Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7129424 | Optics & Laser Technology | 2018 | 7 Pages |
Abstract
Laser-induced periodic surface structures (LIPSS) are studied on germanium surface in air by the femtosecond pulsed laser with repetition frequency of 76â¯MHz and wavelength λ of 800â¯nm. Three types of LIPSS were found and they are low-spatial-frequency LIPSS (LSFL), high-spatial-frequency LIPSS (HSFL), and LSFL superimposed with HSFL. The period ÎLSFL of LSFL shrinks quickly from approximately 650â¯nm to 400â¯nm (â¼Î»/2) when lowering the scanning speed. Comparatively, the period ÎHSFL of HSFL keeps almost constant between 90 and 100â¯nm (â¼Î»/8) when the scanning speed and the laser pulse energy vary. LSFL and HSFL coexist when the laser pulse energy is around 3.3â¯nJ/pulse and the scanning speed ranges between 3 and 8â¯mm/s. The surface plasmon polariton waves make a contribution to the formation of LIPSS and the fourth harmonic generation (FHG) might be involved in the formation of HSFL.
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Authors
Xiaoming Lin, Xiaohong Li, Yanbin Zhang, Changxin Xie, Kaijun Liu, Qiang Zhou,