Yushan Zeng, Chuliang Zhou, Liwei Song, Xiaoming Lu, Zhongpeng Li, Yingying Ding, Yafeng Bai, Yi Xu, Yuxin Leng, Ye Tian, Jiansheng Liu, Ruxin Li, and Zhizhan Xu
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| Simulated THz radiation pattern from tip and wire targets. (a) Radiation power pattern from the tip target. The blue line indicates the main lobe direction (which is 17° when 0.18 THz frequency is simulated). The inset represents a frame of electric vector distribution in the transverse cross section. (b) Left: 3D profile of the 0.18 THz frequency radiation power emitted from a 200 µm diameter, 60 mm long wire with a 1 mm diameter semicircle presented at end. Right: A slice distribution of the radiation intensity cutted at |
The miscellaneous applications of terahertz have called for an urgent demand of a super intense terahertz source. Here, we demonstrate the capability of femtosecond laser-driven wires as an efficient ultra-intense terahertz source using 700 mJ laser pulses. When focused onto a wire target, coherent THz generation took place in the miniaturized gyrotron-like undulator where emitted electrons move in the radial electric field spontaneously created on wire surface. The single-cycle terahertz pulse generated from the target is measured to be radially polarized with a pulse energy of a few milijoule. By further applying this scheme to a wire-tip target, we show the near field of the 500 nm radius apex could reach up to 90 GV/m. This efficient THz energy generation and intense THz electric field mark a substantial improvement toward ultra-intense terahertz sources.
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