Atomtronics-Photonics Integration with UItracold Strontium
Abstract
analogous to electronic components, promises to realize quantum sensors for position, navigation,and timing (PNT) with orders of magnitude better performance than their classical counterparts.However, this vision has been an elusive dream for almost 20 years with the so-far exploredmagnetic trapping platforms. We propose a transformational advance to realize atomtronic devicesthat fulfill their promises.This project will develop the foundations of a novel class of quantum devices based oncircuits of matter-waves of strontium that are trapped, controlled, and guided by the evanescentfields of underlying photonic nanowaveguide circuits. Strontium atoms will be trapped by twocolorevanescent fields emanating from the top of nanowaveguides. These two fields causerepulsive and attractive forces on the atoms and their distinct decay lengths, when combined, willlead to the formation of a local sharp potential minimum at 200 nm from the top surface of thewaveguide, for reasonable powers of a few to ten mW of light guided in the waveguides. Bychoosing both fields to be magic wavelengths for a microKelvin-cooling transition, and using lasercooling techniques unique to strontium, we anticipate high phase-space densities, natural modematching,and continuous loading into the atomtronic device. Strontium s mass-88 isotope enablesa 100-times reduction below the rubidium value of dephasing atom-atom interactions, afundamental limit on the matter-wave spatiotemporal coherence. Furthermore, strontium s nonmagnetic/electric singlet ground state eliminates magnetic/electric field sensitivity.Pristine nanophotonic potentials, leading to long-lived matter-wave coherence andsensitivity, are feasible through a novel state-of-the-art aluminum-nitride (AlN) nanowaveguideplatform suitable for the blue-wavelength spectrum, as required for strontium. High qualityepitaxial AlN enables low-loss photonic integrated circuits (PIC) and high-Q optical resonatorsoperating deeper into the short wavelengths than amorphous waveguide materials, such as siliconnitride, and are more immune to parasitic nonlinear effects such as two-photon absorption andphotothermal phenomena.In this project we will develop high Q multi-wavelength micro-ring resonators and newhighly-efficient grating couplers unique for trapping and manipulating strontium atoms. Thesedevices and a fully-developed ultra-high vacuum cold-atom apparatus with a load-lock and brightstrontium source will crucially enable a tightly integrated rapid design-prototype test cycle. Wewill trap matter-waves of strontium on the evanescent fields of micro-ring resonators, and usingBragg pulses, split them into counterrotating matter-waves, and recombine them to observe matterwaveinterference. Upon rotation of the apparatus, the observed gyroscopic effect will be the basisfor a paradigm-shifting class of trapped-atom PIC devices for PNT.This platform provides unique flexibility in designing complex trapping potentials andperfect matching of any optical field to manipulate and probe the matter waves. Thesebreakthroughs are the incubating steps towards the long-term goal of realizing photonic-integratedatomtronic PNT devices with unsurpassed precision, compactness, and robustness with allcomponents on-chip, including: lasers, cold-atom sources feeding atom-laser sources, sensors,simulators, and computers based on matter-wave interference.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 31, 2020
- Source ID
- N000142012693
Entities
People
- Julio Barreiro
Organizations
- Office of Naval Research
- United States Navy
- University of California, San Diego