scholarly journals Numerical Investigation on the Influence of Water Vapor Ionization on the Dynamic and Energy Deposition of Femtosecond Ultraviolet Laser Filamentation in Air

2019 ◽  
Vol 9 (20) ◽  
pp. 4201
Author(s):  
Qingwei Zeng ◽  
Lei Liu ◽  
Kejin Zhang ◽  
Shuai Hu ◽  
Taichang Gao ◽  
...  
Keyword(s):  
Water Vapor ◽  
Energy Deposition ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Nonlinear Propagation ◽  
High Humidity ◽  
Atmospheric Conditions ◽  
Energy Increase ◽  
Influence Of Water ◽  
Vapor Ionization

The effects of water vapor ionization on the nonlinear propagation of femtosecond laser pulses with a 248 nm wavelength are numerically investigated in this paper. It is found that ionization of H2O molecules plays a significant role in air ionization, which seriously affects the dynamic and energy deposition of filamentation. The propagation of femtosecond pulses in air with different humidity levels are compared. The total number of electrons and total deposited pulse energy increase with the humidity increases. However, they tend to be saturated in high humidity conditions. Results presented here are conducive to characterizing the long-range propagation of filaments under atmospheric conditions.

Study on the height distribution of atmospheric nonlinear refractive index with a theoretical calculation model

2018 ◽  
Vol 27 (04) ◽  
pp. 1850044
Author(s):  
QingWei Zeng ◽  
Lei Liu ◽  
TaiChang Gao ◽  
Ming Chen ◽  
Qi Wang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Lower Atmosphere ◽  
Nonlinear Propagation ◽  
Accurate Estimation ◽  
Height Distribution ◽  
Long Distance

The crucial role of nonlinear propagation effects in the self-guiding of femtosecond laser pulses required accurate representation of nonlinearities to describe them. In this paper, an improved theoretical model has been proposed to study the height distribution of the atmospheric nonlinear refractive index. The results show that the revised model obviously improves accurate estimation of nonlinear index at the long wavelength band. Based on the model, we also found the atmospheric nonlinear refractive index differs much from the lower atmosphere to the upper atmosphere. Our results are essential for engineering applications based on the long-distance ultrashort laser pulses’ transmission in diverse atmosphere.

Nonlinear propagation of femtosecond laser pulses in dielectrics

2003 ◽  
Author(s):  
Piotr Wasylczyk ◽  
Wojciech Wasilewski ◽  
Michal Matuszewski ◽  
Marek Trippenbach ◽  
Czeslaw Radzewicz
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Nonlinear Propagation

Controlled energy deposition and void-like modification inside transparent solids by two-color tightly focused femtosecond laser pulses

2017 ◽  
Vol 110 (16) ◽  
pp. 163903 ◽  
Author(s):  
Fedor Potemkin ◽  
Evgeniy Mareev ◽  
Yulia Bezsudnova ◽  
Victor Platonenko ◽  
Boris Bravy ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Energy Deposition ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses

Nonlinear Propagation of Intense Femtosecond Laser Pulses in a Foggy and Cloudy Environment

2020 ◽  
Vol 40 (15) ◽  
pp. 1519001
Author(s):  
曾庆伟 Zeng Qingwei ◽  
刘磊 Liu Lei ◽  
胡帅 Hu Shuai ◽  
张克瑾 Zhang Kejin ◽  
艾凯 Ai Kai ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Nonlinear Propagation

Nonlinear energy deposition of filamentation with femtosecond Airy laser beams in water

2019 ◽  
Vol 33 (28) ◽  
pp. 1950339
Author(s):  
Qingwei Zeng ◽  
Lei Liu ◽  
Kejin Zhang ◽  
Taichang Gao ◽  
Ming Chen ◽  
...  
Keyword(s):  
Pulse Duration ◽  
Energy Deposition ◽  
Spatial Dynamics ◽  
Beam Waist ◽  
Nonlinear Propagation ◽  
Laser Beams ◽  
Energy Increase ◽  
Deposited Energy ◽  
Temporal And Spatial ◽  
Nonlinear Energy

The nonlinear propagation of femtosecond Airy laser filaments in water is numerically investigated in this paper. We mainly consider the influences of confinement parameter, pulse duration and beam waist on the deposited energy of filaments. The values of confinement parameter are found to have a significant impact on the temporal and spatial dynamics of the pulse. The characteristics of energy deposition also differ widely for Airy beams with different confinement parameters. The less the confinement parameter, the more energy deposited by filamentation. However, the relative deposited energy evolves relatively small changes under different confinement parameters. We also found the longer pulse duration and longer beam waist are beneficial to the total deposited energy increase.

scholarly journals Improving Fatigue Performance of Laser-Welded 2024-T3 Aluminum Alloy Using Dry Laser Peening

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1192 ◽  
Author(s):  
Sano ◽  
Eimura ◽  
Hirose ◽  
Kawahito ◽  
Katayama ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Weld Metal ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Fatigue Performance ◽  
Laser Peening ◽  
Residual Tensile Stress ◽  
Atmospheric Conditions ◽  
2024 Aluminum Alloy ◽  
Welding Defects

The purpose of the present study was to verify the effectiveness of dry laser peening (DryLP), which is the peening technique without a sacrificial overlay under atmospheric conditions using femtosecond laser pulses on the mechanical properties such as hardness, residual stress, and fatigue performance of laser-welded 2024 aluminum alloy containing welding defects such as undercuts and blowholes. After DryLP treatment of the laser-welded 2024 aluminum alloy, the softened weld metal recovered to the original hardness of base metal, while residual tensile stress in the weld metal and heat-affected zone changed to compressive stresses. As a result, DryLP treatment improved the fatigue performances of welded specimens with and without the weld reinforcement almost equally. The fatigue life almost doubled at a stress amplitude of 180 MPa and increased by a factor of more than 50 at 120 MPa. DryLP was found to be more effective for improving the fatigue performance of laser-welded aluminum specimens with welding defects at lower stress amplitudes, as stress concentration at the defects did not significantly influence the fatigue performance.

Kilometer-range nonlinear propagation of femtosecond laser pulses

2004 ◽  
Vol 69 (3) ◽  
Author(s):  
Miguel Rodriguez ◽  
Riad Bourayou ◽  
Guillaume Méjean ◽  
Jérôme Kasparian ◽  
Jin Yu ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Nonlinear Propagation
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