Attosecond nonlinear optics using gigawatt-scale isolated attosecond pulses

TLDR

High‑energy isolated attosecond pulses needed for nonlinear attosecond experiments and pump–probe spectroscopy are currently lacking. The study proposes and demonstrates a robust method to generate intense isolated attosecond pulses for nonlinear attosecond optics experiments. The method uses two‑colour field synthesis with an energy‑scaling high‑order harmonic generation to achieve 1.3 µJ pulse energy. The 500‑as pulse, measured by nonlinear autocorrelation, is the shortest and highest‑energy pulse capable of inducing nonlinear phenomena, and its 2.6 GW peak power surpasses that of an EUV free‑electron laser.

Abstract

High-energy isolated attosecond pulses required for the most intriguing nonlinear attosecond experiments as well as for attosecond-pump/attosecond-probe spectroscopy are still lacking at present. Here we propose and demonstrate a robust generation method of intense isolated attosecond pulses, which enable us to perform a nonlinear attosecond optics experiment. By combining a two-colour field synthesis and an energy-scaling method of high-order harmonic generation, the maximum pulse energy of the isolated attosecond pulse reaches as high as 1.3 μJ. The generated pulse with a duration of 500 as, as characterized by a nonlinear autocorrelation measurement, is the shortest and highest-energy pulse ever with the ability to induce nonlinear phenomena. The peak power of our tabletop light source reaches 2.6 GW, which even surpasses that of an extreme-ultraviolet free-electron laser.