Development of high power THz source using phase control technique

我们已经证明，相位控制的太赫兹辐射可以产生由激光产生的电离前沿，这是诱导光场诱导电离（OFI）在空气中与脉冲电场产生的突发电流。辐射光谱的峰值频率取决于OFI的上升时间。在30和100 fs（FWHM）的脉冲持续时间的辐射的中心频率被观察到分别为0.3和0.1太赫兹。我们还演示了利用超短激光脉冲产生的等离子体与太赫兹波相互作用的闪光电离方案的原理验证实验。当等离子体在电磁波周围瞬间产生时，波的频率上转换为取决于等离子体频率的频率。我们观察到的频率上转换从0.35太赫兹到3太赫兹的激光辐照的ZnSe晶体。

We have demonstrated that the phase-controlled terahertz radiation can be generate by the burst current produced by a laser created ionization front, which is induced an optical-field-induced ionization (OFI) in air with a pulsed electric field. The peak frequency of the radiation spectrum depends on the rise time of the OFI. The central frequencies of the radiation were observed to be 0.3 and 0.1 THz at the pulse durations of 30 and 100 fs (FWHM), respectively. We also have demonstrated the proof-of-principle experiment of flash ionization scheme using the interaction between a terahertz wave and plasmas created by an ultrashort laser pulse. When plasmas were instantaneously created around an electromagnetic wave, frequency of the wave up-converted to the frequency, which depended on the plasma frequency. We observed frequency up-conversion from 0.35 THz to 3 THz by the irradiance of the laser in ZnSe crystal.