We report terahertz (THz) wave generation based on mixing of two radially polarized hollow Gaussian laser beams in periodic density plasma. We incorporate the effect of plasma electron temperature on THz intensity and efficiency. Our investigations reveal that emitted THz is radially polarized. Brightness and efficiency of THz significantly increase with plasma electron temperature. Our scheme predicts upto 2.4-fold enhancement in THz conversion efficiency with increase in plasma electron temperature from 0–10 KeV. We observe that effect of plasma electron temperature is more prominent when difference of laser frequency matches with plasma frequency i.e. The profile of THz depends on the laser parameters and it is independent of plasma electron temperature. A high THz field (∼10 MV cm−1) and high conversion efficiency (∼6%) is predicted for optimized pump laser and plasma parameters.

We report a theoretical model of radially polarized terahertz (THz) wave emission by nonlinear mixing of bicolor, radially polarized lasers having a top-hat envelope profile [s (profile index)≥1] in density modulated hot plasma. We investigate the effect of the laser profile index on the emitted THz field profile and found that THz field amplitude and peak location changes with the laser profile index. Our numerical investigations show that THz field amplitude is the highest around ωp≈ω1−ω2 (where ωp is the plasma frequency and ω1 and  ω2 are the laser frequencies). We observe that phase matching can be achieved with the help of the plasma density modulation wave number. The plasma density modulation wave number increases with electron temperature and decreases with the frequency mismatch between ωp and ω1−ω2. We found that the conversion efficiency is maximum at ω1−ω2≈ωp and increases fivefold with an increase in electron thermal velocity (vth) from vth=0 to vth=0.2c, where c is the speed of light.

An analytical model for forward emission of radially polarized terahertz (THz) wave emission by photo mixing of two-color, radially polarized lasers having hollow sinh super-Gaussian envelopes in hot plasma with periodic density is developed. THz field distribution is optimized with the help of laser envelope parameters. Numerical investigations show that THz field amplitude is maximum at ω1 − ω2 ≈ ωp (resonant excitation). Our investigations show that THz field amplitude increases with electron temperature without affecting resonance condition. The position of THz field peaks shifts with laser parameters (i.e., orders of hollow sinh and super-Gaussian, respectively) but not with electron temperature. It is also found that THz conversion efficiency increases manifold with the increase in electron temperature.

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