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In this paper, electric and magnetic resonances induced in the ellipsoidal dielectric nanoparticles in the optical range have been analyzed. Circular displacement currents excited inside the elliptical nano-particles by the incident light result in magnetic dipolar resonance in the dielectric nanoparticles. Kerker’s type scattering is observed due to the mutual interference of electric and magnetic resonances. The effect on the resonance conditions with the variation in the relative permittivity from Er= 5 to Er= 20 of the ellipsoidal nanoparticle has been observed. It has been analyzed that peaks of electric and magnetic resonances come closer by decreasing the electric permittivity of the nanoparticle, which leads to the increase in the directionality in the forward direction, as verified using Generalized Kerker’s condition. Further, far field scattering patterns have been obtained using the finite element method. Here, the electric and magnetic resonances have been optically induced up to quadrupolar modes. There is enhancement of the directionality in the forward direction when electric and magnetic resonances are in phase. Further, the effect of size of the linear array of ellipsoidal nanoparticles on the directionality has been analyzed. It has been observed that there is increase in the directivity by increasing the chain of the nanoparticles. Thus, the ellipsoidal nanoparticles can lead to the design of low loss and highly directional optical nanoantennas.

In this paper, enhanced image resolution by modification in the two dimensional (2-D) photonic crystal structures has been proposed. The equal frequency contour (EFC) analysis have been done using plane wave expansion method which shows that the structure exhibits an effective isotropic refractive index, neff = -1 at a normalized frequency of ω = 0.2908(2πc/a) for TM polarization, located near the second band. At ω = 0.2908(2πc/a) for TM polarization, the considered PhC structure behaves as a superlens, as analyzed using the finite difference time domain (FDTD) method. The image resolution and stability of the photonic crystal slab lens has been enhanced by creating disorder in the top and bottom layer of the PhC structure. The intensity field distributions of the optimized structure exhibit the enhanced image quality with full width at half maximum (FWHM) of 0.311 λ. The proposed structure can also be used to sense the different type of blood constituents.

Mie resonance in square arrays of dielectric rods has been reported. Arrays in square lattice of dielectric rods with very high permittivity in air have been considered. Light of transverse electric mode has been launched on the square array of cylindrical dielectric rods. Mie resonance of first two orders has been observed in the dielectric rods, due to which electric and magnetic dipoles are generated in the rods. Thus, electric resonance and magnetic resonance at different frequencies has been observed with material of high value of permittivity.

The terahertz and mid-infrared region of the electromagnetic spectrum is relatively new area of interest and incorporates a wide range of applications from image sensing to spectroscopy and many more yet to be discovered. In the area of metamaterials many new designs have been discovered, but “chevrons” shaped split ring resonators (ch-SRRs) in the mid-infrared region has not been studied to the best of our knowledge. This paper presents the analysis and simulation of ch-SRRs in the mid infrared region. Tunability of SRRs is important for various industrial and scientific applications and hence this paper analyzes the tunability of the ch-SRRs by variation of angle. The device is simulated in two configurations i.e., one with two chevrons shaped SRRs on the same plane of the dielectric substrate and the other with each of the two chevron shaped SRRs on the opposite plane of the substrate. Gold SRRs is used, since we are working in the terahertz region Lorentz-Drude model is employed to incorporate the losses. The ch-SRRs have been embedded upon the silicon substrate. The models are designed and simulated in COMSOL and result is shown in MATLAB. The results obtained for reflectance are of particular interest. The effective medium parameters viz. Impendence, permittivity, permeability and refractive index obtained for the split ring resonator are also evaluated. This design shows sharp results for reflectance which can be used in sensors application.

In this paper, we have calculated the highly efficient generation of the slow light based on the Stimulated Brillouin scattering (SBS) in a small core As 2 Se 3 chalcogenide PCF. A Brillouin gain coefficient, g B . of 9.05 10-9 m.W-1 is found around the acoustic frequency of 8.08 GHz in small core diameter of 1.69 μm with 1.5 μm 2 effective mode area at 1550 nm. A Brillouin gain of 77.3 dB was achieved with only 10 mW pump power in a 10-m fiber length, which leads to the optical time delay of 94 ns. In terms of the proposed figure of merit, it shows 2.77 dB/mW/m which is about 110 times more efficient than conventional single-mode fibers. These fibers are expected to have potential applications in realization of compact slow light devices.

A rectangular core photonic crystal fiber design in As2Se3 chalcogenide glass has been reported for mid-infrared supercontinuum generation. The structural parameters have been tailored for all normal dispersion profile. The proposed structure possesses nonlinearity (Υ) as large as 20956 W-1 km-1 at 2800 nm wavelength with very low and flat dispersion of -2.38 ps/(nm×km). We have generated supercontinuum spectra spanning 1480 – 9990 nm using only 4 mm length of proposed photonic crystal fiber pumped with femtosecond optical pulses of peak power of 500 W at 2800 nm.

A plasmonic cavity incorporating surface plasmon polariton(SPP) mode is proposed to be used as infiltrated sensor employing sub-wavelength confinement of light. Truly Plasmonic TM mode is obtained and the mode profile of the Plasmonic Photonic Crystal Cavity (PPCC) structure is shown using three dimensional Finite Difference Time Domain Method (3D-FDTD) method. The cavity length of the structure is optimized to obtain single mode localization of resonating wavelength and the change in the cut-off wavelength is observed by varying refractive indices of the content of air holes. A transverse magnetic (TM) Plasmonic bandgap of the structure is shown and hence, the transmission spectra, Quality factor are calculated.

Plasmon like excitation is observed at the interface between one-dimensional periodic array of air holes in silicon (Si) with ferroelectric polyvinylidene fluoride (PVDF) as a substrate to obtain subwavelength confinement of surface Plasmon modes at terahertz (THz) frequencies. A truly Plasmonic TM mode is obtained confined at the interface of PVDF layer and the 1D perforated dielectric slab and the mode field distribution of the structure is demonstrated using three dimensional (3D) Finite Difference Time domain Method (FDTD) method. It is shown that PVDF are promising materials for strongly confined THz wave propagation in Surface Plasmon photonic crystal. The transmission, confinement and hence the propagation length of the plasmonpolariton like terahertz surface modes sustained by the structure are studied using Finite difference time domain (FDTD) method. Further, the propagation characteristics of surface Plasmon polariton (SPP) which can be controlled by the structure geometry is discussed.