Polarisation-dependent generation of fs-laser induced periodic surface structures

Gräf, Stephan; Müller, Frank A.

doi:10.1016/j.apsusc.2015.01.056

Cited by 84 publications

(65 citation statements)

References 38 publications

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“…The pronounced ablation at scratches has been put in context of field enhancement as has been described recently . In contrast to LIPSS formation at femtosecond laser ablation,, we find no ordered (or lamellar) surface structuring. The surface rather develops splash and finger structures, the latter having a micrometer diameter and thus efficiently modifying light reflection.…”

Section: Resultssupporting

confidence: 64%

“…In particular, we find that corrugation here is on a micrometer scale, comparable to the laser wavelength. It is self‐organized in size and morphology by the laser‐surface interaction reminding of structure formation, for femtosecond laser pulses. Figure shows scanning electron microscope images of a Au target surface after a different number of applied shots of 1 mJ pulse energy.…”

Section: Resultsmentioning

confidence: 99%

“…The decreasing loss of laser energy due to an increased surface roughness can be correlated to an increased absorptance or decreased reflectance . This increase in absorptance can be referred to the formation of laser‐induced periodic surface structures (LIPSS) or ripples for ablation with femtosecond laser pulses ,. They can appear already within the first shots if the applied fluence is high enough ,.…”

Section: Introductionmentioning

confidence: 99%

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Incubation Effect of Pre‐Irradiation on Bubble Formation and Ablation in Laser Ablation in Liquids

et al. 2019

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Pulsed laser ablation in liquids (PLAL) is a multi‐scale process, which is widely studied either in batch ablation with prolonged target irradiation as well as mechanistic investigations, in a defined (single‐shot) process. However, fundamental studies on defined pulse series are rare. We have investigated the effect of a developing rough morphology of the target surface on the PLAL process with nanosecond pulses and, partially, picosecond pulses. At low fluence the cavitation bubble growth as well as the ablation yield depend on the irradiation history of the target. The bubble size increases with repeated irradiation on one spot for the first 2–30 pulses as well as with the applied dose. This is discussed within the framework of incubation effects. Incubation is found to be important, resulting in a bubble volume increase by a factor of six or more between pristine and corrugated targets. The target surface, changing from smooth to corrugated, induces a more efficient localization of laser energy at the solid‐liquid interface. This is accompanied by a suppressed reflectivity and more efficient coupling of energy into the laser‐induced plasma. Thus, the cavitation bubble size increases as well as ablation being enhanced. At high fluence, such incubation is masked by the rapid development of surface damage within the first shots, which eventually would lead to a reduction of bubble sizes.

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Section: Resultssupporting

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Incubation Effect of Pre‐Irradiation on Bubble Formation and Ablation in Laser Ablation in Liquids

et al. 2019

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“…Polarization effects are ubiquitous among earlier results on ablation, [ 29 ] nanoripple formation (including using relatively low NA = 0.1−0.25), [48][49][50] the growth of nanofl akes in solution, [ 25 ] and controlled melting of fi lms. [ 27 ] Elongation of fabricated features beyond the extent of the focal spot is clearly shown using short laser pulses.…”

Section: Communicationmentioning

confidence: 99%

Nanoscale Precision of 3D Polymerization via Polarization Control

Rekštytė

Jonavičius

Gailevičius

et al. 2016

Advanced Optical Materials

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COMMUNICATIONand as self-organized nanopatterns induced on a surface, [ 30 ] are among other polarization-related phenomena demonstrated recently.The infl uence of beam polarization orientation on laser processing has been thoroughly studied in the cases of conductive and dielectric solid targets. [ 31,32 ] There are known effects of polarization on the scalar parameters of laser-matter interaction, such as absorption coeffi cient and ionization rate. [33][34][35][36] It is also known that heat conduction fl ux (vector) in plasma might be dependent on the direction of the imposed fi eld. [ 37 ] In what follows, these effects are considered in succession: (i) accumulation from multiple pulses, (ii) effects of polarization under high-numerical aperture (NA) focusing, and (iii) the infl uence of the external high-frequency electric fi eld on electronic heat conduction. The latter contribution has not yet been considered in laser fabrication under tight focusing. All these photomodifi cation mechanisms occur simultaneously and affect polymerization, which takes approximately a millisecond for common photoresists [ 38 ] at a >90% voxel overlap at typical writing velocity of 100 µm s -1 for widespread laser 3D nanolithography. [ 39 ] In this paper, a systematic analysis via modeling and experiments is presented in order to reveal polarization effects, their infl uence on the feature size (resolution), and the coupling between thermal gradient and polarization in DLW.To study and demonstrate the polarization effects, 3D suspended resolution bridges at various angles, α , between the linear polarization and scanning direction were fabricated on a glass substrate ( Figure 1 inset in (a); see details in the Experimental Section). The line-width difference was 10%-20% (varying exposure) under typical polymerization conditions for the linearly polarized pulses. The largest width of a 3D bridge was observed when the scan direction was perpendicular to the orientation of linear polarization, α = π / 2 ( E ⊥ v s ). The heightto-width ratio of the suspended lines was dependent on the orientation of linear polarization and changed between 3.07 and 3.44; self-focusing was not present under our experimental conditions. [ 40 ] Detailed analysis of polarization, threshold, and heat accumulation effects, which are all important, are discussed next.For the experimental conditions used, the focal spot diameter (at 1/ e 2 ) can be calculated as d f = 1.22 λ /NA = 898 nm assuming, for simplicity, a Gaussian intensity profi le. However, at such tight focusing it is necessary to use the vectorial Debye theory (specifi cs [ 41 ] can be found in Section A, Supporting Information), which predicts an ellipsoidal focal spot with two lateral cross sections: W l = 790 nm and W s = 572 nm for long and short cross sections, respectively (or 500 and 360 nm at full width at half maximum (FWHM)) for the actual experimental

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“…For strong absorbing materials, such as most metals, low-spatial-frequency LIPSS (LSFL), also called ripples, are observed with a period generally slightly smaller than the laser wavelength293031. Additionally, it is generally accepted that the irradiation with linearly polarized beams causes LIPSS that are perpendicularly aligned to the incident electric field (E-field) vector3233. Therefore, rotating the laser polarization with optical retarders enables the generation of nanopatterns oriented preferentially to a determined specific direction.…”

mentioning

confidence: 99%

Surface micro- and nano-texturing of stainless steel by femtosecond laser for the control of cell migration

Martínez-Calderón

Manso‐Silván

Rodríguez

et al. 2016

Sci Rep

100

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The precise control over the interaction between cells and the surface of materials plays a crucial role in optimizing the integration of implanted biomaterials. In this regard, material surface with controlled topographic features at the micro- and nano-scales has been proved to affect the overall cell behavior and therefore the final osseointegration of implants. Within this context, femtosecond (fs) laser micro/nano machining technology was used in this work to modify the surface structure of stainless steel aiming at controlling cell adhesion and migration. The experimental results show that cells tend to attach and preferentially align to the laser-induced nanopatterns oriented in a specific direction. Accordingly, the laser-based fabrication method here described constitutes a simple, clean, and scalable technique which allows a precise control of the surface nano-patterning process and, subsequently, enables the control of cell adhesion, migration, and polarization. Moreover, since our surface-patterning approach does not involve any chemical treatments and is performed in a single step process, it could in principle be applied to most metallic materials.

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Polarisation-dependent generation of fs-laser induced periodic surface structures

Cited by 84 publications

References 38 publications

Incubation Effect of Pre‐Irradiation on Bubble Formation and Ablation in Laser Ablation in Liquids

Incubation Effect of Pre‐Irradiation on Bubble Formation and Ablation in Laser Ablation in Liquids

Nanoscale Precision of 3D Polymerization via Polarization Control

Surface micro- and nano-texturing of stainless steel by femtosecond laser for the control of cell migration

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