Terahertz Field Generation by Beating of Mixed Profile Lasers in Under-Dense Plasma

Mechanism of laser beat wave mixing is revisited with an approach of usage of mixed profile lasers namely cosh-Gaussian (CHG) and dark hollow Gaussian (DHG) lasers altogether in under-dense ripple density plasma. Under-dense plasma is more realistic laboratory plasma which is weakly ionized and exhibit electron neutral collision to good extent. Plasma density ripple helps to achieve tunable resonance by matching of beat wavenumber with ripple wavenumber for maximum energy transfer to ensure maximized yield of emitted terahertz (THz) radiation. It is reported that the combination of mixed laser helps achieving larger amplitude THz radiation with greater efficiency as compared to the mixing of two Gaussian lasers. Besides, bifocal THz radiations with varied peak intensities are observed with mixing of CHG and DHG laser, those have extensive utility in medical applications for diagnostics and treatment procedures in cancer disease.