Self-focusing of dark hollow Gaussian laser beam and its effect on second harmonic generation in collisionless plasma: Moment theory approach

2019 ◽  
Author(s):  
Jyoti Wadhwa ◽  
Deepanshu Yadav ◽  
Arvinder Singh
Keyword(s):  
Second Harmonic Generation ◽  
Laser Beam ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Collisionless Plasma ◽  
Theory Approach ◽  
Gaussian Laser Beam ◽  
Moment Theory ◽  
Self Focusing

scholarly journals Second harmonic generation of q-Gaussian laser beam in plasma channel created by ignitor heater technique

2019 ◽  
Vol 37 (2) ◽  
pp. 184-196 ◽  
Author(s):  
Naveen Gupta
Keyword(s):  
Second Harmonic Generation ◽  
Laser Beam ◽  
Harmonic Generation ◽  
Plasma Channel ◽  
Second Harmonic ◽  
Laser Beams ◽  
Theory Approach ◽  
Gaussian Laser Beam ◽  
Incident Laser ◽  
Pump Frequency

AbstractThis paper presents a scheme for second harmonic generation (SHG) of q-Gaussian laser beam in plasma channel created by ignitor heater technique. The ignitor beam creates plasma by tunnel ionization of air. The heater beam heats the plasma electrons and establishes a parabolic density profile. The third beam (q-Gaussian beam) is guided in this plasma channel under the combined effects of density nonuniformity of the plasma channel and relativistic mass nonlinearity of the plasma electrons. The propagation of q-Gaussian laser beam through the plasma channel excites an electron plasma wave at pump frequency that interacts with the incident laser beam to produce its second harmonics. The formulation is based on finding the numerical solution of the nonlinear Schrodinger wave equation for the fields of the incident laser beams with the help of moment theory approach. Particular emphasis is put on dynamical variations of the spot size of the laser beams and conversion efficiency of the second harmonics with distance of propagation.

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.

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