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Updated: Aug 23, 2025
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Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
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Role of Spin-Orbit Coupling in High-Order Harmonic Generation Revealed by Supercycle Rydberg Trajectories
N Mayer1, S Beaulieu2, Á Jiménez-Galán1,3
1Max-Born-Institute, Max-Born Straße 2A, 12489 Berlin, Germany.
Physical Review Letters
|November 4, 2022
Summary
Long-lived Rydberg states significantly contribute to high-harmonic generation, challenging previous assumptions. This study provides experimental evidence of these stable trajectories influencing harmonic emission.
Area of Science:
- Atomic, Molecular, and Optical Physics
- Quantum Optics
- Attosecond Science
Background:
- High-harmonic generation (HHG) is typically a sub-laser-cycle process.
- The role of long-lived Rydberg states in HHG was recently theorized but experimentally unconfirmed.
Purpose of the Study:
- To provide direct experimental evidence for the contribution of long-lived Rydberg states to HHG.
- To investigate the dynamics of these Rydberg states within the laser pulse.
- To demonstrate their impact on macroscopic harmonic emission.
Main Methods:
- Utilizing a combination of counterrotating circularly polarized fundamental and second harmonic fields.
- Tracking Rydberg state dynamics using spin-orbit evolution in the ionic core (spin-orbit Larmor clock).
- Performing microscopic simulations to confirm the effect on harmonic emission.
Main Results:
- Direct experimental observation of very long and stable Rydberg trajectories contributing to HHG.
- Confirmation of Rydberg state influence on harmonic emission via simulations.
- Demonstration that this radiation can form a well-collimated macroscopic far-field signal.
Conclusions:
- Long-lived Rydberg trajectories play a significant, non-negligible role in HHG.
- These findings challenge the conventional understanding of HHG mechanisms.
- The study highlights a new pathway for controlling and enhancing HHG signals.
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