High-Efficiency Plasma-Based Compressor for Ultrafast Soft X-Ray Free-Electron Lasers.

Area of Science:

• Physics
• Plasma Physics
• Laser Science

Background:

• Generating intense, femtosecond X-ray pulses is vital for studying matter under extreme conditions.
• Conventional optical compressors in free-electron lasers (FELs) are inefficient in the soft X-ray range.

Purpose of the Study:

• To propose and validate a novel, high-efficiency plasma-based compressor for soft X-ray chirped-pulse amplification (CPA).
• To overcome the efficiency limitations of current X-ray FEL technology.

Main Methods:

• Utilizing highly ionized noble gas plasma for compression.
• Exploiting strong refractive index dispersion near ionic resonances.
• Performing simulations to demonstrate pulse compression and power enhancement.

Main Results:

• Achieved over 70% transmission efficiency around 5.2 nm.
• Demonstrated compression of a 25 fs FEL pulse to 1.4 fs.
• Showcased peak power boost to over 100 GW with high-energy throughput.

Conclusions:

• The plasma-based compressor offers a transformative solution for soft X-ray CPA.
• This approach provides a scalable pathway to compact, high-brightness attosecond FEL sources.
• The technique is extendable across the soft X-ray to vacuum ultraviolet range using different ions.