Review of Scientific Instruments

Mapping the magnetic field vector in a fountain clock

Marina Gertsvolf, L. Marmet

Published Dec 1, 2011• 3 citations

Abstract

We show how the mapping of the magnetic field vector components can be achieved in a fountain clock by measuring the Larmor transition frequency in atoms that are used as a spatial probe. We control two vector components of the magnetic field and apply audio frequency magnetic pulses to localize and measure the field vector through Zeeman spectroscopy.

DOI: 10.1063/1.3671633

Related papers

Magnetic field measurement by stimulated Raman transitions and smoothing by dynamical compensation in rubidium fountain clock

Wenli Wang, Richang Dong, Rong Wei +3 more

We present a method for magnetic field measurement by the weak magnetic-sensitive Zeeman splitting and a method for measuring the magnetic field vector by probing the line strength of stimulated Raman transitions. Compared with the traditional measurement, the contrast of the weak magnetic-sensitive resonance signal is improved significantly for gradient field. We also present a dynamical compensation method to smooth the spatial fluctuation of the magnetic field in the fountain clock. A homogeneous field with a 0.4 nT peak-to-peak value is realized compared to 5nT under the static magnetic field.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)Jul 1, 20170 citations

Measurement of a Weak Magnetic Field Using Cold Atoms

Takayuki Kurosu, Yasuhiro Fukuyama, Kentaro Abe +1 more

Laser-cooled atoms were utilized to precisely measure a weak magnetic field. The technique is based on the linear Zeeman shift of the hyperfine transition of cesium atom and allows high-resolution measurement in the presence of a field gradient. The method was applied to evaluate the C-field of an atomic fountain frequency standard, in which a field-sensitive transition was probed by Ramsey resonance. The relationship between the measurement time and the resolution is also discussed.

Japanese Journal of Applied PhysicsMay 15, 20024 citations

87Rb喷泉原子钟的磁场测量

Chunyan Shi, Rong Wei, Zichao Zhou +3 more

An experiment on measuring the magnetic field in Ramsey interaction region of the atomic fountain clock by detecting the Zeeman frequency shift of 87 Rb hyperfine transition is presented.By mu-metal shielding and coils compensating, the magnetic fluctuations resulting from asymmetry and instability are less than 10 and 0.025 nT, respectively.The relative frequency uncertainty of atomic fountain clock caused by the magnetic field is less than 5.4×10 -16 .

Chinese Optics LettersJan 1, 201017 citations

Uncertainty evaluation of the second-order Zeeman shift of a transportable 87Rb atomic fountain clock

He-Nan Cheng, Siminda Deng, Zhen Zhang +7 more

In this article, taking advantage of the special magnetic shieldings and the optimal coil design of a transportable Rb atomic fountain clock, the intensity distribution in space and the fluctuations with time of the quantization magnetic field in the Ramsey region were measured using the atomic magneton-sensitive transition method. In an approximately 310 mm long Ramsey region, a peak-to-peak magnetic field intensity of a 0.74 nT deviation in space and a 0.06 nT fluctuation with time were obtained. These results correspond to a second-order Zeeman frequency shift of approximately (2095.5±5.1)×10-17. This is an essential step in advancing the total frequency uncertainty of the fountain clock to the order of 10-17.

Chinese Optics LettersJan 1, 20217 citations

Vector measurements using all optical scalar atomic magnetometers

Rui Zhang, Rahul Mhaskar, Ken Smith +2 more

Vector field measurement is demonstrated with an all-optical scalar atomic magnetometer using intrinsic parameters related to its scalar operation. The Bell-Bloom type atomic magnetometer measures the Larmor precession of cesium atoms through on-resonant absorption of a probe beam. While the AC component of the probe signal is used for the field magnitude measurement, the probe DC signal contains information about the polar angle, defined as the angle between the magnetic field and the probe beam. Additional polar angle information is obtained from the light-shift-induced magnetic field caused by the frequency modulation of the probe beam. With a measurement time of 100 ms, better than 0.02° sensitivity has been achieved using a commercial miniaturized sensor at the optimal sensor orientation. The angle measurement accuracy is checked against an optical encoder over the entire polar angle range of 0°–180°. Better than 1° error is recorded over most set polar angles. Azimuthal angle measurement is also exhibited with two orthogonally oriented sensors.

arXiv:2011.08943Journal of Applied PhysicsJan 28, 202117 citations

Measurement of magnetic field stability using 40Ca+ ion

Pham, Minh Tuan

One of the main limitations in the long-term measurement of the clock transition's absolute frequency is the magnetic field's fluctuation. The time-varying fluctuation of the external magnetic field leads to frequency shifts of the Zeeman components, thereby reducing the optical clock's frequency stability over time. Currently, optical atomic references are usually implemented with the help of a single ion. However, scaling the number of ions to higher values brings an indisputable benefit in the form of a high signal-to-noise ratio and, thus to the efficiency of the entire measurement process. In this case, the ions are spread over a large area, forming so-called ionic Coulomb crystals. In addition to the spatial stability of the magnetic field, the homogeneity of the magnetic field is also significant when working with Coulomb crystals. Excessive magnetic perturbation can be greatly reduced by covering the assembly with a magnetic shield or by using permanent magnets instead of conventionally used magnetic coils. Another method is averaging over multiple-level transitions. This contribution presents a simple method for measuring the stability of the magnetic field at the ion position.

Jan 1, 20220 citations