Intensity control of few-cycle laser pulses

Abstract

Controlling the intensity of few-cycle laser pulses-often with fine and continuous tunability-is essential for applications ranging from strong-field physics and attosecond science to ultrafast spectroscopy, nonlinear optics, and precision material processing. Yet this remains challenging due to their octave-spanning bandwidth and high sensitivity to dispersion. Conventional polarization-based methods typically rely on ultrabroadband optics, which are complex and costly. We demonstrate a robust and broadly applicable approach that enables precise intensity control while avoiding these demanding optical requirements. Applied to an ∼800 nm laser, the method allows pulse energy tuning over a factor of ∼25 while maintaining a sub-6 fs pulse duration after post-compression in an argon-filled hollow fiber and chirped mirror system. Validation through high-harmonic generation in krypton reveals clear intensity-dependent harmonic yields across 30-190TW/cm². This work provides a practical and effective route to stable, tunable few-cycle pulses for both experimental and applied settings.