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Non-Hermitian interband coupling manipulation: from unidirectional reflectionless to unilateral perfect absorption.
Optics Letters
|January 30, 2026
Summary
This study introduces a new topology-supported design for unilateral perfect absorption (UPA) in optical systems. It enables controlled asymmetric absorption at exceptional points (EPs) by manipulating mode radiation direction.
Area of Science:
- Photonics and optical systems
- Non-Hermitian physics
- Condensed matter theory
Background:
- Unilateral perfect absorption (UPA) is crucial for optical applications and extends unidirectional reflectionlessness (UR).
- Existing UR-based UPA designs lack systematic frameworks, complicating parameter adjustments.
- Exceptional points (EPs) in non-Hermitian systems are key to UR and UPA phenomena.
Purpose of the Study:
- To develop a systematic design framework for achieving UPA at EPs.
- To enable controlled asymmetric absorption in optical continuum systems.
- To provide new insights into asymmetric optical field manipulation.
Main Methods:
- Utilizing a quasi-normal-mode perspective.
- Introducing a topology-supported design scheme.
- Converting inter-resonator/array coupling to interband coupling.
- Analyzing mode radiation direction and asymmetry.
Main Results:
- Successfully predicted and realized UPA at an EP in continuum optical systems.
- Demonstrated controlled asymmetric absorption via manipulated mode radiation.
- Identified maximum absorption asymmetry under extreme radiation asymmetry (unidirectional guided resonance).
Conclusions:
- The proposed framework offers a systematic approach to UPA design at EPs.
- The method facilitates precise control over asymmetric optical absorption.
- This work advances optical field manipulation and photonic device design.
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