Silicon photonic crystal nanocavity-coupled waveguides for error-corrected optical biosensing

Area of Science:

• Photonics
• Nanotechnology
• Biomedical Engineering

Background:

• Optical biosensors are crucial for label-free detection.
• Photonic crystal (PhC) waveguides offer unique optical properties for sensing applications.
• Developing error-corrected sensors is essential for reliable biological measurements.

Purpose of the Study:

• To investigate a photonic crystal waveguide-based optical biosensor for label-free and error-corrected sensing.
• To evaluate the biosensing performance for human IgG detection.
• To explore the potential of PhC devices as ultrasensitive multiplex sensors.

Main Methods:

• Theoretical prediction of optical characteristics using FDTD methods.
• Fabrication of the PhC waveguide and nanocavity structure using nanolithography and reactive-ion-etching.
• Experimental characterization of refractive index sensitivity and human IgG detection.

Main Results:

• The PhC waveguide biosensor demonstrated a refractive index sensitivity of 10^-2 RIU.
• High sensitivity for human IgG detection (2.3±0.24×10^5 nm/M) with a lowest detection limit of 1.5 fg.
• Specific, concentration-dependent responses consistent with Langmuir behavior for IgG detection.

Conclusions:

• The developed PhC devices show significant potential as microscale, label-free, error-correcting sensors.
• The technology may be useful for future ultrasensitive multiplexed biosensing applications.
• This work advances the field of optical biosensing with PhC technology.