Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review Letters

Mechanism of Angular Momentum Exchange between Molecules and Laguerre-Gaussian Beams

Adrian Alexandrescu, Dan Cojoc, Enzo Mario Di Fabrizio

Published Jun 20, 2006• 100 citations
Publisher

Abstract

We derive the interaction Hamiltonian between a diatomic molecule and a Laguerre-Gaussian beam under the assumption of a small spread of the center of mass wave function of the molecule in comparison with the beam waist. Considering the dynamical variables of the center of mass, vibrational, rotational, and electronic motion, we show that, within the electronic dipole approximation, the orbital angular momentum of the field couples with the rotational and electronic motion. The changes in the transition probabilities and selection rules induced by the field orbital angular momentum and the applicability of the derived interaction mechanisms for polyatomic molecules are discussed.

DOI
10.1103/physrevlett.96.243001

Related papers

Electronic and centre of mass transitions driven by Laguerre–Gaussian beams

A Alexandrescu, Enzo Mario Di Fabrizio, Dan Cojoc

We derive the interaction Hamiltonian of a Laguerre–Gaussian beam with a simple atomic system, under the assumption of a small spread of the centre of mass wavefunction in comparison with the waist of the Laguerre–Gaussian beam and taking into account the centre of mass motion of the atomic system. Using the properties of regular spherical harmonics the internal and centre of mass dynamical variables are separated without making any multipolar expansion. The features of angular momentum exchange process assisted by Laguerre–Gaussian beams and the influence of their winding number on the selection rules and transition probability of internal and centre of mass motion are discussed.

arXiv:quant-ph/0412110•Journal of Optics B Quantum and Semiclassical Optics•Feb 19, 2005•22 citations

Angular momentum transfer in interaction of Laguerre-Gaussian beams with atoms and molecules

Pradip Kumar Mondal, Bimalendu Deb, Sonjoy Majumder

The exchange of orbital angular momentum between a Laguerre-Gaussian beam of light and the center-of-mass motion of an atom or molecule is well known. We show that the orbital angular momentum of light can also be transferred to the internal electronic or rotational motion of an atom or a molecule provided the internal and center-of-mass motions are coupled. However, this transfer does not happen directly to the internal motion, but via center-of-mass motion. If atoms or molecules are cooled down to the recoil limit, then an exchange of angular momentum between the quantized center-of-mass motion and the internal motion is possible during the interaction of cold atoms or molecules with the Laguerre-Gaussian beam. The orientation of the exchanged angular momentum is determined by the sign of the winding number of the Laguerre-Gaussian beam. We present selective results of numerical calculations for the quadrupole transition rates in the interaction of the Laguerre-Gaussian beam with an atomic Bose-Einstein condensate to illustrate the underlying mechanism of light orbital angular momentum transfer. We discuss how the alignment of diatomic molecules will facilitate exploration of the effects of light orbital angular momentum on the electronic motion of molecules.

arXiv:1403.2881•Physical Review A•Jun 26, 2014•92 citations

Interaction of a Laguerre–Gaussian beam with trapped Rydberg atoms

Koushik Mukherjee, Sonjoy Majumder, Pradip Kumar Mondal +1 more

Abstract Previous studies show that within paraxial limit and electric dipole approximations, the orbital angular momentum (OAM) of a Laguerre–Gaussian (LG) beam rotates the whole atom about the beam axis but does not affect the internal electronic motion. The contribution of the Gaussian part of the LG beam profile to the angular momentum exchange is not usually taken into account. In this paper, we develop a theory which shows that not only the OAM of a LG beam, but also the geometry of the beam cross section, plays an important role in the electronic lowest-order transitions in the interaction of the beam with a trapped Rydberg atom, due to the large span of its electronic wavefunctions. In this interaction, the standard dipole selection rules do not hold and our results show that the otherwise forbidden transitions can become sufficiently probable.

arXiv:1702.05969•Journal of Physics B Atomic Molecular and Optical Physics•Oct 4, 2017•14 citations

Orbital Angular Momentum Exchange in the Interaction of Twisted Light with Molecules

M. Babiker, C. R. Bennett, Davıd L. Andrews +1 more

In the interaction of molecules with light endowed with orbital angular momentum, an exchange of orbital angular momentum in an electric dipole transition occurs only between the light and the center of mass motion; i.e., internal "electronic-type" motion does not participate in any exchange of orbital angular momentum in a dipole transition. A quadrupole transition is the lowest electric multipolar process in which an exchange of orbital angular momentum can occur between the light, the internal motion, and the center of mass motion. This rules out experiments seeking to observe exchange of orbital angular momentum between light beams and the internal motion in electric dipole transitions.

Physical Review Letters•Sep 11, 2002•278 citations

Atom dynamics in multiple Laguerre-Gaussian beams

L. Allen, M. Babiker, W. K. Lai +1 more

The leading radiation forces acting on an atom or ion subject to linearly polarized Laguerre-Gaussian (LG) light are studied. Particular emphasis is laid on the orbital angular momentum effects associated with LG light. The optical Bloch equations appropriate for the adiabatic approximation are derived and used to evaluate the forces and associated torque governing the atomic motion. The steady-state dynamics of the atom are explored for atoms subject to a single beam and multiple independent counterpropagating beams. The main features responsible for the dynamics of the atom, together with the dipole potentials characteristic of Laguerre-Gaussian light, are identified and discussed. The theory is illustrated by the numerical integration of the equation of motion for ${\mathrm{Mg}}^{+}$ ions in various beam configurations. This yields information on trajectories, velocity evolution, and vibrational frequencies at potential minima. Interesting effects involving a reciprocal interplay between motions in orthogonal directions are demonstrated. Such features are purely dependent on the orbital angular momentum property of the light. Their possible use in controlling atomic motion is investigated. \textcopyright{} 1996 The American Physical Society.

Physical Review A•Nov 1, 1996•89 citations

Center of mass transitions in the quadrupole interaction of atomic systems with Laguerre-Gaussian beams

Adrian Alexandrescu, Enzo Mario Di Fabrizio, Dan Cojoc

In the frame of paraxial approximation, we consider the case of free atoms interacting with an Lagtierre-Gaussian beam. Using Power-Zienaii-Wooley scheme, we calculate the interaction Hamiltonian in the quadrupole approximation and including center of mass motion of the atomic system. The expression of the center of mass transition probability is derived in analytic form. The influence of the beam and atomic system parameters on the center of mass transition probability are discussed.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Aug 15, 2005•0 citations
We derive the interaction Hamiltonian between a diatomic molecule and a Laguerre-Gaussian beam under the assumption of a small spread of the center of mass wave function of the molecule in comparison with the beam waist. Considering the dynamical variables of the center of mass, vibrational, rotational, and electronic motion, we show that, within the electronic dipole approximation, the orbital angular momentum of the field couples with the rotational and electronic motion. The changes in the transition probabilities and selection rules induced by the field orbital angular momentum and the applicability of the derived interaction mechanisms for polyatomic molecules are discussed.
We derive the interaction Hamiltonian of a Laguerre–Gaussian beam with a simple atomic system, under the assumption of a small spread of the centre of mass wavefunction in comparison with the waist of the Laguerre–Gaussian beam and taking into account the centre of mass motion of the atomic system. Using the properties of regular spherical harmonics the internal and centre of mass dynamical variables are separated without making any multipolar expansion. The features of angular momentum exchange process assisted by Laguerre–Gaussian beams and the influence of their winding number on the selection rules and transition probability of internal and centre of mass motion are discussed.
The exchange of orbital angular momentum between a Laguerre-Gaussian beam of light and the center-of-mass motion of an atom or molecule is well known. We show that the orbital angular momentum of light can also be transferred to the internal electronic or rotational motion of an atom or a molecule provided the internal and center-of-mass motions are coupled. However, this transfer does not happen directly to the internal motion, but via center-of-mass motion. If atoms or molecules are cooled down to the recoil limit, then an exchange of angular momentum between the quantized center-of-mass motion and the internal motion is possible during the interaction of cold atoms or molecules with the Laguerre-Gaussian beam. The orientation of the exchanged angular momentum is determined by the sign of the winding number of the Laguerre-Gaussian beam. We present selective results of numerical calculations for the quadrupole transition rates in the interaction of the Laguerre-Gaussian beam with an atomic Bose-Einstein condensate to illustrate the underlying mechanism of light orbital angular momentum transfer. We discuss how the alignment of diatomic molecules will facilitate exploration of the effects of light orbital angular momentum on the electronic motion of molecules.
Abstract Previous studies show that within paraxial limit and electric dipole approximations, the orbital angular momentum (OAM) of a Laguerre–Gaussian (LG) beam rotates the whole atom about the beam axis but does not affect the internal electronic motion. The contribution of the Gaussian part of the LG beam profile to the angular momentum exchange is not usually taken into account. In this paper, we develop a theory which shows that not only the OAM of a LG beam, but also the geometry of the beam cross section, plays an important role in the electronic lowest-order transitions in the interaction of the beam with a trapped Rydberg atom, due to the large span of its electronic wavefunctions. In this interaction, the standard dipole selection rules do not hold and our results show that the otherwise forbidden transitions can become sufficiently probable.
In the interaction of molecules with light endowed with orbital angular momentum, an exchange of orbital angular momentum in an electric dipole transition occurs only between the light and the center of mass motion; i.e., internal "electronic-type" motion does not participate in any exchange of orbital angular momentum in a dipole transition. A quadrupole transition is the lowest electric multipolar process in which an exchange of orbital angular momentum can occur between the light, the internal motion, and the center of mass motion. This rules out experiments seeking to observe exchange of orbital angular momentum between light beams and the internal motion in electric dipole transitions.
The leading radiation forces acting on an atom or ion subject to linearly polarized Laguerre-Gaussian (LG) light are studied. Particular emphasis is laid on the orbital angular momentum effects associated with LG light. The optical Bloch equations appropriate for the adiabatic approximation are derived and used to evaluate the forces and associated torque governing the atomic motion. The steady-state dynamics of the atom are explored for atoms subject to a single beam and multiple independent counterpropagating beams. The main features responsible for the dynamics of the atom, together with the dipole potentials characteristic of Laguerre-Gaussian light, are identified and discussed. The theory is illustrated by the numerical integration of the equation of motion for Mg+{\mathrm{Mg}}^{+}Mg+ ions in various beam configurations. This yields information on trajectories, velocity evolution, and vibrational frequencies at potential minima. Interesting effects involving a reciprocal interplay between motions in orthogonal directions are demonstrated. Such features are purely dependent on the orbital angular momentum property of the light. Their possible use in controlling atomic motion is investigated. \textcopyright{} 1996 The American Physical Society.