Efficient field-free orientation of CO molecules using a three-step excitation scheme Yin Huang, Ting Xie, Gao-Ren Wang, Yong-Chang Han and Shu-Lin Cong Eur. Phys. J. D, 67 11 (2013) 227 Published online: 01 November 2013 DOI: 10.1140/epjd/e2013-40383-y