Coherent control of (non-)Hermitian mode coupling: tunable chirality and exceptional point dynamics in photonic microresonators

Bülent Aslan; Riccardo Franchi; Stefano Biasi; Salamat Ali; Davide Olivieri; Lorenzo Pavesi

doi:10.1038/s41377-025-02176-3

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Coherent control of (non-)Hermitian mode coupling: tunable chirality and exceptional point dynamics in photonic microresonators

Original Articles

- Coherent control of (non-)Hermitian mode coupling: tunable chirality and exceptional point dynamics in photonic microresonators
- Light: Science & Applications Vol. 15, Issue 5, Pages: 1665-1678(2026)
- Affiliations：
  
  1.Nanoscience Laboratory, Department of Physics, University of Trento, Povo, Italy
  2.Present address: Nanomaterials & Nanostructure Optics, Department of Electrical and Computer Engineering, Boston University, Boston, MA, USA
- Author bio：
  
  Stefano Biasi (stefano.biasi@unitn.it)
- Funds：
- DOI：10.1038/s41377-025-02176-3
  CLC：
- Received：10 April 2025，
  
  Revised：2025-12-18，
  
  Accepted：21 December 2025，
  
  Online First：06 March 2026，
  
  Published：31 May 2026
- Accepted：
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Aslan, B. et al. Coherent control of (non-)Hermitian mode coupling: tunable chirality and exceptional point dynamics in photonic microresonators. Light: Science & Applications, 15, 1665-1678 (2026).
DOI：

Aslan, B. et al. Coherent control of (non-)Hermitian mode coupling: tunable chirality and exceptional point dynamics in photonic microresonators. Light: Science & Applications, 15, 1665-1678 (2026). DOI： 10.1038/s41377-025-02176-3.

摘要

Abstract

This work introduces a novel on-chip integrated photonic device

the Dynamically Reconfigurable Unified Microresonator (DRUM)

enabling full and dynamic control of Hermitian and non-Hermitian modal coupling between counter-propagating modes in a microresonator. The DRUM consists of a microresonator coupled to two tunable side waveguides

each incorporating a Mach-Zehnder Interferometer and a phase shifter

allowing for independent manipulation of the amplitude and phase of the coupling coefficients. This unique architecture facilitates a continuous and arbitrary transition between diabolic points (DPs) and exceptional points (EPs). We experimentally demonstrate the versatility of the DRUM through several key functionalities: dynamic tuning of the resonance spectral lineshape

coherent suppression of backscattering to achieve an ideal DP

and operation in both Hermitian and non-Hermitian states

enabling continuous chirality tuning and dynamic steering between two EPs. The device achieves a chirality of ±1 at the EPs

indicating strong directionality in light propagation. The experimental results

supported by a theoretical model based on Temporal Coupled Mode Theory

pave the way for reconfigurable photonic devices that exploit (non-)Hermitian dynamics for advanced functionalities

with potential applications ranging from high-sensitivity sensors to neuromorphic computing. The DRUM overcomes the limitations of previous implementations by offering unprecedented control over the coupling between counter-propagating modes within a single integrated device.

关键词

Keywords

references

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