 8 h. After locking, maximum rate lowered from 576 MHz/h 6.4 MHz/h. With proper environment wavemeter, further less than 480 kHz/h. The locked successfully used in Mg+...
High voltage radio frequency (RF) supply is a critical part in an ion trapping system. The RF should have high Q-factor and relatively driving frequency. A frequently used for trap system helical resonator. In certain applications, it advantageous to predictable resonant when the resonator connected capacitive load. We develop model describe behavior of with With this model, we can correctly predict loaded Q-factor. To test our prediction, construct resonator, measure its frequencies...
Higher-order mode locking has been proposed to reduce the thermal noise limit of reference cavities. By a laser HG02 10-cm long all ultra-low expansion (ULE) cavity and measuring its performance with three-cornered-hat method among three independently stabilized lasers, we demonstrate thermal-noise-limited fractional frequency instability 4.9×10-16. The results match theoretical models higher-order optical modes. achieved improves ULE short new low level.
In order to achieve high frequency stability in ultra-stable lasers, the Fabry-Pérot reference cavities shall be put inside vacuum chambers with large thermal time constants reduce sensitivity external temperature fluctuations. Currently, determination of is based either on theoretical calculation or time-consuming experiments. The first method can only apply simple system, while second will take a lot try out different designs. To overcome these limitations, we present constant simulation...
Al$^+$ ions optical clock is a very promising frequency standard candidate due to its extremely small blackbody radiation shift. It has been successfully demonstrated with indirect cooled, quantum-logic-based spectroscopy technique. Its accuracy limited by second-order Doppler shift, and stability the number of that can be probed in quantum logic processing. We propose direct laser cooling scheme clocks where both are greatly improved. In proposed scheme, two traps utilized. The first trap...
Abstract Magnetic field noise is an important factor causing quantum decoherence in systems. In order to suppress the effect, magnetic needs be properly measured and controlled. power spectrum measurement using a single trapped ion based analyzer very effective way. this paper, on dynamic decoupling technique analyzed theoretically. Furthermore, we use magnetically insensitive transition measure noise, which has potential stronger speed up process. our experiment, by active feedback control...
We report an experimental determination of the ground-state hyperfine constant $A$ $^{25}\mathrm{Mg}^{+}$ ions by measuring $|{S}_{1/2},F=2,m=0\ensuremath{\rangle}$ to $|{S}_{1/2},F=3,m=0\ensuremath{\rangle}$ transition (0-0 transition) frequency two energy levels. The is measured rf resonant method in a Paul trap under magnetic field about 0.1 mT. result $A=\ensuremath{-}596.254$ 248 7(42) MHz. Different shifts and uncertainties are evaluated. main effect quadratic Zeeman shift. Since...
We present a novel method to phase lock two lasers with controllable frequency difference. A microwave frequency-modulated vertical-cavity surface-emitting laser is used connect diode by two-step injection locking. The fluctuations of the are measured be 6.4 x 10(-4) rad2, corresponding 99.94% coherence. difference tunable up tens gigahertz. sideband suppression slave more than 30 dB at microW seed power. narrow linewidth spectrum coherent population trapping in rubidium achieved using such beams.
RF quadrupole linear Paul traps are versatile tools in quantum physics experiments. Linear with blade-shaped electrodes have the advantages of larger solid angles for fluorescence collection. But these kinds traps, existence higher-order anharmonic terms trap potentials can cause large heating rate trapped ions. In this paper, we theoretically investigate dependence on geometry and offer an optimized design. A modified blade is proposed to further reduce while still retaining collection angle.
An aluminium ion optical clock is under development at Huazhong University of Science and Technology. The 25Mg+ chosen as logic to sympathetically cool an Al+ detect its states. cooled the motional ground state through Raman sideband cooling first step for quantum spectroscopy. Ultra-stable lasers interrogation transition are developed. instability laser beat frequency 1.2 x 10-15 1 s, which close thermal noise limit reference cavity.