Geometry-dependent skin effects in reciprocal photonic crystals

Area of Science:

• Condensed Matter Physics
• Photonics
• Topological Physics

Background:

• The skin effect, where eigenmodes localize to the edges of a material, is typically observed in non-Hermitian systems.
• Existing realizations are often limited to one-dimensional or nonreciprocal systems.
• Understanding the role of complex eigenvalues and topological properties is crucial for controlling the skin effect.

Purpose of the Study:

• To propose a realistic, reciprocal two-dimensional (2D) photonic crystal (PhC) system exhibiting the skin effect.
• To establish a design strategy for non-Hermitian systems based on exceptional points (EPs) and eigenvalue topology.
• To demonstrate the existence of the skin effect in the designed 2D PhC.

Main Methods:

• Theoretical design of a reciprocal 2D PhC based on model Hamiltonian theory.
• Analysis of the connection between order-2 exceptional points (EPs) and skin effects through eigenvalue topology.
• Projected-band-structure calculations and time-domain simulations to verify the skin effect at crystalline interfaces.

Main Results:

• A novel routine for designing non-Hermitian systems with skin effects is established.
• A 2D PhC with exceptional points (EPs) and nonzero eigenvalue winding numbers is successfully designed.
• Projected-band-structure and time-domain simulations confirm the presence of the skin effect at interfaces.

Conclusions:

• The proposed reciprocal 2D PhC system offers a practical platform for realizing the skin effect.
• The established design strategy provides a pathway for creating novel non-Hermitian photonic systems.
• These findings lay the groundwork for experimental verification and future applications of the skin effect in photonics.