Compact dual-band MIM plasmonic sensor with enhanced sensitivity for biochemical sensing.

Area of Science:

• Photonics and Nanotechnology
• Plasmonics
• Sensor Technology

Background:

• Refractive index (RI) sensors are crucial for detecting chemical and biological analytes.
• Plasmonic sensors offer high sensitivity due to their interaction with light at the nanoscale.
• Metal-insulator-metal (MIM) waveguide structures are promising for sensor applications.

Purpose of the Study:

• To investigate a novel dual-band plasmonic RI sensor.
• To achieve high sensitivity and figure of merit for analyte detection.
• To explore the sensor's performance in detecting lead nitrate and thyroxine.

Main Methods:

• Designing a dual-band plasmonic RI sensor using an air-silver MIM waveguide with a circular cavity and elliptical notch.
• Modeling and optimizing the sensor design using COMSOL Multiphysics and a 2D finite element method.
• Analyzing the sensor's dual-band resonance behavior and performance metrics.

Main Results:

• The proposed sensor exhibits dual-band resonance in the 800-1200 nm and 1300-1900 nm ranges.
• Achieved high sensitivities: 1137-1970 nm/RIU for lead nitrate and 682-1136.4 nm/RIU for thyroxine.
• Demonstrated a high figure of merit (FoM) of 76, a Q-factor of ~83, max transmission of ~88%, and narrow FWHM of 24.8 nm.

Conclusions:

• The novel dual-band plasmonic RI sensor shows significant potential for high-resolution detection.
• The sensor's design and performance metrics are suitable for sensitive and selective analyte sensing.
• This work contributes to the advancement of plasmonic sensor technology for various applications.