Cao Binh Xuan, Hoang Phuong Le, Ahn Sanghoon, Kim Jeng-O, Kang Heeshin, Noh Jiwhan
Department of Laser and Electron Beam Application, Korea Institute of Machinery & Materials (KIMM), Daejeon 34103, Korea.
Department of Nano-Mechatronics, Korea University of Science and Technology (UST), Daejeon 34113, Korea.
Sensors (Basel). 2017 Jul 1;17(7):1540. doi: 10.3390/s17071540.
In modern high-intensity ultrafast laser processing, detecting the focal position of the working laser beam, at which the intensity is the highest and the beam diameter is the lowest, and immediately locating the target sample at that point are challenging tasks. A system that allows in-situ real-time focus determination and fabrication using a high-power laser has been in high demand among both engineers and scientists. Conventional techniques require the complicated mathematical theory of wave optics, employing interference as well as diffraction phenomena to detect the focal position; however, these methods are ineffective and expensive for industrial application. Moreover, these techniques could not perform detection and fabrication simultaneously. In this paper, we propose an optical design capable of detecting the focal point and fabricating complex patterns on a planar sample surface simultaneously. In-situ real-time focus detection is performed using a bandpass filter, which only allows for the detection of laser transmission. The technique enables rapid, non-destructive, and precise detection of the focal point. Furthermore, it is sufficiently simple for application in both science and industry for mass production, and it is expected to contribute to the next generation of laser equipment, which can be used to fabricate micro-patterns with high complexity.
在现代高强度超快激光加工中，检测工作激光束的焦点位置（此时强度最高且光束直径最小）并立即将目标样品定位在该点是具有挑战性的任务。一种能够使用高功率激光进行原位实时焦点确定和加工的系统，一直是工程师和科学家们的迫切需求。传统技术需要复杂的波动光学数学理论，利用干涉和衍射现象来检测焦点位置；然而，这些方法对于工业应用来说效率低下且成本高昂。此外，这些技术无法同时进行检测和加工。在本文中，我们提出了一种光学设计，它能够同时检测焦点并在平面样品表面制造复杂图案。使用带通滤波器进行原位实时焦点检测，该滤波器仅允许检测激光传输。该技术能够快速、无损且精确地检测焦点。此外，它足够简单，可应用于科学和工业领域的大规模生产，并且有望为下一代激光设备做出贡献，该设备可用于制造具有高复杂性的微图案。
