Development of New Analyzing Method of Excited States Using Combination of Soft X-Rays and Laser

为了开发新的激发态分析方法，我们在现有的高能角分辨光电子能谱仪和超快激光器的基础上，构建了超快时间分辨光电子能谱系统。利用这个新系统，我们进行了激光抽运的激发态光电子的测量。实验结果与激发态计算结果进行了比较，表明了新光谱的性能。对Ag/Si表面进行了能量分辨和角分辨光电子能谱分析。所得光谱的能量色散曲线表明了新光谱的有效性。我们还安装了平面波动器以获得更高亮度的同步加速器光，并对单色仪系统进行了调谐，以利用同步加速器光和激光高重复频率的优势进行组合实验。我们构建了新的双光子光电子能谱系统。利用该系统，我们成功地测量了n型和p型砷化镓的超快速时间分辨光电子能谱。这一结果对于研究表面光电效应的动力学具有重要的意义。本项目取得的部分成果已在国际会议和期刊上发表。

In order to develop the new analyzing method for excited states, we have constructed the ultra-fast time-resolved photoelectron spectroscopy system based on the existing high energy and angle-resolved photoelectron spectrometer and the ultra-fast laser. Using this new system, we have carried out the measurement of the photoelectrons from the excited-states pumped by laser-light. The experimental results were compared with the calculation of the excited states, indicating the performance of the present new spectroscopy. The energy and angle-resolved photoelectron spectroscopy has been conducted on Ag/Si surfaces. The obtained energy dispersion curves of the bands indicate clearly the validity of the present new spectroscopy. We have also installed the planar undulator to obtain the higher brilliant synchrotron light and tuned up the monochromator system for combination experiments using synchrotron light and laser that have advantage in the high repetition frequency. We have constructed the new two-photon photoelectron spectroscopy system. Using this system we have successfully measured the ultra-fast time-resolved photoelectron spectra on n-and p-type GaAs. The result is very interesting and attractive to investigate the dynamics of the surface photo-voltage effect. A part of the results obtained in the present project has been reported in the international conference and Journals.