Low-velocity matter wave source for atom interferometry produced by Zeeman-tuned laser cooling and magneto-optic trapping

Michael Christ, Jörg Helge Müller, D. Bettermann +7 more

David H. McIntyre, Shannon K. Mayer, N.J. Silva

We have developed a rubidium atomic funnel for use as a matter-wave source in experiments in atom interferometry and atom optics. The funnel utilizes the techniques of laser cooling and trapping to produce a low-velocity beam of cold rubidium atoms. Atoms from a thermal beam are first slowed in a tapered magnetic field using 1D Zeeman slowing. The atoms are then loaded into a 2D magneto-optic trap or atomic funnel. The trap cools and compresses the atoms, which are then ejected from the trap by moving molasses formed with frequency-shifted laser beams. These slow atoms will be diffracted by microfabricated transmission gratings as part of a three-grating atom interferometer.

Yang Wei, Sun Dali, Zhou Lin +2 more

To prepare cold lithium atoms for atomic interferometry experiments, we have carried out experimental researches on Zeeman deceleration and magneto-optical trap (MOT) of lithium atoms. We have also designed and implemented a compact adjustable Zeeman slower with an inner water cooling chamber, to decelerate the velocity of the 7Li atom beam from 600 m/s down to 60 m/s, and load them into the MOT. The loading rate is 5108 /s, the total trapped atom number is 1109 , and the lowest temperature of the atom cloud is 220 30 K. Then we investigate the dependence of lifetime of 7Li atoms in optical molasses on the detuning of trapping laser beams. The above results lay a foundation for further sub-Doppler cooling, optical trap based on evaporative cooling, and atomic interferometry experiments.

Jörg Helge Müller, D. Bettermann, V. Rieger +10 more

Keng Yeow Chung

R. Freytag

This thesis presents progress toward the production of ultracold CsYb molecules. To this end, an apparatus capable of producing magneto optical traps of Yb and Cs was designed, built and tested. Both atoms are produced in a dual species oven and both slowed to low speeds by a single Zeeman slower. From the Zeeman slower atoms are captured in a dual-species magneto-optical trap. To cool caesium the 852 nm D2 transition is addressed by two lasers for cooling and repump. For ytterbium the 399 nm 1S0 ⇒ 1P1 transition is addressed for the Zeeman slower and the 556 nm 1S0 ⇒ 3P1 transition is addressed for the magneto-optical trap. The 399 nm light is produced by two homebuilt diode lasers in an injection-seeding setup, which can produce up to 100 mW. The 556 nm light is produced from a commercial frequency doubled fiber laser, which can produce up to 260 mW. The Zeeman slower is characterised experimentally for both Cs and Yb, and the results compared to those of a numerical simulation of the slower for Yb. The velocity distribution exiting the slower is very sensitive to the exact magnetic field profile, the laser power and detuning of the laser light. The number of atoms loaded into the magneto-optical trap was investigated as a function of the magnetic field gradient, the laser power and the laser detuning. The capture velocity of the Yb MOT is small because the linewidth of the MOT transition is narrow, and so we investigated the influence of broadening the laser linewidth by adding multiple finely-spaced sidebands to the laser light. After optimisation the caesium MOT trapped 5.5 ×10^8 atoms at 125 ± 4 μK. The ytterbium MOT trapped 4.7 ×10^9 atoms at 81 ± 2 μK. Lastly we demonstrate that both MOTs can be produced in the same vacuum chamber simultaneously.