Tunable Split-Disk Metamaterial Absorber for Sensing Application

Area of Science:

• Metamaterials
• Nanophotonics
• Optical Sensing

Background:

• Metamaterials offer unique light-matter interactions.
• Tunable absorbers are crucial for sensing applications.
• Split-disk metamaterials (SDMs) provide a platform for tailored optical responses.

Purpose of the Study:

• To design and investigate four tunable split-disk metamaterial (SDM) absorbers.
• To explore the tunability of absorption resonances and their sensitivity.
• To assess the potential of SDMs for high-sensitivity optical sensing.

Main Methods:

• Fabrication of SDMs with varying split numbers (1 to 4) on a gold mirror and silicon substrate.
• Characterization of absorption spectra and resonance tuning by adjusting geometrical configurations.
• Evaluation of device sensitivity using refractive index unit (RIU) measurements.

Main Results:

• Four SDM designs (SDM-1 to SDM-4) exhibited tunable absorption resonances from 1.5 µm to 5.0 µm.
• Resonances were tunable over a 320 nm range, with intensity decreasing as air insulator gap increased.
• High sensitivities were achieved: 3312 nm/RIU (SDM-1), 3362 nm/RIU (SDM-2), 3342 nm/RIU (SDM-3), and 3567 nm/RIU (SDM-4), with a correlation coefficient of 0.99999.

Conclusions:

• The designed SDMs offer tunable absorption properties for optical sensing.
• The proposed metamaterial absorbers demonstrate high sensitivity, suitable for advanced sensing.
• This work enables the development of highly sensitive optical gas and biosensors.