Research On The Effect Of Chirp Characteristics Influence The Tilted-pulse-front Generation Terahertz

Terahertz?THz?technology is widely used in many areas for lots of excellent properties in varies areas,such as astronomy,communications,biology and security screening.Therefore,more and more scholars have been paid attention to it.However,industrial application of THz radiation is still few due to the low output power of THz sources.For current research work,it is important to develop a method to generate THz radiation with high pulse energy high repetition rate and high energy conversion efficiency.In this paper,the effect on THz radiation in LiNbO₃ by the optical rectification effect tilted-pulse-front pumping was analyzed experimentally and theoretically.The thesis was consist of the following chapters:1?The current status of THz science and technology is reviewed.In addition,the generation method and detection technology of THz wave are introduced.2?The basic principle of femtosecond laser pulse pumped nonlinear crystal generating THz radiation based on the optical rectification effect was introduced.The wave equation is derived under ideal conditions,and the efficiency formula of crystal radiation THz is analyzed in detail.Based on this theory,the key factors that affected the efficiency of THz wave are analyzed.3?Based on the optical rectification effect and the theoretical basis of the tilted wave-front,a dynamic theoretical model of nonlinear crystal radiation THz wave is established.According to the model,the influence of the chirp of the pump pulse on the THz radiation is analyzed at the same time.4?By using the photonic crystal fiber mode-locking femtosecond laser amplifier and the theoretical model combined with the numerical simulation results,the experiment of dynamic process of THz wave generated by the additional temporal and spatial chirp of the pump pulse is carried out.The results are in complete agreement with the numerical simulation results.