Laser Cooling of CaH Molecules

We present experimental results that lead to the transverse laser cooling of a cryogenic beam of CaH molecules via the Doppler and Sisyphus mechanisms. We investigate the relevant molecular structure through in-cell absorption spectroscopy and high resolution in-beam spectroscopy, and discuss the experimental apparatus necessary to effectively cool CaH. We compare and contrast the requirements and obstacles arising from cooling on the ΧΣ-ΒΣ transition versus the ΧΣ-AΠ transition. We also compare the experimentally measured vibrational branching ratios (f00, f01,f02) of the two cooling states to their theoretically predicted values and discuss how to close vibrational loss channels in the cycling scheme. Finally, we discuss laser cooling of CaH molecules as we progress towards a MOT, and, in the future, dissociation of CaH and creation of a trapped ultracold gas of hydrogen atoms.