Pimenov Sergei M, Zavedeev Evgeny V, Jaeggi Beat, Neuenschwander Beat
Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia.
Institute for Applied Laser, Photonics and Surface Technologies ALPS, Bern University of Applied Sciences, CH-3400 Burgdorf, Switzerland.
Materials (Basel). 2023 Jan 13;16(2):795. doi: 10.3390/ma16020795.
We study the properties of laser-induced periodic surface structures (LIPSS) formed on titanium-doped diamond-like nanocomposite (DLN) a-C:H:Si:O films during ablation processing with linearly-polarized beams of a visible femtosecond laser (wavelength 515 nm, pulse duration 320 fs, pulse repetition rates 100 kHz-2 MHz, scanning beam velocity 0.05-1 m/s). The studies are focused on (i) laser ablation characteristics of Ti-DLN films at different pulse frequencies and constant fluence close to the ablation threshold, (ii) effects of the polarization angle rotation on the properties of low spatial frequency LIPSS (LSFL), and (iii) nanofriction properties of the 'rotating' LIPSS using atomic force microscopy (AFM) in a lateral force mode. It is found that (i) all LSFL are oriented perpendicular to the beam polarization direction, so being rotated with the beam polarization, and (ii) LSFL periods are gradually changed from 360 ± 5 nm for ripples parallel to the beam scanning direction to 420 ± 10 nm for ripples formed perpendicular to the beam scanning. The obtained results are discussed in the frame of the surface plasmon polaritons model of the LIPSS formation. Also, the findings of the nanoscale friction behavior, dependent on the LIPSS orientation relative to the AFM tip scanning direction, are presented and discussed.
我们研究了在掺钛类金刚石纳米复合材料（DLN）a-C:H:Si:O薄膜上，使用可见光飞秒激光（波长515nm，脉冲持续时间320fs，脉冲重复率100kHz - 2MHz，扫描光束速度0.05 - 1m/s）的线偏振光束进行烧蚀处理时形成的激光诱导周期性表面结构（LIPSS）的特性。研究集中在：（i）不同脉冲频率下，在接近烧蚀阈值的恒定能量密度下，Ti-DLN薄膜的激光烧蚀特性；（ii）偏振角旋转对低空间频率LIPSS（LSFL）特性的影响；（iii）使用原子力显微镜（AFM）在横向力模式下研究“旋转”LIPSS的纳米摩擦特性。研究发现：（i）所有LSFL都垂直于光束偏振方向取向，因此会随着光束偏振而旋转；（ii）LSFL周期从与光束扫描方向平行的波纹的360±5nm逐渐变化到垂直于光束扫描形成的波纹的420±10nm。在LIPSS形成的表面等离子体激元模型框架内对所得结果进行了讨论。此外，还展示并讨论了纳米级摩擦行为的研究结果，该行为取决于LIPSS相对于AFM针尖扫描方向的取向。
