Bulletin of the American Physical Society
2018 Joint Spring Meeting of the Texas Sections of APS, AAPT, and Zone 13 of the SPS
Volume 63, Number 8
Thursday–Saturday, March 22–24, 2018; Stephenville, Texas
Session B3: APS I - Atomic, Molecular, & Optical Physics |
Hide Abstracts |
Chair: Preet Sharma, Midwestern State University Room: Science 102 |
Friday, March 23, 2018 11:00AM - 11:12AM |
B3.00001: Three-boson spectrum in the presence of 1D spin-orbit coupling: Efimov’s generalized radial scaling law Qingze Guan, Doerte Blume Spin-orbit coupled cold atom systems, governed by Hamiltonians that contain quadratic kinetic energy terms typical for a particle's motion in the usual Schr\"odinger equation and linear kinetic energy terms typical for a particle's motion in the usual Dirac equation, have attracted a great deal of attention recently since they provide an alternative route for realizing fractional quantum Hall physics, topological insulators, and spintronics physics. The present work focuses on the three-boson system in the presence of 1D spin-orbit coupling. In the absence of spin-orbit coupling terms, the three-boson system exibits the Efimov effect: the entire energy spectrum is uniquely determined by the $s$-wave scattering length and a single three-body parameter, i.e., using one of the energy levels as input, the other energy levels can be obtained via Efimov's radial scaling law, which is intimately tied to a discrete scaling symmetry. It is demonstrated that the discrete scaling symmetry persists in the presence of 1D spin-orbit coupling, implying the validity of a generalized radial scaling law in five-dimensional space. The dependence of the energy levels on the scattering length, spin-orbit coupling parameters, and center-of-mass momentum is discussed. [Preview Abstract] |
Friday, March 23, 2018 11:12AM - 11:24AM |
B3.00002: Center of Mass Momentum Dependent Interaction Between Ultracold Atoms. Jianwen Jie, Peng Zhang We show that a new type of two-body interaction, which depends on the momentum of the center of mass (CoM) of these two particles, can be realized in ultracold atom gases with a laser-modulaed magnetic Feshbach resonance (MFR). Here the MFR is modulated by two laser beams propagating along different directions, which can induce Raman transition between two-body bound states. The Doppler effect causes the two-atom scattering length to be strongly dependent on the CoM momentum of these two atoms. As a result, the effective two-atom interaction is CoM-momentum dependent, while the one-atom free Hamiltonian is still the simple kinetic energy. [Preview Abstract] |
Friday, March 23, 2018 11:24AM - 11:36AM |
B3.00003: Two-body scattering resonances in an effectively one-dimensional Rashba-Dresselhaus spin-orbit coupled quantum gas Su-Ju Wang, Qingze Guan, D. Blume Confinement-induced resonances allow for the tuning of the effective one-dimensional coupling constant. When the scattering state associated with the ground transverse mode is brought into resonance with the bound state attached to the energetically excited transverse modes, the atoms interact through an infinitely strong repulsion. This provides a route to realize the Tonks-Girardeau gas. On the other hand, the realization of synthetic gauge fields in cold atomic systems has attracted a lot of attention. For instance, bound-state formation is found to be significantly modified in the presence of spin-orbit coupling in three dimensions. This motivates us to study ultracold collisions between two Rashba-Dresselhaus spin-orbit coupled atoms in a quasi-one-dimensional geometry. We develop a multi-channel scattering formalism that accounts for the external transverse confinement and the spin-orbit coupling terms. The interplay between these two single-particle terms is shown to give rise to new scattering resonances. In particular, we focus our discussions on the case with a singlet two-body interaction. [Preview Abstract] |
Friday, March 23, 2018 11:36AM - 11:48AM |
B3.00004: Degenerate Four-Wave Mixing near the Excitonic Resonances of Bulk MoS$_{\mathrm{2}}$ Brian Ko, Zhenrong Zhang, Alexei Sokolov, Ho Wai Lee, Marlan Scully MoS$_{\mathrm{2}}$ is a two-dimensional semiconductor with a direct bandgap in the visible regime (1.88 eV), making it a promising candidate for optoelectronic and photonic applications, such as Raman enhancement. However, near the bandgap, the photoluminescence of MoS$_{\mathrm{2\thinspace }}$disturbs the Raman signal, reducing enhancement. In the bulk limit, MoS$_{\mathrm{2}}$ transitions to an indirect semiconductor while retaining the direct excitonic transition at 1.88 eV. In our experiment, we observe a four-wave mixing (FWM) signal generated by a bulk MoS$_{\mathrm{2}}$ flake using a broadband coherent anti-Stokes Raman spectroscopy setup. We observe a resonance at 680 nm, corresponding to the energy of the excitonic transition. This resonance occurs due to the increased third-order nonlinear susceptibility at wavelengths near the excitonic transition. This phenomenon could open the path to using MoS$_{\mathrm{2}}$ as a flat substrate for four-wave mixing processes such as coherent anti-Stokes Raman spectroscopy.. [Preview Abstract] |
Friday, March 23, 2018 11:48AM - 12:00PM |
B3.00005: Investigation of the Interaction of Pyridine Complexes and MoS$_{\mathrm{2}}$ Nanoflakes via Raman Spectroscopy Zachary Liege, Weigang Lu, Howard Ho Wai Lee, Alexei Sokolov, Zhenrong Zhang Monitoring chemical reactions in real time has applications ranging from basic chemical analysis of intermediates to catalysis to biochemistry. Raman spectroscopy is a highly selective sensing technique that can give detailed chemical information about an analyte in real time. In this work, we investigate the chemical activity of MoS$_{\mathrm{2}}$ nanoflakes using Raman spectroscopy. Pyridine is used as a Raman probe due to its well-known vibrational spectrum. When mixed with ethanol or water, pyridine forms complexes via hydrogen bonding that shift the Raman peaks in a quantifiable manner. By mixing these complexes with prepared solutions of MoS$_{\mathrm{2}}$ nanoflakes, the effect of the nanoparticles on the interaction of pyridine and its solvent can be measured. Peak ratio analysis indicates that smaller flakes seem to ``accelerate'' the interaction, creating larger peak shifts at much lower concentrations of nanoflakes. This is likely due to the increased ratio of edge sites to surface area of the flakes. [Preview Abstract] |
Friday, March 23, 2018 12:00PM - 12:12PM |
B3.00006: Photonic crystal fiber assisted nano-antenna for tip-enhanced Raman spectroscopy Khant Minn, Blake Birmingham, Brian Ko, Marlan Scully, Howard Lee, Zhenrong Zhang Metallic nano-probes supporting plasmon polariton modes can localize the optical fields at nanoscale for near-field imaging and sensing applications such as tip-enhanced Raman spectroscopes. In this paper, we report the design, fabrication, and far-field characterization of a photonic-plasmonic probe. Our device couples the light highly confined in a photonic crystal fiber with the plasmonic mode on the surface of a needle-shaped nano-antenna. The nano-antenna is grown via electron beam assisted chemical deposition of platinum in the center of a photonic crystal fiber's end facet. By controlling the deposition parameters, the height and base diameter of the antenna can be tuned to optimize plasmonic resonance conditions. Optical spectra and mode profiles transmitted through the probes are analyzed to characterize the optical response of the probes. Far field side emission from the probes demonstrates the excitation of surface plasmons on the antennae. The probe can be implemented into tip-enhanced Raman microscope setup to obtain topographic and chemical spectroscopic information to study light-matter interaction at the nanoscale. [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