Selecting mode by the complex Berry phase in non-Hermitian waveguide lattices

Area of Science:

• Non-Hermitian physics
• Topological photonics
• Condensed matter theory

Background:

• Bloch oscillations (BOs) are fundamental phenomena in periodic systems.
• Parity-time (PT)-symmetric systems offer unique properties in non-Hermitian physics.
• Su-Schrieffer-Heeger (SSH) models describe topological phases in lattices.

Purpose of the Study:

• Investigate Bloch oscillations in PT-symmetric SSH waveguide arrays.
• Understand the influence of complex Berry phase and topology on BO dynamics.
• Propose an experimental realization and explore potential device applications.

Main Methods:

• Theoretical investigation of BOs in PT-symmetric SSH waveguide arrays.
• Analysis of complex Berry phase and topological properties.
• Numerical simulation using a bent waveguide array model.

Main Results:

• BOs are amplified or damped even with real energy bands.
• Complex Berry phase and topological properties dictate BO amplification/damping.
• Topologically nontrivial lattices show more prominent effects and allow mode selection.
• Numerical simulations confirm theoretical predictions.

Conclusions:

• Topological properties significantly impact bulk Bloch mode dynamics in PT-symmetric SSH systems.
• Complex Berry phase is key to understanding BO amplification and damping.
• Mode selection via complex Berry phase offers potential for integrated photonic devices like mode filters.