Measuring of translational and rotational local temperatures of a single gold nanocrescent in glycerol

Abstract The gold nanocrescent (NC) particles possess a strong plasmon resonance which gives them a strong scattering cross section. They can thus be easily tracked using dark-field microscopy. In this study, we improved the optical configuration setup of dark-field video microscope to simultaneously measure the translational and rotational local temperatures within a glycerol medium. The translational and rotational local temperatures have been measured on the same single gold nanocrescent particle when it was excited by green and red laser. The rotational local temperature was measured by the technique of rotational scattering correlation spectroscopy (RSCS) and the translational local temperature was measured by tracking a single nanoparticle technique through the determination of translational diffusion coefficient under Brownian motion. The result showed that the translational local temperature was significant lower than the rotational local temperature for the same single gold nanocrescent. Remarkablely, we can affirm that the heterogeneity of the optical environment leads to the difference between these two temperatures. The obtained results have a great potential to probe the local nanorheology of a material.