Two Experiments Involving Atomic Rubidium: 4D Excited State Absolute Photoionization Cross Section Measurements and 5S-5D Two-Photon Degenerate Four-Wave Mixing Studies

涉及原子铷的两个实验：4D 激发态绝对光电离截面测量和 5S-5D 双光子简并四波混合研究

• 批准号: 0855560
• 负责人: Alina Gearba
• 金额: $ 33万
• 依托单位: University of Southern Mississippi
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0855560&HistoricalAwards=false
• 关键词: Two; Experiments; Involving; Atomic; Rubidium

This award supports two experimental research projects involving atomic rubidium. The first consists of absolute measurements of the photoionization cross-section of the 4D5/2 excited state of laser-cooled rubidium atoms. Photoionization studies are relevant for sensitive and state-selective detection of trapped atomic and molecular species, as well as for plasma research, including ultracold plasma formation. Excited D states are of particular interest for fundamental tests of atomic theory. Rubidium atoms cooled and trapped in a standard magneto-optical trap will be subsequently excited to the 4D5/2 state via a two-step process and subjected to the photoionizing laser. The photoionization rate will be measured versus several ionizing laser intensities and several wavelengths below the photoionization wavelength from which relative photoionization cross sections will be determined. The photoionization measurements will be subsequently put on an absolute scale by performing accurate measurements of the excited state fraction using a charge transfer technique. The experimental results will be compared for consistency with theoretical calculations. The second project involves theoretical and experimental studies of the 5S1/2-5D5/2 two-photon degenerate four-wave mixing in a rubidium vapor cell. Degenerate four-wave mixing is a high resolution spectroscopy technique which can be used to investigate phenomena such as optical pumping, relaxation, diffusion, collision and quenching processes. Potential applications include phase corrections of aberrant optical wave fronts, optical computing, image processing, pattern recognition and others. The two-photon degenerate four-wave mixing signal will be investigated versus the angle between the probe and the forward pump beams for several rubidium vapor cells mixed with helium buffer gas at various pressures. The experimental results will be used in conjunction with a newly developed theoretical model to obtain numerical values for the 5D5/2 excited state diffusion coefficient.Traditionally, participation of Mississippi?s population in science and engineering has been low. Laser cooling and trapping is one of the most active areas in atomic physics research, and such studies are not performed anywhere else in the states of Mississippi, Alabama and Louisiana. The University of Southern Mississippi has a student population that is 25% African-American and 58% female, which makes the university uniquely positioned to make a difference for women students and, specifically, for minority women in science and engineering. The broader impact of the research is reflected in providing undergraduate and graduate students with experimental research opportunities at the forefront of atomic physics, which in turn, will improve science education. In addition, the research will facilitate extensive involvement in high school outreach and recruitment.

该奖项支持两个涉及原子铷的实验研究项目。第一个包括激光冷却铷原子4D5/2激发态的光离截面的绝对测量。光电离研究与捕获原子和分子物种的敏感和状态选择性检测以及等离子体研究有关，包括超冷等离子体的形成。激发态对于原子理论的基本测试是特别有趣的。铷原子被冷却并被困在一个标准的磁光阱中，随后通过两步过程被激发到4D5/2状态，并受到光电离激光的照射。将测量光电离率与若干电离激光强度和若干低于光电离波长的波长的关系，由此确定相对光电离截面。利用电荷转移技术对激发态分数进行精确测量，从而将光电离测量置于绝对尺度上。实验结果将与理论计算结果进行比较。第二个项目涉及铷蒸汽电池中5S1/2-5D5/2双光子简并四波混频的理论和实验研究。简并四波混频是一种高分辨率的光谱技术，可用于研究光抽运、弛豫、扩散、碰撞和猝灭等现象。潜在的应用包括像差光波前的相位校正、光学计算、图像处理、模式识别等。本文研究了在不同压力下混合氦缓冲气体的铷蒸气池的双光子简并四波混频信号随探针与前向泵浦光束夹角的变化规律。实验结果将与新开发的理论模型结合使用，以获得5D5/2激发态扩散系数的数值。传统上，密西西比的参与？美国科学和工程专业的人口一直很低。激光冷却和俘获是原子物理研究中最活跃的领域之一，在密西西比州、阿拉巴马州和路易斯安那州的其他地方没有进行过这样的研究。南密西西比大学的学生中有25%是非裔美国人，58%是女性，这使得该大学在为女学生，特别是在科学和工程领域的少数族裔女性做出改变方面处于独特的地位。这项研究的广泛影响体现在为本科生和研究生提供在原子物理学前沿进行实验研究的机会，这反过来又将改善科学教育。此外，这项研究将促进广泛参与高中外展和招聘。