A5025928162- Atomic and Subatomic Physics Research
- Dark Matter and Cosmic Phenomena
- Quantum optics and atomic interactions
- Magnetic Field Sensors Techniques
- Advanced MRI Techniques and Applications
- Quantum, superfluid, helium dynamics
- Sensor Technology and Measurement Systems
- Diamond and Carbon-based Materials Research
- Mechanical and Optical Resonators
- Astrophysics and Cosmic Phenomena
- Ionosphere and magnetosphere dynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Magneto-Optical Properties and Applications
- Non-Destructive Testing Techniques
- Magnetic properties of thin films
- Advanced Fiber Laser Technologies
- Magnetic Properties and Synthesis of Ferrites
- Cavitation Phenomena in Pumps
- Geophysics and Sensor Technology
- Metallic Glasses and Amorphous Alloys
- Heat Transfer Mechanisms
- High-Temperature Coating Behaviors
- Cyclone Separators and Fluid Dynamics
- Scientific Measurement and Uncertainty Evaluation
- Fluid Dynamics and Thin Films
Agency for Science, Technology and Research
2025
Princeton University
2020-2025
Institute of Materials Research and Engineering
2025
Beihang University
2012-2024
A*STAR Graduate Academy
2024
Xihua University
2024
University of California, Berkeley
2017-2019
Institute of Engineering Thermophysics
2019
Chinese Academy of Sciences
2019
University of Chinese Academy of Sciences
2019
We report the results of an experimental search for ultralight axion-like dark matter in mass range 162 neV to 166 neV. The detection scheme our Cosmic Axion Spin Precession Experiment (CASPEr) is based on a precision measurement $^{207}$Pb solid-state nuclear magnetic resonance polarized ferroelectric crystal. Axion-like can exert oscillating torque spins via electric-dipole moment coupling $g_d$, or gradient $g_{\text{aNN}}$. calibrated detector and characterized excitation spectrum...
Abstract Ultralight bosons such as axion-like particles are viable candidates for dark matter. They can form stable, macroscopic field configurations in the of topological defects that could concentrate matter density into many distinct, compact spatial regions small compared with Galaxy but much larger than Earth. Here we report results search transient signals from domain walls by using global network optical magnetometers exotic (GNOME) physics searches. We data, consisting correlated...
A novel method to compensate the residual magnetic field for an atomic magnetometer consisting of two perpendicular beams polarizations was demonstrated in this paper. The can realize compensation case where pumping rate probe beam cannot be ignored. In experiment, is always linearly polarized, whereas, contains a circular component due imperfection polarizer, which leads effect beam. simulation beam's optical rotation and demonstrated. At optimized points, wavelength achieve largest...
The cosmic axion spin precession experiment (CASPEr) is a nuclear magnetic resonance (NMR) seeking to detect and axion-like particles which could make up the dark matter present in Universe. We review predicted couplings of axions with baryonic that enable their detection via NMR. then describe two measurement schemes being implemented CASPEr. first method, presented original CASPEr proposal, consists resonant search continuous-wave NMR spectroscopy. This method offers highest sensitivity...
Abstract We introduce a vector atomic magnetometer that employs fast-rotating magnetic field applied to pulsed 87 Rb scalar magnetometer. This approach enables simultaneous measurements of the total and its two polar angles relative rotation plane. Operating in gradiometer mode, achieves gradient sensitivity 35 $${{{\rm{fT}}}}/\sqrt{{{{\rm{Hz}}}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>fT</mml:mi> <mml:mo>/</mml:mo> <mml:msqrt> <mml:mrow> <mml:mi>Hz</mml:mi>...
According to recent predictions, a microscale ferromagnetic needle will precess under the influence of small applied torque, if sufficiently isolated from environment. In fact, such system could be used measure torques with sensitivity far surpassing standard quantum limit for free ensemble spins. To observe precession and carry out ultrasensitive torque measurements, requires nearly frictionless suspension. Here crucial initial steps are realized by levitating micrometer-scale particle...
An experimental test at the intersection of quantum physics and general relativity is proposed: measurement relativistic frame dragging geodetic precession using intrinsic spin electrons. The behavior in spacetime dragged warped by a massive rotating body an experimentally open question, hence results such could have important theoretical consequences. Such possible mm-scale ferromagnetic gyroscopes orbit around Earth. Under conditions where rotational angular momentum ferromagnet...
The hybrid optical pumping atomic magnetometers have not realized its theoretical sensitivity, the optimization is critical for optimal performance. optimizations proposed in this paper are suitable magnetometer, which contains two alkali species. To optimize parameters, dynamic equations of spin evolution with species were solved, whose steady-state solution used to parameters. demand power pump beam large pumping. Moreover, sensitivity magnetometer increases increase density beam. ratio...
A ferromagnetic gyroscope (FG) is a ferromagnet whose angular momentum dominated by electron spin polarization and that will precess under the action of an external torque, such as due to magnetic field. Here we model analyze FG dynamics sensitivity, focusing on practical schemes for experimental realization. In case freely floating FG, transition from libration in relatively high externally applied fields, those precession at low fields. Measurement frequency enables situ measurement field...
This paper presents an approach to detect the presence of Dynabeads with a system based on micro fluxgate sensor fabricated by micro-electro-mechanical systems technology. Due excellent performance sensor, detection exhibited many advantages, such as lower minimum detectable limit, small weight, and low power consumption. Experimental results show that, applied external magnetic field in range 430 μT 600 μT, concentration 0.1 μg/ml can be detected this system. Moreover, could give...
Levitated ferromagnets act as ultraprecise magnetometers, which can exhibit high quality factors due to their excellent isolation from the environment. These instruments be utilized in searches for ultralight dark matter candidates, such axionlike or dark-photon matter. In addition being sensitive an axion-photon coupling kinetic mixing, produce physical magnetic fields, are also effective field (or “axion wind”) produced by axion-electron coupling. While dynamics of a levitated ferromagnet...
In this paper, based on the multiwire core design and microelectromechanical system technology, we report improved performance of a microsolenoid fluxgate sensor by integrating bilayer co-based amorphous ribbon. By means utilizing integrated multilayer structure high permeability ribbon material, paper shows how high-performance microfluxgate chip with small dimensions can be realized. The fabricated sensors exhibit best sensitivity 3165 V/T, power 183.2 mW linear range 150 μT at 100 kHz....
A method of measuring in-situ magnetic field gradient is proposed in this paper. The shield widely used the atomic magnetometer. However, there shield, which would lead to additional broadening. It impossible use an ex-situ magnetometer measure region a cell, whose length side several centimeters. demonstrated paper can realize measurement inside significant for spin relaxation study. gradients along longitudinal axis are measured by spin-exchange relaxation-free (SERF) adding modulation...
We investigated the operation of an all-optical rubidium-87 atomic magnetometer with amplitude-modulated light. To study suppression spin-exchange relaxation, three schemes pumping were implemented room-temperature and heated paraffin coated vacuum cells. Efficient accumulation atoms in F=2 ground state obtained. However, sought-for narrowing resonance lines has not been achieved. A theoretical analysis polarization degree is presented to illustrate absence light due radiation trapping at...
The micro fluxgate sensors have shown high sensitivity for the magnetic beads detection. For portable biological detection, Co-based amorphous ribbons with permeability and low saturation induction are chosen as core materials to lower operation requirements of fluxgate-based single-layer bi-layer fabricated by Micro-Electro-Mechanical System technologies, which exhibit a power consumption 10.88 mW 24.48 mW, 1644 V/T 1456 V/T, noise 1.66 nT/Hz1/2@1 Hz 2.32 Hz, respectively. Dynabeads...
We present a technique employing dielectrophoretic (DEP) manipulation of surface immobilized complexes integrated with magnetic imaging platform based on nitrogen-vacancy (NV) centers in diamond for the quantitative measurements non-covalent interactions. The interdigitated microelectrodes closely spaced to functionalized plate provide wide range applied DEP forces noninvasive various molecular interactions, while NV layer under reports unbinding dynamics. Given that biological samples do...
In this paper, a microfluxgate sensor was introduced into the application of magnetic bead detection. Micro-electro-mechanical systems (MEMS) technology used to realize sensor. Making use superparamagnetic property that micron-sized beads can be magnetized in field, detection system based on designed and established. Dynabeads obtained by purchase were diluted different concentrations characterize performance system. Experimental results show applying dc field range 0.54 1.05 mT, with...
Atomic magnetometers use the coherent precession of polarized atomic spins to detect and measure magnetic fields. When an off-resonant, linearly probe beam propagates through vapor cell, will cause a rotation its polarization plane. Measuring angle rotation, field can be calculated. In this paper, we introduce basic principles describe method angle. Then dual-phase lock-in amplifier (LIA) is proposed weak signal magnetometer. And design simulation for LIA based on Matlab/Simulink. Our...
This study investigates the performance and internal flow characteristics of a single-blade centrifugal pump through comprehensive analysis integrating tests, Particle Image Velocimetry (PIV) numerical simulations. Across operational speed range 1470–2940 rpm, predicted (head-flow rate curve)performance error between simulation results test underrated conditions is found to be only 3.4%, demonstrating high accuracy selected method in predicting both metrics structures. Key findings highlight...
Frequency stabilization for external cavity diode laser has played an important role in physics research. Many frequency locking solutions have been proposed by researchers. Traditionally, the process was accomplished analog system, which fast feedback control response speed. However, system is susceptible to effects of environment. In order improve automation level and reliability we take a grating-feedback as source set up digital based on National Instrument's FPGA (NI FPGA). The consists...