Compact 80 W, 1 MHz Femtosecond Chirped Pulse Amplification Laser System Based on a Yb-Doped Fiber and a Yb:YAG Thin Rod

We present a hybrid chirped pulse amplification (CPA) laser system based on Yb-doped fiber and Yb:YAG thin rod. The laser system demonstrates a novel approach to generate high average power up to the 100-W level by using a Yb:YAG thin rod without pump guiding at room temperature. A Yb-doped all-fiber laser with an output power of 7 W and a repetition rate of 1 MHz is amplified to an output power of 126.2 W in simple and compact two-stage amplifiers consisting of a single fiber crystal (SCF) and a Yb:YAG thin rod. To the best of our knowledge, this is the highest output power of Yb:YAG thin-rod amplifier with good beam quality obtained without pump guiding at room temperature. After using a thin-film polarizer (TFP) to remove the thermal depolarization, a linearly polarized ultrashort pulse laser with an average power of 115.2 W is obtained. An output power of 80.6 W with a pulse width of 580 fs is achieved after pulse compression. The central pulse contains 84.1% of the total pulse energy, corresponding to a pulse peak power of 116.9 MW.