In the ever-evolving landscape of photonics, a groundbreaking study has emerged from the School of Integrated Circuits at Harbin Institute of Technology (Shenzhen), China. Led by Jin Li, this research delves into the intriguing world of higher-order chiral exceptional points (EPs) in asymmetric photonic molecules, promising to revolutionize the energy sector and beyond.
Exceptional points are unique phenomena in open systems, where multiple eigenvalues and their corresponding eigenvectors converge. While second-order EPs have been extensively explored, higher-order EPs remain a largely untapped frontier. Li’s research, published recently, proposes a novel approach to realize these higher-order EPs using an asymmetric photonic molecule (PM).
Traditional photonic molecules consist of identical microresonators. However, Li’s team introduces a spiral-shaped microresonator, creating an asymmetric PM. This innovation enables unidirectional coupling between eigenmodes, transferring chirality throughout the entire PM. “The incorporation of a spiral-shaped microresonator is a game-changer,” Li explains. “It allows us to achieve hierarchical construction of higher-order EPs in both gain–loss asymmetric and all-passive PMs.”
The implications of this research are vast, particularly for the energy sector. Higher-order EPs exhibit superior sensitivity to external perturbations, a trait that can be harnessed for enhanced sensing technologies. This could lead to more efficient energy monitoring and management systems, reducing waste and improving sustainability.
Moreover, the asymmetric PM proposed by Li’s team circumvents the need for external components or precise control of gain–loss profiles. This simplification could pave the way for more robust and cost-effective integrated photonic devices, accelerating the development of next-generation energy technologies.
The prototype demonstration, based on numerical simulations, revealed a fourth-order EP with a three-fold enhancement in sensitivity compared to a second-order EP. This significant improvement underscores the potential of higher-order EPs in practical applications.
As we look to the future, Li’s research opens up new avenues for exploration. The ability to construct higher-order EPs in integrated photonic devices could enable applications in both linear and nonlinear regimes, pushing the boundaries of what’s possible in photonics.
The study, published in the American Physical Society’s journal APL Photonics, translates to American Journal of Photonics, marks a significant step forward in the field. It challenges conventional wisdom and invites further investigation into the fascinating world of higher-order EPs. As Li puts it, “We are just scratching the surface of what’s possible. The future of photonics is bright, and higher-order EPs are set to play a pivotal role.”
The energy sector, in particular, stands to benefit greatly from these advancements. With enhanced sensing technologies and more efficient integrated photonic devices, we can look forward to a future where energy is managed more sustainably and effectively. The journey is just beginning, but the destination promises to be transformative.