Geometry-induced enhancement factor improvement in covered-gold-nanorod-dimer antennas

Area of Science:

• Plasmonics
• Nanophotonics
• Spectroscopy

Background:

• Gapped gold nanorod dimers support surface plasmon polaritons (SPPs) that enhance electromagnetic fields at the gap.
• This field enhancement is crucial for molecular detection via surface-enhanced Raman spectroscopy (SERS).
• Integrating electrical measurements with SERS requires careful nanoantenna design to maintain enhancement factors (EF).

Purpose of the Study:

• To theoretically investigate designs for contacting gold nanorods in dimers without reducing the SERS enhancement factor.
• To explore the feasibility of fabricating hybrid devices combining SERS and electrical measurements.
• To determine if geometrical modifications away from the dimer gap can improve optical response.

Main Methods:

• Theoretical study of illuminated gapped-gold-nanorod dimers.
• Engineering geometrical parameters to optimize electromagnetic field enhancement.
• Simulating designs with gold covering on far-from-the-gap areas of the dimer.

Main Results:

• Tuning geometrical parameters of covered dimers can achieve enhancement factors exceeding those of uncovered dimers.
• This enhancement superiority persists despite dimer asymmetries and interface vacancies.
• Geometrical modifications away from the gap positively influence the optical response at the gap.

Conclusions:

• Novel gold nanorod dimer designs with strategically placed gold coverings can enhance SERS performance.
• These designs are suitable for hybrid devices integrating SERS and electrical measurements.
• Optimizing geometry away from the active gap area offers a pathway to improved nanoantenna performance for optical and hybrid applications.