Bulletin of the American Physical Society
51st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 65, Number 4
Monday–Friday, June 1–5, 2020; Portland, Oregon
Session J09: Laser Cooling and TrappingLive
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Chair: Trey Porto, University of Maryland, College Park Room: Portland 256 |
Wednesday, June 3, 2020 2:00PM - 2:12PM Live |
J09.00001: A Microwave Trap for Atoms and Molecules sid wright, Thomas Wall, Michael Tarbutt We demonstrate a trap that confines polarizable particles around the antinode of a standing-wave microwave field. The trap relies only on the polarizability of the particles far from any resonances, so can trap a wide variety of atoms and molecules in a wide range of internal states, including the ground state. The trap has a volume of about $10$ cm$^3$, and a depth approaching $1$ K for many polar molecules. We measure the trap properties using $^{7}$Li atoms, showing that when the input microwave power is $610$ W, the atoms remain trapped with a $1/e$ lifetime of 1.76 (12) s, oscillating with an axial frequency of 28.55(5)Hz and a radial frequency of 8.81 (8) Hz. The trap could be loaded with slow molecules from a range of available sources, and is particularly well suited to sympathetic cooling and evaporative cooling of molecules. [Preview Abstract] |
Wednesday, June 3, 2020 2:12PM - 2:24PM Live |
J09.00002: Ball Lens Optical Trap Leo Nofs, Michael A. Viray, Cainan S. Nichols We provide a demonstration of a rubidium MOT with ball lenses. The ball lens design provides a new range of possible improvements towards the goal of miniaturization of MOT and optical molasses systems, as well as improved electric-field control. The ball lenses subtend a sub-percent solid angle from the trapped atoms. The $1.5~$mm diameter ball lenses are embedded in a cubic mounting frame with a side length of about 15~mm that acts as a Faraday cage. The cage reduces the effects of outside fields and variable black body radiation. The 2-mW trap laser beams are collimated onto the ball lenses (Full Width Half Max (FWHM) between $400$ and $750~\mu$m), which generate high-NA, divergent trapping beams that expand to about 6~mm FWHM at the trap location at the center of the cage, with intensities of $3 I_{sat}$. We characterize atom numbers and loading rates, and discuss peculiarities that arise from the highly divergent character of the trapping beams. The ball lens trap is power efficient due to its compact design. It is conducive for MOT operation with low viable magnetic-field gradients, it is well-suited for systems that require specific electromagnetic boundary conditions, and it may be effective at controlling black-body radiation in atomic clocks Rydberg-atom experiments. [Preview Abstract] |
Wednesday, June 3, 2020 2:24PM - 2:36PM Live |
J09.00003: Levy Dynamics of Single Laser-Cooled Atoms Wesley Erickson, Daniel Steck The study of Levy flights of laser-cooled atoms dates back to the early days of laser cooling and trapping. The theory of Levy processes has advanced considerably since then, however, and new aspects of Levy processes can be studied in laser-cooling experiments with a single trapped atom. Through simulations we show that boundary-crossing statistics of a single atom are sensitive to the onset of anomalous diffusion. We find that distributions of first-passage times develop peaks corresponding to Levy flights. We also discuss the implications of the leapover phenomenon of Levy flights in physical experiments. Our results hint at a rich diversity of phenomena in laser-cooling dynamics beyond the studies of power-law tails in the densities of the early experiments. [Preview Abstract] |
Wednesday, June 3, 2020 2:36PM - 2:48PM Live |
J09.00004: $\Lambda$-enhanced sub-Doppler cooling in a grating magneto-optical trap Daniel S. Barker, Eric B. Norrgard, Nikolai N. Klimov, Stephen Eckel We report our observation of sub-Doppler cooling of lithium using a tetrahedral laser beam arrangement, which is produced by a nanofabricated diffraction grating. We are able to capture $10~\%$ of the lithium atoms from a grating magneto-optical trap into $\Lambda$-enhanced $D_1$ gray molasses. The molasses cools the captured atoms to approximately $30~\mu$K. In contrast to results from conventional counterpropagating beam configurations, we do not observe cooling when our optical fields are detuned from Raman resonance. Our results show that grating magneto-optical traps can serve as a robust source of cold atoms for tweezer-array and atom-chip experiments, even when the atomic species is not amenable to sub-Doppler cooling in bright optical molasses. [Preview Abstract] |
Wednesday, June 3, 2020 2:48PM - 3:00PM Live |
J09.00005: Confinement of an alkaline-earth element in a grating magneto-optical trap Peter Elgee, Ananya Sitaram, Daniel Barker, Gretchen Campbell, Nikolai Klimov, Stephen Eckel Cold alkaline-earth atoms are a promising platform for a variety of quantum technologies, in particular for atomic clocks. Such experiments often use a magneto-optical trap (MOT) for initial cooling and trapping, which usually requires a large setup and fine tuned alignment, limiting their potential applications. Here we demonstrate the first grating MOT of strontium, a compact alternative to the typical six-beam MOT. In this MOT, atoms are loaded from a small dispenser source and trapped with the diffraction off of a nanofabricated grating. Thus, such a MOT only uses a single input beam, which cuts down on space and alignment requirements. Our $^{88}$Sr MOT has approximately $4 \times 10^6$ atoms with a temperature of around 5 mK, and a vacuum limited lifetime of over 1 s. These results indicate that compact grating MOT systems could be used for clocks or other quantum devices with alkaline-earth atoms. [Preview Abstract] |
Wednesday, June 3, 2020 3:00PM - 3:12PM Live |
J09.00006: Investigating the possibility of entropy transfer between particles and laser fields during cooling processes John Bartolotta, Jarrod Reilly, Murray Holland We develop and theoretically analyze a gedanken experiment that explores the subtle topic of entropy transfer from particles to laser fields during the process of laser cooling. An ensemble of non-interacting, motionless particles is placed in a lossless optical cavity and is prepared in a mixed state with weights in two ground states, one of which is resonant with the cavity. The particles interact with a coherent state, which is also prepared in the cavity, according to the Jaynes-Cummings Hamiltonian. The particles can decay from an excited state into the non-resonant ground state by spontaneous emission into free space. We track any entropy flow between the ensemble of particles and cavity field throughout this process by calculating the mutual information between the cavity field and an ensemble of auxiliary particles that purify the initial particle state. [Preview Abstract] |
Wednesday, June 3, 2020 3:12PM - 3:24PM Live |
J09.00007: Acoustic Detection with an Optically Trapped Silica Microsphere Jordan Zesch, Diney Ether, Logan Hilberry, Yi Xu, M.G. Raizen An ideal acoustic detector would operate near the quantum limit of sensitivity and with a bandwidth that could resolve the fastest signals of interest. We report here on our progress towards the development of such a detector based on our earlier observation of short-time ballistic Brownian motion, as first predicted by Einstein in 1907. We employ a dual-beam optical tweezer to trap glass microspheres in air, together with a novel detection system that can track the center-of-mass motion with ultra-high resolution in space and in time. High frequency acoustic signals are detected through their perturbations of the microsphere, and the noise floor is set by the quantum nature of light rather than by thermal motion. In addition, our system enables much greater detection bandwidth than existing microphones, including high-frequency resonant sensors. Fast and ultra-sensitive acoustic detection has many potential applications, ranging from the search for dark matter and cosmogenic neutrinos in bubble chambers to localizing the stopping point of protons in a patient's body~for more precise proton cancer therapy. [Preview Abstract] |
Wednesday, June 3, 2020 3:24PM - 3:36PM Live |
J09.00008: Magneto-optical trapping of Rb using planar optics William McGehee, Daniel Barker, Wenqi Zhu, Nikolai Klimov, Amit Agrawal, Stephen Eckel, Vladimir Aksyuk, Jabez McClelland Development of compact devices utilizing laser-cooled atoms is limited by the large physical footprint traditionally required to shape and polarize optical fields using bulk optical elements. Planar optics including photonic integrated circuits, optical metasurfaces, and other diffractive optics offer an alternative path for preparing these optical fields using lithographically produced components. Here, we demonstrate laser cooling of Rb in a grating-type magneto-optical trap using planar optics for beam launching, shaping, and polarization control. Efficient use of light is accomplished using a flat-top laser beam to illuminate the diffraction grating, and the performance is compared to conventional grating MOTs. [Preview Abstract] |
Wednesday, June 3, 2020 3:36PM - 3:48PM On Demand |
J09.00009: Magneto-optical trapping with complicated level structures and geometries Eric Norrgard, Stephen Eckel As interest grows in miniaturization of atomic physics packages, tetrahedral and tetrahedral-like MOTs have received renewed interest, in part because of the advent of nanofabricated diffraction gratings. The grating MOT takes a single, incident laser beam and uses a diffraction grating to produce at least three more beams necessary to form a tetrahedral-like MOT. This simplified setup may prove vital toward miniaturization efforts, such as simplified chip-scale MOTS with a large grating coupler and custom diffraction grating to produce the necessary beams. We investigate the effects of level structure and trapping geometry on MOT parameters. [Preview Abstract] |
Wednesday, June 3, 2020 3:48PM - 4:00PM On Demand |
J09.00010: Laser Trapping of Circular Rydberg Atoms Clément Sayrin, Rodrigo Cortiñas, Maxime Favier, Brice Ravon, Paul Méhaignerie, Yohann Machu, Jean-Michel Raimond, Michel Brune Rydberg are well suited to quantum simulations, quantum optics, quantum information and quantum sensing. Most experiments use low-orbital-angular-momentum levels. The lifetime of these levels about 100us only and the fact that they are not trapped currently limit the measurement times. Circular Rydberg atoms (CRAs) have lifetimes of few tens of ms and can be laser-trapped over long times. Measurement times of several seconds are even realistic when trapping the atoms in a spontaneous-emission inhibiting structure. They would benefit most of current Rydberg-based quantum technologies. I will present our latest experimental results regarding the preparation of long-lived CRAs from laser-cooled Rubidium atoms in a cryogenic environment. We demonstrate their laser trapping in 2D for up to 10ms [1]. The ponderomotive trap is formed by a hollow Laguerre-Gauss laser beam at 1064nm. We observe no loss of atoms over the measurement time. We measure the CRAs lifetime to be a of a few ms, revealing a low temperature of the microwave blackbody radiation. Our results open the route towards novel quantum simulators [2] and to enhanced measurement times in hybrid CQED experiments or quantum sensors using CRAs. [1] R. Cortinas et al., arXiv :1911.02316 [2] T. L. Nguyen et al., PRX 9, 011032 [Preview Abstract] |
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