Nanocrosses with Highly Tunable Double Resonances for Near-Infrared Surface-Enhanced Raman Scattering

We present asymmetric gold nanocrosses with highly tunable double resonances for the near-infrared (NIR) surface-enhanced Raman scattering (SERS), optimizing electric field enhancement at both the excitation and Stokes Raman wavelengths. The calculated largest SERS enhancement factor can reach a value as large as1.0×1010. We have found that the peak separation, the resonance position, and peak intensity ratio of the double-resonance gold nanocrosses can be tuned by changing the structural dimensions or the light polarization.