A compact and solely fiber coupled dual-species double-MOT system loads a 3D-MOT at a rate of ~109 atoms/s (~108 atoms/s) for rubidium (potassium). A Mach-Zehnder pulse sequence (π/2 - π - π/2) creates a quantummeachanical superposition of two internal states that, due to the transferred photon momentum, enclose an area in space-time. The interferometer output ports are read out by pulsed state-selective fluorescence detection.
As a common source for dual species interferometry, an optical dipole trap at a wavelength of 2µm is available. By making use of this far off-resonance dipole trap (FORT) many systematics, such as
- Wavefront errors due to transverse atomic spread,
- Initial colocation of the two species,
- Coriolis force,
- Detection noise,
- etc. ...
can be mitigated. Also, the benign light shifts of our trapping wavelength allow for robust and efficient laser cooling within the trap.
Additionally, we have realized the first BEC in an optical trap at a wavelength of 2µm.