Efficient field-free orientation of CO molecules using a three-step excitation schemeYin Huang, Ting Xie, Gao-Ren Wang, Yong-Chang Han and Shu-Lin CongEur. Phys. J. D, 67 11 (2013) 227DOI: https://doi.org/10.1140/epjd/e2013-40383-y