Light-Induced Heating of Gold Nanoparticles in Colloidal Solution: Dependence on Detuning from Surface Plasmon Resonance

The absorption of light by gold nanoparticles in colloidal water solution has been studied at the simultaneous illumination of nanoparticles by the continuous wave laser beam in dependence on the detuning of laser frequency from the surface plasmon resonance. The appreciable blue shift, broadening, and increase of intensity of the plasmonic absorption band have been observed at approaching of the laser frequency to surface plasmon resonance in Au nanoparticles. The plasmon band broadening reveals the heating of gold nanoparticles that has an evident resonant character. The strong increase of nanoparticle temperature of 316 K has been obtained at moderate laser intensity of 5 × 103 W/cm2 and detuning of 28.5 nm. The sharp blue shift of plasmon band was observed when the temperature exceeded the water boiling point. Such effect is probably due to formation of the vapor bubbles around the Au nanoparticles occurring at water boiling.