检索结果-南通市图书馆

Chinese Physics B 2015年第1期24卷 269-274页

作者： Seyyed hossein Asadpour h.rahimpour soleimani Department of Physics University of GuilanRasht Iran

We study the absorption-dispersion process and group index of weak probe field in a four-level Er^3＋：YAG *** find that the Er^3＋ion concentration and incoherent pumping field can influence the absorption-dispersion process and group index of weak probe field. Moreover, our results show that Er^3＋ion concentration plays a major role in lasing without inversion and absorption with inversion.

关键词： Er^3+ion concentration incoherent pumping field superluminal

Phase control of group-velocity-based biexciton coherence in a multiple quantum well nanostructure

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第10期23卷 139-146页

作者： Seyyed hossein Asadpour h. rahimpour soleimani Department of Physics University of Guilan

A double cascade-type four-level multiple-quantum-well-based exciton-biexciton transitions are proposed. The study is carried out on a 4.8-rim ZnSe single-quantum well which is embedded into ZnMgSSe cladding layers and pseudomor- phically grown by molecular beam epitaxy on a （0 0 1） GaAs substrate. It is displayed that the exciton spin relaxation and relative phases between applied fields can influence the transient and steady-state behaviors of absorption, dispersion, and group velocity of two weak probe and signal fields. Also, transient behaviors of electron population of different levels are discussed. It is found that the probe or signal amplification occurs in the absence of population inversion.

关键词： exciton-spin relaxation biexciton coherence relative phase between applied fields

Phonon-dependent transport through a serially coupled double quantum dot system

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第5期23卷 510-515页

作者： M.Bagheri Tagani h.rahimpour soleimani Department of Physics University of Guilan

Using Keldysh nonequilibrium Green function formalism and mapping a many-body electron-phonon interaction onto a one body problem, the electron transport through a serially coupled double quantum dot system is analyzed. The influence of the electron-phonon interaction, temperature, detuning, and interdot tunneling on the transmission coefficient and current is studied. Our results show that the electron-phonon interaction results in the appearance of the side peaks in the transmission coefficient, whose height is strongly dependent on the phonon temperature. We have also found that the inequality of the electron-phonon interaction strength in two dots gives rise to an asymmetry in the current-voltage characteristic. In addition, the temperature difference between the phonon and electron subsystems results in the reduction of the saturated current and the destruction of the step-like behavior of the current. It is also observed that the detuning can improve the magnitude of the current by compensating the mismatch of the quantum dots energy levels induced by the electron-phonon interaction.

关键词： quantum dot electron-phonon interaction Keldysh nonequilibrium Green function formalism,current-voltage characteristic

Phase Control of Transient Optical Properties of Quantum-Dot Nanostructure via Terahertz Signal Radiation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2014年第11期31卷 77-80页

作者： Seyyed hossein Asadpour h. rahimpour soleimani Department of Physics University of Guilan Rasht Iran

We theoretically analyze the transient properties of a probe field absorption dispersion in a quantum-dot nanos- trueture driven by terahertz signal radiation. here a four-level quantum-dot nanostructure is designed numerically by Schrodinger and Poisson＇s equations. We show that in the presence of the Thz signal, the medium becomes phase dependent and the absorption dispersion can be dramatically influenced by the relative phase between applied fields.

关键词： Semiconductor quantum dots

Charge and spin-dependent thermal efficiency of polythiophene molecular junction in presence of dephasing

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2015年第10期24卷 576-583页

作者： Z.Golsanamlou M.Bagheri Tagani h.rahimpour soleimani Department of Physics University of Guilan

The charge and spin-dependent thermoelectric properties of different lengths of polythiophene in a molecular junction are investigated using the B ¨uttiker probe method within Green function formalism in linear response regime. The coupling of the molecular chain to three-dimensional ferromagnetic electrodes is described by a tight-binding model for both parallel and antiparallel spin configurations. The decrease of height of transmission probability peaks and thermoelectric coefficients are observed in the presence of the B ¨uttiker probes. The reduction is more intensive in the strong dephased *** show that the spin magnetothermopower is bigger than the charge magnetothermopower due to the larger difference between the spin thermopowers with respect to the charge ones. In addition, we observed that the kind of carriers participating in the thermoelectric transport depends on the number of the thiophene rings.

关键词： polythiophene Green function thermoelectric coefficients Buttiker probes ferromagnetic elec-trodes

Comparison of absorption dispersion and optical bistability behaviors between open and closed four-level tripod atomic systems

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2015年第9期24卷 250-256页

作者： R.Karimi S.h.Asadpour S.Batebi h.rahimpour soleimani Department of Physics University of Guilan

In this paper we investigate the optical properties of an open four-level tripod atomic system driven by an elliptically polarized probe field and compare its properties with the corresponding closed system. Our results reveal that absorption,dispersion, group velocity, and optical bistability of the probe field can be manipulated by adjusting the phase difference between the two circularly polarized components of a single coherent field and cavity parameters, i.e., the atomic exit rate from cavity and atomic injection rates.

关键词： absorption dispersion optical bistability

Impact of coupling geometry on thermoelectric properties of oligophenyl-base transistor

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第2期26卷 420-427页

作者： S Ramezani Akbarabadi h rahimpour soleimani M Bagheri Tagani Z Golsanamlou Computational Nanophysics Laboratory (CNL) Department of Physics University of Guilan Rasht P. O. Box 41335-1914 Iran

Thermal and electron transport through organic molecules attached to three-dimensional gold electrodes in two different configurations, namely para and meta with thiol-terminated junctions is studied theoretically in the linear response regime using Green＇s function formalism. We used thiol-terminated（–Sh bond） benzene units and found a positive thermopower because the highest occupied molecular orbital（hOMO） is near the Fermi energy level. We investigated the influence of molecular length and molecular junction geometry on the thermoelectric properties. Our results show that the thermoelectric properties are highly sensitive to the coupling geometry and the molecular length. In addition, we observed that the interference effects and increasing molecular length can increase the thermoelectric efficiency of device in a specific configuration.

关键词： coupling geometry figure of merit Green's function oligophenyl thermopower

Coherent Control of the Goos–hnchen Shifts in a Four-Level N Type Atomic Medium

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2014年第12期61卷 864-870页

作者： Parisa Maboodi Soheila hemmatzadeh Seyyed hossein Asadpour h.rahimpour soleimani Research Institute for Applied Physics and Astronomy University of Tabriz Tabriz Iran Department of Physics University of Guilan Rasht Iran

The behavior of the Goos–h¨anchen(Gh) shifts of the reflected and transmitted probe light beams is theoretically investigated. In a fixed geometrical configuration, the effect of quantum interference induced by spontaneous emission on the phase control of the Gh shifts is analyzed in this paper. It is found that in a four-level N-type atomic system as an intracavity medium, the Gh shifts of the reflected and transmitted probe light beam are completely phase dependent.

关键词： Goos–hanchen shift quantum interference group index

Thermoelectric Properties of Single Molecule Junction in Presence of Dephasing and Different Coupling Geometries

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2015年第9期64卷 361-366页

作者： Z.Golsanamlou M.Bagheri Tagani h.rahimpour soleimani Department of Physics University of Guilan

The thermoelectric properties of a benzene molecule coupled to three-dimensional metallic electrodes are examined in the presence of dephasing processes using Green function formalism in the linear response regime. The three different kind of configurations(ortho, meta and para) are taken into account for the coupling between the molecule and electrodes. Results show that the thermoelectric properties of the single molecular junction are strongly dependent on the coupling geometry. Our results predict that the thermoelectric efficiency is increased in specific geometry as a consequence of interference effects. It is found that the dephasing effects result in the reduction of the thermoelectric efficiency.

关键词： nanostructures electrical conductivity thermal con

Roles of Atomic Injection Rate and External Magnetic Field on Optical Properties of Elliptical Polarized Probe Light

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2016年第1期65卷 57-65页

作者： R.Karimi S.h.Asadpour S.Batebi h.rahimpour soleimani Department of Physics University of Guilan

In this paper we investigate the optical properties of an open four-level tripod atomic system driven by an elliptically polarized probe field in the presence of the external magnetic field and compare its properties with the corresponding closed *** result reveals that absorption,dispersion and group velocity of probe field can be manipulated by adjusting the phase difference between the two circularly polarized components of a single coherent field,magnetic field and cavity parameters *** atomic exit rate from cavity and atomic injection *** show that the system can exhibit multiple electromagnetically induced transparency windows in the presence of the external magnetic *** numerical result shows that the probe field in the open system can be amplified by appropriate choice of cavity parameters,while in the closed system with introduce appropriate phase difference between fields the probe field can be *** it is shown that the group velocity of light pulse can be controlled by external magnetic field,relative phase of applied fields and cavity *** changing the parameters the group velocity of light pulse changes from subluminal to superluminal light propagation and vice versa.

关键词：椭圆偏振光原子系统注入速率光学性质外磁场封闭系统超光速传播群速度