OP: Coherence and Energy Transfer Processes in Lattice Plasmon Lasers

This proposal describes experimental and theoretical studies of the mechanisms of coherence and energy transfer processes in nanoscale lasers based on arrays of metal nanoparticles (NPs), in which surface plasmon excitations can drive stimulated emission in organic dyes and other gain materials. In our prior work supported by NSF, we (Odom and Schatz) achieved lasing action from engineered nanocavities with feedback mediated by lattice plasmons as well as surface plasmon polaritons. Lattice plasmons are excitations that arise from the diffractive coupling between localized surface plasmons in metal NPs in a periodic array. This coupling leads to hybrid plasmonic/photonic modes with narrow linewidths (< 4 nm) and a high local density of optical states that can be exploited for lasing at room-temperature. The emission can also be tuned in real time using liquid gain media in an opto-fluidic device. Although we have a cursory understanding how dye molecules affect population inversion at the nanoscopic level and lasing at the macroscopic level, the detailed mechanism is unknown since coherence and ultra-fast studies have been lacking. We propose to address this knowledge gap in nano-lasers using lattice plasmons as a model optical feedback system