Enabling infinite Q factors in absorbing optical systems

Area of Science:

• Optics and Photonics
• Materials Science
• Condensed Matter Physics

Background:

• Resonant optical structures are crucial in various scientific and technological applications.
• Optical absorption in structural components significantly degrades the quality (Q) factors of these resonances.
• Existing methods struggle to maintain high Q factors in the presence of optical absorption.

Purpose of the Study:

• To demonstrate a novel mechanism for creating absorption-free bound states in the continuum (BICs).
• To engineer ultrahigh-Q resonant optical structures despite inherent optical absorption.
• To achieve theoretically unlimited Q factors in BICs interacting with lossy materials.

Main Methods:

• Coupling a lossy mode of an optical structure to two independent lossless modes.
• Theoretical analysis of bound states in the continuum (BIC) formation.
• Design and simulation of a plasmonic metasurface exhibiting the proposed BIC mechanism.

Main Results:

• Successfully created a nonradiating and absorption-free bound state in the continuum (BIC).
• Achieved theoretically unlimited Q factors for the engineered BIC, even with optical absorption.
• Designed a plasmonic metasurface with Q factors approaching 10^7 in the visible spectrum.

Conclusions:

• The presented mechanism effectively overcomes limitations imposed by optical absorption in resonant structures.
• This approach enables the engineering of ultrahigh-Q resonances in diverse systems containing absorbing materials.
• The findings pave the way for advanced optical devices with unprecedented performance characteristics.