Photon Cycling and Laser Cooling of an Asymmetric Top Molecule

Abstract

We realize two-dimensional magnetically-assisted Sisyphus laser cooling of an asymmetric top molecule (ATM), calcium monoamide (CaNH$_2$). Vibrational state closure is achieved with $41.1 \pm 6.3$ photons scatters using optical pumping of the $X[3_1]$ state. Photon-cycling measurements show good agreement with branching ratios determined by dispersed fluorescence spectroscopy. Rotational closure is maintained by driving the $X[1_{11}] \to A [0_{00}]$ transition. The observed absence of additional state leakage channels broadens the scope of molecular laser cooling to include ATMs, which are the most general geometric class of molecules and possess the richest internal structure. Future applications of quantum controlled ATMs include new quantum information platforms and searches for physics beyond the Standard Model.