scholarly journals T-junction droplet generator realised in lithium niobate crystals by laser ablation

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
G. Pozza ◽  
S. Kroesen ◽  
G. Bettella ◽  
A. Zaltron ◽  
M. Esseling ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Lithium Niobate ◽  
Laser Pulse ◽  
Femtosecond Laser ◽  
Droplet Generator ◽  
Wide Range ◽  
Junction Geometry ◽  
Fluidic Circuits ◽  
Pulse Energies ◽  
Lithium Niobate Crystals

AbstractA femtosecond laser at 800 nm was used to create micro-fluidic circuits on lithium niobate (LiNbO3) substrates by means of laser ablation, using different scanning velocities (100-500 μm/s) and laser pulse energies (1-20 μJ). The T-junction geometry was exploited to create on y-cut LiNbO3 crystals a droplet generator, whose microfluidic performance was characterized in a wide range of droplet generation frequencies, from few Hz to about 1 kHz.

scholarly journals Effect of Laser Pulse Overlap and Scanning Line Overlap on Femtosecond Laser-Structured Ti6Al4V Surfaces

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 969 ◽  
Author(s):  
Georg Schnell ◽  
Ulrike Duenow ◽  
Hermann Seitz
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Surface Topography ◽  
Cell Attachment ◽  
Surface Structures ◽  
Laser Source ◽  
Laser Machining ◽  
Scanning Strategy ◽  
Wide Range ◽  
Scanning Line

Surface structuring is a key factor for the tailoring of proper cell attachment and the improvement of the bone-implant interface anchorage. Femtosecond laser machining is especially suited to the structuring of implants due to the possibility of creating surfaces with a wide variety of nano- and microstructures. To achieve a desired surface topography, different laser structuring parameters can be adjusted. The scanning strategy, or rather the laser pulse overlap and scanning line overlap, affect the surface topography in an essential way, which is demonstrated in this study. Ti6Al4V samples were structured using a 300 fs laser source with a wavelength of 1030 nm. Laser pulse overlap and scanning line overlap were varied between 40% and 90% over a wide range of fluences (F from 0.49 to 12.28 J/cm²), respectively. Four different main types of surface structures were obtained depending on the applied laser parameters: femtosecond laser-induced periodic surface structures (FLIPSS), micrometric ripples (MR), micro-craters, and pillared microstructures. It could also be demonstrated that the exceedance of the strong ablation threshold of Ti6Al4V strongly depends on the scanning strategy. The formation of microstructures can be achieved at lower levels of laser pulse overlap compared to the corresponding value of scanning line overlap due to higher heat accumulation in the irradiated area during laser machining.

Molecular Dynamics Study of Mechanism of Ablation Induced by a Femtosecond Laser Pulse

2003 ◽  
Author(s):  
Changrui Cheng ◽  
Xianfan Xu
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Laser Pulse ◽  
Femtosecond Laser ◽  
Critical Point ◽  
Change Process ◽  
Femtosecond Laser Ablation ◽  
Md Simulations ◽  
Femtosecond Laser Irradiation ◽  
Transient Temperature

In this work, molecular dynamics (MD) simulations are carried out to study femtosecond laser ablation of a metal, with an emphasis on the understanding of the mechanism of laser ablation. Theoretically, it has been shown that under intense femtosecond laser irradiation, the material can undergo a volumetric phase change process; its temperature can be close to or even above the critical point. MD simulations allow us to determine the transient temperature of the irradiated material as well as the transient thermodynamic state, which explain the mechanisms of femtosecond laser ablation.

Elemental Fractionation of Glass Using Laser Ablation Inductively Coupled Plasma Mass Spectrometry

1997 ◽  
Vol 51 (8) ◽  
pp. 1185-1192 ◽  
Author(s):  
Deborah Figg ◽  
Michael S. Kahr
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Melting Point ◽  
Laser Pulse ◽  
Inductively Coupled Plasma ◽  
Elemental Fractionation ◽  
Inductively Coupled ◽  
Analytical Results ◽  
Plasma Mass Spectrometry ◽  
Pulse Energies

Three laser wavelengths (1064, 532, and 266 nm) were employed for laser ablation at varied laser pulse energies to study the effect of irradiance and wavelength upon analytical results for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Two important results were observed and are reported here: (1) the intensity of the MS signal came to a local minimum when the laser focal point was on the sample surface, and (2) elemental fractionation based upon laser wavelength and laser pulse energy was observed. For the waste glass simulant studied, ablation with 1064-nm (IR) and 532-nm (green) radiation produced elemental fractionation that relates to the melting point of the elemental oxide, whereas with 266-nm (UV) ablation the response was independent of the elemental oxide melting point. At high laser powers, ablation at 266 nm produced an elemental bias based upon the mass of the elements. These observations suggest the use of ultraviolet radiation at low pulse energies to obtain improved analytical results.

Spatial Modulation of Linear and Quadratic Susceptibilities in Lithium Niobate Crystals by Using Femtosecond Laser Pulses

2006 ◽  
Vol 333 (1) ◽  
pp. 151-156
Author(s):  
G. A. Torchia ◽  
C. Méndez ◽  
J. R. Vázquez De Aldana ◽  
D. Delgado ◽  
I. Arias ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Spatial Modulation ◽  
Lithium Niobate Crystals

scholarly journals Laser-induced ablation of tantalum in a wide range of pulse durations

2020 ◽  
Vol 126 (9) ◽  
Author(s):  
Steffen Mittelmann ◽  
Jannis Oelmann ◽  
Sebastijan Brezinsek ◽  
Ding Wu ◽  
Hongbin Ding ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Laser Pulse ◽  
Femtosecond Laser ◽  
Pulse Duration ◽  
Laser Fluence ◽  
Crater Depth ◽  
Nanosecond Laser ◽  
Threshold Fluence ◽  
Wide Range ◽  
Laser Systems

Abstract We present data and analysis of the laser-induced ablation of pure tantalum (Ta, $$Z=73$$ Z = 73 ). We have identified different physical regimes using a wide range of laser pulse durations. A comparison of the influence of strongly varying laser pulse parameters on high-Z materials is presented. The crater depth caused by three different laser systems of pulse duration $${\varDelta }\tau _1=5\,\mathrm {ns}$$ Δ τ 1 = 5 ns and wavelength $$\lambda _1=1064\,\mathrm {nm}$$ λ 1 = 1064 nm , $${\varDelta }\tau _2=35\,\mathrm {ps}$$ Δ τ 2 = 35 ps , $$\lambda _2=355\,\mathrm {nm}$$ λ 2 = 355 nm and $${\varDelta }\tau _3=8.5\,\mathrm {fs}$$ Δ τ 3 = 8.5 fs , $$\lambda _3=790\,\mathrm {nm}$$ λ 3 = 790 nm are analyzed via confocal microscopy as a function of laser fluence and intensity. The minimum laser fluence needed for ablation, called threshold fluence, decreases with shorter pulse duration from $$1.10\,\mathrm {J/cm}^2$$ 1.10 J / cm 2 for the nanosecond laser to $$0.17\,\mathrm {J/cm}^2$$ 0.17 J / cm 2 for the femtosecond laser.

Optical investigation of femtosecond laser induced microstress in neodymium doped lithium niobate crystals

2006 ◽  
Vol 100 (3) ◽  
pp. 033521 ◽  
Author(s):  
A. Ródenas ◽  
J. A. Sanz García ◽  
D. Jaque ◽  
G. A. Torchia ◽  
C. Mendez ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Femtosecond Laser ◽  
Optical Investigation ◽  
Lithium Niobate Crystals
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