Quantum resonance, Anderson localisation and selective manipulations in molecular mixtures by ultrashort laser pulses

TL;DR

This paper shows how ultrashort laser pulses can induce quantum resonance and Anderson localization in molecular rotations, enabling selective excitation in mixtures like nitrogen isotopologues at room temperature.

Contribution

It introduces a novel laser pulse technique to control molecular rotation and alignment, demonstrating selectivity in molecular mixtures based on quantum phenomena.

Findings

Observation of quantum resonance effects in molecular rotational dynamics

Demonstration of Anderson-like localization in angular momentum

Effective selective rotational excitation in nitrogen isotopologue mixtures

Abstract

We demonstrate that the current laser technology used for field-free molecular alignment via a cascade of Raman rotational transitions allows for observing long-discussed non-linear quantum phenomena in the dynamics of the periodically kicked rotor. This includes the scaling of the absorbed energy near the conditions of quantum resonance and Anderson-like localisation in the angular momentum. Based on these findings, we suggest a novel approach to tunable selective rotational excitation and alignment in a molecular mixture, using trains of short laser pulses. We demonstrate the efficiency of this approach by applying it to a mixture of two nitrogen isotopologues (14N2 and 15N2), and show that strong selectivity is possible even at room temperature.