Exploitation of femto-second time resolved ultraviolet magnetic circular dichroism photoelectron emission microscopy

我们在紫外（UV）磁圆二色性（MCD）光电子发射显微镜（PEEM）的基础上，利用可调谐紫外激光器，研制了空间分辨率约为50nm的新型磁显微镜，并进一步发展了飞秒时间分辨泵浦-探测显微镜。这种性能比使用第三代同步辐射光源的X射线MCD PEEM的类似方法优越上级得多，因为这种方法允许实验室内实验和千倍更快的时间分辨能力。此外，我们成功地观察到双光子紫外MCD PEEM图像具有高灵敏度。我们还研究了来源的MCD灵敏度的巨大增强附近的功函数阈值，通过使用角分辨光电子能谱。

We invented a novel magnetic microscope, based on ultraviolet (UV) magnetic circular dichroism (MCD) photoelectron emission microscope (PEEM) with a spatial resolution of ～50nm using tunable UV lasers, and further developed a femto-second time-resolved pump-and-probe mciroscope. This performance is much superior to a similar method of X-ray MCD PEEM using a third-generation synchrotron radiation light source since this method allows in-laboratory experiments and thousand times faster time resolving power. Moreover, we succeeded in the observation of two-photon UV MCD PEEM images with a high sensitivity. We also investigated the origin of the huge enhancement of the MCD sensitivity in the vicinity of the work function threshold by using the angle-resolved photoemission spectroscopy.