An Analysis of a Compact Label-Free Guiding-Wave Biosensor Based on a Semiconductor-Clad Dielectric Strip Waveguide

Area of Science:

• Photonics and Biosensing
• Integrated Optics
• Biomedical Engineering

Background:

• Development of compact, label-free biosensors is crucial for point-of-care diagnostics.
• Existing photonic biosensors often require larger footprints, limiting miniaturization.
• CMOS-compatible materials offer a pathway for scalable and cost-effective biosensor fabrication.

Discussion:

• A novel semiconductor-clad strip waveguide biosensor is proposed, utilizing amorphous silicon and silicon oxynitride.
• The device's optical performance was modeled using a 3D beam propagation method.
• Fabrication tolerances were analyzed to assess practical implementation feasibility.

Key Insights:

• The 20-μm-long device demonstrates a surface limit of detection of 3 ng/cm² for avidin.
• Achieved sensitivity is comparable to larger photonic biosensors.
• The compact design offers significant advantages in terms of size and potential integration.

Outlook:

• Further optimization of materials and design could enhance sensitivity and specificity.
• Integration with microfluidics could enable complex biological assays.
• Potential for widespread adoption in diagnostics and research due to its compact and efficient design.