Formation of ultracold polar molecules in the rovibrational ground state

Ultracold LiCs molecules in the absolute ground state X-1 Sigma(+), nu '' = 0, J '' = 0 are formed via a single photoassociation step starting from laser-cooled atoms. The selective production of nu '' = 0, J '' = 2 molecules with a 50-fold higher rate is also demonstrated. The rotational and vibrational state of the ground state molecules is determined in a setup combining depletion spectroscopy with resonant-enhanced multiphoton ionization time-of-flight spectroscopy. Using the determined production rate of up to 5 x 10(3) molecules/s, we describe a simple scheme which can provide large samples of externally and internally cold dipolar molecules.