Bulletin of the American Physical Society
52nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 66, Number 6
Monday–Friday, May 31–June 4 2021; Virtual; Time Zone: Central Daylight Time, USA
Session E09: Laser and Nonlinear OpticsLive
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Chair: Carlos Trallero, University of Connecticut |
Tuesday, June 1, 2021 2:00PM - 2:12PM Live |
E09.00001: Universality in one-dimensional scattering with general dispersion relations Yidan Wang, Michael Gullans, Xuesen Na, Alexey V Gorshkov Many synthetic quantum systems allow particles to have dispersion relations that are neither linear nor quadratic functions. Here, we explore single-particle scattering in one dimension when the dispersion relation is(k) =±|d|km, where m≥2 is an integer. For a large class of scattering problems, we rigorously prove that when there are no half bound states at zero energy, the S-matrix evaluated at an energy E→ 0 converges to a universal limit that is only dependent on m. We study impurity scattering problems in which a single-particle in a one-dimensional waveguide scatters off of an inhomogeneous, discrete set of sites locally coupled to the waveguide. We also give a generalization of a key result in quantum scattering theory known as Levinson's theorem—which relates the scattering phases to the number of bound states—to impurity scattering for these more general dispersion relations. |
Tuesday, June 1, 2021 2:12PM - 2:24PM Live |
E09.00002: Using aberrations for small waists and degenerate optical cavities Matthew Jaffe, Claire Baum, Lukas Palm, Jon Simon Optical resonators enable strong interactions between single photons and atoms. Despite their ubiquity in both classical and quantum optics, relatively little work has explored these resonators beyond their simplest description: paraxial, quadratic optics. That description is inadequate for cavities with high-finesse, small waist, and/or many degenerate modes. In this talk I will present new theoretical frameworks to describe optical cavities beyond this first approximation. I will show experimental data validating the aberrated spectra of a non-planar, 17 μm-waist degenerate resonator using intracavity lenses compatible with finesse over 105. I will discuss the engineering of spectrum aberrations, including a paraxially unstable geometry stabilized by aberrations. This cavity will be used to explore fractional quantum Hall physics with Rydberg polaritons. |
Tuesday, June 1, 2021 2:24PM - 2:36PM Live |
E09.00003: Development of laser system for atom interferometric detection of gravitational waves and dark matter Tejas Deshpande, Kenneth DeRose, Jonah Glick, Tim Kovachy Long-baseline atom interferometers (AIs) are rapidly developing tools for precise and accurate tests of fundamental physics. This work focuses on a 100 meter baseline AI known as the Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS-100). The ultimate goal of instruments in the MAGIS family, with progressively longer baselines (e.g. 1 kilometer) in newer generations, is the detection of gravitational waves (GWs) and dark matter (DM). For GW detection, MAGIS-100 exploits the clock transition in Strontium-87 (87Sr) at 698 nm. For DM detection, two isotopes 87Sr/88Sr will be simultaneously driven using the Bragg transition near 679 nm. |
Tuesday, June 1, 2021 2:36PM - 2:48PM Live |
E09.00004: Gouy phase-matched angular and radial mode conversion in four-wave mixing Andrew Daffurn, Rachel Offer, Erling Riis, Paul F Griffin, Sonja Franke-Arnold, Aidan S Arnold We use four-wave mixing in a heated rubidium vapour to couple the orthogonal azimuthal and radial mode numbers of Laguerre-Gaussian beams. The selection rules for the angular mode number are governed by angular momentum conservation, while the role of the radial mode number is more esoteric. One would not normally expect these orthogonal components to interact but we demonstrate experimentally that a clean Laguerre-Gauss mode LGlp = LG01 can be generated by converting LG10 and LG-10 near-infrared pump beams -- but only if the length of the atomic medium exceeds the Rayleigh range. This leads to strikingly different conversion behaviour in thick- and thin-medium regimes; with the Gouy phase, and it's relative importance in each regime, the key to understanding this conversion. Our experimental investigation of the transition between these regimes bridges the gap between previous experiments in atomic thick media and work in nonlinear crystals. This sets a clear starting point to explore efficient radial-to-azimuthal and radial-to-radial mode conversion in the thick-medium regime. |
Tuesday, June 1, 2021 2:48PM - 3:00PM Live |
E09.00005: Active Pointing Stabilization of MW Peak-Power UV Laser Beam for Laser-Assisted Charge Exchange Martin J Kay, Abdurahim Rakhman, Sarah M Cousineau The Laser-Assisted Charge Exchange (LACE) experiment at the Spallation Neutron Source (SNS) accelerator in Oak Ridge National Lab aims to overcome long-standing limitations associated with the foil-based charge stripping technique to produce high-intensity proton beams. Pointing stability of the high energy (3 MW peak-power at 10 Hz) UV laser (355 nm) beam at the sub-mm level is critical to maintain high efficiency and high reliability of the experiments. An un-evacuated laser transport line (LTL) was retrofitted into the accelerator tunnel to transport the laser beam 65 m from a separate building above ground to the laser-particle interaction point (IP). Due to the high laser power and improvised nature of the LTL, the laser-LTL system suffers from pointing instabilities at the IP in the form of drift and pulse-to-pulse jitter. Pointing instabilities are caused by thermal effects on the optical components, mechanical vibrations and temperature fluctuations along the LTL. A closed-loop beam drift stabilization system was developed using a CMOS camera, LabVIEW based computer image processing, and a piezo-driven steering mirror. The system is capable of making corrections to the pointing at the optimal rate of 10 Hz with high reliability and high position detection accuracy in high radiation environments. A laser beam pointing stability of 3.2 μrad (rms) with a corresponding beam drift of 200 μm (rms) has been achieved at the IP located 65 m away from the laser. |
Tuesday, June 1, 2021 3:00PM - 3:12PM Live |
E09.00006: High-Harmonic Generation in the Water Window from mid-IR Laser Sources Keegan Finger, David Atri-Schuller, Nicolas Douguet, Klaus R Bartschat, Kathryn Hamilton Light sources situated in the water window, which spans the K-edges of carbon and oxygen, can be used to image biological molecules in their natural aqueous environments [1]. These soft X-rays can be produced, e.g., by synchrotron radiation, X-ray free-electron lasers, or high-harmonic generation from mid-IR lasers, with the latter demonstrating the most promise for live-cell imaging with femtosecond time resolution [2]. However, describing harmonic generation in the mid-IR regime is a computationally difficult task, particularly if multi-electron effects are to be included in the calculation. We investigate the harmonic response of neon atoms to mid-IR laser fields (2000−3000 nm) using both a single-active electron (SAE) model [3] and the fully ab initio all-electron R-Matrix with Time-dependence (RMT) method [4]. The laser peak intensity and wavelength are varied to find optimal parameters for high-harmonic imaging in the water window. Comparison of the SAE and RMT results shows excellent agreement between the resulting spectra, and parameters such as the cut-off frequency predicted by the classical three-step model. |
Tuesday, June 1, 2021 3:12PM - 3:24PM Live |
E09.00007: Strong-field control of the plasmonic response in core-shell nanoparticles Jeffrey A Powell, Jianxiong Li, Adam Summers, Seyyed Javad Robatjazi, Erfan Saydanzad, Christopher Sorensen, Daniel Rolles, Matthias F Kling, Carlos A Trallero, Uwe Thumm, Artem Rudenko The strong-field control of plasmonic nanosystems indicates new perspectives for non-linear plasmonic spectroscopy and petahertz electronics. However, questions remain regarding the nature of non-linear light-matter interactions at sub-wavelength spatial and ultrafast temporal scales. We investigated the non-linear plasmonic response of Au-nanoshells with a SiO2-core to an intense laser pulse. Our measured strong-field-ionization photoelectron energy spectra from these core-shell nanoparticles display a striking transition between the weak-field (linear-response) to the strong-field (nonlinear-response) regime. This observed transition agrees with the prediction of our modified Mie–theory simulation that incorporates the non-linear dielectric nanoshell response. The demonstrated optical control of the non-linear plasmonic response in prototypical core-shell nanoparticles paves the way towards ultrafast switching and opto-electronic signal modulation with more complex nanostructures. |
Tuesday, June 1, 2021 3:24PM - 3:36PM Live |
E09.00008: Strong-field photoemission from plasmonic nanoparticles Erfan Saydanzad, Jeffrey A Powell, Jason Li, Seyyed Javad Robatjazi, Adam Summers, Christopher Sorensen, Daniel Rolles, Matthias F Kling, Carlos A Trallero, Artem Rudenko, Uwe Thumm We model strong-field ionization from metal nanoparticles within a semi-classical approach in two distinct steps: (i) electron emission by an intense IR laser pulse using a quantum tunneling model and (ii) photoelectron propagation to the detector in the presence of the incident laser and induced plasmonic fields within a classical trajectory approach [1,2]. Based on simulated photoelectron-momentum distributions for 5 to 70 nm diameter gold nanospheres at two laser intensities, we scrutinize the effects of (i) electron-electron, (ii) electron-residual charge interactions, (iii) photoelectron rescattering and recombination, and (iv) electron temperature in comparison with measured velocity-map-image photoelectron spectra [3,4]. |
Tuesday, June 1, 2021 3:36PM - 3:48PM Live |
E09.00009: Nonlinear absorption in interacting Rydberg EIT spectra on two-photon resonance Annika Tebben, Clement Hainaut, Andre Salzinger, Sebastian Geier, Titus Franz, Thomas Pohl, Martin Gärttner, Gerhard Zürn, Matthias Weidemüller We experimentally investigate the nonlinear transmission spectrum of coherent light fields propagating through a Rydberg-EIT medium with strong atomic interactions. In contrast to previous investigations, which have largely focused on resonant control fields, we explore here the full two-dimensional spectral response of the Rydberg gas. Our measurements confirm previously observed spectral features for a vanishing control-field detuning that are explainable by existing theories, but also reveal significant differences on two-photon resonance. In particular, we find qualitative deficiencies of mean-field models and rate-equation simulations in describing the nonlinear probe-field response under EIT conditions, suggesting spectral signatures of an interaction-induced resonance with laser-dressed entangled pair states. While this effect is captured by the third-order nonlinear susceptibility that accounts for pair-wise interaction effects, the experiments show that many-body processes beyond such two-body effects play a significant role already at surprisingly low probe-field intensities. These results suggest that a more complete understanding of Rydberg-EIT and emerging photon interactions requires to go beyond existing simplified models as well as few-photon theories. |
Tuesday, June 1, 2021 3:48PM - 4:00PM On Demand |
E09.00010: Reduction of laser intensity noise over 1 MHz band for single-atom trapping Yu Wang, Kenneth Wang, Jessie Zhang, Yichao Yu, Kang-Kuen Ni, Jonathan Hood Low noise lasers are required in a variety of scientific applications including optical communication, quantum key distribution, and atom trapping. We present a general scheme for broadband noise reduction up to 1 MHz with a large dynamic range by directly acting on the laser beam. We reduce the intensity noise of a high-power 671nm laser beam from a sum-frequency generation (SFG) setup by using an electro-optic modulator (EOM) and acousto-optic modulator (AOM) in series. The EOM reduces noise at high frequency (10 kHz to 1 MHz), while the AOM sets the average power of the light and reduces noise at low frequency (up to 10 kHz). The light is then used to trap single sodium atoms in an optical tweezer, where the lifetime of the atoms is limited by parametric heating due to laser noise at twice the trapping frequency. With our noise eater, the noise is reduced by up to 15 dB at these frequencies and the lifetime of the atom in the optical tweezer is increased by an order of magnitude to around 6 seconds, which is favorable in the future applications of quantum information and simulation with neutral atom tweezer arrays. |
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