Clean hundred-µJ-level sub-6-fs blue pulses generated with helium-assisted solid thin plates

Area of Science:

• Physics
• Optics
• Ultrafast Science

Background:

• Generating high-energy, few-cycle pulses in the blue spectrum is challenging due to material damage.
• Existing methods often suffer from low energy output or complex setups.

Purpose of the Study:

• To develop a robust method for generating high-energy, few-cycle blue pulses.
• To investigate and mitigate optical damage during pulse generation.

Main Methods:

• Utilized a two-stage, helium-assisted pulse compression apparatus with solid thin plates.
• Employed commercially available chirped mirrors within a gas-filled chamber.
• Optimized spectral broadening in a helium environment to prevent solid thin plate damage.

Main Results:

• Generated 85 µJ, 5.5 fs blue pulses (350-500 nm) with 96% energy concentration.
• Achieved the highest energy sub-6 fs blue pulses reported to date.
• Demonstrated elimination of solid thin plate damage in a helium environment.
• Maintained excellent output power stability (0.39% rms fluctuations over 1 hour).

Conclusions:

• Helium-assisted pulse compression effectively prevents optical damage, enabling high-energy blue pulse generation.
• The developed technique offers a stable and efficient route to few-cycle blue pulses.
• Hundred-microjoule level few-cycle blue pulses will advance ultrafast and strong-field research.