Transferring orbital and spin angular momenta of light to atoms

TL;DR

This paper investigates how intense Laguerre-Gaussian light beams transfer orbital and spin angular momentum to hydrogen atoms, revealing complex dependencies on light polarization, phase, and atom position through advanced simulations and quantum analysis.

Contribution

It provides a detailed ab initio analysis of angular momentum transfer from structured light to atoms, including the effects of polarization, phase, and spatial positioning.

Findings

Angular momentum transfer depends on light polarization and vortex position.

Laguerre-Gaussian beams can induce angular momentum exchange exceeding hbar per photon.

Quantum-trajectory analysis offers physical insight into the absorption process.

Abstract

Light beams carrying orbital angular momentum, such as Laguerre-Gaussian beams, give rise to the violation of the standard dipolar selection rules during the interaction with matter yielding, in general, an exchange of angular momentum larger than hbar per absorbed photon. By means of ab initio 3D numerical simulations, we investigate in detail the interaction of a hydrogen atom with intense Gaussian and Laguerre-Gaussian light pulses. We analyze the dependence of the angular momentum exchange with the polarization, the orbital angular momentum, and the carrier-envelope phase of light, as well as with the relative position between the atom and the light vortex. In addition, a quantum-trajectory approach based on the de Broglie-Bohm formulation of quantum mechanics is used to gain physical insight into the absorption of angular momentum by the hydrogen atom.