Li Hang, Li Yahui, Shang Yang, Yue Mengmeng, Luo Duan, Xue Yanhua, Gao Guilong, Tian Jinshou
State Key Laboratory of Ultrafast Optical Science and Technology, Xi'an Institute of Optics and Precision Mechanics, Xi'an 710119, China.
Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China.
Nanomaterials (Basel). 2025 Sep 12;15(18):1410. doi: 10.3390/nano15181410.
Ultrafast laser processing can produce micro/nanostructures, which is of great interest in advanced manufacturing. Ultrafast laser-induced events include non-equilibrium dynamic phenomena, occurring on the femtosecond to picosecond time scale and nanometer to micron space scale. Single-shot ultrafast imaging can provide multiple time-correlated evolution frames in one non-repeatable event with a temporal resolution of sub-picoseconds. However, previous approaches suffer from degraded spatial resolution, which is a bottleneck in microscopic imaging. For the spatial-frequency multiplexing methods based on structured illumination, a reconstruction strategy was proposed utilizing the frames' conjugate symmetry in the Fourier domain. The spatial resolution is double that of the traditional algorithm by evaluating with synthetic data, revealing that the reconstruction resolution can reach the diffraction limitation. A two-frame microscopic system was constructed with a frame interval of 300 fs and a maximum spatial resolution of 1.4 μm. The interaction between a femtosecond laser and a fused silica glass plate was captured in a single shot and the dynamic evolution of the induced plasma was observed, verifying the application feasibility in ultrafast laser processing, providing experimental observations for interaction mechanism research and theoretical model optimization.
超快激光加工能够产生微纳结构，这在先进制造领域具有重大意义。超快激光诱导的事件包括非平衡动态现象，其发生在飞秒到皮秒的时间尺度以及纳米到微米的空间尺度上。单次超快成像能够在一个不可重复的事件中提供多个时间相关的演化帧，时间分辨率可达亚皮秒级。然而，先前的方法存在空间分辨率下降的问题，这是微观成像中的一个瓶颈。对于基于结构照明的空间频率复用方法，提出了一种利用傅里叶域中帧的共轭对称性的重建策略。通过合成数据评估，其空间分辨率是传统算法的两倍，这表明重建分辨率能够达到衍射极限。构建了一个双帧微观系统，帧间隔为300飞秒，最大空间分辨率为1.4微米。在单次拍摄中捕捉到了飞秒激光与熔融石英玻璃板之间的相互作用，并观察到了诱导等离子体的动态演化，验证了其在超快激光加工中的应用可行性，为相互作用机理研究和理论模型优化提供了实验观测结果。
