Atom Michelson Interferometer on a Chip Using a Bose-Einstein Condensate

An atom Michelson interferometer is implemented on an “atom chip.” The chip uses lithographically patterned conductors and external magnetic fields to produce and guide a Bose-Einstein condensate. Splitting, reflecting, and recombining of condensate atoms are achieved by a standing-wave light field having a wave vector aligned along the atom waveguide. A differential phase shift between the two arms of the interferometer is introduced by either a magnetic-field gradient or with an initial condensate velocity. Interference contrast is still observable at 20% with an atom propagation time of 10 ms.

Figure 1

(a) Schematic drawing of the atom chip (not to scale). The dimensions of the chip are $5\mathrm{c}\mathrm{m}\times 2\mathrm{c}\mathrm{m}$. (b) A photo image of the atom chip glued onto a copper holder.

Figure 2

(a) The splitting pulse is turned on at $t=0$. (b) The two split clouds propagate in the opposite direction at $0<t<T/2$. (c) The reflection pulse is turned on at $t=T/2$. (d) The clouds propagate back toward to the center of the waveguide at $T/2<t<T$. (e) The recombining pulse is turned on at $t=T$ when the clouds are overlapped.

Figure 3

Interference pattern of (a) $\mathrm{\text{phase shift}}=2n\pi$ and (b) $\mathrm{\text{phase shift}}=(2n+1)\pi$. The absorption images are taken 10 ms after the recombining pulse.

Figure 4

Interference fringes after 1 ms propagation time in the waveguide. The magnetic gradient is turned on for $500\mu \mathrm{s}$ and the average separation of clouds during the magnetic pulse is $8.82\mu \mathrm{m}$.

Figure 5

Interference fringes after about 10 ms propagation in the waveguide.