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本文采用SMT(sknple man’s theory)仔细分析了一维普薛耳-特勒势(P—T势)模型原子在高、低频组合强激光脉冲辐照下电子的动力学行为。并且,在此基础上,着力讨论了电离电子在激光脉冲策动下回核并与之复合从而发射高次谐波的平台结构,采用一种特殊设计的高、低频脉冲组合方案。使谐波发射效率较之于只用单一低频激光时的谐波发射效率提高两个数量级。 相似文献
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一维模型原子在组合脉冲辐照下的高次谐波发射 总被引:2,自引:2,他引:0
本文采用SMT (simple man's theory) 仔细分析了一维普薛耳-特勒势(P-T势)模型原子在高、低频组合强激光脉冲辐照下电子的动力学行为.并且, 在此基础上,着力讨论了电离电子在激光脉冲策动下回核并与之复合从而发射高次谐波的平台结构.采用一种特殊设计的高、低频脉冲组合方案,使谐波发射效率较之于只用单一低频激光时的谐波发射效率提高两个数量级. 相似文献
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用含时薛定谔方程的多态展开(TDMA)方法求解含时薛定谔方程。该方法将含时波函数以基函数展开,通过求解展开系数的一阶微分方程组得到任意时刻的波函数。并将这一方法用于强激光场中谐振子的高次谐波的计算,以HCl分子为例,计算了在脉冲激光作用下高次谐波的产生和对应的激光强度、波长和脉冲宽度。 相似文献
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用含时薛定谔方程的多态展开(TDMA)方法求解含时薛定谔方程.该方法将含时波函数以基函数展开,通过求解展开系数的一阶微分方程组得到任意时刻的波函数.并将这一方法用于强激光场中谐振子的高次谐波的计算,以HCl分子为例,计算了在脉冲激光作用下高次谐波的产生和对应的激光强度、波长和脉冲宽度. 相似文献
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用电容器模型计算了激光打靶过程中由共振吸收诱发的高效谐波,并在此基础上讨论了超短脉冲强激光的高次谐波作为一种短波长相干辐射源的可能性。 相似文献
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在强场近似下,利用Lewenstein模型研究了N2分子在强激光场中发射高次谐波的干涉效应,通过对N2分子产生的高次谐波和分子中单个原子产生高次谐波的比较,表明了干涉效应的存在. 得出随着高次谐波阶数的增加,干涉极小值会随着分子轴与激光偏振方向间夹角的增加而减小,在角度接近900附近时干涉效应消失,与两中心干涉模型预测的趋势一致. 通过分析高次谐波产生的机制和相位随取向角的变化,给出了干涉产生的原因. 相似文献
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强激光和稠密等离子体相互作用产生的三次谐波 总被引:1,自引:1,他引:0
研究了超强激光和均匀及线性梯度高密度等离子体相互作用产生的三次谐波,特别研究了等离子体密度为四倍临界密度时的情形,这可能是用相对论效应产生高效谐波的最佳密度。 相似文献
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LI Xuexin LIU Yaqing ZHAI KanXU Zhizhan HAN Shensheng 《Chinese Journal of Lasers》1997,6(6):539-542
EfectsofPulseDurationsonHighorderHarmonicGenerationLIXuexinLIUYaqingZHAIKanXUZhizhanHANShensheng(ShanghaiInstituteofOpticsan... 相似文献
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l.IntroductionRecentexPerimentshavcdemonstratedthehigh-orderharmonicgenerationinraregasandmoleculargas[1~'j.TherearemanytheoreticalpaPersdealingwithharmonicgen-erationofatom[6~8j,comparativelysPeaking,theoreticalworksabouttheharmonicgen-erationofmolecuIeareless[9j,esPeciallyabouttheevolutionofionizationandharmonicgenerationwiththeinternuclearseparation,andtherelationbetweenionizationandhar-monicgeneration.InthispaPerwegivesomenumericalresultsofdiatomicmolecularionirradiatedbyalinearlyPOlari… 相似文献
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A promising method to both extend the harmonic energy and enhance the harmonic intensity is presented when a He atom is exposed to the combination of a two-color chirped pulse and an ultrashort ultraviolet pulse. It is found that: (1) with the introduction of the two chirps, the harmonic energy has been remarkably extended; (2) by properly adding an ultrashort ultraviolet pulse to this synthesized two-color chirped pulse, the harmonic yield is enhanced by 3 orders of magnitude compared with the two-color chirped case; (3) the harmonic spectrum higher than the 96th order shows an ultrabroad supercontinuum with a 395 eV bandwidth, and the proper superposition over the harmonics directly produced a series of intense 40 as pulses which is 3 orders of magnitude higher than that in the two-color chirped case. 相似文献
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We theoretically investigate high-order harmonic and isolated attosecond pulse generation in a two-color chirped laser field,which is synthesized by a 9 fs/800 nm fundamental chirped pulse and a 9 fs/1600 nm controlling chirped pulse.Our numerical results show that,by using this method,not only is the harmonic cutoff significantly extended to the 948th order harmonic,but also the bandwidth of the supercontinuum spectrum is effectively broadened to about 1342 eV.In addition,due to the introduction of the chirp,the long quantum path is suppressed and only the short one is selected,and then an isolated 28 as pulse with a bandwidth of 155 eV is obtained directly. 相似文献
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We theoretically study the high-order harmonic generation (HHG) from a hydrogen atom in an intense few-cycle chirped fundamental laser in combination with an ultraviolet (uv) controlling pulse.The high-order harmonic spectrum is calculated by solving the time-dependent Schr¨odinger equation using the split-operator method.In our calculation,we present the difference of the high-order harmonic spectrum from one-dimensional (1D) model hydrogen atom and three-dimensional (3D) real hydrogen atom.We found that the plateau of the high-order harmonic generation from the 1D case and 3D case are all extended effectively to I p + 35U p due to the presence of the chirped laser pulse and the HHG supercontinuum spectrum is generated by adding an ultraviolet controlling pulse at a proper time,but the efficiency of the HHG for 3D case is more higher at the near cut-off region than the 1D case.Therefore,the generation of the attosecond pulse by synthesizing the harmonics near cut-off region have some slight differences between 1D and 3D simulations.As a real 3D case study,we show that an isolated 18 as pulse with a bandwidth of 232.5 eV is generated directly by optmizing the combination laser fields. 相似文献
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We perform an experimental study on high-order harmonic generation (HHG) of aligned acetylene molecules induced by a 35-fs 800-nm strong laser field, by using a home-built HHG spectrometer. It is observed that the molecular HHG probability declines with increasing the laser ellipticity, which is in consistence with the deduction from the well-known tunneling-plus-rescattering scenario. By introducing a weak femtosecond laser pulse to nonadiabatically align the molecules, we investigated the molecular orbital effect on the HHG in both linearly and elliptically polarized driving laser fields. The results show that the harmonic intensity is maximum for the molecular axis aligned perpendicularly to the laser electric field. It indicates that both the highest occupied molecular orbitals (HOMO) and HOMO-1 contribute to the strong-field HHG of acetylene molecules. Our study should pave the way for understanding the interaction of molecules with ultrafast strong laser fields. 相似文献
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The isotopic effect on the generation of the molecular high-order harmonics is studied by numerically solving the one-dimensional time-dependent Schrödinger equation when the model hydrogen molecule ions/hydrogen deuterium molecule ions are exposed to an intense laser pulse. To explain the effect more clearly, not only the ionization probabilities but also the electron–nuclear probability density distributions and time-frequency profiles are calculated. The results show that more intense harmonics are generated in the asymmetric diatomic molecule ions/hydrogen deuterium molecule ions than those of hydrogen molecule ions. Moreover, the interference minimum in the harmonic spectra is investigated by adjusting the laser intensity and the initial vibrational state. It is shown that the interference minimum is sensitive to the laser intensity and the initial vibrational level for hydrogen molecule ions; in contrast, it is only dependent on the initial vibrational level for hydrogen deuterium molecule ions. 相似文献
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In this paper, we theoretically investigate high-order harmonic generation (HHG) from a helium atom prepared in a coherent superposition state in a two-color laser field. Numerical results show that the emission efficiency of the harmonic spectrum in a coherent superposition state is enhanced by approximately eight orders of magnitude compared with the case of the ground state. In addition, the effect of the initial population of the excited state on the HHG is presented to reveal the physical origin of the enhancement of HHG. By adjusting the laser parameters of the driving pulse, such as the chirping parameter, the relative phase, and the intensity of the driving pulse, an ultrabroad continuum with a width of 275 eV can be observed. Finally, an isolated 12-as pulse is generated after phase compensation. 相似文献