Multimode Sensing by Optical Whispering-gallery-mode Barcodes: A New Route to Expand Dynamic Range for...

Area of Science:

• Optical sensing
• Microresonator technology
• Biochemical and physical parameter detection

Background:

• Whispering-Gallery-Mode (WGM) microresonators offer high sensitivity, resolution, and small size for optical sensing.
• Conventional single-mode sensing techniques are limited by a narrow dynamic range.

Purpose of the Study:

• To develop a theoretical framework for multimode sensing techniques.
• To introduce an optical WGM barcode technique for simultaneous monitoring of multiple modes.
• To assess theoretical limits of measurement resolution and dynamic range.

Main Methods:

• Development of a theoretical framework for multimode sensing.
• Demonstration of an optical WGM barcode technique.
• Analysis of Cramer-Rao bounds (CRB) for resonance shift estimation.

Main Results:

• The WGM barcode technique enables over-Free Spectral Range (FSR) tracking with high resolution.
• Multimode sensing significantly improves resolution and dynamic range compared to single-mode sensing.
• CRB analysis provides theoretical limits for measurement resolution and dynamic range.

Conclusions:

• The WGM barcode technique offers a pathway to high-resolution sensors with expanded dynamic range.
• This approach enhances sensitivity and measurement capabilities in optical sensing.
• The theoretical framework provides insights into optimizing sensor performance.