Abstract-Excitation of terahertz radiation by parametric coupling of a laser beam and its frequency shifted second harmonic in a corrugated magnetized plasma

Kusum Lata Mann, Vivek Sajal, Anuraj Panwar, Navneet K.Sharma,



https://www.sciencedirect.com/science/article/pii/S0030402618317339

An analytical scheme is developed for the excitation of terahertz radiation (THz) by parametric coupling of a linearly polarized fundamental laser beam (ω1,k→1) and its frequency shifted second harmonic laser (ω2,k→2) in corrugated magnetized plasma. The laser exerts nonlinear ponderomotive force on plasma electrons at frequencies 2ω1 and ω1−ω2 consequently density perturbations at these frequencies arise. These density perturbations couple with plasma corrugations of suitable wave number q and produces density oscillations at (2ω1,2k1−qz) and (ω1−ω2,k1−k2−qz). Density oscillations beat with oscillatory velocities of electrons at ω1 and ω2 (due to lasers) and resonantly excite terahertz radiation at phase matching conditions of frequency ω=2ω1−ω2 and wave number k=2k1−k2−q. Perturbation technique is used to obtain the electric field of terahertz radiation. The terahertz electric field amplitude 8.04×106V/m is achieved for the lasers intensity of ∼ 1015 W/cm2 in a 10% corrugated under dense plasma at applied magnetic field∼175 kG.