Ren Guoqi, Sun Huijie, Nakagawa Keiichi, Sugita Naohiko, Ito Yusuke
Opt Lett. 2024 May 1;49(9):2321-2324. doi: 10.1364/OL.522052.
In this Letter, we propose a crackless high-aspect-ratio processing method based on a temporally shaped ultrafast laser. The laser pulse is temporally split into two sub pulses: one with smaller energy is used to excite electrons but without ablation so that the applied pressure to the sample is weak, and the other one is used to heat the electrons and achieve material removal after it is temporally stretched by a chirped volume Bragg grating (CVBG). Compared with the conventional ultrafast laser processing, the crack generation is almost suppressed by using this proposed method. The hole depth increases more than 3.3 times, and the aspect ratio is improved at least 2.2 times. Moreover, processing dynamics and parameter dependence are further experimentally studied. It shows that the processing highly depends on the density of electrons excited by the first pulse (P1) and the energy of the second pulse (P2). This novel, to the best of our knowledge, method provides a new route for the precise processing of wide-bandgap materials.
在本信函中，我们提出了一种基于时域整形超快激光的无裂纹高深径比加工方法。激光脉冲在时间上被分割为两个子脉冲：能量较小的一个用于激发电子但不产生烧蚀，从而对样品施加的压力较弱，另一个用于加热电子，并在通过啁啾体布拉格光栅（CVBG）进行时间拉伸后实现材料去除。与传统超快激光加工相比，使用该方法几乎可以抑制裂纹的产生。孔深增加了3.3倍以上，深径比至少提高了2.2倍。此外，还进一步对加工动力学和参数依赖性进行了实验研究。结果表明，加工过程高度依赖于第一个脉冲（P1）激发的电子密度和第二个脉冲（P2）的能量。据我们所知，这种新颖的方法为宽带隙材料的精密加工提供了一条新途径。
