Stationary Light Pulses in Cold Atomic Media
  Stationary light pulses (SLPs), i.e., light pulses without motion, are formed via the retrieval of stored probe pulses with two counter-propagating coupling fields. We show that there exist non-negligible hybrid Raman excitations in media of cold atoms that prohibit the SLP formation. We experimentally demonstrate a method to suppress these Raman excitations and realize SLPs in laser-cooled atoms. Our work opens the way to SLP studies in cold as well as in stationary atoms and provides a new avenue to low-light-level nonlinear optics. 
Wen-Te Liao, Yen-Wei Lin, Thorsten Peters, Hung-Chih Chou, Jian-Siung   Wang, Pei-Chen Kuan, and Ite A. Yu