The rouge waves in an optically injected semiconductor lasers are receiving a lot of interest. In this work, the generating and controlling of the rogue waves in semiconductor lasers have been investigated. For this purpose, the laser’s rate equations are solved numerically in a specified time interval, then the field amplitude and the intensity versus time are calculated and analyzed. To solve the rate equations, the famous finite deference method (FDM) is used. Also the rouge waves are counted using the standard definition that is mentioned in the context. Furthermore, the effects of the injection strength and the detuning frequency on the rogue wave’s occurrence are studied. Results show that by increasing the injection amplitude, the number of rogue waves decreases significantly, so that rouge waves vanish at the large values of the injection amplitude. Also increasing the detuning frequency, reduces the number of rogue waves and this reduction is more sensitive at the large injection amplitude. تفاصيل المقالة

Here, the population transfer between two specific levels of Cesium atom
under the influence of chirped laser source has been numerically investigated. The main
goal of this study is the engineering of the population transfer between the 62S1/2 and 62P1/2
levels of Cesium which is corresponding to its D1 transition line using a chirped laser
source. Constructing the system Hamiltonian, as well as the initial and boundary
conditions, the time-dependent Schrödinger equations are numerically solved and the
population versus time for different physical parameters has been investigated. The final
population of each state is calculated and discussed for changing the parameters such as
laser intensity, laser frequency and chirping parameter. The results show that using the
chirped laser source with tuned parameters, we can arbitrarily control the population of
levels.

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In this paper, the noise equivalent power (NEP) of an optical sensor based on
graphene-superconductor junctions in the constant current mode of operation has been
calculated. Furthermore, the necessary investigations to optimize the device noise with
respect to various parameters such as the operating temperature, magnetic field, device
resistance, voltage and current bias have been presented. By simultaneously solving the
free energy and charge carrier density equations of graphene at low temperature, the
specific heat, thermal interaction of electron-phonon and current responsivity of the
sensor have been calculated. Using these parameters, the noise equivalent power of the
device has been obtained. The results show that the behavior of device NEP by
increasing the magnetic field at a constant temperature is at first ascending and then
descending. The NEP value for different temperatures, up to T=80K, has an increasing
behavior and then by further increasing the temperature, the NEP will show decreasing
behavior which is also dependent on the value of the magnetic field. The NEP value is
directly related to the device voltage and current values, therefore by increasing the
voltage and current, the NEP will increase. Our investigations show that at the constant
current bias mode of operation, the final device NEP is independent of the device
resistance. تفاصيل المقالة

Abstract : The variation of the electrical resistivity of a material in the external
magnetic field is known as magneto resistance. This phenomenon has been attracted
both theoretical and experimental researchers in miniaturization of magneto meters in
the recent years. In this paper, the magneto resistance of an inhomogeneous two
dimensional conductor with ladder geometry is simulated by using a two dimensional
resistor network model. Maxwell's equations have been solved for a point of lattice
considered as disk and then, its magneto resistance was calculated using a network
model. The results illustrate that the magneto resistance depends on the specific
resistance ratios and their locations. Moreover, the results demonstrate when
inhomogeneity is added properly, the magneto resistance will be increased, otherwise it
will be reduced. The results also show that for special values of physical parameters
especially the inhomogeneity, the magneto resistance is diverged at special magnetic
field. تفاصيل المقالة

Abstract
Efficient and coherent transfer of population between different quantum states. In this study, we delve into the investigation of population transfer in two coupled Λ-type three-level systems using the STIRAP technique. Our research focuses on understanding the dynamics and control of population transfer within these systems. The system Hamiltonian is constructed based on the physical condition of the coupled structure, then the respective time-dependent Schrodinger equation is solved numerically. By analyzing the adiabatic conditions, we explore the interaction between the two coupled Λ-type systems examine the role of various parameters, such as the time of the peak amplitude, and determine the pulse width. Furthermore, we observe the impact of interaction on the transition probability, comparing coupled systems to uncoupled systems. The findings of this study shed light on the underlying mechanisms of STIRAP and contribute to the development of advanced quantum control techniques. تفاصيل المقالة