Engineered Multifunctional Nanophotonic Materials for Ultrafast Optical Switching.

摘要

This research was a comprehensive science and engineering program to develop a new generation of nanophotonic materials, structures, and devices exhibiting large, high-speed nonlinear optical (NLO) changes, as needed to enable new capabilities in all-optical switching for imaging applications. In particular, the problem of passive optical limiting and switching without using focusing optics is an extremely challenging task. The goal of this research was to tackle lensless optical limiting by determining the ultimate possibilities and limits on materials, materials structures, and device configurations. The approach we adopted combined three methodologies to achieve this goal: (1) to enhance the NLO response of the molecules through a variety of molecular engineering approaches, (2) to use surface plasmon field enhancements in nano- engineered clusters and arrays of metal and/or dielectric nanoparticles coupled to the organic NLO materials; and (3) to integrate the first two methodologies in systems having weakly resonant structures, including 3-D and/or 1-D photonic crystal structures (i.e. nonlinear Bragg mirrors). We made significant progress in all three areas and have observed orders of magnitude enhancement of NLO absorption; however, we have not been able to fully harness this enhancement for devices due to the transient nature of the effects.