Chiral transmission by an open evolution trajectory in a non-Hermitian system

Area of Science:

• Non-Hermitian physics
• Quantum mechanics
• Photonics

Background:

• Exceptional points (EPs) are singularities in non-Hermitian systems where eigenvalues and eigenstates merge.
• Dynamic encircling of EPs can induce chiral transmission, a phenomenon where the system's final state depends on the encircling direction.
• Previous methods for chiral transmission, often using parity-time (PT)-symmetric systems, suffered from low efficiency due to path-dependent losses.

Purpose of the Study:

• To demonstrate a new method for achieving high-efficiency chiral transmission.
• To explore chiral dynamics without requiring closed trajectories around exceptional points.
• To lay the foundation for practical chiral transmission devices.

Main Methods:

• Investigated chiral dynamics in a coupled waveguide system using an open trajectory.
• Explored an open trajectory linking two infinite points with identical asymptotic eigenmodes.
• Experimentally implemented the concept in a coupled silicon waveguide system operating at telecommunication wavelengths.

Main Results:

• Achieved high-efficiency chiral transmission without needing a closed trajectory.
• Demonstrated that each eigenmode can be localized in a single waveguide.
• Showcased a novel platform for chiral dynamics with superior performance compared to previous methods.

Conclusions:

• The developed open trajectory strategy enables efficient chiral transmission, overcoming limitations of previous approaches.
• This work provides a new paradigm for manipulating chiral dynamics in resonant systems.
• The findings pave the way for the development of practical devices utilizing chiral transmission.