Abstract-Terahertz radiation enhanced by target ablation during the interaction of high intensity laser pulse and micron-thickness metal foil

Physics of Plasmas

 Siyuan Zhang, Jinqing Yu, Yinren Shou,  Zheng Gong, Dongyu Li, Yixing Geng, Weimin Wang,  Xueqing Yan,Chen Lin,

The schematic of the setup. A linearly polarized laser pulse (red) generates energetic electrons when it propagates in the preplasma (gray) caused by the ablation laser pulse (pink). When these fast electrons cross the rear target surface, THz pulses are produced via the transition radiation.

https://aip.scitation.org/doi/abs/10.1063/1.5125611

When an ultra-intense relativistic laser is irradiated on a solid target, terahertz (THz) pulses can be generated by coherent transition radiation when the laser-driven electron beams cross the rear surface of the target. The radiation energy depends on the number and energy of the electrons. By introducing a milli-joule picosecond ablation laser pulse, an underdense preplasma with a scale length of micrometers is generated at the front surface of the target. Electron beams with more charge and higher energy can be produced during the interaction between the following main laser pulse and the preplasma, which enhance the THz radiation and affect the radiation angle. Two dimensional particle-in-cell simulations demonstrate the improvement of electron beams and a nearly tenfold enhancement of THz radiation energy is observed.