Nonresonant rotational Raman excitation of linear molecules by periodic sequences of ultra-short laser pulses allows for the realization of a paradigm system - the quantum kicked rotor. This apparently simple physical system has drawn much interest within the last decades, especially due to its role in the field of quantum chaos. In the case of periodic kicking, the wave function of a quantum rotor dynamically localizes in the angular momentum space, similarly to Anderson localization of the electronic wave function in disordered solids. I will present the first direct observation of dynamical localization in a system of true rotors. The suppressed growth of rotational energy is demonstrated, as well as the noise-induced recovery of diffusion, indicative of classical dynamics. In a second study I demonstrate the coherent control of quantum chaos and a loss of control in the classical limit of laser-molecule interaction.
This work advances the general understanding of the dynamics of laser kicked molecules and complements previous studies of the quantum kicked rotor in a system of cold atoms. The possibility of control in classically chaotic systems has far reaching implications for the ultimate prospect of using coherence to control chemical reactions.