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Study on Single Attosecond Pulse Generated by Atom Exposed to Two Laser Pulses with the Same Color and Other Pulse

Author: PanHuiLing
Tutor: ZhouXiaoXin
School: Northwest Normal University
Course: Optics
Keywords: Two beams of the same color laser field Half-cycle pulse Mid-infrared field Split-operator Higher harmonic Attosecond pulses
CLC: O562
Type: Master's thesis
Year: 2011
Downloads: 18
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Abstract

Attosecond (1as = 10 ^{-18 s) is a powerful tool to study the dynamic processes of electronic ultrafast processes and atomic and molecular scale electronic attosecond pulse time width of 2.5 femtosecond ultra- short pulses successful implementation of imaging and tracking of atomic inner-shell Auger process, so that people have had a keen interest in attosecond research. By atoms in a strong laser field emission high harmonic attosecond pulses people preferred light source, therefore, the high-order harmonic in recent years has been widespread concern in the subject of research workers. High harmonic single attosecond pulse method: polarization gate technology, two-color laser, three-color laser, multi-color laser, laser half cycle field and the use of chirped laser and static electric field is the role of co-driver atoms single attosecond pulse. In this paper, the split-operator method numerical solution of the one-dimensional helium atom containing the Schr?dinger equation, a helium atom driven by a combination of the two beams of the same color laser field with a half-cycle pulse (Hcps) field emission characteristics of the high-order harmonic. The results show that helium atom driven in such a combined field, the higher harmonic spectrum of the platform region can be greatly expanded, its cut-off position can be extended to the IP 9.6UP, the higher harmonic spectrum through the vicinity of the cutoff position is constructed. pulse width 63as single attosecond pulses. Was found after analysis, the join of the half-cycle pulses, not only the higher harmonic spectrum platform can be extended, and also suppress the electronic long path on the contribution of the higher harmonic. This paper also proposed the use of a combination of the two beams of the same color laser field in the infrared field field-driven one-dimensional helium atoms to produce single attosecond pulse method. Through numerical simulation of the helium atoms under the combined field drive emission characteristics of the higher harmonics, the harmonic spectrum cutoff position can expand to IP 12.6UP, in the high harmonics superimposed on the second platform region within different ranges can single A second pulse, the shortest pulse width of 42as, especially on the front end of the platform region superimposed, can be obtained not only a single A second pulse, with the vicinity of the cutoff position higher harmonic structure compared to the A second pulse, the intensity increased 3 orders of magnitude. After analysis found that the mid-infrared field half-cycle pulse not only makes the platform area of ??high harmonic spectrum extended to also inhibit the contribution of electronic long path of high-order harmonic. The mid-infrared field with a half-cycle pulse different, it not only allows us a wide range of high-order harmonic superposition single attosecond pulse, and pulse width than the half-cycle pulse single attosecond pulse To narrow.}

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