The random laser has the potential to be replaced with the conventional cavity laser for abundant nanophotonics applications. For this purpose, it is essential to investigate the effect of using different materials as the diffusive medium in the random laser. We theoretically studied two groups of diffusive nanoparticles with some common materials used in the random lasers: metals (Au, Ag, Al) and dielectrics (TiO2, Si, GaAs). First, we compared the random lasing behavior with metal and dielectric triangle/sphere nanoparticles through the scattering cross section calculations. Then, the physical characteristics of triangle/sphere nanoparticles of both categories were investigated, resulting in the optimum scattering condition for the nanoparticles. Noteworthy, we have supposed that the triangle nanoparticles are made with colloidal lithography and randomly distributed in Rhodamine 6G as a gain medium for all simulations. We investigated that aluminum and titanium dioxide are good scatterers to interact with the gain medium over the photoluminescence emission spectrum. This study paves the way to design a more effective and applicable random laser for many potential applications.

in them are essential to explore the plasmonic behavior at various interfaces. Dielectric can be as inorganic and organic; its selection depends on their attributes. Presently organic materials are particularly attractive due to their long exciton lifetime which makes strong modal coupling in interaction with SPP probable. [4] To achieve strong coupling, organic material ought to possess limited transition linewidth [5] like using J-aggregate molecules at plasmonic interfaces. [6] But J-aggregate molecules require special environmental prerequisites to function properly and maintain stable interaction. In this study, we used small florescent molecule to investigate the strong modal coupling at the organic/ plasmonic interface. We focus on the strong modal coupling of plasmonic microcavity using florescent organic material, EY51 (Rubrene-like), in dielectric medium of plasmonic microcavity. The introduction of an active medium has effectively introduce a loss-compensated channel in the microcavity. We believe the interaction of active medium cavity and plasmonic nanostructure has generated a new plasmonic system that can open up a new degree to control modal coupling, analogous to the modal coupling control in parity-time symmetry system; we observed anticrossing with large Rabi-analog splitting at cavity mode-SPP coupling in large area hybrid plasmonic microcavity. We also investigated the luminescence intensity which acts as loss-compensation impact on the coupling strength of cavity. In addition, the photoluminescence (PL) emission measurement was carried out for plasmonic and photonic microcavity which acquired higher intensity of PL emission in the plasmonic cavity than that of photonic. The device was fabricated with conventional photolithography to provide the required practicality and cost-efficiency of mass production for various applications. [7] TheoryThe light-matter interaction at the plasmonic microcavity can be broadly described by the following Hamiltonian [8] cav c av spp s ppwhere ω cav and ω spp are, respectively, the resonant frequencies of the cavity mode and SPP mode, Γ cav and Γ spp represent the Here it is studied how the active medium affects the Rabi-analog splitting when an active plasmonic microcavity mode is coupled to a surface plasmon polariton mode. The incorporation of Rubrene-like molecules in the plasmonic microcavity results in stronger modal coupling. Anticrossing is observed with a large Rabi-analog splitting energy of 280 meV in the strong coupling regime. The active medium contributes to the split enhancement through channeling more energy toward the coupling. The variation of photoluminescence emission and exciton-cavity mode coupling from the hybrid plasmonic microcavity are also measured. This work shows that by introducing an active medium in the microcavity, mode coupling between microcavity and surface plasmon polariton can be enhanced and the hybrid plasmonic device exhibits paritytime symmetry characteristics.

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