Fig. 1. Energy levels diagram of (a) Rb85 and (b) Cs133 in dark MOT. T: trapping laser, D: depumping laser, R: repumping laser.

Fig. 2. Brief diagram of optical elements in near-vacuum chamber. The angle between the double-mixed beams of the repumping lasers and depumping lasers is 168°.

Fig. 3. (a) Spatial position of Rb and Cs atom clouds with different power ratios of two repumping beams in double-mixed beams. The power ratios P1∶P2 of the Rb repumping beams are set to be 0, 0.47, and 4.44 from left to right, and the overlap ratios are measured to be 0, 0.65, and 1 based on the definition of Eq. (1). (b) The corresponding loading curves of the Rb atoms immerged in Cs atoms. The obtained collision-induced loss rates are 0.14(1), 0.17(3), and 0.23(3)s−1 according to the theoretical fit of Eq. (3).

Fig. 4. Ion signal spectra of RbCs of (a) single-mixed beam and (b) double-mixed beams.

Fig. 5. RbCs+ molecular ion intensities of single-mixed beam and double-mixed beams as functions of PA laser intensity. The solid lines are the fitted results of the experiment data by Eq. (4).