Artificial intelligent focusing of a microbeam system based on reinforcement learning Yanlin Li, Hongjin Mou, Wei Zhang, Jinlong Guo, Shi An, Guanghua Du and Xiaojun Liu Eur. Phys. J. Plus, 140 4 (2025) 327 Published online: 22 April 2025 DOI: 10.1140/epjp/s13360-025-06221-3