title: PT symmetry with a system of three-level atoms.
abstract: We show that a vapor of multilevel atoms driven by far-off-resonant laser beams, with the possibility of interference of two Raman resonances, is highly efficient for creating parity-time symmetric profiles of the probe-field refractive index, whose real part is symmetric and imaginary part is antisymmetric in space. The spatial modulation of the probe-field susceptibility is achieved by a proper combination of standing-wave strong control fields and of Stark shifts induced by far-off-resonance laser fields. As particular examples we explore a mixture of isotopes of rubidium atoms and design a parity-time symmetric lattice and a parabolic refractive index with a linear imaginary part.
authors.affiliation: State Key Laboratory of Precision Spectroscopy and Department of Physics, East China Normal University, Shanghai 200062, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Hang
authors.forename: Guoxiang
authors.initials: G
authors.lastname: Huang
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Konotop