Combinatorial Single Particle Spectro-Microscopic Analysis of Plasmon Coupling of Gold Nanorods on Mirror

A highly correlative spectro-microscopy system was developed that combines reflected dark-field microscopy and total internal reflection scattering microscopy imaging modes with a spectrometer. This instrument facilitates the study of the particle on a mirror system by correlating the scattering images and spectra under the two different excitation schemes. Interestingly, the total internal reflection scattering microscopy reveals multiple plasmonic coupling modes that are not observed for the exact same gold nanorod in reflected dark-field microscopy. It suggests distinct plasmon coupling mechanisms for a gold nanorod on a mirror: only a single out-of-plane coupling mode is observed with reflected dark-field microscopy, while both in-plane and out-of-plane coupling modes are uncovered in total internal reflection scattering microscopy. By introducing an analyzer into the collection optics, the relative orientation of gold nanorods to the incident direction of laser beam displays large effects on the far-field scattering images and spectra.

Automated summary

The system combines different imaging modes and spectral analysis methods for studying plasmon coupling mechanisms of gold nanorods on a mirror. Total internal reflection scattering microscopy reveals multiple coupling modes not observed in reflected dark-field microscopy.