Compact robust testbed for cold-atom clock and sensor applications


OBJECTIVE: Develop a compact robust testbed that can be fielded aboard a mobile Navy platform to validate the performance of cold-atom technology applications such as magnetometry, inertial navigation, gravity gradiometry, timekeeping and frequency synthesis. DESCRIPTION: Cold-atom systems (temperatures in the vicinity of the recoil limit, about 1 microkelvin) provide the best oscillators that are available in the laboratory. For example, atomic fountain clocks now provide the US national standard realization of the second, and are the most accurate clocks contained in the DoD Master Clock ensemble. Cold atom devices have proven or potential advantages over competing technologies in laboratory-based implementations of applications such as magnetometry, gyroscopy, accelerometry, gravimetry, gravity gradiometry, timekeeping and frequency synthesis. Recognizing the much greater precision that is possible when atomic optical transitions are used as frequency standards as compared to microwave transitions, the General Council on Weights and Measures has noted the likely future redefinition of the second in terms of an optical transition. Such an optical atomic clock will have to be realized in a cold-atom system. The remarkable advances made in cold-atom science during the past twenty-five years, accompanied by great improvements in optical technology, now make cold-atom measurements a standard in precision measurement laboratories. The maturing state of laboratory techniques in this area suggests that it is timely to begin testing cold-atom technology on Navy platforms, to ascertain whether the great advantages it displays in a controlled laboratory environment can also be realized by warfighters. This Topic calls for the development of a cold-atom testbed that can be deployed aboard a mobile Navy platform, to demonstrate functions relevant to navigation, timekeeping, sensing or communication. The testbed must offer turnkey generation of a laser-cooled cloud of atoms in a vacuum cell that can be sustained for a sufficient length of time to demonstrate functions of interest. It must require no resources other than footprint space and standard electrical power from the Navy platform and must meet specific platform requirements for test instrumentation. The testbed is not intended to be a candidate to replace any particular device that is currently installed on a Navy platform. It would be deemed to be highly successful if, for example, it were accepted into Trident Warrior experimental trials. The previous paragraph is a complete description of the requirements of this Topic. There is no preference for platform or platforms (whether subsurface, surface, land or air), no preference for function or functions, no preference for atom, no minimum size of cloud, no minimum function data acquisition time. These will simply be ranking factors in the competition. PHASE I: The deliverable of Phase I will be a design report for the candidate system, accompanied by engineering drawings. PHASE II: The deliverable of Phase II will be a working system as proposed in Phase I, modified as appropriate by findings of research conducted during Phase II. PHASE III: The deliverable of Phase II will be delivered to a relevant research laboratory in the Shore Establishment (e.g. NRL, USNO or NAVAIR Pax River, all of which have technical expertise in this area) for test and validation. This will be focused on the issue of whether the delivered system meets the standard for inclusion in exercises such as Trident Warrior. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Although the system proposed here is intended to serve as a testbed on a Navy platform, a functional system of this type would be of great interest to the research and development community. For example, although Bose-Einstein condensation of atomic gases was first demonstrated by ONR grantees in 1995, and the basic experimental principles are openly published and well understood, its attainment in a laboratory environment remains challenging due to the complexity of the coordinated laser, magnet and vacuum systems that are required. Industrial infrastructure did not exist five years ago, but ONR SBIR support has resulted in the development of a number of commercial entities which have made remarkable progress on the necessary components of such a testbed, e.g. ColdQaunta, Vescent Photonics, AOSense and Triad Technologies. In fact, two of these SBIR contractors, ColdQuanta and Vescent Photonics, have recently started successful commercial sales in the academic research markets, of cold-atom apparatus developed with ONR support. These products do not have the functionality of the system proposed in this topic; they are rather steps along the path towards establishing a commercial infrastructure to supply low-cost, reliable and standard components. In addition, we know of larger entities, such as Honeywell, which have instituted cold atom R & D projects with their own funding. There are also applications in the academic research sector in which many universities wish to provide training to students in cold-atom applications, but they face barriers to low-cost entry. A testbed of this type would substantially reduce the technical barriers to entry to other prospective participants in the defense electronics industry, REFERENCES: 1) Simplified system for creating a Bose-Einstein condensate, HJ Lewandowski, DM Harber, DL Whitaker, and EA Cornell, J. Low Temp. Phys., Vol. 132, Nr. 5, Springer (2003), p. 309-367 2) Atom Chips, ed. Jakob Reichel and Vladan Vuletic (Wiley-VCH, New York 2011) 3) Magnetic microtraps for ultracold atoms, Jzsef Fortgh and Claus Zimmermann, Rev. Mod. Phys. 79, 235 (2007)

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