Three-Dimensional Metamaterial for Plasmon-Enhanced Raman Scattering at any Excitation Wavelengths from the Visible to Near-Infrared Range.

Plasmonic materials with highly confined electromagnetic fields at resonance wavelengths have been widely used to enhance Raman scattering signals. To achieve the maximum enhancement, the resonance peaks of the plasmonic materials should overlap with the excitation and emission wavelengths of target molecules, which is difficult for most of the plasmonic materials possessing a few narrow resonance peaks. Here, we report an ultrabroadband plasmonic metamaterial absorber (BPMA) that can absorb 99% of the incident light energy and excite plasmon resonance from the ultraviolet to near-infrared range (250-1900 nm), which allows us to observe efficient plasmon-enhanced Raman scattering (PERS) with any excitation sources. As demonstrated by the investigation on a self-assembled monolayer of the nonresonant molecule 4-mercaptobenzonitrile, the BPMA exhibits high PERS performance with a detection limit of down to 10-12 M under any excitation sources of three different lasers and excellent uniformity (∼5.51%) and reproducibility (∼5.50%), which corroborates the potential for high-throughput production with low cost and at a large scale. This work offers a novel platform for anti-interference PERS analysis in dynamic and complex environments.