Amplitude and polarization effects in self-focusing of laser radiation in media with spatial dispersion of nonlinearity

1988 ◽  
Vol 31 (9) ◽  
pp. 737-745 ◽  
Author(s):  
A. A. Golubkov ◽  
V. A. Makarov
Keyword(s):  
Laser Radiation ◽  
Spatial Dispersion ◽  
Polarization Effects ◽  
Self Focusing

Effect of spatial dispersion of nonlinearity on self-focusing of laser radiation in liquid crystals: Theory and numerical experiments

1979 ◽  
Vol 22 (1) ◽  
pp. 36-41 ◽  
Author(s):  
S. M. Arakelyan ◽  
G. A. Vardanyan ◽  
V. A. Vysloukh ◽  
G. A. Lyakhov ◽  
V. A. Makarov ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Liquid Crystals ◽  
Numerical Experiments ◽  
Spatial Dispersion ◽  
Self Focusing

Self-focusing threshold of a beam of laser radiation in rubidium vapor

2016 ◽  
Vol 83 (11) ◽  
pp. 667 ◽  
Author(s):  
V. A. Sautenkov ◽  
M. N. Shneĭder ◽  
S. A. Saakyan ◽  
E. V. Vil’shanskaya ◽  
D. A. Murashkin ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Rubidium Vapor ◽  
Self Focusing

scholarly journals Relativistic self-focusing of transmitted laser radiation in plasmas

2000 ◽  
Vol 18 (1) ◽  
pp. 101-107 ◽  
Author(s):  
MEENU V. ASTHANA ◽  
DINESH VARSHNEY ◽  
M.S. SODHA
Keyword(s):  
Dielectric Constant ◽  
Laser Radiation ◽  
Critical Power ◽  
Interaction Process ◽  
Gaussian Laser Beam ◽  
Laser Plasma Interaction ◽  
Paraxial Ray Approximation ◽  
Self Focusing ◽  
Beam Incident ◽  
Paraxial Ray

This paper presents an analysis of relativistic self-focusing of a Gaussian laser beam incident normally on a plane interface of a linear medium and a nonlinear, nonabsorbing plasma with an intensity dependent dielectric constant. Considering the nonlinearity to arise from the relativistic variation of mass and the Lorentz force on electrons. Following Wentzel–Kramers–Brillouin (WKB) and paraxial ray approximation the phenomenon of relativistic self-focusing of the transmitted laser radiation has been analyzed for the arbitrary magnitude of nonlinearity. Change in the intensity distribution along the wavefront of the Gaussian beam, due to refraction at the interface has also been taken into account. The variation of beamwidth parameter with distance of propagation, self trapping condition and critical power has been evaluated. Numerical estimates for typical parameters of laser plasma interaction process indicate the refraction at the interface to have a significant effect on self-focusing.

scholarly journals Role of Dislocations in the Process of Degradation of Semiconductor Lasers with Electronic Energy Pumping. Experimental Research

2020 ◽  
Vol 19 (6) ◽  
pp. 507-511
Author(s):  
A. S. Garkavenko ◽  
V. A. Mokritsky ◽  
O. V. Maslov ◽  
A. V. Sokolov
Keyword(s):  
Refractive Index ◽  
Laser Radiation ◽  
Semiconductor Lasers ◽  
Electronic Energy ◽  
The Self ◽  
Generation Threshold ◽  
Degradation Processes ◽  
Energy Pumping ◽  
Self Focusing ◽  
Non Equilibrium

Light self-destruction-degradation of the second type has been observed in samples of semiconductor lasers with electronic  energy  pumping with high  optical  homogeneity and good quality of surface treatment.  In these  samples,  damage appeared in the form of cords perpendicular to the ends of the resonator. According to the current understanding of the passage of powerful light streams through various media, the emergence of narrow light channels is due to the phenomenon of self-focusing. It refers to the fundamental physical mechanisms of propagation of laser radiation and is caused by nonlinear phenomena arising in a medium under the influence of high-power laser radiation. The physical reason for self-focusing is an increase in the refractive index n in a strong light field. Thermal self-focusing is the most probable cause of radiation redistribution in the active region of the crystal. However, it is possible that in the initial stage of the appearance of light channels a certain role is played by the growth of the intensity of radiation in certain sections of the crystal because of the instability of generation or small fluctuations in the pump current density. Then the process acquires an avalanche character, since the localization of the ray in the channel increases the density of light radiation which can lead to overheating of the substance and the activation of the thermal self-focusing mechanism. The experiments performed in this paper have shown that optically homogeneous crystals possess maximum resistance to degradation processes. In them,  the critical power of light destruction is determined by the self-focusing threshold of radiation in a material. Since the nonlinear addition to the refractive index Δn = n2E2 at the self-focusing threshold is determined by the change in the concentration of non-equilibrium carriers ΔN(E2), the value of the maximum fluctuation DΔNmax itself is proportional to the value of the non-equilibrium carrier concentration at the generation threshold ΔNpores and the relative excess of the generation threshold J = (j – jn)/jn. Thus, a low threshold concentration of non-equilibrium carriers is one of the conditions for increasing material resistance to degradation processes. In doped crystals ΔNpores is less than in  pure materials. This, perhaps, explains the rather higher value of Pcritial  in the optimally doped homogeneous n-GaAs. Smaller values of Pcritial in p-type samples doped with zinc can be associated not only with the inhomogeneity of these crystals, but also with large generation thresholds. In addition, the cross section for absorption of radiation by holes is about 3–4 times larger than by electrons, which can also reduce the self-destruction threshold of lasers. At Т = 300 K, the lasing thresholds are higher that naturally reduces the value of the self-focusing threshold.

Self-focusing of laser radiation in the case of a Fredericks transition

1982 ◽  
Vol 138 (10) ◽  
pp. 324 ◽  
Author(s):  
V.F. Kitaeva ◽  
A.S. Zolot'ko ◽  
N.N. Sobolev
Keyword(s):  
Laser Radiation ◽  
Self Focusing

scholarly journals Can Self-focusing of Intense Laser Beams Cause Bose -Einstein Condensation in to a Superfluid State ?

1989 ◽  
Vol 44 (3) ◽  
pp. 243-244 ◽  
Author(s):  
F. Winterberg
Keyword(s):  
Refractive Index ◽  
Laser Radiation ◽  
Intense Laser ◽  
Laser Beams ◽  
Einstein Condensation ◽  
Superfluid State ◽  
Bose Einstein Condensation ◽  
Self Focusing ◽  
Intense Laser Radiation ◽  
Bose Einstein

Abstract The cause of the phenomenon of self-focusing of intense laser radiation in solids is the nonlinear inten­ sity dependent refractive index [1] n = nl + n 2E2, (1)

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