X射线相衬成像

本文介绍了近年来X射线位相衬度成像技术的发展状况，详细论述了X射线干涉相衬、衍射增强相衬，类同轴相衬和数字位相重构等几种典型的成像原理，讨论了影响成像衬度与分辨率的若干因素，并对位相成像的发展趋势作了展望。     

Coherent population transfer with Coherent population transfer with chirped few-cycle laser pulses in an excited-doublet four-level system

The efficient excitation to particular states has attracted much attention in both physics and chemistry[1-10]. The stimulated Raman adiabatic passage technique for pop- ulation transfer has been implemented with continuous or narrow band laser pulse (nanosecond time scale)[1], but the requirement for large pulse areas seems to advise against the use of short pulse lasers. However, the use of ultrashort laser pulse may have some distinct advan- tages, such as producing high energy frequencies,…     

消除长程电磁场对电子全息术的电子参考波的影响

测量微电磁场的分布是电子全息术的一个重要应用领域。在许多情况下,待测电磁场不是局限于样品内,而是空间弥散的。这样不仅影响物波,而且也影响参考波,使参考波的位相发生变化,因而使重现电子全息图产生失真,这即是长程电磁场对参考波的位相扰动问题。采用级数展开法,用一个级数展开式来近似电子波的相位函数,展开式的系数用实验数据来确定,并在此过程中消除参考波的位相扰动,从而精确恢复电子波的位相函数,以达到精确测量的目的。     

类Be氩离子振子强度和跃迁光谱

研究了类Ｂｅ氩离子内壳层电子光电离的激发能级，寿命和辐射速率，谱线波长和振子强度，并给出了位于“水窗”波段的谱线波长和谱线强度。     

超短脉冲激光在均匀等离子体中的一维演化

研究了均匀等离子体中超短脉冲激光在传输过程中的脉宽、峰值功率随时间，空间变化的解析式，结果表明，对于２５ｆｓ左右的超短脉冲，由等离体色散引起的脉宽变长及峰值功率降低效应是明显的。     

非同轴双束激光产生的等离子体辐射

采用非同轴双束激光，可得到时空差可控的二束不同性质的等离子体，实现在绝对同等条件下研究多束等离子体辐射的空间非均匀性和等离子体喷射对线加宽的影响。实验结果显示出在最简单的实验装置上实现等离子体强Ｘ射线泵浦Ｘ射线激光方案的可能性。     

钛宝石再生放大器实验研究

分析了啁啾脉冲在钛宝石再生放大器中的能量增益与泵浦光及信号光光束口径的关系。并用不同能量的调Ｑ倍频ＮｄＹＡＧ激光器的５３２ｎｍ光为泵浦光，测量了２ＴＷ钛宝石激光系统中钛宝石再生放大器在无注入信号脉冲时和有注入信号脉冲时的脉冲建立时间及相应的输出能量大小。再生放大器的增益为２×１０７。     

Generation of near transform-limited ultrashort laser pulses in kilohertz chirped-pulse amplification system by compensating high order phase distortions

The effects of gain narrowing and high order dispersions on the pulse duration in our kilohertz chirped-pulse amplification system have been compensated experimentally. Using an acousto-optic programmable dispersive filter (AOPDF), the spectral full-width at half-maximum (FWHM) is expanded from 30 to 50 nm. Stable laser pulses with the duration of 30 fs (FWHM), which is 1.07 times Fourier-transform-limitation, have been acquired by pre-compensating the high order phase distortions using the phase measured by spectral phase interferometry for direct electric-field reconstruction (SPIDER).     

A spectroscopic method for determining thickness of quartz wave plate

A spectroscopic method to determine thickness of quartz wave plate is presented. The method is based on chromatic polarization interferometry. With the polarization-resolved transmission spectrum (PRTS) curve, the phase retardation of quartz wave plate can be determined at a wide spectral range from 200 to 2000 nm obviously. Through accurate judgment of extreme points of PRTS curve at long-wave band, the physical thickness of quartz wave plates can be obtained exactly. We give a measuring example and the error analysis. It is found that the measuring precision of thickness is mainly determined by the spectral resolution of spectrometer.     

利用掠入射消象差光栅光谱仪分析LiF等离子体光谱

本文报导利用无象差掠入式光栅谱仪拍摄激光等离子体发射的极紫外光谱。