Highly efficient cryogenic Yb:YLF regenerative amplifier with 250  W average power

Area of Science:

• Laser Physics
• Materials Science

Background:

• Yb:YLF lasers are crucial for high-power applications.
• Optimizing gain and efficiency in Yb:YLF amplifiers is an ongoing challenge.

Purpose of the Study:

• To develop an efficient, high-power cryogenic regenerative amplifier.
• To investigate the performance of Yb:YLF at 1019 nm using the c-axis transition.

Main Methods:

• Utilized a diode-pumped cryogenic regenerative amplifier setup.
• Employed the c-axis 1019 nm transition of Yb:YLF for amplification.
• Seeded the system with a fiber front-end delivering 30 nJ pulses with 2 ns duration.

Main Results:

• Achieved a record average power of 370 W at a 50 kHz repetition rate.
• Demonstrated a high extraction efficiency of 78%.
• Obtained output pulses centered at 1019.15 nm with 1.25 nm bandwidth, supporting sub-1.5 ps durations.

Conclusions:

• The c-axis 1019 nm transition of Yb:YLF offers superior gain for high-power amplification.
• Thermal lensing in Yb:YLF limits TEM00 beam quality and system stability above 250 W.