Laser-Matter Interaction: Classical Regime versus Quantum Regime

TL;DR

This paper compares classical and quantum regimes of laser-matter interaction, highlighting how nuclear excitation can occur with fewer photons than atomic interactions, simplifying experimental setups.

Contribution

It introduces a mean-field to rate equation transition for nuclear interactions and demonstrates reduced photon requirements for nuclear excitation.

Findings

Nuclear excitation occurs at lower photon numbers than atomic interactions.

Classical field strength is insufficient for nuclear excitation, requiring a quantum approach.

Reduced experimental complexity for nuclear laser-matter interaction experiments.

Abstract

Doppler backscattering of optical laser photons on a "flying mirror" of relativistic electrons promises to yield coherent photons with MeV-range energies. We compare the nuclear interaction of such a laser pulse with the standard atom-laser interaction. The mean-field description of atoms must be replaced by a rate equation and the classical field strength, far too faint in nuclei, by the dipole transition rate. Significant nuclear excitation occurs for photon numbers much smaller than typical for atoms. That drastically reduces the requirements on the experimental realization of a "flying mirror".