Ensemble of Linear Molecules in Nondispersing Rotational Quantum States: A Molecular Stopwatch

Abstract

We present a method to create nondispersing rotational quantum states in an ensemble of linear molecules with a well-defined rotational speed in the laboratory frame. Using a sequence of transformlimited laser pulses, we show that these states can be established through a process of rapid adiabatic passage. Coupling between the rotational and pendular motion of the molecules in the laser field can be used to control the detailed angular shape of the rotating ensemble. We describe applications of these rotational states in molecular dissociation and ultrafast metrology.