Increased atom-cavity coupling through cooling-induced atomic reorganization

The strong coupling of atoms to optical cavities can improve optical lattice clocks as the cavity enables metrologically useful collective atomic entanglement and high-fidelity measurement. To this end, it is necessary to cool the ensemble to suppress motional broadening, and advantageous to maximize and homogenize the atom-cavity coupling. We demonstrate resolved Raman sideband cooling via the cavity as a method that can simultaneously achieve both goals. In 200 ms of Raman sideband cooling, we cool <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mmultiscripts><a:mi mathvariant="normal">Yb</a:mi><a:mprescripts/><a:none/><a:mrow><a:mn>171</a:mn></a:mrow></a:mmultiscripts></a:math> atoms to an average vibration number <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mrow><c:mo>〈</c:mo><c:msub><c:mi>n</c:mi><c:mi>x</c:mi></c:msub><c:mo>〉</c:mo></c:mrow><c:mo>=</c:mo><c:mn>0.23</c:mn><c:mrow><c:mo>(</c:mo><c:mn>7</c:mn><c:mo>)</c:mo></c:mrow></c:mrow></c:math> in the tightly binding direction, resulting in <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mrow><d:mn>93</d:mn><d:mo>%</d:mo></d:mrow></d:math> optical <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mi>π</e:mi></e:math>-pulse fidelity on the clock transition <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mrow><f:mmultiscripts><f:mi>S</f:mi><f:mn>0</f:mn><f:none/><f:mprescripts/><f:none/><f:mn>1</f:mn></f:mmultiscripts><f:mo>→</f:mo><f:mmultiscripts><f:mi>P</f:mi><f:mn>0</f:mn><f:none/><f:mprescripts/><f:none/><f:mn>3</f:mn></f:mmultiscripts></f:mrow></f:math>. During cooling, the atoms self-organize into locations with maximal atom-cavity coupling, which will improve quantum metrology applications. Published by the American Physical Society 2024