Resonance properties of thick plasmonic split ring resonators for sensing applications

Area of Science:

• Nanophotonics and Metamaterials
• Optical Sensing Technologies

Background:

• Split ring resonators (SRRs) are key metamaterials for manipulating light.
• Understanding the optical response of SRR arrays with varying thickness is crucial for device optimization.
• Fabry-Perot resonances in nanostructures can influence overall optical properties.

Purpose of the Study:

• To investigate the optical response of dense split ring resonator (SRR) arrays as a function of thickness.
• To explore the excitation of vertical Fabry-Perot resonances and their interaction with horizontal SRR resonances.
• To assess the potential of these nanostructures for biochemical sensing applications.

Main Methods:

• Detailed optical response measurements of SRR arrays in the VIS-NIR spectral range.
• Fabrication of well-ordered, large arrays of thick SRRs using X-ray lithography.
• Numerical simulations to model and compare with experimental transmittance data.

Main Results:

• Discovery of vertical Fabry-Perot resonances in sufficiently tall SRRs.
• Observation of interactions between vertical Fabry-Perot and horizontal SRR resonant modes.
• Demonstration that the coexistence of these resonances increases sensing sensitivity.
• Excellent agreement between numerical and experimental transmittance results.

Conclusions:

• Thick SRR arrays support complex resonant behaviors, including vertical Fabry-Perot modes.
• The combined resonances offer enhanced sensitivity, making them suitable for biosensing.
• X-ray lithography enables the fabrication of large, ordered arrays for practical applications.
• Preliminary tests confirm the potential of these SRR geometries as effective sensing platforms.