Journal of Optoelectronical NanostructuresJournal of Optoelectronical Nanostructures
http://jopn.miau.ac.ir/
Thu, 17 Jan 2019 23:44:00 +0100FeedCreatorJournal of Optoelectronical Nanostructures
http://jopn.miau.ac.ir/
Feed provided by Journal of Optoelectronical Nanostructures. Click to visit.Noise Equivalent Power Optimization of Graphene- Superconductor Optical Sensors in the Current ...
http://jopn.miau.ac.ir/article_3040_418.html
In this paper, the noise equivalent power (NEP) of an optical sensor based ongraphene-superconductor junctions in the constant current mode of operation has beencalculated. Furthermore, the necessary investigations to optimize the device noise withrespect to various parameters such as the operating temperature, magnetic field, deviceresistance, voltage and current bias have been presented. By simultaneously solving thefree energy and charge carrier density equations of graphene at low temperature, thespecific heat, thermal interaction of electron-phonon and current responsivity of thesensor have been calculated. Using these parameters, the noise equivalent power of thedevice has been obtained. The results show that the behavior of device NEP byincreasing the magnetic field at a constant temperature is at first ascending and thendescending. The NEP value for different temperatures, up to T=80K, has an increasingbehavior and then by further increasing the temperature, the NEP will show decreasingbehavior which is also dependent on the value of the magnetic field. The NEP value isdirectly related to the device voltage and current values, therefore by increasing thevoltage and current, the NEP will increase. Our investigations show that at the constantcurrent bias mode of operation, the final device NEP is independent of the deviceresistance.Fri, 31 Aug 2018 19:30:00 +0100Mathematically modeling of target speed effect on nonlinearity in DTLMI-based nano-metrology system
http://jopn.miau.ac.ir/article_3042_418.html
Jones matrix computation is one of the widely used methods in nonlinearitycalculation in laser interferometers. In this paper, the nonlinearity error in developedthree-longitudinal mode heterodyne interferometer (DTLMI) has been mathematicallymodeled at various speeds, by using Jones matrix calculations. This review has been donedespite the fact that simultaneously the main factors including non-ideal polarization ofthe laser beam and the non-ideal PBS produce nonlinearity. According to the results, itwas found that although nonlinearity error is a pure sinusoid in low velocities, it isn't asingle-sinus and increases in amplitude in high velocities. It was also observed that theeffect of non-ideal PBS on nonlinearity error is less than that of non-ideal laser beam andfrequency of nonlinearity error caused by it is twice more.Fri, 31 Aug 2018 19:30:00 +0100Investigation of thermal tunable nano metallic photonic crystal filter with mirror symmetry
http://jopn.miau.ac.ir/article_3043_418.html
Using the transfer matrix method, the effect of temperature on thetransmission spectra of thermal tunable nano metallic photonic crystal filter has beeninvestigated. Three different materials H (high refractive index material), L (lowrefractive index material) and M as a metallic layer, have been used to make thisstructure. M layer is considered to be Silver. The complex refractive index of Silver is afunction of temperature and wavelength simultaneously so, the structure is tunable withtemperature and incident angle. It is found that the transmission peaks shift by changingtemperature and incident angle. At a given incident angle, they move toward higherwavelengths by increasing the temperature. The temperature dependence oftransmission peaks is linear. At a constant temperature, they move toward the shorterwavelengths by increasing the incident angle. Also by increasing the temperature, due todissipationFri, 31 Aug 2018 19:30:00 +0100Effect of Relative Phase on the Stability of Temporal Bright Solitons in a PT- Symmetric NLDC
http://jopn.miau.ac.ir/article_3044_418.html
In this paper we numerically investigate the effect of relative phase on thestability of temporal bright solitons in a Nano PT- Symmetric nonlinear directionalcoupler (NLDC) by considering gain in bar and loss in cross. We also study the effect ofrelative phase on the output perturbed bright solitons energies, in the range of 0 to 180 . By using perturbation theory three eigenfunctions and correspondingeigenvalues were derived analytically. These eigenvalues behave like equilibrium pointsand are not stable in all cases. Stability of these perturbed solitons under the effect ofrelative phase are examined and show that temporal bright solitons are almost unstable inthe range of 0 to 90 , but they keep their solitary shapes in the range of 90to 180 . In addition the evolution of normalized energies in these ranges areinvestigated.Output pulse energy at bar and cross strongly depend on the relative phase. This effectin a PT-Symmetric NLDC can be used for designing all-optical ultrafast self-switchesand logic gates and Nano structures.Fri, 31 Aug 2018 19:30:00 +0100Comparison of two Public Key Cryptosystems
http://jopn.miau.ac.ir/article_3045_418.html
Since the time public-key cryptography was introduced by Diffie andHellman in 1976, numerous public-key algorithms have been proposed. Some of thesealgorithms are insecure and the others that seem secure, many are impractical, eitherthey have too large keys or the cipher text they produce is much longer than theplaintext. This paper focuses on efficient implementation and analysis of two mostpopular of these algorithms, RSA and ElGamal for key generation and the encryptionscheme (encryption/decryption operation). RSA relies on the difficulty of primefactorization of a very large number, and the hardness of ElGamal algorithm isessentially equivalent to the hardness of finding discrete logarithm modulo a largeprime. These two systems are compared to each other from different parameters pointsof view such as performance, security, speed and applications. To have a goodcomparison and also to have a good level of security correspond to users need thesystems implemented are designed flexibly in terms of the key size.Fri, 31 Aug 2018 19:30:00 +0100Novel Design for Photonic Crystal Ring Resonators Based Optical Channel Drop Filter
http://jopn.miau.ac.ir/article_3046_418.html
Photonic crystal ring resonators (PCRRs) are traditional structures fordesigning optical channel drop filters. In this paper, Photonic crystal channel drop filter(CDFs) with a new configuration of ring resonator is presented. The structure is made ofa square lattice of silicon rods with the refractive index nsi=3. 4 which are perforated inair with refractive index nair=1. Calculations of band structure and propagation ofelectromagnetic field through devices are done by plane wave expansion (PWE) andfinite difference time domain (FDTD) methods, respectively. The simulation shows,100% dropping efficiency and suitable quality factor at 1592. 6 nm wavelength achievedfor this filter. Also, in this paper, we investigate parameters which have an effect onresonant wavelength and transmission spectrum in this CDF, such as refractive index ofinner rods and whole of dielectric rods of the structure. The proposed structure is smallwhich is more suitable for used in the future photonic integrated circuits, wavelengthdivision multiplexing (WDM) systems and optical communication networkapplications. Also, we suggested a heterostructure wavelength demultiplexer iscomposed of four ring resonators. These ring resonators are located in four differentregions (heterostructure) which each region has specific dielectric constant.Fri, 31 Aug 2018 19:30:00 +0100Linear and nonlinear optical properties of a modified Gaussian quantum dot: pressure, ...
http://jopn.miau.ac.ir/article_3047_418.html
In this paper, the effect of pressure, temperature and impurity on the energylevels, binding energy, linear and nonlinear optical properties of a modified Gaussianquantum dot are studied. In this regard, the finite element method is employed to solvethe single electron Schrodinger equation in the effective mass approximation with andwithout impurity at the center of the dot. In addition, the energy levels, the wavefunctions, biding energy, absorption coefficients and refractive index changes fordifferent pressures and temperatures are calculated. The results show that the energylevels decrease by increasing pressure and increase by increasing the temperature forboth, with and without impurity, situations. Also, in the presence of impurity, therefractive index changes are greater than the case without impurity and shift to higherenergies. Furthermore, by increasing the pressure, the refractive index changes increaseand shift to lower energy for both with and without impurity cases. By increasing thepressure and temperature the absorption coefficients decrease and shift to lower energyfor all with and without impurity casesFri, 31 Aug 2018 19:30:00 +0100