As a preliminary towards our plans to study heat transport in nanoscale systems using trapped ion chains as a 1D model, we need to measure the isotope shift in the Ca+ 729 nm electric quadrupole transition. It turns out that this type of measurement also has applications to probing beyond-Standard-Model physics by looking for non-linearities in King plots of the isotope shifts on two transitions in the same system – see for example PRL 120, 091801 (2018).
In any case, we’ve just taken our first super-preliminary isotope shift data. Here we are co-trapping 40Ca+ and 40Ca+ and driving them simultaneously with two frequency sidebands applied to our 729 nm laser with an EOM:
