Production and Detection of Ultracold Ground State 85Rb133Cs Molecules in the Lowest Vibrational Level by Short-Range Photoassociation**Supported by the National Basic Research Program of China under Grant No 2012CB921603, the National Natural Science Foundation of China under Grant Nos 61275209, 11304189, 61378015 and 11434007, the National Natural Science Foundation for Excellent Research Team under Grant No 61121064, and the Program

Abstract

We investigate the production of ultracold ground state X1σ+ (v = 0) RbCs molecules in the lowest vibrational level via short-range photoassociation followed by spontaneous emission. The starting point is the laser cooled 85Rb and 133Cs atoms in a dual species, forced dark magneto-optical trap. The special intermediate level (5)0+(v = 10) correlated to the (2)3π electric state is achieved by the photoassociation process. The formed ground state X1σ+ (v = 0) molecule is resonantly excited to the 21π intermediate state by a 651 nm pulse laser and is ionized by a 532 nm pulse laser and then detected by the time-of-flight mass spectrum. Saturation of the photoionization spectroscopy at large ionization laser energy is observed and the ionization efficiency is obtained from the fitting. The production of ultracold ground state 85Rb133Cs molecules is facilitative for the further research about the manipulation of ultracold molecules in the rovibrational ground state.