Bulletin of the American Physical Society
APS March Meeting 2019
Volume 64, Number 2
Monday–Friday, March 4–8, 2019; Boston, Massachusetts
Session F25: General Atomic, Molecular, and Optical Physics I: NV Magnetometry, Lasing, and Casimir Forces |
Hide Abstracts |
Sponsoring Units: DAMOP Chair: Kevin Wright, Dartmouth College Room: BCEC 160A |
Tuesday, March 5, 2019 11:15AM - 11:27AM |
F25.00001: NV-Diamond Magnetometry in the NV-NV Interaction Limit Connor Hart, Erik Bauch, Jennifer Schloss, Raisa Trubko, Matthew J Turner, Diana Prado Lopes Aude Craik, Ronald L Walsworth In nitrogen-vacancy (NV) ensembles in diamond, the magnetic sensitivity is commonly limited by a bath of other impurity spins, which decoheres the NV sensor spins. We demonstrate mitigation of NV-bath interactions by RF control of the spin bath or dynamical decoupling of the NV centers. In this regime, mutual NV-NV dipolar interactions dominate the ensemble spin properties (T2, T2*). These techniques may yield improved DC and AC magnetic sensitivity up to a limit set by NV-NV dipolar interactions. For example, we show NV ensemble coherence times under XY8-n dynamical decoupling protocols limited by instantaneous diffusion. We present progress toward mitigating NV-NV interactions while preserving magnetic sensitivity, and conversely we outline ideas to leverage strong NV-NV interactions to further improve magnetic sensitivity. |
Tuesday, March 5, 2019 11:27AM - 11:39AM |
F25.00002: A high-speed, strain-free NV-diamond magnetic imager for neuroscience Jennifer Schloss, Connor Hart, Matthew J Turner, Patrick Jan Scheidegger, Erik Bauch, Ronald L Walsworth Real-time wide-field imaging of dynamic magnetic fields finds broad applications from condensed matter physics to neuroscience. We present a broadband, high-sensitivity magnetic imaging system designed to map magnetic fields from arrays of firing neurons. The imager employs pulsed Ramsey protocols on an ensemble of nitrogen-vacancy (NV) centers in diamond, and it achieves enhanced sensitivity, bandwidth, and uniformity compared to conventional continuous-wave optically detected magnetic resonance (CW-ODMR) imaging. We show further improvements though implementing double-quantum coherence imaging, which mitigates inhomogeneous crystal-lattice strain and microwave gradients over of the field-of-view, and we demonstrate novel noise cancellation protocols. We present first images of nontrivial dynamic magnetic fields and steps toward real-time imaging of bio-magnetic fields from live, firing neurons. |
Tuesday, March 5, 2019 11:39AM - 11:51AM |
F25.00003: Large-Scale Uniform Optical Focus Array Generation with a Phase Spatial Light Modulator Donggyu Kim, Alexander Keesling, Ahmed Omran, Harry Levine, Hannes Bernien, Mikhail Lukin, Dirk R. Englund Uniform optical focus arrays are needed in a range of applications including multifocus multiphoton microscopy and multi-beam laser machining. Recently, such focus arrays were also developed as an essential tool for controlling ultra-cold atoms for quantum information processing. A challenge in these applications is to efficiently produce uniform large-scale optical focus arrays (LOFAs). Here, we present a new method for generating uniform LOFAs using a phase spatial light modulator. By identifying and removing undesired phase rotation in the iterative Fourier-transform algorithm, we demonstrate rapid and reliable generation of LOFAs containing O(103) optical foci with > 98% intensity uniformity. |
Tuesday, March 5, 2019 11:51AM - 12:03PM |
F25.00004: Continuous frequency-domain multiplexing of heralded single-photon sources Thomas Parker, Thomas Hiemstra, Peter Humphreys, Andreas Eckstein, Brian Smith, Steve Kolthammer, Ian Walmsley, Michal Karpinski, Mark Beck, Johannes Tiedau Single-photon sources are an important tool for experiments in quantum optics and quantum information [1]. Heralded single-photon sources based on non-linear processes such as parametric down-conversion are ubiquitous. However, significant limitations arise due to the probabilistic nature of photon pair emission, as well as the possibility of generating more than one photon per pump pulse. In a technique known as multiplexing [2-3], the probability of generating a single photon can be increased by switching the output from multiple sources into a single channel. |
Tuesday, March 5, 2019 12:03PM - 12:15PM |
F25.00005: Cooperative ultrastrong atom-light coupling from an effective mapping picture of single-photon superradiance. Yao Zhou, Zihao Chen, Jung-Tsung Shen As a manifestion of cooperative atom-light interaction from a cluster of atoms, single-photon superradiance has attracted considerable attention for its salient feature of a fast collective spontaneous emission rate and an enhanced coupling strength. It is found that when a cluster of atoms in a dense atom cloud or spatially distributed QED system obtains a largest collective spontaneous emission rate, which is the superadiant emission rate, their optical response is always indistinguishable with a single effective atom. From such effective mapping picture, one can obtain the superradiance conditions for a QED system. Specifically, we have analytically calculated the superradiance conditions for atoms trapped along a waveguide and for atoms coupled to whispering gallery mode resonators and computationally validated them. Based on strong coupling regime, an ultrastrong coupling strength proportional to atom number is accessible by exploiting the superradiance condition, and meanwhile the coherence between atoms remains without distorting the profile of optical response from a single atom. The ultrastrong coupling strength would benefit in the design of ultrafast optical devices, atomic mirror, and controllable optic add/drop filter. |
Tuesday, March 5, 2019 12:15PM - 12:27PM |
F25.00006: Χ2 Optical Frequency Comb by Cavity Phase Matching Ni Xin, Zhenda Xie, ShuWei Huang, Baicheng Yao, Huaying Liu, Nicolò Sernicola, Xinjie Lv, Gang Zhao, Zhenlin Wang, Shining Zhu
|
Tuesday, March 5, 2019 12:27PM - 12:39PM |
F25.00007: Terahertz-optical intensity grating for creating high-charge, attosecond electron bunches Jeremy Lim, Yidong Chong, Liang Jie Wong Ultrashort electron bunches are useful for applications like ultrafast imaging, coherent radiation production, and compact sources of accelerated electrons. Currently, however, the shortest achievable bunches, at attosecond time scales, have only been realized in the single or very few electron regime, limited by Coulomb repulsion and electron energy spread. We will present ab initio simulation results and theoretical analysis which show that highly-charged bunches are achievable by subjecting moderately-relativistic (few MeV-scale) electrons to a superposition of terahertz and optical pulses. Using realistic electron bunches and laser pulse parameters which are within the reach of current compact setups, we provide two detailed examples: one with final bunches of ~1 fC contained within sub-400 as durations and 8 micron radii, and one with bunches of > 25 electrons contained within 20 as durations and 15 micron radii. Our results reveal a route to achieve such extreme combinations of high charge and attosecond pulse durations with existing technology. |
Tuesday, March 5, 2019 12:39PM - 12:51PM |
F25.00008: Investigating the nonlinear refraction index of Rb vapor by scanning the laser frequency through the atomic resonances. CLAUDIA PATRICIA MEJIA VILLAGRÁN, Alexandre Andrade Cavalcanti de Almeida, Sandra Sampaio Vianna We have observed self-focusing and defocusing in rubidium vapor by scanning the laser frequency through atomic resonances. These phenomena originate from the third order electric susceptibility, and have been used to measure the nonlinear refractive index of materials with the well-known technique Z-scan. However, few experimental measurements have been carried out near the resonances of atomic systems. In our experiment we scan the frequency of a diode laser through the resonances of rubidium vapor, contained in a fixed cell. The transmittance of the beam as a function of frequency detuning is detected after a small aperture, for different laser intensities and aperture radius. The theoretical model is a two-level system considering velocity distribution. A reasonably good fit of the experimental data is obtained, indicating that it is possible to measure the intensity-dependent term of the refractive index with this technique. |
Tuesday, March 5, 2019 12:51PM - 1:03PM |
F25.00009: Revisiting the Photon-Drag Effect in Gold Films Jared H Strait, Glenn Holland, Wenqi Zhu, Cheng Zhang, Amit Agrawal, Domenico Pacifici, Henri J Lezec The photon-drag effect, the rectified current in a medium induced by conservation of momentum of absorbed or redirected light, is a unique probe of the detailed mechanisms underlying radiation pressure. We revisit this effect in gold, a canonical Drude metal for infrared frequencies. We discover that the signal for p-polarized illumination in ambient air is affected in both sign and magnitude by adsorbed molecules, opening previous measurements for reinterpretation. Further, we show that the intrinsic sign of the photon-drag effect is contrary to the prevailing intuitive model of direct momentum transfer to free electrons. |
Tuesday, March 5, 2019 1:03PM - 1:15PM |
F25.00010: Optical Forces between Coupled PT-symmetric Waveguides Mohammad-Ali Miri, Michele Cotrufo, Andrea Alu Evanescent wave coupling between two dielectric waveguides results in an optical force between the waveguides. This force is attractive (repulsive) when the coupled waveguide system is excited with the symmetric (anti-symmetric) mode and is transverse to the axis of wave propagation. Through energy conservation considerations, it is shown that the optical bonding force is proportional to the gradient of the propagation index of the symmetric and anti-symmetric supermodes with respect to the distance between the two guides. However, when gain or loss is involved in the waveguides, this derivative becomes undefined at an exceptional point singularity. In order to investigate forces at the exceptional point singularities, here we consider a PT-symmetric model of two coupled waveguides and calculate the force through Maxwell’s stress tensor. Our results show that the optical bonding force is finite at the exceptional point. In addition, we find an extra force component which is directed along the axis of propagation. |
Tuesday, March 5, 2019 1:15PM - 1:27PM |
F25.00011: Floquet dynamics of classical and quantum cavity fields Ivar Martin We show that the time-dependence of electromagnetic field in a parametrically modulated cavity can be effectively analyzed using a Floquet map. The map relates the field states separated by one period of the drive; iterative application of the map allows to determine field configuration after arbitrary number of drive periods. For resonant and near-resonant drives, the map has stable and unstable fixed points, which are the loci of infinite energy concentration in the long time limit. The Floquet map method can be applied both to classical and quantum massless field problems, including the dynamical Casimir effect. The stroboscopic time evolution implemented by the map can be interpreted in terms of the wave propagation in a curved space, with the fixed points of the map corresponding to the black hole and white hole horizons. More practically, the map can be used to design protocols for signal compression/decompression, cavity cooling, and photon sensing. |
Tuesday, March 5, 2019 1:27PM - 1:39PM |
F25.00012: Reducing detrimental electrostatic effects in precision Casimir force measurements using argon ion bombardment and UV light Mingyue Liu, Jun Xu, Robert Schafer, Vladimir Mikhailovich Mostepanenko, Galina Leonidovna Klimchitskaya, Umar Mohideen In precision Casimir force measurements between two neutral and grounded surfaces, the role and effect of electrostatic forces have to be fully understood in vacuum. The two Au coated surfaces can be contaminated with adsorbates leading to potential electrostatic patches. We have used 500 eV Ar ion bombardment of the surfaces and UV cleaning to remove the adsorbates prior to Casimir force measurements. The measurements were performed by means of dynamic atomic force microscopy operated in frequency shift mode. The force was measured between an Au coated hollow glass sphere attached to a Si cantilever and an Au coated silicon plate. To improve the sensitivity of the cantilever by reducing its spring constant, it was etched using concentrated KOH solution prior to attachment of the sphere. The residual potential difference between the Au sphere and the plate was reduced using Ar ion bombardment and UV light and checked to be independent of the sphere-plate separation. The measured Casimir force has been compared to theoretical prediction of the Lifshitz theory. For the distance ranges measured the experimental data are consistent with the electric permittivity of Au using the lossless plasma model behavior at zero frequency and tabulated optical data at all other frequencies. |
Tuesday, March 5, 2019 1:39PM - 1:51PM |
F25.00013: Casimir Force Measurement in the Cylinder-Plate Geometry Robert Schafer, Mingyue Liu, Jun Xu, Roya Zandi, Umar Mohideen The Casimir effect has broad implications for the creation and operation of MEMS devices operating in the submicron regime. Experimental studies of the Casimir effect with smooth boundaries have primarily involved simple geometries such as the sphere-plate configuration. As Casimir forces are strongly dependent on the boundary shape, more complicated geometries will introduce modifications in the collective charge fluctuation anisotropy induced by the scattering of the zero point photons. In this work, we examine the Casimir forces between a cylinder and a sphere in a UHV environment, particularly examining the boundary effects of the 1-D role of the cylinders. To reduce the ellipticity of the cylinders involved, we have used an etched glass optical fiber, coated with Au to provide a conductive surface. Co-location of the sphere and cylinder was achieved using a piezoelectric stage with a capacitive sensor controlled PID loop. To eliminate residual electrostatic effects from surface adsorbates and resulting patches, we utilize in situ Ar ion bombardment and UV cleaning in the high vacuum environment prior to the measurement of the Casimir force. We compare the experimental results to theories using both the Proximity Force Approximation and the multiple scattering approach. |
Tuesday, March 5, 2019 1:51PM - 2:03PM |
F25.00014: Quantum sensing of large nuclear-spin clusters in diamond with atomic-scale resolution Mohamed Abobeih, Joe Randall, Conor Bradley, Hans Bartling, Michiel Bakker, Maarten Degen, Viatcheslav Dobrovitski, Tim Hugo Taminiau The ability to resolve the 3D structure of large clusters of nuclear spins has the potential to be a revolutionary tool for NMR imaging of single molecules and solids. The nitrogen-vacancy (NV) center in diamond is a promising platform to achieve this goal. At the same time, its local nuclear spin environment already provides a model system to study, develop and test such new methods1. Here we report on quantum sensing and atomic structure analysis of a 10+ nuclear-spin cluster in diamond with atomic-scale resolution. We develop pulse sequences to coherently control the nuclear spins forming the cluster, and directly measure the pairwise dipolar couplings between the nuclear spins with high precision. We then utilize the measured nuclear-nuclear couplings between the spins to determine their 3D structure with atomic-scale resolution. The methods developed in this work can be extended to samples outside the diamond, and mark an important step towards the ultimate goal of structural imaging of single molecules and proteins. |
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