We present a compact and transportable inertial sensor for precision sensing of rotations and accelerations. The sensor consists of a dual Mach-Zehnder-type atom interferometer operated with laser-cooled 87 Rb. Raman processes are employed to coherently manipulate the matter waves. We describe and characterize the experimental apparatus. A method for passing from a compact geometry to an extended interferometer with three independent atom-light interaction zones is proposed and investigated. The extended geometry will enhance the sensitivity by more than two orders of magnitude which is necessary to achieve sensitivities better than 10 −8 rad/s/ √ Hz.
We present and investigate different external cavity diode laser (ECDL) configurations for the manipulation of neutral atoms, wavelength-stabilized by a narrow-band high transmission interference filter. A novel diode laser, providing high output power of more than 1 W, with a linewidth of less than 85 kHz, based on a self-seeded tapered amplifier chip has been developed. Additionally, we compare the optical and spectral properties of two laser systems based on common laser diodes, differing in their coating, as well as one, based on a distributed-feedback (DFB) diode. The linear cavity setup in all these systems combines a robust and compact design with a high wavelength tunability and an improved stability of the optical feedback compared to diode laser setups using diffraction gratings for wavelength discrimination.
In response to ESA's Call for proposals of 5 March 2007 of the COSMIC VISION 2015VISION -2025 plan of the ESA science programme, we propose a M-class satellite mission to test of the Equivalence Principle in the quantum domain by investigating the extended free fall of matter waves instead of macroscopic bodies as in the case of GAUGE, MICROSCOPE or STEP. The satellite, called Matter Wave Explorer of Gravity, will carry an experiment to test gravity, namely the measurement of the equal rate of free fall with various isotopes of distinct atomic species with precision cold atom interferometry in the vicinity of the earth. This will allow for a first quantum test the Equivalence Principle with spin polarised particles and with pure fermionic and bosonic atomic ensembles. Due to the space conditions, the free fall of Rubidium and Potassium isotopes will be compared with a maximum accelerational sensitivity of 5·10−16 m/s 2 corresponding to an accuracy of the test of the Equivalence Principle of 1 part in 1016 . Besides the primary scientific goal, the quantum test of the Equivalence Principle, the mission can be extended to provide additional information about the gravitational field of the earth or for testing theories of fundamental processes of decoherence which are investigated by various theory groups in the context of quantum gravity phenomenology. In
We report on a simple novel trapping scheme for the generation of Bose-Einstein condensates of 87 Rb atoms. This scheme employs a near-infrared single beam optical dipole trap combined with a weak magnetic quadrupole field as used for magneto-optical trapping to enhance the confinement in axial direction. Efficient forced evaporative cooling to the phase transition is achieved in this weak hybrid trap via reduction of the laser intensity of the optical dipole trap at constant magnetic field gradient.A simple and robust method for the generation of quantum degenerate atomic gases with decent particle number and repetition rate is of interest for the study of their fundamental properties [1][2][3] or their applications in atomic inertial sensors [4] and gravimeters [5], as well as in microgravity [6]. Here, we describe a very simple method for the generation of a Bose-Einstein condensate (BEC) in a single beam near-infrared optical dipole trap (ODT). Optical dipole traps offer great potential with respect to the criteria mentioned above. Forced evaporative cooling in such traps is usually achieved by reducing the power of the ODT laser beam [7] and rethermalization times are generally short due to the high trapping frequencies in the kHz-regime usually provided by an ODT. However, power reduction also reduces the confinement of the atoms in the trap which in turn negatively affects trap frequencies, peak atomic density, elastic collision rate, and as a consequence the efficiency of forced evaporation. This counteracts the gain in phase space density by the cooling of the atomic cloud, thus preventing the regime of run-away evaporation in an ODT with this simple method [8]. Quantum degeneracy can nonetheless be reached in these traps, provided the initial atomic and phase space densities were high enough [9,10]. Nevertheless, the necessary compromise between high initial densities and high initial trapping volume severely affects the maximum number of particles in the BEC and additional sophisticated concepts for reaching optimized initial atomic and phase space densities may be required [11].The most simple realization of an ODT is to focus one single far-off resonant high power laser beam onto the atomic ensemble. However, due to the rather low confinement of the atoms in the axial direction of these single beam ODTs, the high initial atomic and phase space densities needed to reach quantum degeneracy are very hard to realize. This is particularly the case for single beam ODTs formed from a near-infrared laser source [12]. In * Rasel@iqo.uni-hannover.de contrast, the wavelength of a CO 2 laser of ∼ 10.6 µm provides an axial trapping frequency an order of magnitude higher compared to an ODT formed from e.g. a Nd:YAG laser at a wavelength of 1064 nm. This stronger confinement is still enough to allow for the realization of a BEC with more than 10 5 atoms [13]. Nevertheless, this method is bound to the use of far-infrared laser wavelengths with all the associated technical implications. If the use of laser wavelength...
A collaboration between European research groups is developing novel atomic inertial quantum sensors based on matter-wave optics and Raman interferometry. For this purpose we are implementing a gravimeter and a gyroscope using ultra cold atoms as test masses. Inertial quantum sensors could represent a new tool for the precise detection of faint forces and tiny rotations. According to the principle of these sensors, the measured physical quantity will be converted into a frequency, which can be measured with highest accuracy. The items of atom interferometry will range from fundamental physical tests to many practical applications such as: local gravity measurements, allowing a precise underground mapping, and space navigation. In this contest the main goal is to realize modular and portable systems.
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