Download or read book Modelling Light pulse Atom Interferometry for Precision Measurements written by Jens Jenewein and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atom Interferometry written by Guglielmo M. Tino and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since atom interferometers were first realized about 20 years ago, atom interferometry has had many applications in basic and applied science, and has been used to measure gravity acceleration, rotations and fundamental physical quantities with unprecedented precision. Future applications range from tests of general relativity to the development of next-generation inertial navigation systems. This book presents the lectures and notes from the Enrico Fermi school "Atom Interferometry", held in Varenna, Italy, in July 2013. The aim of the school was to cover basic experimental and theoretical aspects and to provide an updated review of current activities in the field as well as main achievements, open issues and future prospects. Topics covered include theoretical background and experimental schemes for atom interferometry; ultracold atoms and atom optics; comparison of atom, light, electron and neutron interferometers and their applications; high precision measurements with atom interferometry and their application to tests of fundamental physics, gravitation, inertial measurements and geophysics; measurement of fundamental constants; interferometry with quantum degenerate gases; matter wave interferometry beyond classical limits; large area interferometers; atom interferometry on chips; and interferometry with molecules.The book will be a valuable source of reference for students, newcomers and experts in the field of atom interferometry.
Download or read book Atom Interferometry Using Near Resonant Standing Waves of Light written by Peter Digby McDowall and published by . This book was released on 2013 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis details the experimental investigation of a new type of atom interferometer using rubidium-85 atoms in the unexplored near-resonant domain. A cold cloud of atoms, all prepared in the same hyperfine ground state, are subjected to temporally periodic pulses of near-resonant standing waves of light. The standing wave pulses are made to act like an absorption grating where only atoms located around the low intensity region about the nodes remain in the initial ground state, the rest are pumped into a dark hyperfine ground state. The output of the atom interferometer is a measure of the fraction of atoms remaining in the initial ground state after N standing wave pulses for different times between the pulses. An increased survival rate is observed for certain times between pulses due to the occurrence of a coherence echo and the matter wave Talbot effect. This feature allows us to use our atom interferometer to make measurements of the Talbot time which is an important parameter in determinations of the fine structure constant alpha. We provide a theoretical model to describe the relevant physics behind our atom interferometer that compares well with our empirical results. Design and implementation of the apparatus are discussed along with characterisation of parameters such as pulse duration, pulse number, and frequency. Finally we include a demonstration of how, in principle, our atom interferometer could be used to make precision measurements of the Talbot time along with some of the necessary steps to bring it in line with current leading measurements.
Download or read book Timekeeping and Accelerometry with Robust Light Pulse Atom Interferometers written by Krish Kotru and published by . This book was released on 2015 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light pulse atom interferometry (LPAI) is a powerful technique for precision measurements of inertial forces and time. Laboratory LPAI systems currently achieve state-ofthe- art acceleration sensitivity and establish the international atomic time standard. However, the realization of practical LPAI in dynamic environments (e.g., rapidly accelerating or rotating platforms) has been limited in part by atom optics-the analogues to optical beamsplitters and mirrors. Atom optics in traditional LPAIs are composed of resonant laser pulses that are susceptible to variations in optical detuning and intensity expected in sensors designed for dynamic environments. This thesis investigates atom optics that use frequency- and intensity-modulated laser pulses to suppress sensitivity to these inhomogeneities. For atomic timekeeping applications, a Ramsey LPAI sequence based on stimulated Raman transitions and frequency-swept adiabatic rapid passage (ARP) was developed. Raman ARP drives coherent transfer in an effective two-level atomic system by sweeping the Raman detuning through the two-photon resonance. In experiments with 133Cs atoms, Raman ARP reduced the sensitivity of Ramsey sequences to differential AC Stark shifts by about two orders of magnitude, relative to standard Raman transitions. Raman ARP also preserved fringe contrast despite substantial intensity inhomogeneity. The fractional frequency uncertainty of the ARP Ramsey sequence was limited by second-order Zeeman shifts to ~3.5 x 10-12 after about 2500 s of averaging. For accelerometry applications, Raman ARP provided efficient, large momentum transfer (LMT) atom optics in an acceleration-sensitive LPAI. These atom optics produced momentum splittings of up to 30 photon recoil momenta between interfering wavepackets-the largest to date for Raman atom optics. This splitting, in principle, enables up to a factor-of-15 improvement in sensitivity over the nominal interferometer. By forgoing cooling methods that reduce atom number, this LMT method reduces the measurement uncertainty due to atom shot-noise and enables large area atom interferometry at higher data-rates. These features could prove useful for fielded inertial sensors based on atom interferometry.
Download or read book Long time Atom Interferometry for Precision Tests of Fundamental Physics written by Susannah Moore Dickerson and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Light-pulse atom interferometry is a technique that is exquisitely sensitive to inertial forces. As such, it has exciting applications both in fundamental physics for precision tests of gravity, electrodynamics and quantum mechanics, as well as in practical situations for inertial navigation, geodesy, and timekeeping. In this work, I describe a 10 meter atomic fountain, designed for a precision test of the weak equivalence principle but with additional relevance in bounding proposed modifications of quantum mechanics, directly measuring general relativistic corrections, and detecting gravitational waves. This system is demonstrated to have the largest acceleration sensitivity to date by two orders of magnitude (6.7e-12 g). I also present precision measurements of Earth's rotation, the preparation of ultracold clouds to picokelvin effective temperatures, and current work to further improve the acceleration sensitivity through meter-scale separation between two halves of the atomic wavepacket. I close with a discussion of the next step towards an equivalence principle test: the creation of a well-overlapped, dual-species ultracold cloud.
Download or read book Clock Atom Interferometry for Precision Measurements in Fundamental Physics written by Thomas Frederick Wilkason and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent technological advances have enabled the development of new precision atomic sensors for tests of fundamental physics. In this thesis, I will introduce the concept of clock atom interferometry, a hybrid of atomic clocks and atom interferometry that is particularly suited for gravitational wave detection and ultralight dark matter searches. I outline the experiment we built to cool and trap strontium atoms for prototyping this concept and demonstrating our initial atom interferometric results. I will then discuss the first realization of large momentum transfer (LMT) clock atom interferometry using single-photon interactions on the strontium 689 nm transition, implementing Mach-Zehnder interferometers and gradiometers with state-of-the-art momentum separation to enhance their sensitivity. Furthermore, using amplitude modulated pulses, I demonstrate Floquet atom optics as a tool to allow symmetric evolution of two states at equal and opposite detuning and allows high pulse efficiencies greater than 99% for all detunings, in particular even when the detuning is on the order of the Rabi frequency. Applying this technique, I extend the visibility of an atom interferometer out to a record momentum transfer in excess of 400 photon momenta. I conclude by demonstrating how this technique can be further advanced to allow for 601 photon momenta of separation, as well as a discussion of the new measurement opportunities made possible with these techniques in the fields of high-precision inertial sensing and fundamental physics detection.
Download or read book Atom Interferometric Experiments with Bose Einstein Condensates in Microgravity written by Julia Pahl and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Englische Version: Light-pulse atom interferometry (AI) is an important tool for high precision measurements in the fields of inertial sensing or fundamental physics. Especially in combination with ultra-cold atomic sources and operation in microgravity, high sensitivities are expected that are necessary for the search for violations of the weak equivalence principle. QUANTUS-2 is a mobile atom interferometer operating at the ZARM drop tower in Bremen. With its high-flux, atom chip-based atomic rubidium source, it serves as a pathfinder for future space missions, examining key technologies like the generation of Bose-Einstein condensates (BECs), implementation of delta-kick collimation or application of various AI geometries. In this thesis, a potassium diode laser system has been built to complete the preordained functionality of dual-species operation. Based on the design of the rubidium laser system with micro-integrated laser diode modules and compact electronics, it successfully passed the qualification tests. In a proof of principle measurement, a potassium magneto-optical trap could be generated to prove the system's capability of trapping atoms. With rubidium, open Ramsey type interferometers and Mach-Zehnder interferometers (MZIs) were examined on ground and in over 155 drops in microgravity. The combination of variably delta-kicked collimated BECs and AI in microgravity revealed a new technique to determine the magnetic lens duration for optimal collimation. Asymmetric MZIs with interferometry times of 2T > 1s have successfully been demonstrated. Gravimetric examinations on ground with MZIs and by an additional levitation technique have been performed to determine the local gravitational acceleration g. The examined key technologies are fundamental necessities that have to be considered to pave the way for future space missions.
Download or read book Precision Measurement in Atom Interferometry Using Bragg Diffraction written by Brian Vincent Estey and published by . This book was released on 2016 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: We experimentally and theoretically study Bragg diffraction as a tool for large-momentum transfer beam splitters in atom interferometry. A theoretical framework is developed to quantify the diffraction phase systematic caused by Bragg diffraction and experiments are performed to confirm these predictions using a Ramsey-Bord\'e atom interferometer. We then develop methods to systematically cancel and reduce the diffraction phase systematic by carefully selecting Bragg diffraction parameters and utilizing Bloch oscillations. These techniques are then applied to an ongoing precision measurement of $h/m_\text{Cs}$ for cesium, with the end goal of measuring the fine structure constant $\alpha$. We demonstrate a high contrast simultaneous conjugate Ramsey-Bord\'e interferometer using 5th order Bragg diffraction and 25 common mode Bloch oscillations which achieves $2.5\times 10^6$ radians of phase. We also demonstrate an interferometer with a statistical uncertainty of $\delta \alpha/\alpha=0.25$ ppb after 25 hours of integration time that has diffraction phase systematic error of around 1 ppb. Other sources of systematic uncertainty are also thoroughly explored and determined to better than 0.1 ppb. The techniques and theories developed in this thesis will hopefully help enable future precision measurements based on Bragg diffraction.
Download or read book New Techniques for Precision Atom Interferometry and Applications to Fundamental Tests of Gravity and of Quantum Mechanics written by Tim Kovachy and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Light-pulse atom interferometry--in which quantum mechanical atomic wave packets are split along two paths and later recombined and made to interfere by sequences of optical pulses--is a remarkably sensitive technique for measuring inertial forces, allowing it to be a valuable tool for applications ranging from fundamental tests of gravity to geodesy and inertial navigation. The inertial sensitivity of an atom interferometer is proportional to its enclosed spacetime area--that is, the product of the spatial separation between the two interferometer paths and the interferometer duration. Therefore, new techniques that allow this spacetime area to be increased are essential in order for atom interferometry to reach its full potential. In this thesis, I describe the development of such techniques. We approach the problem of increasing the interferometer spacetime area on two fronts. First, we implement new methods to increase the momentum transferred by the beam splitters of the interferometer. The velocity difference and therefore the spatial separation of the interferometer paths are proportional to this momentum transfer. Conventional atom optics techniques involve beam splitters that transfer two photon momentum recoils (2 hbar k) to the atoms. I will discuss our realization of large momentum transfer (LMT) beam splitters that transfer up to 100 hbar k. Second, we have built a 10 m tall atomic fountain that allows the total interferometer duration to be increased to 2 s. Ultimately, we combined LMT atom optics with long-duration atom interferometry in the 10 m atomic fountain, leading to very large spacetime area atom interferometers. In these very large area atom interferometers, the separation between the two atomic wave packets that respectively travel along the two interferometer paths reaches distances of up to 54 cm. Therefore, in addition to offering greatly increased inertial sensitivity, these interferometers probe the quantum mechanical wavelike nature of matter in a new macroscopic regime. I will discuss the techniques we devised to overcome the many technical challenges associated with such interferometers, which in other apparatus have prevented interference from being maintained for path separations larger than 1 cm. I will also describe initial results from the use of our very large area interferometers to test the equivalence principle with Rb-85 and Rb-87 and our plans for further progress in this direction. Very large area atom interferometry requires high laser power and extremely cold atom sources. We have developed a novel high power, frequency doubled laser source at 780 nm that is suitable for atom optics. Also, we have implemented a sequence of matter wave lenses to prepare and measure atomic ensembles with record-low effective temperatures of 50 pK. In addition to applications in atom interferometry, we expect that such an atom source will be broadly useful for a wide range of experiments.
Download or read book Hot Beats and Tune Outs written by Kayleigh Cassella and published by . This book was released on 2018 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ushered forth by advances in time and frequency metrology, atom interferometry remains an indispensable measurement tool in atomic physics due to its precision and versatility. A sequence of four $\pi/2$ beam splitter pulses can create either an interferometer sensitive to the atom's recoil frequency when the momentum imparted by the light reverses direction between pulse pairs or, when constructed from pulses without such reversal, sensitive to the perturbing potential from an external optical field. Here, we demonstrate the first atom interferometer with laser-cooled lithium, advantageous for its low mass and simple atomic structure. We study both a recoil-sensitive Ramsey-Bord\'e interferometer and interferometry sensitive to the dynamic polarizability of the ground state of lithium. Recoil-sensitive Ramsey-Bord\'e interferometry benefits from lithium's high recoil frequency, a consequence of its low mass. At an interrogation time of 10 ms, a Ramsey-Bord\'e lithium interferometer could achieve sensitivities comparable to those realized at much longer times with heavier alkali atoms. However, in contrast with other atoms that are used for atom interferometry, lithium's unresolved excited-state hyperfine structure precludes the the cycling transition necessary for efficient cooling. Without sub-Doppler cooling techniques. As as result, a lithium atomic gas is typically laser cooled to temperatures around 300 $\mu$K, above the Doppler limit, and well above the recoil temperature of 6 $\mu$K. This higher temperature gas expands rapidly during the operation of an atom interferometer, limiting the experimental interrogation time and preventing spatially resolved detection. In this work, a light-pulse lithium matter-wave interferometer is demonstrated in spite of these limitation. Two-photon Raman interferometer pulses coherently couple the atom's spin and momentum and are thus able to spectrally resolve the outputs. These fast pulses drive conjugate interferometers simultaneously which beat with a fast frequency component proportional to the atomic recoil frequency and an envelope modulated by the two-photon detuning of the Raman transition. We detect the summed signal at short experimental times, preventing perturbation of the signal from vibration noise. This demonstration of a sub-recoil measurement with a super-recoil sample opens the door to similar scheme with other particles that are difficult to trap and cool well, like electrons. An interferometer instead composed of $\pi/2$-pulses with a single direction of momentum transfer, can be sensitive to the dynamic polarizability of the atomic ground state. By scanning the frequency of an external driving field, such a measurement can be used to determine the atom's tune-out wavelength. This is the wavelength at which the frequency-dependent polarizability vanishes due to compensating ac-Stark shifts from other atomic states. Lithium's simple atomic structure allows for a precise computation of properties with only {\em ab initio} wave functions and spectroscopic data. A direct interferometric measurement of lithium's red tune-out wavelength at 670.971626(1) nm, is a precise comparison to existing `all-order' atomic theory computations. It also provides another way to experimentally determine the $S-$ to $P-$ transitions matrix elements, for which large correlations and small values complicate computations. Finally, a future measurement of lithium's ultraviolet tune-out wavelength of at 324.192(2) nm would be sensitive to relativistic approximations in the atomic structure description. Atom interferometry simultaneously verifies existing atomic theory with measurements of atomic properties and searches for exotic physics lurking in plain sight. The techniques developed here broaden the applicability of interferometry and increase measurement sensitivity by simplifying cooling, increasing atom number and reducing the cycle time. Overcoming the current experimental limitations on interrogation time would allow for ultra-precise measurements of both the tune-out wavelength and the fine structure constant.
Download or read book Long Baseline Atom Interferometry written by David Marvin Slaughter Johnson and published by Stanford University. This book was released on 2011 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to its impressive sensitivity, long baseline atom interferometry is an exciting tool for tests of fundamental physics. We are currently constructing a 10-meter scale apparatus to test the Weak Equivalence Principle (WEP) using co-located Rb85 and Rb87 atom interferometers. This apparatus aims to improve the current limit on WEP violation 100-fold, which illustrates the power of this technique. This scientific goal sets stringent requirements on the kinematic preparation of the atomic test masses, the interferometer laser wavefront and stability, as well as the electromagnetic and gravitational field homogeneity of the interferometer region. The efforts to control these sources of systematic error are discussed. Additionally, applications of long baseline atom interferometry to space-based sensors for geodesy and gravitational wave detection are presented.
Download or read book Single shot Holographic Readout of an Atom Interferometer written by Andrew Rae MacKellar and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atom interferometry is a precision measurement technique that encodes information in the phase of atomic wavefunctions, using matter-wave interference to project the encoded phase information onto some relatively easy-to-measure property at the interferometer output, like the fractional atomic population in a specific momentum or internal state. Atoms are perturbed by influences to which photons are insensitive, offering atom interferometers excellent sensitivity and access to physics outwith the range of conventional optical interferometers. As such, for probing of fundamental physics such as QED corrections, atoms are an obvious test bed. The primary focus of this thesis is the construction and development of an atom interferometer capable of performing single-shot measurements of the fine-structure constant using a holographic readout technique. This achievement allows the holographic interferometer an increased data acquisition rate on the order of 700-times that [sic] a conventional configuration. As an interfering medium we use a Bose-Einstein condensate containing around ~10[to the power of]5 87Rb atoms. We coherently manipulate the momentum of these atoms with the scattering of photons from an optical lattice with fully controllable intensity. We have developed a numerical toolbox capable of calculating optical-lattice pulse-sequences to generate arbitrary atom-optical operations such as mirrors, and beam-splitters, experimentally demonstrated with an efficiency of 99:97±0:03%. We have used these atom optics to create experimental atom interferometers with various applications, shown here in the cases of a magnetic gradiometer and in measurements of recoil frequency. This latter configuration has been used to perform a measurement of the fine-structure constant with a fractional uncertainty of 6500 ppm in a single shot, with a clear pathway to reduce this uncertainty to 2300 ppm per shot, whilst the increased speed of the holographic interferometer allows a corresponding reduction in uncertainty to 60 ppm within a twelve hour integration period.
Download or read book Interferometry and Precision Measurements with Bose condensed Atoms written by Daniel Doering and published by . This book was released on 2011 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bose-Einstein condensates are coherent matter waves, produced by cooling gaseous atomic clouds to ultra-low temperatures. For applications in atom interferometry and precision measurements, Bose-condensed sources present an intriguing alternative to thermal atoms. Although the current sensitivity achievable with interferometers using coherent atoms is not comparable to thermal beam machines (mainly due to the lower flux), there are promising ways to utilise the potential of Bose-condensed sources for atom interferometry. Among those is the low momentum width of Bose-Einstein condensates, which can generally be well controlled and is advantageous for increased interferometric sensitivities by implementing large momentum transfer beam splitters. As part of this thesis, experimental and theoretical investigations are presented to investigate the potential of Bose-Einstein condensates for such applications. We shall present the quantum projection noise limited performance of a Ramsey interferometer operating on the atomic clock transition of a freely expanding cloud of Bose-condensed rubidium 87 atoms. The results include Ramsey fringes of high visibility, not measurably affected by atomic interaction-induced dephasing effects. The achievement and detection of the quantum projection noise limit rely critically on the precision and accuracy of both the imaging setup and the coupling scheme in the interferometric beam splitters. The stabilisation of the beam splitters via an optical Sagnac interferometer is the basis for the quantum projection noise limited performance of the interferometer presented. For an increase of bandwidth and flux in atom interferometric measurements, it is advantageous to use a continuous atomic beam. A truly continuous coherent atom source has not been realised to date, and we present results on a pumping mechanism in this thesis, as a decisive step towards a continuous atom laser. By the investigation of different momentum resonances, we find that the pumping scheme relies on a Raman superradiance-like process. Finally, the thesis demonstrates two interaction measurements in rubidium. The strong mean field interactions due to the high densities in Bose-Einstein condensates are used to probe the potential of a rubidium 87 condensate with an atom laser. The measurement allows a determination of the scattering length between the two atomic states involved. In addition to this two-body scattering scheme, we present a measurement of three-body loss coefficients, extracted from loss curves in rubidium 85 Bose-Einstein condensates. The measurement provides new upper bounds on the three-body loss coefficients at the scattering lengths considered.
Download or read book A Precision Measurement of the Photon Recoil Using Large Area Atom Interferometry written by Sheng-wey Chiow and published by . This book was released on 2008 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on progress of a precision measurement of the photon recoil of a cesium atom using atom interferometers consisting of multi-photon beamsplitters. We present large area atom interferometers with up to 24-photon Bragg diffraction as beamsplitters, which increase the phase shift 12-fold for the Mach-Zehnder geometry and 144-fold for the Ramsey-Borde geometry. Fringe visibilities as high as 52% in the Mach-Zehnder geometry and 36% (72% of the theoretical optimum) in the Ramsey-Borde geometry with 12h k-momentum-transfer beamsplitters are presented. The decrease of visibility at pulse separation time longer than 10 ms is mostly ascribed to residual vibrational noise.
Download or read book Light Pulse Atom Interferometry at Short Interrogation Times for Inertial Navigation written by David LaGrange Butts and published by . This book was released on 2012 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light pulse atom interferometry with cold atoms is a promising inertial sensing technology for high accuracy navigation. At present, laboratory atom interferometers match or surpass state of the art mechanical and optical inertial sensors in terms of sensitivity and long term stability. Conventional laboratory systems, however, do not achieve sufficient bandwidth or dynamic range to operate in a dynamic environment; furthermore, the size, weight and power of laboratory sensors are unsuitable for many applications. In this thesis, atom interferometry is realized at shorter interrogation times (15 ms as opposed to 100 ms), in which the required sensitivity, bandwidth and dynamic range of navigation systems becomes feasible. A cold atom gravimeter testbed using atom interferometry with stimulated Raman transitions was developed, which executed the entire measurement cycle in a compact vacuum cell (~ ~ 80 cc). The system demonstrated an inferred sensitivity of 2 [mu]g[square root] Hz for an interrogation time of 2T = 10 ms (based on measured phase SNR, scale factor, and repetition rate). With realistic improvements to the apparatus, it could achieve a sensitivity of
Download or read book Atom Optics and Space Physics written by E. Arimondo and published by IOS Press. This book was released on 2009 with total page 519 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The goal of this volume is to discuss the rapidly moving field of atom optics and interferometry with all its intricate aspects ranging from fundamental physics to applications and the theory of relativity. The breathtaking success in manipulating atoms using lasers has encouraged these two so far disjunct communities to move closer together and begin collaborations. After an introduction to atom optics and Bose-Einstein condensation, the theoretical foundations of cold atom interferometers, their use to test gravity, and their implementation in laboratory measurements of the earth rotation and of Newton's gravitational constant are discussed. Several papers discuss the characteristics of gyroscopes and interferometers as sensors for inertial forces, starting from gyroscopes based on light waves and comparing their sensitivity to those based on matter waves. The final topic is the variation of fundamental constants, a subject that during the last years has attracted a lot of --
Download or read book New Developments in Atom Interferometry written by and published by . This book was released on 2002 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have pioneered new measurement techniques using coherent atom optics (such as beam-splitters, mirrors and lenses) to manipulate matter waves. During this grant period we built an improved atom interferometer which splits deBroglie waves of matter into two physically separate paths and then recombines the waves to make interference hinges of matter. Using this apparatus our experiments are extremely sensitive to any forces on the atoms.
