•The coupling of two counterpropagating magnetoinductive waves in nonlinear SRRs chain is investigated.•Two coupled NLS equations describing the evolution of the slowly varying amplitude for the two modes are derived.•This system supports backward- and forward-propagating vector solitons of the bright–bright and dark–dark type through a cross-phase modulation.The two coupled counterpropagating nonlinear magnetoinductive wave modes are analyzed theoretically in split ring resonator chain with Kerr nonlinear interaction. Starting from a general nonlinear lattice equation based on a quasi-discreteness approach we derive two coupled nonlinear Schrödinger equations governing the evolution of the slowly varying envelopes of these modes. It is shown that this system supports backward- and forward-propagating vector solitons of the bright–bright and dark–dark type through a cross-phase modulation.

A micro-spectrometer with phase modulation array is investigated in this paper. The vital component of this micro-spectrometer is a micro-interferometer array, which is built on a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). Each element of micro-interferometer array is formed by polymethyl methacrylate (PMMA) grooves with different depth. When we illuminate the surface of the interferometer array, different interference intensity distribution would be formed at the bottom of each micro-interferometer. Optical power of this interferometer can be measured by the pixels of CCD or CMOS. The data can be substituted into a linear system. By solving the linear system with Tikhonov regularization method, spectrum of the incident beam can be reconstructed. Simulation results prove that the detection range of the spectrometer is a wide wavelength range covering from 300 to 1100 nm. Furthermore, the wavelength resolution of the device reaches picometer level. In comparison with conventional spectrometers, the novel spectrometer has distinct advantages of small size, low cost, high resolution, wide spectral measurement range, real-time measurement, and so on.

Based on a coupled meta-atom and metal-nonlinear dielectric-metal nanocavity, nonlinear all-optical strong coupling switches are proposed and numerically investigated. In the absence of the external pumping light, the resonances of the meta-atom are continuously tuned across the one of the nanocavity by changing the size of the meta-atom. The meta-atomic electric dipole and quadrupole interaction with the plasmonic nanocavity is obtained. The characteristic anticrossing behaviors manifest the occurrence of the strong coupling. With the resonance of the meta-atom being tuned to the one of the nanocavity, we dynamically tune the coupled strength of the system by changing intensity (power) of the pumping light and realize the transition from the strong coupling regime to the weak one. This means that this system can be used as an on/off switch in which the strong coupling can be on/off with an external control light, and the on/off states correspond to strong/weak coupling regime, respectively. Such a strong coupling all-optical switching is of considerable interest for applications in nanoscale plasmonic circuits.

The optical properties of a plasmonic surface have been engineered using the rectangular nanohole dimers. One or two transmission peak(s), associated with two symmetrical or asymmetrical transmission channels, has (have) been revealed. We found that, similar to the plasmon coupling of a nanorod dimer, a strong coupling effect is also present in a rectangular nanohole dimer. The effect is closely correlated with the surrounding currents of waveguide modes, which mediate, via the magnetic field, an attractive or repulsive interaction between the dimer holes. The resulted low-energy or high-energy mode will couple with the film surface waves, thus producing the transmission peak with a red- or blue-shift. Moreover, the dependence of coupling modes on the sizes and separation of dimer holes has been systematically investigated, and an anticrossing-like coupling behavior has been suggested. We also suggest that, using the rectangular hole dimers with the perpendicular arrangement, the polarization of light can be manipulated at the desired wavelength. Our results may give a supplement to the Babinet principle, considering the correspondence between the underlying plasmonic interactions in the hole dimer and that in its complementary structure, i.e., the particle dimer.

The enhanced optical transmission (EOT) and the enhanced fluorescence emission (EFE) of the metallic nanohole arrays have been widely studied. Here, the dielectric thickness detection sensor based on these two aspects has been investigated by changing the thickness of the SiO2 layer deposited on the metal surface. We have demonstrated that the Wood anomaly transmission dip in the EOT is better for the dielectric layer thickness detection than the SPP transmission peak. Moreover, in the EFE, by measuring the change of fluorescence emission intensity with the thickness of SiO2 layer, we have obtained higher thickness-detection sensitivity. These results indicate the potential application of metallic nanohole arrays in dielectric thickness detection biosensors.

A maximum fluorescence enhancement of 11 times was achieved by surface plasmon polaritons (SPPs) on a silver nanohole array region in reflection mode, compared to that on the nonarray area. A 30 nm dielectric SiO2 film was sputtered on the silver film as a spacer to separate the fluorophore from silver for attenuation of the fluorescence quenching. An array period of 550 nm and a nanohole radius of 100 nm were optimized to match the most efficient fluorescence excitation and emission of a boron-dipyrromethene fluorophore (BODIPY 630/650) on the array region.Keywords (keywords): fluorescence enhancement; fluorescence quenching; metal film; nanohole array; surface plasmon polaritons; Keywords: ;

The plasmon coupling in a nanorod dimer obeys the exponential size dependence according to the universal plasmon ruler equation. However, it was shown recently that such a model does not hold at short nanorod distances (Nano Lett. 2009, 9, 1651). Here we study nanorod coupling in various cases, including a nanorod dimer with asymmetrical lengths and a symmetrical dimer with varying gap width. The asymmetrical nanorod dimer causes two plasmon modes: one is the attractive lower energy mode and the other the repulsive high-energy mode. Using a simple coupled LC-resonator model, the position of dimer resonance has been determined analytically. Moreover, we found that the plasmon coupling of a symmetrical cylindrical (or rectangular) nanorod dimer is governed uniquely by the gap width scaled for the (effective) rod radius rather than for the rod length. A new plasmon ruler equation without using the fitting parameters has been proposed which agrees well with the finite-difference time-domain calculations. The method has also been extended to study plasmonic waveguiding in a linear chain of gold nanorod particles. A field decay length up to 2700 nm with a lateral mode size of about 50 nm (∼λ/28) has been suggested.

The light emission enhancement behavior from single ZnO nanowires integrated with metallic contacts is investigated by micro-photoluminescence measurements. Apart from surface plasmon polaritons at the air/metal interface, the emission of a single ZnO nanowire can be coupled into guided modes of surface excitonplasmon polaritons (SEPPs). The out-coupling avenues of SEPP guided modes are modeled in the presence of nanostructures, such as corrugation and gratings, on the metal surface. The guided modes of SEPPs in metalcontacted ZnO nanowires are calculated using the effective index method. The enhanced light emission from single semiconductor nanowires shows promise for use in highly efficient nano-emitters and nano-lasers, as well as macroscopic solid state light sources with very high efficiency.

The coupled-wave equations for focused Gaussian beams are derived, where two coupled quasi-phase-matched (QPM) processes, i.e., parametric and sum-frequency processes are involved to achieve the simultaneous generation of efficient three-primary-colors (TPC) in an optical superlattice (OSL). By solving the coupled-wave equations, the optimum conditions for efficient TPC are obtained, for which the negative phase mismatches must be introduced owing to Gouy effect. The results might provide a practical method for the design of a TPC laser.