Signature of multi-channel interference in high-order harmonic generation from N-2 driven by intense mid-infrared pulses

CORC > 上海光学精密机械研究所 > 中国科学院上海光学精密机械研究所 > 强场激光物理国家重点实验室

	Signature of multi-channel interference in high-order harmonic generation from N-2 driven by intense mid-infrared pulses
	Yao JP(姚金平); Xie XH(谢新华); Chen J(陈京); Liu XJ(柳晓军); Cheng Y(程亚); Chu Y(储蔚); Xie HQ(谢红强); Li GH(李贵花)
刊名	物理学报
	2016
卷号	65 期号:22
通讯作者	ya.cheng@siom.ac.cn
中文摘要	通过系统研究氮分子高次谐波产生过程中的电子超快动力学过程,实验上发现在中红外飞秒强激光场驱动下高次谐波谱的截止区附近存在清晰的谐波谱极小值.进一步研究表明谐波谱极小值对应的光子能量强烈依赖于驱动激光脉冲的光强和波长,而与分子取向角无关,由此推断该极小值来源于氮分子最高占据分子轨道和次最高占据分子轨道产生的高次谐波之间的相消干涉.本研究结果将对极端强场条件下多轨道电子超快动力学研究起到积极推动作用.
英文摘要	Recently, three major types of minima (i.e., Cooper-like minimum, two-center interference minimum and multi-channel interference minimum) have been observed in high-order harmonic generation (HHG) spectra. Identification of the origin of the minimum in a HHG spectrum is critical for self-probing of the molecular structures and dynamics, which has been an important subject in attosecond physics. In this paper, we report the investigation of the multi-electron dynamics in HHG from N-2 molecules driven by intense mid-infrared laser pulses. Based on a pump-probe experimental setup, clear spectral minima in the cutoff region of high harmonic spectra from N-2 molecules are observed in measurements with mid-infrared laser pulses at three wavelengths (i.e., 1300, 1400 and 1500 nm). A systematic investigation has been carried out for clarifying the origin of these minima. We carefully measured the spectral minima under three different experimental conditions: 1) different alignment angles of molecules; 2) various peak laser intensities; 3) tunable driving laser wavelengths. Experimental results show that the positions of the spectral minima do not depend on the alignment angles of molecules. In addition, the measured spectral minima shift almost linearly with the laser intensity for all three wavelengths, and the positions of the spectral minima strongly depend on the wavelengths of the driven field. These findings are in conflict with the Cooper-like and two-center interference minima predictions, providing strong evidences on the dynamic multi-channel interference origin of these minima. Besides, we theoretically calculated the positions of multi-channel interference minima by using a classical three-step model and found out perfect agreements between the experimental results and theoretical calculations, which again strongly support the multi-channel interference picture. Moreover, the advantages of the observed dynamic multi-channel interference based on HHG driven by long wavelength lasers are discussed. The long wavelength driver lasers are attractive for not only generating coherent XUV radiation and attosecond pulses, but also investigating structures and dynamics of molecules in strong laser fields.
收录类别	SCI
资助信息	National Basic Research Program of China [2014CB921300, 2013CB922201]; National Natural Science Foundation of China [11127901, 11134010, 61575211, 11304330, 11404357, 61405220, 11274050, 11334009, 61605227]; Shanghai Sailing Program, China [14YF1406100, 1
WOS记录号	WOS:000389598500022
内容类型	期刊论文
源URL	[http://ir.siom.ac.cn/handle/181231/27722]
专题	上海光学精密机械研究所_强场激光物理国家重点实验室
作者单位	中国科学院上海光学精密机械研究所
推荐引用方式 GB/T 7714	Yao JP,Xie XH,Chen J,et al. Signature of multi-channel interference in high-order harmonic generation from N-2 driven by intense mid-infrared pulses[J]. 物理学报,2016,65(22).
APA	姚金平.,谢新华.,陈京.,柳晓军.,程亚.,...&李贵花.(2016).Signature of multi-channel interference in high-order harmonic generation from N-2 driven by intense mid-infrared pulses.物理学报,65(22).
MLA	姚金平,et al."Signature of multi-channel interference in high-order harmonic generation from N-2 driven by intense mid-infrared pulses".物理学报 65.22(2016).