Bose-Einstein condensate inside a Bragg-reflecting atom cavity

We experimentally realize an atom cavity consisting of a magnetic trap and an optical lattice that extends over the whole trap. When displaced sufficiently from the center of the magnetic trap, dynamics of the atoms are characterized by magnetic confinement on one side of the cavity and Bragg reflection due to the optical lattice on the other side. We demonstrate this atom cavity by recording the momentum-space oscillation of a Bose-Einstein condensate inside the cavity as a function of time. This atom-cavity configuration presents the possibility of realizing a Mach-Zehnder-type atom interferometer.

Figure 1

(a) Schematic drawing of a Bragg-reflecting atomic cavity (BRAC). (b) Momentum distribution of a BEC inside the atom cavity at the indicated times (linear grayscale representation).

Figure 2

(Color online) Schematic drawing of the experimental setup for the BRAC. The absorption imaging beam is perpendicular to the optical lattice so that the effect of the lattice can be observed. Bias magnetic fields are used to control the location and depth of the trap.

Figure 3

(Color online) Momentum distribution of the BEC inside the atom cavity (linear grayscale representation). The BEC is initially displaced by different amounts from the center of the Z trap. (a)-(d) correspond to 30, 44, 60, and $74\mu \text{m}$ displacements, respectively.

Figure 4

(Color online) Oscillation period $\mathit{T}$ as a function of $1/x_0$. A linear fit of the experimental data yields a slope of $137\text{ms}\mu \text{m}$.

Figure 5

(a) Momentum distribution of the BEC inside the atom cavity obtained from the simulation. (b) Corresponding spatial distribution of the BEC.

Figure 6

TOF image of BECs after 7 ms in a trap, with an initial displacement of $74\mu \text{m}$. Leaking BECs from multiple Bragg reflections are observed.