阿秒科學前沿開拓與強場量子相干控制研究

李儒新

摘 要：該研究產生更短脈寬、更高光子能量與更高亮度的阿秒相干光源以及原子分子中阿秒電子波包的探測和控制，預期目標主要包括：（1）實現亞飛秒時間尺度和原子級空間尺度內實時觀測和控制電子動力學行為；（2）在多電子弛豫過程中，電子重排、電子-電子碰撞動力學等多電子復雜動力學研究中取得若干突破；（3）揭示有重要意義的化學反應的電子動力學物理本質。探索阿秒脈沖作用下物質的電子動力學新規(guī)律及其應用。開展中紅外激光與氣體介質相互作用產生高次諧波的實驗和理論研究，采用雙色場方法獲得高次諧波連續(xù)譜，為進一步將阿秒脈沖寬度測量和光子能量推進到“水窗”做準備。從理論上深入了解分子結構和反應通道和分子高次諧波之間的聯系，以及和激光參數之間的關系，為實驗研究做準備。獲得了一些系列研究成果，包括發(fā)現太赫茲輻射波形可以通過改變驅動激光脈沖的CEP而實現控制，在光絲等離子體中太赫茲輻射發(fā)生極性反轉，利用周期量級極端超快激光脈沖光場自身的不對稱性獲得增強的太赫茲輻射；發(fā)現基于獨立電子近似的遂穿模型不能解釋次序雙電離中的許多現象等。

關鍵詞：阿秒 超快 量子控制

Abstract： This project work on the generation of the attosecond pulse of shorter pulse width， higher photon energy with higher brightness and the detection and the control of the attosecond electron wavepacket in the atoms and molecules including： （1） achievement of real-time observation and control of the electron dynamics during the sub-femtosecond timescale in the atomic-level spatial scales； （2） detection of the multielectron dynamics， e.g. multi-electron relaxation process， electronic rearrangement， e - e collision dynamics， etc； （3） revealing the electron mechanicsm of the chemical reaction kinetics. To explore the new mechanism and the application of the electron dynamics during its interaction with the attosecond pulse. We have carried out the study of the high order hamonics generation with mid-infrared laser experimentally and theoretically， by using the two color scheme to obtain high harmonic continuous spectrum， for further attosecond pulse width measurement and pushing the photon energy to the "water window" region. We also study the relationship beteween the molecular structures and reaction pathways and molecular harmonics theoretically， as well as the parameters of the laser pulse， for the future experimental study. We have obtained some results including the discovery of terahertz waveform control by changing the CEP of the laser pulse， polarity reversal of the terahertz electric field during the filamentation and the plasma， using the asymmetry of the few-cycle laser pulse to enhance terahertz radiation； discovering that the independent elecctron tunneling model can not explain many phenomena during the sequential double ionization.

Key Words： Attosecond； Ultrafast； Quantum control

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