1D Laser Cooling of the Asymmetric Top Molecule CaNH₂

Laser cooling of molecules has attracted much attention for recent successes across a variety of experiments in areas such as quantum science and precision measurements. Previously demonstrated molecular laser cooling schemes have tended to rely on the symmetries of select molecules, being limited to linear or symmetric top species. However, most polyatomic molecules are asymmetric top molecules (ATMs), possessing three distinct moments of inertia. The reduced symmetry, though leading to increased complexity in the laser cooling scheme, also offers numerous benefits such as long-lived parity doublets and rich internal structure. Here, we present spectroscopy of the polyatomic ATM calcium amide (CaNH₂) to identify the photon cycling transition and first two vibrational repump transitions. We then report optical cycling of about 30 photons, and ultimately demonstrate 1D Doppler heating and cooling of CaNH₂ as well as signatures of 1D magnetically assisted Sisyphus heating and cooling.