Method of optical manipulation of gold nanoparticles for surface-enhanced Raman scattering in a microcavity

In this study, an optical manipulation and micro-surface-enhanced Raman scattering (microSERS) setup based on a microcavity was developed for efficient capture of gold nanoparticles using the photothermal effect. In addition, optical manipulation of gold nanoparticles and SERS signal detection were performed using only one laser. The results show that the SERS enhancement effect based on the microcavity was more than 20 times that based on a gold colloid solution. The laser power and velocity of nanoparticles exhibited a good linear relationship, and the velocity of nanoparticles decreased with decreasing radius r, which verifies the detriment of the radial thermophoresis in this study. This method can be used to quickly and efficiently drive metal nanoparticles and provides a promising approach for analysis of substances in the fields of chemistry and biology.