双光子聚合多次快速扫描机制与小线宽研究

采用自由基浓度起伏理论并考虑光镊集聚效应,理论研究了飞秒激光双光子聚合多次快速扫描的线宽问题。根据双光子光聚合过程中自由基浓度随时间变化的关系,考虑光镊力及自由扩散效应对自由基分布的影响,得到了多次快速扫描加工线宽的表达式。研究了多次扫描过程中产生自由基浓度随扫描次数的变化、双光子聚合加工不同扫描次数下加工线宽随激光功率的变化、多次扫描过程中间隔时间对于加工线宽的影响。多次扫描的线宽表达式可以直接回归至单次扫描的一般公式,且理论结果与文献中实验加工线宽相吻合,两者误差在2%。控制扫描间隔时间,减少自由基的向外扩散运动以及被树脂材料内大分子猝灭,使得活性自由基的分布更为集中,可以获得更小的加工线宽。研究结果为飞秒激光双光子更小线宽加工的研究提供了新的思路,为飞秒激光多次快速扫描加工提供了理论依据。

Linewidth of femtosecond laser two-photon polymerization multiple-rapid-scanning

Using the theory of free radical concentration fluctuation combined with the effect of optical tweezers, this paper studies the linewidth of femtosecond laser two-photon polymerization multiple-fast-scanning processing theoretically. According to the relationship between the change of free radical concentration and time in the two-photon photopolymerization processing, considering the influence of the optical tweezers on the free radical distribution range, it obtains the formula of the linewidth of multiple-rapid-scanning processing. It also presents the relationship between linewidth and scanning speed, laser power, and interval time. The results can be regressed to the general formula of single-scanning and are in good agreement with the experimental results in the literature. The study provides a new idea for studying the femtosecond laser two-photon processing to obtain a smaller processing linewidth, and provides a theoretical basis for the femtosecond laser multiple-rapid-scanning processing.