Physics

Anderson localization

Angular momentum

Femtosecond

Rotational energy

Raman scattering

Amplitude

Excited state

Atomic physics

Scattering

Supersonic speed

Raman spectroscopy

Laser

Mechanics

Quantum mechanics

Classical mechanics

Quantum

Physical Review Letters

We observe and study the phenomenon of Anderson localization in a system of true quantum kicked rotors. Nitrogen molecules in a supersonic molecular jet are cooled down to 27~K and are rotationally excited by a periodic train of 24~high-intensity femtosecond pulses. Exponential distribution of the molecular angular momentum - the most unambiguous signature of Anderson localization - is measured directly by means of coherent Raman scattering. We demonstrate the suppressed growth of the molecular rotational energy with the number of laser kicks and study the dependence of the localization length on the kick strength. Both timing and amplitude noise in the pulse train is shown to destroy the localization and revive the diffusive growth of angular momentum.

Experimental Observation of Dynamical Localization in Laser-Kicked Molecular Rotors