Integrated optical frequency-resolved Mach-Zehnder interferometers for label-free affinity sensing.

Area of Science:

• Photonics and Sensor Technology
• Integrated Optics
• Biomedical Sensing

Background:

• Label-free affinity sensors are crucial for real-time biomolecular detection.
• Existing Mach-Zehnder Interferometer (MZI) sensors face limitations in sensitivity and versatility.
• Integrated optical devices offer miniaturization and cost-efficiency potential.

Purpose of the Study:

• To introduce Integrated Optical Frequency-Resolved Mach-Zehnder Interferometry (IO FR-MZI) as a novel sensing principle.
• To theoretically analyze and quantify the performance of IO FR-MZI sensors.
• To demonstrate the potential for high sensitivity and versatility in label-free affinity sensing.

Main Methods:

• Detailed theoretical analysis of the IO FR-MZI principle.
• Semi-analytical approximation and numerical calculations for performance evaluation.
• Comparison of IO FR-MZI sensitivity and limit of detection against Single Wavelength MZI.

Main Results:

• IO FR-MZI demonstrates superior sensitivity compared to Single Wavelength MZI.
• An optimized IO FR-MZI sensor (sub-millimeter length) achieved a limit of detection as low as 0.025Å effective thickness.
• The technology is suitable for miniaturized, high-yield fabrication using standard microfabrication techniques.

Conclusions:

• IO FR-MZI is a cost-efficient, highly sensitive, and versatile platform for integrated optical label-free affinity sensors.
• The developed sensor technology enables truly miniaturized devices with broad application potential.
• IO FR-MZI represents a significant advancement in integrated optical sensing technology.