Hybrid Metasurface Based Tunable Near-Perfect Absorber and Plasmonic Sensor

Area of Science:

• Metasurface optics
• Plasmonics
• Nanophotonics

Background:

• Metasurfaces offer unique light-matter interaction properties.
• Perfect absorbers are crucial for various photonic applications.
• Plasmonic sensors require high sensitivity and selectivity.

Purpose of the Study:

• To propose and numerically investigate a hybrid metasurface-based perfect absorber.
• To demonstrate its capability as a refractive index sensor.
• To explore its potential in solar energy and biochemical detection.

Main Methods:

• Utilizing a gold mirror to eliminate transmission.
• Employing amorphous silicon (a-Si) nanodisk arrays for surface plasmon excitation.
• Numerical investigation of optical properties and sensing performance.

Main Results:

• Achieved near-unity absorbance (99.8%) at 932 nm in air.
• Demonstrated polarization-independent absorption.
• Maintained high absorbance (>99.7%) for refractive indices from 1.33 to 1.41.
• Exhibited an average sensitivity of 325 nm/RIU and maximum of 350 nm/RIU.

Conclusions:

• The proposed hybrid metasurface acts as an efficient perfect absorber and a sensitive refractive index sensor.
• Its impedance matching enables near-unity absorbance and zero-reflectance.
• Potential applications include solar cells, photodetectors, and biochemical sensing.