We realize beam splitters and mirrors for atom waves by employing a sequence of light pulses rather than individual ones. In this way we can tailor atom interferometers with improved sensitivity and ...accuracy. We demonstrate our method of composite pulses by creating a symmetric matter-wave interferometer which combines the advantages of conventional Bragg- and Raman-type concepts. This feature leads to an interferometer with a high immunity to technical noise allowing us to devise a large-area Sagnac gyroscope yielding a phase shift of 6.5 rad due to the Earth's rotation. With this device we achieve a rotation rate precision of 120 nrad s(-1) Hz(-1/2) and determine the Earth's rotation rate with a relative uncertainty of 1.2%.
We employ light-induced double Bragg diffraction of delta-kick collimated Bose-Einstein condensates to create three symmetric Mach-Zehnder interferometers. They rely on (i) first-order, (ii) two ...successive first-order, and (iii) second-order processes which demonstrate the scalability of the corresponding momentum transfer. With respect to devices based on conventional Bragg scattering, these symmetric interferometers double the scale factor and feature a better suppression of noise and systematic uncertainties intrinsic to the diffraction process. Moreover, we utilize these interferometers as tiltmeters for monitoring their inclination with respect to gravity.
We report on the realization of a compact atomic Mach-Zehnder-type Sagnac interferometer of 13.7 cm length, which covers an area of 19 mm2 previously reported only for large thermal beam ...interferometers. According to Sagnac's formula, which holds for both light and atoms, the sensitivity for rotation rates increases linearly with the area enclosed by the interferometer. The use of cold atoms instead of thermal atoms enables miniaturization of Sagnac interferometers without sacrificing large areas. In comparison with thermal beams, slow atoms offer better matching of the initial beam velocity and the velocity with which the matter waves separate. In our case, the area is spanned by a cold atomic beam of 2.79 m s−1, which is split, deflected and combined by driving a Raman transition between the two hyperfine ground states of 87Rb in three spatially separated light zones. The use of cold atoms requires a precise angular alignment and high wave front quality of the three independent light zones over the cloud envelope. We present a procedure for mutually aligning the beam splitters at the microradian level by making use of the atom interferometer itself in different configurations. With this method, we currently achieve a sensitivity of .
Raman laser pulses are used to induce coherent tunneling between neighboring sites of a vertical 1D optical lattice. Such tunneling occurs when the detuning of a probe laser from the atomic ...transition frequency matches multiples of the Bloch frequency, allowing for a spectroscopic control of the coupling between Wannier-Stark (WS) states. In particular, we prepare coherent superpositions of WS states of adjacent sites, and investigate the coherence time of these superpositions by realizing a spatial interferometer. This scheme provides a powerful tool for coherent manipulation of external degrees of freedom of cold atoms, which is a key issue for quantum information processing.
We report on the phase-locking of two diode lasers based on self-seeded tapered amplifiers. In these lasers, a reduction of linewidth is achieved using narrow-band high-transmission interference ...filters for frequency selection. The lasers combine a compact design with a Lorentzian linewidth below 200 kHz at an output power of 300 mW for a wavelength of 780 nm. We characterize the phase noise of the phase-locked laser system and study its potential for coherent beam-splitting in atom interferometers.
Raman-laser spectroscopy of Wannier-Stark states Tackmann, G.; Pelle, B.; Hilico, A. ...
Physical review. A, Atomic, molecular, and optical physics,
12/2011, Letnik:
84, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Raman lasers are used as a spectroscopic probe of the state of atoms confined in a shallow one-dimensional (1D) vertical lattice. For sufficiently long laser pulses, resolved transitions in the ...bottom band of the lattice between Wannier Stark states corresponding to neighboring wells are observed. Couplings between such states are measured as a function of the lattice laser intensity and compared to theoretical predictions, from which the lattice depth can be extracted. Limits to the linewidth of these transitions are investigated. Transitions to higher bands can also be induced, as well as between transverse states for tilted Raman beams. All these features allow for a precise characterization of the trapping potential and for an efficient control of the atomic external degrees of freedom.
Double Bragg diffraction: A tool for atom optics Giese, E.; Roura, A.; Tackmann, G. ...
Physical review. A, Atomic, molecular, and optical physics,
11/2013, Letnik:
88, Številka:
5
Journal Article
We present a high resolution atom interferometer gyroscope based on stimulated Raman transitions of neutral atoms. Employing three separate interaction zones allows to enlarge the signal while ...maintaining high compactness.
The use of retro-reflection in light-pulse atom interferometry under microgravity conditions naturally leads to a double-diffraction scheme. The two pairs of counterpropagating beams induce ...simultaneously transitions with opposite momentum transfer that, when acting on atoms initially at rest, give rise to symmetric interferometer configurations where the total momentum transfer is automatically doubled and where a number of noise sources and systematic effects cancel out. Here we extend earlier implementations for Raman transitions to the case of Bragg diffraction. In contrast with the single-diffraction case, the existence of additional off-resonant transitions between resonantly connected states precludes the use of the adiabatic elimination technique. Nevertheless, we have been able to obtain analytic results even beyond the deep Bragg regime by employing the so-called "method of averaging," which can be applied to more general situations of this kind. Our results have been validated by comparison to numerical solutions of the basic equations describing the double-diffraction process.
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