Mm-wave Spectroscopy And Determination Of The Radiative Branching Ratios Of 11bh For Laser Cooling Experiments

Truppe, Stefan

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https://hdl.handle.net/2142/50827 Copy

Description

Title

Mm-wave Spectroscopy And Determination Of The Radiative Branching Ratios Of 11bh For Laser Cooling Experiments

Author(s)

Truppe, Stefan

Contributor(s)

• Tarbutt, Michael
• Hinds, Ed
• Hendricks, Richard James
• Holland, Darren

Issue Date

2014-06-19

Keyword(s)

Cold/Ultra-cold/Physics

Abstract

We aim to slow a supersonic, molecular beam of $^{11}$BH using a Zeeman slower and subsequently cool the molecules to sub-millikelvin temperatures in a magneto-optical trap. Most molecules are not suitable for direct laser cooling because the presence of rotational and vibrational degrees of freedom means there is no closed-cycle transition which is necessary to scatter a large number of photons. As was pointed out by Di~Rosa\footnote{M.~D.~Di~Rosa, \textit{The European Physical Journal D}~\underline{\textbf{31}}, 395, 2004} there exists a class of molecules for which the excitation of vibrational modes is suppressed due to highly diagonal Franck-Condon factors. Furthermore, Stuhl et al.\footnote{B.~K.~Stuhl et al., \textit{Physical Review Letters}~\underline{\textbf{101}}, 243002, 2008} showed that angular momentum selection rules can be used to suppress leakage to undesired rotational states. Here we present a measurement of the radiative branching ratios of the $A^1\Pi\rightarrow X^1\Sigma$ transition in $^{11}$BH - a necessary step towards subsequent laser cooling experiments. We also perform high-resolution mm-wave spectroscopy of the $J'=1\leftarrow J=0$ rotational transition in the $X^1\Sigma (v=0)$ state near 708~GHz. From this measurement we derive new, accurate hyper fine constants and compare these to theoretical descriptions. The measured branching ratios suggest that it is possible to laser cool $^{11}$BH molecules close to the recoil temperature of 4~$\mu$K using three laser frequencies only.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/50827

DOI

https://doi.org/10.15278/isms.2014.RH04

Copyright and License Information

Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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