YbH+ formation in an ytterbium ion trap

The trapped Yb-171(+) ion is a promising candidate for portable atomic clock applications. However, with buffer-gas cooled ytterbium ions, the ions can be pumped into a low-lying F-2(7/2) state or form YbH+ molecules. These dark states reduce the fluorescence signal from the ions and can degrade the clock stability. In this work, we study the dynamics of the populations of the F-2(7/2) state and YbH+ molecules under different operating conditions of our Yb-171(+) ion system. Our study indicates that F-2(7/2)-state ions can form YbH+ molecules through interactions with hydrogen gas. As observed previously, dissociation of YbH+ is observed at wavelengths around 369 nm. We also demonstrate YbH+ dissociation using 405 nm light. Moreover, we show that the population in the dark states can be limited by using a single repump laser at 935 nm. Our study provides insights into the molecular formation in a trapped ion system.