Microwave-Assisted Coherent Control Of Ultracold Polar Molecules In A Ladder-Type Configuration Of Rotational States

We demonstrate microwave-assisted coherent control of ultracold (RbCs)-Rb-85-Cs-133 molecules in a ladder-type configuration of rotational states. Specifically, we use a probe and a control MW field to address the transitions between the J = 1 -> 2 and J = 2 -> 3 rotational states of the X-1 sigma(+)(v = 0) vibrational level, respectively, and use the control field to modify the response of the probe MW transition by coherently reducing the population of the intermediate J = 2 state. We observe that an increased Rabi frequency of the control field leads to broadening of the probe spectrum splitting and a shift of the central frequency. We apply Akaike's information criterion (AIC) to conclude that the observed coherent spectral response appears across the crossover regime between electromagnetically induced transparency and Aulter-Townes splitting. Our work is a significant development in microwave-assisted quantum control of ultracold polar molecules with multilevel configuration.