调控抽运脉冲的时、空啁啾改善太赫兹波输出效率

Improving Output Efficiency of Terahertz Wave by Controlling Temporal and Spatial Chirps of Pump Pulses

从理论和实验两方面研究了调控抽运脉冲的时、空啁啾特性对于波面倾斜法产生太赫兹波输出效率的影响。实验和数值模拟证明:对于附加时间啁啾情况,当附加正时间啁啾时,太赫兹波输出效率与附加啁啾量呈非线性关系,并具有最佳值;当附加负时间啁啾时,太赫兹输出效率与附加啁啾量呈线性反比关系。对于附加空间啁啾情况,不论附加空间啁啾的大小和符号如何,都会降低太赫兹波的输出效率,并且随着空间啁啾量的增加而快速下降。这些结果对基于波面倾斜法产生超快太赫兹波系统的优化和调控具有指导意义。

The output efficiency of terahertz wave based on the tilted-pulse-front geometry by controlling temporal and spatial chirps of pump pulses is improved theoretically and experimentally. For the situation of the additional temporal chirp, the results show that the output efficiency of terahertz wave is nonlinear to the additional positive chirp of pump pulses and there is an optimum selection. However, it is linearly inversely proportional to the additional negative chirp of pump pluses. For the situation of the additional spatial chirp, the results show that the output efficiency of terahertz wave is always decreased, regardless of the size and sign of the additional chirp. Furthermore, the dramatic decrease of the output efficiency appears with the increase of the spatial chirp. These results have a guiding significance for the optimization and regulation of the ultrafast terahertz wave system based on the tilted-pulse-front method.