Simultaneous Surface-Enhanced Raman Scattering with a Kerr Gate for Fluorescence Suppression

Area of Science:

• Spectroscopy
• Surface Science
• Nanotechnology

Background:

• Fluorescence often overwhelms weak Raman signals, limiting analysis of certain analytes.
• Optical Kerr-gated Raman spectroscopy offers temporal resolution but requires signal enhancement.
• Surface-enhanced Raman scattering (SERS) significantly amplifies Raman signals.

Purpose of the Study:

• To combine SERS with Kerr-gated Raman spectroscopy for enhanced signal and fluorescence suppression.
• To expand the applicability of Kerr-gated Raman spectroscopy to highly fluorescent media.
• To demonstrate the method's effectiveness for analytes with weak Raman signals.

Main Methods:

• Utilized SERS-active gold substrates with varying roughness and gold-core-shell-isolated nanoparticles (SHINs).
• Employed optical Kerr-gated Raman spectroscopy in conjunction with SERS substrates.
• Investigated the spectral analysis of rhodamine 6G, Nile red, and Nile blue dyes.

Main Results:

• Successfully obtained well-defined Raman spectra of fluorescent dyes using the combined technique.
• Demonstrated significant enhancement of weak Raman scattering via SERS substrates.
• Showed that SHINs enabled measurements on non-SERS-active substrates (Au, Cu, Al).

Conclusions:

• The combination of SERS and Kerr-gated Raman spectroscopy effectively enhances Raman signals and suppresses fluorescence.
• This integrated approach broadens the scope of Raman spectroscopy for studying challenging analytes in fluorescent environments.
• The use of SERS substrates, particularly SHINs, is crucial for analyzing weak Raman signals in complex media.