Nonlinear Waves and Turbulence in Photonics 2022 - Abstract
Two examples of solitons in non-Hermitian potentials with exceptional points (EPs) are considered. First, in a waveguide with a weakly nonlinear active core and absorbing boundaries, featuring an EP in the linear spectrum of the TM modes, originally focusing (defocusing) material nonlinearity can be transformed into effectively defocusing (focusing) one. This occurs due to the geometric phase of the carried eigenmode when the surface impedance encircles the exceptional point. An EP point can also result in enhancement of the effective nonlinearity. In the second setting, a two-dimensional nonlinear waveguide with distributed gain and losses is considered. Below an EP of the respective non-Hermitian potential, the waveguide sustains two-component envelope solitons. We derive one-dimensional equations for the slowly varying envelopes of the soliton components and show their stable propagation. Within the framework of the original model, the obtained bright solitons are metastable and persist over remarkably long propagation distances.
The reported results are obtained in collaboration with B. Midya, D. A. Zezyulin, and Y. V. Kartashov.