Realization of High Optical Density Rb Magneto-optical Trap

Cabrera Gutierrez, Naty Citlali

Wenzel Salzmann, J. Eng, Ulrich Poschinger +2 more

Yanxu Han, Liu Y, Chunhong Zhang +2 more

We report experimental demonstration of a magneto-optical trap (MOT) of Rb atoms with a high optical density. With 2.2-cm-diameter cooling laser beams, we achieve an optical density of nearly 11 for about 2.6 × 10 10 trapped Rb atoms with the beam intensity of about 6.6 mW/cm per beam. The temperature of the cold atoms is about 250 μK. Furthermore, by ramping the magnetic field gradient from 8 G/cm to about 20 G/cm, the atomic cloud in the MOT is compressed and the optical density is up to 16.

Yang Liu, Jinghui Wu, Bao‐Sen Shi +1 more

We build up a novel setup of a two-dimensional (2D) 85 Rb magneto-optical trap (MOT) with a high optical depth (OD) of 38. Such a MOT trap of 85 Rb has several advantages as compared to the normal three-dimensional ellipsoidal MOT. Firstly, it will greatly enhance atom-photon interaction due to the large OD. Then, the dephasing caused by the magnetic gradient will be decreased in the long axis of the 2D MOT, which we want to avoid from in the experiments. The metastable ground level dephasing rate was γ 21 = 0.008γ 31 , which is much less than that in a normal MOT. The total number of atoms in this MOT was measured to be 9.1 × 10 8 .

William McGehee, Daniel S. Barker, Wenqi Zhu +5 more

T. Aoki, Yuki Yamanaka, Y. Sakemi +1 more

We demonstrate the simultaneous magneto-optical trapping (MOT) of Rb and Sr and examine the characteristic loss of Rb in the MOT due to photoionization by the cooling laser for Sr. The photoionization cross section of Rb in the $5P_{3/2}$ state at 461 nm is determined to be $1.2\times10^{-17}$ cm$^2$. It is important to consider this loss rate to realize a sufficiently large number of trapped Rb atoms to achieve a quantum degenerate mixture of Rb and Sr.