Hybrid plasmonic slot waveguide with a metallic grating for on-chip biosensing applications

Area of Science:

• Photonics
• Nanotechnology
• Biomedical Engineering

Background:

• Integrated biosensors are vital for lab-on-a-chip systems.
• High sensitivity and compact design are key challenges in biosensor development.

Purpose of the Study:

• To design and investigate a novel bandpass optical filter as a label-free biosensor.
• To enhance sensitivity and modal overlap with the sensing region in integrated biosensors.

Main Methods:

• Utilized a hybrid slot waveguide on a silicon-on-insulator platform.
• Incorporated a metallic Bragg grating with a phase-shifted cavity.
• Employed 3D finite-difference time-domain (FDTD) simulations to analyze geometrical parameters.

Main Results:

• Achieved a high sensitivity of 270 nm/RIU (refractive index unit).
• Demonstrated a compact footprint of 1.03µm × 17.6µm.
• The design effectively pulls the optical field into the sensing gap, increasing modal overlap.

Conclusions:

• The proposed hybrid slot waveguide biosensor is suitable for sensitive, label-free detection.
• This compact optical filter design advances lab-on-a-chip sensing capabilities.
• The design offers a promising platform for integrated photonic biosensing applications.