Showing papers by "Peter Zijlstra published in 2008"

Acoustic Oscillations and Elastic Moduli of Single Gold Nanorods

Abstract: We present the first acoustic vibration measurements of single gold nanorods with well-characterized dimensions and crystal structure The nanorods have an average size of 90 nm × 30 nm and display two vibration modes, the breathing mode and the extensional mode Correlation between the dimensions obtained from electron microscope images and the vibrational frequencies of the same particle allows us to determine the elastic moduli for each individual nanorod Contrary to previous reports on ensembles of gold nanorods, we find that the single particle elastic moduli agree well with bulk values

Fabrication of Low-Threshold 3D Void Structures inside a Polymer Matrix Doped with Gold Nanorods

Abstract: We report on a low-threshold three-dimensional (3D) void generation inside a polyvinyl-alcohol (PVA) polymer matrix doped with gold nanorods (NRs) by near infra red femtosecond laser pulses. By matching the laser wavelength to the surface plasmon resonance band of the embedded gold NRs, the void generation threshold could be reduced by one order of magnitude lower than undoped matrix. We discuss physical mechanisms involved in the void generation, where distinction between the decomposition of gold NR or PVA is drawn in single pulse and multiple pulse irradiations. We also demonstrate 3D void recording for applications in 3D optical data storage.

Numerical optimization of gold-dielectric nanoparticle heterostructures for surface plasmon resonance engineering

Abstract: Metallic nanoparticles are a very attractive and fascinating material due to their multifunctional properties, such as surface plasmon resonance absorption and excitation band tuning. In particular, these properties are proved to be valuable in photothermal therapeutic applications, where the tunable, efficient near-field enhanced ablation or photothermal energy conversions can be used to destroy cancerous cells. A similar mechanism can be applied for threedimensional multilayer nanopatterning of polymer matrix doped with NPs, where the field enhancement and photothermal energy conversion are utilised to produce micro-explosions and voids. Previously, it was reported that engineering the morphology of nanoparticles (rod and shell shape) can greatly enhance the field enhancement and photothermal conditions. Here, we numerically study the field enhancement efficiencies of nanparticles with heterogeneous morphologies (such as metal - dielectric - metal core-shell structures), and compare their efficiencies to conventional nanosphere and nanoshell structures. Unlike the previous approximate analytical models, the SPR excitation and field enhancement efficiencies are numerically simulated, using the frequency-dependent finite-difference time domain method under tightly focused ultrashort pulse laser irradiation to accurately emulate the experimental conditions.