Off-axis excitation of hydrogenlike atoms by twisted photons

TL;DR

This paper demonstrates that twisted photons with high angular momentum can excite hydrogen-like atoms in unique ways when the beam's axis is offset from the atom, revealing new selection rules and observable effects.

Contribution

It introduces a novel excitation mechanism using off-axis twisted photons, expanding understanding of atomic excitation by structured light beyond traditional constraints.

Findings

Twisted photons can excite atomic states not accessible by plane waves.

Off-axis excitation leads to new selection rules for atomic transitions.

Implications for quantum control and measurement with structured light.

Abstract

We show that the twisted photon states, or photon states with large ($> \hbar$) angular momentum projection ($m_\gamma$) in the direction of motion, can photoexcite atomic levels for a hydrogen-like atom that are novel and distinct and are not restricted by $m_\gamma$, when the symmetry axis of the twisted-photon beam does not coincide with the center of the atomic target. Selection rules are given and interesting implications and observables for the above process are pointed out.