Surface plasmon toy-model of a rotating black hole

Recently introduced surface plasmon toy black hole model has been extended in order to emulate a rotating black hole (Kerr metric). Physical realization of this model involves a droplet of an optically active liquid on the metal surface which supports propagation of surface plasmons. Such droplets are shown to exhibit giant optical activity in the frequency range near the surface plasmon resonance of a metal-liquid interface.Comment: 4 pages, 4 figure

Using surface plasmonics to turn on fullerene's dark excitons

Using our recently proposed Bethe-Salpeter $G_0W_0$ formulation, we explore the optical absorption spectra of fullerene (C$_{60}$) near coinage metal surfaces (Cu, Ag, and Au). We pay special attention to how the surface plasmon $\omega_S$ influences the optical activity of fullerene. We find the lower energy fullerene excitons at 3.77 and 4.8 eV only weakly interact with the surface plasmon. However, we find the surface plasmon strongly interacts with the most intense fullerene $\pi$ exciton, i.e.\ the dipolar mode at $\hbar\omega_+\approx$ 6.5 eV, and the quadrupolar mode at $\hbar\omega_-\approx$ 6.8 eV. When fullerene is close to a copper surface ($z_0\approx$ 5.3 \AA) the dipolar mode $\omega_+$ and "localized" surface plasmons in the molecule/surface interface hybridize to form two coupled modes which both absorb light. As a result, the molecule gains an additional optically active mode. Moreover, in resonance, when $\omega_S\approx\omega_\pm$, the strong interaction with the surface plasmon destroys the $\omega_-$ quadrupolar character and it becomes an optically active mode. In this case the molecule gains two additional very intense optically active modes. Further, we find this resonance condition, $\omega_S \approx \omega_\pm$, is satisfied by silver and gold metal surfaces.Comment: 10 pages, 8 figure

Hybrid 1D Plasmonic/Photonic Crystals are Responsive to Escherichia Coli

Photonic crystal-based biosensors hold great promise as valid and low-cost devices for real-time monitoring of a variety of biotargets. Given the high processability and easiness of read-out even for unskilled operators, these systems can be highly appealing for the detection of bacterial contaminants in food and water. Here, we propose a novel hybrid plasmonic/photonic device that is responsive to Escherichia coli, which is one of the most hazardous pathogenic bacterium. Our system consists of a thin layer of silver, a metal that exhibits both a plasmonic behavior and a well-known biocidal activity, on top of a solution processed 1D photonic crystal. We attribute the bio-responsivity to the modification of the dielectric properties of the silver film upon bacterial contamination, an effect that likely stems from the formation of polarization charges at the Ag/bacterium interface within a sort of bio-doping mechanism. Interestingly, this triggers a blue-shift in the photonic response. This work demonstrates that our hybrid plasmonic/photonic device can be a low-cost and portable platform for the detection of common contaminants in food and water

Important Considerations in Plasmon-Enhanced Electrochemical Conversion at Voltage-Biased Electrodes.

In this perspective we compare plasmon-enhanced electrochemical conversion (PEEC) with photoelectrochemistry (PEC). PEEC is the oxidation or reduction of a reactant at the illuminated surface of a plasmonic metal (or other conductive material) while a potential bias is applied. PEC uses solar light to generate photoexcited electron-hole pairs to drive an electrochemical reaction at a biased or unbiased semiconductor photoelectrode. The mechanism of photoexcitation of charge carriers is different between PEEC and PEC. Here we explore how this difference affects the response of PEEC and PEC systems to changes in light, temperature, and surface morphology of the photoelectrode

Graphene Plasmonics for Terahertz to Mid-Infrared Applications

In recent years, we have seen a rapid progress in the field of graphene plasmonics, motivated by graphene's unique electrical and optical properties, tunabilty, long-lived collective excitation and their extreme light confinement. Here, we review the basic properties of graphene plasmons; their energy dispersion, localization and propagation, plasmon-phonon hybridization, lifetimes and damping pathways. The application space of graphene plasmonics lies in the technologically significant, but relatively unexploited terahertz to mid-infrared regime. We discuss emerging and potential applications, such as modulators, notch filters, polarizers, mid-infrared photodetectors, mid-infrared vibrational spectroscopy, among many others.Comment: Review articl

Unified evaluation of surface-enhanced resonance Raman scattering and fluorescence under strong coupling regime

We demonstrate importance of molecular multiple excitons and higher-order plasmons for both enhancement and quenching of resonance Raman and fluorescence of single dye molecule located at plasmonic hotspot under strong coupling regime. The multiple excitons induce complicated spectral changes in plasmon resonance and higher-order plasmons yield drastic quenching for both resonant Raman and fluorescence. A coupled oscillator model composed of plasmon and multiple excitons reproduces the complicated spectral changes. Purcell factors derived from higher-order plasmons reproduce the drastic quenching with considering ultra-fast surface enhanced fluorescence.Comment: 18 pages, 4 figure

Optical Excitation of a Nanoparticle Cu/p-NiO Photocathode Improves Reaction Selectivity for CO₂ Reduction in Aqueous Electrolytes

We report the light-induced modification of catalytic selectivity for photoelectrochemical CO₂ reduction in aqueous media using copper (Cu) nanoparticles dispersed onto p-type nickel oxide (p-NiO) photocathodes. Optical excitation of Cu nanoparticles generates hot electrons available for driving CO₂ reduction on the Cu surface, while charge separation is accomplished by hot-hole injection from the Cu nanoparticles into the underlying p-NiO support. Photoelectrochemical studies demonstrate that optical excitation of plasmonic Cu/p-NiO photocathodes imparts increased selectivity for CO₂ reduction over hydrogen evolution in aqueous electrolytes. Specifically, we observed that plasmon-driven CO₂ reduction increased the production of carbon monoxide and formate, while simultaneously reducing the evolution of hydrogen. Our results demonstrate an optical route toward steering the selectivity of artificial photosynthetic systems with plasmon-driven photocathodes for photoelectrochemical CO₂ reduction in aqueous media