We demonstrate the generation of intense, sub-cycle terahertz (THz) pulses with variable elliptical polarization and peak fields above 80 kV/cm from large aperture photoconductive antennas using a specific interdigitated structure. The latter is composed of horizontal and vertical electrodes, which allow the generation of two quasi-half-cycle THz pulses with orthogonal polarization. A time delay between the two THz pulses is introduced by a phase delay mask covering only the parts of the antenna with horizontal electrodes. By changing the mask thicknesses, we can control, on demand, the polarization state of the THz pulses from linear polarization through elliptical to circular polarization over a quarter of a THz cycle.

中文翻译：

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产生具有可变椭圆偏振的强亚周期太赫兹脉冲

我们展示了使用特定交叉指状结构的大孔径光电导天线产生具有可变椭圆极化和峰值场超过 80 kV/cm 的强烈亚周期太赫兹 (THz) 脉冲。后者由水平和垂直电极组成，可以产生两个具有正交偏振的准半周期太赫兹脉冲。两个太赫兹脉冲之间的时间延迟是由相位延迟掩模引入的，相位延迟掩模仅覆盖天线的水平电极部分。通过改变掩模厚度，我们可以按需控制太赫兹脉冲的偏振态，在四分之一太赫兹周期内从线偏振到椭圆偏振再到圆偏振。