High Sensitive Biosensors Based on the Coupling Between Surface Plasmon Polaritons on Titanium Nitride and a Planar...

Area of Science:

• Optoelectronics
• Nanotechnology
• Biomedical Engineering

Background:

• Surface plasmon polaritons (SPPs) coupled with waveguide modes offer enhanced sensitivity for biosensing applications.
• Titanium nitride (TiN) is a promising material for plasmonic devices due to its unique optical properties and compatibility with fabrication techniques.

Purpose of the Study:

• To develop and characterize high-sensitivity biosensors utilizing the coupling of SPPs on TiN and planar waveguide modes.
• To evaluate the sensing performance of these devices for media with refractive indices relevant to biological materials.

Main Methods:

• Fabrication of Nb2O5/SiO2/TiN multilayer structures on sapphire prisms using dc magnetron sputtering.
• Attenuated Total Reflection (ATR) experiments in Kretschmann configuration to analyze plasmonic behavior.
• Fitting ATR spectra using the transfer-matrix method to understand Fano resonances and their dependence on refractive index.

Main Results:

• Demonstrated biosensors capable of sensing media with refractive indices from 1.0 to 1.6.
• Observed sharp reflectivity peaks (Fano resonances) in ATR spectra, highly sensitive to the refractive index of the sensing medium.
• Found that angular sensitivity and figure of merit increase with the refractive index of the sensing medium.

Conclusions:

• The developed TiN-based biosensors exhibit high sensitivity and are suitable for detecting materials of biological interest.
• The Fano resonances provide a strong signal for refractive index sensing, enabling precise material characterization.
• These biosensors hold potential for applications in diagnostics and biomolecular detection.