Acta Photonica Sinica, Volume. 52, Issue 7, 0752301(2023)
High Quality Near-subwavelength Ripples on Si Induced by Femtosecond Pulse Train Output from Fabry-Perot Cavity(Invited)
Laser-Induced Periodic Surface Structures (LIPSS) can be widely used in different processing fields, involving various materials such as semiconductors, dielectrics, metals, polymers. They have great potential in micro-nano processing. LIPSS are divided into two categories: Near-Subwavelength Ripples (NSRs) with period Λ larger than λ/2 and Deep-Subwavelength Ripples (DSRs) with period Λ smaller than λ/2, where λ is the incident laser wavelength. LIPSS can improve the surface properties of materials and can be used for modulation of the surface wettability of materials; enhanced surface Raman scattering; surface coloring; birefringence and optical storage, etc. They can be widely applied in many fields such as data storage, industrial manufacturing, and biomedicine.The formation of LIPSS is a complex process. Within a few nanoseconds after the femtosecond laser irradiation on the material surface, a series of ultrafast processes such as carrier excitation, carrier heating, lattice heating, plasma ejection, and nanoparticle ejection occur, which greatly increases the difficulty of processing regular NSRs. Therefore, how to improve the quality of NSRs has been an important research direction for femtosecond laser processing.Pulse shaping can regulate the distribution of laser energy in the time domain, which can then regulate the ultrafast process of laser-matter interaction. In order to fabricate high-quality LIPSS, we built a Fabry-Perot (F-P) cavity femtosecond laser pulse train processing system to conduct femtosecond laser time-domain shaping. The central wavelength of the laser is 1 030 nm, and we output femtosecond laser pulse train with flexible sub-pulse intervals in the range of 1~300 ps to fabricate NSRs on the silicon surface. The laser scanning velocity is altered by moving the sample through a 3D electronically controlled translation stage. By adjusting the distance between beam splitter and zero-degree mirror, we changed the sub-pulse interval and investigated NSRs induced by pulse trains with different sub-pulse intervals.After the samples were processed, we tested the surface morphology of the samples using a Scanning Electron Microscope (SEM). The NSRs induced by a Gaussian laser were slightly curved and had rough edges. However, the NSRs induced by the shaped pulse with a sub-pulse interval of 100 ps were uniformly oriented with smooth and straight edges. The peak of the spectrum obtained by its Fourier transform was (0.992±0.008)
Get Citation
Copy Citation Text
Yufeng XU, Yuchan ZHANG, Qilin JIANG, Huihui SHEN, Tianqing JIA. High Quality Near-subwavelength Ripples on Si Induced by Femtosecond Pulse Train Output from Fabry-Perot Cavity(Invited)[J]. Acta Photonica Sinica, 2023, 52(7): 0752301
Category:
Received: Apr. 10, 2023
Accepted: May. 16, 2023
Published Online: Sep. 26, 2023
The Author Email: ZHANG Yuchan (yczhang@lps.ecnu.edu.cn), JIA Tianqing (tqjia@phy.ecnu.edu.cn)