Terahertz Radiation Generation by Frequency Mixing of Hermite–Cosh–Gaussian Laser Beams in Density-Modulated Cold Magnetized Plasma

We report a theoretical investigation for extremely bright terahertz (THz) radiation generation by mixing of dichromatic Hermite–Cosh–Gaussian (HChG) laser beams in periodically rippled density plasma in the presence of external dc magnetic field. The magnetic field is applied perpendicular to the direction of propagation and to the polarization states of laser beams. THz field amplitude significantly increases with applied dc magnetic field. Our investigations reveal that frequency resonance shifts with the applied magnetic field. As a result, THz frequency tuning is possible with applied magnetic field. The electron neutral collisions have no effect on resonance condition but THz amplitude and efficiency decreases with increase in frequency of electron neutral collisions. We find that THz field profile strongly depends on laser parameters like Cosh decentred parameter $b$ and order of Hermite function $s$ , and independent of applied magnetic field. Our theoretical investigations predict that GV/m THz field with efficiency ~7% for laser field ~50 GV/m and 80-kG applied dc magnetic field can be obtained for optimized set of laser and plasma parameters.