Compact millijoule Yb³⁺:CaF₂ laser with 162 fs pulses

Area of Science:

• Laser Physics
• Plasma Physics
• Materials Science

Background:

• Ultrafast relativistic laser-plasma interactions require high-energy, short-pulse lasers.
• Compact and robust laser systems are crucial for advanced experimental setups.
• Chirped Pulse Amplification (CPA) is a key technique for achieving high pulse energies.

Purpose of the Study:

• To develop a compact, diode-pumped, chirped pulse regenerative amplifier system.
• To optimize the system for probing ultrafast relativistic laser-plasma processes.
• To demonstrate a robust CPA laser solution in the millijoule energy range.

Main Methods:

• Utilizing a chirped volume Bragg grating (CVBG) as a combined pulse stretcher and compressor.
• Employing Yb3+:CaF2 as the gain medium for broad bandwidth support.
• Implementing spectral gain shaping and chirped mirrors for dispersion compensation.

Main Results:

• Achieved a pulse duration of 162 fs.
• Obtained an output pulse energy of 1 mJ before compression and 910 µJ after compression.
• Demonstrated a large spectral bandwidth of 16 nm (FWHM) with Yb3+:CaF2.

Conclusions:

• The developed compact CPA laser system is suitable for probing ultrafast relativistic laser-plasma processes.
• The CVBG offers a robust solution for stretcher/compressor functions in millijoule-class CPA systems.
• Yb3+:CaF2 is an effective gain medium for broadband amplification in this laser architecture.