Share Email Print

Proceedings Paper

Analysis of photoacoustic response from plasmonic nanostructures irradiated by ultrafast laser in water (Conference Presentation)
Author(s): Ali Hatef; Behafarid Darvish; Adrien Dagallier; Christos Boutopoulos; Michel Meunier

Paper Abstract

Gold and silver plasmonic nanoparticles (NPs) are widely used as a contrast agent for photoacoustic (PA) imaging, taking advantage of the strong optical absorption cross-section of these particles due to their localized surface-plasmon resonance. Inspired by recent developments in ultra-high frequency wide-bandwidth transducers, we propose utilizing off-resonance ultrashort laser sources with a pulse width in the femtosecond (fs) and picosecond (ps) range to increase the efficiency of PA imaging. Also, from the fact that the laser pulse duration is shorter than the heat diffusion time of the materials, we expect practically no collateral damage of the laser irradiated biological tissues. Our preliminary studies show that irradiating the NPs with an ultrashort-pulsed laser has the potential to achieve substantially higher efficiency at generating the PA signal. Enhanced by the presence of NPs, the laser field causes a highly localized plasma nucleation around the vicinity of the NPs. Plasma relaxes through electron-ion interaction and releases a pressure wave in the surrounding medium. However, in this process, it is crucial to precisely control the heat energy absorption in the NPs to avoid their fragmentation. In this talk we present a model to simulate an optimized plasma–mediated PA signal dynamics generated from off-resonance ultrashort laser excitation (λ =800 nm, τ = 70 fs – 2 ps) of a variety of plasmonic NPs with sizes ranging from 50 nm to 100 nm.

Paper Details

Date Published: 27 April 2016
PDF: 1 pages
Proc. SPIE 9708, Photons Plus Ultrasound: Imaging and Sensing 2016, 970819 (27 April 2016); doi: 10.1117/12.2207841
Show Author Affiliations
Ali Hatef, Nipissing Univ. (Canada)
Behafarid Darvish, Nipissing Univ. (Canada)
Adrien Dagallier, École Polytechnique de Montréal (Canada)
Christos Boutopoulos, Ecole Polytechnique de Montréal (Canada)
Michel Meunier, Ecole Polytechnique de Montréal (Canada)

Published in SPIE Proceedings Vol. 9708:
Photons Plus Ultrasound: Imaging and Sensing 2016
Alexander A. Oraevsky; Lihong V. Wang, Editor(s)

© SPIE. Terms of Use
Back to Top