Yilun Zhou, Bin Liu, Hengfeng Yan, Jinbo Wu, Zhihong Hu, Xiaoyan Qiu, Junyang Dong, Sha Wang, Chong Liu
We demonstrate a cost-effective and compact chirped pulse amplification (CPA) picosecond laser system with high average power and pulse energy. Based on four Yb:YAG rods, the amplifier produces 5.1 mJ pulses at 102 W average power. The initial output beam quality M 2 factor was measured to be 1.33, which was further improved to 1.09 by spherical aberration compensation. The amplified pulses were compressed to a duration of 1 ps with an efficiency exceeding 93%. An improved dual-rod cascaded compensation method for thermally induced birefringence was implemented in the high-energy Yb:YAG amplifier, reducing the depolarization loss to 0.29% at 102 W output power while enhancing the extraction efficiency.