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Massively entangled bright states of light generated via entanglement with matter in harmonic generation

Ihar Babushkin, Sili Yi, Olga V. Smirnova, Misha Ivanov

Published Jan 1, 2025• 0 citations
Publisher

Abstract

We show that nonclassical, massively entangled bright states of light can be obtained during harmonic generation in strong optical fields due to entanglement with matter. The states are highly controllable by the pump pulse shape.
DOI
10.1364/cleo_fs.2025.ff122_1

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High-order harmonic generation (HHG) is a significant nonlinear phenomenon triggered by the interaction of intense laser fields with matter. As a high-quality coherent light source, it has found extensive applications in areas such as attosecond pulse generation and ultrafast spectroscopy. Recent studies have revealed the prevalent existence of nonclassical effects in high-harmonic radiation, including nonclassical photon statistics, intermodal correlations, and entanglement. It holds broad development prospects in directions including the generation of nonclassical states with high photon numbers, precise control of entanglement in solid-state systems, and integration with cavity quantum electrodynamics. This review systematically summarizes the research progress concerning the nonclassical effects in HHG. It begins with an overview of the semiclassical model and strong-field quantum theory, clarifying the differences in the quantum properties of harmonic fields when driven by coherent states versus nonclassical states. Subsequently, it focuses on various physical schemes for generating nonclassical optical field states, such as optical cat states and squeezed states, via this process. Research on strong-field HHG not only deepens our understanding of the fundamental nature of intense laser physics but also opens new avenues for the generation and application of quantum light sources in the extreme ultraviolet to X-ray spectral regions.
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