Intense diffraction of a laser beam due to self‐focusing in underdense plasma

1985 ◽  
Vol 58 (8) ◽  
pp. 2916-2921 ◽  
Author(s):  
D. Giulietti ◽  
A. Giulietti ◽  
M. Lucchesi ◽  
M. Vaselli
Keyword(s):  
Laser Beam ◽  
Self Focusing ◽  
Underdense Plasma

scholarly journals Laser beam self-focusing in an nc/100 plasma with 20 ns and 3 ns pulses

1986 ◽  
Vol 4 (3-4) ◽  
pp. 435-438
Author(s):  
A. Giulietti ◽  
D. Giulietti ◽  
M. Lucchesi ◽  
M. Vaselli
Keyword(s):  
Laser Beam ◽  
Optical Breakdown ◽  
Self Focusing ◽  
Underdense Plasma

The interaction of a laser beam (1·06 μm) with an underdense plasma produced by optical breakdown of helium was experimentally studied. Evidence for whole beam self-focusing is reported and discussed.

scholarly journals Second-harmonic generation by relativistic self-focusing of cosh-Gaussian laser beam in underdense plasma

2015 ◽  
Vol 34 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Arvinder Singh ◽  
Naveen Gupta
Keyword(s):  
Differential Equation ◽  
Second Harmonic Generation ◽  
Laser Beam ◽  
Plasma Wave ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Spot Size ◽  
Gaussian Laser Beam ◽  
Self Focusing ◽  
Underdense Plasma

AbstractThis paper presents theoretical investigation of effect of relativistic self-focusing of cosh-Gaussian (ChG) laser beam on second-harmonic generation in an underdense plasma. Steep transverse density gradients are produced in the plasma by the electron plasma wave excited by relativistic self-focusing of ChG laser beam. The generated plasma wave interacts with the pump beam to produce its second harmonics. Following Jeffrey Wentzel Kramers Brillouin (J.W.K.B) approximation and moment theory the differential equation governing the evolution of spot size of laser beam with distance of propagation has been derived. The differential equation so obtained has been solved numerically by the Runge–Kutta method to investigate the effect of decentered parameter, intensity of laser beam as well as density of plasma on self-focusing of the ChG laser beam, and generation of its second harmonics. It has been observed that the peak intensity of the laser beam shifts in the transverse direction by changing the decentered parameter and a noticeable change is observed on focusing of the laser beam as well as on conversion efficiency of second harmonics.

scholarly journals Second harmonic generation in underdense plasma

1988 ◽  
Vol 6 (2) ◽  
pp. 141-147 ◽  
Author(s):  
D. Giulietti ◽  
G. P. Banfi ◽  
I. Deha ◽  
A. Giulietti ◽  
M. Lucchesi ◽  
...  
Keyword(s):  
Experimental Data ◽  
Second Harmonic Generation ◽  
Laser Beam ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Experimental Conditions ◽  
Emission Pattern ◽  
Peak Intensity ◽  
Self Focusing ◽  
Underdense Plasma

Experimental data are reported on second harmonic generation (SHG) during the interaction between a Nd laser beam (20 ns pulse-duration and peak intensity 1013 W/cm2) and a plasma of density 1019 cm−3 produced in helium. The behavior of self-focusing and the onset of steep plasma gradients under the same experimental conditions have been previously characterized by independent techniques as already reported. In the light of these former findings, the observed SH magnitude, emission pattern and time dependence are briefly discussed and compared with expectations.

Self-focusing of cosh-Gaussian laser beam in collisional plasma: effect of nonlinear absorption

2021 ◽  
Author(s):  
Naveen Gupta ◽  
Sandeep Kumar ◽  
A Gnaneshwaran ◽  
Sanjeev Kumar ◽  
Suman Choudhry
Keyword(s):  
Laser Beam ◽  
Nonlinear Absorption ◽  
Collisional Plasma ◽  
Gaussian Laser Beam ◽  
Self Focusing ◽  
Plasma Effect

Relativistic self-focusing of a rippled laser beam in a plasma

1999 ◽  
Vol 62 (4) ◽  
pp. 389-396 ◽  
Author(s):  
M. V. ASTHANA ◽  
A. GIULIETTI ◽  
DINESH VARSHNEY ◽  
M. S. SODHA
Keyword(s):  
Refractive Index ◽  
Laser Beam ◽  
The Self ◽  
Laser Beams ◽  
Radial Dependence ◽  
Main Beam ◽  
Gaussian Laser Beam ◽  
Self Focusing ◽  
Saturation Effects ◽  
Paraxial Ray

This paper presents an analysis of the relativistic self-focusing of a rippled Gaussian laser beam in a plasma. Considering the nonlinearity as arising owing to relativistic variation of mass, and following the WKB and paraxial-ray approximations, the phenomenon of self-focusing of rippled laser beams is studied for arbitrary magnitude of nonlinearity. Pandey et al. [Phys. Fluids82, 1221 (1990)] have shown that a small ripple on the axis of the main beam grows very rapidly with distance of propagation as compared with the self-focusing of the main beam. Based on this analogy, we have analysed relativistic self-focusing of rippled beams in plasmas. The relativistic intensities with saturation effects of nonlinearity allow the nonlinear refractive index in the paraxial regime to have a slower radial dependence, and thus the ripple extracts relatively less energy from its neighbourhood.

scholarly journals Relativistic self-focusing in underdense plasma

2001 ◽  
Vol 152-153 ◽  
pp. 705-713 ◽  
Author(s):  
M.D Feit ◽  
A.M Komashko ◽  
A.M Rubenchik
Keyword(s):  
Self Focusing ◽  
Underdense Plasma
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