The PT Symmeter » Chao Hang

PT-symmetric coupler with a coupling defect: soliton interaction with exceptional point

dwh — Fri, 09 May 2014 14:16:55 +0000

Yuli V. Bludov, Chao Hang, Guoxiang Huang, Vladimir V. Konotop

We study interaction of a soliton in a parity-time (PT) symmetric coupler which has local perturbation of the coupling constant. Such a defect does not change the PT-symmetry of the system, but locally can achieve the exceptional point. We found that the symmetric solitons after interaction with the defect either transform into breathers or blow up. The dynamics of anti-symmetric solitons is more complex, showing domains of successive broadening of the beam and of the beam splitting in two outwards propagating solitons, in addition to the single breather generation and blow up. All the effects are preserved when the coupling strength in the center of the defect deviates from the exceptional point. If the coupling is strong enough the only observable outcome of the soliton-defect interaction is the generation of the breather.

http://arxiv.org/abs/1405.1829
Optics (physics.optics)

Tunable nonlinear PT-symmetric defect modes with an atomic cell

dwh — Sun, 22 Sep 2013 14:26:56 +0000

Chao Hang, Dmitry A. Zezyulin, Vladimir V. Konotop, Guoxiang Huang

We propose a scheme of creating a tunable highly nonlinear defect in a one-dimensional photonic crystal. The defect consists of an atomic cell filled in with two isotopes of three-level atoms. The probe-field refractive index of the defect can be made parity-time (PT) symmetric, which is achieved by proper combination of a control field and of Stark shifts induced by a far-off-resonance field. In the PT-symmetric system families of stable nonlinear defect modes can be formed by the probe field.

http://arxiv.org/abs/1309.2839

Optics (physics.optics); Pattern Formation and Solitons (nlin.PS)

PT-symmetry with a system of three-level atoms

dwh — Wed, 26 Dec 2012 09:29:11 +0000

Chao Hang, Guoxiang Huang, Vladimir V. Konotop

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.

http://arxiv.org/abs/1212.5486

Optics (physics.optics)