•The properties of In-Sn alloy films can be influenced by electron-beam irradiation.•In-Sn films have good performance on surface-enhanced Raman scattering(SERS) in this paper.•FDTD simulation results are in good agreement with SERS performance.Electron beam (EB) irradiation experiments on Indium-tin (In-Sn) alloy thin films are reported. The structure and the optical properties of the samples were investigated by atomic force microscopy, X-ray diffraction, UV-vis-NIR double beam spectrometer and Raman system, respectively. Those results show that EB irradiation has the effects of changing the preferred orientation, improving the crystalline, enhancing the absorption, and improving the surface-enhanced Raman scattering (SERS) of samples. In addition, Finite-Difference Time-Domain (FDTD) was performed for the surface plasmon resonance properties of the as-irradiated samples, and the results are in good agreement with the experiments.

The plasmonic bowtie antenna constantly attracts researchers’ interests recently. In this paper, we design and demonstrate polarization sensitive and ultra-broadband excitations of plasmonic waveguides. The structure is composed of a bowtie aperture aligned near a stripe waveguide, which is fabricated on a single silver layer on top of a silica substrate. The dependence of resonance spectra on the arm length of the bowtie aperture is simulated. Only when the incident polarization is parallel to the waveguide direction, the plasmonic bound modes can be correctly excited. Importantly, an extremely wide spectrum bandwidth of 610 nm which covers most of the visible region from 500 nm till the near infrared light of 1 μm is achieved. Our investigations will have intensive applications in next-generation plasmonic integrated chips and functional devices.

•Influences of fabrication errors on the spectral response of GMRF are unavoidable.•Effects of parameters errors of grating and waveguide layer are most remarkable.•Adjusting parameters of grating layer can compensate errors of waveguide layer during fabrication.•All errors can be improved by tuning the refractive index of tunable layer in practice.Guided-mode resonance filters (GMRFs) are very promising optical devices because of their superior spectral performance; however, their fabrication is difficult to implement due to their high intrinsic sensitivity to structural parameters. In this paper, the influence of the error associated with each parameter on the spectral response is investigated in detail. The period, fill factor, and refractive index of the grating layer are found to be the major factors. A versatile method for adjusting the parameter errors is proposed, which includes adjusting certain parameters of the grating layer during fabrication and the refractive index of a tunable layer during practical use. Numerical results show that in the scope of this discussion, almost all the fabrication errors can be compensated by this multi-dimensional adjustment method.

•Theory and design method of the non-subwavelength period GMR filter were illustrated.•Rigorous coupled-wave analysis was used to simulate the GMR structure.•The grating period of 750 nm was fabricated, and the resonant wavelength was 659.76 nm.•Fabrication tolerances about fill factor and grating thickness were investigated for the non-subwavelength filter.A double-layer guided-mode resonance (GMR) filter with a non-subwavelength grating period is proposed for light reflection at oblique incidence. A zinc oxide coated photo-resist grating GMR filter was fabricated, which exhibits good filter properties. For a transverse magnetic-polarized wave, the grating period is larger than the resonance wavelength, which will reduce the difficulties associated with pattern production. The grating structure with a 750 nm period was fabricated utilizing a low cost two-beam interference system, with resonance obtained at 659.76 nm. In addition, the fabrication tolerance concerning the fill factor and the grating thickness were discussed. The device was designed utilizing numerical methods based on a rigorous coupled-wave analysis. Our design may promote the practical application of GMR filters.

Based on the unidirectional propagation property of a single coupler composed of two parallel rectangular slots with different lengths, a near infrared broadband circular surface plasmonic lens is proposed. Multiple identical couplers are arranged on the two concentric circles each of which has half of the total couplers. The numerical investigation using the finite difference in time domain method is performed. The results show that when a radially polarized beam is directed onto the surface plasmonic lens from the side of the substrate, a highly enhanced and confined, dominantly longitudinal polarized nanoscale electromagnetic field spot can be obtained in the center of this circular lens. Various simulations are conducted to optimize the nanostructure. It is demonstrated that, with the optimized lens nanostructure, the extinction ratio of the intensity of the hot spot to the maximum intensity of the off-lens areas is more than 24 within the bandwidth of more than 224 nm. This characterization attributes to the unidirectional propagation property of a single coupler. The high extinction ratio can minimize the outward propagating surface plasmonic energy which may cause the noise and unnecessary coupling with the adjacent nanostructure in the circuit.

•A facile and rapid one-pot synthesis method is presented.•The effects of reaction temperature and reaction time are investigated.•Pure chalcopyrite CISe nanoparticles can be easily synthesized by one-pot method.•The possible reaction mechanism of one-pot method is proposed.•The CISe nanoparticles are highly dispersed with particle size of 50-300 nm.In this work, highly dispersed and near stoichiometric chalcopyrite CuInSe2 nanoparticles were successfully synthesized via a facile and rapid one-pot method. The effects of reaction temperature and reaction time on the crystal phase, morphology, element composition and the absorption spectrum of the as-synthesized CuInSe2 nanoparticles were investigated by x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and UV-Vis-IR spectrophotometer, respectively. The XRD patterns showed that the as-synthesized nanoparticles had pure chalcopyrite phase with the particle size in the range of 50–300 nm confirmed by FE-SEM images. The Vis-IR absorption spectra showed strong absorption in the entire visible light to near-infrared region, the estimated band gap of the as-synthesized nanoparticles matched very well with that of the bulk CuInSe2 material. All results suggested that the as-synthesized CuInSe2 nanoparticles were good light absorber layer material for thin film solar cell.Chalcopyrite and near stoichiometric CuInSe2 nanoparticles were successfully synthesized via a facile and rapid one-pot method. The as-synthesized CuInSe2 nanoparticles are highly dispersed with particle size in the range of 50–300 nm, and the possible reaction mechanism is proposed.

•Highly dispersed chalcopyrite CISe nanoparticles were successfully synthesized.•The phase formation sequence was CuSe → CISe.•The valence of Se in solid intermediates was from −1 to −2.•The amorphous In–Se secondary phase existed in early solid intermediates.•The possible reaction pathway of CISe nanoparticles was proposed.Highly dispersed and near stoichiometric chalcopyrite CuInSe2 nanoparticles were successfully synthesized via a facile and rapid one-pot method. For understanding the reaction pathway, the solid intermediates obtained at different stages of CuInSe2 nanoparticles synthesis process were investigated in detail by powder X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), energy dispersive spectroscopy (EDS) and Raman spectroscopy. The XRD patterns showed that the phase formation sequence was CuSe → CuInSe2. The XPS results indicated that the valences of Cu and Se in CuSe were +1 and −1, respectively. The chemical composition of the solid intermediates revealed the presence of the solid-state In–Se secondary phases in the synthesis process. However, no XRD signals or Raman signals of the solid-state In–Se secondary phase were observed. Based on the experimental results, the possible reaction pathway was proposed.