196 research outputs found
Atom Interferometry in Space: Thermal Management and Magnetic Shielding
Atom interferometry is an exciting tool to probe fundamental physics. It is
considered especially apt to test the universality of free fall by using two
different sorts of atoms. The increasing sensitivity required for this kind of
experiment sets severe requirements on its environments, instrument control,
and systematic effects. This can partially be mitigated by going to space as
was proposed, for example, in the Spacetime Explorer and Quantum Equivalence
Principle Space Test (STE-QUEST) mission. However, the requirements on the
instrument are still very challenging. For example, the specifications of the
STE-QUEST mission imply that the Feshbach coils of the atom interferometer are
allowed to change their radius only by about 260 nm or 2.6E-4% due to thermal
expansion although they consume an average power of 22 W. Also Earth's magnetic
field has to be suppressed by a factor of 10E5. We show in this article that
with the right design such thermal and magnetic requirements can indeed be met
and that these are not an impediment for the exciting physics possible with
atom interferometers in space.Comment: v2: minor changes to agree with published version; 8 pages, 6 figure
Choice of the Miniature Inertial Optomechanical Sensor Geometric Parameters with the Help of Their Mechanical Characteristics Modelling
In this paper, the mechanical characteristics of a miniature optomechanical accelerometer, similar to those proposed for a wide range of applications, have been investigated. With the help of numerical modelling, characteristics such as eigenfrequencies, quality factor, displacement magnitude, normalized translations, normalized rotations versus eigenfrequencies, as well as spatial distributions of the azimuthal and axial displacements and stored energy density in a wide frequency range starting from the stationary case have been obtained. Dependencies of the main mechanical characteristics versus the minimal and maximal system dimensions have been plotted. Geometries of the optomechanical accelerometers with micron size parts providing the low and the high first eigenfrequencies are presented. It is shown that via the choice of the geometrical parameters, the minimal measured acceleration level can be raised substantially
A laser dilatometer setup to characterize dimensionally stable materials from 100 K to 300 K
In our structural dimensional metrology laboratory, we implemented a setup to determine coefficients of thermal expansions (CTE) of ultra-stable materials at temperatures from 300 K down to 100 K. Such low CTE materials are important for dimensionally stable structures in space and terrestrial applications, e. g. to enable precise measurements. This CTE characterization is done in the 10 ppb/K (10·10-9 K-1) range by applying small temperature variation around dedicated absolute temperatures. In order to accommodate arbitrary sample materials, we bounce light off mirrors attached to the sample by custom mounts. The light and therefore the thermal-induced length variations is then analyzed by an interferometer with sub-nanometer sensitivity. Here, we present a more detailed investigation of a process during sample measurements using differential wavefront sensing (DWS)
JOKARUS - Design of a compact optical iodine frequency reference for a sounding rocket mission
We present the design of a compact absolute optical frequency reference for
space applications based on hyperfine transitions in molecular iodine with a
targeted fractional frequency instability of better than . It
is based on a micro-integrated extended cavity diode laser with integrated
optical amplifier, fiber pigtailed second harmonic generation wave-guide
modules, and a quasi-monolithic spectroscopy setup with operating electronics.
The instrument described here is scheduled for launch end of 2017 aboard the
TEXUS 54 sounding rocket as an important qualification step towards space
application of iodine frequency references and related technologies. The
payload will operate autonomously and its optical frequency will be compared to
an optical frequency comb during its space flight
BOOST -- A Satellite Mission to Test Lorentz Invariance Using High-Performance Optical Frequency References
BOOST (BOOst Symmetry Test) is a proposed satellite mission to search for
violations of Lorentz invariance by comparing two optical frequency references.
One is based on a long-term stable optical resonator and the other on a
hyperfine transition in molecular iodine. This mission will allow to determine
several parameters of the standard model extension in the electron sector up to
two orders of magnitude better than with the current best experiments. Here, we
will give an overview of the mission, the science case and the payload.Comment: 11 pages, 2 figures, accepted for publication in Phys. Rev.
Modern Michelson-Morley experiment using cryogenic optical resonators
We report on a new test of Lorentz invariance performed by comparing the
resonance frequencies of two orthogonal cryogenic optical resonators subject to
Earth's rotation over 1 year. For a possible anisotropy of the speed of light
c, we obtain 2.6 +/- 1.7 parts in 10^15. Within the Robertson-Mansouri-Sexl
test theory, this implies an isotropy violation parameter beta - delta - 1/2 of
-2.2 +/- 1.5 parts in 10^9, about three times lower than the best previous
result. Within the general extension of the standard model of particle physics,
we extract limits on 7 parameters at accuracies down to a part in 10^15,
improving the best previous result by about two orders of magnitude
Optical Technologies for Future Global Navigation Satellite Systems
Accurate, robust and reliable positioning and timing has become crucial for a wide spectrum of applications. New technologies will further improve the services offered by Global Navigation Satellite Systems (GNSSs). Optical technologies are promising candidates to achieve significant improvements in terms of accuracy, robustness and reliability of GNSSs in near future. First and foremost, optical inter-satellite links (OISLs) and optical clock technologies show enormous potential for future applications at the core of next generation GNSS architectures. Both technologies can be implemented independently from each other in current GNSS as the development lines may differ, in particular in terms of technology readiness. We will present different tracks on how optical key technologies could potentially be integrated in next generations of GNSS, and assess the corresponding improvements
Optomechanical resonator-enhanced atom interferometry
Matter-wave interferometry and spectroscopy of optomechanical resonators offer complementary advantages. Interferometry with cold atoms is employed for accurate and long-term stable measurements, yet it is challenged by its dynamic range and cyclic acquisition. Spectroscopy of optomechanical resonators features continuous signals with large dynamic range, however it is generally subject to drifts. In this work, we combine the advantages of both devices. Measuring the motion of a mirror and matter waves interferometrically with respect to a joint reference allows us to operate an atomic gravimeter in a seismically noisy environment otherwise inhibiting readout of its phase. Our method is applicable to a variety of quantum sensors and shows large potential for improvements of both elements by quantum engineering. © 2020, The Author(s)
The Bose-Einstein Condensate and Cold Atom Laboratory
© 2020, The Author(s). Microgravity eases several constraints limiting experiments with ultracold and condensed atoms on ground. It enables extended times of flight without suspension and eliminates the gravitational sag for trapped atoms. These advantages motivated numerous initiatives to adapt and operate experimental setups on microgravity platforms. We describe the design of the payload, motivations for design choices, and capabilities of the Bose-Einstein Condensate and Cold Atom Laboratory (BECCAL), a NASA-DLR collaboration. BECCAL builds on the heritage of previous devices operated in microgravity, features rubidium and potassium, multiple options for magnetic and optical trapping, different methods for coherent manipulation, and will offer new perspectives for experiments on quantum optics, atom optics, and atom interferometry in the unique microgravity environment on board the International Space Station
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