Strong enhancement of emission efficiency in GaN light-emitting diodes by plasmon-coupled light amplification of graphene.

Recently, we have demonstrated that excitation of plasmon-polaritons in a mechanically-derived graphene sheet on the top of a ZnO semiconductor considerably enhances its light emission efficiency. If this scheme is also applied to device structures, it is then expected that the energy efficiency of light-emitting diodes (LEDs) increases substantially and the commercial potential will be enormous. Here, we report that the plasmon-induced light coupling amplifies emitted light by ∼1.

Dispersion Curve Engineering of TiO₂/Silver Hybrid Substrates for Enhanced Surface Plasmon Resonance Detection.

As surface plasmon resonance (SPR)-based biosensors are well translated into biological, chemical, environmental, and clinical fields, it is critical to further realize stable and sustainable systems, avoiding oxidation susceptibility of metal films-in particular, silver substrates. We report an enhanced SPR detection performance by incorporating a TiO₂ layer on top of a thin silver film. A uniform TiO₂ film fabricated by electron beam evaporation at room temperature is an effective alternative in bypassing oxidation of a silver film.

Plasmonic metal-dielectric-metal stack structure with subwavelength metallic gratings for improving sensor sensitivity and signal quality.

In this study, we investigated the performance improvement of a localized surface plasmon resonance (LSPR) biosensor by incorporating a metal-dielectric-metal (MDM) stack structure and subwavelength metallic nanograting. The numerical results showed that the LSPR substrate with a MDM stack can provide not only a better sensitivity by more than five times but also a notably improved signal quality. While the gold nanogratings on a gold film inevitably lead to a broad and shallow reflectance curve, the presence of a MDM stack can prevent propagating surface plasmons from interference by locally enhanced fields excited at the gold nanogratings, finally resulting in a strong and deep absorption band at resonance.

Enhancement of field-analyte interaction at metallic nanogap arrays for sensitive localized surface plasmon resonance detection.

We investigated the near-field enhancement of a localized surface plasmon resonance (LSPR) structure based on gold nanograting pairs with a nanosized gap. The results calculated by finite-difference time-domain and rigorous coupled-wave analysis methods presented that the nanogap enclosed by two neighboring nanogratings produced significant confinement and enhancement of electromagnetic fields and allowed a sensitive detection in sensing of surface binding events. Gold gratings with a narrow gap distance less than 10 nm showed enhanced refractive index sensitivity due to the intensified optical field at the nanogap, outperforming the LSPR structure with noninteracting nanogratings.