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Imperfect Recollisions in High-Harmonic Generation in Solids
1Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001, USA.
Physical Review Letters
|May 2, 2020
Summary
High-harmonic generation in hexagonal boron nitride exhibits a double-peak structure due to imperfect electron-hole pair recollisions. An extended recollision model (ERM) explains this phenomenon and its dependence on crystal properties and laser polarization.
Area of Science:
- Condensed matter physics
- Quantum optics
- Materials science
Background:
- High-harmonic generation (HHG) is a key process for producing coherent extreme ultraviolet and X-ray radiation.
- Understanding electron dynamics in solids under intense laser fields is crucial for HHG control.
- Hexagonal boron nitride (hBN) is a promising material for exploring light-matter interactions due to its unique electronic properties.
Purpose of the Study:
- To theoretically investigate the mechanisms behind high-harmonic generation in hexagonal boron nitride.
- To explain the origin of the double-peak structure observed in subcycle emission profiles.
- To develop a model that accounts for imperfect recollisions and related quantum effects.
Main Methods:
- Theoretical investigation using an extended recollision model (ERM).
- Incorporation of electron-hole pair polarization energy, Berry curvature, and transition-dipole phases into the model.
- Analysis of spectrotemporal characteristics of emitted harmonics.
Main Results:
- Imperfect electron-hole pair recollisions lead to an electron-hole-pair polarization energy.
- This energy causes a distinct double-peak structure in subcycle emission profiles.
- The ERM successfully explains the differences in harmonic emission parallel and perpendicular to laser polarization.
Conclusions:
- Imperfect recollisions are a general phenomenon in HHG, linked to delocalized wave packets and Berry curvature.
- The developed ERM provides a comprehensive framework for understanding HHG in materials like hBN.
- This work offers insights into controlling HHG through material properties and laser polarization.
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