Autler-Townes splitting biosensing based on a nonuniform photonic crystal waveguide with feedback loop

Area of Science:

• Photonics
• Biosensing
• Optical Engineering

Background:

• High-performance biosensors are crucial for rapid and accurate detection of biological molecules.
• Existing biosensing technologies face limitations in sensitivity and noise immunity.
• Photonic crystal waveguides offer potential for advanced optical sensing applications.

Purpose of the Study:

• To investigate a novel nonuniform photonic crystal waveguide (NUPhCW) with a feedback loop for high-performance biosensing.
• To leverage the mode-splitting effect for sensitive detection of refractive index changes.
• To develop a self-referencing detection mechanism for enhanced noise immunity.

Main Methods:

• Systematic investigation of a NUPhCW with a feedback loop.
• Utilizing the Autler-Townes splitting effect induced by nonuniform hole design.
• Analyzing the change in resonance mode spacing with environmental refractive index variations.

Main Results:

• The NUPhCW exhibits Autler-Townes splitting due to its carefully designed nonuniform holes and feedback loop.
• The spacing between the two splitting resonance modes is sensitive to changes in the environmental refractive index.
• Achieved a sensitivity of approximately 117 nm/RIU, which is 2.6 times higher than common microring resonators.
• Demonstrated self-referencing detection capability for immunity against environmental noise.

Conclusions:

• The proposed NUPhCW with a feedback loop is a promising platform for high-quality, label-free biosensing.
• The device offers significantly enhanced sensitivity compared to conventional microring resonators.
• The integrated self-referencing capability makes it robust against environmental noise, improving detection reliability.