Single-nanomaterial spectroscopic (SNS) techniques are widely used to investigate many physical, chemical, and biophysical phenomena which cannot be accurately determined by ensemble measurements. The merit of SNS is that it overcomes the disadvantage of sample polydispersity, which often masks important dynamical processes. My current research entails the synthesis and the study of the ultrafast dynamics of single metal nanoparticles with different local environments using transient absorption microscopy (TA). This is done to determine the damping rates of the acoustic vibrations in single gold nanoparticles which relates to time scales at which energy dissipates to the environment. This work requires the combination of Spatial Modulation Spectroscopy (SMS) to determine the size of the Au nanoparticle optically, with correlated transient absorption measurements on the individual nanoparticle. To optimize the set-up and achieve shot-noise limited detection the laser was modulated using an acousto optic deflector (AOD) or a galvo mirror (GM). Another project in which I am involved deals with the probing of propagation lengths of surface plasmon polaritons (SPPs), in chemically synthesized gold nanoplates. This 2D material is useful for the creation of optical devices with nanoscale dimensions that guide electromagnetic energy with a lateral mode confinement below the diffraction limit of light. In this work single crystalline, micrometer-sized plates are formed by using a modified polyol protocol. Their physical dimensions were measured using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The synthesis, characterization, growth mechanism and SPP propagation studies will be presented along with results from SMS and TA measurements.

Single nanomaterial dynamics and imaging of gold spheres and plates

246th National Meeting (2013)

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