Surface-enhanced hyper-Raman spectroscopy using optical trapping of silver nanoparticles for molecular detection in solution

This is the authors' abstract. We don't add key points for this paper.

Optical trapping of silver nanoparticles dispersed with rhodamine 6G (R6G) and NaCl in water gives surface-enhanced hyper-Raman scattering (SEHRS) of R6G. In this paper we have measured the SEHRS spectrum in the R6G concentration range between 10−7 and 10−11 M. SEHRS intensity and signal-to-noise ratio show clear differences at the lower R6G concentrations than ~10−9 M, indicating that the number of R6G in a trapped silver aggregate approaches the single-molecule level. This trapping SEHRS technique is applied for the detection of lysozyme molecules labelled with tetramethylrhodamine dye.