Mixed Dimer Double-Resonance Substrates for Surface-Enhanced Raman Spectroscopy

Surface-enhanced Raman spectroscopy is performed on pairs of gold nanoparticles, for Which the nanoparticles in each pair have different shales'. The dimers therefore exhibit two plasmon resonances. These structures, termed Mixed dimer double-resonance substrates, enable strong field enhancement at pump and Stokes frequencies in surface-enhanced Raman spectroscopy. The extinction spectra of mixed diners are measured and simulated to their plasmon resonances. The experimentally determined enhancement factors of double-resonance structures are compared to those of single-resonance substrates.