Second Harmonic Generation of Self-Focused Cosh-Gaussian Laser Beam in Thermal Quantum Plasma by Excitation of an Electron Plasma Wave

2016 ◽  
Vol 56 (9) ◽  
pp. 889-904 ◽  
Author(s):  
N. Gupta ◽  
A. Singh
Keyword(s):  
Second Harmonic Generation ◽  
Laser Beam ◽  
Plasma Wave ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Electron Plasma ◽  
Quantum Plasma ◽  
Gaussian Laser Beam ◽  
Electron Plasma Wave

Study of optical guiding of the Hermite–Gaussian laser beam in preformed collisional parabolic plasma channel and second harmonic generation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jyoti Wadhwa ◽  
Arvinder Singh
Keyword(s):  
Second Harmonic Generation ◽  
Laser Beam ◽  
Plasma Wave ◽  
Harmonic Generation ◽  
Plasma Channel ◽  
Second Harmonic ◽  
Incident Beam ◽  
Electron Plasma ◽  
Gaussian Laser Beam ◽  
Electron Plasma Wave

Abstract In the present work, the scheme of optical guiding of the Hermite–Gaussian laser beam and the generation of second-harmonic 2ω radiation (ω being the frequency of incident beam) is presented in plasma having the preformed collisional plasma channel in which density variation is parabolic. The nonlinear coupling of excited electron plasma wave with the carrier or incident beam results in the production of second harmonics of the latter. The method of moments is used for finding the coupled differential equations for the beam diameter to study the dynamics of the Hermite–Gaussian laser beam in plasma under the effect of the collisional parabolic channel. For numerical simulations, the Runge–Kutta fourth-order numerical method is used. Standard perturbation theory gives the equation for excitation of electron plasma wave which further acts as the source term for the second harmonic generation. The numerical results show that the preformed plasma channel has a significant effect on the guiding as well as on the 2ω generation of the Hermite–Gaussian laser beam in plasma.

Optical Guiding of Intense Hermite-Gaussian Laser Beam in Preformed Plasma Channel and Second Harmonic Generation

2021 ◽  
Author(s):  
Jyoti Wadhwa ◽  
Arvinder Singh
Keyword(s):  
Differential Equations ◽  
Second Harmonic Generation ◽  
Laser Beam ◽  
Harmonic Generation ◽  
Plasma Channel ◽  
Second Harmonic ◽  
Electron Plasma ◽  
Gaussian Laser Beam ◽  
Electron Plasma Wave ◽  
Preformed Plasma

Abstract This work presents the scheme of optical channeling of the intense Hermite Gaussian laser beam and second-harmonic generation in plasma having the preformed plasma channel, where relativistic nonlinearity is operative. Excitation of the electron plasma wave at the incident beam frequency leads its coupling with the latter produces the second harmonics of the beam. For the formulation of differential equations for the beam waists of the Hermite Gaussian laser beam propagating through the channel, the method of moments has been used. The solutions of the coupled differential equations are found using Runge Kutta fourth-order numerical method. Perturbation theory has been applied to find the equation governing the excitation of electron plasma wave and hence the source term for the second-harmonic yield. It has been observed that the preformed plasma channel helps to optically guide the laser beam and enhances the efficiency of second-harmonic generation of various modes of the Hermite Gaussian laser beam in plasma.

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 Effect of self-focused cosh Gaussian laser beam on the excitation of electron plasma wave and particle acceleration

2016 ◽  
Vol 34 (4) ◽  
pp. 621-630 ◽  
Author(s):  
B. Gaur ◽  
P. Rawat ◽  
G. Purohit
Keyword(s):  
Particle Acceleration ◽  
Laser Beam ◽  
Plasma Wave ◽  
Electron Plasma ◽  
The Self ◽  
Acceleration Process ◽  
Gaussian Laser Beam ◽  
Electron Plasma Wave ◽  
Self Focusing ◽  
Paraxial Ray

AbstractThis work presents an investigation of the self-focusing of a high-power laser beam having cosh Gaussian intensity profile in a collissionless plasma under weak relativistic-ponderomotove (RP) and only relativistic regimes and its effect on the excitation of electron plasma wave (EPW), and particle acceleration process. Nonlinear differential equations have been set up for the beam width and intensity of cosh Gaussian laser beam (CGLB) and EPW using the Wentzel-Kramers-Brillouin and paraxial-ray approximations as well as fluid equations. The numerical results are presented for different values of decentered parameter ‘b’ and intensity parameter ‘a’ of CGLB. Strong self-focusing is observed in RP regime as compared with only relativistic nonlinearity. Numerical analysis shows that these parameters play crucial role on the self-focusing of the CGLB and the excitation of EPW. It is also found that the intensity/amplitude of EPW increases with b and a. Further, nonlinear coupling between the CGLB and EPW leads to the acceleration of electrons. The intensity of EPW and energy gain by electrons is significantly affected by including the ponderomotive nonlinearity. The energy of the accelerated electrons is increased by increasing the value of ‘b’. The results are presented for typical laser and plasma parameters.

Sign in / Sign up

Export Citation Format

Share Document