Plasmon-polaritons can confine an optical wave to a region with dimensions much smaller than the wavelength of the wave in free space. This increases the interaction of optical radiation with material that is suitable for sensing applications. For this reason, in this paper plasmon-polaritons in a nanolayer graphene at mid infrared spectral wavelengths are investigated. Owing to the large wavenumber of plasmon-polaritons in graphene relative to the wavenumber of an optical wave with the same frequency in free space, diffraction grating is used for exciting plasmon-polaritons in graphene. For investigating the effect of relaxation time on the plasmon-polaritons in graphene, relaxation time was varied from  to  and plasmon-polaritons in graphene were simulated by solving electromagnetic wave equation. The results show that while the variation of relaxation time does not affect the period of plasmon-polaritons in graphene, with the decrease of relaxation time confinement and intensity of the plasmon-polaritons in graphene decrease. In addition investigating the reflectance, transmittance and absorption spectra show that the intensity and the location of pick points in the reflection spectra are appropriate for qualitative determination of confinement, and quantitative determination of excitation wavelength of plasmon-polaritons in graphene.

In this study, The surface plasmon excitations in a dimer structure of closely spaced metallic nanospheres with different radii are investigated using the hydrodynamic model. Initially, an expression was derived to calculate this structure's multipolar surface plasmon excitations. Subsequently, the surface plasmon excitations in the dipole approximation were examined.The surface plasmon excitations in a dimer structure of closely spaced metallic nanospheres with different radii are examined using the hydrodynamic model in this study. It has been observed that the energy of in-phase modes is lower than that of out-of-phase modes in longitudinal or transverse excitations. Furthermore, at each separation distance between the nanospheres, the energy difference between in-phase and out-of-phase longitudinal modes is greater than that of transverse modes. The results show that with an increase in the separation distance between the nanospheres, the energies of in-phase modes increase, and the energies of out-of-phase modes decrease. At large separation distances, two plasmon modes are obtained, with the higher energy mode corresponding to the smaller nanosphere and the lower energy mode corresponding to the larger nanosphere. Finally, the local limit results are presented for comparison.

In this paper, the temperature dependence on optical absorption cross section of the core shell bimetallic nanoparticles (NPs) is investigated in quasi static approximation. Temperature dependence of the plasmon resonance is important issue because of recent applications of NPs of noble metal for heat treating of cancer and the computer chips. The effect of temperature on surface plasmon resonance and spectral properties of spherical core-shell NPs are studied by using the Drude Lorentz model. As temperatures increases, the spectrum can be expanded, and thus it causes to expand plasmon resonance absorption and a weak red shift in core-shell NPs. In addition, the temperature dependent absorption cross section of the material depends on the type, structure and geometry of the NPs. The high sensitivity of surface plasmon resonance peaks causes that core shell NPs be completely suitable for medical and optical biosensor applications.

Among the different surface plasmon-based measurement techniques, the detection of phase of surface plasmon is one of the most accurate and sensitive methods. The phase can be measured accurately in different interference based techniques. In this study, the phase and intensity of the surface plasmon was simulated and then the phase shift of surface plasmon wave was experimentally measured by heterodyne polarization interferometry. The response of sensing head to the refractive index change of surrounding medium were obtained. According to the obtained results, the average sensitivity of the phase in the solution of water/alcohol was 0.4426 degree/%gr/ml and for the solution of water/glucose was 1.4765 degree/%gr/ml. The detection limit for solution of water/alcohol and the solution of water/glucose were measured 0.49 %gr/ml and 0.14 %gr/ml, respectively.

In this research, localized surface plasmon resonance spectra for single spherical gold nanoparticles with radius between 20 to 55nm in environments of different refractive indices between 1 and 1.8 has been studied by Finite Different Time Domain method. In this simulations, plasmon resonance frequency is determined for each nanoparticle with optimized mesh size, and is compared with the results of Mie theory. Moreover, using these results, plasmonic propertis of gold nanoshells of various diameters were studied in air (n=1) and water (n=1.33). Plasmon resonance has been calculated for nanoshells and it was concluded that in different environments, gold nanoshells with outer radius of 20 nanometers and diameter of 12 nanometers have their plasmonic spectrum are associated on gold nanosphere with the same outer radius.  frequency for nanoshells has been calculated. The plasmon resonance peak shift for various nanoparticles is plotted versus refractive indices. Finally, the most sensitive and most insennitive of nanoparticles to the refractive index of the environment has been discussed for sensing applications.

In this study, the localized surface plasmon resonance of Copper and Cobalt quantum dots embedded in diamond-like Carbon films, fabricated through radiofrequency plasma-enhanced chemical vapor deposition, were investigated. In addition, the Cobalt and Copper nanoparticles were fabricated through radiofrequency and direct current sputtering methods via co-deposition in a simultaneous sputtering process. Then, the ultravioletvisible-near-infrared spectroscopy, energy dispersive x-ray spectroscopy, atomic force microscopy and field emission scanning electron microscopy were used to analyze the samples and the effect of changes in sputtering conditions on plasmon resonance of Copper and Cobalt quantum dots were also studied. The results showed that the localized surface plasmon resonance of Copper and Cobalt quantum dots embedded in diamond-like Carbon occurred at wavelengths of about 600 and 230 nanometers, respectively. Furthermore, the simultaneous sputtering of elements led to the formation of two types of spectra from plasmon resonance of the samples.

Plasmon-Solitons are quasi-particles resulting from coupling the plasmon modes and solitary solutions. This coupling can be intrinsically resonant in order to form plasmon-solitons with a high localization and large propagation length. This paper deals with the temporal nonlinear dynamics of plasmon-solitons in a plasmonic waveguide. Duffing equation is recognized as the temporal part of the nonlinear amplitude equation governing the plasmonic waveguide. Duffing equation is analytically solved for the low nonlinearity regime. It is shown that the Duffing oscillator waveforms stand for the temporal nonlinear dynamics of plasmon-solitons. The energy exchange of Lorentz-type bright and dark modes gives rise to a Fano resonance. It is thus shown that the interaction of solitons and the formation of plasmonsolitons is inherently nonlinear. It is accordingly indicated that the nonlinear modulation of the plasmon-solitons is achievable via tuning the nonlinearity of the plasmonic waveguide. The results can be appealing for the researchers intending to design the plasmonic waveguides with the high localization as well as the large propagation length. In particular, an all-plasmonic modulation method can be contemplated.

The aim of this work was the optimization of annealing time of silver chip silanized by aminopropyl try ethoxy silane. Silver chip with 50 nm thickness silanized by aqueous silane was annealed in different time at 100 °C. Silanized chips were analyzed via AFM, surface Plasmon resonance sensor and contact angle measurement. Result chips had good optical property for surface Plasmon resonance sensors. By increasing the annealing time, the roughness and chemical stability of silanized chips increased, while their surface plasmon resonance response weakened. Also, annealing increased amine accessibility of chips.

In this paper, scattering of a plane and monochromatic electromagnetic wave from a nano-wire is simulated using surface integral equations. First, integral equationsgoverning unknown fields on the surface is obtained based on Stratton-Cho surface integral equations. Then, the interaction of the wave with a non-plasmonic as well as a palsmonic nano-wire is considered. It is shown that in scattering of the wave from the non-plasmonic nano-wire the simple phenomena of refraction and transmission occur. On the other hand, the interaction of TM polarized light with plasmonic nano-wire excites surface plasmon waves. Simulations show that no surface plasmon is excited in interaction of TE polarized light with plasmonioc nano-wire. It is observed that, while increasing the frequency of incident light, the regime of scattering goes from electrostatic limit to simple geometric limit through diffraction region. In continuation, charge distribution induced by surface plasmon is simulated for different times. The simulation shows that a wave-like surface charge is excited and propagates on the surface.There is a very weak charge distribution within the nano-wire indicating that no light penetrates the wire.

Gold nanoparticles (GNPs) with unique optical properties, such as easy operation and visualized assay, have a great ability to detect different types of analytes. Today, the use of gold nanoparticles has wide applications in the field of medicine and biotechnology, including the detection of microorganisms that cause contamination in water, air and food and it is considered a suitable alternative for chemical and physical methods. New technologies in the design of biosensors based on GNPs provide the ability to identify biological compounds accurately and quickly. One of these technologies is a detection sensor based on surface plasmon resonance (SPR), which based on its optical properties, is capable of very sensitive and specific measurement of biomolecule interactions without time delay. This technology can quantify in a short time the properties of biomolecular mediators (such as oligonucleotides, proteins and bacteria) on the surface, including reaction speed, tendency and concentration of surface mediators. In this review, while investigating the surface plasmon properties of gold nanoparticles, the simple diagnostic applications of gold nanoparticles based on the localized surface plasmon (LSPR) method and detection in biomedicine.