A Blue-Detuned MOT of CaF Molecules

In this talk, we report a blue-detuned magneto-optical trap (MOT) of CaF molecules operating well below the Doppler limit. Compared to a compressed red-detuned DC MOT, the blue MOT is much colder and denser, and achieves much higher phase-space density. Moreover, we directly measure the velocity and damping curves in the blue MOT, showing that a limited trap depth at high magnetic gradients is the primary cause of loss. We also find that the blue MOT improves the loading of molecules into optical tweezers, significantly reducing requirements on starting molecular number and experimental complexity. This could be relevant to creating large arrays of laser-coolable molecules, which are a promising platform for quantum science and precision measurement.