Terahertz Generation via Two-Color Laser Pulses

This paper is a review on Terahertz generation, based on a method called “Two-Color Laser Pulses”, in which terahertz pulse is generated by focusing a pulse and its second harmonic into gas target at the same time, in the output. Terahertz generation set up, physical processes involved in terahertz generation in this method and the most acceptable reason for the amplification of terahertz pulse in this process is discussed. Also, the role of phase difference between the laser pulse and its second harmonic for generated pulse is reviewed. At last, generated THz amplitude based on different phases between the two amplitudes is surveyed. Nonlinear crystal is used in this generation method and the method of generation is a nonlinear process. Therefore, the role of nonlinear crystal in the process of Terahertz pulse generation, its position in optical set-up and the advantage of using it, are pointed out.