In this research, the nonlinear optical and electronic properties of trigonal carbon-boron-nitride nano flake (C40B3N3H18) are investigated through density functional theory (DFT) calculations. Recently, synthesis and studying properties of hybrid carbon-boron-nitride nanostructures have attracted great interest.The obtained results indicate that although the electronic properties are not affected by this substitution, the nonlinear optical response remarkably enhance in the case of nitrogen atom locates at the top of the nano flake. Due to the potential applications of materials with nonlinear optical response in designing optical devices, the obtained results provide new insights in designing optical devices based on carbon-boron-nitride hybrid nanostructures.

Liquid crystals with high optical and electro-optical responses play an important role in optics and photonics. Therefore, providing a simple method to increase the optical behavior of liquid crystals under the influence of external fields can be considered one of the most challenging research areas. In this experimental work, the effects of temperature and right-handed chiral material with different weight percentages on the refractive indices and optical properties of E7 nematic liquid crystal under the influence of an external electric field were investigated. Despite the reduction of the Kerr constant with increasing the weight percentage of chiral dopants and temperature, the highest amount of optical response in the presence of the electric field was obtained for the nematic liquid crystal doped with 3% of right-handed material. In this case, the value of the Kerr constant is almost 2 times that of pure liquid crystal. This interesting result can be related to the order parameter changes caused by different molecular interactions. Thus, the results obtained in this research can be used as a simple method to increase the optical response of nematic liquid crystals in the presence of an external electric field.

An experimental study over the optical response of thin MoS2 films grownby chemical bath deposition (CBD) method is presented. As two important factors, theeffect of bath temperature and growth time are considered on the photocurrentgeneration in the grown samples. The results show that increasing the growth time leadsto better optical response and higher difference between dark and photocurrent. Forhigher bath temperatures the layer loses its uniformity and the current reduces. Betterperformance of optical response is obtained for t=90min and T=70oC. We also studiedthe effect of post-annealing on the performance and quality of thin films. The I-Vmeasurements show no current flow for annealed films because of rupture of the filmstructure. Temporal response of the films to light source ON and OFF states is alsostudied and the results showed relaxation of photocurrent after about several seconds.The importance of the MoS2 thin films obtained by CBD method is low-temperatureprocess and large area of fabricated layers which can be used in many applications.

Optical and magneto-optical responses of magnetophotonic crystals (MPCs) with a magnetic defect layer sandwiched between two dielectric Bragg mirrors have been investigated, which have potential application in integrated-optics devices. The Bragg mirrors are periodic multilayered films composed of SiO2 and Ta2O5 coatings. By introducing Ce:YIG magnetic defect layer, the enhancement of rotation angle and transmittance value, have been reported. By using of Finite Element Method (FEM), we have simulated the electric field profile in MPCs and investigated the effect of defect layer thickness on Faraday rotation angles. As a result of localization of light at magnetic defect layer and strong light-matter coupling in MPCs, the magneto-optical responses of these structures, are mostly increased near the PBG edges. The structure with a half wavelength optical thickness of defect layer is most suitable for practical applications.

In this paper, copper-gold and copper-silver bimetallic surface nanospheres were formed using ArF excimer laser irradiation with a wavelength of 193 nm and a duration of 15 ns on thin film samples consisting of two metal layers deposited on BK7 glass. The density and shape of the structures were obtained under different irradiation conditions. The optical properties, morphology, and stability of optimal copper-gold and copper-silver structures were compared. The results show that high-density copper-gold core-shell nanospheres with high optical response and stability are produced at a fluence of 150 mJ/cm2 and 5 laser pulses. Silver-copper nanostructures showed lower density, weaker optical response, and lower stability than other nanostructures. The obtained copper-gold nanostructures are suitable for use in plasmonic applications such as biosensors and surface-enhanced Raman spectroscopy.

In this paper, a coupled silver rod-ring nanostructure is proposed for tuning the LSPR wavelength of the plasmonic nanostructure, and the effect of various factors including the length and thickness of the silver ring, as well as the position of the ring on the optical response of the nanostructure is investigated. The results confirm the significant effect of the rod-ring coupling and the wide tunability of the nanostructure LSPR wavelength by changing the position of the ring. Studying the impacts of ring length and ring thickness on the optical response of the nanostructure also shows the importance of choosing the factors. The use of this nanostructure as a biosensor for oral cancer detection indicates that the sensitivity of this nanostructure is a function of the length and thickness of the silver ring as well as the location of the silver ring. However, the sensitivity of the nano biosensor depends on the ring length more than the ring thickness.

We investigate the radiative heat transfer in systems of magneto-optical nanoparticles. The resonance of surface modes due to an external magnetic field results in an anisotropic optical response of these nanoparticles. Using the many-body radiative heat transfer theory, we have investigated the influence of the magnitude and the direction of an external magnetic field on the steady state temperature of system of magneto-optical nanoparticles. Moreover, the influence of configuration symmetry breaking (with change of nanoparticles size) on the net heat exchange and temperatures are investigated in a three body system and the results are compared to that of symmetrical system.

In this paper TiO2 Nanostructures with two different morphologies of naosheet and nanotube are synthesized using chemical vapor deposition and anodize methods. Physical properties of these structures such as morphological, structural and optical are studied using field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD) and Diffusive reflection spectroscopy (DRS). It is found that TiO2 structures with two different morphologies of nanosheets and nanotubes lead to different optical responses which makes TiO2 nanostructures promissing candidate for possible applications. Therefore, morphological control is obtained using optimum experimental conditions with two different methods, which leads to achieving TiO2 nanostructures with desired physical properties.

In this paper two resonant photonic crystals is proposed that their optical response depends not only to the modulation of the dielectric function but also to the interaction of the incident light with the crystal's internal excitations. Alternating layers made of GaAs (as the barrier layer) and InAs/InGaAs quantum dots (dipole active layer) are selected as the main building blocks of the crystals. Structural order is disturbed by adding defects. Transfer Matrix Method (TMM) is applied to evaluate the optical features of the crystals and in order to model the real situation, the roles of the effective exitonic susceptibility besides the homogenous and non-homogenous broadenings are considered in calculations. Dependence of the structures response (including width and wavelength range of the stop band and resonant modes) to the structural parameters such as layers period number, size of the slabs and homogeneity of the layers are studied at the first step. Extracting the optimum values, tunability of the optical features with external parameters such as crystal temperature and light incident angle is explored systematically. Results clearly show the great potential of the proposed crystals for applications such as all optical tunable filters, frequency dividers and switches.

Surface plasmon resonance sensors have been widely considered due to their sensitivity, accuracy and response speed. In order to stimulate surface plasmons, a crisman structure is used in which the metal layer (mainly gold or silver) is placed on the surface of the prism. Due to temperature changes, various factors such as optical properties of the metal, the prism and the surrounding environment can change, which can, in turn, change the response of the plasmonic sensors. In this paper, the thermal effects on the optical response of a surface plasmon resonance sensor were theoretically evaluated. The results showed that the change in temperature led to significant changes in the reflectivity and phase. The greatest effect was due to the changes in the optical properties of the metal layer (gold here) due to temperature changes.