Detecting of photons in optical fields of complicated spatial structure

TL;DR

This paper proposes a photon detection method sensitive to electromagnetic field gradients to analyze the quantum properties of complex spatial optical fields, especially those with angular momentum, using atomic excitation techniques.

Contribution

It introduces a novel detection approach for characterizing the quantum spatial structure of optical fields with complex angular momentum.

Findings

Laguerre-Gauss and Bessel beams are not truly hollow due to magnetic and electric field gradients.

Gradient-sensitive detectors can analyze the quantum properties of singular light beams.

The method enables quantum-level analysis of spatial and angular momentum properties.

Abstract

We show that a photon detector, sensitive to the gradients of electromagnetic fields, or to magnetic fields, should be a useful tool to characterize the quantum properties of spatially-dependent optical fields. We discuss the excitation of an atom on a magnetic dipole or electric quadrupole transitions with the spiral photons of a Laguerre-Gauss (LG) or Bessel beams. We show that these beams are not true hollow beams, due to the presence of magnetic fields and gradients of electric fields on beam axis. This approach paves the way to an analysis at the quantum level of the spatial structure and angular momentum properties of singular light beams.