The Interactions of Microhole Sidewall With Plasma induced by Femtosecond Laser Ablation in High-Aspect-Ratio Microholes

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Benxin Wu ◽  
Sha Tao ◽  
Shuting Lei
Keyword(s):  
Laser Ablation ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Material Removal ◽  
Laser Energy ◽  
Spatial Scales ◽  
Femtosecond Laser Ablation ◽  
Plasma Energy ◽  
Direct Laser ◽  
Fs Laser

High-aspect-ratio microholes have many important applications, but their drilling is very challenging. Femtosecond (fs) laser ablation provides a potential solution, but involves many complicated physical processes that have not been well understood, which have hindered its practical application. One of these is that the plasma induced by laser ablation at the hole bottom will transfer some of its energy to the hole sidewall as it expands in the microhole. The plasma–sidewall interaction has been rarely studied in literature, and it is still not clear if or not the energy transferred from the plasma is sufficient to cause significant material removal from the sidewall. Direct time-resolved observations are extremely difficult due to the small temporal/spatial scales and the spatial constraint inside the hole, while the sidewall characterization after laser ablation is difficult to distinguish between the possible material removal due to plasma energy transfer and that due to direct laser energy absorption by the sidewall. In this paper, a physics-based model is applied as the investigation tool to study the plasma–sidewall interaction in fs laser drilling of high-aspect-ratio microholes. It has been found that for the studied conditions the energy transferred from the plasma is not sufficient to cause significant material removal from the sidewall through any thermally induced phase change process.

Fabrication of high-aspect-ratio grooves with high surface quality by using femtosecond laser

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ru Zhang ◽  
Chuanzhen Huang ◽  
Jun Wang ◽  
Hongtao Zhu ◽  
Hanlian Liu
Keyword(s):  
Laser Ablation ◽  
Aspect Ratio ◽  
Femtosecond Laser ◽  
Process Parameters ◽  
Laser Fluence ◽  
High Aspect Ratio ◽  
High Surface ◽  
Content Type ◽  
High Surface Quality ◽  
Fs Laser

Purpose The purpose of this study is to fabricate high-aspect-ratio grooves with high surface quality by femtosecond laser (FS) to improve the machinability of silicon carbide (SiC) and optimize the process parameters in micromechanical applications. Design/methodology/approach Four contrast experiments are reported to characterize the FS laser grooving process for SiC with polarization direction, crystal orientation, multi-pass scanning and z layer feed, respectively. The effects of different experimental conditions on the groove characteristics, material removal rate (MRR), aspect ratio, heat affected zone (HAZ) and surface roughness Ra are analyzed. Findings The influence of increasing laser fluence and multi-scanning pass on the groove depth is greater than on the groove width. The MRR, aspect ratio, HAZ and Ra increased with the increase of laser fluence and multi-scanning pass. The direction of laser polarization affects the direction of hot electron injection but has little effect on the material characteristics. FS laser ablation is an isotropic process and there is no obvious change in different crystal orientations. The z-layer feed can significantly increase the groove width and depth and reduce HAZ and Ra. The maximum aspect ratio of 82.67% was fabricated. Originality/value The results contribute to the understanding of the removal mechanism and reduce the friction of the microfluidic device and improve the flowability in the FS laser ablation of SiC. This paper provides suggestions for the selection of suitable process parameters and provides a wider possibility for the application of micro-texture on SiC.

Pressure Waves in Microscopic Simulations of Laser Ablation Leonid

1998 ◽  
Vol 538 ◽  
Author(s):  
V. Zhigilei ◽  
Barbara J. Garrison
Keyword(s):  
Boundary Condition ◽  
Laser Ablation ◽  
Laser Energy ◽  
Scale Up ◽  
Boundary Region ◽  
Dynamics Simulation ◽  
Pressure Waves ◽  
Absorption Region ◽  
Organic Solids ◽  
Direct Laser

AbstractLaser ablation of organic solids is a complex collective phenomenon that includes processes occurring at different length and time scales. A mesoscopic breathing sphere model developed recently for molecular dynamics simulation of laser ablation and damage of organic solids has significantly expanded the length-scale (up to hundreds of nanometers) and the time-scale (up to nanoseconds) of the simulations. The laser induced buildup of a high pressure within the absorbing volume and generation of the pressure waves propagating from the absorption region poses an additional challenge for molecular-level simulation. A new dynamic boundary condition is developed to minimize the effects of the reflection of the wave from the boundary of the computational cell. The boundary condition accounts for the laser induced pressure wave propagation as well as the direct laser energy deposition in the boundary region.

Optimization of laser energy deposition for single-shot high aspect-ratio microstructuring of thick BK7 glass

2016 ◽  
Vol 120 (1) ◽  
pp. 013102 ◽  
Author(s):  
Valerio Garzillo ◽  
Vytautas Jukna ◽  
Arnaud Couairon ◽  
Robertas Grigutis ◽  
Paolo Di Trapani ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Energy Deposition ◽  
Laser Energy ◽  
Single Shot ◽  
Bk7 Glass

One-Step Fabrication and Functionalization of Nanostructured Silicon Surfaces for Advanced Sensing Applications

2020 ◽  
Vol 312 ◽  
pp. 154-159
Author(s):  
Alexander Yuryevich Mironenko ◽  
Mikhail Tutov ◽  
Alexander Konstantinovich Chepak ◽  
Eugeny Mitsai ◽  
Alexander A. Sergeev ◽  
...  
Keyword(s):  
Laser Processing ◽  
Laser Energy ◽  
High Spatial Frequency ◽  
Laser Pulses ◽  
Successful Implementation ◽  
Experimental Conditions ◽  
Sensing Applications ◽  
Direct Laser ◽  
Fs Laser ◽  
One Step

Direct laser processing of various materials with nano- and femtosecond (fs) laser pulses is known to be a facile and inexpensive technology for fabrication of various surface morphologies. Since ultrafast deposition of the laser energy to target material typically creates unique experimental conditions with extremely high pressure and temperature, we hypothesized that carrying out this process in anhydrous non-oxidizing environment containing functionalizing agent (fluorophore with vinyl functional group) will allow one-step fabrication and subsequent functionalization of the surface of high-n material. In this paper, we demonstrate successful implementation of this idea by fabricating high-spatial-frequency laser-induced periodic surface structures (LIPSS) via direct fs-pulse ablation of bulk crystalline Si wafer immersed in solution of N-vinylcarbazole in toluene. Laser processing with linearly polarized fs-laser pulses was found to produce LIPSS with a characteristic period around 100 nm functionalized with N-vinylcarbazole molecules via photo-activated hydrosililation reaction. The unique LIPSS with hierarchical roughness and remarkable light trapping performance functionalized with sensory fluorophore show high sensitivity due to implementation of surface enhanced fluorescence effect. By using N-vinylcarbazole as functionalizing agent we demonstrate one-step fabrication of high-performance sensor for detecting nitrobenzene in water with a detection limit of 40 nM.

scholarly journals Laser ablation of high-aspect-ratio hole arrays in tungsten for X-ray applications

2019 ◽  
Vol 209 ◽  
pp. 60-65 ◽  
Author(s):  
Chantal M. Silvestre ◽  
Jens H. Hemmingsen ◽  
Erik S. Dreier ◽  
Jan Kehres ◽  
Ole Hansen
Keyword(s):  
Laser Ablation ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
X Ray ◽  
Hole Arrays
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