Study on the interaction of intense femtosecond laser pulses with nanometre-sized hydrogen clusters

The interaction of intense femtosecond laser pulses with hydrogen clusters has been experimentally studied. The hydrogen clusters were produced from expansion of high-pressure hydrogen gas (backed up to 8\tm10⁶Pa) into vacuum through a conical nozzle cryogenically cooled by liquid nitrogen. The average size of hydrogen clusters was estimated by Rayleigh scattering measurement and the maximum proton energy of up to 4.2keV has been obtained from the Coulomb explosion of hydrogen clusters under 2×10¹⁶ W/cm² laser irradiation. Dependence of the maximum proton energy on cluster size and laser intensity was investigated, indicating the correlation between the laser intensity and the cluster size. The maximum proton energy is found to be directly proportional to the laser intensity, which is consistent with the theoretical prediction.     

Interaction of intense laser pulses with atomic clusters at different gas densities

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 in low 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.     

Sr2准分子吸收离化及混合跃迁的研究

Ｎｄ－ＹＡＧ激光器三倍频泵浦的染料激光激发Ｓｒｌ原子,热二极管探共振离化信号,获得Ｓｒｌ高Ｒｙｄｂｅｒｇ５ｓｎｄＤ２系列双光子激光共振电离谱。实验发现激光汉长调４４０ｎｍ附近时,存在一Ｓｒ２准分子吸收光谱带,同时还观测到了５ｓ５ｐ＾１Ｐ１－５ｓ１１ｄ＾１Ｄ２,５ｓ５ｐ＾１Ｐ１－４ｄ＾２３Ｐ１混合共振跃迁现象。并对这种瞬态准分子的连续吸收光电离背景的形成和混合共振跃迁的机制作了初步探讨,同时对缓冲气     

Interaction of intense laser pulses with atomic clusters at different gas densities

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.     

SrⅠ 5s~(21)S_0-5s4d~1D_2、5s~(21)S_0-5s6d~1D_2单光子电四极矩E2跃迁及其5s~(21)S_0-5s6d~1D_2单光子电四极矩E2前向相干辐射的研究

用染料激光来激发Ｓｒ原子，首次在实验上发现较强的ＳｒⅠ５ｓ２１Ｓ０５ｓ４ｄ１Ｄ２、５ｓ２１Ｓ０５ｓ６ｄ１Ｄ２单光子电四极矩Ｅ２共振跃迁离化信号，并对５ｓ２１Ｓ０５ｓ６ｄ１Ｄ２共振离化时，伴随出现的前向相干辐射进行了判断与分析。     

Dynamics of Coulomb explosion of hydrogen clusters in a high-intensity femtosecond laser pulse

Using Bethe model, the dynamics of the ionization and Coulomb explosion of hydrogen clusters (0.5-5 nm) in high-intensity (1015 -1017 W/cm2) femtosecond laser pulses have been studied theoretically, and the dependence of energy of protons emitted from exploding clusters on cluster size and laser intensity has been investigated. It is found that the maximum proton energy increases exponentially with the cluster size, and the exponent is mainly determined by the laser intensity. For a given cluster size, the maximum proton energy increases with increasing laser intensity and gets saturation gradually. The calculation results are in agreement with the recent experimental observation.     

一种修正RLC串联电路暂态过程τ值的方法

对ＲＬＣ串联电路暂态过程提出一种测量方法,较好的解决了驰豫时间τ的测量值与计算值偏离较大的问题。     

飞秒强激光场中大尺寸氩团簇爆炸机理的实验研究

利用飞行时间谱，研究了在飞秒强激光场（60 fs，2×1016 W/cm2）作用下，大尺寸氩原子团簇Arn（n—=3×103—3×106原子/每团簇）的电离爆炸过程，测量了 团簇爆炸所产生的氩离子的平均能量与团簇尺寸（气体背压）的关系.实验发现，随着气体 背压的升高（团簇尺寸增大），氩离子的平均能量也相应升高.通过分析两个不同几何尺寸 锥形超声喷嘴所产生团簇爆炸后的离子能量，结合Hagena团簇尺寸规律，发现在激光参数保 持不变的情况下，离子的平均能量由团簇尺寸唯一确定.分析表明，团簇尺寸在3×105原 子/每团簇以下时，团簇膨胀的主要机理是库仑爆炸.随着团簇尺寸的进一步增大，团簇膨胀 机理将由库仑爆炸向流体动力学膨胀过渡，在3×105关键词： 原子团簇 飞秒强激光 库仑爆炸 流体动力学膨胀     

Sr原子中5s^21S0—5s6d^1D2双光子共振增强紫外相干辐射

用染料激光来激发Ｓｒ原子，在５ｓ２１Ｓ０５ｓ６ｄ１Ｄ２双光子共振跃迁时，观察到两束前向辐射，经分析认为是一四波混频过程。并分析了这一四波混频过程并对其辐射光强与泵浦光强和Ｓｒ的饱和蒸汽压的关系进行了分析。     

用ICE技术观察和测定镁Mg原子3p9d(J=1,3)的自电离谱

用原子束技术—ＩＣＥ分步激发方案—激光共振电离—飞行时间质谱探测离化信号的方法，观察到了原子束中镁Ｍｇ原子３ｐ９ｄ（Ｊ＝１，３）的自电离谱，并对实验结果进行了讨论和分析。