Simulation of femtosecond laser pulses self-focusing with normal dispersion in air by the method of diffraction-beam tubes

2019 ◽  
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Normal Dispersion ◽  
Self Focusing

Study on spatiotemporal evolution of chirped femtosecond laser pulses at specific spatial position during small-scale self-focusing

Optik ◽  
2018 ◽  
Vol 155 ◽  
pp. 97-104
Author(s):  
Yangbao Deng ◽  
Shuguang Deng ◽  
Chao Tan ◽  
Cuixiu Xiong ◽  
Guangfu Zhang ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Spatial Position ◽  
Small Scale ◽  
Spatiotemporal Evolution ◽  
Self Focusing

scholarly journals Remote Detection of Uranium Using Self-Focusing Intense Femtosecond Laser Pulses

2020 ◽  
Vol 12 (8) ◽  
pp. 1281 ◽  
Author(s):  
Miloš Burger ◽  
Patrick J. Skrodzki ◽  
Lauren A. Finney ◽  
John Nees ◽  
Igor Jovanovic
Keyword(s):  
Femtosecond Laser ◽  
Optical Measurement ◽  
Measurement Techniques ◽  
Radiation Detection ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ablation Efficiency ◽  
Emission Signal ◽  
Self Focusing ◽  
Spectroscopic Signatures

Optical measurement techniques can address certain important challenges associated with nuclear safety and security. Detection of uranium over long distances presents one such challenge that is difficult to realize with traditional ionizing radiation detection, but may benefit from the use of techniques based on intense femtosecond laser pulses. When a high-power laser pulse propagates in air, it experiences collapse and confinement into filaments over an extended distance even without external focusing. In our experiments, we varied the initial pulse chirp to optimize the emission signal from the laser-produced uranium plasma at an extended distance. While the ablation efficiency of filaments formed by self-focusing is known to be significantly lower when compared to filaments produced by external focusing, we show that filaments formed by self-focusing can still generate luminous spectroscopic signatures of uranium detectable within seconds over a 10-m range. The intensity of uranium emission varies periodically with laser chirp, which is attributed to the interplay among self-focusing, defocusing, and multi-filament fragmentation along the beam propagation axis. Grouping of multi-filaments incident on target is found to be correlated with the uranium emission intensity. The results show promise towards long-range detection, advancing the diagnostics and analytical capabilities in ultrafast laser-based spectroscopy of high-Z elements.

Onset of nonlinear self-focusing of femtosecond laser pulses in air: Conventional vs spatiotemporal focusing

2015 ◽  
Vol 92 (2) ◽  
Author(s):  
Ya Cheng ◽  
Hongqiang Xie ◽  
Zhaohui Wang ◽  
Guihua Li ◽  
Bin Zeng ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Self Focusing

scholarly journals Waveguide structures in heavy metal oxide glass written with femtosecond laser pulses above the critical self-focusing threshold

2005 ◽  
Vol 86 (12) ◽  
pp. 121109 ◽  
Author(s):  
J. Siegel ◽  
J. M. Fernández-Navarro ◽  
A. García-Navarro ◽  
V. Diez-Blanco ◽  
O. Sanz ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Femtosecond Laser ◽  
Metal Oxide ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Oxide Glass ◽  
Self Focusing

Self-focusing and Filamentation of Powerful Femtosecond Laser Pulses

2008 ◽  
pp. 371-398
Author(s):  
V.P. Kandidov ◽  
A. E. Dormidonov ◽  
O.G. Kosareva ◽  
S.L. Chin ◽  
W. Liu
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Self Focusing

scholarly journals Diffraction-ray optics of femtosecond laser pulses under normal dispersion conditions in air

2020 ◽  
pp. 157-164
Author(s):  
Y.E. Geints ◽  
◽  
A.A. Zemlyanov ◽  
O.V. Minina ◽  
◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Numerical Solutions ◽  
Group Velocity Dispersion ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Beam Radius ◽  
Normal Dispersion ◽  
Beam Tube ◽  
Rayleigh Length ◽  
Nonlinear Focus

The results of a theoretical study of the propagation of femtosecond pulses of a Ti:Sa laser under normal dispersion conditions in air are presented. The use of the diffraction-beam tube method for the analysis of numerical solutions of the nonlinear Schrödinger equation in a dispersion medium with Kerr-plasma nonlinearity made it possible to determine the basic regularities of femtosecond laser pulses self-focusing and filamentation in air at various pulse lengths, initial beam radius, and peak powers. It is shown that in the case of the group velocity dispersion influence with an increase in the initial laser beam radius, the filamentation breaks down even at large supercritical powers. It is shown that with an increase in the dispersion distortions of the pulse the radius of the energetically replenishing diffraction beam tube, the angular divergence of the post-filamentation light channel, and the nonlinear focus coordinate normalized to the Rayleigh length for the central time layers of the laser pulse and the integral picture are increasing.

Effect of Power Saturation on Spectrum Expanding in Normal Dispersion Region of Microstructured Fiber by Femtosecond Laser Pulses

2008 ◽  
Vol 35 (7) ◽  
pp. 1041-1044 ◽  
Author(s):  
李曙光 Li Shuguang ◽  
程同蕾 Cheng Tonglei ◽  
张焕平 Zhang Huanping ◽  
侯蓝田 Hou Lantian
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Microstructured Fiber ◽  
Normal Dispersion ◽  
Dispersion Region
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