Abstract -Attosecond synchronization of terahertz wave and high-harmonics

Zhihui Lü, Dongwen Zhang, Chao Meng, Xiyu Du, Zhaoyan Zhou, Yindong Huang, Zengxiu Zhao and Jianmin Yuan
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zhao.zengxiu@gmail.com jmyuan@nudt.edu.cn
Department of Physics, National University of Defense Technology, Changsha 410073, People's Republic of China 

http://m.iopscience.iop.org/0953-4075/46/15/155602/

Argon atom ionizing in the ultrafast two-colour field has been used to investigate the physical mechanism of terahertz (THz) generation. We measured simultaneously pulse energies of THz and high-harmonics as the phase delay between the fundamental and its second harmonic was varied. The optimal phase delay of THz generation is determined according to the inherent attochirp of the emitted high-harmonics. The dynamic analysis of the tunnelling electron wave packet driven by the Coulomb–laser coupling shows that laser-assisted soft collisions of the electron wave packet with the atomic core play a key role. It is demonstrated that the rescattering process, being indispensable in high-harmonic generation processes, dominates THz wave generation as well in a more elaborate way.

Abstract-Synchronizing Terahertz Wave Generation with Attosecond Bursts

Dongwen Zhang, Zhihui Lü, Chao Meng, Xiyu Du, Zhaoyan Zhou, Zengxiu Zhao^*, and Jianmin Yuan^† 
Department of Physics, National University of Defense Technology, Changsha 410073, People’s Republic of China

We perform a joint measurement of terahertz waves and high-harmonics generated from argon atoms driven by a fundamental laser pulse and its second harmonic. By correlating their dependence on the phase delay between the two pulses, we determine the generation of THz waves in tens of attoseconds precision. Compared with simulations and models, we find that the laser-assisted soft collision of the electron wave packet with the atomic core plays a key role. It is demonstrated that the rescattering process, being indispensable in high-harmonic generation processes, dominates THz wave generation as well in a more elaborate way. The new finding might be helpful for the full characterization of the rescattering dynamics.

Abstract-Ticking terahertz wave generation in attoseconds

http://arxiv.org/abs/1206.6256

Dongwen Zhang, Zhihui Lü, Chao Meng, Xiyu Du, Zhaoyan Zhou, Zengxiu Zhao, Jianmin Yuan

(Submitted on 27 Jun 2012)

We perform a joint measurement of terahertz waves and high-order harmonics generated from noble atoms driven by a fundamental laser pulse and its second harmonic. By correlating their dependence on the phase-delay of the two pulses, we determine the generation of THz waves in tens of attoseconds precision. Compared with simulations and models, we find that the laser-assisted soft-collision of the electron wave packet with the atomic core plays a key role. It is demonstrated that the rescattering process, being indispensable in HHG processes, dominant THz wave generation as well but in a more elaborate way. The new finding might be helpful for the full characterization of the rescattering dynamics.

Comments:	4 figures
Subjects:	Atomic Physics (physics.atom-ph)
Cite as:	arXiv:1206.6256v1 [physics.atom-ph]