Abstract-Guiding and emission of milijoule single-cycle THz pulse from laser-driven wire-like targets

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

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 𝜑$\phi$ = 90° (y-z plane), showing asymmetric energy distribution caused by the wire curvature. (c) Simulated electric field evolution (in y-z plane) respectively from the tip target (upper row) and wire (lower row, without curvature at wire end) in time domain. The t=0 has been set to the time when the field front arrives the waveguide end.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-28-10-15258

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.

© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement