Three-dimensional isotropic microfabrication in glass using spatiotemporal focusing of high-repetition-rate femtosecond laser pulses
Yuanxin Tan, Haotian Lv, Jian Xu, Aodong Zhang, Yunpeng Song, Jianping Yu, Wei Chen, Yuexin Wan, Zhaoxiang Liu, Zhaohui Liu, Jia Qi, Yangjian Cai, Ya Cheng
Abstract
To improve the processing efficiency and extend the tuning range of 3D isotropic fabrication, we apply the simultaneous spatiotemporal focusing (SSTF) technique to a high-repetition-rate femtosecond (fs) fiber laser system. In the SSTF scheme, we propose a pulse compensation scheme for the fiber laser with a narrow spectral bandwidth by building an extra-cavity pulse stretcher. We further demonstrate truly 3D isotropic microfabrication in photosensitive glass with a tunable resolution ranging from 8 µm to 22 µm using the SSTF of fs laser pulses. Moreover, we systematically investigate the influences of pulse energy, writing speed, processing depth, and spherical aberration on the fabrication resolution. As a proof-of-concept demonstration, the SSTF scheme was further employed for the fs laser-assisted etching of complicated glass microfluidic structures with 3D uniform sizes. The developed technique can be extended to many applications such as advanced photonics, 3D biomimetic printing, micro-electromechanical systems, and lab-on-a-chips.