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41.
1 Introduction Themethodsthatcanmeasurethephaseandthe pulsedurationmainlyincludetheFROG[1] (frequency -resolvedopticalgating)andtheSPIDER[2 ] (spectral phaseinterferometryfordirectelectric fieldreconstruction) .FROG[1] usestheunknownpulseitselfasatime delayed ga… 相似文献
42.
X射线荧光全息术,通过记录样品的荧光全息图并利用计算机重构,能够得到晶体内部原子的三维排列信息,这对于材料科学将有着非凡的意义.理论上,在一个X射线荧光全息实验中,实验者必须在4π立体角范围内高角度分辨率地探测荧光的强度,才能得到高空间分辨率的三维的原子像.但在实际的X射线荧光全息实验中,因为实验的装置安排限制,不允许探测到整个球面上的荧光强度振幅.因为取样范围的不完全而引起的全息信息的损失将直接导致重构的原子像失真.本文通过数值模拟在不同角度范围和取样步长情况下铁单晶的X射线荧光全息图并对其进行数字重构,研究了记录全息图的角度范围及取样步长对重构得到的原子像的影响.方位角范围的不完全导致原子像在x和y方向上被拉长,而且导致原子像的亮度不均匀.而极角范围的不完全则导致了原子像在z方向上被拉长.至于步长的影响,则是可以忽略的,如果步长不是太大的话. 相似文献
43.
The interaction of intense femtosecond laser pulses with rare gas clusters was studied experimentally,the time-of-flight spectra of ions from exploding clusters at different gas densities have been measured. It is found that while the relative components of ions inlow and high energy of the ion energy spectrum decrease with the increase of the gas density,the average ion energies are the same for different gas densities,which indicates that the effect of gas density on laser-cluster interaction is not important under our experimental conditions. 相似文献
44.
To measure the characteristics of ultrashort laser pulse, an apparatus design and its data processing based on SPIDER are put forward. In this method, the data processing is very simple and only basic mathematic calculation is needed. Furthermore, the pulse to be measured is avoided to pass through any dispersive structure before it arrives at the nonlinear crystal in the designed apparatus. In such a design, the pulse duration less than 10fs can be measured precisely. 相似文献
45.
In our recent Letter, we made some mistakes in our calculation. The interference between the two pulses should be considered and the spectrum will contain fringes. However, the two-colour field assisted XUV photoionization remains valid and the conclusion in the Letter remains correct. 相似文献
46.
Phase-matched high-order harmonic generation in Ar gas-filled cell is investigated experimentally. We obtain phase-matched 27th order harmonic driven by a commercially available solid-state femtosecond laser system at 0.55 mJ/pulse energy level and 1-kHz repetition rate. Moreover, we find that the spatial distribution of intensity of high-order harmonics is flat-top profile other than a Gaussian one under the condition of optimized conversion efficiency in the static gas cell. 相似文献
47.
Effect of the Initial Laser Phase on the Interaction Between Relativistic Electron and Ultra-Intense Laser Field in a Strong Uniform Magnetic Field 下载免费PDF全文
We investigate the influence of the initial laser phase on the interaction between relativistic electron and ultraintense linear polarized laser field in a strong uniform magnetic field. It is found that the dynamic behaviour of the relativistic electron and the emission spectrum varies dramatically with different initial laser field phases.The effect of changing initial phase is contrary in the two parameter regions divided by the resonance condition.The phase dependence of the electron energy and velocity components are also studied. Some beat structure is found when the initial laser phase is zero and this structure is absent when the initial laser phase is a quarter of a period. 相似文献
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We demonstrate a pulse compression technique through filamentation in an argon-filled cell. By using a pair of chirped mirrors for dispersion compensation, we have successfully compressed the 53 fs pulse to 15 fs with good spatial qualities and good pulse stability. The total transmitted efficiency is more than 75%. The influence of the experiment parameters to the compressed pulses is also studied experhnentally. 相似文献