Silicene, a zero-gap semi-metallic advanced material, has received much attention due to its extr... more Silicene, a zero-gap semi-metallic advanced material, has received much attention due to its extraordinary electronic and optical characteristics, which could be used in plasmonics nano-devices. This material presenting as a tunable material without degrading its high carrier mobility. By applying the rigorous numerical techniques, the optical and electrical properties of silicene at high terahertz frequencies are calculated here. Beneath the influence of environmental effects such as the Fermi level, temperature, and external electric field, on the optical conductivity and refractive index of silicene are investigated using the tight-binding model. The effect of Fermi level from zero to 1 eV, external electric field from zero to 2.5 eV, and temperature from 5 to 400 K are investigated on the optical properties of silicene. One of the interesting features of Silicene is its adjustable bandgap, which we are present here.
Using plasmonic devices, by converting incoming light into surface plasmon polaritons on the bord... more Using plasmonic devices, by converting incoming light into surface plasmon polaritons on the border between metal and dielectric at the same frequency, faster signal processing and light transmission is possible in the very compact space. In this paper we tried to design a new structure for slow light creation based on plasmonic induced transparency in a circular metal-dielectric-metal resonator. Length of the proposed plasmonic system is about 600 nm and the radius of the ring is equal to 5.5 micrometers. First we used gold as the metal of the structure then changed it to silver. In both cases, the dielectric material is poly-methyl meta-acrylic, the pump wavelength is 1550 nm and the signal wavelength is 860 nm. Simulation results show that in the first case, where the metal is gold, slow light features are much better in comparison with the second case, where the metal is silver.
Method of the analog of electromagnetically induced transparency (EIT) in plasmonic metal– dielec... more Method of the analog of electromagnetically induced transparency (EIT) in plasmonic metal– dielectric–metal (MIM) waveguide is proposed by using symmetric side-coupled elliptic cavities and simulated by Finite-difference time-domain (FDTD). In this paper comparison and investigation in novel structure creating a slow light device based on plasmonic induced transparency (PIT), in ring resonator of elliptic shape with metal-dielectric-metal is examined. In this proposed structure, a ring resonator with two input ports and two output ports for occurrence and investigate of plasmon's mode in a waveguide system is examined. Poly metyle meta acrylate is used for dielectric that is sandwiched between gold metal layers. Wavelength of the pump for transparency of media is 1550 nm and wavelength of small signal in this structure is 820 nm. The length of this proposed device is 500 nm. In the proposed structure, we will get the real and imaginary of refractive index and slow down factor. T...
Majlesi Journal of Telecommunication Devices, 2015
In this article, we have given the size of the coupling constant, a system of quantum electro-dyn... more In this article, we have given the size of the coupling constant, a system of quantum electro-dynamics in weak coupling regime, strong and very strong case our analysis and simulation. Also by choosing the type of quantum system and the electrical field of the electromagnetic wave, the size of Rabi frequency to the extent that we are less than excited states and photons in the cavity decay rate is. In this case, the interaction between the quantum system and electromagnetic field coupling regime is weak. It is one of the properties of quantum light emitting modes of the cavity modes can be in resonance with each other, resulting in a sudden increase in the spontaneous emission rate, causing a sharp peak in the density of the spontaneous emission spectrum. The nature of this regime leads to appropriate in light production applications, such as it is possible to increase efficiency, reduce the threshold lasers emitting light in alignment with the vertical cavity structure light emitti...
In this paper we introduce a band pass filter based on plasmonic induced transparency in nanomete... more In this paper we introduce a band pass filter based on plasmonic induced transparency in nanometer scale, which includes a resonant cavity and a metal-dielectric-metal waveguide. Wide stop-band, sharp transition band, small dimensions and tunability are the advantages of the filter structure. The finite-difference timedomain method is used to analyze and simulate this structure.
We have proposed an all-optical switch for logic gates application using two-dimensional Photonic... more We have proposed an all-optical switch for logic gates application using two-dimensional Photonic Crystal (PC) waveguide based on phase difference between incident beams that is created by point defect. A PC with triangular lattice made using Si dielectric rods in the air is used as the main structure of the device. Our proposed devices are XOR and OR logic gates. We have shown if initial phase difference between two inputs is π then they interfere destructively to realize the logical functions. This optical gate has many advantages than electrical logic gates such as low power consumption, high speed about light velocity and simple structure. This device is applicable in frequency range 0.44-0.46 (a/λ), but we use frequency a/λ=0.452 for low dispersion and set the lambda to 1.55 µm. The plane wave expansion method (PWE) is used to photonic band gap (PBG) calculation, and finite-difference time-domain method (FDTD) is used to compute the electrical field distribution in the photonic ...
In this paper, a multilayer/monolayer black phosphorus (BP)-based nanostructure is presented to d... more In this paper, a multilayer/monolayer black phosphorus (BP)-based nanostructure is presented to detect the avian influenza virus. The nanostructur is a grating arrangement made of BP over SiO2 or Al2O3 substrate. To achieve the transmission spectrum, depend on the changes in the lateral length of BP, namely (L = 100, 150, 170 nm) as well as the complex refractive index of each of three viruses types (H1N1, H5N2, H9N2) in the THz range, the structure is numerically simulated by 3D Finite Difference Time Domain (3D-FDTD) method. The change in resonance frequency is greater for the H9N2 virus because the real part of its refractive index is relatively larger. Here, too, the rate of change is examined based on the different thicknesses of the H9N2 virus. Also, changes in the refractive index of the environment have been used to calculate important parameters in the sensors, such as sensitivity, FWHM, and figure of merit. Overall, this platform provides a promising platform for detecting...
The analysis, and realization of a tunable polarization beam splitter based on the plasma dispers... more The analysis, and realization of a tunable polarization beam splitter based on the plasma dispersion effect at near infrared frequencies are presented. By utilizing graphene as a tunable optical material, various types of splitter including TE and TM are implemented. The structure considered here supports graphene plasmons whose dispersion properties can be harnessed by applying an external voltage to the graphene. By utilizing this feature, coupling of the incident light to the graphene plasmons of the structure is used to enhance the extinction ratio of the proposed structure. The output extinction ratio reached to the values as high as 21 dB and the footprint was reduced to 1290nm×m×m. This provides a path for development of novel practical on-chip applications such as plasmonic rotator devices.
In this study, a novel, two-dimensional photonic crystal-based structure for the 2-to-4 optical d... more In this study, a novel, two-dimensional photonic crystal-based structure for the 2-to-4 optical decoder is presented. The structure consists of 23 rows and 14 columns of chalcogenide rods that are arranged in a square lattice with a spatial periodicity of 530 nm. The bias and the optical signals are guided toward the main waveguide through the three waveguides. Two unequal powers are applied to the input ports to approach the different intensities proportional to four working states into the main waveguide. Four cavities including the nonlinear rods are in response to drop the optical waves toward the output ports. To calculate the band diagram and the spatial distribution of the electric and magnetic fields, the plane wave expansion and the finite difference time domain methods have been used. The delay time of the designed structure is obtained around 220 fs, which is less than one for the previous structures. Furthermore, the gap between the margins for logic 0 and 1 is equal to ...
Carbon nanotube transistor is a spotlight components for toxic gas monitoring. In this regard, we... more Carbon nanotube transistor is a spotlight components for toxic gas monitoring. In this regard, we present a new toxic gas molecules sensor base on a single-walled carbon nanotube transistor and use the Poisson and Schrodinger equations in a self-consistent manner and is modeled using non-equilibrium Green’s function. The reaction between gaseous molecules and single-walled carbon nanotubes can harness the charge and potential level inside the channel, which changes the electrical characteristics of the device. Investigations carried out over a 20-nm channel and at a temperature range between 200 and 400 K shows that the conductivity and current–voltage characteristic of the proposed Nano-sensor depend on temperature and gas conditions. According to the simulation results, the decrease in the temperature decreases the OFF-state current of the tunneling carbon nanotube field-effect transistor which leads to a decrease in the leakage current and the band-to-band tunneling. In addition, due to the temperature rise, the sensitivity is increased, and by increasing the dielectric constant of the gas, the on-state current of the device will also increase significantly. The maximum sensitivity for Carbonyl Chloride is 630 (nm/RIU).
Silicene, a zero-gap semi-metallic advanced material, has received much attention due to its extr... more Silicene, a zero-gap semi-metallic advanced material, has received much attention due to its extraordinary electronic and optical characteristics, which could be used in plasmonics nano-devices. This material presenting as a tunable material without degrading its high carrier mobility. By applying the rigorous numerical techniques, the optical and electrical properties of silicene at high terahertz frequencies are calculated here. Beneath the influence of environmental effects such as the Fermi level, temperature, and external electric field, on the optical conductivity and refractive index of silicene are investigated using the tight-binding model. The effect of Fermi level from zero to 1 eV, external electric field from zero to 2.5 eV, and temperature from 5 to 400 K are investigated on the optical properties of silicene. One of the interesting features of Silicene is its adjustable bandgap, which we are present here.
Using plasmonic devices, by converting incoming light into surface plasmon polaritons on the bord... more Using plasmonic devices, by converting incoming light into surface plasmon polaritons on the border between metal and dielectric at the same frequency, faster signal processing and light transmission is possible in the very compact space. In this paper we tried to design a new structure for slow light creation based on plasmonic induced transparency in a circular metal-dielectric-metal resonator. Length of the proposed plasmonic system is about 600 nm and the radius of the ring is equal to 5.5 micrometers. First we used gold as the metal of the structure then changed it to silver. In both cases, the dielectric material is poly-methyl meta-acrylic, the pump wavelength is 1550 nm and the signal wavelength is 860 nm. Simulation results show that in the first case, where the metal is gold, slow light features are much better in comparison with the second case, where the metal is silver.
Method of the analog of electromagnetically induced transparency (EIT) in plasmonic metal– dielec... more Method of the analog of electromagnetically induced transparency (EIT) in plasmonic metal– dielectric–metal (MIM) waveguide is proposed by using symmetric side-coupled elliptic cavities and simulated by Finite-difference time-domain (FDTD). In this paper comparison and investigation in novel structure creating a slow light device based on plasmonic induced transparency (PIT), in ring resonator of elliptic shape with metal-dielectric-metal is examined. In this proposed structure, a ring resonator with two input ports and two output ports for occurrence and investigate of plasmon's mode in a waveguide system is examined. Poly metyle meta acrylate is used for dielectric that is sandwiched between gold metal layers. Wavelength of the pump for transparency of media is 1550 nm and wavelength of small signal in this structure is 820 nm. The length of this proposed device is 500 nm. In the proposed structure, we will get the real and imaginary of refractive index and slow down factor. T...
Majlesi Journal of Telecommunication Devices, 2015
In this article, we have given the size of the coupling constant, a system of quantum electro-dyn... more In this article, we have given the size of the coupling constant, a system of quantum electro-dynamics in weak coupling regime, strong and very strong case our analysis and simulation. Also by choosing the type of quantum system and the electrical field of the electromagnetic wave, the size of Rabi frequency to the extent that we are less than excited states and photons in the cavity decay rate is. In this case, the interaction between the quantum system and electromagnetic field coupling regime is weak. It is one of the properties of quantum light emitting modes of the cavity modes can be in resonance with each other, resulting in a sudden increase in the spontaneous emission rate, causing a sharp peak in the density of the spontaneous emission spectrum. The nature of this regime leads to appropriate in light production applications, such as it is possible to increase efficiency, reduce the threshold lasers emitting light in alignment with the vertical cavity structure light emitti...
In this paper we introduce a band pass filter based on plasmonic induced transparency in nanomete... more In this paper we introduce a band pass filter based on plasmonic induced transparency in nanometer scale, which includes a resonant cavity and a metal-dielectric-metal waveguide. Wide stop-band, sharp transition band, small dimensions and tunability are the advantages of the filter structure. The finite-difference timedomain method is used to analyze and simulate this structure.
We have proposed an all-optical switch for logic gates application using two-dimensional Photonic... more We have proposed an all-optical switch for logic gates application using two-dimensional Photonic Crystal (PC) waveguide based on phase difference between incident beams that is created by point defect. A PC with triangular lattice made using Si dielectric rods in the air is used as the main structure of the device. Our proposed devices are XOR and OR logic gates. We have shown if initial phase difference between two inputs is π then they interfere destructively to realize the logical functions. This optical gate has many advantages than electrical logic gates such as low power consumption, high speed about light velocity and simple structure. This device is applicable in frequency range 0.44-0.46 (a/λ), but we use frequency a/λ=0.452 for low dispersion and set the lambda to 1.55 µm. The plane wave expansion method (PWE) is used to photonic band gap (PBG) calculation, and finite-difference time-domain method (FDTD) is used to compute the electrical field distribution in the photonic ...
In this paper, a multilayer/monolayer black phosphorus (BP)-based nanostructure is presented to d... more In this paper, a multilayer/monolayer black phosphorus (BP)-based nanostructure is presented to detect the avian influenza virus. The nanostructur is a grating arrangement made of BP over SiO2 or Al2O3 substrate. To achieve the transmission spectrum, depend on the changes in the lateral length of BP, namely (L = 100, 150, 170 nm) as well as the complex refractive index of each of three viruses types (H1N1, H5N2, H9N2) in the THz range, the structure is numerically simulated by 3D Finite Difference Time Domain (3D-FDTD) method. The change in resonance frequency is greater for the H9N2 virus because the real part of its refractive index is relatively larger. Here, too, the rate of change is examined based on the different thicknesses of the H9N2 virus. Also, changes in the refractive index of the environment have been used to calculate important parameters in the sensors, such as sensitivity, FWHM, and figure of merit. Overall, this platform provides a promising platform for detecting...
The analysis, and realization of a tunable polarization beam splitter based on the plasma dispers... more The analysis, and realization of a tunable polarization beam splitter based on the plasma dispersion effect at near infrared frequencies are presented. By utilizing graphene as a tunable optical material, various types of splitter including TE and TM are implemented. The structure considered here supports graphene plasmons whose dispersion properties can be harnessed by applying an external voltage to the graphene. By utilizing this feature, coupling of the incident light to the graphene plasmons of the structure is used to enhance the extinction ratio of the proposed structure. The output extinction ratio reached to the values as high as 21 dB and the footprint was reduced to 1290nm×m×m. This provides a path for development of novel practical on-chip applications such as plasmonic rotator devices.
In this study, a novel, two-dimensional photonic crystal-based structure for the 2-to-4 optical d... more In this study, a novel, two-dimensional photonic crystal-based structure for the 2-to-4 optical decoder is presented. The structure consists of 23 rows and 14 columns of chalcogenide rods that are arranged in a square lattice with a spatial periodicity of 530 nm. The bias and the optical signals are guided toward the main waveguide through the three waveguides. Two unequal powers are applied to the input ports to approach the different intensities proportional to four working states into the main waveguide. Four cavities including the nonlinear rods are in response to drop the optical waves toward the output ports. To calculate the band diagram and the spatial distribution of the electric and magnetic fields, the plane wave expansion and the finite difference time domain methods have been used. The delay time of the designed structure is obtained around 220 fs, which is less than one for the previous structures. Furthermore, the gap between the margins for logic 0 and 1 is equal to ...
Carbon nanotube transistor is a spotlight components for toxic gas monitoring. In this regard, we... more Carbon nanotube transistor is a spotlight components for toxic gas monitoring. In this regard, we present a new toxic gas molecules sensor base on a single-walled carbon nanotube transistor and use the Poisson and Schrodinger equations in a self-consistent manner and is modeled using non-equilibrium Green’s function. The reaction between gaseous molecules and single-walled carbon nanotubes can harness the charge and potential level inside the channel, which changes the electrical characteristics of the device. Investigations carried out over a 20-nm channel and at a temperature range between 200 and 400 K shows that the conductivity and current–voltage characteristic of the proposed Nano-sensor depend on temperature and gas conditions. According to the simulation results, the decrease in the temperature decreases the OFF-state current of the tunneling carbon nanotube field-effect transistor which leads to a decrease in the leakage current and the band-to-band tunneling. In addition, due to the temperature rise, the sensitivity is increased, and by increasing the dielectric constant of the gas, the on-state current of the device will also increase significantly. The maximum sensitivity for Carbonyl Chloride is 630 (nm/RIU).
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