State-labeling Wannier-Stark atomic interferometers

Abstract

Using cold 87 Rb atoms trapped in a 1D-optical lattice, atomic interferometers involving coherent superpositions between different Wannier-Stark atomic states are realized. Two different kinds of trapped interferometer schemes are presented: a Ramsey-type interferometer sensitive both to clock frequency and external forces, and a symmetric accordion-type interferometer, sensitive to external forces only. We evaluate the limits in terms of sensitivity and accuracy of those schemes and discuss their application as force sensors. As a first step, we apply these interferometers to the measurement of the Bloch frequency and the demonstration of a compact gravimeter.

Atomic multiwave interferometer in an optical lattice

“…4. The second harmonic frequency component given by the FFT data is found to be 1136.74 (5) Hz, corresponding to ν B = 568.37(3) Hz, which is consistent with the result of the least-square fitting method and [41]. The uncertainties of ν B given here are the statistical error.…”

“…A least-square fitting of the fringe with Lorentzian function gives a value of T B = 1.759(1) ms [ Fig. 3(a)], corresponding to a Bloch frequency of ν B = 568.5(3) Hz, which is consistent with [41]. We can also get the Bloch frequency by calculating the fast Fourier transform (FFT) of the fringes with long time data accumulation.…”

“…3(b)], leading to a decrease of signal-to-noise ratio. Moreover, an increase of T necessitates a longer trapping time T t , leading to a loss of atoms [41] and to the increase of the fluctuations of P e as the experiment is detection noise limited. The short-term sensitivity (at 1 s) for different T is shown in the inset of Fig.…”

“…This multiwave interferometry phenomenon is similar to that described in [18], where Bloch oscillations are interpreted as periodic rephasing of the many WS components of a pure quasimomentum. In our multiwave interferometer, Raman transitions are used as a state labeling tool changing both the internal and external state of the atoms, allowing for an efficient detection based on the internal state populations [39][40][41], and not on the external state (position or momentum) [23,27,28,31]. This method gives interference fringes without any modulation of the lattice depth.…”

Compact atomic gravimeter based on a pulsed and accelerated optical lattice

“…They consist in levitating the atoms by means of the laser light [14][15][16][17][18][19][20]. Currently three kinds of experiments based on atoms trapped in a vertical optical lattice are in progress [17][18][19][20]: using atoms confined in an amplitude-modulated vertical optical lattice [17], using atom interferometry involving a coherent superposition between different Wannier-Stark atomic states in a one-dimensional (1-D) optical lattice [20], and combining a Ramsey-Bordé interferometer with Bloch oscillations in a quasistationary vertical standing wave [18,19]. In the last experiment atoms interact with the optical lattice in the middle of the interferometer sequence during about 100 ms.…”