Generation of THz pulse in air plasma controlled by external electric field

In the past few years, new applications of terahertz wave have given rise to the development of intense terahertz wave source and modulation of terahertz wave. However, rigorous experimental conditions or few theoretical explanations were in these works. In this paper, a method to enhance and control the THz pulse generation in air plasma by external electric field is proposed. Two theoretical models, the optics Four-wave-mix-frequency and the electrodynamics electromagnetic radiation are given to explain the results of the proposed method respectively.