Laser Cooling Hits New Low

Robert Pool

Ignacio Enrique Olivares Bahamondes, Patrick Carrazana

Tao Chen, Bo Yan

Different from atoms, molecules have unique properties, and play an important role in the research of atomic, molecular and optical physics. Cold molecules have important applications in science and have been studied for more than 20 years. But traditional methods, such as the Stark decelerator, have hit a bottleneck: it is hard to increase the phase space density of molecules. Extending the direct laser-cooling technique to new molecular species has recently been a hot topic and also a big challenge. In this review paper, on one hand, we make a brief review to recent progresses on the direct laser cooling of polar molecules. On the other hand, a demonstration on the feasibility of laser cooling BaF molecule has been experimentally illustrated, including the analysis on the molecular energy levels, measurements of the high-resolution spectroscopy, efficient pre-cooling and state preparation via buffer-gas cooling and detailed investigations on the molcule-light interactions. All these results not only pave the way for future laser-cooling and -trapping experiments, but also serve as a reference for the laser-cooling explorations on new molecular species.

Pierre Meystre

José Tito Mendonça, Hugo Terças

Alison Goddard

Winning the Nobel prize for physics is like being hit by a tornado, according to one of this year's laureates. "I just wish it would stop so that I could go back to work," says Claude Cohen-Tannoudji of the Collège de France and the Ecole Normale Supérieure in Paris. He shares the 1997 prize with Steve Chu of Stanford University in California and Bill Phillips of the National Institute of Standards and Technology in Gaithersburg, Maryland, for developing techniques to cool and trap atoms at extremely low temperatures using lasers.