Experiment study of wide range tunable femto-nano joule laser pulse output with flat top profile

2018 ◽  
Author(s):  
jianguo Xin ◽  
yuchen Song ◽  
teng Sun ◽  
yunfeng Chen
Keyword(s):  
Laser Pulse ◽  
Experiment Study ◽  
Wide Range ◽  
Pulse Output

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.

scholarly journals Single-axial-mode Nd:YAG laser with precisely controllable laser pulse output time

2019 ◽  
Vol 68 (13) ◽  
pp. 134202
Author(s):  
Shu-Tao Dai ◽  
Tao Jiang ◽  
Li-Xia Wu ◽  
Hong-Chun Wu ◽  
Wen-Xiong Lin
Keyword(s):  
Laser Pulse ◽  
Nd:Yag Laser ◽  
Axial Mode ◽  
Output Time ◽  
Pulse Output

scholarly journals Динамика спинорной экситон-поляритонной системы в латерально сжатых GaAs микрорезонаторах при резонансном фотовозбуждении

2018 ◽  
Vol 60 (8) ◽  
pp. 1567
Author(s):  
А.А. Деменев ◽  
Н.А. Гиппиус ◽  
В.Д. Кулаковский
Keyword(s):  
Laser Pulse ◽  
Spatial Coherence ◽  
Picosecond Laser ◽  
Threshold Value ◽  
Laser Pulses ◽  
Josephson Effects ◽  
High Q ◽  
Wide Range ◽  
Linearly Polarized ◽  
Polariton Branch

AbstractThe evolution of the spatial coherence and the polarization has been studied in a freely decaying polariton condensate that is resonantly excited by linearly polarized picosecond laser pulses at the lower and upper sublevels of the lower polariton branch in a high-Q GaAs-based microcavity with a reduced lateral symmetry without excitation of the exciton reservoir. It is found that the condensate inherits the coherence of the exciting laser pulse at both sublevels in a wide range of excitation densities and retains it for several dozen picoseconds. The linear polarization of the photoexcited condensate is retained only in the condensate at the lower sublevel. The linearly polarized condensate excited at the upper sublevel loses its stability at the excitation densities higher a threshold value: it enters a regime of internal Josephson oscillations with strongly oscillating circular and diagonal linear degrees of polarization. The polariton–polariton interaction leads to the nonlinear Josephson effects at high condensate densities. All the effects are well described in terms of the spinor Gross–Pitaevskii equations. The cause of the polarization instability of the condensate is shown to be the spin anisotropy of the polariton–polariton interaction.

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.

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.

Influence of Wavefront Distortion on Spatial-Temporal Property of Laser Pulse Output by Grating Compressor

2018 ◽  
Vol 45 (4) ◽  
pp. 0401011
Author(s):  
张森 Zhang Sen ◽  
张军伟 Zhang Junwei ◽  
周忆 Zhou Yi ◽  
王逍 Wang Xiao ◽  
邓波 Deng Bo ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Temporal Property ◽  
Wavefront Distortion ◽  
Pulse Output

Experiment Study on Nd: YAG Pulsed Laser Cutting Carbon Fibers Composites

2011 ◽  
Vol 464 ◽  
pp. 510-513
Author(s):  
Tao Ge ◽  
Yong Kang Zhang ◽  
Xiao Meng Chu
Keyword(s):  
Laser Pulse ◽  
Carbon Fibers ◽  
Laser Cutting ◽  
Epoxy Resins ◽  
Laser Pulse Energy ◽  
Cutting Speed ◽  
Pulsed Laser ◽  
Evaluation Index ◽  
Experiment Study

Nd:YAG pulsed laser cutting carbon fibers reinforced epoxy resins composites was studied. HAZ and kerf width was made as evaluation index, as well as laser pulse energy, cutting speed, pulse duration and assistant gas pressure was made as controlled parameters. Ideal quality of cutting can be achieved by adjusting those parameters. The effect of each parameter was analyzed.

Raman Studies of Carrier Activation in Laser Annealed GaAs Capped with Silicon Nitride

1986 ◽  
Vol 74 ◽  
Author(s):  
A. Compaan ◽  
S. C. Abbi ◽  
H. D. Yao ◽  
A. Bhat ◽  
F. Hashmi
Keyword(s):  
Silicon Nitride ◽  
Laser Pulse ◽  
Raman Scattering ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Dye Laser ◽  
Pulsed Laser Annealing ◽  
Wide Range ◽  
Xecl Excimer Laser

AbstractCarrier concentrations exceeding 1019/cm3 in GaAs implanted with Si (2 × 1014/cm2 @ 140 keV) have been obtained by pulsed laser annealing with either a dye laser (λ = 728 nm) or a XeCl excimer laser (λ = 308 nm). Carrier concentrations were measured by plasmon Raman scattering over a wide range of anneal energy densities. Compared with capless laser annealing, much higher carrier activations were achieved when the annealing laser pulse was incident through a Si3N4 cap.

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