论文标题
基于超快速动量显微镜和稀疏驱动相检索的有效轨道成像
Efficient orbital imaging based on ultrafast momentum microscopy and sparsity-driven phase retrieval
论文作者
论文摘要
我们为轨道层析成像提供了能量分辨的光电子动量图，这些图已通过新颖有效的飞行时间动量显微镜设置收集。该设置与0.5 MHz的台式飞秒极端耗分型光源相结合，该光源可以实现数据收集的前所未有的速度，并为未来的时间分辨轨道成像实验铺平了道路。此外，我们在轨道成像的数据分析过程中迈出了重要的一步，并针对所需的相检索问题提出了一种稀疏驱动的方法，该方法仅使用轨道中的非零像素的数量。在这里，不需要对对象支持的了解，并且可以从测量数据中轻松确定稀疏编号。该稀疏性约束用于放松的平均交替反射算法，可为我们的实验以及无噪声和嘈杂的模拟光电子动量映射数据提供快速，可靠的相位检索。
We present energy-resolved photoelectron momentum maps for orbital tomography that have been collected with a novel and efficient time-of-flight momentum microscopy setup. This setup is combined with a 0.5 MHz table-top femtosecond extreme-ultraviolet light source, which enables unprecedented speed in data collection and paves the way towards time-resolved orbital imaging experiments in the future. Moreover, we take a significant step forward in the data analysis procedure for orbital imaging, and present a sparsity-driven approach to the required phase retrieval problem, which uses only the number of non-zero pixels in the orbital. Here, no knowledge of the object support is required, and the sparsity number can easily be determined from the measured data. Used in the relaxed averaged alternating reflections algorithm, this sparsity constraint enables fast and reliable phase retrieval for our experimental as well as noise-free and noisy simulated photoelectron momentum map data.
