Gildenburg V B, Vvedenskii N V
Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950, Russia.
Phys Rev Lett. 2007 Jun 15;98(24):245002. doi: 10.1103/PhysRevLett.98.245002.
A new ("linear-parametric") mechanism of a direct conversion of an ultrashort laser pulse into terahertz radiation is suggested. The conversion is due to the ionization-induced excitation and the subsequent electromagnetic emission of the superluminous polarization wave created by the axicon-focused laser pulse. For a few-cycle pulse with an optimum carrier-envelope phase, the considered mechanism is found to be much more effective than the alternative one based on the excitation of plasma oscillations in the laser wakefield by the ponderomotive force and able to provide THz radiation of the gigawatt power level with the use of moderate optical intensity (approximately 10(14)-10(15) W/cm2).
提出了一种将超短激光脉冲直接转换为太赫兹辐射的新型（“线性参数”）机制。这种转换是由于电离诱导激发以及由轴棱锥聚焦激光脉冲产生的超发光极化波随后的电磁辐射。对于具有最佳载波包络相位的几个周期的脉冲，发现所考虑的机制比基于有质动力在激光尾场中激发等离子体振荡的替代机制有效得多，并且能够在使用中等光强（约10(14)-10(15)W/cm2）的情况下提供千兆瓦功率水平的太赫兹辐射。
