Bulletin of the American Physical Society
47th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 61, Number 8
Monday–Friday, May 23–27, 2016; Providence, Rhode Island
Session T6: Atomic Magnetometers II |
Hide Abstracts |
Chair: Thad Walker, University of Wisconsin-Madison Room: 552AB |
Friday, May 27, 2016 8:00AM - 8:12AM |
T6.00001: Synchronous Spin Exchange Optical Pumping for Precision NMR Anna Korver, Josh Weber, Daniel Thrasher, Thad Walker We present the successful execution of synchronous spin exchange optical pumping for precision NMR. In this novel form of NMR, the bias field is applied as a sequence of alkali $2 \pi$ pulses; the resulting transverse alkali polarization is then modulated at the NMR frequency and spin exchange collisions build up a transverse precessing noble gas polarization. As compared to longitudinally pumped NMR, this method suppresses the alkali frequency shift by over a factor of 2500. We also discuss how we use synchronous spin exchange optical pumping to excite two noble gas species simultaneously. With dual species operation, we are able to use one species to lock the magnetic field while the other is left to detect nonmagnetic interactions. This method promises to achieve NMR frequency uncertainties of 100nHz/$\sqrt{\mathrm{Hz}}$. Research supported by the NSF and Northrop-Grumman Corp. [Preview Abstract] |
Friday, May 27, 2016 8:12AM - 8:24AM |
T6.00002: A new miniaturized atomic~magnetic~gradiometer Dong Sheng, Abigail Perry, Sean Krzyzewski, Shawn Geller, Svenja Knappe, John Kitching We report the development of a new miniaturized magnetic gradiometer using alkali atoms. The gradiometer, with the length of~5 cm and cross section diameter of~11 mm,~is made of two chip-scale atomic magnetometers placed on a printed optical bench with a defined separation. Both magnetometers work in the spin-exchange relaxation free regime, share the same beam for pumping and probing to reduce the common mode noises from the lasers, and atom temperature is independently controlled by heating beams at telecom wavelength.~ With 2 cm baseline,~1 mW pumping beam power, and less than 400 mW input heating beam power, we measure a noise level of 15 fT/Hz$^{\mathrm{1/2}}$ from the subtraction of two magnetometer outputs, which corresponds to a gradient field sensitivity of 7.5 fT/Hz$^{\mathrm{1/2}}$/cm. The maximum common mode magnetic field noise rejection is up to 1000 within the gradiometer bandwidth. This device is useful in many fields that require both~sensitive~gradient field information and high~common mode noise cancellation. We are also developing a new hybrid system based on this device to improve its dynamical range. [Preview Abstract] |
Friday, May 27, 2016 8:24AM - 8:36AM |
T6.00003: Pulsed 3-Axis Vector SERF Magnetometer Morgan Hedges, Michael Romalis We demonstrate a 3-axis atomic vector magnetometer operating in the SERF regime, using a single beam path, and capable of operating in Earth's field using field feedback. It has similar sensitivity along all 3 axes that is fundamentally limited by photon and atom shot noise. The scheme uses a high intensity pump pulse to polarize Rb atoms in $\sim 1$ $\mu$s and a sequence of magnetic field pulses applied while the atoms are monitored during free precession. The sequence used provides minimal sensitivity to pulse errors, while also allowing unambiguous discrimination between external magnetic fields and misalignment between laser and magnetic coil axes. [Preview Abstract] |
Friday, May 27, 2016 8:36AM - 8:48AM |
T6.00004: Electromagnetically-induced transparency in Cs and Rb in the same vapor cell Matt Simons, Joshua Gordon, Christopher Holloway We demonstrate simultaneous electromagnetically-induced transparency (EIT) in both cesium and rubidium in the same vapor cell with coincident optical fields. Each atomic system can detect radio frequency (RF) field strengths through modification of the EIT signal. We show that these two systems can detect the same RF field strength simultaneously. This allows us to perform the same measurement in two effective ``laboratories,'' providing an immediate independent reference, which will lead to an SI-traceable RF E-field measurement. We examine the impact of coincident, simultaneous EIT on RF field metrology and the EIT signal. [Preview Abstract] |
Friday, May 27, 2016 8:48AM - 9:00AM |
T6.00005: Sub-picotesla Scalar Atomic Magnetometer with a Microfabricated Vapor Cell Rui Zhang, Rahul Mhaskar We explore the sensitivity limits of scalar atomic magnetometry with a micro-fabricated Cs vapor cell. The millimeter-scale cell is fabricated using silicon Micro-Electro-Mechanical Systems (MEMS) technology. The atomic spin procession is driven by an amplitude-modulated circularly polarized pump laser resonant with the D1 transition in Cs atoms. The precession is detected by an off-resonant linearly polarized probe laser using a balanced polarimeter setup. The probe light is spatially split into two beams to perform a gradiometer measurement. In a magnetic field of magnitude within the range of the earth magnetic field, we measure a sensitivity of less than 150 fT/$\surd $Hz in the gradiometer mode, which shows that the magnetometer by itself can achieve sub-100 fT/$\surd $Hz sensitivitiy. In addition to its high sensitivity, the magnetometer has a bandwidth of nearly 1 kHz due to the broad magnetic resonance inside the small cell. Our experiment suggests the feasibility of a portable, low-power and high-performance magnetometer, which can be operated in the earth's magnetic field. Such a device will greatly expand the range of applications for atomic magnetometers, such as the detection of nuclear magnetic resonance in an unshielded environment. [Preview Abstract] |
Friday, May 27, 2016 9:00AM - 9:12AM |
T6.00006: A Subfemtotesla Atomic Magnetometer Based on Hybrid Optical Pumping of Potassium and Rubidium Yang Li, Hongwei Cai, Ming Ding, Wei Quan, Jiancheng Fang Atomic magnetometers, based on detection of Larmor spin precession of optically pumped atoms, have been researched and applied extensively. Higher sensitivity and spatial resolution combined with no cryogenic cooling of atomic magnetometers would enable many applications with low cost, including the magnetoencephalography (MEG). Ultrahigh sensitivity atomic magnetometer is considered to be the main development direction for the future. Hybrid optical pumping has been proposed to improve the efficiency of nuclear polarization. But it can also be used for magnetic field measurement. This method can control absorption of optical pumping light, which is benefit for improving the uniformity of alkali metal atoms polarization and the sensitivity of atomic magnetometer. In addition, it allows optical pumping in the absence of quenching gas. We conduct experiments with a hybrid optically pumped atomic magnetometer using a cell containing potassium and rubidium. By adjusting the density ratio of alkali metal and the pumping laser conditions, we measured the magnetic field sensitivity better than 0.7 fT/sqrt(Hz). [Preview Abstract] |
Friday, May 27, 2016 9:12AM - 9:24AM |
T6.00007: A High Sensitive Atomic Co-magnetometer for Rotation Rate Measurement Based on K-Rb-21Ne Yao Chen, Sheng Zou, Wei Quan, Yan Lu, Ming Ding, Jiancheng Fang Atomic co-magnetometers use two spin ensembles occupying the same volume in glass vapor cells to suppress their sensitivity to magnetic field noise and leave them sensitive to rotation rate, anomalous fields, etc. Due to the small gyromagnetic ratio of the $^{\mathrm{21}}$Ne atom, an atomic co-magnetometer based on 21Ne is very suitable for rotation rate measurement. Thus, we focus on and report a co-magnetometer for rotation rate measurement based on K-Rb-21Ne. We have developed a rotating co-magnetometer which is calibrated by the rotation of the earth. All the optics in the co-magnetometer have been encased in a bell jar in which the air is pumped away to suppress the air density fluctuation noise. MnZn ferrite is also utilized in the inner most magnetic field shielding system to suppress the magnetic field noise. We have reached rotation rate sensitivity of 2.1 * 10$^{\mathrm{-8}}$ rad/ s / sqrt(Hz) or equivalent magnetic field noise level of 1.4 fT / sqrt(Hz) . The K-Rb-21Ne co-magnetometer has many potential applications for precision measurements, including spin dependent force detecting, Electric Dipole Moment measurement and fundamental symmetry test. [Preview Abstract] |
Friday, May 27, 2016 9:24AM - 9:36AM |
T6.00008: 780nm Rubdium Faraday Anomalous Dispersion Optical Filter with Buffer Gas Xe Junyu Xiong, Longfei Yin, Bin Luo, Hong Guo Faraday anomalous dispersion optical filter (FADOF) is the most commonly used atomic filter, which is usually realized using alkali metal vapor cells. The filter has wide applications fields such as free-space optical communication, lidar and ghost imaging due to its high transmittance and ultra-narrow bandwidth. However, because FADOF is based on the resonant transitions of atoms, and due to the hyperfine structure of alkali elements, the transmittance spectrum of FADOF usually exhibit multi-peak form, which is not appropriate for applications requiring for single peak and will also reduce the signal to noise ratio(SNR). In this work, a 4cm long rubidium cell filled with 1torr Xenon as buffer gas has been used to realize a 780nm FADOF. Under the influence of the buffer gas Xenon, the sidebands of the transmittance spectrum has been removed, and a 780nm FADOF with single peak transmittance spectrum is achieved, which still keeps the high transmittance and ultra-narrow bandwidth. The peak transmittance of the filter is 82.7{\%} if the power loss caused by the optical instruments (38{\%}) is not included, and the bandwidth equals 1.2GHz. [Preview Abstract] |
Friday, May 27, 2016 9:36AM - 9:48AM |
T6.00009: Characterization of antirelaxation-coated vapor cells in high-temperature regime Wenhao Li, Mikhail Balabas, Szymon Pustelny, Arne Wickenbrock, Dmitry Budker Antirelaxation-coated vapor cells are widely used in modern atomic physics experiments due to the coating's ability to maintain spin polarization during wall collisions. We characterize the performance of vapor cells with different coating materials by measuring longitudinal spin relaxation and vapor density at temperatures of up to 90$^{\circ}$C. The longitudinal spin relaxation time ($\tau_{\mathrm{rel}}$) is measured with a modified version of ``relaxation in the dark'' technique [M. Graf et al, Phys. Rev. A 72, 023401 (2005)] and the vapor density ($n$) is obtained by fitting atomic absorption spectrum with linear absorption function. The spin-projection-noise-limited (or atomic shot noise limited) sensitivity for atomic magnetometers is $\delta B_{\mathrm{SNL}} \propto 1/\sqrt{n\tau_{\mathrm{rel}} T}$, where $T$ is measurement time. Therefore, by showing the product of the longitudinal spin relaxation time and the vapor density increases with temperature, we demonstrate the potential of antirelaxation-coated cells in applications of future high-sensitivity magnetometers. [Preview Abstract] |
Friday, May 27, 2016 9:48AM - 10:00AM |
T6.00010: Mx Magnetometry Optimisation in Unshielded Environments Stuart Ingleby, Paul Griffin, Aidan Arnold, Erling Riis, Dominic Hunter Optically pumped magnetometry in unshielded environments is potentially of great advantage in a wide range of surveying and security applications. Optimisation of OPM modulation schemes and feedback in the $M_x$ scheme offers enhanced sensitivity through noise cancellation and decoherence suppression. The work presented demonstrates capability for software-controlled optimisation of OPM performance in ambient fields in the $0.5 G$ range. Effects on magnetometer bandwidth and sensitivity are discussed. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700