New methods for enhanced production of laser-coolable molecules

Radical polyatomic molecules can be produced from gas-phase atomic metal precursors in the presence of a reagent gas. Previous work with YbOH [1] and CaOH [2] has shown that molecular production in a cryogenic buffer-gas cell can be enhanced more than ten-fold by populating metastable triplet electronic states of metal atom precursors. These demonstrations, while highly effective, required excitation of weak intercombination (i.e., spin-flip) transitions. Here we report work exploring alternative pathways to populate these metastable states via two-step excitation on strong transitions followed by spontaneous decay to the target states. Candidate pathways have been identified for calcium- and strontium-containing molecules. We present our results measuring enhancement factors for production of several molecules used in ongoing molecular physics experiments.

[1] Jadbabaie et al., New J. Phys. 22, 022002 (2020); [2] Zhang et al., J. Chem. Phys. 155, 091101 (2021)