@article{2566, author = {D. Wang and B. Neyenhuis and M. de Miranda and K.-K. Ni and S. Ospelkaus and Deborah Jin and Jun Ye}, title = {Direct absorption imaging of ultracold polar molecules}, abstract = {We demonstrate a scheme for direct absorption imaging of an ultracold ground-state polar molecular gas near quantum degeneracy. Imaging molecules without closed optical cycling transitions is challenging. Our technique relies on photon-shot-noise-limited absorption imaging on a strong but open bound-bound molecular transition. We present a systematic characterization of this imaging technique. Using this technique combined with time-of-flight expansion, we demonstrate the capability to determine momentum and spatial distributions for the molecular gas. With its capability of imaging molecules in arbitrary external fields, we anticipate that this technique will find many applications in the study of molecular quantum gases.}, year = {2010}, journal = {Physical Review A}, volume = {81}, month = {2010-06}, issn = {1050-2947}, doi = {10.1103/PhysRevA.81.061404}, }