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.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 BJul 3, 20260 citations

Evaporative cooling from an optical dipole trap in microgravity

Christian Vogt, Marian Woltmann, Sven Herrmann +5 more

Evaporative cooling under microgravity is investigated in the free-fall experiment of ${}^{87}$ Rb atoms optically trapped from a temporarily dark magneto-optical trap in the drop tower in Bremen. The efficiency of evaporation is determined to be equal, with and without the effect of gravity.Evaporative cooling under microgravity is investigated in the free-fall experiment of ${}^{87}$Rb atoms optically trapped from a temporarily dark magneto-optical trap in the drop tower in Bremen. The efficiency of evaporation is determined to be equal, with and without the effect of gravity.

arXiv:1909.03800Physical Review AJan 28, 202030 citations

Dipole and multipole traps

Sergei V. Ryzhkov, A. Yu. Chirkov

Nov 13, 20180 citations

Quantum mixtures in microgravity

Ernst Maria Rasel

Optical and Quantum Sensing and Precision Metrology IIMar 5, 20260 citations

Dipole traps with mode-locked lasers

Roger B. M. Clarke, Thomas G. Graf, Erling Riis

Applied Physics BMay 1, 200010 citations

Evaporative cooling under microgravity is investigated in the free-fall experiment of

{}^{87}

Rb atoms optically trapped from a temporarily dark magneto-optical trap in the drop tower in Bremen. The efficiency of evaporation is determined to be equal, with and without the effect of gravity.