In this paper we report the study of the electromagnetically induced transparency (EIT)-like transmission in the bright-dark-bright plasmon resonators. It is demonstrated that the interferences between the dark plasmons excited by two bright plasmon resonators can be controlled by the incident light polarization. The constructive interference strengthens the coupling between the bright and dark resonators, leading to a more prominent EIT-like transparency window of the metamaterial. In contrary, destructive interference suppresses the coupling between the bright and dark resonators, destroying the interference pathway that forms the EIT-like transmission. Based on this observation, the plasmonic EIT switching can be realized by changing the polarization of incident light. This phenomenon may find applications in optical switching and plasmon-based information processing.

High sensitivity is obtained at larger resonant incident angle if negative diffraction order of metallic grating is used to excite the surface plasmon. A highly sensitive grating-based surface plasmon resonance (SPR) sensor is designed for the hydrogen detection. A thin palladium (Pd) film deposited on the grating surface is used as transducer. The influences of grating period and the thickness of Pd on the performance of sensor are investigated using rigorous coupled-wave analysis (RCWA) method. The sensitivity as well as the width of the SPR curves and reflective amplitude is considered simultaneously for designing the grating-based SPR hydrogen sensor, and a set of optimized structural parameters is presented. The performance of grating-based SPR sensor is also compared with that of conventional prism-based SPR sensor.

Polymeric fibres with small radii (such as ≤125 nm) are delicate to handle and should be laid down on a solid substrate to obtain practical devices. However, placing these nanofibres on commonly used glass substrates prevents them from guiding light. In this study, we numerically and experimentally demonstrate that when the nanofibre is placed on a suitable dielectric multilayer, it supports a guided mode, a Bloch surface wave (BSW) confined in one dimension. The physical origin of this new mode is discussed in comparison with the typical two-dimensional BSW mode. Polymeric nanofibres are easily fabricated to contain fluorophores, which make the dielectric nanofibre and multilayer configuration suitable for developing a large range of new nanometric scale devices, such as processor–memory interconnections, devices with sensitivity to target analytes, incident polarization and multi-colour BSW modes.

Surface plasmon resonance microscopy (SPRM) with single-direction illumination is a powerful platform for biomedical imaging because of its wide-field, label-free, and high-surface-sensitivity imaging capabilities. However, two disadvantages prevent wider use of SPRM. The first is its poor spatial resolution that can be as large as several micrometers. The second is that SPRM requires use of metal films as sample substrates; this introduces working wavelength limitations. In addition, cell culture growth on metal films is not as universally available as growth on dielectric substrates. Here we show that use of azimuthal rotation illumination allows SPRM spatial resolution to be enhanced by up to an order of magnitude. The metal film can also be replaced by a dielectric multilayer and then a different label-free surface-sensitive photonic microscopy is developed, which has more choices in terms of the working wavelength, polarization, and imaging section, and will bring opportunities for applications in biology.

Chemical synthesized silver nanowires have been proved to be the efficient architecture for Plasmonic waveguides, but the high propagation loss prevents their widely applications. Here, we demonstrate that the propagation distance of the plasmons along a silver nanowire can be extended if this nanowire was placed on a dielectric multilayer substrate containing a photonic band gap, but not placed on a commonly used glass substrate. The propagation distance at 630 nm wavelength can reach 16 μm even that the silver nanowire is as thin as 90 nm in diameter. Experimental and simulation results further show that the polarization of this propagating plasmon mode was nearly parallel to the surface of the dielectric multilayer, so it can be excited by a transverse-electric polarized Bloch surface wave propagating along a polymer nanowire with diameter at only about 170 nm on the same dielectric multilayer. Numerical simulations were also carried out and are consistent with the experiment results. Our work provides a platform to extend the propagation distance of plasmonic waveguide and also for the integration between photonic and plasmonic waveguides on the nanometre scale.

We report a metal-dielectric planar structure which provides high efficiency coupling of fluorescence at distances over 100 nm away from the metal surface. This hybrid metal-dielectric waveguide (MDW) consists of a continuous metal film coated with a dielectric layer. We observed efficient long-range coupling of Rhodamine B on top of a 130 nm layer of silica resulting in a narrow angular distribution of the emission. The high efficiency radiation through the Ag film appears to be due to coupling of the fluorophore to an optical waveguide mode with a long propagation length and a narrow resonance. The results were consistent with simulations. These multi-layer structures can be made using vapor deposition and/or spin coating and the silica surface can be used for conjugation to biomolecules and surface-selective detection. This simple hybrid metal-dielectric structures provides new opportunities for fluorescence sensing, genomics, proteomics and diagnostics.

In this letter, surface plasmons (SPs) excited at the metal-uniaxial dielectric interface are investigated both theoretically and experimentally. The dispersion relations of SPs are derived for the cases where the optical axis of uniaxial medium is parallel the interface or in the incident plane perpendicular to the interface. The theoretical predictions are verified by a Kretschmann–Raether [W. L. Barnes, A. Dereux, and T. W. Ebbesen, Nature (London) 424, 824 (2003)] configuration with azobenzene polymer as photoinduced uniaxial medium. The attenuated total reflection spectra clearly show that the dependence of the SPs propagation properties on the orientations of optical axis, which is consistent with the theoretical analysis. The results of this study provide a useful approach to modulate SPs through adjusting the azobenzene molecular orientation.

Polarization is an intrinsic attribute of optical waves, so manipulating the polarization state of optical surface waves can be of a fundamental importance for the next-generation information and bio-photonics technology. Here, we show theoretically that the polarization of the Bloch surface wave (BSW) on a dielectric multilayer can be transformed between a transverse-electric (TE) state and a transverse-magnetic (TM) state by using the laterally continuous grooves inscribed on this multilayer. This polarization transformation can be enhanced or inhibited by the interference between the reflected BSW beams, which can be tuned by the periodicity and depth of the grooves. The maximum polarization transformation efficiency can be achieved as high as 43% when the number of grooves is increased to 10. A generalized Fresnel formula is proposed to describe the polarization transformation of the BSW beams. Due to this polarization transformation, an anomalous reflection of BSW beams can be realized, which is the inequality between the incident angle and the reflection angle.