New Molecular Species for Quantum Science and Precision Measurements

Following recent advances in the quantum control of molecules, it now appears feasible to laser cool species of increasingly low symmetry. While this entails some additional experimental challenges, it also introduces new physical features and structural complexity that can be exploited for improved control of molecular interactions or sensitivity of precision measurements. For example, many laser-coolable asymmetric top molecules have large dipole moments (>5 Debye) for improved molecule-molecule coupling, permanent dipole moments along orthogonal axes, and vast rovibrational structures for information storage. For precision measurements, the numerous rovibrational modes in larger molecules, such as torsional modes, show promise for enhanced sensitivity to measurements of fundamental constant variation. We present measurements of vibrational branching ratios for asymmetric molecules CaSH and CaNH₂, showing a favorable pathway for laser cooling. We also present studies of laser-coolable organic molecules, such as benzene or cresol, decorated with CaO optical cycling centers.