Acquisition of Improved Laser System for New Experiments in Atomic Physics

这项拨款提供的设备包括激光系统，将大大增加UMSL原子物理实验室可用的激光辐射的波长范围和质量。这一升级将使该实验室能够最大限度地利用设施和更充分地利用最近开发的实验技术。这些实验都依赖于使用多个激光束对原子进行顺序激发，旨在阐明原子的基本性质。最近的工作利用了这个实验室开发的新的实验技术，以前所未有的精度测量原子参数。其中两种技术，精密直流斯塔克光谱和Floquet光谱，分别基于直流和交流斯塔克效应。两者都使用高度激发的原子来放大原子对电场的响应。第三种技术是为研究受激原子的光电离而开发的，它采用多种激光束偏振方案来获取数据，这些数据与角动量代数相结合，使确定光电离到特定最终角动量状态的截面成为可能。可用激光波长范围的增加将大大扩展实验能力。这种最新的尖端设备将使人们能够比目前更详细地研究更广泛的原子过程。更窄的带宽将允许更精细的光谱特征分辨率，而更高的可用强度将允许激发目前无法访问的原子跃迁。与所有实验室资源一样，所要求的系统将为参与这项研究的许多本科生提供经验和培训。中学教师在暑期培训期间也可获得宝贵的实验室经验。因此，这种设备除了作为实验室工具的内在价值外，还具有教育功能，培训学生和教师如何操作最先进的仪器。＊＊＊

9413457 Leventhal The equipment supplied by this grant consists of laser systems that will significantly increase the wavelength range and the quality of the laser radiation available in the Atomic Physics Laboratory at UMSL. This upgrade will permit maximum utilization of the facilities and fuller exploitation of experimental techniques recently developed in this laboratory. The experiments, all of which rely on sequential excitation of atoms using multiple laser beams, are aimed at elucidating fundamental properties of atoms. Recent work has exploited new experimental techniques developed in this laboratory for measuring atomic parameters with unprecedented accuracy. Two of these techniques, precision dc Stark spectroscopy and Floquet spectroscopy, are based on the dc and ac Stark effects respectively. Both employ highly excited atoms to magnify atomic responses to the fields. A third technique, developed for the study of photoionization of excited atoms, employs a variety of laser beam polarization schemes to acquire data which, in conjunction with angular momentum algebra, make it possible to determine the cross sections for photoionization to specific final angular momentum states. The increased range of available laser wavelengths will greatly expand experimental capabilities. The new state-of-theart device would make it possible to study a wider variety of atomic processes in considerably greater detail than currently possible. The narrower bandwidth would permit finer resolution of spectral features while the higher available intensity would allow excitation of atomic transitions that cannot currently be accessed. As with all laboratory resources, the requested system would provide experience and training for the many undergraduate students who participate in this research. It would also benefit the secondary school teachers who gain valuable laboratory experience during summer training sessions. Thus, this equipment, in addition to its intrins ic value as a laboratory tool, would serve an educational function, training students and teachers in the operation of state-of- the-art instrumentation. ***