Non-diffraction-length Bessel-beam femtosecond laser drilling of high-aspect-ratio microholes in PMMA

Optimization mechanism and applications of ultrafast laser machining towards highly designable 3D micro/nano structuring

“…91,92 In addition to alloys, ultrafast laser drilling can be performed on polymers, ceramics, glass and other materials. 82,[93][94][95][96] Liu and co-workers fabricated an all-silicon uniform-aligned concave MLA through dry-etching-assisted femtosecond laser machining. 34 Jiao et al proposed a new method for applying a direct current to a silicon substrate during picosecond laser drilling.…”

“…98 Incredibly, Wang and co-workers processed holes on PMMA. 94 In this study, an axial-hole lens with different cone angles was used to transform the incident Gaussian beam into a Bessel beam with different non-diffraction lengths and focus on the sample for processing. The aspect ratio of micropores was enhanced by increasing the pulse number and the cone angle of the axial cone lens.…”

“…This method achieved the maximum ratio of depth to diameter of micropores (348 : 1). 94 In addition, ultrafast laser processing of porous has a selfcleaning effect, that is, the molten spatter aer ultrafast laser etching is removed with continuous laser irradiation. Zhao et al studied surface morphology and internal morphology based on the self-cleaning effect (Fig.…”

“…4(f) ). 94 These liquids include water, cetane, lake water, ink, glycerin, coffee, milk, egg whites and egg yolks. 94 In 2018, Yong and co-workers employed one-step FLDW to prepare porous network microstructures on the surface of various polymers.…”

“… 94 These liquids include water, cetane, lake water, ink, glycerin, coffee, milk, egg whites and egg yolks. 94 In 2018, Yong and co-workers employed one-step FLDW to prepare porous network microstructures on the surface of various polymers. 93 They also found that the growth of C6 glioma cells was promoted by the original laser-induced porous PET surface as a culture substrate, while the smooth surface of PET completely inhibited the growth of C6 glioma cells.…”