Beam width measurements of asymmetric multi-mode laser beams

1999 ◽  
Vol 31 (6) ◽  
pp. 411-418 ◽  
Author(s):  
D. Diso ◽  
M.R. Perrone ◽  
M.L. Protopapa
Pramana ◽  
1999 ◽  
Vol 53 (2) ◽  
pp. 307-319 ◽  
Author(s):  
Rakesh Kapoor ◽  
PK Mukhopadhyay ◽  
Jogy George ◽  
SK Sharma

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Manzoor Ahmad Wani ◽  
Niti Kant

Self-focusing of Hermite-Cosh-Gaussian (HChG) laser beam in plasma under density transition has been discussed here. The field distribution in the medium is expressed in terms of beam-width parameters and decentered parameter. The differential equations for the beam-width parameters are established by a parabolic wave equation approach under paraxial approximation. To overcome the defocusing, localized upward plasma density ramp is considered, so that the laser beam is focused on a small spot size. Plasma density ramp plays an important role in reducing the defocusing effect and maintaining the focal spot size up to several Rayleigh lengths. To discuss the nature of self-focusing, the behaviour of beam-width parameters with dimensionless distance of propagation for various values of decentered parameters is examined by numerical estimates. The results are presented graphically and the effect of plasma density ramp and decentered parameter on self-focusing of the beams has been discussed.


1978 ◽  
Vol 24 (1) ◽  
pp. 11-15 ◽  
Author(s):  
W. Brunner ◽  
H. Paul
Keyword(s):  

1981 ◽  
Vol 20 (10) ◽  
pp. 1728 ◽  
Author(s):  
James T. Luxon ◽  
David E. Parker

2010 ◽  
Vol 22 (6) ◽  
pp. 1229-1233
Author(s):  
葛廷武 Ge Tingwu ◽  
陆丹 Lu Dan ◽  
伍剑 Wu Jian ◽  
徐坤 Xu Kun ◽  
林金桐 Lin Jintong
Keyword(s):  

2016 ◽  
Vol 119 ◽  
pp. 06005 ◽  
Author(s):  
Pablo Ristori ◽  
Lidia Otero ◽  
Yoshitaka Jin ◽  
Nobuo Sugimoto ◽  
Tomoaki Nishizawa ◽  
...  

1992 ◽  
Vol 01 (02) ◽  
pp. 421-430 ◽  
Author(s):  
ESA JAATINEN ◽  
BARRY LUTHER-DAVIES

We report experiments on the use of a semilinear phase-conjugate mirror to transfer single-mode laser beams through distorting media. Calculations using a 1-D model show that in optimum circumstances, up to 90% of the input power can be transferred to the system output whilst experimentally 23% power transfer has been observed limited by the absorption and gain in our Barium Titanate crystal. We have also studied seeding the semilinear mirror with a separate beam as a means of starting its oscillation in conditions where high power transfer efficiency is required and investigated regions of bistability in the output which also occur in this regime.


2013 ◽  
Vol 800 ◽  
pp. 201-204
Author(s):  
Wang Hong ◽  
Ling Yun Wang ◽  
Ri Sheng Li

Porosity is formed because of the keyhole collapse. The porosity formation is associated with the melt pool dynamics, the keyhole collapse and solidification processes. The objective of the paper is t to investigate porosity formation mechanisms and fluid flow in the melt pool using the volume of fluid method. The results indicate that the formation of porosity in continuous wave keyhole mode laser welding is associated to keyhole collapse, backfilling of liquid metal close the gas exit of the laser welding keyhole, surface tension of the gas/liquid interface play an important role in the backfilling downward to the keyhole right after laser beams left.Keywords: porosity; keyhole; collapse; welding; model


1981 ◽  
Vol 38 (4) ◽  
pp. 309-313 ◽  
Author(s):  
V.M. Baev ◽  
G. Gaida ◽  
H. Schröder ◽  
P.E. Toschek

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