Mairesse Y, de Bohan A, Frasinski L J, Merdji H, Dinu L C, Monchicourt P, Breger P, Kovacev M, Taïeb R, Carré B, Muller H G, Agostini P, Salières P
Commissariat à l'Energie Atomique, DRECAM/SPAM, Centre d'Etudes de Saclay, 91191 Gif-sur-Yvette, France.
Science. 2003 Nov 28;302(5650):1540-3. doi: 10.1126/science.1090277.
Subfemtosecond light pulses can be obtained by superposing several high harmonics of an intense laser pulse. Provided that the harmonics are emitted simultaneously, increasing their number should result in shorter pulses. However, we found that the high harmonics were not synchronized on an attosecond time scale, thus setting a lower limit to the achievable x-ray pulse duration. We showed that the synchronization could be improved considerably by controlling the underlying ultrafast electron dynamics, to provide pulses of 130 attoseconds in duration. We discuss the possibility of achieving even shorter pulses, which would allow us to track fast electron processes in matter.
通过叠加强激光脉冲的几个高次谐波可以获得亚飞秒光脉冲。倘若谐波是同时发射的，增加其数量应会产生更短的脉冲。然而，我们发现高次谐波在阿秒时间尺度上并不同步，从而为可实现的X射线脉冲持续时间设定了下限。我们表明，通过控制潜在的超快电子动力学，可以显著改善同步，以提供持续时间为130阿秒的脉冲。我们讨论了实现更短脉冲的可能性，这将使我们能够追踪物质中的快速电子过程。
