Terahertz radiation generation by lasers with remarkable efficiency in electron–positron plasma

• First proposal of photo-mixing of spatial-super-Gaussian (SSG) lasers in electron–positron (e–p) plasma.
• Large amplitude nonlinear current due to the contribution of both the plasma species.
• Magnetic field as an additional parameter for tunable THz radiation with a remarkable efficiency of ∼6%.

Photo-mixing of spatial-super-Gaussian lasers and electron–positron plasma are proposed for realizing a large amplitude nonlinear current in order to generate an efficient terahertz radiation. An external magnetic field together with a proper index of the lasers helps achieving controllable current and hence, the focused radiation of tunable frequency and power along with a remarkable efficiency of the scheme as ∼6%.