Silicon-tapered waveguide for mode conversion in metal-insulator-metal waveguide-based plasmonic sensor for...

Area of Science:

• Photonics and Nanotechnology
• Plasmonics
• Optical Sensing

Background:

• Metal-insulator-metal (MIM) plasmonic waveguides offer unique light confinement properties.
• Refractive index sensors are crucial for various applications, including chemical and biological detection.
• Efficient light coupling and mode transformation are key challenges in nanoscale plasmonic devices.

Purpose of the Study:

• To numerically investigate a novel refractive index sensor based on a modified MIM plasmonic waveguide.
• To enhance light coupling efficiency and improve the extinction ratio of the sensor.
• To analyze the light injection mechanism into nanoscale MIM waveguides using silicon tapers.

Main Methods:

• Finite element method (FEM) for comprehensive numerical analysis.
• Design and simulation of a modified ring resonator coupled to a bus waveguide.
• Incorporation of silicon-tapered waveguides for dielectric-to-plasmonic mode conversion.

Main Results:

• Achieved a high sensitivity of approximately 1155.71 nm/RIU.
• Obtained a figure of merit (FOM) of 25.9.
• Demonstrated enhanced light coupling and improved extinction ratio due to resonator modification.
• Validated the effectiveness of silicon tapers for mode transformation.

Conclusions:

• The modified MIM plasmonic waveguide sensor shows significant potential for high-performance refractive index sensing.
• The study provides insights into optimizing light coupling and mode conversion in plasmonic waveguides.
• Findings pave the way for practical realization of efficient and precise plasmonic sensing systems.