One-Dimensional Laser-cooling of Asymmetric Top Molecules

The rich internal structure of molecules provides various features that makes them powerful new probes for beyond the Standard Model physics as well as a versatile platform for quantum information processing. Over the past decade, progress has been made in bringing new classes of molecules of increasing complexity to the ultracold regime, with the expansion of the laser-cooling toolkit to diatomic species (AlF, BaF, CaF, CaH, SrF, YO, YbF), linear triatomic molecules (CaOH, SrOH), and larger symmetric top molecules (CaOCH₃). We report one-dimensional laser cooling of an asymmetric top molecule (ATM), CaNH₂. We describe our progress towards cycling many thousands of photons with this molecule, which would allow for deep laser cooling into the microkelvin temperature regime. Our work lays the foundation for trapping of ultracold CaNH₂, and, more broadly, the class of ATMs.