Experimental Progress in Laser-Cooling Molecules

At Los Alamos National Laboratory, we are studying a particular class of diatomics -- the alkaline-earth monohydrides ({\em e.g.} BeH and CaH) -- that have Rydberg transitions similar to the $^2$$P_{1/2,\, 3/2} \leftarrow \, ^2$$S_{1/2}$ transitions of alkali atoms and appear suited to laser cooling. As a class, the $A\leftarrow X$ transitions of the alkaline-earth monohydrides possess characteristics that are favorable for Doppler-cooling, including a (nearly) diagonal Franck-Condon array and good spectral isolation of the transitions that form the cooling cycle. We will show how a beam of such molecules can be laser cooled and report the status of our experiments for the particular case of CaH.