Remote plasmonic-enhanced Raman spectroscopy with the plasmon-molecule coupling in distance over 100 nm

<jats:p>We propose remote plasmonic-enhanced Raman scattering (RPERS) spectroscopy for molecular sensing and imaging applications. RPERS requires no contact between analyte molecules and metallic nanostructures, which overcomes the limitations of surface-enhanced Raman scattering (SERS). We constructed RPERS substrates consisting of silver nanoislands and columnar silica structures, which demonstrated a 2×10<jats:sup>7</jats:sup> enhancement in Raman scattering for Rhodamine 6G molecules, even when the metal nanostructures and analyte molecules were over 100 nm apart. The RPERS substrate also exhibited improved reproducibility (<15% RSD), long-term stability (>1 month), and sensitivity (>10 times) compared to conventional SERS substrates. We also confirmed the feasibility of RPERS for biophotonic analysis, i.e., enhancing Raman histological imaging of oesophagus tissues with oesophageal adventitia of a Wistar rat attached atop the columnar silica structure layer. Our demonstration is a promising advancement in the field of enhanced spectroscopy using plasmon and offers a solution to the challenges faced by conventional SERS spectroscopy. It has the potential to pave the way for future developments in remote plasmonic-enhanced spectroscopy.</jats:p>