汞离子光频标系统中同位素选择性光电离及离子装载的研究

Mercury ion optical frequency standard system is one of the most accurate frequency standard systems in the world in nowad.ays, and is one of the most promissing candidite for definition of the second in next generation. Now the common method used to obtain mercury ion is to resolve the mercuric oxide power into mercury atom gas by heating, and then ionize the mercury atom with electron bombardment.This method has sevreral disadvantages, such as low ionizing efficiency, no selectivity for various isotopes, and contamnation of the ion trap system. In this programme we propose to study the photoionization scheme: pumping the mercury atom to an excited state with 253.7nm laser, and then ionizing the excited atom with 194nm laser, which is already used as cooling and detection laser in mercury ion optical frequensy standard systems. Based on it we will carry out researches about broadening effects of the photoionizing spectrum, as well as dynamics of ion loading and loss. This scheme has a lot of advanges, such less accumulated stray electric field, longer lifetime of the system, and isotope selectivety. In addition, it will be beneficial to the research of entanglement enhanced multi ion frequency standard in the future.

汞离子光频标系统是目前国际上精度最高的频标系统之一，也是下一代秒定义的候选之一。目前产生汞离子的常用方法是将氧化汞粉末加热分解产生汞原子蒸气，再用电子枪轰击使得汞原子电离。这种方案存在一些不足之处，如电离效率较低，无法选出特定的同位素，而且电子枪容易污染离子阱系统，影响系统寿命。本项目拟研究汞离子的激光电离方案：用253.7nm紫外激光将汞原子泵浦到激发态，再用汞离子光频标系统中作为冷却光的194nm深紫外激光将处于激发态的汞原子电离。在此基础上研究导致电离谱展宽的各种物理效应并进行抑制，分析离子装载和损耗的动力学演化过程。本方案不但有助于减小离子阱系统中的杂散势场，延长系统寿命，而且能高效的产生特定同位素离子，有助于未来开展基于纠缠增强的多离子频标方案的研究。

汞离子光频标系统是目前国际上精度最高的频标系统之一，也是下一代秒定义的候选之一。目前产生汞离子的常用方法是将氧化汞粉末加热分解产生汞原子蒸气，再用电子枪轰击使得汞原子电离。这种方案存在一些不足之处，如电离效率较低，无法选出特定的同位素，而且电子枪容易污染离子阱系统，影响系统寿命。本项目拟研究汞离子的激光电离方案：用253.7nm紫外激光将汞原子泵浦到激发态，再用汞离子光频标系统中作为冷却光的194nm深紫外激光将处于激发态的汞原子电离。在此基础上研究导致电离谱展宽的各种物理效应并进行抑制，分析离子装载和损耗的动力学演化过程。本方案不但有助于减小离子阱系统中的杂散势场，延长系统寿命，而且能高效的产生特定同位素离子，有助于未来开展基于纠缠增强的多离子频标方案的研究。