利用飞秒激光脉冲整形进行太赫兹波整形

THz Wave Shaping Technology via the Femtosecond Laser Pulse Shaping

产生太赫兹的一般方法是用超短激光脉冲照射光导天线或半导体材料,产生的太赫兹脉冲形状一般比较复杂。如果要将太赫兹辐射应用于通讯,或者分子反应动力学过程的相关控制,需要能够产生任意形状的太赫兹脉冲。介绍了利用激光脉冲整形对太赫兹波整形的原理和实验研究进展,通过对激发太赫兹辐射的飞秒激光脉冲整形,可以实现对太赫兹波形的控制。控制激励脉冲序列的脉冲间隔可以改变太赫兹脉冲系列的相位关系,调制激光脉冲强度可以产生相应的二进制太赫兹脉冲编码,用周期可变的相位掩模板对飞秒激光脉冲整形实现可调谐窄带太赫兹辐射。

The THz radiation is usually generated by means of illuminating a PC antenna or semiconductor material with ultra short laser pulses. This short pulse usually produces a complex THz waveform. To extend the flexibility of THz radiation for some applications, such as coherent control of molecular states or communications, it is desirable to have capabilities of generating arbitrarily shaped THz waves. We introduce the principle of THz wave shaping and research development here. Tbe waveform control of THz radiation can be fulfilled via the femtosecond laser pulse shaping. The relation of phases between theTHz pulse sequence can be changed simply by modifying the pulse intervals which control the pulse sequence. The amplitude modulation of the laser pulses can generate THz binary bits. Tunable narrow-band THz radiation can be generated by femtosecond pulse shaping via periodically tunable phase mask.