Terahertz radiation generation by beating of two spatial-Gaussian lasers in the presence of a static magnetic field

Abstract

Resonant excitation of terahertz (THz) radiation based on beating of two spatial-Gaussian lasers having different frequencies and wave numbers but the same electric field amplitudes is proposed in a spatially periodic density plasma in the presence of a static magnetic field applied perpendicular to the direction of propagation of the lasers. In this process, the ponderomotive force is developed with its components parallel and perpendicular to the direction of propagation of the lasers. This leads to a nonlinear oscillatory current that resonantly excites the THz radiation with the frequency of the order of the upper hybrid frequency. The contribution of magnetic field, laser beamwidth, and amplitude and periodicity of the density ripples is discussed for the efficient THz radiation generation. With the optimization of these parameters, the efficiency on the order of 10(-3) or larger can be achieved in the present scheme.

Multifocal terahertz radiation by intense lasers in rippled plasma

“…Here, we clearly observe that the lasers with lower beam width produce intense radiation and the same is the case with higher index lasers (p). These results are in agreement with the observations made by other researchers [24][25][26].…”

Effects of the evolution of two cross‐focused Gaussian laser beams on the terahertz generation in thermal collisional plasma

“…Coherent sub-THz radiation as a result of femtosecond infrared filaments in air was detected experimentally by Tzortzakis et al [9] An efficient THz emission was recorded by optimizing the specifications of pump pulses by Wang et al [15] Their group measured a quite high-energy pulse, 0.57 J, for 5.5 THz radiation and also proposed a new design to improve conversion energy. [24] Moreover, the effects of two Gaussian spatial profile laser beams on the amplitude of THz radiation in a collisional plasma and in the presence of external electric field were investigated by Sharma et al [25] Singh et al [26] found that electron neutral collision frequency acts as a resistive factor and leads to reduce the output of THz radiation amplitude. They examined optimum conditions for efficient THz emission by tuning the different parameters of laser and plasma and found that when the beating frequency reaches p , THz generation efficiency approaches its maximum intensity.…”

“…The efficiency of this scheme can be reached ∼10 −3 by optimizing the laser and plasma parameters. [24] Moreover, the effects of two Gaussian spatial profile laser beams on the amplitude of THz radiation in a collisional plasma and in the presence of external electric field were investigated by Sharma et al [25] Singh et al [26] found that electron neutral collision frequency acts as a resistive factor and leads to reduce the output of THz radiation amplitude. Whereas this can be compensated by employing an special super Gaussian laser profile and in the presence of external magnetic field of strength 1-5 T. They achieve 6% efficiency for THz generation applying this mechanism under optimum conditions.…”

Terahertz radiation emission using plasma‐filled dielectric liner with the effects of pre‐modulated relativistic electron beam

“…Malik et al [14] proposed that the power and frequency of THz radiation excited resonantly by the mixing of two Gaussian laser pulses in a periodic density rippled plasma in the presence of external magnetic field can be tuned by the magnetic field, periodicity and amplitude of the density ripples.…”