## Honors Theses

2021

#### Document Type

Honors Thesis (Open Access)

#### Department

Colby College. Physics and Astronomy Dept.

Charles Conover

#### Abstract

This thesis presents measurements of the lifetimes of 5p1/2 and 5p3/2 of K39 via exciting a cloud of K39 atoms in a magneto-optical trap by a linearly-polarized pulse of 405 nm light followed polarization-specific, time-resolved fluorescence detection. We find that $\tau_{5p1/2} =$ 138.8 $\pm$ 1.6 ns, which is consistent with past measurements \cite{triumf}, \cite{berends} and calculations \cite{safranova}. The $\tau_{5p3/2}$ measurement is naturally more involved since quantum beats due to hyperfine and Zeeman effect are present. Our observation of $\tau_{5p3/2} =$ 137.6 $\pm$ 3.1 ns and $\tau_{5p3/2} =$ 136.0 $\pm$ 2.4 ns, obtained from two slightly different approaches, are compared against past measurements \cite{berends}, \cite{Svanberg_1971}, \cite{Ney1969}, \cite{schmeider} and theoretical calculations in \cite{safranova}. We determine that future work is needed to reduce the uncertainty in our measurement and resolve the discrepancy in the literature.

#### Keywords

lifetime measurements, single-photon counting, magneto-optical trap, quantum beats, hyperfine structure, Zeeman effect

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