Laser cooling with adiabatic passage for type-Ⅱ transitions

We extend the idea of laser cooling with adiabatic passage to multi-level type-Ⅱ transitions.We find the cooling force can be significantly enhanced when a proper magnetic field is applied.That is because the magnetic field decomposes the multi-level system into several two-level sub-systems,hence the stimulated absorption and stimulated emission can occur in order,allowing for the multiple photon momentum transfer.We show that this scheme also works on the laser-coolable molecules with a better cooling effect compared to the conventional Doppler cooling.A reduced dependence on spontaneous emission based on our scheme is observed as well.Our results suggest this scheme is very feasible for laser cooling of polar molecules.