(393b) Laser Induced Photothermal Heating and Bubble Generation of Gold Nanoparticles

Laser
Induced Photothermal Heating and Bubble Generation

of Gold Nanoparticles

I. H.
Karampelas¹ and E. P. Furlani^1,2

¹Dept. of Chemical and
Biological Engineering, ²Dept. of Electrical Engineering

 University at Buffalo, SUNY, NY 14260 USA

In this study, we present an analysis of photothermal
effects associated with nanosecond-pulsed, laser-illuminated gold nanoparticles
immersed in aqueous solutions. We use combined computational electromagnetic
and fluid analysis to model the fundamental aspects of this photothermal process.
More specifically, we study energy conversion within the nanoparticles at
plasmon resonance, heat transfer to the fluid, homogenous bubble nucleation and
the dynamic behavior of the bubble and surrounding fluid. In addition, we demonstrate
the theory via application to various nanoparticle geometries such as spheres,
rods and tori. We show that process parameters such as laser intensity, pulse
duration, wavelength, polarization and particle geometry can be tuned to control
the size and behavior of nucleated bubbles. Moreover, we present results on multi-particle
systems and demonstrate that cooperative heating allows for the generation of
larger bubbles using significantly less energy as compared to single-particle
systems. We discuss details of the modeling approach and specific applications
including recent advances in photothermal tissue therapy at the cellular level.