Research Projects

We propose an experimental study to characterize and enhance the properties of perovskite nanolasers, such as spatial coherence, chiral emission, and photon outcoupling, and suggest that using hyperbolic metamaterials, these properties of perovskite nanolasers are enhanced. This study is motivated by the hybrid organic-inorganic semiconductors CH3NH3PbX3, where X = I, Br, Cl (methylammonium lead halide perovskites) have shown to be the most promising material for photovoltaics. Solution-processable technology and the simple growth of single crystalline nanostructures make them ideal materials for nanowire lasers. Growing completely solution-processable single crystalline nanowires (NW) with ultra-low lasing thresholds is possible. High quantum efficiency, long carrier lifetime, and exciton diffusion length are the reasons for low threshold lasing in perovskite nanolasers. Low threshold lasing has been demonstrated using the perovskite nanolasers. However, underlying coherence properties still need to be studied, and little to no effort has been put into enhancing coherence, chiral emission, and photon outcoupling. We proposed one way to enhance coherence using perovskite nanolasers coupled with hyperbolic metamaterials. Hyperbolic metamaterials (HMM) are a new class of metamaterials with hyperbolic dispersion. Large wave vectors are allowed in hyperbolic metamaterials due to open hyperbolic topology. Hyperbolic dispersion allows spatially separated emitters (excitons) to interact through hyperbolic polaritons and support long-range dipole-dipole interactions, allowing long-range coherence in the perovskite nanolaser. In the case of chiral emission and photon outcoupling, we proposed a negative refractive index hyperbolic metamaterial nanocavity to generate chiral emission from the perovskite nanolaser and enhance outcoupling coherent photons to the far field. The hyperbolic negative metamaterial index nanocavities generate superchiral fields. Superchiral fields have chirality greater than the chirality of the right and left circularly polarized light in free space and enhance chiral emission from the perovskite nanolaser and photon outcoupling.