Towards intense single-digit attosecond pulses with a 100-mJ-class mid-infrared sub-cycle laser

TL;DR

This paper reports a groundbreaking 100-mJ-class mid-infrared sub-cycle laser that generates high-energy, ultra-broadband soft X-ray pulses, advancing the development of attosecond pulses for probing ultrafast phenomena.

Contribution

The authors developed a high-energy, carrier-envelope-phase-stable mid-infrared laser system capable of producing sub-cycle pulses with unprecedented energy and bandwidth, enabling new attosecond pulse generation.

Findings

Produced 50-mJ, 6.7-fs pulses at 2.26 μm wavelength.

Generated supercontinuum coherent soft X-ray with unprecedented bandwidth.

Validated results with three-dimensional time-dependent Schrödinger equation simulations.

Abstract

The duration of isolated attosecond pulses created via high-order harmonic generation is determined by the number of optical cycles in the driving laser. Achieving shorter attosecond soft X-ray pulses requires minimizing the number of cycles while maintaining a high pulse energy. Here, we demonstrate a carrier-envelope-phase-stable, 100-mJ-class sub-cycle mid-infrared laser that produces a supercontinuum coherent soft X-ray with unprecedented bandwidth. The system delivers 50-mJ, 6.7-fs (0.88-cycle) pulses at a center wavelength of 2.26 $\mu$m - over two orders of magnitude more energetic than any previous sub-cycle laser. We applied the system to high-order harmonic generation and compared the results to simulations based on the three-dimensional time-dependent Schr\"odinger equation to identify unique features of sub-cycle lasers. This work represents a decisive step toward high-energy half-cycle lasers and high-energy single-digit attosecond soft X-ray pulses that can be used to probe matter and light-matter interactions at previously inaccessible temporal resolutions.