(37g) Nanoscale Thermal Dissipation and Heat Transport by Continuous Wave Laser Induction of Localized Surface Plasmon Resonance in Gold Nanoparticles

Ahn, W., University of Utah
Roper, D. K., University of Arkansas

Surface plasmon resonance (SPR) is collective oscillation of delocalized noble metal electrons polarized by incident resonant photons. SPR electron oscillation dissipates thermal energy via electron-phonon and phonon-lattice processes in picoseconds within 20-200 nm of gold surfaces. We report induction of thermal dissipation via localized SPR (LSPR) in thermally-isolated aqueous suspensions of gold nanoparticles (AuNP) using continuous wave (CW) resonant laser light. Effects of CW laser power, wavelength and AuNP concentration on the efficiency of transducing resonant light to thermal energy via LSPR at 20-nm AuNP surfaces are measured in a medium vacuum system. An integrated mathematical description of heat transfer by radiation, conduction and convection is applied to quantify heat transfer in CW-excited AuNP suspensions. Local temperature profiles surrounding suspended AuNP and time constants for thermal dissipation into surrounding media are calculated. Stability of AuNP suspensions subject to resonant CW laser excitation is studied using UV-vis spectroscopy. Conditions to predictably and reproducibly transduce resonant CW laser energy to thermal energy in aqueous AuNP suspensions via LSPR are identified.