Metallic nanoparticles exhibit a plasmon resonance at optical frequencies that enables efficient conversion of optical to thermal energy at the nanoscale. This photothermal coupling can be leveraged for various applications using femtosecond-pulsed laser illumination tuned to the plasmon resonant frequency. Recent applications of this phenomenon include novel therapeutic and imaging modalities at the cellular level in the emerging field of nanomedicine. The response of a metallic nanoparticle to laser illumination and resulting thermal effects depend on many factors including the optical absorbance cross-section of the particle, the fluence and pulse duration of the laser and mechanisms of heat transfer to surrounding media. Aside from the primary effect of heating the particle itself, secondary effects include diffusion of heat in the surrounding media and vapor bubble nucleation if the temperature at the surface of the particle exceeds the vaporizaton threshold of the media. In this presentation we present a discussion and analysis of nanoscale plasmon-assisted bubble nucleation. We use computational electromagnetics to study the wavelength dependent absorption of various metallic nanostructures and computational fluid dynamics (CFD) to study the nucleation, growth and collapse of nanobubbles around these structures. We study the basic physics of the vaporization process and discuss novel applications.
Journal: TechConnect Briefs
Volume: 2, Nanotechnology 2011: Electronics, Devices, Fabrication, MEMS, Fluidics and Computational
Published: June 13, 2011
Pages: 470 - 473
Industry sectors: Advanced Materials & Manufacturing | Sensors, MEMS, Electronics
Topic: Micro & Bio Fluidics, Lab-on-Chip