Effect of projection velocity and temperature on the reflection of ultracold atoms from a periodic one-dimensional corrugated magnetic potential

The spatial profile of ultracold atoms reflecting from an exponentially decaying magnetic potential depends on parameters such as the corrugation in the magnetic potential and the temperature of the atomic cloud. We report on experimental investigations of the effect of projection velocity which determines the strength of the interaction of the atom cloud with the magnetic potential and the effect of temperature of ultracold ${}^{87}\mathrm{Rb}$ atoms reflecting from a periodic one-dimensional corrugated magnetic potential. The magnetic potential is generated on an atom chip by a periodic permanent magnetic structure of period 10 $\mu$m. The amplitude of the corrugation is controlled by applying a uniform external-bias magnetic field.

Figure 1

Schematic of a perpendicularly magnetized grooved microstructure of period $a$. An external magnetic field is applied along the $y$ direction to induce corrugation.

Figure 2

Hybrid atom chip consisting of a periodic magnetic structure positioned on current-carrying wires.

Figure 3

Series of absorption images taken for different times of flight showing the profile of the atom cloud after interaction with the periodic magnetic potential for the parameters given in the text. $y$ and $z$ axes are along horizontal and downward directions, respectively.

Figure 4

Numerical simulation showing the spatial profile of the atoms for $v_z=-102$ mm/s and different times of flight shown next to each plot.

Figure 5

Projection $\Delta y$ of the profile on the $y$ axis versus time of flight for the parameters given in the text.

Figure 6

Series of absorption images where the magnitude of the projection velocity increases successively. In the first image,$v_z=0$ and the BEC has not interacted with the potential. $y$ and $z$ axes are along horizontal and downward directions, respectively.

Figure 7

Calculations showing atomic profile from (a) to (b) for $v_z=-32$, $-42$, $-62$, $-82$, and $-102$ mm/s, respectively, for 11 ms time of flight.

Figure 8

Series of absorption images showing the profile of the reflected atoms for different cloud temperature measured just before projecting the cloud toward the magnetic potential. $y$ and $z$ axes are along horizontal and downward directions, respectively.