High-order harmonic source spanning up to the oxygen K-edge based on filamentation pulse compression

Area of Science:

• Laser Physics
• Attosecond Science
• Nonlinear Optics

Background:

• High-order harmonic generation (HHG) is a key process for producing extreme ultraviolet (XUV) and soft X-ray radiation.
• Generating ultrashort and phase-stable laser pulses is crucial for driving HHG to probe ultrafast dynamics.
• Existing sources often face limitations in pulse duration, stability, or spectral range.

Purpose of the Study:

• To develop a novel laser source capable of generating sub-two-cycle pulses at 1.8 µm.
• To utilize this source for driving high-order harmonic generation (HHG) extending beyond the oxygen K-edge.
• To provide a high-repetition-rate, high-temporal-resolution tool for advanced scientific studies.

Main Methods:

• Two-stage pulse compression utilizing filamentation in a nonlinear medium.
• Generation of a 0.2 TW, carrier-envelope-phase stable laser pulse with a duration of 11.8 fs.
• Driving HHG in a helium gas target.

Main Results:

• Achieved a 0.2 TW peak power with sub-two-cycle pulse duration (11.8 fs) at 1.8 µm.
• Successfully generated high-order harmonics extending beyond the oxygen K absorption edge (~543 eV).
• Demonstrated a 1 kHz repetition rate, enabling efficient data acquisition.

Conclusions:

• The developed laser source is a powerful tool for attosecond science and HHG research.
• Its unique properties make it suitable for investigating ultrafast phenomena in solids and molecules.
• The extended spectral range opens new possibilities for studying electronic and structural dynamics.