A Rb–Cs dual-species magneto-optical trap

We describe a three-dimensional (3D) magneto-optical trap (MOT) capable of simultaneously capturing ⁸⁵Rb and ¹³³Cs atoms. Unlike conventional setups, our system utilizes two separate laser systems that are combined before entering the vacuum chamber, enabling the simultaneous trapping of two different atomic species. We trapped ⁸⁵Rb and ¹³³Cs atoms using relatively low total power: 8 mW cooling and 4 mW repump for ⁸⁵Rb, and 7.5 mW cooling and 1.5 mW repump for ¹³³Cs. The number of trapped atoms was 1.6 × 10⁸ for ⁸⁵Rb and 1.4 × 10⁸ for ¹³³Cs. The optical depths were 3.71 for ⁸⁵Rb and 3.45 for ¹³³Cs. The temperature of trapped atoms was ∼200 μK for ⁸⁵Rb and ∼200 μK for ¹³³Cs. Our 3D MOT setup allows full horizontal optical access to the trapped atomic ensembles without spatial interference from the trapping or repump laser beams. Our vacuum system is also quite simple, avoiding much of the complexity typically encountered in similar dual-species systems. However, the red detuning of the cooling laser used for atomic trapping in our system is relatively small, leaving room for further optimization. This system offers a versatile platform for exploring complex phenomena in ultracold atom physics, such as Rydberg molecule formation and interspecies interactions.