Precision Laser Studies of Basic Atoms and Nuclei

University Of North Texas, Denton TX

Investigators

Abstract

This research develops laser technology and precision laser techniques and applies them to the study of helium fine structure and the precise determination of hydrogen and helium nuclear sizes. Electron-electron interactions are central to the structure of the matter around us, and experimental and theoretical studies on helium fine structure provide among the most precise tests of our fundamental understanding of this interaction. Helium has the complexities of the electron-electron interaction, but is nevertheless sufficiently simple that the precision of fine structure theory is not currently limited by numerical approximations, but by the fundamental quantum electrodynamics of this interaction. This fine structure work in helium also leads to a precise determination of the fine structure constant alpha, which then provides a consistency check on other precision determinations of this fundamental constant and the physics that they involve. Isotopic shifts in these experimental results allow the charge radii of helium-3 and tritium to be determined and compared to predictions of few-nucleon theory and the underlying description of the nuclear force. This work provides experimental benchmarks with which to test (1) the atomic theory and computation of electron-electron interactions in helium, the simplest multi-electron atom, and (2) the nuclear interactions and computations that predict the observed size of few-nucleon nuclei. The tabletop experiments provide high school, bachelors, masters, doctoral, and post-doctoral students experience and training in developing new laser sources and optical techniques. They then apply them to test our current understanding of these basic physical systems. Particular experimental effort is being undertaken to develop efficient and convenient frequency conversion of laser light from the infrared to the blue and UV portions of the electromagnetic spectrum. Progress in this area has potential benefits to broad areas of science and technology, from semiconductor wafer inspection to biomedical instrumentation.