Proposal for accelerated evaporative cooling in optical traps under microgravity
Lin Yilin, Bowen Xu, Shuyu Zhou
In microgravity environments, the evaporative cooling time required to prepare a Bose–Einstein condensate (BEC) in a crossed optical dipole trap is significantly longer than that observed in ground-based experiments using identical apparatus. This slowdown arises from the simultaneous decrease in both trap depth and trap frequency of the trap under microgravity conditions, which results in an extended duration necessary for achieving thermal equilibrium. To address this issue, we propose incorporating a saddle-shaped blue-detuning light field to create a composite optical trap. This approach effectively mitigates the decline of trap frequency while simultaneously reducing the depth of the composite trap, thereby facilitating rapid evaporative cooling. Numerical simulations indicate that this strategy allows the atomic phase-space density to approach the Bose–Einstein condensation threshold in less than 4 s under microgravity. Such performance represents an order-of-magnitude improvement in the evaporative cooling rate of optical dipole traps operating in microgravity. This advancement not only facilitates rapid BEC preparation under orbital conditions but also opens new avenues for analogous experiments in ground-based drop towers.
Journal of the Optical Society of America B•Jul 3, 2026•0 citations