Comparison of numerical simulations with experimental results of the atmospheric self-focusing propagation of femtosecond laser pulses

2003 ◽  
Author(s):  
T.S. Luk ◽  
P.M. Bennett ◽  
A.C. Bernstein ◽  
A. McPherson ◽  
T.R. Nelson ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Numerical Simulations ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Experimental Results ◽  
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

In-Fiber Mach-Zehnder Interferometer Fabricated by Femtosecond Laser

2013 ◽  
Vol 658 ◽  
pp. 232-236
Author(s):  
Zhi Long Ou ◽  
Yong Qin Yu ◽  
Jia Rong Zheng ◽  
Ji Shun Wang ◽  
Xue Chen ◽  
...  
Keyword(s):  
Refractive Index ◽  
Femtosecond Laser ◽  
Repetition Rate ◽  
Laser Pulses ◽  
Resonance Wavelength ◽  
Femtosecond Laser Pulses ◽  
Experimental Results ◽  
Spatial Period ◽  
Core Mode ◽  
Cladding Mode

We have demonstrated several MZIs based on two spaced 3-dB LPFGs with different interference lengths in conventional SMFs fabricated in air by femtosecond laser pulses with the duration of 200 fs and the repetition rate of 250 kHz. Experimental results show that the average fringe spatial period increases with the resonance wavelength, while decreases with the interference length in approximately inverse proportion. The dominant cladding mode interfering with core mode has been calculated. The MZI sensitivity on temperature, refractive index and strain with a length of 16mm has also been investigated.

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