CHARACTERIZATION OF FLUORESCENCE FROM QUANTUM DOTS ON NANOSTRUCTURED METAL SURFACES

The behavior of fluorescent materials coupled to surface plasmon supporting surfaces and structures is an area of active research due to their fluorescence enhancing properties. The inherent field enhancements present near structures and interfaces where surface plasmons are excited provide great potential for increasing the response of many optical interactions. While many studies focus on the application of plasmonic nanoparticles or finite metallic structures the use of dielectric structures on a continuous metallic film has received little attention. A comprehensive experimental study using dielectric gratings on gold films is presented illustrating the fundamental properties of fluorescence enhancement on such structures. A process for fabrication of samples using Electron Beam Lithography is demonstrated and comparisons between various quantum dot deposition methods are made to determine the best conditions for surface coating. Conditions for optimization of the fluorescence enhancement phenomena for practical application are explored for gratings with square function profile illustrating the influence of gratings on fluorescence behavior and identifying conditions for optimal enhancement. Complementing these results, an understanding of the underlying physical phenomena is developed by differentiation between enhanced emission and enhanced absorption effects using measurements of fluorescence decay lifetime and emission spectra. Using these observations a thorough description of these systems and the requirements for their practical application is illustrated

Hyperbolic metamaterial interfaces: Hawking radiation from Rindler horizons and the "end of time"

Extraordinary rays in a hyperbolic metamaterial behave as particle world lines in a three dimensional (2+1) Minkowski spacetime. We analyze electromagnetic field behavior at the boundaries of this effective spacetime depending on the boundary orientation. If the boundary is perpendicular to the space-like direction in the metamaterial, an effective Rindler horizon may be observed which produces Hawking radiation. On the other hand, if the boundary is perpendicular to the time-like direction an unusual physics situation is created, which can be called "the end of time". It appears that in the lossless approximation electromagnetic field diverges at the interface in both situations. Experimental observations of the "end of time" using plasmonic metamaterials confirm this conclusion.Comment: 21 pages, 4 figure

Experimental Modeling of Cosmological Inflation with Metamaterials

Recently we demonstrated that mapping of monochromatic extraordinary light distribution in a hyperbolic metamaterial along some spatial direction may model the flow of time and create an experimental toy model of the big bang. Here we extend this model to emulate cosmological inflation. This idea is illustrated in experiments performed with two-dimensional plasmonic hyperbolic metamaterials. Spatial dispersion which is always present in hyperbolic metamaterials results in scale-dependent (fractal) structure of the inflationary "metamaterial spacetime". This feature of our model replicates hypothesized fractal structure of the real observable universe.Comment: 17 pages, 3 figures. This version is accepted for publication in Physics Letters

Hyperbolic metamaterial interfaces: Hawking radiation from Rindler horizons and spacetime signature transitions

Extraordinary rays in a hyperbolic metamaterial behave as particle world lines in a three-dimensional (2 + 1) Minkowski spacetime. We analyze electromagnetic field behavior at the boundaries of this effective spacetime depending on the boundary orientation. If the boundary is perpendicular to the spacelike direction in the metamaterial, an effective Rindler horizon may be observed, which produces Hawking radiation. On the other hand, if the boundary is perpendicular to the timelike direction, the system undergoes a phase transition to a state with a different nature of the spacetime, with nonintegrable field divergence at the transformation point. Experimental observations of the transition using plasmonic metamaterials confirm this conclusion