CAREER:Laser Cooling and Trapping of Beryllium: Frozen Plasmas and Precision Measurements

University Of Alabama At Birmingham, Birmingham AL

Investigators

Abstract

This CAREER award supports investigation of berillium (Be) as a new candidate element for the next generation of optical atomic clocks, as well as for producing an ultracold neutral plasma -- an ultracold gas of ions and electrons. Atomic clocks have been instrumental in the advancement of science and technology in the twentieth century, leading to innovations such as global positioning, advanced communications, and tests of fundamental theories of particle physics. A next generation optical atomic clock would extend the capabilities of these systems and will enable enhanced security for data routing and communications, advanced earth and space time-based navigation, and ever more precise testing of Einstein's Theory of General Relativity. Ultracold neutral plasmas (UCNPs) are laser produced plasmas that stretch the boundaries of traditional plasma physics. However, studies of these table-top ultracold systems are promising to greatly improve our understanding of much hotter and denser plasmas thought to occur in many astrophysical systems. The goal of this project is to laser cool, trap and photo-ionize neutral atomic beryllium for its potential use as an optical frequency standard, and to produce a UNCP at a sufficiently low temperature for ionic crystals to form inside the system, virtually freezing the plasma. This award will also make it possible to attract and retain more underrepresented minority students to physics studies. The project will involve minority graduate, undergraduate, and high school students via existing Univ. of Alabama - Birmingham programs to participate in research projects in the Simien Spectroscopy and Laser Cooling group. Additional outreach activities will aim to get K-12 students interested in science and engineering by performing physics and chemistry demonstrations at local schools in the region. This project is an experimental program directed towards investigation of spectroscopic, laser cooling, and photoionization properties of atomic beryllium as it relates to atomic clocks and ultracold neutral plasmas. Be is an alkaline earth element with a simple internal structure which provides for electric-dipole and intercombination transitions in the optical regions for both neutral atoms and ions. It is a promising candidate for next generation frequency standards and for laser cooling, trapping, and photo-ionization to produce an ultracold plasma. In particular, the spectroscopic studies will involve measurements of the hyperfine structure of strong electric dipole transitions. The objective of this study is to determine Be hyperfine constants, which define the ordering of the hyperfine peaks and contributions to the energy shifts from the magnetic dipole and electric quadrupole interactions. The determination of this spectroscopic property is necessary for implementing laser cooling and trapping of beryllium. In addition, laser cooling and trapping will be used to create a magneto-optical trap as the first step towards performing precision measurements on the intercombination lines. It will also be used for photoionization studies for generation of a Be based frequency standard and an ultracold neutral plasma that can be efficiently laser cooled into the strongly coupled regime. This project is jointly funded by the Plasma Physics program, the Atomic, Molecular and Optical Experimental Physics program, and the Established Program to Stimulate Competitive Research (EPSCoR). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.