Blue-detuned molecular magneto-optical trap schemes based on Bayesian optimization

Direct laser cooling and trapping of molecules to temperature below the Doppler limit and density exceeding 108 are challenging due to the sub-Doppler heating effects of a molecular magneto-optical trap (MOT). In our previous paper [S. Xu, Phys. Rev. Res. 4, L042036 (2022)2643-156410.1103/PhysRevResearch.4.L042036], we presented a general approach to engineering the sub-Doppler force by tuning the AC Stark shift with the addition of a blue-detuned laser. Here, by employing the Bayesian optimization method to optical Bloch equations, we have identified multiple blue-detuned MOT schemes for the CaF molecule. From the three-dimensional Monte Carlo simulation, we obtained a MOT temperature and density of 14 μK and 4.5×108 cm-3, respectively. Our findings present a potential avenue for directly loading molecular MOTs into conservative traps, which can capitalize on the high density and low temperature of the MOTs.