Collaborative Research: Strong and Weak Vibrational Coupling and Energy Dissipation for Metal Nanostructures

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Hartland of the University of Notre Dame and Professor Masiello of the University of Washington are studying how nanomaterials interact with their environment. The work will involve measurements of the vibrations of the nanomaterials, and comparison of the experimental data to theory. The results from these studies will generate new information about how nanostructures absorb and reflect acoustic waves, which is important for sonar applications, and the conversion of elastic energy into heat, which is critical for understanding fatigue in materials. The information from this project will also be important for improving the performance of sensors made from nano-optomechanical devices, and for understanding the distances over which nanomaterials feel their environment. The research will be carried out by graduate and undergraduate students from the Universities of Notre Dame and Washington (as well as undergraduate students from nearby primarily undergraduate institutions), and high school students from local school districts. By performing the research in this project these students will learn the critical-thinking skills necessary to become the next generation of leaders in science and technology. With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Hartland of the University of Notre Dame and Professor Masiello of the University of Washington are studying the frequencies and lifetimes of nanostructure vibrations using a combined experimental/theoretical modeling approach. Transient absorption microscopy experiments will be used to interrogate single nanoparticles to generate precise information about the homogeneous dephasing times of their vibrations. The theory involves the development of a Green’s function approach to describe the hybridization and decay of the acoustic modes of the particles, as well as the modified local density of acoustic states induced by the environment. The results from this project will determine whether the properties of strongly coupled acoustic vibrations can be understood from the properties of the uncoupled modes, and whether “backaction” from reflected acoustic waves affects the vibrational lifetimes and/or frequencies of the nanostructures. The length scale over which the nanoparticle vibrations “feel” their environment will be investigated by studying single optically trapped particles. The way thermoelastic damping in metals is affected by frequency will also be investigated. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.