Construction and Characterization of a Neutral Hg Magneto-Optical Trap and Precision Spectroscopy of the 6¹S₀ - 6³P₀ Hg¹⁹⁹ Clock Transition

Abstract

In this dissertation I present theory and experimental results obtained in the Jones research group at the University of Arizona investigating the feasibility of neutral Hg as a candidate for an atomic clock. This investigation includes laser-cooling and trapping of several neutral Hg isotopes as well as spectroscopy of the 6¹S₀ - 6³P₀ doubly forbidden clock transition in neutral Hg¹⁹⁹. We demonstrate precision spectroscopy of the ground state cooling/trapping transition of neutral mercury at 254 nm using an optically pumped semiconductor laser (OPSL). This demonstration exhibits the utility of optically pumped semiconductor lasers (OPSLs) in the field of precision atomic spectroscopy. The OPSL lases at 1015 nm and is frequency quadrupled to provide the trapping light for the ground state cooling transition. We get up to 1.5 W single-frequency output power having a linewidth of < 10 kHz in the IR with active feedback. We frequency quadruple the OPSL in two external cavity stages to produce up to 120 mW of deep-UV light at 253.7 nm. I give a detailed characterization of the construction and implementation of the neutral Hg vapor cell magneto-optical trap (MOT). The trap can be loaded in as quickly as 75 ms at background vapor pressures below 10⁻⁸ torr. At reduced background pressure (< 10⁻¹⁰ torr) the loading time approaches 2 sec. We describe construction and stabilization of a laser resonant with the Hg¹⁹⁹ clock transition and the methods employed to find and perform the experimentally delicate spectroscopy of the clock transition. We present experimental results and analysis for our initial spectroscopy of the 6¹S₀- 6³P₀ clock transition in the Hg¹⁹⁹ isotope of neutral mercury.