Abstract There are two physical phenomena in a strong laser intensity. One is the high-order harmonic emission; the other is x-ray emission from optical-field ionized plasmas. The experiment of conversion from high-order harmonics to x-ray emissions was given with a 105fs Ti:sapphire laser by adjusting laser intensities. The ingredient in plasma was investigated by the numerical simulations. Our experimental results suggested that the free electrons have detrimental effects on harmonic generation but are favourable for x-ray emission from optical-field ionized plasmas. If we want to obtain more intense harmonic signals as a coherent light source in the soft x-ray region, we must avoid the production of free electrons in plasmas. At the same time, if we want to observe x-rays for the development of high-repetition-rate table-top soft x-ray lasers, we should strip all atoms in the plasmas to a necessary ionized stage by the optical-field-ionization in the field of a high-intensity laser pulse.
Received: 16 May 2002
Revised: 03 January 2003
Accepted manuscript online:
PACS:
42.65.Ky
(Frequency conversion; harmonic generation, including higher-order harmonic generation)
Fund: Project supported by the National High Technology Development Programme of China (Grant No 863-804-7-10(J)), and the National Natural Science Foundation of China (Grant No 60078010).
Cite this article:
Wang Qi (王骐), Chen Jian-Xin (陈建新), Xia Yuan-Qin (夏元钦), Chen De-Ying (陈德应) Experimental study of conversion from atomic high-order harmonics to x-ray emissions 2003 Chinese Physics 12 524
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