Selective ablation-assisted two-photon stereolithography for effective nano- and microfabrication

The two-photon stereolithography (TPS) process has strong merits for the direct fabrication of 2-D and 3-D microstructures with sub-100-nm resolution. In this paper, we report an effective fabrication process in which selective ablation-assisted TPS (SA-TPS) was used to ameliorate some of the limitations of the TPS process. In SA-TPS, two processes (namely, an additive process of two-photon induced photocuring and a subtractive process of selective laser ablation) were performed sequentially using a single femtosecond laser optical scanning system. The effectiveness of the proposed process was demonstrated in several applications, including precise high-resolution patterning at resolution levels higher than those achievable using the TPS process, and the fabrication of structures with high mechanical sensitivity.