Optofluidics driven by photothermal effects of single gold nanoparticles

Gold nanoparticles (Au NPs) exhibit strong light absorption due to localized surface plasmon resonance (LSPR), and efficiently convert light energy into heat under illumination. Heat transfer from Au NPs to surrounding matrices induces an increase in temperature, resulting in nanobubbles generation owing to explosive evaporation of the medium. In particular, stationary bubbles can be produced by illuminating CW laser for single Au NPs. These stationary bubbles in microscopic region drive fluid convection of medium and suggest the potential application to the manipulation of colloidal particles and molecules. In the present work, we have investigated the thermo-physical properties of the stationary bubbles and fluid convection of surrounding water by integrating experimental results with those by the theoretical calculation.