激光参数影响太赫兹辐射的数值模拟

Numerical simulation on effect of laser parameters on terahertz radiation

利用2维PIC程序模拟了聚焦激光脉冲垂直入射非均匀等离子体,在界面激发超强太赫兹辐射的物理过程,研究了激光强度、脉宽和焦斑半径对太赫兹辐射功率和频率的影响,并和模式转换理论作了对比。结果表明:激光强度是影响太赫兹辐射功率的主要因素;当脉宽在等离子体波长附近时,激起的静电波振幅最大,此时对应的太赫兹辐射最强;同时存在一个最优的焦斑半径,使得辐射功率最大。

THz radiation excited from the laser-plasma interaction was numerically simulated using a 2D3V PIC code, and the effects of laser parameters on the THz radiation power and frequency were compared with the results of the linear mode conversion theory. The PIC simulation results show that the laser pulse intensity dominates on the THz radiation power the optimal pulse width for the strongest electrostatic wave with THz radiation is around the plasma wavelength. Meanwhile, there is an optimal focused radius which is around 0.3Sλpo for the strongest radiation.