Technical Description: This project investigates, experimentally and theoretically, mechanisms of energy transfer between metal nanoparticles and laser dye molecules when both are photoexcited. Under these circumstances, metal excitations (plasmons) can interact with molecular excitations (excitons) to produce exciton populations with sufficient density (gain) to exhibit lasing. Both nanoparticle arrays and isolated nanoparticles are of interest in these studies, as both define optical cavities that can localize light to enhance gain and reduce the threshold for lasing. The effect of position and orientation of molecular emitters near the metal structures are being studied to determine which optical cavities optimize population inversion at the microscopic and nanoscopic levels and the lasing threshold at the macroscopic level. Theoretical models are being developed which couple electrodynamics calculations to the rate processes which govern exciton photophysics to simulate experiment. This work builds on an established experiment-theory track-record on understanding light-matter interactions in a range of nano-plasmonic systems. It extends passive structures considered previously to active and hybrid plasmonic architectures for applications in lasing, enhanced gain properties, and sensing.
Non-technical Description: This work develops a new class of lasers having subwavelength dimensions in at least one dimension, which will provide new opportunities for making ultrasmall optoelectronic devices. Such devices can have a direct and substantial impact on high-speed optical communication, high-density information storage, and nanolithography. Coupled with this basic research is a program in middle/high school and undergraduate curriculum development aimed at bringing leading-edge scientific activities in nanofabrication and manipulating light in the nanoworld. All the curricula are available online and through the Materials World Modules site. Also, a program of outreach on publication practices and ethics is aimed at producing better scientific papers and ultimately better science.
