title: Enhanced cross-phase modulation based on a double electromagnetically induced transparency in a four-level tripod atomic system.
abstract: We report experimental observations on the simultaneous electromagnetically induced transparency (EIT) effects for probe and trigger fields (double EIT) as well as the enhanced cross-phase modulation (XPM) between the two fields in a four-level tripod EIT system of the D1 line of 87Rb atoms. The XPM coefficients (larger than 2 x 10(-5) cm2/W) and the accompanying transmissions (higher than 60%) are measured at a slight detuning of the probe field from the exact EIT-resonance condition. The system and enhanced cross-Kerr nonlinearities presented here can be applied to quantum information processes.
authors.affiliation: The State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, People's Republic of China.
authors.forename: Shujing
authors.initials: S
authors.lastname: Li
authors.forename: Xudong
authors.initials: X
authors.lastname: Yang
authors.forename: Xuemin
authors.initials: X
authors.lastname: Cao
authors.forename: Chunhong
authors.initials: C
authors.lastname: Zhang
authors.forename: Changde
authors.initials: C
authors.lastname: Xie
authors.forename: Hai
authors.initials: H
authors.lastname: Wang