CREOL Room 103
Department of Materials Science and Engineering
Pennsylvania State University
Plasmonics and gradient refractive index (GRIN) optics provide unique opportunities to engineer material systems capable of novel properties that lie outside what is found in nature. Meanwhile, the fabrication of plasmonic devices and GRIN lenses has typically involved multi-step processes such as electron beam evaporation, lithography and lamination, typically limited to the front or back surface of device structures. Ion and laser irradiation has emerged as promising approaches to generate a wide variety of self-assembled nanostructures. While irradiation has been traditionally considered destructive and therefore contrary to most plasmonic and optical material manufacturing strategies, key ion-solid and light-matter interactions have been creatively exploited to enable the seemingly-destructive method to constructively fabricate structures, realizing counterintuitive results in the form of advanced functionalities. In this talk, I will focus on the influences of energetic ion and laser beams on a wide range of material systems including III-V compound semiconductors and chalcogenide glasses at the nanoscale and the formation of spatially-controlled nanostructures with desirable properties in the matrices. These technologies are promising for next generation plasmonic and transmissive optical applications.
The first part of my talk will focus on the utilization of focused ion beam (FIB) irradiation on a wide range of III-V semiconductors to self-assemble a wide variety of nanostructures including nanoparticles, nanorods and nanochains [1-5]. Furthermore, I will present our recent results on the utilization of the tunable localized surface plasmon resonance energies in the FIB-assembled nanopartice arrays to enhance light emission efficiencies of compound semiconductors, thereby providing a promising alternative to plasmonic materials [6-8]. The second part of my talk will focus on our recent progress in creating advanced optical functionality in chalcogenide-based nanocomposites for diverse applications. Specifically, our research team was the first to utilize laser exposure on chalcogenide glasses to create spatially-controlled metallic nanocrystals with refractive indices greater than those of glass matrices at temperatures lower than those required in traditional processes. This approach enables gradient GRIN lenses expected to replace complex optical components, thereby opening up new opportunities for researchers to exploit increased design flexibility and cost-effectiveness for future microlens-based devices . Lastly, I will discuss questions which emerge as consequences of my research projects, and propose near future plans to develop a broadly applicable toolkit that will enable tailoring light-matter interactions for a wide range of applications in plasmonics, GRIN optics and the hybrid technology combining these two emerging fields, named GRIN-Plasmonics.