제   목   Single particle microscopy and spectroscopy of gold nanorods for their photothermal applications
강   사   Dr. James W. M. Chon
소   속   Swinburne University of Technology, Australia
시   간   2009년 11월 24일 (화요일) 오전 11시
장   소   제1 신공학관 301동 1121호

Abstract
Recent developments in controllable synthesis of anisotropic nanomaterials have led to the advances in their optical, electronic and chemical functionalities. Noble metallic nanorods are one such class of material that has fascinating optical functionalities mediated by surface Plasmon resonance (SPR).  The SPR oscillation along the longitudinal direction of the rod can be tuned spectrally with aspect ratio of the rod and the magnitude with its orientation, making it a perfect material for selective optical addressing with respect to the spectrum and polarization. It also boasts enhanced linear and non-linear absorption which can be extremely beneficial in photothermal applications such as optical recording1-2 and photodynamic therapy.
Despite their promising functionalities and applications, their fundamental physical properties such as melting temperature, Young’s modulus and absorption cross sections are yet to be accurately determined, partly because of ensemble averaging in measurements. These properties are extremely important for above mentioned applications. Recently we have been able to accurately determine these properties of gold nanorods (width 30 nm, aspect ratio 3) by performing time-resolved transient absorption and white light scattering spectroscopy/microscopy at single particle level1-4. The time-resolved study showed that the pump pulse launches acoustic vibrations of the rods due to fast Plasmon-phonon coupling (1-3 ps), from which the Young’s modulus of the rods were measured3. Further, the white light scattering is used to probe the of the rod shape transition with respect to laser pulse, accurately determining the melting temperature of the rods4. Surprisingly, the Young’s modulus and melting temperature of the gold nanorods were found to be very close to the bulk values of the gold, contrasting earlier reports by others.    
In this talk, I will present details of our single particle microscopy/spectroscopy results on gold nanorods, determining some of the most fundamental physical properties of gold nanorods. I will also present the demonstration of five-dimensional optical recording and readout using gold nanorods1 and possible other photothermal applications arising from this study.

강사이력
James W. M. Chon received his PhD in 2001 at the University of Melbourne in Australia under the supervision of Prof. Paul Mulvaney. He joined the Centre for Micro-Photonics (CMP) at Swinburne University of Technology, Australia in 2001 as a postdoctoral research fellow, where he was later promoted to Lecturer (2004) and Senior Lecturer (2005), and he holds the latter post until now. Since joining CMP, his field of research expanded to nonlinear microscopy/spectroscopy of the nanoparticles, optical trapping, and next generation optical storage.