Effects of transverse static electric field on terahertz radiation generation by beating of two transversely modulated Gaussian laser beams in a plasma

Abstract

Resonant excitation of terahertz (THz) radiation by nonlinear coupling of two filamented spatial-Gaussian laser beams of different frequencies and wave numbers is studied in plasma having transverse static electric field. The static ponderomotive force due to filamented lasers is balanced by the pressure gradient force which gives rise to transverse density ripple, while, the nonlinear ponderomotive force at frequency difference of beating lasers couples with density ripple giving rise to stronger transverse nonlinear current which results into the excitation of THz radiation at resonance. The coupling is further enhanced by the presence of static electric field and spatial-Gaussian nature of laser beams. An increase of six-fold in the normalized amplitude of THz is observed by applying a direct current field of about 50 KV. Effects of frequency, laser beam width, and periodicity factor of modulated laser amplitude are studied for the efficient THz radiation generation. These results can be utilized for generating controlled tunable THz sources for medical applications using low filament intensities (~ 1014 W/cm2) of beating lasers.

Studies of Terahertz Sources and Their Applications

“…Malik and Malik [69][70][71][72] investigated the role of an external DC magnetic field in tuning the frequency and power of terahertz radiation. Varshney et al [73,74] proposed a scheme for the generation of THz radiation from rippled density magnetized plasma by beating of extraordinary mode lasers.…”

“…Malik and Singh [74] used two super-Gaussian lasers to generate the highly focused terahertz radiation by frequency mixing. Chaudhary et al [75] used Hermite cosh Gaussian lasers to generate the efficient intensity distribution of tunable terahertz radiation.…”

Enhancement of Magnetic Vortex Acceleration by Laser Interaction with Near-Critical Density Plasma inside a Hollow Conical Target

“…Ion acceleration driven by ultraintense laser pulse has huge potential advantages and a wide promising application prospect [1][2][3], such as proton imaging [4], hadron therapy [5], tabletop particle accelerator [6], and fast ignition of inertial confinement fusion [7,8]. In recent years, the laserdriven high-energy ion acceleration has made much progress, and a number of researchers have explored key physical issues and techniques for obtaining high-energy ions [9][10][11].…”

Terahertz Radiation from a Plasma Cylinder with External Radial Electric and Axial Magnetic Fields

“…Frequency up-or downconversion of electromagnetic radiation can be realized through nonlinear wavematter and wave-wave interaction. THz radiation can also be produced in intense laser interaction with matter [3,5,[6][7][8][9][10][11][12][13][14]. T-rays can also be produced by the oscillating electrons in laser-induced wakefields [15][16][17], Smith-Purcell effect of the electron beams in laser-matter interactions [18], two-color laser gas-plasma interaction [19,20], transition-Cherenkov effect from laser filaments [21], laser-driven wire-guided helical undulators [22], and linear and nonlinear mode conversion [23], as well as laser interaction with strongly magnetized plasmas [24][25][26][27].…”