Work

Emergence of nonclassical radiation in strongly laser-driven quantum systems

Year: 2026

Type: article

Abstract: We present an analytical framework for the emergence of nonclassical radiation in strongly laser-driven quantum systems, with a focus on high-order harmonic generation (HHG). Starting from a Pauli–Fierz description, we employ a parametric factorization of the coupled light–matter wavefunction that reduces the dynamics to coupled equations for a field-driven electronic state and a quantized light mode. Within this framework, we identify a simple and predictive mechanism for nonclassicality: it originates from the nonlinear dependence of the electronic dipole response on the light-mode coordinate. An approximately constant dipole yields coherent radiation, a linear dependence produces squeezing, and higher-order nonlinearities give rise to Wigner-function negativity. We illustrate this mechanism for atomic and molecular model systems and analyze its scaling in multi-emitter configurations, indicating routes toward high-photon-number nonclassical radiation in HHG. Our results provide a transparent connection between strong-field dynamics and quantum-optical properties of emitted light, offering a basis for engineering nonclassical states in intense laser–matter interactions.

Source: New Journal of Physics

DOI: 10.1088/1367-2630/aeae67

Authors: Ivan Gonoskov, Christian Hünecke, Stefanie Gräfe

Institutions: Friedrich Schiller University Jena, Fraunhofer Institute for Applied Optics and Precision Engineering

Language: English

Topic: Laser-Matter Interactions and Applications

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,610

Funder: Deutsche Forschungsgemeinschaft