Showing papers on "Atom interferometer published in 2017"
TL;DR: This work uses a dual light-pulse atom interferometer as a gradiometer for precise gravitational measurements and measures a phase shift associated with tidal forces of spacetime curvature.
Abstract: Spacetime curvature induces tidal forces on the wave function of a single quantum system. Using a dual light-pulse atom interferometer, we measure a phase shift associated with such tidal forces. The macroscopic spatial superposition state in each interferometer (extending over 16 cm) acts as a nonlocal probe of the spacetime manifold. Additionally, we utilize the dual atom interferometer as a gradiometer for precise gravitational measurements.
224 citations
TL;DR: In this article, a Bragg atom interferometer in a gravity gradiometer configuration was used to compare the free fall of rubidium atoms prepared in two hyperfine states and in their coherent superposition.
Abstract: The Einstein equivalence principle (EEP) has a central role in the understanding of gravity and space-time. In its weak form, or weak equivalence principle (WEP), it directly implies equivalence between inertial and gravitational mass. Verifying this principle in a regime where the relevant properties of the test body must be described by quantum theory has profound implications. Here we report on a novel WEP test for atoms: a Bragg atom interferometer in a gravity gradiometer configuration compares the free fall of rubidium atoms prepared in two hyperfine states and in their coherent superposition. The use of the superposition state allows testing genuine quantum aspects of EEP with no classical analogue, which have remained completely unexplored so far. In addition, we measure the Eotvos ratio of atoms in two hyperfine levels with relative uncertainty in the low 10-9, improving previous results by almost two orders of magnitude.
178 citations
TL;DR: A matter-wave interferometer based on single-photon interaction on the ultranarrow optical clock transition of strontium atoms is realization and its operation as a gravimeter and as a gravity gradiometer is experimentally demonstrated.
Abstract: A single-photon interaction atom interferometer is demonstrated using the ultra-narrow optical clock transition of strontium atoms.
129 citations
TL;DR: This work presents a promising scheme that overcomes problems by compensating the effects of the gravity gradients and circumvents the fundamental limitations due to Heisenberg's uncertainty principle, and relaxes the experimental requirements on initial colocation by several orders of magnitude.
Abstract: Atom interferometry tests of universality of free fall based on the differential measurement of two different atomic species provide a useful complement to those based on macroscopic masses. However, when striving for the highest possible sensitivities, gravity gradients pose a serious challenge. Indeed, the relative initial position and velocity for the two species need to be controlled with extremely high accuracy, which can be rather demanding in practice and whose verification may require rather long integration times. Furthermore, in highly sensitive configurations gravity gradients lead to a drastic loss of contrast. These difficulties can be mitigated by employing wave packets with narrower position and momentum widths, but this is ultimately limited by Heisenberg's uncertainty principle. We present a promising scheme that overcomes these problems by compensating the effects of the gravity gradients and circumvents the fundamental limitations due to Heisenberg's uncertainty principle. Furthermore, it relaxes the experimental requirements on initial colocation by several orders of magnitude.
109 citations
TL;DR: In this article, an underground long baseline atom interferometer was used to study gravity at large scale, with a peak strain sensitivity of 2$\cdot 10−13/\sqrt{\mathrm{Hz}}$ at 2 Hz.
Abstract: We present an underground long baseline atom interferometer to study gravity at large scale. The hybrid atom-laser antenna will use several atom interferometers simultaneously interrogated by the resonant mode of an optical cavity. The instrument will be a demonstrator for gravitational wave detection in a frequency band (100 mHz - 1 Hz) not explored by classical ground and space-based observatories, and interesting for potential astrophysical sources. In the initial instrument configuration, standard atom interferometry techniques will be adopted, which will bring to a peak strain sensitivity of 2$\cdot 10^{-13}/\sqrt{\mathrm{Hz}}$ at 2 Hz. The experiment will be realized at the underground facility of the Laboratoire Souterrain a Bas Bruit (LSBB) in Rustrel--France, an exceptional site located away from major anthropogenic disturbances and showing very low background noise. In the following, we present the measurement principle of an in-cavity atom interferometer, derive signal extraction for Gravitational Wave measurement from the antenna and determine the expected strain sensitivity. We then detail the functioning of the different systems of the antenna and describe the properties of the installation site.
108 citations
20 Dec 2017
TL;DR: In this article, an atom interferometer measuring acceleration, rotation, and inclination by pointing Raman beams toward individual faces of a pyramidal mirror is demonstrated. But the method is not suitable for inertial sensing.
Abstract: Atom interferometry has become one of the most powerful technologies for precision measurements. To develop simple, precise, and versatile atom interferometers for inertial sensing, we demonstrate an atom interferometer measuring acceleration, rotation, and inclination by pointing Raman beams toward individual faces of a pyramidal mirror. Only a single-diode laser is used for all functions, including atom trapping, interferometry, and detection. Efficient Doppler-sensitive Raman transitions are achieved without velocity selecting the atom sample, and with zero differential AC Stark shift between the cesium hyperfine ground states, increasing signal-to-noise and suppressing systematic effects. We measure gravity along two axes (vertical and 45° to the vertical), rotation, and inclination with sensitivities of 6 μm/s2/Hz, 300 μrad/s/Hz, and 4 μrad/Hz, respectively. This work paves the way toward deployable multiaxis atom interferometers for geodesy, geology, or inertial navigation.
82 citations
TL;DR: A new method to exactly compensate the effects introduced by gravity gradients in a Raman-pulse atom interferometer is demonstrated and an improved scheme to determine the Newtonian gravitational constant G towards the 10 ppm relative uncertainty is proposed.
Abstract: A method is demonstrated that compensates for gravity gradients in Raman-pulse atom interferometers.
72 citations
TL;DR: The potential for atom interferometry based gravimetry is assessed, suggesting that the key opportunity resides within the development of gravity gradiometry sensors to enable drastic improvements in measurement time.
Abstract: The high precision and scalable technology offered by atom interferometry has the opportunity to profoundly affect gravity surveys, enabling the detection of features of either smaller size or grea...
61 citations
TL;DR: In this experiment, it is shown that clear interference signals may be obtained without laser cooling, and that multiple interferometers may be operated simultaneously by addressing multiple velocity classes.
Abstract: We demonstrate matter-wave interference in a warm vapor of rubidium atoms. Established approaches to light-pulse atom interferometry rely on laser cooling to concentrate a large ensemble of atoms into a velocity class resonant with the atom optical light pulse. In our experiment, we show that clear interference signals may be obtained without laser cooling. This effect relies on the Doppler selectivity of the atom interferometer resonance. This interferometer may be configured to measure accelerations, and we demonstrate that multiple interferometers may be operated simultaneously by addressing multiple velocity classes.
38 citations
TL;DR: In this article, a theoretical framework is developed to unify the mechanisms of atomic gravitational-wave detectors implemented as atomic clocks or as atom interferometers, and major enhancements to the sensitivity of the detectors using confined atoms are proposed thanks to the unified understanding.
Abstract: A theoretical framework is developed to unify the mechanisms of atomic gravitational-wave detectors implemented as atomic clocks or as atom interferometers. Major enhancements to the sensitivity of the detectors using confined atoms are proposed thanks to the unified understanding.
34 citations
TL;DR: The state of the art in the development of onboard gravity gradiometers used for mineral exploration and space missions is discussed in this article, where the results of their operation are analyzed and the potential applications of gravity gradient measurement for various applications are outlined.
Abstract: The state of the art in the development of onboard gravity gradiometers used for mineral exploration and space missions is discussed; the results of their operation are analyzed. Gradiometer designs using atom interferometry are considered. Prospects for the development of gravity gradiometry for various applications are outlined.
TL;DR: In this article, the authors present the technical realization of a compact system for performing experiments with cold 87Rb and 39K atoms in microgravity in the future, which fits into a capsule to be used in the drop tower Bremen.
Abstract: We present the technical realization of a compact system for performing experiments with cold 87Rb and 39K atoms in microgravity in the future. The whole system fits into a capsule to be used in the drop tower Bremen. One of the advantages of a microgravity environment is long time evolution of atomic clouds which yields higher sensitivities in atom interferometer measurements. We give a full description of the system containing an experimental chamber with ultra-high vacuum conditions, miniaturized laser systems, a high-power thulium-doped fiber laser, the electronics and the power management. In a two-stage magneto-optical trap atoms should be cooled to the low μK regime. The thulium-doped fiber laser will create an optical dipole trap which will allow further cooling to sub- μK temperatures. The presented system fulfills the demanding requirements on size and power management for cold atom experiments on a microgravity platform, especially with respect to the use of an optical dipole trap. A first test in microgravity, including the creation of a cold Rb ensemble, shows the functionality of the system.
TL;DR: In this paper, a deformable mirror is used to control the laser wavefronts in atom interferometry to correct the wavefront aberrations in an atomic gravimeter.
Abstract: Wavefront aberrations are identified as a major limitation in quantum sensors. They are today the main contribution in the uncertainty budget of best cold atom interferometers based on two-photon laser beam splitters, and constitute an important limit for their long-term stability, impeding these instruments from reaching their full potential. Moreover, they will also remain a major obstacle in future experiments based on large momentum beam splitters. In this article, we tackle this issue by using a deformable mirror to control actively the laser wavefronts in atom interferometry. In particular, we demonstrate in an experimental proof of principle the efficient correction of wavefront aberrations in an atomic gravimeter.
TL;DR: In this paper, a deformable mirror is used to control the laser wave fronts in a cold-atom gravimeter, compensating for the distortions induced by optical elements, which opens perspectives for atom interferometry, with applications in navigation, space physics, and high-precision metrology.
Abstract: Optical aberrations in light-pulse atom interferometers are a major limitation in the accuracy and stability of these quantum sensors. In a proof-of-principle experiment, the authors use a deformable mirror to actively control the laser wave fronts in a cold-atom gravimeter, compensating for the distortions induced by optical elements. This fine control of wave fronts opens perspectives for atom interferometry, with applications in navigation, space physics, and high-precision metrology.
TL;DR: Shaken lattice interferometry with atoms trapped in a one-dimensional optical lattice is introduced in this paper.By phase modulating (shaking) the lattice, the authors control the momentum state of the atoms.
Abstract: We introduce shaken lattice interferometry with atoms trapped in a one-dimensional optical lattice. By phase modulating (shaking) the lattice, we control the momentum state of the atoms. Through a sequence of shaking functions, the atoms undergo an interferometer sequence of splitting, propagation, reflection, reverse propagation, and recombination. Each shaking function in the sequence is optimized with a genetic algorithm to achieve the desired momentum state transitions. As with conventional atom interferometers, the sensitivity of the shaken lattice interferometer increases with interrogation time. The shaken lattice interferometer may also be optimized to sense signals of interest while rejecting others, such as the measurement of an ac inertial signal in the presence of an unwanted dc signal.
Journal Article•
TL;DR: In this article, a single-source dual atom interferometer was used as a gradiometer for precise gravitational measurements, achieving a resolution of 3 × 10−9 s−2 per shot and measuring a 1 rad phase shift induced by the source mass.
Abstract: We present a single-source dual atom interferometer and utilize it as a gradiometer for precise gravitational measurements. The macroscopic separation between interfering atomic wave packets (as large as 16 cm) reveals the interplay of recoil effects and gravitational curvature from a nearby Pb source mass. The gradiometer baseline is set by the laser wavelength and pulse timings, which can be measured to high precision. Using a long drift time and large momentum transfer atom optics, the gradiometer reaches a resolution of 3 × 10−9 s−2 per shot and measures a 1 rad phase shift induced by the source mass.
TL;DR: An observation ruling out the possibility of a purely mixed state at the input of the interferometer is reported, and it is explained how the current setup can be extended to enable a test of a Bell inequality on momentum observables.
Abstract: We present a free-space interferometer to observe two-particle interference of a pair of atoms with entangled momenta. The source of atom pairs is a Bose-Einstein condensate subject to a dynamical instability, and the interferometer is realized using Bragg diffraction on optical lattices, in the spirit of our recent Hong-Ou-Mandel experiment. We report on an observation ruling out the possibility of a purely mixed state at the input of the interferometer. We explain how our current setup can be extended to enable a test of a Bell inequality on momentum observables.
TL;DR: In this paper, a marginally stable optical resonator suitable for atom interferometry is proposed, which is based on two flat mirrors at the focal planes of a lens that produces the large beam waist required to coherently manipulate cold atomic ensembles.
Abstract: We propose a marginally stable optical resonator suitable for atom interferometry. The resonator geometry is based on two flat mirrors at the focal planes of a lens that produces the large beam waist required to coherently manipulate cold atomic ensembles. Optical gains of about 100 are achievable using optics with part-per-thousand losses. The resulting power build-up will allow for enhanced coherent manipulation of the atomic wavepackets such as large separation beamsplitters. We study the effect of longitudinal misalignments and assess the robustness of the resonator in terms of intensity and phase profiles of the intra-cavity field. We also study how to implement atom interferometry based on Large Momentum Transfer Bragg diffraction in such a cavity.
TL;DR: In this paper, a marginally stable optical resonator suitable for atom interferometry is proposed, which is based on two flat mirrors at the focal planes of a lens that produces the large beam waist required to coherently manipulate cold atomic ensembles.
Abstract: We propose a marginally stable optical resonator suitable for atom interferometry. The resonator geometry is based on two flat mirrors at the focal planes of a lens that produces the large beam waist required to coherently manipulate cold atomic ensembles. Optical gains of about 100 are achievable using optics with part-per-thousand losses. The resulting power build-up will allow for enhanced coherent manipulation of the atomic wavepackets such as large separation beamsplitters. We study the effect of longitudinal misalignments and assess the robustness of the resonator in terms of intensity and phase profiles of the intra-cavity field. We also study how to implement atom interferometry based on Large Momentum Transfer Bragg diffraction in such a cavity.
TL;DR: An atom interferometer serves as a sensitive tiltmeter that can measure Earth's tidal deformations as mentioned in this paper, which can be used as a tiltometer for detecting Earth's ocean currents.
Abstract: An atom interferometer serves as a sensitive tiltmeter that can measure Earth's tidal deformations.
TL;DR: In this article, a vectorial expression for the relativistic interferometric phase shift in an atom interferometer is given, where both the atoms and the light are treated relativistically.
Abstract: Atom interferometry is currently developing rapidly, which is now reaching sufficient precision to motivate laboratory tests of general relativity. Thus, it is extremely significant to develop a general relativistic model for atom interferometers. In this paper, we mainly present an analytical derivation process and first give a complete vectorial expression for the relativistic interferometric phase shift in an atom interferometer. The dynamics of the interferometer are studied, where both the atoms and the light are treated relativistically. Then, an appropriate coordinate transformation for the light is performed crucially to simplify the calculation. In addition, the Bord\'e $ABCD$ matrix combined with quantum mechanics and the ``perturbation'' approach are applied to make a methodical calculation for the total phase shift. Finally, we derive the relativistic phase shift kept up to a sensitivity of the acceleration $\ensuremath{\sim}1{0}^{\ensuremath{-}14}\text{ }\text{ }{\mathrm{m}/\mathrm{s}}^{2}$ for a $10\text{\ensuremath{-}}\mathrm{m}$-long atom interferometer.
TL;DR: In this paper, the authors showed a CCA interferometer with caesium atoms loaded horizontally into a vertical 40 cm cavity, which placed a tight constraint on the measurement time, which was just 20 ms.
Abstract: Atom interferometry inside an optical cavity was demonstrated in Hamilton et al. (Phys Rev Lett 114:100405, 2015 [1]), where they show a \(\pi /2-\pi -\pi /2\) interferometer with caesium atoms loaded horizontally into a vertical 40 cm cavity (Fig. 6.1). In this proof of principle experiment, the small cavity mode volume placed a tight constraint on the total measurement time, which was just 20 ms.
TL;DR: In this article, a sloshing-Sagnac interferometer was proposed to provide improved quantum noise limited sensitivity and lower coating thermal noise than standard position meter interferometers employed in current gravitational wave detectors.
Abstract: Speedmeters are known to be quantum non-demolition devices and, by potentially providing sensitivity beyond the standard quantum limit, become interesting for third generation gravitational wave detectors. Here we introduce a new configuration, the sloshing-Sagnac interferometer, and compare it to the more established ring-Sagnac interferometer. The sloshing-Sagnac interferometer is designed to provide improved quantum noise limited sensitivity and lower coating thermal noise than standard position meter interferometers employed in current gravitational wave detectors. We compare the quantum noise limited sensitivity of the ring-Sagnac and the sloshing-Sagnac interferometers, in the frequency range, from 5 Hz to 100 Hz, where they provide the greatest potential benefit. We evaluate the improvement in terms of the unweighted noise reduction below the standard quantum limit, and by finding the range up to which binary black hole inspirals may be observed. The sloshing-Sagnac was found to give approximately similar or better sensitivity than the ring-Sagnac in all cases. We also show that by eliminating the requirement for maximally-reflecting cavity end mirrors with correspondingly-thick multi-layer coatings, coating noise can be reduced by a factor of approximately 2.2 compared to conventional interferometers.
TL;DR: In this paper, an atom interferometer measuring acceleration, rotation, and inclination by pointing Raman beams toward individual faces of a pyramidal mirror is demonstrated. But the method is not suitable for inertial sensing, and it cannot be used for geodesy, geology, or inertial navigation.
Abstract: Atom interferometry has become one of the most powerful technologies for precision measurements. To develop simple, precise, and versatile atom interferometers for inertial sensing, we demonstrate an atom interferometer measuring acceleration, rotation, and inclination by pointing Raman beams toward individual faces of a pyramidal mirror. Only a single diode laser is used for all functions, including atom trapping, interferometry, and detection. Efficient Doppler-sensitive Raman transitions are achieved without the velocity selecting the atom sample, and with zero differential AC Stark shift between the cesium hyperfine ground states, increasing signal-to-noise and suppressing systematic effects. We measure gravity along two axes (vertical and 45$^\circ$ to the vertical), rotation, and inclination with sensitivities of 6$\,\mu$m/s$^2/\sqrt{\rm Hz}$, 300$\,\mu$rad/s/$\sqrt{\rm Hz}$, and 4$\,\mu$rad/$\sqrt{\rm Hz}$, respectively. This work paves the way toward deployable multiaxis atom interferometers for geodesy, geology, or inertial navigation.
TL;DR: In this paper, a compact and robust frequency-doubled telecom laser system at 780 nm is presented for a rubidium cold atom interferometer using optical lattices, which adopts an optical switch at 1.5 µm and a dual-wavelength second harmonic generation system.
01 Sep 2017
TL;DR: In this paper, the authors used spin exchange in a Bose-Einstein condensate to generate a non-classical state and then matched second period of spin exchange is performed that nonlinearly amplifies the output signal and maps the phase onto readily detectable first moments.
Abstract: Active interferometers use amplifying elements for beam splitting and recombination. We experimentally implement such a device by using spin exchange in a Bose–Einstein condensate. The two interferometry modes are initially empty spin states that get spontaneously populated in the process of parametric amplification. This nonlinear mechanism scatters atoms into both modes in a pairwise fashion and generates a non-classical state. Finally, a matched second period of spin exchange is performed that nonlinearly amplifies the output signal and maps the phase onto readily detectable first moments. Depending on the accumulated phase this nonlinear readout can reverse the initial dynamics and deamplify the entangled state back to empty spin states. This sequence is described in the framework of SU(1,1) mode transformations and compared to the SU(2) angular momentum description of passive interferometers.
TL;DR: In this article, the influence of temporally shaping the light pulses in an atom interferometer, with a focus on the phase response of the interferometers, was studied theoretically and experimentally, and the trade-offs to operate when choosing a particular pulse shape, by taking into account phase noise rejection, velocity selectivity, and applicability to large momentum transfer atom interFERometry.
Abstract: We study theoretically and experimentally the influence of temporally shaping the light pulses in an atom interferometer, with a focus on the phase response of the interferometer. We show that smooth light pulse shapes allow rejecting high frequency phase fluctuations (above the Rabi frequency) and thus relax the requirements on the phase noise or frequency noise of the interrogation lasers driving the interferometer. The light pulse shape is also shown to modify the scale factor of the interferometer, which has to be taken into account in the evaluation of its accuracy budget. We discuss the trade-offs to operate when choosing a particular pulse shape, by taking into account phase noise rejection, velocity selectivity, and applicability to large momentum transfer atom interferometry.
TL;DR: In this article, the authors proposed a novel experimental setup for measuring the Newtonian gravity constant with a relative accuracy of $10^{-5}$ using a standard cold atomic fountain and matter wave interferometry.
Abstract: In precision metrology the determination of the Newtonian gravity constant $G$ represents a real problem, since its history is plagued by huge unknown discrepancies between a large number of independent experiments. In this paper we propose a novel experimental setup for measuring $G$ with a relative accuracy of $10^{-5}$ using a standard cold atomic fountain and matter wave interferometry. We discuss in details the major sources of systematic errors, providing also the expected statistical uncertainty. Feasibility of determining $G$ at a level of $10^{-6}$ level is also discussed.
TL;DR: In this article, a dual-species atom accelerometer manipulating simultaneously both isotopes of rubidium was used to deduce inertial measurements, and the authors reported a preliminary experimental realization of original concepts involving the implementation of two atom interferometers first with different interrogation times and secondly in phase quadrature.
Abstract: In the field of cold atom inertial sensors, we present and analyze innovative configurations for improving their measurement range and sensitivity, especially attracting for onboard applications. These configurations rely on multi-species atom interferometry, involving the simultaneous manipulation of different atomic species in a unique instrument to deduce inertial measurements. Using a dual-species atom accelerometer manipulating simultaneously both isotopes of rubidium, we report a preliminary experimental realization of original concepts involving the implementation of two atom interferometers first with different interrogation times and secondly in phase quadrature. These results open the door to a new generation of atomic sensors relying on high performance multi-species atom interferometric measurements.
TL;DR: In this paper, an atom interferometer operating on the 1S0-3P0 clock transition of 87Sr atoms in a "magic" optical guide is demonstrated, where the light shift perturbations of the guiding potential are canceled.
Abstract: We demonstrate an atom interferometer operating on the 1S0–3P0 clock transition of 87Sr atoms in a "magic" optical guide, where the light shift perturbations of the guiding potential are canceled. As a proof-of-principle demonstration, a Mach–Zehnder interferometer is set horizontally to map the acceleration introduced by the focused optical guide. This magic guide interferometer on the clock transition is applicable to atomic elements where magic wavelengths can be found. Possible applications of the magic guide interferometer, including a hollow-core fiber interferometer and gradiometer, are discussed.