New Mechanism for Generating Quasi-Bound States in Optical Microcavities

Researchers have identified a mechanism for generating quasi-bound states in the continuum (quasi-BIC) within a single deformed microcavity, as detailed in the paper titled "Formation of Quasi-Bound States in the Continuum in a Single Deformed Microcavity" by Shuai Liu, Bo-Han Wu, Jeffrey Huang, and Zheshen Zhang. This study, submitted on August 30, 2024, explores the behavior of bound states in the continuum (BIC), which are significant for manipulating electromagnetic fields and reducing losses in optical structures.

The authors propose that by introducing boundary deformations to the microcavity, stable unidirectional radiation channels can be created. These channels facilitate the coupling of different resonant modes, leading to a significant reduction in the leaking loss of a long-lived resonance. Specifically, the quality (Q) factor of this resonance is enhanced by more than three times, while a short-lived resonance experiences increased loss. This phenomenon demonstrates the formation of Friedrich-Wintgen quasi-BICs, supported by both theoretical models and experimental data.

The implications of this research are notable, as it provides a practical approach to enhance the Q factor of optical microcavities. Such advancements could have applications in various fields, including nonlinear optics, quantum optics, and integrated photonics. The findings contribute to a deeper understanding of optical microcavities, which are essential components in photonic integrated circuits, and may lead to improved performance in optical devices.