PT-symmetry with a system of three-level atoms

TL;DR

This paper demonstrates how a vapor of multilevel atoms driven by laser fields can create PT-symmetric optical profiles with controllable real and imaginary parts of the refractive index, enabling advanced optical lattice designs.

Contribution

It introduces a method to generate PT-symmetric refractive index profiles using multilevel atomic vapors with laser-induced interference effects.

Findings

Successful design of PT-symmetric lattice using Rubidium isotopes

Achieved spatial modulation of susceptibility with standing waves and Stark shifts

Demonstrated control over real and imaginary parts of the refractive index

Abstract

We show that a vapor of multilevel atoms driven by far-off resonant laser beams, with possibility of interference of two Raman resonances, is highly efficient for creating parity-time (PT) symmetric profiles of the probe-field refractive index, whose real part is symmetric and imaginary part is anti-symmetric in space. The spatial modulation of the susceptibility is achieved by proper combination of standing-wave strong control fields and of Stark shifts induced by a far-off-resonance laser field. As particular examples we explore a mixture of isotopes of Rubidium atoms and design a PT-symmetric lattice and a parabolic refractive index with a linear imaginary part.